JP2000294595A - Wire bonding method - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a wire bonding apparatus capable of performing wire bonding without causing damage to a semiconductor element due to storage of a mounted component. A wire bonding apparatus for electrically connecting an external connection electrode of an electronic component mounted on a substrate and a circuit electrode of the substrate by a wire, wherein the wire bonding device is fed from a spool (14) and inserted into a capillary tool (13) for bonding. Clamper 1 for clamping the wire 15 to be cut
6 is electrically connected to the ground portion 21. As a result, the potential of the wire 15 at the time of bonding can be set to the ground potential, and the electric charge accumulated in the already mounted components such as a chip capacitor can be discharged to prevent breakage of the electronic component at the time of wire bonding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire bonding apparatus for electrically connecting external connection electrodes of a semiconductor element and circuit electrodes of a substrate by wires.

[0002]

2. Description of the Related Art Wire bonding is widely used as a method for electrically connecting a semiconductor element to a circuit electrode on a substrate. In this wire bonding, one end of a wire such as a gold wire is bonded to an external connection electrode of a semiconductor element by a capillary tool, and the wire in the bonded state is moved by a capillary tool to form a bond on a circuit electrode of a substrate. The wire is drawn to the point and bonded.

[0003]

By the way, the state of the substrate at the time of performing wire bonding to the semiconductor element mounted on the substrate is various, and when the surface mounting components other than the semiconductor element are already mounted, the wire is mounted. Bonding may be performed. In recent years, in order to improve the bonding property at the time of wire bonding, a plasma treatment is performed on the substrate surface prior to the wire bonding. In such a case, the electric charge is accumulated in the already mounted components, particularly in the electric storage components such as chip capacitors, by plasma processing.

If the above-mentioned bonding point is located on a circuit electrode electrically connected to the component in which the electric charge is stored, the following problem occurs. That is,
At the moment when one end of the wire connected to the semiconductor element is brought into contact with the wire bonding point, the electric charge accumulated in the mounted component flows to the semiconductor element via the wire. If the value of the current flowing at this time is excessive, the semiconductor element is damaged by the overcurrent. As described above, the conventional wire bonding apparatus has a problem that the semiconductor element is damaged at the time of wire bonding due to electric charges accumulated in the already mounted components.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wire bonding apparatus capable of performing wire bonding without causing damage to a semiconductor element due to charging of a mounted component.

[0006]

According to a first aspect of the present invention, there is provided a wire bonding apparatus for electrically connecting external connection electrodes of a semiconductor element mounted on a substrate and circuit electrodes of the substrate by wires. A wire supply unit for supplying a wire, a capillary tool for inserting the wire through the wire and pressing the wire to bond the wire to the external connection electrode and the circuit electrode; and a discharge unit for setting the potential of the wire to a ground potential. With.

A wire bonding apparatus according to a second aspect is the wire bonding apparatus according to the first aspect,
The discharging means is formed by electrically connecting a clamping means for clamping the wire to a ground portion.

[0008] A wire bonding apparatus according to a third aspect is the wire bonding apparatus according to the first aspect,
The discharging means is configured by electrically connecting a wire conducting portion that conducts with the wire in the wire supply portion to an earth portion.

A wire bonding apparatus according to a fourth aspect of the present invention is a wire bonding apparatus for electrically connecting an external connection electrode of a semiconductor element mounted on a substrate and a circuit electrode of the substrate with a wire, wherein the circuit of the substrate is provided. Discharging means for bringing the potential of the circuit electrode into the ground potential by contact with the electrode;

According to the present invention, by providing discharge means for setting the potential of the wire at the time of wire bonding or the potential of the circuit electrode of the substrate to the ground potential, the electric charge accumulated in the already mounted components is discharged to perform the wire bonding at the time of wire bonding. Electronic components can be prevented from being damaged.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. 1 is a perspective view of a wire bonding apparatus according to an embodiment of the present invention, FIG. 2 is a partial side view of the wire bonding apparatus, FIGS. 3 and 4 are explanatory views of the wire bonding operation, and FIG. FIG. 6 is a partial cross-sectional view of the wire bonding apparatus.

First, the overall structure of the wire bonding apparatus will be described with reference to FIG. On the upper surface of the base 1, a substrate 2
Is placed. A surface mount component such as a chip capacitor 4 is already mounted on the substrate 2, and a chip (semiconductor element) 3 to be wire-bonded is provided at the center of the substrate 2.
Is installed. A large number of circuit electrodes 5 serving as wire bonding points are formed around the chip 3. In the wire bonding, the external connection electrodes of the chip 3 and the circuit electrodes 5 are connected by wires. The circuit electrode 5 is electrically connected to the chip capacitor 4 which is a mounted component.
This substrate 2 has been subjected to plasma processing in a previous step prior to wire bonding, and electric charges are accumulated in the chip capacitor 4 by plasma processing.

A holding plate 6 is provided on the substrate 2. The holding plate 6 is connected to a rod 7 a of a cylinder 7. When the rod 7 a is pulled in, the substrate 2 is pressed and fixed by the holding plate 6. A movable table 10 is provided on the side of the base 1, and a drive box 11 is provided on the movable table 10. A horn 12 extends forward from the drive box 11, and a capillary tool 13 is held at a tip of the horn 12.

A wire 15 used for wire bonding is inserted into the capillary tool 13. Wire 15
Is supplied in a state of being wound on a spool 14 serving as a wire supply unit. The wire 15 fed from the spool 14 passes through the tension application unit 17 and the cut clamper 16 and is inserted into the capillary tool 13. The cut clamper 16 performs opening and closing operations to clamp and fix the wire 15. That is, the cut clamper 16 is a clamping means for clamping the wire. Capillary tool 1
A torch 19 is arranged near the lower end of the third torch 19.
The torch 19 forms a metal ball at the lower end of the wire 15 by generating a spark between the torch 19 and the wire 15 protruding from the lower end of the capillary tool 13.

X direction motor 10X and Y direction motor 10Y
Is driven to move the movable table 10, the drive box 11, the horn 12, the capillary tool 13 and the like on the movable table 10 move horizontally in the X direction and the Y direction. The capillary tool 13 is housed in the drive box 11 and driven up and down by a Z-direction motor (not shown).

As shown in FIG. 2, the cut clamper 6 is electrically connected to the grounding portion 21. When the cut clamper 6 is closed and the wire 15 is clamped, each portion connected to the wire 15 is connected to the wire 15. The transferred electric charges are discharged to the ground portion 21, and the potential of the wire 15 becomes the ground potential. Therefore, the cut clamper 16 and the grounding portion 21 serve as discharging means for setting the potential of the wire 15 to the ground potential. The discharging means may be such that the potential of the wire 15 is brought into contact with the wire 15 drawn out from the spool 14 and the potential of the wire 15 is set to the ground potential.
Is more preferable because the electrical connection with the wire 15 can be ensured.

This wire bonding apparatus has the above configuration, and its operation will be described below with reference to FIGS. 3 (a) to 3 (c) and FIG. 4 (a)
(C) shows a series of operations in the order of operation. FIG.
(A) is an initial state. In this state, the wire 15 is led out from the lower end of the capillary tool 13 and the wire 15 is clamped by the clamper 16 above the capillary tool 13 to fix the wire 15. . Reference numeral 15 'denotes a wire connecting the chip 3 and the substrate 2 in the previous wire bonding operation.

Next, as shown in FIG.
By applying a high voltage to the torch 19 approaching the lower end of the wire 15, an electric spark is generated between the lower end of the wire 15 and the tip of the torch 19, and the ball 20 is formed at the lower end of the wire 15. .

Next, as shown in FIG.
6, the wire 15 is released from the clamped state, and the capillary tool 13 is lowered to press the ball 20 against the external connection electrode on the upper surface of the chip 3 for bonding. Next, as shown in FIG. 4A, the capillary tool 13 is raised, and when the capillary tool 13 reaches the highest point, the cut clamper 16 is closed. Then, in this state, the capillary tool 13 is moved above the circuit electrode 5 of the substrate 2, and the lower end of the capillary tool 13 is lowered while drawing a predetermined trajectory to form a loop of the wire 15, and FIG. The wire 15 is pressed against the circuit electrode 5 of the substrate 2 for bonding as shown in FIG.

Next, when the capillary tool 13 is raised and the wire 15 clamped by the cut clamper 16 is pulled up, the wire 15 is cut at the bonding point a. This completes the bonding at one bonding point, and then the same wire bonding operation is repeated for each bonding point.

In the above bonding operation, FIG.
At the time of bonding the substrate 2 to the circuit electrode 5 shown in (b), the wire 15 is in a state of being electrically connected to the ground portion 21 by being clamped by the cut clamper 16.
For this reason, even if the electric charge is accumulated in the already mounted components such as the chip capacitor 4, the electric charge is discharged to the ground portion 21 via the cut clamper 16. Therefore, the charge accumulated via the wire 15 during bonding does not flow to the chip 3, and the chip 3 is not damaged by an overcurrent.

Instead of conducting the wire 15 to the ground portion 21 by clamping the wire 15 with the cut clamp 16, the spool 14 may be set to the ground potential as shown in FIG. In the example shown in FIG. 5, a wire 15 is connected to the inner surface of the metal annular member 14 a of the spool 14 so as to be in conduction with the wire 15, and the brush 14 is electrically connected to the ground portion 21 on the inner surface of the metal annular member 14 a.
b. That is, the metal annular member 14a is a wire conducting portion, and since the wire 15 is always in conduction with the grounding portion 21 by connecting the wire conducting portion to the grounding portion 21, other wires already mounted on the chip 3 at the time of wire bonding. The electric charge stored in the component does not flow.

Further, instead of setting the electrons of the wires 15 to the ground potential, a holding plate 6 for holding the substrate 2 may be connected to the ground portion 21 as shown in FIG. That is, by pressing the substrate 2 with the pressing plate 6 prior to the wire bonding, the contact portion 6a on the lower surface of the pressing plate 6 comes into contact with the circuit electrode 5 of the substrate 2 to conduct, and the circuit electrode 5 itself is grounded. To conduct. Therefore, the holding plate 6 and the grounding portion 21 serve as discharging means for setting the potential of the circuit electrode 5 to the ground potential. As a result, the electric charges accumulated in the already mounted components are discharged to the ground portion 21 prior to the wire bonding, and the chip 3 is not damaged by an overcurrent during the wire bonding.

[0024]

According to the present invention, since the discharging means for setting the potential of the wire at the time of wire bonding or the potential of the circuit electrode of the substrate to the ground potential is provided, the electric charges accumulated in the already mounted components are discharged to discharge the wire. Damage to electronic components during bonding can be prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view of a wire bonding apparatus according to an embodiment of the present invention.

FIG. 2 is a partial side view of the wire bonding apparatus according to the embodiment of the present invention;

FIG. 3 is an explanatory diagram of a wire bonding operation according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a wire bonding operation according to an embodiment of the present invention.

FIG. 5 is a partial side view of the wire bonding apparatus according to the embodiment of the present invention;

FIG. 6 is a partial sectional view of the wire bonding apparatus according to one embodiment of the present invention;

[Explanation of symbols]

 2 Substrate 3 Chip 4 Chip capacitor 5 Circuit electrode 6 Holding plate 10 Moving table 12 Horn 13 Capillary tool 14 Spool 15 Wire 16 Cut clamper 21 Grounding part

Claims (4)

[Claims] 1. A wire bonding apparatus for electrically connecting an external connection electrode of a semiconductor element mounted on a substrate and a circuit electrode of the substrate by a wire, the wire supplying unit supplying the wire, and the wire passing therethrough. A wire bonding apparatus comprising: a capillary tool for bonding a wire to the external connection electrode and the circuit electrode by pressing the wire; and discharging means for setting the potential of the wire to a ground potential. 2. The wire bonding apparatus according to claim 1, wherein said discharging means is configured to electrically connect a clamping means for clamping said wire to a ground portion. 3. The wire bonding apparatus according to claim 1, wherein said discharging means electrically connects a wire conducting portion in said wire supply portion to said wire with a ground portion. 4. A wire bonding apparatus for electrically connecting an external connection electrode of a semiconductor element mounted on a substrate and a circuit electrode of the substrate by a wire, wherein the wire bonding device contacts the circuit electrode of the substrate, A wire bonding apparatus comprising: discharge means for setting a potential of a circuit electrode to a ground potential.