JPH03263842A - Wire bonding - Google Patents

Abstract

PURPOSE:To form a loop of an excellent shape having a sufficient height with high operability by bonding the lower ends of wires to a semiconductor chip, then raising a capillary in a circularly bent state in an opposite direction to a loop forming direction, then moving the forming direction and bonding the wires to the electrodes of a board. CONSTITUTION:In a wire bonding method for leading wires 3 wound on a spool from the lower end of a capillary 11 and connecting a semiconductor chip 15 to the electrodes of a board 14 via the wires 3, the capillary 11 is moved down on the chip 15, the lower ends of the wires 3 are bonded to the chip 15, the capillary 11 is then raised in a circularly bent state in an opposite direction N1 to a loop forming direction, then moved to a loop forming direction N2 and the wires 3 are bonded to the electrodes of the board 14. Thus, the wire bonding can be performed while forming the loop of the wire of an excellent shape having a sufficient height, and the moving stroke of the capillary can be shortened. Accordingly, its operating efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a wire bonding method, and more particularly to a method for controlling the loop shape of a wire led out from the lower end of a capillary.

(Prior art) A wire bonder that connects a semiconductor chip to an electrode on a board such as a lead frame on which the semiconductor chip is mounted uses a wire like an ultra-thin gold wire wound around a spool.
While clamping the wire with a clamper and inserting it into the capillary, the wire is led out from the lower end of the capillary, the electrode is brought close to the lower end of the wire, an electric spark forms a molten ball, and then the wire is inserted into the capillary. It connects the semiconductor chip and the electrodes of the substrate.

In such wire bonding means,
As shown in Japanese Patent No. 47893, the capillary is lowered onto the semiconductor chip to bond the lower end of the wire to the semiconductor chip, and then the capillary is raised vertically and then moved in the opposite direction to the loop forming direction. It has been proposed to connect the wire to the electrode of the substrate by moving it in the direction of loop formation.

(Issue 8 to be solved by the invention) Although the above conventional means has the advantage of making the loop height sufficiently high and improving the loop shape, the capillary is raised vertically and then in the opposite direction to the loop forming direction. Since the capillary is first moved in the direction of loop formation and then moved in the loop forming direction, the locus of the capillary is complicated and the movement stroke is also quite long, resulting in a problem of reduced work efficiency.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a wire bonding method that can solve the problems of the conventional methods described above.

(Means for Solving the Problems) For this purpose, the present invention provides a wire bonding method in which a wire wound around a spool is led out from the lower end of a capillary, and this wire connects a semiconductor chip and an electrode on a substrate. , the capillary is lowered onto the semiconductor chip to bond the lower end of the wire to the semiconductor chip, and then the capillary is raised in a circular shape in a direction opposite to the direction of the loop-forming force, and then moved in the direction of the loop-forming force. Then, the wire is bonded to the electrode of the substrate.

(Function) In the above configuration, the capillary with the lower end of the wire bonded to the semiconductor chip rises in a circular shape in the opposite direction to the loop formation direction, and then moves in the loop formation direction to bond the wire to the electrode of the substrate. Therefore, the base end of the wire rises substantially perpendicularly from the semiconductor chip, and a well-shaped loop having sufficient height can be formed with good workability.

(Example) Next, the present invention will be described in detail with reference to the drawings.

Fig. 1 shows the head part A of the wire bonder, and 1 is a frame that is the main component to the head part, and various members and parts described below are integrally assembled to this frame 1. . A spool 2 is pivotally attached to the frame 1, and a very thin wire 3 such as a gold wire is wound around the spool. 4 is a morph, which rotates the spool 2 and draws out the wire 3. At this time, the wire 3 is led out in the tangential direction N of the spool 2 so that the wire 3 is not twisted.

5 is a tension clamper installed below the frame 1; 6 is a cut clamper installed below the tension clamper 5, and each is attached to the frame 1 via an insulating material 7. Reference numeral 8.9 denotes a pad attached to the clamper 5.degree. 6, and the wire 3 is clamped by opening and closing this pad 8.9.

Reference numeral 11 denotes a long cylindrical capillary provided below the cut clamper 6, and a horn 1 protruding from the frame 1.
It is held at the tip of 2. A torch electrode 16 approaches the lower end of the wire 3 leading out from the capillary 11 and forms a molten ball 17 at the lower end of the wire 3 by an electric spark. 13 is a camera mounted on the upper part of the frame 1, and 18 is its lens barrel, which observes the bonding point below the capillary 11. 14 is a substrate such as a lead frame, and 15 is a semiconductor chip mounted on the substrate 14. As will be described in detail later, the electrodes of the substrate 14 and the electrodes of the semiconductor chip 15 are connected by wires 3.

21 is an air blowing section provided between the spool 2 and the tension clamper 5; 20 is a tube for sending air from an air supply device (not shown) to the air blowing section 21; and 22 and 22 are provided upright on the air blowing section 21. This is a guide for the wire 3. The air blowing section 21 applies desired tension to the wire 3 by blowing air onto the wire 3.

This apparatus has the above-mentioned configuration, and its operation will be explained next with reference to FIG.

Initially, the head part A is located above the substrate 14, and at this position, the torch electrode 16 is brought close to the lower end of the wire 3 led out from the capillary 11, a high voltage is applied to the torch electrode 16, and the wire 3 is A molten ball 17 is formed at the lower end (FIG. 2(a)).

Next, the capillary 11 is lowered, and the ball-F lands on the electrode on the semiconductor chip 15 for bonding (FIG. 2(b)). At this time, ultrasonic waves are transmitted from a US oscillator (not shown) to the horn 12 to promote bonding of the ball 17.

Next, the capillary 11 is raised in a circular shape in the direction opposite to the loop forming direction (arrow Nl) (see figure (C)), and then moved in an arch shape in the loop forming direction (arrow N2), and the wire 3 is The wire 3 is pressed against the substrate 14 and bonded to the electrode of the substrate 14 (FIG. 1(d)), and then the wire 3 is canted from the bonding point by being clamped and pulled up by the cut clamper 6, and then the wire 3 is canted from the bonding point, and then the capillary 11 is ((e) in the same figure).

As described above, the semiconductor chip 15 and the substrate 14 are connected by the wire 3, but as described above, the capillary 11
If the wire 3 is raised in a circular shape in the direction N1 opposite to the loop formation direction, it is possible to form a loop having a sufficient height and a good shape while applying tension to the wire 3 in the direction opposite to the loop formation direction. Moreover, the movement stroke of the capillary 11 is shorter than that of the conventional means, and wire bonding can be performed with high work efficiency.

In particular, if the capillary 11 is raised in a circular shape so as to be tangential to the vertical line M at the bonding point, the rising portion 3a of the wire 3 will be made substantially vertical, and the wire 3 will be raised from the electrode on the semiconductor chip 15. This prevents the wire from coming off and allows the wire 3 to be securely bonded to the semiconductor chip 15.

(Effects of the Invention) As explained above, the present invention provides a wire bonding method in which a wire wound around a spool is led out from the lower end of a capillary, and this wire connects a semiconductor chip and an electrode of a substrate. is lowered onto the semiconductor chip to bond the lower end of the wire to the semiconductor chip, the capillary is raised in a circular shape in the opposite direction to the loop formation direction, and then moved in the loop formation direction to bond the wire to the semiconductor chip. of! Since bonding is done to the +& electrodes, wire bonding can be performed while forming a well-shaped wire loop with sufficient height, and the moving stroke of the capillary can be shortened, increasing work efficiency.
Furthermore, by making the rising portion of the wire bonded to the semiconductor chip substantially vertical, the wire can be firmly bonded to the semiconductor chip.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 2 is a side view of the head portion of the wire bonder, Fig. 2(a) and Fig. 2(b).
, (c), (d), and (e) are front views of main parts during bonding work. 2...Spool 3...Wire 11...Capillary 14...Substrate 15...Semiconductor chip

Claims (1)

[Claims] A wire bonding method in which a wire wound around a spool is led out from the lower end of a capillary, and the wire is used to connect a semiconductor chip to an electrode on a substrate, wherein the capillary is lowered onto the semiconductor chip. After bonding the lower end of the wire to the semiconductor chip, the capillary is raised in a circular shape in the opposite direction to the loop formation direction, and then moved in the loop formation direction to bond the wire to the electrode of the substrate. A wire bonding method characterized by: