JPS63257237A - Wire bonding - Google Patents

Abstract

PURPOSE:To stabilize a wire loop and to prevent a short circuit at an edge and a bend by moving a capillary in such a way that the tension is exerted on the wire loop just before a bonding point. CONSTITUTION:After a capillary 4 has bonded a wire 2 to a first bonding point a, it is lifted, passes through a highest rise point b and then descends; the capillary 4 stops descending once at a prior point c and is shifted horizontally to an upper point d; after that, it descends again and bonds the wire 2 to a second bonding point e. If the capillary 4 is shifted according to this locus, the tension is exerted on a wire loop 7; a curved point on the side of the capillary 4 is shifted from A to B; accordingly, it is possible to prevent a short circuit at an edge irrespective of a bonding distance and a type of a semiconductor device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wire bonding method using a wire bonding apparatus.

[Conventional technology]

Wire bonding is performed, for example, as shown in Figures 3a to 3 (see Japanese Patent Laid-Open No. 57-87143). In other words, the electrode (1) connects the tip of the wire (2) with the ball (3) to the capillary (4) which is the first bonding point to the semiconductor chip (5).
3b) and the wire (2).
The capillary (4) rises as it moves forward (Fig. 3c), and further rises as it moves in the XX direction.
15), then move downward while pulling in the wire (2) (Fig. 3θ), and further descend to contact the wire (2) with the lead (6) (Fig. 3) to form a wire loop (7). and connect the wire (2) to the lead (6) into the capillary (4).
) to the second bonding point.
The wire was pulled and cut using a clamper (not shown), and then raised again (Fig. 3h) to prepare for the next bonding process.

[Problem that the invention seeks to solve]

However, as shown in Figure 3+L-f, the wire (2) deforms into an S-shape between the capillary (4) and the first bonding point, so the wire (2) deforms into an S-shape as shown in Figure 36.
) as it descends, the frictional resistance against the wire passing through the tip of the capillary (4) increases due to the deformation of the wire, and the wire (2) is pulled above the capillary (4) and becomes 5mm thick, as shown in Figure 3f. As shown, the curved part (N) of the wire contacts the lead (6) before the capillary (4), and as the capillary (4) descends, the contact point becomes the second contact point.
It moves towards the bonding point and is crimped.

As the bonding distance from the first bonding point to the second bonding point increases, the curve of the wire (A) increases.
If the contact point with the lead is far away from the second bonding point due to large
As shown in figure a, there may be an edge short (S) with the semiconductor chip (5) or the die pad part (8) to which the semiconductor chip (5) is attached, or even if it is not so extreme, there may be an edge short as shown in figure 4b. A similar problem occurs when the second bonding point must be placed near the edge of the lead due to the type of semiconductor device. As the length of the wire increases, the wire loop (7) formed becomes unstable, and the wire bends due to the stress applied during bonding or the original habit of the wire, causing the wire to bend when adjacent to it. Problems such as contact with other wires also occurred.

This invention was made to solve the above problems.
The present invention aims to provide a wire bonding method that can obtain a stable wire loop regardless of the bonding distance, type of semiconductor device, etc.

[Means for solving problems]

The wire bonding method according to the present invention is such that the descending of the capillary is temporarily stopped or decelerated before the second bonding point, and the wire is drawn to draw a trajectory in which the wire is pulled in the XY direction.0 [Operation] This invention In the second wire bonding method, the capillary is pulled in the same direction in the X and Y directions before the second bonding point, thereby applying tension to the wire and preventing edge shorts and bending of the wire. can be prevented, and the reliability of wire bonding is improved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1F. As shown in Fig. 1a, the capillary (4), after bonding the wire (2) to the first bonding point (a), moves upward, passes through the highest point (b), and then descends. At point (C), the cavity (4) once stopped descending, moved horizontally to the upper point (=J), and then descended again.
Bonding point (e) Bond the wire (2).

Cab with a trajectory like this: 8. By moving the capillary (4), tension is applied to the wire loop (7), and the dot on the capillary (4) side moves from (A) to (B), depending on the bonding distance and the type of semiconductor device. In addition to preventing edge shorts, the wire loop (7) is stabilized, preventing wire loop bending, and bonding reliability is improved.

In the above embodiment, the descending of the capillary (4) was temporarily stopped before the second bonding point and the capillary (4) was moved horizontally, but as shown in FIG. The same one may be placed at the two bonding points and lowered diagonally.

Further, it goes without saying that the trajectory from the first frame to the e-cutting point ζ in FIG. 2 is not limited to the trajectory shown in the figure.

〔Effect of the invention〕

As described above, according to the present invention, the capillary is moved to apply tension to the wire loop before the second bonding point, so the wire loop is stabilized, edge shorts and bends can be prevented, and wire bonding is reliable. Same gender.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a wire bonding method according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing another embodiment of the invention, and FIG. 3 is an explanatory diagram showing a conventional wire bonding method. FIG. 4 is an explanatory diagram showing a wire loop failure. In Figure 1, (2) is a wire, (4) is a capillary,
(5) is the semiconductor chip, (6) is the lead, (a) is the first
Bonding points, (c) shows the front point, and (e) shows the second bonding point. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent: Masuo Oiwa, Patent Attorney Figure 1 Figure 2 @Figure 1 Figure 4 (a)
(b) S11-noji° short

Claims (1)

[Claims] (1) In a wire body that is placed on a table movable in the XY directions and connects the wires between two points using a capillary through which the wire penetrates inside and is movable in the Z direction, the wire is connected to the first bonding point. After connecting the capillary, the capillary rises and falls in the Z direction and moves in the XY direction, and before reaching the second bonding point, the capillary's descent is temporarily stopped or decelerated, and the wire is pulled in the XY direction. A wire bonding method comprising drawing a wire and connecting the wire to a second bonding point.