JP3324397B2 - Wire bonding equipment - Google Patents

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 for connecting a substrate and a chip with wires.

[0002]

2. Description of the Related Art A conventional wire bonding apparatus for connecting electrodes of a substrate, such as a lead frame or a printed circuit board, with electrodes of a chip mounted on the substrate by wires.
This will be described below.

FIG. 5 is a side view of a conventional wire bonding apparatus, and FIG. 6 is a plan view of the same. Reference numeral 1 denotes a main body, and a horn 2 extends forward from the main body 1. Main unit 1
Is mounted on the movable table 3 and moves horizontally in the X and Y directions when the movable table 3 is driven.
A drive unit such as a cam 4, a cam follower 5, and a motor (not shown) for swinging the horn 2 up and down around the pin 11 is built in the main body 1. Further, a vibrator 6 for applying ultrasonic vibration to the horn 2 is mounted on the base end side of the horn 2.

[0004] A bracket 7 is provided on the main body 1. The bracket 7 holds a spool 9 around which a wire 8 is wound. A motor M for rotating the spool 9 and leading out the wire 8 is mounted on the rear surface of the bracket 7. Wire 8 derived from spool 9
Is the capillary tool 1 held at the tip of the horn 2
0 is inserted. Reference numeral 17 denotes a guide for guiding the wire 8 to be led out, and reference numeral 18 denotes an air tensioner for applying an appropriate tension to the wire 8. In FIG. 6, the air tensioner 18 is omitted.

[0005] An arm 13 extends from the upper portion of the main body 1 in the same direction as the horn 2, and a lens barrel 14 is held upright at the tip of the arm 13. A camera 15 is mounted on the upper part of the lens barrel 14. Reference numeral 16 denotes a heat block as a substrate heating means, on which a substrate 19 is mounted. The chip C is mounted on the substrate 19. The camera 15 recognizes the positions of the electrodes of the substrate 19 and the chip C. The heater 16 heats the substrate 19 and the chip C to facilitate bonding of the wire 8. Reference numeral 12 denotes a torch, which is located at a position close to the lower end of the wire 8 led downward from the capillary tool 10, and is provided with a ball 8 'on the lower end of the wire 8 by an electric spark generated by applying a high voltage. To form It should be noted that a clamper for clamping the wire 8 and a means for transporting the substrate 19 are omitted.

[0006] This conventional wire bonding apparatus has the above-described configuration, and its operation will be described below. Chip C
When the substrate 19 on which is mounted is transported onto the heat block 16, the movable table 3 is driven to move the lens barrel 14 above the chip C, and the substrate 19 and the electrodes of the chip C are observed by the camera 15. , Perform its position recognition. Next, based on this position recognition, the movable table 3 is driven to horizontally move the capillary tool 10 in the X and Y directions, and the horn 2 is swung up and down while being drawn out from the lower end of the capillary tool 10. The chip C and the electrodes of the substrate 19 are successively connected by the wire 8.

[0007]

In order to ensure the bonding property of the wire 8, a wire bonding apparatus is required.
Heating means for the substrate 19 such as the heat block 16 is provided. Since the heating means radiates heat upward, the horn 2 is gradually warmed and thermally expanded. As a result, there is a problem that the position of the capillary tool 10 is deviated and the bonding position is deviated.

[0008] Similarly, the air in the optical path to the camera 15 for capturing an image above the substrate 19 is also warmed, and as a result, the optical path is liable to generate fogging. If the optical path is blurred, a clear image cannot be obtained by the camera 15, an error occurs in the recognition of the position of the substrate 19 or the chip C, and the positional accuracy of bonding is reduced.

Further, the wire bonding apparatus must be operated at a high speed in order to increase productivity. Therefore, the movable table 3 must be driven at a high speed to move the capillary tool 10 horizontally at a high speed in the X and Y directions. Further, every time a new chip C is sent to the bonding operation position, the camera 15 must be moved above the chip C to perform a predetermined recognition.

As described above, the wire bonding apparatus is required to operate at a high speed. However, since the heavy arm 13 is cantilevered by the main body 1 and extends forward, vibration is likely to occur with high-speed movement.
When the arm 13 provided with the optical system for capturing an image vibrates in this manner, a clear image cannot be obtained.
The capture of an image must wait until the vibration stops, which has been a bottleneck for speeding up the wire bonding apparatus. In order to solve such problems,
It is conceivable that the arm 13 is strengthened to suppress vibration. However, if the arm 13 is strengthened, the weight increases, and the load of high-speed movement by driving the movable table 3 increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wire bonding apparatus which solves the above-mentioned problems, prevents the occurrence of a flash when capturing an image, and suppresses the occurrence of vibration of an arm during high-speed movement. .

[0012]

A wire bonding apparatus according to the present invention is provided with a main body, a movable table for moving the main body in a horizontal direction, a horn extending from the main body, and a main body. A driving unit that causes the horn to move up and down, a capillary tool held at the tip of the horn and through which a wire is inserted, an arm extending from the main body, and a substrate mounted on the tip of the arm. An image capturing unit for capturing an image of a chip or a chip, a torch extending below the capillary tool, heating means for heating a substrate below the capillary tool, and a device extending along the longitudinal direction of the horn. A first air blower that blows air to the horn and a lower end thereof is connected to the first air blower, and the other end supports a tip end side of the arm to form the image. It is obtained by a second air blowing section which blows air toward the vertical optical path of the write portion.

[0013]

According to the present invention, the horn is cooled by blowing air toward the horn from the first air blowing portion to eliminate the thermal expansion thereof, and the horn is cooled by the second air blowing portion. By blowing out air, the occurrence of shading on the optical path for image capture is eliminated.

The distal end of the arm extending in a cantilevered state from the main body is supported by the second air blowing section, so that vibration of the arm during high-speed movement is suppressed, and a clear image can be formed at high speed. Can be obtained.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a wire bonding apparatus according to an embodiment of the present invention, FIG. 2 is a plan view of the same, FIG. 3 is a cross-sectional view of the image capturing unit, and FIG. is there. In FIG. 1, reference numeral 20 denotes a movable table,
The main body 21 is provided on the upper surface. When the movable table 20 is driven, the main body 21 is moved in the X direction and Y direction.
Move horizontally in the direction. Horn 22 forward from body 21
Is extending. A driving unit 28 for swinging the horn 22 in the up-down direction and a horn 22
A vibrator (not shown) for applying an ultrasonic vibration to the device is built in.

A bracket 2 is provided on one side of the main body 21.
3 are installed. On a front surface of the bracket 23, a spool 25 around which a wire 24 is wound is rotatably held. A motor M for rotating the spool 25 and leading out the wire 24 is mounted on the rear surface of the bracket 23 (FIG. 2). 26 is a guide for guiding the wire 24 attached to the bracket 23. As shown in FIG. 2, the bracket 23 is inclined with respect to the extension direction A of the horn 22, and therefore, the leading direction B of the wire 24 is at an angle θ in a plan view with respect to the extension direction A of the horn 22. Crosses obliquely. The wire 24 led out from the spool 25 is inserted through a capillary tool 27 held at the tip of the horn 22.

In FIG. 1, the arm 3 is
0 extends in the same direction as the horn 22. An elongated lens barrel 31 is provided on the arm 30. The camera 32 is installed on the main body 21 and connected to one end of the lens barrel 31. An image capturing section 33 is connected to the distal end of the lens barrel 31. As shown in FIG. 3, a mirror 35 is obliquely provided inside the image capturing unit 33. As described above, the distance d (FIG. 2) between the capillary tool 27 and the image capturing unit 33 can be shortened by making the drawing direction B of the wire 24 intersect with the extending direction A of the horn 22.

In FIGS. 1 and 4, reference numeral 41 denotes a first air outlet, and reference numeral 42 denotes a second air outlet. The first air blowing portion 41 is a cylindrical body in which air blowing holes 43 are formed at a pitch, and one end of the first air blowing portion 41 is attached to the arm 3 by a fitting 44.
0 is held at the lower end. The first air blowing section 41 is disposed parallel to the horn 22 so as to be along the horn 22. The second air outlet 42 is also a cylinder having an air outlet 45. The second air blowing unit 42 is provided for the image capturing unit 3.
3 is arranged upright along a vertical optical path K for capturing an image, and its upper end is supported by the lower surface of the tip of the arm 30 (see also FIG. 3). The distal end of the first air outlet 41 and the lower end of the second air outlet 42 are connected by a block 46.

In FIG. 4, a pipe 70 is
Is connected, and air is pressure-fed from an air supply unit (not shown) to the first air blowing unit 41 through the pipe 70. The upper end of the second air outlet 42 is connected to the lower surface of the distal end of the arm 30 by a fixture 71. Fixture 71
A pipe 72 is connected to the air supply unit, and air is pressure-fed from the air supply unit to the second air blowing unit 42 through the pipe 72. Reference numeral 73 denotes a screw for fixing the attachment 71 to the lower surface of the arm 30.

Below the tip of the horn 22, a heat block 50 is provided as a means for heating the substrate. The substrate 51 is placed on the heat block 50. A chip 52 is mounted on a substrate 51. The substrate 51 and the chip 52 are heated by the heat block 50,
The horn 22 is also heated by the heat radiation. When the horn 22 thermally expands due to this heating, the position of the capillary tool 27 is deviated, and the positional accuracy of the wire bonding is reduced. Therefore, air is blown out from the first air blowing portion 41 toward substantially the entire length of the horn 22 to cool the horn 22 and suppress its thermal expansion.

Further, due to the heat radiation of the heat block 50, the air between the heat block 50 and the image capturing section 33 is warmed, so that the optical path K for image capturing by the image capturing section 33 is fogged. When the blurring occurs, the image obtained by the camera 32 is distorted, and the image accuracy is reduced. Therefore, the second air blowing section 42 blows out air to prevent a rise in the temperature of the air in the optical path K for taking in the image, eliminate the occurrence of flash, and obtain a clear image.

In FIG. 1, reference numeral 60 denotes a support unit which holds a rod-shaped torch 54. The tip of the torch 54 is close to the lower end of the wire 24 that is led downward from the lower end of the capillary tool 27. Torch 54
When a high voltage is applied to the tip of the torch 54 and the wire 2
4 between the lower ends of the wires 4
A ball is formed at the lower end of the. 55 is a stopper attached to the side of the distal end of the arm 30, and 56 is an air tensioner held at the distal end of the stopper 55. The wire 24 led out of the spool 25 passes through the inside of the air tensioner 56 and is sent to the capillary tool 27.

This wire bonding apparatus is configured as described above, and the operation will be described next. In FIG. 1, when the substrate 51 is sent to below the tip of the horn 22 by a transport unit (not shown), the movable table 20 is driven to move the image capturing unit 33 above the chip 52,
An image near the chip 52 is obtained by the camera 32. A computer (not shown) analyzes this image and recognizes the positions of the electrodes of the substrate 51 and the chip 52.

Next, the capillary tool 27 is moved above the chip 52, the movable table 20 is driven to move the capillary tool 27 in the X direction and the Y direction, and the drive unit 28 is driven to move the horn 22 in the vertical direction. The electrode of the chip 52 and the electrode of the substrate 51 are connected with the wire 24 while swinging. Note that such a wire bonding operation is a known operation.

During the wire bonding operation, the wire 2
The substrate 51 is heated by the heat block 50 to secure the bonding property of No. 4. When the horn 22 thermally expands due to the heat radiation of the heat block 50, the position of the capillary tool 27 is deviated, and the positional accuracy of the bonding is also reduced. Then, the horn 22 is cooled by blowing air from the air outlet 43 of the first air outlet 41. In addition, when the image capturing unit 33 captures an image of the substrate 51 or the chip 52 as described above, if heat radiation occurs in the heat block 50, a clear image cannot be obtained. Therefore, when the image is taken in by the image taking section 33, the cold air is blown out from the blowout hole 45 of the second air blowout section 42 to prevent the occurrence of the fogging.

The capture of the image of the substrate 51 and the chip 52 is as follows.
This is performed every time a new tip 52 is sent below the tip of the horn 22. Therefore, every time a new chip 52 is sent below the tip of the horn 22, the movable table 20 must be driven to move the image capturing section 33 above the chip 52, as shown in FIG. In addition, since the lead-out direction B of the wire 24 is inclined with respect to the longitudinal direction A of the horn 22, the distance d between the image capturing unit 33 and the capillary tool 27 is reduced, so that the camera 32
And the switching of the wire bonding operation by the capillary tool 27 can be performed in a short time, and the productivity can be increased accordingly.

The heavy camera 32 is supported on the main body 21, and the arm 30 only supports the lightweight lens barrel 31 and the image capturing section 33.
Weight load is small. In addition, the free end of the arm 30 is supported at the upper end of a second air outlet 42 connected to the first air outlet 41. Therefore, even if the arm 30 is moved at a high speed in the X direction or the Y direction, the vibration of the arm 30 is small, and a desired image can be obtained while being stably moved at a high speed. Note that image capture is performed at a plurality of locations for one chip 52.

The present invention is not limited to the above embodiment, and various design changes are possible. For example, in the above-described embodiment, the first air blowing section 41 and the second air blowing section 42 are separate bodies, and both are connected by the block 46. However, the first air blowing section and the second air blowing section are connected. The horn may be cooled by the first air outlet,
It is sufficient to prevent the occurrence of a fogging at the air blowing portion, and to firmly support the tip end side of the arm to prevent the vibration of the arm. Further, a camera may be attached to the tip of the arm as shown in the conventional example, and the camera may be used as an image capturing unit to obtain an image. However, in this case, since the camera is heavy, vibration is likely to occur during high-speed movement. Therefore, as in the above embodiment,
It is desirable to provide a light optical system as light as possible.

[0029]

According to the present invention, since the horn can be cooled by blowing air from the first air blowing portion toward the horn and its thermal expansion can be eliminated, the position of the capillary tool can be eliminated. , High bonding position accuracy can be secured. In addition, by blowing air from the second air blowing unit, it is possible to eliminate the occurrence of a fogging in the optical path for capturing images, obtain a clear image with a camera, and secure high bonding position accuracy.

The distal end of the arm extending in a cantilevered state from the main body is supported by the second air blowing section, so that vibration of the arm during high-speed movement is suppressed, and a clear image can be formed at high speed. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a wire bonding apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of a wire bonding apparatus according to an embodiment of the present invention.

FIG. 3 is a sectional view of an image capturing unit of the wire bonding apparatus according to the embodiment of the present invention;

FIG. 4 is a perspective view of the vicinity of a tip of a horn of the wire bonding apparatus according to the embodiment of the present invention;

FIG. 5 is a side view of a conventional wire bonding apparatus.

FIG. 6 is a plan view of a conventional wire bonding apparatus.

[Explanation of symbols]

 Reference Signs List 20 movable table 21 main unit 22 horn 24 wire 25 spool 27 capillary tool 28 driving unit 30 arm 31 lens barrel 32 camera 33 image capturing unit 50 heat block 51 substrate 52 chip

Claims (1)

(57) [Claims] A main body, a movable table for moving the main body in a horizontal direction, a horn extending from the main body, a driving unit provided in the main body for causing the horn to perform up and down operations; A capillary tool which is held at the tip of the horn and through which a wire is inserted, an arm extending from the main body, and an image capture unit mounted on the tip of the arm for capturing an image of a substrate or chip A torch extending below the capillary tool, a heating means below the capillary tool for heating the substrate, and an air blown to the horn disposed along the longitudinal direction of the horn. A first air outlet and a lower end are connected to the first air outlet, and the other end supports the distal end of the arm and directs air toward a vertical optical path of the image capturing unit. The second air blowing Wire bonding apparatus being characterized in that a by unit.