Liquid crystal display device and method of manufacturing the same

Abstract

To suppress damage of a terminal part due to an etchant for forming a reflection electrode in a liquid crystal display device in which each pixel includes a reflection region.SOLUTION: The first substrate of the liquid crystal display device includes a TFT provided in each pixel, a transparent electrode electrically connected to the TFT, a reflective electrode provided on a portion of the transparent electrode located in the reflective region, and a terminal portion disposed in the non-display region. The terminal portion includes a lower conductive layer formed in the same layer as a gate electrode of the TFT, an intermediate conductive layer formed of a transparent conductive material and covering the lower conductive layer, and an upper conductive layer formed in the same layer as the transparent electrode, and does not include a conductive layer formed in the same layer as a source electrode and a drain electrode of the TFT.SELECTED DRAWING: Figure 3B

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device in which each pixel includes a reflective region. The present invention also relates to a method for manufacturing a liquid crystal display device. [Background technology]

[0002] Liquid crystal display devices are generally broadly classified into transmissive and reflective liquid crystal display devices. Transmissive liquid crystal display devices perform display in transmissive mode using light emitted from a backlight. Reflective liquid crystal display devices perform display in reflective mode using ambient light. Liquid crystal display devices have also been proposed in which each pixel includes a reflective region for displaying in reflective mode and a transmissive region for displaying in transmissive mode. Such liquid crystal display devices are called transflective or transflective liquid crystal display devices.

[0003] Reflective and semi-transmissive liquid crystal display devices are suitable for use, for example, as small to medium-sized display devices for mobile outdoor applications. A reflective liquid crystal display device is disclosed, for example, in Patent Document 1. A semi-transmissive liquid crystal display device is disclosed, for example, in Patent Document 2.

[0004] Furthermore, the active matrix substrate of the liquid crystal display device has terminal sections in the non-display area for connecting gate wiring and source wiring to input terminals of a drive circuit. The terminal sections have a laminated structure in which multiple conductive layers are stacked. Various structures have been proposed as the laminated structure of the terminal sections. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-122094 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-131268 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the research conducted by the inventors of the present application, it has been found that in reflective and semi-transmissive liquid crystal display devices, depending on the laminated structure adopted in the terminal portion, the conductive layer constituting the terminal portion may be damaged by the etchant used in forming the reflective electrode.

[0007] The embodiments of the present invention have been made in consideration of the above problems, and their purpose is to suppress damage to terminal portions caused by etchant used to form reflective electrodes in liquid crystal display devices in which each pixel includes a reflective region. [Means for solving the problem]

[0008] This specification discloses a liquid crystal display device and a method for manufacturing a liquid crystal display device described in the following items.

[0009] [Item 1] a first substrate; a second substrate facing the first substrate; a liquid crystal layer provided between the first substrate and the second substrate; Equipped with A liquid crystal display device having a display area including a plurality of pixels arranged in a matrix including a plurality of rows and a plurality of columns, and a non-display area located around the display area, Each of the plurality of pixels includes a reflective region that displays in a reflective mode; The first substrate is a thin film transistor provided in each of the plurality of pixels; a transparent electrode electrically connected to the thin film transistor; a reflective electrode provided on a portion of the transparent electrode located within the reflective region; a terminal portion disposed in the non-display area; and The thin film transistor is a semiconductor layer including a channel region and a source region and a drain region located on both sides of the channel region; a gate electrode facing the channel region via a gate insulating layer; a source electrode electrically connected to the source region of the semiconductor layer; a drain electrode electrically connected to the drain region of the semiconductor layer; and The terminal portion is a lower conductive layer formed in the same layer as the gate electrode; an intermediate conductive layer formed of a transparent conductive material and covering the lower conductive layer; an upper conductive layer formed in the same layer as the transparent electrode; and The liquid crystal display device does not include a conductive layer formed in the same layer as the source electrode and the drain electrode.

[0010] [Item 2] Item 2. The liquid crystal display device according to item 1, wherein the thin film transistor further includes a protective conductive layer formed in the same layer as the intermediate conductive layer and covering the gate electrode.

[0011] [Item 3] The first substrate is an interlayer insulating layer covering the thin film transistor; an organic insulating layer provided on the interlayer insulating layer; and the transparent electrode is provided on the organic insulating layer, a first contact hole exposing a portion of the drain electrode is formed in the interlayer insulating layer and the organic insulating layer; 3. The liquid crystal display device according to item 1 or 2, wherein the transparent electrode is connected to the drain electrode through the first contact hole.

[0012] [Item 4] the gate electrode is disposed below the semiconductor layer, a second contact hole exposing a portion of the intermediate conductive layer is formed in the gate insulating layer and the interlayer insulating layer; Item 4. The liquid crystal display device according to item 3, wherein the upper conductive layer is connected to the intermediate conductive layer through the second contact hole.

[0013] [Item 5] a portion of the organic insulating layer located in the reflective region has an uneven surface structure; Item 5. The liquid crystal display device according to item 3 or 4, wherein the portion of the transparent electrode located within the reflective region and the reflective electrode each have a concave-convex surface structure that reflects the concave-convex surface structure of the organic insulating layer.

[0014] [Item 6] 6. The liquid crystal display device according to any one of items 1 to 5, wherein the first substrate has a further transparent electrode provided on the reflective electrode.

[0015] [Item 7] a first substrate; a second substrate facing the first substrate; a liquid crystal layer provided between the first substrate and the second substrate; Equipped with A liquid crystal display device having a display area including a plurality of pixels arranged in a matrix including a plurality of rows and a plurality of columns, and a non-display area located around the display area, Each of the plurality of pixels includes a reflective region that displays in a reflective mode; The first substrate is a thin film transistor provided in each of the plurality of pixels; a transparent electrode electrically connected to the thin film transistor; a reflective electrode provided on a portion of the transparent electrode located within the reflective region; a terminal portion disposed in the non-display area; and The thin film transistor is a semiconductor layer including a channel region and a source region and a drain region located on both sides of the channel region; a gate electrode facing the channel region via a gate insulating layer; a source electrode electrically connected to the source region of the semiconductor layer; a drain electrode electrically connected to the drain region of the semiconductor layer; and The terminal portion is a lower conductive layer formed in the same layer as the source electrode and the drain electrode; an intermediate conductive layer formed of a transparent conductive material and covering the lower conductive layer; an upper conductive layer formed in the same layer as the transparent electrode; and The liquid crystal display device does not include a conductive layer formed in the same layer as the gate electrode.

[0016] [Item 8] 8. The liquid crystal display device according to item 7, wherein the terminal portion includes an underlying semiconductor layer formed in the same layer as the semiconductor layer and positioned below the underlying conductive layer.

[0017] [Item 9] The first substrate is an interlayer insulating layer covering the thin film transistor; an organic insulating layer provided on the interlayer insulating layer; and the transparent electrode is provided on the organic insulating layer, a first contact hole exposing a portion of the drain electrode is formed in the interlayer insulating layer and the organic insulating layer; Item 9. The liquid crystal display device according to item 7 or 8, wherein the transparent electrode is connected to the drain electrode through the first contact hole.

[0018] [Item 10] a second contact hole is formed in the interlayer insulating layer to expose a portion of the intermediate conductive layer; Item 10. The liquid crystal display device according to item 9, wherein the upper conductive layer is connected to the intermediate conductive layer through the second contact hole.

[0019] [Item 11] a portion of the organic insulating layer located in the reflective region has an uneven surface structure; Item 11. The liquid crystal display device according to item 9 or 10, wherein the portion of the transparent electrode located within the reflective region and the reflective electrode each have a concave-convex surface structure that reflects the concave-convex surface structure of the organic insulating layer.

[0020] [Item 12] Item 12. The liquid crystal display device according to any one of items 7 to 11, wherein the first substrate has a further transparent electrode provided on the reflective electrode.

[0021] [Item 13] A method for manufacturing a liquid crystal display device according to item 1, The step of fabricating the first substrate includes: (a) forming the thin film transistor on a substrate; a step (b) of forming an interlayer insulating layer covering the thin film transistor; (c) forming an organic insulating layer on the interlayer insulating layer; (d) forming the transparent electrode on the organic insulating layer; Step (e) of forming the reflective electrode on a portion of the transparent electrode located within the reflective region; It encompasses The step (a) of forming the thin film transistor comprises: a step (a1) of depositing a semiconductor film on the gate insulating layer; a step (a2) of depositing a source conductive film on the semiconductor film; a step (a3) ​​of forming the semiconductor layer, the source electrode, and the drain electrode by patterning the semiconductor film and the source conductive film by a photolithography process using a multi-tone photomask; A method for manufacturing a liquid crystal display device, comprising:

[0022] [Item 14] the organic insulating layer has an opening overlapping a portion of the drain electrode, a portion of the organic insulating layer located in the reflective region has an uneven surface structure; The step (c) of forming the organic insulating layer comprises: a step (c1) of applying a photosensitive resin material onto the interlayer insulating layer; a step (c2) of pattern-exposing the applied photosensitive resin material using a multi-tone photomask; a step (c3) of developing the pattern-exposed photosensitive resin material; Item 14. The method according to Item 13, comprising:

[0023] [Item 15] the step (a) of forming the thin film transistor further includes the step (a4) of forming the gate electrode; In the step (a4) of forming the gate electrode, the lower conductive layer of the terminal portion is formed together with the gate electrode, Item 15. The manufacturing method according to item 13 or 14, wherein in the step (d) of forming the transparent electrode, the upper conductive layer of the terminal portion is formed together with the transparent electrode.

[0024] [Item 16] the step (a) of forming the thin film transistor further includes a step (a5) of forming a protective conductive layer covering the gate electrode; Item 16. The manufacturing method according to Item 15, wherein in the step (a5) of forming the protective conductive layer, the intermediate conductive layer of the terminal portion is formed together with the protective conductive layer.

[0025] [Item 17] Item 7 is a method for manufacturing a liquid crystal display device according to item 7, The step of fabricating the first substrate includes: (a) forming the thin film transistor on a substrate; a step (b) of forming an interlayer insulating layer covering the thin film transistor; (c) forming an organic insulating layer on the interlayer insulating layer; (d) forming the transparent electrode on the organic insulating layer; Step (e) of forming the reflective electrode on a portion of the transparent electrode located within the reflective region; It encompasses The step (a) of forming the thin film transistor comprises: a step (a1) of depositing a semiconductor film on the gate insulating layer; a step (a2) of depositing a source conductive film on the semiconductor film; a step (a3) ​​of forming the semiconductor layer, the source electrode, and the drain electrode by patterning the semiconductor film and the source conductive film by a photolithography process using a multi-tone photomask; A method for manufacturing a liquid crystal display device, comprising:

[0026] [Item 18] the organic insulating layer has an opening overlapping a portion of the drain electrode, a portion of the organic insulating layer located in the reflective region has an uneven surface structure; The step (c) of forming the organic insulating layer comprises: a step (c1) of applying a photosensitive resin material onto the interlayer insulating layer; a step (c2) of pattern-exposing the applied photosensitive resin material using a multi-tone photomask; a step (c3) of developing the pattern-exposed photosensitive resin material; Item 18. The method according to Item 17, comprising:

[0027] [Item 19] In the step (a3) ​​of forming the semiconductor layer, the source electrode, and the drain electrode, the lower conductive layer of the terminal portion is formed together with the source electrode and the drain electrode; Item 19. The manufacturing method according to item 17 or 18, wherein in the step (d) of forming the transparent electrode, the upper conductive layer of the terminal portion is formed together with the transparent electrode.

[0028] [Item 20] Item 20. The manufacturing method according to Item 19, wherein in the step (a3) ​​of forming the semiconductor layer, the source electrode, and the drain electrode, an underlying semiconductor layer located below the underlying conductive layer in the terminal portion is also formed.

[0029] [Item 21] 21. The method according to any one of items 17 to 20, further comprising the step (f) of forming the intermediate conductive layer of the terminal portion after the step (a) of forming the thin film transistor. [Effects of the Invention]

[0030] According to the embodiment of the present invention, in a liquid crystal display device in which each pixel includes a reflective region, damage to the terminal portion caused by an etchant used to form a reflective electrode can be suppressed. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a plan view schematically showing a liquid crystal display device 100 according to an embodiment of the present invention. [Figure 2A] 1 is a plan view schematically illustrating a liquid crystal display device 100, showing a region corresponding to one pixel P. FIG. [Figure 2B] 1 is a cross-sectional view schematically illustrating a liquid crystal display device 100, showing a region corresponding to one pixel P. FIG. [Figure 3A] 1 is a plan view schematically showing a terminal portion Ta of a TFT substrate 10 of a liquid crystal display device 100. FIG. [Figure 3B] FIG. 2 is a cross-sectional view schematically showing a terminal portion Ta. [Figure 4A] 1 is a cross-sectional view schematically showing a TFT substrate 910 of a comparative example, showing a region corresponding to a pixel P. FIG. [Figure 4B] 10 is a cross-sectional view schematically showing a terminal portion 910Ta of a TFT substrate 910 of a comparative example. FIG. [Figure 5] 10A and 10B are diagrams for explaining why a terminal portion 910Ta of a TFT substrate 910 of a comparative example is damaged. [Figure 6A] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 6B] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 6C] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 6D] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 6E] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 6F] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 6G] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 6H] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 7A] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 7B] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 7C] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 7D] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 7E] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 7F] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 7G] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 7H] 2A to 2C are cross-sectional views illustrating steps for manufacturing the TFT substrate 10. FIG. [Figure 8A] 1 is a cross-sectional view schematically illustrating another liquid crystal display device 100A according to a preferred embodiment of the present invention, showing a region corresponding to one pixel P. FIG. [Figure 8B]1 is a cross-sectional view schematically showing a terminal portion TaA of a TFT substrate 10 of a liquid crystal display device 100A. [Figure 9A] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 9B] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 9C] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 9D] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 9E] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 9F] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 9G] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 9H] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 10A] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 10B] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 10C] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 10D] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 10E] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 10F] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 10G] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. [Figure 10H] 1A to 1C are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. DETAILED DESCRIPTION OF THE INVENTION

[0032] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. A reflective liquid crystal display device will be exemplified as an embodiment of the present invention.

[0033] A liquid crystal display device 100 according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a plan view schematically showing the liquid crystal display device 100.

[0034] As shown in Fig. 1, the liquid crystal display device 100 has a display region DR and a non-display region (peripheral region) FR located around the display region DR. The display region DR includes a plurality of pixels P. The plurality of pixels P are arranged in a matrix having a plurality of rows and a plurality of columns. Each pixel P includes a thin film transistor (TFT) 2 and a pixel electrode PE.

[0035] 2A and 2B, the liquid crystal display device 100 will be described in more detail. 2A and 2B are a plan view and a cross-sectional view, respectively, that schematically show the liquid crystal display device 100, and show a region corresponding to one pixel P.

[0036] As shown in FIG. 2B , the liquid crystal display device 100 includes an active matrix substrate (hereinafter referred to as a "TFT substrate") 10, a counter substrate (also referred to as a "color filter substrate") 20 that faces the TFT substrate 10, and a liquid crystal layer 30 provided between the TFT substrate 10 and the counter substrate 20. Each pixel P of the liquid crystal display device 100 includes a reflective region that performs display in a reflective mode using ambient light. Since the liquid crystal display device 100 of this embodiment is a reflective type, the entire region of each pixel P that contributes to display is a reflective region.

[0037] 1 and 2A, the TFT substrate 10 has a plurality of gate lines (scanning lines) GL extending in the row direction, a plurality of source lines (signal lines) SL extending in the column direction, a TFT 2 provided in each pixel P, and a pixel electrode PE electrically connected to the TFT 2. The gate lines GL and the like are supported by an insulating substrate 1. The substrate 1 is, for example, a glass substrate.

[0038] The TFT 2 has a gate electrode 3, a gate insulating layer 4, a semiconductor layer 5, a source electrode 6, and a drain electrode 7. The semiconductor layer 5 includes a channel region 5c and a source region 5s and a drain region 5d located on either side of the channel region 5c. Here, the semiconductor layer 5 is an amorphous silicon layer, but the material of the semiconductor layer 5 is not limited to amorphous silicon. Although not shown here, the semiconductor layer 5 also includes an intrinsic semiconductor layer and an impurity-doped semiconductor layer whose resistance is reduced by doping with impurities. The impurity-doped semiconductor layer is provided on the intrinsic semiconductor layer. The impurity-doped semiconductor layer is formed in the source region 5s and the drain region 5d, but not in the channel region 5c. The intrinsic semiconductor layer is formed in the channel region 5c, the source region 5s, and the drain region 5d.

[0039] The gate electrode 3 is disposed below the semiconductor layer 5 (i.e., between the semiconductor layer 5 and the substrate 1) and faces the channel region 5c of the semiconductor layer 5 via the gate insulating layer 4. The gate electrode 3 is electrically connected to the corresponding gate wiring GL, and receives a gate signal (scanning signal) from the gate wiring GL. In the illustrated example, the gate electrode 3 is formed integrally with the gate wiring GL. More specifically, a region of the gate wiring GL that overlaps with the semiconductor layer 5 in a plan view functions as the gate electrode 3.

[0040] In the illustrated example, the TFT 2 further includes a conductive layer 11 covering the gate electrode 3. Hereinafter, this conductive layer 11 will be referred to as a "protective conductive layer." The protective conductive layer 11 is made of a transparent conductive material.

[0041] The gate insulating layer 4 is formed so as to cover the gate electrode 3 and the protective conductive layer 11. The semiconductor layer 5 is provided on the gate insulating layer 4.

[0042] The source electrode 6 is provided on the semiconductor layer 5. The source electrode 6 is in contact with the source region 5s of the semiconductor layer 5 and is electrically connected to the source region 5s. The source electrode 6 is also electrically connected to a corresponding source line SL, and a source signal (display signal) is applied to the source electrode 6 from the source line SL. In the illustrated example, the source electrode 6 is formed integrally with the source line SL. More specifically, the source electrode 6 extends from the source line SL.

[0043] The drain electrode 7 is provided on the semiconductor layer 5 and the gate insulating layer 4. The drain electrode 7 is in contact with the drain region 5d of the semiconductor layer 5 and is electrically connected to the drain region 5d. The drain electrode 7 is also electrically connected to the pixel electrode PE. The drain electrode 7 is formed in the same layer as the source line SL and the source electrode 7 (i.e., made of the same conductive film).

[0044] In the illustrated example, the source electrode 6 has a laminated structure including a lower layer 6a and an upper layer 6b formed on the lower layer 6a, and similarly, the drain electrode 7 has a laminated structure including a lower layer 7a and an upper layer 7b formed on the lower layer 7a. The lower layers 6a and 7a of the source electrode 6 and the drain electrode 7 are, for example, Ti layers, and the upper layers 6b and 7b of the source electrode 6 and the drain electrode 7 are, for example, Cu layers, but are not limited to these. Also, the source electrode 6 and the drain electrode 7 do not necessarily have a laminated structure.

[0045] An interlayer insulating layer (passivation layer) 8 is provided so as to cover the TFT 2. The interlayer insulating layer 8 is, for example, an inorganic insulating layer.

[0046] An organic insulating layer (planarizing layer) 9 is provided on the interlayer insulating layer 8. A portion of the surface of the organic insulating layer 9 (specifically, a portion located in the reflective region) has an uneven shape. In other words, the portion of the organic insulating layer 9 located in the reflective region has an uneven surface structure. The organic insulating layer 9 having an uneven surface structure can be formed using a photosensitive resin material, for example, as described in Japanese Patent No. 3394926.

[0047] As shown in FIG. 2B, the pixel electrode PE includes a first transparent electrode TE1, a reflective electrode RE, and a second transparent electrode TE2.

[0048] The first transparent electrode TE1 is provided on the organic insulating layer 9. The first transparent electrode TE1 is made of a transparent conductive material (e.g., ITO). The first transparent electrode TE1 is electrically connected to the TFT2. In the example shown, a first contact hole CH1 that exposes a portion of the drain electrode 7 is formed in the interlayer insulating layer 8 and the organic insulating layer 9, and the first transparent electrode TE1 is connected to the drain electrode 7 through this first contact hole CH1.

[0049] The reflective electrode RE is provided on a portion of the first transparent electrode TR1 located in the reflective region, but is not provided on a portion of the first transparent electrode TR1 located in the first contact hole CH1. The reflective electrode RE is made of a metal material with high reflectivity (e.g., aluminum or silver). The reflective electrode RE is in contact with the first transparent electrode TE1 and is electrically connected to the drain electrode 7 of the TFT2 via the first transparent electrode TE1.

[0050] The second transparent electrode TE2 is provided on the reflective electrode RE. The second transparent electrode TE2 is made of a transparent conductive material (e.g., ITO). The second transparent electrode TE2 is in contact with the reflective electrode RE and is electrically connected to the drain electrode 7 of the TFT2 via the reflective electrode RE and the first transparent electrode TE1.

[0051] The portion of the first transparent electrode TE1 located within the reflective region, the reflective electrode RE, and the second transparent electrode TE2 each have an uneven surface structure that reflects the uneven surface structure of the organic insulating layer 9. The uneven surface structure of the reflective electrode RE can diffusely reflect ambient light, achieving a display that is close to paper white. The uneven surface structure can be composed of, for example, multiple protrusions p randomly arranged so that the center-to-center spacing between adjacent protrusions p is 5 μm to 50 μm, preferably 10 μm to 20 μm. When viewed from the normal direction of the substrate 1, the shape of the protrusions p is approximately circular or polygonal. The area of ​​the protrusions p in the pixel P is, for example, approximately 20% to 40%. The height of the protrusions p is, for example, 1 μm to 5 μm.

[0052] The counter substrate 20 has a counter electrode (common electrode) CE. The counter electrode CE is made of a transparent conductive material (e.g., ITO). The counter electrode CE faces the pixel electrodes PE. A voltage (common voltage) common to a plurality of pixels P is applied to the counter electrode CE.

[0053] Although not shown here, the counter substrate 20 typically further includes a light-shielding layer (black matrix) and a color filter layer. The light-shielding layer is formed in a substantially lattice pattern. The color filter layer typically includes red, green, and blue color filters.

[0054] The above-mentioned counter electrode CE and the like are supported by a transparent, insulating substrate 21. The substrate 21 is, for example, a glass substrate.

[0055] A pair of alignment films (not shown) are provided on the outermost surfaces of the TFT substrate 10 and the counter substrate 20 on the liquid crystal layer 30 side. The pair of alignment films may be horizontal alignment films or vertical alignment films depending on the display mode.

[0056] The thickness of the liquid crystal layer 30 can be determined by a plurality of columnar spacers (not shown), which are made of a photosensitive resin material.

[0057] 1, the TFT substrate 10 further has a plurality of terminal portions Ta arranged in the non-display region FR. Each gate line GL is connected to a gate driver (not shown) via a corresponding terminal portion Ta, and each source line SL is connected to a source driver (not shown) via a corresponding terminal portion Ta.

[0058] The structure of the terminal portion Ta will be described with reference to Figures 3A and 3B, which are a plan view and a cross-sectional view schematically showing the terminal portion Ta.

[0059] 3A and 3B, the terminal portion Ta includes a lower conductive layer (first conductive layer) 12, an intermediate conductive layer (second conductive layer) 13, and an upper conductive layer (third conductive layer) 14. The lower conductive layer 12, the intermediate conductive layer 13, and the upper conductive layer 14 are stacked in this order from the substrate 1 side.

[0060] The lower conductive layer 12 is formed in the same layer as the gate electrode 3 (i.e., made of the same conductive film as the gate electrode 3). The intermediate conductive layer 13 covers the lower conductive layer 12 and is formed in the same layer as the protective conductive layer 11 (i.e., made of the same conductive film as the protective conductive layer 11). Therefore, the intermediate conductive layer 13 is formed from a transparent conductive material.

[0061] The upper conductive layer 14 is formed in the same layer as the first transparent electrode TE1 (i.e., from the same conductive film as the first transparent electrode TE1). A second contact hole CH2 exposing a portion of the intermediate conductive layer 13 is formed in the gate insulating layer 4 and the interlayer insulating layer 8, and the upper conductive layer 14 is connected to the intermediate conductive layer 13 at the second contact hole CH2. Therefore, the lower conductive layer 12, the intermediate conductive layer 13, and the upper conductive layer 14 are electrically connected to one another.

[0062] Furthermore, the terminal portion Ta does not include a conductive layer formed in the same layer as the source electrode 6 and the drain electrode 7. In other words, the terminal portion Ta does not include a conductive layer formed from the same conductive film as the source electrode 6 and the drain electrode 7.

[0063] The liquid crystal display device 100 according to the embodiment of the present invention has the above-described structure, and thus can suppress damage to the terminal portion Ta caused by the etchant used in forming the reflective electrode RE. The reason for this will be explained below with reference to the structure of a TFT substrate 910 of a comparative example shown in Figures 4A and 4B.

[0064] Fig. 4A is a cross-sectional view schematically showing a TFT substrate 910 of the comparative example, and shows a region corresponding to a pixel P. Fig. 4B is a cross-sectional view schematically showing a terminal portion 910Ta of the TFT substrate 910 of the comparative example.

[0065] 4A, the TFT substrate 910 of the comparative example differs from the TFT substrate 10 of the liquid crystal display device 100 in that the TFT 902 does not have a protective conductive layer covering the gate electrode 3. Furthermore, the TFT substrate 910 of the comparative example differs from the terminal portion Ta of the TFT substrate 10 of the liquid crystal display device 100 in the structure of the terminal portion 910Ta, as shown in FIG.

[0066] The terminal portion 910Ta of the TFT substrate 910 of the comparative example includes a first conductive layer 912, a second conductive layer 913, a third conductive layer 914, and a fourth conductive layer 915. The first conductive layer 912, the second conductive layer 913, the third conductive layer 914, and the fourth conductive layer 915 are stacked in this order from the substrate 1 side.

[0067] The first conductive layer 912 is formed in the same layer as the gate electrode 3. The second conductive layer 913 is formed in the same layer as the source electrode 6 and the drain electrode 7. Therefore, the second conductive layer 913 has a laminated structure including a lower layer 913a and an upper layer 913b formed on the lower layer 913a. A second contact hole CH2 exposing a portion of the first conductive layer 912 is formed in the gate insulating layer 4, and the second conductive layer 913 is connected to the first conductive layer 912 at the second contact hole CH2.

[0068] The third conductive layer 914 covers the second conductive layer 913 and is made of a transparent conductive material. The fourth conductive layer 915 is formed in the same layer as the first transparent electrode TE1. A third contact hole CH3 exposing a portion of the third conductive layer 914 is formed in the interlayer insulating layer 8, and the fourth conductive layer 915 is connected to the third conductive layer 914 through the third contact hole CH3. The first conductive layer 912, the second conductive layer 913, the third conductive layer 914, and the fourth conductive layer 915 are electrically connected to one another.

[0069] In the comparative example TFT substrate 910 having the above-described structure, the terminal portion 910Ta may be damaged by an etchant (for example, a PAN-based etching solution containing phosphoric acid, nitric acid, and acetic acid) used when forming the reflective electrode RE. The damage to the terminal portion 910Ta is presumed to be due to the following reasons.

[0070] 5, in the terminal portion 910Ta of the TFT substrate 910 of the comparative example, the second conductive layer 913 has a steeply tapered portion 913t that reflects the shape of the second contact hole CH2. As a result, cracks CL occur in the portions of the third conductive layer 914 and the fourth conductive layer 915 made of a transparent conductive material that are located on the tapered portion 913t, and the etchant that penetrates through the cracks CL damages the upper layer 913b (e.g., the Cu layer) of the second conductive layer 913.

[0071] In contrast, in the liquid crystal display device 100 of this embodiment, the lower conductive layer 12, which may be made of a metal material, is covered with the intermediate conductive layer 13, which is made of a transparent conductive material. Since there is little risk of cracks occurring in the intermediate conductive layer 13, which does not include a portion located on the steeply tapered portion, the lower conductive layer 12 is protected by the intermediate conductive layer 13 from the etchant used to form the reflective electrode RE. Therefore, damage to the terminal portion Ta is suppressed.

[0072] In the illustrated configuration, the first transparent electrode TE1 is disposed below the reflective electrode RE, and the second transparent electrode TE2 is disposed above the reflective electrode RE. By disposing the first transparent electrode TE1 below the reflective electrode RE, it is possible to improve the adhesion of the reflective electrode RE to the organic insulating layer 9. Furthermore, by disposing the second transparent electrode TE2 above the reflective electrode RE, it is possible to suppress oxidation of the reflective electrode RE, and it is possible to prevent degradation of display performance due to oxidation of the reflective electrode RE.

[0073] [Method of manufacturing the liquid crystal display device 100] The following describes a method for manufacturing the liquid crystal display device 100. First, the steps for manufacturing the TFT substrate 10 will be described with reference to Figures 6A to 6H and 7A to 7H.

[0074] 6A to 6H and 7A to 7H are cross-sectional views illustrating steps for fabricating the TFT substrate 10. Fig. 6A to 6H show a region where the TFT 2 is formed (TFT forming region), and Fig. 7A to 7H show a region where the terminal portion Ta is formed (terminal portion forming region).

[0075] STEP 1: Formation of gate metal layer (Figure 6A, Figure 7A) First, a gate conductive film (thickness: for example, 50 nm to 600 nm) is deposited on the substrate 1. The gate conductive film is deposited by, for example, sputtering. Next, the gate conductive film is patterned by a photolithography process. As a result, as shown in FIGS. 6A and 7A, the gate electrode 3, gate wiring GL, and lower conductive layer (first conductive layer) 12 are formed. The gate electrode 3, gate wiring GL, and lower conductive layer 12 are sometimes collectively referred to as the "gate metal layer."

[0076] An insulating substrate can be used as the substrate 1. Specifically, the substrate 1 can be a glass substrate, a silicon substrate, a heat-resistant plastic substrate (resin substrate), or the like.

[0077] The gate conductive film may be a metal film containing an element selected from aluminum (Al), chromium (Cr), copper (Cu), tantalum (Ta), titanium (Ti), molybdenum (Mo), or tungsten (W), or an alloy film containing these elements. Alternatively, a laminated film containing a plurality of these films may be used.

[0078] STEP 2: Formation of protective conductive layer 11 etc. (FIGS. 6B and 7B) Next, a transparent conductive film (thickness: for example, 20 nm to 300 nm) is formed so as to cover the gate metal layer. The transparent conductive film is formed, for example, by sputtering. The transparent conductive film may be made of, for example, ITO. The transparent conductive film is then patterned by a photolithography process. As a result, a protective conductive layer 11 and an intermediate conductive layer 13 are formed, as shown in FIGS. 6B and 7B.

[0079] STEP 3: Formation of gate insulating layer 4 and deposition of semiconductor film 5' (FIGS. 6C and 7C) Next, as shown in Figures 6C and 7C, a gate insulating layer 4 (thickness: for example, 200 nm or more and 600 nm or less) is formed to cover the protective conductive layer 11 and the intermediate conductive layer 13, and then a semiconductor film 5' is deposited on the gate insulating layer 4.

[0080] The gate insulating layer 4 is formed by, for example, a CVD method. As the gate insulating layer 4, for example, a silicon nitride (SiNx) layer can be used.

[0081] The semiconductor film 5' is an amorphous silicon film deposited by, for example, CVD. The thickness of the intrinsic semiconductor layer is, for example, 50 nm to 200 nm, and the thickness of the doped semiconductor layer is, for example, about 40 nm.

[0082] STEP 4: Formation of source metal layer and patterning of semiconductor film 5' (FIGS. 6D and 7D) Next, a source conductive film (thickness: for example, 50 nm to 500 nm) is deposited on the semiconductor film 5'. The source conductive film is deposited by, for example, sputtering. Next, the semiconductor film 5' and the source conductive film are patterned by a photolithography process using a multi-tone photomask. As a result, an island-shaped semiconductor layer 5, source electrode 6, drain electrode 7, and source wiring SL are formed, as shown in Figures 6D and 7D. The source electrode 6, drain electrode 7, and source wiring SL are collectively referred to as a "source metal layer."

[0083] Specifically, gray-tone masks and half-tone masks can be used as multi-tone photomasks. Gray-tone masks have slits formed in them that are smaller than the resolution of the exposure machine, and intermediate exposure is achieved by blocking part of the light through these slits. On the other hand, half-tone masks use a semi-transparent film to achieve intermediate exposure.

[0084] The source conductive film can be, for example, a metal film containing an element selected from aluminum (Al), chromium (Cr), copper (Cu), tantalum (Ta), titanium (Ti), molybdenum (Mo), or tungsten (W), or an alloy film containing these elements. A laminated film containing multiple films from these may also be used. In this example, the source conductive film is formed with a Ti film as the lower layer and a Cu film as the upper layer. In this way, TFT2 is completed.

[0085] STEP 5: Formation of interlayer insulating layer 8 and organic insulating layer 9 (FIGS. 6E and 7E) Next, as shown in FIGS. 6E and 7E, an interlayer insulating layer 8 (thickness: for example, 100 nm or more and 500 nm or less) is formed to cover the TFT 2, and then an organic insulating layer 9 (thickness: for example, 1 to 3 μm) is formed on the interlayer insulating layer 8.

[0086] The interlayer insulating layer 8 is formed by, for example, a CVD method. A silicon oxide (SiOx) layer, a silicon nitride (SiNx) layer, or the like can be appropriately used as the interlayer insulating layer 8. The interlayer insulating layer 8 may be a single layer or may have a multilayer structure.

[0087] The organic insulating layer 9 is made of, for example, a photosensitive resin material, such as an acrylic resin material.

[0088] An uneven surface structure is formed on the surface of the organic insulating layer 9 in the reflective region. An opening 9a is formed in the organic insulating layer 9, which overlaps with part of the drain electrode 7 when viewed from the normal direction of the substrate 1. Furthermore, the organic insulating layer 9 is not formed in the terminal portion forming region.

[0089] The process of forming the organic insulating layer 9 includes, for example, a process of applying a photosensitive resin material onto the interlayer insulating layer 8, a process of pattern-exposing the applied photosensitive resin material using a multi-tone photomask, a process of developing the pattern-exposed photosensitive resin material, and a process of baking after development.

[0090] STEP 6: Formation of openings 4a, 8a, and 8b in the gate insulating layer 4 and the interlayer insulating layer 8 (FIGS. 6F and 7F) 6F and 7F, openings 4a, 8a, and 8b are formed by a photolithography process in the gate insulating layer 4 and the interlayer insulating layer 8. Specifically, in the TFT formation region, opening 8a is formed in the interlayer insulating layer 8 to expose a portion of the drain electrode 7, and openings 4a and 8b are formed in the gate insulating layer 4 and the interlayer insulating layer 8 to expose a portion of the intermediate conductive layer 13 in the terminal portion formation region.

[0091] STEP 7: Formation of first transparent electrode TE1 etc. (Fig. 6G, Fig. 7G) Thereafter, a transparent conductive film (thickness: for example, 20 nm to 300 nm) is formed on the organic insulating layer 9. The transparent conductive film is formed, for example, by sputtering. The transparent conductive film may be made of, for example, ITO. Next, the transparent conductive film is patterned by a photolithography process. As a result, a first transparent electrode TE1 and an upper conductive layer 14 are formed on the organic insulating layer 9, as shown in FIGS. 6G and 7G.

[0092] STEP 8: Formation of the reflective electrode RE and the second transparent electrode TE2 (FIG. 6H, FIG. 7H) Next, a conductive film (thickness: for example, 50 nm to 300 nm) and a transparent conductive film (thickness: for example, 20 nm to 300 nm) are successively formed on the first transparent electrode TE1 and the organic insulating layer 9. These conductive film and transparent conductive film are formed, for example, by sputtering. Next, the conductive film and transparent conductive film are patterned by a photolithography process. As a result, as shown in FIG. 6H, a reflective electrode RE and a second transparent electrode TE2 are formed on a portion of the first transparent electrode TE1 located within the reflective region. The conductive film for forming the reflective electrode RE is, for example, an Al film, an Al alloy film, an Ag film, or an Ag alloy film. The transparent conductive film for forming the second transparent electrode TE2 can be made of, for example, ITO.

[0093] In this way, the TFT substrate 10 is produced. The process of producing the counter substrate 20 and the process of forming the liquid crystal layer 30 can be performed using various known techniques, and therefore, the description thereof will be omitted here.

[0094] According to the above-described manufacturing method, the semiconductor film 5′ and the source conductive film are simultaneously patterned by a photolithography process using a multi-tone photomask, thereby reducing the number of masks. Furthermore, in the step of forming the organic insulating layer 9, pattern exposure using a multi-tone photomask also reduces the number of masks. In the illustrated manufacturing method, the TFT substrate 10 can be manufactured using eight photomasks.

[0095] [Another liquid crystal display device 100A] Another liquid crystal display device 100A according to an embodiment of the present invention will be described with reference to Figures 8A and 8B. Figure 8A is a cross-sectional view schematically showing the liquid crystal display device 100A, illustrating a region corresponding to one pixel P. Figure 8B is a cross-sectional view schematically showing a terminal portion TaA of the TFT substrate 10 of the liquid crystal display device 100A. The following description will focus on the differences between the liquid crystal display device 100A and the liquid crystal display device 100 already described.

[0096] The structure of each pixel P of the liquid crystal display device 100A is substantially the same as the structure of each pixel P of the liquid crystal display device 100. However, as shown in FIG. 8A , the TFT 2A of the TFT substrate 10 of the liquid crystal display device 100A does not have a protective conductive layer covering the gate electrode 3.

[0097] The TFT substrate 10 of the liquid crystal display device 100A has a plurality of terminal portions TaA arranged in the non-display region FR. As shown in FIG. 8B, each terminal portion TaA includes a lower conductive layer (first conductive layer) 15, an intermediate conductive layer (second conductive layer) 16, and an upper conductive layer (third conductive layer) 17.

[0098] The lower conductive layer 15 is formed in the same layer as the source electrode 6 and the drain electrode 7 (i.e., made of the same conductive film as the source electrode 6 and the drain electrode 7). In the example shown, the lower conductive layer 15 has a laminated structure including a lower layer 15a and an upper layer 15b formed on the lower layer 15a. The intermediate conductive layer 16 is made of a transparent conductive material and covers the lower conductive layer 15.

[0099] Upper conductive layer 17 is formed in the same layer as first transparent electrode TE1 (i.e., made of the same conductive film as first transparent electrode TE1). A second contact hole CH2 exposing a portion of intermediate conductive layer 16 is formed in interlayer insulating layer 8, and upper conductive layer 17 is connected to intermediate conductive layer 16 at second contact hole CH2. Therefore, lower conductive layer 15, intermediate conductive layer 16, and upper conductive layer 17 are electrically connected to one another.

[0100] The terminal portion TaA further includes an underlying semiconductor layer 18 located below the lower conductive layer 15. The underlying semiconductor layer 18 is formed in the same layer as the semiconductor layer 5 (that is, from the same semiconductor film as the semiconductor layer 5).

[0101] The terminal portion TaA does not include a conductive layer formed in the same layer as the gate electrode 3. In other words, the terminal portion TaA does not include a conductive layer formed from the same conductive film as the gate electrode 3.

[0102] In the liquid crystal display device 100A having the above-described structure, the lower conductive layer 15, which may be made of a metal material, is covered with the intermediate conductive layer 16, which is made of a transparent conductive material. Since there is little risk of cracks occurring in the intermediate conductive layer 16 that does not include a portion located on the steeply tapered portion, the lower conductive layer 15 is protected by the intermediate conductive layer 16 from the etchant used to form the reflective electrode RE. Therefore, damage to the terminal portion TaA is suppressed in the liquid crystal display device 100A as well.

[0103] [Method of manufacturing the liquid crystal display device 100A] A method for manufacturing the liquid crystal display device 100A will be described below. First, the steps for manufacturing the TFT substrate 10 will be described with reference to Figures 9A to 9H and 10A to 10H.

[0104] 9A to 9H and 10A to 10H are cross-sectional views illustrating steps for fabricating the TFT substrate 10 of the liquid crystal display device 100A. 9A to 9H show a region where the TFT 2A is formed (TFT formation region), and 10A to 10H show a region where the terminal portion TaA is formed (terminal portion formation region).

[0105] STEP 1: Formation of gate metal layer (Figure 9A, Figure 10A) First, a gate conductive film (thickness: for example, 50 nm to 600 nm) is deposited on the substrate 1. The gate conductive film is deposited by, for example, sputtering. Next, the gate conductive film is patterned by a photolithography process. As a result, the gate electrode 3 and gate wiring GL are formed, as shown in FIG. 9A. The gate electrode 3 and gate wiring GL are collectively referred to as the "gate metal layer."

[0106] An insulating substrate can be used as the substrate 1. Specifically, the substrate 1 can be a glass substrate, a silicon substrate, a heat-resistant plastic substrate (resin substrate), or the like.

[0107] The gate conductive film may be a metal film containing an element selected from aluminum (Al), chromium (Cr), copper (Cu), tantalum (Ta), titanium (Ti), molybdenum (Mo), or tungsten (W), or an alloy film containing these elements. Alternatively, a laminated film containing a plurality of these films may be used.

[0108] STEP 2: Formation of gate insulating layer 4 and deposition of semiconductor film 5' (FIGS. 9B and 10B) Next, as shown in FIGS. 9B and 10B, a gate insulating layer 4 (thickness: for example, 200 nm to 600 nm) is formed to cover the gate metal layer, and then a semiconductor film 5′ is deposited on the gate insulating layer 4.

[0109] The gate insulating layer 4 is formed by, for example, a CVD method. As the gate insulating layer 4, for example, a silicon nitride (SiNx) layer can be used.

[0110] The semiconductor film 5' is an amorphous silicon film deposited by, for example, CVD. The thickness of the intrinsic semiconductor layer is, for example, 50 nm to 200 nm, and the thickness of the doped semiconductor layer is, for example, about 40 nm.

[0111] STEP 3: Formation of source metal layer and patterning of semiconductor film 5' (FIG. 9C, FIG. 10C) Next, a source conductive film (thickness: for example, 50 nm to 500 nm) is deposited on the semiconductor film 5'. The source conductive film is deposited by, for example, sputtering. Next, the semiconductor film 5' and the source conductive film are patterned by a photolithography process using a multi-tone photomask. As a result, as shown in Figures 9C and 10C, an island-shaped semiconductor layer 5, an underlying semiconductor layer 18, a source electrode 6, a drain electrode 7, a source wiring SL, and a lower conductive layer 15 are formed. The source electrode 6, the drain electrode 7, the source wiring SL, and the lower conductive layer 15 are collectively referred to as a "source metal layer."

[0112] The source conductive film can be, for example, a metal film containing an element selected from aluminum (Al), chromium (Cr), copper (Cu), tantalum (Ta), titanium (Ti), molybdenum (Mo), or tungsten (W), or an alloy film containing these elements. A laminated film containing multiple films from these may also be used. In this example, the source conductive film is formed with a Ti film as the lower layer and a Cu film as the upper layer. In this way, TFT2A is completed.

[0113] STEP 4: Formation of intermediate conductive layer (Figure 9D, Figure 10D) Next, a transparent conductive film (thickness: for example, 20 nm to 300 nm) is formed so as to cover the source metal layer. The transparent conductive film is formed, for example, by a sputtering method. The transparent conductive film may be made of, for example, ITO. Thereafter, the transparent conductive film is patterned by a photolithography process. As a result, an intermediate conductive layer 16 is formed, as shown in FIG. 10D.

[0114] STEP 5: Formation of interlayer insulating layer 8 and organic insulating layer 9 (FIG. 9E, FIG. 10E) Next, as shown in FIGS. 9E and 10E, an interlayer insulating layer 8 (thickness: for example, 100 nm or more and 500 nm or less) is formed to cover the TFT 2A, and then an organic insulating layer 9 (thickness: for example, 1 to 3 μm) is formed on the interlayer insulating layer 8.

[0115] The interlayer insulating layer 8 is formed by, for example, a CVD method. A silicon oxide (SiOx) layer, a silicon nitride (SiNx) layer, or the like can be appropriately used as the interlayer insulating layer 8. The interlayer insulating layer 8 may be a single layer or may have a multilayer structure.

[0116] The organic insulating layer 9 is made of, for example, a photosensitive resin material, such as an acrylic resin material.

[0117] An uneven surface structure is formed on the surface of the organic insulating layer 9 in the reflective region. An opening 9a is formed in the organic insulating layer 9, which overlaps with part of the drain electrode 7 when viewed from the normal direction of the substrate 1. Furthermore, the organic insulating layer 9 is not formed in the terminal portion forming region.

[0118] The process of forming the organic insulating layer 9 includes, for example, a process of applying a photosensitive resin material onto the interlayer insulating layer 8, a process of pattern-exposing the applied photosensitive resin material using a multi-tone photomask, a process of developing the pattern-exposed photosensitive resin material, and a process of baking after development.

[0119] STEP 6: Formation of openings 8a and 8b in interlayer insulating layer 8 (FIGS. 9F and 10F) 9F and 10F, openings 8a and 8b are formed by a photolithography process in the interlayer insulating layer 8. Specifically, in the TFT formation region, opening 8a is formed in the interlayer insulating layer 8 to expose a portion of the drain electrode 7, and opening 8b is formed in the interlayer insulating layer 8 to expose a portion of the intermediate conductive layer 16 in the terminal portion formation region.

[0120] STEP 7: Formation of first transparent electrode TE1 etc. (FIG. 9G, FIG. 10G) Thereafter, a transparent conductive film (thickness: for example, 20 nm to 300 nm) is formed on the organic insulating layer 9. The transparent conductive film is formed, for example, by sputtering. The transparent conductive film may be made of, for example, ITO. Next, the transparent conductive film is patterned by a photolithography process. As a result, a first transparent electrode TE1 and an upper conductive layer 17 are formed on the organic insulating layer 9, as shown in FIGS. 9G and 10G.

[0121] STEP 8: Formation of the reflective electrode RE and the second transparent electrode TE2 (FIG. 9H, FIG. 10H) Next, a conductive film (thickness: for example, 50 nm to 300 nm) and a transparent conductive film (thickness: for example, 20 nm to 300 nm) are successively formed on the first transparent electrode TE1 and the organic insulating layer 9. These conductive film and transparent conductive film are formed, for example, by sputtering. Next, the conductive film and transparent conductive film are patterned by a photolithography process. As a result, as shown in FIG. 9H, a reflective electrode RE and a second transparent electrode TE2 are formed on a portion of the first transparent electrode TE1 located within the reflective region. The conductive film for forming the reflective electrode RE is, for example, an Al film, an Al alloy film, an Ag film, or an Ag alloy film. The transparent conductive film for forming the second transparent electrode TE2 can be made of, for example, ITO.

[0122] In this way, the TFT substrate 10 is produced. The process of producing the counter substrate 20 and the process of forming the liquid crystal layer 30 can be performed using various known techniques, and therefore, the description thereof will be omitted here.

[0123] According to the above-described manufacturing method, the semiconductor film 5′ and the source conductive film are simultaneously patterned by a photolithography process using a multi-tone photomask, thereby reducing the number of masks. Furthermore, in the step of forming the organic insulating layer 9, pattern exposure using a multi-tone photomask also reduces the number of masks. In the illustrated manufacturing method, the TFT substrate 10 can be manufactured using eight photomasks.

[0124] Although the above description has been given of a reflective liquid crystal display device, the liquid crystal display device according to the embodiment of the present invention is not limited to the reflective type. The liquid crystal display device according to the embodiment of the present invention may be a transflective type (semi-transmissive type). In a transflective liquid crystal display device, each pixel P includes, in addition to a reflective region, a transmissive region that performs display in a transmissive mode using light emitted from a backlight (illumination device). [Industrial Applicability]

[0125] According to the embodiment of the present invention, in a liquid crystal display device in which each pixel includes a reflective region, damage to the terminal portion caused by an etchant used to form a reflective electrode can be suppressed. [Explanation of symbols]

[0126] 1 board 2. 2A thin film transistor (TFT) 3. Gate electrode 4 Gate insulating layer 5 Semiconductor layer 5c Channel region 5s Source Area 5d Drain region 6 Source electrode 6a Lower layer of source electrode 6b Top layer of source electrode 7. Drain electrode 7a Lower layer of drain electrode 7b Upper layer of drain electrode 8 Interlayer insulation layer 9 Organic insulating layer 10 TFT substrate 11 Protective conductive layer 12 Lower conductive layer (first conductive layer) 13 Intermediate conductive layer (second conductive layer) 14 Upper conductive layer (third conductive layer) 15 Lower conductive layer (first conductive layer) 15a Lower layer of the lower conductive layer 15b Upper layer of lower conductive layer 16 Intermediate conductive layer (second conductive layer) 17 Upper conductive layer (third conductive layer) 18 Underlying semiconductor layer 20 Opposing substrate 21 PCB 30 Liquid crystal layer 100, 100A LCD display P pixel p Protrusion of reflective electrode DR display area FR hidden area GL gate wiring SL Source wiring PE pixel electrode TE1 1st transparent electrode TE2 2nd transparent electrode RE reflective electrode CE counter electrode CH1 1st contact hole CH2 2nd contact hole Ta, TaA terminals

Claims

1. a first substrate; a second substrate facing the first substrate; a liquid crystal layer provided between the first substrate and the second substrate; Equipped with A liquid crystal display device having a display area including a plurality of pixels arranged in a matrix including a plurality of rows and a plurality of columns, and a non-display area located around the display area, Each of the plurality of pixels includes a reflective area that displays in a reflective mode; The first substrate is a thin film transistor provided in each of the plurality of pixels; a transparent electrode electrically connected to the thin film transistor; a reflective electrode provided on a portion of the transparent electrode located within the reflective region; a terminal portion disposed in the non-display area; and The thin film transistor is a semiconductor layer including a channel region and a source region and a drain region located on either side of the channel region; a gate electrode facing the channel region via a gate insulating layer; a source electrode electrically connected to the source region of the semiconductor layer; a drain electrode electrically connected to the drain region of the semiconductor layer; and The terminal portion is a lower conductive layer formed in the same layer as the gate electrode; an intermediate conductive layer formed of a transparent conductive material and covering the lower conductive layer; an upper conductive layer formed in the same layer as the transparent electrode; and The liquid crystal display device does not include a conductive layer formed in the same layer as the source electrode and the drain electrode.

2. 2. The liquid crystal display device according to claim 1, wherein the thin film transistor further comprises a protective conductive layer formed in the same layer as the intermediate conductive layer and covering the gate electrode.

3. The first substrate is an interlayer insulating layer covering the thin film transistor; an organic insulating layer provided on the interlayer insulating layer; and the transparent electrode is provided on the organic insulating layer, a first contact hole exposing a portion of the drain electrode is formed in the interlayer insulating layer and the organic insulating layer; 3. The liquid crystal display device according to claim 1, wherein the transparent electrode is connected to the drain electrode through the first contact hole.

4. the gate electrode is disposed below the semiconductor layer, a second contact hole exposing a portion of the intermediate conductive layer is formed in the gate insulating layer and the interlayer insulating layer; 4. The liquid crystal display device according to claim 3, wherein the upper conductive layer is connected to the intermediate conductive layer through the second contact hole.

5. a portion of the organic insulating layer located in the reflective region has an uneven surface structure; 4. The liquid crystal display device according to claim 3, wherein the portion of the transparent electrode located in the reflective region and the reflective electrode each have a concave-convex surface structure that reflects the concave-convex surface structure of the organic insulating layer.

6. 3. The liquid crystal display device according to claim 1, wherein the first substrate has a further transparent electrode provided on the reflective electrode.

7. a first substrate; a second substrate facing the first substrate; a liquid crystal layer provided between the first substrate and the second substrate; Equipped with A liquid crystal display device having a display area including a plurality of pixels arranged in a matrix including a plurality of rows and a plurality of columns, and a non-display area located around the display area, Each of the plurality of pixels includes a reflective area that displays in a reflective mode; The first substrate is a thin film transistor provided in each of the plurality of pixels; a transparent electrode electrically connected to the thin film transistor; a reflective electrode provided on a portion of the transparent electrode located within the reflective region; a terminal portion disposed in the non-display area; and The thin film transistor is a semiconductor layer including a channel region and a source region and a drain region located on either side of the channel region; a gate electrode facing the channel region via a gate insulating layer; a source electrode electrically connected to the source region of the semiconductor layer; a drain electrode electrically connected to the drain region of the semiconductor layer; and The terminal portion is a lower conductive layer formed in the same layer as the source electrode and the drain electrode; an intermediate conductive layer formed of a transparent conductive material and covering the lower conductive layer; an upper conductive layer formed in the same layer as the transparent electrode; and The liquid crystal display device does not include a conductive layer formed in the same layer as the gate electrode.

8. 8. The liquid crystal display device according to claim 7, wherein the terminal portion includes an underlying semiconductor layer formed in the same layer as the semiconductor layer and located below the lower conductive layer.

9. The first substrate is an interlayer insulating layer covering the thin film transistor; an organic insulating layer provided on the interlayer insulating layer; and the transparent electrode is provided on the organic insulating layer, a first contact hole exposing a portion of the drain electrode is formed in the interlayer insulating layer and the organic insulating layer; 9. The liquid crystal display device according to claim 7, wherein the transparent electrode is connected to the drain electrode through the first contact hole.

10. a second contact hole is formed in the interlayer insulating layer to expose a portion of the intermediate conductive layer; 10. The liquid crystal display device according to claim 9, wherein the upper conductive layer is connected to the intermediate conductive layer through the second contact hole.

11. a portion of the organic insulating layer located in the reflective region has an uneven surface structure; The liquid crystal display device according to claim 9 , wherein the portion of the transparent electrode located in the reflective region and the reflective electrode each have a concave-convex surface structure that reflects the concave-convex surface structure of the organic insulating layer.

12. 9. The liquid crystal display device according to claim 7, wherein the first substrate has a further transparent electrode provided on the reflective electrode.

13. 2. A method for manufacturing a liquid crystal display device according to claim 1, The step of fabricating the first substrate includes: (a) forming the thin film transistor on a substrate; a step (b) of forming an interlayer insulating layer covering the thin film transistor; (c) forming an organic insulating layer on the interlayer insulating layer; (d) forming the transparent electrode on the organic insulating layer; (e) forming the reflective electrode on a portion of the transparent electrode located within the reflective region; It encompasses The step (a) of forming the thin film transistor comprises: (a1) depositing a semiconductor film on the gate insulating layer; a step (a2) of depositing a source conductive film on the semiconductor film; a step (a3) ​​of forming the semiconductor layer, the source electrode, and the drain electrode by patterning the semiconductor film and the source conductive film by a photolithography process using a multi-tone photomask; A method for manufacturing a liquid crystal display device, comprising:

14. the organic insulating layer has an opening overlapping a portion of the drain electrode, a portion of the organic insulating layer located in the reflective region has an uneven surface structure; The step (c) of forming the organic insulating layer comprises: a step (c1) of applying a photosensitive resin material onto the interlayer insulating layer; (c2) a step of pattern-exposing the applied photosensitive resin material using a multi-tone photomask; a step (c3) of developing the pattern-exposed photosensitive resin material; The method of claim 13, comprising:

15. the step (a) of forming the thin film transistor further includes the step (a4) of forming the gate electrode, In the step (a4) of forming the gate electrode, the lower conductive layer of the terminal portion is formed together with the gate electrode, The manufacturing method according to claim 13 or 14, wherein in the step (d) of forming the transparent electrode, the upper conductive layer of the terminal portion is formed together with the transparent electrode.

16. the step (a) of forming the thin film transistor further includes a step (a5) of forming a protective conductive layer covering the gate electrode; The manufacturing method according to claim 15 , wherein in the step (a5) of forming the protective conductive layer, the intermediate conductive layer of the terminal portion is formed together with the protective conductive layer.

17. A method for manufacturing a liquid crystal display device according to claim 7, The step of fabricating the first substrate includes: (a) forming the thin film transistor on a substrate; a step (b) of forming an interlayer insulating layer covering the thin film transistor; (c) forming an organic insulating layer on the interlayer insulating layer; (d) forming the transparent electrode on the organic insulating layer; (e) forming the reflective electrode on a portion of the transparent electrode located within the reflective region; It encompasses The step (a) of forming the thin film transistor comprises: (a1) depositing a semiconductor film on the gate insulating layer; a step (a2) of depositing a source conductive film on the semiconductor film; a step (a3) ​​of forming the semiconductor layer, the source electrode, and the drain electrode by patterning the semiconductor film and the source conductive film by a photolithography process using a multi-tone photomask; A method for manufacturing a liquid crystal display device, comprising:

18. the organic insulating layer has an opening overlapping a portion of the drain electrode, a portion of the organic insulating layer located in the reflective region has an uneven surface structure; The step (c) of forming the organic insulating layer comprises: a step (c1) of applying a photosensitive resin material onto the interlayer insulating layer; (c2) a step of pattern-exposing the applied photosensitive resin material using a multi-tone photomask; a step (c3) of developing the pattern-exposed photosensitive resin material; The method of claim 17, comprising:

19. In the step (a3) ​​of forming the semiconductor layer, the source electrode, and the drain electrode, the lower conductive layer of the terminal portion is formed together with the source electrode and the drain electrode, The manufacturing method according to claim 17 or 18, wherein in the step (d) of forming the transparent electrode, the upper conductive layer of the terminal portion is formed together with the transparent electrode.

20. The manufacturing method according to claim 19 , wherein in the step (a3) ​​of forming the semiconductor layer, the source electrode, and the drain electrode, an underlying semiconductor layer located below the underlying conductive layer in the terminal portion is also formed.

21. The manufacturing method according to claim 17 or 18, further comprising the step (f) of forming the intermediate conductive layer of the terminal portion after the step (a) of forming the thin film transistor.

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