JPH0878463A - Wire bonder and bonding method - Google Patents

Abstract

PURPOSE: To suppress defective bonding caused by an initial ball having defective profile. CONSTITUTION: The wire bonder comprises a capillary 4 through which a wire is passed, a torch 5 for making a discharge loop with respect to the forward end of the wire 6 passed through the capillary 4 and forming an initial ball 6a thereat, and an image recognition unit 16 serving as a unit for measuring the size of the initial ball 6a.

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 and method for connecting a semiconductor and an electrode provided on a substrate, a lead frame or the like with a conductive wire.

[0002]

2. Description of the Related Art A conventional wire bonding apparatus and method will be described below with reference to FIGS. Figure 5
In FIG. 1, 1 is a heat block, 2 is a heater, 3 is a substrate, 4 is a capillary, 5 is a torch (discharging electrode) arranged in the vicinity of the capillary 4, 6 is gold, aluminum or the like which is inserted into the capillary 4. Become wires,
Reference numeral 7 is a clamper for the wire 6, 8 is an ultrasonic horn, and both the clamper 7 and the ultrasonic horn 8 are attached to a holder 9, and the holder 9 is pivotally supported by a bracket 11 by a rotating shaft 10. The capillary 4 is configured so as to be swingable in the up and down direction. 12 is a linear motor device for swinging the holder 9, 13
Is an X for moving the bracket 11 in the XY direction.
-Y table.

Next, a bonding method using the above wire bonding apparatus will be described with reference to FIGS. 6 and 7. FIG. 6 shows a case in which the electrode portion 14a of the IC component 14 arranged on the substrate and the substrate electrode 15 are connected by the wire 6. First, the bonding of the substrate 3 mounted on the heat block 1 is performed. Heating the area, ultrasonic horn 8
Ultrasonic waves are applied to the above to make the above connection, and FIG. 7 shows the details of the process. In this step, first, a first bonding step of bonding one end of the wire 6 to the electrode portion 14a of the IC component 14 and another portion of the wire 6 on the substrate electrode 15 are performed.
A second bonding step of bonding to the
After the bonding step, a step of discharging an electric ball to the tip of the wire cut by pulling up the clamper 7 and the tip of the wire from the torch 5 forming a discharge loop to form an initial ball is repeated. Of.

[0004]

However, when bonding is performed in this way, the problem is the step of forming the initial balls, and the variation in the size of the initial balls formed in this step is as follows. It affects the bonding process. That is, if the diameter of this initial ball is too small, it is highly likely that this will cause defective wire bonding in the next bonding step.
This has been one of the causes of deteriorating the yield of IC substrate production.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wire bonding apparatus and method for reducing the number of defective bonding due to the defective initial ball shape.

[0006]

In order to achieve the above object, the present invention forms a capillary having a wire inserted therein, a tip of the wire inserted in the capillary and a discharge loop, and forms an initial ball therein. A torch and a measuring device for measuring the size and the like of the initial ball are provided.

[0007]

Therefore, according to the present invention, it is possible to reduce defective bonding and realize high quality bonding by prior recognition of defective initial balls.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. The same parts as those of the conventional wire bonding apparatus are designated by the same reference numerals. FIG. 1 is a perspective view showing the vicinity of a capillary of a wire bonding apparatus in a first embodiment of the present invention. In the figure, 4 is a capillary, 5 is a torch (discharge electrode) arranged near the capillary 4, and 6 is a torch. A wire made of gold, aluminum or the like that is inserted into the capillary 4, 7 is a clamper for the wire 6, 8 is an ultrasonic horn, and the clamper 7
The ultrasonic horn 8 and the ultrasonic horn 8 are both attached to a holder 9, and the holder 9 is pivotally supported by a bracket 11 by a rotating shaft 10 so that the capillary 4 can be vertically swung about this. . An image recognition device 16 serves as a measuring device, and includes a camera device 16a for picking up an image of the initial ball 6a formed on the wire 6 near the tip of the capillary 4 and a recognition data processing device 16b. Note that FIG.
The heat block 1, the heater 2, the substrate 3, the linear motor device 12, the XY table 13 and the like in the conventional apparatus shown in FIG. 3 are similar in this embodiment, but they are omitted in the drawing.

The bonding method using the above apparatus is almost the same as that shown in FIGS. 6 and 7, but as shown in FIG. 3, the image recognition apparatus 16 to be a measuring device after the initial ball forming step 16 The difference is that the step of measuring the initial ball size is added, and in this embodiment, the size, shape, position, etc. of the initial ball 6a are recognized and converted into data by the data processing of the recognition data processing device 16b. However, even if only the size of the initial ball 6a is measured, a corresponding effect can be expected.

In this way, the quality of the initial ball 6a can be known in advance, and it becomes possible to judge and respond whether or not to proceed to the next bonding step as it is. The diameter of this initial ball 6a is 60 to 70 μm.
Since the image resolution is small, the resolution of the image is submicron, and the subpixel method is used as the data processing method (the decomposition of 1 pixel or less is compensated by the image processing technology).

FIG. 2 is a perspective view showing the vicinity of a capillary of a wire bonding apparatus according to a second embodiment of the present invention. In the figure, the same parts as those of the conventional device and the same parts as those of the first embodiment are the same. Shall be attached. The present embodiment is different from the first embodiment except that a laser type ball size reading device 17 serving as a measuring device is used in place of the image recognition device 16 used in the initial ball size measurement step. Same as the embodiment. This laser type ball size reading device 17 also has a built-in data processing device. Therefore, the size, shape, position, etc. of the initial ball 6a are recognized and converted into data by the same data processing as in the first embodiment. The quality of 6a can be judged in advance.

In this way, it is possible to judge the quality of the initial ball 6a, which makes it easier to take countermeasures.
If this is defective, it is necessary to temporarily stop the equipment at that point in order to prevent the process from proceeding to the next bonding step as it is.

The bonding method shown in the flow chart of FIG. 4 is intended to improve this point. After the step of measuring the initial ball size in the flow chart shown in FIG. 5 is again instructed to spark the wire 6, the initial ball 6a is formed again, the number of times of this instruction is counted, and a process of continuing this until the prescribed number is reached is added. . In addition,
In response to this spark command, if the voltage, current, time, etc. applied to the torch 5 are made larger than in the first time, then good initial ball formation can be performed faster.

In each of the above embodiments, the wire bonding in the substrate has been described, but it goes without saying that it is also applicable to wire bonding of a general lead frame specification.

[0015]

As described above, the present invention can provide a bonding apparatus and method capable of reducing defective bonding due to defective initial balls and realizing high quality bonding.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a main part of a bonding apparatus in a first embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a main part of a bonding apparatus according to a second embodiment of the present invention.

FIG. 3 is a flowchart for explaining a first bonding method by the bonding apparatus of the present invention.

FIG. 4 is a flow chart for explaining a second bonding method by the bonding apparatus of the present invention.

FIG. 5 is a schematic perspective view showing a main part of a conventional bonding apparatus.

FIG. 6 is a schematic perspective view for explaining a bonding method using a conventional bonding device.

FIG. 7 is a flowchart for explaining a bonding method using a conventional bonding apparatus.

[Explanation of symbols]

1 ... Heat block, 2 ... Heater, 3 ... Substrate, 4
… Capillaries, 5… Torches, 6… Wires, 7…
Clamper, 8 ... Ultrasonic horn, 9 ... Holder, 10
... Rotation axis, 11 ... Bracket, 12 ... Linear motor device, 13 ... XY table, 14 ... IC parts, 15 ... Board electrode, 16 ... Image recognition device, 17 ... Laser ball size reading device.

Continued Front Page (72) Inventor Satoshi Soda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (6)

[Claims] 1. A capillary into which a wire is inserted, a torch that forms a discharge loop with the tip of the wire inserted into the capillary and forms an initial ball therein, and a measuring device that measures the size of the initial ball. A wire bonding device characterized by being provided. 2. The wire bonding apparatus according to claim 1, wherein an image recognition device is used as the measuring device. 3. The wire bonding apparatus according to claim 1, wherein a laser ball size reading device is used as the measuring device. 4. A step of bonding the wire to a first bonding point by a capillary having a wire inserted therein, and a step of bonding the wire to a second bonding point to be connected to the first bonding point through the operation of the capillary. And a step of forming an initial ball on the tip of the wire cut at the second bonding point, and a step of measuring the size of the initial ball. 5. The wire bonding method according to claim 4, further comprising a step of feeding back a wire determined to be defective in the step of measuring the size of the initial ball to the step of forming the initial ball. 6. The wire bonding method according to claim 5, further comprising means for stopping the feedback step when the feedback in the feedback step has been determined to be defective even after reaching a prescribed number of times. .