JPS63182829A - Bonding device and spool used therefor - Google Patents

Abstract

PURPOSE:To perform a ball bonding work with certainty by connecting the metal wire on the end parts of the covered wire both on the side where the wire is fed to a bonding part and on the opposite side are connected to the reference potential. CONSTITUTION:A covered wire 2, consisting of a metal wire covered by an insulating material, is fed to a bonding part. At that time, a connecting terminal 1A to be used to connect to the reference potential GND is provided on a spool 1. The metal wire of the starting of winding of the wire 2 is connected to the connecting terminal 1A, and the metal wire is connected to the potential GND through a spool holder 8 and the like. As a result, the arc is generated excellently when a ball is formed, and the ball is formed at the tip on the feeding side of the wire 2. Accordingly, the charge-up of electric charge on the stray capacitance of the wire 2 can be prevented. As a result, the ball bonding operation can be performed with certainty.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to wire bonding technology, and in particular to a technology that is effective when applied to wire bonding technology that uses a coated wire whose metal wire surface is coated with an insulator. It is related to.

[Prior art]

Wires are used to connect semiconductor chips and leads of resin-sealed semiconductor devices. The wires are connected using a wire bonding device.

The wire is wound around a spool attached to a bonding device, and is supplied from this spool to a bonding part through a tensioner, a wire clamper, a bonding tool, etc.

The bonding device is configured to connect a wire with a ball formed at the tip end on the supply side to an external terminal (bonding pad) of the semiconductor chip, and then connect a predetermined length of the wire at the rear end side to the lead. This type of bonding method is called a so-called ball bonding method. The ball at the tip of the supply side of the wire is formed by bringing an arc electrode close to each other and generating an arc.

There is a tendency for coated wires to be used as the wires. The coated wire is a metal wire made of gold, Cu, etc. whose surface is coated with an insulator such as urethane resin, polyimide resin, or metal oxide film. When this coated wire is sealed with resin,
A feature of this method is that poor contact between wires and poor contact between wires and semiconductor chips can be prevented.

Regarding the coated wire, for example, JP-A-61-1
It is described in Publication No. 94735.

[Problem that the invention seeks to solve]

However, as a result of the above-mentioned coated wire bonding test and study thereof, the inventor found that the following problem occurred.

Since the surface of the metal wire of the coated wire is covered with an insulator, it cannot be grounded (reference potential, e.g. O [V]) in the supply path of the spool. Therefore, the supply side of the coated wire When forming a ball at the tip of the ball, it is difficult to generate an arc and it is not possible to form a sufficient ball, making ball bonding impossible.

Further, as described above, since the metal wire of the covered wire cannot be grounded, when a ball is formed at the tip end of the covered wire on the supply side, the stray capacitance of the covered wire is charged up. Therefore, when the coated wire is connected to the external terminal of the semiconductor chip, the electric charge of the stray capacitance is discharged.

Electrostatic damage occurs in the input/output circuits of semiconductor chips.

An object of the present invention is to provide a technique that can reliably perform pole bonding in a bonding technique using coated wire.

Another object of the present invention is to provide a technique that can prevent electrostatic damage from occurring in a semiconductor device in a bonding technique using covered wire.

Another object of the present invention is to provide a bonding device capable of achieving each of the above objects.

Another object of the present invention is to provide a spool that can achieve each of the above objects.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

A brief overview of typical inventions disclosed in this application is as follows.

In a bonding apparatus using a coated wire, an end of the coated wire opposite to the supply side is connected to a reference potential.

In addition, in the spool around which the coated wire is wound, a connection terminal for connecting to a reference potential is provided on the spool, or an aluminum body from which the alumite surface treatment has been partially removed is used as a connection terminal, and the coated wire is attached to that part. Connect the metal wire with the coating film removed from the winding start end.

[Effect]

According to the above-mentioned means, since the metal wire of the covered wire can be brought to a reference potential, it is possible to improve arc generation when forming a ball and to form a ball reliably at the tip of the supply side of the covered wire. can. Furthermore, since the covered wire can be set at a reference potential, it is possible to prevent charges from being charged up in the stray capacitance of the covered wire.

Hereinafter, the configuration of the present invention will be explained along with examples.

In addition, in all the figures for explaining the embodiment, parts having the same functions are given the same reference numerals, and repeated explanations thereof will be omitted.

[Embodiment of the invention■]

FIG. 1 (schematic configuration diagram) shows a bonding apparatus which is Embodiment 2 of the present invention.

The bonding device has a spool 1 as shown in FIG.
It is arranged to supply the coated wire 2 wound around the bonding part 3 to the bonding part 3. The coated wire 2 is supplied by a tensile eye 4, a wire guide member 5, and a wire clamper 6.
, bonding tools are supplied to the bonding part 3 through each of the bonding tools.

In the bonding portion 3, a resin-sealed semiconductor device 12, which is configured as shown in FIG. 2 (cross-sectional view) and FIG. 3 (main part cross-sectional view), is arranged before being resin-sealed. The resin-sealed semiconductor device 12 is configured by resin-sealing a semiconductor chip 12A mounted on a tab portion 12C via a connecting metal film 12B and an inner lead portion of a lead 12D with a resin sealing member 12E. has been done.

The semiconductor chip 12A and the leads 12D are connected by the covered wire 2. One end of the covered wire 2 is an external terminal (bonding pad) 12Aa exposed from an opening in the passivation film 12Ab of the semiconductor chip 12A.
It is connected to the. The other part of the coated wire 2 is a lead 12.
It is connected to the inner lead part of D.

As shown in detail in FIG. 3, the covered wire 2 is constructed by covering the surface of a metal wire 2A with an insulator 2B.

The metal wire 2A is made of, for example, gold (Au), copper (Cu), aluminum (Al1), or the like. The insulator 2B is made of, for example, urethane resin, polyimide resin, metal oxide film (CuO
, Cu, ○, Affi, 02).

A ball 2Aa is formed at the tip of the supply side of the coated wire 2, which is located at the tip of the bonding tool 7. The ball 2Aa is formed by an arc electrode 10 provided close to the bonding tool 7. That is, the ball 2Aa is formed by generating an arc between the metal wire 2A at the supply side tip of the coated wire 2 and the arc electrode 10. The arc electrode 10 is
6 connected to the arc generating circuit 11 The arc generating circuit 11 mainly includes a capacitor C1, a storage capacitor C2, a thyristor D operated by a trigger, and a resistor R. DC is a direct current power supply that supplies a voltage of several thousand [V], and GND is a reference potential (for example, ground potential =
O [V]), Vlt is a voltmeter, and A is an ammeter.

The spool 1 around which the covered wire 2 is wound is, for example, as shown in FIGS. 1 and 4 (perspective views of main parts).
Constructed by applying alumite treatment to the surface of aluminum metal. The alumite treatment is performed to improve mechanical strength and prevent the occurrence of scratches. As described above, this spool L has insulation properties because it has been alumite treated.

The spool 1 is attached to a spool holder 8,
The spool holder 8 is attached to the main body 9 of the bonding device by a rotating shaft 8A.

The spool holder 8 is made of, for example, stainless steel so that at least a portion thereof is conductive.

In the bonding device configured as described above, as shown in FIGS. 4 and 5 (enlarged perspective views of main parts), the spool 1 is provided with a connection terminal IA. The connection terminal IA is provided in a dot shape on the side surface portion (flange portion) of the spool 1 that contacts the conductive portion of the spool holder 8 .

As shown in FIG. 5, the connection terminal IA is constructed by providing a conductor IAb on top of an insulator IAa and a connection metal portion IAc on top of the conductor IAb. Insulator IA
A is electrically isolated from the spool 1 and is formed of, for example, polyimide resin so as to have appropriate elasticity so that the connecting metal part IAc can reliably abut against the spool holder 8.

The conductor IAb is formed of, for example, Cu foil so that the connection metal part IAc that connects the two metal wires of the covered wire 2 and the connection metal part IAc that contacts the spool holder 8 can be reliably connected. . The metal connection portion IAc is formed using conductive paste, solder, adhesive tape, or the like.

A metal wire 2A of the end of the covered wire 2 on the opposite side to the side to be supplied to the bonding part 3 is inserted into the connection terminal IA through a notch formed in the side surface (flange) of the spool 1.
That is, it is configured to connect the metal wire 2A at the winding start end of the coated wire 2. This metal wire 2A is connected by the connection metal portion IAc of the connection terminal IA.

Insulator 2 on the surface of metal wire 2A at the beginning of winding of coated wire 2
B is removed by heating or chemically. The connection terminal IA, that is, the metal wire 2A of the coated wire 2 is connected to the reference potential GND through the spool holder 8, its rotating shaft 8A, and the main body 9. The reference potential GND is.

This potential is similar to the reference potential GND of the arc generating circuit 11.

In this way, the spool 1 is provided with a connection terminal IA for connecting to the reference potential GND, and by connecting the gold FitIi 12A at the winding start end of the coated wire 2 to this connection terminal, the reference potential can be connected to the reference potential GND through the spool holder 8, etc. Potential GN
Since it can be connected to D, the metal l of coated wire 2
12A can be connected to reference potential GND.

Further, the two metal wires of the covered wire 2 can be connected to the reference potential GND by simply connecting the metal wire 2A at the winding start end of the covered wire 2 to the connecting terminal IA of the spool 1. The work for connecting the metal wire 2A to the reference potential GND can be simplified.

Further, in the bonding apparatus using the spool 1 having the connection terminal IA, since the metal wire 2A of the covered wire 2 is connected to the reference potential GND, when forming the ball,
Since a sufficient potential difference between the arc electrode 10 and the metal wire 2A of the coated wire 2 on the supply side can be ensured and good arc generation can be achieved, the metal wire 2A at the tip of the coated wire 2 on the supply side A ball can be reliably formed.

Further, since the metal wire 2A of the covered wire 2 can be set to the reference potential GND, it is possible to prevent charges from being charged up in the stray capacitance of the metal wire 2A of the covered wire 2. In other words, the external terminal 12A of the semiconductor chip 12A
When first bonding is performed to connect the metal wire 2A at the tip of the supply side of the coated wire 2 with a ball formed thereon, it is possible to prevent excessive voltage from flowing into the input/output circuit of the semiconductor chip 12A, thereby reducing static electricity. Destruction can be prevented.

In addition, the above-mentioned coated wire 2 may be colored in order to clarify whether or not the insulator 2B is present on the surface of the two metal wires.

[Example of the invention■]

This embodiment (2) is another embodiment of the present invention in which the shape of the connection terminal provided on the spool is changed.

FIG. 6 (a perspective view of the main parts) shows a spool used in a bonding apparatus which is Embodiment (2) of the present invention.

As shown in FIG. 6, the spool 1 of this embodiment (2) is provided with a ring-shaped connection terminal IA on its side surface. Even if the spool 1 rotates, this connection terminal IA
The structure is such that the metal wire 2A of the covered wire 2 can be reliably connected to the reference potential GND through the connection member 9A to the reference potential GND.

In this way, by providing the ring-shaped connection terminal IA on the spool 1, substantially the same effects as in Example I can be obtained.

[Embodiment of the invention■]

The spool of this embodiment replaces the terminal IA in FIG.
As a result of removing the alumite surface treatment on this part, the aluminum body whose surface is exposed is used as a branch terminal. That is, in a spool where the entire surface of the aluminum body is anodized, a part of the alumite on the outside of the side wall of the spool is removed to expose the surface of the aluminum body, and the exposed aluminum layer area is covered with the metal wire of the covering wire. The spool serves as a connection terminal for connection to a reference potential, and is characterized in that a metal wire from which the coating film at the winding start end of the coated wire has been removed is connected to the connection terminal.

Note that the connection terminal has a dot shape, a ring shape, or the like. Therefore, this spool can produce substantially the same effect as the spool of the embodiment (2).

As above, the invention made by the present inventor has been specifically explained based on the above embodiments. However, the present invention is not limited to the above embodiments, and can be modified in various ways without departing from the gist thereof. Of course.

For example, in the present invention, the reference potential GND is not necessarily set to 0 [0] by changing the voltage applied to the arc electrode 10.
v].

The invention can also be applied to ultrasonic bonding techniques using coated wires.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

On the spool around which the covered wire is wound, the metal wire of the covered wire can be connected to a reference potential.

In a bonding device using coated wire, pole bonding can be performed reliably, and electrostatic damage to semiconductor devices can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a bonding apparatus which is Embodiment 2 of the present invention. FIG. 2 is a sectional view of a semiconductor device placed in the bonding device, FIG. 3 is a sectional view of a main part of the semiconductor device, and FIG. 4 is a perspective view of a main part of a spool provided in the bonding device. , FIG. 5 is an enlarged perspective view of the main part of the spool, and FIG.
FIG. 2 is a perspective view of a main part of a spool used in a bonding device according to embodiment (2) of the present invention. In the diagram, 1... Spool, IA... Connection terminal, 2...
・Coated wire, 2A...metal wire, 2B...insulator,
10... Arc electrode, 11... Arc generation circuit, 1
2...Semiconductor device, 12A...Semiconductor chip, 12
0...Lead, GND...Reference potential. Figure 1 Figure 1 Figure 1

Claims (1)

[Claims] 1. In a bonding device that supplies a coated wire whose surface is coated with an insulator to a bonding part, the metal wire at the end of the coated wire on the opposite side to the side supplied to the bonding part. A bonding device characterized in that: is connected to a reference potential. 2. The coated wire is wound around a spool, and the metal wire at the end of the coated wire is connected to a reference potential via a connection terminal provided on the spool. A bonding device according to scope 1. 3. An arc electrode for forming the metal wire at the tip of the coated wire into a ball is provided at a position close to the tip of the coated wire on the side that is supplied to the bonding part. A bonding device according to scope 1 or 2. 4. In a spool for a bonding device in which a coated wire whose surface is coated with an insulator is wound, a connection terminal for connecting the metal wire of the coated wire to a reference potential is provided, and the connection terminal is provided with a connection terminal for connecting the metal wire of the coated wire to a reference potential. A spool characterized in that a metal wire is connected to which the coating film at the winding start end of the coated wire has been removed. 5. The spool according to claim 4, wherein the connection terminal has a dot shape, a ring shape, or the like. 6. In a spool where the entire surface of the aluminum body is anodized, a part of the alumite on the outside of the side wall of the spool is removed to expose the surface of the aluminum body, and the exposed aluminum layer area is coated with the metal wire of the covering wire. 1. A spool, which serves as a connection terminal for connection to a reference potential, and is characterized in that a metal wire from which the coating film at the winding start end of the coated wire has been removed is connected to the connection terminal. 7. The spool according to claim 6, wherein the connection terminal has a dot shape, a ring shape, or the like.