JPS6083342A - Wire bonding method - Google Patents

Abstract

PURPOSE:To form a stable wire loop by bonding a wire with a pellet, moving a bonding tool while applying tension to the bonding wire by the flow of air and stopping the operation of the fall of the bonding tool once at a predetermined position. CONSTITUTION:A bonding device consists of a wire delivery section 1, an upper clamp 3, a lower clamp 4, a bonding tool 5, and a tension applying mechanism 10, which can apply tension to a bonding wire 7 by air flowing in a tube body 11. The mechanism 10 is operated from a wire loop forming starting stage after a ball 13 is bonded with a pellet 8, and fixed tension is applied to the wire 7. When the movement of the tool 5 is stopped in a region on its midway of the operation of the fall of the tool 5, sag, which may be generated due to friction, can also be removed because tension by the flow of air is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a wire binding method for connecting semiconductor components.

[Technical background of the invention and its problems]

In the assembly process of semiconductor devices, binding wires such as gold wires and aluminum wires are used to connect both pellets, which are semiconductor components, and lead frames.

In general, for such bonding, as shown in FIG.
A wire binding method is used in which a lower clamper c'r that can be moved up and down is arranged in this order, and a bending tool d that moves up and down together with the lower clamper C is placed below the lower clamper C.

The bonding method is as follows: 1 upper clamper bs lower clamp/4 c 'a
- After introducing the bonding wire into the bonding tool d, form a gale gt on the tip of the bonding wire e with a torch f. From this state, Figure 2 (B
) has traditionally been carried out along the progression shown in Here, the clamping at the upper clamp +b is performed with enough force to apply tension to the bonding wire e, and the lower clamp e
c clamps the bonding wire e with a force stronger than the force of the upper clamp/fb to restrain its movement.

That is, from the state where the bonding wire e is clamped by the upper clamper b and the state where the lower clamper C is released, the bonding tool d is moved together with the lower clamper C as shown in FIGS. 2(a) to 2(c). lower it,
Pellet the tip of the binding wire e that is being fed out)h
, Nono! (P), and then perform the crimping on the (h) side first. Next, Figure 2(d) ~ @Figure 2 (
As shown in g), release the clamp of the upper clamper b, raise the lower clamps C and the dending tool d, move the work stage (not shown) equipped with the eyelet h, and now -Pt-& At this position, the danding wire e is similarly crimped to the lead frame 5 while applying tension with the upper clamp 4'b, and then, as shown in Fig. 2 (h), When the bonding wire e is cut off from the crimping part of the lead frame i by clamping and lifting the lower clamper c, a pellet h is pulled through the formed wire loop j.
It is connected to the repellent lead frame i. Then, wire bonding of the semiconductor device is performed by continuously performing one cycle process like this. In addition, Fig. 2(a) shows the vertical movement during the undinda process and the second
Figure (0) Upper clamp 'Q' during the soldering process
The operating range of b is shown. However, X indicates the clamping timing of the upper cran's arm, and y indicates the clamping release timing of the upper clamp 9b.

By the way, in such a binding method, it is important for quality to always form good wire roots. For this purpose, it is necessary to apply a constant tension to the soldering wire eK, specifically approximately 1 g freely.

However, as previously mentioned, in the wire roots forming process between the binding of the top and bottom h and the bonding of the r frame i, the tension required for forming the wire roots is controlled by mechanical control of the binding. I try to use 6K wire, but it is very difficult to control the tension.1. ? There is a risk that the bonding wire e at the top of the binding tool d will sag, or there is a great possibility that the binding wire e at the bottom of the binding tool d will slack, and stable wire roots j cannot be formed. Although these problems can be solved, there is a need for a method to solve them.

[Purpose of the invention]

This invention was made in view of the above-mentioned circumstances, and its purpose is to provide a constantly stable weaving method.

[Summary of the invention]

That is, the present invention constructs the wire roots forming process by temporarily stopping the descending movement of the denting tool before binding the lead frame while applying tension to the bonding wire after the pellet is denped with the air flow. , it is possible to easily apply a constant tension to the bonding wire, and also to apply tension to the bonding wire at the bottom of the bonding tool without being affected by interference due to friction of the bonding tool by stopping the bonding tool. That is.

[Embodiments of the invention]

Hereinafter, this invention will be explained based on one embodiment showing the invention in one aspect. FIG. 3 shows an example of a wire bonding apparatus for carrying out the method of the present invention, in which 1 is a wire feeding section, 2
1. 3 has the upper cranium arm, 4 has the same lower clamp, and 5 has an ultrasonic transducer (not shown). / Deindanol. Each of these devices is attached to the bonding spatula P main body 6 in order from the upper side. Further, the wire P2, the F crank/44, and the binding tool 5 are attached via a lifting mechanism (not shown), so that they can be moved up and down in synchronization with each other. Then, the binding wire 7, which includes gold wire, aluminum wire, etc., of the wire feeding section 1 is introduced into the binding tool 5 through the wire guide 2, the upper clamp 3, and the lower clamp 4 in this order.
? 3 clamp, lower clamper 4 clamp and lifting,
Furthermore, when the bonding tool 5 is raised and lowered, /4' and l' of the let 8 mounted on a movable work stage (not shown) and between the leads of the lead frame 9 are provided.
Kf4 is provided so that the ylf landing wire 7 can be IK soldered. The wire binding device configured in this manner has the lead frame 9 glue-P'! In the middle of the descent before i-canding, the movement of the ndinguru 5 temporarily stops.

On the other hand, a tension applying mechanism 10 is provided between the wire feeding section 1 and the wire guy P2. This tension applying mechanism 10 has a tube body 1 disposed around a bonding wire 7 that is passed between a wire feed-out section 1 and a wire guy P2, and a wire feed-out section inside the tube body 10. Air is introduced toward the first side, and tension can be applied to the sanding wire 7 by the air flowing inside the tube body 10. Then, the tension applying mechanism 10 moves from the point in time when the work stage moves after finishing the bending of the bullet 8 and entering the wire loop formation start stage to the wire loop formation start stage in which the leads of the lead frame 9 are bonded. It is designed to operate within the operating range.

Further, in the operating range where this tension applying mechanism 10 works, the upper clamp 3 is set to be open, so that tension is applied to the bonding wire 7 without restraint.

In the drawings, 12 is a torch for forming a ball 13 at the tip of the winding ear 7.

Next, a method of the present invention using the wire binding device configured as described above will be explained with reference to FIGS. 4(4) to 4(C). Here, Fig. 4 (A) triyviny
"The movement (displacement) between the top and bottom of Indanol 5 is shown in 1. Figure 4 (lB) shows the bonding distance. Figure 4 shows the upper clamp with the X side clamped and the Y side open, and The opening and closing timings are shown respectively.

The bonding wire 7 is clamped with the upper clamper 3 and the lower clamp 4, and then the tip of the bonding wire 7 is touched with a torch 12. - Formed rule 13 (a)
The initial state of tmk is as follows. In this situation, first, the lower clamp/mother 4'&: is opened and the bonding tool 5 is lowered as shown in FIG. Then, at the same time as the ball 12 finishes clamping, the upper clamper 3 is released, and as the bonding tool 5 descends, the bolt 13 is tightly attached to the tip of the mending tool 5, as shown in (c). Crimp it to the pad. Through this crimping and ultrasonic imaging, the bonding on the pellet 8 side is performed. Then, after the binding on the pellet 8 side is completed, the bonding tool 5 is released while the upper clamp holder 3 and the lower clamp 94 remain open. It rises as shown in (d), and then the work stage (not shown) moves a required distance in the direction of stretching the loop as shown in (e) K, and attaches the lead frame 9 to the tip of the binding tool 5!j-1''
f: Guide. Then, the tension applying mechanism 10 is activated from the start of movement of the work stage, which is the start stage of wire loop formation, and a constant tension is applied to the binding wire 7 by the air flow K. In addition to this, each clan has 3
．． The slack of the binding wire 7 between the binding wires 7 and 4, that is, the upper side of the binding tool 5 can be taken up. Then, at the same time as the movement of the work stage is completed, the bonding tool 5 is lowered as shown in (f) with the upper clamp 3 and lower clamp 4 remaining open, and then lowered as shown in (g). The 7'' binding wire 7 is crimped to the lead of the lead 9 frame 9, and binding is performed in the same manner as on the pellet 8 side described above. However, although wire bonding is performed between the bellet 8 and the lead frame 9 by forming two wire loops, if the wire bonding is performed as it is, the length of the wire loop below the bonding tool 5 will change due to slack.However, in the method of this invention, During the lowering operation of the binding tool 5 before sanding the lead frame 9, which is the wire loop forming process, the movement of the binding tool 5 is stopped in area E. Therefore, tension due to the air flow is applied to the binding wire 7 below the bonding tool 5, which is caused by all the friction with the bonding tool 5, and the slack is removed to form a wire loop L having the required length. can do. Therefore, it is possible to eliminate angles and the like that occur due to slack, and it is possible to always form a stable and good wire loop L.

-4. After finishing the gendering of the lead frame 9, clamp the lower clamp and 4, raise the binding tool 5 as shown in h), and pull the colored conding wire yt- on the crimped part of the lead frame 9. Cut, torch 1
At step 2, a ball 13 is formed at the tip of the binding wire 7 protruding from the tip of the bonding tool 5 using a torch 12, and the upper clamp 3 is clamped to complete one cycle of the wire bonding process. and,
This wire binding step is performed successively in correspondence with the number of pads of the bullet 8 and the number of wires P in the frame 9 that are in connection with the pads of the bullet 8 and their holes and rads.

In the above method, the upper clamper is used to hold the wire binding, but the tension generated by the air flow may be used instead. Details i
'j1. ! (,i, >) in Figure 4 (B).

It will serve as the upper clamp/mother clamp in each stage of (1).

〔Effect of the invention〕

As explained above, according to the present invention, in addition to easily applying a constant tension to the bonding wire, the bonding wire (D It is possible to provide a wire bonding method that can eliminate wire loops and always form stable wire loops, which greatly contributes to improving the yield of products. It's large.

[Brief explanation of the drawing]

Figure 1 shows wire 1 using the conventional wire winding method. Fig. 2 (4) is a block diagram showing the binding device;
Bl is a process diagram for explaining the bonding method, and Fig. 2 (Q is a diagram showing the opening and closing timing of the upper clamper, @Figs. 3 and 4 (A), (B), 'f).
c) shows an embodiment according to the present invention, Fig. 3 is a configuration diagram showing a wire binding device to which the method of this invention is applied, and Fig. 4) shows bonding as the bonding progresses in the wire binding device. Figure 4' (B), which is a line diagram showing the elevation change of the tool, is a process diagram 1. for explaining the binding method. ! 4 (C) is a diagram also showing the opening and closing timing of the upper clamper. DESCRIPTION OF SYMBOLS 1... Wire feeding part, 5... Bonding tool, 7... Bonding wire, 8... Beret,
9...Lead frame, 1o...Tensioning structure/Patent attorney Suzue Takehiko Figure 1 (A Figure 2)

Claims (1)

[Claims] The binding wire in the wire feeding section is led to a bonding tool, the leading end of the binding wire is bonded to the pellet of the semiconductor device by raising and lowering the T-tending tool, and then the semiconductor device is moved. In the df bonding method, the wire loop is bonded to the lead frame of a semiconductor device by raising and lowering the binding tool again while forming a wire loop. A method for winding a wire, which is characterized in that the lowering movement of the binding tool is temporarily stopped before the wire is wired to the lead frame 1 while applying tension.