Semiconductor-chip exfoliating device and semiconductor-device manufacturing method

A semiconductor-chip exfoliating device for exfoliating a semiconductor chip 1 from an adhesive sheet 6 is provided. The device includes a backup holder 28 for holding the adhesive sheet 6 so that semiconductor chips 1 turn upward, a pair of needle pins arranged on a backside of the holder 28 to lift off the adhesive sheet 6 from the holder 28 through through-holes 31a, 31b in the holder 28 and a sliding unit 33 arranged on the backside of the holder 28 to slide one needle pin 30b in a direction to depart from the other needle pin 30a. By the sliding unit 33, the interval between the needle pins 30a, 30b can be changed so as to cope with a variation of semiconductor chips 1, 1A.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to device and method for manufacturing semiconductor devices. More particularly, the invention relates to semiconductor-chip exfoliating device and method that are constructed so as to lift off an adhesive sheet having a semiconductor chip by means of lift-off pins whereby one semiconductor chip can be exfoliated from the adhesive sheet.

2. Description of the Related Art

Japanese Patent Publication Laid-open (heisei) No. 10-112465 discloses a prior art apparatus for manufacturing semiconductor devices. In the apparatus, a semiconductor chip adhered to an adhesive film (dicing sheet) is lifted up by lift-off pins (needle pins) to thereby exfoliate the semiconductor chip from the adhesive sheet. The so-exfoliated semiconductor chip is used to manufacture a semiconductor device.

In the above-mentioned apparatus, a single semiconductor chip is lifted up by using a plurality of needle pins.

SUMMARY OF THE INVENTION

However, the above-mentioned manufacturing apparatus for semiconductor devices is not thoughtful of the following points.

In exfoliating one semiconductor chip from the adhesive sheet, it is preferable to allow the lift-off pin to lift off chip's margins on both sides of the semiconductor chip as a target. The knocking-up of the lift-off pins against chip's margins on both sides of the chip allows the semiconductor to be exfoliated from the adhesive sheet with ease, also allowing the exfoliated chip to be broken with difficulty.

In the above-mentioned apparatus, however, the interval between the lift-off pins is constant in spite of a variety of semiconductor chips in size to be adhered to the adhesive sheet. Therefore, if it is required to exfoliate one of semiconductor chips from the adhesive sheet, the semiconductor chips each having a different size from that of the normal semiconductor chip, it is necessary to replace an original lift-off unit for the normal semiconductor chip to another lift-off unit where the interval between the lift-off pins is changed for such a different semiconductor chip.

It is apt to take time and work in exchanging one lift-off unit to another one in the manufacturing process, causing the productivity of the semiconductor devices to be reduced.

Under such a situation, an object of the present invention is to provide a semiconductor-chip exfoliating device capable of making it ease to exfoliate a semiconductor chip from an adhesive sheet throughout semiconductor chips of difference sizes. Another object of the present invention is to provide a semiconductor-chip exfoliating method of exfoliating one semiconductor chip from the adhesive sheet through the use of the above semiconductor-chip exfoliating device.

In order to attain the former object, according to the present invention, there is provided a semiconductor-chip exfoliating device for exfoliating a semiconductor chip from an adhesive sheet to which a plurality of semiconductor chips are adhered, comprising: a holder for holding the adhesive sheet so that the semiconductor chips turn upward; at least two through-holes formed in the holder; at least two lift-off pins arranged on a backside of the holder to lift off the adhesive sheet from the holder through the through-holes; and a sliding unit arranged on the backside of the holder to slide at least one lift-off pin in a direction to depart from the other lift-off pin to thereby change an interval between the lift-off pins.

In order to attain the latter object, according to the present invention, there is also provided a semiconductor-device manufacturing method, comprising the steps of: preparing a semiconductor-chip exfoliating device including a holder for holding the adhesive sheet so that a plurality of semiconductor chips turn upward, at least two through-holes formed in the holder, at least two lift-off pins arranged on a backside of the holder to lift off the adhesive sheet from the holder through the through-holes, and a sliding unit arranged on the backside of the holder to slide at least one lift-off pin in a direction to depart from the other lift-off pin to thereby change an interval between the lift-off pins; allowing the holder to hold the adhesive sheet so that the semiconductor chips turn upward; and raising the lift-off pins to lift off the adhesive sheet from the holder, whereby one semiconductor chip can be exfoliated from the adhesive sheet.

With the above semiconductor-chip exfoliating device and semiconductor-device manufacturing method, by adjusting the interval between the lift-off pins corresponding to the size of a target semiconductor chip, it is possible to make the semiconductor chip easy to be exfoliated from the adhesive sheet, although there is a difference in size of the semiconductor chips adhered to the adhesive sheet.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be described with reference to attached drawings.

As shown inFIG. 1, a manufacturing apparatus for semiconductor devices includes a wafer stage2for mounting a semiconductor wafer (not shown) thereon. The wafer stage2comprises a base3, a first table4and a second table5both mounted on the base3. The second table5carries an adhesive sheet6to which a plurality of semiconductor chips1are adhered. The first table4is movable in both directions of X-axis and Y-axis. While, the second table5is rotatable about Z-axis in the direction of θ. For convenience of explanation, the first table4and the second table5will be referred to as “XY-axes table4” and “θ table5” respectively, hereinafter. The semiconductor chips1are produced by cutting off a piece of semiconductor wafer, which is adhered to the adhesive sheet (so-called “dicing sheet”)6, by means of a dicing saw (not shown) vertically and horizontally. After cutting off the wafer, the adhesive sheet6is expanded so as to produce a gap between the adjoining semiconductor chips1.

A pickup reversing unit7is arranged over the θ table5. The pickup reversing unit7includes a guide8, a third table9slidable along the guide8in the direction of Z-axis, an attachment10fixed to the third table9and an L-shaped pickup reversing tool11rotatably mounted on an end of the attachment10. For convenience of explanation, the third table9will be referred to as “Z-axis table9” hereinafter. The pickup reversing tool11is arranged so as to be rotatable about a joint point to the attachment10within an angular range of 180 degrees between one illustrated position with solid lines and another illustrated position with broken lines. The pickup reversing tool11is also provided, at a tip thereof, with a pickup head12for carrying a semiconductor chip1in absorption.

Over the pickup reversing tool11, there are a first camera13and a second camera14. In operation, the first camera13is adapted so as to take a picture of the semiconductor chip1being mounted on the θ table5. Based on imaging signals from the first camera13, the semiconductor chip1carried in absorption by the pickup head12is identified. In detail, the positioning of the θ-table5in the directions of X-axis, Y-axis and θ is determined base on the imaging signals outputted from the first camera13. On the other hand, the second camera14is adapted so as to take a picture of the semiconductor chip1being carried in absorption by the pickup head12. The shooting of the second camera14against the semiconductor chip1is carried out when the pickup reversing tool11is rotated and consequently located in a position shown with solid lines ofFIG. 1. Based on imaging signals of the second camera14, a bonding head15is driven to allow a bonding tool16to receive a semiconductor chip1from the pickup head12. The so-delivered semiconductor chip1is picturized by a third camera17.

The bonding head15includes a base18. A first table19is attached to the base18so as to be slidable in the direction of X-axis. A second table20is attached to the first table19so as to be slidable in the direction of Y-axis. Further, a third table21is attached to the second table20so as to be slidable in the direction of Z-axis. For convenience of explanation, the first table19, the second table20and the third table21will be referred to as “X-axis table19”, “Y-axis table20” and “Z-axis table21”, respectively. A fourth table22is attached to the Z-table21so as to be rotatable about Z-axis in the direction of θ. The fourth table22will be also referred to “θ table22” after. The θ table22is provided with the above bonding tool16. Thus, the bonding tool22is movable in the directions of X-axis, Y-axis Z-axis and θ, respectively.

Below the bonding head15, there is a bonding stage23which is movable in the direction of X-axis. A substrate24is mounted on the bonding stage23. The semiconductor chip1delivered to the bonding tool16is installed on the substrate24.

A guide25is arranged above the bonding stage23. A table26is attached to the guide25so as to be slidable in the direction of Y-axis. A fourth camera27is attached to the so-called “Y-axis” table26so as to be movable in the direction of Z-axis. The fourth camera27is adapted so as to take a picture of a semiconductor chip1mounted on the substrate24. Thus, the fourth camera27is movable in the directions of X-axis, Y-axis and Z-axis relatively to the substrate24on the bonding stage23.

FIG. 2shows a semiconductor-chip exfoliating device forming the semiconductor-device manufacturing device. Inside the θ table5, as shown inFIGS. 2 and 3, there are a backup holder28(as a holder of the invention) in the form of a hollow cylinder, a lift-off unit29accommodated in the backup holder28and a decompressor (not shown) for reducing pressure in the backup holder28.

The backup holder28is adapted so as to be slidable in the θ table5in both directions of X-axis and Y-axis, together with the lift-off unit29accommodated in the holder28. The backup holder28has a top wall28aopposed to the lower surface of the adhesive sheet6through a slight gap. In the backup holder28, the top wall28ais formed with through-holes31a,31bthrough which later-mentioned needle pins30a,30b(as lift-off pins of the invention) move in and out. The through-hole31ais shaped to be a circular hole, while the through-hole31bis shaped to be an elongated hole. The through-hole31ais positioned to be an extension of the through-hole31bin the longitudinal direction.

In operation, the lift-off unit29lifts off a semiconductor chip1by the needle pins30a,30bto exfoliate the chip1from the adhesive sheet6. The lift-off unit19includes the above needle pins30a,30b, shuttle mechanisms32a,32band a sliding unit33.

The needle pins30a,30bhave respective one ends opposed to the through-holes31a,31band the other ends abutting on eccentric cams33a,33b, respectively. When the needle pins30a,30breciprocate in their axial direction to allow the respective ends to project from the through-holes31a,31b, one semiconductor chip1is lifted up together with the adhesive sheet6.

The shuttle mechanisms32a,32bare provided to reciprocate the needle pins30a,30bin the axial direction and comprise the above cams33a,33babutting on the other ends of the needles pins30a,30band motors34a,34bconnected to the cams33a,33b, respectively. The cam33ais formed with a width “a” smaller than a width “b” of the cam33b. When the motors34a,34bare driven to rotate the cams33a,33b, the needle pins30a,30breciprocate in the axial direction. Not-shown urging means, such as springs, are attached to the needle pins30a,30b. The urging means urge the pins30a,30bin the direction to abut their other ends on the cams33a,33b, respectively.

The lift-off timing of the needle pins30a,30bis switchable between an operation mode of the same timing and another operation mode of different timings. When the former mode of the same timing is selected, the motors34a,34bare driven at the same timing, so that the needle pins30a,30bare lifted up at the same timing. On the other hand, when the later mode of the different timings is selected, the motors34a,34bare driven at the different timing, so that the needle pins30a,30bare lifted up one by one with a time difference.

The sliding unit33is constructed so as to slide the needle pin30bin the direction to change an interval between the needle pin30aand the needle pin30b. The sliding unit33includes a slide shaft35perpendicular to the needle pins30a,30b, a female screw part36fixed to the slide shaft35, a ball screw shaft37screw-engaged with the female screw part36and a motor38connected to the ball screw shaft37.

The slide shaft35is formed with through-holes39a,39binto which the needle pins30a,30bare inserted. The through-hole39afor the needle pin30ais shaped to be an elongated hole. The through-hole39bfor the needle pin30bis shaped to be a circular hole having an inner diameter somewhat larger than the outer diameter of the needle pin30b. The through-hole39bis positioned to be an extension of the through-hole39ain the longitudinal direction.

The operation of exfoliating the semiconductor chip1from the adhesive sheet6with use of the lift-off unit29will be described below. When a semiconductor chip1to be exfoliated is determined based on the shooting result by the first camera13, the backup holder28is moved to a position beneath the semiconductor chip1on determination.

After the backup holder28reaches the position beneath the target semiconductor chip1, the above decompressor is started to drive. Consequently, air inside the backup holder28is sucked in the decompressor and simultaneously, outside air is also sucked in the backup holder28through the through-holes31a,31b. With this air suction into the backup holder28via the through-holes31a,31b, the adhesive sheet6is absorbed onto the top wall28aof the back up holder28.

After a predetermined time has passed since the decompression was started by the decompressor, the motors34a,34bare driven to rotate the cams33a,33b, causing the needle pins30a,30bto be pushed up, as shown inFIG. 4. The tips of the needle pins30a,30bpushed up by the cams33a,33brise through the through-holes31a,31band lift off one semiconductor chip1while being adhered to the adhesive sheet6. Then, the adhesive sheet6just under the so-pushed semiconductor chip1is partially expanded to weaken the bonding property between the semiconductor chip1and the adhesive sheet6, making the chip1easy to be exfoliated from the adhesive sheet6.

Corresponding to the size of the semiconductor chip1, the interval between the needle pins30a,30bis established so that they can lift off chip's margins on both sides of the semiconductor chip1.

Further, in the timing synchronous with the lifting operation of the needle pins30a,30b, the pickup head12is moved to a position above the semiconductor chip1and successively, it is carried in absorption by the pickup head12.

The semiconductor chip1carried in absorption by the pickup head12is delivered to the bonding tool16of the bonding head15and subsequently installed on the substrate24mounted on the bonding stage23.

FIGS. 5 and 6are views explaining the operation of the lift-off unit29directed to semiconductor chips1A adhered to the adhesive sheet6, each of which is larger than the afore-mentioned semiconductor chip1. In case of such a large-sized semiconductor chip, the interval between the needle pins30a,30bis also increased correspondingly.

When it is required to increase the interval between the needle pins30a,30b, the sliding unit33is operated to slide only the needle pin30bon the cam33bin a direction to depart from the other needle pin30a. For this purpose, the motor38is driven to slide the slide shaft35to the right in the figures through the use of screw-engagement of the ball screw shaft37with the female screw part36. With the sliding of the slide shaft35to the right, the needle pin30binserted into the through-hole39bhaving the inner diameter somewhat larger than the outer diameter of the pin30bis slid on the cam33bto the right together with the slide shaft35. While, the other needle pin30ainserted into the through-hole39ain the form of an elongated hole does not slide to the right due to no interference with an inner sidewall of the through-hole39ain spite of the sliding of the needle pin30b. In this way, the interval between the needle pins30a,30bis increased.

A final interval between the needle pins30a,30bresulting from the rightward sliding of the needle pin30bis determined corresponding to the size of the semiconductor chip1A to be lifted off by the needles30a,30b. The final interval is established so that the needle pins30a,30bcan lift off chip's margins on both sides of the semiconductor chip1A.

Note, the stable needle pin30ais maintained so that its tip opposes the through-hole31a, while the movable needle pin30bis maintained so that its tip opposes the through-hole31bin form of an elongated hole.

As mentioned before, the cam33bis formed with a width “b” larger than that of the cam33a. The formation of the cam33bis provided for the purpose of maintaining the abutment of the cam33bon the other end of the needle pin30bin spite of its sliding.

As shown inFIGS. 5 and 6, after adjusting the interval between the needle pins30a,30bcorresponding to the size of the semiconductor chip1A, the backup holder28is moved to a position beneath the semiconductor chip1A to be exfoliated from the adhesive sheet6, similarly to the above case of exfoliating the semiconductor chip1and simultaneously, the decompressor is driven to allow the backup holder28to absorb the adhesive sheet6on the top wall28a. Next, the motors34a,34bare driven to rotate the cams33a,33b, causing the needle pins30a,30bto be pushed up. The tips of the needle pins30a,30bpushed up by the cams33a,33brise through the through-holes31a,31bto lift off the semiconductor chip1A while being adhered to the adhesive sheet6.

In this way, for the semiconductor chips of different sizes, it is possible to make the interval of the needle pins30a,30baddress a target semiconductor chip, allowing an abutment of the pins30a,30bon the chip's margins on both sides of the chip. Thus, it is possible to exfoliate the semiconductor chips1,1A of difference sizes from the adhesive sheet6appropriately.

As for the lift-off timing of the needle pins30a,30b, there may be optionally selected either the operation mode of the same timing or the operation mode of the different timing, as similar to the above-mentioned case. When selecting the former mode of the same timing, the motors34a,34bare driven at the same timing, so that the needle pins30a,30bare lifted up at the same timing. On the other hand, when selecting the later mode of the different timing, the motors34a,34bare driven at the different timings, so that the needle pins30a,30bare lifted up one by one with a time difference. For instance, as shown inFIG. 7A, only the needle pin30ais lifted up at first. Then, after the lapse of a predetermined time since the rising of the pin30a, the remained needle pin30bis lifted up as shown inFIG. 7B.

As shown inFIGS. 7A and 7B, by lifting up the needle pins30a,30bwith a time difference therebetween, the adhesive sheet6beneath the semiconductor chip1A is drawn in twice of one expansion by the needle pin30aand another expansion by the needle pin30b, so that the adhesive joint between the semiconductor chip1A and the adhesive sheet6can be further weakened in comparison with a single expansion of the same timing, making the chip1A easier to be exfoliated from the adhesive sheet6.

The semiconductor chip1A lifted off by the needle pins30a,30bis carried in absorption by the pickup head12and further delivered to the bonding tool16of the bonding head15. Finally, the so-delivered semiconductor chip1A is installed on the substrate24mounted on the bonding stage23.

In this way, according to the present invention, by adjusting the interval between the lift-off pins corresponding to the size of a target semiconductor chip, it is possible to make the semiconductor chip easy to be exfoliated from the adhesive sheet despite that there is a difference in size of the semiconductor chips adhered to the adhesive sheet.

In a modification, the number of lift-off pin may be increased to lift off one semiconductor chip in more stable condition, although the illustrated embodiment adopts a pair of lift-off pins.

Additionally, the lift-off pins may be moved up and down by the other appropriate means, such as linear actuators, although they are driven due to their abutment on the eccentric cams33a,33brotated by the motors34a,34bin the illustrated embodiment,

Although the present invention has been described above by reference to one embodiment of the invention, this invention is not limited to this and modifications will occur to those skilled in the art, in light of the teachings. The scope of the invention is defined with reference to the following claims.

This application is based upon the Japanese Patent Applications No. 2007-067974, filed on Mar. 16, 2007, the entire content of which is incorporated by reference herein.