JP4835065B2 - Manufacturing method of imaging device - Google Patents

Description

  The present invention relates to an image pickup device manufacturing method for manufacturing an image pickup device including a light receiving element. The present invention relates to a manufacturing method of an imaging element to be manufactured.

  In recent years, two-dimensional image sensors are used in digital cameras and video cameras. Also, linear sensors (one-dimensional image sensors) are used in facsimiles and copiers.

  Such an image sensor (imaging element) includes a light receiving element (photoelectric conversion element), and detects incident light incident on the image sensor by the light receiving element. Incident light is detected after being converted into an electrical signal by the photoelectric conversion element.

  Note that a light receiving element such as a CMOS or CCD has high sensitivity even in a region outside the visible light wavelength region (for example, a wavelength region of 400 nm to 700 nm) which is a human visual sensitivity region. Moreover, it has a high sensitivity also about the wavelength range (henceforth "infrared region". For example, it is a wavelength range of 700 nm-1100 nm) on the wavelength side longer than a visible light wavelength range.

  The light receiving element receives incident light via the organic color filter. That is, on the light incident side of each light receiving element, organic color filters for the three primary colors of light are installed in order to extract a specific color component from the incident light and perform color separation. Incident light is color-separated by the organic color filter, and the color component to be observed is observed by the light receiving element.

  In addition, a light receiving element converts into an electrical signal according to the intensity of incident light. In other words, only the brightness of the incident light is detected, and the color of the incident light is not determined. Therefore, the light incident side of the light receiving element is provided with organic color filters of red (R), green (G), and blue (B), which are the three primary colors of light, so that the light from the subject is color-separated and specified. Taking out the light.

  Specifically, light that has passed through each color filter of red, green, and blue is incident on a light receiving element that faces each color filter, and is converted into an electrical signal by each light receiving element. Then, an output value (usually a voltage value is output) obtained by photoelectric conversion is synthesized, and the photographing target is reproduced as a color image.

  However, since the organic color filter does not have a function of cutting light in the infrared region (infrared light), light outside the human visual sensitivity region (for example, longer wavelength than 700 nm) may be incident on the light receiving element. For this reason, the color of the photographing target obtained by the image sensor may be different from the color of the photographing target observed by human eyes.

  Therefore, an infrared cut filter is used. By using this infrared cut filter, the light from which the infrared light is cut is incident on each color filter, so that the influence of the infrared light can be reduced. A specific example of the relationship between the human visual sensitivity, the sensitivity of the light receiving element (SPD sensitivity), and the transmittance of the infrared cut filter that is preferable for the sensitivity of the light receiving element is shown in FIG.

  As shown in the example of FIG. 35, the light receiving element has sensitivity also in the infrared region. Therefore, if infrared observation of the light receiving element is suppressed by the infrared cut filter, measurement close to human visual sensitivity becomes possible. That is, if the light of the hatched portion in FIG. 35 is cut by the infrared cut filter, the light receiving element can measure close to human visual sensitivity.

  By the way, there are two types of infrared cut filters, a reflection type and an absorption type. The relationship between the wavelength of light and the transmittance in the reflection type infrared cut filter and the absorption type infrared cut filter is shown in FIG. 36, for example.

  The reflective infrared cut filter is configured by forming an inorganic multilayer film on a glass plate, for example. A reflective infrared cut filter using an inorganic multilayer film has a high infrared cut function for incident light in a direction perpendicular to the filter surface. However, it does not have a sufficient cutting function for infrared rays with an angle such as oblique incidence, and it is difficult to realize this.

  On the other hand, an absorption type infrared cut filter absorbs infrared rays by utilizing absorption of light by dyes or copper ions. A general absorption-type infrared cut filter is configured by putting a metal ion such as copper ion or an organic pigment in a base material such as inorganic glass.

  Further, when comparing the reflection type infrared cut filter and the absorption type infrared cut filter, the absorption type infrared cut filter is less expensive than the reflection type infrared cut filter. Further, the absorption type infrared cut filter has better performance of the infrared ray cut function of incident light having an angle than the reflection type infrared cut filter. Therefore, in general, the absorption type infrared cut filter tends to be used more than the reflection type infrared cut filter.

  In addition, in order to supplement the cut function of the reflective infrared cut filter by the inorganic multilayer film and reduce the influence of oblique incidence or re-incidence of infrared rays, the absorption type infrared cut filter and the reflective infrared cut filter by the inorganic multilayer film are used. May be used together, but it is not common. This is because the structure becomes complicated when an absorption type infrared cut filter and a reflection type infrared cut filter are used in combination.

  In general image pickup devices, an optical system including a lens or the like is provided on the light incident side of the light receiving device in order to observe light from the subject. In order to prevent the observation result from being affected by infrared rays, an infrared cut filter may be inserted into the optical system of such an image sensor (see, for example, Patent Literature 1 and Patent Literature 2).

  Patent Document 1 has a function of correcting color purity by selectively cutting light in a specific wavelength region at a boundary between red light and green light and / or a boundary between green light and blue light, and A solid-state imaging device including a color purity correction filter having a function of cutting infrared rays is described.

  Further, in Patent Document 2, an infrared absorber capable of significantly reducing the transmittance in the infrared light region and transmitting the light in the visible light wavelength region is added to provide an infrared cut capability, and a spectral filter is provided on the front surface of the image sensor body. A color image pickup device in which is arranged is described.

As described above, in Patent Documents 1 and 2, the infrared cut filter is inserted into the optical system so as to cover the entire light receiving element such as a CMOS or CCD.
JP 2000-19322 A JP-A-63-73204

  However, if an absorption type infrared cut filter is included in the optical system of the image sensor, it is difficult to reduce the size of the image sensor. This is because the absorption-type infrared cut filter requires a thickness of about 1 to 3 mm in order to sufficiently absorb infrared rays.

  Moreover, when manufacturing a camera member using an absorption-type infrared cut filter, a process for incorporating the infrared cut filter into the lens system is required, making it difficult to reduce manufacturing costs.

  Furthermore, the image sensor of Patent Document 1 and Patent Document 2 includes an infrared cut filter that covers the entire front surface of the image sensor body. For this reason, infrared rays are cut with respect to all the light receiving elements provided in the imaging element. As a result, there may be a difference between observation by the light receiving element and human visual sensitivity.

  Further, for example, in Patent Document 2, as shown in FIGS. 2 and 10 of Patent Document 2, the infrared cut filter absorbs light in a human visible light wavelength region of 550 nm to 700 nm. For this reason, if infrared rays are cut with respect to all the light receiving elements provided in the image sensor, the red and green sensitivities may decrease, and in particular, the red sensitivity may decrease.

  By the way, when the transmittance of the color filter is low, the amount of light reaching the light receiving element is reduced, and the image quality is deteriorated (dark image). For example, FIG. 37 is a graph showing an example of the spectral transmittance of the color filter in the three primary colors of red, green, and blue light, but the vertex of the transmittance of green and blue is only about 80%.

  In recent years, the demand for increasing the number of pixels in an image sensor has increased, and the pixels have been miniaturized. Specifically, the pixel pitch (distance between pixels) is below 3 μm and is becoming around 2 μm. As described above, when the pixel pitch is a fine pixel in the vicinity of 2 μm, the area per pixel is reduced, so that the amount of light incident on the light receiving element is reduced. For this reason, the low transmittance of the color filter means a decrease in sensitivity of the light receiving element, which causes a decrease in image quality (a dark image).

  In addition, as shown in FIG. 35, the SPD sensitivity of the light receiving element shows a high value in the wavelength region near 700 nm, but decreases as it goes to the short wavelength region. In particular, in the vicinity of the blue wavelength range (400 nm to 500 nm), the sensitivity is about half that of red.

  Furthermore, as shown in FIG. 37, the transmittance of the blue color filter is lower than the transmittance of the red and green color filters.

  From the above viewpoint, in an image sensor having color filters of the three primary colors of red, green, and blue, the sensitivity of the light receiving element is low in the blue region, and the blue color filter is lower than the transmittance of the red and green color filters. It can be seen that the transmittance is lower.

  For this reason, in the conventional imaging device, the sensitivity of blue is lower than that of red or green, and it is difficult to accurately reproduce the color balance.

  Note that, as shown in the spectral transmittance of the absorption-type infrared cut filter in FIG. 36, the absorption-type infrared cut filter has a region that absorbs light even in the visible light wavelength region of approximately 550 nm to 700 nm. This visible light wavelength range of 550 nm to 700 nm corresponds to the wavelength range of red or green light. Therefore, when an absorption type infrared cut filter is used for the image sensor, there is a problem that the sensitivity of red particularly decreases. That is, in an imaging device that cuts infrared rays with an absorption-type infrared cut filter, not only blue but also red color reproducibility may be impaired.

  Therefore, a technique using a complementary color filter composed of yellow (Y), magenta (M), and cyan (C) has been proposed to cope with a decrease in sensitivity of the light receiving element due to a decrease in the amount of incident light. In this technique, the combined light of red and green can be extracted by using a yellow (Y) color filter. By using a magenta (M) color filter, the combined light of red and blue can be extracted. By using a cyan (C) color filter, combined light of green and blue can be extracted.

  In other words, since the complementary color filter transmits light of two colors, the transmittance can be increased, and a decrease in the amount of incident light can be suppressed.

  However, in order to extract light of the three primary colors of red, green, and blue red from the light that has passed through the color filters of the complementary colors of yellow, magenta, and cyan, for example, blue = (cyan + magenta-yellow) / 2, green = ( Cyan + yellow-magenta) / 2, red = (magenta + yellow-cyan) / 2, etc. It is necessary to perform a complicated calculation for calculating a value corresponding to the primary color.

  Therefore, it may be difficult to express a vivid color close to the primary color.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a manufacturing method for manufacturing a thin imaging device having good color balance, color reproducibility, and image quality.

  In order to achieve the above object, the present invention takes the following measures.

  In the present invention, “a photolithography method using a developer (hereinafter also referred to as a photolithography method)” means that a photosensitive resin layer is subjected to pattern exposure and then developed with a developer such as an alkaline solution to form a predetermined pattern. It refers to the process of forming and, if necessary, performing a hardening process.

  In the present invention, “dry etching” is a technique in which a workpiece having an etching resistant layer is placed in the apparatus, and a portion of the workpiece exposed from the etching resistant layer is etched by ions or radicals generated in the apparatus. Say.

  That is, in the formation of a color filter by “a photolithography method using a developer”, a color resist is applied, pattern exposure is performed, and development is performed to form a color filter. On the other hand, in the formation of a color filter by “dry etching”, a color filter is formed by applying a photoresist on a color resist, pattern exposure, developing, and then dry etching.

The invention corresponding to claim 1 includes a plurality of photoelectric conversion elements provided on a semiconductor substrate, a plurality of types of color filters individually formed on the plurality of photoelectric conversion elements and having different colorant content ratios, and transparent An image pickup device manufacturing method for manufacturing an image pickup device including a filter, the step of forming, by dry etching, one or more types of high-rate color filters having a relatively high color material content ratio among the color filters And forming a low ratio color filter other than the high ratio color filter by a photolithography method using a developer, and forming a transparent resin layer so as to cover the high ratio color filter and the low ratio color filter. And a process for forming a transparent filter.

According to a second aspect of the present invention, there are provided a plurality of photoelectric conversion elements provided on a semiconductor substrate, a plurality of types of color filters individually formed on the plurality of photoelectric conversion elements and having different color material content ratios, and transparent An image pickup device manufacturing method for manufacturing an image pickup device including a filter, the step of forming, by dry etching, a high ratio color filter having the highest color material content ratio among the color filters, and the high ratio color filter And forming a transparent filter by forming a transparent resin layer so as to cover the high ratio color filter and the low ratio color filter, and a step of forming a low ratio color filter other than the above by a photolithography method using a developer. An image pickup device manufacturing method including a process.

According to a third aspect of the present invention, there are provided a plurality of photoelectric conversion elements provided on a semiconductor substrate, a plurality of types of color filters formed individually on the plurality of photoelectric conversion elements and having different color material content ratios, and transparent An image pickup device manufacturing method for manufacturing an image pickup device provided with a filter, the step of forming a colored resin layer to be a high ratio color filter having the highest color material content ratio among the color filters, and the colored resin layer A step of forming a photoresist layer; a step of patterning the photoresist layer to expose a colored resin layer in the pattern of the high-ratio color filter; and a colored resin layer exposed from the pattern of the photoresist layer In the region different from the high ratio color filter on the semiconductor substrate after the dry etching step and the formation of the high ratio color filter, A step of forming a low ratio color filter other than the high ratio color filter by a photolithography method using a developer; and a transparent resin layer so as to cover the high ratio color filter and the low ratio color filter on the semiconductor substrate. A step of spin-coating and applying, a step of thermally curing the transparent resin layer to form a planarization layer including a transparent filter, and dry etching the planarization layer on the photoelectric conversion element to form a microlens. And a forming process.

According to a fourth aspect of the present invention, the high ratio color filter has a transmittance of 10% or less in a wavelength region of 400 nm to 600 nm, and a transmittance of 90% or more in a wavelength region of 750 nm to 1100 nm. An imaging device manufacturing method corresponding to any one of claims 1 to 3 .

According to a fifth aspect of the present invention, the high-ratio color filter and the low-ratio color filter have a first wavelength region that exhibits a transmittance of 10% or less in a wavelength region of 400 nm to 600 nm, and the first wavelength is a manufacturing method of an imaging device corresponding to any one of claims 1 to 4 having a wavelength range of 90% or more transmittance in the wavelength region of 450nm~1100nm a longer wavelengths than frequency.

According to a sixth aspect of the present invention, the high ratio color filter and the low ratio color filter include a yellow filter used for extracting a yellow component of light, and a red filter used for extracting a red component of light. And a correction filter having a transmission suppression characteristic in the visible light wavelength range and having a transmission characteristic on the longer wavelength side than the visible light wavelength range, and manufacturing an imaging device corresponding to any one of claims 1 to 5 Is the method.

Invention corresponding to claim 7, wherein the transparent filter, in the manufacturing method of the imaging element corresponding to any one of claims 1 to 6 having a transmittance of 90% or higher in the wavelength range of 400nm~1100nm is there.

Invention corresponding to claim 8, wherein the transparent filter is a method of manufacturing an imaging element corresponding to any one of claims 1 to 7 to absorb ultraviolet rays shorter wavelengths than 400 nm.

<Action>
The known photolithography method takes a process of pattern exposure to a photosensitive resin layer, development with a developer composed of an alkaline solution, and a hardening process such as heating with a hot plate if necessary. Form a pattern. However, this method tends to leave a residue at the site where the photosensitive resin is to be removed. In particular, when the content of the pigment in the photosensitive resin is high, a residue is likely to occur. Moreover, when the content rate of the pigment was high, the pattern shape was also broken. The residue becomes a foreign substance and blocks light, resulting in black defects and lowering the image quality. Further, the collapse of the pattern shape has also caused a decrease in image quality.

Accordingly, the invention corresponding to the first to third aspects provides a step of forming a high ratio color filter having a high color material content ratio among the color filters by dry etching, and a high ratio color filter. And a step of forming a color filter with a low ratio other than the above by a photolithography method, so that the residue of the colored resin can be removed as compared with the case of forming the high ratio color filter with a photolithography method. Moreover, it can form without destroying the shape of a high ratio color filter. Thus, an image pickup device including a plurality of photoelectric conversion elements provided on a semiconductor substrate and a plurality of types of color filters individually formed on the photoelectric conversion elements, the color balance and color reproducibility It is possible to provide a method for manufacturing an image pickup device that produces a thin image pickup device with good image quality.

The invention corresponding to claim 4 has a transmittance of 10% or less in the wavelength region of 400 nm to 600 nm in addition to the action corresponding to claims 1 to 3, and a transmittance of 90% or more in the wavelength region of 750 nm to 1100 nm. An image pickup device manufacturing method for manufacturing an image pickup device including a high-ratio color filter having a rate can be provided.

The invention corresponding to claim 5 has the first wavelength region exhibiting a transmittance of 10% or less in the wavelength region of 400 nm to 600 nm in addition to the action corresponding to claims 1 to 4 , and the first wavelength A method for manufacturing an image pickup device for manufacturing an image pickup device including a high ratio color filter having a wavelength range longer than that of the region and having a wavelength range of 90% or more in a wavelength range of 450 nm to 1100 nm and a low ratio color filter Can be provided.

The invention corresponding to claim 6 includes the yellow filter used for extracting the yellow component of light, and the red filter used for extracting the red component of light, in addition to the operations corresponding to claims 1 to 5. An image pickup device for manufacturing an image pickup device having a high-ratio color filter and a low-ratio color filter including a correction filter having a transmission suppression characteristic in the visible light wavelength region and having a transmission property on a longer wavelength side than the visible light wavelength region Can be provided.

The invention corresponding to claim 7 manufactures an image pickup device that manufactures an image pickup device including a transparent filter having a transmittance of 90% or more in the wavelength region of 400 nm to 1100 nm in addition to the operations corresponding to claims 1 to 6. Can provide a method.

The invention corresponding to claim 8 can provide an image pickup device manufacturing method for manufacturing an image pickup device including a transparent filter that absorbs ultraviolet rays in a wavelength region shorter than 400 nm, in addition to the operations corresponding to claims 1 to 7 .

  ADVANTAGE OF THE INVENTION According to this invention, the color balance, color reproducibility, and image quality are favorable, and the manufacturing method of the image pick-up element which manufactures a thin image pick-up element can be provided.

  In particular, according to the manufacturing method of the present invention, it is possible to provide an imaging device that suppresses a decrease in blue sensitivity and improves color balance. In addition, it is possible to provide an imaging device that suppresses a reduction in red sensitivity that occurs when an infrared cut filter is provided, and improves red color reproducibility. Furthermore, an increase in the thickness of an optical system including a lens can be prevented, and a downsized imaging device can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same elements are denoted by the same reference numerals and description thereof is omitted.

<First Embodiment>
In the present embodiment, an image sensor that includes a light receiving element such as a CMOS or a CCD, and that provides a filter layer on the light incident side of the light receiving element to observe a color component to be observed will be described.

  FIG. 1 is a plan view illustrating an example of an arrangement state of filters in the image sensor according to the present embodiment. In FIG. 1, an example of the state of the filter viewed from the light incident side is shown.

  FIG. 2 is a cross-sectional view showing an example of an image sensor according to the present embodiment. FIG. 2 shows a cross section taken along the line I-I ′ of FIG. 1. In FIG. 2, the case where the light receiving element is a CMOS is shown as an example, but the same applies to the case where the light receiving element is a CCD. Hereinafter, the same applies to other cross-sectional views of the imaging device.

  The imaging device 1 according to the present embodiment includes a filter layer 2 used for extracting light of a specific color component from incident light, and light receiving elements 3W, 3Y, 3R, and 3Blk that observe the incident light via the filter layer 2. And an arithmetic unit 4.

  The filter layer 2 includes a transparent filter 2W, a yellow filter 2Y, a red filter 2R, and a correction filter 2Blk. Here, one unit of color separation is formed by a configuration in which each of the transparent filter 2W, the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk is combined. Further, the transparent filter 2W, the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk are appropriately arranged to form a surface that is adjacently arranged in a grid pattern. The four filters of the transparent filter 2W, the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk need only be arranged adjacent to each other, and are not limited to the arrangement shown in FIG.

  The transparent filter 2W is preferably transmitted without absorbing light having a long wavelength of 400 nm or longer. For example, the transparent filter 2W is desirably a filter having a transmittance of 95% or more for light having a wavelength of 400 nm or more with reference to transparent glass having a refractive index n of about 1.5. Such a transparent filter 2W is formed of a phenol-based, polystyrene-based, acrylic-based resin or the like, but is preferably formed of a polystyrene-based resin, preferably an acrylic-based resin, from the viewpoint of heat resistance.

  The yellow filter 2Y is a filter used for extracting a yellow component (light obtained by combining a red component and a green component) from incident light. The yellow filter 2Y is a complementary color filter. In general, a complementary color filter has a higher light transmittance than a color filter of three primary colors of red, green, and blue.

  The red filter 2R is a red color filter used for extracting a red component of incident light. In general, a red color filter has higher transmittance than a green color filter or a blue color filter, which are other color filters of the three primary colors.

  The correction filter 2Blk is a filter that has transmission suppression characteristics in the visible light wavelength range and has transmission characteristics on the longer wavelength side than the visible light wavelength range, and the transmittance in the infrared range is higher than the transmittance in the visible wavelength range. Also has high characteristics. Since the correction filter 2Blk has a transmission suppression characteristic (low transmission characteristic) in the visible light wavelength region, it looks black.

  In the present embodiment, the correction filter 2Blk is formed as a single filter with a color material obtained by mixing a violet color material and a red color material, but by stacking the violet filter and the red filter, You may form it superposed optically.

  The incident light receiving element 3W, the yellow light receiving element 3Y, the red light receiving element 3R, and the correction light receiving element 3Blk, which are light receiving elements, are arranged on the side opposite to the light incident side of the filter layer 2, and convert received light into an electrical signal. The observation data value is obtained. A one-to-one combination of a light receiving element and a filter corresponds to a pixel.

  The incident light receiving element 3W is associated with the transparent filter 2W, and observes incident light via the transparent filter 2W.

  The yellow light receiving element 3Y is associated with the yellow filter 2Y and observes incident light via the yellow filter 2Y.

  The red light receiving element 3R is associated with the red filter 2R and observes incident light via the red filter 2R.

  The correction light receiving element 3Blk is associated with the correction filter 2Blk, and observes incident light via the correction filter 2Blk.

  The computing unit 4 includes a blue computing unit 4B, a green computing unit 4G, and a red computing unit 4R. Based on the observation data values Dw, Dy, Dr, and Dblk by the incident light receiving element 3W, the yellow light receiving element 3Y, the red light receiving element 3R, and the corrected light receiving element 3Blk, the calculation unit 4 observes the blue observation data value Db and green. It has a function of obtaining the data value Dg and the corrected red observation data value HDr.

  That is, if the colors corresponding to the transparent filter 2W, yellow filter 2Y, red filter 2R, and correction filter 2Blk are white (W), yellow (Y), red (R '), and black (Blk), respectively, they will be described later. Based on Expressions (1) to (3), data values of the three primary colors of blue (B), green (G), and red (R) light can be obtained.

Blue (B) = White (W) -Yellow (Y) (1)
Green (G) = Yellow (Y) -Red (R ′) (2)
Red (R) = Red (R ′) − Black (Blk) (3)
The blue calculation unit 4B subtracts the observation data value Dy observed by the yellow light receiving element 3Y from the observation data value Dw observed by the incident light receiving element 3W to obtain a blue observation data value Db (= Dw−Dy). Ask for.

  The green calculation unit 4G subtracts the observation data value Dr observed by the red light receiving element 3R from the observation data value Dy observed by the yellow light receiving element 3Y, and obtains the green observation data value Dg (= Dy−Dr). Ask.

  The red calculation unit 4R subtracts the observation data value Dblk observed by the corrected light receiving element 3Bik from the observation data value Dr observed by the red light receiving element 3R, and corrects the corrected red observation data value HDr (= Dr− Dblk).

  FIG. 2 shows a cross section that crosses the red filter 2R and the correction filter 2Blk and also crosses the red light receiving element 3R and the correction light receiving element 3Blk, but crosses the other filters and the other light receiving elements. The same structure is applied to the cross section.

  The semiconductor substrate 5 has an incident light receiving element 3W, a yellow light receiving element 3Y, a red light receiving element 3R, and a correction light receiving element 3Blk formed and arranged on the light incident side.

The planarizing layer 6 is laminated on the light incident side surface of the semiconductor substrate 5 on which the incident light receiving element 3W, the yellow light receiving element 3Y, the red light receiving element 3R, and the correction light receiving element 3Blk are formed. Thereby, the transparent filter 2W, the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk can be formed on a flat installation surface. Note that the planarization layer 6 may be omitted in order to make the imaging device 1 thin. On the light incident side of the flattening layer 6, a transparent filter 2W, a yellow filter 2Y, a red filter 2R, and a correction filter respectively corresponding to the incident light receiving element 3W, the yellow light receiving element 3Y, the red light receiving element 3R, and the correction light receiving element 3Blk. 2Blk is disposed, and the filter layer 2 is formed. A resin layer (transparent flattening layer) 7 is laminated on the light incident side of the filter layer 2.

  The planarizing layer 6 is formed of a thermosetting acrylic resin to which an ultraviolet absorber is added. The reason why the ultraviolet absorber is added to the planarizing layer 6 is that when a color filter is formed by photolithography, a good shape filter is formed by preventing halation from the underlying semiconductor substrate 5. It is for forming.

  Further, as the material of the planarizing layer 6, a resin containing one or a plurality of resins such as acrylic, epoxy, polyimide, urethane, melamine, polyester, urea, and styrene can be used. .

  The resin layer 7 is laminated on the light incident side of the filter layer 2. On the light incident side of the resin layer 7, microlenses 8 corresponding to the incident light receiving element 3W, the yellow light receiving element 3Y, the red light receiving element 3R, and the correction light receiving element 3Blk are provided.

  The microlens 8 is disposed above each transparent filter 2W, yellow filter 2Y, red filter 2R, and correction filter 2Blk so as to make a pair with each transparent filter 2W, yellow filter 2Y, red filter 2R, and correction filter 2Blk. Yes. The microlens 8 is formed of an acrylic resin or the like, and improves the light condensing property to the incident light receiving element 3W, the yellow light receiving element 3Y, the red light receiving element 3R, and the correction light receiving element 3Blk.

  As described above, the correction filter 2Blk is formed of a single layer resin in which a red pigment and a violet pigment are mixed with a transparent resin. However, the correction filter 2Blk is not limited to the structure shown in FIG.

  The optical superposition here may be realized in a single layer by a colored resin in which color materials (pigments / pigments) constituting color filters of different colors as shown in FIG. 2 are mixed, as shown in FIG. As described above, it may be realized by a laminated structure of color filters of two or more different colors. Further, two or more color materials may be used for color and transmittance adjustment.

  Thus, by optically superimposing two or more color filters, the transmittance of the correction filter 2Blk is the product of the transmittances of the respective color filters to be superimposed. Therefore, as in the present embodiment, the correction filter 2Blk is formed by optical superposition so that the correction filter 2Blk has transmission suppression characteristics in the visible light wavelength range and transmission characteristics in the longer wavelength side than the visible light wavelength range. Can be created. In FIG. 3, a correction filter 2Blk is configured by stacking a violet filter 2V and a red filter 2R as two or more types of filters.

  In this embodiment, the film thickness of each filter is 1.4 μm, and the pixel pitch (the pitch of the transparent filter 2W, the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk) is 2.6 μm. The planarization layer 6 is formed of a thermosetting acrylic resin to which an ultraviolet absorber is added, and has a film thickness of 0.3 μm.

  In the present embodiment, the transparent filter 2W is formed of an alkali-soluble photosensitive acrylic resin (refractive index n = 1.55) to a thickness of about 1 μm.

  In this embodiment, the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk, which are color filters, add a predetermined organic pigment to the transparent resin (photosensitive acrylic resin) used for forming the transparent filter 2W. It is formed using a dispersed colored photosensitive resin.

  In addition, as an organic pigment used for formation of the yellow filter 2Y, for example, C.I. Pigment Yellow150 is used. Alternatively, a mixed pigment obtained by mixing C.I. Pigment Yellow 139 with C.I. Pigment Yellow 150 may be used.

Moreover, as an organic pigment used for formation of the red filter 2R, for example, a mixture of CI Pigment Red177, CI Pigment Red48: 1, and CI Pigment Yellow139 is used.
Moreover, as an organic pigment used for formation of the correction filter 2Blk, for example, CI PigmentViolet23 and an organic pigment used for the red filter 2R (for example, a mixture of CI Pigment Red177, CI Pigment Red48: 1, and CI Pigment Yellow139) A mixture with is used.
FIG. 4 is a graph showing an example of the spectral transmittance of the transparent filter 2W, the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk.

  The image sensor 1 calculates (subtracts) based on the observation data values Dw, Dy, Dr, and Dblk from the respective light receiving elements, and obtains the observation data values Db, Dg, and HDr of the three primary colors of blue, green, and corrected red. obtain. That is, it can be considered that the imaging device 1 includes a blue filter, a green filter, and a red filter in appearance (virtually) by performing this calculation.

  FIG. 5 is a graph illustrating an example of the spectral transmittance of the apparent blue filter, green filter, and red filter obtained by the calculation of the image sensor 1.

  Spectral transmittances of the apparent blue filter, green filter, and red filter of the image sensor 1 shown in FIG. 5, and spectral transmittances of the conventional blue color filter, green color filter, and red color filter shown in FIG. The spectral transmittance of the apparent blue filter, green filter, and red filter of the image sensor 1 has the following characteristics.

  That is, the apparent transmittance of the blue filter and the green filter of the image pickup device 1 is characterized in that the transmittance is higher than that of the conventional blue color filter and green color filter in the wavelength range of each color.

  In particular, the apparent blue filter has a higher transmittance in the blue wavelength region than the conventional blue color filter.

  For this reason, in the imaging device 1, the sensitivity of blue is improved and the color balance is improved.

  The blue observation data value Db, the green observation data value Dg, and the corrected red observation data value HDr obtained by the image sensor 1 are calculated by subtracting the observation data values in the infrared region.

  For this reason, the spectral transmittance curves of the apparent blue filter, green filter, and red filter are suppressed in the infrared region compared to the spectral transmittance curves of the conventional blue color filter, green color filter, and red color filter. (Cut).

  Therefore, in the image sensor 1 according to the present embodiment, the infrared cut filter can be omitted and can be thinned.

  In addition, it is possible to prevent a reduction in red sensitivity that occurs when an absorption type infrared cut filter is provided, and it is possible to improve red color reproducibility.

  Hereinafter, the imaging device 1 according to the present embodiment and a conventional imaging device will be described in comparison.

  First, the “apparent color filter” will be described.

  FIG. 6 is a graph showing an example of actual spectral characteristics of a conventional image sensor.

  The spectral characteristics of the conventional image sensor are obtained by multiplying the sensitivity of the light receiving element (FIG. 6A) and the transmittance of the filter disposed on the light incident side of the light receiving element (FIG. 6B). It is considered equivalent to the product value, and is expressed as shown in FIG.

  As shown in FIG. 6C, the blue color filter in the conventional image sensor has a lower transmittance than the other green and red color filters, and the sensitivity of the light receiving element in the blue wavelength region is other than that. Lower than the sensitivity in the green and red wavelength regions. For this reason, in the conventional image sensor, when the sensitivity ratio is obtained, blue / green is too smaller than red / green. That is, there is a problem that color reproducibility is low.

  On the other hand, the imaging device 1 in the present embodiment includes a transparent filter 2W, a yellow filter 2Y, a red filter 2R, and a correction filter 2Blk instead of the three primary colors of red, green, and blue color filters.

  Therefore, the spectral characteristics of the image sensor 1 in the present embodiment are the sensitivity of the light receiving element and the transmission of the transparent filter 2W, yellow filter 2Y, red filter 2R, and correction filter 2Blk disposed on the light incident side of the light receiving element. It is considered equivalent to the product value multiplied by the rate.

  The transmittances of the transparent filter 2W, the yellow filter 2Y, and the red filter 2R are higher than those of the blue color filter and the green color filter.

  Therefore, when observed by the incident light receiving element 3W, the yellow light receiving element 3Y, the red light receiving element 3R, and the correction light receiving element 3Blk via the transparent filter 2W, the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk, the observed data value The observation data values Db, Dg, and HDr calculated based on Dw, Dy, Dr, and Dblk can be said to be observation results obtained with high transmittance.

  In particular, the blue observation data value Db is equivalent to that observed at a high light intensity, the blue / green sensitivity ratio can be increased, and the color reproducibility can be improved.

  Furthermore, in the present embodiment, the blue observation data value Db, the green observation data value Dg, and the corrected red observation data value HDr can be obtained by performing a simple operation of subtraction once.

  Therefore, the calculation can be simplified as compared with an image pickup device using a conventional complementary color filter, and a vivid color close to the primary color can be expressed.

  Next, “removing the infrared cut filter” will be described.

  In the conventional imaging device, the light receiving device observes light in the infrared region, and the accuracy of the observation result may be reduced.

  On the other hand, in the present embodiment, the observation data value of the yellow light receiving element 3Y is calculated from the observation data value Dw of the incident light receiving element 3W, the observation data value Dy of the yellow light receiving element 3Y, and the observation data value Dr of the red light receiving element 3R. In order to subtract the observed data value Dr of Dy / red light receiving element 3R and the observed data value Dblk of corrected light receiving element 3Blk, the observation results in the infrared region of each light receiving element are canceled (removed), and the influence of the observation results in the infrared region is affected. The reduced blue observation data value Db, green observation data value Dg, and corrected red observation data value HDr can be obtained. That is, the infrared cut filter can be deleted from the configuration of the image sensor, and the thickness can be reduced.

  Next, “noise due to dark current” will be described.

  As shown in FIG. 6C, the light receiving element generates a slight current even when light is not incident. The current that flows from the light receiving element even though such light is not incident is called dark current, and causes noise. Since the conventional color filters of the three primary colors of red, green, and blue transmit light in a predetermined wavelength range in terms of spectral characteristics, there are also wavelength ranges where light is blocked.

  However, the light receiving element generates dark current even in a wavelength region where light is blocked.

  For this reason, the observation result of the conventional image sensor includes noise due to dark current in addition to the observation result of light in the wavelength range where light is transmitted, and this noise may reduce the color reproducibility. .

  On the other hand, as described above, the imaging element 1 according to the present embodiment has the observation data value Dw of the incident light receiving element 3W, the observation data value Dy of the yellow light receiving element 3Y, and the observation data value Dr of the red light receiving element 3R. Therefore, the observed data value Dy of the yellow light receiving element 3Y, the observed data value Dr of the red light receiving element 3R, and the observed data value Dblk of the corrected light receiving element 3Blk are subtracted, so that the dark current value is canceled out. Thereby, noise can be removed from the observation result, so that color reproducibility can be improved.

  Next, “spectral float” will be described.

  As shown in FIG. 6C, in the spectral transmittance of the conventional red, green, and blue color filters, the transmittance at the bottom of the spectral curve of the red and blue color filters is as low as several percent, The transmittance at the bottom of the spectral curve of the color filter is as high as about 10%. Thus, it is said that the float of a spectrum is large that the transmittance | permeability of a skirt part is high.

  In the conventional imaging device, the base of the spectral curve of the green color filter exists in the red and blue wavelength regions, and the spectrum of the green base is large. For this reason, red and blue are mixed with the observation result of green, and there is a problem that the reproducibility of green deteriorates.

  On the other hand, in the imaging device 1 according to the present embodiment, as described above, the observation data value Dw of the incident light receiving element 3W, the observation data value Dy of the yellow light receiving element 3Y, and the observation data value of the red light receiving element 3R. From Dr, the observation data value Dy of the yellow light receiving element 3Y, the observation data value Dr of the red light receiving element 3R, and the observation data value Dblk of the correction light receiving element 3Blk are subtracted. Therefore, the float of the spectrum can be reduced and the color reproducibility can be improved.

  Next, the “infrared cut function of the correction filter 2Blk” will be described.

  FIG. 7 is a graph showing an example of the spectral characteristics of the correction filter 2Blk.

  The transmittance of the correction filter 2Blk is substantially the same level (same or approximate) as the transmittance of the red filter 2R in FIG. 4 on the longer wavelength side than the visible light wavelength region.

  FIG. 7 shows a correction filter 2Blk formed by mixing and dispersing a violet pigment (for example, CI PigmentViolet23) and a pigment used for forming the red filter 2R and using an acrylic resin film having a thickness of 1.4 μm. Represents the spectral characteristics.

  The correction filter 2Blk may be a combination in which a yellow pigment used for a yellow filter is mixed with violet, or a combination in which a red pigment is further added thereto.

  By subtracting the observation data value Dblk observed by the correction light receiving element 3Blk from the observation data value Dr observed by the red light receiving element 3R, the observation result in the infrared region from the observation data value Dr observed by the red light receiving element 3R Can be deleted. Therefore, the correction filter 2Blk serves as an infrared cut filter for the red observation data value.

  The correction filter 2Blk shown in FIG. 7 is low in transmittance around 600 nm to 650 nm (effective transmittance as an infrared cut filter), unlike the general absorption type infrared cut filter shown in FIG. Therefore, it is possible to further improve the color rendering properties of red obtained after calculation (subtraction).

  In the present embodiment, the transmittance of the correction filter 2Blk is a difference within 5% from the transmittance of the red color filter shown in FIG. 37 in the light wavelength range of approximately 400 nm to 550 nm and in the wavelength range of 750 nm and later. To be.

  As a result, it is possible to obtain a corrected red observation data value HDr that is not affected by infrared rays or other colors, and the red color reproducibility is improved.

  Further, the transmittance of the correction filter 2Blk maintains a low value from approximately 400 nm to 630 nm when the wavelength changes from 400 nm to 800 nm. And it rises rapidly between 630 nm and 750 nm, and when it exceeds 750 nm, a high value is maintained.

  Supplementing this point, in the conventional absorption-type infrared cut filter, the wavelength at which the transmittance becomes a half value (50%) is about 630 nm. In the conventional infrared cut filter of an inorganic multilayer film, the wavelength at which the transmittance becomes half value is approximately 700 nm. In addition, in the correction filter by optical superimposition of violet and red, the wavelength at which the transmittance becomes half value is approximately between 650 nm and 660 nm. In addition, in the correction by optical superimposition of cyan and red, the wavelength at which the transmittance becomes half value is between about 740 nm and 750 nm.

  From the above viewpoint, in the correction filter 2Blk, it is desirable that the wavelength of the point P at which the transmission value becomes a half value is included in the wavelength region between 630 nm and 750 nm.

  In the imaging device 1 according to the present embodiment, the corrected red observation data value HDr is obtained by (red observation data value Dr) − (correction observation data value Dblk). Therefore, by making the light transmittance of the correction filter 2Blk as shown in FIG. 7, the corrected red observation data value HDr can be prevented from being influenced by infrared rays and other colors of light. In addition, it is possible to obtain the image sensor 1 having high red sensitivity and good red color reproducibility.

  In the present embodiment, as described above, the correction filter 2Blk may be configured by optical superimposition of two colors of violet and red, for example, and may be configured by optical superimposition of two colors of cyan and red. Also good.

  By forming the correction filter 2Blk by combining these two colors, the wavelength position at which the light transmittance of the correction filter 2Blk becomes half value can be adjusted by the ratio of the color material, and the corrected red color Color adjustment can be performed on the observed data value HDr.

  Further, color adjustment (for example, gray level adjustment) in the visible light wavelength range of the correction filter 2Blk, the rise of the transmission curve in the near-infrared transmission spectrum of 700 nm or 700 nm or later of the correction filter 2Blk, and the transmittance at half value. The wavelength position to be adjusted may be adjusted by adding other colorants or organic pigments of other colors, for example, organic pigments such as violet, blue, and green.

  Next, the “ultraviolet absorber and infrared absorber” will be described.

  Photosensitive elements such as CMOS and CCD have some sensitivity even in the ultraviolet region that humans do not feel.

  Therefore, it is desirable that the transparent filter 2W according to the present embodiment does not transmit light of 400 nm or less and allows light having a wavelength of 400 nm or less to pass through without being absorbed. Therefore, an ultraviolet absorber or a photoinitiator or curing agent used for curing the resin may be attached to the transparent filter 2W according to this embodiment, and an ultraviolet absorbing function may be added to the transparent filter 2W.

  As the ultraviolet absorber, for example, benzotriazole compounds, benzophenone compounds, salicylic acid chemicals, and coumarin compounds can be used. Further, for example, a light stabilizer such as a hindered amine compound, a quencher or the like may be added to the ultraviolet absorber.

  Furthermore, the polymer, monomer, or curing agent of the resin used for forming the transparent filter 2W may be pendant with a functional group having an ultraviolet absorption function, or may be polymerized with a group that can be incorporated into the polymer. For example, quinones or anthracene may be introduced into the polymer, or a monomer having an ultraviolet absorbing group may be added. The pendant refers to incorporation into a resin molecular chain in the form of a reactive absorbent or the like.

  Moreover, you may add an infrared absorptive compound and an infrared absorber to resin which comprises the transparent filter 2W. Specifically, it can be added to the resin constituting the transparent filter 2W by a pendant method.

  In the image pickup device 1 according to the present embodiment described above, it is possible to obtain the same effect as the case of having a high-transmission red, green, and blue filter. Blue observation accuracy can be improved.

  In the imaging device 1 according to the present embodiment, the observation result of the light in the infrared region that is not the human visible region can be deleted, and the photographing result close to human vision can be obtained.

  Further, in the imaging device 1 according to this embodiment, unlike the case of using a general absorption type infrared cut filter having the transmission characteristics shown in FIG. 36, the absorption of light in the wavelength region of 550 nm to 650 nm is reduced. Therefore, the color rendering properties of red can be improved.

  In this embodiment, the infrared absorption function is realized by observing infrared light at the correction pixel of the image sensor and subtracting the correction pixel observation result from the red pixel observation result. Yes.

  In addition, for other colors (blue and green), observation results in which the infrared region is drawn are obtained. As a result, the infrared absorption type infrared cut filter provided in the optical system of the conventional camera module can be omitted, and the camera can be thinned.

  In addition, since transparent, yellow, and red color filters are used instead of red, green, and blue color filters, even if the image sensor is miniaturized using a correction filter, the decrease in sensitivity due to a decrease in the amount of incident light is suppressed. Can do.

<Second Embodiment>
In the present embodiment, a modified example of the image sensor according to the first embodiment will be described.

  Note that the imaging element according to the present embodiment has a configuration in which the transparent filter 2W and the resin layer 7 are integrated in the imaging element 1 according to the first embodiment.

  FIG. 8 is a plan view illustrating an example of an arrangement state of filters in the image sensor according to the present embodiment. In FIG. 8, an example of the state of the filter layer portion viewed from the light incident side is shown.

  FIG. 9 is a cross-sectional view illustrating an example of an image sensor according to the present embodiment. In FIG. 9, the II-II 'cross section of FIG. 8 is shown.

  The transparent filter 10W of the image sensor 9 according to the present embodiment corresponds to the transparent filter 2W and the resin layer 7 of the first embodiment. Specifically, a part of the transparent filter 10W is placed at the position of the transparent filter 2W according to the first embodiment.

  The other part of the transparent filter 10W covers the light incident side surfaces of the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk. That is, the transparent filter 10W according to the present embodiment has a configuration in which the transparent filter 2W according to the first embodiment and the resin layer 7 are integrated, and also serves as a transparent flattening layer.

  The image sensor 9 includes a transparent filter 10W, a yellow filter 2Y, a red filter 2R, and a correction filter 2Blk.

  In FIG. 9, the correction filter 2Blk is formed of a single layer of a colored resin obtained by mixing a violet pigment and a red pigment.

  The incident light receiving element 3W, the yellow light receiving element 3Y, the red light receiving element 3R, and the correction light receiving element 3Blk receive light that has passed through the transparent filter 10W, the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk, respectively, and convert them into electrical signals. To do.

  Similar to the first embodiment, the image sensor 9 performs an operation (subtraction) on the basis of the observation data values Dw, Dy, Dr, and Dblk by the respective light receiving elements, and performs the three primary colors of blue, green, and corrected red. Observation data values Db, Dg, and HDr are obtained.

  That is, the image pickup device 9 is assumed to have a blue filter, a green filter, and a red filter in appearance (virtually) by performing calculation (subtraction) based on the observation data value by each light receiving element. Is possible.

  An example of the spectral transmittance of wavelengths 400 nm to 800 nm for the apparent blue filter, green filter, and red filter obtained by the calculation of the image sensor 9 is the same as in FIG.

  The apparent transmittance of the blue filter and the green filter of the image pickup device 9 is characterized in that the transmittance is higher than that of the conventional blue color filter and green color filter in the wavelength range of each color.

  In the present embodiment described above, the light incident side surfaces of the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk are covered with the transparent filter 10W, and the transparent filter 10W and the transparent flattening layer are integrated.

  Thereby, the formation process of the transparent filter 10W and the transparent planarization layer can be integrated, and in the formation of the filter, it is not necessary to provide the pattern formation process of the transparent filter independently, and the manufacturing process of the imaging device 9 can be performed. It can be simplified.

  That is, in the present embodiment, after forming the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk, the transparent filter 10W that is a transparent flattening layer is formed so as to cover these filters.

  In the present embodiment, a part of the transparent filter 10W, which is a transparent flattening layer, is disposed in the portion where the transparent filter 2W is formed in the first embodiment, and the transparent filter 10W serves as a transparent flattening layer. Fulfill.

  Thereby, in this embodiment, the process of forming a transparent filter uniquely by a technique such as photolithography, for example, can be omitted, and a filter for four colors can be configured with the effort of forming a filter for three colors. The filter forming process can be reduced.

<Third Embodiment>
In the present embodiment, modifications of the image sensor according to the first and second embodiments will be described. Note that the imaging element according to the present embodiment includes the transparent filter 10 </ b> W and the microlens 8 in an integrated configuration in the imaging element 9 according to the second embodiment.

  FIG. 10 is a cross-sectional view illustrating an example of an image sensor according to the present embodiment.

  The image sensor 11 according to the present embodiment includes a transparent filter 12W in which the microlens 8 of the image sensor 9 according to the second embodiment and the transparent filter 10W are integrated. That is, the transparent filter 12W has a function of improving the light condensing property to the incident light receiving element 3W, the yellow light receiving element 3Y, the red light receiving element 3R, and the correction light receiving element 3Blk.

  Below, the manufacturing process of this image pick-up element 11 is demonstrated using FIGS.

  First, the planarizing layer 6 made of a transparent resin is applied and formed on the semiconductor substrate 5 on which the incident light receiving element 3W, the yellow light receiving element 3Y, the red light receiving element 3R, and the correction light receiving element 3Blk are formed (FIG. 11).

  In forming a color filter made of a photosensitive resin, since ultraviolet rays are used for pattern exposure to the photosensitive resin, an ultraviolet absorber may be added to the planarizing layer 6 in order to prevent halation during pattern exposure. Good.

  Next, a correction filter 2Blk (not shown) in which a yellow filter 2Y, a red filter 2R (not shown), and violet and red are optically superimposed is formed on the planarizing layer 6 in this order by photolithography. (FIG. 12).

  The film thickness of each filter is formed to 1.4 μm, and the pixel pitch of each filter is formed to 2.6 μm. The average film thickness of the planarizing layer 6 is formed to 0.1 μm. However, the planarization layer 6 may be omitted in order to make the imaging device 11 thinner.

  Subsequently, a thermosetting acrylic resin containing 2% of a coumarin ultraviolet absorber is applied to the semiconductor substrate 5 on which the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk are formed with an average film thickness of 2 μm. Then, heating is performed at 180 ° C. for 3 minutes, the applied resin layer is cured, and a flattened transparent filter 12W is formed (FIG. 13).

  Further, on the transparent filter 12W, a photosensitive phenol resin 13 having a thermal reflow property (a property of being fluidized and rounded by heat treatment) and capable of an alkaline phenomenon is applied.

  Next, the photosensitive phenol resin 13 is formed into a predetermined pattern (for example, a rectangular pattern) by photolithography. Then, heating is performed at 200 ° C. to fluidize the photosensitive phenol resin 13 having a predetermined pattern to form a hemispherical lens matrix 13a having a thickness of about 0.6 μm (FIG. 14).

  Subsequently, anisotropic etching is performed on the transparent filter 12W in a dry etching apparatus (FIG. 15). This etching eliminates the lens matrix 13a, but this lens matrix 13a serves as a mask for the transparent filter 12W, and the hemispherical shape of the lens matrix 13a is transferred to the transparent filter 12W. Thereby, it is possible to obtain the imaging device 11 that functions as a microlens and includes the transparent filter 12 </ b> W provided on each filter.

  As described above, the transparent filter 12W according to the present embodiment is integrated with the microlens. Thereby, the image pick-up element 11 can be made thin.

  In the present embodiment, the transparent filter 12W serving as a transparent flattening layer has a microlens shape, but the transparent filter 12W serving as a transparent flattening layer can be used without forming a microlens. Good. In this case, after forming the transparent filter 12W in the third step of FIG. 13, the imaging element can be obtained without performing the steps after the formation of the photosensitive phenol resin 13.

  Further, as described above, it is preferable that an ultraviolet absorber is added to the planarizing layer 6 in order to prevent halation during pattern exposure of the photosensitive resin. Furthermore, it is preferable to add an ultraviolet absorber to the transparent filter 12W in order to prevent generation of noise due to ultraviolet rays based on the sensitivity of the light receiving element in the ultraviolet region. As the ultraviolet absorber, fine particles made of a metal oxide such as cerium oxide or titanium oxide can be used.

  However, as described above, when the lens shape is transferred to the transparent filter 12W, and the transparent filter 12W is a transfer type microlens, when an ultraviolet absorber is not added, an inorganic material is contained in the resin of the transfer lens. May become an optical foreign matter and light may be blocked. In this case, a black portion (black defect) is generated in the image obtained by the image sensor 11.

  Therefore, it is preferable to use a dye-based ultraviolet absorber. For example, benzotriazole, benzophenone, triazine, salicylate, coumarin, xanthene, and methoxycinnamic acid organic compounds are used as the ultraviolet absorber.

  In each of the above embodiments, yellow may be a common color of red and correction color. That is, except for the transparent portion, yellow may be included in common in the red portion and the correction color portion, and may be used as a subtracting color for other color portions except for the transparent portion. In this case, for example, the yellow filter 2Y is formed at the yellow formation position with a yellow resin, and at the same time, the yellow filter 2Y is formed at the red formation position and the correction color formation position. Then, the red filter 2R is formed at the red formation position, and the correction filter 2Blk is stacked at the correction color formation position to form an image sensor.

<Fourth Embodiment>
In this embodiment, a reflection suppression filter that suppresses reflection, diffusion, and wraparound of light other than light incident on the light receiving element out of incident light is provided on the incident light incident side of the substrate and incident light on the light receiving element. An image sensor provided in other areas excluding the area where light is incident will be described.

  FIG. 16 is a plan view showing a first example of the arrangement position of the light shielding film of the image sensor according to the present embodiment.

  The imaging element 17 shown in FIG. 16 is provided with a light-shielding film 19 that suppresses reflection and transmission of light on the outer peripheral portion of the effective pixel portion 18 where the spectral filter is provided, on the light incident side of the light receiving element. The image sensor 17 has an electrode portion 20 made of aluminum or the like for electrical connection with the outside. The light shielding film 19 is not formed on the electrode portion 20.

  The light-shielding film 19 can be the correction filter described in the above embodiments.

  Arranging the light shielding film 19 on the outer peripheral portion of the effective pixel portion 18 of the image sensor 17 can prevent the observation result of the image sensor 17 from being affected by noise, and is effective in improving the image quality. . In particular, by using the above-described various correction filters as the light shielding film 19, it is possible to cut light having a visible light wavelength and reduce stray light around the image sensor 17.

  FIG. 17 is a cross-sectional view illustrating a second example of the arrangement position of the light shielding film of the image sensor according to the present embodiment.

  The imaging element 14 shown in FIG. 17 has the same configuration as that of the imaging element 1 according to the first embodiment, but the incident light receiving element 3 </ b> W / yellow light receiving sac among the light incident side surfaces of the semiconductor substrate 5. The light-shielding film 15 and the film 16 are stacked in a region other than a region where light is taken into the 3Y / red light receiving element 3R / corrected light receiving element 3Blk.

  As the light shielding film 15, for example, a correction filter 2Blk can be used. That is, the light shielding film 15 can be formed with the same material and configuration as the correction filter 2Blk by the same method as the method of forming the correction filter 2Blk.

  The imaging element 14 is provided with a light shielding film 15 (correction filter 2W) having transmission suppression characteristics in the visible light wavelength region on the semiconductor substrate 5 and outside the opening of the light receiving element.

  Supplementally, in a conventional image sensor, light incident on a portion other than the light receiving element may stray in the image sensor and become stray light. This stray light becomes noise when entering the light receiving element. Further, when unnecessary light is incident on the peripheral area of the light receiving element, it causes noise. However, in the present embodiment, a light shielding film 15 having transmission suppression characteristics in the visible light wavelength region is disposed around the effective opening of the light receiving element and part of the semiconductor substrate 5 (for example, the outer periphery of the semiconductor substrate 5). Yes. For this reason, the light incident on the other portions except the light receiving element is absorbed by the light shielding film 15.

  Thereby, noise due to stray light and unnecessary light can be reduced, and the image quality obtained by the image sensor 14 can be improved. In particular, when the correction filter 2W is used as the light shielding film 15, light in the visible light wavelength region can be cut, stray light generated around the imaging element 14 can be reduced, and noise generation from the periphery of the light receiving element can be reduced. .

  When the correction filter 2 </ b> W is used as the light shielding film 15, infrared light and ultraviolet light pass through the light shielding film 15. Therefore, in the present embodiment, a light shielding film 15 using a black pigment such as carbon black is disposed on a portion of the semiconductor substrate 5 that is not an effective opening of the light receiving element, and the light shielding film 15 has an infrared cut function. However, when the infrared ray and ultraviolet ray absorbing performance of the light shielding film 15 is insufficient, a film 16 that absorbs infrared rays and ultraviolet rays is further laminated on the light shielding film 15. As a result, it is possible to prevent infrared rays and ultraviolet rays incident on a portion that is not a light receiving element from straying, becoming stray light, and generating noise. If the film 16 is made of a transparent resin used for forming the microlens 8 and a resin obtained by adding an infrared absorber and an ultraviolet absorber, the material cost can be reduced.

  In the present embodiment, the case where the image pickup device 1 according to the first embodiment includes the light shielding film 15 and the film 16 is described as an example. However, the image pickup device according to another embodiment is described as an example. On the other hand, the light shielding film 15 and the film 16 may be provided. Further, only the light shielding film 15 may be provided for the imaging device.

<Fifth Embodiment>
In the present embodiment, when manufacturing the image sensor 11S, the correction filter 2Blk is formed by dry etching, and the yellow filter 2Y and the red filter 2R are formed by photolithography.

  FIG. 18 is a front view illustrating an example of a filter arrangement state in the image sensor 11S according to the present embodiment.

  FIG. 19 is a cross-sectional view showing an example of the image sensor 11S according to the present embodiment. FIG. 19A shows a III-III ′ cross section of FIG. 18, and FIG. 19B shows a IV-IV ′ cross section of FIG. 18.

  The image sensor 11S is different from the first to third embodiments in the arrangement of the red filter 2R and the correction filter 2Blk, but is not different in performance. That is, the spectral transmittance characteristics of the color filter included in the image sensor 11S are the same as those shown in FIG. In addition, the spectral transmittance characteristics of the apparent blue filter, green filter, and red filter after color calculation (subtraction) processing using the color filters having these spectral characteristics are the same as those shown in FIG. It is.

  Next, a manufacturing method of the image sensor 11S according to the present embodiment will be described with reference to FIGS.

  First, the planarizing layer 6 made of a transparent resin is formed on the semiconductor substrate 5 on which the incident light receiving element 3W, the yellow light receiving element 3Y, the red light receiving element 3R, and the correction light receiving element 3Blk are formed (FIG. 20A). B)). Specifically, a coating liquid mainly composed of an acrylic resin is spin-coated at a rotational speed of 2000 rpm on a semiconductor substrate on which light receiving elements are two-dimensionally arranged. Then, a planarization layer 6 having a thickness of 0.2 μm is formed by performing a heat treatment at 200 ° C. to form a hard film. In addition, what added the coumarin type ultraviolet absorber whose solid ratio is about 3% can be used for the coating liquid of an acrylic resin.

  Next, a black resin layer BL that is a correction filter having the highest color material content ratio among the color filters of the transparent filter 12W, the red filter 2R, the yellow filter 2Y, and the correction filter (black) 2Blk is formed. (FIG. 20C). Specifically, an organic pigment (mixture of C.I. Pigment Violet 23 and C.I. Pigment Red177, C.I. Pigment Red48: 1, C.I. Pigment Yellow139) is dispersed and mixed in a thermosetting acrylic resin to form a hard film. Thereby, a black resin layer BL having a thickness of about 1.6 μm is formed. The black resin layer BL having a color material (organic pigment) solid ratio of about 58% can be used.

  Next, a photoresist layer PL is formed over the black resin layer BL (FIG. 21A). The photoresist layer PL is alkali-soluble and photosensitive, and is formed to a thickness of 1.2 μm.

  Next, the photoresist layer PL is patterned to expose the black resin layer BL at a site to be the correction filter 2Blk. Specifically, pattern exposure is performed on the photoresist layer PL by using a pattern exposure mask M (FIG. 21B).

  Subsequently, development is performed by dissolving a portion of the photoresist layer PL other than the portion irradiated with light with an alkaline solution, and if necessary, hardening is performed. Thereby, the black resin layer BL other than the portion to be the correction filter 2Blk can be exposed (FIG. 21C).

  Next, the photoresist layer PL and the black resin layer BL exposed from the photoresist layer PL are dry-etched. As a result, the black resin layer BL excluding the portion to be the correction filter 2Blk is removed, and the photoresist layer PL is also removed, thereby forming the correction filter 2Blk (FIG. 21D). As shown in FIG. 4, the correction filter 2Blk exhibits a low transmittance of 10% or less in the light wavelength range of 400 nm to 600 nm, and a high transmittance of 90% or more in the wavelength range longer than 750 nm. It is.

  Next, after the formation of the correction filter 2Blk, a yellow filter 2Y and a red filter 2R other than the correction filter 2Blk are formed in a region different from the correction filter 2Blk on the semiconductor substrate (a region indicated by the IV-IV ′ cross section in FIG. 18). It forms by the photolithographic method (FIG. 22).

  Specifically, two types of color resists (yellow and red), which are mixed with a photosensitive acrylic resin that can be exposed and developed, are used for pattern exposure, development with a developer such as an alkaline solution, and hardening in photolithography. The yellow filter 2Y and the red filter 2R having a film thickness of about 1.2 μm are formed by the method. An organic pigment C.I. Pigment Yellow 150 can be used as the color material of the yellow filter 2Y. The yellow filter 2Y has a solid ratio of the color material (organic pigment) of about 30%. In addition, a mixed pigment of C.I. PigmentRed177, C.I. Pigment Red48: 1 and C.I. Pigment Yellow139 can be used for the color material of the red filter 2R. In the red filter 2R, the solid ratio of the color material (organic pigment) is about 45%.

  Next, a transparent resin layer is spin-coated on the semiconductor substrate 5 so as to cover the correction filter 2Blk, the yellow filter 2Y, and the red filter 2R. Then, the transparent resin layer is thermally cured to form the planarization layer 12 including the transparent filter 12W (FIG. 23A). The flattening layer 12 is formed of a thermosetting acrylic resin coating liquid which is made of substantially the same material as the flattening layer 6 and has a high solid ratio for thick films. The planarizing film 12 has a thickness of about 2 μm.

  Next, a lens matrix 13a is formed on the planarizing layer 12 (FIG. 23B). Here, the lens matrix 13a is formed of a photosensitive phenol resin that can be exposed and developed. The photosensitive phenol resin is a resin having a thermal reflow property, that is, a characteristic of melting by heat treatment and rounding into a lens shape by surface tension.

  Next, anisotropic dry etching is performed using the lens matrix 13a as a mask to transfer the shape of the lens matrix 13a to the planarization layer 12 to form a microlens (FIG. 23C). That is, the microlens 8 and the transparent filter 12W are formed simultaneously.

  Note that the dry etching amount (etching depth) is about 1 μm, and the correction filter 2Blk is 0.4 μm deeper in the film thickness direction so that a part of the correction filter 2Blk substantially serves as the microlens 8. Etch.

  Further, the yellow filter 2Y and the red filter 2R are substantially 1.2 μm thick as etching depths to the surfaces thereof.

  The image sensor 11S can be manufactured by the method described above.

  Here, according to the present embodiment, a step of forming a high ratio color filter having a high color material content ratio among the color filters by dry etching and a low ratio color filter other than the high ratio color filter are formed by a photolithography method. Therefore, the colored resin residue can be removed as compared with the case where the high ratio color filter is formed by a photolithography method. Moreover, it can form without destroying the shape of a high ratio color filter.

  Supplementally, when a filter is formed only by a photolithography method, as shown in FIG. 24A, the organic pigment remains and a residue is easily generated, and the shape of the filter is easily broken. For example, when 2 μm square patterning is performed, unevenness is generated at the edge, and it is difficult to form a square shape. On the other hand, according to dry etching, as shown in FIG. 24B, the residue can be eliminated, and the filter can be formed into a desired square shape without breaking the shape. More specifically, an SEM photograph of a 2 μm square correction filter 2Blk (FIG. 25A) formed by dry etching and a 2 μm square correction filter 2Blk formed by photolithography (FIG. 25B) (FIG. 25B). When the electron micrograph is compared, the side of the correction filter formed by the photolithography method has an uneven shape. In addition, when the color filter becomes, for example, 1.8 μm square or less and becomes a fine pattern, the photolithography method may cause the color filter to peel off during development after pattern exposure, making the pattern formation impossible. On the other hand, such a problem does not occur in dry etching, and a fine color filter can be formed with a good shape.

  However, when manufacturing color filters, dry etching is often more laborious than photolithography, and forming all filters by dry etching causes problems such as increased manufacturing costs. . Therefore, the correction filter 2Blk having a high organic pigment content ratio is formed by dry etching, and the yellow filter 2Y and the red filter 2R are formed by a photolithography method, so that a residue can be eliminated and a color filter having a uniform shape can be easily obtained. Can be formed.

  As a result, a plurality of light receiving elements 3W, 3Y, 3R, and 3Blk provided on the semiconductor substrate 5 and a plurality of types of color filters 2W, 2Y, 2R, and 2Blk individually formed on the light receiving elements are provided. It is possible to manufacture the image pickup device 11S that has a good color balance and color reproducibility and has improved image quality.

  In addition, according to the present embodiment, the imaging device 11S including the correction filter 2Blk having a transmittance of 10% or less in the wavelength region of 400 nm to 600 nm and a transmittance of 90% or more in the wavelength region of 750 nm to 1100 nm. Can be manufactured.

  Furthermore, it is possible to manufacture the image sensor 11S including the transparent filter 12W having a transmittance of 90% or more in the wavelength range of 400 nm to 1100 nm.

  Further, it is possible to manufacture the image sensor 11S including a transparent filter that absorbs ultraviolet rays in a wavelength region shorter than 400 nm.

  Moreover, it has the 1st wavelength range which shows the transmittance | permeability of 10% or less in the wavelength range of 400 nm-600 nm, and is 90% or more in the wavelength range longer than the said 1st wavelength range and 450 nm-1100 nm. An image sensor 11S including a color filter (yellow filter and red filter) having a wavelength range that is transmittance can be manufactured.

  Furthermore, the yellow filter 2Y used for extracting the yellow component of light, the red filter 2R used for extracting the red component of light, and transmission suppression characteristics in the visible light wavelength region, The image sensor 11S including the correction filter 2Blk having transmission characteristics on the longer wavelength side can be manufactured.

  That is, according to the present embodiment, it is possible to provide an image sensor 11S having RGB primary color filters exhibiting high transmittance particularly in blue (B) and green (G). Further, it is possible to provide the image pickup device 11S in which the infrared cut filter that is indispensable for the optical sensor is omitted by the correction filter 2Blk. Thereby, an optical system such as a camera can be made thinner by the thickness required for the infrared cut filter.

  In addition, a pixel having a high pigment ratio, a large film thickness, and a problem such as a residue (residual organic pigment residue) or pixel peeling can be processed with good shape while eliminating the residue by a dry etching technique. Thereby, an improvement in image quality can be obtained.

<Sixth Embodiment>
In the present embodiment, the correction filter 2Blk is formed by stacking the violet filter 2V and the red filter 2R when the imaging device 11T is manufactured.

  That is, in this embodiment, the correction filter 2Blk is not formed by a color material obtained by mixing a violet color material and a red color material, but the optical filter is formed by stacking the violet filter 2V and the red filter 2R. Are superimposed on each other to form the correction filter 2Blk.

  FIG. 26 is a front view illustrating an example of an arrangement state of filters in the image sensor 11T according to the present embodiment.

  FIG. 27 is a cross-sectional view showing an example of the image sensor 11T according to the present embodiment. 27A shows the V-V ′ cross section of FIG. 26, and FIG. 27B shows the VI-VI ′ cross section of FIG. 26.

  The image pickup device 11T is different from the first to third embodiments in the arrangement state of the red filter 2R and the correction filter 2Blk, but is not different in performance. That is, the spectral characteristics of the image sensor 11T are the same as those shown in FIG. In addition, the spectral transmittance characteristics of the apparent blue filter, green filter, and red filter after color calculation (subtraction) processing using the color filters having these spectral characteristics are the same as those shown in FIG. It is.

  Next, a manufacturing method of the image sensor 11T according to the present embodiment will be described with reference to FIGS.

  First, the planarizing layer 6 made of a transparent resin is formed on the semiconductor substrate 5 on which the incident light receiving element 3W, the yellow light receiving element 3Y, the red light receiving element 3R, and the correction light receiving element 3Blk are formed (FIG. 28A, (B)). Specifically, a coating solution containing acrylic resin as a main component is spin-coated at a rotational speed of 2000 rpm on a semiconductor substrate on which light receiving elements are two-dimensionally arranged. Then, a planarization layer 6 having a thickness of 0.2 μm is formed by performing a heat treatment at 200 ° C. to form a hard film. In addition, what added the coumarin type | system | group ultraviolet absorber whose solid ratio is about 5% can be used for the coating liquid of an acrylic resin.

  Subsequently, a red resin layer RL that becomes the red filter 2R having the highest color material content ratio among the transparent filter 12W, the red filter 2R, and the yellow filter 2Y is formed. (FIG. 28C). Specifically, an organic pigment (mixture of C.I. Pigment Red177, C.I. Pigment Red48: 1, C.I. Pigment Yellow139) is dispersed and mixed in a thermosetting acrylic resin to form a film. Thereby, a red resin layer RL having a thickness of about 1 μm is formed.

  Next, a photoresist layer PL is formed over the red resin layer RL (FIG. 29A). The photoresist layer PL is alkali-soluble and photosensitive, and is formed to a thickness of 0.8 μm.

  Next, the photoresist layer PL is patterned to expose the red resin layer RL in the pattern of the red filter 2R and the correction filter 2Blk.

  Specifically, pattern exposure is performed on the photoresist layer PL at a portion where the red filter 2R and the correction filter 2Blk are to be formed using the pattern exposure mask M (FIG. 29B). Then, development is performed in which a portion of the photoresist layer PL other than the portion irradiated with light is dissolved in an alkaline solution. Thereby, the red resin layer RL excluding the portions to be the red filter 2R and the correction filter 2Blk can be exposed (FIG. 29C).

  Next, the red resin layer RL exposed from the pattern of the photoresist layer PL is dry-etched (FIG. 29D). As a result, the red resin layer RL excluding the portions to be the red filter 2R and the correction filter 2Blk is removed, and the photoresist layer PL is also removed, so that the red filter 2R and the correction filter 2Blk are formed. (FIG. 29D). In the red filter 2R, the concentration of the color material (organic pigment) is about 45% in terms of the weight ratio after film hardening.

  Next, after the formation of the red filter 2R, the yellow filter 2Y is formed by photolithography in a region different from the red filter 2R on the semiconductor substrate 5 (the position shown in the VI-VI ′ cross section in FIG. 26) (FIG. 30). ).

  Specifically, after applying a color resist (yellow) mixed with a color material to a photosensitive acrylic resin that can be exposed and developed, a yellow filter having a film thickness of about 1 μm is obtained by photolithography techniques such as pattern exposure and development with an alkaline solution. 2Y is formed. An organic pigment C.I. Pigment Yellow 150 can be used as the color material of the yellow filter 2Y. The yellow filter 2Y has a solid ratio of the color material (organic pigment) of about 30%.

  Next, a purple resin layer VL is formed so as to cover the yellow filter 2Y and the red filter 2R (FIG. 31A). Subsequently, a violet filter 2V is formed on a part of the red filter 2R from the purple resin layer VL by using a photolithography method that performs pattern exposure / development and the like (FIGS. 31B and 31C). Thus, the violet filter 2V and the red filter 2R are optically superimposed to form a correction filter 2Blk.

  The purple resin layer VL can be formed of C.I. Pigment Violet 23 having a pigment concentration of 40%.

  Next, a transparent resin layer is spin-coated on the semiconductor substrate 5 so as to cover the correction filter 2Blk (integrated of the violet filter 2V and the red filter 2R), the yellow filter 2Y, and the red filter 2R. . Then, the transparent resin layer is thermally cured to form the planarizing layer 12 including the transparent filter 12W (FIG. 32A). The flattening layer 12 is made of substantially the same material as the flattening layer 6 and is formed of a thermosetting acrylic resin coating liquid having a high solid ratio for thick films. The planarizing film 12 has a thickness of about 2 μm.

  Next, a lens matrix 13a is formed on the planarizing layer 12 (FIG. 32B). Here, the lens matrix 13a is formed of a photosensitive phenol resin that can be exposed and developed. The photosensitive phenol resin is a resin that has thermal reflow properties and melts by heat treatment and rounds into a lens shape by surface tension.

  Subsequently, anisotropic dry etching is performed using the lens matrix 13a as a mask to transfer the shape of the lens matrix 13a to the planarizing layer 12 to form the microlens 8 (FIG. 32C). . Here, the microlens 8 and the transparent filter 12W are formed simultaneously.

  The dry etching amount (etching depth) is about 1 μm, and the correction filter 2Blk has a film thickness such that the violet filter 2V, which is substantially part of the correction filter 2Blk, plays the role of the microlens 8. Etch deeply 0.4 μm in the direction.

  The imaging element 11T can be manufactured by the manufacturing method described above.

  Here, according to the present embodiment, the step of forming the red filter 2R having a high color material content ratio among the red filter 2R and the yellow filter 2Y by dry etching and the step of forming the yellow filter 2Y by photolithography are performed. Since it is provided, the residue of the colored resin (red resin layer RL) can be removed as compared with the case where the red filter is formed by photolithography. Further, the red filter 2R can be formed without breaking the shape.

  As a result, the image pickup device 11T includes a plurality of photoelectric conversion elements provided on the semiconductor substrate 5 and a plurality of types of color filters individually formed on the photoelectric conversion elements, and has color balance and color reproduction. Therefore, the thin image sensor 11T can be manufactured.

  In addition, according to the present embodiment, since the image sensor 11T in which the correction filter 2Blk is formed by optical superimposition of the two colors of the red filter 2R and the violet filter 2V can be manufactured, the light transmittance of the correction filter 2Blk is half value. Can be adjusted by the ratio of the color material. Thereby, the color adjustment can be performed for the corrected red observation data value HDr.

<Seventh Embodiment>
The imaging device 1U in the present embodiment includes at least two or more filters, has transmission suppression characteristics for light on the shorter wavelength side than the first wavelength, and has transmission characteristics for light on the longer wavelength side than the first wavelength. A second filter having transmission suppression characteristics for light having a wavelength longer than the first wavelength and shorter than the second wavelength, and having transmission characteristics for light having a longer wavelength than the second wavelength; Is provided.

  Note that light incident through the first filter and the second filter is received by the first light receiving element and the second light receiving element, respectively, and converted into an electrical signal.

  Specifically, the imaging device 1U has a first wavelength range that exhibits a transmittance of 10% or less in a wavelength range of 400 nm to 600 nm, and is longer than the first wavelength range and is 450 nm to 1100 nm. The filter F1-the filter F7 which has a wavelength range which is the transmittance | permeability of 90% or more in a wavelength range are provided. Supplementally, the first filter and the second filter are names representing relative relationships, and each of the filters F1 to F7 can be the first filter and the second filter.

  The filters F1 to F7 are for capturing white light (transparent), greenish blue light, yellow-green light, yellow light, orange light, red light, and infrared light (represented as black for convenience), respectively. is there. Specifically, the spectral characteristics of the filters F1 to F7 are shown by L1 to L7 in FIG. 33, respectively.

  In the present embodiment, the filters F1, F4, F6, and F7 correspond to the transparent filter 2W, the yellow filter 2Y, the red filter 2R, and the correction filter 2Blk, respectively.

  Next, a method for obtaining a data value for reproducing the incident light received in each of the filters F1 to F7 will be described.

  First, when light is incident on the image sensor 1U, the incident light is received by the corresponding first light receiving element and second light receiving element via the first filter and the second filter which are any one of the filters F1 to F7. Is done. The received light is converted into an electrical signal.

  Subsequently, as shown in FIG. 34, the first filter and the second filter receive light from the data value D1 of light received by the first filter and the data value D2 of light received by the second filter. A wavelength data value DC corresponding to the difference in the wavelength range of light is obtained.

  In other words, the first filter and the second filter constitute an apparent color filter of a color corresponding to the difference between the respective wavelength ranges.

  For example, a blue data value can be obtained based on the filter F1 (white) and the filter F4 (yellow). A green data value can be obtained based on the filter F4 (yellow) and the filter F6 (red). Red data values that are not affected by infrared rays can be obtained from the filter F6 (red) and the filter F7 (black).

  Thereby, since the data values of the three primary colors of light can be obtained, the received incident light can be reproduced.

  Further, for example, by subtracting the filter F2 (greenish blue) and the filter F3 (yellowish green), a greenish blue (greenish blue) data value can be obtained. By the subtraction process between the filter F3 (yellowish green) and the filter F4 (yellow), a yellowish green data value is obtained. By subtracting the filter F4 (yellow) and the filter F5 (orange), a yellow data value is obtained. By subtracting the filter F5 (orange) and the filter F6 (red), an orange data value is obtained.

  That is, according to the method described above, by using two filters constituting the first filter and the second filter among the filters F1 to F7, not only the received incident light is reproduced, but also finer detail. Color extraction is possible.

  In addition, in this embodiment, although seven types of filters F1-F7 were illustrated, it cannot be overemphasized that it is not restricted to this. That is, it has the 1st wavelength range which shows the transmittance | permeability of 10% or less in the wavelength range of 400 nm-600 nm, and is 90% or more in the wavelength range longer than the said 1st wavelength range and 450 nm-1100 nm. The present embodiment does not exclude the color filter having a wavelength region that is a transmittance.

  Further, the image pickup device 1U according to the present embodiment can be manufactured by the method according to the fifth or sixth embodiment. That is, when manufacturing the image pickup device 1U including a plurality of types of color filters having different color material content ratios, a high ratio color filter having the highest color material content ratio among the color filters is formed by dry etching. It can be manufactured by forming a low ratio color filter other than the above by a photolithography method.

  If the first color filter is formed by dry etching, the shape of the first color filter is improved. Further, no residue is generated in other portions of the first color filter. Therefore, even if the remaining color filters are subsequently formed by photolithography, the shape of the remaining color filters can be formed well. This has the effect of improving the image quality of the image sensor. Therefore, it is desirable to form a high ratio color filter as the first color filter by dry etching. Even if the ratio is not high, it is desirable to form a color filter with high visibility such as Yellow or Green, or a filter with a large number of pixels in a Bayer array by dry etching as the first color filter.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine a component suitably in different embodiment.

FIG. 3 is a front view illustrating an example of an arrangement state of filters in the image sensor according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating an example of an image sensor according to the first embodiment. Sectional drawing which shows the other example of the image pick-up element which concerns on 1st Embodiment. The graph which shows an example of the spectral transmittance about a transparent filter, a yellow filter, a red filter, and a correction filter. The graph which shows an example of the spectral transmittance about the apparent blue filter, green filter, and red filter obtained by the calculation of the image sensor according to the first embodiment. The graph which shows the example of the actual spectral characteristic of the conventional image pick-up element. 3 is a graph illustrating an example of spectral characteristics of a correction filter of the image sensor according to the first embodiment. The front view which shows an example of the arrangement state of the filter in the image pick-up element which concerns on the 2nd Embodiment of this invention. Sectional drawing which shows an example of the image pick-up element which concerns on 2nd Embodiment. Sectional drawing which shows an example of the image pick-up element which concerns on the 3rd Embodiment of this invention. Sectional drawing which shows the example of the 1st process of the manufacturing process of the image pick-up element which concerns on 3rd Embodiment. Sectional drawing which shows the example of the 2nd process of the manufacturing process of the image pick-up element which concerns on 3rd Embodiment. Sectional drawing which shows the example of the 3rd process of the manufacturing process of the image pick-up element which concerns on 3rd Embodiment. Sectional drawing which shows the example of the 4th process of the manufacturing process of the image pick-up element which concerns on 3rd Embodiment. Sectional drawing which shows the example of the 5th process of the manufacturing process of the image pick-up element which concerns on 3rd Embodiment. The front view which shows the 1st example of the arrangement position of the light shielding film of the image pick-up element which concerns on the 4th Embodiment of this invention. Sectional drawing which shows the 2nd example of the installation position of the light shielding film of the image pick-up element which concerns on 4th Embodiment. It is a front view which shows an example of the arrangement state of the filter in the image pick-up element 11S which concerns on the 5th Embodiment of this invention. It is sectional drawing which shows an example of the image pick-up element 11S which concerns on 5th Embodiment. It is a figure for demonstrating the manufacturing method of the image pick-up element 11S which concerns on 5th Embodiment. It is a figure for demonstrating the manufacturing method of the image pick-up element 11S which concerns on 5th Embodiment. It is a figure for demonstrating the manufacturing method of the image pick-up element 11S which concerns on 5th Embodiment. It is a figure for demonstrating the manufacturing method of the image pick-up element 11S which concerns on 5th Embodiment. It is a figure for making the effect of the manufacturing method of the image sensor in a 5th embodiment. It is a figure which prints and shows the image pick-up element manufactured with the manufacturing method in 5th Embodiment. It is a front view which shows an example of the arrangement state of the filter in the image pick-up element 11T which concerns on the 6th Embodiment of this invention. It is sectional drawing which shows an example of the image pick-up element 11T which concerns on 6th Embodiment. It is a figure for demonstrating the manufacturing method of the image pick-up element 11T which concerns on 6th Embodiment. It is a figure for demonstrating the manufacturing method of the image pick-up element 11T which concerns on 6th Embodiment. It is a figure for demonstrating the manufacturing method of the image pick-up element 11T which concerns on 6th Embodiment. It is a figure for demonstrating the manufacturing method of the image pick-up element 11T which concerns on 6th Embodiment. It is a figure for demonstrating the manufacturing method of the image pick-up element 11T which concerns on 6th Embodiment. It is a figure which shows an example of the spectral characteristic of the filter F1-filter F7 which concerns on the 7th Embodiment of this invention. It is a figure for demonstrating the concept of the apparent color filter which concerns on 7th Embodiment. The graph which shows the example of the relationship of the transmittance | permeability of a preferable near-infrared cut filter with respect to human visual sensitivity, the sensitivity of a light receiving element, and the sensitivity of a light receiving element. The graph which shows the example of the relationship between the wavelength of light and the transmittance | permeability in a reflection type infrared cut filter and an infrared absorption type infrared cut filter. The graph which shows an example of the spectral transmittance of the color filter of three primary colors of red, green, and blue.

Explanation of symbols

  1, 1U, 9, 11, 11S, 11T, 14, 17 ... imaging device, 2 ... filter layer, 2W, 10W, 12W ... transparent filter, 2Y ... yellow filter, 2R ... red filter, 2Blk ... correction filter, 2V ... Violet filter, 3W ... incident light receiving element 3W, 3Y ... yellow light receiving element, 3R ... red light receiving element, 3Blk ... corrected light receiving element, 4 ... calculating unit, 4B ... blue calculating unit, 4G ... green calculating unit, 4R ... red Arithmetic unit, 5 ... semiconductor substrate, 6 ... planarization layer, 7 ... resin layer, 8 ... microlens, 12 ... planarization layer, 13 ... photosensitive phenol resin, 13a ... lens matrix, 15, 19 ... light shielding film, DESCRIPTION OF SYMBOLS 16 ... Film | membrane, 18 ... Effective pixel part of an image pick-up element, BL ... Black resin layer, RL ... Red resin layer, VL ... Purple resin layer, PL ... Photoresist layer, M ... Mask, F1-F7 ... Filter.

Claims (8)

A plurality of photoelectric conversion elements provided on a semiconductor substrate;
An image pickup device manufacturing method for manufacturing an image pickup device that is individually formed on the plurality of photoelectric conversion elements and includes a plurality of types of color filters and transparent filters having different color material content ratios,
A step of forming one or more kinds of high ratio color filters having a relatively high colorant content ratio among the color filters by dry etching;
Forming a low ratio color filter other than the high ratio color filter by a photolithography method using a developer; and
Forming a transparent resin layer so as to cover the high ratio color filter and the low ratio color filter, and forming a transparent filter. A plurality of photoelectric conversion elements provided on a semiconductor substrate;
An image pickup device manufacturing method for manufacturing an image pickup device that is individually formed on the plurality of photoelectric conversion elements and includes a plurality of types of color filters and transparent filters having different color material content ratios,
Forming a high ratio color filter having the highest color material content ratio among the color filters by dry etching;
Forming a low ratio color filter other than the high ratio color filter by a photolithography method using a developer; and
Forming a transparent resin layer so as to cover the high ratio color filter and the low ratio color filter, and forming a transparent filter. A plurality of photoelectric conversion elements provided on a semiconductor substrate;
An image pickup device manufacturing method for manufacturing an image pickup device that is individually formed on the plurality of photoelectric conversion elements and includes a plurality of types of color filters and transparent filters having different color material content ratios,
Forming a colored resin layer to be a high ratio color filter having the highest color material content ratio among the color filters;
Forming a photoresist layer on the colored resin layer;
Patterning the photoresist layer to expose a colored resin layer in the pattern of the high-ratio color filter;
Dry etching the colored resin layer exposed from the pattern of the photoresist layer;
Forming the low-ratio color filter other than the high-ratio color filter in a region different from the high-ratio color filter on the semiconductor substrate after forming the high-ratio color filter by a photolithography method using a developer;
Applying a transparent resin layer by spin coating so as to cover the high-ratio color filter and low-ratio color filter on the semiconductor substrate;
Thermosetting the transparent resin layer to form a planarization layer including a transparent filter;
And a step of dry-etching the planarization layer on the photoelectric conversion element to form a microlens. The high ratio color filter has a transmittance of 10% or less in a wavelength region of 400 nm to 600 nm, and a transmittance of 90% or more in a wavelength region of 750 nm to 1100 nm. 4. A method for manufacturing an image pickup device according to any one of items 3 to 4. The high-ratio color filter and the low-ratio color filter have a first wavelength range that exhibits a transmittance of 10% or less in a wavelength range of 400 nm to 600 nm, and are longer than the first wavelength range and have a wavelength range of 450 nm. method for manufacturing an imaging element according to any one of claims 1 to 4, characterized in that it has a wavelength range the transmittance of 90% or more in the wavelength range of ～1100Nm. The high ratio color filter and the low ratio color filter are:
A yellow filter used to extract the yellow component of light;
A red filter used to extract the red component of the light;
Has a transmission suppressing characteristics in the visible light wavelength range, according to any one of claims 1 to 5, characterized in that it comprises a correction filter having the transmission characteristics in the long wavelength side than the visible light wavelength region Manufacturing method of imaging device. The transparent filter, method of manufacturing the image sensor according to any one of claims 1 to 6, characterized in that it has a transmittance of 90% or higher in the wavelength range of 400 nm to 1100 nm. The transparent filter, method of manufacturing the image sensor according to any one of claims 1 to 7, characterized in that absorbs ultraviolet light at shorter wavelengths than 400 nm.

Images