JP2008203484A - Electrooptical device, package structure for flexible circuit board, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrooptical device wherein electric connections are securely made while a short circuit between adjacent terminals is prevented even when pitch spaces of terminal portions of a flexible circuit board and a substrate are narrow, a package structure for the flexible circuit board, and electronic equipment. <P>SOLUTION: Disclosed is the electrooptical device including the substrate to which the flexible circuit board is electrically connected, where the substrate has a first terminal portion and the flexible circuit board has a second terminal portion. Either of the first terminal portion and the second terminal portion is a stud bump, and the flexible circuit board and substrate are fixed with an insulating adhesive while the first terminal portion and the second terminal portion are electrically connected to each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electro-optical device, a flexible circuit board mounting structure, and an electronic apparatus. In particular, the present invention relates to an electro-optical device including an electro-optical device substrate to which a flexible circuit board is electrically connected, a flexible circuit board mounting structure, and an electronic apparatus including such an electro-optical device.

  Conventionally, a liquid crystal device, an electroluminescence (EL) device, and the like are known as an aspect of an electro-optical device that displays an image. For example, a liquid crystal device modulates light passing through a liquid crystal material of a predetermined pixel by forming a plurality of pixels composed of opposing regions of electrodes and selectively turning on and off a voltage applied to the plurality of pixels. It is a device that displays images such as pictures and characters. In such a liquid crystal device, a flexible circuit board on which a wiring pattern is formed is used as a circuit board for driving a liquid crystal panel or a light source for the purpose of downsizing the device or adding various functions to the device. Some are configured to be connected to a substrate constituting the liquid crystal panel.

  As a method of connecting the flexible circuit board to the board, there is a mounting method using an anisotropic conductive adhesive. For example, as shown in FIG. 13, using an anisotropic conductive film (ACF) 330 in which conductive particles 329 are mixed in an insulating adhesive 328, an extraction electrode (Outer) of a glass substrate 301 constituting a liquid crystal panel is used. There is known an OLB (Outer Lead Bonding) mounting method for electrically connecting Lead 304 and the connection electrode 327 of the flexible circuit board 321 (see, for example, Patent Document 1).

JP 2006-235295 A (FIG. 2)

  By the way, in recent years, with the miniaturization of the liquid crystal device, the pitch interval of the extraction electrode (Outer Lead) has been narrowed. As further miniaturization progresses in the future, the above-described mounting method using ACF may not be adopted. That is, when the distance between adjacent lead-out electrodes (Outer Lead) becomes small, there is a possibility that a short circuit between both electrodes may occur even when a small number of conductive particles in the ACF are connected.

In view of this, the inventors of the present invention have made diligent efforts, and in the mounting method for mounting the flexible circuit board on the board, at least one of the terminal on the flexible circuit board side or the terminal on the board side is a stud bump, and the flexible circuit board and The inventors have found that such a problem can be solved by fixing the substrate to the substrate with an insulating adhesive, and have completed the present invention.
That is, the present invention relates to an electro-optical device and a flexible circuit in which electrical connection is reliably performed while preventing a short circuit between adjacent terminals even when the pitch interval between the flexible circuit board and the terminal portion of the board is narrow. An object is to provide a mounting structure for a substrate. Another object of the present invention is to provide an electronic apparatus including such an electro-optical device.

According to the present invention, an electro-optical device includes a substrate to which a flexible circuit board is electrically connected. The substrate includes a first terminal portion, the flexible circuit substrate includes a second terminal portion, At least one of the terminal portion and the second terminal portion is a stud bump, and the flexible circuit board and the substrate are insulative with the first terminal portion and the second terminal portion being electrically connected. An electro-optical device characterized by being fixed with an adhesive is provided, and the above-described problems can be solved.
That is, either the flexible circuit board side or the terminal part on the board side is a stud bump, and by fixing the flexible circuit board and the board with an insulating adhesive, even when the pitch interval of the terminal parts is narrow, An electrical connection state can be ensured while preventing a short circuit between adjacent terminal portions. In addition, when connecting the flexible circuit board, the structure using the stud bumps makes it possible to use the flexibility of the flexible circuit board even if the height of the stud bumps varies slightly. Secure connection. Therefore, it is easy to reduce the outer shape of the substrate or the flexible circuit board, and it is possible to reduce the outer shape of the electro-optical device and to reduce the production cost.

In configuring the electro-optical device of the present invention, it is preferable that the stud bumps are arranged in a staggered manner.
With this configuration, even when the pitch interval between the terminal portions is narrowed, it is easy to secure the distance between the adjacent terminal portions, and the occurrence of a short circuit can be further reduced.

In configuring the electro-optical device of the present invention, at least one of the first terminal portion and the second terminal portion includes a plurality of stud bumps arranged in a direction in which the flexible circuit board is led out from the substrate. The plurality of stud bumps and the other terminal portion are preferably electrically connected at a plurality of locations.
By comprising in this way, the connection reliability of both terminals can be improved, narrowing the connection area | region of a 1st terminal part and a 2nd terminal part.

In configuring the electro-optical device of the present invention, it is preferable that the first terminal portion is arranged along the edge of the substrate.
By comprising in this way, the external shape of a board | substrate can be reduced in size by the part which can make the magnitude | size of a terminal part small.

In configuring the electro-optical device of the present invention, it is preferable that the insulating adhesive is any one of an insulating adhesive film, an insulating adhesive paste, and an underfill.
By comprising in this way, it can fix easily, aligning a flexible circuit board and a board | substrate.

In configuring the electro-optical device of the present invention, it is preferable that the semiconductor element is mounted on the substrate using an anisotropic conductive adhesive, and the insulating adhesive is a photocurable adhesive.
With this configuration, the semiconductor element is not exposed to heat during the mounting process of the flexible circuit board during manufacturing, and thermal damage can be prevented.

Another aspect of the present invention is a flexible circuit board mounting structure in which a flexible circuit board is mounted on a board, the board including a first terminal portion, and the flexible circuit board being a second terminal portion. And at least one of the first terminal portion or the second terminal portion is a stud bump, and the flexible circuit board and the first terminal portion and the second terminal portion are electrically connected to each other. A mounting structure of a flexible circuit board, wherein the board is fixed with an insulating adhesive.
That is, either the flexible circuit board side or the terminal part on the board side is a stud bump, and by fixing the flexible circuit board and the board with an insulating adhesive, even when the pitch interval of the terminal parts is narrow, An electrical connection state can be ensured while preventing a short circuit between adjacent terminal portions. In addition, when connecting the flexible circuit board, the structure using the stud bumps makes it possible to use the flexibility of the flexible circuit board even if the height of the stud bumps varies slightly. Secure connection. Accordingly, it is possible to easily reduce the outer shape of the substrate or the flexible circuit board, to reduce the outer shape of the electro-optical device, and to provide a flexible circuit board mounting structure that can reduce the production cost.

Still another embodiment of the present invention is an electronic apparatus including any of the electro-optical devices described above.
In other words, the electronic device is provided with an electro-optical device in which the terminal portions of the board and the flexible circuit board are narrowed while the electrical connection is ensured and the short circuit is reduced, so that the occurrence of malfunctions is reduced. can do.

  Hereinafter, exemplary embodiments of the electro-optical device, the flexible circuit board mounting structure, and the electronic apparatus according to the invention will be described in detail with reference to the drawings. However, this embodiment shows one aspect of the present invention and does not limit the present invention, and can be arbitrarily changed within the scope of the present invention.

[First Embodiment]
The first embodiment of the present invention is an electro-optical device including a substrate to which a flexible circuit board is electrically connected. In the electro-optical device of this embodiment, the substrate includes a first terminal portion, the flexible circuit substrate includes a second terminal portion, and at least one of the first terminal portion and the second terminal portion is a stud bump. In addition, the flexible circuit board and the substrate are fixed with an insulating adhesive in a state where the first terminal portion and the second terminal portion are electrically connected.
Hereinafter, the liquid crystal device as the electro-optical device according to the first embodiment of the present invention will be described as an example with reference to FIGS. 1 to 11 as appropriate. In addition, what attached | subjected the same code | symbol in each figure has shown the same member, and while abbreviate | omitting description suitably, the one part member is abbreviate | omitted suitably in each figure.

1. Overall Structure First, the overall structure of the liquid crystal device 10 according to the first embodiment of the present invention will be specifically described with reference to FIG. Here, FIG. 1 is a schematic perspective view of a liquid crystal device 10 according to the present embodiment. In FIG. 1, the upper surface is an image display surface.
As shown in FIG. 1, the liquid crystal device 10 of this embodiment includes a liquid crystal panel 20 in which two substrates 30 and 60 each having electrodes are bonded together with a sealing material and a liquid crystal material is disposed in a cell region. I have. An illumination device (not shown) is disposed on the back side of the liquid crystal panel 20.

  In addition, the element substrate 60 constituting the liquid crystal panel 20 has a substrate extending portion 60 </ b> T that protrudes outward from the outer shape of the counter substrate 30. A connection terminal (not shown) is formed on the surface of the substrate extension 60T that holds the liquid crystal material, and the semiconductor element 91 and the flexible circuit board 93 are connected to the connection terminal. Yes. Electronic components such as a light source and a connector are mounted on the flexible circuit board 93.

2. Liquid crystal panel As the liquid crystal panel 20, an active matrix type liquid crystal panel having a switching element such as a TFT element (Thin Film Transistor) or a TFD element (Thin Film Diode), or a passive matrix type liquid crystal having no switching element. Panels are typical. Among these, a configuration example of an active matrix type liquid crystal panel including a TFT element will be described.
FIG. 2 is a partial enlarged cross-sectional view of each pixel region of the active matrix type liquid crystal panel 20 having TFT elements. As shown in FIG. 2, the liquid crystal panel 20 includes an element substrate 60 having a TFT element as a switching element, and a counter substrate 30 facing the element substrate 60 and having color filters 37r, 37g, and 37b. I have. A retardation film 47 and a polarizing plate 49 are disposed on the outer surface (upper side in FIG. 2) of the counter substrate 30. Similarly, a retardation film 87 and a polarizing plate 89 are also arranged on the outer surface (lower side in FIG. 2) of the element substrate 60. The above-described lighting device (not shown) is disposed below the element substrate 60.

In the liquid crystal panel 20, the counter substrate 30 is formed on the color filters 37r, 37g, and 37b, and the color filters 37r, 37g, and 37b made of a plurality of colored layers having different hues with a substrate 31 such as glass as a base. The counter electrode 33 is formed, and an alignment film 45 formed on the counter electrode 33 is provided. Further, a transparent resin layer 41 is provided between the color filters 37r, 37g, and 37b and the counter electrode 33 to optimize the retardation of each of the reflective region and the transmissive region.
Here, the counter electrode 33 is a planar electrode formed on the entire area of the counter substrate 30 with ITO (indium tin oxide) or the like. The color filter includes a plurality of colored layers 37r, 37g, and 37b having hues of R (red), G (green), and B (blue), and pixels corresponding to the pixel electrode 63 on the element substrate 60 side facing each other. Each region is provided so as to exhibit light of a predetermined hue. A light shielding film 39 is provided corresponding to a region corresponding to the gap between the pixel regions.
Further, the alignment film 45 made of a polyimide-based polymer resin provided on the surface is subjected to a rubbing process as an alignment process.

Further, the element substrate 60 facing the counter substrate 30 is formed on a TFT element 69 as an active element functioning as a switching element, with a substrate 61 such as glass as a base, and a transparent insulating film 81 interposed therebetween. The pixel electrode 63 formed and an alignment film 85 formed on the pixel electrode 63 are provided.
Here, the pixel electrode 63 shown in FIG. 2 is formed as a light reflection film 79 (63a) for performing reflective display in the reflection region, and is formed as a transparent electrode 63b with ITO or the like in the transmission region. ing. The light reflecting film 79 as the pixel electrode 63a is formed of a light reflecting material such as Al (aluminum) or Ag (silver). However, the configuration of the pixel electrode and the light reflection film is not limited to the configuration as shown in FIG. 2, and the entire pixel electrode is formed using ITO or the like, and a reflection film using aluminum or the like as another member. It can also be set as the provided structure.
The alignment film 85 made of a polyimide-based polymer resin provided on the surface is subjected to a rubbing process as an alignment process.

The TFT element 69 includes a gate electrode 71 formed on the element substrate 60, a gate insulating film 72 formed on the entire area of the element substrate 60 on the gate electrode 71, and the gate insulating film 72 interposed therebetween. A semiconductor layer 70 formed above the gate electrode 71, a source electrode 73 formed on one side of the semiconductor layer 70 via a contact electrode 77, and a contact electrode 77 on the other side of the semiconductor layer 70. And a drain electrode 66 formed through the electrode.
The gate electrode 71 extends from the gate bus wiring (not shown), and the source electrode 73 extends from the source bus wiring (not shown). Further, a plurality of gate bus lines extend in the horizontal direction of the element substrate 60 and are formed in parallel in the vertical direction at equal intervals, and the source bus lines cross the gate bus lines with the gate insulating film 72 interposed therebetween. A plurality of lines extending in the vertical direction are formed in parallel in the horizontal direction at equal intervals.
Such a gate bus wiring is connected to a liquid crystal driving semiconductor element (not shown) and acts as, for example, a scanning line, while a source bus wiring is connected to another driving semiconductor element (not shown), for example, Acts as a signal line.
The pixel electrode 63 is formed in a region excluding a portion corresponding to the TFT element 69 in a rectangular region defined by the gate bus line and the source bus line intersecting each other. An area is configured.

Here, the gate bus wiring and the gate electrode can be formed of chromium, tantalum, or the like, for example. The gate insulating film is formed of, for example, silicon nitride (SiN _x ), silicon oxide (SiO _x ), or the like. Further, the semiconductor layer can be formed of, for example, doped a-Si, polycrystalline silicon, CdSe, or the like. Further, the contact electrode can be formed of, for example, a-Si, and the source electrode and the source bus wiring and the drain electrode integrated therewith can be formed of, for example, titanium, molybdenum, aluminum, or the like.

The organic insulating film 81 is formed over the entire area of the element substrate 60 so as to cover the gate bus lines, the source bus lines, and the TFT elements. However, a contact hole 83 is formed in a portion corresponding to the drain electrode 66 of the organic insulating film 81, and the pixel electrode 63 and the drain electrode 66 of the TFT element 69 are electrically connected at the contact hole 83.
In addition, in the organic insulating film 81, a resin film having a concavo-convex pattern composed of a regular or irregular repetitive pattern of peaks and valleys is formed as a scattering shape in a region corresponding to the reflective region R. Has been. As a result, the light reflection film 79 (63a) laminated on the organic insulating film 81 also has a light reflection pattern composed of an uneven pattern. However, this uneven pattern is not formed in the transmission region T.

In the liquid crystal panel having the above-described structure, external light such as sunlight and indoor illumination light enters the liquid crystal panel 20 from the counter substrate 30 side, and passes through the color filter 37 and the liquid crystal material 21 to reflect light. The film 79 reaches the film 79, is reflected there, and again passes through the liquid crystal material 21 and the color filters 37r, 37g, 37b, etc., and exits from the liquid crystal panel 20 to perform reflection display. On the other hand, the illuminating device is turned on, and light emitted from the illuminating device enters the liquid crystal panel 20 and passes through the translucent transparent electrode 63b and passes through the color filters 37r, 37g, 37b, the liquid crystal material 21, and the like. Then, by going out of the liquid crystal panel 20, transmissive display is performed.
Then, the light emitted from each pixel region is mixed and visually recognized, and various color displays are recognized as a color image as the entire display region.

3. Next, the flexible circuit board mounting structure electrically connected to the element substrate constituting the liquid crystal panel will be described in detail. 3 to 5 are diagrams for explaining the mounting structure of the flexible circuit board 93. FIG. 3A is a plan view of the substrate overhanging portion 60T of the element substrate 60 viewed from the mounting surface side of the flexible circuit board 93, and FIG. 3B is electrically connected to the element substrate 60. It is a top view of the flexible circuit board 93 made. 4 is an exploded view of the element substrate 60, the flexible circuit board 93, the semiconductor element 91, the anisotropic conductive film (ACF) 100, and the insulating adhesive film (hereinafter referred to as “NCF”) 110. FIG. 5A and 5B are cross-sectional views of the mounting structure of the flexible circuit board 93, and FIG. 5A shows the XX cross-section in FIG. 1 (the ZZ cross-section in FIG. 5B). FIG. 5B shows a cross-sectional view of the YY cross section in FIG. 1 viewed in the direction of the arrow.

As shown in these drawings, the flexible circuit board 93 includes a wiring pattern 123 made of Cu or the like on a flexible substrate 121 made of polyimide or the like, and an insulating film 125 (FIG. 5B) on the surface. Reference) is formed and configured. Further, a portion corresponding to the end portion of the wiring pattern 123 in the insulating film 125 is exposed and configured as an electrode terminal 127 electrically connected to the external connection terminal portion 19 on the element substrate 60 side. The pitch interval of the electrode terminals 127 is, for example, 40 μm or less in CtoC, and is formed corresponding to the size and arrangement of the external connection terminal portions 19 formed of the stud bumps 130 on the element substrate 60.

  The semiconductor element 91 includes bump portions 96 and 97 that are electrically connected to the terminal portions 14 and 18 on the element substrate 60 side. Each of these bump portions 96 and 97 includes an output side bump portion 97 that outputs a signal to the gate bus wiring 65 and the source bus wiring 66 and an input side bump portion 96 that receives a drive signal from a CPU (not shown). (See FIG. 3A). The semiconductor element 91 used in the present embodiment is mounted on the glass substrate 61 using the ACF 100, and the conductive particles 102 included in the ACF 100 are crushed by all the bump portions 96 and 97 to secure a mutual contact area. As shown, the heights of all the bump portions 96 and 97 are equal. These bump portions 96 and 97 are configured as rectangular bump portions in which the surface of the metal layer is plated with gold.

  On the other hand, one end side of the gate bus wiring 65 and the source bus wiring 66 in the display area A is extended to the substrate overhanging portion 60T of the element substrate 60. 14 is formed. These terminal portions 14 are electrically connected to the output-side bump portions 97 of the semiconductor element 91 so that a drive signal from the semiconductor element 91 is output. Further, on the side farther from the display area A than the terminal portion 14, the terminal portion 18 to which the input side bump portion 96 of the semiconductor element 91 is electrically connected and the external connection to which the flexible circuit board 93 is electrically connected. A terminal portion 19 is formed. The terminal portion 18 and the external connection terminal portion 19 are electrically connected by a connection wiring 67.

  In the substrate overhanging portion 60T, the gate bus wiring 65, the source bus wiring 66, and the connection wiring 67 are covered with an insulating film 94, and portions corresponding to the terminal portions 14, 18, and 19 in the insulating film 94 are covered. Openings 94a and 94b are formed in the case (see FIG. 5). A conductive film 22 made of corrosion-resistant ITO is formed in the opening 94a of the insulating film 94 so that the metal material constituting the gate bus wiring 65 and the like does not corrode.

  Here, in the liquid crystal device of the present embodiment, the ACF 100 is used for mounting the semiconductor element 91, and the bump portions 96 and 97 of the semiconductor element 91 and the terminal portions 14 and 18 of the element substrate 60 contain conductive particles 102. Therefore, the conductive film 22 is the terminal portions 14 and 18. On the other hand, NCF110 is used for mounting the flexible circuit board 93, and the stud bumps 130 are formed on the conductive film 22 as the external connection terminal portions 19 to which the electrode terminals 127 of the flexible circuit board 93 are electrically connected. Is formed.

  The stud bump is a bump formed by a wire bonding method. For example, a wire made of a conductive material such as Au with respect to a pad made of Au (gold) provided at a position where the stud bump is to be formed. The frictional heat is generated at the interface between the wire and the pad by pressing and applying ultrasonic waves, and the wire tip is melted and welded to the pad, and then the wire is torn.

The external connection terminal portion 19 including the stud bump 130 is disposed along the end side of the element substrate 60. The planar shape of the stud bump 130 is, for example, a circle having a diameter of 15 to 20 μm, and the pitch interval is set to 40 μm or less at CtoC corresponding to the electrode terminal 127 on the flexible circuit board 93 side described above. Yes.
Note that the stud bump 130 may be formed directly on the connection wiring 67 by omitting the conductive film 22.

  In the mounting structure of the flexible circuit board 93, the external connection terminals 19 on the element board 60 side are used as the stud bumps 130, and the element board 60 and the flexible circuit board 93 are bonded with the NCF 110, thereby improving the electrical connection reliability. Even when the pitch interval between the external connection terminal portion 19 on the element substrate 60 and the electrode terminal 127 on the flexible circuit board 93 is reduced, the element substrate 60 side and the flexible circuit board 93 are not reduced. The possibility of a short circuit between the adjacent terminal portions 19 and 127 on the side can be reduced.

That is, in the case of a mounting method using ACF, both terminals are used to electrically connect the external connection terminal on the element substrate and the electrode terminal on the flexible circuit board via the conductive particles contained in the ACF. It is necessary to secure the area of each terminal portion so that the conductive particles are arranged between the portions. Moreover, since there exists a possibility of the short circuit between terminal parts by a continuous conductive particle, there also exists a limit in reducing the pitch space | interval between terminal parts.
On the other hand, if there is a mounting method using stud bumps and NCFs, there is no risk of a short circuit due to conductive particles, and the electrical connection point is also determined by the position of the protrusions of the stud bumps. Can also be made relatively small. Therefore, it is possible to reduce the pitch interval between the terminal portions while reducing the short circuit between the adjacent terminal portions.

Further, since the protrusion 131 of the stud bump 130 on the element substrate 60 side is fixed in a state of being bitten into the electrode terminal 127 on the flexible circuit board 93 side, the electrical connection reliability is improved. In particular, in the present invention, since one substrate is the flexible circuit board 93, as shown in FIG. 6, there is a variation in the tip position of the protrusion 131 of the stud bump 130 (the height of the stud bump 130). However, since it can be bent according to the tip position of the protrusion 131 of the stud bump 130, it can be connected more reliably.
Therefore, even when the external shape of the liquid crystal device or the flexible circuit board is reduced and the pitch interval between the terminal portions is reduced, the connection reliability can be improved while reducing the short circuit between the adjacent terminal portions. .

  Further, as described above, since the plane area of the stud bump 130 can be made smaller than the area of the conventional terminal portion, the external connection terminal portion made of the stud bump 130 as in the liquid crystal device of the present embodiment. When 19 is arranged along the edge of the substrate 61, the length of the element substrate in the direction orthogonal to the arrangement direction of the external connection terminal portions 19 can also be shortened.

The shape of the stud bump as the external connection terminal can be configured, for example, as shown in FIGS. FIG. 7A shows an example of a stud bump 130 a in which a relatively long protrusion 131 is formed at the center of the pedestal 133, and FIG. 7B shows a relatively short protrusion 131 at the center of the pedestal 133. 7C is an example of a stud bump 130c in which a ladder-shaped convex portion 131 is formed on a pedestal 133, and FIG. 7D is a diagram of the pedestal 130b. This is an example of a stud bump 130 d in which a convex part 131 on the table is further formed on the part 133.
These exemplified stud bumps can be formed by a known method.

In the liquid crystal device of the present embodiment, NCF 110 made of a photo-curable resin material is used as NCF 110 for fixing flexible circuit board 93 to element substrate 60. Therefore, at the time of manufacturing, when mounting the flexible circuit board 93 after mounting the semiconductor element 91, it is not necessary to perform a curing operation by heating, and the possibility that the semiconductor element 91 is damaged by heat can be reduced. .
In this embodiment, NCF110 is used as the insulating adhesive, but the present invention is not limited to this, and in an electrically connected state between the insulating adhesive paste (NCP) and the flexible circuit board and the element board. An underfill or the like in which an adhesive is poured between them may be used. Typical examples of the resin constituting such an insulating adhesive include an epoxy resin and an acrylic resin.

4). The present invention is not limited to the configuration of the semiconductor element mounting structure described so far, and various modifications can be made.
For example, in the above-described configuration example, the external connection terminal portions on the element substrate made of stud bumps are arranged in a line along the edge of the substrate. As shown in FIG. 130 can also be arranged in a staggered pattern. In the example of FIG. 8A, the pitch interval w1 between the adjacent stud bumps 130 is made smaller than the pitch interval w2 when arranged in a straight line as shown in FIG. The size of the gap between the 130 is smaller than the width of the stud bump 130. Therefore, when the stud bumps 130 are arranged in a staggered manner as described above, the pitch interval between the terminal portions can be further reduced without short-circuiting the terminal portions.

Further, as shown in FIG. 9, a plurality of studs are arranged in the direction in which the flexible circuit board 93 is led out from the element substrate 60, that is, in the direction in which the connection wiring 67 of the element substrate 60 and the wiring pattern 123 of the flexible circuit board 93 extend. The bumps 130 </ b> A and 130 </ b> B may be formed, and a plurality of stud bumps 130 </ b> A and 130 </ b> B may be brought into contact with the electrode terminals 127 on the flexible circuit board 93 to be electrically connected. In the example of FIG. 9, two stud bumps 130 </ b> A and 130 </ b> B on the element substrate 60 are brought into contact with one electrode terminal 127 of the flexible circuit board 93.
Thus, the connection reliability can be further improved by electrically connecting the electrode terminal 127 on the flexible circuit board 93 side and the external connection terminal 19 on the element board 60 side at a plurality of locations. Also, as described above, the planar shape of the stud bumps 130A and 130B can be made relatively small, and the plurality of stud bumps 130A and 130B contacting the common electrode terminal may be connected. Even if it is formed, the outer shape of the substrate 61 is not significantly increased.

In the examples described so far, the external connection terminal portion on the element substrate is a stud bump and the terminal portion on the flexible circuit board is an electrode terminal. However, as shown in FIG. The upper external connection terminal portion 19 is the terminal portion 19 made of the conductive film 22 similarly to the terminal portion 18 to which the bump portion 96 of the semiconductor element 91 is electrically connected, and the terminal portion 127 on the flexible circuit board 93 side is used. A stud bump 140 may also be used.
Furthermore, as shown in FIG. 11, stud bumps 130 and 140 are formed at the end positions of the connection wiring 67 on the element substrate 60 and the wiring pattern 123 on the flexible circuit board 93, and the stud bumps 130 and 140 of each other are formed. The stud bumps 130 and 140 are brought into contact with and fixed to the opposing connection wiring 67 and the wiring pattern 123 in a state where they are shifted along the extending direction of the connection wiring 67 and the wiring pattern 123 so that the positions of the connection wiring 67 and the wiring pattern 123 do not overlap. You can also

[Second Embodiment]
As a second embodiment according to the present invention, an electronic apparatus including the liquid crystal device according to the first embodiment will be specifically described.

FIG. 12 is a schematic configuration diagram showing the overall configuration of the electronic apparatus of the present embodiment. The electronic apparatus includes a liquid crystal panel 20 provided in the liquid crystal device and a control unit 200 for controlling the liquid crystal panel 20. In FIG. 12, the liquid crystal panel 20 is conceptually divided into a panel structure 20a and a drive circuit 20b composed of a semiconductor element (IC) or the like. The control means 200 preferably includes a display information output source 201, a display processing circuit 202, a power supply circuit 203, and a timing generator 204.
The display information output source 201 includes a memory composed of a ROM (Read Only Memory), a RAM (Random Access Memory), etc., a storage unit composed of a magnetic recording disk, an optical recording disk, etc., and a tuning that outputs a digital image signal in a synchronized manner. It is preferable that the display information is supplied to the display processing circuit 202 in the form of an image signal or the like of a predetermined format based on various clock signals generated by the timing generator 204.

The display processing circuit 202 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 display the image. Information is preferably supplied to the driving circuit 20b together with the clock signal CLK. Furthermore, the drive circuit 20b preferably includes a first electrode drive circuit, a second electrode drive circuit, and an inspection circuit. Further, the power supply circuit 203 has a function of supplying a predetermined voltage to each of the above-described components.
If the electronic device according to the present embodiment includes a semiconductor element mounting structure in which the planar projection areas of the bump portions are different so as to satisfy a predetermined relationship, an electronic device with less conduction failure of the semiconductor element and can do.

  According to the present invention, it is possible to provide an electro-optical device and an electronic apparatus that have a semiconductor device with few conduction defects by including a semiconductor element mounting structure in which the planar projection areas of the bump portions are different so as to satisfy a predetermined relationship. be able to. Therefore, electro-optical devices and electronic devices such as liquid crystal devices and electroluminescence devices, such as mobile phones and personal computers, liquid crystal televisions, viewfinder type / monitor direct view type video tape recorders, car navigation devices, pagers, Electrophoresis devices, electronic notebooks, calculators, word processors, workstations, videophones, POS terminals, electronic devices with touch panels, devices with electron-emitting devices (FED: Field Emission Display and SCEED: Surface-Conduction Electron-Emitter Display) ) And so on.

1 is a schematic perspective view of a liquid crystal device according to a first embodiment. It is a schematic sectional drawing of the pixel area | region part of the liquid crystal device concerning 1st Embodiment. It is a top view of an element substrate and a flexible circuit board used for the liquid crystal device of a 1st embodiment. It is an exploded view for demonstrating the structure of the mounting structure of a flexible circuit board. It is sectional drawing for demonstrating the structure of the mounting structure of a flexible circuit board. It is a figure which shows the state from which the height of a stud bump differed. It is a figure which shows the example of the shape of a stud bump. It is a figure which shows the example which has arrange | positioned the stud bump in zigzag form. It is a figure which shows the state which formed the several stud bump with respect to one electrode terminal. It is a figure which shows the modification which formed the stud bump in the flexible circuit board side. It is a figure which shows the modification which formed the stud bump in both the element substrate and the flexible circuit board. It is a block diagram which shows schematic structure of the electronic device of 2nd Embodiment. It is a figure which shows the structure of the mounting structure of the conventional flexible circuit board.

Explanation of symbols

10: liquid crystal device (electro-optical device), 14: wiring terminal portion, 18: terminal portion, 19: terminal portion for external connection, 20: liquid crystal panel, 21: liquid crystal material, 22: conductive film, 23: sealing material, 26 : Semiconductor mounting region, 30: Color filter substrate, 31: Glass substrate, 33: Planar electrode (counter electrode), 37: Colored layer, 41: Resin layer, 45: Alignment film, 60: Element substrate (for electro-optical device) Substrate), 60T: substrate overhanging part, 61: glass substrate, 63: pixel electrode, 65: gate bus wiring, 66: source bus wiring, 67: connection wiring, 69: TFT element, 85: alignment film, 91: semiconductor Element: 93: Flexible circuit board, 94: Insulating film, 94a: Opening part, 96: Input side bump part, 97: Output side bump part, 100: ACF (anisotropic conductive film), 101: Adhesive, 102: Conductive particles, 1 0: NCF (insulating adhesive film), 121: flexible substrate, 123: wiring pattern 125: insulating film, 127: electrode terminals 130 - 140: Stud bumps

Claims (8)

In an electro-optical device including a substrate to which a flexible circuit board is electrically connected,
The substrate includes a first terminal portion, the flexible circuit board includes a second terminal portion,
At least one of the first terminal portion and the second terminal portion is a stud bump, and the flexible circuit is in a state where the first terminal portion and the second terminal portion are electrically connected. An electro-optical device, wherein the substrate and the substrate are fixed with an insulating adhesive.   The electro-optical device according to claim 1, wherein the stud bumps are arranged in a staggered manner.   At least one of the first terminal portion or the second terminal portion includes a plurality of stud bumps arranged in a direction in which the flexible circuit board is led out from the substrate, and the plurality of stud bumps The electro-optical device according to claim 1, wherein the other terminal portion is electrically connected at a plurality of locations.   The electro-optical device according to claim 1, wherein the first terminal portion is disposed along an edge of the substrate.   The electro-optical device according to claim 1, wherein the insulating adhesive is an insulating adhesive film, an insulating adhesive paste, or an underfill.   6. The semiconductor element is mounted on the substrate using an anisotropic conductive adhesive, and the insulating adhesive is a photo-curable adhesive. The electro-optical device according to 1. In a flexible circuit board mounting structure in which a flexible circuit board is mounted on a board,
The substrate includes a first terminal portion, the flexible circuit board includes a second terminal portion,
At least one of the first terminal portion and the second terminal portion is a stud bump, and the flexible circuit is in a state where the first terminal portion and the second terminal portion are electrically connected. A mounting structure for a flexible circuit board, wherein the board and the board are fixed with an insulating adhesive.   An electronic apparatus comprising the electro-optical device according to claim 1.

Images