JP2006106516A - Electro-optical device substrate, electro-optical device, manufacturing method thereof, and electronic apparatus - Google Patents

Abstract

Contact resistance between a chromium layer and an ITO layer, which are elements of an external connection wiring, is kept low.
An external connection wiring has a structure in which a first conductive layer made of chromium, a second conductive layer made of ITO or the like, and a third conductive layer made of ITO are laminated in this order. is doing. In the manufacturing process of the element substrate, the second conductive layer 32b is formed so as to cover the surface of the first conductive layer 32a after the first conductive layer is formed and before the annealing process is performed. For this reason, it is possible to prevent an oxide film from being formed on the surface of the first conductive layer 32a by the heat treatment. Therefore, the contact resistance between the chromium layer 32a and the ITO layer 32b which are elements of the external connection wiring is kept low. The resistance value to one end of the external connection wiring 35 electrically connected to the X or Y driver IC can be prevented from increasing, and the X and Y driver IC can be prevented from malfunctioning when the liquid crystal display device is driven. .
[Selection] Figure 9

Description

  The present invention relates to an electro-optical device suitable for use in displaying various information.

  Conventionally, various electro-optical devices such as a liquid crystal display device, an organic electroluminescence display device, a plasma display device, and a field emission display device are known. In a two-terminal element type active matrix as an example of an electro-optical device or a liquid crystal panel called TFD (Thin Film Diode), a scanning line is provided on one of two substrates facing each other, and a scanning line is provided on the other substrate. A signal line (data line) and a pixel electrode are formed, and liquid crystal is sealed between both substrates. The other substrate is provided with an element having non-linear current-voltage characteristics such as TFD (thin film diode), and the element is connected to the pixel electrode and the signal line, respectively.

  In such a liquid crystal panel, a driving IC (driver IC) for driving a signal line and a scanning line on the other substrate called a so-called overhang region is a method such as COG (Chip On Glass) technology. Implemented by. This driving IC is electrically connected to a connection terminal such as an FPC (Flexible Printed Circuit) via an external connection wiring in which a chromium layer and an ITO (Indium-Tin Oxide) layer are laminated in this order, for example. It is connected. Thereby, for example, signals and power are supplied from the electronic device such as a mobile phone or an information terminal to the data line and the scanning line via the FPC and the driving IC.

  In the process of manufacturing the above-mentioned liquid crystal panel, usually, immediately after the wiring made of the chromium layer is formed, for example, heat treatment for adjusting the element characteristics of the nonlinear element is performed. An oxide film is formed on the surface of the wiring. For this reason, the contact resistance between the chromium layer and the ITO layer is increased, and the resistance of the external connection wiring is increased. As a result, the contact resistance from one end side of the external connection wiring connected to the driving IC to the other end side of the external connection wiring connected to the FPC increases, and the driving IC is driven when the liquid crystal panel is driven. There was a problem of malfunction.

  In addition, an electro-optical device having excellent operating characteristics is known by using a wiring in which an ITO film and a Cr film having higher conductivity than the ITO film are used for connection between the driving IC and the wiring substrate ( For example, see Patent Document 1). In addition, a relatively dense first transparent electrode layer and a second transparent electrode having a relatively rough surface formed above the first transparent electrode layer are connected to the driving IC and the wiring electrode. A liquid crystal display panel having stable electrical and mechanical connection by using a wiring electrode having a layer is known (see, for example, Patent Document 2).

JP 2002-303879 A Japanese Patent Laid-Open No. 6-160881

  The present invention has been made in view of the above points, and improves the contact resistance between the chromium layer, which is an element of the external connection wiring, and the ITO layer, etc., and is used for the external connection connected to the driving IC. Electricity capable of preventing a resistance value from increasing from one end side of the wiring to the other end side of the external connection wiring connected to the FPC and preventing the driving IC from malfunctioning during driving. It is an object to provide a substrate for an optical device, an electro-optical device, a manufacturing method thereof, and an electronic apparatus.

  In one aspect of the present invention, a substrate for an electro-optical device having a substrate and a plurality of external connection terminals formed in an overhang region on the substrate and electrically connected to an external circuit, and a counter electrode having a scanning electrode In the electro-optical device in which an electro-optical material is sealed between a substrate and the plurality of external connection terminals, a first metal layer and a second conductive layer are stacked in this order, and the second conductive layer is formed of ITO. , Molybdenum, an alloy containing molybdenum as a main component, or a material having oxidation resistance.

  In the above electro-optical device, an electro-optical material is sealed between an electro-optical device substrate and a counter substrate having scanning electrodes. The substrate for an electro-optical device includes a substrate and a plurality of external connection terminals that are formed in a protruding region on the substrate and are electrically connected to an external circuit. The plurality of external connection terminals are laminated in the order of the first metal layer and the second conductive layer, and the second conductive layer is formed of ITO, molybdenum, an alloy containing molybdenum as a main component, or a material having an oxidation resistance. Being done.

  In the electro-optical device having such a configuration, in the manufacturing process, after forming the first metal layer made of chromium or the like, and for forming a heat treatment or an insulating layer for adjusting the element characteristics of the switching element. Before firing, a second conductive layer is formed so as to cover the surface of the first metal layer. For this reason, it is possible to prevent an oxide film from being formed on the surface of the first metal layer.

  In one aspect of the electro-optical device, a plurality of wirings formed on the substrate and having a plurality of terminal portions, and a switching element formed on the substrate and electrically connected to a part of the plurality of wirings And a pixel electrode formed on an insulating film covering the switching element and electrically connected to the switching element, the switching element including a layer made of the same material as the first metal layer, The external connection terminal includes a third conductive layer that is laminated on the second conductive layer and is formed of ITO, molybdenum, an alloy containing molybdenum as a main component, or a material having an oxidation resistance.

  According to this aspect, the plurality of wirings are formed on the substrate. A switching element such as a TFD or a TFT is formed on a substrate and is electrically connected to a part of a plurality of wirings. The pixel electrode is electrically connected to the switching element. As a result, signals and power can be output from a plurality of wirings, for example, data lines and scanning lines, to the pixel electrodes via the switching elements. In a preferred example, the switching element may comprise a layer made of the same material as the first metal layer. In addition, the external connection terminal may include a third conductive layer that is stacked on the second conductive layer and is formed of ITO, molybdenum, an alloy containing molybdenum as a main component, or a material having an oxidation resistance.

  In another aspect of the above electro-optical device, the driving IC is provided on the substrate, and the external connection terminal is formed continuously with the plurality of wirings, and is provided with the terminal provided in the driving IC. A connecting portion.

  According to this aspect, the driving IC (driver IC) is provided on the substrate. The external connection terminal can be formed continuously with a plurality of wirings and includes a portion connected to a terminal (bump) provided in the driving IC. Therefore, for example, when a signal and power are supplied from an electronic device such as a mobile phone to the external circuit side, the signal and the like can be supplied to the driving IC and further supplied to a plurality of wirings through the driving IC. In a preferred example, the resistance value from one end side of the external connection terminal electrically connected to the driving IC (driver IC) to the other end side of the external connection terminal electrically connected to the external circuit is substantially reduced. It can be set to 100Ω or less. Accordingly, it is possible to prevent the drive IC (Y driver IC) from malfunctioning when the electro-optical device is driven. The external connection terminal on the substrate side and the input side terminal of the driving IC need not be formed continuously.

  In another aspect of the electro-optical device, the plurality of wirings are formed on the substrate corresponding to a frame region, and a plurality of terminal portions are formed on one end side of the plurality of wirings. The plurality of terminal portions are laminated in the order of the first metal layer, the second conductive layer, and the third conductive layer.

  According to this aspect, the plurality of wirings are provided on the substrate corresponding to the frame region that does not contribute to the display. A plurality of terminal portions are formed on one end side of the plurality of wirings. Each of the plurality of external connection terminals and each terminal portion of the plurality of wirings is electrically connected to the driving IC. In addition, the other end sides of the plurality of external connection terminals are electrically connected to, for example, a plurality of wirings of an external circuit. Thereby, for example, when a signal and power are supplied from an electronic device such as a mobile phone to the external circuit side, the signal or the like is supplied to the driving IC, and further, the signal is supplied to the plurality of wiring sides through the driving IC. be able to. Each terminal portion of the plurality of wirings has a structure in which a first conductive layer, a second conductive layer, and a third conductive layer are stacked in this order. For this reason, it is possible to prevent an oxide film from being formed on the surface of the first metal layer constituting the terminal portions of the plurality of wirings in the manufacturing process of the electro-optical device. Therefore, it is possible to prevent the contact resistance between the plurality of wirings and the driving IC from increasing.

  In another aspect of the electro-optical device, the electro-optical device substrate and the counter substrate are bonded together via a seal member, and a plurality of terminal portions are further provided on the other end side of the plurality of wirings. The plurality of terminal portions are stacked in the order of the first metal layer, the second conductive layer, and the third conductive layer, and the third conductive layer is scanned by the conductive particles. Connected to the electrode.

  According to this aspect, the electro-optical device substrate and the counter substrate are bonded to each other via, for example, a frame-shaped seal member having a plurality of conductive particles (conducting members). A plurality of terminal portions are formed on the other end side of the plurality of wirings, and the plurality of terminal portions have a structure in which a first metal layer, a second conductive layer, and a third conductive layer are stacked in this order. Yes. The third conductive layer serving as an element of the plurality of terminal portions is electrically connected to the conductive particles in the seal member, and the conductive particles are electrically connected to the scanning line electrode of the counter substrate. ing. By adopting such a configuration, in the manufacturing process in the vicinity thereof, after the first metal layer serving as the element of the terminal portion of the plurality of wirings is formed and before the above heat treatment and firing are performed, the first A second conductive layer is formed to cover one metal layer. Thereby, it can prevent that an oxide film is formed on the surface of the 1st metal layer used as the element of the terminal part. Therefore, it is possible to prevent the contact resistance between the conductive particles arranged in the seal member and the terminal portions of the plurality of wirings from increasing, and as a result, the resistance value from the plurality of wirings to the scanning electrodes via the conductive particles. Can be prevented from becoming high.

  In another aspect of the electro-optical device, the contact hole formed in the insulating film includes a conductive layer made of the same material as the third conductive layer between the pixel electrode and the switching element. The pixel electrode and the switching element are electrically connected through the conductive layer.

  According to this aspect, in the contact hole formed in the insulating film, the conductive layer made of the same material as the third conductive layer is provided between the pixel electrode and the switching element. The pixel electrode and the switching element are electrically connected via the conductive layer. With this configuration, in the manufacturing process in the vicinity thereof, for example, the first metal film made of tantalum tungsten or the like / the insulating layer made of tantalum oxide or the like / the second metal film made of chromium or the like is used. After the two metal films are formed and before the above-described heat treatment or baking, the conductive layer is formed so as to cover the second metal film. Thereby, it is possible to prevent an oxide film from being formed on the surface of the second metal film of the switching element. This can prevent the contact resistance between the pixel electrode and the switching element from increasing.

  In addition, an electronic apparatus including the electro-optical device as a display unit can be configured.

  In another aspect of the present invention, in the electro-optical device substrate comprising: a substrate; and a plurality of external connection terminals formed in an overhang region on the substrate and electrically connected to an external circuit. The connection terminal is formed by laminating a first metal layer and a second conductive layer in this order, and the second conductive layer is formed of ITO, molybdenum, an alloy containing molybdenum as a main component, or a material having an oxidation resistance. .

  The substrate for an electro-optical device includes a plurality of external connection terminals that are formed on the substrate and an overhang region on the substrate and are electrically connected to an external circuit such as an FPC. In the electro-optical device substrate having such a configuration, in the manufacturing process, after the first metal layer made of chromium or the like is formed, a heat treatment or an insulating layer for adjusting the element characteristics of the switching element is formed. Before firing is performed, a second conductive layer is formed so as to cover the surface of the first metal layer. For this reason, it is possible to prevent an oxide film from being formed on the surface of the first metal layer.

  In another aspect of the present invention, a first conductive layer forming step of forming a plurality of wirings, switching elements, and first conductive layers of external connection terminals on a substrate, respectively, and the first conductive layer of the external connection terminals. After forming the layer, after the second conductive layer forming step of forming the first conductive film on the first conductive layer to form the second conductive layer, and the step of forming the second conductive layer, A heat treatment step of heat-treating the switching element; a step of forming an insulating film on the substrate, the plurality of wirings and the switching element; a step of forming a contact hole in the insulating film; and a step of forming a contact hole on the insulating film. And forming the pixel electrode and electrically connecting the pixel electrode and the switching element through the contact hole, and on the second conductive layer of the external connection terminal. Deposit second conductive layer A third conductive layer forming step of forming a third conductive layer Te, to form a electro-optical device substrate by a process comprising.

  In the electro-optical device manufacturing method, first, the first conductive layer forming step becomes a plurality of wirings such as data lines and scanning lines, switching elements such as TFD and TFT, and elements for external connection terminals on the substrate. A first conductive layer such as chromium is formed. In the next second conductive layer forming step, after forming the first conductive layer of the external connection terminal, a first metal film is formed on the first conductive layer to form a second conductive layer. In the next heat treatment step, after the step of forming the second conductive layer, the switching element is heat treated (corresponding to annealing B in an embodiment described later). In the next step, an insulating film is formed on the substrate, the plurality of wirings, and the switching element. In the next step, a contact hole (opening) is formed in the insulating film by a stepper or a batch exposure machine. In the next third conductive layer forming step, a pixel electrode is formed by forming a second conductive layer (corresponding to a second transparent conductive film in an embodiment described later, the same hereinafter) on the insulating film, and The pixel electrode and the switching element are electrically connected through the contact hole. In this step, the second conductive layer, such as ITO, molybdenum, an alloy containing molybdenum as a main component, or a material having oxidation resistance (a material that is difficult to be oxidized), which is an element of the external connection terminal, is formed on the second conductive layer. A metal film is formed to form a third conductive layer made of ITO or the like.

  In particular, in this method of manufacturing the electro-optical device, after forming the first conductive layer that becomes an element of the external connection wiring, and before the heat treatment step of heat-treating the switching element, the first element that becomes the element of the external connection terminal. On the conductive layer, a first metal film (corresponding to a first transparent conductive film in an embodiment described later) is formed to form a second conductive layer. For this reason, heat is not directly applied to the surface of the first conductive layer, which is an element of the external connection terminal, whereby the surface of the first conductive layer is oxidized, that is, an oxide film is formed. Can be prevented. Therefore, the contact resistance between the first conductive layer and the second conductive layer is kept low.

  In one aspect of the above-described electro-optical device manufacturing method, the second conductive layer is molybdenum or an alloy containing molybdenum as a main component, and at least between the heat treatment step and the third conductive layer formation step, A cleaning step of cleaning the second conductive layer by washing with water;

  According to this aspect, the second conductive layer can be made of molybdenum or an alloy containing molybdenum as a main component. In this case, an oxide film is formed on the surface of the second conductive layer made of molybdenum or an alloy containing molybdenum as a main component by the heat treatment step, but the cleaning step between the heat treatment step and the third conductive layer formation step is performed. The second conductive layer made of at least molybdenum or an alloy containing molybdenum as a main component is washed with water. Thereby, the oxide film formed on the surface of the second conductive layer made of molybdenum or an alloy containing molybdenum as a main component can be easily removed.

  According to another aspect of the method of manufacturing the electro-optical device, the first conductive layer is formed on the other end side of the plurality of wirings in the first conductive layer forming step, and the first conductive layer forming step and the first A second conductive layer is formed on the first conductive layer between the two conductive layer steps; a third conductive layer is formed on the second conductive layer in the third conductive layer formation step; and for the electro-optical device. Bonding the substrate and the counter substrate through a sealing member having a plurality of conductive particles, and electrically connecting the third conductive layer on the other end side of the plurality of wirings and the plurality of conductive particles. Have.

  According to this aspect, in the first conductive layer forming step, the first conductive layer made of chromium or the like is formed on the other end side of the plurality of wirings. Further, between the first conductive layer forming step and the second conductive layer step, on the first conductive layer, from ITO, molybdenum, an alloy containing molybdenum as a main component, or a material having an oxidation resistance (a material that is not easily oxidized). A second conductive layer is formed. Thereby, it is possible to prevent an oxide film from being formed on the surface of the first conductive layer which is an element on the other end side of the plurality of wirings.

Further, in the third conductive layer forming step, a third conductive layer is formed on the second conductive film, and the electro-optical device substrate and the counter substrate are bonded via a sealing member having a plurality of conductive particles (conductive members). And a step of electrically connecting the third conductive layer on the other end side of the plurality of wirings and the plurality of conductive particles. Thereby, according to the other aspect of the manufacturing method of said electro-optical apparatus which can prevent that the contact resistance between the electrically-conductive particle arrange | positioned in a sealing member and the terminal part of the some wiring becomes high, A first conductive layer is formed on one end side of the plurality of wirings in the first conductive layer forming step, and the first conductive layer is formed on the first conductive layer between the first conductive layer forming step and the second conductive layer forming step. Two conductive layers are formed, a third conductive layer is formed on the second conductive layer in the third conductive layer forming step, and the third conductive layer on the one end side of the plurality of wirings, the driving IC, Are electrically connected.

  According to this aspect, the first conductive layer made of chromium or the like is formed on one end side of the plurality of wirings (for example, data lines) in the first conductive layer forming step. Further, between the first conductive layer forming step and the second conductive layer forming step, on the first conductive layer, ITO, molybdenum, an alloy containing molybdenum as a main component, or a material having an oxidation resistance (a material that is not easily oxidized) A second conductive layer made of is formed. Thereby, it is possible to prevent an oxide film from being formed on the surface of the first conductive layer which is an element on one end side of the plurality of wirings. In the third conductive layer forming step, a third conductive layer made of ITO or the like is formed on the second conductive layer. Thus, one end side of the plurality of wirings is formed in a structure in which the first conductive layer, the second conductive layer, and the third conductive layer are stacked in this order. Further, this aspect includes a step of electrically connecting the third conductive layer serving as an element on one end side of the plurality of wirings and the driving IC (X driver IC). For this reason, it is possible to prevent the contact resistance between the plurality of wirings and the driving IC (X driver IC) from increasing.

  According to another aspect of the method of manufacturing the electro-optical device, the first conductive layer is formed on one end side of the plurality of wirings in the first conductive layer forming step, and the first conductive layer forming step and the first The second conductive layer is formed on the first conductive layer during the two conductive layer forming step, the third conductive layer is formed on the second conductive layer in the third conductive layer forming step, and the plurality of wirings A step of electrically connecting the third conductive layer on the one end side and the driving IC.

  According to this aspect, in the first conductive layer forming step, the first conductive layer made of chromium or the like is formed on one end side of the plurality of wirings (for example, scanning lines). Further, between the first conductive layer forming step and the second conductive layer forming step, on the first conductive layer, ITO, molybdenum, an alloy containing molybdenum as a main component, or a material having an oxidation resistance (a material that is not easily oxidized) A second conductive layer made of is formed. Thereby, it is possible to prevent an oxide film from being formed on the surface of the first conductive layer which is an element on one end side of the plurality of wirings. In the third conductive layer forming step, a third conductive layer made of ITO or the like is formed on the second conductive layer. Thus, one end side of the plurality of wirings is formed in a structure in which the first conductive layer, the second conductive layer, and the third conductive layer are stacked in this order. Further, in this aspect, there is a step of electrically connecting the third conductive layer serving as an element on one end side of the plurality of wirings and the driving IC (Y driver IC). For this reason, it is possible to prevent the contact resistance between the plurality of wirings and the driving IC (Y driver IC) from increasing.

  In another aspect of the method of manufacturing the electro-optical device, the first conductive layer is formed in the order of a first metal film, an insulating film, and a second metal film to form the switching element, and the first conductive layer is formed. A conductive layer formed simultaneously with the third conductive layer is formed on the second metal film between the layer forming step and the second conductive layer forming step. In the third conductive layer forming step, the pixel electrode and the second conductive layer are formed. Electrically connecting to the conductive layer through the contact hole.

  According to this aspect, in the first conductive layer forming step, the first metal film made of tantalum tungsten or the like, the insulating film made of tantalum oxide or the like, and the second metal film made of chrome or the like are formed in this order to form a switching element. . Further, between the first conductive layer forming step and the second conductive layer forming step, a conductive layer formed simultaneously with the third conductive made of ITO or the like is formed on the second metal film. Thereby, it is possible to prevent an oxide film from being formed on the surface of the second metal film. In the third conductive layer forming step, the pixel electrode and the conductive layer are electrically connected through the contact hole. This can prevent the contact resistance between the pixel electrode and the switching element from increasing.

  The best mode for carrying out the present invention will be described below with reference to the drawings. In the following embodiments, the present invention is applied to a liquid crystal display device as an example of an electro-optical device. In this embodiment, in the process of manufacturing the liquid crystal display device, the first transparent conductive film is formed on the chromium film after the chromium film is formed and before the heat treatment is performed. Thereby, in particular, the contact resistance between the chromium film and the ITO film, which are elements of the external connection wiring, is kept low, and from one end side of the external connection wiring connected to the driving IC (driver IC) to the FPC The contact resistance between the connected external connection lines and the other end side is prevented from increasing, and the driving IC (driver IC) is prevented from malfunctioning when the liquid crystal display device is driven.

[Configuration of liquid crystal display device]
First, the configuration of the liquid crystal display device according to the embodiment of the present invention will be described. FIG. 1 is a plan view schematically showing a schematic configuration of a liquid crystal display device 100 of the present invention. In FIG. 1, the configuration of electrodes and wirings of the liquid crystal display device 100 is mainly shown as a plan view. Here, the liquid crystal display device 100 of the present invention is an active matrix driving method using a TFD element, and is a transflective liquid crystal display device. FIG. 2 is a schematic cross-sectional view along the cutting line AA ′ in the liquid crystal display device 100 of FIG.

  First, the cross-sectional configuration of the liquid crystal display device 100 taken along the cutting line A-A ′ will be described with reference to FIG.

  In FIG. 2, the liquid crystal display device 100 includes an element substrate 91 and a color filter substrate 92 disposed so as to face the element substrate 91, with a frame-shaped sealing member 3 attached thereto, and liquid crystal is sealed inside. Thus, the liquid crystal layer 4 is formed. The frame-shaped seal member 3 is mixed with a conductive member 7 such as a plurality of metal particles.

  On the inner surface of the lower substrate 2, a scattering layer 9 having fine irregularities formed on the surface is formed. On the inner surface of the scattering layer 9, a reflective layer 5 having a predetermined thickness is formed for each sub-pixel region SG. Each reflective layer 5 is formed with a rectangular opening 20 (hereinafter also referred to as “transmission opening region”). Each reflective layer 5 can be formed of a thin film such as aluminum, an aluminum alloy, or a silver alloy. The opening 20 is formed so as to have an area of a predetermined ratio with respect to the total area of the sub-pixel region SG for each sub-pixel region SG arranged in a matrix in the vertical and horizontal directions on the inner surface of the color filter substrate 92. .

  In order to prevent light from entering from one subpixel to the other subpixel between the subpixel regions SG on the reflective layer 5 and between adjacent subpixel regions SG, a black light shielding layer A BM is formed. The black light shielding layer BM can be made of a black resin material, for example, a black pigment dispersed in a resin. In the present invention, instead of this, an overlapping light shielding layer (not shown) formed by overlapping R, G, and B colored layers may be used.

  On the reflective layer 5 and the opening 20, colored layers 6R, 6G, and 6B made of any of the three colors R, G, and B are formed for each sub-pixel region SG. A color filter is constituted by the colored layers 6R, 6G, and 6B. A pixel G indicates a region for one color pixel composed of R, G, and B sub-pixels. In the following description, when referring to a colored layer regardless of color, it is simply referred to as “colored layer 6”, and when referring to a colored layer by distinguishing colors, it is referred to as “colored layer 6R” or the like. Further, as shown in FIG. 2, the thickness of the colored layer 6 formed on the opening 20 is thicker than the thickness of the colored layer 6 formed on the reflective layer 5. Thus, the colored layer 6 is designed to exhibit a desired hue and brightness in the reflective display mode and the transmissive display mode, respectively.

  A protective layer 18 made of a transparent resin or the like is formed on the colored layer 6 and the black light shielding layer BM. The protective layer 18 has a function of protecting the colored layer 6 from corrosion and contamination caused by chemicals used during the manufacturing process of the color filter substrate 92. On the surface of the protective layer 18, a transparent electrode (scanning electrode) 8 such as striped ITO (Indium-Tin Oxide) is formed. One end of the transparent electrode 8 extends into the seal member 3 and is electrically connected to the conducting member 7 in the seal member 3.

On the other hand, a Ta ₂ O ₅ film 70 serving as a base layer is formed on the inner surface of the upper substrate 1. On the inner surface of the Ta ₂ O ₅ film 70, the data line 32 and the TFD element 21 are formed. On the inner surfaces of the Ta ₂ O ₅ film 70, the data line 32, and the TFD element 21, an insulating overlayer 25 is formed. On the inner surface of the overlayer 25, the pixel electrode 10 is formed for each sub-pixel region SG. Scanning lines 31 are formed on the left and right peripheral edge portions on the inner surface of the upper substrate 1, and terminal portions 31 ba of the scanning lines 31, that is, terminal portions 31 ba extend into the seal member 3. The conductive member 7 in the seal member 3 is electrically connected through the terminal portion 31ba.

  An alignment film (not shown) is formed on the inner surface of the transparent electrode 8 of the lower substrate 2 and the inner surface of the pixel electrode 10 of the upper substrate 1. In order to keep the thickness of the liquid crystal layer 4 uniform between these alignment films, particulate spacers (not shown) are randomly arranged. As a material for the spacer, a material mainly composed of silica or resin is preferable.

  A retardation plate (¼ wavelength plate) 11 and a polarizing plate 12 are arranged on the outer surface of the lower substrate 2, and a retardation plate (¼ wavelength plate) on the outer surface of the upper substrate 1. 13 and a polarizing plate 14 are arranged. A backlight 15 is disposed below the polarizing plate 12. The backlight 15 is preferably a point light source such as an LED (Light Emitting Diode) or a combination of a linear light source such as a cold cathode fluorescent tube and a light guide plate.

  The transparent electrode 8 of the lower substrate 2, that is, the scanning line of the lower substrate 2, and the scanning line 31 of the upper substrate 1 are vertically connected via the conductive member 7 mixed in the seal member 3.

  Now, when reflective display is performed in the liquid crystal display device 100 of the present embodiment, the external light incident on the liquid crystal display device 100 travels along the path R shown in FIG. That is, the external light incident on the liquid crystal display device 100 is reflected by the reflective layer 5 and reaches the observer. In this case, the external light passes through the region where the colored layer 6 is formed, is reflected by the reflective layer 5 below the colored layer 6, and passes through the colored layer 6 again to have a predetermined hue. And brightness. Thus, a desired color display image is visually recognized by the observer.

  On the other hand, when transmissive display is performed, the illumination light emitted from the backlight 15 travels along the path T shown in FIG. 2, and passes through the transmissive aperture region, that is, the colored layer 6 on the aperture 20 for observation. To the person. In this case, the illumination light has a predetermined hue and brightness by passing through the colored layer 6. Thus, a desired color display image is visually recognized by the observer.

  Next, with reference to FIG. 1, FIG. 3, and FIG. 4, the configuration of the electrodes and wirings of the element substrate 91 and the color filter substrate 92 of the present invention will be described. FIG. 3 is a plan view showing a configuration of electrodes, wirings, and the like of the element substrate 91 when the element substrate 91 is observed from the front direction (that is, the lower side in FIG. 2). FIG. 4 is a plan view showing the configuration of the electrodes of the color filter substrate 92 when the color filter substrate 92 is observed from the front direction (that is, the upper side in FIG. 2). In FIG. 3 and FIG. 4, other elements other than the electrodes and wiring are not shown for convenience of explanation.

  In FIG. 1, a region where the pixel electrode 10 of the element substrate 91 and the transparent electrode 8 of the color filter substrate 92 intersect constitute a sub-pixel that is the minimum unit of display. An area in which a plurality of sub-pixels are arranged in a matrix in the vertical direction and the horizontal direction of the drawing is an effective display area V (area surrounded by a two-dot chain line). In the effective display area V, images such as letters, numbers, and figures are displayed. 1 and 3, a region defined by the outer periphery of the liquid crystal display device 100 and the effective display region V is a frame region 38 that does not contribute to image display.

(Electrode and wiring configuration)
First, with reference to FIG. 3, the structure of the electrode and wiring of the element substrate 91 will be described. In FIG. 3, the direction from the side 91a on the projecting region 36 side of the element substrate 91 to the opposite side 91c is defined as the Y direction, and the direction from the side 91d toward the side 91b is defined as the X direction.

  The element substrate 91 includes a plurality of data lines 32, a TFD element 21, a pixel electrode 10, a plurality of scanning lines 31, a Y driver IC 33, an X driver IC 34, a plurality of external connection wirings 35, and an FPC 90.

  The plurality of data lines 32 are linear wirings extending in the Y direction, and are formed from the extended region 36 to the effective display region V. Each data line 32 is formed at a constant interval. Each data line 32 is connected to each TFD element 21 at an appropriate interval, and each TFD element 21 is connected to each corresponding pixel electrode 10. Thereby, each data line 32 is electrically connected to each pixel electrode 10 via each TFD element 21.

  The plurality of scanning lines 31 includes a main line portion 31a and a bent portion 31b that bends at substantially right angles to the main line portion 31a. Each main line portion 31 a is formed in the Y direction from the projecting region 36 in the frame region 38. Each main line portion 31a is formed substantially parallel to each data line 32 and at a predetermined interval. Each bent portion 31 b extends in the X direction to the inside of the seal member 3 located on the left and right in the frame region 38. The terminal portion 31ba of the bent portion 31b, that is, the terminal portion 31ba is electrically connected to the conducting member 7 in the seal member 3. The terminal portion 31ba of the bent portion 31b has a laminated structure that characterizes the present invention. This will be described later. Note that portions of the data line 32 and the scanning line 31 formed in the overhang region 36 and the frame region 38 are also referred to as lead wiring or simply wiring.

  On the projecting region 36 of the element substrate 91, a Y driver IC 33 and an X driver IC 34 are mounted. A plurality of external connection wires 35 are formed on the overhang region 36. The plurality of external connection wirings 35 have a laminated structure that characterizes the present invention, which will be described later.

  The Y driver IC 33 includes a plurality of conductive bumps 33b on the input side and a plurality of conductive bumps 33a on the output side. The input side of the Y driver IC 33 is electrically connected to one end side of the external connection wiring 35 via a plurality of bumps 33b and an ACF (Anisotropic Conductive Film) (not shown). On the other hand, the output side of the Y driver IC 33 is electrically connected to one end side of the plurality of scanning lines 31 via a plurality of bumps 33a and an ACF (not shown). Thereby, the Y driver IC 33 can output scanning signals to the plurality of scanning lines 31.

  The X driver IC 34 includes a plurality of conductive bumps 34b on the input side and a plurality of conductive bumps 34a on the output side. The input side of the X driver IC 34 is electrically connected to one end side of the external connection wiring 35 via a plurality of bumps 34b and an ACF (not shown). On the other hand, the output side of the X driver IC 34 is electrically connected to one end side of the plurality of data lines 32 via a plurality of bumps 34a and an ACF (not shown). As a result, the X driver IC 34 can output data signals to the plurality of data lines 32.

  The FPC 90 has a plurality of wirings 90a, and one end side of each wiring 90a is electrically connected to the other end side of the plurality of external connection wirings 35 via an ACF (not shown).

  In the element substrate 91 having the above-described electrode and wiring structure, a data signal is sent to the data line 32 from an electronic device such as a mobile phone or an information terminal via the FPC 90, each Y driver IC 33, the X driver IC 34, and the like. A scanning signal is output to each.

  Next, the configuration of the electrodes of the color filter substrate 92 will be described. As shown in FIG. 4, the color filter substrate 92 has stripe-shaped transparent electrodes (scanning electrodes) 8 formed in the X direction. As shown in FIGS. 1 and 4, the left end portion or the right end portion of each transparent electrode 8 extends into the seal member 3 and is electrically connected to the conduction member 7 in the seal member 3. Yes.

  FIG. 1 shows a state where the color filter substrate 92 and the element substrate 91 described above are bonded together via the seal member 3. As shown in the figure, each transparent electrode 8 of the color filter substrate 91 is orthogonal to each data line 32 of the element substrate 92 and overlaps the plurality of pixel electrodes 10 in a row in a plane. Thus, the region where the transparent electrode 8 and the pixel electrode 10 overlap constitutes the sub-pixel region SG.

  Further, the transparent electrode 8 of the color filter substrate 92 (that is, the scanning line on the color filter substrate 92 side) and the scanning line 31 of the element substrate 91 alternately overlap between the left side and the right side as shown in the figure. The transparent electrode 8 and the scanning line 31 are vertically connected via the conductive member 7 in the seal member 3. That is, conduction between each scanning line of the color filter substrate 92 as the transparent electrode 8 and each scanning line 31 of the element substrate 91 is alternately realized between the left side and the right side as shown in the figure. Thus, the transparent electrode 8 of the color filter substrate 92 is electrically connected to the Y driver ICs 33 located on the left and right sides of the paper via the scanning lines 31 of the element substrate 91.

(Overlayer structure)
Next, the structure of the element substrate 91 in the liquid crystal display device 100, that is, a so-called overlayer structure will be described with reference to FIGS. FIG. 5 is a plan view showing a layout of a plurality of pixel electrodes 10 and the like on the element substrate 91. FIG. 6 is a partial cross-sectional view taken along a cutting line BB ′ in FIG. 5 shows a configuration when the observation side is viewed from the back side, so that the near side in FIG. 5 is the back side and the upper side in FIG. 6 is the back side. FIG. 7 is a cross-sectional view corresponding to FIG. 6, and particularly shows another example of an element substrate in which the electrical configuration of the pixel electrode 10 and the TFD element 21 is slightly different from that of FIG. 6.

A phase difference plate 13 and a polarizing plate 14 are disposed on the outer surface of the upper substrate 1. On the other hand, a Ta ₂ O ₅ film 70 is formed on the inner surface of the upper substrate 1. On the inner surface of the Ta ₂ O ₅ film 70, the TFD element 21 and the data line 32 are formed.

The TFD element 21 includes a first TFD element 21a and a second TFD element 21b. The first TFD element 21a and the second TFD element 21b are made of an island-shaped first metal film 322 made of TaW (tantalum tungsten) containing tantalum as a main component, and the surface of the first metal film 322 is anodized. And an insulating film 323 made of Ta ₂ O ₅ or the like, and second metal films 316 and 336 formed on the surface and spaced apart from each other. Among these, the second metal films 316 and 336 are obtained by patterning the same conductive film such as chromium or molybdenum, and the former second metal film 316 is branched from the data line 32 in a T shape. On the other hand, the latter second metal film 336 is used for connection to a connection portion 10z of the pixel electrode 10 such as ITO described later.

  Here, among the TFD elements 21, the first TFD element 21 a becomes the second metal film 316 / insulating film 323 / first metal film 322 in order when viewed from the data line 32 side. Due to the body / metal structure, the current-voltage characteristics are nonlinear in both positive and negative directions. On the other hand, when viewed from the data line 32 side, the second TFD element 21b becomes a first metal film 322 / insulating film 323 / second metal film 336 in the order opposite to the first TFD element 21a. The structure of For this reason, the current-voltage characteristics of the second TFD element 21b are obtained by making the current-voltage characteristics of the first TFD element 21a point-symmetric with respect to the origin. As a result, the TFD element 21 has a shape in which two TFDs are connected in series in opposite directions. Therefore, the current-voltage nonlinear characteristic is symmetric in both positive and negative directions compared to the case of using one element. become.

An overlayer 25 is formed on the inner surface of the Ta ₂ O ₅ film 70, and the TFD element 21 and the data line 32 are covered with the overlayer 25. The overlayer 25 has an opening, that is, a contact hole 25a having a substantially trapezoidal shape in a cross-sectional view for each sub-pixel region SG. A pixel electrode 10 is formed on the inner surface of the overlayer 25 corresponding to the sub-pixel region SG.

  As shown in FIG. 5, the pixel electrodes 10 are arranged in a matrix on the inner surface of the overlayer 25. The pixel electrodes 10a, 10b, and 10c are opposed to the colored layers 6 corresponding to B (blue), R (red), and G (green) colors, respectively. Each pixel electrode 10 has a connection portion 10 z that extends into the contact hole 25 a and is electrically connected to the TFD element 21. The connection portion 10z of each pixel electrode 10 is connected to the second metal film 336 of the corresponding TFD element 21 through the contact hole 25a. The pixel electrodes 10 belonging to the same column are commonly connected to one data line 32 via the TFD elements 21. In addition, the pixel electrodes 10 belonging to the same row face one transparent electrode 8 (scanning line).

  In the element substrate 91 having the above configuration, in particular, the contact resistance between the connection portion 10z of the pixel electrode 10 and the second metal film 336 is set to be 1 MΩ or less.

  In the present invention, instead of the configuration of the element substrate 91 described above, as shown in FIG. 7, a conductive film 380 in which the connection portion 10z of the pixel electrode 10 and the second metal film 336 of the TFD element 21 are made of ITO or the like. You may make it the structure electrically connected through this.

  That is, in the element substrate 95 having this configuration, the conductive film 380 is formed on the second metal film 336 corresponding to the position of the contact hole 25a. The connection portion 10z of the pixel electrode 10 is electrically connected to the second metal film 336 via the conductive film 380. The conductive film 380 may be formed not only on the second metal film 336 but also around the periphery thereof. This is because the conductive film 380 has transparency, and the aperture ratio does not decrease even when the conductive film 380 overlaps the pixel electrode 10. However, as described below, in view of the object of the present invention, the conductive film 380 may be formed only on the second metal film 336 corresponding to the position of the contact hole 25a as described above.

That is, in the element substrate 95 having such a configuration, the conductive film 380 is formed on the second metal film 336 corresponding to the position of the contact hole 25a after the second metal film 336 is formed. Then, heat treatment for adjusting the element characteristics of the TFD element 21 is performed, and then baking for forming the overlayer 25 is performed. If the conductive film 380 is not formed on the second metal film 336 corresponding to the position of the contact hole 25a, the surface of the second metal film 336 is oxidized by such heat treatment or baking. That is, an oxide film is formed on the surface of the second metal film 336. When such an oxide film is formed, the contact resistance between the pixel electrode 10 and the second metal film 336 increases. However, in the configuration like the element substrate 95, the surface of the second metal film 336 corresponding to the position of the contact hole 25a is covered with the conductive film 380 before such heat treatment or baking is performed. Thereby, it is possible to prevent the contact resistance between the connection portion 10z of the pixel electrode 10 and the second metal film 336 from becoming higher than necessary. In view of such a purpose, the conductive film 380 is not limited to ITO, and the oxide film is formed by washing with water in a pre-process such as heat treatment even if a material that is not easily oxidized or an oxide film is formed. Molybdenum-based materials that can be easily removed may also be used.
(Configuration of external connection wiring, etc.)
Next, the configuration of the external connection wiring 35 and the like that characterize the present invention will be described with reference to FIGS. FIG. 8 shows a partially enlarged plan view in which the vicinity of the broken line area E2 in FIG. 3 is enlarged. FIG. 9 shows a partial cross-sectional view along the cutting line CC ′ in FIG.

A Ta ₂ O ₅ film 70 is formed on the lower substrate 1. A plurality of data lines 32 and external connection wirings 35 are formed on the Ta ₂ O ₅ film 70.

  Each data line 32 includes a main line 32y (corresponding to the region E21) formed of a material such as chromium and having a single layer structure, and a terminal portion 32x (corresponding to the region E20) having a multilayer structure on one end side of the main line 32y. have. The main line 32y extends from the side of the effective display area V (not shown) to the vicinity of the X driver IC 34. As shown in FIG. 9, the terminal portion 32x includes a first conductive layer 32a made of a conductive material such as chromium, a second conductive layer 32b made of a conductive material such as ITO, and a third conductive layer made of a conductive material such as ITO. The conductive layer 32c is stacked in this order. The first conductive layer 32a, the second conductive layer 32b, and the third conductive layer 32c are formed to have the same length and wiring width. In a preferred example, the thickness of the first conductive layer 32a can be about 3000 mm, the thickness of the second conductive layer 32b can be about 500 mm, and the thickness of the third conductive layer 32c can be about 500 mm. The third conductive layer 32 c that is an element of the terminal portion 32 x is electrically connected to each bump 34 a on the output side of the X driver IC 34 via the ACF 80. The ACF 80 is constituted by an adhesive resin material 80a and conductive particles 80b dispersed therein.

  The external connection wiring 35 has the same stacked structure as the terminal portion 32x. That is, the external connection wiring 35 includes a first conductive layer 35a made of a conductive material such as chromium, a second conductive layer 35b made of a conductive material such as ITO, and a third conductive layer 35c also made of a conductive material such as ITO. Are stacked in this order. The first conductive layer 35a, the second conductive layer 35b, and the third conductive layer 35c are formed to have the same length and wiring width, respectively. In a preferred example, the thickness of the first conductive layer 35a can be about 3000 mm, the thickness of the second conductive layer 35b can be about 500 mm, and the thickness of the third conductive layer 35c can be about 500 mm.

  One end side of the external connection wiring 35, specifically, one end side of the third conductive layer 35 c is electrically connected to each input side bump 34 b of the X driver IC 34 via the ACF 80. On the other hand, the other end side of the external connection wiring 35, specifically, the other end side of the third conductive layer 35 c is electrically connected to the plurality of wirings 90 a of the corresponding FPC 90 via the ACF 80. The average resistance value from the other end of the external connection wiring 35 electrically connected to the FPC 90 to one end of the external connection wiring 35 electrically connected to the X driver IC 34 is about 100Ω or less. Is set. With this wiring configuration, the signal and power from the FPC 90 side are output to the X driver IC 34 through the external connection wiring 35. The X driver IC 34 outputs a data signal to the data line 32 based on the output signal and the like.

  In the element substrate 91 described above, after the first conductive layer 35a and the first conductive layer 32a made of chromium or the like are formed in the manufacturing process, heat treatment or overheating for adjusting the element characteristics of the TFD element 21 is performed. Before firing for forming the layer 25, the second conductive layer 35b or the second conductive layer 32b is formed so as to cover the surfaces of the first conductive layer 35a and the first conductive layer 32a. For this reason, it can prevent that an oxide film is formed on the surface of the 1st conductive layer 35a and the 1st conductive layer 32a. Therefore, the contact resistance between the first conductive layer 35a and the first conductive layer 32a and the second conductive layer 35b or the second conductive layer 32b is kept low, and the external connection wiring electrically connected to the FPC 90 It is possible to prevent a resistance value from increasing from the other end side of 35 to one end side of the external connection wiring 35 electrically connected to the X driver IC 34. In a preferred example, an average resistance value from the other end side of the external connection wiring 35 electrically connected to the FPC 90 to one end side of the external connection wiring 35 electrically connected to the X driver IC 34 is about It can be set to be 100Ω or less. Thereby, it is possible to prevent the X driver IC 34 from malfunctioning when the liquid crystal display device 100 is driven.

  In the above description, the configuration of the external connection wiring 35 connected to each of the X driver IC 34 and the FPC 90 and the operation effect thereof have been described. Such a configuration and operational effect are similarly applied to the external connection wiring 35 connected to each of the Y driver ICs 33 and the FPC 90. As shown in FIGS. 1 and 3, the end portion of the bent portion 31 b of the scanning line 31, that is, the terminal portion 31 ba has a stacked structure similar to the terminal portion 32 x of the data line 32. That is, the terminal portion 31ba includes a first conductive layer (not shown) made of chromium or the like, a second conductive layer (not shown) made of ITO or the like, and a third conductive layer (not shown) also made of ITO or the like. , In this order. Therefore, as can be understood with reference to FIG. 2, the third conductive layer constituting the terminal portion 31 ba of the scanning line 31 is actually electrically connected to the conducting member 7 in the seal member 3. . By adopting such a configuration, in the manufacturing process in the vicinity thereof, the second conductive layer is formed so as to cover the first conductive layer after the first conductive layer is formed and before the above-described heat treatment or baking is performed. A layer is formed. For this reason, it is possible to prevent an oxide film from being formed on the surface of the first conductive layer, and it is possible to prevent the contact resistance between the conductive member 7 disposed in the seal member 3 and the terminal portion 31ba from increasing. As a result, the resistance value from the scanning line 31 to the transparent electrode 8 through the conductive member 7 can be prevented from increasing.

  In the external connection wiring 35 described above, the first conductive layer 35a, the second conductive layer 35b, and the third conductive layer 35c were formed to have the same length and wiring width. However, the present invention is not limited to this, and the length and the wiring width may be different from each other. For example, FIG. 10 shows an example. FIG. 10A is an enlarged partial plan view showing the vicinity of the broken line area E3 in FIG. 8, and is an enlarged partial plan view showing, in particular, the portion of the external connection wiring 35. FIG. FIG. 10B is a partial cross-sectional view taken along the cutting line D-D ′ in FIG. In FIG. 10, illustration of the FPC 90 and the X driver IC 34 is omitted for convenience.

  In the example shown in FIG. 10, the first conductive layer 35a has a larger outer shape than the second conductive layer 35b, and the third conductive layer 35c has a larger outer shape than the first conductive layer 35a. . That is, the outer shape of the first conductive layer 35a is formed to be larger than the outer shape of the second conductive layer 35b by the length D1. Here, the length D1 can be about 1 μm. Further, the outer shape of the third conductive layer 35c is formed to be larger by the length D2 than the outer shape of the first conductive layer 35a. Therefore, as shown in FIG. 10, the third conductive layer 35c completely covers the first conductive layer 35a and the second conductive layer 35b.

With such a configuration, in the process of forming the external connection wiring 35, the wiring 35 can be formed with high quality. That is, when forming the external connection wiring 35, first, the first conductive layer 35a is formed on the Ta ₂ O ₅ film 70, and then the second conductive layer 35b is formed on the first conductive layer 35a by photolithography. However, when the second conductive layer 35b is etched, the peripheral portion of the second conductive layer 35b may not be etched cleanly. As a result, the electrical performance of the external connection wiring 35 itself is not deteriorated, but there is a problem that the wiring 35 is not visually formed beautifully. However, even when the peripheral edge portion of the second conductive layer 35b is not completely etched in this way, the first conductive layer 35a as well as the second conductive layer 35b is completely covered by the above configuration. Thus, the third conductive layer 35c is formed. As a result, the external connection wiring 35 is formed in a visually clean state.

  In the above embodiment, the external connection wiring 35, the terminal portion 32x of the data line 32, the terminal portion (not shown) of the scanning line 31 corresponding to the terminal portion 32x, and the terminal portion of the bent portion 31b of the scanning line 31 The second conductive layer, which is a component of 31ba, was formed of ITO. However, the present invention is not limited to this, and in the present invention, the second conductive layer may be formed of a material that is not easily oxidized or a molybdenum-based material.

  In the above embodiment, the scanning line 31 and the data line 32 are made of chromium except for the terminal portion 31ba and the terminal portion 32x, respectively. However, the present invention is not limited to this, and in the present invention, the scanning line 31 corresponding to the distance between the Y driver IC 33 and the sealing member 3 and / or the data line 32 corresponding to the distance between the X driver IC 34 and the sealing member 3 are connected to the terminal. A stacked structure similar to the portions 31ba and 32x or a two-layer structure with the third conductive layer may be used.

[Method of manufacturing liquid crystal display device]
Next, a method for manufacturing the liquid crystal display device 100 will be described with reference to FIGS. 1, 11 to 21, and the like. FIG. 11 is a flowchart showing a method for manufacturing the liquid crystal display device 100. FIG. 12 is a flowchart corresponding to step S <b> 1 in FIG. 11, specifically a flowchart showing a method for manufacturing the element substrate 91. In particular, the present invention is characterized by the process P9 and the process P11 ′ in the flowchart of FIG. 13 to 21 correspond to each step of the flowchart of FIG. 13 to 21, a plan view corresponding to the manufacturing process of the portion shown in FIG. 6 or 7 and a cross-sectional view corresponding thereto are shown on the upper side of the drawing, and FIG. 9 is shown on the lower side of the drawing. Sectional drawing corresponding to the manufacturing process of the part shown is shown. In the following, please refer to FIG. 6, FIG. 7 or FIG. 9 as needed. In addition, since the manufacturing process in the vicinity of the Y driver IC 33 is substantially the same as the manufacturing process in the vicinity of the X driver IC 34, the configuration and description thereof are omitted in FIGS. Further, in the plan views of FIGS. 13 to 21, a rectangular broken line area indicates one sub-pixel area SG.

First, the element substrate 91 is manufactured (step S1). Here, with reference to FIG. 1, FIG. 13 thru | or FIG. 21, the manufacturing method of the element substrate 91 is explained in full detail. First, as shown in FIGS. 13A and 13B, a Ta ₂ O ₅ film 70 serving as a base layer is formed on the upper substrate 1 with a thickness of about 0.1 μm (step P1). Te, the _Ta on 2 _{O 5} film 70, to form a TaW layer 350 containing W (tungsten) about 0.2 wt% at a thickness of about 0.1 [mu] m (step P2).

Next, as shown in FIGS. 14A and 14B, the TaW film 350 is patterned by dry etching (process P3). Thereby, in FIG. 14A, the first metal film 322 which is a component of the TFD element 21 is formed. On the other hand, on the substrate side corresponding to FIG. 14B, the TaW film 350 formed on the Ta ₂ O ₅ film 70 is removed.

Next, as shown in FIG. 15A, an insulating film 323 made of a Ta ₂ O ₅ film is formed with a thickness of about 0.02 μm on the first metal film 322 by an anodic oxidation method ( Step P4). In this step, the insulating film 323 is not formed on the substrate side shown in FIG.

Subsequently, the heat treatment A, that is, the annealing process A, is performed on the insulating film 323 and the like covering the first metal film 322 (process P5). The annealing process A is performed, for example, in an atmosphere such as nitrogen gas in an annealing apparatus under conditions of about 320 ° C. and a holding time of 30 minutes. By performing the annealing process A, the Ta ₂ O ₅ film as the insulating film 323 becomes a denser film, and the insulating film 323 that satisfies the design specifications can be formed.

Next, a chromium film is formed to a thickness of about 3000 mm on the Ta ₂ O ₅ film 70 and the insulating film 323 (step P6, not shown), and then as shown in FIG. Then, the chromium film is patterned to form second metal films 336 and 316, respectively (process P7). Thereby, the data line 32 is formed. Further, as shown in FIG. 16B, the first conductive layer 35 a that is an element of the data line 32 and the external connection wiring 35 is formed on the Ta ₂ O ₅ film 70, respectively. Note that the first conductive layer 32a, which is an element of the terminal portion 32x, is formed on the Ta ₂ O ₅ film 70 corresponding to the region E20. In this step, the scanning line 31 including the region where the terminal portion 31ba corresponding to FIG. 1 or 3 is to be formed is also formed of a chromium film (not shown).

Next, as shown in FIG. 17A, an extra TaW film used for anodizing in the above process, strictly speaking, an extra first metal having an insulating film 323 formed on the surface. The film 322 is separated from the Ta ₂ O ₅ film 70 (process P8). Thereby, the TFD element 21 including the first TFD element 21a and the second TFD element 21b is formed.

  Next, a first transparent conductive film that characterizes the present invention is formed (process P9). That is, as shown in FIG. 17B, the first transparent conductive film made of ITO is formed on the first conductive layer 32a and the first conductive layer 35a made of chrome film to a thickness of about 500 mm. . Thus, the second conductive layer 32b is formed on the first connection portion 32a, and the second conductive layer 35b is formed on the first conductive layer 35a.

  In this step, instead of the first transparent conductive film made of ITO, the material for forming the second conductive layer 32b and the second conductive layer 35b is a material that is not easily oxidized even if heat treatment is performed, or Even if it is oxidized by such heat treatment, it may be formed of a molybdenum-based material from which the oxide film can be easily removed by washing or the like. In addition, since the 2nd conductive layer 32b and the 2nd conductive layer 35b are formed on the 1st connection part 32a and the 1st conductive layer 35a which do not have transparency, respectively, it is not essential to have transparency.

  In this step, the first transparent conductive material is formed on the region where the terminal portion 31ba corresponding to FIG. 1 or 3 is to be formed, that is, on the chromium film (not shown) formed in the region in step P6. A film or a molybdenum-based material is stacked (not shown).

  Further, in this step, as shown in FIG. 18, a first transparent conductive film may be formed on the second metal film 336 where the contact hole 25a is to be formed in a later-described step. In this case, a conductive film 380 made of the first transparent conductive film is formed on the second metal film 336 to a thickness of about 500 mm (see also FIG. 7). Since the conductive film 380 is formed of a material having transparency, the conductive film 380 may be formed larger than the line width of the second conductive film 336 in the plan view of FIG. This is because the aperture ratio does not decrease. However, an object of the present invention is to prevent an oxide film from being formed on the surface of the conductive film 380 or the like as will be described later and a contact resistance of a portion electrically connected to the conductive film 380 or the like from increasing. Therefore, it is not necessary to form the conductive film 380 particularly large.

  Next, the annealing process B is executed (process P9). That is, after the first transparent conductive film is formed, the annealing process B is performed before the overlayer 25 and the pixel electrode are formed. The annealing process B is performed to make the characteristics of the TFD element 21 constant characteristics determined by specifications. In particular, the annealing treatment B is performed under certain conditions, for example, 230 to 280 ° C. (retention time 60 minutes or less, desirably 30 minutes or less), preferably 250 ° C. (retention time 5 minutes). The contact resistance between the pixel electrode 10 and the TFD element 21 can be reduced by adapting the insulating film 323 and the second metal films 336 and 316.

Next, overlayer patterning is performed (process P11). Specifically, as shown in FIG. 19A, an overlayer 25 that is an insulating film is formed on the Ta ₂ O ₅ film 70, the TFD element 21, and the data line 32 to a thickness of about 2.0 μm. . As an overlayer material, an acrylic resin having photosensitivity and transparency is suitable. At the same time, a contact hole 25a having a substantially trapezoidal shape reversed in a sectional view is formed in a part on the second metal film 336 by a stepper or a batch exposure machine. In this step, the overlayer 25 is not formed on the substrate side shown in FIG.

  Next, in the above-described process P9, when the second conductive layer 32b and the second conductive layer 35b are formed of a molybdenum-based material, the process proceeds to the cleaning process P11 '. Otherwise, the process proceeds to the process P12. When the process shifts to the process P11 ', the element substrate which is a semi-finished product is washed with water or the like. Thereby, the following effect can be obtained. That is, an oxide film is formed on the surface of the elements of the second conductive layer 32b, the second conductive layer 35b, and the terminal portion 31ba made of a molybdenum-based material by the heat treatment in the above steps P10 and P11. By performing the process P11 ′, the oxide films formed on the surfaces of the elements of the second conductive layer 32b, the second conductive layer 35b, and the terminal portion 31ba can be easily removed.

  When the process proceeds to Step P12, a second transparent conductive film is formed. Specifically, as shown in FIG. 20A, a pixel electrode made of a second transparent conductive film such as ITO is formed on the overlayer 25 and the second metal film 336 in the contact hole 25a. The second transparent conductive film can be made of the same material as the first transparent conductive film. Thereby, the pixel electrode 10 and the second metal film 336 are electrically connected in the contact hole 25a. In this step, in the case of the configuration shown in FIG. 18, the pixel electrode 10 is formed on the conductive film 380 located in the contact hole 25a and formed on the second metal film 336. In this case, the pixel electrode 10 and the conductive film 380 are electrically connected in the contact hole 25a.

  In this step, as shown in FIG. 20B, a second transparent conductive film is formed on the elements of the second conductive layer 32b, the second conductive layer 35b, and the terminal portion 31ba. Thereby, the third conductive layer 32c made of a material such as ITO is formed on the second conductive layer 32b, and the third conductive layer 35c made of a material such as ITO is also formed on the second conductive layer 35b. Is formed. The second transparent conductive film is also formed on the element of the terminal portion 31ba (not shown). That is, by this process, the terminal portion 32x of the data line 32, the external connection wiring 35, and the terminal portion 31ba (not shown, refer to FIG. 1 or FIG. 3) are formed.

  Next, other components are attached (process P13). Specifically, as shown in FIGS. 21A and 21B, a retardation plate (¼ wavelength plate) 13 and a polarizing plate 14 are attached to the lower side of the upper substrate 1. Further, as shown in FIG. 21B, the X driver IC 34 and the FPC 90 are attached, respectively. That is, the third conductive layer 32c, which is an element of the terminal portion 32x, and each bump 34a on the output side of the X driver IC 34 are electrically connected via the ACF 80, and one end side of the external connection wiring 35 The bumps 34b on the input side of the driver IC 34 are electrically connected via the ACF 80. Although not particularly shown in FIG. 21, the same method is used to electrically connect one end side of the scanning line 31 and each bump 33a on the input side of the Y driver IC 33 via the ACF 80, and to connect the external connection wiring. 35 is electrically connected to the bumps 33b on the output side of the Y driver IC 33 via the ACF 80 (refer to FIG. 1 or FIG. 3 for the connection state). Further, in this step, each wiring 90 a of the FPC 90 and the other end side of the external connection wiring 35 are electrically connected via the ACF 80.

  Returning to FIG. 11, next, the color filter substrate shown in FIG. 2 is manufactured by a known method (step S2), and the element substrate 91 and the color filter substrate 92 are bonded together via the seal member 3 (step S3). . Next, liquid crystal is injected into an opening (not shown) formed between the element substrate 91 and the color filter substrate 92 to seal the opening (step S4). Next, by mounting other components, the liquid crystal display device 100 of the present invention shown in FIG. 2 is manufactured.

  According to the above method for manufacturing a liquid crystal display device, after the chromium film patterning step P7 and before the annealing process B step P10, the first conductive layer 32a, the first conductive layer 35a, etc. In addition, the first transparent conductive film made of ITO or the like, that is, the second conductive layer 32b and the second conductive layer 35b are formed. For this reason, heat is not directly applied to the surfaces of the first conductive layer 32a and the first conductive layer 35b, thereby oxidizing the surfaces of the first conductive layer 32a and the first conductive layer 35a. An oxide film can be prevented from being formed. Therefore, the contact resistance between the first conductive layer 35a and the first conductive layer 32a and the second conductive layer 35b or the second conductive layer 32b is kept low, and the external connection wiring electrically connected to the FPC 90 It is possible to prevent the resistance value from increasing from the other end side of 35 to one end side of the external connection wiring 35 electrically connected to the Y driver IC 33 or the X driver IC 34. In a preferred example, an average from the other end side of the external connection wiring 35 electrically connected to the FPC 90 to one end side of the external connection wiring 35 electrically connected to the Y driver IC 33 or the X driver IC 34 is obtained. The resistance value can be set to about 100Ω or less. Thereby, it is possible to prevent the Y driver IC and the X driver IC 34 from malfunctioning when the liquid crystal display device 100 is driven.

  Further, in this manufacturing method, after the chromium film patterning step P7 and before performing the annealing process B step P10, an element made of ITO or the like is formed on the element made of chromium which is a constituent element of the terminal portion 31ba. In addition, conductive layers 380 made of ITO or the like are formed on the second metal film 336 of the TFD element 21 as necessary. Therefore, the former can prevent an oxide film from being formed on the surface of the chromium element of the terminal portion 31ba, and the contact resistance between the conducting member 7 disposed in the seal member 3 and the terminal portion 31ba is reduced. It can be prevented from becoming high. Further, the latter can prevent the contact resistance between the pixel electrode 10 and the second metal film 336 of the TFD element 21 from increasing.

[Modification]
In the above embodiment, the present invention is applied to the transflective liquid crystal display device 100. However, the present invention is not limited to this, and the present invention can also be applied to a reflective or transmissive liquid crystal display device. In the above embodiment, the TN liquid crystal is applied to the liquid crystal display device 100. However, the liquid crystal display device 100 is not limited thereto, and the liquid crystal having negative dielectric anisotropy is applied to the liquid crystal display device 100. Also good. Furthermore, in the above embodiment, the present invention is applied to the element substrate 91 having the TFD element 21, but the present invention is not limited to this, and the present invention is applied to an element substrate having a switching element such as a TFT (Thin Film Transistor). It doesn't matter.

[Electronics]
Next, an embodiment in which the liquid crystal display device 100 according to the present invention is used as a display device of an electronic apparatus will be described.

  FIG. 22 is a schematic configuration diagram showing the overall configuration of the present embodiment. The electronic apparatus shown here includes the liquid crystal display device 100 and a control unit 410 that controls the liquid crystal display device 100. Here, the liquid crystal display device 100 is conceptually divided into a panel structure 403 and a drive circuit 402 composed of a semiconductor IC or the like. Further, the control means 410 includes a display information output source 411, a display information processing circuit 412, a power supply circuit 413, and a timing generator 414.

  The display information output source 411 includes a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), a storage unit such as a magnetic recording disk or an optical recording disk, and a tuning circuit that tunes and outputs a digital image signal. The display information is supplied to the display information processing circuit 412 in the form of an image signal of a predetermined format based on various clock signals generated by the timing generator 414.

  The display information processing circuit 412 includes various well-known circuits such as a serial-parallel conversion circuit, an amplification / inversion circuit, a rotation circuit, a gamma correction circuit, and a clamp circuit, and executes processing of input display information to obtain image information. Are supplied to the drive circuit 402 together with the clock signal CLK. The driving circuit 402 includes a scanning line driving circuit, a data line driving circuit, and an inspection circuit. The power supply circuit 413 supplies a predetermined voltage to each of the above-described components.

  Next, specific examples of electronic devices to which the liquid crystal display device 100 according to the present invention can be applied will be described with reference to FIG.

  First, an example in which the liquid crystal display device 100 according to the present invention is applied to a display unit of a portable personal computer (so-called notebook personal computer) will be described. FIG. 23A is a perspective view showing the configuration of this personal computer. As shown in the figure, the personal computer 710 includes a main body 712 having a keyboard 711 and a display 713 to which the liquid crystal display panel according to the present invention is applied.

  Next, an example in which the liquid crystal display device 100 according to the present invention is applied to a display unit of a mobile phone will be described. FIG. 23B is a perspective view showing the configuration of this mobile phone. As shown in the figure, the cellular phone 720 includes a plurality of operation buttons 721, a reception port 722, a transmission port 723, and a display unit 724 to which the liquid crystal display device 100 according to the present invention is applied.

  Note that, as an electronic device to which the liquid crystal display device 100 according to the present invention can be applied, in addition to the personal computer shown in FIG. 23A and the mobile phone shown in FIG. Type / monitor direct-view type video tape recorder, car navigation device, pager, electronic notebook, calculator, word processor, workstation, videophone, POS terminal, digital still camera, etc.

  Further, the present invention is not limited to a liquid crystal display device, but also an electroluminescence device, an organic electroluminescence device, a plasma display device, an electrophoretic display device, and a device using an electron-emitting device (Field Emission Display and Surface-Conduction Electron-Emitter Display). The present invention can be similarly applied to various electro-optical devices such as the above.

FIG. 3 is a plan view showing a configuration of electrodes and wirings of the liquid crystal display device of the present invention. The cross-sectional structure of a liquid crystal display device is shown. The top view which shows the structure of the electrode of an element substrate, wiring, etc. FIG. The top view which shows the structure of the electrode of a color filter board | substrate. The top view which shows the layout of the pixel electrode etc. in an element substrate. FIG. 6 is a partial cross-sectional view near a contact hole in FIG. 5. The fragmentary sectional view near the contact hole according to another embodiment. The partial top view which shows the electrical structure of the wiring for external connection in an element board | substrate. The fragmentary sectional view which shows the electrical structure of the wiring for external connection in an element substrate. The fragmentary top view and fragmentary sectional view which show the other example of a form for wiring for external connection. 3 is a flowchart showing a method for manufacturing a liquid crystal display device of the present invention. The flowchart which shows the manufacturing method of an element substrate. The fragmentary sectional view and partial plan view which show the manufacturing process of an element substrate. The fragmentary sectional view and partial plan view which show the manufacturing process of an element substrate. The fragmentary sectional view and partial plan view which show the manufacturing process of an element substrate. The fragmentary sectional view and partial plan view which show the manufacturing process of an element substrate. The fragmentary sectional view and partial plan view which show the manufacturing process of an element substrate. The fragmentary sectional view and partial plan view which show the manufacturing process of an element substrate. The fragmentary sectional view and partial plan view which show the manufacturing process of an element substrate. The fragmentary sectional view and partial plan view which show the manufacturing process of an element substrate. The fragmentary sectional view and partial plan view which show the manufacturing process of an element substrate. 1 is a circuit block diagram of an electronic apparatus to which a liquid crystal display device according to an embodiment is applied. An example of an electronic apparatus to which the liquid crystal display device according to the embodiment is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Upper substrate, 2 Lower substrate, 3 Seal member, 6 Colored layer, 7 Conductive member, 8 Scan electrode, 10 Pixel electrode, 25 Over layer, 25a Contact hole, 31 Scan line, 31ba Terminal part, 32 Data line, 32x Terminal portion, 33a, 33b, 34a, 34b Bump, 35 External connection wiring, 33 Y driver IC, 34 X driver IC, 21 TFD element, 91 element substrate, 92 color filter substrate, 100 liquid crystal display device

Claims (16)

A substrate,
An electro-optical material is sealed between an electro-optical device substrate having a plurality of external connection terminals formed in an overhanging region on the substrate and electrically connected to an external circuit, and a counter substrate having a scanning electrode. An electro-optical device comprising:
The plurality of external connection terminals are laminated in the order of a first metal layer and a second conductive layer, and the second conductive layer is made of ITO, molybdenum, an alloy containing molybdenum as a main component, or a material having an oxidation resistance. An electro-optical device formed. A plurality of wirings formed on the substrate and having a plurality of terminal portions;
A switching element formed on the substrate and electrically connected to a part of the plurality of wirings;
A pixel electrode formed on an insulating film covering the switching element and electrically connected to the switching element;
The switching element includes a layer made of the same material as the first metal layer,
The external connection terminal includes a third conductive layer laminated on the second conductive layer and formed of ITO, molybdenum, an alloy containing molybdenum as a main component, or a material having an oxidation resistance. The electro-optical device according to claim 1. A driving IC on the substrate;
The electro-optical device according to claim 2, wherein the external connection terminal includes a portion formed continuously with the plurality of wirings and connected to a terminal provided in the driving IC. The plurality of wirings are formed on the substrate corresponding to a frame region, and a plurality of terminal portions are formed on one end side of the plurality of wirings,
The electro-optical device according to claim 2, wherein the plurality of terminal portions are stacked in the order of the first metal layer, the second conductive layer, and the third conductive layer. The electro-optical device substrate and the counter substrate are bonded via a seal member,
A plurality of terminal portions are further formed on the other end side of the plurality of wirings, and the plurality of terminal portions are laminated in the order of the first metal layer, the second conductive layer, and the third conductive layer. And
The electro-optical device according to claim 4, wherein the third conductive layer is connected to the scan electrode through conductive particles.   The contact hole formed in the insulating film has a conductive layer made of the same material as the third conductive layer between the pixel electrode and the switching element, and the pixel electrode and the switching element The electro-optical device according to claim 2, wherein the electro-optical device is electrically connected via a layer.   The first metal layer is made of chromium, and the second and third conductive layers are made of ITO, molybdenum, an alloy containing molybdenum as a main component, or a material having an oxidation resistance. The electro-optical device according to claim 1.   Resistance value from the portion of the external connection terminal electrically connected to the terminal provided in the driving IC to the other end side of the external connection wiring electrically connected to the external circuit The electro-optical device according to claim 1, wherein is set to be approximately 100Ω or less.   An electronic apparatus comprising the electro-optical device according to claim 1 as a display unit. A substrate,
A plurality of external connection terminals formed in an overhang region on the substrate and electrically connected to an external circuit;
The plurality of external connection terminals are laminated in the order of a first metal layer and a second conductive layer, and the second conductive layer is made of ITO, molybdenum, an alloy containing molybdenum as a main component, or a material having an oxidation resistance. A substrate for an electro-optical device, which is formed. A first conductive layer forming step of forming a plurality of wirings, switching elements, and first conductive layers of external connection terminals on the substrate;
A second conductive layer forming step of forming a second conductive layer by forming a first metal film on the first conductive layer after forming the first conductive layer of the external connection terminal;
A heat treatment step of heat-treating the switching element after the step of forming the second conductive layer;
Forming an insulating film on the substrate, the plurality of wirings and the switching element;
Forming a contact hole in the insulating film;
A second conductive layer is formed on the insulating film to form a pixel electrode, and the pixel electrode and the switching element are electrically connected through the contact hole, and the external connection terminal And forming a third conductive layer on the second conductive layer to form a third conductive layer to form an electro-optical device substrate. Device manufacturing method. The second conductive layer is molybdenum or an alloy containing molybdenum as a main component,
12. The method of manufacturing an electro-optical device according to claim 11, further comprising a cleaning step of cleaning at least the second conductive layer with water between the heat treatment step and the third conductive layer forming step. Forming a first conductive layer on the other end side of the plurality of wirings in the first conductive layer forming step;
Forming a second conductive layer on the first conductive layer between the first conductive layer forming step and the second conductive layer step;
Forming a third conductive layer on the second conductive film in the third conductive layer forming step;
The electro-optical device substrate and the counter substrate are bonded together via a seal member having a plurality of conductive particles, and the third conductive layer on the other end side of the plurality of wirings and the plurality of conductive particles are electrically connected. The method of manufacturing an electro-optical device according to claim 11, further comprising a step of connecting to the electro-optical device. Forming a first conductive layer on one end side of the data line in the first conductive layer forming step;
Forming a second conductive layer on the first conductive layer between the first conductive layer forming step and the second conductive layer forming step;
Forming a third conductive layer on the second conductive layer in the third conductive layer forming step;
The electro-optical device according to claim 11, further comprising a step of electrically connecting the third conductive layer on the one end side of the data line and the driving IC. Production method. Forming a first conductive layer on one end side of the plurality of wirings in the first conductive layer forming step;
Forming a second conductive layer on the first conductive layer between the first conductive layer forming step and the second conductive layer forming step;
Forming a third conductive layer on the second conductive layer in the third conductive layer forming step;
15. The electro-optical device according to claim 11, further comprising a step of electrically connecting the third conductive layer on the one end side of the plurality of wirings and the driving IC. Manufacturing method. Forming the switching element by sequentially forming a first metal film, an insulating film, and a second metal film in the first conductive layer forming step;
Forming a conductive layer formed simultaneously with the third conductive layer on the second metal film between the first conductive layer forming step and the second conductive layer forming step;
16. The electricity according to claim 11, further comprising a step of electrically connecting the pixel electrode and the conductive layer through the contact hole in the third conductive layer forming step. Manufacturing method of optical device.

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