JP2886712B2 - 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 bonding apparatus used in, for example, a mounting step in a process of manufacturing a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, for example, when a semiconductor chip is attached to a heat sink in a process of manufacturing a semiconductor laser diode, the semiconductor chip is held on a collet of a die bonding apparatus, and a load is applied to the held semiconductor chip. While being fixed to a predetermined position of the heat sink, the collet is detached from the semiconductor chip and then attached to the heat sink.

A first conventional example of a die bonding apparatus used in such a manufacturing process will be described with reference to FIG. FIG. 6 is a perspective view of a main part. The bonding arm 1 is swingably supported by a pivot bearing 3 provided on a support member 2 fixed to a frame (not shown). At one end of the bonding arm 1, a suction collet 5 for holding the semiconductor chip 4 is provided at the tip, and a cam follower 6 is provided at the other end, and one end of a spring 7 stretched between the frame and a frame (not shown). Has been fixed.
A cam 9 driven by a motor 8 is in contact with the outer peripheral surface of the cam follower 6. The spring 7 is provided so as to rotate the bonding arm 1 clockwise around the pivot bearing 3 at all times, and the suction collet 5 is used to rotate the cam 9 contacting the outer peripheral surface of the cam follower 6. It is provided to move up and down while drawing an arc.

A heat sink 10 for attaching the semiconductor chip 4 is fixed to a frame (not shown) in the middle of a vertical movement stroke of the suction collet 5 by the cam 9. The stroke of the suction collet 5 is limited. The lower end of the suction collet 5 presses the mounting surface of the heat sink 10 on the semiconductor chip 4 with a load based on the contraction force of the tensioned spring 7.

[0005] With this configuration, the heat sink 10 is fixed to the frame, the semiconductor chip 4 is held at the lower end of the suction collet 5 by means (not shown), and then the motor 8 is rotated so that the cam 9 is rotated. Then, the bonding arm 1 is moved so that the position of the cam follower 6 whose outer peripheral surface is in contact with the rotation of the cam 9 draws an arc around the pivot bearing 3 and rotates upward from below. Is rotated downward. Then, the semiconductor chip 4 held by the suction collet 5 is brought into contact with the mounting surface of the heat sink 10 fixed in the middle of the stroke of the suction collet 5, and the cam 9 is further rotated to reduce the compression force of the spring 7. Only the base load acts between the mounting surface of the heat sink 10 and the semiconductor chip 4.

However, in the above-mentioned first conventional example, the semiconductor chip 4 can be brought into pressure contact with the heat sink 10 with a small sliding resistance due to the support by the pivot bearing 3 and a relatively small and stable light load. However, since the movement of the suction collet 5 is an arc movement centering on the pivot bearing 3, variations in the position where the heat sink 10 is fixed, the position of the mounting surface of the heat sink 10 and the thickness dimension, etc., cause the positioning accuracy and the tip inclination accuracy. In such a case, a short circuit between the electrodes may be caused, or the mounting accuracy may not be maintained, which has been a problem in improving the yield of products.

Next, the second conventional die bonding apparatus is used.
Will be described with reference to FIG. FIG. 7 is a schematic configuration diagram of a main part. A movable holding section 13 is provided on the movable side of a linear motion bearing 12 provided on a frame 11, and the suction collet 5 is mounted on the movable holding section 13.
The movable holding unit 13 is urged upward by a spring 14 in the figure. An electromagnetic solenoid coil 15 is provided on the frame 11, and by energizing the electromagnetic solenoid coil 15, the movable holding unit 13 urged upward by the spring 14 is urged downward. The movable holding unit 13 moves forward and backward by changing the value of the current and voltage applied to the electromagnetic solenoid coil 15, and the suction collet 5 moves forward and backward accordingly. On the other hand, the heat sink 10 is attached to the frame 11 such that the mounting surface to which the semiconductor chip 4 is pressed is located at a position in the middle of the stroke in which the lower end of the suction collet 5 advances and retreats.

Since the heat sink 10 is fixed to the frame 11 and the semiconductor chip 4 is held at the lower end of the suction collet 5 by means (not shown), the electromagnetic solenoid coil 15 is excited, The movable holding portion 13 is pushed down in a direction opposite to the force of the movable holding portion 13. Then, the semiconductor chip 4 is brought into contact with the mounting surface of the heat sink 10 and the electromagnetic solenoid coil 1
By setting the values of the current and voltage applied to the semiconductor chip 4, a predetermined load is applied to the mounting surface of the heat sink 10 and the semiconductor chip 4.
Act between.

However, in the above-mentioned second conventional example, since the suction collet 5 is moved by linear motion using the spring 14, the electromagnetic solenoid coil 15, and the linear motion bearing 12, the semiconductor chip 4 is heat-sinked with relatively high precision. Although it can be pressure-bonded to the semiconductor chip 4, the semiconductor chip 4 cannot be stably bonded due to an increase in load variation at a light load of 30 g or less due to sliding resistance or the like in the linear motion bearing 12 that performs linear guide, and the semiconductor chip 4 is damaged. There was a possibility that it would be.
For example, a chip such as a semiconductor laser diode having a small thickness has been a particular problem in improving the yield of products.

[0010]

In light of the above, light-weight bonding is problematic in view of the fact that it is difficult to improve the yield of products due to variations in load, accuracy in positioning, chip inclination, and the like. The purpose of the present invention is to achieve stable bonding with a small load variation even with a light load bonding, and to achieve sufficient mounting accuracy with little displacement and chip inclination. It is another object of the present invention to provide a bonding apparatus capable of improving product yield.

[0011]

SUMMARY OF THE INVENTION A bonding apparatus according to the present invention includes a support portion which is linearly moved in a vertical direction and is provided at a middle position of the movement so as to be able to stop, and which can be pivoted by a pivot bearing. An arm which is supported and has a holding portion for holding the semiconductor chip at one end, a load adjusting portion for adjusting a downward load on the holding portion, a stopper for holding the arm at a substantially horizontal position, and And a detector for detecting the upward rotation of the held arm and stopping the movement of the support.

[0012]

The bonding apparatus constructed as described above
The arm is held pivotally by a pivot bearing and can hold the semiconductor chip in the holding portion at one end, and the arm holding the semiconductor chip is held in a substantially horizontal position by a stopper, and the arm holding the semiconductor chip is linearly moved downward. Move to
When the semiconductor chip contacts the mounting surface and a predetermined load is applied to the semiconductor chip and the arm starts to rotate by the pivot bearing, this movement is detected by the detection unit, and the downward movement of the arm is stopped based on the detection result. It is configured as follows. For this reason, even in bonding with a light load, the arm is supported by the pivot bearing, so that the load can be stably bonded with little variation in load, and a predetermined load is applied to the semiconductor chip linearly instead of in an arc motion. Therefore, a sufficient mounting accuracy can be obtained with little displacement and chip inclination, and the yield of products can be improved.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. 1 is a schematic configuration diagram, FIG. 2 is a perspective view of a main part, and FIGS. 3 to 5 are partial front views for explaining a bonding operation. Referring to FIG.
For example, a transport rail 22 is provided on the ceiling of the work space, and the slider 23 travels along the transport rail 22 in the X-axis direction, that is, in the horizontal direction. A mount head 24 is vertically mounted on the slider 23, and the slider 23 is configured such that the mount head 24 can reciprocate between a working unit 25 and a stock unit 26 provided at a lower part of a working space. ing.

The mount head 24 includes a slider 2
3 is fixed to the frame member 28 of the drive mechanism 27 so as to be suspended. The drive mechanism 27 includes a ball screw unit 29 that has both ends supported by a frame member 28 and has a rotation axis in the Z-axis direction, that is, the vertical direction.
Is rotated forward and reverse by the motor 30, thereby moving the slide table 31 in the Z-axis direction (vertical direction), and stopping the motor 30 to stop the slide table 31 at an arbitrary position. ing. A support member 32 having a substantially Z-shaped cross section is fixed to the vertical surface of the slide table 31 so as to protrude therefrom.

A notch 33 is formed in the horizontal portion 32a of the support member 32.
A bonding arm 35 supported at a fulcrum by a pivot bearing 34 is provided. At one end of the bonding arm 35, a suction collet 36, which is a semiconductor chip holding portion that can be connected to or disconnected from a vacuum source (not shown) to hold and separate an object at the lower end, is provided. At the other end, there is provided a load adjusting portion 37 for adjusting the load of the lower end portion of the suction collet 36 in a vertically downward direction. The load adjusting portion 37 is screwed and extended to the other end of the bonding arm 35. Adjuster 37
The load 39 is adjusted by rotating the screw 39 having the large diameter head 38 and the balancer 40 screwed to the screw 39 to change the position from the fulcrum.

Further, a stopper screw 41 is screwed into the horizontal portion 32a of the support member 32 located at one end of the bonding arm 35 from the lower surface side into a screw hole provided through the horizontal portion 32a. The hemispherical tip of the stopper screw 41 protruding toward the upper surface abuts against the lower surface at one end of the bonding arm 35 to stop the bonding arm 35 from rotating to the right in the figure, and to be substantially horizontal. To be maintained. Stopper screw 4
By turning the knob 1, the inclination of the bonding arm 35 can be adjusted, and the protrusion of the stopper screw 41 toward the upper surface can be fixed by tightening the nut 42 screwed to the stopper screw 41. .

Still further, the horizontal portion 32 of the support member 32
A displacement sensor 43 is fixed to the upper surface of the substrate a, and a target 44 is fixed to the lower surface on one end side of the bonding arm 35 at a position facing the displacement sensor 43, and a gap 45 between the displacement sensor 43 and the target 44 is formed. When it changes, the change is detected by the displacement sensor 43, and the rotation of the motor 30 is controlled by the output of the displacement sensor 43. For example, while the gap 45 between the displacement sensor 43 and the target 44 set in advance is maintained, the motor 30 continues to rotate so as to lower the slide table 31.
3, the motor 30 is controlled to stop rotating. Reference numeral 46 denotes a semiconductor chip, 47 denotes a heat sink, and 47a denotes an attachment surface on which the semiconductor chip 46 is attached.

In the above-described structure, the bonding operation is performed in the mounting step as follows. First, the heat sink 47 is mounted horizontally at a predetermined position of the working unit 25 by means not shown, with the mounting surface 47a facing upward. Further, the slider 23 is moved in the horizontal direction along the transport rail 22 so that the mount head 24 stops at a preset position of the stock portion 26 where the semiconductor chip 46 is stocked. Then motor 3
0, the slide table 31 is lowered, and the semiconductor chip 46 in the stock portion 26 is held at a substantially horizontal position.
Is held at the lower end by vacuuming. At this time, the semiconductor chip 46 is held horizontally by the suction collet 36.

Then, with one semiconductor chip 46 held by the suction collet 36, the motor 30 is driven to raise the slide table 31, and further the slider 23
Is moved in the horizontal direction so that the semiconductor chip 46 is located directly above the mounting surface 47a of the heat sink 47 as shown in FIG.

Next, the slide table 31 is gradually lowered by driving the motor 30, and the semiconductor chip 46 held by the suction collet 36 is brought into contact with the mounting surface 47a of the heat sink 47 as shown in FIG.

Further, by lowering the slide table 31, the bonding arm 35 held substantially horizontally by the stopper screw 41 as shown in FIG. 5 is moved to a position where the lower end of the suction collet 36 at one end is stopped. The fulcrum supported by the support 34 is lowered, and the one end provided with the suction collet 36 starts rotating upward with respect to the fulcrum. By this rotation, the holding of the bonding arm 35 by the stopper screw 41 is released, and the vertical downward load of the lower end of the suction collet 36 adjusted in advance by the load adjusting unit 37 causes the attachment of the semiconductor chip 46 and the heat sink 47. It is added to the contact portion with the surface 47a. At the same time, the rotation of the bonding arm 35 causes the displacement sensor 43 to move.
The gap 45 between the target and the target 44 starts to expand, and the gap 45
Is immediately detected by the displacement sensor 43, and the rotation of the motor 30 is stopped based on the detection result.

Subsequently, the evacuation by the vacuum source is stopped, the holding of the semiconductor chip 46 by the suction collet 36 is released, and then the motor 30 is driven to raise the slide table 31. Then, the heat sink 47 having the semiconductor chip 46 attached to the attachment surface 47a is removed from a predetermined position of the working section 25 by means not shown, and the bonding operation is completed.

According to this embodiment constructed as described above, the bonding arm 35 is swingably supported by the pivot bearing 34, and is adjusted in advance by the load adjusting section 37 so as to be vertically lower than the lower end of the suction collet 36. Can be set to a desired light load.
Even if the chip 6 is a chip such as a semiconductor laser diode having a small thickness, the chip hardly breaks. Further, the semiconductor chip 46 held at the lower end of the suction collet 36 is brought into contact with the attachment surface 47 a of the heat sink 47. , Mounting surface 47a
It can be attached by a stable load with little variation in the direction perpendicular to the direction. In addition, since the attachment of the semiconductor chip 46 to the heat sink 47 is not performed while performing an arc movement, sufficient positional accuracy and mounting accuracy can be obtained without causing a short-circuit between electrodes due to a small displacement or inclination of the semiconductor chip 46. And the product yield can be improved.

In the above embodiment, the slide table 31 is moved linearly in the vertical direction. However, the slide table 31 may be moved linearly in the vertical direction. The detection of the rotation of the bonding arm 35 due to the adjustment of the load of the 37 or the change in the gap is not limited to the above-described ones, and the present invention can be implemented by appropriately changing the range without departing from the gist. .

[0025]

As is apparent from the above description, according to the present invention, the arm supported by the pivot bearing and holding the semiconductor chip at one end and substantially horizontally maintained is linearly moved downward. The arm is configured so that the downward movement of the arm is stopped at the same time that a predetermined load is applied to the semiconductor chip. As a result, sufficient mounting accuracy can be obtained with a small inclination of the chip and the yield of products can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention.

FIG. 2 is a perspective view of a main part of FIG.

FIG. 3 is a first partial front view for explaining a bonding operation according to an embodiment of the present invention.

FIG. 4 is a second partial front view for explaining a bonding operation according to one embodiment of the present invention.

FIG. 5 is a third partial front view for explaining a bonding operation according to the embodiment of the present invention.

FIG. 6 is a perspective view of a main part showing a first conventional example.

FIG. 7 is a schematic configuration diagram of a main part showing a second conventional example.

[Explanation of symbols]

 27 ... Drive mechanism 30 ... Motor 31 ... Slide table 32 ... Support member 34 ... Pivot bearing 35 ... Bonding arm 36 ... Suction collet (holding part) 37 ... Load adjustment part 41 ... Stopper screw 43 ... Displacement sensor (detection part) 44 ... Target 45: gap 46: semiconductor chip 47: heat sink 47a: mounting surface

Claims (1)

(57) [Claims] 1. A support portion which is linearly moved in the vertical direction and is provided at a middle position of the movement so as to be stoppable, and is pivotally supported by the support portion by a pivot bearing and holds a semiconductor chip at one end. An arm having a holding portion, a load adjusting portion for adjusting a downward load on the holding portion,
A stopper for holding the arm at a substantially horizontal position, and a detection unit for detecting the upward rotation of the holding unit of the arm held by the stopper and stopping the movement of the support unit. A bonding apparatus.