JP3918661B2 - Pickup device and pick-up method of chip on wafer sheet - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a chip pickup device and a pickup method on a wafer sheet.
[0002]
[Prior art]
The chip attached by bonding on the wafer sheet is vacuum-sucked at the lower end of the nozzle of the transfer head, and is pushed up from below by the needle of the pepper pot, and peeled off from the wafer sheet by raising the nozzle. Picked up. Then, the transfer head moves above a mounting object such as a circuit board, and a chip is mounted at a predetermined position.
[0003]
7 (a) and 7 (b) are partial cross-sectional views showing the chip pickup operation of the conventional chip pickup device on the wafer sheet, FIG. 8 is a top view of the conventional pepperpot, and FIG. 9 is the conventional chip peeling. FIG. 5 is a relationship diagram of force (chip peeling resistance from a wafer sheet) and nozzle rising distance (peeling time).
[0004]
FIG. 7A shows a state in which the nozzle 9 of the transfer head is lowered and the chip is vacuum-adsorbed to the lower end portion thereof. In the figure, reference numeral 1 denotes a wafer sheet, on which a large number of chips 2 are bonded by bonding (not shown). The upper surface of the covered cylindrical pepper pot 4 is in contact with the lower surface of the wafer sheet 1. Inside the pepper pot 4, a needle 5 for protruding the tip is erected on a lift 6, and the lift 6 is driven by a vertical movement means (not shown) to move up and down. The pepper pot 4 is also moved up and down by a vertical movement means (not shown). The upper surface of the pepper pot 4 is provided with a hole 7 for the needle 5 to move up and down and project and sink, and around the hole 7 is an adsorption for vacuum-sucking the wafer sheet 1 directly under the chip. A hole 8 is opened (see also FIG. 8). The inside of the pepper pot 4 is vacuum-sucked by a vacuum suction means (not shown), whereby the wafer sheet 1 immediately below the chip 2 is vacuum-sucked by the suction holes 8. In FIG. 7, P indicates the vacuum suction pressure.
[0005]
Next, a method for picking up the chip 2 will be described. In FIG. 7A, in a state where the pepper pot 4 is raised and its upper surface is in contact with the lower surface of the wafer sheet 1, the nozzle 9 of the transfer head is lowered (arrow A), and the lower end portion is the pepper pot 4. This is landed on the upper surface of the chip 2 on the hole 7 and vacuum-adsorbed. Around this time, the needle 5 and the lift 6 are raised (arrow B), and the needle 5 protrudes upward from the hole 7.
[0006]
The nozzle 9 that vacuum-sucks the chip 2 starts to rise (arrow C in FIG. 7B), and the chip 2 is peeled off from the wafer sheet 1 while being pushed up by the needle 5 and picked up by the nozzle 9. The nozzle 9 that picks up the chip 2 moves above a mounting target such as a circuit board, and then performs a descending and raising operation to mount the chip 2 at a predetermined position of the mounting target.
[0007]
[Problems to be solved by the invention]
FIG. 9 shows the relationship between the peeling resistance of the chip 2 from the conventional wafer sheet 1 (peeling force generated when the chip 2 is peeled from the wafer sheet 1) and the rising distance of the nozzle (time until complete peeling). . In the figure, t1 is the time until the chip 2 is completely peeled from the wafer sheet 1, and F1 is the maximum value of the peeling force between the chip 2 and the wafer sheet 1 (the peeling resistance of the chip 2 from the wafer sheet 1). . Conventionally, the chip 2 is vacuum-sucked by the nozzle 9, and the nozzle 9 is lifted while the chip 2 is pushed up by the needle 5, so that the chip 2 is completely separated from the wafer sheet 1 at a short time t1 and picked up. The moment of complete peeling is the maximum peeling resistance F1.
[0008]
As described above, conventionally, the chip 2 is instantaneously peeled off from the wafer sheet 1 at a stroke, so that an excessive load is applied to the chip 2 at the time of pick-up, and troubles such as breakage of the chip 2 are likely to occur. In particular, in recent years, the chip 2 tends to be thinned, and an extremely thin chip having a thickness of 100 μm or less has been proposed. Therefore, the above problem cannot be ignored. There is a method of providing a plurality of needles in a pepper pot and pushing up the tip by a plurality of needles. However, even in such a method, the above problems are unavoidable.
[0009]
Accordingly, it is an object of the present invention to provide a chip pickup device and a pickup method for a chip on a wafer sheet that can reduce the load on the chip during pickup and prevent chip breakage.
[0010]
[Means for Solving the Problems]
To this end, the chip pick-up device on the wafer sheet of the present invention is a chip pick-up device that picks up a chip attached to the wafer sheet by an adhesive layer by vacuum suction to the lower end of the nozzle, A pepper pot disposed inside the case, and an opening for vacuum-sucking the wafer sheet on the side of the chip to be picked up on the pepper pot on the upper surface of the case; In addition, the wafer sheet on the lower surface of the chip is vacuum-sucked on the upper surface of the pepper pot, and a hole for projecting and retracting a needle for pushing the chip on the wafer sheet from below is opened, and the inside of the case is sucked a first vacuum suction means, a second vacuum suction means for sucking the inside of the pepper pot vibration to vibrate the pepper pot And means.
[0011]
A chip pickup method on a wafer sheet according to the present invention is a chip pickup method using the chip pickup device on a wafer sheet according to claim 1, wherein the upper surface of the case is brought into contact with the lower surface of the wafer sheet. A step of vacuum-sucking the wafer sheet on the side of the chip on the pepperpot to the opening by driving the first vacuum suction means; and a chip on the pepperpot on the lower end of the chip pickup nozzle A vacuum adsorption step, and driving the vibrating means to vibrate the pepper pot to generate cavitation in a bond for adhering the chip to a wafer sheet. This cavitation generates bubbles in the bond to form the chip and Reducing the sticking power of the wafer sheet and raising the needle to The chip on the sheet is pushed up from below, the nozzle is raised, and the second vacuum suction means is driven to vacuum-suck the wafer sheet on the lower surface of the chip into the hole, and the wafer sheet is chipped by the suction force. and a step from the lower surface of the Ru were detached.
[0012]
In the above configuration, when picking up the chip on the wafer sheet by vacuum suction with the nozzle while raising the chip on the wafer sheet with the needle raised , the pepper pot is vibrated by the vibrating means. Then, cavitation occurs in the bond for adhering the chip to the wafer sheet, and bubbles are generated. Due to the air bubbles, the adhering force of the bond for adhering the chip to the wafer sheet is greatly reduced. Therefore, the chip can be easily detached from the wafer sheet and reliably picked up without imposing an excessive load on the chip.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. FIG. 1 is a sectional view showing the entire structure of a chip pickup device on a wafer sheet in one embodiment of the present invention, and FIG. 2 is a case and a pepper of a chip pickup device on a wafer sheet in one embodiment of the present invention. 3A, 3B, and 3C are partial cross-sectional views showing the chip pickup operation of the chip pickup device on the wafer sheet according to one embodiment of the present invention, and FIG. FIG. 5 is a partial cross-sectional view of a chip pickup device on a wafer sheet when vibration is applied according to an embodiment of the present invention; FIG. FIG. 6 is a plan view, and FIG. 6 is a diagram illustrating a chip peeling force of a chip pickup device on a wafer sheet according to an embodiment of the present invention. Releasing resistance) and a relationship diagram of a rising distance of the nozzle (stripping time). In addition, the same code | symbol is attached | subjected to the same element as a prior art example.
[0014]
First, the overall structure of a chip pickup device on a wafer sheet will be described with reference to FIG. The covered cylindrical case 3 and the covered cylindrical pepper pot 4 inside it are mounted on a U-shaped support portion 11. The support part 11 is supported by the tip of the rod 13 of the cylinder 12 as the first vertical movement means. When the rod 13 protrudes, the case 3 and the pepper pot 4 on the support part 11 move up and down. To do. Although it is desirable that the upper surfaces of the case 3 and the pepper pot 4 be flush with each other, there may be a level difference as long as the vacuum suction of the wafer sheet 1 by the first pump 24 and the second pump 26 described later is not hindered.
[0015]
The elevator 6 on which the needle 5 is erected is supported by the base 14. The support portion 11 is provided with a cylinder 15 as second vertically moving means, and the base portion 14 is supported by the tip end portion of the rod 16. Therefore, when the rod 16 protrudes and retracts, the elevator 6 and the needle 5 move up and down, and the upper end portion of the needle 5 protrudes and retracts from the hole portion 7 opened at the center of the upper surface of the pepper pot 4. A plurality of needles 5 may be provided.
[0016]
A slider 17 is provided on the side of the support portion 11, and the slider 17 is slidably fitted to a vertical linear guide 18. Reference numeral 19 denotes a support for the linear guide 18. Therefore, when the rod 13 of the cylinder 12 protrudes and retracts, the support portion 11 moves vertically up and down along the linear guide 18. At the time of standby, as shown in FIG. 1, the case 3 and the pepper pot 4 are in the lowered position, and their upper surfaces are separated from the wafer sheet 1 above, but when the rod 13 protrudes, they rise and the case 3 and the upper surface of the pepper pot 4 are in contact with the lower surface of the wafer sheet 1 (see FIG. 3A). The various elements such as the cylinder 12 and the support 19 are installed on the movable table 20. The movable table 20 is moved horizontally in the X direction and the Y direction by a moving means (not shown), and the pepper pot 4 is positioned immediately below a predetermined chip 2 to be picked up.
[0017]
The pepper pot 4 is equipped with an ultrasonic (US) vibrator 21 as vibration means, and when this is driven, the pepper pot 4 is ultrasonically vibrated. The vibration means is for generating cavitation in the bond 28 as will be described later. Therefore, the ultrasonic vibrator as in this embodiment is desirable as the vibration means. Further, the vibration means may be provided in the case 3, and the vibration may be transmitted to the pepper pot 4 through the case 3. The installation position can be freely determined. In short, the vibration is applied to the bond 28. To generate cavitation.
[0018]
An opening 22 for vacuum-sucking the wafer sheet 1 is opened on the upper surface of the case 3 (see also FIG. 2). The opening 22 is located on the side of the chip 2 on the hole 7 of the pepper pot 4 to be picked up.
[0019]
In FIG. 1, the inside of the case 3 is vacuum-sucked through a pipe 23 by a first pump 24 that is a first vacuum suction means. Further, the inside of the pepper pot 4 is vacuum-sucked through a pipe 25 to a second pump 26 which is a second vacuum suction means. Reference numeral 27 denotes a seal member that maintains the airtightness between the pepper pot 4 and the lift 6. In FIG. 4, reference numeral 28 denotes a bond for attaching the chip 2 to the wafer sheet 1.
[0020]
The chip pick-up device on the wafer sheet has the above-described configuration. Next, the chip pick-up operation will be described. 3A to 3C show the chip pickup operation in the order of operation. First, the rod 13 of the cylinder 12 is protruded to raise the case 3 and the pepper pot 4, and the upper surfaces thereof are brought into contact with the lower surface of the wafer sheet 1 (see FIG. 3A). Next, the nozzle 9 of the transfer head is lowered (arrow A), the lower end thereof is landed on the upper surface of the chip 2 on the pepper pot 4, and the chip 2 is vacuum-sucked (indicated by a chain line in FIG. 3A). See nozzle 9). Note that the lower surface of the wafer sheet 1 may be brought into contact with the upper surface of the case 3 or the pepper pot 4 by lowering the wafer sheet 1 without raising the case 3 or the pepper pot 4. Is something.
[0021]
At this time, the first pump 24 is driven, and the wafer sheet 1 near the side portion of the chip 2 is vacuum-sucked into the opening 22 (suction pressure is P1). Further, the US vibrator 21 is driven to vibrate the pepper pot 4 by ultrasonic waves (US). Then, many fine bubbles 10 are generated in the bond 28 on the lower surface of the chip 2 by cavitation (see FIGS. 4 and 5), and the bonding force between the chip 2 and the wafer sheet 1 is greatly reduced. Therefore, the peeling resistance of the chip 2 from the wafer sheet 1 is also greatly reduced.
[0022]
Further, when the rod 16 of the cylinder 15 protrudes, the needle 5 that has been retracted to the lower position ascends (the arrow B in FIG. 3B), and protrudes upward from the hole 7 to lower the tip 2 downward. Rush from. Around this time, the nozzle 9 that vacuum-sucks the chip 2 also starts to rise (arrow C). At the same time, the second pump 26 is driven at this time, and the inside of the pepper pot 4 is vacuum-sucked, whereby the wafer sheet 1 is strongly vacuum-sucked in the hole 7 (suction pressure is P2). The operation timing of each element such as the suction timing of the tip 2 by the nozzle 9 and the rising timing of the nozzle 9 and the needle 5 is optimally set according to the type of the tip 2 and the like.
[0023]
Now, as shown in FIG. 3C, the needle 5 and the nozzle 9 continue to rise further (arrows B and C), and the wafer sheet 1 adhered to the lower surface of the chip 2 moves along with the rise of the nozzle 9. Due to the suction pressure P2, it is gradually peeled off from the lower surface of the chip 2 forcibly. 3B and 3C, the wafer sheet 1 indicated by the solid line and the chain line immediately below the chip 2 shows a state of gradually peeling from the lower surface of the chip 2. FIG. In this case, since the fine bubbles 10 are generated by cavitation in the bond 28 on the lower surface of the chip 2 as described above, the bonding force of the bond 28 for bonding the chip 2 to the wafer sheet 1 is significantly reduced. Therefore, the wafer sheet 1 is easily peeled from the lower surface of the chip 2 without applying an excessive load to the chip 2 by the suction pressure P2. 3C, when the wafer sheet 1 is completely peeled off from the lower surface of the chip 2, the nozzle 9 is lifted as it is, and the chip 2 is completely picked up, and a mounting object (not shown) The chip 2 is mounted at a predetermined position of the mounting object. By repeating the above operation, the chips 2 on the wafer sheet 1 are successively picked up by the nozzles 9 and mounted on the mounting object.
[0024]
FIG. 6 shows the relationship between the peeling force (chip peeling resistance) when picking up the chip 2 on the wafer sheet 1 as described above and the rising distance of the nozzle 9 (time until complete peeling). In the figure, F2 is the maximum value of the peeling resistance. Compared with the conventional example shown in FIG. 9, the time t2 until complete peeling is longer than the peeling time t1 of the conventional example, but the maximum value F2 of the peeling resistance is considerably smaller than the peeling resistance F1 of the conventional example. This means that the chip 2 is gradually and softly peeled off from the wafer sheet 1 with a relatively small peeling resistance, and therefore the load that the chip 2 receives during pick-up is small, and therefore the chip is damaged. Hateful.
[0025]
In short, in the conventional example, the chip 2 is peeled off and picked up from the wafer sheet 1 with a strong force in a short time t1, whereas in the present invention, the wafer is slowly taken over a relatively long time t2 with a relatively weak force. The sheet 1 is peeled off and picked up.
[0026]
The pick-up apparatus may be provided with a heating means or a cooling means for heating or cooling the wafer sheet to reduce the bonding force of the bond. In this case, heating and cooling are properly used according to the characteristics of the bond. Moreover, when using a needle, it is desirable that the tip shape of the needle be flat or spherical with a radius of 1 mm or more. As a result, stress concentration on the chip can be avoided and damage to the chip can be reduced. In addition, when the chip can be picked up without using a needle, the needle is not necessarily required, and in this case, there may be no hole for the needle on the upper surface of the pepper pot to project and retract.
[0027]
【The invention's effect】
As described above, in the present invention, when picking up a chip from the wafer sheet while raising the chip on the wafer sheet by raising the needle and picking up the chip from the wafer sheet , the chip is moved to the wafer sheet. The adhesive strength of the bond that adheres to the film is greatly reduced. Therefore, the load applied to the chip during pick-up can be greatly reduced, the chip can be prevented from being damaged, and the chip can be easily picked up. Therefore, it is very useful for picking up a thin chip.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an overall structure of a chip pickup device on a wafer sheet according to an embodiment of the present invention. FIG. 2 shows a case of a chip pickup device on a wafer sheet according to an embodiment of the present invention. FIG. 3A is a partial cross-sectional view showing a chip pickup operation of a chip pickup device on a wafer sheet in one embodiment of the present invention. FIG. 3B is a wafer in one embodiment of the present invention. FIG. 4 is a partial cross-sectional view showing the chip pickup operation of the chip pickup device on the sheet. FIG. 4C is a partial cross-sectional view showing the chip pickup operation of the chip pickup device on the wafer sheet in the embodiment of the present invention. FIG. 5 is a partial cross-sectional view of a chip pickup device on a wafer sheet when vibration is applied according to an embodiment of the present invention. FIG. 6 is a plan view of a chip when a vibration is applied to a chip pickup device on a wafer sheet according to an embodiment of the present invention. FIG. 6 is a chip peeling force of a chip pickup device on a wafer sheet according to an embodiment of the present invention. FIG. 7A is a partial cross-sectional view showing a chip pickup operation of a conventional chip pickup device on a wafer sheet (removal resistance of a chip from a wafer sheet) and nozzle rising distance (removal time). b) Partial sectional view showing chip pick-up operation of a conventional pick-up device for a chip on a wafer sheet. FIG. 8 is a top view of a conventional pepperpot. FIG. 9 is a conventional chip peeling force (peeling resistance from a wafer sheet). ) And nozzle rise distance (peeling time) [Explanation of symbols]
1 Wafer Sheet 2 Chip 3 Case 4 Pepper Pot 5 Needle 7 Hole 9 Nozzle 21 Ultrasonic Vibrator 22 Opening 24 First Pump 26 Second Pump 28 Bond

Claims (2)

A chip pick-up device for picking up a chip stuck by an adhesive layer on a wafer sheet by vacuum suction to the lower end of the nozzle,
A case and a pepper pot disposed inside the case, and an opening for vacuum-sucking a wafer sheet on a side of a chip to be picked up on the pepper pot on the upper surface of the case Further, the upper surface of the pepper pot is vacuum-sucked with the wafer sheet on the lower surface of the chip, and a hole is formed for the needle to push up the chip on the wafer sheet from below, and the inside of the case is opened. Pickup of chips on a wafer sheet , comprising: first vacuum suction means for sucking, second vacuum suction means for sucking the inside of the pepper pot , and vibration means for vibrating the pepper pot apparatus. 2. A chip pick-up method using a chip pick-up device on a wafer sheet according to claim 1, wherein the upper surface of the case is brought into contact with the lower surface of the wafer sheet, and the pepper pot is driven by driving the first vacuum suction means. By vacuum-sucking the wafer sheet on the side of the upper chip to the opening, vacuum-sucking the chip on the pepperpot to the lower end of the chip pickup nozzle, and driving the vibration means Oscillating the pepper pot to generate cavitation in the bond for adhering the chip to the wafer sheet, generating bubbles in the bond by this cavitation to reduce the adhering force between the chip and the wafer sheet, and the needle The nozzle on the wafer sheet is pushed up from below and the nozzle It raised, and said vacuum suction to the underside of the wafer sheet chip to the hole by driving the second vacuum suction means by the suction force to include a step of Ru is peeled wafer sheet from the lower surface of the chip A method for picking up chips on a wafer sheet.

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