JPH04263221A - Thermcompression bonding device - Google Patents

Abstract

PURPOSE:To prevent a cooling head from curving even if heating and cooling are repeated with the thermcompression bonding device which connects the conductor patterns of a flexible printed circuit board to the electrodes of a liquid crystal display element. CONSTITUTION:This thermcompression bonding device consists of a heater block 43 hung with a thermcompression bonding head part 4 from the circuit board 41 by means of plural screws 42, cooling head fixtures 45 freely slidably mounted to the circuit board 41 via compression coil springs 44 and the cooling head 47 held by the cooling head fixtures 45. The above-mentioned device is constituted by providing holding members 48 which have an L-shaped section and are parallel with the longitudinal direction of the cooling head 4 on both sides of the cooling head fixtures 45 and freely slidably mounting the cooling head 47 between the cooling head fixtures 45 and the holding members 48.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermocompression bonding device for connecting a conductor pattern of a flexible printed circuit board to an electrode of a liquid crystal display element.

[0002] A liquid crystal display element generally has a liquid crystal sealed between two glass substrates facing each other, and includes a plurality of transparent electrodes arranged in the X-axis direction formed on the two glass substrates, A pixel is formed at each intersection with a plurality of transparent electrodes arranged in the Y-axis direction. Each of these transparent electrodes is connected to a drive circuit for applying a voltage, but as the pixel arrangement density increases, the arrangement interval of the transparent electrodes becomes smaller, and the semiconductor integrated circuit for driving becomes smaller. It is becoming difficult to connect the mounted printed circuit board and the liquid crystal display element using, for example, an elastic connector.

Therefore, in recent years, TAB (Tap
e Automated Bonding) technology is used to attach semiconductor chips to flexible printed circuit boards (hereinafter referred to as F).
There is a shift toward a tablet mounting method in which the conductor pattern of the FP board is directly thermocompression bonded to the liquid crystal display element.

0004

2. Description of the Related Art FIG. 3 is a plan view showing a tablet made of an FP board, FIG. 4 is a plan view showing a tablet mounting method on a liquid crystal display element, FIG. 5 is a plan view showing a conventional thermocompression bonding device, and FIG.
FIG. 2 is a diagram showing a method of thermocompression bonding a tablet.

In FIG. 3, when a semiconductor chip is mounted on a liquid crystal display element by the tablet mounting method, a tablet 1 is mounted using an FP board made of polyimide resin, for example.
is formed, and the semiconductor chip 2 is mounted on the inner lead portion of the conductive pattern 11 formed on the tablet 1. The tablet 1 also has a plurality of connection terminal parts 12 arranged in a row horizontally at intervals of 1 mm, for example, on one side, and a plurality of connection terminal parts 13 arranged in a row horizontally at intervals of 0.25 mm, for example, on the other side. .

As shown in FIG. 4, the liquid crystal display element 3 has two glass substrates 31 having a plurality of connection terminal portions 32 facing each other, and the plurality of connection terminal portions 32 are arranged on the X axis at intervals of, for example, 0.25 mm. direction or the Y-axis direction. Although not shown, transparent electrodes are connected to each of the connection terminal portions 32. The semiconductor chip 2 is mounted by the tablet mounting method on a glass substrate 31 as shown in the figure.
This is done by stacking the corresponding connection terminal portions 13 of the tablet 1 on the connection terminal portions 32 of the tablets 1 and thermally press-bonding them.

[0007] In order to reduce the manufacturing cost of a liquid crystal display device formed by such a tablet mounting method, a semiconductor chip 2 having as many driving elements as possible built-in is needed.
is mounted on a large tablet 1, with numerous connection terminals 1.
3 to the connection terminal portion 32 of the glass substrate 31 at the same time. From this point of view, a large tablet 1 with a distance of approximately 45 mm between the outermost connection terminal portions 13 is used.

In FIG. 5(a), the conventional apparatus for thermocompression bonding the tablet 1, that is, the FP board to the liquid crystal display element 3, is as follows:
It has a thermocompression bonding head section 4, a moving mechanism 5 for moving the thermocompression bonding head section 4 up and down, and a table 6 on which a liquid crystal display element 3 is placed.
The thermocompression bonding head 4 has a plurality of screws 42 as shown in Fig. 5(b).
A heater block 43 is suspended from the board 41, a cooling head fixture 45 is slidably attached to the board 41 via a compression coil spring 44, and both ends are screwed to the cooling head fixture 45 by screws 46. The cooling head 47 has a convex cross section. The table 6, which is movable in the X-axis direction and the Y-axis direction, includes a thermocompression bonding table 61 on which the liquid crystal display element 3 is placed, and a cooling head 46.
It is equipped with a preheating stand 62 for preheating.

[0009] Hereinafter, a method for thermocompression bonding a tablet to a liquid crystal display element will be explained in detail with reference to FIG. (2) Preheating of the cooling head: Prior to thermocompression bonding, the thermocompression bonding head portion 4 is lowered onto the preheating table 62 as shown in FIG. 6(a). When the thermocompression bonding head section 4 is lowered, the cooling head 47 first comes into contact with the preheating table 62, and when the thermocompression bonding head section 4 is further lowered, the heater block 43 abuts against the cooling head 47. The preheating table 62 is covered with a material that is difficult to conduct heat, and the cooling head 47 is preheated by the heater block 43.

[0010] Thermocompression bonding: The thermocompression bonding head 4 is once raised and the thermocompression bonding table 61 is moved below the thermocompression bonding head 4 as shown in FIG. 6(b), and the liquid crystal display element on the thermocompression bonding table 61 is moved. 3, and the thermocompression bonding head 4 is lowered again. When the thermocompression bonding head 4 descends, the cooling head 46 presses the tablet 1 against the liquid crystal display element 3 with a predetermined pressure (for example, 20 kg), and then the heater block 43 heats the cooling head 47 (for example, 14 kg).
(20 seconds at 0° C.) The tablet 1 is thermocompressed onto the liquid crystal display element 3.

■ Cooling of thermocompression bonding part: After heating the cooling head 47 for a predetermined time, the heater block 43 is raised as shown in FIG.
is pressed against the liquid crystal display element 3 and blows nitrogen gas for a predetermined period of time (for example, 30 seconds) to cool the cooling head 47, the tablet 1, and the thermocompression bonded portion of the liquid crystal display element 3. When the cooling of the thermocompression bonding section is completed, the thermocompression bonding head section 4 further rises and returns to the state of (2) again.

0012

FIG. 7 is a diagram showing problems in a conventional thermocompression bonding apparatus. In the conventional thermocompression bonding apparatus, the cooling head 47 is initially formed to abut against the tablet 1 with a uniform force. However, both ends of the cooling head 47 are fixed to the cooling head fixture 45 by screws 46, and when heating and cooling are repeated, the cooling head 47 curves as shown in FIG. 7(a) and the central portion protrudes. As a result, Figure 7 (
b) As shown in the figure, the operating time of the cooling head 47 is 3000.
As time passes, the effects of this start to appear, and although there is no displacement of the connection terminals at the center, which is the first contact point when pressing against the liquid crystal display element 3, as the cooling head 47 descends, the tablet 1 gradually shifts from side to side. There was a problem in that the tablet 1 was stretched out, causing a large positional shift at the outermost connection terminal portion of the tablet 1.

An object of the present invention is to provide a thermocompression bonding device in which the cooling head does not bend even after repeated heating and cooling.

[0014]

[Means for Solving the Problems] FIG. 1 is a side view showing the main parts of a thermocompression bonding apparatus according to the present invention. The same objects are represented by the same symbols throughout the figures.

The above problem is solved by the heater block 43 in which the thermocompression head portion 4 is suspended from the substrate 41 by a plurality of screws 42;
A cooling head fixture 45 slidably attached to the substrate 41 via a compression coil spring 44;
This is a thermocompression bonding device consisting of a cooling head 47 held by a cooling head fixture, in which holding members 48 having an L-shaped cross section and parallel to the length direction of the cooling head 47 are provided on both sides of a cooling head fixture 45. This is achieved by the thermocompression bonding apparatus of the present invention in which the cooling head 47 is slidably mounted between the cooling head 45 and the holding member 48.

[0016]

[Operation] In Fig. 1(a), holding members with an L-shaped cross section and parallel to the length direction of the cooling head are provided on both sides of the cooling head fixture, and the cooling head is slid between the cooling head fixture and the holding member. By being movably mounted, even if the cooling head expands due to heating, it can escape in the length direction and return to its original state when cooled. That is, it is possible to realize a thermocompression bonding device in which the cooling head does not curve even after repeated heating and cooling.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings. Note that FIG. 1(b) is a side view showing another embodiment of the thermocompression bonding apparatus according to the present invention, and FIG. 2 is a side view showing a modified example of the thermocompression bonding apparatus according to the present invention.

In FIG. 1(a), the embodiment of the present invention includes a heater block 43 suspended from a substrate 41 by a plurality of screws 42, and a cooling block 43 slidably attached to the substrate 41 via a compression coil spring 44. A head fixture 45 and a pair of holding members 4 having an L-shaped cross section and parallel to the length direction of the cooling head 47.
8 and the cooling head fixing tool 4 by opposing screws 49.
The thermocompression bonding head portion 4 includes a cooling head 47 that is slidably attached to a cooling head fixture 45 via a holding member 48 that is screwed onto the side surface of the cooling head 47 . Note that the holding member 4
8 is provided with drop-off prevention claws 50 at both ends to prevent the cooling head 47 from falling off.

In this way, the holding members having an L-shaped cross section and parallel to the length direction of the cooling head are provided on both sides of the cooling head fixture, and the cooling head can be slid freely between the cooling head fixture and the holding member. When installed, even if the cooling head expands due to heating, it can escape in the length direction and return to its original state when cooled. As a result, positional deviation does not occur even if the cooling head is used for more than 10,000 hours. That is, it is possible to realize a thermocompression bonding device in which the cooling head does not curve even after repeated heating and cooling.

Another embodiment of the present invention shown in FIG. 1B includes a heater block 43 suspended from a substrate 41 by a plurality of screws 42, and a compression coil spring 44 connected to the substrate 41.
A cooling head fixture 45 is slidably attached to the cooling head 47, and a cooling head 47 is provided with elongated holes 51 near both end faces.
and screws 46 constitute the thermocompression bonding head portion 4, and the cooling head 47 is slidably screwed onto the cooling head fixture 45 by the screws 46.

[0021] As described above, the thermocompression head section in which the cooling head having long holes provided in the vicinity of both end faces is slidably screwed onto the cooling head fixing tool with screws passing through the long holes also has a cooling head. Even if it expands when heated, it is able to escape in the length direction, and returns to its original state when cooled. That is, it is possible to realize a thermocompression bonding device in which the cooling head does not curve even after repeated heating and cooling.

A modified example of the thermocompression bonding apparatus according to the present invention shown in FIG. 2 is one in which the effect of the thermocompression bonding head section is further enhanced, and FIG. 2(a) shows a modification of the cooling head 47 shown in FIG.
In the thermocompression bonding head section formed by screwing together, a plurality of metal balls 52 are interposed between the heater block 43 and the cooling head 47, and some metal balls 52 are inserted between the cooling head 47 and the cooling head fixture 45 when screwing them together. A gap 54 is provided.

Further, FIG. 2(b) shows, for example, in a thermocompression bonding head portion formed by screwing the cooling head 47 shown in FIG. A plurality of metal rollers 53 are interposed between the heater block 43 and the cooling head 47 via the metal rollers 53.
It is configured to be in contact with That is, the cooling head 47
The friction between the cooling head fixing member 45, the cooling head 47, and the heater block 43 is small, and the cooling head is more effective.

[0024]

As described above, according to the present invention, it is possible to provide a thermocompression bonding apparatus in which the cooling head does not bend even when heating and cooling are repeated.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the main parts of a thermocompression bonding apparatus according to the present invention.

FIG. 2 is a side view showing a modification of the thermocompression bonding apparatus according to the present invention.

FIG. 3 is a plan view showing a tablet made of an FP board.

FIG. 4 is a plan view showing a tablet mounting method on a liquid crystal display element.

FIG. 5 is a diagram showing a conventional thermocompression bonding device.

FIG. 6 is a diagram showing a method of thermocompression bonding a tablet.

FIG. 7 is a diagram showing problems in a conventional thermocompression bonding device.

[Explanation of symbols]

Claims (3)

[Claims] 1. A thermocompression bonding head (4) is attached to a heater block (43) suspended from a substrate (41) by a plurality of screws (42) and a compression coil spring (44) to the substrate (41).
Cooling head fixture (45) slidably attached to the cooling head fixture (41)
) and a cooling head (47) held by the cooling head fixture (45), the holding member having an L-shaped cross section and parallel to the length direction of the cooling head (47). (48) are provided on both sides of the cooling head fixture (45), and the cooling head fixture (45) and the holding member (48) are provided on both sides of the cooling head fixture (45).
) The cooling head (47) is slidably mounted between the thermocompression bonding apparatus. 2. A thermocompression bonding head (4) is attached to the substrate (41) via a heater block (43) suspended from the substrate (41) by a plurality of screws (42) and a compression coil spring (44).
Cooling head fixture (45) slidably attached to the cooling head fixture (41)
) and a cooling head (47) held by the cooling head fixing device (45), the cooling head (47) has elongated holes (51) near both end surfaces thereof. The cooling head (47) is attached to the cooling head fixture (45) by screws (46) passed through the holes (51).
A thermocompression bonding device characterized by being slidably attached to. 3. In the thermocompression bonding apparatus according to claim 1 or 2, a plurality of balls (52) or rollers (53
) is interposed between a heater block (43) and a cooling head (47).