JP3314617B2 - 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 to electrodes of a chip mounted on the substrate by wires is described below.
This will be described below.

FIG. 7 is a side view of a conventional wire bonding apparatus, and FIG. 8 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. 8, 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. Then, based on the position recognition result, the movable table 3 is driven to horizontally move the capillary tool 10 in the X direction or the Y direction, and the horn 2 is oscillated in the vertical direction 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]

As described above, the torch 12 is located at a position close to the lower end of the wire 8 extending downward from the capillary tool 10, and a high voltage is applied to the torch 12 to apply a high voltage thereto. An electric spark is generated between the distal end and the lower end of the wire 8, thereby forming a ball 8 ′ at the lower end of the wire 8. Then, the ball formed by lowering the capillary tool 10 is moved to the capillary tool 10. The lower end is pressed against the electrode on the upper surface of the chip C for bonding.

A ball 8 'formed at the lower end of the wire 8
Depends on the diameter of the wire 8, the magnitude of the applied voltage, the voltage application time, the positional relationship between the tip of the torch 12 and the lower end of the wire 8, and the like. Therefore, in order to form a ball 8 'of a desired size, the torch 1
It is desirable to be able to easily and precisely adjust the positional relationship between the tip 2 and the lower end of the wire 8.

Accordingly, the present invention provides a wire bonding apparatus provided with an adjusting means capable of simply and precisely adjusting the positional relationship between the tip of the torch and the lower end of the wire in order to form a ball of a desired size. Aim.

[0010]

According to the present invention, there is provided a horn, a capillary tool which is held at the tip of the horn and through which a wire is inserted, a driving unit which causes the horn to perform up and down operations, and A torch extending downward from the capillary tool, and a holding unit for holding the torch, the holding unit being mounted on a first block mounted on a vertical rotating shaft, and being mounted on the first block so as to be able to move forward and backward. A second block, and a third block mounted on the second block so as to be vertically movable and holding the torch, and the first block is horizontally rotated about the rotation axis to thereby provide a torch tip. The position of the tip of the torch in the Y direction is adjusted by moving the second block forward and backward with respect to the capillary tool, and And to adjust the position in the Z direction of the torch head by vertically moving serial third block.

[0011]

According to the present invention, the position of the tip of the torch in the X, Y, and Z directions with respect to the lower end of the wire can be easily and precisely adjusted. A ball having a size of

Next, an embodiment of the present invention will be described with reference to the drawings. 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. 4 is a perspective view of the holding unit and a horn. 5 is a sectional view of the holding unit, and FIG. 6 is a sectional view of the holding unit.

In FIG. 1, reference numeral 20 denotes a movable table, on which a main body 21 is provided. When the movable table 20 is driven, the main body 21 horizontally moves in the X direction and the Y direction. A horn 22 extends forward from the main body 21. The horn 2 is provided inside the main body 21.
A drive unit 28 for swinging the horn 2 vertically and a vibrator (not shown) for applying ultrasonic vibration to the horn 22
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, since the lead-out direction B of the wire 24 intersects the lead-out direction A of the horn 22, the distance d (FIG. 2) between the capillary tool 27 and the image capturing unit 33 can be reduced.

In FIG. 1, reference numeral 41 denotes a first air blowing portion;
Reference numeral 42 denotes a second air blowing unit. First air blowing section 41
Is a cylindrical body in which air blowing holes 43 are formed at a pitch, and one end of the cylindrical body is held at a lower end of the arm 30 by a fixture 44. The first air outlet 41 is provided by the horn 22
Are arranged in parallel with the horn 22 so as to follow. The second air outlet 42 is also a cylinder having an air outlet 45. The second air blowing unit 42 is arranged upright along the vertical optical path K for image capturing by the image capturing unit 33, and the upper end is supported by the lower surface of the distal end of the arm 30 ( See also FIG. 3). Also, the first air blowing section 41
And the lower end of the second air blowing section 42
6 are connected.

A heat block 50 as a means for heating the substrate is provided below the tip of the horn 22. 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, and 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, the heat between the heat block 50 and the image capturing section 33 is warmed by the heat radiation of the heat block 50, so that the optical path K of the 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, by blowing out air from the second air blowing section 42, the temperature of the air in the optical path K for taking in the image is prevented from rising, and the occurrence of flash is eliminated to obtain a clear image. A description of a piping system for supplying air to the first air blowing unit 41 and the second air blowing unit 42 will be omitted.

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.

Next, the structure of the holding unit 60 will be described with reference to FIGS. The holding unit 60 includes a first block 61, a second block 62, and a third block 63. The torch 54 is held by inserting its base end into the third block 63. Reference numeral 64 denotes a support member supported on the arm 30 side, and a vertical rotation shaft 65 is mounted on a divided distal end portion. The first block 61 is mounted on the rotating shaft 65 and horizontally rotates around the rotating shaft 65 in the direction of arrow A. By this rotation, the position of the tip of the torch 54 in the X direction with respect to the lower end of the wire 24 derived from the lower end of the capillary tool 27 can be adjusted.
In the present invention, a longitudinal direction of the horn 22 is defined as an X direction, a direction orthogonal thereto is defined as a Y direction, and a vertical direction is defined as a Z direction.

As shown in FIG. 5, a horizontal guide rod 66 is inserted into the first block 61. Reference numeral 67 denotes the bearing bearing. The second block 62 is mounted on the distal end of the guide rod 66. Guide rod 6
6, a horizontal screw rod 68 is inserted. The tip of the screw rod 68 is inserted into the second block 62.
The rear end of the screw rod 68 protrudes from the back of the first block 61, and a nut 69 is screwed to this protruding portion. A spring 70 is interposed between the first block 61 and the second block 62.

The spring 70 is resilient in the direction of separating the first block 61 and the second block 62 from each other in FIG. Therefore, if the nut 69 is screwed in, the distance between the first block 61 and the second block 62 is reduced, and if the nut 69 is loosened, the distance is increased, whereby the second block 62 is led out from the lower end of the capillary tool 27. The wire 24 is advanced and retracted in the Y direction with respect to the lower end of the wire 24 to adjust the position of the torch 54 in the Y direction.

In FIG. 6, a long slot 71 is formed in the second block 62 so as to extend vertically. This long 71
The nut 72 is screwed to the tip of the bolt 72 protruding from the third block 63. Therefore, the position of the tip of the torch 54 in the Z direction (height direction) is adjusted by loosening the bolt 72 and the nut 73 and moving the third block 63 up and down with respect to the second block 62. A lead wire 74 is connected to the base end of the torch 54.
When a high voltage is applied to the wire 24, an electric spark is generated between the lower end of the wire 24 derived from the lower end of the capillary tool 27 and the tip of the torch 54, and a ball 24 'is formed at the lower end of the wire 24. .

Since the holding unit 60 is configured as described above, the X of the tip of the torch 54 with respect to the lower end of the wire 24 extending from the lower end of the capillary tool 27
Direction, Y direction, Z direction position easily and accurately,
A ball 24 'having a desired size can be formed at the lower end of the wire 24.

This wire bonding apparatus has the above configuration, 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 torch 52, the movable table 20 is driven to move the capillary tool 27 in the X direction and the Y direction, and the driving 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
In order to secure the bonding property of No. 4, the substrate 51 is heated by the heat block 50. This heat block 50
When the horn 22 thermally expands due to the heat radiation, the position of the capillary tool 27 is disturbed, and the positional accuracy of the bonding is also reduced. Therefore, the horn 2 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.

[0030]

According to the present invention, the position of the tip of the torch in the X, Y, and Z directions with respect to the lower end of the wire can be easily and accurately adjusted, so that a desired size can be obtained by applying a voltage to the torch. Ball can be formed.

[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 a holding unit and a horn of the wire bonding apparatus according to one embodiment of the present invention.

FIG. 5 is a sectional view of a holding unit of the wire bonding apparatus according to one embodiment of the present invention;

FIG. 6 is a sectional view of a holding unit of the wire bonding apparatus according to one embodiment of the present invention;

FIG. 7 is a side view of a conventional wire bonding apparatus.

FIG. 8 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

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/60

Claims (1)

(57) [Claims] 1. A horn, a capillary tool at a tip of the horn, into which a wire is inserted, a driving unit for causing the horn to move up and down, and a tip extending below the capillary tool. A torch, and a holding unit for holding the torch. The holding unit includes a first block mounted on a vertical rotating shaft, a second block mounted on the first block so as to be able to move forward and backward, A third block which is attached to the second block so as to be vertically movable and holds the torch, and adjusts the position of the tip of the torch in the X direction by horizontally rotating the first block about the rotation axis. The position of the tip of the torch in the Y direction is adjusted by moving the second block forward and backward with respect to the capillary tool, and the third block is moved up and down. Wire bonding apparatus and performs position adjustment in the Z direction of the torch head by Rukoto.