JPH09115931A - Diebonder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce damage for chips as little as possible and to easily realize minimizing of installing space and making chips transfer in higher speed. SOLUTION: A diebonder picks up chips 14 contained in many recess parts 14 formed in a tray 12 with X-Y mobility by a collet 17 clamping from a surface and the chips 14 are mounted at a predetermined mounting position after posture of these chips 14 is corrected. In the step an image recognizing means 19 in which rear of the chips is shot and recognized as an image by an optical system 18 under the condition of being clamped by the collet 17 at a pausing position R on the way of transfer between a picking up position P of the chips 14 by the collet 14 and a mounting position Q and a controlling means 21 in which posture of the chip 14 is corrected by the collet 17 being finely adjusted in the direction of XY θfrom data of the image recognition by an adjusting mechanism 20.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a die bonder,
More specifically, the present invention relates to a die bonder used for manufacturing semiconductor devices and the like, in which a large number of chips housed in a tray are surface-adsorbed by a collet to be picked up and mounted after the attitude of the chips is adjusted.

[0002]

2. Description of the Related Art For example, in the manufacture of a semiconductor device, a large number of semiconductor pellets (hereinafter, referred to as chips) collectively formed from a semiconductor wafer are once housed in a tray as an alignment jig, and the chips are put in the tray. A die bonder is used to mount the lead frame on a lead frame at a predetermined mounting position (for example, JP-A-57-53).
950).

Some die bonders of this type have a structure as shown in FIGS. 6 and 7, for example. That is, X
A tray 2 to be described later is fixed on the Y table 1 and arranged so as to be movable in the XY directions. The tray 2 is an alignment jig in which a large number of recesses 3 are formed in a predetermined arrangement relationship, and the chips 4 divided from the semiconductor wafer are housed in each recess 3 in the previous step. On the other hand, a transport rail 5 is arranged at a position separated from the tray 2, and the lead frame 6 is intermittently transported on the transport rail 5 in a direction indicated by an arrow in the figure at a constant pitch.

An alignment stage 7 is arranged between the tray 2 and the lead frame 6, the attitude of the chip 4 taken out of the tray 2 is corrected by the alignment stage 7, and the attitude-corrected chip 4 is moved from the alignment stage 7. It is mounted on the lead frame 6. The alignment stage 7 has a claw 8 that positions the chip 4 placed on the stage in four or two directions.

The chip transfer from the tray 2 to the alignment stage 7 and the chip transfer from the alignment stage 7 to the lead frame 6 are performed by using dedicated jigs called collets 9a and 9b.

Each of the collets 9a and 9b has a suction hole at the tip of the nozzle, and the chip 4 is surface-sucked by drawing a vacuum from the suction hole. The chip transfer from the tray 2 to the alignment stage 7 is performed by the first collet 9a that is vertically and horizontally movable between the two, and the chip transfer from the alignment stage 7 to the lead frame 6 is performed between the two. The second collet 9b, which is vertically movable and horizontally movable, interlocks with each other.

In the conventional die bonder, the chips 4 in the tray 2 are mounted on the lead frame 6 by the following procedure.

First, the chip 4 housed in the recess 3 of the tray 2 is placed at the pickup position P by the operation of the XY table 1, and then the chip 4 is surface-adsorbed by the first collet 9a. Here, the chip 4 is the tray 2
Since it is accommodated in the concave portion 3 with a margin, there is rattling in the concave portion 3. Due to this rattling, the attitude of the chip 4 sucked and held by the first collet 9a also varies. Therefore, after the pickup, the attitude of the chip 4 is corrected by the alignment stage 7.

Chip 4 picked up from tray 2
While being sucked and held by the first collet 9a, it is transferred to the alignment stage 7 and placed on the alignment stage 7. Then, the tip 4 released from the first collet 9a is pinched by the claws 8 from four directions and the posture is corrected to perform positioning.

The chip 4 whose posture is corrected by the alignment stage 7 is again surface-adsorbed by the second collet 9b, and is transferred to the mount position Q on the lead frame 6 while being adsorbed and held by the second collet 9b. . The chip 4 sucked and held by the second collet 9b is placed and mounted at a predetermined mounting position on the lead frame 6.

As described above, the operations of picking up and transferring the chip 4 by the first collet 9a, correcting the attitude of the chip 4 on the alignment stage 7, transferring the chip 4 by the second collet 9b, and mounting are sequentially repeated.

[0012]

By the way, in the conventional die bonder, since the attitude of the chip 4 is corrected by the alignment stage 7, the alignment stage 7 must move the chip from the first collet 9a to the second collet 9b. I won't. Therefore, not only when the first collet 9a picks up from the tray 2, but also when the second collet 9b picks up from the alignment stage 7, the chips 4 come into contact with each other, and the chips 4 are greatly damaged.

Further, since the alignment stage 7 has to be arranged between the tray 2 and the lead frame 6, it is difficult to reduce the cost of the product because of the equipment cost, and the alignment stage 7 cannot be manufactured. Existence,
Also, due to the securing of the moving area of the tray 2 (see the broken line in FIG. 7) accompanying this, it is difficult to bring the tray 2 and the lead frame 6 close to each other, and it is also difficult to reduce the installation space. .

Further, as described above, the alignment stage 7 moves the chip 4 from the first collet 9a to the second collet 9a.
It is also difficult to transfer the chip 4 from the tray 2 to the lead frame 6 at high speed because it is necessary to switch to the b and it is difficult to bring the tray 2 and the lead frame 6 close to each other.

Therefore, the present invention has been proposed in view of the above problems, and an object of the present invention is to reduce the damage to the chip as much as possible, reduce the installation space, and speed up the chip transfer. It is to provide a die bonder that can easily realize the above.

[0016]

As a technical means for achieving the above object, the present invention picks up chips, which are housed in a large number of recesses formed in an XY movable tray, by surface adsorption by a collet. In a die bonder that mounts the chip at a predetermined mounting position after correcting the attitude of the chip, the chip remains attached to the collet at the stop position during the transfer from the pickup position of the chip to the mounting position by the collet. An image recognition means for recognizing an image by picking up the back surface with an optical system, and a control means for correcting the attitude of the chip by finely adjusting the collet in the XYθ directions by an adjusting mechanism based on the image recognition data are provided. And

In the optical system, at least one mirror is arranged above the XY movement area of the tray below the stop position during the chip transfer by the collet, and the mirror rear surface of the chip is provided from a direction other than below the stop position. It is desirable to be able to take an image with a camera.

Further, it is desirable that a chip having a thickness smaller than the recess depth of the tray is sucked by a collet having a flat chip suction surface.

Further, the chip suction surface is sucked by a flat collet whose chip suction surface is larger than the chip outer shape,
It is desirable to make the surface state of the collet different from each other so that the chip suction surface and the chip back surface have a desired contrast.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a die bonder according to the present invention will be described with reference to FIGS. The die bonder of the present invention has a structure as shown in FIGS. As in the conventional case, the tray 12 is placed on the XY table 11 and XY is placed.
It is arranged so that it can move in any direction. The tray 12 has a large number of recesses 1
3 is an alignment jig in which the semiconductor wafers 3 are formed in a predetermined arrangement relationship, and the chips 14 divided from the semiconductor wafer are housed in the respective recesses 13 in the previous step. On the other hand, a transport rail 15 is arranged at a position separated from the tray 12, and the lead frame 16 is intermittently transported on the transport rail 15 in a direction indicated by an arrow in the figure at a constant pitch.

Further, a collet 17 having a suction hole at the tip of the nozzle and sucking the chip 14 on the surface by evacuation from the suction hole is arranged between the tray 12 and the lead frame 16 so as to be vertically movable and horizontally movable. The collet 17 picks up the chip 14 from the tray 12 and transfers it to the lead frame 16 for mounting. This collet 17 does not require replacement of the chip 14 in the conventional alignment stage 7 (see FIGS. 6 and 7),
A single chip is sufficient because it is only temporarily stopped for image recognition of the chip 14 during chip transfer.

In this die bonder, at the stop position R during the transfer of the chip 14 by the collet 17 from the pick-up position P to the mount position Q, the back surface of the chip remains in the state of being sucked by the collet 17 (for example, a CCD camera or the like). ), An image recognition means 19 for recognizing an image by picking up an image by an optical system 18, and a fine adjustment of the collet 17 in the XYθ directions by an adjusting mechanism 20 based on the image recognition data obtained by the image recognition means 19. And a control means 21 for correcting the posture of the head.

In the case of the present invention, the conventional alignment stage 7 (see FIGS. 6 and 7) is not arranged between the tray 12 and the lead frame 16, so they are arranged close to each other. It is possible to On the other hand, in order to capture an image of the back surface of the chip sucked and held by the collet 17 at the stop position R during the transfer of the chip, it is necessary to dispose a camera below it. However,
As described above, the tray 12 is arranged close to the lead frame 16, and the tray 12 is the XY table 1.
Since there is an XY movement area of the tray 12 because it can be moved by 1, the camera is arranged below the stop position R during the chip transfer by the collet 17 and the back surface of the chip is directly imaged by the camera. Is difficult.

Therefore, below the stop position R during the chip transfer by the collet 17, above the XY movement region of the tray 12 (see the broken line in FIG. 2), a mirror having the first and second mirrors 22 and 23 built therein. The cylinder 24 is disposed orthogonal to the chip transfer direction of the collet 17 and parallel to the transfer direction of the lead frame 16. In the lens barrel 24, the first
The mirror 22 is tilted at an angle of about 45 °, and the second mirror 23 is tilted at a side of the first mirror 22 at an angle of about 45 ° so as to face each other. Further, a camera 26 is arranged above the second mirror 23 so as to be connected to the lens barrel 24 and via a zoom lens 25. As a result, below the stop position R during the chip transfer by the collet 17, the back surface of the chip is imaged by the camera 26 using the first and second mirrors 22 and 23.

The first mirror 22 and the second mirror 23
Between the second mirror 23 and the second mirror 23, the half mirror 27 is arranged at the same angle, and the light source 28 is arranged above the half mirror 27, and the back surface of the chip is illuminated by the light source 28.

In the die bonder of the present invention, the chips 14 in the tray 12 are mounted on the lead frame 16 by the following procedure.

First, the chip 14 housed in the recess 13 of the tray 12 is placed at the pickup position P by the operation of the XY table 11, and then the chip 14 is surface-adsorbed by the collet 17. Here, since the chip 14 is accommodated in the recess 13 of the tray 12 with a margin, there is rattling in the recess 13. Due to this rattling, the attitude of the tip 14 sucked and held by the collet 17 also varies, so the attitude of the tip 14 is corrected as described later.

The chip 14 picked up from the tray 12 is transferred while being sucked and held by the collet 17,
Stop the collet 17 at the stop position R during chip transfer.
To stop. At this time, the first mirror 22 is located below the back surface of the chip sucked and held by the collet 17. In this stopped state, the zoom lens 25 is used to magnify the image through the first and second mirrors 22 and 23, the back surface of the chip is imaged by the camera 26, and the image recognition means 19 recognizes the image. Then, the chip transfer by the collet 17 is resumed to transfer the chip 14 to the mount position Q.
By finely adjusting the collet 17 in the XYθ directions by the adjusting mechanism 20 according to a command from the control means 21 based on the image recognition data obtained by the image recognition means 19 between the image recognition of the chip 14 and the mounting. The attitude of the tip 14 is corrected. The chip 14 whose posture has been corrected in this manner is mounted on the lead frame 16 at a predetermined mounting position at the mount position Q by the collet 17 and mounted.

Here, when the attitude of the chip 14 is corrected before being sucked by the collet 17, for example, even if the attitude of the chip 14 is corrected in the recess 13 of the tray 12, the desired chip 14 is placed at the pickup position P. When the tray 12 is moved in the XY direction for
Since 4 is rattling in the concave portion 13 to cause a positional deviation, it is difficult to properly correct the posture. Temporarily, the concave portion 1 of the tray 12
Even if the tip 14 can be maintained in a properly posture-corrected state within 3, when the tip 14 is sucked by the collet 17, since the collet 17 has a flat shape, the tip 14 is particularly in the θ direction. Since the chip 14 is often displaced, it is difficult to mount the chip 14 on the lead frame 16 with high accuracy.

Therefore, as described above, the attitude of the chip 14 is corrected by finely adjusting the collet 17 in the XYθ directions while being sucked and held by the collet 17, so that the chip 14 can be accurately attached to the lead frame 16. It can be mounted in a positioned state.

As described above, the pickup of the chips 14 from the tray 12 by the collet 17, the collet 1
7 sequentially recognizes the image of the back surface of the chip at the stop position R during the chip transfer, corrects the attitude of the chip 14 by the collet 17 based on the image recognition data, and mounts the chip 14 on the lead frame 16 by the collet 17. .

As shown in FIG. 4A, the tray 1 is
When handling a tip 14 having a thickness smaller than the depth of the concave portion 2, the tip of the collet must be inserted into the concave portion 13, and a flat collet 17 having a suction surface smaller than the outer shape of the tip must be used. In this case, in the screen m obtained by the image recognition of the back surface of the chip at the stop position R during the chip transfer, FIG.
A binarized image in which the contrast with the surroundings is set by shining the back surface of the chip as shown in FIG.

Further, as shown in FIG. 5A, when handling a chip 14 having a thickness larger than the depth of the recess of the tray 12, unlike the case described above, the suction surface has a flat shape larger than the chip outer shape. Collet 17 can be used. Therefore, in the screen m obtained by image recognition of the back surface of the chip at the stop position R during chip transfer, the collet suction surface is mirror-finished as shown in FIG. A binarized image with is set.

[0034]

According to the present invention, after the chip is picked up by the collet, the attitude of the chip is corrected by recognizing the image of the back surface of the chip at the stop position during the chip transfer while being sucked and held by the collet. Since the chip whose posture has been corrected is mounted by the collet, there is no need to change the tip of the chip by the collet, and the contact with the chip by the collet is only during pickup, so damage to the chip can be suppressed to the necessary minimum. it can.

Further, since the alignment stage is not required between the tray and the lead frame, the facility can be simplified and the product cost can be reduced, and the tray and the lead frame can be brought close to each other. Since it is easy, the installation space can be reduced.

Furthermore, as described above, since it is easy to change the holding of the chip by the collet and to make the tray and the lead frame close to each other by omitting the alignment stage, it is possible to transfer the chip from the tray to the lead frame at high speed. it can.

[Brief description of the drawings]

FIG. 1 is a plan view showing a schematic configuration of a die bonder of the present invention.

FIG. 2 is a side view of the die bonder of FIG.

3 is a schematic configuration diagram showing an optical system constituting the die bonder of FIG.

4A is a cross-sectional view showing a state in which a suction surface is suctioned by a collet whose suction surface is smaller than the chip outer shape, and FIG. 4B is a diagram showing a binarized image obtained when the collet in FIG. 4A is used.

5A is a cross-sectional view showing a state where a suction surface is suctioned by a collet whose suction surface is larger than the chip outer shape, and FIG. 5B is a diagram showing a binarized image obtained when the collet in FIG.

FIG. 6 is a plan view showing a schematic configuration of a conventional die bonder.

7 is a side view of the die bonder of FIG.

[Explanation of symbols]

 12 Tray 13 Recessed portion 14 Chip 17 Collet 18 Optical system 19 Image recognition means 20 Adjustment mechanism 21 Control means P Pickup position Q Mount position R Stop position during transfer

Claims (4)

[Claims] 1. A die bonder for picking up a chip housed in a large number of recesses formed in an XY movable tray by a collet to pick up the surface, correcting the posture of the chip, and mounting the chip at a predetermined mounting position. At the stop position during the transfer from the pickup position of the chip to the mount position by the collet, the image recognition means for recognizing the image by imaging the back surface of the chip with the optical system while being attracted to the collet, and the image recognition data thereof. Adjust the collet based on
A die bonder comprising: a control unit that adjusts the attitude of the chip by finely adjusting in the Yθ direction. 2. The optical system arranges at least one mirror above a XY movement area of a tray below a stop position during chip transfer by a collet, and the mirror backs the chip back surface except below the stop position. The die bonder according to claim 1, wherein an image can be taken by a camera from a direction. 3. The die bonder according to claim 1, wherein a chip having a thickness smaller than the depth of the recess of the tray is sucked by a collet having a flat chip suction surface. 4. The chip suction surface is sucked by a flat collet whose chip suction surface is larger than the chip outer shape, and the surface state of the collet is made different so that the chip suction surface and the chip back surface have a desired contrast. The die bonder according to claim 1, wherein: