Patent Application
20190295878
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2018-054311, filed Mar. 22, 2018, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a push-up device and a push-up method for a semiconductor device.
During an assembly operation of a semiconductor element, a conveyance device peels off a diced semiconductor element (semiconductor chip) from an adhesive sheet and mounts the semiconductor element to a lead frame. In the conveyance device, there is provided a push-up device which pushes up the semiconductor chip.
Embodiments provide a push-up device and a push-up method for a semiconductor device by which manufacturing accuracy is improved.
In general, according to one embodiment, there is provided a push-up device of a semiconductor device which includes a lifting table which includes a push-up surface, the push-up surface positioned to face a rear surface of an adhesive sheet to push up a semiconductor element bonded to a front surface of the adhesive sheet from the rear surface of the adhesive sheet, and a plurality of convex portions disposed on an outer periphery of the push-up surface of the lifting table to abut corner portions of the semiconductor element through the rear surface of the adhesive sheet when the semiconductor element is pushed up by the lifting table, such that the adhesive sheet peels off from the semiconductor element at locations further outward from the corner portions when the semiconductor element is pushed up by the lifting table.
According to one embodiment, there is provided a method of pushing up a semiconductor device using a lifting table having a plurality of lifting blocks, each of which includes a push-up surface for pushing up a semiconductor element bonded to a front surface of an adhesive sheet from a rear surface of the adhesive sheet. The push-up method includes pushing up corner portions of the semiconductor element using a plurality of convex portions disposed on an outer periphery of the push-up surface of the lifting table to initially peel off the adhesive sheet from the semiconductor element at locations further outward from the corner portions, and sequentially raising or lowering at least two of the lifting blocks after the adhesive sheet is initially peeled off to further peel off the adhesive sheet from an outer side of the semiconductor element toward a center of the semiconductor element.
Hereinafter, an embodiment will be described in detail with reference to the drawings.
First, a conveyance device including the push-up device of a semiconductor chip will be described with reference
Generally, the conveyance device 1 includes a push-up device 100 and a conveyance mechanism 200.
The push-up device 100 pushes a semiconductor chip 5 up from an adhesive sheet 4 to peel off a part from the adhesive sheet 4. The conveyance mechanism 200 adsorbs the pushed-up semiconductor chip 5, and conveys the chip onto a target position (for example, the lead frame).
The push-up device 100 includes the lifting table 2, a lifting device 3, a drive control unit 6, a sheet pressing device 10, and a table moving device 11. The lifting table 2 pushes up the semiconductor chip 5 from the adhesive sheet 4. The lifting device 3 individually elevates a plurality of lifting blocks (described below) of the lifting table 2. The drive control unit 6 controls the driving of the lifting device 3. The sheet pressing device 10 applies a tension force to the adhesive sheet 4 which bonds the semiconductor chip 5 on the lifting table 2. The table moving device 11 moves the lifting table 2 to a place immediately below where the semiconductor chip 5 is picked up.
The conveyance mechanism 200 includes a transfer collet 7, a suction unit 8, and a conveyance actuator 9. The transfer collet 7 adsorbs the pushed-up semiconductor chip 5 and picks up the chip to be peeled off from the adhesive sheet 4. The suction unit 8 applies a suction force with which the semiconductor chip 5 is adsorbed to the transfer collet 7. The conveyance actuator 9 moves the adsorbed semiconductor chip 5 to the lead frame (not illustrated) for example.
In addition, a control unit 12 controls the respective portions of the push-up device 100 and the conveyance mechanism 200. Further, the above device configuration is an example configuration in which the lifting table 2 is moved to a place immediately below the designated semiconductor chip 5. However, on the contrary, the designated semiconductor chip 5 may be moved to a place immediately below the lifting table 2 by moving the adhesive sheet 4. In addition, the example below describes a configuration in which the semiconductor chip 5 is pushed up. However, the pushing direction is not limited to the upward direction but, for example, a horizontal direction or a downward direction may be employed.
Hereinafter, the respective portions of the conveyance device 1 will be described in detail. First, the configuration of the lifting table 2 and the lifting device 3 will be described with reference to
The lifting table 2 includes a plurality of lifting blocks, each of which elevates. In this embodiment, four lifting blocks 21, 22, 23, and 24 will be given as an example. Frame-shaped lifting blocks 23, 22, and 21 are disposed to face outward in the horizontal direction to encircle the rectangular lifting block 24 which is disposed at the center of the lifting table 2. For example, in a case where the assembled lifting blocks 21, 22, 23, and 24 are disposed about the same center, these blocks are concentrically shaped in a rectangular shape. Of course, the frame shape is not limited to a rectangular shape as long as the lifting blocks are formed of the same frame shape in a magnitude relation, and fitted in a radial direction of the frame. In addition, the number of lifting blocks is not limited to four.
The lifting block 24 is disposed at the center of the table, and includes a push-up surface of a rectangular shape. The lifting block 24 is supported and elevated by a support portion 24a which extends from the lifting device 3.
The lifting block 23 is formed as a rectangular frame shape which surrounds the outer side of the lifting block 24. The lifting block 23 is supported and elevated by a support portion 23a which extends from the lifting device 3. Similarly, the lifting block 22 and the outermost lifting block 21 of the same frame shape are disposed to face and surround the lifting block 23 from the outer side. Even the lifting blocks 21 and 22 are supported and elevated by support portions 21a and 22a extending from the lifting device 3.
As illustrated in
A convex portion 25 is provided at each corner of the lifting table 2, that is, each corner of the upper surface of the lifting block 21 which is disposed on the outermost side. The convex portion 25 is formed in a semispherical shape such as an ellipsoidal shape or a circular shape as illustrated in
In addition, the outermost lifting block 21 is formed such that the shape of at least the upper portion is formed in a square trapezoidal shape. In other words, the side surface on the outer side from the convex portion 25 is inclined to form a slope surface 21b. With the slope surface 21b, the adhesive sheet 4 that is peeled off and inclined downward does not come into contact with the corners of the upper surface of the lifting block 21.
The lifting device 3 individually elevates the lifting blocks 21, 22, 23, and 24 using, for example, a drive source such as a hydraulic actuator and a pneumatic actuator, or a drive source such as a linear motor, an electric motor, and a motor of a link mechanism. The lifting device 3 elevates each of the lifting blocks 21, 22, 23, and 24 by a command of the drive control unit 6 based on a control signal from the control unit 12.
The transfer collet 7 is provided with a suction surface 7a on a leading edge, and is provided with an opening 7b at its inner side. The suction surface 7a is desirably formed to have a surface size similar to a chip size so as to not apply a load locally on the semiconductor chip 5 when the semiconductor chip 5 is peeled off from the adhesive sheet 4. The opening 7b may be formed by one opening in the center of the suction surface 7a, or may be provided by a plurality of openings in a distributed manner on the surface. The opening 7b is connected to the suction unit 8 through a suction passage 7c which passes through the transfer collet 7. As the suction unit 8, for example, a suction pump is used to suck the air in the suction passage 7c of the transfer collet 7, and makes the opening 7b enter into a negative pressure state. The semiconductor chip 5 abuts the opening 7b when adsorbed to the suction surface 7a.
The conveyance actuator 9 includes an arm portion which moves the transfer collet 7 vertically and horizontally. The conveyance actuator 9 positions the suction surface 7a of the transfer collet 7 relative to the semiconductor chip 5 by the control of the control unit 12 so that the semiconductor chip 5 can be adsorbed onto the suction surface 7a. Thereafter, the conveyance actuator 9 moves and transfers the chip by the arm portion to a designated place, for example, the lead frame, and while doing so peels off the adsorbed semiconductor chip 5 from the adhesive sheet 4.
When the lifting table 2 is pushed up, the adhesive sheet 4 starts peeling off from the end portion of the semiconductor chip as described below. The sheet pressing device 10 prevents the adhesive sheet 4 from floating so as to make the semiconductor chip 5 easily peeled off.
In addition, the sheet pressing device 10 may apply tension to make the semiconductor chip 5 easily peeled off from the adhesive sheet 4. The tension may pull both ends of the adhesive sheet 4, and may suck a rear surface side (a non-mounting surface of the semiconductor chip) of the adhesive sheet 4. Alternatively, the adhesive sheet 4 may be not applied with tension as long as the peeling is accelerated by a restoring force (that is, an elastic force or retractility) of the adhesive sheet 4 when the semiconductor chip 5 is pushed up.
Push-up Operation and Conveyance Operation
Next, the push-up operation of the convex portion 25 of the lifting block 21 with respect to the semiconductor chip 5 and the peeling of the adhesive sheet 4 will be described with reference to
First, as illustrated in
Next, the lifting table 2 rises by a predetermined block projecting amount during a first lifting phase to push up the semiconductor chip 5 (Step S2).
The semiconductor chip 5 is pushed up together with the convex portion 25 of the lifting block 21 by the first lifting of the lifting table 2. In general, a stress in a case where the rectangular semiconductor chip 5 is peeled off from the adhesive sheet 4 is focused on the corners of the chip. Then, the convex portion 25 is provided at the corners of the outermost lifting block 21, and the adhesive sheet 4 is slightly peeled off at the side end (particularly, the corner of the rectangular shape) of the semiconductor chip 5. During this first push-up, the adhesive sheet 4 is slightly peeled off from the corners of the semiconductor chip 5, and the stress on the corner of the chip can be reduced during the next push-up. Then, sequentially, the lifting blocks 22 to 24 are pushed up to move the peeling location of the semiconductor chip 5, and the adhesive sheet 4 is peeled off in a ring shape toward the inside of the chip. Therefore, a partial stress is moved toward the inside of the semiconductor chip 5.
Therefore, when the semiconductor chip 5 is peeled off from the adhesive sheet 4, the generated stress is dispersed in stages and in time series, so that the stressed area moves toward the center of the chip. Therefore, the lifting table 2 according to the embodiment can reduce damage on the end portion and the inner portion of the semiconductor chip 5 unlike a push-up pin of the related art which is pushed up at one time to peel off the semiconductor chip 5 from the adhesive sheet 4.
In addition, when the peeling of the adhesive sheet 4 from the semiconductor chip 5 by the convex portion 25 of the lifting block 21 occurs slightly at the end portion, the peeling location starts to move inside from the corner of the semiconductor chip 5 at the subsequent push-ups. Therefore, it is possible to reduce the stress on the end portion of the semiconductor chip 5. When actually measured, a distance L of the peeled adhesive sheet 4 is about 0<L<0.5 mm from the corner (or the outer peripheral end; the side of the chip) of the semiconductor chip 5 to the top portion of the convex portion 25. Preferably, the adhesive sheet is peeled off by 0.25 mm from the corner of the semiconductor chip 5 to the top portion of the convex portion 25. The distance L is changed in accordance with a thickness of the semiconductor chip 5 and a strength of the silicon substrate.
For example, as illustrated in
In addition, a first rising distance of the lifting table 2 to peel off the semiconductor chip 5 from the adhesive sheet 4, that is, a block projecting amount h of the pushed-up lifting block 21, will be described. As illustrated in
Next, as illustrated in
Subsequently, as illustrated in
Further, as illustrated in
The semiconductor chip 5 pushed up by the lifting block 24 is adsorbed onto the transfer collet 7 to be lifted up, peeled off from the adhesive sheet 4, and conveyed up to a predetermined position (Step S6). Thereafter, the lifting block 24 is lowered, and returns to the standby state illustrated in
Operations and Effects of Embodiment
The conveyance device 1 described above first pushes up the semiconductor chip 5, and the adhesive sheet 4 is slightly peeled off from the corners of the semiconductor chip 5 by the convex portion 25 which is provided in the outermost lifting block 21. Thereafter, the semiconductor chip is sequentially pushed up by the push-up surfaces of the lifting blocks 21 to 24 with sequentially reduced pushing areas so as to progress the peeling in stages. Therefore, the semiconductor chip is pushed up using the surfaces of the lifting blocks 21 to 24 while gradually reducing the bonded area of the semiconductor chip 5 and the adhesive sheet 4 over a plurality of times compared to the related art in which the semiconductor chip is pushed up at one time using a pressing pin, so that the stress applied to the semiconductor chip when the adhesive sheet 4 is peeled can be dispersed. Therefore, according to the conveyance device 1, it is possible to avoid breaking and cracking of the outer peripheral end of the semiconductor chip 5, especially in configurations where the outer peripheral end is thinner than that of the semiconductor chip of the related art which does not break even when using the push-up pin.
Further, since the stress is applied over a surface, the stress is not focused on a spot. Therefore, it is possible to prevent cracks in the semiconductor chip 5. With this configuration, after the semiconductor chip 5 is produced as a semiconductor element, it is possible to keep a high-quality performance throughout its product lifetime while avoiding degradation in durability which is caused by inner cracks. In addition, the push-up device according to this embodiment can be applied to various devices, and thus can be used for the existing conveyance device by being replaced with a pick-up mechanism of the push-up pin of the related art.
Modifications of Lifting Operation in Lifting table of Embodiment
Next, a modification of the lifting operation of the lifting blocks 21 to 24 of the lifting table 2 will be described with reference to
First, as illustrated in
Next, as illustrated in
Next, as illustrated in
Next, as illustrated in
Subsequently, as illustrated in
In this example, the outer lifting blocks of the lifting blocks 21, 22, and 23 are sequentially lowered. The bonded area of the semiconductor chip 5 and the adhesive sheet 4 is reduced to the half or less when the semiconductor chip 5 is adsorbed to the transfer collet 7. The semiconductor chip 5 pushed up by the lifting block 24 is adsorbed onto the transfer collet 7, peeled off from the adhesive sheet 4, and conveyed up to a predetermined position (Step S16). Thereafter, the lifting block 24 is lowered, and returns to the standby state illustrated in
According to this modification described above, the semiconductor chip 5 is pushed up once, and slightly peeled off from the corners of the semiconductor chip 5 during the first phase. Then, the lifting blocks 21, 22, and 23 are sequentially lowered from the outer side. With these lowering operations, the peeling of the adhesive sheet 4 progresses in stages from the outer side toward the inner side of the semiconductor chip 5. Therefore, in addition to the operational effects of the embodiment, the adhesive sheet 4 can be peeled off in a circular shape from the outer side while keeping a push-up distance less than the case of the peeling by sequentially pushing up the adhesive sheet 4 using the lifting blocks toward the inner side.
First Modification
Next, a first modification of the convex portion provided in the lifting block will be described with reference to
The first modification is configured such that a convex portion 32 is formed to protrude in an outermost lifting block 31 of the lifting table 2 in a furrow shape or a line shape having no breaks of a rib shape. A cross section of the convex portion 32 may be formed in a semi-ellipsoidal shape or a semicircular shape illustrated in
According to the first modification, the adhesive sheet 4 is peeled off from the corners of the semiconductor chip 5, and a peeling location moves in a side direction of the semiconductor chip 5. In addition, the adhesive sheet 4 may be peeled off up to a side and not only to the corners of the semiconductor chip 5 when being pushed up the first time. In other words, in the next pushing-up, the adhesive sheet 4 starts to be peeled off from the inner side even at the side of the semiconductor chip 5. Therefore, the convex portion 32 of the lifting block 31 comes in linear or narrow-annular contact with the semiconductor chip 5 through the adhesive sheet 4 and pushes up the chip, so that the stress applied to the semiconductor chip 5 during the first phase can be dispersed. Further, even in the next push-up subsequently performed, the adhesive sheet 4 starts peeling off from the inner side rather than from the side end of the semiconductor chip 5. Therefore, it is possible to more securely avoid breaking and cracking in the side end of the semiconductor chip 5.
Second Modification
Next, a second modification of the convex portion provided in the lifting block 41 will be described with reference to
According to the second modification, the convex portions 42 of the lifting block 41 come in dot-liked contact with the semiconductor chip 5 through the adhesive sheet 4 and push up the chip, so that the stress applied to the semiconductor chip 5 when the adhesive sheet 4 is peeled off can be dispersed compared to the pushing-up of the push-up pin of the related art. In addition, the same effects as those of the first modification can be achieved.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein maybe made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-054311 | Mar 2018 | JP | national |
