JPH0933940A - Mount structure for semiconductor chip for driving display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve connection reliability by reducing a cross phenomenon by the reduction of input resistance and preventing a connection part from being broken by the reinforcement of an auxiliary substrate. SOLUTION: The mount structure consists of an FPC 5 which has metal, wiring, a display panel substrate 1 which has a display driving connection electrode, a semiconductor chip 7 which has an input projection electrode 8 and an output projection electrode 9 adhered to the metal wiring 6 and display driving connection wiring with conductive adhesives 10 over both the FPC 5 and display panel substrate 1, and an auxiliary substrate 3 which is backed over both the FPC 5 and display panel substrate 1 and reinforces the abutting parts of both. Then the auxiliary substrate 3 has an upper-stage part and a lower-stage part which are different in height because of a step; and the metal wiring 6 is adhered and fixed to the upper-stage part and the display driving connection electrode 2 is adhered and fixed to the lower stage part so that the both are almost in level with each other.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a liquid crystal display, an electroluminescence (EL) display, a light emitting diode (LED).
Regarding a connection structure between a display panel substrate such as a display and a semiconductor chip, in particular, a flexible printed substrate (hereinafter referred to as FPC) is used, and the semiconductor chip is directly connected to the display panel substrate by a COG method (Chip On Glass). Regarding mounting structure.

[0002]

2. Description of the Related Art As a conventional example for mounting a semiconductor chip on a display panel, a TAB method (Tape Automate) is used.
TC packaged by d Bonding)
There is a method of mounting P (Tape Carrier Package) on a display panel substrate. Further, there is a structure in which a semiconductor chip is directly connected to a display panel substrate by a COG method (Chip On Glass), and an FPC is mounted on wirings on the display panel substrate related to a power supply and an input signal.

However, when a connection pitch of 100 μm or less is required for the connection between the FPC and the display panel substrate, the COG method is used, which allows the semiconductor chip to be entirely mounted. The conventional COG method will be described below with reference to FIG. FIG. 6 shows a semiconductor chip 7 on the display panel substrate 1.
FIG. 3 is a schematic enlarged view showing a cross-sectional shape of a state in which the FPC5 and the FPC5 are connected using the COG method.

An input protruding electrode 8 and an output protruding electrode 9 are formed on a semiconductor chip 7 by using a metal such as copper or gold by a plating method or a vacuum evaporation method. Next, a conductive adhesive 10 in which conductive particles are mixed in an epoxy adhesive is applied to the tips of the input protruding electrode 8 and the output protruding electrode 9 by a printing method or a dipping method. After that, the semiconductor chip 7 and the display panel substrate 1 are aligned with each other by using a binocular microscope, and the display panel substrate 1 made of glass is aligned.
Display drive connection electrode 2 and input connection electrode 21 arranged in
The output projecting electrode 9 and the input projecting electrode 8 are connected to. The display drive connection electrode 2 and the input connection electrode 21
Is composed of a transparent conductive film such as indium tin oxide (hereinafter referred to as ITO).

Further, heat treatment is performed to cure the conductive adhesive 10. As a result, good electrical connection can be obtained between the output projecting electrode 9 and the display drive connecting electrode 2, and between the input projecting electrode 8 and the input connecting electrode 21. After that, an insulating resin 11 made of an organic material such as an epoxy resin is poured into a gap between the semiconductor chip 7 and the display panel substrate 1 and heat treatment is performed.
Cure. Next, the metal wiring 6 of the FPC 5 and the input connection electrode 21 of the display panel substrate 1 are aligned with each other, and an anisotropic conductive sheet in which conductive particles are mixed in a thermosetting resin sheet is used to form the outer periphery of the input connection electrode 21. The metal wiring 6 is connected to the FPC connection part corresponding to the part.

The resistance value of the metal wiring 6 of the FPC 5 mounted by the above method is as small as 1 ohm or less, but since the input connection electrode 21 is made of ITO having high resistance, the input resistance is tens of ohms or more. turn into. Therefore, the power supply voltage input to the semiconductor chip 7 is not stable, the power supply voltage fluctuates depending on the displayed image, and the crosstalk phenomenon that affects the display other than the display pattern is likely to occur.

In order to solve this problem, a method of directly bonding the input protruding electrode 8 of the semiconductor device 7 and the metal wiring 6 of the FPC 5 with the conductive adhesive 10 can be considered. An example thereof will be described below with reference to FIG. 7. Display drive connection electrode 2 and FPC 5 on display panel substrate 1 made of glass
The upper metal wiring 6 is aligned using a binocular microscope, and the display panel substrate 1 and the FPC 5 are bonded to each other via the adhesive 4. The adhesive 4 is a thermosetting epoxy adhesive or the like, and may be liquid or film-like. At this time, a step is formed between the surface of the display drive connection wiring 2 on the display panel substrate 1 and the surface of the metal wiring 6 on the FPC 5.

Next, the input projecting electrodes 8 and the output projecting electrodes 19 are formed on the semiconductor chip 7 by plating or the like using a metal such as copper or gold. At this time, the input protruding electrode 8 and the output protruding electrode 19
The height of the output projecting electrode 19 is made larger than the height of the input projecting electrode 8 so that there is a step. The step difference is formed so as to have the same value as the thickness of the FPC 5 having the metal wiring 6 and the thickness of the adhesive. Next, a conductive adhesive 10 in which conductive particles are mixed with an epoxy adhesive is applied to the tip ends of the input protruding electrode 8 and the output protruding electrode 19 by a printing method or a dipping method. After that, the display drive connection electrodes 2 arranged on the semiconductor chip 7 and the display panel substrate 1 using a binocular microscope.
Are aligned with the metal wiring 6 on the FPC, and the output projecting electrode 19 and the input projecting electrode 8 are connected to the display drive connection electrode 2 and the metal wiring 6, respectively. Further, heat treatment is performed to cure the conductive adhesive 10. As a result, good electrical connection can be obtained between the output protruding electrode 19, the display drive connecting electrode 2, the input protruding electrode 8 and the metal wiring 6.

According to the above method, the input resistance is reduced to several ohms or less. Therefore, the power supply voltage input to the semiconductor chip 7 is stabilized, and the crosstalk phenomenon of the display panel is improved. However, the height of the input protruding electrode 8 of the semiconductor chip 7 is 5 to 20 μm, and the height of the output protruding electrode 19 is 110 to 130 μm, which is extremely high. The output protruding electrode 19 can be processed, but it is not preferable in consideration of the stability as an electrode, the method of applying the conductive adhesive, and the mass productivity.

Therefore, a method in which the height of the output protruding electrode and the height of the input protruding electrode are made the same and the input protruding electrode 8 and the metal wiring 6 are directly bonded can be considered. An example thereof will be described below with reference to FIG. The input projecting electrodes 18 and the output projecting electrodes 9 are formed on the semiconductor chip 7 by using a metal such as copper or gold by a plating method or a vacuum deposition method. Next, the output projection electrode 9
A conductive adhesive 10 in which conductive particles are mixed with an epoxy-based adhesive is applied to the tip of the sheet by a printing method or a dipping method. After that, the display drive connection electrodes 2 of the display panel substrate 1 and the output projecting electrodes 9 provided on the semiconductor chip 7 are arranged so that the input projecting electrodes 18 are exposed to the outside of the display panel substrate 1 by using a binocular microscope. Align using. Subsequently, the semiconductor chip 7 is pressed to heat and cure the conductive adhesive 10 while it is temporarily connected to the display panel substrate 1.

Next, an insulating resin 11 made of an organic material such as epoxy or rubber is injected into the peripheral area of the output bump electrode 9 of the semiconductor chip 7 and then heated and cured. In this step, care should be taken so that the insulating resin 11 does not go around the input protruding electrode 18. Next, the anisotropically conductive sheet 12 is temporarily adhered to the FPC 5. Further, the semiconductor chip 7 is aligned downward with the metal wiring 6 of the FPC 5 and the input protruding electrode 18 of the semiconductor chip 7. Continued FPC5
The anisotropically conductive sheet 12 is thermocompression bonded from the side to bond the FPC 5 and the semiconductor chip 7 together. As a result, the metal wiring 6 and the input protruding electrode 18 are connected. Finally, although not shown, an epoxy resin or a rubber resin is formed around the FPC 5 and the semiconductor chip 7 to protect each connection portion. According to the above method, the height of the output protruding electrode 9 can be set to 5 to 20 μm. However, this mounting structure is also unfavorable in terms of mass productivity because there is a risk that the connecting portion will be damaged if an external force is applied during or after the manufacturing process.

[0012]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to directly connect the metal wiring of the FPC and the input projecting electrode of the semiconductor chip to the display panel when the semiconductor chip is mounted on the display panel by the COG method. It is to provide a mounting structure of a semiconductor chip that has high connection reliability by reinforcing the connection portion so as not to be damaged even when an external force is applied to it, and is excellent in mass productivity.

[0013]

In order to solve the above-mentioned problems, a mounting structure of a semiconductor chip for driving a display panel of the present invention has a flexible printed board having metal wiring and a peripheral portion which constitutes a part of the display panel. A display panel substrate having a display drive connection electrode, and an input projecting electrode and an output which are spread over both the flexible printed circuit board and the display panel substrate and are bonded to the metal wiring and the display drive connection wiring by a conductive adhesive respectively. A mounting structure comprising a semiconductor chip having a protruding electrode, and an auxiliary substrate which is lined across both the flexible printed substrate and the display panel substrate and reinforces the contact portion between the two,
The auxiliary substrate has an upper portion and a lower portion having different heights due to steps, and the former is bonded to the upper portion and the latter is bonded to the lower portion so that the metal wiring and the display drive connection electrode are arranged on substantially the same plane. It is characterized by being fixed.

[0014]

The display panel substrate having the display drive connection electrodes is adhered to the lower portion of the auxiliary substrate having the step formed by the upper portion and the lower portion, and then the FPC having the metal wiring is adhered to the upper portion. At this time, the step difference of the auxiliary substrate is set to the same value as the difference between the thickness of the display panel substrate and the thickness of the FPC so that the display drive connection electrode and the metal wiring are arranged on substantially the same plane. Next FP
The input projecting electrode and the output projecting electrode on the semiconductor chip are respectively connected to the metal wiring and the display drive connecting wiring across both C and the display panel substrate by a conductive adhesive. As a result, the metal wiring and the input projecting electrode are directly connected through the conductive adhesive to reduce the input connection resistance to the semiconductor chip and stabilize the input power supply voltage, thereby suppressing the crosstalk phenomenon. Furthermore, the auxiliary board is F
The mounting structure is such that it is lined across both the PC and the display panel substrate to reinforce the respective connection portions of the metal wiring, the input protruding electrode, the display drive connection wiring, and the output protruding electrode. As a result, it is possible to prevent damage to the connection portion even when an external force is erroneously applied during or after the semiconductor chip mounting process, and it is possible to improve connection reliability.

[0015]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic enlarged view showing a cross-sectional shape of a semiconductor chip mounting structure according to an embodiment of the present invention. FIG. 2 is a schematic enlarged view showing the cross-sectional shape of the auxiliary substrate in the embodiment of the present invention.
3 and 4 are schematic enlarged views showing the cross-sectional shape of the intermediate step of the method of mounting a semiconductor chip according to the embodiment of the present invention.
FIG. 5 is a schematic enlarged view showing the planar shape of the semiconductor chip mounting structure of the embodiment of the present invention.

Embodiments of the present invention will be described below by taking a semiconductor chip mounting structure in a liquid crystal display device as an example.
The auxiliary substrate 3 shown in FIG. 2 is made of a thermosetting epoxy resin and is formed by using a mold, and the upper stage portion 3
1 and the lower stage portion 32. Next, as shown in FIG. 3, the display panel substrate 1 made of glass and having the display drive connection electrodes 2 arranged on the periphery thereof is pressed onto the lower step portion 32 of the auxiliary substrate 3 with a heat tool through the adhesive agent 80. ~ 120 ° C
Then, the adhesive 4 was heated and cured to bond. The display drive connection electrode 2 is composed of a transparent conductive film such as ITO.

Next, as shown in FIG. 5, alignment is performed using the alignment marks 15 provided on the display panel substrate 1 and the FPC 5 which are adhered to the lower portion 32 of the auxiliary substrate 3, respectively. Continuing, as shown in FIG.
The FPC 5 is heated to 80 to 120 ° C. while pressing the FPC 5 via the adhesive 4 with a heat tool to cure and bond the adhesive 4. In this state, a step 33 is provided between the upper step portion 31 and the lower step portion 32 of the auxiliary substrate 3 so that the display drive connection electrode 2 and the metal wiring 6 are arranged substantially on the same plane. Step 3
The size of 3 may be equal to the difference in thickness between the display panel 1 and the FPC 5, but since it can be adjusted by the thickness of the adhesive 4, it is not necessary to strictly equalize the difference in thickness between the two.

Further, when the heat tool is used, the height of the metal wiring 6 of the FPC 5 and the display drive connecting electrode 2 of the display panel substrate 1 can be increased by contacting the display drive connecting electrode 2 of the display panel substrate 1 with the heat tool. It becomes easy to align. The width dimension of the upper step portion 31 of the auxiliary substrate 3 may be at least larger than the width of the input protruding electrode 8 on the semiconductor chip 7, and may be 0.1 mm to 5 mm. Further, the width dimension of the lower step portion 32 of the auxiliary substrate 3 may be at least larger than the width of the output projecting electrode 9 on the semiconductor chip 7, and may be a size that does not hang on the display panel constituent portion,
It may be 0.1 mm to 5 mm.

When the adhesive 4 is liquid, a dispenser is used to dispense an upper step 31 of the auxiliary substrate 3 and a lower step 3 of the auxiliary substrate 3.
2, and in the case of the film adhesive 4, the adhesive is cut out into a size corresponding to each and stuck. In any case, the adhesive 4 may be provided on the auxiliary substrate 3 or the FPC 5
It may be provided either on the display side or the display panel substrate 1 side. Further, as the adhesive 4, it is desirable to use plastic beads having a particle size for adjusting the adhesive thickness within plus or minus 10% and glass fibers mixed in 5 to 30 wt% in resin such as epoxy. This makes it easy to control the thickness of the adhesive 4.

Next, the input projecting electrode 8 and the output projecting electrode 9 are formed on the semiconductor chip 7 by using a metal such as copper or gold by a plating method or a vacuum deposition method. The shapes of the input protruding electrode 8 and the output protruding electrode 9 are preferably circular with a diameter of 50 to 200 μm. Next, a conductive adhesive 1 in which conductive particles are mixed with epoxy adhesive at the tips of the input protruding electrode 8 and the output protruding electrode 9
A fixed amount of 0 is applied by a printing method or a dipping method. Thereafter, as shown in FIG. 5, the display drive connection electrodes 2 arranged on the semiconductor chip 7 and the display panel substrate 1 and the metal wirings 6 on the FPC are aligned using a binocular microscope, and as shown in FIG. The output projection electrode 9 and the input projection electrode 8 are connected to the display drive connection electrode 2 and the metal wiring 6, respectively.
Then, heat treatment was performed at a temperature of 50 to 150 ° C. to cure the conductive adhesive 10. As a result, good electrical connection was obtained between the output projection electrode 9 and the display drive connection electrode 2, and between the input projection electrode 8 and the metal wiring 6. Finally, in the peripheral area of the FPC 5, the semiconductor chip 7, and the display panel substrate 1, an insulating resin 11 made of an organic material such as epoxy or rubber is used.
And then the insulating resin 11 is cured by heating.

In mounting a simple matrix type liquid crystal panel having a diagonal size of 4 inches, the signal electrode semiconductor chips are connected by the COG method, and the scanning electrode semiconductor chips are connected by the mounting structure of the present invention, resulting in crosstalk. A good display image with few defects was obtained, and the phenomenon that the connection part was damaged did not occur during mounting and after completion.

In the description of the embodiments of the present invention, the material of the auxiliary substrate 3 is an example in which a thermosetting epoxy resin is used. However, as long as it has appropriate rigidity and heat resistance of 200 ° C. or higher,
Metal, ceramic, plastic, etc. can be freely selected.
Further, in the description of the embodiments of the present invention, the mounting structure of the semiconductor chip is described as an example using a conductive adhesive, but instead of the conductive adhesive, a photocurable resin or an anisotropic conductive sheet or a conductive material is used. Even if the input projecting electrode 8 and the output projecting electrode of the semiconductor chip 7, the display drive connecting electrode 2 of the display panel substrate 1 and the metal wiring 6 of the FPC 5 are connected to each other using the conductive beads, the same result is obtained. Was given. When the photo-curable resin is used, the insulating resin 11 shown in FIG. 1 is unnecessary. Further, in FIG. 3, the lower part 32 of the auxiliary substrate 3 and the display panel substrate 1 are adhered to each other after the image display portion of the liquid crystal display panel is completed, but the process before the image display portion of the liquid crystal display panel is completed. In the above, after the display drive connection electrode 2 is formed on the display panel substrate 1, the lower part 32 of the auxiliary substrate 3 is formed.
May be adhered to.

[0023]

As described above, according to the present invention, C
The output projection electrode of the semiconductor chip and the display drive connection wiring of the display panel substrate, which is a feature of the OG method, can be connected with high density, and the input resistance to the semiconductor chip can be connected within a few ohms, and the input power supply voltage is stable. By doing so, the crosstalk phenomenon of the display device can be reduced. Further, the auxiliary substrate reinforces the connection portion, so that the connection portion can be prevented from being damaged even if an external force is erroneously applied during or after the semiconductor chip mounting process, and the connection reliability can be improved.

[Brief description of drawings]

FIG. 1 is a schematic enlarged view showing a cross-sectional shape of a semiconductor chip mounting structure according to an embodiment of the present invention.

FIG. 2 is a schematic enlarged view showing a cross-sectional shape of an auxiliary substrate in an example of the present invention.

FIG. 3 is a schematic enlarged view showing the cross-sectional shape of the mounting structure for explaining the connecting step in the example of the present invention.

FIG. 4 is a schematic enlarged view showing the cross-sectional shape of the mounting structure for explaining the connecting step in the example of the present invention.

FIG. 5 is a schematic enlarged view showing a planar shape of a semiconductor chip mounting structure according to an embodiment of the present invention.

FIG. 6 is a schematic enlarged view showing a cross-sectional shape of a semiconductor chip mounting structure in a conventional example.

FIG. 7 is a schematic enlarged view showing a cross-sectional shape of a semiconductor chip mounting structure in a conventional example.

FIG. 8 is a schematic enlarged view showing a cross-sectional shape of a semiconductor chip mounting structure in a conventional example.

[Explanation of symbols]

 1 Display Panel Substrate 2 Display Drive Connection Electrode 3 Auxiliary Substrate 4 Adhesive 5 Flexible Printed Board 6 Metal Wiring 7 Semiconductor Chip 8 Input Projection Electrode 9 Output Projection Electrode 10 Conductive Adhesive 11 Insulating Resin 12 Anisotropic Conductive Sheet 15 Positioning Mark 18 Input protruding electrode 19 Output protruding electrode 20 Display panel 21 Input connection electrode 31 Upper stage 32 Lower stage 33 Step

Claims (1)

[Claims] 1. A flexible printed circuit board having a metal wiring, a display panel circuit board which constitutes a part of a display panel and has a display drive connection electrode in a peripheral portion thereof, and the flexible printed circuit board and the display panel circuit board. A semiconductor chip having an input projecting electrode and an output projecting electrode, which are adhered to the metal wiring and the display drive connection wiring by a conductive adhesive, respectively, and both of them are lined with the flexible printed board and the display panel board. A mounting structure comprising an auxiliary substrate that reinforces the contact portion, wherein the auxiliary substrate has an upper step portion and a lower step portion having different heights due to steps, and the metal wiring and the display drive connection electrode are substantially in the same plane. A display panel characterized in that the former is adhered and fixed to the upper part and the latter is adhered to the lower part so that they are lined up. Drive semiconductor chip mounting structure.