JP2015161700A - Electro-optic device and method for manufacturing electro-optic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electro-optic device capable of improving both display function reliability and packaging reliability.SOLUTION: An electro-optic device comprises: a first insulating film 41; a wiring layer 43 formed on the first insulating film 41; a second insulating film 42 formed so as to cover the first insulating film 41 and the wiring layer 43; a pixel electrode 44 formed on the second insulating film 42 and electrically connected to the wiring layer 43 via a first contact hole 37 formed in the second insulating film 42; and a packaging terminal 15 formed on the second insulating film 42, electrically connected to the wiring layer 43 via a second contact hole 38 formed on the second insulating film 42, and including a first layer 47 and a second layer 48 which is a lower layer of the first layer 47. The pixel electrode 44 and the second layer 48 are formed in the same layer.

Description

  The present invention relates to an electro-optical device and a method for manufacturing the electro-optical device.

In a flat panel display device such as a liquid crystal display device, an image is formed by controlling display light (including modulated light and reflected light) for each pixel, generally using a pixel electrode. . In a transmissive display device such as a liquid crystal display device, the transparency of ITO (indium oxide / tin alloy) or IZO (indium oxide / zinc alloy) as a material for forming a pixel electrode from the viewpoint of light transmittance and corrosion resistance. Conductive materials have been used.
On the other hand, in a reflective display device such as an electrophoretic display device, it is preferable that one of the pair of electrodes located on the opposite side of the display surface does not need light transmission, but rather has reflectivity. Therefore, for example, as shown in Patent Document 1, an electro-optical device is proposed in which the one electrode is made of a conductive film in which an Al (aluminum) film and a thin film made of molybdenum containing an aluminum oxide are stacked. ing.
Further, as a method for electrically connecting the electro-optical device and the external drive circuit, there is a method using wire bonding for connecting the mounting terminal of the electro-optical device and the terminal of the external drive circuit with a bonding wire in order to improve reliability. Can be mentioned. In that case, in order to improve the bonding property, a method of performing plating on the Al-based mounting terminal is also used.

JP 2009-230061 A

  However, since the electrophoretic display device displays charged electrophoretic particles by driving with an electric field, a high voltage of about 10 V is applied, and the pixel electrode is applied to a dispersion medium in which electrophoretic particles are dispersed. It is conceivable that a contacting structure is adopted. For this reason, the pixel electrode and mounting terminal must be durable enough to prevent defects such as corrosion of the pixel electrode and mounting terminal even if a high voltage is applied to the pixel electrode or mounting material. is there. Further, higher durability is required due to an increase in the number of driving times and an improvement in driving (rewriting) speed, and there is a problem that the Al-type film single layer structure is uneasy in terms of durability. Moreover, performing the plating process to improve the durability has a problem that man-hours and manufacturing costs increase.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 An electro-optical device according to this application example covers a first insulating film, a wiring layer formed on the first insulating film, and the first insulating film and the wiring layer. A second insulating film formed on the second insulating film, and electrically connected to the wiring layer through a first contact hole formed on the second insulating film. A pixel electrode is formed on the second insulating film, and is electrically connected to the wiring layer through a second contact hole formed in the second insulating film, and the first layer and the first layer A mounting terminal having a second layer which is a lower layer of the first layer, wherein the pixel electrode and the second layer are formed of the same layer.

  According to this application example, the configuration of the pixel electrode and the configuration of the mounting terminal can be made different. Therefore, with such a configuration, it is possible to improve both the reliability of the display function and the reliability of the mounting.

  Application Example 2 In the electro-optical device according to the application example, the first layer is made of Al or an Al alloy, and the second layer is made of Ti or a Ti alloy. To do.

  With such a configuration, the reliability can be improved by forming the pixel electrode from Ti or a Ti alloy. Moreover, wire bonding property can be improved by forming the 1st layer which is the upper layer of a mounting terminal with Al or Al alloy.

  Application Example 3 In the electro-optical device according to the application example, the first layer is formed of an AlCu alloy or an AlNd alloy.

  With such a configuration, the wire bonding property can be further improved.

  Application Example 4 In the electro-optical device according to the application example described above, the thickness of the first layer is 400 nm or more.

  In the electro-optical device having such a configuration, the wire bonding property can be further improved by setting the thickness of the Al layer or the Al alloy layer of the first layer to 400 nm or more.

Application Example 5 In the electro-optical device manufacturing method according to this application example, a step of sequentially forming a first insulating film, a wiring layer, and a second insulating film on a substrate; Removing a predetermined region of the insulating film to form a first contact hole and a second contact hole reaching the wiring layer; and a second layer made of Ti or Ti alloy on the second insulating film. Forming a layer; and patterning the second layer to form an island-shaped first pattern including the first contact hole and an island-shaped second pattern including the second contact hole. And a process of
Forming a first layer made of Al or an Al alloy covering the second insulating film, the first pattern, and the second pattern; patterning the first layer; and Forming an island-shaped pattern covering the pattern.

  With such a manufacturing method, a first pattern composed of a single layer of Ti or Ti alloy, a second pattern having a laminated structure of a layer composed of Ti or Ti alloy and a layer composed of Al or Al alloy, Can be formed while suppressing an increase in manufacturing cost. Therefore, for example, in an electro-optical device including a pixel electrode and a mounting terminal, both of the above elements can be formed of different materials, and an electro-optical device having both display properties and durability can be obtained at low cost.

1 is a schematic perspective view illustrating a configuration of an electrophoretic display device according to an embodiment. FIG. 2 is a schematic cross-sectional view illustrating a structure of a pixel and the like in the electrophoretic display device of the present embodiment. The figure which planarly viewed the mounting terminal and the recessed part. The expanded sectional view of the edge part of a mounting terminal. The figure which shows the condition where a bonding wire is mounted in a mounting terminal. The schematic sectional drawing which shows the manufacturing method of the mounting terminal of this embodiment.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. Note that the drawings to be used are appropriately enlarged or reduced so that the part to be described can be recognized.
In the following embodiments, for example, when “on the substrate” is described, the substrate is disposed so as to be in contact with the substrate, or is disposed on the substrate via another component, or the substrate. It is assumed that a part is arranged so as to be in contact with each other and a part is arranged via another component.

(First embodiment)
<Electro-optical device>
The electro-optical device of the present embodiment is characterized by pixel electrodes and mounting terminals. An active drive type electrophoretic display device will be described as an example of the electro-optical device, and will be described with reference to FIGS. FIG. 1 is a schematic perspective view showing the configuration of an electrophoretic display device, and FIG. 2 is a schematic cross-sectional view showing the structure of pixel electrodes and the like in the electrophoretic display device.

As shown in FIG. 1, an electrophoretic display device 100 as an electro-optical device according to this embodiment includes an element substrate 11 and a counter substrate 12 that are arranged to face each other. An electrophoretic layer 20 (see FIG. 2) as a display layer is disposed between the pair of substrates. In the present embodiment, both of the pair of substrates are square, but the present invention is not limited to this shape.

The electrophoretic layer 20 has a plurality of regions partitioned in a matrix between the pair of substrates, and each of the plurality of regions has a function as a pixel P. That is, the display area E is composed of a plurality of pixels P arranged in a matrix.
In the present embodiment, in the display area E, the row direction of the pixels P arranged in a matrix is defined as the X direction, the column direction of the pixels P is defined as the Y direction, the element substrate 11 faces the counter substrate 12, and the X direction. The direction orthogonal to the Y direction will be described as the Z direction. Further, viewing from the counter substrate 12 side in the Z direction is referred to as a plan view.
Further, the arrangement pattern of the pixels P is not limited to the above matrix form, and for example, a delta arrangement pattern can be adopted.

Here, the element substrate 11 is larger than the counter substrate 12 on one side of the four sides, and the element that protrudes from the counter substrate 12 when the element substrate 11 and the counter substrate 12 are arranged to face each other at a predetermined position. A portion of the substrate 11 serves as a terminal portion 11a. A plurality of mounting terminals 15 are arranged in the terminal portion 11a. Each of the mounting terminals 15 of the electrophoretic display device 100 and an external circuit (not shown) are electrically connected by a bonding wire 13.
The electrophoretic display device 100 is a light-receiving device in which a display is recognized using light emitted from the outside. The electrophoretic display device 100 includes a transistor for switching control of the pixel P on the element substrate 11 side, wiring connected to the transistor, and the like, and the mounting terminal 15 is connected to the wiring and the like. Therefore, the electrophoretic display device 100 is driven by a signal or power supply from an external circuit transmitted via the mounting terminal 15.

  FIG. 2 is a schematic cross-sectional view showing the structure of the electrophoretic display device 100 along the Y direction of FIG. In FIG. 2, the bonding wire 13 is not shown. As shown in FIG. 2, the electrophoretic display device 100 includes an electrophoretic layer 20 disposed between the element substrate 11 and the counter substrate 12, and a thin film transistor (hereinafter referred to as “TFT”) formed on the element substrate 11. It is composed of 30 etc.

The element substrate 11 is an insulating substrate such as glass or plastic. As described above, since the electrophoretic display device 100 is a reflective display device, the element substrate 11 does not need to be light transmissive. Therefore, an opaque substrate such as ceramic can be used.
Since the counter substrate 12 is disposed on the display surface side and requires translucency, a transparent substrate such as glass or plastic is used.

A TFT 30 is formed on the element substrate 11. The TFT 30 includes a semiconductor layer 33 patterned in an island shape, a gate insulating film 40 formed so as to cover substantially the entire surface of the element substrate 11 including the semiconductor layer 33, a gate electrode 36, and the like.
The semiconductor layer 33 is made of, for example, polycrystalline silicon. Although not shown, the semiconductor layer 33 is divided into a channel region and a source / drain region due to a difference in concentration of implanted impurities. A region overlapping with the gate electrode 36 is a channel region, and regions on both sides thereof are a source / drain region. The TFT 30 is covered with a first interlayer insulating film 41. The first interlayer insulating film 41 is made of, for example, silicon oxide or nitride.

A contact hole 34 is formed in a region overlapping the source / drain region in the first interlayer insulating film 41. The contact hole 34 is formed by locally etching the first interlayer insulating film 41 by photolithography.
On the first interlayer insulating film 41, a wiring layer 43 connected to the source / drain region through the contact hole 34 is formed. In the present embodiment, a layer made of a conductive material formed between the first interlayer insulating film 41 and a second interlayer insulating film 42 described later is referred to as a wiring layer 43. The contact hole 34 on the mounting terminal 15 side on the left side of the figure is not shown.
Specifically, the wiring layer 43 is a source line or a relay electrode. The wiring layer 43 is made of an Al alloy or the like, and is formed collectively by patterning the same material layer by a photolithography method.

On the element substrate 11 on which the wiring layer 43 and the like are formed, a second interlayer insulating film 42 made of, for example, an acrylic resin is formed. A pixel electrode 44 and a mounting terminal 15 are formed on the second interlayer insulating film 42. The pixel electrode 44 is a conductive material layer patterned in an island shape, and is formed for each pixel P (see FIG. 1). The material for forming the pixel electrode 44 and the mounting terminal 15 will be described later.
The pixel electrode 44 is connected to the wiring layer 43 through the first contact hole 37 formed in the second interlayer insulating film 42. More specifically, the pixel electrode 44 is connected to the TFT 30 via the first contact hole 37, the wiring layer 43, and the contact hole 34. Therefore, the pixel electrode 44 can be individually controlled by the TFT 30.

  The mounting terminal 15 is also a conductive material layer patterned in an island shape. As described above, the element substrate 11 is larger than the counter substrate 12 on one side, and this side protrudes from the sealing material 39 described later. The mounting terminal 15 is formed in the terminal part 11a (refer FIG. 1) which is the area | region which protruded.

A part of the mounting terminal 15 is formed in a recess 50 formed by etching the second interlayer insulating film 42 as shown. The portion formed in the recess 50 is a portion (region) to which the bonding wire 13 (see FIG. 1) is bonded.
The mounting terminal 15 is connected to the wiring layer 43 through a second contact hole 38 formed in the second interlayer insulating film 42. The first contact hole 37, the second contact hole 38, and the recess 50 are formed by locally etching the second interlayer insulating film 42 by a photolithography method, like the contact hole 34 described above. . Here, if a photosensitive acrylic resin material is used as a material for forming the second interlayer insulating film 42, the photosensitive acrylic resin material layer is exposed and developed by photolithography, and the first contact hole 37, the first A second interlayer insulating film 42 having two contact holes 38 and a recess 50 can be formed. In other words, the resist layer forming step in the step of locally etching the second interlayer insulating film 42 can be omitted.

  Further, a sealing material 39 is formed on the second interlayer insulating film 42 (precisely between the second interlayer insulating film 42 and the counter substrate 12). The sealing material 39 is made of an adhesive such as a thermosetting or ultraviolet curable epoxy resin, and is disposed along the outer edge of the counter substrate 12. That is, the sealing material 39 is annularly arranged so as to surround the display area E in plan view. Therefore, the element substrate 11 and the counter substrate 12 are disposed to face each other with the sealing material 39 interposed therebetween. The space formed by the pair of substrates of the element substrate 11 and the counter substrate 12 and the sealing material 39 is the electrophoretic layer 20.

More specifically, the electrophoretic layer 20 is disposed between the electrodes formed on both of the pair of substrates. In other words, it is disposed between the pixel electrode 44 formed on the element substrate 11 and the counter electrode 45 formed on the counter substrate 12. Since the counter electrode 45 requires light transmission like the counter substrate 12, it is formed of a transparent conductive material such as ITO (Indium Tin Oxide). Unlike the pixel electrode 44, the pixel electrode 44 is formed in substantially the entire display area E without being partitioned. Therefore, the counter electrode 45 functions as a common electrode for all the pixels P arranged in the display area E. In the present embodiment, the counter electrode 45 is formed on the inner side of the sealing material 39, but a mode in which the counter electrode 45 and the sealing material 39 overlap at the outer edge of the counter substrate 12 is also possible.
As described above, the pixel electrode 44 is formed for each pixel P and can be individually controlled by the TFT 30. Therefore, in the electrophoretic display device 100, a voltage can be arbitrarily applied between the pixel electrode 44 and the counter electrode 45 for each pixel P.

  The electrophoretic layer 20 includes a microcapsule 24 and an adhesive layer 46. The adhesive layer 46 is a sheet-like base material having adhesiveness on both sides, and the microcapsules 24 are spread on one side so as not to have a gap as much as possible. The other surface is attached on the element substrate 11 on which the pixel electrode 44 is formed. The adhesive layer 46 contains an electrolyte.

  The microcapsule 24 has a diameter of about 30 μm to 75 μm, and is disposed between the pixel electrode 44 and the counter electrode 45 so as to be in contact with each other in the Z direction (single layer) in the Z direction and in the X direction and the Y direction as illustrated. Has been. Therefore, the diameter of the microcapsule 24 is substantially the same as the dimension between the pixel electrode 44 and the counter electrode 45. On each pixel electrode 44, approximately the same number of microcapsules 24 are arranged.

  The microcapsule 24 is a spherical body in which a plurality of electrophoretic particles and a dispersion medium 23 are enclosed. The electrophoretic particles include black electrophoretic particles (hereinafter referred to as “black particles”) 21 and white electrophoretic particles (hereinafter referred to as “white particles”) 22. The outer shell (wall film) of the microcapsule 24 is formed using a transparent polymer resin such as an acrylic resin such as polymethyl methacrylate or polyethyl methacrylate, a urea resin, or gum arabic. ing.

  Examples of the dispersion medium 23 include water, alcohol solvents (methanol, ethanol, isopropanol, butanol, octanol, methyl cellosolve, etc.), esters (ethyl acetate, butyl acetate, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). ), Aliphatic hydrocarbons (pentane, hexane, octane, etc.), alicyclic hydrocarbons (cyclohexane, methylcyclohexane, etc.), aromatic hydrocarbons (benzene, toluene, benzenes having a long-chain alkyl group ( Xylene, hexylbenzene, hebutylbenzene, octylbenzene, nonylbenzene, decylbenzene, undecylbenzene, dodecylbenzene, tridecylbenzene, tetradecylbenzene)), halogenated hydrocarbons (methylene chloride, chloroform, tetrachloride) Element, and 1,2-dichloroethane), a carboxylic acid salt can be exemplified. In addition, oils such as silicone oil may be used. These substances can be used alone or as a mixture.

The black particles 21 are particles (polymer or colloid) made of a black pigment such as aniline black or carbon black. The white particles 22 are particles (polymer or colloid) made of a white pigment such as titanium dioxide, zinc white, and antimony trioxide. These pigments include electrolytes, surfactants, metal soaps, resins, rubbers, oils, varnishes, compound charge control agents, titanium-based coupling agents, aluminum-based coupling agents, silanes as necessary. A dispersant such as a system coupling agent, a lubricant, a stabilizer, and the like can be added.
The black particles 21 and the white particles 22 are charged and used so as to have opposite potentials. When the black particles 21 are used with positive charging, the white particles 22 are used with negative charging. Then, an image can be formed in the display area E by applying a voltage between the pixel electrode 44 and the counter electrode 45 for each pixel P by using the difference in potential.

  FIG. 2 shows a case where the pixel P is displayed in black. When performing black display, a direct current drive voltage is applied between the pixel electrode 44 and the counter electrode 45 to hold the counter electrode 45 at a relatively low potential and the pixel electrode 44 at a relatively high potential. As a result, the positively charged black particles 21 are attracted to the counter electrode 45, while the negatively charged white particles 22 are attracted to the pixel electrode 44. As a result, when the pixel P is viewed from the counter electrode 45 (counter substrate) side, black is recognized.

In addition, when white display is performed, a direct current drive voltage is applied between the pixel electrode 44 and the counter electrode 45 so that the counter electrode 45 has a relatively high potential and the pixel electrode 44 has a relatively low potential. Good. Thereby, the negatively charged white particles 22 are attracted to the counter electrode 45, while the positively charged black particles 21 are attracted to the pixel electrode 44. As a result, when the pixel P is viewed from the counter electrode 45 side, white is recognized.
Instead of the black particles 21 and the white particles 22, for example, particles using pigments such as red, green, and blue may be used. With such a configuration, color display can also be performed.

<Pixel electrode and mounting terminal>
As described above, in the electrophoretic display device 100, image display is performed by applying a voltage to the pixel electrode 44. The pixel electrode 44 (and the counter electrode 45) is in contact with the electrophoretic layer 20, specifically, the adhesive layer 46 and the microcapsule 24. Here, the adhesive layer 46 includes an electrolyte as described above. Therefore, the pixel electrode 44 is preferably formed of a material that can withstand the electrolyte, that is, a material having corrosion resistance.
Further, unlike the counter electrode 45, the pixel electrode 44 does not require light transmission, and needs to have reflectivity (light reflectivity) in order to improve display performance. Therefore, it is preferable to be formed of a highly reflective metal material.

  In addition, the mounting terminal 15 does not require reflectivity, but requires bonding properties, that is, a property that the bonding wire 13 is well connected. Since both the pixel electrode 44 and the mounting terminal 15 are formed on the second interlayer insulating film 42, it is preferable that they are formed in a common process as much as possible. Therefore, in the electrophoretic display device 100 of the present embodiment, the mounting terminal 15 has a stacked structure of the first layer 47 and the second layer 48 which is the lower layer, and the second layer is formed with the formation layer of the pixel electrode 44. By using the same layer, the above-described conditions are satisfied while suppressing an increase in manufacturing cost.

FIG. 3 is a plan view of the mounting terminal 15 and the recess 50 (viewed from the Z direction).
FIG. 4 is an enlarged cross-sectional view of the end portion of the mounting terminal 15. Hereinafter, the configuration of the mounting terminal 15 and the pixel electrode 44 will be described with reference to FIGS.

As described above and as shown in FIG. 2, the mounting terminal 15 is formed by the first layer 47 and the second layer 48 which is the lower layer, and the pixel electrode 44 is a single layer of the second layer 48. Is formed.
In the electrophoretic display device 100 of the present embodiment, the second layer 48 is made of Ti (titanium). The material for forming the second layer 48 is not limited to Ti, and TiN (titanium nitride) or an alloy of Ti and another metal can also be used. The layer thickness of the second layer 48 is preferably 50 nm to 300 nm, and is set to 200 nm in the electrophoretic display device 100 of the present embodiment.

  In the electrophoretic display device 100 of the present embodiment, the first layer 47 is made of AlCu (aluminum / copper alloy). The material for forming the first layer 47 is not limited to AlCu, and AlNd (aluminum-neodymium alloy) or an alloy of Al and another metal can also be used. The layer thickness of the first layer 47 is preferably 200 nm to 700 nm, and is set to 400 nm in the electrophoretic display device 100 of the present embodiment.

As shown in FIG. 3, the mounting terminal 15 includes a second contact hole 38 connected to the wiring layer 43 and a recess 50 formed at an interval from the second contact hole 38 in plan view. It is formed in an island shape. Therefore, the end portion (outer edge portion) of the mounting terminal 15 is located on the second interlayer insulating film 42 in the entire periphery.
As shown in FIG. 4, the layer thickness t1 of the first layer 47, that is, the AlCu layer, is thicker than the second layer 48, that is, the layer thickness t2 of the Ti layer. 48 or Ti layer is covered with a first layer 47 or AlCu layer.

<Effect>
The electrophoretic display device 100 of the present embodiment has the effects described below.
First, the improvement of the corrosion resistance of the pixel electrode 44 is mentioned. A pixel electrode made of a transparent conductive material such as ITO or IZO, which has been used in a conventional electrophoretic display device, has a problem that it has low reflectivity and display performance may be inferior. On the other hand, when a pixel electrode made of Al or an Al alloy is used in contact with a substance containing an electrolyte, there is a problem in corrosion resistance (durability).
Here, since Ti or Ti alloy is a metal material, it has reflectivity close to that of Al and has corrosion resistance equal to or higher than that of Al. Therefore, the electrophoretic display device 100 of the present embodiment includes the pixel electrode 44 at a level that can satisfy both the reflectivity and the corrosion resistance, and can achieve both display performance and reliability at a high level.

In addition, the electrophoretic display device 100 of this embodiment also has an effect of improving the bonding property of the mounting terminals 15.
FIG. 5 is a diagram illustrating a situation in which the bonding wire 13 is mounted on the mounting terminal 15. FIG. 5A is a view showing the mounting terminal 15 having a laminated structure of the AlCu film of the first layer 47 and the Ti film of the second layer 48 of this embodiment, and FIG. 5B is a comparative example. It is a figure which shows the mounting terminal 15a of the single layer structure as. In FIG. 5, only the second interlayer insulating film 42 is shown except for the elements related to the mounting terminal 15 (15 a), and other components are not shown and simplified.

  As shown in FIGS. 5A and 5B, the bonding wire 13 is mounted on the mounting terminal 15 (15a). The bonding wire 13 is mounted by bringing it into close contact with the mounting terminal 15 (15a) while applying a strong pressure to the tip of the bonding wire 13, thereby obtaining an electrical and mechanical connection. The bonding wire 13 in this embodiment consists of Al (aluminum), and a wire diameter is 50-100 micrometers, for example. The bonding wire 13 is not limited to Al.

  Therefore, during bonding (mounting), a strong pressure is applied to the mounting terminal 15 (15a) in the direction indicated by the arrow in the figure. In order to perform bonding well, it is necessary to disperse the pressure during bonding. The pressure distribution at the time of bonding is smoothly performed when there is an interlayer (boundary surface) between layers having different hardnesses. As shown in FIG. 5B, in the case of the mounting terminal 15a made of a single layer of the first layer, since there is no interlayer, the dispersibility of pressure during bonding is slightly inferior. On the other hand, the mounting terminal 15 according to the present embodiment is formed by laminating the first layer 47 on the second layer 48, as shown in FIG. Easy to be distributed.

  Further, in the mounting terminal 15 of the present embodiment, the fact that the first layer 47 made of the AlCu film is formed thicker than the second layer 48 made of the Ti film also has an effect on the pressure distribution during bonding. ing. The AlCu film has a lower hardness than the Ti film. Since the Ti film is covered with such a low hardness AlCu film, the pressure during bonding is easily absorbed. The fact that the end portion of the second layer 48 is completely covered with the first layer 47 is also effective in absorbing pressure during bonding.

  Further, the fact that the mounting terminal 15 is formed in the recess 50 is effective in absorbing pressure during bonding. The area of the film of both the first layer 47 and the second layer 48 is substantially enlarged by the recess 50. Therefore, even if the area in plan view is the same, a mounting terminal having a substantially larger surface area can be realized, and the bonding wire 13 can be satisfactorily connected.

  And the mounting terminal of this embodiment can be formed while suppressing an increase in the number of processes to a minimum. FIG. 6 is a schematic cross-sectional view showing a method for manufacturing the mounting terminal 15 of the present embodiment. Hereinafter, it demonstrates in order of a process. In FIG. 6, the elements other than those related to the formation of the pixel electrode 44 and the mounting terminal 15 are not illustrated and are simplified.

<Manufacturing method>
First, as shown in FIG. 6A, a wiring layer 43 is formed on the first interlayer insulating film 41, and the second interlayer insulating film further covers the first interlayer insulating film 41 and the wiring layer 43. A film 42 is formed.
Next, as shown in FIG. 6B, a predetermined region of the second interlayer insulating film 42 is locally removed by photolithography to form the recess 50, the first contact hole 37, and the second contact. A hole 38 is formed.

  Next, a Ti film is formed on the second interlayer insulating film 42 in which the recesses 50 and the like are formed. The film thickness is approximately 200 nm as described above. Then, the Ti film is patterned by a photolithography method, and as shown in FIG. 6C, a first region 51, which is a region where the pixel electrode 44 will be formed in the future, and a region where the mounting terminal 15 is formed. A second layer 48 made of a Ti film is formed in the second region 52. The pixel electrode 44 is composed of only the second layer 48. Therefore, the formation of the pixel electrode 44 is completed in this process.

Next, as shown in FIG. 6D, a first layer precursor 47a (AlCu film) is formed on the second interlayer insulating film 42 on which the pixel electrodes 44 and the like are formed. The film thickness is approximately 400 nm as described above.
Next, as shown in FIG. 6E, the first layer precursor 47a is patterned by photolithography so as to remain only in the second region 52, thereby forming the first layer 47 made of an AlCu film. To do. As described above, the first layer 47 is formed so as to cover the end portion of the second layer 48. Accordingly, the second layer 48 is precisely formed slightly inside the second region 52.

  Through the above steps, the mounting terminal 15 having a stacked structure of the first layer 47 and the second layer 48 and the pixel electrode 44 made of a single layer of the second layer 48 are formed. As shown in the drawing, the mounting terminal 15 is connected to the wiring layer 43 through the second contact hole 38, and the pixel electrode 44 is connected to the wiring layer 43 through the first contact hole 37.

  According to the manufacturing method of the electrophoretic display device 100 including the manufacturing process of the mounting terminal 15 and the pixel electrode 44, the mounting terminal 15 and the pixel electrode 44 have the same Ti layer as the second layer 48. The increase in man-hours is suppressed. Therefore, according to the manufacturing method described above, the electrophoretic display device 100 having both display performance and durability can be obtained at low cost.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. An electrophoretic display device including a pixel electrode is also included in the technical scope of the present invention. Various modifications other than the above embodiment are conceivable. Hereinafter, a modification will be described.

(Modification 1)
The electro-optical device to which the present invention is applicable is not limited to the electrophoretic display device 100. For example, an OLED (organic electroluminescence display device) can also be used as the electro-optical device. The OLED also has a mounting terminal, and if it is a top emission type, the pixel electrode does not need light transmittance. Therefore, by using the mounting terminal and the pixel electrode having the above-described configuration, an OLED having both display performance and reliability can be realized.

  DESCRIPTION OF SYMBOLS 11 ... Element board | substrate, 11a ... Terminal part, 12 ... Counter substrate, 13 ... Bonding wire, 15 ... Mounting terminal, 15a ... Mounting terminal, 20 ... Electrophoresis layer, 21 ... Black particle, 22 ... White particle, 23 ... Dispersion medium 24 ... microcapsule, 30 ... TFT, 33 ... semiconductor layer, 34 ... contact hole, 36 ... gate electrode, 37 ... first contact hole, 38 ... second contact hole, 39 ... sealing material, 40 ... gate insulation Films 41... First interlayer insulating film 42. Second interlayer insulating film 43. Wiring layer 44. Pixel electrode 45. Counter electrode 46. Adhesive layer 47 47 First layer 47 a. DESCRIPTION OF SYMBOLS 1 layer precursor, 48 ... 2nd layer, 50 ... Recess, 51 ... 1st area | region, 52 ... 2nd area | region, 100 ... Electrophoretic display apparatus.

Claims (5)

A first insulating film;
A wiring layer formed on the first insulating film;
A second insulating film formed to cover the first insulating film and the wiring layer;
A pixel electrode formed on the second insulating film and electrically connected to the wiring layer through a first contact hole formed in the second insulating film;
Formed on the second insulating film, electrically connected to the wiring layer through a second contact hole formed in the second insulating film, and the first layer and the first layer A mounting terminal having a second layer as a lower layer,
The electro-optical device, wherein the pixel electrode and the second layer are formed of the same layer.   The electro-optical device according to claim 1, wherein the first layer is made of Al or an Al alloy, and the second layer is made of Ti or a Ti alloy.   The electro-optical device according to claim 1, wherein the first layer is formed of an AlCu alloy or an AlNd alloy.   4. The electro-optical device according to claim 1, wherein a thickness of the first layer is 400 nm or more. 5. Forming a first insulating film, a wiring layer, and a second insulating film on the substrate in order;
Removing a predetermined region of the second insulating film to form a first contact hole and a second contact hole reaching the wiring layer;
Forming a second layer made of Ti or Ti alloy on the second insulating film;
Patterning the second layer to form an island-shaped first pattern including the first contact hole and an island-shaped second pattern including the second contact hole;
Forming a first layer made of Al or an Al alloy covering the second insulating film, the first pattern, and the second pattern;
Patterning the first layer to form an island pattern covering the second pattern;
A method for manufacturing an electro-optical device.

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