JP2003295784A - Ic chip for driving liquid crystal, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To drive normally a liquid crystal display panel by preventing the occurrence of a crack in an IC chip for driving liquid crystal. <P>SOLUTION: A film 10 constituted of the same material as a passivation film 6 formed on a circuit forming plane of a silicon substrate 2 is formed on a plane of an opposite side to the circuit forming plane of the silicon substrate 2 so that the thickness is equal to or larger than the thickness of a passivation film 6 formed on the circuit forming plane of the silicon substrate 2. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a film of the same quality as a passivation film for protecting a formation circuit of an IC chip.
The present invention relates to a liquid crystal driving IC chip and a liquid crystal display device which are provided on the back surface of a C chip.

[0002]

2. Description of the Related Art Generally, in order to drive a liquid crystal display panel that constitutes a liquid crystal display device, for example, it is necessary to connect a liquid crystal driving IC chip to the liquid crystal display panel. By connecting the input terminal of the liquid crystal display panel and the output signal wiring from the liquid crystal driving IC chip, the liquid crystal display panel can be driven.

In recent years, the liquid crystal driving IC chip has been made thinner because the cutting time at the time of dicing can be shortened and the manufacturing cost can be reduced. A conventional example of this liquid crystal driving IC chip will be described below.

6 and 7 are cross-sectional views showing a conventional liquid crystal driving IC chip. As shown in FIG. 6, the liquid crystal driving IC chip 30 has a silicon substrate 31. Transistors (not shown) and the like are formed on the circuit formation surface of. In addition, the silicon substrate 31
A plurality of wirings 32 are formed on the circuit formation surface of
Each of these wirings 32 is extended to the end portion of the silicon substrate 31 and serves as an electrode terminal 33. Furthermore, in order to prevent the ions from entering the circuit forming surface of the silicon substrate 31 excluding the surface of each electrode terminal 33 and damaging the forming circuit of the IC chip, etc. A passivation film 34 is formed, and the passivation film 34 is mainly formed of silicon nitride (Si ₃ N
₄ ) consists of. In addition, each of the electrode terminals 3
Bumps 36 are formed on the surface of No. 3 via a barrier metal 35.

Next, as an example of a method of connecting the liquid crystal driving IC chip 30 and the external wiring, by using a flexible substrate as the external wiring, it is possible to adapt to a flexible mounting structure and to reduce the thickness of the liquid crystal display device. COF (Chip) from the past because of the reduction in weight and weight.
on Film) has been adopted. A flexible wiring board as an external wiring used for this COF has a film substrate, and a plurality of conductors are formed on one surface of the film substrate. The liquid crystal driving IC chip and the flexible wiring board are arranged via an adhesive material such as an epoxy resin, and are connected by applying heat and pressure to the adhesive material to cure it.

[0006]

However, the silicon substrate 31 and the passivation film 34 of the liquid crystal driving IC chip 30 have different thermal expansion coefficients, and as described above, the liquid crystal driving IC chip 30 has recently been made thinner. Since it is progressing, the liquid crystal driving IC chip 30 having the passivation film 34 formed on the circuit forming surface is warped such that the circuit forming surface becomes the inside when diced, as shown in FIG. . Furthermore, this liquid crystal driving IC
When the chip 30 is connected to the flexible wiring board, the connecting material used is contracted by being hardened by heat, so that the liquid crystal driving IC chip 30 is connected to the flexible wiring board on a circuit forming surface. Since a force is applied to the side, as shown in FIG.
The warp of the C chip 30 becomes even stronger.

Therefore, the liquid crystal driving IC chip 30 is used.
The passivation film 34 is cracked due to the extreme warpage of the liquid crystal, resulting in the liquid crystal driving IC chip 30.
Had a problem of impairing the function of.

Even if the passivation film 34 is not cracked, a force is applied to each element of the liquid crystal driving IC chip 30 by the extreme warpage of the liquid crystal driving IC chip 30. There is also the possibility of impairing its function. Further, since the liquid crystal driving IC chip 30 is always subjected to a force due to such a warp, it has a low impact resistance, and the passivation film 34 is easily cracked, and further, the liquid crystal driving IC chip 30. It was easy to crack itself.

Further, as a result of cracks or cracks in the liquid crystal driving IC chip 30, the liquid crystal display panel connected via the flexible wiring board cannot be driven normally.

The present invention has been made in view of these points, and it is possible to prevent the occurrence of cracks or breaks in the liquid crystal driving IC chip and to drive the liquid crystal display panel normally. An object is to provide a chip and a liquid crystal display device.

[0011]

In order to achieve the above object, the liquid crystal driving IC chip according to the present invention is a liquid crystal driving IC chip in which a passivation film is formed on a circuit formation surface. A film made of the same material as the passivation film formed on the circuit formation surface of the IC chip is formed on the back surface of the IC chip.

According to the invention described in claim 1, since the film of the same material as the passivation film is formed on the back surface of the liquid crystal driving IC chip, it is possible to suppress the warp of the liquid crystal driving IC chip. it can.

In a liquid crystal driving IC chip according to a second aspect of the present invention, the film thickness of the film formed on the back surface of the IC chip is the same as that of the passivation film formed on the circuit forming surface of the IC chip. It is characterized in that it is formed with a dimension thicker than the film thickness.

According to the second aspect of the present invention, since a film having a film thickness thicker than the passivation film formed on the circuit forming surface is formed on the back surface of the liquid crystal driving IC chip, the liquid crystal is formed. When the driving IC chip is diced, the liquid crystal driving IC chip is warped such that the back surface is inside. Then, when the liquid crystal driving IC chip is bonded to the flexible wiring substrate or the transparent electrode substrate using a thermosetting resin, a force is applied in the direction of the circuit forming surface of the liquid crystal driving IC chip. As a result, the liquid crystal driving IC chip becomes flat in the connected state.

Further, in a liquid crystal display device according to a third aspect of the present invention, a liquid crystal display panel in which liquid crystal is sealed in a gap between a pair of transparent substrates and a liquid crystal in which a passivation film is formed on a circuit formation surface. In a liquid crystal display device having a driving IC chip, the I
A film made of the same material as the passivation film formed on the circuit formation surface of the C chip is formed.

According to the third aspect of the invention, since the passivation film is formed on the back surface of the liquid crystal driving IC chip, the warp of the liquid crystal driving IC chip can be suppressed.

Further, in the liquid crystal display device according to a fourth aspect of the invention, the film thickness of the passivation film formed on the back surface of the IC chip is the film thickness of the passivation film formed on the circuit formation surface of the IC chip. It is characterized in that it is formed with a thicker dimension.

According to the invention described in claim 4, since a film having a thickness larger than that of the passivation film formed on the circuit forming surface is formed on the back surface of the liquid crystal driving IC chip, the liquid crystal is formed. When the driving IC chip is diced, the liquid crystal driving IC chip is warped such that the back surface of the IC chip is inside. Then, when this liquid crystal driving IC chip is bonded to a flexible wiring substrate or a transparent electrode substrate using a thermosetting resin, a force is applied in the direction of the circuit forming surface side of the liquid crystal driving IC chip. This allows
The liquid crystal driving IC chip becomes flat when connected.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a liquid crystal driving IC chip and a liquid crystal display device of the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic side view showing an embodiment of the present liquid crystal driving IC chip 1. As shown in FIG. 1, the present liquid crystal driving IC chip 1 has a silicon substrate 2.

A circuit (not shown) composed of a transistor, a diode, a resistor, a capacitor and the like is formed on the circuit forming surface of the silicon substrate 2. A plurality of aluminum wirings 3 are formed on the circuit formation surface, and the aluminum wirings 3 are extended to the respective end portions of the silicon substrate 2 to serve as electrode terminals 4.

FIG. 2 is a schematic sectional view of the liquid crystal driving IC chip 1 shown in FIG. 1 taken along the line AA. As shown in FIG. 2, the circuit forming surface of the silicon substrate 2 is A passivation film 6 made of a material such as silicon nitride is formed in a region other than the surface of each electrode terminal 4. In this embodiment, the passivation film 6 is formed to have a film thickness of about 2 μm.

On the surface side of each of the electrode terminals 4,
Bumps 7 made of a metal material such as gold or nickel are formed, and the electrode terminals 4 and the bumps 7 are formed.
A barrier metal 8 made of a material such as titanium nitride is formed between and.

Further, a film 10 made of silicon nitride, which is the same material as the passivation film 6 formed on the circuit formation surface, is formed on the entire back surface of the IC chip opposite to the circuit formation surface of the silicon substrate 2. Has been done. This I
The film 10 on the rear surface side of the C chip is formed so that its film thickness is larger than the film thickness of the passivation film 6 on the circuit formation surface side. In this embodiment, the film thickness is about 5 μm. Is formed.

In the present embodiment, the film thickness of the film 10 on the back surface side of the IC chip is formed thicker than the film thickness of the passivation film 6 on the circuit formation surface side, but it is not limited to this. The passivation film 6 on the circuit formation surface side may be the same as or slightly thinner than the passivation film 6.

Next, the liquid crystal display device 11 of this embodiment having the above-mentioned liquid crystal driving IC chip 1 will be described with reference to FIG.

This liquid crystal display device 11 has a flexible wiring board 12, and this flexible wiring board 1
On the circuit surface of the film substrate 13 that constitutes the element 2, a plurality of electrodes 14 formed by plating a material such as copper with tin, gold, nickel or the like.
And the liquid crystal driving IC among the electrodes 14 is formed.
The tip portion of the chip 1 connected to the electrode terminal 4 is a connection terminal 15. In addition, each of the electrodes 14 is extended to the tip portion of the film substrate 13, and the lead electrode 1
It is supposed to be 6.

Further, the liquid crystal display device 11 has a liquid crystal display panel 20 in which a liquid crystal 19 is sealed in a space between a pair of transparent substrates 18, and a plurality of liquid crystal display panels 20 are provided on opposite surfaces of the pair of transparent substrates 18, respectively. Transparent electrode 21 is formed. One end of each transparent electrode 18 formed on the lower transparent substrate 18 serves as an electrode terminal 22 connected to the lead electrode 16 of the flexible wiring substrate 12.

The electrode terminals 4 of the liquid crystal driving IC chip 1 are electrically connected to the connection terminals 15 of the flexible wiring board 12, and the lead electrodes 16 of the flexible wiring board 12 are , Are electrically connected to the respective electrode terminals 22 of the liquid crystal display panel 20, whereby the liquid crystal display device 11 is formed.

Next, the step of connecting the bumps 7 of the liquid crystal driving IC chip 1 to the connection terminals 15 of the flexible wiring board 12 will be described.

First, the flexible wiring board 12 is placed so that the connection terminals 15 face upward, and then an epoxy resin film containing conductive particles as an adhesive material is placed on the flexible wiring board 12. Liquid crystal drive I
It is attached to a portion corresponding to the position where the C chip 1 is arranged. Next, with the circuit forming surface of the liquid crystal driving IC chip 1 facing downward, each bump 7 of the liquid crystal driving IC chip 1 is turned on.
The liquid crystal driving IC chip 1 is placed on the upper surface of the flexible wiring board 12 while aligning with each connection terminal 15 of the flexible wiring board 12 and pressure-bonded while applying heat and pressure. Then, the resin film is cured to form the bumps 7 of the liquid crystal driving IC chip 1 and the connection terminals 15 of the flexible wiring board 12.
And are connected via conductive particles.

In this embodiment, the bumps 7 of the liquid crystal driving IC chip 1 and the flexible wiring board 12 are used.
Although a resin film (ACF) containing conductive particles was used as the connection material with each of the connection terminals 15, the present invention is not limited to this. For example, a resin film (NCF) containing no conductive particles may be used, and a paste adhesive material (ACP) containing conductive particles or a paste adhesive material containing no conductive particles ( NCP) may be used. At this time, when an adhesive material containing no conductive particles is used, the bumps and the connection terminals are directly brought into contact with each other for connection. Furthermore, after each bump 7 and each connection terminal 15 are connected by metal using Au-Sn eutectic or Au-Au eutectic, etc., the periphery is filled with an epoxy resin and heat-cured. Thus, the liquid crystal driving IC chip 1 and the flexible wiring board 12 may be securely bonded.

According to this embodiment, the liquid crystal driving IC
Since the film 10 having a thickness larger than that of the passivation film 6 formed on the circuit formation surface is formed on the back surface of the IC chip of the chip 1, when the liquid crystal driving IC chip 1 is diced, as shown in FIG. The liquid crystal driving IC chip 1 is slightly warped such that the back surface of the IC chip is inside.

Such a liquid crystal driving IC chip 1 is used as an AC
When it is adhered to the flexible wiring board 12 through F, A
Since CF is hardened and contracted by heat, as shown in FIG. 5, the flexible wiring board 12 is connected through the ACF.
A force is applied to the circuit forming surface side of the liquid crystal driving IC chip 1 that is in contact with the liquid crystal driving IC chip 1, and the warp of the liquid crystal driving IC chip 1 to the back side of the IC chip is eliminated. The chip 1 can be flattened.

Therefore, it is possible to prevent the occurrence of cracks in the passivation film 6 on the circuit forming surface side and further cracks in the liquid crystal driving IC chip 1 itself due to the warp of the liquid crystal driving IC chip 1. it can.

Further, since the liquid crystal driving IC chip 1 does not warp, no force is applied to the circuit of the liquid crystal driving IC chip 1, and as a result, its function is impaired. That can be prevented.

Further, as a result of the liquid crystal driving IC chip 1 functioning normally, the liquid crystal display panel 20 connected via the flexible wiring board 12 can be driven normally.

Further, when a resin for protecting the silicon substrate 2 is formed on the back surface of the liquid crystal driving IC chip 1, the passivation film 6 is formed as compared with the case where the resin is directly formed on the silicon substrate 2. By forming it on the film 10 of the same quality, the adhesion with the resin or the like can be improved.

The present invention is not limited to the above embodiment, but various modifications can be made as necessary.

The liquid crystal display device 11 has been described by using the liquid crystal driving IC chip 1 and the liquid crystal display panel 20 connected via the flexible wiring substrate 12, but the present invention is not limited to this. For example, the bump 7 of the liquid crystal driving IC chip 1 and the electrode terminal 22 of each transparent electrode 21 formed on the liquid crystal display panel 20 are connected on the transparent substrate of the liquid crystal display panel 20 by COG (Ch).
ip on Glass) or the like.

[0041]

As described above, according to the liquid crystal driving IC chip of the first aspect of the invention, the liquid crystal driving IC chip is used.
Since the warpage of the C chip is suppressed, it is possible to prevent cracks from being generated in the passivation film on the circuit formation surface side of the liquid crystal driving IC chip, and further, from being cracked in the liquid crystal driving IC chip itself. it can. Further, no force is applied to the circuit of the liquid crystal driving IC chip, and as a result, it is possible to prevent the function from being impaired.

Further, according to the liquid crystal driving IC chip of the second aspect of the invention, since it becomes a flat state in the connected state, cracks are formed in the passivation film on the circuit forming surface side of the liquid crystal driving IC chip. It is possible to further prevent the occurrence of cracks and cracks in the liquid crystal driving IC chip itself. Further, no force is applied to the circuit of the liquid crystal driving IC chip, and as a result, it is possible to prevent the function from being impaired.

Further, according to the liquid crystal display device of the third aspect of the present invention, by suppressing the warp of the liquid crystal driving IC chip, it is possible to allow the liquid crystal display IC chip to function normally without impairing its function. Thus, the connected liquid crystal display panel can be driven normally.

Further, according to the liquid crystal display device of the fourth aspect of the present invention, by preventing the warp of the liquid crystal driving IC chip, the liquid crystal display IC chip can function normally without impairing its function. Thereby, the connected liquid crystal display panel can be driven more normally.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an embodiment of a liquid crystal driving IC chip according to the present invention.

FIG. 2 is a schematic cross-sectional view showing a case where the liquid crystal driving IC chip shown in FIG. 1 is cut along line AA.

3 is a conceptual diagram showing a liquid crystal display device using the liquid crystal driving IC chip shown in FIG.

FIG. 4 is a conceptual diagram showing a state where a warp occurs after dicing of the liquid crystal driving IC chip shown in FIG.

5 is a conceptual diagram showing a flat state after the liquid crystal driving IC chip shown in FIG. 1 is bonded.

FIG. 6 is a conceptual diagram showing a state where a conventional liquid crystal driving IC chip is warped after dicing.

FIG. 7 is a conceptual diagram showing a state where warpage occurs after the liquid crystal driving IC chip shown in FIG. 6 is bonded.

[Explanation of symbols]

1 LCD driving IC chip 2 Silicon substrate 3 Aluminum wiring 4 electrode terminals 6 passivation film 7 bumps 10 A film of the same quality as the passivation film 11 Liquid crystal display 12 Flexible wiring board 13 film substrate 14 electrodes 15 connection terminals 20 LCD display panel

Claims (4)

[Claims] 1. A liquid crystal driving IC chip in which a passivation film is formed on a circuit formation surface, wherein the IC
A liquid crystal driving IC, characterized in that a film made of the same material as the passivation film formed on the circuit forming surface of the IC chip is formed on the back surface of the chip.
Chips. 2. The film formed on the back surface of the IC chip is formed to have a thickness larger than that of a passivation film formed on the circuit formation surface of the IC chip. LCD driving IC chip. 3. A liquid crystal display device comprising a liquid crystal display panel in which liquid crystal is sealed in a gap between a pair of transparent substrates, and a liquid crystal driving IC chip having a passivation film formed on a circuit formation surface, wherein the IC A liquid crystal display device, wherein a film made of the same material as the passivation film formed on the circuit formation surface of the IC chip is formed on the back surface of the chip. 4. The film according to claim 3, wherein the film thickness of the passivation film formed on the back surface of the IC chip is larger than the film thickness of the passivation film formed on the circuit formation surface of the IC chip. Liquid crystal display device.