JP4824096B2 - Reflective liquid crystal display device and manufacturing method thereof - Google Patents

Description

The present invention relates to a method for manufacturing a reflective liquid crystal display device that displays an image by reflecting light incident from the outside, and more particularly to a reflective liquid crystal display device having excellent contrast characteristics and paper whiteness and a method for manufacturing the same.

  Liquid crystal display (LCD) has been actively developed as one of the flat panel displays to replace CRTs, especially notebooks taking advantage of their low power consumption and thinness. It has been put to practical use as a TV, in addition to type computers, car navigation systems, portable terminals, and the like. In general, an electro-optical element using liquid crystal has a liquid crystal layer sandwiched between substrates each having electrodes facing each other, and a polarizing plate is installed on the outside of both substrates. It is structured to install a backlight. The surfaces of the electrodes facing each other are subjected to an alignment process, and a director that averages the direction of liquid crystal molecules is controlled to an initial state of a desired direction.

  The liquid crystal has birefringence, and light incident through the polarizing plate using the backlight as a light source becomes elliptically polarized light and enters the polarizing plate on the opposite side. When a voltage is applied between the opposing electrodes in this state, the alignment state of the directors changes, the birefringence of the liquid crystal layer changes, and the elliptical polarization state incident on the opposite polarizing plate changes. Therefore, an electro-optic effect that the intensity and spectrum of light passing through the electro-optic element changes can be obtained. This electro-optic effect is placed on the type of liquid crystal phase to be used (nematic phase, smectic phase, cholesteric phase, etc.), the initial alignment state, the polarization axis direction of the polarizing plate, the thickness of the liquid crystal layer or the path through which light passes. Depending on the color filter and various optical films. Generally, a structure called TN (Twisted Nematic) or STN (Super Twisted Nematic) using a nematic liquid crystal phase is used.

  There are two types of driving methods for electro-optic elements for display using these liquid crystals: a simple matrix type and an active matrix type using thin film transistors (hereinafter referred to as TFTs) as switching elements. Among these, an active matrix type liquid crystal display device (hereinafter referred to as TFT-LCD) having excellent display quality is widely used in notebook personal computers and the like.

  In addition to the transmissive type in which the light of the backlight built in as the light source is transmitted as described above, the TFT-LCD displays by reflecting the light incident from the outside without using the backlight. There are a reflection type and a semi-transmission type or a partial reflection type having both functions. Since the reflective type does not require a backlight light source like the transmissive type, it consumes less power, is thin, and can be reduced in weight. Therefore, it is attracting attention as a portable terminal LCD.

  Conventionally, reflective TFT-LCDs are also used in the TN or STN system in which polarizing plates are installed on both sides of the opposing substrate. In these systems, the display efficiency is reduced due to the decrease in light use efficiency. There is a problem that the image becomes dark or high-quality color display becomes difficult.

  In order to solve such a problem, for example, a polarizing plate-less mode type that does not use a polarizing plate as described in Non-Patent Documents 1 and 2 has been proposed. In these methods, in order to obtain a bright and clear display, as shown in FIG. 29, indirect incidence not only from the direct incident light 26 from the light source 25 such as a fluorescent lamp or the sun but also from the surrounding wall or the like. It is a very important point to effectively use all the rays of natural light including the light 27 and form the reflecting plate 21 that generates the reflected light 29 that is reflected by the eyes of the observer 28. At the same time, it is important to achieve a high display quality by creating a reflector that exhibits “white close to paper” (hereinafter referred to as “paper white”), which is an indicator of good scattering reflection characteristics, and a high contrast ratio. Become.

  Conventionally, such a reflector is manufactured by forming a concavo-convex shape on an organic resin film, and forming a metal with high reflectivity such as Al or Ag on the organic resin film. A method of controlling reflection characteristics by devising a planar layout is mainly used. For example, in Patent Document 1, after forming a resist pattern on an organic insulating film, by using an etching method, circular convex portions having a diameter of 5 to 30 μm are formed at an interval of 1 μm or more, thereby forming an uneven shape. The method of forming is shown.

  In Patent Document 2, two types of large and small circular pattern protrusions are produced by photolithography using a photosensitive resin film, and the height of the protrusions is changed by controlling the exposure time and the development time. After that, a method of manufacturing a reflector in which a photosensitive resin film is applied to the entire surface to form an uneven shape is disclosed. Patent Document 2 shows that the paper whiteness is improved by reducing the flat portion of the reflector with respect to the relationship between the uneven shape and the paper white characteristic of the display.

  Patent Document 3 discloses a method in which a convex pattern is first formed on a photosensitive resin film by photolithography, and then an organic resin film is applied over the entire surface to form a concavo-convex shape. Further, according to Patent Document 3, according to this method, the shape of the uneven portion formed by the first photolithography can be made smooth (the flat portion can be rounded), so that the specular reflection component on the mirror surface is reduced. It has been shown that good reflection characteristics can be obtained.

  Further, Patent Document 4 discloses a method in which a convex pattern is similarly formed on a photosensitive organic resin film by a photolithography method, and then an interlayer film made of an organic resin is formed thereon. Further, Patent Document 4 discloses a method for realizing a brighter display by optimizing the shape of the first convex pattern so that more light is collected by an observer viewing the display surface.

  As described above, according to the photolithography method using the photosensitive resin film and the etching method using the organic insulating film + photosensitive resin film pattern, a smooth uneven shape can be formed. In addition, it is possible to produce a reflector having excellent scattering and reflection characteristics by a relatively simple process.

JP-A-5-323371 (FIGS. 3 and 4) JP-A-9-258219 (FIGS. 4, 5 and Table 1) JP-A-6-75238 (FIGS. 15 and 16) JP 2002-207214 A (FIGS. 1 to 13)

D.L.White and G.N.Taylor; Appl. Phys., Vol. 45, no. 11, November 1974 p. 4718 T. Sonehara et al .; SID 97 DIGEST 1997 p. 1023

  However, in the conventional reflector forming process described in the above-mentioned document, the unevenness of the finished product varies due to variations in the exposure of the photosensitive resin film, variations in development, or variations in etching. There is a problem that it is difficult to realize the characteristics and causes defects such as display unevenness.

  In addition, according to the process in which a convex pattern is first formed on the photosensitive resin film by photolithography, and then an organic resin film is further applied over the entire surface to form an uneven shape, the photosensitive resin film is completely developed. Since the convex pattern is formed, variations in the convex shape due to development variations can be suppressed, but an organic resin film is further applied thereon, which complicates the process and increases the height of the irregularities. This makes it difficult to achieve excellent scattering and reflection characteristics. Therefore, when trying to reduce the viscosity of the organic resin film in order to increase the height of the unevenness, the area of the flat part will increase and the specular reflection component (specular reflection) will increase. There is a problem that will deteriorate.

The present invention has been made to solve such a problem, and is a reflective TFT-LCD or a part having excellent paper whiteness and a high-quality display characteristic with a bright display panel and a high contrast ratio for an observer. It is an object of the present invention to provide a reflective liquid crystal display device capable of producing a reflective plate of a reflective TFT-LCD by a simple process and a method for manufacturing the same.

The manufacturing method of the reflective liquid crystal display device of the present invention includes a pair of substrates and a liquid crystal layer interposed between the pair of substrates, and the surface of the pair of substrates is uneven on one substrate. And a pixel electrode for reflecting light with irregularities on the surface and covering a part of the insulating layer, wherein a conductive film is formed on the substrate. a first step of forming a gate electrode and a gate wiring made, an insulating film made of SiN or SiO _2, a second step of forming a plurality of convex patterns in the pixel area, made of SiN or SiO ₂ A third step of sequentially forming a gate insulating film, a semiconductor active film made of Si or the like, and an ohmic film; a fourth step of forming a source electrode made of a conductive film, a source wiring, and a drain electrode; and a first step made of an organic resin. Interlayer A fifth step of forming an insulating film and forming a plurality of contact holes for electrical connection with the lower electrode together with a plurality of convex patterns on the pixel portion; and a reflective pixel electrode comprising a reflective film on the pixel portion And a sixth step of forming the structure.

Also, the manufacturing method of the reflective liquid crystal display device of the present invention includes a pair of substrates and a liquid crystal layer interposed between the pair of substrates, and the surface of one of the pair of substrates is formed on one surface. A method of manufacturing a reflective liquid crystal display device in which an insulating layer having projections and depressions and a pixel electrode that covers a part of the insulating layer and that has projections and depressions on the surface and reflects light are formed on the substrate. a first step of forming a gate electrode and a gate wiring made of a conductive film, an insulating film made of SiN or SiO _2, a second step of forming a plurality of convex patterns in the pixel region, SiN or SiO _2, etc. A third step of sequentially forming a semiconductor active film and an ohmic film made of Si, a fourth step of forming a source electrode, a source wiring, and a drain electrode made of a conductive film, and a first step made of an organic resin. 1 A fifth step of forming a plurality of contact holes for electrical connection with the lower electrode together with a plurality of convex patterns on the pixel portion, and a concavo-convex shape formed on the pixel portion. A second interlayer insulating film made of an organic resin is further formed so as to be smooth, a sixth step of forming a plurality of contact holes for electrical connection with the lower electrode, and a reflection film formed on the pixel portion And a seventh step of forming a reflective pixel electrode.

Also, the manufacturing method of the reflective liquid crystal display device of the present invention includes a pair of substrates and a liquid crystal layer interposed between the pair of substrates, and the surface of one of the pair of substrates is formed on one surface. A method of manufacturing a reflective liquid crystal display device in which an insulating layer having projections and depressions and a pixel electrode that covers a part of the insulating layer and that has projections and depressions on the surface and reflects light are formed on the substrate. a first step of forming a gate electrode and a gate wiring made of a conductive film, an insulating film made of SiN or SiO _2, a second step of forming a plurality of convex patterns in the pixel region, SiN or SiO _2, etc. A third step of sequentially forming a gate insulating film made of Si, a semiconductor active film made of Si or the like, and an ohmic film, a fourth step of forming a source electrode made of a conductive film, a source wiring and a drain electrode, and a photosensitive organic resin Na Forming a plurality of concave patterns in the pixel region , and simultaneously forming a plurality of concave regions on the surface other than the concave pattern of the first interlayer insulating film made of the photosensitive organic resin. A fifth step of forming a concave recess and forming a plurality of contact holes for electrical connection with the lower electrode; and a sixth step of forming a reflective pixel electrode made of a reflective film in the pixel portion. It is characterized by that.

Also, the manufacturing method of the reflective liquid crystal display device of the present invention includes a pair of substrates and a liquid crystal layer interposed between the pair of substrates, and at least on one of the pair of substrates. A method of manufacturing a reflective liquid crystal display device, comprising: an insulating layer having irregularities on a surface; and a pixel electrode that covers at least a part of the insulating layer and that has irregularities on the surface and reflects light. A first step of forming a gate electrode and a gate wiring made of a conductive film, a second step of forming an insulating film made of SiN or SiO ₂ and forming a plurality of convex patterns in the pixel region; Alternatively, a third step of sequentially forming a gate insulating film made of SiO ₂ or the like, a semiconductor active film made of Si or the like and an ohmic film, and a fourth step of forming a source electrode, a source wiring and a drain electrode made of a conductive film A first interlayer insulating film made of a photosensitive organic resin is formed, and a plurality of concave patterns are formed in the pixel region , and at the same time, other than the concave pattern of the first interlayer insulating film made of the photosensitive organic resin. A fifth step of forming a plurality of concave depressions in a flat area on the surface and forming a plurality of contact holes for electrical connection with the lower electrode, and smoothing the uneven shape formed in the pixel portion In addition, a second interlayer insulating film made of an organic resin and a sixth step of forming a plurality of contact holes for electrical connection with the lower electrode, and a reflective pixel made of a reflective film in the pixel portion And a seventh step of forming an electrode.

Also, the manufacturing method of the reflective liquid crystal display device of the present invention includes a pair of substrates and a liquid crystal layer interposed between the pair of substrates, and the surface of one of the pair of substrates is formed on one surface. A method of manufacturing a liquid crystal display device having a reflective display portion in which an insulating layer having projections and depressions and a pixel electrode that covers a part of the insulating layer and has projections and depressions on the surface to reflect light are formed. A first step of forming a gate electrode and a gate wiring made of a conductive film on the substrate; a second step of forming an insulating film made of SiN or SiO ₂ and forming a plurality of convex patterns in the pixel region ; Alternatively, a third step of sequentially forming a gate insulating film made of SiO ₂ or the like, a semiconductor active film made of Si or the like, and an ohmic film, a fourth step of forming a source electrode, a source wiring, and a drain electrode made of a conductive film, Tree Forming a first interlayer insulating film made of fat, the first interlayer insulating film made of the fifth step and further the organic resin by using a different mask pattern for forming a concave shape of a plurality of patterns in the pixel portion A sixth step of forming a plurality of concave depressions in a flat region on the surface other than the plurality of concave patterns and forming a plurality of contact holes for electrical connection with the lower electrode, and reflecting to the pixel portion And a seventh step of forming a reflective pixel electrode made of a film.

Also, the manufacturing method of the reflective liquid crystal display device of the present invention includes a pair of substrates and a liquid crystal layer interposed between the pair of substrates, and the surface of one of the pair of substrates is formed on one surface. A method of manufacturing a liquid crystal display device having a reflective display portion in which an insulating layer having projections and depressions and a pixel electrode that covers a part of the insulating layer and has projections and depressions on the surface to reflect light are formed. A first step of forming a gate electrode and a gate wiring made of a conductive film on the substrate; a second step of forming an insulating film made of SiN or SiO ₂ and forming a plurality of convex patterns in the pixel region ; Alternatively, a third step of sequentially forming a gate insulating film made of SiO ₂ or the like, a semiconductor active film made of Si or the like, and an ohmic film, a fourth step of forming a source electrode, a source wiring, and a drain electrode made of a conductive film, Tree Forming a first interlayer insulating film made of fat, the first interlayer insulating film made of the fifth step and further the organic resin by using a different mask pattern for forming a concave shape of a plurality of patterns in the pixel portion A sixth step of forming a plurality of concave depressions in a flat region on the surface other than the plurality of concave patterns and forming a plurality of contact holes for electrical connection with the lower electrode, and forming in the pixel portion Forming a second interlayer insulating film made of an organic resin so as to make the uneven shape smooth, and forming a plurality of contact holes for electrical connection with the lower electrode; and a pixel portion And an eighth step of forming a reflective pixel electrode made of a reflective film.

The reflection type liquid crystal display equipment of the present invention includes a pair of substrates, seen including a liquid crystal layer interposed between the pair of substrates, one of the pair of substrates, a pixel portion on one of the substrates surface covering the concave-convex shape of the insulating layer and the insulating layer having an uneven shape, a liquid crystal display equipment having a reflective display portion and a pixel electrode for reflecting light is formed, the one on the board A gate electrode and a gate wiring made of a conductive film formed on the first substrate, a first convex pattern made of SiN or SiO ₂ formed on the one substrate , the gate electrode, the gate wiring, and the first wiring A gate insulating film made of SiN or SiO ₂ formed so as to cover the convex pattern, a semiconductor active film made of Si formed to face the gate electrode through the gate insulating film, and the semiconductor On the active film A source electrode, a source wiring, and a drain electrode made of a conductive film formed so as to be connected to the semiconductor active film via the ohmic contact film and the ohmic contact film; A first interlayer insulating film made of an organic resin having a plurality of concave patterns and a plurality of contact holes for electrical connection with the drain electrode, the first convex pattern and the concave shape A reflective display unit comprising a reflective pixel electrode made of a reflective film formed on the first interlayer insulating film so as to cover the uneven shape formed by a plurality of patterns; Features.

Furthermore, the reflection type liquid crystal display equipment of the present invention includes a pair of substrates, seen including a liquid crystal layer interposed between the pair of substrates, one of the pair of substrates, a pixel portion on one of the substrates surface covering the concave-convex shape of the insulating layer and the insulating layer having an uneven shape, a liquid crystal display equipment having a reflective display portion and a pixel electrode for reflecting light is formed, the one on the board a gate electrode and a gate wire formed of a conductive film is formed, a first convex pattern composed of SiN or SiO ₂ is formed on the one substrate, and the gate electrode and the gate wiring the first A gate insulating film made of SiN or SiO ₂ formed so as to cover the convex pattern, a semiconductor active film made of Si formed to face the gate electrode through the gate insulating film, and the semiconductor Formed on active membrane A source electrode, a source wiring, and a drain electrode made of an ohmic contact film and a conductive film formed so as to be connected to the semiconductor active film through the ohmic contact film, and so as to cover them, A first interlayer insulating film made of an organic resin having a plurality of concave patterns and a plurality of contact holes for electrical connection with the drain electrode; and an organic resin covering the first interlayer insulating film A second interlayer insulating film having a contact hole formed so as to be continuous with the plurality of contact holes, the first convex pattern, and the concave shape for electrical connection with the drain electrode. A reflective pixel electrode made of a reflective film formed on the second interlayer insulating film so as to cover the uneven shape formed by a plurality of patterns; For example, the second interlayer insulating film is characterized by having a reflective display portion, characterized in that it is formed so as to smooth the uneven shape.

According to the present invention, the reflective pixel electrode has a surface corresponding to each pixel having a convex pattern formed on the first insulating film made of SiN or SiO ₂ and a concave shape formed on the interlayer insulating film made of organic resin. Alternatively, since the unevenness is formed from the convex pattern, it is possible to increase the intensity of light scattered in the direction of the observer with respect to the incident angle from any angle. Therefore, a reflective TFT-LCD or a partially reflective TFT-LCD reflecting plate having a high-quality display characteristic with a bright display panel and a high contrast ratio can be manufactured by a simple process. Further, since a flat area on the surface of the reflective pixel electrode can be reduced, a reflective TFT-LCD or a partial reflective TFT-LCD having a superior paper white property can be manufactured by a simple process.

12 is a cross-sectional view showing a method of manufacturing a TFT array substrate of a reflective liquid crystal display device according to Reference Example 1. FIG. 12 is a cross-sectional view showing a method of manufacturing a TFT array substrate of a reflective liquid crystal display device according to Reference Example 1. FIG. 12 is a cross-sectional view showing a method of manufacturing a TFT array substrate of a reflective liquid crystal display device according to Reference Example 1. FIG. 6 is a plan view of a TFT array substrate of a reflective liquid crystal display device according to Reference Example 1. FIG. It is a top view showing embodiment of the planar shape of the convex pattern formed in a 1st insulating film. It is a top view showing other embodiment of the planar shape of the convex pattern formed in a 1st insulating film. It is a figure which shows the scattered reflected light with respect to the incident light inclined 30 degrees from the perpendicular. It is a graph which shows the relationship between the scattering reflection angle with respect to the incident light inclined 30 degrees from the perpendicular, and a reflectance. 12 is a cross-sectional view showing a method of manufacturing a TFT array substrate of a reflective liquid crystal display device according to Reference Example 2. FIG. 12 is a cross-sectional view showing a method of manufacturing a TFT array substrate of a reflective liquid crystal display device according to Reference Example 2. FIG. It is sectional drawing which shows the manufacturing method of the TFT array substrate of the reflection type liquid crystal display device concerning Embodiment 3 of this invention. It is a top view of the TFT array board | substrate of the reflection type liquid crystal display device concerning Embodiment 3 of this invention. It is sectional drawing which shows the manufacturing method of the TFT array substrate of the reflection type liquid crystal display device concerning Embodiment 4 of this invention. It is sectional drawing which shows the manufacturing method of the TFT array substrate of the reflection type liquid crystal display device concerning Embodiment 4 of this invention. It is sectional drawing which shows the manufacturing method of the TFT array substrate of the reflection type liquid crystal display device concerning Embodiment 5 of this invention. It is sectional drawing which shows the manufacturing method of the TFT array substrate of the reflection type liquid crystal display device concerning Embodiment 5 of this invention. It is a top view of the TFT array substrate of the reflection type liquid crystal display device concerning Embodiment 5 of this invention. It is sectional drawing which shows the manufacturing method of the TFT array substrate of the reflection type liquid crystal display device concerning Embodiment 6 of this invention. It is a top view of the TFT array board | substrate of the reflection type liquid crystal display device concerning Embodiment 7 of this invention. It is a top view of the other TFT array substrate of the reflection type liquid crystal display device concerning Embodiment 7 of this invention. FIG. 10 is a plan view of still another TFT array substrate of a reflective liquid crystal display device according to Embodiment 7 of the present invention. It is a top view of the TFT array board | substrate of the reflection type liquid crystal display device concerning Embodiment 8 of this invention. It is a top view of the other TFT array substrate of the reflection type liquid crystal display device concerning Embodiment 8 of this invention. It is a top view of other TFT array substrate of the reflection type liquid crystal display device according to the eighth embodiment of the present invention. It is the figure which showed two-dimensionally the distribution of the scattered reflected light with respect to the incident light inclined 30 degrees from the perpendicular. It is a light intensity distribution figure which shows the reflective scattering characteristic with anisotropy in the Example of the pattern of FIG. FIG. 25 is a light intensity distribution diagram showing reflection / scattering characteristics having anisotropy in the embodiment of the pattern of FIG. 24. It is a light intensity distribution figure which shows the reflective scattering characteristic in case there is no convex pattern as the comparative example 2. It is explanatory drawing which shows the incident light and reflected light by the uneven | corrugated shape formed in the reflecting plate.

  Hereinafter, a method for producing a reflective liquid crystal display device of the present invention will be described with reference to the accompanying drawings.

Reference example 1
In the reflective liquid crystal display device according to Reference Example 1, a method of manufacturing a TFT substrate having a pixel electrode made of a reflective film having irregularities on the surface will be described with reference to FIGS. 1 to 3 are cross-sectional views showing a method of manufacturing a TFT array substrate of a reflective liquid crystal display device according to Reference Example 1, and FIG. 4 is a plan view of the TFT array substrate of the reflective liquid crystal display device according to Reference Example 1. . FIG. 1 shows a cross section of a pixel portion where a gate electrode portion, a crossing portion of a gate wiring and a source wiring (gate / source wiring crossing portion), a TFT portion, and a pixel electrode formed of a reflective film are formed. First, as shown in FIG. 1, a first metal thin film is formed on an insulating substrate 1 such as a glass substrate by a method such as sputtering, and then patterned using first photolithography to obtain a gate electrode. 2, a pattern of a gate wiring 3, an auxiliary capacitance electrode (wiring) 4 for forming an electric capacity, and a gate terminal portion 5 is formed. Examples of the first metal thin film include chromium (Cr), aluminum (Al), molybdenum (Mo), tantalum (Ta), titanium (Ti), tungsten (W), copper (Cu), etc. An alloy or the like to which an impurity is added can be used. Moreover, a laminated film in which these metals or alloys are laminated can be used. The film thickness is preferably 100 to 500 nm. As a preferred embodiment, a Cr film having a thickness of 200 nm is formed, and then wet etching is performed using a known chemical solution containing cerium ammonium nitrate and perchloric acid, and the pattern shown in FIG. Formed.

Next, as shown in FIG. 1B, the first insulating film 6 is formed to a thickness of about 50 to 400 nm by using plasma CVD (Chemical Vapor Deposition). As the first insulating film 6, SiN, SiO ₂ can be used, or these multilayer films. As a preferred example, a SiN film of 300 nm was formed here. Then, a first convex pattern 7 is formed in the pixel region using second photolithography. The planar shape of the first convex pattern 7 is shown in FIG. 5A and FIG. 5B as a circle or a polygon close to a circle, or in FIG. 6A and FIG. 6B. Such as an ellipse or a polygon close to an ellipse. Further, the size is not limited to one type, and may be a plurality of types. These shapes can be appropriately set so that desired scattering reflection characteristics can be obtained. As a preferred embodiment, a circular first convex pattern 7 having a diameter of about 3 to 10 μm is randomly formed here to obtain the pattern configuration shown in FIG. The etching for forming the first convex pattern 7 used a dry etching method using a known gas composition, for example, a mixed gas of SF ₆ and O ₂ or a mixed gas of CF ₄ and O ₂ .

Next, as shown in FIG. 2A, the second insulating film 8, the semiconductor active film 9, and the ohmic contact film 10 are successively formed using plasma CVD. The second insulating film 8 is SiN or SiO ₂ having a thickness of 50 to 400 nm, and the semiconductor active film 9 is amorphous silicon (a-Si) or polysilicon (p-Si) having a thickness of 100 to 250 nm. As the film and the ohmic contact film 10, an n + a-Si film in which silicon having a thickness of about 20 to 70 nm is doped with a small amount of phosphorus (P) can be used. As a preferred embodiment, here, a second insulating film 8 is a 100 nm thick SiN film, a semiconductor active film 9 is a 150 nm thick a-Si film, and a 30 nm thick n + a-Si film is continuously formed. After the film formation, the pattern of the TFT part and the gate / source wiring intersection part was formed as shown in FIG. 2A by using the third photolithography. For the etching of the n + a-Si film and the a-Si film, a known dry etching method was used as described above.

  Next, a second metal thin film is formed by a method such as sputtering. As the second metal thin film, for example, Cr, Mo, Ta, Ti, W, or an alloy obtained by adding a small amount of impurities to these substances can be used. Further, when using a low resistance material such as Al or Cu, in order to obtain good electrical contact characteristics with the n + a-Si film which is the lower ohmic contact film 10, the above-mentioned Cr, Mo, Ta, Ti, A laminated film having a substance such as W as a lower layer is preferable. The thickness of the second metal thin film is preferably 100 to 500 nm. As a preferred embodiment, here, a Cr film having a thickness of 200 nm was formed and patterned using the fourth photolithography to form the source wiring 11, the source electrode 12 and the drain electrode 13 of the TFT portion. The Cr film was wet-etched using a known chemical solution containing cerium ammonium nitrate and perchloric acid. As a result, the pattern shown in FIG. 2B is formed.

  Next, a first interlayer insulating film 15 made of an organic resin is formed with a thickness of about 3.0 to 4.0 μm. The organic resin material and film thickness are preferably set to conditions such that the surface after formation is substantially flat. Formation of an interlayer insulating film made of an organic resin is performed by, for example, transferring a layered organic resin on a base film made of PET (polyethylene terephthalate) to a substrate and then removing the base film or forming an organic layer from a nozzle. For example, a method in which a resin is discharged onto a substrate and applied using a spin coating method can be used. As the organic resin for forming the interlayer insulating film, a photosensitive or non-photosensitive resin can be used. However, if a photosensitive resin is used, there is no need to newly perform patterning using a photoresist pattern. Is preferable because it can be simplified. As such an organic resin, for example, known JSR PC335 or PC405 can be used. As a preferred embodiment, JSR PC335 is applied and formed to a thickness of 3.2 to 3.9 μm using a spin coat method, and the gate terminal portion is formed using a fifth photolithography. A plurality of second convex patterns 18 are formed in the contact hole 16, the contact hole (not shown) of the source terminal portion, the contact hole 17 between the pixel / drain electrodes, and the pixel region. As a result, the pattern shown in FIG. 3A is formed. Here, the plurality of second convex patterns 18 may be formed in the same manner as the first convex pattern 7, and the diameter is preferably about 5 to 50 μm, and the size is also limited to one type. It is preferable that a plurality of types are randomly arranged. Further, as shown in FIG. 4, in the region 19 where the organic resin film other than the second convex pattern 18 of the first interlayer insulating film 15 of the pixel portion is removed, the first insulating film 6 has the first thickness. It is preferable to adopt a planar arrangement in which a plurality of one convex pattern 7 exists. Thereby, even in the region 19 from which the organic resin film has been removed, the region that becomes flat due to the presence of the first convex pattern 7 of the first insulating film 6 can be reduced, so that the specular reflection component is small and the paper A reflective pixel electrode with excellent whiteness can be obtained.

  In this reference example, the first interlayer insulating film 15 is a single organic resin film. However, after the third insulating film made of SiN is formed to a thickness of about 10 to 150 nm using plasma CVD, for example. Alternatively, a two-layer structure in which an organic resin is formed with a film thickness of about 3.0 to 4.0 μm may be used. In this case, the channel portion 14 of the TFT can be prevented from being contaminated from the first interlayer insulating film 15, and the stability of the TFT characteristics can be improved.

  Next, a third metal thin film is formed by a method such as sputtering. Since the third metal thin film becomes the reflective pixel electrode 21 that also serves as the reflection plate of the pixel portion, it is preferable to use a substance having a high reflectance as much as possible. For example, Al, Ag having a reflectance characteristic of 90% or more with visible light having a wavelength of 550 nm, or an alloy obtained by adding a trace amount of impurities to these substances can be used. The film thickness is preferably about 50 to 400 nm, but in order to sufficiently prevent the disconnection failure at the step portion at the uneven portion of the pixel portion and sufficiently exhibit the excellent reflection characteristics inherent in the substance, the film thickness is set to 100 nm or more. Is more preferable. Further, in order to improve the adhesion and the electrical contact characteristics with the lower metal thin film, a laminated structure in which a metal thin film such as Cr, Mo, Ta, Ti or W is provided in the lower layer may be adopted. As a preferred embodiment, after forming an Al film having a thickness of 300 nm, the pattern of the gate terminal pad 20, the source terminal pad (not shown), and the reflective pixel electrode 21 is formed by using sixth photolithography. Formed. As a result, the pattern shown in FIG. 3B is formed, and the fabrication of the TFT array substrate of the reflective liquid crystal display device according to Reference Example 1 is completed.

As shown in FIG. 7, with respect to the pixel reflection electrode 21 of the completed TFT array substrate, the scattering reflection characteristics when incident light 26 emitted from the light source 25 and inclined by 30 ° from the perpendicular is given ( Specifically, the scattering reflection angle θ and the reflectivity are shown as a result of measurement of the angle of inclination of the scattered reflected light 31 dispersed around the specular reflected light 30 inclined at 30 ° from the normal as the scattering reflection angle θ. A graph showing the relationship with R is shown in FIG. In FIG. 8, the characteristic curve of Reference Example 1 is indicated by I, the characteristic curve of Comparative Example 1 is indicated by II, and the curves I and II become closer to the specular reflection angle θ ₀ (= 30 °). The reflectance R increases. Comparative Example 1 shows the scattering reflection characteristics of the pixel reflection electrode of the conventional TFT array substrate in which the first convex pattern 7 is not formed. In the case of this reference example 1, in the area | region of scattering reflection angle (theta) = 10 degrees-50 degrees, compared with the comparative example 1, the reflectance was higher and it confirmed that it showed the outstanding scattering reflection characteristic.

  As described above, in Reference Example 1, the plurality of first convex patterns 7 are formed in the pixel region of the first insulating film 6 made of the SiN film, and further, the pixel portion of the first interlayer insulating film 15 is formed. In the region 19 on the pixel portion where the second convex pattern 18 is formed and the first interlayer insulating film 15 is removed, the first convex pattern 7 by the first insulating film 6 is exposed. Therefore, the first and second convex patterns 7 and 18 having different thicknesses are randomly arranged on the plane. As described above, the convex patterns having various thicknesses (heights) are randomly arranged on the plane, so that flat portions having the same height can be reduced, and a wide scattering reflection angle (for example, 0 to 0). The reflective pixel electrode 21 having excellent scattering reflection characteristics (paper white property) at about 50 ° can be manufactured by a manufacturing method with a small number of steps. Here, the second insulating film 8 is formed by smoothly changing the uniform thickness (height) of the first convex pattern 7 formed by the first insulating film 6 and scattered at the same height. The convex pattern 7 prevents a new flat surface (flat portion) from being formed. The new flat portion exhibits undesirable specular reflection characteristics.

  In the case where the convex pattern 7 has a shape whose height changes smoothly (for example, a conical shape), if the angle formed by the slope of the convex pattern 7 and the horizontal plane is γ, the reflective pixel shown in FIG. When incident light 26 inclined by α (for example, 30 °) from the normal toward the surface of the electrode 21 is reflected by the inclined surface of the convex pattern, the specular reflection light is inclined by α + 2γ from the normal, so that the scattering reflection characteristic is improved by 2γ. If you want to control the intensity of the reflected light with respect to the scattering angle using this characteristic, you can increase (or decrease) the convex part with a gradient of 1/2 the scattering angle you want to increase (or decrease). Good.

  In addition, since the insulating film at the TFT portion and the gate / source wiring intersection has a two-layer structure of the first insulating film 6 and the second insulating film 8, the lower gate electrode 2 and the gate wiring 3 due to foreign matter, defects, etc. And the upper layer source wiring 11, the source electrode 12, and the drain electrode 13 can be greatly reduced, and the yield can be improved. The present invention can also be applied to a partial reflection type liquid crystal display device.

Reference example 2
In the reflective liquid crystal display device according to Reference Example 2, a method for manufacturing a TFT substrate having reflective pixel electrodes having irregularities on the surface will be described with reference to FIGS. 9 to 10 are cross-sectional views showing a method of manufacturing a TFT array substrate of a reflective liquid crystal display device according to Reference Example 2, and the same parts as in Reference Example 1 are denoted by the same reference numerals. In the reference example 2, since the manufacturing method of FIGS. 1 to 2 in the reference example 1 is the same, the description thereof is omitted.

  In the example in Reference Example 2, as the first interlayer insulating film 15 made of an organic resin, JSR PC335 was applied and formed to a thickness of 3.2 to 3.9 μm using a spin coating method. 9 to 10, the fifth photolithography is used to form the contact hole 16 in the gate terminal portion, the contact hole (not shown) in the source terminal portion, the contact hole 17 between the pixel / drain electrodes, and the pixel. After the plurality of second convex patterns 18 are formed, a second interlayer insulating film 22 is formed. As the second interlayer insulating film 22, the same organic resin as that of the first interlayer insulating film 15 can be used. The surface of the second interlayer insulating film 22 is not flat, and a plurality of second convex patterns 18 formed in the pixel region of the first interlayer insulating film 15 and a plurality of pixels formed in the pixel region of the first insulating film 6 are formed. It is necessary to apply and form the first convex pattern 7 so as to leave the convex shape. For this reason, the organic resin film used for the second interlayer insulating film 22 uses a resin having a smaller film thickness and a smaller viscosity (viscosity) than the organic resin film used for the first interlayer insulating film 15. Is preferred. For example, an organic resin film having a viscosity of about 15 to 35 mPa · sec is used as the first interlayer insulating film 15, and an organic resin film having a viscosity of about 5 to 15 mPa · sec is used as the second interlayer insulating film 22. Can be used. As an example, as the first interlayer insulating film 15, a JSR PC335 having a viscosity of about 30 mPa · sec is applied with a film thickness of about 3.2 to 3.9 μm to form a pattern. As the second interlayer insulating film 22, JSR PC335 having a viscosity of about 10 mPa · sec was spin-coated with a film thickness of about 1.0 μm. Then, a contact hole 16 in the gate terminal portion, a contact hole in the source terminal portion (not shown), and a contact hole 17 between the pixel / drain electrodes were formed by using sixth photolithography. As described above, the second interlayer insulating film 22 forms a pattern that makes the uneven shape of the pixel portion smooth as shown in FIG. 9B.

  Finally, a third metal thin film is formed by the same method as in Reference Example 1 described above, and the gate terminal pad 20, the source terminal pad (not shown), and the reflective pixel electrode 21 are formed using seventh photolithography. A pattern was formed. Thus, the pattern shown in FIG. 10 is formed, and the fabrication of the TFT array substrate of the reflective liquid crystal display device according to Reference Example 2 is completed.

  As described above, in Reference Example 2, the first convex pattern 7 formed in the pixel region by the first insulating film 6 and the second convex shape formed in the pixel region by the first interlayer insulating film 15. Since the second interlayer insulating film 22 is further thinly applied on the uneven shape of the pattern 18, the uneven shape becomes smooth, and smooth scattering reflection characteristics without a sharp change (mirror reflection) in the reflection characteristics are obtained. Therefore, higher quality display characteristics can be obtained.

Embodiment 3
In the reflective liquid crystal display device according to the third embodiment of the present invention, a method of manufacturing a TFT substrate having a reflective pixel electrode having irregularities on the surface will be described with reference to FIG. FIG. 11 is a cross-sectional view showing a method of manufacturing a TFT array substrate of a reflective liquid crystal display device according to Embodiment 3, and the same parts as those in Reference Example 1 are denoted by the same reference numerals. In this Embodiment 3, since the manufacturing method to FIGS. 1-2 in the said reference example 1 is the same, description is abbreviate | omitted.

  After forming the pattern shown in FIG. 2B using the same process as described above, the first interlayer insulating film 15 made of an organic resin is formed in 3.0 to 4.4 as shown in FIG. 11A. It is formed with a film thickness of about 0 μm. The organic resin material and film thickness are preferably set to conditions such that the surface after formation is substantially flat. Formation of an interlayer insulating film made of an organic resin is performed by, for example, transferring a layered organic resin on a base film made of PET (polyethylene terephthalate) to a substrate and then removing the base film or forming an organic layer from a nozzle. For example, a method in which a resin film is discharged onto a substrate and applied using a spin coating method can be used. The interlayer insulating film can be photosensitive or non-photosensitive. However, if a photosensitive film is used, it is not necessary to newly pattern using a photoresist pattern, and the process can be simplified. It is preferable because it is possible. As such a photosensitive interlayer insulating film, for example, a known JSR PC335 or PC405 can be used. As a preferred embodiment, JSR PC335 is applied and formed to a thickness of 3.2 to 3.9 μm using a spin coat method, and the gate terminal portion is formed using a fifth photolithography. A contact hole 16, a contact hole (not shown) in the source terminal portion, a contact hole 17 between the pixel / drain electrodes, and a plurality of concave patterns 23 in the pixel portion were formed. The concave pattern 23 has a hole shape that reaches the second insulating film 8 below. Thus, the pattern shown in FIG. 11A is formed. Here, it is preferable that the plurality of concave patterns 23 have a diameter of about 5 to 50 μm, and the size is not limited to one type, and a plurality of types are preferably arranged at random. In addition, as shown in FIG. 12, it is preferable to adopt a planar arrangement in which a plurality of first convex patterns 7 of the first insulating film 6 exist in the region of the plurality of concave patterns 23 in the pixel portion. Thereby, even in the region 23 from which the first interlayer insulating film 15 has been removed, the region that becomes flat due to the presence of the convex pattern 7 of the first insulating film can be reduced, so that the specular reflection component is small and the paper It can be set as the reflecting plate excellent in white property.

  In this embodiment, since the pattern of the organic resin film formed in the pixel region is a hole-shaped concave pattern that is completely etched as described above, even if the exposure dose distribution is uneven in photolithography, the pattern is convex. Since the uneven distribution can be reduced as compared with the shape pattern, it is possible to suppress the uneven reflection characteristic display.

  In the present embodiment, the first interlayer insulating film 15 is a single organic resin film. However, for example, a third insulating film made of SiN is formed to a thickness of about 10 to 150 nm using plasma CVD. Then, it is good also as a 2 layer structure which formed the organic resin film with the film thickness of about 3.0-4.0 micrometers. In this case, the channel portion 14 of the TFT can be prevented from being contaminated from the first interlayer insulating film 15, and the stability of the TFT characteristics can be improved.

  Next, a third metal thin film is formed by a method such as sputtering. Since the third metal thin film serves as the reflective pixel electrode 21 that also serves as a reflection plate of the pixel portion, it is preferable to use a material having as high a reflectance as possible. For example, Al, Ag having a reflectance characteristic of 90% or more with visible light having a wavelength of 550 nm, or an alloy obtained by adding a trace amount of impurities to these substances can be used. The film thickness is preferably about 50 to 400 nm, but in order to sufficiently prevent the disconnection failure at the step portion in the uneven portion of the pixel portion and sufficiently exhibit the excellent reflection characteristics inherent in the substance, it is preferably set to 100 nm or more. More preferred. Further, in order to improve the adhesion and electrical contact characteristics with the lower metal thin film, a laminated structure in which a metal thin film such as Cr, Mo, Ta, Ti or W is provided in the lower layer may be adopted. As a preferred embodiment, an Al film having a thickness of 300 nm is formed here, and a pattern of a gate terminal pad 20, a source terminal pad (not shown), and a reflective pixel electrode 21 is formed by using sixth photolithography. did. Thus, the pattern shown in FIG. 11B is formed, and the fabrication of the TFT array substrate of the reflective liquid crystal display device according to the third embodiment of the present invention is completed.

  As described above, in this embodiment, the plurality of convex patterns 7 are formed in the pixel region of the first insulating film made of the SiN film, and the concave pattern is formed in the pixel portion of the first interlayer insulating film 15. 23, and the first convex pattern 7 formed by the first insulating film 6 is exposed in the region (concave pattern 23) on the pixel portion from which the first interlayer insulating film 15 has been removed. Therefore, the first convex patterns 7 having different thicknesses and the convex portions of the first interlayer insulating film 15 (flat portions left after the formation of the concave patterns 23) are randomly arranged on the plane. Since convex patterns of various thicknesses (heights) are randomly arranged on the plane in this way, flat portions having the same height can be reduced, and excellent scattering reflection characteristics (paper white The reflective pixel electrode 21 having the characteristics can be manufactured by a manufacturing method with a small number of steps. Here, the second insulating film 8 is formed by smoothly changing the uniform thickness (height) of the first convex pattern 7 formed by the first insulating film 6 and scattered at the same height. The convex pattern 7 prevents a new flat surface (flat portion) from being formed. The new flat portion exhibits undesirable specular reflection characteristics. In addition, since the insulating film at the TFT portion and the gate / source wiring intersection has a two-layer structure of the first insulating film 6 and the second insulating film 8, the lower gate electrode 2 and the gate wiring 3 due to foreign matter, defects, etc. And the upper layer source wiring 11, source electrode 12, and drain electrode 13 can be greatly reduced, and the yield can be improved.

Embodiment 4
In the reflective liquid crystal display device according to the fourth embodiment of the present invention, a method for manufacturing a TFT substrate having a reflective pixel electrode having irregularities on the surface will be described with reference to FIGS. 13 to 14 are cross-sectional views showing a method of manufacturing a TFT array substrate of a reflective liquid crystal display device according to the fourth embodiment. The same parts as those in the third embodiment are denoted by the same reference numerals. Moreover, in this Embodiment 4, since the manufacturing method to FIGS. 1-2 in the said reference example 1 is the same, description is abbreviate | omitted.

  In a preferred example of the fourth embodiment, as a first interlayer insulating film 15 made of an organic resin, JSR-made PC335 is applied so as to have a film thickness of 3.2 to 3.9 μm using a spin coat method. Film formation is performed, and contact holes 16 in the gate terminal portion, contact holes in the source terminal portion (not shown), contact holes 17 between the pixel / drain electrodes, and a plurality of concave patterns 23 in the pixel portion are formed using fifth photolithography. Is formed (FIG. 13A). Thereafter, the second interlayer insulating film 22 is formed. As the second interlayer insulating film 22, the same organic resin as that of the first interlayer insulating film 15 can be used. The surface of the second interlayer insulating film 22 is not flat, and a plurality of concave patterns 23 formed in the pixel region of the first interlayer insulating film 15 and a plurality of first patterns formed in the pixel region of the first insulating film 6 are formed. It is necessary to apply and form so that the convex shape of the convex pattern 7 remains. For this reason, the organic resin film used for the second interlayer insulating film 22 is made of a resin having a smaller film thickness and a smaller viscosity (viscosity) than the organic resin film used for the first interlayer insulating film 15. Is preferred. For example, the first interlayer insulating film 15 is an organic resin film having a viscosity of about 15 to 35 mPa · sec, and the second interlayer insulating film 22 is an organic resin film having a viscosity of about 5 to 15 mPa · sec. Can be used. As a preferred embodiment, here, as the first interlayer insulating film 15, JSR PC335 having a viscosity of about 30 mPa · sec is applied and patterned with a film thickness of about 3.2 to 3.9 μm, As the interlayer insulating film 22, JSR PC335 having a viscosity of about 10 mPa · sec was spin-coated with a thickness of about 1.0 μm. Then, a contact hole 16 in the gate terminal portion, a contact hole in the source terminal portion (not shown), and a contact hole 17 between the pixel / drain electrodes were formed by using sixth photolithography. As described above, the second interlayer insulating film 22 forms a pattern that makes the uneven shape of the pixel portion smooth as shown in FIG.

  Finally, a third metal thin film is formed by the same method as in the third embodiment, and the gate terminal pad 20, the source terminal pad (not shown), and the reflective pixel electrode 21 are used by using the seventh photolithography. Pattern was formed. Thus, the pattern shown in FIG. 14 is formed, and the fabrication of the TFT array substrate of the reflective liquid crystal display device according to the fourth embodiment of the present invention is completed.

  As described above, in the fourth embodiment, the first convex pattern 7 formed in the pixel region by the first insulating film 6 and the concave pattern 23 formed in the pixel region by the first interlayer insulating film 15. Since the second interlayer insulating film 22 is further thinly applied on the concavo-convex shape formed by the step, the concavo-convex shape becomes smooth, and a smooth scattering reflection characteristic without a sharp change (mirror reflection) in the reflection characteristic is obtained. Therefore, higher quality display characteristics can be obtained.

Embodiment 5
In the reflective liquid crystal display device according to the fifth embodiment of the present invention, a method of manufacturing a TFT substrate having a reflective pixel electrode having irregularities on the surface will be described with reference to FIGS. 15 to 16 are cross-sectional views showing a method of manufacturing a TFT array substrate of a reflective liquid crystal display device according to the fifth embodiment, and the same parts as those in the third embodiment are denoted by the same reference numerals. In the fifth embodiment, the manufacturing method from FIG. 1 to FIG.

After the pattern shown in FIG. 15A is formed using the same process as in the third embodiment described above, the pattern other than the concave pattern of the first interlayer insulating film 15 made of organic resin is formed by the sixth photolithography. A plurality of concave depressions 24 are formed in a flat region. The planar shape of the concave recess 24 may be a circle or a nearly polygon as shown in FIGS. 5 (a) and 5 (b), or an ellipse as shown in FIGS. 6 (a) and 6 (b). Or it can be a polygon close to an ellipse. Further, the size is not limited to one type, and may be a plurality of types. These shapes can be appropriately set so as to obtain desired scattering reflection characteristics. As a preferred embodiment, a circular concave recess 24 having a diameter of about 3 to 30 μm is randomly formed here to obtain a planar pattern configuration shown in FIG. As a method for forming the concave recess 24, in this embodiment, a photoresist is applied, a resist pattern is formed using a photolithography method, and CF ₄ or SF ₆ gas is mixed with a known O ₂ gas or O ₂ gas. A dry etching method using a gas was used. After etching the first interlayer insulating film 15 to a depth of about 0.1 to 1.0 μm, which is shallower than its thickness, the photoresist is removed to form the pattern shown in FIG.

  Finally, a third metal thin film is formed by the same method as in the third embodiment, and the gate terminal pad 20, the source terminal pad (not shown), and the reflective pixel electrode 21 are used by using the seventh photolithography. Pattern was formed. Thus, the pattern shown in FIG. 16 is formed, and the fabrication of the TFT array substrate of the reflective liquid crystal display device according to the fifth embodiment of the present invention is completed.

  As described above, in the fifth embodiment, a plurality of first convex patterns 7 formed in the pixel region by the first insulating film 6 and a plurality of holes in the pixel region of the first interlayer insulating film 15 are formed. Since the plurality of concave dents 24 are formed in the flat part in addition to the concave pattern 23, the reflective pixel electrode 21 having excellent flat reflection characteristics with few flat parts can be manufactured by a simple process. In addition, since the insulating film at the TFT portion and the gate / source wiring intersection has a two-layer structure of the first insulating film 6 and the second insulating film 8, the lower gate electrode 2 and the gate wiring 3 due to foreign matter, defects, etc. And the upper layer source wiring 11, the source electrode 12, and the drain electrode 13 can be greatly reduced, and the yield can be improved.

  In the fifth embodiment, the concave recess 24 formed in the flat portion of the first interlayer insulating film 15 is formed by sixth photolithography using a photoresist and a known dry etching method. For example, JSR PC335, which is a photosensitive organic resin film, is applied and formed as the first interlayer insulating film 15 to have a film thickness of 3.2 to 3.9 μm using the spin coat method, and the fifth photo A pixel that reaches the contact hole 16 in the gate terminal portion, the contact hole (not shown) in the source terminal portion, the contact hole 17 between the pixel / drain electrodes, and the second insulating film 18 below by using a halftone exposure process for lithography. The concave recesses 24 may be formed simultaneously with the formation of the plurality of concave patterns 23. In this case, as the photomask used for the fifth photolithography, a pattern in which the concave dent 24 is formed as a pattern for reducing exposure light by providing a slit pattern or a UV absorption layer can be used. As a result, the concave recess 24 is subjected to intermediate exposure with a reduced exposure amount. Therefore, the fifth photolithography is performed only once, whereby the contact hole 16 in the gate terminal and the contact hole in the source terminal (see FIG. (Not shown), the contact hole 17 between the pixel / drain electrodes, the plurality of concave patterns 23 and the concave depressions 24 in the pixel portion can be formed at a time, so that the sixth photolithography step described above can be omitted.

Embodiment 6
In the reflective liquid crystal display device according to the sixth embodiment of the present invention, a method of manufacturing a TFT substrate having a reflective pixel electrode having irregularities on the surface will be described with reference to FIG. FIG. 18 is a cross-sectional view illustrating a method of manufacturing a TFT array substrate of a reflective liquid crystal display device according to the sixth embodiment, and a part of the reference examples 1 and 5 is denoted by the same reference numerals. In the sixth embodiment, since the manufacturing method up to FIG. 15 in the fifth embodiment is the same, the description thereof is omitted.

  In a preferred example of the sixth embodiment, as the first interlayer insulating film 15 made of an organic resin, JSR PC335 is applied to have a film thickness of 3.2 to 3.9 μm using a spin coating method. Then, using a fifth photolithography, a contact hole 16 in the gate terminal portion, a contact hole in the source terminal portion (not shown), a contact hole 17 between the pixel / drain electrodes, and a plurality of concave patterns in the pixel portion 23 and a plurality of concave indentations 24 are formed. Next, after the pattern shown in FIG. 15B is formed, a second interlayer insulating film 22 is formed as shown in FIG. As the second interlayer insulating film 22, the same organic resin as that of the first interlayer insulating film 15 can be used. The surface of the second interlayer insulating film 22 is not flat, and a plurality of concave patterns 23 and a plurality of concave depressions 24 formed in the pixel region of the first interlayer insulating film 15 and a pixel region of the first insulating film 6 are formed. It is necessary to apply and form so that the convex shape of the convex pattern 7 is left. For this reason, the organic resin film used for the second interlayer insulating film 22 is made of a resin having a smaller film thickness and a smaller viscosity (viscosity) than the organic resin film used for the first interlayer insulating film 15. It is preferable. For example, the first interlayer insulating film 15 is an organic resin film having a viscosity of about 15 to 35 mPa · sec, and the second interlayer insulating film 22 is an organic resin film having a viscosity of about 5 to 15 mPa · sec. Can be used. As a preferred embodiment, here, as the first interlayer insulating film 15, JSR PC335 having a viscosity of about 30 mPa · sec is applied and patterned with a film thickness of about 3.2 to 3.9 μm, As the interlayer insulating film 22, JSR PC335 having a viscosity of about 10 mPa · sec was spin-coated with a thickness of about 1.0 μm. Then, a contact hole 16 in the gate terminal portion, a contact hole in the source terminal portion (not shown), and a contact hole 17 between the pixel / drain electrodes were formed using seventh photolithography. After that, a third metal thin film is formed by the same method as that of the above-described fifth embodiment, and the gate terminal pad 20, the source terminal pad (not shown), and the reflective pixel electrode 21 are used by using the eighth photolithography. Pattern was formed. Thus, the pattern shown in FIG. 18 is formed, and the fabrication of the TFT array substrate of the reflective liquid crystal display device according to the sixth embodiment of the present invention is completed.

  As described above, in the sixth embodiment, the hole-like concave pattern 23 is formed in the pixel region of the first convex pattern 7 and the first interlayer insulating film 15 formed in the pixel region by the first insulating film 6. And the concave recess 24 are formed, and the second interlayer insulating film 22 is further thinly applied on the concave and convex shapes, so that the concave and convex shapes become smooth and the reflection characteristics change rapidly (specular reflection). Therefore, it is possible to obtain smooth display characteristics with higher quality.

Embodiment 7
In the above-described fifth and sixth embodiments, the planar shape of the plurality of concave depressions 24 formed in the first interlayer insulating film 15 made of organic resin is configured to be a circle, an ellipse, or a polygon close to these. However, the present invention is not limited thereto, and may be formed in a stripe shape or a wave shape having a plurality of peaks and valleys. Further, the shape and size are not limited to one type, and may be a plurality of types. As a preferred embodiment, a concave recess 24 having a planar shape as shown in FIGS. The X-axis direction represents the horizontal direction when the LCD is in use. In this case, a scattering reflection characteristic having anisotropy in the vertical direction of the LCD can be realized. In a reflective LCD, since the direction of incident light has many components from above, the reflected light tends to go downward, and anisotropic reflection characteristics are desirable to correct this tendency. The stripe direction and wave shape are not limited to those shown in FIGS. 19 to 21 and can be set as appropriate according to the required scattering reflection characteristics.

Embodiment 8
In the reference examples 1 to 3 and the embodiments 4 to 7 of the present invention described so far, the first convex pattern 7 formed in the pixel region of the first insulating film 6 using the second photolithography. The planar shape of FIG. 5A is a circle or a polygon close to a circle as shown in FIG. 5A and FIG. 5B, or an ellipse as shown in FIG. 6A and FIG. However, the present invention is not limited thereto, and may be formed in a stripe shape or a wave shape having a plurality of peaks and valleys. Further, the shape and size are not limited to one type, and may be a plurality of types. As a preferred embodiment, a first convex pattern 7 having a planar shape as shown in FIGS. The etching for forming the first convex pattern 7 used a dry etching method using a known gas composition, for example, a mixed gas of SF ₆ and O ₂ or a mixed gas of CF ₄ and O ₂ .

  As shown in FIG. 25, when incident light 20 emitted from the light source 25 and inclined by 30 ° from the perpendicular is given to the pixel reflection electrode 21 of the completed TFT array substrate, the reflected light 29 The scattered reflected light intensity distribution 32 spreads two-dimensionally.

22 to 24, the X-axis direction represents the horizontal direction when the LCD is used. For example, in the embodiment of the pattern shown in FIG. 22, the horizontal direction (90 ° -270 ° direction) and the vertical direction as shown in FIG. 26 by the edge portion in the X axis direction and the edge portion in the Y axis direction of the first convex pattern 7. Wide reflection and scattering characteristics having anisotropy in the direction (0 ° -180 ° direction) were obtained. For example, in FIG. 26, the scattered reflected light intensity distribution 32 that appears below the incident light 26 has five regions, that is, A ₁ (0.857 to 2.018), A ₂ (2.018 to 3.759), A ₃ (3.759 to 6.081), A ₄ (6.081 to 7.242), A ₅ (7.242 to 9.564) (all are relative values). On the other hand, in the embodiment of the zigzag pattern having an angle of 45 ° in FIG. 24, for example, due to the shape of the first convex pattern 7, the diagonal direction of the LCD panel (45 ° -225 °, And wide reflection / scattering characteristics having anisotropy in the 135 ° -315 ° direction). For example, in FIG. 27, the scattered reflected light intensity distribution 32 that appears below the incident light 26 has six regions, that is, B ₁ (1.00 to 2.00), B ₂ (2.00 to 3.00), B ₃ (3.00 to 4.00), B ₄ (4.00 to 6.00), B ₅ (6.00 to 8.00), B ₆ (8.00 to 10.00) (all Relative value).

  In reflective LCDs, as the direction of incident light has many components from above, the reflected light tends to move downward, and in general, there are many eye movements in the vertical direction with respect to the monitor. It is desirable to have a wide anisotropic reflection characteristic in the vertical direction. In the case of a relatively large LCD panel, the peripheral dimming tends to be noticeable at the four corners of the panel. To correct this tendency, anisotropic reflection characteristics can be provided in an oblique direction as necessary. desirable.

On the other hand, as Comparative Example 2, when there is no convex pattern 7, only a narrow reflection / scattering characteristic can be obtained. For example, in FIG. 28, the scattered reflected light intensity distribution 32 that appears below the incident light 26 has four regions, namely C ₁ (3.59 to 8.99), C ₂ (8.99 to 19.77), C ₃ (19.77 to 23.36) and C ₄ (23.36 to 28.27) (both are relative values).

The stripe direction and wave shape are not limited to those shown in FIGS. 22 to 24, and can be set as appropriate according to the required scattering reflection characteristics. In this case, since the stripe-shaped or wave-shaped convex pattern is formed on the SiN or SiO ₂ film by using the dry etching method, it is possible to perform patterning with high accuracy and to precisely control desired anisotropic scattering reflection characteristics. it can.

1 Insulating substrate 2 Gate electrode 3 Gate wiring 4 Auxiliary capacitance wiring (electrode)
DESCRIPTION OF SYMBOLS 5 Gate terminal part 6 1st insulating film 7 1st convex pattern of 1st insulating film 8 2nd insulating film 9 Semiconductor active film 10 Ohmic contact film 11 Source wiring 12 Source electrode 13 Drain electrode 14 Channel of TFT Part 15 First interlayer insulating film 16 Contact hole 17 in gate terminal part Contact hole 18 between pixel / drain electrodes Second convex pattern 19 in first interlayer insulating film Region where first interlayer insulating film is removed 20 Gate terminal pad 21 Reflective pixel electrode 22 Second interlayer insulating film 23 Recessed pattern 24 formed in the first interlayer insulating film Recessed recess 25 formed in the flat region of the first interlayer insulating film Light source 26 Directly Incident light 27 Indirect incident light 28 Observer 29 Reflected light

Claims (18)

A pair of substrates and a liquid crystal layer interposed between the pair of substrates are included. An insulating layer having an uneven surface on one of the pair of substrates and a part of the insulating layer are provided. A method of manufacturing a liquid crystal display device having a reflective display portion in which a pixel electrode that has irregularities on a cover surface and reflects light is formed, wherein a gate electrode and a gate wiring made of a conductive film are formed on the substrate A first step of forming;
A second step of forming an insulating film made of SiN or SiO ₂ and forming a plurality of convex patterns in the pixel region;
A third step of sequentially forming a gate insulating film made of SiN or SiO _2, a semiconductor active film made of Si, etc. and an ohmic film;
A fourth step of forming a source electrode made of a conductive film, a source wiring, and a drain electrode;
A fifth step of forming a first interlayer insulating film made of an organic resin, and forming a plurality of concave holes in the pixel portion and a plurality of contact holes for electrical connection with the lower electrode;
A method of manufacturing a liquid crystal display device having a reflective display portion, which includes a sixth step of forming a reflective pixel electrode made of a reflective film in the pixel portion. A pair of substrates and a liquid crystal layer interposed between the pair of substrates are included. An insulating layer having an uneven surface on one of the pair of substrates and a part of the insulating layer are provided. A method of manufacturing a liquid crystal display device having a reflective display portion in which a pixel electrode that has irregularities on a cover surface and reflects light is formed, wherein a gate electrode and a gate wiring made of a conductive film are formed on the substrate A first step of forming;
A second step of forming an insulating film made of SiN or SiO ₂ and forming a plurality of convex patterns in the pixel region;
A third step of sequentially forming a gate insulating film made of SiN or SiO _2, a semiconductor active film made of Si, etc. and an ohmic film;
A fourth step of forming a source electrode made of a conductive film, a source wiring, and a drain electrode;
A fifth step of forming a first interlayer insulating film made of an organic resin, and forming a plurality of concave holes in the pixel portion and a plurality of contact holes for electrical connection with the lower electrode;
A sixth step of forming a second interlayer insulating film made of an organic resin so as to smooth the uneven shape formed in the pixel portion and forming a plurality of contact holes for electrical connection with the lower electrode When,
A method of manufacturing a liquid crystal display device having a reflective display portion, which includes a seventh step of forming a reflective pixel electrode made of a reflective film in the pixel portion. In the fifth step, the portion where the first interlayer insulating film is removed to form a plurality of concave patterns in the pixel portion of the first interlayer insulating film made of organic resin in the second step, _3. The method of manufacturing a liquid crystal display device having a reflective display unit according to claim 1, wherein there are a plurality of regions where a plurality of convex patterns are provided in a pixel region of an insulating film made of SiN or SiO2. 4. The reflection according to claim 1, wherein the plurality of convex patterns formed in the pixel region of the insulating film made of SiN or SiO ₂ is a circle, a polygon close to a circle, an ellipse, or a polygon close to an ellipse. A method of manufacturing a liquid crystal display device having a mold display unit. Preparation of a liquid crystal display device having a reflective display portion according to claim 1, wherein a plurality of convex patterns are stripes to be formed in the pixel region of the insulating film made of the SiN or SiO _2. A pair of substrates and a liquid crystal layer interposed between the pair of substrates are included. An insulating layer having an uneven surface on one of the pair of substrates and a part of the insulating layer are provided. A method of manufacturing a liquid crystal display device having a reflective display portion in which a pixel electrode that has irregularities on a cover surface and reflects light is formed, wherein a gate electrode and a gate wiring made of a conductive film are formed on the substrate A first step of forming;
A second step of forming an insulating film made of SiN or SiO ₂ and forming a plurality of convex patterns in the pixel region ;
A third step of sequentially forming a gate insulating film made of SiN or SiO _2, a semiconductor active film made of Si, etc. and an ohmic film;
A fourth step of forming a source electrode made of a conductive film, a source wiring, and a drain electrode;
A first interlayer insulating film made of a photosensitive organic resin is formed, and a plurality of concave patterns are formed in the pixel region. At the same time, the first interlayer insulating film made of the photosensitive organic resin has a surface other than the concave pattern. A fifth step of forming a plurality of concave depressions in a flat region and forming a plurality of contact holes for electrical connection with the lower electrode;
A method of manufacturing a liquid crystal display device having a reflective display portion, which includes a sixth step of forming a reflective pixel electrode made of a reflective film in the pixel portion. A pair of substrates and a liquid crystal layer interposed between the pair of substrates are included. An insulating layer having an uneven surface on one of the pair of substrates and a part of the insulating layer are provided. A method of manufacturing a liquid crystal display device having a reflective display portion in which a pixel electrode that has irregularities on a cover surface and reflects light is formed, wherein a gate electrode and a gate wiring made of a conductive film are formed on the substrate A first step of forming;
A second step of forming an insulating film made of SiN or SiO ₂ and forming a plurality of convex patterns in the pixel region ;
A third step of sequentially forming a gate insulating film made of SiN or SiO _2, a semiconductor active film made of Si, etc. and an ohmic film;
A fourth step of forming a source electrode made of a conductive film, a source wiring, and a drain electrode;
A first interlayer insulating film made of a photosensitive organic resin is formed, and a plurality of concave patterns are formed in the pixel region. At the same time, the first interlayer insulating film made of the photosensitive organic resin has a surface other than the concave pattern. A fifth step of forming a plurality of concave depressions in a flat region and forming a plurality of contact holes for electrical connection with the lower electrode;
A sixth step of forming a second interlayer insulating film made of an organic resin so as to smooth the uneven shape formed in the pixel portion and forming a plurality of contact holes for electrical connection with the lower electrode When,
A method of manufacturing a liquid crystal display device having a reflective display portion, which includes a seventh step of forming a reflective pixel electrode made of a reflective film in the pixel portion. 8. A liquid crystal display device having a reflective display unit according to claim 6, wherein the plurality of concave depressions formed in a flat region on the surface other than the concave pattern of the first interlayer insulating film made of the organic resin has a stripe shape. The manufacturing method. A pair of substrates and a liquid crystal layer interposed between the pair of substrates are included. An insulating layer having an uneven surface on one of the pair of substrates and a part of the insulating layer are provided. A method of manufacturing a liquid crystal display device having a reflective display portion in which a pixel electrode that has irregularities on a cover surface and reflects light is formed, wherein a gate electrode and a gate wiring made of a conductive film are formed on the substrate A first step of forming;
A second step of forming an insulating film made of SiN or SiO ₂ and forming a plurality of convex patterns in the pixel region;
A third step of sequentially forming a gate insulating film made of SiN or SiO _2, a semiconductor active film made of Si, etc. and an ohmic film;
A fourth step of forming a source electrode made of a conductive film, a source wiring, and a drain electrode;
Forming a first interlayer insulating film made of an organic resin and forming a plurality of concave patterns in the pixel portion;
Further, a plurality of concave depressions are formed in a flat region on the surface other than the plurality of concave patterns of the first interlayer insulating film made of the organic resin using another mask pattern, and are electrically connected to the lower electrode. A sixth step of forming a plurality of contact holes for
A method of manufacturing a liquid crystal display device having a reflective display portion, which includes a seventh step of forming a reflective pixel electrode made of a reflective film in the pixel portion. A pair of substrates and a liquid crystal layer interposed between the pair of substrates are included. An insulating layer having an uneven surface on one of the pair of substrates and a part of the insulating layer are provided. A method of manufacturing a liquid crystal display device having a reflective display portion in which a pixel electrode that has irregularities on a cover surface and reflects light is formed, wherein a gate electrode and a gate wiring made of a conductive film are formed on the substrate A first step of forming;
A second step of forming an insulating film made of SiN or SiO ₂ and forming a plurality of convex patterns in the pixel region;
A third step of sequentially forming a gate insulating film made of SiN or SiO _2, a semiconductor active film made of Si, etc. and an ohmic film;
A fourth step of forming a source electrode made of a conductive film, a source wiring, and a drain electrode;
Forming a first interlayer insulating film made of an organic resin and forming a plurality of concave patterns in the pixel portion;
Further, a plurality of concave depressions are formed in a flat region on the surface other than the plurality of concave patterns of the first interlayer insulating film made of the organic resin using another mask pattern, and are electrically connected to the lower electrode. A sixth step of forming a plurality of contact holes for
A seventh step of forming a second interlayer insulating film made of an organic resin so as to smooth the uneven shape formed in the pixel portion and forming a plurality of contact holes for electrical connection with the lower electrode When,
A method of manufacturing a liquid crystal display device having a reflective display portion, which includes an eighth step of forming a reflective pixel electrode made of a reflective film in the pixel portion. In the fifth step, in order to form a plurality of concave patterns in the pixel portion of the first interlayer insulating film made of an organic resin, the portion from which the interlayer insulating film has been removed includes SiN or preparation of a liquid crystal display device having a reflective display portion of claim 9 or 10 wherein there are a plurality of regions in which a plurality of convex patterns formed in the pixel region of the insulating film made of SiO ₂ is present. The SiN or plurality of convex patterns formed in the pixel region of the SiO ₂ made of an insulating film is polygon close to a circle or circular, or of claim 9, 10 or 11, wherein a polygon close to the elliptical or oval A method for manufacturing a liquid crystal display device having a reflective display portion. Preparation of a liquid crystal display device having a reflective display portion of claim 9, 10 or 11, wherein a plurality of convex patterns are stripes to be formed in the pixel region of the insulating film made of the SiN or SiO _2. The reflection according to claim 9, 10, 11, 12, or 13, wherein the plurality of concave depressions formed in a flat region of the surface other than the plurality of concave patterns of the first interlayer insulating film made of an organic resin has a stripe shape. A method of manufacturing a liquid crystal display device having a mold display unit. A pair of substrates and a liquid crystal layer interposed between the pair of substrates, and an insulating layer having a concavo-convex shape on a surface of a pixel portion on one of the pair of substrates and the insulating layer A liquid crystal display device having a reflective display portion that covers a concavo-convex shape and is formed with a pixel electrode that reflects light, and a gate electrode and a gate wiring made of a conductive film formed on the one substrate,
A first convex pattern made of SiN or SiO ₂ formed on the one substrate;
A gate insulating film made of SiN or SiO ₂ formed so as to cover the gate electrode, the gate wiring, and the first convex pattern;
A semiconductor active film made of Si, formed to face the gate electrode through the gate insulating film;
An ohmic contact film formed on the semiconductor active film;
A source electrode, a source wiring, and a drain electrode made of a conductive film formed so as to be connected to the semiconductor active film through the ohmic contact film, and a plurality of concave patterns formed in the pixel portion so as to cover them When,
A first interlayer insulating film made of an organic resin having a plurality of contact holes for electrical connection with the drain electrode;
A reflective pixel electrode made of a reflective film formed on the first interlayer insulating film so as to cover the concavo-convex shape of the first convex pattern and the plurality of concave patterns. A liquid crystal display device having a reflection type display unit. A pair of substrates and a liquid crystal layer interposed between the pair of substrates, and an insulating layer having a concavo-convex shape on a surface of a pixel portion on one of the pair of substrates and the insulating layer A liquid crystal display device having a reflective display portion that covers a concavo-convex shape and is formed with a pixel electrode that reflects light, and a gate electrode and a gate wiring made of a conductive film formed on the one substrate,
A first convex pattern made of SiN or SiO ₂ formed on the one substrate;
A gate insulating film made of SiN or SiO ₂ formed so as to cover the gate electrode, the gate wiring, and the first convex pattern;
A semiconductor active film made of Si, formed to face the gate electrode through the gate insulating film;
An ohmic contact film formed on the semiconductor active film;
Said through an ohmic contact film semiconductor active film and the source electrode made of a conductive film formed to connect the source wiring, and the drain electrode, it is formed so as to cover them, concave-shaped plurality Te pixel portion smell Pattern of
A first interlayer insulating film made of an organic resin having a plurality of contact holes for electrical connection with the drain electrode;
A second interlayer insulating film made of an organic resin covering the first interlayer insulating film and having contact holes formed to be continuous with the plurality of contact holes for electrical connection with the drain electrode; ,
A reflective pixel electrode made of a reflective film formed on the second interlayer insulating film so as to cover the concavo-convex shape of the first convex pattern and the plurality of concave patterns ,
The liquid crystal display device having a reflective display section, wherein the second interlayer insulating film is formed so as to smooth the uneven shape . 17. The liquid crystal display having a reflective display unit according to claim 15, wherein a concave recess is formed in a flat region of a surface other than the plurality of concave patterns in the first interlayer insulating film. apparatus. 18. The device according to claim 15, wherein in the pixel portion, the portion where the first interlayer insulating film is removed has a plurality of regions where the plurality of first convex patterns exist. A liquid crystal display device having the reflective display unit according to claim 1.

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