JP2000150545A - Die bonder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die bonder which can bond a chip to the island of a lead frame with positional accuracy by accurately observing the island with a camera. SOLUTION: A light transmitting and diffusing body 8a is installed to part of a backup plate 8A which supports a lead frame 12 from the downside at the bonding position of a chip and the island 12a of the lead frame 12 is supported by the body 8a. When light is emitted from a cable 41 housing an optical fiber, the light is made incident to the body 8a from one side face and uniformly diffused. Therefore, the chip can be bonded to the island 12a with positional accuracy by accurately finding the bonding position of the chip by clearly observing the silhouette of the island 12a in a bright background by means of a camera 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a die bonding apparatus for bonding a chip to a lead frame.

[0002]

2. Description of the Related Art As a method of mounting a chip on a lead frame, there is known a method of bonding a chip by using a chip bonding paste. In a die bonding apparatus for bonding chips, a lead frame is transported on a transport rail, paste is applied to the island of the lead frame on the transport rail, and then the chip is bonded on the island.

[0003]

Prior to bonding a chip to an island of a lead frame, a camera is used to observe the island in order to recognize the bonding position of the chip. However, since the lead frame is formed by punching a thin metal plate by press working or the like, the shoulder of the island is sagged, which makes it difficult to accurately image the planar shape of the island with a camera. Therefore, there is a problem that the bonding position of the chip obtained from the imaging result is likely to be out of order, and the bonding position accuracy of the chip is not improved.

Accordingly, an object of the present invention is to provide a die bonding apparatus capable of accurately observing an island of a lead frame with a camera and bonding a chip with high positional accuracy.

[0005]

SUMMARY OF THE INVENTION A die bonding apparatus according to the present invention includes a bonding means for bonding a chip to a lead frame, a camera for observing the lead frame at a bonding position from above, and a chip supply for supplying the chip to the bonding means. And a transfer means for transferring the lead frame to the bonding means, two parallel transfer rails for transferring the lead frame, and a transfer means between the transfer rails for chip bonding. A backup plate for supporting the lead frame from below; a light source for transmitting light and diffusing the light, wherein a part or all of the backup plate is made of a light transmission diffuser for transmitting and diffusing light; Means were provided.

In the above arrangement, if light is incident from the light source means into the light transmitting diffuser while the island of the lead frame is being conveyed onto the light transmitting diffuser, the light passes through the light transmitting diffuser and moves upward. Spread to By emitting light from the light-transmitting diffuser that supports the island of the lead frame from below, the upper camera can clearly observe the silhouette of the island in a bright background and accurately determine the bonding position of the chip. Can be.

[0007]

(Embodiment 1) FIG. 1 is a perspective view of a lead frame transfer device according to Embodiment 1 of the present invention.
2A is a partial perspective view of the lead frame transfer device, FIG. 2B is a partial perspective view showing an inner side surface of a movable transfer rail of the lead frame transfer device, and FIG. 3 is a lead frame transfer device. FIG. 4 is a partial cross-sectional view of the lead frame transport device.

First, the overall structure of a lead frame transport device will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes a base plate, on which two guide rails 2 are arranged. A slide guide 3 is slidably fitted to each of the two guide rails 2. A plate 4 is provided to connect the two slide guides 3.

At both ends of the plate 4, brackets 5 are erected. The upper ends of the two brackets 5 are connected by a movable transfer rail 6a. A fixed transfer rail 6b is provided in parallel with the movable transfer rail 6a. The fixed transport rail 6b is fixed by a bracket 7. Movable transport rail 6a and fixed transport rail 6b
Between them, backup plates 8A are mounted at two places. This backup plate 8A will be described later.

A rod 11 of a cylinder 10 is connected to the center of the plate 4. Rod 1 of cylinder 10
When 1 protrudes and retracts, the plate 4 moves back and forth in the Y direction, and the size of the interval B between the movable transport rail 6a and the fixed transport rail 6b is adjusted. That is, the cylinder 10 is a moving unit that moves the movable transport rail 6a with respect to the fixed transport rail 6b in order to change the interval B between the movable transport rail 6a and the fixed transport rail 6b.

In FIG. 1, reference numeral 12 denotes a lead frame, which is mounted on a movable transport rail 6a and a fixed transport rail 6b (hereinafter, referred to as a "transport path"). The lead frame 12 is transported downstream (to the right) on the transport path by the transport means 14 moving in the X direction. The transfer means 14 includes the chuck 13 having an openable / closable claw.
At 3, the end of the lead frame 12 is held. A chip 36 is bonded to the island 12a of the lead frame 12 by means described later. In the present invention,
The transport direction of the lead frame 12 is defined as an X direction, and a direction orthogonal to the X direction is defined as a Y direction.

A paste application means 20 is provided above the downstream side of the transport path. The paste applying means 20 includes:
Syringe 2 containing paste for bonding chips inside
2, and a nozzle 23 for applying paste is attached to the lower end of the syringe 22. The syringe 22 is connected to a Z table (not shown) by a bracket 21 and can move up and down. A camera 25 for observing the island 12a of the lead frame 12 to determine the paste application position is integrally attached to the paste application unit 20.

When the lead frame 12 is transported to the position of the paste application means 20 on the transport path, the syringe 22 performs a lowering / upward operation, and applies the paste 24 onto the island 12a of the lead frame 12 by the nozzle 23. At this time, the backup plate 8A supports the lead frame 12 from below.

In FIG. 4, the camera 25 is connected to a recognition unit 50. The recognition unit 50 recognizes the position of the island 12 a of the lead frame 12 from the image captured by the camera 25, and outputs the position information to the control unit 51. The control unit 51 controls the transporting unit 14 based on the position information of the island 12a to align the nozzle 23 with the island 12a, and sends a command to the paste applying unit 20 to apply the paste to a predetermined position of the island 12a. .

A chip bonding means 30 is provided on a transport path downstream of the paste applying means 20. The bonding means 30 includes a bonding head 32 mounted on a Y table 31. The bonding head 32 moves in the Y direction along the Y table 31. A collet 3 is provided at the lower end of the bonding head 32.
3 is attached. A camera 34 for observing the lead frame 12 is integrally attached to the bonding head 32. The camera 34 is also connected to the recognition unit 50 and the like similarly to the camera 25 (see FIG. 4).

The recognition unit 50 recognizes the position of the island 12a from the image captured by the camera 34, and
Navel location information is sent. The control unit 51 controls the transporting unit 14 and the bonding unit 30 based on the positional information to position the chip 36 adsorbed on the collet 33 and the island 12a, and moves the chip 36 to the island 12a.
It is bonded at a predetermined position above. Y on the side of the transport path
A chip supply unit 35 having a wafer for supplying chips 36 is provided below the table 31.

The bonding head 32 is a Y table 3
1 moves to a position directly above the chip supply unit 35, and the collet 33 moves up and down to pick up the chip 36. Then, it is again moved on the transport path by the Y table 31 and stands by. When the lead frame 12 is transported to the position of the bonding means 30 on the transport path,
After the position of the island 12a is recognized by the camera 34 and the positioning is performed, the collet 33 performs a descending / elevating operation to bond the chip 36 onto the paste 24 applied to the island 12a. At this time, the backup plate 8A supports the lead frame 12 from below.

Next, the arrangement structure of the backup plate 8A will be described with reference to FIG. As described above, the backup plate 8A is used when the paste is applied and when the chip 36
This is for supporting the lead frame 12 from below so that the lead frame 12 does not rattle at the time of bonding, and one having a different size depending on the type of the lead frame 12 is used interchangeably. As shown in FIG. 2, the backup plate 8A is manufactured with a width dimension corresponding to the size of the lead frame 12, and the backup plate 8A
Are provided with two grooves 16 in the width direction (Y direction).

One end of two rod-shaped holders 9 is connected to the movable transfer rail 6a in a horizontal posture.
The other end side is a through hole 1 provided in the fixed conveyance rail 6b.
7 is inserted. Therefore, while the holder 9 is fixed to the movable transfer rail 6a, the movable transfer rail 6a is fixed to the fixed transfer rail 6b in the width direction of the lead frame 12 (Y
Direction). The backup plate 8A is detachably mounted between the movable transfer rail 6a and the fixed transfer rail 6b by fitting the groove 16 on the lower surface to the holder 9.

When the backup plate 8A is mounted on the holder 9, the movable transport rail 6a is advanced by moving the cylinder 10 toward the backup plate 8A and pressed against the side end face thereof, thereby moving the movable transport rail 6a.
a and the distance B between the fixed transport rail 6b and the lead frame 12
Is set to match the interval of. That is, the backup plate 8A also serves as a spacing member for adjusting the distance between the movable transfer rail 6a and the fixed transfer rail 6b to the width of the lead frame 12.

2 and 3, the upper surface of the front end of the backup plate 8A is partially cut away, and the light transmitting diffuser 8a is attached to the cut portion. The light transmitting diffuser 8a is made of light-colored ground glass or acrylic resin. When bonding the chip 36 to the island 12a, the island 12a of the lead frame 12 stops on the light transmitting diffuser 8a and is supported by the light transmitting diffuser 8a from below. In FIG. 4, a suction hole 44 is formed at the center of the light transmitting diffuser 8a. The suction hole 44 is connected to a suction system (not shown) through a groove 52 a as a suction path and a pipe 53, and the chip 36 is connected to the island 12.
When mounted on a, the island 12a is sucked and fixed so that the island 12a does not rattle.

In FIGS. 2 and 3, a cable 41 is mounted on the side surface of the movable transfer rail 6a via a bracket 40. Many optical fibers 42 are housed in the cable 41. As shown in FIG. 3, the optical fiber 42 extends from the cable 41 into the movable transport rail 6a, and its distal end faces the entire side surface of the light transmitting diffuser 8a as shown in FIG. 2B. The cable 41 is connected to the light source unit 43, and the light emitted from the light source unit 43 passes through the optical fiber 42 and passes through the light transmitting diffuser 8a.
Is radiated to the side surface and is incident on the inside. That is,
The cable 41 and the light source unit 43 are light source means for irradiating the light transmitting diffuser 8a with light. The broken arrow L indicates light.

In FIG. 4, the chip supply unit 35 is horizontally moved in the X and Y directions by the movable table 37 so that the collet 33 can pick up a predetermined chip 36 on the chip supply unit 35, and moves under the backup plate 8A. Approach to the side.

Here, the light transmitting diffuser 8a, which is a part of the backup plate 8A, is also used as a bright background when observed by the camera 34, and the cable 41 is connected to the side surface of the movable transfer rail 6a to provide a chip. The distance D between the upper surface of the supply unit 35 and the lower surface of the backup plate 8A is made as small as possible, and the level of the chip supply unit 35 is made as high as possible, so that the chip supply unit 35 can approach the lower surface of the backup plate 8A. Therefore, the vertical movement stroke S when the collet 33 of the bonding head 32 picks up the chip 36 of the chip supply unit 35 is shortened as much as possible, thereby shortening the takt time required for picking up. The chip 36 can be bonded at a high speed by shortening. Also, when observing the island 12a with the camera 25 to detect the application position of the paste 24, the light transmitting diffuser 8a becomes a bright background.

This die bonding apparatus has the above configuration, and its operation will be described below with reference to the drawings. In FIG. 1, the lead frame 12 is transported downstream on a transport path. The paste 24 is applied to the island 12a of the lead frame 12 by the paste applying means 20. The lead frame 12 to which the paste has been applied is transported by the transport means 14 to the position of the bonding means 30, where the chip 36 is bonded onto the paste 24 of the island 12a. Then, the lead frame 12 for which bonding has been completed is transported to the next step.

The island 1 of the lead frame 12 will now be described.
Prior to bonding the chip 36 to 2a, the island 12a is observed by the camera 34, and the chip 36
Is recognized. In this case, the light emitted from the light source unit 43 in FIG.
1 and enter the inside of the light transmitting diffuser 8a. Then, the light passes through the inside of the light transmitting diffuser 8a and is uniformly diffused upward, and the light transmitting diffuser 8a emits surface light with uniform brightness. The light emitted upward from the light transmitting diffuser 8a passes through the opening of the lead frame 12 and enters the camera 34. Therefore, the island 12a is provided with the light transmitting diffuser 8
The dark silhouette is clearly observed with a being a light background. In this case, the upper surface of the light transmitting diffuser 8a is in contact with the island 12a placed thereon, and the light transmitting diffuser 8a emits light from the closest distance toward the island 12a. Observable.

Based on the observation result, the chip 36
Is determined, and the chip 36 is mounted at a predetermined bonding position with high positional accuracy and bonded.

(Embodiment 2) FIG. 5 is a partial cross-sectional view of a lead frame transport device according to Embodiment 2 of the present invention.
In FIG. 5, the upper surface of the cut-off portion of the backup plate 8B is a tapered surface 45, and the plate-shaped light transmitting diffuser 8b is mounted on the tapered surface 45. The tapered surface 45 is a reflection surface that reflects the light L. Light L is emitted from the optical fiber 42 toward the tapered surface 45, is reflected upward by the tapered surface 45, and is diffused by the light transmitting diffuser 8b. Therefore, the silhouette of the island 12a can be more clearly observed with the camera 34.

The light transmitting / diffusing body 8b is formed with a suction hole 54 for sucking the island 12a. The suction hole 54 communicates with a space 55 between the light transmitting / diffusing body 8b and the tapered surface 45. are doing. The space 55 is connected to a suction system (not shown) via a pipe 53. Therefore, when the suction system is operated, the island 1 of the lead frame 12 is
2a is adsorbed on the light transmitting / diffusing body 8b by the adsorption hole 54,
Fixed.

(Embodiment 3) FIG. 6 is a partial sectional view of a lead frame transporting apparatus according to Embodiment 3 of the present invention.
In FIG. 6, the upper surface of the cutout portion of the backup plate 8C has a tapered surface 46 with a downward slope toward both sides, and the light transmitting diffuser 8c is mounted on the tapered surface 46. The tapered surface 46 is a reflection surface that reflects the light L. The cable 41 is mounted on the movable transfer rail 6a and the fixed transfer rail 6b. Light L is emitted from the optical fibers 42 on both sides toward the tapered surface 46, is reflected upward by the tapered surface 46, and is diffused by the light transmitting diffuser 8 c. Therefore, the island 12a can be more clearly observed with the camera 34.

At the center of the light transmitting diffuser 8c, the suction hole 5 is provided.
6 are formed. At the center of the backup plate 8C, a support portion 57 that supports the light transmission / diffusion body 8c around the suction hole 56 from below is projected. This support part 57
This prevents the light transmitting diffuser 8c from being deformed downward by the pressure during bonding. Reference numeral 58 denotes a suction path formed inside the backup plate 8C.
And a pipe 53 connected to a suction system (not shown). Therefore, when the suction system is activated, the island 12a
Is sucked and fixed in the suction hole 56.

(Embodiment 4) FIG. 7 is a partial plan view of a lead frame transport device according to Embodiment 4 of the present invention, and FIG. 8 is a partial sectional view of the same. The leading end of the backup plate 8D is a light transmitting diffuser 8d,
A plurality of light sources 47 such as LEDs as light source means are arranged side by side on both sides of the light transmitting diffuser 8d in the 2 ′ transport direction (X direction). The lead frame 12 'has a plurality of islands 12a' in the width direction.

The light emitted from the light source 47 enters the light transmitting diffuser 8d and is diffused. Therefore Island 1
The silhouette of 2a 'can be clearly observed with the camera 34.
The light transmitting diffuser 8d has suction holes 59 formed at positions corresponding to the plurality of islands 12a '.
0, connected to a suction system (not shown) via a pipe 53.

(Embodiment 5) FIG. 9 is a partial sectional view of a lead frame transporting apparatus according to Embodiment 5 of the present invention.
The upper surface of the backup plate 8E is a tapered surface 48 having a downward slope toward both sides, and the light transmitting diffuser 8e is mounted on the tapered surface 48. Also, the light transmitting diffuser 8
A plurality of light sources 47 are arranged on both sides of e. The light L emitted from the light source 47 is reflected by the tapered surface 48, enters the light transmitting diffuser 8d, and is diffused. Therefore, the silhouette of the island 12a can be clearly observed with the camera 34.

In the second to fifth embodiments, the configuration other than the illustration is the same as that of the first embodiment. Further, in each of the above embodiments, a part of the backup plate is a light transmitting diffuser, but the entire backup plate may be a light transmitting diffuser. Further, a backup plate (left backup plate in FIG. 1) provided below the paste applying means 20 may also constitute the same light transmission / diffusion body as in the above-described embodiment. The paste can be correctly applied to a predetermined position by clearly observing with the camera 25. The parts to be recognized on the lead frame are positioning holes and leads, etc.
Parts other than islands may be used.

[0036]

As described above, according to the present invention, the silhouette of the island of the lead frame can be clearly observed by the camera, so that the bonding position of the chip can be accurately determined based on the observation result, and the position of the chip can be accurately determined. Can be well bonded to islands.

Further, since the light source means does not have to be disposed directly below the backup plate, the light source means can be effectively used immediately below the backup plate as an entry space for the chip supply unit. Therefore, the upper surface of the chip supply unit is disposed below the backup plate. By arranging the chip supply unit so as to be as close as possible, the up / down stroke of the chip pickup means such as a collet can be shortened, and the chip can be picked up at that high speed and bonded to the lead frame.

[Brief description of the drawings]

FIG. 1 is a perspective view of a lead frame transport device according to a first embodiment of the present invention.

FIG. 2 (a) is a partial perspective view of a lead frame transfer device according to the first embodiment of the present invention; and (b) a portion showing an inner side surface of a movable transfer rail of the lead frame transfer device according to the first embodiment of the present invention. Perspective view

FIG. 3 is a partial plan view of the lead frame transport device according to the first embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of the lead frame transport device according to the first embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of a lead frame transport device according to a second embodiment of the present invention.

FIG. 6 is a partial cross-sectional view of a lead frame transport device according to a third embodiment of the present invention.

FIG. 7 is a partial plan view of a lead frame transport device according to a fourth embodiment of the present invention.

FIG. 8 is a partial cross-sectional view of a lead frame transport device according to a fourth embodiment of the present invention.

FIG. 9 is a partial cross-sectional view of a lead frame transport device according to a fifth embodiment of the present invention.

[Explanation of symbols]

 6a Movable transport rail 6b Fixed transport rail 8A, 8B, 8C, 8D, 8E Backup plate 8a, 8b, 8c, 8d, 8e Light transmitting diffuser 12, 12 'Lead frame 12a, 12a' Island 24 Paste 30 Bonding means 34 Camera 35 chip supply section 36 chip 41 cable 42 optical fiber 43 light source unit 47 light source

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kenichi Takakura 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5F047 AA11 BA21 BB11 BB16 FA32 FA36 FA79

Claims (1)

[Claims] 1. A die bonding apparatus comprising: bonding means for bonding a chip to a lead frame; a camera for observing the lead frame at a bonding position from above; and a chip supply unit for supplying the chip to the bonding means. The transfer means for transferring the lead frame to the bonding means includes two parallel transfer rails for transferring the lead frame, and a backup plate between the transfer rails and supporting the lead frame from below during chip bonding. A die bonding apparatus characterized in that a part or all of the backup plate is formed of a light transmitting diffuser for transmitting and diffusing light, and light source means for inputting light into the light transmitting diffuser is provided. .