JP2015115574A - Wafer conveyance system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer conveyance system capable of simply and surely peeling off a wafer from a placing position, holding the wafer and conveying the wafer without generating failure such as dirt.SOLUTION: A wafer conveyance system for conveying a wafer W vacuum chucked on a chuck table 12 from the chuck table 12 to another place includes: wafer floating means for floating the wafer W from the surface of the chuck table 12 by jetting water from the chuck table 12 side to the wafer W released from vacuum chuck; wafer clamp holding means having a clamp claw portion 21 for holding the wafer W by clamping an edge portion of the floated wafer W; air supply means for jetting air from the chuck table 12 side to the wafer W held by the clamp claw portion 21 to remove water between the wafer W and the chuck table 12; and conveyance means for conveying the wafer W held by the clamp claw portion 21 to a desired position together with the clamp claw portion 21.

Description

  The present invention relates to a wafer transfer system, and more particularly to a wafer transfer system for transferring a wafer toward a required position without causing a defect in the semiconductor device manufacturing process.

  Conventionally, for example, a wafer such as a thin silicon wafer sliced and cut from a silicon ingot or the like is finally commercialized through various processes. In the processing of the wafer, the wafer is usually transferred to various processing steps in order and processed. In addition, there are cases where the wafers are carried over several times, and cases where the wafers are carried one by one. In the present invention, the wafers are carried one by one.

  In the semiconductor device manufacturing process, when the wafers are transferred one by one, it is general that one side of the wafer is vacuum-sucked and held by a suction disk and transferred to the next processing process (for example, Patent Document 1). reference).

  In general, in an electronic device, in order to improve the heat dissipation of the semiconductor chip, and to reduce the thickness of the semiconductor chip as much as possible in a small electronic device using many semiconductor elements, the thickness of the wafer is reduced. , About 100 to 50 μm or less.

  As these wafers become thinner, defects such as chipping and cracking of the wafer are likely to occur in each processing step. As a countermeasure, a member for protecting a device is conventionally protected by a resin-based tape, but it is increasingly protected by a substrate such as glass, silicon, or a resin-based substrate having rigidity.

JP-A-9-64152.

  In the above-described method of transporting one side of the wafer by vacuum suction holding with the suction disk, no gap is generated between the wafer and the suction disk even when the wafer is suctioned and held by the suction disk. For this reason, when it is necessary to perform double-sided cleaning of the wafer during the transfer of the wafer, it is necessary to switch to a method of clamping the outer peripheral edge of the wafer. In this case, it is necessary to prepare a plurality of pins such as a cylinder or the like, and to make the pins come into contact with the outer peripheral surface of the wafer and perform clamping, and the structure is complicated.

  For example, in the process of grinding the surface of the wafer, water is used to grind the wafer. For this reason, even after the wafer is ground, even if the vacuum state of the chuck table that has vacuum-adsorbed the wafer is released, the wafer cannot be easily peeled off by the tension of the water film between the wafer and the chuck.

  Therefore, in order to solve these problems, when peeling the wafer, the wafer is usually sucked with a suction disk, the vacuum chuck of the chuck table is stopped, and then air is blown from the lower side of the chuck table toward the wafer to release it. After that, it is transferred to the required position.

  Furthermore, if the surface of the wafer is sucked many times by the suction disk, dirt is accumulated on the suction surface, and the dirt is transferred to the wafer, resulting in problems in subsequent wafer processing steps.

  Therefore, the wafer can be easily and surely peeled off from the mounting position, and the peeled wafer can be securely held and transported to the required position so as not to cause problems such as dirt. The technical problem which should be solved in order to provide the above described wafer conveyance system arises, and this invention aims at solving this problem.

  The present invention has been proposed in order to achieve the above-mentioned object, and the invention according to claim 1 transfers a substantially disk-shaped wafer vacuum-chucked on the chuck table from the chuck table to another place. In the wafer transfer system, the wafer floating means for floating the wafer from the chuck table by jetting water from the chuck table side to the wafer from which the vacuum chuck has been released, and the wafer floating on the check table Wafer clamp holding means having a clamp claw for clamping the edge portion of the wafer and holding the wafer, and air is jetted from the chuck table side to the wafer held by the clamp claw An air supply hand for removing the water between the wafer and the chuck table If, to provide a wafer transport system comprising a transport means for transporting the wafer held by the clamp claw portion to a required position together with the clamping claw portion.

  According to this system configuration, the vacuum chuck of the chuck table that holds the wafer by vacuum suction is stopped, and then the clamp claw portion of the wafer clamp holding means is disposed at a position where the edge portion of the wafer can be clamped. Subsequently, water is jetted from the chuck table side toward the wafer by the wafer floating means, and the wafer is floated on the chuck table. When the wafer floats from the chuck table, the edge portion of the wafer is clamped by the clamp claw portion of the wafer clamp holding means. After clamping, air is blown from the chuck table side toward the wafer by the air supply means to remove water between the wafer and the chuck table and eliminate surface tension therebetween. Thus, the wafer can be easily peeled off from the chuck table with a small force by the wafer clamp holding means that clamps the edge portion of the wafer with the clamp claws. Further, the peeled wafer is stably held by the clamp claws, and can be transferred to a required position together with the wafer clamp holding means by the transfer means.

  According to a second aspect of the present invention, in the configuration according to the first aspect, the clamp claws are provided on the outer periphery of the wafer at a predetermined interval in the outer peripheral direction. A lower claw that is movable from the outside of the area where the wafer is arranged to an inside area, and an upper claw that is always set inside the area where the wafer is arranged, and the upper claw Provided is a wafer transfer system formed as an inclined surface in which a surface facing the wafer is inclined so as to rise from the outside toward the inside.

  According to this system configuration, when the claw portion of the wafer clamp holding means is arranged at a position where the edge portion of the wafer can be clamped, and then the wafer is floated by jetting water by the wafer floating means, In contact with the inclined surface of the upper claw in each clamp claw portion provided at a required interval. In addition, since each inclined surface is inclined so as to rise from the outside toward the inside, the wafer that is in contact with the inclined surface of the upper claw in each clamp claw portion is moved and positioned by the inclined surface toward the center side. . Thereby, it is possible to always clamp the wafer at the same position of the clamp claw.

According to the present invention, when the wafer is peeled off from the chuck table, the wafer is not lifted off by the clamping claw, but is restrained between the wafer and the chuck table by floating with water and removing surface tension with air. Since the wafer can be peeled off with a small force in a state in which the force is removed, it is possible to eliminate a problem that is given to the wafer at the time of peeling. In addition, the clamping claw part is clamped only at the edge from peeling to transfer to the required position, and can be transferred without contacting the wafer surface at all. Can do. Therefore, in this wafer transfer system, the wafer can be easily and reliably peeled off from the chuck table as the mounting position, and the peeled wafer can be securely held and transferred to the required position. it can.
The present invention is applied to a wafer having a total thickness of 400 μm or more because it is difficult to apply to a wafer and its device protection substrate having a thin total thickness due to the nature of the mechanism.

The block diagram which shows the structure of the wafer conveyance system to which this invention is applied. The perspective view which shows schematic arrangement structure of a wafer check table, a wafer clamp holding means, and a conveyance means. FIG. 3 is a schematic front view of FIG. 2. The figure explaining the clamp nail | claw part of a wafer clamp holding means. The figure explaining an example of the process sequence in the wafer conveyance system which concerns on this invention.

  In the present invention, the wafer can be easily and surely peeled off from the mounting position, and the peeled wafer is securely held, and the required position is maintained so as not to cause problems such as dirt. In order to achieve the object of providing a wafer transfer system capable of being transferred, a wafer transfer system for transferring a substantially disk-shaped wafer vacuum chucked on a chuck table from the chuck table to another location, Water is ejected from the chuck table side to the wafer on which the vacuum chuck has been released to float the wafer from the chuck table, and the edge portion of the wafer that has floated on the check table is clamped. Wafer clamp having a clamping claw for holding the wafer Holding means; air supply means for ejecting air from the chuck table side to the wafer held by the clamp claws to remove the water between the wafer and the chuck table; and the clamp And a transfer means for transferring the wafer held by the claw portion to a required position together with the clamp claw portion.

  Hereinafter, specific examples of the wafer transfer system according to the embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration example of a wafer transfer system to which the present invention is applied. This system includes a control unit 11 having a central processing function for controlling the entire system, a chuck table 12 for processing the wafer W, and the like.

  The control unit 11 is, for example, a computer. The controller 11 is connected to the control unit 11 in a controllable manner: a wafer vacuum suction means 13, a wafer floating means 14, a wafer clamp holding means 15, an air supply means 16, and a transfer means 17.

  In the present embodiment, the chuck table 12 is used for mounting a thin disk-shaped wafer W provided with electronic devices as shown in FIG. On the chuck table 12, water is ejected from the side of the chuck table 12 to the vacuum suction means 13 for holding the wafer W placed thereon by vacuum chucking, and the lower surface of the wafer W from which the vacuum chuck is unwound. The wafer floating means 14 for floating the wafer W from the chuck table 12 and the air is blown from the chuck table 12 side to the lower surface of the wafer W from which the vacuum chuck is unwound, and exists between the wafer W and the chuck table 12. The air supply means 16 for removing the water to be connected is connected. Therefore, on the wafer mounting surface 12 a of the chuck table 12, although not shown, an air suction port for vacuum chucking the lower surface of the wafer W, a water jet port for ejecting water toward the lower surface of the wafer W, and a lower surface of the wafer W Air outlets for ejecting air toward each other are provided. In some cases, the air inlet, the water outlet, and the air outlet are installed so as to be shared with each other.

  The wafer levitation means 14 has a water ejection device (water blow mechanism) (not shown) and a water supply pipe (not shown) connected to the water ejection port of the chuck table 12. Then, water whose pressure is adjusted by the water jetting device under the control of the control unit 11 is jetted (water blown) from the water jetting port toward the lower surface of the wafer W, whereby the entire wafer W is placed on the chuck table 12. It is possible to float from the surface 12a. The water pressure here is, for example, about 0.2 to 0.3 Mp so that a gap can be formed at which a lower claw 22a of a clamp claw portion 21 described later in the wafer clamp holding means 15 can be inserted into the lower surface side of the wafer W. Done.

  The air supply means 16 has an air compressor (air blow mechanism) (not shown) and an air supply pipe (not shown) connected to an air outlet of the chuck table 12. Then, the air pressure-adjusted by the air compressor under the control of the control unit 11 is ejected (air blow) from the water ejection port toward the lower surface of the wafer W, so that the space between the wafer W and the mounting surface 12a of the chuck table 12 is increased. The surface tension acting between the wafer W and the wafer mounting surface can be eliminated by removing the water present in the wafer. The air pressure here is about 20 to 30 Kpa.

  The conveying means 17 and the wafer clamp holding means 15 are schematically shown together with the chuck table 12 and the wafer W in FIGS. In this embodiment, the chuck table 12 is formed in a disk shape, and the mounting surface 12a is also formed in a disk shape.

  One end side (base end side) 17a of the transfer means 17 is fixed to, for example, a robot arm or the like, and the wafer clamp holding means 15 is attached to the other end side (free front end side 17b). The transfer means 17 is movable together with the wafer clamp means 15 from the operation position shown in FIGS. 2 and 3 to a required position (not shown) in conjunction with the movement of the robot arm, for example. That is, the wafer W before the processing is moved from the previous process position onto the chuck table 12 by the movement with the wafer clamp means 15, and the wafer W after the processing is provided at the required position from the chuck table 12. It can be moved to the post-process position.

  As shown in FIGS. 2 and 3, the wafer clamp holding means 15 is extended in two directions from a main body portion 15a rotatably attached to the lower surface side of the transfer means 17 on the free tip 17b side. A claw first arm 18a attached horizontally, a pair of claw second arms 18b horizontally attached to intersect with the tip of the first arm 18a, and a claw first arm 18a. A first arm 19a for height adjustment that is horizontally mounted in a state extending in two directions from the main body portion 15a intersecting with one arm 18a, and intersecting at a right angle with the tip of the first arm 19a. And a pair of height adjusting second arms 19b attached horizontally.

A clamp claw portion 21 that protrudes downward is attached to each end of the pair of second arms 18b. These four clamp claws 21 are shifted from the positioning pins 20 in the outer peripheral direction by a required amount, respectively, and just outside a later-described wafer placement area SW (see FIG. 4) of the wafer placement surface 12a of the chuck table 12. Correspondingly provided.

  Further, as shown in FIG. 4, each clamp claw portion 21 is on a wafer placement 12a in the chuck table 12 and an area SW where the wafer W is arranged (hereinafter referred to as “wafer arrangement area SW”). The lower claw 22a that can move from the outside to the inside area, the upper claw 22b that is always arranged inside the wafer arrangement area SW at the time of setting, and the lower claw 22a and the upper claw 22b are connected. And a vertical surface portion 22c. Then, the lower claw portion 22a, the upper claw portion 22b, and the vertical surface portion 22c are arranged toward the inside of the wafer clamp holding means 15. The lower claw 22a is formed as an inclined surface so that the surface facing the wafer W rises from the inside toward the outside, and the upper claw 22b has a surface facing the wafer W from the inside. It is formed as an inclined surface that is inclined so as to rise toward the outside.

  The clamp claws 21 are moved from the outside of the wafer placement area SW to the inside area by controlling the movement of the first arm 18a for claw (position indicated by a solid line in FIG. 4). And the lower claw 22a can be selectively switched to a non-clamping position (a position indicated by a two-dot chain line in FIG. 4) where the lower claw 22a has moved from the inside to the outside of the wafer arrangement area SW. .

  FIG. 5 is a diagram illustrating an example of a processing procedure of the wafer transfer system in the present embodiment, which is processed according to the program set in the control unit 11. Hereinafter, the operation of the wafer transfer system in the present embodiment will be described in the order of procedures (1) to (6) with reference to FIG.

  Procedure (1): When the processing of the wafer W set on the wafer placement surface 12a of the chuck table 12 is completed, the control unit 11 stops the vacuum chuck by the wafer vacuum suction means 13.

Step (2): Next, the control unit 11 places the wafer clamping means 15 substantially in contact with the wafer mounting surface 12a of the chuck table 12 in a state where the clamp claw portion 21 is disposed at the non-clamping position, that is, the wafer. When W floats from the wafer placement surface 12a, the lower claw 22 of the clamp claw portion 21 is lowered to a position where it can enter the lower surface of the wafer W. As shown by a two-dot chain line in FIG. 2, the lower claws 22a are arranged outside the wafer arrangement area SW, and the upper claws 22b are arranged in the wafer arrangement area SW. Set in the state of being placed inside.

  Procedure (3): Next, the controller 11 operates the wafer levitation means 14 to eject water whose pressure has been adjusted by the water jetting device from the water jetting port toward the lower surface of the wafer W. Is lifted from the mounting surface 12 a of the chuck table 12. At this time, since the upper claw 22b of each clamp claw portion 21 protrudes into the wafer placement region SW, the wafer W lifted from the placement surface 12a abuts on the inclined surface of the upper claw 22b, and the inclined surface Moved to the center side.

Procedure (4): Subsequently, the control unit 11 operates the wafer clamping means 15 to move the clamp claw portion 21 from the non-clamp position to the clamp position via the first arm 18a for claw. In this case, since the wafer W is levitated from the mounting surface 12a of the chuck table 12 by the wafer levitating means 14, the lower claws 22a of the clamp claws 21 are located on the wafer W.
It moves in a state of smoothly entering the lower surface of the. Then, the upper and lower claws 22a and 22b of the clamp claw portion 21 are restricted from moving in the upward direction, and the vertical surface portion 22c is brought into contact with the peripheral surface of the wafer W. The peripheral edge, that is, the edge portion is clamped. Further, when the wafer W is clamped by the clamp claw portion 21, the ejection of water by the wafer floating means 14 is stopped.

  Step (5): Subsequently, the control unit 11 operates the air supply means 16 while holding the clamp claw portion 21 at the clamp position, and the air pressure-adjusted by the air compressor is sent from the air jet port to the wafer W. It spouts toward the bottom. Then, the air ejection removes water existing between the wafer W and the wafer placement surface 12a of the chuck table 12, thereby eliminating the surface tension between the wafer W and the wafer placement surface 12a.

  Step (6): Next, the control unit 11 operates the transfer unit 17 while holding the clamp claw portion 21 in the clamp position, lifts the wafer clamp holding unit 15 together with the wafer W, and moves the wafer W to the chuck table 12. Remove from. Subsequently, the transfer means 17 is rotated horizontally with the base end side 17b as a fulcrum, and the wafer W is transferred to the next process. Therefore, the peeling of the wafer W here is performed by removing the water between the wafer W and the wafer mounting surface 12a of the chuck table 12 in the procedure (5) to eliminate the surface tension. Thus, the wafer W can be easily peeled off from the chuck table 12. Thereby, the trouble given to the wafer W at the time of peeling can be eliminated.

  As described above, according to the wafer transfer system of the present embodiment, when the wafer W is clamped from the chuck table 12, the wafer floating means 14 floats with water, and the air supply means 16 removes surface tension with air. Thus, since the restraining force between the wafer W and the chuck table 12 can be removed and the wafer W can be peeled off with a small force, it is possible to eliminate the problem that is given to the wafer W at the time of peeling. In addition, the clamp claw 21 clamps the edge portion of the wafer W and does not contact the surface on which the circuit or the like is formed from peeling to transporting to a required position. Etc. can be eliminated.

  Further, when the clamp claw portion 21 of the wafer clamp holding means 15 is disposed at a position where the edge portion of the wafer W can be clamped, and then the water is ejected by the wafer floating means 14 to float the wafer W from the wafer mounting surface 12a. The edge portions of the floated wafer W are in contact with the inclined surfaces of the upper claws 22b in the respective clamp claws 21 provided at a predetermined interval in the outer circumferential direction, and the wafers W are in contact with the inclined surfaces of the upper claws 22b. Since it is positioned by moving to the center side by the inclined surface, it can always be clamped at the same position.

  It should be noted that the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones. For example, in the above-described embodiment, a structure in which four clamp claws 21 are provided is disclosed.

  The present invention can be applied to the case of transferring a circuit board in addition to transferring the wafer W.

DESCRIPTION OF SYMBOLS 11 Control part 12 Chuck table 12a Wafer mounting surface 13 Wafer vacuum suction means 14 Wafer levitation means 15 Wafer clamp holding means 15a Main body part 16 Air supply means 17 Conveyance means 17a One end side (base end side)
17b The other end side (free tip side)
18a Claw first arm 18b Claw second arm 19a Height adjustment first arm 19b Height adjustment second arm 20 Positioning pin 21 Clamp claw portion 22a Lower claw 22b Upper claw 22c Vertical surface portion SW Wafer placement area

Claims (2)

In a wafer transfer system for transferring a substantially disc-shaped wafer vacuum chucked on a chuck table from the chuck table to another location,
Wafer levitation means for ejecting water from the chuck table side to the wafer on which the vacuum chuck has been released to float the wafer from the chuck table;
Wafer clamp holding means having a clamp claw for clamping the edge portion of the wafer levitated on the check table and holding the wafer;
Air supply means for ejecting air from the chuck table side to the wafer held by the clamp claws to remove the water between the wafer and the chuck table;
Transport means for transporting the wafer held by the clamp claw portion to a required position together with the clamp claw portion;
A wafer transfer system comprising: A plurality of the clamp claws are provided on the outer periphery of the wafer at a predetermined interval in the outer peripheral direction, and each clamp claw moves from the outer area to the inner area of the wafer. A lower claw that is possible, and an upper claw that is always set inside the area where the wafer is located, and the surface of the upper claw that faces the wafer rises from the outside toward the inside. It is formed as an inclined surface that is inclined,
The wafer transfer system according to claim 1.

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