JP2011175215A - Display device and method for manufacturing the display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems of absence of a means for directly measuring density of conductive particles included in an anisotropic conductive film and absence of a means for knowing particle density variations of the anisotropic conductive film. <P>SOLUTION: A wiring-inhibited region 10 is arranged in the active side of an IC chip 1, and a transparent see-through region 3 is arranged so as to cope with the wiring-inhibited region, in the transparent substrate 9 of a display element mounted with the IC chip 1. By measuring the number of conductive particles 7 placed on the wiring region through the see-through region 3, the density of conductive particles included in the anisotropic conductive film can be inspected. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a connection structure of a wiring portion of a display device including a liquid crystal display device, and more particularly to a connection technique between a transparent substrate and an electronic component.

  As a display having a high response speed such as high image quality, high definition, wide viewing angle range, and moving image, a TFT type liquid crystal display device using a liquid crystal display element having a switching element for selectively driving pixel by pixel is known.

  In a liquid crystal display element constituting a TFT type liquid crystal display device, a liquid crystal layer is sandwiched between a substrate made of glass and a counter substrate, and arranged in parallel in the y direction on the surface of the substrate on the liquid crystal layer side. A gate line (scanning signal line) and a source line (data line) that are insulated from the gate line and arranged in parallel in the x direction are formed. Each region surrounded by the gate line and the source line becomes a pixel region, and a TFT and a transparent pixel electrode are formed as switching elements in the pixel region. When the scanning signal is supplied to the gate line, the TFT is turned on, and a signal from the source line is supplied to the pixel electrode through the turned-on TFT. Signals are input from the driving IC chip (semiconductor circuit) to these gate lines and source lines (see, for example, Patent Document 1).

  Conventionally, an anisotropic conductive film (ACF) has been widely used to connect an IC chip and a wiring board. The anisotropic conductive film has a thermosetting resin as a binder, and when the connection terminal continues to be heated and pressurized with the conductive particles sandwiched between them, the thermosetting resin is polymerized and anisotropic conductive. The film is cured. The connection terminals are electrically connected by the conductive particles, and the connection terminals are fixed by a cured anisotropic conductive film (see, for example, Patent Document 2). FIG. 6 shows the anisotropic conductive film connecting portion seen through from the lower substrate side.

JP-A-2006-339613 (FIGS. 1 and 2) Japanese Patent Laying-Open No. 2005-200521 (FIG. 5)

  However, when the anisotropic conductive film is heated and pressurized, the conductive particles flow out of the adherend together with the softened binder first, so the amount of conductive particles between the connection terminals to be connected is reduced, The connection terminals may not be connected by the conductive particles. The shortage of the amount of conductive particles also occurs when the number of conductive particles contained in the original anisotropic conductive film is small or the density of the conductive particles varies. Conventionally, the number of conductive particles on the connection terminal has been measured, but there has been no means for directly measuring the density of conductive particles contained in the anisotropic conductive film. Even if there were variations in the density of the conductive particles contained in the anisotropic conductive film, it was not understood.

  A wiring prohibited area where a wiring pattern is not formed is provided on the active surface of the IC chip. In addition, a transparent region in which an opaque metal electrode is not provided is provided in a region corresponding to the wiring prohibition region of the IC chip on the substrate side of the display element. Thus, a structure in which the particle distribution and the number of particles of the conductive particles existing in the wiring prohibited area of the IC chip can be measured from the substrate side of the display element through the perspective area.

The see-through area is provided so as to be larger in size than the wiring prohibited area.
Furthermore, the size of the wiring prohibited area may be 0.01 mm square to 0.1 mm square, and the fluoroscopic area may be provided so that the difference in dimension from the wiring prohibited area is 0.006 mm to 0.01 mm.

  When the number of conductive particles varies or decreases, it can be confirmed on the actual product. In-line automatic inspection can be performed in the manufacturing process.

It is a schematic diagram for demonstrating the display apparatus of this invention. It is a schematic diagram showing the cross section of the display apparatus of this invention. It is the schematic diagram which expanded a part of display apparatus of this invention. It is a schematic diagram which shows a part of display apparatus of this invention. It is a schematic diagram which shows a part of display apparatus of this invention. It is a schematic diagram for demonstrating the conventional display apparatus.

  In the present invention, an IC chip is connected to a transparent substrate of a display element by an anisotropic conductive film, and a wiring prohibited region is provided on the active surface of the IC chip. A transparent region is provided on the transparent substrate so as to correspond to the wiring prohibited region. In this see-through region, opaque metal terminals and wirings are not arranged. Therefore, the conductive particles arranged in the wiring prohibited area can be seen through the fluoroscopic area. Then, by counting the conductive particles, the density of the conductive particles contained in the anisotropic conductive film can be measured.

The see-through area is provided so as to be larger in size than the wiring prohibited area.
In addition, the manufacturing method of the display device of the present invention prepares an IC chip provided with a wiring prohibited area and a transparent substrate provided with a transparent area corresponding to the wiring prohibited area. They are connected by an anisotropic conductive film. And the conductive particle contained in the anisotropic conductive film provided in the wiring prohibition area | region through the fluoroscope area | region is counted, and the conductive particle density of an anisotropic conductive film is measured.

Hereinafter, the configuration of the display device of the present invention will be described with reference to FIGS.
FIG. 2 is a cross-sectional view schematically showing the display device of the present invention. As shown in the drawing, in the display device of the present invention, a liquid crystal layer (not shown) is sandwiched between an upper substrate 8 and a lower substrate 9. The IC chip 1 is connected to the lower substrate 9 of the liquid crystal display element by an anisotropic conductive film 5. Connection terminals (hereinafter referred to as bumps) 6 of the IC chip 1 and the electrode pads 2 on the lower substrate 9 are electrically connected by conductive particles 7 included in the anisotropic conductive film 5.

  FIG. 1 shows a state in which the connection portion of the display device of the present invention is observed through the lower substrate side. The electrode pad 2 is aligned at a position corresponding to the bump on the IC chip 1 (hidden from the electrode pad 2 and cannot be seen), and the wiring 4 is drawn from the electrode pad 2. A wiring prohibited area 10 in which no wiring is formed is provided on the active surface on the IC chip 1.

  Here, the configuration of the IC chip 1 will be described with reference to FIG. Bumps 6 for connecting to the electrode pads on the lower substrate are arranged at both ends of the IC chip 1. Further, a wiring prohibition region 10 where no wiring or the like is formed is provided at the center.

  Next, the configuration of the connection region of the lower substrate 9 with the IC chip 1 will be described with reference to FIG. The lower substrate 9 is provided with electrode pads 2 connected to the bumps 6 of the IC chip 1, and the wiring 4 is drawn out from the electrode pads 2. The electrode pad 2 and the wiring 4 are formed from an opaque metal thin film. Further, when the IC chip is connected, the see-through region 3 is provided at a position corresponding to the wiring prohibited region 10. This portion is transparent because an opaque metal electrode is not provided.

  FIG. 3 is an enlarged schematic view of a part of FIG. Conductive particles 7 of the anisotropic conductive film 5 are dispersed on the IC chip 1. The state on the IC chip 1 can be confirmed through the transparent region 3 of the lower substrate 9, and the conductive particles 7 on the wiring prohibited region 10 can be counted.

  Hereinafter, the display device and the method for manufacturing the display device of the present invention will be specifically described with reference to examples.

  The structure of the display device of this embodiment will be described with reference to FIG. In this embodiment, the upper substrate 8 and the lower substrate 9 of the liquid crystal display element are each composed of a glass substrate having a thickness of 0.25 mm. The IC chip 1 has a size of 20 mm × 0.8 mm × 0.28 mm. The anisotropic conductive film 5 is set to a size that is slightly larger than the size of the IC chip 1 in consideration of the ease of alignment when pasted to the lower substrate 9 and the member cost. In this embodiment, an anisotropic conductive film 5 of 22 mm × 1.2 mm × 0.02 mm is used. The size of the bump 6 of the IC chip is 0.015 mm × 0.1 mm, and its height is 0.012 mm. The electrode pads 2 of the lower substrate 9 are about 0.002 mm larger than the end portions of the bumps 6 in consideration of the ease of alignment between the IC chip 1 and the lower substrate 9 to be 0.019 mm × 0.104 mm. .

  Further, as shown in FIG. 4, a wiring prohibited area 10 is provided on the IC chip 1. The wiring prohibition region 10 may be formed of a passivation film, a metal film, or a semiconductor film such as silicon or gallium arsenide constituting an IC chip. This size is preferably 0.01 mm × 0.01 mm to 0.1 mm × 0.1 mm. More desirably, 0.02 mm × 0.02 mm to 0.05 mm to 0.05 mm is preferable. If the wiring prohibition area 10 is large, the IC chip 1 becomes large and the cost increases. On the contrary, when the wiring prohibited area 10 is small, the counting accuracy of the conductive particles 7 is lowered. In this embodiment, the size of the wiring prohibited area 10 is set to 0.03 mm × 0.03 mm.

  Further, as shown in FIG. 5, a see-through region 3 is provided on the lower substrate 9 of the liquid crystal display element. The transparent region 3 may be transparent, and a transparent electrode may be formed on the lower substrate made of glass. The size of the see-through area 3 is 0.003 mm to 0.005 mm from the end of the wiring prohibited area 10 on the IC chip in consideration of the deviation in the alignment between the IC chip 1 and the lower substrate 9. The dimension is increased by about 0.006 mm to 0.01 mm. In the present embodiment, the size of the transparent region 3 is 0.038 mm × 0.038 mm. An anisotropic conductive film having an average diameter of conductive particles of 0.0035 mm and an area density of the conductive particles of 50,000 per square mm is used.

  As described above, the IC chip 1 provided with the wiring prohibited area 10 is connected to the lower substrate 9 provided with the transparent area 3 by the anisotropic conductive film 5, so that the conductive particles 7 on the wiring prohibited 10 pass through the transparent area 3. Can be counted.

  Further, in the display device manufacturing method of this embodiment, after preparing the IC chip 1 provided with the wiring prohibited area 10 and the lower substrate 9 provided with the fluoroscopic area 3 as described above, the IC chip 1 is anisotropically prepared. The conductive film 5 is used to connect to the lower substrate 9 by heating and pressing. After the connection, the wiring prohibited area 10 is observed with a microscope from the lower substrate 9 side, and the number of conductive particles 7 in the wiring prohibited area 10 is counted. By comparing and verifying this measured value with the number of conductive particles of the sample measured in advance and the standard deviation of the number of conductive particles, abnormal distribution of conductive particles in the anisotropic conductive film or different density of conductive particles was found. The misuse of the anisotropic conductive film can be confirmed. In this example, the average number of conductive particles was 45 and the standard deviation was 8.

  In the present embodiment, the sizes of the parts constituting the display device are different from those in the first embodiment. The basic configuration of the other display devices is the same.

  In this embodiment, the upper substrate 8 and the lower substrate 9 of the liquid crystal display element are each composed of a glass substrate having a thickness of 0.3 mm. The IC chip 1 has a size of 19.95 mm × 1.27 mm × 0.33 mm. The anisotropic conductive film 5 has a size that is slightly larger than the size of the IC chip 1 in consideration of ease of alignment at the time of bonding and member cost. In this embodiment, an anisotropic conductive film of 22 mm × 2.0 mm × 0.02 mm is used. The bump 6 of the IC chip has a size of 0.03 mm × 0.067 mm and a height of 0.015 mm. The electrode pads 2 of the lower substrate 9 are about 0.002 mm larger from the end portions of the bumps 6 in consideration of the ease of alignment between the IC chip 1 and the lower substrate 9, and are 0.034 mm × 0.071 mm. To do.

  As shown in FIG. 4, a wiring prohibited area 10 is provided on the IC chip 1. The wiring prohibition region 10 may be formed of a passivation film, a metal film, or a semiconductor film such as silicon or gallium arsenide constituting an IC chip. In this embodiment, the size of the wiring prohibited area 10 is set to 0.04 mm × 0.04 mm. Further, as shown in FIG. 5, a see-through region 3 is provided on the lower substrate 9 of the liquid crystal display element. In this embodiment, the size of the fluoroscopic region 3 is 0.05 mm × 0.05 mm. As the anisotropic conductive film, one having an average diameter of conductive particles of 0.004 mm and an area density of 30,000 particles per square mm is used.

  Thus, the IC chip 1 provided with the wiring prohibited area 10 is connected to the lower substrate 9 provided with the transparent area 3 by the anisotropic conductive film 5, so that the IC chip 1 on the wiring prohibited area 10 passes through the transparent area 3. The conductive particles 7 can be counted.

  Further, when the display device was manufactured by the same manufacturing method as in Example 1 and the wiring prohibited area 10 was observed with a microscope from the lower substrate 9 side after the IC chip 1 was connected, the conductive particles 7 in the wiring prohibited area 10 were observed. The average number of conductive particles was 27 and the standard deviation was 6.

  In each of the above-described embodiments, the display device having a liquid crystal display element has been described. However, the same configuration and manufacturing method can be used for a display device using an organic EL element, an inorganic EL element, or a plasma display element.

  Since it is possible to count the number of conductive particles, it is easy to find abnormalities in the manufacturing process. Since it can be applied to any display device including a transparent substrate, it can also be applied to a display device using an EL element or a plasma display element. Automatic inspection can also be performed in combination with image recognition technology.

1 IC chip 2 Electrode pad 3 Transparent region 4 Wiring 5 Anisotropic conductive film (ACF)
6 Bump 7 Conductive particle 8 Upper substrate 9 Lower substrate 10 Wiring prohibited area

Claims (4)

In a display device comprising a display element having a transparent substrate, and an IC chip connected to the transparent substrate by an anisotropic conductive film,
The IC chip is provided with a wiring prohibited area,
The transparent substrate is provided with a transparent see-through area corresponding to the wiring prohibited area,
The display device characterized in that the conductive particles contained in the anisotropic conductive film in the wiring prohibited region can be seen through the see-through region.   The display device according to claim 1, wherein the see-through area is larger than the wiring prohibition area.   The size of the wiring prohibited area is 0.01 mm square to 0.1 mm square, and a difference in dimension between the see-through area and the wiring prohibited area is 0.006 mm to 0.01 mm. The display device described in 1. In a manufacturing method of a display device in which an IC chip is connected to a transparent substrate of a display element by an anisotropic conductive film,
A first step of preparing the IC chip provided with a wiring prohibited area and the transparent substrate provided with a transparent see-through area corresponding to the wiring prohibited area;
A second step of connecting the IC chip to the transparent substrate by the anisotropic conductive film;
And a third step of measuring the conductive particle density of the anisotropic conductive film on the wiring prohibited region through the transparent region.

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