JP5429208B2 - Solid-state image sensor, camera module, and electronic device module - Google Patents

Description

  The present invention relates to a solid-state imaging device in which a plurality of unit pixels that convert and output signal charges photoelectrically converted by a photoelectric conversion device are arranged, a camera module including the solid-state imaging device, and an electronic device module.

  As the solid-state imaging device, a CMOS solid-state imaging device typified by a CMOS image sensor and a CCD solid-state imaging device typified by a CCD image sensor are known. Taking a CMOS solid-state imaging device as an example, an example of the cross-sectional structure is shown in FIG.

  FIG. 9 shows an example of a conventional surface irradiation type CMOS solid-state imaging device. The CMOS solid-state imaging device 1 includes a p-type semiconductor well region 3 of a second conductivity type formed on a first conductivity type, for example, an n-type silicon semiconductor substrate 2, and pixel separation of the p-type semiconductor well region 3. In a unit pixel area partitioned by the area 10, a photodiode 5 serving as a photoelectric conversion unit and a MOS transistor group 6 including a plurality of MOS transistors are formed. The photodiode 5 is formed of an n-type semiconductor region surrounded by the pixel isolation region 3 and the p-type semiconductor well region 3. That is, it is formed by a low impurity concentration n-type semiconductor region (n− semiconductor region) 11 deep from the surface and a high impurity concentration n-type semiconductor region (n + semiconductor region) 12 on the surface side. Further, a p + accumulation layer 13 made of a p-type semiconductor region having a high impurity concentration for suppressing dark current generation is formed at the surface side interface of the n + semiconductor region 12. The photodiode 5 is configured as a so-called HAD (Hole Accumulation Diode) sensor.

  The MOS transistor group 6 includes a read transistor 7 connected to a photodiode and other MOS transistors 8. The read transistor 7 has an n + source / drain region 14 formed in the P-type semiconductor well region 3, an n + semiconductor region 12 of the photodiode 5, and gate insulation on the substrate surface between the n + source / drain region 14 and the photodiode 5. The gate electrode 18 is formed through a film. The other MOS transistor 8 includes n + source / drain regions 15 and 16 formed in the P-type semiconductor well region 3 and a gate formed on the substrate surface between the n + source / drain regions 15 and 16 via a gate insulating film. And the electrode 19. For example, when it is composed of four MOS transistors, it is composed of a read transistor, a reset transistor, an amplifier transistor, and a vertical selection transistor. Furthermore, a multilayer wiring layer 25 is formed on the substrate surface via an interlayer insulating film 23. Although not shown, a color filter, an on-chip lens, and the like are also formed.

  Light incident on the photodiode 5 is irradiated from the surface side of the substrate on which the MOS transistors that perform signal charge accumulation and readout operations are formed. In such a front-illuminated CMOS solid-state imaging device 1, an antireflection film 26 is formed in order to increase the light collection efficiency on the substrate surface side photodiode 5. In the front-illuminated type CMOS solid-state imaging device 1, normally four or more layers of silicon oxide (with a protective film for preventing deterioration over time such as a photodiode, a group of MOS transistors, and a wiring layer, and an interlayer insulating film under the protective film) An SiO) film and a silicon nitride (SiN) film are present on the photodiode 5.

  The reason why four or more insulating films are formed on the light irradiation surface side is that a thick interlayer insulating film (silicon oxide film 23) is required in the middle because the multilayer wiring layer 25 is provided. In the illustrated example, a four-layer film of a silicon oxide (SiO) film 21, a silicon nitride (SiN) film 22, a silicon oxide (SiO) film 23, and a silicon nitride (SiN) film 24 is formed on the light irradiation surface side. .

  On the other hand, in a front-illuminated CMOS solid-state imaging device, there is a wiring layer formed of a light-shielding material. Therefore, in order to optimize light collection within the pixel and improve sensitivity, a layer separate from the on-chip lens is used. An inner lens may be formed. In the case of having an in-layer lens, five or six layers of insulating films having different refractive indexes are present on the silicon substrate.

  The CCD solid-state imaging device may also have an in-layer lens, and the same four or more layers of silicon oxide (SiO) film and silicon nitride (SiN) film are formed on the light irradiation surface side.

  Patent Document 1 proposes an example of a surface irradiation type CMOS solid-state imaging device in which four or more insulating films are formed on a light irradiation surface on the surface side.

JP 2003-224249 A

  By the way, when an anti-reflection film is composed of four or more layers of silicon oxide film and silicon nitride film, it has spectral characteristics with so-called ripples that rise and fall in a short period due to interference with the film of refractive index, and the sensitivity of the image sensor is lost. doing. FIG. 5 is a graph showing the wavelength dependence of the photoelectric conversion rate due to the difference in the film configuration of the antireflection film on the light irradiation surface. The horizontal axis in FIG. 5 represents the wavelength of the irradiation light. The vertical axis is proportional to the product of the light transmittance and the light absorptance in silicon (transmittance × Si absorptance), that is, the photoelectric conversion efficiency, and corresponds to the sensitivity.

  Curve C in FIG. 5 shows a plasma silicon nitride (PSiN) film having a thickness of 500 nm, a silicon oxide (SiO) film having a thickness of 5000 nm, a silicon nitride (SiN) film having a thickness of 50 nm, and a silicon oxide having a thickness of 15 nm. The spectral characteristics of an antireflection film having a four-layer film structure in which (SiO) films are sequentially deposited from below are shown. As can be seen from the curve C, the spectral characteristic of the antireflection film by the four-layer film is a spectral characteristic with a ripple that rises and falls in a short cycle, and its integrated value (integrated value of photoelectric conversion efficiency) becomes sensitivity. If you look at it, it will shift downward.

  Curve B in FIG. 5 shows three layers in which a plasma silicon nitride (PSiN) film having a thickness of 500 nm, a silicon nitride (SiN) film having a thickness of 50 nm, and a silicon oxide (SiO) film having a thickness of 15 nm are sequentially deposited from below. It is a spectral characteristic of the antireflection film of a film structure. This is a spectral characteristic that rises and falls with a coarser period than the antireflection film of the four-layer film.

  Further, in the case of a surface irradiation type solid-state imaging device, in the case of a solid-state imaging device in which an in-layer lens is formed in order to improve sensitivity, five or six layers of films having different refractive indexes exist on the silicon substrate. The sensitivity loss becomes more prominent. However, when an intralayer lens is formed, the condensing efficiency by the intralayer lens is more effective than the effect of the antireflection film by the multilayer film. As the structure of the antireflection film, the sensitivity of the image sensor is lowered as the number of layers of the film increases.

In view of the above, the present invention provides a solid-state imaging device that improves the antireflection efficiency and enables higher sensitivity, and a camera module and an electronic device module including the solid-state imaging device.
The present invention also provides a solid-state image pickup device that reduces shading and optical color mixing to adjacent pixels, a solid-state image pickup device that can realize a small sensor and a lens module, a camera module, and an electronic device module. It is.

A solid-state imaging device according to the present invention is formed in a semiconductor substrate, a pixel separation region by a semiconductor region from the front surface to the back surface of the semiconductor substrate, and each pixel region separated by the pixel separation region. A photoelectric conversion portion extending from the front surface side to the back surface side and having a width in the surface direction of the semiconductor substrate extended on the back surface side with respect to the front surface side, and an interlayer insulating film on the surface of the semiconductor substrate A plurality of layers of wiring formed, an antireflection film formed on the back surface serving as a light irradiation surface of the semiconductor substrate, and a color filter or on-chip provided on the antireflection film in contact with the antireflection film have a lens, the antireflection film is a single layer film composed so that the refractive index increases toward the color filter or the on-chip lens side from the light irradiation surface.

  A solid-state imaging device according to the present invention is formed in a semiconductor substrate, a pixel separation region by a semiconductor region from the front surface to the back surface of the semiconductor substrate, and each pixel region separated by the pixel separation region. A pixel comprising a photoelectric conversion portion extending from the front surface side to the back surface side and a plurality of transistors existing on the front surface side of the semiconductor substrate, and a plurality of layers of wiring formed on the surface of the semiconductor substrate via an interlayer insulating film And an antireflection film formed on the back surface serving as a light irradiation surface of the semiconductor substrate, and an on-chip lens formed on the antireflection film.

The camera module according to the present invention includes a solid-state imaging device, an optical lens system, and a signal processing device. The solid-state imaging device is formed in a semiconductor substrate, a pixel separation region by a semiconductor region from the front surface to the back surface of the semiconductor substrate, and each pixel region separated by the pixel separation region, and from the front surface side of the semiconductor substrate A photoelectric conversion portion extending on the back surface side and having a width in the surface direction of the semiconductor substrate extended on the back surface side with respect to the front surface side, and formed on the surface of the semiconductor substrate via an interlayer insulating film A multilayer wiring, an antireflection film formed on the back surface as the light irradiation surface of the semiconductor substrate, and a color filter or an on-chip lens provided on the antireflection film and in contact with the antireflection film. The antireflection film is a single-layer film configured such that the refractive index increases from the light irradiation surface side toward the color filter or on-chip lens side .

  The camera module according to the present invention includes a solid-state imaging device, an optical lens system, and a signal processing device. The solid-state imaging device is formed in a semiconductor substrate, a pixel separation region by a semiconductor region from the front surface to the back surface of the semiconductor substrate, and each pixel region separated by the pixel separation region, and from the front surface side of the semiconductor substrate A pixel composed of a photoelectric conversion portion extending on the back surface side and a plurality of transistors existing on the surface side of the semiconductor substrate, a plurality of layers of wiring formed on the surface of the semiconductor substrate via an interlayer insulating film, and An antireflection film formed on the back surface serving as a light irradiation surface of the semiconductor substrate, and an on-chip lens formed on the antireflection film. A color filter is provided on the optical lens system side.

An electronic device module according to the present invention includes a solid-state imaging device, an optical lens system, and a signal processing device. The solid-state imaging device is formed in a semiconductor substrate, a pixel separation region by a semiconductor region from the front surface to the back surface of the semiconductor substrate, and each pixel region separated by the pixel separation region, and from the front surface side of the semiconductor substrate A photoelectric conversion portion extending on the back surface side and having a width in the surface direction of the semiconductor substrate extended on the back surface side with respect to the front surface side, and formed on the surface of the semiconductor substrate via an interlayer insulating film A multilayer wiring, an antireflection film formed on the back surface serving as a light irradiation surface of the semiconductor substrate, and a color filter or an on-chip lens provided on the antireflection film in contact with the antireflection film. Yes, and the antireflection film is a single layer film composed so that the refractive index increases toward the color filter or the on-chip lens side from the light irradiation surface.

  An electronic device module according to the present invention includes a solid-state imaging device, an optical lens system, and a signal processing device. The solid-state imaging device is formed in a semiconductor substrate, a pixel separation region by a semiconductor region from the front surface to the back surface of the semiconductor substrate, and each pixel region separated by the pixel separation region, and from the front surface side of the semiconductor substrate A pixel composed of a photoelectric conversion portion extending on the back surface side and a plurality of transistors existing on the surface side of the semiconductor substrate, a plurality of layers of wiring formed on the surface of the semiconductor substrate via an interlayer insulating film, and An antireflection film formed on the back surface serving as a light irradiation surface of the semiconductor substrate, and an on-chip lens formed on the antireflection film. A color filter is provided on the optical lens system side.

  The solid-state imaging device according to the present invention is configured as a back-illuminated type CMOS solid-state imaging device, and an antireflection film is formed on the back surface that is a light irradiation surface of the semiconductor substrate, so that the antireflection efficiency is improved and the photoelectric conversion efficiency is improved. To do. In addition, since color filters and on-chip lenses are stacked on the antireflection film, the uppermost on-chip lens approaches the back surface, which is the light irradiation surface of the semiconductor substrate, and shading is caused by the difference in the incident angle within the imaging surface. And optical color mixing to adjacent pixels is reduced.

  The solid-state imaging device according to the present invention is configured as a back-illuminated type CMOS solid-state imaging device, and an antireflection film is formed on the back surface that is a light irradiation surface of the semiconductor substrate, so that the antireflection efficiency is improved and the photoelectric conversion efficiency is improved. To do. Furthermore, since the on-chip lens is formed on the antireflection film, the uppermost on-chip lens approaches the back surface, which is the light irradiation surface of the semiconductor substrate, and is adjacent to the shading caused by the difference in the incident angle in the imaging surface. Optical color mixing to the pixel is reduced.

  According to the solid-state imaging device according to the present invention, the photoelectric conversion efficiency is improved by forming the antireflection film on the light irradiation surface on the back surface of the back-illuminated CMOS solid-state imaging device, and the sensitivity of the back-illuminated solid-state imaging device is improved. Can be further improved. In addition, since the color filter and on-chip lens are stacked on the antireflection film, the top-layer on-chip lens and the semiconductor substrate surface that performs photoelectric conversion approach each other, and the shading caused by the difference in the incident angle in the screen and the adjacent pixels Can be reduced. In addition, if the shading and optical color mixing are allowed to the same extent as the conventional surface irradiation type solid-state imaging device, the incident angle around the imaging region can be increased, that is, the exit pupil distance can be shortened, It is possible to realize a small module (for example, a camera module, an electronic module, etc.) configured as a single device by integrating a solid-state imaging device and a lens. Furthermore, when the antireflection film is a two-layer film, the number of steps can be reduced, and the cost can be reduced.

  According to the solid-state imaging device according to the present invention, the backside illumination is performed by forming the antireflection film on the light irradiation surface on the backside of the backside illumination type CMOS solid-state imaging device and forming the on-chip lens on the antireflection film. In addition to further improving the sensitivity of the solid-state image sensor, the top-layer on-chip lens and the semiconductor substrate surface that performs photoelectric conversion approach each other, and shading due to the difference in the incident angle in the screen and the optical to the adjacent pixels Color mixing can be further reduced.

According to the camera module of the present invention, by providing the solid-state imaging device, it is possible to improve sensitivity, reduce shading and optical color mixing to adjacent pixels, and realize a more compact camera module.
When an on-chip lens is formed on the antireflection film of the solid-state imaging device and a color filter is disposed on the optical lens side, the on-chip lens and the back surface of the semiconductor substrate can be brought closer to each other, and shading and color mixing are further reduced.

According to the electronic device module of the present invention, by providing the solid-state imaging device, sensitivity can be improved, shading and optical color mixing to adjacent pixels can be reduced, and a more compact electronic device module can be realized. .
When an on-chip lens is formed on the antireflection film of the solid-state imaging device and a color filter is disposed on the optical lens side, the on-chip lens and the back surface of the semiconductor substrate can be brought closer to each other, and shading and color mixing are further reduced.

It is a schematic block diagram which shows embodiment of the backside illumination type CMOS solid-state image sensor concerning this invention. It is sectional drawing which shows an example of the cross-sectional structure of 1 pixel in the CMOS solid-state image sensor of embodiment shown in FIG. It is a schematic diagram which shows embodiment of the anti-reflective film in the CMOS solid-state image sensor of embodiment shown in FIG. AC is a cross-sectional view showing an example of a two-layer antireflection film according to the present invention. It is a graph which shows the wavelength dependence of the photoelectric conversion rate by the difference in the film | membrane structure on a light irradiation surface. It is a block diagram which shows other embodiment of the antireflection film concerning this invention. It is a schematic block diagram which shows the other example of arrangement | positioning of a color filter at the time of applying this invention to the module provided with the solid-state image sensor and the optical lens system, or an imaging camera. It is a schematic block diagram which shows embodiment of the module which concerns on this invention. It is a block diagram of the conventional surface irradiation type CMOS solid-state image sensor.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a pixel portion showing an embodiment in which a solid-state imaging device according to the present invention is applied to a back-illuminated CMOS solid-state imaging device. FIG. 2 is a detailed sectional view of the one pixel.

  As shown in FIG. 1, the backside illumination type CMOS solid-state imaging device 31 according to the present embodiment forms a pixel isolation region 33 including a second conductivity type semiconductor region on a first conductivity type silicon semiconductor substrate 32. In order to read out the photodiode 34 serving as a photoelectric conversion unit and the signal charge accumulated in the photodiode 34 so that each pixel region partitioned by the pixel isolation region 33 is surrounded by the second conductivity type semiconductor region. The required number of MOS transistors 35 are formed. The pixel isolation region 33 is formed in the depth direction so as to reach the back surface from the front surface of the substrate 32. The MOS transistor 35 is formed on the front surface side of the substrate 32, and the photodiode 34 is formed so as to extend partially on the back surface side of the substrate 32 so as to extend below the MOS transistor 35.

  A gate electrode 37 of the MOS transistor 35 is formed on the surface of the substrate 32, a multilayer wiring layer 39 is formed thereon via an interlayer insulating film 38, and a support substrate 40 is further formed on the interlayer insulating film 38. Is formed. As the support substrate 40, for example, a silicon substrate can be used. On the other hand, an on-chip color filter 42 is formed on the back surface of the semiconductor substrate 32 via an antireflection film 41 according to the present invention described later, and an on-chip lens 43 is formed on the color filter 42 so as to correspond to each pixel. Is done. In the CMOS solid-state imaging device 31, light L is irradiated to the photodiode 34 from the back surface of the substrate through the on-chip lens 43.

  An example of a specific configuration of the unit pixel of the solid-state image sensor 31 is shown in FIG. In this example, a pixel isolation region 33 made of a p-type semiconductor region of the second conductivity type is formed so as to partition each pixel region 101 on an n-type silicon semiconductor substrate 32 of the first conductivity type. The pixel isolation region 33 is formed of a relatively low concentration p-type semiconductor region. A p-type semiconductor well region 51 is formed on the surface of the n-type semiconductor substrate 32 in the pixel region 101 so as to connect to the p-type pixel isolation region 33 and partially extend into the pixel region 101. The photodiode 34 serving as a photoelectric conversion unit is formed of an n-type semiconductor substrate 32 surrounded by a p-type pixel isolation region 33 and a p-type semiconductor well region 51. That is, the photodiode 34 is formed by the n semiconductor region 32A and the high impurity concentration n + semiconductor region 32B on the surface side thereof. A p + accumulation layer 53 made of a high impurity concentration p-type semiconductor region for suppressing dark current generation is formed at the interface on the surface side of the n + semiconductor region 32B. Further, in common to each pixel region, p + accumulation comprising a high impurity concentration p-type semiconductor region for suppressing dark current generation on the back surface of the n-type semiconductor substrate 32, that is, the interface on the back surface side of the n semiconductor region 32A. Layer 54 is formed.

  The photodiode 34 is configured as a so-called HAD sensor because it has p + accumulation layers 53 and 54 on the front surface of the n + semiconductor region 32B and the back surface of the n semiconductor region 32A. Further, since the n semiconductor region 32A extends below the p-type semiconductor well region 51, the photodiode 34 is formed in a large area so as to cover the entire pixel region.

  On the other hand, the MOS transistor 35 is formed in the p-type semiconductor well region 51. That is, for example, when one pixel is composed of one photodiode and four MOS transistors, the MOS transistor 35 includes a read transistor, a reset transistor, an amplifier transistor, and a vertical selection transistor. In FIG. 2, one n + source / drain region 61 is formed in the p-type semiconductor well region 51 in the vicinity of the photodiode 34, and the one n + source / drain region 61 and the other source / drain region serve as the photodiode. A gate electrode 37 is formed on the p-type semiconductor well region 51 between the n + semiconductor regions 52 of 34 via a gate insulating film to form the read transistor Tr1.

  Further, corresponding n + source / drain regions 62 and 63 are formed in the other part of the p-type semiconductor well region 51, and a gate insulating film is formed on the p-type semiconductor well region 51 between the n + source / drain regions 62 and 63. The gate electrode 37 is formed through the other transistors, and other MOS transistors, that is, the reset transistor Tr2, the amplifier transistor Tr3, and the vertical selection transistor Tr4 are formed.

  A multilayer wiring layer 39 is formed on the surface of the semiconductor substrate via an interlayer insulating film 38 made of, for example, a silicon oxide film, and a support substrate 40 made of, for example, a silicon substrate is bonded onto the interlayer insulating film 38. An antireflection film 41 of the present invention is formed on the light irradiation surface 56 on the back surface of the semiconductor substrate, and an on-chip lens 43 is formed on the antireflection film 41 via an on-chip color filter 42.

  In the present embodiment, as particularly shown in FIG. 3, the antireflection film 41 on the light irradiation surface 56 on the back surface side of the substrate is reflected by two layers of films 66 and 67 having a refractive index different from that of the silicon substrate 32. It is formed by the prevention film 411. In FIG. 3, in order to clarify the configuration of the antireflection film 411, the portions other than the antireflection film 411 are the same as those in FIGS. 1 and 2, so that the photodiode, the MOS transistor, the wiring layer, and the like are omitted. The two-layer antireflection film 411 is formed of a two-layer film 66 or 67 selected from a silicon oxide (SiO) film, a silicon nitride (SiN) film, a silicon oxynitride (SiON) film, and polycrystalline silicon. be able to. FIG. 4 shows a configuration example of the antireflection film 411.

In FIG. 4A, a silicon oxide (SiO) film 66 and a silicon nitride (SiN) film 67 are sequentially deposited on the light irradiation surface 56 on the back surface of the silicon substrate to form a two-layer antireflection film 411.
In FIG. 4B, a silicon oxide (SiO) film 66 and a silicon oxynitride (SiON) film 67 are sequentially deposited on the light irradiation surface 56 on the back surface of the silicon substrate to form a two-layer antireflection film 411.
In FIG. 4C, a silicon oxynitride (SiON) film 66 and a silicon nitride (SiN) film 67 are sequentially deposited on the light irradiation surface 56 on the back surface of the silicon substrate to form a two-layer antireflection film 411.
The refractive index of the silicon oxynitride film varies with the composition ratio of nitrogen N, and the refractive index increases as the composition ratio of nitrogen N increases. The films 66 and 67 are deposited in order from the light irradiation surface 56 to a film having a small refractive index.

  As the antireflection film 411, a combination of a silicon oxide (SiO) film 66 and a silicon nitride (SiN) film 67 is preferable. At this time, the film thickness of the silicon oxide (SiO) film 66 is preferably 25 nm or less (not including 0). The thickness of the silicon oxide film can be about 1 nm, and can be as thin as possible. The thickness of the silicon nitride film 67 is preferably in the range of 40 nm to 60 nm. If the thickness of the silicon oxide film 66 is 25 nm or less, the spectral characteristics according to the present invention indicated by the curve A in FIG. 5 described later are higher than the average spectral characteristics of the four-layer film (see the curve C). The photoelectric conversion efficiency can be improved. When the thickness of the silicon nitride film 67 is in the range of 40 nm to 60 nm, the photoelectric conversion efficiency can be improved for the same reason as described above.

  In FIG. 5, a curve A is a spectral characteristic showing the wavelength dependence of the photoelectric conversion efficiency of the antireflection film 411 by the two-layer film of the silicon oxide film 66 and the silicon nitride film 67 according to the present embodiment. This curve A is a characteristic when the thickness of the silicon oxide film 66 is about 15 nm and the thickness of the silicon nitride film 67 is about 50 nm. The photoelectric conversion efficiency is improved and the sensitivity of the imaging device is improved as compared with the four-layer film (see curve C) and the three-layer film (curve B).

According to the backside illuminating type CMOS solid-state imaging device 31 according to the present embodiment, the reflection of the antireflection film 411 by the two-layer film on the light irradiation surface on the backside of the substrate, preferably the reflection of the two-layer film of silicon oxide film and silicon nitride film By forming the prevention film, the antireflection efficiency of incident light can be improved and the sensitivity of the image sensor can be improved.
The antireflection film 411 formed of the two-layer film is a back-illuminated CMOS solid-state imaging device, and thus can be formed without being restricted by a multilayer wiring layer.
In the solid-state imaging device 31 of the present embodiment, since the photodiode 34 facing the back surface of the substrate is formed in the entire pixel region, the opening of the photodiode 34 becomes 100%, and further improvement in photoelectric conversion efficiency is obtained. A highly sensitive solid-state imaging device can be obtained.

In addition, since the antireflection film 411 of the two-layer film is provided, the on-chip lens 43 that is the uppermost layer of the light irradiation surface and the silicon surface that performs photoelectric conversion approach each other, thereby causing shading caused by a difference in incident angle in the imaging surface. , Optical color mixing to adjacent pixels can be reduced.
In addition, if the shading and optical color mixing are allowed to the same extent as the conventional surface irradiation type CMOS solid-state imaging device, the incident angle around the imaging region can be increased, and the so-called exit pupil distance can be shortened, It is possible to realize a small module (for example, a camera module, an electronic module, etc.) configured as a single device by integrating a solid-state imaging device and a lens. Furthermore, by providing the antireflection film 411 with a two-layer film, it is possible to reduce the manufacturing process and the cost by reducing the process.

  As the antireflection film 41 according to the present invention shown in FIG. 1, a two-layer antireflection film 411 is configured in FIG. 4. In addition, as shown in FIG. 6, an antireflection film 422 using a single layer film is configured. can do. In this case, the single-layer antireflection film 412 is formed so that the refractive index varies stepwise in the film thickness direction. For example, a silicon oxynitride (SiON) film can be used, and the nitrogen composition ratio can be changed in the film thickness direction to form a single-layer antireflection film.

  The present invention can constitute an imaging camera and various modules by incorporating the above-described solid-state imaging device. FIG. 7 shows an embodiment of the back-illuminated CMOS solid-state imaging device 31 and the optical lens system 85 described above, in which a two-layer film or a single-layer antireflection film 41 is formed on the light irradiation surface on the back surface. . The color filter can be arranged between the antireflection film 41 and the on-chip lens 43 (or 89), or on the optical lens system 85 side as shown in FIG. It can also be arranged on the side opposite to the solid-state imaging device or on the opposite side.

  FIG. 8 shows a schematic configuration showing an embodiment of an electronic device module and a camera module according to the present invention. The module configuration of FIG. 8 can be applied to both an electronic device module and a camera module. The module 110 according to the present embodiment includes a solid-state imaging device according to any of the above-described embodiments, for example, a back-illuminated solid-state imaging device 31, an optical lens system 111, an input / output unit 112 signal processing device (Digital Signal Processors) 113, A central processing unit (CPU) 114 for controlling the optical lens system is incorporated into one to form a module. In addition, as the electronic device module or the camera module 115, for example, a module can be formed by only the back-illuminated solid-state imaging device 31 or 71, the optical lens system 111, and the input / output unit 112. Further, for example, a module 116 including a back-illuminated solid-state imaging device 31 or 71, an optical lens system 111, an input / output unit 112, and a signal processing device (Digital Signal Processors) 113 can be configured.

  According to the camera module and the electronic device module according to the present embodiment, the antireflection efficiency of incident light on the solid-state image sensor can be improved, and the sensitivity of the solid-state image sensor in the module can be improved. In addition, shading caused by the difference in incident angle in the imaging surface and optical color mixing to adjacent pixels are reduced. If shading and optical color mixing are allowed to the same extent as a conventional surface irradiation type solid-state imaging device, the exit pupil distance can be shortened, and a smaller module can be realized.

  In addition, even when the solid-state imaging device of the present invention, particularly the back-illuminated solid-state imaging device, is applied to an imaging camera, the antireflection efficiency of incident light to the solid-state imaging device is improved and the sensitivity of the imaging camera is improved. Can do. In addition, shading caused by the difference in incident angle in the imaging surface and optical color mixing to adjacent pixels are reduced. If shading and optical color mixing are allowed to the same extent as those of a conventional surface irradiation type solid-state imaging device, the exit pupil distance can be shortened, and a more compact imaging camera can be realized.

  31..Back-illuminated CMOS solid-state imaging device, 32..Semiconductor substrate, 32A..n semiconductor region, 33..Pixel isolation region, 34..Photodiode, 35..MOS transistor, Tr1..readout transistor, 37 .... Gate electrode, 38 ... Interlayer insulation film, 39 ... Multi-layer wiring layer, 40 ... Support substrate, 41 [411 to 413], 422 ... Antireflection film, 42 ... Color filter, 43 ... On-chip lens, 51 ·· p-type semiconductor well region, 52 ·· n + semiconductor region, 53, 54 ·· p + accumulation layer, 56 ·· Light irradiation surface, 66, 67 ·· Insulating film

Claims (14)

A semiconductor substrate;
A pixel isolation region by a semiconductor region from the front surface to the back surface of the semiconductor substrate;
Formed in each pixel region separated by the pixel separation region, extends from the front surface side to the back surface side of the semiconductor substrate, and the width in the surface direction of the semiconductor substrate extends on the back surface side relative to the front surface side A photoelectric conversion unit,
A plurality of layers of wiring formed on the surface of the semiconductor substrate via an interlayer insulating film;
An antireflection film formed on the back surface to be the light irradiation surface of the semiconductor substrate;
Wherein the anti-reflective coating, have a color filter or the on-chip lens provided in contact with the antireflection film,
The antireflection film is a solid-state imaging device that is a single-layer film configured such that a refractive index increases from the light irradiation surface side toward the color filter or the on-chip lens side . The solid-state imaging device according to claim 1, wherein a color filter is provided on the antireflection film in contact with the antireflection film, and the on-chip lens is provided in contact with the color filter. The solid-state imaging device according to claim 1, wherein an on-chip lens is provided on the antireflection film in contact with the antireflection film. An accumulation layer having a conductivity type opposite to that of the photoelectric conversion unit is provided on the light irradiation surface side of the semiconductor substrate in contact with the photoelectric conversion unit.
The solid-state imaging device according to claim 1, wherein the antireflection film is provided in contact with the accumulation layer. The solid according to claim 1, wherein the antireflection film is formed so that a nitrogen composition ratio increases in a film thickness direction from the light irradiation surface toward the color filter or the on-chip lens. Image sensor. Wherein the pixel surface of the separated semiconductor substrate by isolation regions, the solid-state imaging device according to any one of claims 1 to 5, a plurality of transistors provided in the pixel with the photoelectric conversion unit. A solid-state imaging device, an optical lens system, and a signal processing device;
The solid-state imaging device is
A semiconductor substrate;
A pixel isolation region by a semiconductor region from the front surface to the back surface of the semiconductor substrate;
Formed in each pixel region separated by the pixel separation region, extends from the front surface side to the back surface side of the semiconductor substrate, and the width in the surface direction of the semiconductor substrate extends on the back surface side relative to the front surface side A photoelectric conversion unit,
A plurality of layers of wiring formed on the surface of the semiconductor substrate via an interlayer insulating film;
An antireflection film formed on the back surface to be the light irradiation surface of the semiconductor substrate;
Wherein the anti-reflective coating, have a color filter or the on-chip lens provided in contact with the antireflection film,
The antireflection film is a camera module that is a single-layer film configured such that a refractive index increases from the light irradiation surface side toward the color filter or the on-chip lens side . On the antireflection film, a color filter is provided in contact with the antireflection film, and the on-chip lens is provided in contact with the color filter.
The camera module according to claim 7 . On the antireflection film, an on-chip lens was provided in contact with the antireflection film.
The camera module according to claim 7 . A color filter is provided on the optical lens system side;
The camera module according to claim 9 . A solid-state imaging device, an optical lens system, and a signal processing device;
The solid-state imaging device is
A semiconductor substrate;
A pixel isolation region by a semiconductor region from the front surface to the back surface of the semiconductor substrate;
Formed in each pixel region separated by the pixel separation region, extends from the front surface side to the back surface side of the semiconductor substrate, and the width in the surface direction of the semiconductor substrate extends on the back surface side relative to the front surface side A photoelectric conversion unit,
A plurality of layers of wiring formed on the surface of the semiconductor substrate via an interlayer insulating film;
An antireflection film formed on the back surface to be the light irradiation surface of the semiconductor substrate;
Wherein the anti-reflective coating, have a color filter or the on-chip lens provided in contact with the antireflection film,
The electronic device module is a single-layer film in which the antireflection film is configured to have a refractive index that increases from the light irradiation surface side toward the color filter or the on-chip lens side . On the antireflection film, a color filter is provided in contact with the antireflection film, and the on-chip lens is provided in contact with the color filter.
The electronic device module according to claim 11 . On the antireflection film, an on-chip lens was provided in contact with the antireflection film.
The electronic device module according to claim 11 . A color filter is provided on the optical lens system side;
The electronic device module according to claim 13 .

Images