JPS6233321Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a positioning device for semiconductor pellets, and more particularly to a positioning device that can easily accommodate pellets having various sizes and shapes.

Semiconductor devices such as ICs, LSIs, and transistors are
A semiconductor pellet (also called a die) with a predetermined circuit formed on a silicon substrate is bonded to a predetermined position on a lead frame (dice bonding), and the terminal pad on this pellet is bonded to the lead on the lead frame. Perform wire bonding to connect the
After mounting the pellet part with resin, the lead frame is divided into individual semiconductor devices, and the final product is finished with a product with a predetermined number of leads protruding from the side of the resin mount part. pass

Among the above manufacturing steps, the following method is generally adopted in the step of bonding the pellets onto the lead frame.

That is, first, a large number of semiconductor devices are fabricated on one wafer at once, and then the boundaries of each device are scribed. The wafer thus formed is temporarily bonded onto a stretchable sheet, and then divided into individual semiconductor elements by cracking (those divided in this way are called pellets), and the sheet is then placed in its place. By stretching the pellets by a certain amount, the gap between the pellets, which were only separated but in close contact with each other, is widened. Thereafter, in the die bonding apparatus, the pellets are picked up one by one by a pellet suction collet that moves back and forth between a predetermined bonding position on the lead frame, and are carried onto the lead frame for bonding.

Examples of such pellet adsorption collets include, for example, Japanese Utility Model Application No. 140743/1983;
There are some disclosed in Japanese Patent No. 106233, and most of them are designed to adsorb pellets using vacuum pressure.

The pellet suction collet described above is designed to suction and hold pellets by storing them in a rectangular recess formed on its lower surface.
If the orientation of the pellet is out of alignment with the direction of the recess, even if the planar position of the pellet is controlled to be directly above the pellet, not only will it not be possible to accommodate and hold the pellet in the recess, but the pellet will be This results in the bottom surface coming into contact and destroying the element pattern. As explained earlier, when a wafer temporarily bonded to a stretchable sheet is cracked and then stretched, the orientation of each pellet may not be uniform during the stretching. This means that the pellet is not picked up correctly as described above, and even if it is picked up, it is not properly bonded to the lead frame.

In order to solve this problem, instead of transporting the pellets picked up by the pellet suction collet as they are to the bonding position, as shown in Figure 1, a positioning device is interposed between the pick-up position and the bonding position, and the pellets are expanded and contracted. A method has been proposed in which pellets are picked up from a bonding sheet, are once lowered onto a positioning device, their orientation is correctly corrected, and then transported to a bonding position. The present invention relates to improvements in positioning devices used in such techniques.

Next, the configuration and problems of an example of a conventional positioning device will be explained based on FIG. 2.

Around a cylindrical support 2 having a flat pellet positioning surface 1 on the top surface, a pellet holder 4 having a claw 3 on the top is placed.
Book arms 4 are provided at equal intervals so as to surround the pedestal 2. Each of the claws 3 is a plate-shaped member whose base end is fixed to the top of the arm 4 by a screw 5 and extends in the horizontal direction, and whose tip end reaches above the positioning surface 1. . Further, the tip portion 3a of this claw 3 is formed in a straight line, and this portion 3a is formed into a rectangular pellet P.
Press each side of . The base ends of the arms 4 are connected to a drive device (not shown), so that they can swing as indicated by arrows. Further, a stopper bolt 6 whose tip can come into contact with the cylindrical outer surface of the support base 2 is screwed into a suitable intermediate portion of each arm 4.

When a pellet carried by a collet (not shown) is placed approximately at the center of the pellet positioning surface 1, the arm 4 is swung, and the claw 3
move toward the center of positioning surface 1 all at once,
Press each side of the pellet P to position it correctly. When positioning is completed, the claw 3 retreats to its original position, and the pellet whose orientation has been corrected is
It is again picked up by the collector, transported to a predetermined bonding position, and bonded. When the size or shape of the pellet to be positioned changes, the amount by which the stopper bolt screwed into the arm 4 is tightened is adjusted to adjust the amount by which the pawl 3 can move. That is, for example, when positioning larger pellets,
Further screw in all four stopper bolts 6. The reverse is true when positioning smaller pellets. Furthermore, when changing from a square pellet to a rectangular pellet, the amount of screwing in of the stopper bolts related to the pawls facing each other on the diameter of the positioning surface 1 is different from the amount of screwing in of the other stopper bolts.

As is clear from the above, the conventional pellet positioning device has a problem in that when the size and shape of the pellet to be positioned changes, it is quite difficult to adjust the movement of the claws accordingly. That is,
It takes a lot of time and skill to adjust the four separate stopper bolts as desired while checking the relationship between the claws. Among the conventional positioning devices of this type, there are those shown in Japanese Patent Publication No. 56-52450, in which the claw drive method is changed from the one shown in Fig. 2, and the one shown in Japanese Patent Publication No. 57-63838. There is also a pair of claws with V-shaped or L-shaped tips, such as the one shown in the publication, but in any case, in order to regulate the moving end of the claw, it is necessary to The present invention is similar to the example shown in FIG. 2 in that it employs stopper members that are related to each other, but when the size and shape of the pellet to be positioned changes, it is difficult to adjust the amount of movement of the claws accordingly. In addition, when trying to restrict the movement of each pawl by using a stopper associated with each pawl, phenomena such as chattering that adversely affect the positioning device and the pellet may occur when the stoppers come into contact with each other. There is also another problem.

The present invention was devised in view of the above circumstances, and its purpose is to greatly adjust the amount of movement of the positioning claw in response to changes in the size and shape of the pellet to be positioned. It is an object of the present invention to provide a new pellet positioning device that can be easily performed.

In order to achieve this purpose, in this invention,
Next, we are taking technical measures.

That is, a cam follower is attached to each of two or more claw members which are configured to elastically move toward the pellet placement portion at the center of the positioning surface, and the claw members simultaneously abut against the cam followers of the claw members. A second cam capable of reciprocating is provided; an arm is provided with one end rotatably supported relative to a fixed fulcrum, and a spring tends to elastically rotate this arm in one direction; Further, the intermediate portion of a crank having two arms is rotatably supported with respect to a moving fulcrum at the intermediate portion of the arm, and a cam follower is attached to one arm of the crank, and the cam follower is in contact with the cam follower. a first cam is provided, and when the first cam is driven, the crank swings; the other arm of the crank and the second cam are connected by a motion transmission means; A micrometer spindle is brought into contact with an appropriate part of the arm so as to counteract the elastic force of the spring.

The arm does not rotate unless the micrometer spindle is moved axially. Therefore, the fulcrum of movement of Kotoki's arm is actually at a fixed position. In this state, when the first cam is rotated,
A crank having a cam follower in contact with the cam follower swings, and this movement is transmitted to the movement of the pawl member via the motion transmitting means or the second cam, and the pellet placed on the positioning surface is moved by the pawl member. The direction can be determined correctly by the movement of. The pawl member is caused to reciprocate on a line extending radially from the center of the positioning surface depending on the shape of the second cam, and its movement stroke mainly depends on the shape of the first cam. In other words, the pawl member of the device of the present invention is not defined by the stopper as in the conventional example, but is determined by how much the cam follower attached to the arm of the crank is moved by the first cam (or,
In addition, it depends on how much the cam follower of the pawl member is moved by the second cam). Therefore, there is no impact or chattering caused by the claw member directly contacting the stopper as in the prior art, and this does not adversely affect the device or the pellets.

When the spindle of the micrometer is moved axially, the arm rotates a certain angle about the fixed fulcrum, so that the moving fulcrum takes a position slightly shifted from the above case. However, since the position where the first cam is provided has not changed, when the first cam is rotated, the crank will swing in a range different from that described above. This means that
This means that the range in which the claw member reciprocates is also slightly shifted compared to the above case. in this way,
The pellet positioning device according to the present invention can easily change the range of motion of the claw member by slightly rotating the arm supporting the crank by operating the micrometer, so the size of the pellet to be positioned can be easily changed. Even if the degree shape changes, this can be accommodated very easily. Furthermore, since a micrometer is used, reproducibility in changing the movement range of the claw member is ensured.

Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 3 is a perspective view schematically showing the overall configuration of an embodiment of the present invention.

The device of the present invention has a positioning section A that positions a pellet on a positioning surface using four claws, and a control section B that drives the claws in the positioning section A and controls the movement thereof. There is.

First, the pellet positioning section A will be explained.

Positioning surface 11 on which the pellet to be positioned in the center is placed (for clarity of the configuration of the present invention,
In FIG. 3, it is shown by phantom lines. ), a total of two pairs of claw members 13 and 14 are provided around the positioning surface 11, one pair each facing each other on the diameter thereof, so as to be able to reciprocate in the X direction and the Y direction, respectively. In this embodiment, slide blocks 16 are slidably supported by guide bars 15 that are fixed at one end to a suitable fixing member (not shown) and extend in the X and Y directions, and
This slide block 16 is constructed by fixing to the upper surface thereof tapered horizontal plate-shaped claws 17 and 18 whose tips face toward the center of the positioning surface 11.
The tips of the guide bars 15 are formed to have a large diameter to prevent the slide blocks 16 from moving too far toward the center of the positioning surface. Further, each slide block 16 is always urged to elastically move toward the center of the positioning position by fitting a compression coil spring 19 to the guide bar 15 on the outside thereof. . Also, each slide block 1
A roller-shaped cam follower 20 rotatable around a vertical axis is attached to the lower surface of the slide block 16, and is driven by a second cam 21, which will be described next, to reciprocate the slide block 16 by a predetermined amount. play the role of

Below the positioning surface 11, a rotary shaft 22 having an axis coincident with the center of the positioning surface is provided, and at the upper end thereof a rotary shaft 22 is provided which cooperates with a cam follower 20 attached to the slide block 16. Two cams 21 are attached. In this embodiment, among the four claw members 13 and 14,
Although the claw members 13 that oppose each other in the Y direction and the claw members 14 that oppose each other in the Y direction are driven by separate systems, in the drawing, for the sake of simplicity, a pair of second cams 21 that oppose each other in the Y direction are shown. Only those for driving the claw members 13 are shown. This second cam 2
1 is constituted by a horizontal plate-shaped member whose center is fixed to the top of the rotating shaft 22 and extends an equal distance on both sides of this shaft in the radial direction, as clearly shown in FIG. includes an inclined cam surface 2 whose distance from the axis of the rotating shaft 22 gradually changes.
3 is formed. As is clear from FIG. 6, when the second cam 21 rotates counterclockwise around the rotating shaft 22, the cam surface 23 pushes the cam follower 20 in contact with it against the elastic force of the compression coil spring 19. As a result, the distance between the pair of claw members 13 facing each other in the Y direction increases. This indicates that the tips of the claws 17 are retreating from the center of the positioning surface. On the other hand, when the second cam 21 rotates clockwise, the cam follower 20 or the claw member 13 is moved by the elasticity of the compression coil spring 19 a certain distance toward the center of the positioning surface according to the shape of the cam surface 23. This indicates that the tip of the claw 17 is moving forward.

The base end of an arm 24 is fixed to the lower part of the rotating shaft 22, and this arm 24 is connected to a control section B, which will be described next, by a connecting rod 25, which is a motion transmission means. .

As shown in FIGS. 3 and 4, the control section B is provided with an arm 26 whose base end is rotatably supported with respect to a fixed fulcrum C of a suitable fixed member. At the moving fulcrum D in the middle of this arm 26, there is approximately
A crank 29 is rotatably supported at its intermediate portion, which is composed of two arms 27 and 28 that intersect at an angle of 90 degrees. One arm 27 of this crank 29
A roller-shaped cam follower 30 is attached to the cam follower 30, which is brought into contact with a cam surface 32 on the outer periphery of a first cam 31 that rotates. Further, one end of the connecting rod 25 is connected to the other arm 28 of the crank 29.

Further, a contact surface 33 provided at an appropriate portion of the arm 26, that is, in the illustrated example, at the tip thereof.
The tip of a spindle 35 of a micrometer 34 whose main body is fixed to a suitable fixing member is brought into contact with the micrometer. In the illustrated example, since the spindle 35 is brought into contact with the spindle 35 downward, the arm 26 is held against the spring 36.
It is best to hang it upwards. Regarding the crank 29, its cam follower 3
It is preferable that the spring 37 be biased so that the first cam 31 always elastically contacts the cam surface 32 of the first cam 31. Further, the shape of the cam surface of the first cam 31 is such that a region a is short and a region b is far from the center of rotation.

Next, the operation of this embodiment will be explained.

When the amount of protrusion of the spindle 35 of the micrometer 34 is fixed at a certain amount, the arm 26 is
During operation of the device, there is no movement, and the moving fulcrum D also takes a certain fixed position. In this state, when the first cam 31 is rotated once, the crank 29 swings about the moving fulcrum D, and this movement is transmitted to the second cam 21 of the positioning section A via the connecting rod 25. or the claw member 13, and the claw 17
moves forward and backward once toward the center of the positioning surface, so that the pellet placed on the positioning surface can be correctly oriented.

Next, if the spindle 35 of the micrometer 34 is made to protrude further, and the arm 26 is rotated slightly lower than in the above case, the position of the moving fulcrum D will be as shown by the imaginary line in FIG. It moves slightly downward, and the entire crank 29 tilts slightly clockwise in FIG. Therefore, the position of the lower end of the arm 28, that is, the end of the connecting rod 25 on the arm 28 side is slightly shifted to the left in FIG. In this state, when the first cam 31 is rotated once, the crank 29 or the pawl member 13 makes a predetermined movement in the case described above, that is, when the arm 26 is in the state shown by the solid line in FIG. However, as described above, as the position of the end of the connecting rod 25 is shifted, the range of movement of the crank 29 or the pawl member is shifted. Looking at this with respect to the movement of the arm 24 attached below the rotating shaft 22 having the second cam 21 at the upper end,
As shown in FIG. 7, when the arm 26 is in the state shown by the solid line in FIG. 4, the arm 26 rotates in the range indicated by the symbol c, and on the other hand, the arm 26 is in the state shown by the imaginary line in FIG. At this time, it rotates within the range indicated by the symbol d. This means that the forward end of the claw can be changed very easily just by changing the amount of protrusion of the micrometer spindle. In the case of this embodiment, when the size of the pellet to be positioned increases, the spindle can be made to protrude, and when the size of the pellet to be positioned becomes small, the spindle can be retracted.

In this embodiment, among the four claw members, each pair of diametrically opposed claw members is driven by a separate system. Although only one of these systems is shown in the drawing, in reality, another set of control unit B consisting of an arm 26, a crank 29, a first cam 31, and a micrometer 34 is prepared, and the rotation shaft 2 is
2 is a double shaft, a second cam and an arm for the claw member 14 facing in the X direction are attached to this, and the control section B is connected to this. In this way, for example, the positioning of rectangular pellets can be easily handled.

In addition, if the shape of the pellet to be positioned is constant, the second cam 21 shown in the drawings may be formed into, for example, a cross shape, and the four cam surfaces formed at the ends of the second cam 21 may be formed into four claw members. It is only necessary to contact the cam followers of the two at the same time.

It goes without saying that the scope of the present invention is not limited to the embodiments shown in the drawings.

For example, in the positioning section A, the rotating shaft 22
The second cam 21 to be attached to the upper end of the second cam 21 may be in the form of a roller, while the cam follower 20 that is driven in contact with the second cam 21 may be in the form of an inclined surface. Further, the roller-shaped cam follower 20 in the illustrated example
and 30 do not particularly need to be in the form of rollers, and may simply be in the form of protrusions that come into contact with the cam surface. Furthermore, as a motion transmission means for transmitting the movement of the crank 29 to the arm 24 of the rotating shaft 22, for example, a double wire consisting of an inner wire and an outer wire is used in addition to the connecting rod as shown in the illustrated example. You can also do that.

As explained above, the pellet positioning device of the present invention has the unique effect of being able to respond immediately and extremely easily to changes in the size and shape of pellets to be positioned.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the pellet pickup and bonding system that is the premise of the present invention, FIG. 2 is a perspective view showing a conventional example, and FIG. 3 is a perspective view showing the overall configuration of the present invention. FIG. 4 is a front view of the control unit, FIG. 5 is a sectional view taken along the - line in FIG. 3, and FIG.
The figure is a plan view explaining the operation of the positioning section, and FIG.
FIG. 5 is a diagram corresponding to FIG. 5 for explaining the unique effects of the present invention. 11... Positioning surface, 13, 14... Claw member,
20...Cam follower, 21...Second cam, 25
...Motion transmission means (connecting rod), 2
6... Arm, 27, 28... Arm, 29... Crank, 30... Cam follower, 31... First cam, 34... Micrometer, 35... Spindle, 36... Spring, C... Fixed fulcrum ,D...Moving fulcrum.

Claims (1)

[Claims for Utility Model Registration] A semiconductor pellet positioning device characterized by the following features: two or more pawl members elastically movable toward a pellet placement section in the center of a positioning surface; A cam follower is attached to each of the claw members, and a second cam is provided which can simultaneously abut the cam follower of the claw member and reciprocate the claw member, and an arm is provided with one end rotatably supported relative to a fixed fulcrum. , a spring tends to elastically rotate this arm in one direction, and the middle part of a crank having two arms is rotatably supported with respect to a moving fulcrum in the middle part of this arm. , a cam follower is attached to one arm of the crank, and a first cam is provided that abuts the cam follower, so that when the first cam is driven, the crank swings; The arm and the second cam are connected by a motion transmission means, and the spindle of the micrometer is brought into contact with an appropriate part of the arm so as to counteract the elastic force of the spring.