JPH04249331A - Wire bonding method and bonding tool - Google Patents

Abstract

PURPOSE:To accurately set the feed position of a wire and to reduce the size of a pressure face to a minimum regarding the wire bonding method and the bonding tool of various kinds of printed wiring boards which are used widely when various kinds of electronic apparatuses are constituted. CONSTITUTION:A clamper 14 which grips the tip of a wire 1 fed form a hole for wire feed use at a bonding tool 13 and which energizes a tension onto said wire 1 is installed on the side opposite to said hole for wire feed use. Said wire 1 onto which the tension has been energized by using said clamper 14 is bonded to a pad on a substrate by using the pressure face of said bonding tool 13.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire bonding method and bonding tool for various printed wiring boards, which are widely used in the construction of various electronic devices. Recently, various highly integrated electronic components have been mounted at high density on printed circuit boards, especially those installed in large computers, etc., and the size of the pads formed on the printed wiring boards (hereinafter referred to as "boards") has increased. Along with the trend toward miniaturization of pads, the wires used for repairing and modifying boards are also becoming thinner in response to the miniaturization of pads.

[0002] For this reason, the pressing surface of the bonding tool that presses the wire against the pad and joins it using ultrasonic waves or heat must also be miniaturized. Because the bonding location varies, there is a need for a wire bonding method and bonding tool that can accurately position the wire to provide a minimum pressure surface.

0003

2. Description of the Related Art Conventional wire bonding methods and bonding tools, as shown in FIG. One end side of the bonding tool 3, which has a hole 3-1 for wire feed in the same direction as the supply of the wire 1, is fixed vertically to the tip of the ultrasonic transducer 2 directly connected to the ultrasonic oscillator as shown in FIG. By doing so, the pressing surface 3a of the bonding tool 3 is made to face a substrate (not shown) in parallel. Then, from a wire feeding device (not shown), the tip of the wire 1, which has been passed through the wire feed hole 3-1 of the bonding tool 3 shown in FIG. The tip of the wire 1 is bent by lowering it and pressing it against a pad on a substrate (not shown), so ultrasonic waves are applied from the ultrasonic transducer 2 to the bonding tool 3 to bend the tip of the wire 1 on the pressing surface 3a. and the pads on the substrate are bonded.

0004

[Problems to be Solved by the Invention] The problems with the conventional wire bonding method and bonding tool described above are as follows.
The wire 1 supplied to the pressing surface 3a of the bonding tool 3 is in a free state in the width in the wire feed direction, and when bonding the tip of the wire 1 to the pad of the substrate, it moves against the pressing surface 3a of the bonding tool 3. wire 1
Since the position of the joint portion changes, it is necessary to make the width W of the pressing surface 3a in the wire feed direction approximately four times the diameter D of the wire 1, as shown in FIG. 7(b).

Therefore, the wire 1 is connected to the pad of the board.
Since the bonding position changes and the bonding is performed at the large pressing surface 3a, a problem arises in that a plurality of wires 1 cannot be bonded to the same pad. SUMMARY OF THE INVENTION In view of the above problems, the present invention aims to provide a new wire bonding method and bonding tool that can accurately supply the wire and minimize the size of the pressing surface.

[0006]

[Means for Solving the Problems] The present invention provides wire feeding holes 13-
A clamper 14 that grips the tip of the wire 1 fed from the wire 1 and applies tension to the wire 1 is provided on the opposite side of the wire feed hole 13-1 as shown in FIG. Either the tip of the wire 1 is held by the clamper 14, or the tip of the wire 1 fed from the wire feed hole 13-1 is bent by the forming jig 15 shown in FIG. 3 as shown in FIG. The bonding tool 13 is gripped by the clamper 14, and the wire 1 is bonded by pressing the pressing surface 13a of the bonding tool 13 against the pad on the substrate while applying tension to the wire 1 by the clamper 14 as shown in FIG. .

As another method, as shown in FIG. 5, a bonding tool 23 is provided in which a pressing surface 23a and a guide groove 23-2 for guiding the feeding of the wire 1 are formed on the periphery of the pressing surface 23a.
The wire 1 is bonded to the pad on the substrate by using a .

[0008]

[Operation] In the present invention, the tip of the wire 1 supplied from the wire feed hole 13-1 of the bonding tool 13 to the pressing surface 13a is gripped, and a clamper provided on the opposite side of the wire feed hole 13-1 is used. 14 and the wire 1 between it and the wire feed hole 13-1.
When tension is applied to the above-mentioned pressing surface 13a, the passing position of the wire 1 with respect to the pressing surface 13a is always constant, and when the pressing surface 13a of the bonding tool 13 is pressed and bonded to the pad on the substrate in this state, the bonded wire 1 is It is bonded to the pad in a precise position.

Further, as shown in FIG. 5, a guide groove 23 for guiding the feed of the wire 1 is provided on the pressing surface 23a and its periphery.
By using the bonding tool 23 formed with the wire 2, the wire 1 fed from the wire feed hole 23-1 is guided to the pressing surface 23a by the guide groove 23-2, and the feeding position becomes accurate. Therefore, the supply position of the wire 1 becomes constant and the width of the pressing surfaces 13a, 23a in the wire supply direction can be minimized, so that the bonding position of the wire 1 to the pad on the substrate becomes accurate, and the same pad It becomes possible to join a plurality of wires 1 to each other.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 5. FIG. 1 is a schematic diagram showing a wire bonding method according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing the tip of a bonding tool according to the first embodiment, and FIG. 3 is a schematic diagram showing a wire forming jig according to the present embodiment. , FIG. 4 is a schematic diagram showing the wire bending order by the forming jig, and FIG. 5 is a schematic diagram showing the tip of the bonding tool of the second embodiment.

In the figure, the same members as in FIGS. 6 and 7 are given the same symbols, and 13 and 23 are bonding tools for bonding wires to pads during board repair and modification, and 14 is a wire bonding tool. A clamper 15 clamps the tip and applies tension, and 15 is a forming jig that shapes the tip of the wire into the shape of the tip of a bonding tool. As shown in FIG. 2(a), the first bonding tool 13 is formed so that one end of the prism can be fixed to the ultrasonic transducer, and the other end is provided with a pressing surface 13a, and one side of the prism is inclined. A wire feeding hole 13-1 is formed on that surface in the same shape as the conventional one in the same direction as the feeding direction of the wire 1, and a pressing surface 13a is formed as shown in FIG. 2(b).
The width W in the wire feed direction is approximately 1.5D relative to the diameter D of the wire 1.

The clamper 14 is connected to the wire feed hole 13 of the first bonding tool 13 as shown in FIG.
- 1 to the pressing surface 13a and protrudes to the opposite side, and is arranged at the upper part of the wire feed hole 13-1 of the first bonding tool 13 opposite to the wire feed hole 13-1. , when the tip of the wire 1 is gripped, the wire 1 is tensioned and biased by the wire feed hole 13-1.

The forming jig 15 has a rectangular parallelepiped recess 15-1 into which the pressing surface 13a of the first bonding tool 13 can fit, in the center of the block, as shown in FIG. 3(a). 1, the pressing surface 13 of the first bonding tool 13 as shown in FIG.
The wire 1 supplied to the first bonding tool 1
3 from the wire feed hole 13-1 to the pressing surface 13a
A forming groove 15-2 is formed in the direction of the clamper 14 through the groove 15-2, and an inclined surface guides the wire 1 into the groove 15-2 from the bottom surface of the recess 15-1 and the opposing side surface. has been established.

The second bonding tool 23 is shown in FIG.
b) As shown in FIG. 1, the width W of the pressing surface 23a in the wire feed direction is formed to be 2D relative to the diameter D of the wire 1, so that the width W of the pressing surface 23a is 2D relative to the diameter D of the wire 1.
Double guide grooves (23-2) are formed on the pressing surface 23a, the wire supply side, and the wire discharge side, as shown in FIG. 5(a). The wire bonding method using the first bonding tool described above involves lowering the first bonding tool 13 fixed to the ultrasonic transducer 2 as shown in FIG. 1, and pressing the tip as shown in FIG. 2(a). Face 13
A is formed with a pad on a substrate (not shown) to form a gap of a certain size, for example, slightly larger than the diameter of the wire 1.

Then, the wire 1 supplied from the wire feed hole 13-1 is inserted into this gap, and the tip of the wire 1 is placed on the upper side opposite to the wire feed hole 13-1 as shown in FIG. The provided clamper 14 is held, and the clamper 14 and the wire feed hole 1 are connected to each other.
3-1 applies tension to the wire 1 in contact with the pressing surface 13a. Further, in order to automate the tension application, the wire 1 fed from the wire feed hole 13-1 is inserted into the gap between the pressing surface 13a of the bonding tool 13 and the pad, as shown in FIG. 4(a). As shown, the tip of the wire 1 is bent into an inverted F-shape, and in this state, the pressing surface 1 is inserted into the recess 15-1 of the forming jig 15 shown in FIG.
3a, the tip of the wire 1 becomes as shown in Fig. 4 (
By bending the tip end into an inverted ladder shape as shown in b), and then letting out the wire 1 and bending it again, the wire 1 is bent again.
), the wire 1 is shaped so that its tip is located at the position of the clamper 14, and this tip is gripped by the clamper 14 to apply tension to the wire 1.

Then, as shown in FIG. 1, the tip of the bent wire 1 is gripped by the clamper 14 and tension is applied to the wire 1 through the wire feed hole 13-1, and in this state, the bonding tool 13 is is lowered to press the wire 1 with the pressing surface 13a and bond it to a pad on a substrate (not shown) using ultrasonic waves. Further, in the bonding method using the second bonding tool 23, as shown in FIG. 5(a), the pressing surface 23a at the tip has a constant gap with a pad on a substrate (not shown), for example, approximately equal to the diameter of the wire 1. Lower the bonding tool 23 as shown, and feed the wire 1 through the wire feed hole 23-1 onto the pressing surface 23.
By supplying wire 1 to point a, the tip of the wire 1 is bent by the guide groove 23-2 and the pad, and the tip protrudes from the discharge side, and in this state, the bonding tool 23 is further lowered to be located on the pressing surface 23a. Wire 1 is joined to the pad.

As a result, bonding tools 13, 2
The feeding position of the wire 1 to the pressing surface 13a becomes accurate.
, 23a in the wire supply direction, the bonding position of the wire 1 to the pad on the substrate becomes accurate, and a plurality of wires 1 can be bonded to the same pad. Although this embodiment has been described with respect to a wire bonding method and a bonding tool for printed circuit boards, the present invention is not limited to only printed circuit boards, and may be used for wire bonding methods and bonding tools for semiconductor devices.

[0018]

[Effects of the Invention] As is clear from the above description, the present invention has advantages such as being able to accurately supply the wire and minimizing the pressing surface of the bonding tool with an extremely simple method and configuration. Therefore, it is possible to provide a wire bonding method and a bonding tool that can be expected to be significantly economical and to improve reliability.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a wire bonding method according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing the tip of the bonding tool of the first embodiment.

FIG. 3 is a schematic diagram showing the wire forming jig of this example.

FIG. 4 is a schematic diagram showing the wire bending order by the present forming jig.

FIG. 5 is a schematic diagram showing the tip of a bonding tool of a second embodiment.

FIG. 6 is a schematic diagram showing a conventional wire bonding method.

FIG. 7 is a schematic diagram showing a conventional bonding tool.

[Explanation of symbols]

Claims (3)

[Claims] Claim 1: A clamper (14) that grips the tip of the wire (1) supplied from the wire feed hole (13-1) of the bonding tool (13) and applies tension to the wire (1). is provided on the opposite side of the wire feed hole (13-1), and the wire (1), which is tensioned by the clamper (14), is placed on the pressing surface (13a) of the bonding tool (13).
A wire bonding method characterized by bonding a wire to a pad on a substrate. [Claim 2] The bonding tool (13)
The tip of the wire (1) fed from the wire feed hole (13-1) is molded by forming a molding groove (15-2) for the wire (1) in the recess (15-1). The wire joining method according to claim 1, characterized in that the wire joining method is formed using a jig (15). 3. A wire feeding hole (2
A bonding tool for wire joining, characterized in that a guide groove (23-2) is formed in the direction in which the wire (1) fed from the wire (3-1) is fed out.