JP4404747B2 - Reflective liquid crystal display device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a reflective liquid crystal display device having a reflector that reflects light transmitted through a liquid crystal layer from the outside to the outside again, and a method for manufacturing the same.

  Reflective liquid crystal display devices are mainly used for portable terminals because they can achieve lower power consumption, thinner thickness, and lighter weight than transmissive liquid crystal display devices. The reason for this is that a backlight is not required because light incident from the outside can be used as a display light source by reflecting it with a reflecting plate inside the apparatus.

  The basic structure of the present reflective liquid crystal display device is TN (twisted nematic), single polarizer, STN (super twisted nematic), GH (guest host), PDLC (polymer dispersion). A liquid crystal using a method, a cholesteric method, etc., a switching element for driving the liquid crystal, and a reflecting plate provided inside or outside the liquid crystal cell. These general reflective liquid crystal display devices employ an active matrix driving method that can achieve high definition and high image quality using thin film transistors (TFTs) or metal / insulating films / metal structure diodes (MIMs) as switching elements, This has a structure with a reflector.

  FIG. 36 is a cross-sectional view showing a conventional reflective liquid crystal display device of a single polarizing plate type. Hereinafter, description will be given based on this drawing.

  The counter substrate 1 is composed of a polarizing plate 2, a retardation plate 3, a glass substrate 4, a color filter 5, a transparent electrode 6, and the like. The lower substrate 7 includes a glass substrate 8, a thin film transistor 9 having an inverted stagger structure as a switching element formed on the glass substrate 8, a convex shape 10 made of an insulating film serving as a base of a concavo-convex structure, and an interlayer formed thereon It is composed of a polyimide film 11 which is an insulating film, a reflective electrode 13 which is connected to the source electrode 12 of the thin film transistor 9 and functions as a reflector and pixel electrode. A liquid crystal layer 14 is located between the opposing substrate 1 and the lower substrate 7.

  The light source uses reflected light 16. The reflected light 16 is that incident light 15 from the outside passes through the polarizing plate 2, the phase difference plate 3, the glass substrate 4, the color filter 5, the transparent electrode 6, and the liquid crystal layer 14 and is reflected by the reflective electrode 13. is there.

  The display performance of the reflective liquid crystal display device is required to display a bright and white display when the liquid crystal is in a transmissive state. In order to realize this display performance, it is necessary to efficiently emit incident light 15 from various directions forward. Therefore, by forming a concavo-convex structure in the polyimide film 11, the reflective electrode 13 positioned thereon can have a scattering function. Therefore, control of the concavo-convex structure of the reflective electrode 13 is important in determining the display performance of the reflective liquid crystal display device.

  37 and 38 are cross-sectional views showing a method of manufacturing a reflective electrode in a conventional reflective liquid crystal display device. Hereinafter, description will be given based on this drawing.

  In the thin film transistor manufacturing process, first, the gate electrode 21 is formed on the glass substrate 20 (FIG. 37 [a]). Subsequently, a gate insulating film 22, a semiconductor layer 23, and a doping layer 24 are formed (FIG. 37 [b]). Subsequently, the island 25 of the semiconductor layer 23 and the doping layer 24 is formed (FIG. 37 [c]), and the source electrode 26 and the drain electrode 27 are formed (FIG. 37 [d]). Then, it moves to the manufacturing process of a reflective electrode.

In the manufacturing process of the reflective electrode, first, the organic insulating film 28 having photosensitivity is formed (FIG. 37 [e]). Subsequently, the convex portion 29 is formed in the reflective electrode formation region by performing photolithography (FIG. 37 [f]), and the convex portion 29 is melted by heating to be converted into a smooth convex shape 30 (FIG. 38 [g] ]). Subsequently, a smoother uneven surface 32 is formed by covering the upper portion with the organic insulating film 31 (FIG. 38 [h]). Subsequently, a contact portion 33 for electrically connecting the reflective electrode to the source electrode of the thin film transistor is formed (FIG. 38 [i]), and then the reflective electrode 34 is formed (FIG. 38 [j]). The manufacturing method of this reflective electrode is disclosed, for example, in Japanese Patent Publication No. 61-6390 or Tohru koizumi and Tatsuo Uchida, Proceedings of the SID, Vol. 29, 157, 1988.
Japanese Patent Publication No. 61-6390 Proceedings of SID (Tohru koizumi and Tatsuo Uchida, Proceedings of the SID, Vol.29,157,1988)

  As described above, the concavo-convex structure of the insulating film located under the reflective electrode in the conventional reflective liquid crystal display device forms a convex portion serving as a base using an organic insulating film or an inorganic insulating film having photosensitive performance, Thereafter, the protrusion is covered with an organic insulating film or an inorganic insulating film.

  However, since metal wirings, electrodes, switching elements, and the like are formed under the protrusions, the metal wirings, electrodes, switching elements, etc. are exposed to the etching solution in the etching process when forming the protrusions. . As a result, the characteristics of the switching element are deteriorated due to the reaction between the etching solution and the base film, and the reliability of the switching element is reduced due to the remaining etching solution.

  Further, when an organic insulating film or an inorganic insulating film having no photosensitivity is used as the insulating film under the reflective electrode, a photoresist pattern is formed on the insulating film, and a convex pattern is formed by dry etching. In this case, since the base film is exposed to plasma during the etching process, the plasma damage causes deterioration of the switching element characteristics.

  On the other hand, the production of the conventional reflective liquid crystal display device requires a large number of processes as described above. For this reason, the unit cost of the reflective liquid crystal display device has increased due to an increase in manufacturing cost. The reason why the reflective liquid crystal display device requires a large number of manufacturing steps is that a high-performance switching element and a high-performance reflector are formed on the same insulating substrate in order to obtain a bright high-quality display. Furthermore, it is because it is necessary to use the method which can form the uneven structure on the surface of a reflecting plate in desired shape for manufacture of a high performance reflecting plate. Therefore, in the conventional reflection type liquid crystal display device, a large number of film forming steps, PR (photoresist) steps, etching steps and the like are required.

  On the other hand, the present condition is that the effective means of simplification of a manufacturing process is not taken. Again, the concavo-convex structure located under the reflective electrode is manufactured as follows. First, a photosensitive resin is applied and formed, and the photosensitive resin is patterned by an exposure process and a development process to form a convex pattern. However, the photosensitive resin film is completely removed from the region where the convex pattern is not formed. Thereafter, a heat treatment is applied to the convex pattern to convert it into a round convex shape, and in order to create a desired smooth irregular surface, an organic insulating layer is applied and formed so as to cover the convex pattern.

  That is, the insulating film under the reflective electrode is composed of two layers of a film having a convex shape and a film covered thereon. The insulating film functions as an interlayer insulating film that electrically insulates the reflective electrode from the switching element and the wiring. Thereafter, after forming a contact hole in this insulating layer, a metal thin film such as aluminum is deposited, and this metal thin film is patterned to obtain a reflective electrode reflecting the fine uneven shape of the insulating film.

  Thus, for the formation of the reflective electrode, 1) an insulating film forming step for forming a convex portion as a base, 2) a convex portion forming step, 2) an insulating film forming step on the convex pattern, and 3) a contact The hole forming step, 4) the high reflection efficiency metal thin film forming step, 5) the reflective electrode forming step, and the number of five steps are required.

  Accordingly, an object of the present invention is to realize a high luminance and high quality display performance by preventing deterioration of the characteristics of the switching element during the manufacturing process, and to realize a reduction in manufacturing cost by reducing the number of manufacturing processes. TYPE LIQUID CRYSTAL DISPLAY DEVICE AND ITS MANUFACTURING METHOD

The reflective liquid crystal display device of the present invention that solves the above problems includes a transparent first substrate, a transparent electrode provided on the first substrate, a second substrate, and the second substrate. A switching element provided; an insulating film provided on the switching element and having an irregular concavo-convex structure formed on a surface thereof; and the switching element provided in a shape reflecting the concavo-convex structure on the insulating film And a liquid crystal layer sandwiched between the transparent electrode side of the first substrate and the reflective electrode side of the second substrate. The insulating film covers the entire switching element except for a connection portion between the switching element and the reflective electrode, and the uneven structure formed on the surface is a smooth structure formed by linear protrusions. In addition, backlight light is transmitted by partially opening the reflective electrode . Thereby, the reflective liquid crystal display device of the present invention also serves as a transmission type.

  In the conventional reflective liquid crystal display device, since the convex shape is located on the metal wiring, electrode, switching element, etc., the base portion is exposed to the process atmosphere when forming the convex part, so the metal wiring, electrode, switching element As a result, the characteristics of the switching element deteriorated. On the other hand, since the insulating film in the present invention always covers the metal wiring, electrodes, switching elements, etc., the metal wiring, electrodes, switching elements, etc. are not exposed to the process atmosphere when forming the concavo-convex structure. These can be prevented from process damage. In addition, the insulating film in the present invention is composed of regions having different concavo-convex structures, that is, a thick region is a convex portion, and a thin region is a concave portion. Therefore, since no other film is required for the concavo-convex structure, the number of steps is reduced.

  In addition, since the reflective liquid crystal display device according to the present invention includes a reflective electrode having a continuous uneven structure having a smooth shape, bright display is possible. This is because the brightness of the reflective liquid crystal display device is determined by the tilt angle of the concavo-convex structure of the reflective electrode.

  Further, the insulating film on which the concavo-convex structure is formed may be a single layer film made of the same material. If the insulating film is formed in a single layer and in the same process, it is not necessary to form the concavo-convex structure portion and the interlayer insulating portion of the insulating film in separate steps. The process is simplified.

  In addition, the insulating film in which the uneven structure is formed may have light absorptivity. As a result, light incident from between adjacent reflective electrodes can be absorbed by the insulating film. Therefore, since the incident light which wraps around the back surface of the reflective electrode can be blocked, irradiation of the incident light to the switching element can be suppressed, so that good switching characteristics can be realized.

  Further, the concavo-convex structure may be one in which a plurality of protrusions are irregularly arranged. Thereby, since the interference of the reflected light from the reflective electrode can be suppressed, an uneven structure having good reflection performance can be formed. Further, the projections of the concavo-convex structure may be configured in an island shape or a linear planar shape. Thereby, bright reflection performance is obtained. That is, the reflective liquid crystal display device using these uneven structures can obtain bright display performance.

  Further, the concavo-convex structure may be a structure in which a plurality of depressions are irregularly arranged. Thereby, since interference of reflected light from the reflective electrode can be suppressed, an uneven structure having good reflector performance can be formed. Furthermore, you may comprise the hollow part of a concavo-convex structure by hole shape or a linear planar shape. Thereby, bright reflection performance is obtained. That is, the reflective liquid crystal display device using these uneven structures can obtain bright display performance.

  Further, the concavo-convex structure may be constituted by repeating irregular concavo-convex shapes of one pixel unit or two or more pixel units. As a result, interference of reflected light can be suppressed. Therefore, the reflective liquid crystal display device created using this reflective electrode has no wavelength dependency due to the light source, and there is no deterioration in color characteristics, and it is bright and high-quality display. It becomes performance.

  Further, the insulating film on which the concavo-convex structure is formed may be an organic resin or an inorganic resin having photosensitive performance. This makes it possible to form a desired concavo-convex pattern by directly exposing and developing the photosensitive resin, so that the steps of applying, forming, developing, and stripping the photoresist required to form the concavo-convex structure are performed. It becomes absolutely unnecessary. Accordingly, since the number of processes can be simplified, the cost of the reflective liquid crystal display device can be reduced.

  The reflective liquid crystal display device manufacturing method according to the present invention is a method of manufacturing the reflective liquid crystal display device according to the present invention. That is, in the concavo-convex structure, a predetermined pattern is formed by performing a photolithography process on the insulating film, and in this case, a pattern is formed leaving a predetermined film thickness, and a thin film area and a thick film area are planarized. By forming them irregularly, a concavo-convex structure is formed on the surface of the insulating film.

  As a result, the planar shape of the concavo-convex structure formed on the insulating film and its arrangement can be created in the insulating film reflecting the mask pattern, so that the planar shape can be accurately controlled, and the desired concavo-convex shape can be obtained. It can be formed with good reproducibility. Furthermore, if the insulating film is etched so as to leave a desired film thickness, the cross-sectional shape of the unevenness can be controlled with good reproducibility, so that an excellent uneven structure can be realized. In addition, since these manufacturing steps can be performed by only 1 PR step + 1 etching step, the process can be simplified. Further, since the metal wiring, electrode, switching element, and insulating film located under the uneven insulating film are not exposed to a process atmosphere (etching solution, etching gas, etc.), the metal wiring, insulating film, and switching element are not exposed. Thus, it is possible to realize a reflective liquid crystal display device having good element characteristics without causing damage.

  Furthermore, according to the present invention, the concavo-convex structure formed on the insulating film includes a step of forming the insulating film, a photolithography process for forming a concavo-convex resist pattern, and a predetermined film thickness under the insulating film. A smooth and continuous concavo-convex structure can be formed by a step of performing etching so as to leave a film, a step of removing a resist film remaining on the insulating film, and a step of melting the concavo-convex film by heat treatment. Good.

  According to such a manufacturing method, the concave / convex pattern can be processed without exposing the switching elements, wirings, electrodes, and the like located under the insulating film, so that the concave / convex patterns can be formed without damaging the switching elements. Can be formed. In addition, unlike the concavo-convex insulating film of the conventional reflective liquid crystal display device, the concavo-convex insulating film located under the reflective electrode does not require the base convex forming process and the film forming process thereon, so the same film is used. Since the uneven insulating film can be formed in the same process, the number of processes can be simplified.

  Furthermore, the concavo-convex structure formed in the insulating film includes a step of forming an organic insulating film or an inorganic insulating film having photosensitivity as the insulating film, an exposure step for forming a concavo-convex pattern, and the insulating film. A smooth and continuous concavo-convex structure may be manufactured by a developing process in which etching development is performed so as to leave a predetermined film thickness below, and a melt process in which the concavo-convex film is melted by heat treatment.

  This eliminates the need for applying, forming, developing, and stripping the resist required to form the concavo-convex structure, and allows the desired concavo-convex pattern to be formed by directly exposing and developing the photosensitive resin. As a result, the number of processes can be further simplified, and the cost of the reflective liquid crystal display device can be reduced.

  Further, an organic insulating film or an inorganic insulating film having photosensitivity may be used as an insulating film, and the concavo-convex structure and the contact portion may be simultaneously manufactured in the same developing process. According to such a manufacturing method, the concavo-convex structure and the contact hole can be formed by a simple method without using a resist process.

  At this time, by using a positive photosensitive material and increasing the exposure amount for forming the contact pattern rather than the exposure amount for forming the uneven pattern, it is possible to simultaneously form the uneven pattern and the contact pattern in the same development process. It may be. As a result, the contact formation step can be omitted, and the process can be simplified.

  According to the reflective liquid crystal display device and the method for manufacturing the same according to the present invention, the insulating film formed with the concavo-convex structure under the reflective electrode protects the switching element during the manufacturing process, and the regions having different film thicknesses are irregular. By being arranged, it is possible to prevent deterioration of the characteristics of the switching element during the manufacturing process, and it is possible to reduce the number of manufacturing processes because no other film is required for the uneven structure.

  FIG. 1 is a cross-sectional view showing a first embodiment of a reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  The reflective liquid crystal display device of this embodiment includes a glass substrate 53 as a transparent first substrate, a transparent electrode 55 provided on the glass substrate 53, a glass substrate 40 as a second substrate, and a glass substrate. The thin film transistor 44 serving as a switching element provided on the semiconductor layer 40, the insulating film 45 provided on the thin film transistor 44 and having a concavo-convex structure 45a formed on the surface thereof, and a shape reflecting the concavo-convex structure 45a on the insulating film 45 are provided. In addition, a reflective electrode 48 connected to the source electrode of the thin film transistor 44 and a liquid crystal layer 56 sandwiched between the transparent electrode 55 side of the glass substrate 53 and the reflective electrode 48 side of the glass substrate 40 are provided. The insulating film 48 protects the thin film transistor 44 after the formation of the thin film transistor 44, and the uneven structure 45a is formed by irregularly arranging regions having different film thicknesses.

  The thin film transistor 44 includes a gate electrode, a gate insulating film, a semiconductor film, and a source electrode formed by forming a metal layer 41, an insulating layer 42, a semiconductor layer 43, and the like, and subjecting these films to photolithography and etching. In addition, an inverted stagger structure composed of a drain electrode or the like is employed. An insulating layer 45 used for an organic insulating material or an inorganic insulating material is located on the thin film transistor 44. In the insulating film 45, regions having different film thicknesses are irregularly arranged to form a concavo-convex structure 45a having a desired shape. The concavo-convex structure 45a includes a thick convex portion 46 and a thin concave portion 47. A reflective electrode 48 is formed on the insulating film 45. The reflective electrode 48 is electrically connected to the source electrode of the thin film transistor 44 through a contact hole 49 formed in the insulating film 45, and also has a function as a pixel electrode.

  In addition, the uneven structure 45a formed in the insulating film 45 is reflected on the surface of the reflective electrode 48, and this uneven inclination angle determines the optical characteristics of the reflected light. Therefore, the inclination angle of the concavo-convex structure 45a is designed so as to obtain a desired reflection optical characteristic. In addition, the uneven structure 45a should just be comprised by 2 or more types of values from which any one of convex pitch, concave pitch, convex height, and concave depth differs.

  Next, the operation of the reflective liquid crystal display device of this embodiment will be described.

  The reflective liquid crystal display device operates as follows when in a white state. Incident light 50 incident from the outside of the glass substrate 53 passes through the polarizing plate 51, the retardation plate 52, the glass substrate 53, the color filter 54, the transparent electrode 55, and the liquid crystal layer 56, and the unevenness on the surface of the reflective electrode 48. The light is reflected according to the directivity reflecting the shape, passes through the liquid crystal layer 56, the transparent electrode 55, the color filter 54, the glass substrate 53, the phase difference plate 52, and the polarizing plate 51 and is returned to the outside as display light 58. On the other hand, the reflective liquid crystal display device operates as follows when in a black state. Incident light 50 incident from the outside of the glass substrate 53 passes through the polarizing plate 51, the retardation plate 52, the glass substrate 53, the color filter 54, the transparent electrode 55, and the liquid crystal layer 56, and is reflected by the reflective electrode 48. Since it is shielded by the polarizing plate 51, it is not emitted to the outside. Thereby, ON / OFF operation | movement of light is attained.

  FIG. 2 is a cross-sectional view showing a first embodiment of a manufacturing method of a reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  First, the thin film transistor 44 is formed on the glass substrate 40 (FIG. 2 [a]). Subsequently, an acrylic resin film 60 as an organic insulating film is applied and formed, a photoresist (not shown) is applied and exposed thereon to form an uneven pattern, and the uneven pattern is formed on the acrylic resin film 60 by etching. 61 is formed, and then the photoresist is peeled off (FIGS. 2B and 2C). Subsequently, a photoresist (not shown) is applied, exposed and developed again, the acrylic resin film 60 is etched, the photoresist is peeled off, and a contact hole 62 is formed in the acrylic resin film 60 (FIG. 2 [d]). . Finally, an aluminum film is formed, a photoresist is applied, exposed and developed, the aluminum film is etched, and the photoresist is peeled off to form the reflective electrode 63 (FIG. 2 [e]).

  In the formation of irregularities on the acrylic resin film 60 shown in FIGS. 2B and 2C, a convex portion 46 formed of a thick region and a concave portion 47 formed of a thin region are formed. By leaving the acrylic resin film 60 in the thin film region, the switching element 44 and the like are always covered with the acrylic resin film 60. At this time, by etching the acrylic resin film 60 under the resist pattern to a desired depth and leaving the thin acrylic resin film 60, the concavo-convex structure / interlayer insulating film can be formed by the same material and the same process. In addition, since the height 64 of the convex part 46 and the film thickness 65 of the recessed part 47 can be changed by controlling the etching amount, the uneven shape or the film thickness of the recessed part can be freely controlled.

  In this embodiment, acrylic resin is used for the insulating film, but a thickness that can satisfy the requirements of the uneven height required for the optical characteristics of the reflector and the film thickness required for the interlayer film is formed. Any insulating film can be used, and other organic resins such as polyimide resin may be used. Further, an inorganic insulating film such as a silicon nitride film or a silicon oxide film may be used.

  In consideration of the directivity of reflected light, the uneven structure at this time preferably has a height in the range of 0.2 to 4 μm and a pitch in the range of 1 to 30 μm. Furthermore, the convex portion or the concave portion is irregularly arranged on the plane, and the planar shape of the convex portion may be an island-shaped pattern or a linear pattern, and the planar shape of the concave portion may be a hole-shaped pattern or a groove-shaped pattern. Basically, it suffices if the pattern of these convex portions or concave portions is irregularly arranged, and this makes it possible to suppress interference of reflected light at the reflective electrode, so that bright and good wavelength-independent reflection is possible. The characteristics can be realized.

  3 and 4 are cross-sectional views showing a second embodiment of the manufacturing method of the reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  In this embodiment, the insulating film under the reflective electrode is composed of a concavo-convex shaped film and an interlayer film, which are formed in separate steps. First, the lower layer film 70 is formed by coating (FIG. 3B), and then the upper layer film 71 is formed by coating (FIG. 3C). Subsequently, by forming a concavo-convex pattern in the upper layer film 71 by patterning a photoresist, the upper layer film 71 is formed into the concavo-convex shape film 72 and the lower layer film 70 is formed into the interlayer film 73 (FIG. 4D). The other steps are the same as in the embodiment of FIG.

  The lower layer film 70 and the upper layer film 71 may be made of different materials. For example, an organic resin such as an acrylic resin, which is a material with good controllability of the concavo-convex shape, is used for the upper layer film 71, and a silicon nitride film that is a material excellent in electrical insulation performance, passivation property, process resistance, etc. Alternatively, an inorganic insulating film may be used for the lower layer film 70. In addition, the films used as the concavo-convex film 72 and the interlayer film 73 are not limited to the insulating materials described above as long as these required performances are satisfied, and various combinations of materials can be applied.

  In this embodiment, the case where a thin film transistor having an inverted stagger structure is applied as a switching element is described. However, the present invention is not limited to this, and a switching element such as a forward staggered structure thin film transistor or an MIM diode may be used. Moreover, although the glass substrate was used for the lower side substrate and the opposite side substrate, the present invention is not limited to this, and other substrates such as a plastic substrate, a ceramic substrate, a semiconductor substrate, etc. may be used, and these different substrates may be combined. Good.

  FIG. 5 is a cross-sectional view showing a third embodiment of the manufacturing method of the reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  In the present embodiment, a heat treatment is performed after the protrusions are formed to change the uneven shape, so that a smooth uneven shape is used for the uneven structure under the reflective electrode. The process up to the process of FIG. 5A is performed in the same process as the thin film transistor manufacturing process shown in FIG. Subsequently, an insulating film 74 having a concavo-convex structure is formed (FIG. 5B), and the insulating film 74 is melted by heat treatment to be changed to a smooth concavo-convex insulating film 74 ′ (FIG. 5C). ). By changing the baking temperature and baking time at this time, the melting state of the convex portion of the insulating film 74 changes, and therefore the finally formed uneven shape can be controlled by this melting condition. In this embodiment, the concavo-convex structure is made smooth and continuous by heat treatment. However, the present invention is not limited to this. For example, by exposing a material used for the concavo-convex structure to a solution having meltability or swelling property. The uneven surface can be converted into a smooth shape.

  Thereafter, the contact hole 62 is formed (FIG. 5 [d]), and the reflective electrode 63 is formed (FIG. 5 [e]), thereby completing the production of the reflective TFT substrate. As a result, the uneven shape formed on the surface of the reflective electrode 63 becomes smoother, so that the reflective optical characteristics are improved, and the reflective liquid crystal display device using this TFT substrate can realize a bright display. In this embodiment, in order to obtain a smooth uneven surface, a melting method by heat treatment is used. However, the present invention is not limited to this, and the same effect can be obtained by dissolving with a chemical as another method.

  In the meantime, in the embodiment shown in FIGS. 2 and 5, the insulating film located under the reflective electrode is formed in the same process and using the same material. That is, a single-layer film is formed as an insulating film under the reflective electrode, and this single-layer film is patterned by a photolithography process, and the insulating film is etched. A thin region is selectively formed and used for the concavo-convex structure. Therefore, since the concavo-convex structure can be formed with a single layer film, it is most suitable for shortening the manufacturing process, and a reflective liquid crystal display device can be provided at low cost.

  In each of the above embodiments, the concavo-convex structure is formed by selectively forming a thick region and a thin region of the insulating film on a plane by a photolithography process, but the present invention is not limited to this. As other methods, the film thickness of the printing resin by screen printing may be controlled, or the difference in film thickness may be generated by roughening the surface of the insulating film with a chemical solution to form a step.

  In the embodiment shown in FIGS. 2 and 5, the insulating film located under the reflector plate is formed of the same process and the same material. However, the present invention is not limited to this, and as shown in the embodiments of FIGS. 3 and 4, the base film and the upper convex film may be formed in different processes, or the uneven structure is formed using films of different materials. May be. Even if a reflective electrode is produced by using this for an uneven structure of an insulating film, a reflective electrode having desired optical characteristics can be provided. However, in this case, although there is a disadvantage that the number of steps is increased, there is an advantage that the thickness of the base film can be reliably controlled.

  FIG. 6 is a cross-sectional view showing a second embodiment of the reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  In this embodiment, the insulating film 45 formed under the reflective electrode 48 is formed so as to cover the thin film transistor 44, the wiring 80, the electrode 81, and the like. A reflective electrode 48 serving as a reflective plate and pixel electrode electrically connected to the thin film transistor 44 by a contact portion 49 has a structure in which an interlayer is separated through an insulating film 45. That is, the insulating film 45 has a function as a protective film. The insulating film 45 in this embodiment is used as a passivation film for the thin film transistor 44 by directly contacting the thin film transistor 44. A silicon nitride film (SiN) or silicon oxide film (SiO) conventionally used as a protective film for the thin film transistor 44 may be inserted between the insulating film 45 and the thin film transistor 44.

  FIG. 7 is a cross-sectional view showing a third embodiment of the reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  In the present embodiment, the insulating film 101 formed under the reflective electrode 48 may be an organic resin or an inorganic resin as long as it has insulating performance, and further has transparency, coloring property, light absorption property, and the like. You may do it. In particular, when the insulating film 101 has light absorptivity, the light 100 incident between the adjacent reflective electrodes 48 can be completely absorbed by the insulating film 101, so that light incident on the thin film transistor 44 can be prevented. As a result, light off-leakage of the thin film transistor 44 characteristic can be prevented, so that a reflective liquid crystal display device having good switching element characteristics can be realized.

  The insulating film 101 having light absorption at this time is not particularly limited to this position because a similar effect can be realized as long as the insulating film 101 is disposed so as to prevent light from being applied to the thin film transistor 44. . In addition, since the insulating film 101 also serves as an insulating film having a smooth concavo-convex structure formed under the reflective electrode 48, the process can be simplified. If the product names “Black Resist”, “CFPR”, “BK-748S”, “BK-430S”, etc., manufactured by Tokyo Ohka Kogyo Co., Ltd. are used as the material of the insulating film 101, the formation of a good light absorption layer, In addition, a good uneven structure can be formed. Similar effects can be obtained with other black resin materials. Further, the light absorbing layer may be a light reflecting film in addition to the light absorbing property, or may be a metal material, or an insulator or inorganic compound film that does not transmit light.

  FIG. 8 is a plan view of a mask pattern showing a fourth embodiment of the reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  As shown in each of the above embodiments, the cross-sectional shape of the concavo-convex structure of the insulating film located under the reflective electrode is obtained by selectively forming a thick region and a thin region in a planar manner in the insulating film formation region. Is formed. This uneven structure is reflected in the uneven structure on the surface of the reflective electrode. The uneven structure of the insulating film is formed using a pattern irregularly arranged on the mask. FIG. 8 shows a mask pattern corresponding to one pixel used for forming the unevenness. Reference numerals 110 and 112 are light transmission regions.

  In the present embodiment, the convex patterns are irregularly arranged, and the size of the convex patterns is about 2 to 20 μm for the outer shape and about 2 to 40 μm for the pitch. In FIG. 8A, island-shaped convex patterns 111 are irregularly arranged, and in FIG. 8B, linear convex patterns 113 are irregularly arranged. In the concavo-convex structure formed using either mask, it becomes possible to form a reflective electrode having good reflective optical characteristics. Therefore, a reflective liquid crystal display device manufactured using the same can obtain good display characteristics.

  In the present embodiment, island-shaped patterns having the same size or linear patterns having the same line width are used, but the present invention is not limited to this. For example, island-shaped patterns may be used with different sizes, and each pattern may be a polygon pattern (triangle, pentagon, hexagon, heptagon, etc.) other than a square, a circle, an ellipse, etc. Further, the same effect can be obtained even when patterns having various shapes are mixed. Further, the linear pattern may be a line pattern with various widths or a curved pattern, and these patterns may be non-uniform. Further, a mixture of island patterns and linear patterns may be used.

  FIG. 9 is a plan view of a mask pattern showing a fifth embodiment of the reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  In the mask pattern of this embodiment, the unevenness of the mask pattern in FIG. 8 is inverted. That is, the hole-shaped concave pattern 115 or the groove-shaped concave pattern 117 is irregularly arranged. Even when such a mask pattern was used, a high-intensity reflective electrode could be obtained. The size of the concave pattern of the mask pattern used at this time has an outer shape of about 2 to 20 μm and a pitch of about 2 to 40 μm. Note that. Reference numerals 114 and 116 denote light shielding regions.

  Also in the case of the present embodiment, the hole-shaped pattern having the same size or the groove-shaped pattern having the same width is used, but the present invention is not limited to this. For example, holes having different sizes may be used, and each pattern may be a polygonal pattern (triangle, pentagon, hexagon, heptagon, etc.), circle, ellipse, etc. Further, the same effect can be obtained even when patterns having various shapes are mixed. Further, the groove pattern may be a line pattern or a curve pattern having various widths, and these patterns may be non-uniform. Further, a mixture of a hole pattern and a groove pattern may be used.

  FIG. 10 is an explanatory view showing a sixth embodiment of the reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  The uneven pattern in the present embodiment may be irregular in a range of one or more pixels of the reflective liquid crystal display device, and may be irregular in a region of 3 pixels or 4 pixels such as RGB or RGGB. Further, an irregular uneven pattern may be formed in a region having a larger number of pixels, and this may be repeated to form unevenness in the reflective electrode region on the entire panel display unit. In this case, a bright reflector similar to the case where the entire surface of the reflector panel is formed with a complete irregular pattern can be obtained.

  10A shows an example in which the entire display area is formed with one irregular arrangement pattern, FIG. 10B shows an example in which the entire display area is formed by repeating the irregular arrangement pattern in units of one pixel, and FIG. ] Shows an example in which the entire display area is formed by repeating an irregular arrangement pattern of a unit of one pixel or more. Desirably, an irregular region is formed in units of one or more pixels, and the irregular region pattern is repeated to form irregularities in the entire reflective electrode region. In the present embodiment, an island pattern is shown, but the present invention is not limited to this. As shown in FIGS. 8 and 9, the same effect can be realized in any of a linear pattern, a hole pattern, a groove pattern, and the like.

  11 and 12 are cross-sectional views showing a fourth embodiment of the manufacturing method of the reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  This embodiment is different from the embodiment of FIG. 2 in that the insulating film used under the reflective electrode is made of a material having photosensitivity, and other than that is the same as the embodiment of FIG. FIG. 11 shows a case where a concavo-convex pattern is formed on the insulating film 133 using a photoresist (comparative example), and FIG. 12 shows a case of this embodiment. In the case of this embodiment, the upper layer unevenness 130 and the lower layer film 131 of the insulating film located under the reflective electrode are both composed of the photosensitive resin 132. In this case, the photosensitive resin 132 is applied and formed, and then the upper layer unevenness 130 and the lower layer film 131 are simultaneously formed in the exposure and development processes.

  In this embodiment, since the photosensitive resin is used, FIG. 11 [b1], [c1], and [d1] which are processes of the mask pattern 135 by the photoresist layer 134 are not required. That is, since the patterning can be performed by directly exposing and developing the photosensitive resin, the resist coating and peeling process can be simplified, so that the number of manufacturing processes shown in the comparative example of FIG. A reflective liquid crystal display device can be provided at low cost.

  In addition, you may use organic resin, such as an acrylic resin and a polyimide resin, or inorganic resin for the photosensitive resin in this embodiment. Further, as described above, the upper layer unevenness and the lower layer film of the insulating film under the reflective electrode may be made of a photosensitive resin of different materials, and further, only the upper layer unevenness or only the lower layer film is made of a photosensitive resin. Also good. Further, the lower substrate or the opposite substrate used in the present embodiment does not need to be a glass substrate, and a substrate made of another material may be used as described above. Moreover, the photosensitive resin in this embodiment does not need to be transparent, and may be black that can absorb light. In particular, a transparent photosensitive material may be used for the transflective type, and a black photosensitive material may be used for the reflective type (shown in the next seventh embodiment).

  FIG. 13 is a sectional view showing a seventh embodiment of the reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  FIG. 13A shows a reflective liquid crystal display device, and the insulating film 101a is made of a black photosensitive material. FIG. 13B shows a reflective liquid crystal display device (semi-transmissive liquid crystal display device) that also serves as a transmissive type, and the insulating film 101b is made of a transparent photosensitive material. By thinning the reflective electrode 48 'in FIG. 13B, the light of the backlight 140 can be transmitted. Note that the transflective liquid crystal display device is not limited to this configuration, and may have other configurations. For example, by partially opening a reflective electrode in a pixel, backlight light is generated in the region. 141 may be used.

  14 and 15 are cross-sectional views showing a fifth embodiment of the method for manufacturing a reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  In this embodiment, an inverted staggered thin film transistor is used as a switching element. The manufacturing process of the TFT substrate in this embodiment includes [a] formation of an electrode material, [b] formation of a gate electrode 150, [c] formation of a gate insulating film 151, a semiconductor layer 152, a doping layer 153, and a [d] electrode. Formation of material, [e] formation of island 154, [f] formation of source electrode 155 and drain electrode 156, [g] formation of insulating film 157, [h] formation of irregularities 158 on the upper layer of the insulating film, [i] ] Forming a contact hole 159, [j] forming a reflective electrode 160, and the like.

  Further, the step [h] includes (1) formation of a resist 163 on the insulating film 157, (2) formation of a concavo-convex pattern 164, (3) formation of the concavo-convex 158 on the upper layer portion of the insulating film 157, and (4) stripping of the resist. It consists of a process. At this time, the uneven height X and the film thickness Y of the lower layer can be controlled by the etching amount of the upper layer part of the insulating film 157 in the step (3). Therefore, the concavo-convex height X may be determined from the concavo-convex height necessary for the desired optical characteristics of the reflector, and the thickness Y of the lower layer film is determined by the coverage with respect to the underlying switching element, wiring, etc., insulation, etc. That's fine.

  In this embodiment, the case where an inverted staggered thin film transistor is applied as a switching element has been described. However, the present invention is not limited to this, and a switching element such as a forward staggered thin film transistor or an MIM diode may be used. Also, the inverted staggered thin film transistor is not limited to the structure shown in this embodiment, and may have a structure other than this. Moreover, although the glass substrate was used for the lower side substrate and the opposite side substrate, it is not limited to this, and other substrates such as a plastic substrate, a ceramic substrate, a semiconductor substrate, and the like may be used. Furthermore, in the present embodiment, the insulating film having the concavo-convex structure in the step (3) has a single film structure in the same step, but is not limited thereto.

  16 and 17 are cross-sectional views showing a sixth embodiment of the reflective liquid crystal display device manufacturing method according to the present invention. Hereinafter, description will be given based on this drawing.

  The manufacturing process other than the formation of the insulating film having the concavo-convex structure on the surface is the same as the manufacturing process of FIGS. That is, the concavo-convex insulating film of this embodiment is the same process as FIGS. 14A to 14F until the switching element is formed, and then (1) the insulating layer 161 for the interlayer film is formed, and (2) the concavo-convex The insulating layer 162 for formation is formed, (3) formation of the uneven pattern 164 with the resist 163, (4) formation of the uneven structure 165, and (5) resist removal.

  Thereby, the uneven | corrugated layer 166 and the lower layer film | membrane 167 of the insulating layer formed under a reflective electrode can be formed in another process. Therefore, using the acrylic resin that can easily control the concavo-convex shape for the concavo-convex layer in the upper layer part, and using the silicon nitride film with excellent passivation performance or electrical insulation for the lower part part, better optical characteristics, and A switching element substrate having good element characteristics can be provided. As a result, a reflective liquid crystal display device with high performance and high quality display can be realized.

  In addition, the uneven | corrugated layer and lower layer film | membrane used by this embodiment are not limited to this, You may use organic type insulation films, such as another polyimide, inorganic type insulation films, such as a silicon oxide film, and also The material of the upper layer and the lower layer may be the same.

  18 and 19 are cross-sectional views showing a seventh embodiment of the manufacturing method of the reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  In this embodiment, the point that the insulating film 157 used under the reflective electrode 160 is made of a material having photosensitivity is different from the embodiment of FIGS. 14 and 15, and the other points are FIGS. This is the same as the embodiment.

  According to the present embodiment, the patterning can be performed by directly exposing and developing the photosensitive resin, so that the resist coating and peeling process can be simplified, and the number of manufacturing steps shown in the embodiment of FIGS. As a result, the reflection type liquid crystal display device can be provided at low cost.

  20 and 21 are cross-sectional views illustrating an eighth embodiment of a method for manufacturing a reflective liquid crystal display device according to the present invention. Hereinafter, description will be given based on this drawing.

  The present embodiment is different from the embodiment of FIGS. 18 and 19 in that the contact hole forming step for the insulating film used under the reflective electrode is performed simultaneously with the unevenness forming step, and the other embodiments are the embodiment of FIGS. 18 and 19. Is the same as The manufacturing process of the TFT substrate in this embodiment includes [a] formation of an electrode material, [b] formation of a gate electrode, [c] formation of a gate insulating film, a semiconductor layer, and a doping layer, [d] formation of an electrode material, [E] An island is formed, and [f] a source electrode and a drain electrode are formed. Thereafter, [g] formation of the photosensitive insulating layer 170, [h] exposure to the photosensitive insulating layer (contact region 171 and uneven region 172), and [i] simultaneous contact and unevenness to the photosensitive insulating layer in the development step. Following the formation, the melt on the uneven surface by heat treatment, and the formation of the [j] reflective electrode 173.

  In the step [h] of the present embodiment, each pattern is exposed simultaneously to the contact formation region and the unevenness formation region in the same exposure step. Thereafter, in the development etching process, the unevenness forming portion is processed to have an etching depth of depth X, and the contact forming portion is processed to have an etching depth of depth Z.

  In this case, in the step [h], the exposure energy amount in the exposure process of the concavo-convex pattern portion 175 and the contact portion 174 is set so that the contact portion 174 is larger than the concavo-convex pattern portion 175, and further, the lower layer portion of the photosensitive insulating layer 170 May be adjusted so that the desired film thickness Y is obtained. As a method of adjusting the exposure amount, double exposure may be performed by using two types of masks for forming a concavo-convex pattern and a mask for forming a contact pattern so that each exposure amount is different. You may use the mask which adjusted the mask material so that the light transmittance of exposure with the uneven | corrugated pattern part and contact pattern part in a mask may differ. In this way, if the exposure energy of the exposure process is made different depending on the pattern portion, pattern formation having different etching amounts in the same substrate under the same development conditions can be realized. In this embodiment, the uneven surface is converted into a smooth shape by applying a heat treatment to the insulating film.

  According to the present embodiment, patterning can be performed by directly exposing and developing the photosensitive resin, and the unevenness forming step and the contact forming step can be realized by the same exposure and development etching step. The number of manufacturing steps shown in the nineteenth embodiment can be further shortened, and a reflective liquid crystal display device can be provided at low cost.

  In this embodiment, a photosensitive material is used for forming the uneven insulating layer. However, if a resist process is used, a similar structure can be obtained using a non-photosensitive material. However, although the number of steps is increased because a resist process is required, the number of steps can be shortened as compared with the manufacturing process of the conventional reflective liquid crystal display device.

  Example 1 A manufacturing process of a reflective liquid crystal display device used in this example is shown in FIGS. A forward staggered thin film transistor was adopted as the switching element.

  Manufacture performs the following processes on a glass substrate. [A] 50 nm of ITO is formed by sputtering. [B] Formation of source 200 and drain electrode 201. (1PR) [c] The doping layer 202 is 100 nm, the semiconductor layer 203 is 100 nm, and the gate insulating film 204 is formed by 400 nm plasma CVD. [D] A Cr layer 205 is formed to a thickness of 50 nm by sputtering. [E] Island 206 formation of gate electrode and TFT element part. (Second PR) [f] Formation of organic insulating film 207 (3 μm). [G] Formation of concavo-convex pattern 208 on the organic insulating film upper layer (3PR) [h] Formation of contact 209 (4PR) [i] 300 nm of aluminum is formed by sputtering. [J] Formation of the reflective pixel electrode plate 210. (5PR)

  In the step [c], a laminated film of a silicon oxide film and a silicon nitride film is used for the gate insulating film, an amorphous silicon film is used for the semiconductor layer, and an n-type amorphous silicon film is used for the doping layer. The CVD conditions were set as shown below. In the case of a silicon oxide film, silane and oxygen gas are used as the reaction gas, the gas flow rate ratio (silane / oxygen) is set to about 0.1 to 0.5, the film forming temperature is 200 to 300 ° C., the pressure is 133 Pa, and the plasma power. 200W. In the case of a silicon nitride film, silane and ammonia gas are used as the reaction gas, the gas flow ratio (silane / ammonia) is set to 0.1 to 0.8, the film forming temperature is 250 ° C., the pressure is 133 Pa, and the plasma power is 200 W. . In the case of an amorphous silicon film, silane and hydrogen gas are used as the reaction gas, the gas flow rate ratio (silane / hydrogen) is set to 0.25 to 2, the film forming temperature is 200 to 250 ° C., the pressure is 133 Pa, and the plasma power is 50 W. . In the case of an n-type amorphous silicon film, silane and phosphine are used as the reaction gas, the gas flow ratio (silane / phosphine) is set to 1 to 2, the film forming temperature is 200 to 250 ° C., the pressure is 133 Pa, and the plasma power is 50 W. .

  In the island formation of the TFT element portion in the above step [e], wet etching was adopted for the Cr layer, and dry etching was adopted for the silicon oxide film, silicon nitride film, and amorphous silicon layer. For the etching of the Cr layer, a mixed aqueous solution of perhydrochloric acid and ceric ammonium nitrate was used. For etching the silicon nitride film and the silicon oxide film, fluorine tetrachloride and oxygen gas were used as the etching gas, the reaction pressure was 0.665 to 39.9 Pa, and the plasma power was 100 to 300 W. The amorphous silicon layer was etched using chlorine and hydrogen gas at a reaction pressure of 0.665 to 39.9 Pa and a plasma power of 50 to 200 W. In the photolithography process, a normal resist process was used.

  In this embodiment, ITO is used for the source and drain electrodes and Cr metal is used for the gate electrode, but each electrode material is not limited to these. As an electrode material other than this, a single layer film such as Ti, W, Mo, Ta, Cu, Al, Ag, ITO, ZnO, SnO, or a laminated film of a combination of these electrodes may be adopted.

  In this embodiment, the unevenness formed under the reflective electrode is formed in the above [f] [g] process. That is, a resist film 2 μm is formed on the insulating film formed in the above step [f], an uneven resist pattern is formed by an exposure and development process, the insulating film is etched at a depth of 1 μm, and the resist is peeled off. An uneven structure can be formed in the upper layer portion of the insulating layer.

  A polyimide film (trade name “RN-812” manufactured by Nissan Chemical Industries, Ltd.) was used as the organic insulating film in the step [f]. In the case of the polyimide, the coating conditions were a spin rotation speed of 1200 rpm, a temporary baking temperature of 90 ° C., a temporary baking time of 10 minutes, a main baking temperature of 250 ° C., and a main baking time of 1 hour. On the other hand, in the case of the resist used for pattern formation, the spin rotation speed was 1000 rpm, the pre-baking temperature was 90 ° C., the pre-baking time was 5 minutes, and then the pattern was formed by exposure and development, followed by post-baking at 90 ° C. for 30 minutes. The dry etching conditions of the polyimide film performed using the resist pattern as a mask layer are as follows: fluorine tetrachloride and oxygen gas are used as the etching gas, and the gas flow ratio (fluorine tetrachloride / oxygen) is set to 0.5 to 1.5. The reaction pressure was 0.665 to 39.9 Pa, and the plasma power was 100 to 300 W. Note that a normal resist process was used for all photolithography processes.

  In this embodiment, the insulating layer formed in the same process is used for the concave-convex insulating layer located between the reflector and the TFT element. As another embodiment, the TFT formation of the above [e] is used. After completion, a first organic resin is formed (2 μm), a second organic resin is formed (1 μm), and a concavo-convex structure is formed on the second organic resin by performing a resist process and an etching process. A desired uneven insulating layer could be formed. The basic manufacturing process may be the same as the process described in the embodiment.

  In addition, although the same organic resin material is used for the first insulating film and the second insulating film, the uneven insulating layer can be similarly formed even if different materials are used. A combination of an inorganic resin and an organic resin such as an acrylic resin and a polyimide resin, a silicon nitride film and an acrylic resin, a silicon oxide film and a polyimide resin, or the reverse combination is used for the first insulating film and the second insulating film. But it was possible.

  In this embodiment, after that, an aluminum metal having high reflection efficiency and good consistency with the TFT process was formed, and this was patterned to form a pixel electrode / reflector. The aluminum at this time was wet-etched, and a mixed solution composed of phosphoric acid, acetic acid and nitric acid heated to 60 ° C. was used as the etching solution.

  In this embodiment, since the pattern forming process for forming the unevenness is performed in the state where the insulating layer is covered on the switching element in the unevenness forming process, the switching element is not directly exposed to the etching process. . For this reason, problems such as deterioration or instability in switching element characteristics due to process damage are not caused, so that a great achievement has been made in improving the performance of the reflective liquid crystal display.

  The maximum height of the unevenness was set to about 1 μm, and the planar shape of the unevenness was set to a random shape. Thereafter, the TFT substrate and the counter substrate having a transparent electrode made of ITO were overlapped so that the respective film surfaces were opposed to each other. The TFT substrate and the counter substrate were subjected to an alignment treatment, and the two substrates were bonded to each other by applying an epoxy adhesive to the peripheral portion of the panel through a spacer such as plastic particles. Thereafter, liquid crystal was injected to form a liquid crystal layer, thereby manufacturing a reflective liquid crystal display device.

  FIG. 24 is a cross-sectional view of the reflective liquid crystal display device obtained in this example. 24, reference numeral 212 denotes a counter substrate, 213 denotes an upper glass substrate, 214 denotes a color filter, 215 denotes ITO (indium tin oxide), 216 denotes incident light, 217 denotes reflected light, 218 denotes liquid crystal, and 219 reflects. A plate, 220 is an organic insulating film, and 221 is a glass substrate.

  The reflective pixel electrode of this reflective liquid crystal display device is uniform and has a reflective performance with good light scattering properties. Therefore, a monochrome reflective panel having a white display brighter than newspaper can be realized at low cost. In addition, when an RGB color filter was installed on the counter substrate side, a bright color reflective panel was realized at low cost.

  In addition, the height of the unevenness | corrugation of a present Example is not limited above. Since the height of the unevenness can be changed in a wide range, by using this uneven structure, it is possible to provide a reflective liquid crystal display device in which the directivity of the reflector performance is greatly changed.

  (Embodiment 2) FIGS. 25 and 26 show the manufacturing process of the reflective liquid crystal display device used in this embodiment. A thin film transistor having an inverted stagger structure is employed as a switching element in the reflective liquid crystal display device.

  Manufacture performs the following processes on the glass substrate 230. [A] Cr is formed to 50 nm by sputtering. [B] Formation of the gate electrode 231. (1PR) [c] The gate insulating film 232 is formed by 400 nm, and the semiconductor layer 233 and the doping layer 234 are formed by 100 nm plasma CVD. [D] Island formation 235 (2PR eyes) [e] Cr and ITO layers were each formed by sputtering to a thickness of 50 nm. [F] Formation of source electrode 236 and drain electrode 237. (3PR eyes) [g] Formation of organic insulating film 238 (3 μm). [H] Formation of concavo-convex pattern 239 on the organic insulating film upper layer (4PR) [i] Formation of contact 241 (5PR) [j] 300 nm of aluminum 242 is formed by sputtering. [K] Formation of reflective pixel electrode plate 243. (6PR eyes) [l] Gate line terminal extension (7PR eyes)

  In the present embodiment, the unevenness 240 formed at the lower part of the reflector is formed in the above [g] step. The formation method at this time was the same as in Example 1. In this embodiment, since the inverted stagger structure is adopted for the transistor structure, the number of processes is increased compared to the first embodiment.

  The aperture ratio of the reflective pixel electrode plate in this example was 86%. Thereafter, the TFT substrate and the counter substrate having a transparent electrode made of ITO were overlapped so that the respective film surfaces were opposed to each other. The TFT substrate and the counter substrate were subjected to an alignment treatment, and the two substrates were bonded to each other by applying an epoxy adhesive to the periphery of the panel through spacers such as plastic particles. Then, a reflective liquid crystal display device was manufactured by injecting GH type liquid crystal to form a liquid crystal layer.

  FIG. 27 is a sectional structural view of the reflective liquid crystal display device manufactured in this example. In FIG. 27, reference numeral 15 is incident light, 16 is reflected light, 239 is a resist uneven pattern, 241 is a contact, 243 is a reflector, 250 is a counter substrate, 251 is a glass substrate, 252 is a color filter, and 253 is a transparent electrode. Reference numeral 254 denotes a guest-host liquid crystal.

  Also in the case of the reflective liquid crystal display device in this example, process damage is not given to the switching element as in the case of Example 1, and thereby good element characteristics can be obtained and desired uneven reflection can be obtained. A plate structure could be obtained. As a result, the color reflective panel manufactured in this example had a bright high-quality display.

  (Example 3) In the present Example, the uneven surface located under a reflective electrode is comprised by smooth uneven shape. 28 and 29 are sectional structural views of the reflective liquid crystal display device manufactured in this example.

  This example is exactly the same as Example 1 or Example 2 except that a process for converting the unevenness under the reflective electrode into a smooth shape is added. The only difference is that in Example 1, the step [i] is performed, and in Example 2, the step of applying heat treatment is added after the formation of the concavo-convex pattern in the step [h]. Therefore, FIG. 28 is exactly the same as FIG.

  In this example, as the heat treatment step after forming the irregularities, a treatment was performed at 260 ° C. for 1 hour in an oven in a nitrogen atmosphere. Thereby, what the inclination angle of the unevenness | corrugation before heat processing was about 60 to 80 degree | times changed to about 10 to 40 degree | times after heat processing. That is, the obtained uneven shape was converted from a rectangular shape to a smooth uneven surface 261 having a sine curve shape. In the case of the reflective liquid crystal display device in this example, the average value of the uneven inclination angle on the uneven surface was set to be about 8 degrees. Further, the uneven inclination angle can be controlled by changing the baking temperature in the heat treatment step.

  In the present example, the height of the unevenness was set to 1 μm as in the case of the first and second examples. However, when the height of the unevenness is further increased, the obtained reflector can have a highly scattering optical property. In this case, when applied to a reflective liquid crystal display device having a particularly large screen size, the visual field dependency on the brightness of the panel display characteristics is small, so that an easy-to-see reflective liquid crystal display device can be obtained.

  Further, by reducing the height of the unevenness, the optical characteristics of the reflector can be obtained with strong directivity. In this case, brighter display characteristics can be realized by applying to a reflective liquid crystal display device for portable information equipment having a relatively small screen size. Thus, the uneven surface structure can be freely controlled according to the intended use or panel display area.

  In addition, the insulating layer in this embodiment functions as a protective film of the switching element by being positioned between the reflection plate positioned above and the switching element positioned below.

  (Example 4) In this example, the insulating layer located under the reflector is composed of an organic insulating film having photosensitive performance. 30 and 31 are sectional structural views of the reflective liquid crystal display device manufactured in this embodiment.

  The manufacturing process of the reflective liquid crystal display device in this example is the same as that in Example 1 or Example except that a photosensitive resin (photosensitive acrylic resin in this example) is used for the insulating layer in the lower part of the reflector. 2 can be exactly the same. The difference is that the photosensitive film 270 is used for the insulating layer formed in the step (f) in the first embodiment and in the step (g) in the second embodiment.

  By simply adding a photosensitive film process, the formation of irregularities becomes a photosensitive film forming process, a direct exposure process to the photosensitive film, an etching development process, and a melt process by heat treatment. This eliminates the need for resist coating, resist development, and resist stripping steps as compared with the irregularity forming steps performed in Examples 1, 2, and 3. Therefore, the process can be simplified.

  In this embodiment, a photosensitive acrylic resin is used as the photosensitive material, but the present invention is not limited to this. Similar effects could be realized with other photosensitive materials such as a photosensitive organic resin and a photosensitive inorganic film. As photosensitive materials, trade name “OFPR800” manufactured by Tokyo Ohka Kogyo Co., Ltd., trade name “LC100” manufactured by Shipley Co., Ltd., trade name “Optomer Series” manufactured by Nippon Synthetic Rubber Co., Ltd., Nissan Chemical Industries, Ltd. Even when the product name “photosensitive polyimide” was used, a similar uneven insulating layer was obtained.

  (Example 5) The manufacturing process of the reflective liquid crystal display device used for the present Example is shown in FIG.32 and FIG.33. A thin film transistor having an inverted stagger structure is employed as the switching element.

  Manufacture performs the following processes on the glass substrate 230. [A] Cr is formed to 50 nm by sputtering. [B] Formation of the gate electrode 231. (1PR) [c] The gate insulating film 232 is formed by 400 nm, the semiconductor layer 233 and the doping layer 234 are formed by 100 nm, respectively, by plasma CVD. [D] Island formation 235 (2PR eyes) [e] Cr and ITO layers were each formed by sputtering to a thickness of 50 nm. [F] Source electrode 237, drain electrode 236, formation of unevenness forming electrode 130. (3PR eyes) [g] Formation of photosensitive acrylic resin 270 (3 μm). [H] Irregular pattern and contact pattern exposure (4PR) on photosensitive acrylic resin [i] Simultaneous formation of irregularities 239 and contacts 241 by development etching process [j] 300 nm of aluminum 242 is formed by sputtering. [K] Formation of reflective pixel electrode plate 243. (5PR) [l] Gate line terminal (6PR)

  Thereafter, a reflective liquid crystal display device was manufactured by superimposing the counter substrate. The obtained reflective liquid crystal display device was able to realize bright high-quality color display.

  In this example, the same conditions as in the manufacturing process of Example 3 were adopted except for the simultaneous formation of the unevenness and the contact in the step (h). In this embodiment, the same development process was used to remove the insulating film having a film thickness of 3 μm so that the contact region was completely removed and the uneven region was left 2 μm of the lower layer film.

  Specifically, a single mask on which the contact pattern 280 and the uneven pattern 281 shown in FIG. 34 are drawn is used, and the light transmission amount of the contact pattern area at this time is larger than the light transmission amount of the uneven pattern. Thus, a mask in which the mask material 282 is controlled is used. As a result, the exposed photosensitive acrylic resin 283 has a difference in etching amount in the same development time as a result of different irradiation energy depending on the pattern. Therefore, an area where a desired film thickness is left and an area where etching is completely completed are obtained. It can be realized at the same time.

  In this embodiment, the light transmission amount is controlled so that the ratio of the transmission exposure amount is set to 3: 1 between the contact pattern portion and the uneven pattern portion. In the subsequent development process, by using the product name “NMD-3” manufactured by Tokyo Ohka Kogyo Co., Ltd., the development time is 90 seconds, the film is completely removed from the contact area, and the uneven area is 2 μm of the lower layer film. I was able to remain.

  In this example, the number of manufacturing steps on the TFT substrate side of the reflective liquid crystal display device is reduced by using photosensitivity for the insulating film, and further by performing unevenness and contact pattern formation at the same time, as compared with Examples 1-4. I was able to reduce it. Further, the PR number in the manufacturing process on the TFT substrate side at this time is 6, which can be reduced from 8 in the manufacturing process PR number on the TFT substrate side in the conventional reflection type liquid crystal display device. Can provide.

  In this embodiment, the exposure amount is controlled by controlling the transmission amount of the mask material of the mask for simultaneous formation of the concavo-convex pattern and the contact pattern. However, exposure is performed twice using the concavo-convex pattern mask and the contact pattern mask, respectively. It was also possible to do it. However, the exposure amount needs to be larger than the concavo-convex pattern exposure amount.

  Example 6 FIG. 35 is a cross-sectional view of a reflective liquid crystal display device used in an example of the present invention. 35, reference numeral 290 denotes a counter substrate, 291 denotes an uneven reflector, 292 denotes an uneven layer, 293 denotes a pixel electrode, 294 denotes a signal line, 295 denotes a liquid crystal layer, 296 denotes an insulating layer, and 297 denotes an MIM element.

  As the switching element, an MIM diode element composed of a metal, an insulating film, and a metal structure was adopted. Also in this case, the display performance was good as in the case where a thin film transistor was used as the switching element.

  According to the reflective liquid crystal display device and the method for manufacturing the same according to the present invention, the insulating film formed with the concavo-convex structure under the reflective electrode protects the switching element during the manufacturing process, and the regions having different film thicknesses are irregular. By being arranged, it is possible to prevent deterioration of the characteristics of the switching element during the manufacturing process, and it is possible to reduce the number of manufacturing processes because no other film is required for the uneven structure.

1 is a cross-sectional view showing a first embodiment of a reflective liquid crystal display device according to the present invention. It is sectional drawing which shows 1st embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 2 [a]-FIG. 2 [e]. It is sectional drawing which shows 2nd embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 3 [a]-FIG. 3 [c]. It is sectional drawing which shows 2nd embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 4 [d]-FIG. 4 [f]. It is sectional drawing which shows 3rd embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 5 [a]-FIG. 5 [e]. It is sectional drawing which shows 2nd embodiment of the reflection type liquid crystal display device which concerns on this invention. It is sectional drawing which shows 3rd embodiment of the reflection type liquid crystal display device which concerns on this invention. It is a top view of the mask pattern which shows 4th embodiment of the reflective liquid crystal display device which concerns on this invention, FIG. 8 [a] is a 1st example and FIG. 8 [b] is a 2nd example. It is a top view of the mask pattern which shows 5th embodiment of the reflective liquid crystal display device based on this invention, FIG. 9 [a] is a 1st example and FIG. 9 [b] is a 2nd example. It is explanatory drawing which shows 6th embodiment of the reflection type liquid crystal display device which concerns on this invention, FIG. 10 [a] is a 1st example, FIG. 10 [b] is a 2nd example, FIG. 10 [c] is a 3rd example. It is. It is sectional drawing which shows the comparative example in 4th embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 11 [a1]-FIG. 11 [f1]. It is sectional drawing which shows 4th embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 12 [a2]-FIG. 12 [c2]. It is sectional drawing which shows 7th embodiment of the reflective liquid crystal display device which concerns on this invention, FIG. 13 [a] is a 1st example and FIG. 13 [b] is a 2nd example. It is sectional drawing which shows 5th embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 14 [a]-FIG. 14 [g]. It is sectional drawing which shows 5th embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 15 [h]-FIG. 15 [k]. It is sectional drawing which shows 6th embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 16 [1]-FIG. 16 [3]. It is sectional drawing which shows 6th embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 17 [4]-FIG. 17 [6]. It is sectional drawing which shows 7th embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 18 [a]-FIG. 18 [g]. It is sectional drawing which shows 7th embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 19 [h]-FIG. 19 [k]. It is sectional drawing which shows 8th embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 20 [a]-FIG. 20 [h]. It is sectional drawing which shows 8th embodiment of the manufacturing method of the reflection type liquid crystal display device which concerns on this invention, and a process progresses in order of FIG. 21 [i]-FIG. 21 [j]. It is sectional drawing which shows the manufacturing method of the reflection type liquid crystal display device which concerns on Example 1 of this invention, and a process progresses in order of FIG. 22 [a]-FIG. 22 [f]. It is sectional drawing which shows the manufacturing method of the reflection type liquid crystal display device which concerns on Example 1 of this invention, and a process progresses in order of FIG.23 [g]-FIG.23 [j]. It is sectional drawing which shows the reflection type liquid crystal display device which concerns on Example 1 of this invention. It is sectional drawing which shows the manufacturing method of the reflection type liquid crystal display device which concerns on Example 2 of this invention, and a process progresses in order of FIG.25 [a]-FIG.25 [g]. It is sectional drawing which shows the manufacturing method of the reflection type liquid crystal display device which concerns on Example 2 of this invention, and a process advances in order of FIG.26 [h]-FIG.26 [l]. It is sectional drawing which shows the reflection type liquid crystal display device which concerns on Example 2 of this invention. It is sectional drawing which shows the manufacturing method of the reflection type liquid crystal display device which concerns on Example 3 of this invention, and a process progresses in order of FIG. 28 [a]-FIG. 28 [g]. It is sectional drawing which shows the manufacturing method of the reflection type liquid crystal display device which concerns on Example 3 of this invention, and a process progresses in order of FIG. 29 [h]-FIG. 29 [l]. It is sectional drawing which shows the manufacturing method of the reflection type liquid crystal display device which concerns on Example 4 of this invention, and a process progresses in order of FIG. 30 [a]-FIG. 30 [g]. It is sectional drawing which shows the manufacturing method of the reflection type liquid crystal display device which concerns on Example 4 of this invention, and a process progresses in order of FIG. 31 [h]-FIG. 31 [l]. It is sectional drawing which shows the manufacturing method of the reflection type liquid crystal display device which concerns on Example 5 of this invention, and a process progresses in order of FIG. 32 [a]-FIG. 32 [g]. It is sectional drawing which shows the manufacturing method of the reflection type liquid crystal display device which concerns on Example 5 of this invention, and a process progresses in order of FIG. 33 [h]-FIG. 33 [l]. It is sectional drawing which shows the manufacturing method of the reflection type liquid crystal display device which concerns on Example 5 of this invention. It is sectional drawing which shows the reflection type liquid crystal display device which concerns on Example 6 of this invention. It is sectional drawing which shows the conventional reflection type liquid crystal display device. It is sectional drawing which shows the manufacturing method of the conventional reflection type liquid crystal display device, and a process progresses in order of FIG. 37 [a]-FIG. 37 [f]. It is sectional drawing which shows the manufacturing method of the conventional reflection type liquid crystal display device, and a process progresses in order of FIG. 38 [g]-FIG. 38 [j].

Explanation of symbols

53 Glass substrate (first substrate)
55 Transparent electrode 40 Glass substrate (second substrate)
44 Thin film transistor (switching element)
45 Insulating film 45a Uneven structure 48 Reflective electrode 56 Liquid crystal layer

Claims (10)

A transparent first substrate, a transparent electrode provided on the first substrate, a second substrate, a switching element provided on the second substrate, and provided on the switching element An insulating film having an irregular concavo-convex structure formed on the surface; a reflective electrode provided on the insulating film in a shape reflecting the concavo-convex structure and connected to the switching element; and the first substrate In a reflective liquid crystal display device comprising a liquid crystal layer sandwiched between a transparent electrode side and the reflective electrode side of the second substrate,
The insulating film covers the entire switching element except for the connection part between the switching element and the reflective electrode, and the uneven structure formed on the surface is a smooth structure formed by linear protrusions, And the backlight is transmitted by partially opening the reflective electrode,
A reflection-type liquid crystal display device that also serves as a transmission type .   2. The reflective liquid crystal display device according to claim 1, wherein the concavo-convex structure of the insulating film is a smooth structure in which the surface integral is melted by heat treatment.   2. The reflective liquid crystal display device according to claim 1, wherein the concavo-convex structure of the insulating film is a smooth structure in which the surface integral is dissolved by a chemical.   The reflective liquid crystal display device according to claim 1, wherein the insulating film has light absorption.   5. The reflective liquid crystal display device according to claim 1, wherein the insulating layer is a single layer film made of the same material.   4. The reflective liquid crystal display device according to claim 1, wherein the insulating layer is a laminated film of an inorganic insulating film and an organic resin.   The reflective liquid crystal display device according to claim 1, wherein convex portions are irregularly arranged in the concavo-convex structure.   The reflective liquid crystal display device according to claim 1, wherein the concavo-convex structure is formed by repeating irregular concavo-convex shapes of one pixel unit or two or more pixel units.   The reflective liquid crystal display device according to claim 1, wherein the insulating film is made of an organic resin or an inorganic resin having photosensitive performance.   The reflective liquid crystal display device according to claim 1, wherein the concavo-convex structure has convex portions connected in a mesh pattern.

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