JPH03156941A - Mounting of semiconductor chip - Google Patents

Abstract

PURPOSE:To directly mount a semiconductor chip on a liquid-crystal panel by a method wherein a heated semiconductor chip is pressed to a panel and a tip part of a protrusion which has been passed by softeneing a thermoplastic film is brought into contact with an electrode on the panel. CONSTITUTION:A thermoplastic film 5 is applied in advance to an electrode formation face of a panel 1; protrusions 32 composed of a metal are formed on electrodes 31 on a semiconductor chip 3 to be mounted. During a mounting operation, the heated semiconductor chip 3 is pressed to the panel 1; tip parts of the protrusions 32 which have been passed by softening the thermoplastic film 5 are brought into contact with electrodes 11 on the panel 1. Thereby, a short circuit between the electrodes is not caused, and the semiconductor chip in which an interval between the electrodes is small can be mounted directly on a liquid-crystal panel.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for connecting a liquid crystal panel and a drive circuit in a liquid crystal display device, the present invention aims to provide a mounting method that allows semiconductor chips to be directly mounted on a liquid crystal panel. At the same time as a thermoplastic film is applied, metal protrusions are formed on the electrodes on the semiconductor chip to be mounted, and during mounting, the heated semiconductor chip is pressed against the panel, softening the thermoplastic film and penetrating the tips of the protrusions. is configured to contact an electrode on the panel.

[Industrial application field]

The present invention relates to a method for connecting a liquid crystal panel and a drive circuit in a liquid crystal display device, and particularly to a mounting method that allows semiconductor chips to be directly mounted on a liquid crystal panel.

2. Description of the Related Art In recent years, liquid crystal display devices have been adopted as display devices in various electronic devices, and accordingly, there has been a demand for smaller size and lower cost of liquid crystal display devices. However, with the method of mounting the drive circuit on a printed wiring board and connecting it to the liquid crystal panel,
It is not possible to achieve the currently required miniaturization and cost reduction of liquid crystal display devices. Therefore, methods of directly mounting drive circuits on the liquid crystal panel in high density are being considered.

[Prior Art] FIG. 2 is a side sectional view showing a conventional semiconductor chip mounting method.

As shown in FIG. 2(a), a liquid crystal panel 1 according to the conventional mounting method has a plurality of electrodes 11 on its surface, and an anisotropic conductive film 2 is adhered to the surface of the liquid crystal panel 1. The anisotropic conductive film 2 is composed of an insulating substrate 21 and conductive particles 22 dispersed in the substrate 21. In a steady state, the conductive particles 22 are separated from each other and the anisotropic conductive film 2 has insulating properties.

On the other hand, an electrode 31 is formed on the semiconductor chip 3 by means such as plating, and as shown in FIG. By pressing against the liquid crystal panel 1, the conductive particles 22 sandwiched between the electrode 11 and the electrode 31 come into contact with each other as shown in FIG. 2(C), and the electrode 11 and the electrode 3
1 are electrically connected via an anisotropic conductive film 2.

[Problem to be solved by the invention]

In conventional semiconductor chip mounting methods, if the distance between adjacent electrodes is wide, there will be a portion between the electrodes where conductive particles do not come in contact with each other, and insulation can be maintained. However, when the gap between the electrodes becomes narrow, there is no part where the conductive particles do not come into contact with each other, and in the case of a semiconductor chip with a small gap between the electrodes, there is a problem that short circuits occur between the electrodes.

An object of the present invention is to provide a mounting method that allows semiconductor chips to be directly mounted on a liquid crystal panel.

[Means to solve the problem]

FIG. 1 is a side cross-sectional view showing a semiconductor chip mounting method according to the present invention. The same objects are represented by the same symbols throughout the plan.

The above problem is solved by applying a thermoplastic film 5 in advance to the electrode forming surface of the panel 1, and forming protrusions 32 made of metal on the electrodes 31 on the semiconductor chip 3 to be mounted. This is achieved by the semiconductor chip mounting method according to the present invention, which presses the chip 3 and softens the thermoplastic film 5 so that the tips of the protrusions 32 penetrating it come into contact with the electrodes 11 on the panel 1.

[For production]

In Fig. 1, a thermoplastic film is applied in advance to the electrode formation surface of the panel, metal protrusions are formed on the electrodes on the semiconductor chip to be mounted, and the heated semiconductor chip is pressed against the panel during mounting. By softening the plastic film and bringing the tips of the penetrating protrusions into contact with the electrodes on the panel, short circuits between the electrodes are eliminated and semiconductor chips with small electrode spacing can be directly mounted on the liquid crystal panel.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 3 is a diagram showing an embodiment of the present invention, and FIG. 4 is a diagram showing a modification of the present invention.

As shown in FIG. 1(a), the liquid crystal panel 1 in the mounting method of the present invention has a plurality of electrodes 11 on the surface.
A thermoplastic film 5 is previously applied to the surface of the .

On the other hand, electrodes 31 are formed on the semiconductor chip 3 as shown in FIG. 1, and each electrode 31 is formed with a protrusion 32 made of metal. Note that an effective method for forming the protrusion 32 on the electrode 31 is to bond a wire to the electrode 31 and then cut the wire so that the length is uniform.

Incidentally, as shown in FIG. 3(a), the formation of the protrusion 32 in one embodiment of the present invention is performed using an Au wire with a diameter of 25 μm, similar to the first bonding in ordinary wire bonding.
After bonding the wire 33 to the electrode 31, the Au wire is cut. In the figure, 34 is a capillary for bonding the ^U wire 33. With this method, the average thickness c = 27.4 μm
The average height h of the projections 32 formed on the electrode 31 is 81.2 mm from the surface of the semiconductor chip 3, as shown in FIG.
It becomes a μ surface.

During mounting, the semiconductor chip 3 is attracted to the heating head 4 as shown in FIG. As shown in FIG. 1(C), the heated electrodes 31 and protrusions 32 soften the thermoplastic film 5, and the tips of the protrusions 32 that penetrate the thermoplastic film 5 contact the electrodes 11 of the liquid crystal panel 1 and are bonded by thermocompression. be done.

Note that the protrusion 32 formed by cutting the Au wire bonded to the electrode 31 has a height variation of about 10 μm due to errors in cutting and errors in the thickness of the electrode 31.
The protrusions 32 formed of wire are flexible, so variations are absorbed, and when mounted, the tips of the protrusions 32 touch the liquid crystal panel 1.
uniformly contacts the electrodes 11 of.

Further, as a means of forming protrusions on the electrode, there is a method of plating the electrode. For example, as shown in Figure 4(a), by applying ^U plating to the electrode base, the peripheral edge is raised,
An electrode 31 having an average thickness c=13.3 μm with protrusions 32 having an average height h=17.1 μm is formed. Note that in this case, the height variation of the protrusions 32 can be reduced to about 0.2 μm.

20kg of semiconductor chips 3 heated to about 150°C
/CIl+ for 20 seconds against the liquid crystal panel 1, the heated electrodes 31 and protrusions 32 softened the thermoplastic film 5 and penetrated the thermoplastic film 5, as shown in FIG. 4(b). The tips of the protrusions 32 come into contact with the electrodes 11 of the liquid crystal panel 1 and are bonded by thermocompression.

In this way, a thermoplastic film is applied in advance to the electrode formation surface of the panel, metal protrusions are formed on the electrodes on the semiconductor chip to be mounted, and the heated semiconductor chip is pressed against the panel during mounting. By softening the film and bringing the tips of the penetrating protrusions into contact with the electrodes on the panel, short circuits between the electrodes are eliminated and semiconductor chips with small electrode spacing can be directly mounted on the liquid crystal panel.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a mounting method that allows semiconductor chips to be directly mounted on a liquid crystal panel.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a semiconductor chip mounting method according to the present invention, FIG. 2 is a side sectional view showing a conventional semiconductor chip mounting method, and FIG. 3 is a diagram showing an embodiment of the present invention. FIG. 4 is a diagram showing a modification of the present invention. In the figure, 1 is a panel, 3 is a semiconductor chip, 4 is a heating head, 5 is a thermoplastic film, 11 is an electrode,
31 is an electrode, 32 is a protrusion, 33 is an Au wire, and 34 is a capillary. Q capital 240

Claims (1)

[Claims] A thermoplastic film (5
), and at the same time forming protrusions (32) made of metal on the electrodes (31) on the semiconductor chip (3) to be mounted,
During mounting, the heated semiconductor chip (3) is pressed against the panel (1), and the tips of the protrusions (32) that have softened and penetrated the thermoplastic film (5) are attached to the panel (1).
) A method for mounting a semiconductor chip, characterized in that the semiconductor chip is brought into contact with an electrode (11) on a semiconductor chip.