JPH04225540A - Wire bonder - Google Patents

Abstract

PURPOSE:To use a covered wire in a wire bonding device of a ball bonding type. CONSTITUTION:On clamp surfaces 24a, 25a of metallic clampers 24, 25 which are electrically connected to a discharge voltage producing circuit 5, projections 26 to 29 which come into contact with a wire body 22 biting an insulting film 23 at clamping are provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball bonding wire bonding apparatus.

In recent years, with the miniaturization of IC chips, the pitch of pads for wire connection has become narrower, and accordingly, the pitch of wires arranged has become narrower. When the pitch of the wires becomes narrower than 100 μm, there is a risk that the wires will come into contact with each other.

[0003] Therefore, as a countermeasure for increasing the density of wiring, coated wire coated with an insulating material has been proposed.

[0004] A ball bonding type wire bonding device is required to have a structure that is compatible with the above-mentioned coated wire.

[0005]

2. Description of the Related Art FIG. 5 shows a conventional ball bonding type wire bonding apparatus 1.

2 is a ceramic capillary, 3 and 4 are copper clampers, 5 is a discharge voltage generating circuit, and 6 is an electrode. The capillary 2 moves in the direction of arrow A, the clampers 3 and 4 move in the directions of arrows B and C, and the electrode 6 moves in the direction of arrow D.

The wire 7 passes through the clampers 3 and 4, passes through the center hole 2a of the capillary 2, and projects downward from the capillary 2.

[0008] The clampers 3, 4 and the electrode 6 are electrically connected to a discharge voltage generating circuit 5. An arc discharge 9 occurs between the lower end of the wire 7 and the electrode 6, forming a ball 10 at the lower end of the wire 7.

Ball bonding is performed using this ball 10 to pads of an IC chip.

0010

As shown in FIG. 6, the clampers 3 and 4 have a structure in which both clamp surfaces 3a and 3b are flat surfaces.

Therefore, if the wire 7 is a coated wire, the clampers 3 and 4 cannot be electrically connected to the wire. Therefore, no arcing occurs, no balls are formed,
Ball bonding is not possible.

[0012] Here, it is conceivable to embed a heater in the clampers 3 and 4 and remove the coating by heat, but if this is done, the area where the coating is removed becomes large, and the wires between the wires are Insulation will be lost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a wire bonding device that enables ball bonding using coated wire.

[0014]

[Means for Solving the Problem] The invention as claimed in claim 1 provides a clamper with a clamping surface provided with a protrusion large enough to bite into the insulating coating of the wire and reach the wire body during clamping. That is.

[0015] According to a second aspect of the invention, the protrusion is a protrusion extending in a direction perpendicular to the wire.

[0016] According to the third aspect of the invention, a plurality of protrusions are provided. According to a fourth aspect of the present invention, the protrusion has a triangular cross section.

[0017]

[Operation] The protrusion of the invention as claimed in claim 1 ensures electrical continuity between the clamper and the wire body while keeping the destruction of the coating very localized.

[0018] The protruding portion of the second aspect of the invention allows the clamper to be electrically connected to the wire body no matter where the wire is located on the clamper.

The plurality of protrusions of the third aspect of the invention provide a plurality of electrically conductive points between the clamper and the wire body, thereby ensuring electrical continuity.

[0020] The protrusion portion having a triangular cross section according to the third aspect of the present invention ensures that the protrusion portion is bitten into the coating.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a wire bonding apparatus 20 according to an embodiment of the present invention. In the figure, the same reference numerals are given to the parts corresponding to the constituent parts shown in the figure, and the explanation thereof will be omitted.

Reference numeral 21 is a coated wire, and the diameter d is, for example, 2.
A gold wire body 22 of 5 μm has a thickness t of, for example, 0.
The structure includes an insulating coating 23 made of heat-resistant polyurethane with a thickness of 75 μm.

Clampers 24 and 25 are made of copper and have a diameter D of 10 mm, as shown in FIG. 2, and have flat clamping surfaces 24a and 25a.

Reference numerals 26 and 27 are protrusions, and the clamping surface 2
4b, two wires are formed in parallel, extending in a direction perpendicular to the clamped covered wire 21.

The protrusions 26 and 27 have a triangular cross section, and the height h thereof is set to be approximately equal to the thickness t of the insulating coating 23.

Similarly, the clamp surface 25a of the clamper 25
Also, protrusions 28 and 29 are formed.

Next, the operation of the wire bonding apparatus 20 having the above structure will be explained. As shown in FIG. 1, the clampers 24 and 25 are in an unclamped state, and the covered wire 21 pulled out from the wire winding body (not shown) passes between the clampers 24 and 25, and the capillary 2 has a center hole 2a. The coated wire 21 is supported by the capillary 2 through the capillary 2, and the tip 21a of the coated wire 21 projects from the capillary 2 by a distance l.

In this state, as shown in FIG. 3, the clampers 24 and 25 clamp the coated wire 21, and the electrode 6 moves to face the tip 21a of the coated wire 21.

The clampers 24 and 25 have clamp surfaces 24a,
The coated wire 21 is clamped between 25a.

The protrusions 26 to 29 break through the insulating coating 23 and come into contact with the wire body 22, and the clampers 24 and 25
is electrically connected to the coated wire 21 at four locations.

In this state, the discharge voltage generating circuit 5 is operated, and an arc discharge 30 occurs between the electrode 6 and the tip 21a of the covered wire 21, and the tip 21a of the covered wire 21 is melted, as shown in FIG. A ball 31 having a size two to three times the wire diameter of the covered wire is normally formed.

Thereafter, the wire bonding device 20 operates in the same manner as the conventional wire bonding device 1, and by using the balls 31, ball bonding is performed normally.

Furthermore, the clampers 24 and 25 are brought into the unclamped state again. The protrusions 26 to 29 are covered with an insulating coating 23
is only damaged locally, and a scar 3 remains on the insulating coating 23 of the coated wire 21 after the ball 29 is formed.
2-35 remains extremely small.

[0034] Therefore, the electrical insulation between the wires is not impaired in any way when the wires are bonded to the IC chip and wired.

Next, the features of the protrusions 26 to 28 will be explained. (2) As shown in FIG. 2, the protrusions 26 to 29 extend in a direction perpendicular to the covered wire 21 to be clamped.

Therefore, even if the covered wire 21 is deviated from a predetermined position, it will always bite into the insulating coating 23 as long as it is located within the clamping surfaces 24a, 25a. Therefore, the clampers 24, 25 and the wire main body 22 can be reliably electrically connected.

■Since two protrusions 26 to 29 are provided, electrical continuity between the clampers 24 and 25 and the wire body 22 is made at four locations, and the electrical continuity is reliable. It will be done.

(2) Since the protrusions 26 to 29 have a triangular cross section, the apex portions of the protrusions 26 to 29 reliably bite into the insulating coating 23.

■Since the height h of the protrusions 26 to 29 is set approximately equal to the thickness t of the insulating coating 23, the protrusions 2
6 to 29 do not cut into the wire body 22 excessively, and unnecessary damage to the wire body 22 can be avoided.

[0040]

As described above, according to the first aspect of the invention, ball bonding can be performed using a coated wire while minimizing damage to the coating.

According to the second aspect of the invention, even if the position of the covered wire on the clamper is shifted from the center, the clamper and the wire body can be electrically connected, and the formation of a ball is ensured. It can be done.

According to the third aspect of the invention, the clamper and the wire main body can be electrically connected at a plurality of locations, and the ball can be formed reliably.

According to the fourth aspect of the invention, the insulating properties of the protrusions are reliably bitten into the coating, and the electrical connection between the clamper and the wire body can be reliably established.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing essential parts of a wire bonding apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of the clamper in FIG. 1.

FIG. 3 is a diagram showing a state when forming a ball.

FIG. 4 is a diagram showing the state after the ball is formed.

FIG. 5 is a diagram showing a conventional example.

6 is a perspective view of the clamper in FIG. 5. FIG.

[Explanation of symbols]

2 Capillary 5 Discharge voltage generation circuit 6 Electrode 20 Wire bonding equipment 21 Coated wire 21a Tip 22 Wire body 23 Insulating coating 24, 25 Clamper 24a, 25a Clamp surface 26, 27, 28, 29 Projection part 30 Arc discharge 31 Ball 32-35 Scar

Claims (4)

[Claims] 1. A metal clamp (24, 25) that is electrically connected to the discharge voltage generation circuit (5) and clamps the wire, and a wire extending further from the clamper is passed through the inside. It consists of an insulating capillary (2) and an electrode (6) that is connected to the discharge voltage generating circuit and forms a ball by causing an arc discharge between it and the tip (21a) of the wire that protrudes from the capillary. In the wire bonding device, the clamper (24, 25) is
The clamp surfaces (24a, 25a) are provided with protrusions 26 to 29) large enough to bite into the insulating coating (23) of the wire and reach the wire body (22) during clamping. Characteristic wire bonding equipment. 2. A wire bonding apparatus according to claim 1, wherein the protrusion is a protrusion (26 to 29) extending on the clamping surface in a direction substantially orthogonal to the wire. . [Claim 3] The protruding portions (26 to 29) of claim 2 are:
A wire bonding device characterized in that a plurality of wire bonding devices are formed on the clamp surface (24a, 25a). [Claim 4] The protruding portions (26 to 29) of claim 2 are:
A wire bonding device characterized by a triangular cross section.