JP2009093145A - Display device and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device that allows a reduction in manufacturing costs and an improvement in yield, and a method of manufacturing the same. <P>SOLUTION: The method of manufacturing a liquid crystal display device includes: a TFT array substrate; an opposing substrate arranged to be opposed to the TFT array substrate; and a liquid crystal layer sandwiched between the TFT array substrate and the opposing substrate. The method includes the steps of: forming an organic planarization film 14 on the TFT array substrate; forming a reflective pixel electrode on the organic planarization film 14; forming a step at the organic planarization film 14 by decreasing film thickness of the film 14; and depositing an upper transparent conductive film 18 so as to be divided at the step of the organic planarization film 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a display device and a method for manufacturing the display device.

2. Description of the Related Art In recent years, liquid crystal display devices that use liquid crystals as display electro-optical elements have features such as low power consumption and thinness, and are actively commercialized as one of flat panel displays that replace CRTs.
The liquid crystal display device includes a passive (simple) matrix type liquid crystal display device and an active matrix type liquid crystal display device. Active matrix liquid crystal display devices include TFT-LCDs that use thin film transistors (hereinafter referred to as TFTs) as switching elements. A TFT-LCD has characteristics superior to those of a CRT or a simple matrix type liquid crystal display device in terms of portability and display quality. For this reason, TFT-LCDs are widely used in notebook personal computers and the like.

In a TFT-LCD, a liquid crystal layer is sandwiched between a TFT array substrate on which TFTs are formed in an array and a counter substrate.
The TFT-LCD includes a reflective TFT-LCD, a transmissive TFT-LCD, and a transflective TFT-LCD. The transflective TFT-LCD has both reflective and transmissive characteristics. The reflective TFT-LCD performs display by providing a reflective layer on the TFT array substrate and reflecting ambient light. In the transmissive TFT-LCD, a light transmitting layer is provided on the TFT array substrate and the counter substrate. The transmissive TFT-LCD performs display by transmitting light from a light source provided on the back surface or side surface.
The reflective TFT-LCD has good display characteristics outdoors. However, the reflective TFT-LCD has poor visibility because the ambient light is dark indoors. On the other hand, the transmissive TFT-LCD has good display characteristics indoors. However, the visibility of the transmissive TFT-LCD is lowered because the light from the light source is darker than the ambient light outdoors.

  In recent years, there has been an increasing demand for mobile display devices such as small displays for mobile phones and portable music players, and medium-sized displays such as portable video players, PDAs, and in-vehicle navigation. The transflective TFT-LCD has good display characteristics even in both indoor and outdoor environments. Therefore, with the increase in demand for these mobile display devices, the demand for transflective TFT-LCDs has increased.

  In the TFT-LCD, a signal line and a gate line are crossed and formed for each pixel on a glass substrate using a semiconductor technology. In the TFT-LCD, a TFT is formed at the intersection of the signal line and the gate line. Further, in the TFT-LCD, a reflective pixel electrode (reflective layer) or a transmissive pixel electrode (translucent layer) is formed for each pixel. In this way, a TFT array substrate is produced. Therefore, many processes are required for manufacturing the TFT array substrate. Therefore, there is a problem that the number of devices necessary for manufacturing the TFT array substrate increases and the manufacturing cost increases. In particular, in the transflective TFT-LCD, it is necessary to form both the reflective pixel electrode and the transmissive pixel electrode for each pixel on the TFT array substrate. Therefore, the number of processes is further increased as compared with the reflective TFT-LCD and the transmissive TFT-LCD. In the transflective TFT-LCD, the manufacturing cost increases. For this reason, reduction of the number of manufacturing processes is required.

  In a transmissive TFT-LCD, a transmissive pixel electrode is formed on a TFT array substrate, and a counter electrode is formed on a counter substrate. The transmissive pixel electrode and the counter electrode are formed of a transparent conductive film such as ITO (Indium Tin Oxide). Therefore, the work functions of the transmissive pixel electrode and the counter electrode can be made substantially the same. Thereby, when the liquid crystal is AC driven, the transmissive pixel electrode and the counter electrode can apply positive and negative voltages to the liquid crystal under substantially the same conditions. On the other hand, in a transflective TFT-LCD, a transmissive pixel electrode and a reflective pixel electrode are formed on a TFT array substrate. In a transflective TFT-LCD, a counter electrode is formed on a counter substrate. The transmissive pixel electrode and the counter electrode are formed of a transparent conductive film such as ITO. On the other hand, the reflective pixel electrode is formed of a metal film such as Al. Therefore, the work functions of the reflective pixel electrode and the counter electrode are different. As a result, display flickering may occur depending on the liquid crystal driving conditions. Also, due to the difference in work function between the reflective pixel electrode and the counter electrode, a so-called burn-in phenomenon occurs depending on the liquid crystal driving conditions. Here, burn-in is a phenomenon in which the previous image becomes an afterimage and the display quality is lowered.

  In order to avoid such flicker and burn-in, Patent Document 1 discloses a technique for forming a transparent conductive film made of the same material as the counter electrode on the reflective pixel electrode. In Patent Document 1, first, a metal film for forming a reflective pixel electrode is formed. Next, a transparent conductive film is formed on the metal film. Then, collective wet etching is performed with the same etching solution using the same mask pattern. As a result, a transparent conductive film having the same pattern shape as the reflective pixel electrode is formed on the reflective pixel electrode.

However, when the metal film and the transparent conductive film are collectively wet-etched by the method of Patent Document 1, the end of the transparent conductive film may extend laterally from the end of the metal film and remain in a bowl shape. . FIG. 9 is a cross-sectional view schematically showing a part of the manufacturing process of the TFT array substrate of the transflective liquid crystal display device according to Patent Document 1.
In the method of Patent Document 1, first, an interlayer insulating film 21 is formed on TFTs (not shown), scanning signal lines (not shown), and display signal lines (not shown). Next, a lower transparent conductive film 22 to be a transmissive pixel electrode is formed on the interlayer insulating film 21. Next, patterning is performed to form a transmissive pixel electrode (FIG. 9A). Next, a metal film 23 to be a reflective pixel electrode is formed so as to cover the lower transparent conductive film 22. Next, an upper transparent conductive film 24 is formed on the metal film 23 as a countermeasure against flicker and burn-in. Next, a resist 25 is formed in a desired shape on the upper transparent conductive film 24 (FIG. 9B). Then, the metal film 23 and the upper transparent conductive film 24 are wet etched together (FIG. 9C). Next, the resist 25 is removed (FIG. 9D).
Then, as shown in FIG. 9D, when the multilayer thin film pattern is formed by the method of Patent Document 1, the end of the upper transparent conductive film 24 in the upper layer is more lateral than the end of the lower metal film 23. Protruding bowl shape. In particular, when batch etching is performed using isotropic etching such as wet etching, the end of the upper transparent conductive film 24 tends to remain in a bowl shape.

  Then, as described above, when the end portion of the upper transparent conductive film 24 is formed in a hook shape, the hook portion is peeled off in a subsequent process. In particular, in the process of rubbing the substrate, such as rubbing, the heel portion is easily peeled off. And the peeled-off wrinkle part becomes a cause of foreign material generation. Further, the peeled ridge portion causes a short circuit between adjacent pixels and a short circuit with a pixel electrode (transmission pixel electrode, reflection pixel electrode). For this reason, the peeled-off wrinkle portion causes a display defect. Moreover, when the said ridge part is formed in a multilayer thin film pattern, when the said multilayer thin film pattern is coat | covered with a coating film, a step will arise with the said ridge part. And when a coating film is a protective insulating film, an insulation defect arises in the part of a step break. Further, when the coating film is a conductive film, a connection failure occurs at a stepped portion. In the future, as the pixel size becomes smaller, it becomes necessary to more effectively prevent the formation of wrinkles.

  Furthermore, Patent Document 1 includes a process of forming a lower transparent conductive film and performing patterning. Thereafter, a process of forming a metal film and an upper transparent conductive film and performing batch wet etching is provided. Therefore, there are many manufacturing processes, resulting in high costs. In addition, due to the large number of manufacturing processes, the chance of occurrence of defects due to foreign matters increases and the yield decreases.

  Therefore, Patent Document 2 describes a technique for manufacturing a transflective TFT-LCD by reducing the number of manufacturing processes. Conventionally, a TFT array substrate has been formed by six photolithography processes. Patent Document 2 discloses a method of forming a TFT array substrate by five photolithography processes. Specifically, in Patent Document 2, a photomask (photosensitive resin pattern) is formed using a halftone exposure technique. Then, a reflective pixel electrode and a transmissive pixel electrode are formed using one photomask. This reduces the manufacturing process.

Specifically, in Patent Document 2, first, a gate electrode / wiring, an insulating film, a semiconductor layer, a source / drain electrode / wiring, an organic planarization layer, and a contact hole formed between these layers are formed on a substrate. . Thereafter, a transparent conductive film to be a transmissive pixel electrode is formed. Then, a metal film is formed on the transparent conductive film. Thereafter, a photomask is formed using a halftone exposure technique. At this time, the thickness of the photomask in the reflective portion where the reflective pixel electrode is formed is thicker than that in the transmissive portion. Here, the transmissive part is a part other than the reflective part in the pixel region. Next, the metal film is etched to expose the transparent conductive film other than the region protected by the photomask. Next, ashing is performed to reduce the thickness of the photomask. Thereby, the metal film of the transmission part is exposed. Here, the ashing process is an ashing process that oxidizes and decomposes a resist with a dry etcher or the like, that is, an oxygen plasma process. At this time, the photomask with a reduced film remains in the reflecting portion. Next, the transparent conductive film other than the region protected by the photomask and the metal film of the transmission part is etched. Next, the transmissive pixel electrode is formed by etching the metal film in the transmissive portion. Further, the photomask remaining on the reflective portion is removed using a resist stripping solution to form a reflective pixel electrode.
JP 2005-275323 A JP 2005-215277 A

  However, in the manufacturing method of the TFT array substrate of Patent Document 2, the transparent conductive film is exposed when the ashing process is performed. When the ashing process is performed with the transparent conductive film surface exposed, abnormal discharge occurs. This damages not only the transparent conductive film but also the concavo-convex layer, insulating layer, and further lower wiring layer formed thereunder. This causes display failure due to dielectric breakdown or pattern disconnection.

  Therefore, as a method for avoiding the above-described problems caused by the ashing process, a method of performing wet etching after the photomask is formed and then performing the ashing process will be described with reference to the manufacturing process sectional view of FIG.

  First, a Mo film is formed to a thickness of 250 nm on the glass substrate 31 using a sputtering apparatus. Next, the resist is patterned using a photoengraving apparatus. Next, a wet etching process is performed to remove the Mo film not protected by the resist. Next, a resist stripping process is performed to remove the resist. Thereby, the gate wiring 32 is formed (FIG. 10A; gate forming step).

  Next, an insulating film (SiN: film thickness 400 nm) 33 and a semiconductor film (a-Si (i): film thickness 130 nm, a-Si (n): film thickness 50 nm) are formed using a CVD apparatus. Next, the resist is patterned using a photoengraving apparatus. Next, dry etching is performed to remove the semiconductor film that is not protected by the resist. Next, a resist stripping process is performed to remove the resist. Thereby, the semiconductor layer 34 is formed (FIG. 10B; semiconductor layer forming step).

  Next, a Mo film is formed to a thickness of 300 nm using a sputtering apparatus. Next, the resist is patterned using a photoengraving apparatus. Next, a wet etching process is performed to remove the Mo film not protected by the resist. Next, dry etching is performed to remove the semiconductor film (a-Si (n)) that is not protected by the resist. Next, a resist stripping process is performed to remove the resist. Thereby, the source / drain wiring 35 is formed (FIG. 10C; source / drain and channel formation step).

  Next, an insulating film (SiN: film thickness 100 nm) 36 is formed using a CVD apparatus (FIG. 10C). Next, a photosensitive organic resin film is formed by coating. Next, an organic flattening film 37 having a concavo-convex shape is formed by a photolithography apparatus using a photomask for forming a concavo-convex pattern. Here, the uneven shape is formed in the reflection portion. Next, dry etching is performed to remove the insulating film in the contact hole opening (FIG. 10D; organic planarization film forming step).

Next, using a sputtering apparatus, a lower transparent conductive film (ITO (Indium Tin Oxide) film: film thickness 80 nm) 38, a metal film (Mo: film thickness 50 nm, AlCu: film thickness 300 nm) 39, and an upper transparent conductive film A film (ITO: film thickness 5 nm) 40 is sequentially formed (FIG. 10E). The lower transparent conductive film 38 constitutes a transmissive pixel electrode. Further, the metal film 39 constitutes a reflective pixel electrode.
Next, the resist 41 is patterned using a halftone exposure technique. Here, the thickness of the portion corresponding to the reflective portion of the resist 41 is thicker than the thickness of the portion corresponding to the transmissive portion. Further, the thickness of the resist 41 where the resist 41 is left in the region other than the reflection portion and the region other than the transmission portion is equal to or greater than the thickness in the reflection portion. Next, a wet etching process is performed. Thus, the upper transparent conductive film 40, the metal film 39, and the lower transparent conductive film 38 that are not protected by the resist 41 are removed (FIG. 10F).
Next, an ashing process is performed to reduce the film thickness of the resist 41. Thereby, the resist 41 formed in the transmission part is removed. At this time, the resist 41 with a reduced film remains in the reflecting portion. In addition, the resist 41 with the reduced film remains in the region where the resist 41 having the same thickness as or more than the reflective portion is formed. At the same time, in this step, a part of the organic planarization film 37 is removed in the film thickness direction. Therefore, for example, the film thickness of the organic planarization film 37 on the upper layer of the TFT is reduced (FIG. 10G). Next, a wet etching process is performed. Thereby, the upper transparent conductive film 40 and the metal film 39 laminated on the transmission part are removed. Thereby, a transmissive pixel electrode is formed. Next, a resist stripping process is performed to remove the resist 41. Thereby, a reflective pixel electrode is formed (FIG. 10H). As a result, the TFT array substrate is formed.

  However, also in the method described above, the upper transparent conductive film is etched together with the metal film in the wet etching process shown in FIG. Therefore, in the reflective pixel electrode, the end portion of the upper transparent conductive film extends laterally from the end portion of the metal film and remains in a bowl shape.

  Moreover, in the manufacturing method of the TFT array substrate in the above-described method, the lower transparent conductive film, the metal film, and the upper transparent conductive film are successively laminated. Then, in the wet etching process after the ashing process (FIG. 10H), the upper transparent conductive film and the metal film are etched. At this time, the lower transparent conductive film must be selectively etched so as not to be etched. Therefore, there is a problem that the degree of process freedom is low.

  The present invention has been made to solve such problems, and it is an object of the present invention to provide a display device and a display device manufacturing method in which the manufacturing cost is reduced and the yield is improved.

  The method for manufacturing a liquid crystal display device according to the present invention includes a first substrate, a second substrate disposed opposite to the first substrate, and between the first substrate and the second substrate. A display material sandwiched between the substrate, a step of forming a base film on the first substrate, a step of forming a reflective pixel electrode on the base film, A step of forming a step in the base film, and a step of forming a transparent conductive film so as to be divided at the step of the base film after the step of forming the reflective pixel electrode.

  According to the present invention, the manufacturing cost is reduced and the yield is improved.

Hereinafter, embodiments to which the present invention can be applied will be described. Note that the present invention is not limited to the following embodiments. In the following embodiments, a liquid crystal display device will be described as an example of the display device.
[Embodiment 1]

  First, the configuration of the liquid crystal display device 400 according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a partial cross-sectional view showing a liquid crystal display panel portion of a liquid crystal display device 400 according to Embodiment 1 of the present invention. FIG. 2 is a plan view showing a configuration of a pixel of the TFT array substrate 100 according to the first embodiment of the present invention.

  As shown in FIG. 1, the liquid crystal display device 400 according to the first embodiment includes a TFT array substrate 100 (first substrate) and a counter substrate 200 (second substrate) disposed to face the TFT array substrate 100. ), And a liquid crystal layer 300 (display material) sandwiched between the TFT array substrate 100 and the counter substrate 200. 1, illustration of a liquid crystal layer 300 sandwiched between the TFT array substrate 100 and the counter substrate 200, a sealing material and a spacer for keeping the distance between the TFT array substrate 100 and the counter substrate 200 constant is omitted. To do.

  A TFT (Thin Film Transistor) 1 is formed in an array on the TFT array substrate 100. Specifically, in the TFT array substrate 100, the gate wiring 2 and the source / drain wiring 3 are formed so as to intersect each other on a transparent insulating substrate (hereinafter referred to as a glass substrate) 10 for each pixel (see FIG. (See FIG. 2). A TFT 1 is formed at the intersection of the gate line 2 and the source / drain line 3. Further, the TFT array substrate 100 includes a transmissive portion 5 having a transmissive pixel electrode 4, a reflective portion 7 having a reflective pixel electrode 6, a storage capacitor wiring 8, a contact hole 9, and the like on a glass substrate 10 for each pixel. It is formed (see FIG. 2). A pixel region is formed by the transmissive portion 5 and the reflective portion 7.

  The gate wiring 2 constitutes a TFT 1 serving as a switching element as a gate electrode. The storage capacitor line 8 is arranged in parallel with the gate line 2 and is near the center of the pixel region. The storage capacitor line 8 constitutes a storage capacitor for holding a voltage applied to the transmissive pixel electrode 4 and the reflective pixel electrode 6 for a predetermined time. The TFT array substrate 100 is provided with a driver IC to which various signals from the outside are supplied. And the edge part of the gate wiring 2 is electrically connected with the pad provided in driver IC as a gate terminal. As a result, an external image scanning signal is input to the gate wiring 2. The gate wiring 2 transmits an image scanning signal to the TFT 1.

  The insulating film 11 made of a transparent inorganic insulating material is formed so as to cover the gate wiring 2 and the storage capacitor wiring 8. The semiconductor layer 12 is formed on the gate wiring 2 via the insulating film 11 and constitutes the TFT 1. Further, a part of the semiconductor layer 12 formed on the gate wiring 2 is removed to constitute a TFT channel portion.

  The source / drain wiring 3 constitutes the TFT 1 as a source electrode. Further, the end of the source / drain wiring 3 is electrically connected as a source terminal to a pad provided in the driver IC. As a result, an external image signal is input to the source / drain wiring 3. The source / drain wiring 3 transmits an image signal to the TFT 1. A region surrounded by the adjacent gate wiring 2 and source / drain wiring 3 is a pixel region, and pixels are arranged in a matrix on the TFT array substrate 100.

  Further, the source / drain wiring 3 constitutes a TFT 1 as a drain electrode. Further, at least a part of the source / drain wiring 3 overlaps with the lower storage capacitor wiring 8 through the insulating film 11. As a result, charges are stored between the storage capacitor wiring 8 and the source / drain wiring 3, and a storage capacitor can be formed.

  The insulating film 13 is made of a transparent inorganic insulating material and is formed so as to cover the TFT 1, the gate wiring 2, and the source / drain wiring 3. The organic planarizing film 14 (underlying film) is made of a transparent organic resin material and is formed so as to cover the insulating film 13.

  In addition, a plurality of concavo-convex shapes 14 </ b> A for scattering reflected light are formed in part of the organic planarization film 14. A concave / convex shape 14A is formed in the region from the vicinity of the gate wiring 2 to the storage capacitor wiring 8 in each pixel region except the TFT 1 (see FIG. 2). Thereby, irregularities that determine the reflection characteristics are formed on the surface of the organic planarizing film 14.

  Then, a metal film 16 that is a reflective conductive film is formed on the concavo-convex shape 14 </ b> A of the organic planarization film 14. That is, the metal film 16 is provided in substantially the same region as the concavo-convex shape 14A, and is formed in substantially half of each pixel region except for the TFT1. The region where the metal film 16 is formed becomes the reflecting portion 7. Thereby, the light incident from the viewing side is reflected by the metal film 16 and is emitted to the viewing side.

  The lower transparent conductive film 15 constituting the transmissive pixel electrode 4 is provided over substantially the entire pixel region except for the TFT 1. A metal film 16 is disposed on the lower transparent conductive film 15. In other words, the lower transparent conductive film 15 is formed on the organic planarizing film 14, and the metal film 16 is formed on the lower transparent conductive film 15. In each pixel region, a region where the metal film 16 is not formed on the lower transparent conductive film 15 is a transmission portion 5, and a region where the metal film 16 is formed on the lower transparent conductive film 15 is a reflection. It becomes part 7. Specifically, a part of the lower transparent conductive film 15 is formed so as to protrude from the region where the metal film 16 is disposed. The portion of the lower transparent conductive film 15 that protrudes from the region where the metal film 16 is disposed serves as the transmission portion 5. The lower transparent conductive film 15 is made of a transparent conductive material. The transmissive pixel electrode 4 formed by the lower transparent conductive film 15 gives a signal potential to the liquid crystal layer 300.

  A contact hole 9 is formed on the source / drain wiring 3. The contact hole 9 is formed so as to penetrate the insulating film 13 and the organic planarizing film 14. The transmissive pixel electrode 4 is connected to the underlying source / drain wiring 3 through a contact hole 9.

  As shown in FIG. 1, the counter substrate 200 has a glass substrate 200A, a color filter layer 200B, and a counter electrode 200C. The color filter layer 200B includes, for example, a black matrix (BM) and a colored layer of red (R) green (G) blue (B). The color filter layer 200B is formed in the pixel region on the lower surface of the glass substrate 200A made of glass or the like, and performs color display. The counter electrode 200 </ b> C is disposed on the liquid crystal layer 300 side of the counter substrate 200, and provides a common potential for supplying a signal potential to the liquid crystal layer 300. In addition, the TFT array substrate 100 and the counter substrate 200 are bonded to each other with a sealant, and the liquid crystal layer 300 is inserted between them to be sealed.

  In addition, a liquid crystal alignment film (not shown) for aligning liquid crystals is applied and formed on the surfaces of the TFT array substrate 100 and the counter substrate 200. As the liquid crystal alignment film, a rubbing method that is currently widely applied can be used. The transflective liquid crystal display panel according to Embodiment 1 is configured as described above.

  As a method for forming the liquid crystal alignment film, a photo-alignment method, an inorganic alignment film (vertical alignment method), an oblique deposition method, an ion beam alignment method, a nanoimprint method, or the like may be applied instead of the rubbing method. According to these methods, it is possible in principle to reduce the number of misalignment regions in stepped portions and the like as compared with the rubbing method. As a result, a wide effective pixel area can be secured. In addition, it is possible to prevent a decrease in yield due to the generation of foreign matter, which is a drawback of the rubbing method. Furthermore, damage to the element due to static electricity can be reduced. Moreover, since the cleaning process after rubbing for removing foreign substances can be reduced, there is a merit that productivity is improved.

  In the liquid crystal display device 400 according to the first embodiment, in order to drive the transmissive pixel electrode 4 composed of the lower transparent conductive film 15, a TFT 1 serving as a switching element is disposed in each pixel. A transmissive pixel electrode 4 is electrically connected to the source / drain wiring 3. The TFT 1 is connected to the gate wiring 2. The ON / OFF of the TFT 1 is controlled by a signal input from the gate wiring 2. The TFT 1 is connected to the source / drain wiring 3. Then, a display voltage is applied to the transmissive pixel electrode 4 from the source / drain wiring 3 connected to the TFT 1.

  Thereby, an electric field corresponding to the display voltage is generated between the transmissive pixel electrode 4 and the counter electrode 200C. The liquid crystal is driven by the electric field generated between the substrates. That is, the alignment direction of the liquid crystal between the substrates changes, and the polarization state of light passing through the liquid crystal layer 300 changes. In addition, the voltage (drive voltage) actually applied to the liquid crystal can be changed by arbitrarily controlling the display voltage applied to the source / drain wiring 3. Since the voltage applied to the liquid crystal can be controlled by the source / drain wiring 3, the intermediate transmittance of the liquid crystal can be freely set in the liquid crystal driving state.

  Further, a polarizing plate (not shown), a retardation plate (not shown), and the like are provided on the outer surfaces of the TFT array substrate 100 and the counter substrate 200. Further, a backlight unit (not shown) or the like is disposed on the non-viewing side of the liquid crystal display panel. The polarizing plate absorbs light that vibrates in one direction and passes only light that vibrates in the other direction, thereby producing linearly polarized light. The phase difference plate mainly causes a specific phase difference such as λ / 2 or λ / 4. These are called λ / 2 plate and λ / 4 plate, respectively. Such a retardation plate is used for optical compensation, and is also used for widening the viewing angle.

  In the transmissive portion 5, light incident from the backlight passes through the polarizing plate on the TFT array substrate 100 side to become linearly polarized light, and passes through the phase difference plate to generate a specific phase difference. Further, the light passes through the glass substrate 10 and enters the liquid crystal layer 300. By passing through the liquid crystal layer 300, the polarization state of light changes. Thereafter, the light passes through the glass substrate 200A, the phase difference plate, and the polarizing plate, becomes linearly polarized light, and is emitted to the viewing side.

  In the reflecting portion 7, light incident from the viewing side passes through the polarizing plate on the counter substrate 200 side to become linearly polarized light, and passes through the retardation plate to generate a specific phase difference. Further, the light passes through the glass substrate 200 </ b> A and enters the liquid crystal layer 300. By passing through the liquid crystal layer 300, the polarization state of light changes. Then, the light incident on the liquid crystal layer 300 is reflected by the metal film 16. As a result, the light passes through the liquid crystal layer 300 again, and the polarization state of the light changes. Thereafter, the light passes through the glass substrate 200A, the phase difference plate, and the polarizing plate, becomes linearly polarized light, and is emitted to the viewing side.

  Further, the amount of light passing through the polarizing plate on the counter substrate 200 side varies depending on the polarization state of the light passing through the liquid crystal layer 300. That is, the amount of light that passes through the polarizing plate on the viewing side among the transmitted light that is transmitted from the backlight unit through the liquid crystal display panel and the reflected light that is incident from the outside changes. The alignment direction of the liquid crystal changes depending on the applied display voltage. Therefore, the amount of light passing through the viewing-side polarizing plate can be changed by controlling the display voltage. That is, a desired image can be displayed by changing the display voltage for each pixel.

  Next, a method for manufacturing the liquid crystal display device 400 according to the first embodiment of the present invention will be described. Here, among the methods for manufacturing the liquid crystal display device 400, the method for manufacturing the TFT array substrate 100 will be described with reference to FIG. FIG. 3 is a process cross-sectional view illustrating the manufacturing process of the TFT array substrate 100 according to the first embodiment. 3 is a cross-sectional view showing a cross section of the gate terminal portion and a cross section of the source terminal portion in addition to the III-III cross section of FIG.

  First, a Mo film is formed on the glass substrate 10 with a thickness of 250 nm using a sputtering apparatus. Next, the resist is patterned using a photoengraving apparatus. That is, a resist pattern is formed by photolithography. Next, a wet etching process is performed to remove the Mo film not protected by the resist. Next, a resist stripping process is performed to remove the resist. Thereby, the gate line 2 and the storage capacitor line 8 are formed (FIG. 3A; gate formation step).

  Next, an insulating film (SiN: film thickness 400 nm) 11 and a semiconductor film (a-Si (i): film thickness 130 nm, a-Si (n): film thickness 50 nm) are formed using a CVD apparatus. Next, the resist is patterned using a photoengraving apparatus. Next, dry etching is performed to remove the semiconductor film that is not protected by the resist. Next, a resist stripping process is performed to remove the resist. Thereby, the semiconductor layer 12 is formed (FIG. 3B; semiconductor layer forming step).

  Next, a Mo film is formed to a thickness of 300 nm using a sputtering apparatus. Next, the resist is patterned using a photoengraving apparatus. Next, a wet etching process is performed to remove the Mo film not protected by the resist. Next, dry etching is performed to remove the semiconductor film (a-Si (n)) that is not protected by the resist. Next, a resist stripping process is performed to remove the resist. Thus, the source / drain wiring 3 is formed (FIG. 3C; source / drain and channel formation step).

  Next, an insulating film (SiN: film thickness 100 nm) 13 is formed using a CVD apparatus (FIG. 3C). Next, a photosensitive organic resin film is formed by coating. Next, the organic flattening film 14 having the concavo-convex shape 14A is formed by a photolithography apparatus using a photomask for forming the concavo-convex pattern. Here, the concavo-convex shape 14 </ b> A is formed in the reflective portion 7 in which the reflective pixel electrode 6 is formed. At the same time, contact hole openings to be contact holes 9 are formed in the gate terminal portion, the source terminal portion, and the pixel / drain contact portion. Next, dry etching is performed to remove the insulating film 13 and the insulating film 11 at the contact hole opening (FIG. 3D; organic planarization film forming step). The process so far is substantially the same as the conventional process.

  Next, using a sputtering apparatus, a lower transparent conductive film (ITO (Indium Tin Oxide) film: film thickness 80 nm) 15, a metal film that is a reflective conductive film (Mo: film thickness 50 nm, AlCu: film thickness 300 nm) 16 are sequentially formed (FIG. 3E). The lower transparent conductive film 15 constitutes the transmissive pixel electrode 4. The reflective pixel electrode 6 is constituted by the metal film 16.

  Next, the resist 17 is patterned using a halftone exposure technique. Here, the thickness of the portion corresponding to the reflecting portion 7 of the resist 17 is thicker than the thickness corresponding to the transmitting portion 5. Here, the transmission part 5 is an area other than the reflection part 7 in the pixel area. Further, the thickness of the resist 17 in the region other than the reflective portion 7 and the portion other than the transmissive portion 5 where the resist 17 is left is equal to or greater than the thickness in the reflective portion 7.

  Next, a wet etching process for the metal film 16 is performed. In the first embodiment, isotropic etching is performed using the end face of the resist pattern. Therefore, the cross-sectional shape in the thickness direction of the metal film 16 is processed into a non-tapered shape. After the wet etching process for the metal film 16, a wet etching process for the lower transparent conductive film 15 is performed. In the first embodiment, the etching process is collectively performed with the same etching solution. Of course, it is also possible to etch each using a different chemical. As a result, the metal film 16 not covered with the resist 17 and the lower transparent conductive film 15 are removed (FIG. 3F).

  Next, an ashing process is performed to reduce the film thickness of the resist 17 and remove the resist 17 formed in the transmission part 5. Thereby, the metal film 16 of the transmission part 5 is exposed. At this time, the resist 17 having a reduced film remains on the reflecting portion 7. Further, the resist 17 having a reduced thickness remains in a region where the resist 17 having a thickness equal to or greater than that of the reflective portion 7 is formed. Accordingly, the metal film 16 of the reflecting portion 7 is covered with the resist 17.

  At the same time, in this step, the exposed organic planarization film 14 is partially removed in the film thickness direction. Therefore, for example, the film thickness of the organic planarization film 14 on the upper layer of the TFT 1 is reduced. Here, a sufficient level difference between the lower surface of the lower transparent conductive film 15 and the organic planarization film 14 removed by ashing is ensured. This is to prevent the upper transparent conductive film 18 laminated on the organic planarizing film 14 from coming into contact with the lower transparent conductive film 15 when the upper transparent conductive film 18 described later is formed. Specifically, it is desirable to provide a step of 100 nm or more due to the reduction of the organic planarization film 14 by ashing. In this embodiment, a step of 500 nm is provided (FIG. 3G).

  Next, a wet etching process is performed to remove the metal film 16 laminated on the transmission part 5. Thereby, the transmissive pixel electrode 4 and the reflective pixel electrode 6 are formed (FIG. 3H). Next, a resist stripping process is performed to remove the resist 17. Thereby, the reflective pixel electrode 6 is exposed. Next, an upper transparent conductive film (ITO film: film thickness 5 nm) 18 is formed (FIG. 3I). Thus, the TFT array substrate 100 is formed.

  FIG. 4 shows an enlarged view of the reflective portion 7 and the transmissive portion 5 including the pixel drain contact portion of FIG. In FIG. 4, the illustration of the uneven shape 14 </ b> A of the pixel drain contact portion and the reflective pixel electrode 6 is omitted.

  The film thickness of the upper transparent conductive film 18 is 5 nm, for example. The upper transparent conductive film 18 is divided and formed at a step portion on the TFT array substrate 100. For example, as shown in FIG. 4, the upper transparent conductive film 18 is divided at a step in the outer peripheral portion of the reflective pixel electrode 6 and the transmissive pixel electrode 4. That is, the upper transparent conductive film 18 is formed by being divided for each pixel.

  Further, as shown in FIG. 3I, the gate terminal portion and the end portion of the source terminal portion are similarly divided and formed. The steps in the outer peripheral portions of the reflective pixel electrode 6 and the transmissive pixel electrode 4 and the outer peripheral portions of the gate terminal portion and the source terminal portion are reduced by the metal film 16, the lower transparent conductive film 15, and the ashing process that constitute the reflective pixel electrode 6. This is the sum of the steps of the organic planarizing film 14. Therefore, the steps at the outer peripheral portions of the reflective pixel electrode 6 and the transmissive pixel electrode 4 and the outer peripheral portions of the gate terminal portion and the source terminal portion are much larger than the film thickness of the upper transparent conductive film 18. For this reason, the upper transparent conductive film 18 cannot overcome the steps at the outer peripheral portions of the reflective pixel electrode 6 and the transmissive pixel electrode 4 and the outer peripheral portions of the gate terminal portion and the source terminal portion.

  Specifically, in the first embodiment, the level difference between the surface of the organic planarization film 14 before the ashing process and the surface of the organic planarization film 14 reduced by the ashing process is approximately 500 nm. Therefore, the step in the outer periphery of the reflective pixel electrode 6 and the transmissive pixel electrode 4 and the outer periphery of the gate terminal portion and the source terminal portion is 930 nm. The film thickness of 5 nm of the upper transparent conductive film 18 is about 1/180 or less of the step. Therefore, the upper transparent conductive film 18 cannot get over the step. Therefore, without patterning the upper transparent conductive film 18, the upper transparent conductive film 18 on the reflective pixel electrode 6 and the upper transparent conductive film 18 formed at the step of the organic planarizing film 14 are electrically connected. Can be physically divided.

  Further, as shown in FIG. 3I, the area of the upper transparent conductive film 18 formed on the reflecting portion 7 is substantially the same as the area of the reflecting portion 7 or slightly smaller than the area of the reflecting portion 7. . The area of the upper transparent conductive film 18 formed on the transmission part 5 is substantially the same as the area of the transmission part 5 or slightly smaller than the area of the transmission part 5. In other words, as shown in FIG. 4, the position of the end portion of the upper transparent conductive film 18 on the reflective pixel electrode 6 at the boundary portion between the reflective portion 7 and the transmissive portion 5 is the pattern end of the reflective pixel electrode 6. It is located at the same position as the portion or inside the pattern end. Further, at the boundary portion between the reflective portion 7 and the transmissive portion 5, the position of the end portion of the upper transparent conductive film 18 on the transmissive pixel electrode 4 is the same position as the end portion of the transmissive portion 5 or the end portion of the transmissive portion 5. It is located inside the part. That is, the end portion of the upper transparent conductive film 18 does not extend laterally from the pattern end portion of the reflective pixel electrode 6, and does not have a bowl shape.

  The upper transparent conductive film 18 is formed of a material having substantially the same work function as the counter electrode 200C formed on the counter substrate 200. Here, “substantially the same work function” means that the difference is 02 or less, and the potential difference in the vicinity of both electrodes can be suppressed, and the effect can be exhibited more suitably. Therefore, the upper transparent conductive film 18 may be formed of the same material as the counter electrode 200C, for example. In the above example, the example in which ITO is used as the upper transparent conductive film 18 has been described, but it may be formed of a transparent conductive film such as IZO, ITZO, ITSO or the like.

  As described above, in the liquid crystal display device 400 and the method for manufacturing the liquid crystal display device 400 according to the first embodiment of the present invention, the organic planarization film 14 is formed on the TFT array substrate 100, and then the organic planarization film is formed. A transmissive pixel electrode 4 and a reflective pixel electrode 6 are formed on 14, and in the formation process, a step is formed in the organic planarization film 14, and then an upper transparent conductive film 18 is formed. Here, the upper transparent conductive film 18 is divided at the step of the organic planarization film 14. More specifically, the upper transparent conductive film 18 is divided at steps in the outer peripheral portions of the reflective pixel electrode 6 and the transmissive pixel electrode 4 and in the outer peripheral portions of the gate terminal portion and the source terminal portion. Further, the end portion of the upper transparent conductive film 18 does not extend laterally from the outer peripheral portions of the reflective pixel electrode 6 and the transmissive pixel electrode 4 and the outer peripheral portions of the gate terminal portion and the source terminal portion, and thus does not have a bowl shape. As a result, there is no conventional problem caused by a piece formed by peeling off the ridge-shaped portion of the transparent conductive film on the reflective pixel electrode in a subsequent process. Therefore, the yield of the liquid crystal display device 400 can be improved.

  In addition, the upper transparent conductive film 18 having substantially the same work function as the counter electrode 200 </ b> C is formed on the reflective pixel electrode 6. Thus, even if the reflective pixel electrode 6 is formed using a material different from the counter electrode 200C such as the metal film 16, flicker and burn-in do not occur. Therefore, the liquid crystal display device 400 with good display quality can be manufactured.

  Further, the upper transparent conductive film 18 is formed thinner than the step of the organic planarizing film 14. Therefore, the upper transparent conductive film 18 is formed so as to be divided at the level difference of the organic planarization film 14. That is, the upper transparent conductive film 18 is divided at the steps in the outer peripheral portions of the reflective pixel electrode 6 and the transmissive pixel electrode 4 and the outer peripheral portions of the gate terminal portion and the source terminal portion. Thereby, it is not necessary to pattern the upper transparent conductive film 18. Therefore, the etching process can be reduced. Thereby, manufacturing cost can be reduced.

  The upper transparent conductive film 18 is formed after the reflective pixel electrode 6 and the transmissive pixel electrode 4 are formed. Therefore, after the ashing process, only the metal film 16 to be the reflective pixel electrode 6 needs to be etched. Therefore, as in the example shown in FIG. 10, there is no restriction that the upper transparent conductive film 18 and the metal film 16 are etched while leaving the lower transparent conductive film 15 formed below the metal film 16. Thereby, a process freedom degree can be improved.

  In addition, the upper transparent conductive film 18 formed in the reduced portion of the organic planarizing film 14 forms a conductive layer over a wide range in the liquid crystal display device 400. Therefore, it has the effect of preventing static electricity damage that occurs during the panel assembly manufacturing process.

  In the first embodiment, the metal film 16 is left on the source terminal portion and the gate terminal portion. Specifically, a normal remaining pattern was used in the same manner as in the reflection region, instead of using a halftone exposure portion as in the patterning of the pixel electrode transmission portion. If halftone exposure is performed in a hole opening such as a contact hole having a depth such as a terminal portion, the resist film thickness tends to be non-uniform, and the halftone exposure process may become unstable. In the first embodiment, as described above, since the metal film 16 remains on the source terminal portion and the gate terminal portion, pattern defects can be reduced and the yield can be improved.

In the first embodiment, the single gap structure in which the transmissive pixel electrode 4 is formed on the organic planarizing film 14 is described as an example. However, the transmissive pixel electrode 4 is formed in a portion where the organic planarizing film 14 is removed. It may be a dual gap structure.
The materials for forming the gate wiring 2, the source / drain wiring 3, the reflective pixel electrode 6, the insulating films 11 and 13, and the transmissive pixel electrode 4 are not limited to the materials shown in the first embodiment. In particular, as the lower transparent conductive film 15 forming the transmissive pixel electrode 4, a transparent conductive film such as IZO, ITZO, ITSO or the like may be used in addition to ITO. In addition to a single layer structure, a multilayer structure may be used. The same applies to the upper transparent conductive film. Moreover, although the example which laminated | stacked the metal film of two layers was demonstrated as an example of a reflective conductive film, you may have a single layer structure and may laminate | stack three or more layers. The laminated films in the case of a multilayer structure may be the same type or different types. Note that the direct connection between the upper transparent conductive film and the lower transparent conductive film may be such that at least one layer is directly connected in the case of a laminated structure.
In the first embodiment, the liquid crystal display device 400 is exemplified by a transflective liquid crystal display device including both the reflective pixel electrode 6 and the transmissive pixel electrode 4. The present invention can also be applied to a reflective liquid crystal display device including only the electrode 6.
In the first embodiment, the organic planarization film 14 is exemplified as the base film, but the present invention is not limited to this.
In addition, the display material sandwiched between the first substrate and the second substrate is not limited to the liquid crystal material, and a display material such as an organic EL can also be applied.

[Embodiment 2]
Next, an example of a liquid crystal display device different from the first embodiment will be described. In the following description, the same reference numerals are assigned to the same element members as those in the above embodiment, and the description thereof is omitted as appropriate.

  The basic structure and manufacturing method of the liquid crystal display device according to the second embodiment are the same as those of the first embodiment except for the following points. That is, in the liquid crystal display device according to the first embodiment, the pattern side wall of the metal film, which is the reflective conductive film provided on the reflective pixel electrode, has a non-tapered shape, whereas the liquid crystal display according to the second embodiment. The apparatus is different in that the pattern side wall of the metal film, which is a reflective conductive film provided on the reflective pixel electrode, has a forward tapered shape. The liquid crystal display device according to the second embodiment is different in that the lower transparent conductive film and the upper transparent conductive film are in direct electrical and physical contact.

  FIG. 5 is a partial cross-sectional view of the liquid crystal display panel of the liquid crystal display device 400a according to the second embodiment. In FIG. 5, the illustration of the liquid crystal layer 300 sandwiched between the TFT array substrate 100a and the counter substrate 200, the sealant for keeping the distance between the TFT array substrate 100a and the counter substrate 200 constant, and the spacer are omitted. To do.

  The metal film 16a which is a reflective conductive film according to the present embodiment 2 has a forward tapered shape 19 on the pattern side wall. The lower transparent conductive film 15 to be the transmissive pixel electrode 4 is provided over substantially the entire pixel area except for the TFT 1 as in the first embodiment. In the second embodiment, the lower transparent conductive film 15 and the upper transparent conductive film 18a are in direct physical and electrical contact.

  Specifically, the lower transparent conductive film 15 located in the vicinity of the boundary with the step portion of the organic planarizing film 14 extends at least in an edge shape in a region partitioned outside the metal film 16a in plan view. A region A1 is provided. Then, the upper transparent conductive film 18a is covered so as to integrally cover the upper layer of the extension region A1, the pattern side wall of the forward tapered metal film 16a, and the entire upper layer of the metal film 16a. Thereby, the lower transparent conductive film 15 and the upper transparent conductive film 18a are in direct contact.

  Next, a manufacturing method of the TFT array substrate 100a of the liquid crystal display device 400a according to the second embodiment will be described with reference to FIGS. FIG. 6 is a process cross-sectional view illustrating a manufacturing process of the TFT array substrate 100a according to the second embodiment, and is a process cross-sectional view in the same region as FIG. 3 of the first embodiment. The steps from FIGS. 3A to 3E, that is, the process of forming the metal film 16a are the same as those in the first embodiment, and therefore illustration and description thereof are omitted.

  In the same manner as in the first embodiment, a lower transparent conductive film 15 and a metal film 16a are sequentially formed on the organic flattening film 14, and then a resist 17 is formed in the same manner as in the first embodiment using a halftone exposure technique. Is patterned. Thereafter, a wet etching process is performed on the metal film 16a. In the second embodiment, etching is performed using the resist pattern end face so that the side wall of the metal film 16a has a forward tapered shape. As the etching solution, for example, a mixed chemical solution of phosphoric acid, acetic acid, nitric acid and water can be used. A mixed chemical solution of phosphoric acid, acetic acid, nitric acid and water is also used as a general etching solution for Al, Mo, etc., but by etching the resist pattern end face by increasing the ratio of nitric acid as the composition ratio of the etching solution. The cross-sectional shape in the thickness direction of the film can be processed into a forward tapered shape. Thereby, the metal film 16a not protected by the resist 17 can be removed, and the pattern side wall can be tapered.

  Next, a wet etching process for the lower transparent conductive film 15 is performed. For example, oxalic acid can be used as the etchant. In some cases, a mixed chemical solution of hydrochloric acid, nitric acid and water may be used. As a result, the lower transparent conductive film 15 not protected by the resist 17 can be removed (see FIG. 6A).

  Subsequently, an ashing process is performed to reduce the film thickness of the resist 17 and remove the resist 17 formed in the transmission part 5. As a result, the metal film 16a of the transmission part 5 is exposed, and the resist 17 with the reduced film remains in the reflection part 7 (see FIG. 6B). Further, the resist 17 having a reduced thickness remains in a region where the resist 17 having a thickness equal to or greater than that of the reflective portion 7 is formed.

  At the same time, in this step, a part of the organic planarizing film 14 is removed in the film thickness direction (FIG. 6B). Therefore, for example, the film thickness of the organic planarization film 14 on the upper layer of the TFT 1 is reduced. Here, as in the first embodiment, a sufficient level difference between the lower surface of the lower transparent conductive film 15 and the organic planarization film 14 removed by ashing is ensured. Specifically, it is desirable to provide a step of 100 nm or more due to the reduction of the organic planarization film 14 by ashing. In this embodiment, a step of 500 nm is provided.

  Next, a wet etching process is performed to remove the metal film 16a laminated on the transmission part 5. Thereby, the transmissive pixel electrode 4 and the reflective pixel electrode 6a are formed (FIG. 6C). Next, a resist stripping process is performed to remove the resist 17. Thereby, the reflective pixel electrode 6a is exposed. Next, an upper transparent conductive film (ITO film: film thickness 5 nm) 18a is formed (FIG. 6D). Thus, the TFT array substrate 100a is formed.

  FIG. 7 is an enlarged view of the reflective portion 7 and the transmissive portion 5 including the pixel drain contact portion of FIG. 6D, and FIG. 8 is an enlarged view of the gate terminal portion and the source terminal portion. In FIG. 7, the illustration of the concavo-convex shape 14A of the pixel drain contact portion and the reflective pixel electrode 6a is omitted.

  The film thickness of the upper transparent conductive film 18a is, for example, 5 nm. As described above, the upper transparent conductive film 18a is in direct contact with the lower transparent conductive film 15. On the other hand, as shown in FIG. 7, the upper transparent conductive film 18a is divided and formed at a step portion with the organic planarization film 14 on the TFT array substrate 100a. That is, the upper transparent conductive film 18a is formed by being divided for each pixel. Similarly, the end portions of the gate terminal portion and the source terminal portion are separated and formed at the step portion with respect to the organic planarization film 14.

  The steps at the outer peripheral portion of the transmissive pixel electrode 4 and the outer peripheral portions of the gate terminal portion and the source terminal portion are the sum of the steps of the lower transparent conductive film 15 and the organic planarization film 14 reduced by ashing. Therefore, the steps in the outer peripheral portion of the transmissive pixel electrode 4 and the outer peripheral portions of the gate terminal portion and the source terminal portion are much larger than the film thickness of the upper transparent conductive film 18a. Therefore, the upper transparent conductive film 18a cannot get over the steps in the outer peripheral portion of the transmissive pixel electrode 4 and the outer peripheral portions of the gate terminal portion and the source terminal portion. Further, as shown in FIGS. 7 and 8, the end portion of the upper transparent conductive film 18a does not extend laterally from the pattern end portion of the reflective pixel electrode 6a and is not in the shape of a bowl.

  According to the second embodiment, similarly to the first embodiment, there is no problem caused by a piece formed by peeling off the ridge-shaped portion of the transparent conductive film on the reflective pixel electrode in a subsequent process. Therefore, the yield of the liquid crystal display device can be improved. Further, since flicker and burn-in do not occur, the liquid crystal display device 400 with good display quality can be manufactured. Further, since it is not necessary to pattern the upper transparent conductive film 18a, the etching process can be reduced. Further, unlike the example shown in FIG. 10, there is no process of etching the upper transparent conductive film and the metal film while leaving the lower transparent conductive film formed in the lower layer of the metal film. The degree can be improved. Moreover, since the upper transparent conductive film 18a is formed over a wide range, it has an effect of preventing static electricity damage that occurs during the panel assembly manufacturing process.

  Further, according to the second embodiment, the pattern side wall of the metal film 16a is tapered, and at least the edge-shaped extension region A1 of the lower transparent conductive film 15 is formed in a region partitioned outside the metal film 16a. Is forming. Then, the upper transparent conductive film 18a is integrally formed on the pattern side wall of the metal film 16a and the extending region A1 of the lower transparent conductive film 15 from the upper layer of the metal film 16a. Thereby, the upper transparent conductive film 18a and the lower transparent conductive film 15 are in direct contact. As a result, the electrical resistance of each electrode and terminal contact surface can be lowered, and the choice of material for the reflective electrode can be expanded. For this reason, process freedom improves. For example, when selecting the metal film 16a in contact with the upper transparent conductive film 18a, it is possible to select a material having a high electric resistance at the interface. Therefore, a material having high reflectance can be selected preferentially as the material of the metal film 16a, and a bright display device having excellent reflectance can be provided. Conversely, if the brightness is the same, the power consumption of the device can be reduced.

  In the second embodiment, as a method of directly contacting the upper transparent conductive film 18a and the lower transparent conductive film 15, the pattern side wall of the metal film that is the reflective conductive film is tapered, and An extended region A1 of the edge-shaped lower transparent conductive film 15 is formed in a region partitioned outside the metal film 16a, and extends over the extended region A1, the pattern side wall of the metal film 16a, and the upper layer of the metal film 16a. The upper transparent conductive film 18a is integrally covered with the upper transparent conductive film 18a. However, the upper transparent conductive film 18a and the lower transparent conductive film 15 need only be in direct contact with each other and do not depart from the spirit of the present invention. Various modifications are possible. For example, as the lower transparent conductive film 15, the example in which the pattern side wall has a non-tapered shape has been described, but the pattern side wall of the lower transparent conductive film 15 has a forward tapered shape like the metal film 16 a, and the lower transparent conductive film 15 The upper transparent conductive film and the lower transparent conductive film may be brought into direct contact with each other by covering the patterned side wall of the conductive film and the tapered pattern side wall of the metal film with the upper transparent conductive film.

  Further, as shown in FIG. 6A, the pattern edge of the resist 17 has a slightly ridge shape corresponding to the amount of the metal film 16a processed into a taper shape. Since the reflective pixel electrode 6a is formed and then removed, there is no particular problem. 3 and 10, the pattern edge of the resist 17 has a slightly bowl shape (not shown), but is similarly removed when the transmissive pixel electrode 4 and the reflective pixel electrode 6 are formed. Therefore, there is no particular problem.

3 is a partial cross-sectional view showing a liquid crystal display panel portion of the liquid crystal display device according to Embodiment 1. FIG. 3 is a plan view showing a configuration of a pixel of the TFT array substrate according to Embodiment 1. FIG. FIG. 6 is a process cross-sectional view illustrating the manufacturing process of the TFT array substrate according to the first embodiment. It is sectional drawing which expands and shows the reflection part and transmission part containing the pixel drain contact part of FIG.3 (i). FIG. 10 is a process cross-sectional view illustrating a manufacturing process of a TFT array substrate according to the second embodiment. FIG. 10 is a process cross-sectional view illustrating a manufacturing process of a TFT array substrate according to the second embodiment. It is sectional drawing which expands and shows the reflection part and transmission part containing the pixel drain contact part of FIG.6 (d). It is sectional drawing which expands and shows the gate terminal and source terminal of FIG.6 (d). It is process sectional drawing which shows the manufacturing process of the conventional TFT array substrate typically. It is process sectional drawing which shows the manufacturing process of the conventional TFT array substrate.

Explanation of symbols

4 transmissive pixel electrode 5 transmissive portion 6 reflective pixel electrode 7 reflective portion 14 Organic planarization film (underlying film)
15 Lower transparent conductive film 16 Metal film 17 Resist 18 Upper transparent conductive film (transparent conductive film)
19 Tapered shape 100 TFT array substrate (first substrate)
200 Counter substrate (second substrate)
200C Counter electrode 300 Liquid crystal layer (display material)
400 Liquid crystal display device (display device)

Claims (12)

A display device comprising: a first substrate; a second substrate disposed opposite to the first substrate; and a display material sandwiched between the first substrate and the second substrate. A manufacturing method of
Forming a base film on the first substrate;
Forming a reflective pixel electrode on the base film;
Forming a step in the base film;
And a step of forming an upper transparent conductive film so as to be divided at a step of the base film after the step of forming the reflective pixel electrode. Forming a transmissive pixel electrode on the first substrate so as to protrude from the pattern of the reflective pixel electrode;
2. The display according to claim 1, wherein, in the step of forming the upper transparent conductive film, the upper transparent conductive film is formed on at least the reflective pixel electrode and the transmissive pixel electrode. Device manufacturing method.   The display according to claim 1, wherein in the step of forming the reflective pixel electrode, at least one layer of a reflective conductive film is formed, and etching is performed so that a pattern side wall of the reflective conductive film has a forward tapered shape. Device manufacturing method. In the step of forming the transmissive pixel electrode, a lower transparent conductive film is formed as a lower layer of the reflective conductive film and an upper layer of the base film,
In the step of forming the upper transparent conductive film, the upper transparent conductive film is formed on a pattern side wall of the reflective conductive film so that the lower transparent conductive film and the upper transparent conductive film are in direct contact with each other. The method for manufacturing a display device according to claim 3, wherein the conductive film is coated. The second substrate has a counter electrode provided on the first substrate side,
The display device manufacturing method according to claim 1, wherein the upper transparent conductive film has substantially the same work function as the counter electrode.   The display device manufacturing method according to claim 1, wherein the upper transparent conductive film is formed to be thinner than a step of the base film. A first substrate;
A second substrate disposed opposite the first substrate;
A display material sandwiched between the first substrate and the second substrate;
An underlying film formed on the first substrate and having a step;
A reflective pixel electrode formed on the base film;
An upper transparent conductive film formed on the reflective pixel electrode by being divided at the step of the base film,
A display device comprising: A transmissive pixel electrode formed on the first substrate so as to protrude from the pattern of the reflective pixel electrode;
The display device according to claim 7, wherein the upper transparent conductive film is formed at least above the reflective pixel electrode and the transmissive pixel electrode. The reflective pixel electrode is composed of at least one layer of a reflective conductive film,
The display device according to claim 7, wherein a pattern side wall of the reflective conductive film has a forward tapered shape. The transmissive pixel electrode is an upper layer of the base film, and includes a lower transparent conductive film formed in a lower layer of the reflective conductive film,
From the upper layer of the reflective conductive film, the pattern sidewall of the reflective conductive film, and the pattern sidewall of the reflective conductive film so that the upper transparent conductive film and the lower transparent conductive film are in direct contact with each other The display device according to claim 9, wherein the upper transparent conductive film is covered over the extended lower transparent conductive film. The second substrate has a counter electrode provided on the first substrate side,
The display device according to claim 7, wherein the transparent conductive film has substantially the same work function as the counter electrode.   The display device according to claim 7, wherein the transparent conductive film is thinner than a step of the base film.

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