JP2018142615A - Wafer carrying/holding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer carrying/holding device that is configured so that loads can be evenly applied to a wafer when pressing the wafer, even if the wafer is largely warped, to prevent the wafer from being damaged and so that the wafer can be surely suctioned and held with a chuck table.SOLUTION: The wafer carrying/holding device comprises: a holding pad 17 which has an inner periphery pad part 28 for holding a center part of a wafer W and an outer periphery pad part 29 which allows a center thereof to oscillate with respect to the inner periphery pad part 28 and can freely move vertically, and can press an outer periphery part of the wafer W onto a chuck table 11 by moving vertically; a carrying arm 16 that can carry the holding pad 17 holding the wafer W onto the chuck table 11, and descends to make the center part of the wafer W contact onto the chuck table 11 to arrange the wafer W on the chuck table 11; and an automatic aligning mechanism 18, provided between the carrying arm 16 and the holding pad 17, which automatically aligns the inclination of a central shaft center O4 of the outer periphery pad part 29 so that the lower surface of the outer periphery pad part 29 becomes parallel to an adsorption surface of the chuck table 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wafer transfer holding device, and more particularly to a wafer transfer holding device that transfers a thinly processed semiconductor wafer onto a chuck table and holds it by suction.

  A semiconductor wafer (hereinafter simply referred to as “wafer”) used for manufacturing a semiconductor device is obtained by cutting an ingot of a semiconductor material into a thin plate shape according to the direction of a crystal axis and polishing it. Also, in the production of semiconductor devices, in the production process such as lithography for forming devices on a wafer, it is necessary to fix the wafer. Usually, a negative air pressure is applied to adsorb the wafer, so-called vacuum adsorption method adsorption. Various processes are performed in a state where the wafer is sucked and held on a stage (usually referred to as “chuck table”) (see, for example, Patent Document 1).

  And when the device on the wafer is completed, the tester and the electrode pad of the device are connected with a prober to perform electrical operation inspection, or the optical inspection of the pattern formed with the inspection machine is the same. In addition, the inspection is performed with the wafer sucked and held on the chuck table.

  In recent years, in the manufacture of semiconductor devices, the diameter of a wafer has been increased to improve the production efficiency, and the diameter of the wafer has been increasing. Further, if the number of wafers that can be taken from one ingot is increased, the manufacturing cost of the wafer is reduced accordingly, and the thickness of the wafer tends to be reduced.

JP 2003-234392 A

  However, the larger the diameter and the thinner the wafer, the more warped due to distortion even if it is polished. In particular, a wafer whose one surface is sealed with a resin is likely to warp when a semiconductor device is formed on the surface. When a wafer with a large degree of warpage is placed on the chuck table having the suction surface, a large gap is created between the chuck table suction surface and the wafer. There is a problem that air flows into the surface and the wafer cannot be sufficiently adsorbed and held. In addition, if processing is performed with a wafer adsorption failure occurring, the wafer may be damaged. In the process of being transferred to the next process, the wafer moves and cannot be accurately placed on the chuck table or the like of the next process. Problems arise.

  In order to solve such a problem, it is conceivable to increase the negative pump pressure by increasing the driving capability of the vacuum pump, that is, to lower the air pressure in the air system channel and the groove. However, for that purpose, it is necessary to prepare a vacuum pump with a large driving capability, which causes various problems such as cost, and cannot cope with a large gap.

  In addition, today, for example, as shown in FIG. 7, the inner peripheral pad portion 101a that holds the central portion of the wafer W in a removable manner and the inner peripheral pad portion 101a can be moved up and down, and the vertical movement thereof. The holding pad 101 having the outer peripheral pad portion 101b capable of pressing the outer peripheral portion of the wafer W onto the chuck table 102, the holding pad 101 holding the wafer W on the inner peripheral pad portion 101a is transferred onto the chuck table 102, and The wafer W is lowered and brought into contact with the suction surface 102a of the chuck table 102, and the transfer arm 103 capable of placing the wafer W on the chuck table 102 and the outer peripheral pad portion 101b are pressed toward the chuck table 102. And a pressure seal disposed above the chuck table 102 with a rod 104a that can be advanced and retracted. And da 104, also known wafer carrier holder device comprising a.

  That is, as shown in FIG. 7A, the wafer transfer holding apparatus shown in FIG. 7 transfers the holding pad 101 holding the wafer W to the inner peripheral pad portion 101a onto the chuck table 102 by the transfer arm 103. Next, as shown in FIG. 5B, the holding pad 101 is lowered together with the transfer arm 103, and the central portion of the wafer W is brought into contact with the suction surface 102a of the chuck table 102 where negative pressure is generated. Subsequently, as shown in FIG. 5C, the rod 104a of the pressure cylinder 104 is protruded to press the outer peripheral pad portion 101b, and the outer peripheral portion of the wafer W is negatively pressured by the pressed outer peripheral pad portion 101b. Is pressed onto the chuck table 102 where the above has occurred. Thus, the wafer W is sucked and held on the chuck table 102, and the wafer W can be held on the chuck table 102a when the holding (negative pressure) on the inner peripheral pad portion 101a side is released. It has become.

  However, in the wafer transfer and holding device as shown in FIG. 7, the outer peripheral pad portion 101b is moved straightly toward the chuck table 102a, that is, by moving up and down linearly, and swinging in the horizontal direction by changing the inclination of the central axis ( It was not structured to swing. Therefore, when the suction surface 102a of the chuck table 102 is inclined or when the wafer W is greatly warped, stress concentration occurs at the time of pressing, and the wafer W cannot be pressed as predetermined. In addition, the chuck on the chuck table 102 becomes unstable and the machining accuracy is adversely affected.

  Accordingly, a wafer transfer and holding device is provided which can even apply a load to the wafer even when the wafer is warped evenly so that the wafer is not damaged, and the wafer can be securely sucked and held by the chuck table. The technical problem which should be solved arises in order to provide, and this invention aims at solving this problem.

  The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 is a wafer transfer holding device for transferring a wafer onto a chuck table, wherein the central portion of the wafer is detachable. The inner peripheral pad portion to be held, and the outer peripheral pad portion that can freely swing and move up and down with respect to the inner peripheral pad portion and can press the outer peripheral portion of the wafer onto the chuck table by the vertical movement. The holding pad having the wafer held by the inner circumferential pad portion, and lowering to bring the center portion of the wafer into contact with the chuck table, A transfer arm capable of placing a wafer on the chuck table, and provided between the transfer arm and the holding pad, and a lower surface of the outer peripheral pad portion is the chuck. Providing wafer transfer holding device and a self-centering mechanism for automatically adjusting the inclination of the central axis of the outer peripheral pad portion so as to be parallel to the suction surface of the table.

  According to this configuration, the outer peripheral pad portion can freely swing and move up and down, and when the outer peripheral portion of the wafer is pressed onto the chuck table, the lower surface of the outer peripheral pad portion is parallel to the chucking surface of the chuck table. As described above, the inclination of the central axis is automatically adjusted by the automatic alignment mechanism, and the outer peripheral pad portion follows the suction surface of the chuck table, so that a load can be uniformly applied to the wafer. As a result, even when the wafer is warped, stress can be prevented from concentrating on a specific portion of the wafer when pressed, the wafer can be prevented from being damaged, and the chucked state at the chuck table can be stabilized.

  According to a second aspect of the present invention, in the configuration according to the first aspect, the self-aligning mechanism includes a first connection portion having a convex spherical surface and a second connection portion having a concave spherical surface, and the first connection portion; The spherical surfaces of the second connecting portion are brought into contact with each other, and one of the first connecting portion and the second connecting portion is fixed to the transport arm side, and the other is fixed to the holding pad side. A wafer transfer holding device is provided.

  According to this configuration, the automatic alignment mechanism is configured such that the spherical surfaces of the first connecting portion having the convex spherical surface and the second connecting portion having the concave spherical surface are brought into contact with each other on the surface. A wafer transfer and holding device with a simple structure and an automatic alignment mechanism can be realized.

  According to a third aspect of the present invention, in the configuration according to the first or second aspect, the outer peripheral pad portion is configured so that the inner peripheral pad portion is in contact with the chuck table via the wafer. Provided is a wafer transfer and holding device that is brought into contact with the wafer via the wafer.

  According to this configuration, it is possible to adjust the inclination of the central axis of the outer peripheral pad portion with reference to the central axis of the inner peripheral pad portion.

  According to a fourth aspect of the present invention, in the configuration according to the first, second, or third aspect, the outer peripheral pad portion is always urged upward away from the wafer between the transfer arm and the outer peripheral pad portion. Provided is a wafer conveyance holding device provided with a biasing spring.

  According to this configuration, the outer peripheral pad portion is resisted against the spring force of the biasing spring that moves the outer peripheral pad upward so that the lower surface of the inner peripheral pad portion is positioned below the lower surface of the outer peripheral pad portion. Only when pressed, the outer peripheral pad is brought into contact with the chuck table via the wafer.

  According to a fifth aspect of the present invention, in the configuration according to the third or fourth aspect, the contact of the outer peripheral pad portion with the chuck table is performed by using a rod of a pressure cylinder disposed above the chuck table. Provided is a wafer transfer and holding device that protrudes toward the pad portion side.

  According to this configuration, the rod of the pressure cylinder is protruded, and the downward movement of the outer peripheral pad portion and the inclination adjustment of the axis of the outer peripheral pad portion by the automatic alignment mechanism can be performed simultaneously.

  According to the invention, the outer peripheral pad portion is configured to be swingable and vertically movable, and the outer peripheral pad portion is provided between the transfer arm and the outer peripheral pad portion when pressing the outer peripheral portion of the wafer onto the chuck table. By the automatic alignment mechanism, the inclination of the central axis of the outer peripheral pad portion is automatically adjusted so that the lower surface of the outer peripheral pad portion is parallel to the suction surface of the chuck table. As a result, even when a wafer with a large amount of warpage follows the chucking surface of the chuck table and the wafer is warped, it is possible to apply a load to the wafer evenly during pressing, so stress is not concentrated on a specific part of the wafer. Thus, damage to the wafer can be prevented. Further, the wafer can be surely sucked and held by the chuck table, the chuck state at the chuck table is stable, and improvement in processing accuracy can be expected.

It is the side view which showed the principal part of the wafer conveyance holding apparatus to which this invention was applied, and was partially cut. It is the elements on larger scale of the wafer conveyance holding apparatus shown in FIG. It is operation | movement explanatory drawing of the wafer conveyance holding apparatus shown in FIG. 1, and is a figure which shows the state before a holding pad adsorb | sucks a wafer. It is operation | movement explanatory drawing of the wafer conveyance holding apparatus shown in FIG. 1, and is a figure which shows the state in the middle of a holding pad adsorbing-holding a wafer and conveying it above a chuck table. FIG. 2 is an operation explanatory diagram of the wafer transfer holding device shown in FIG. 1, in which the holding pad sucks and holds the wafer and is transferred onto the chuck table, and the outer peripheral pad portion presses the wafer when the wafer is placed on the chuck table. It is a figure which shows the state before performing. It is operation | movement explanatory drawing of the wafer conveyance holding apparatus shown in FIG. 1, and shows the state which a holding pad adsorbs and hold | maintains a wafer and is conveyed on a chuck table, and the outer peripheral pad part is pressing the wafer on a chuck table. FIG. It is a figure for demonstrating an example of the conventional wafer conveyance holding device and its problem, (a) shows the state before a holding pad adsorbs a wafer, (b) shows the holding pad adsorbing and holding a wafer. The wafer is transferred onto the chuck table, the wafer is placed on the chuck table, and the outer peripheral pad portion shows a state before the wafer is pressed, and (c) is transferred onto the chuck table while the holding pad sucks and holds the wafer. And it is a figure which shows the state which the outer peripheral pad part is pressing the wafer on the chuck table.

  The present invention eliminates wafer damage by applying a load evenly to a wafer that is warped evenly when pressed, and transporting and holding the wafer so that the wafer can be securely sucked and held by a chuck table. In order to achieve the object of providing an apparatus, in a wafer transfer holding device for transferring a wafer onto a chuck table, an inner peripheral pad portion that holds the central portion of the wafer in a removable manner, and an inner peripheral pad portion. A holding pad having an outer peripheral pad portion that can freely swing and move up and down and can press the outer peripheral portion of the wafer onto the chuck table by the vertical movement, and the inner peripheral pad portion. The held pad is transported onto the chuck table and lowered to center the wafer on the chuck table. A transfer arm that is capable of placing the wafer on the chuck table, and is provided between the transfer arm and the holding pad, and the inclination of the central axis of the outer peripheral pad portion This is realized by including an automatic alignment mechanism that automatically adjusts the lower surface to be parallel to the chucking surface of the chuck table.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are given to the same elements throughout the description of the embodiments. Further, in the following description, expressions indicating directions such as up and down and left and right are not absolute, and are appropriate when each part of the wafer transfer holding device of the present invention is depicted, When the posture changes, it should be interpreted according to the change in posture.

  FIG. 1 is a side view showing a configuration of a main part of a wafer transfer / holding apparatus 10 according to the present invention, and a part of which is a cross-sectional side view. FIG. The wafer conveyance holding device 10 can be widely used in the manufacturing process of semiconductor devices. The wafer transfer holding device 10 applies a negative air pressure (negative pressure) to suck and hold the wafer W, and performs a vacuum chucking type chuck table 11 for performing various processes, and the wafer W from the previous processing step. 11 is provided with a transport mechanism 12 for transporting and setting on 11, a pressure cylinder 13 and the like. The wafer W is obtained by polishing a semiconductor material ingot cut into a thin plate shape according to the direction of the crystal axis, and is formed in a substantially disc shape. The wafer transfer holding device 10 is controlled by a control unit 50 which is a computer, for example, and a program for controlling the wafer transfer device 10 according to a predetermined procedure is incorporated in the control unit 50.

  The chuck table 11 is a disk-shaped table. Further, the chuck table 11 is exposed to a disk-shaped holding table 11a formed with an outer diameter larger than the outer diameter of the wafer W, and an upper surface of the holding table 11a (a suction surface on which the wafer W is placed). It is provided with a suction holding portion 11b which is formed in the same outer diameter as that of the wafer W and which has a disk shape.

  Although not shown, the suction holding portion 11b of the chuck table 11 is provided with a plurality of suction grooves and suction holes communicating with the plurality of grooves. A wafer suction vacuum line 14 provided on the holding table 11a communicates with the suction hole. Therefore, the suction hole functions as a suction port of the wafer suction vacuum line 14. Although not shown, the wafer suction vacuum line 14 is sequentially provided with a pressure gauge, a valve, and a vacuum source. The suction hole, the wafer suction vacuum line 14, the pressure gauge, the valve, the vacuum source, etc. A vacuum suction means 15 is configured. That is, in the wafer vacuum suction means 15, a negative pressure is applied on the suction holding unit 11 b and the wafer W placed on the suction holding unit 11 b of the chuck table 11 is applied while the negative pressure is applied. It can be sucked and held.

  The transfer mechanism 12 includes a transfer arm 16 that can rotate and move up and down, a holding pad 17 that is attached to one end side of the transfer arm 16 so as to be able to move integrally with the transfer arm 16, and between the transfer arm 16 and the holding pad 17. And an elevating shaft 19.

  One end side (base end side) of the transfer arm 16 is fixed to, for example, a robot arm (not shown), and a holding pad 17 is attached to the other end side via a tubular pivot 20.

  The transfer arm 16 can move the holding pad 17 while holding the wafer W from a required position (pre-process position) to a required position (main process position). That is, the wafer W before processing is moved from the previous process position onto the chuck table 11 by the movement of the transfer arm 16, and the wafer W after processing is provided at the required position from the chuck table 11. Can be moved to.

  One end (upper end) side of the pivot portion 20 is fixed to the lower surface of the transfer arm 16, and a holding pad 17 is attached to the other end (lower end) side. In addition, a rod-like lifting shaft 19 is inserted into the pivot 20 through the through-hole 16a of the transport arm 16 in the vertical direction, and can be moved up and down via a tubular bearing metal 21 in the pivot 20. Is retained.

  The elevating shaft 19 has a small-diameter rod portion 19a formed on the lower end side so as to protrude below the pivot portion 20, and an automatic alignment mechanism 18 is provided on the outer periphery of the small-diameter rod portion 19a. The lifting shaft 19 is provided with a ring-shaped regulating plate portion 22 fixed to a substantially middle portion of the lifting shaft 19. The restricting plate portion 22 abuts on the lower surface of the bearing metal 21 when the elevating shaft 19 moves upward to a predetermined position, and restricts the elevating shaft 19 from moving further upward. When the restriction plate 22 is in contact with the lower surface of the bearing metal 21 and the upward movement is restricted, the upper end of the lifting shaft 19 is conveyed through the through hole 16a as shown in FIGS. The arm 16 protrudes slightly from the upper surface and is held.

  Further, a coil spring 23 as an urging spring is placed on the outer periphery of the elevating shaft 19 between a restricting plate 24 attached to the lower surface of the pivot portion 20 and a restricting plate 22 attached to the elevating shaft 19. Arranged. During normal times, the elevating shaft 19 is moved in a state in which the restricting plate 22 is in contact with the lower surface of the bearing metal 21 as shown in FIGS. 1 and 2 by the repulsive force (biasing force) of the coil spring 23. Is held by the bearing metal 21 and the restriction plate 22.

  The automatic alignment mechanism 18 includes a ring-shaped first connecting portion 25 having a convex spherical surface 25a and a second connecting portion 26 having a concave spherical surface 26a. The outer diameters of the first connecting portion 25 and the second connecting portion 26 are substantially equal to the outer diameter of the large-diameter portion of the elevating shaft 19, and each is formed in a disc shape.

  A center hole 25 b is provided at the center of the first connecting portion 25, and a center hole 26 b is provided at the center of the second connecting portion 26. The inner diameter of the center hole 25b in the first connecting portion 25 is substantially equal to the outer diameter of the small diameter rod portion 19a in the lifting shaft 19, and the first connecting portion 25 is moved up and down by fitting the small diameter rod portion 19a into the center hole 25b. 19 is fixed. That is, the first connecting portion 25 is attached to the transport arm 16 side with the convex spherical surface 25a fixed downward.

  On the other hand, the inner diameter of the center hole 26b in the second connecting portion 26 is larger than the outer diameter of the small-diameter rod portion 19a in the elevating shaft 19, and a clearance (play) σ is provided between the small-diameter rod portion 19 and the clearance σ. Thereby, the 2nd connection part 26 is movable to the left-right direction (horizontal direction) with respect to the small diameter rod part 19a and the 1st connection part 25. FIG. The second connecting portion 26 is in a state where the concave spherical surface 26a is in contact with the convex spherical surface 25a of the first connecting portion 25, that is, in a state where the spherical surfaces are in contact with each other. The upper and lower portions are suppressed by the portion 29 and are held by tightening the nut 27 attached to the small-diameter rod portion 19 a below the outer peripheral pad portion 29.

  The holding pad 17 includes an inner peripheral pad portion 28 and an outer peripheral pad portion 29. The inner peripheral pad portion 28 includes a suction holding pad 28a having a substantially circular dish-like suction surface 28c that opens downward to which the wafer W is attached, and a lower surface of the pivot portion 20 that holds the suction holding pad 28a. And a circular pad holder 28b fixedly attached to the pad. The pad holder 28b and the pivot 20 are connected and fixed by a connecting member 30. The suction holding pad 28a is connected to a wafer suction vacuum line 31 on the transport mechanism side in which a suction port 28d is provided in a space surrounded by the suction surface 28c.

  The outer peripheral pad portion 29 has a diameter smaller than the outer diameter of the wafer W, a disk-shaped pressing plate 29a, and a substantially circular cup-shaped connection holder in which an upper surface 29c for attaching the pressing plate 29a to the pivot portion 20 is closed. 29b.

  The upper surface 29c of the connection holder 29b is formed with a center hole 29d having substantially the same size as the center hole 26b of the second connection portion 26, that is, an inner diameter larger than the outer diameter of the small diameter rod portion 19a. Further, the upper surface 29c of the connection holder 29b is provided with a recess 29e substantially at the center thereof. The second connecting portion 26 of the automatic alignment mechanism 18 is fitted into the recess 29e, and the second connecting portion 26 is attached to the connecting holder 29b. Further, through holes 32 and 33 through which the connecting member 30 and the wafer suction vacuum line 31 pass are formed in the upper surface 29c of the connecting holder 29b. The through holes 32 and 33 are respectively provided with a gap between the connecting member 30 and the wafer suction vacuum line 31, and the connection holder 29b is omnidirectional with respect to the connecting member 30 and the wafer suction vacuum line 31 (see FIG. 2 can move (swing) freely in the vertical direction indicated by the arrow A direction and the vertical swing direction indicated by the arrow B in FIG.

  The pressing plate 29a is an annular disk, and is fixed so as to extend horizontally from the outer periphery on the opening side of the connection holder 29b so that the connection holder 29b is disposed at the center thereof, and is integrated with the connection part 29b. It is configured to be movable. Further, a ring-shaped pad material 29f is attached to the outer peripheral portion of the pressing plate 29 on the lower surface (the surface pressing the wafer W). The pad material 29f is made of rubber, a soft resin material, or the like, and is in contact with the upper surface of the wafer W.

  The pressurizing cylinder 13 is disposed above the chuck table 11 with the central axis O2 disposed on the extension of the central axis O1 of the chuck table 11, that is, on the same axis as the chuck table 11. A rod 13a that advances and retracts along the central axis O1 toward the chuck table 11 is provided. This rod 13 a corresponds to the upper end of the lifting shaft 19 held in the pivot portion 20 moved together with the transfer arm 16 between the pressure cylinder 13 and the chuck table 11. When protruding from the pressurizing cylinder 13, the tip (lower end) of the rod 13a collides with the upper end of the elevating shaft 19, and the elevating shaft 19 is moved downward (on the chuck table 11 side) against the urging force of the coil spring 23. It is designed to be pressed.

  3 to 6 are operation diagrams of the wafer transfer and holding device 10 shown in FIGS. 1 and 2. Next, the operation of the wafer transfer apparatus will be described with reference to FIGS.

  First, in the transport mechanism 12, the regulation plate 22 is in contact with the lower surface of the bearing metal 21 by the urging force of the coil spring 23, and the upper end of the lifting shaft 19 passes through the through hole 16 a of the transport arm 16. It rises to a state where it slightly protrudes from the upper surface of the transfer arm 16. Thereby, the outer peripheral pad portion 29 of the holding pad 17 is positioned above the suction holding pad 28 a of the inner peripheral pad portion 28.

  Then, as shown in FIG. 3, the transfer mechanism 12 controls the movement of the holding pad 17 that has not yet held the wafer W together with the transfer arm 16, and moves the holding pad 17 to a predetermined position on the wafer. . Then, the suction holding pad 28a of the inner peripheral pad portion 28 is pressed onto the wafer W, and the wafer suction vacuum line 31 is turned on to create a negative pressure in the suction holding pad 28a. The central portion is sucked and held, and the wafer W is lifted while being sucked and held as shown in FIG.

  Further, the holding pad 17 that sucks and holds the wafer W is moved onto the chuck table 11 together with the transfer arm 16, and the center axis O3 of the holding pad 17 and the lifting shaft 19 is connected to the center axis O1 of the chuck table 11 as shown in FIG. In addition, the wafer W is arranged substantially at the center of the chuck table 11 in accordance with the central axis O3 of the rod 13a of the pressure cylinder 13 and the central axis O4 of the outer peripheral pad portion 29.

  Next, the pressurizing cylinder 13 is operated, the rod 13 a protrudes toward the chuck table 11, and the rod 13 a presses the lifting shaft 19. Then, the elevating shaft 19 is lowered against the urging force of the coil spring 23. When the rod 13a is lowered, the outer peripheral pad portion 29 is lowered integrally with the rod 13a, and the pressing plate 29a of the outer peripheral pad portion 29 contacts the outer peripheral portion of the wafer W through the pad material 29f as shown in FIG. The outer periphery of the wafer W is pressed against the chuck table 11 side. At this time, the outer periphery pad part 29 has the 1st connection part 25 which has the convex spherical surface 25a between the outer periphery pad part 29 and the raising / lowering axis | shaft 19, and the 2nd connection part 26 which has the concave spherical surface 26a. Are provided with an automatic aligning mechanism 18 that abuts each other. The automatic centering mechanism 18 causes the outer peripheral pad portion 29 to automatically move the central axis O4 to freely tilt with the contact center G of the convex spherical surface 25a and the concave spherical surface 26a as the tilting fulcrum, that is, to swing the spherical center. (Swing) can be done.

  Therefore, when the outer peripheral portion of the wafer W is pressed onto the chuck table 11, the lower surface of the outer peripheral pad portion 29 (the lower surface of the suction holding pad 28a) is parallel to the suction holding portion (suction surface) 11b of the chuck table 11. The inclination of the central axis O4 of the outer peripheral pad portion 29 is automatically adjusted by the automatic alignment mechanism 18 to follow the suction holding portion (suction surface) 11b of the chuck table 11, and the pressing force (load) from the outer peripheral pad portion 29 is changed to the wafer W. It takes evenly. As a result, even if the wafer W has a large warp, stress is not concentrated on a specific portion of the wafer W when pressed, so that the wafer W can be prevented from being damaged, and the chuck state on the chuck table 11 is stabilized. Processing accuracy can be improved.

  The wafer W placed on the chuck table 11 is then sucked and held on the holding table 11a by the negative pressure generated on the chuck table 11 side. After the wafer W is attracted and held on the holding table 11 a, the rod 13 a of the pressure cylinder 13 is retracted into the pressure cylinder 13 and the lifting shaft 19 is biased by the coil spring 23 and the outer peripheral pad portion 29. Ascends to the initial position. Next, the transfer mechanism 12 returns the holding pad 17 to the position on the wafer W waiting at a predetermined position, and repeats the same operation again.

  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 configuration of the above-described embodiment, the first connecting portion 25 in the automatic alignment mechanism 18 is fixed to the lifting shaft 19 side, and the second connecting portion 26 is provided on the outer peripheral pad portion 29 side. The connecting portion 25 may be fixed to the outer peripheral pad portion 29 side, and the second connecting portion 26 may be provided on the lifting shaft 19 side.

DESCRIPTION OF SYMBOLS 10 Wafer transfer holding apparatus 11 Chuck table 11a Holding table 11b Suction holding part 12 Transfer mechanism 13 Pressure cylinder 13a Rod 14 Wafer vacuum suction line 15 Wafer vacuum suction means 16 Transfer arm 16a Through hole 17 Holding pad 18 Automatic alignment mechanism 19 Lifting Shaft 19a Small-diameter rod portion 20 Pivot portion 21 Bearing metal 22 Restricting plate portion 23 Coil spring (biasing spring)
24 restricting plate 25 first connecting portion 25a convex spherical surface 25b central hole 26 second connecting portion 26a concave spherical surface 26b central hole 27 nut 28 inner peripheral pad portion 28a suction holding pad 28b pad holder 28c suction surface 28d suction port 29 outer peripheral pad portion 29a Press plate 29b Connection holder 29c Upper surface 29d Center hole 29e Recess 29f Pad material 30 Connection member 31 Vacuum line for wafer suction 32 Through hole 33 Through hole 50 Control unit W Wafer σ Play A, B Moving direction G of outer peripheral pad Contact center (Tilt fulcrum of outer pad part)
O1 Center axis of chuck table O2 Center axis of rod O3 Center axis of pressurizing cylinder O4 Center axis of outer peripheral pad

Claims (5)

A wafer transfer holding device for transferring a wafer onto a chuck table,
An inner peripheral pad portion that removably holds the central portion of the wafer, and a spherical center swinging and vertical movement with respect to the inner peripheral pad portion, and the outer peripheral portion of the wafer being chucked by the vertical movement. A holding pad having an outer peripheral pad portion that can be pressed onto the table;
The wafer is held on the chuck table by transporting the holding pad holding the wafer by the inner peripheral pad portion onto the chuck table and lowering it to bring the center of the wafer into contact with the chuck table. A transfer arm that can be placed on
Automatic alignment that is provided between the transfer arm and the holding pad and automatically adjusts the inclination of the center axis of the outer peripheral pad portion so that the lower surface of the outer peripheral pad portion is parallel to the suction surface of the chuck table. Mechanism,
A wafer transfer and holding device.   The automatic alignment mechanism includes a first connecting portion having a convex spherical surface and a second connecting portion having a concave spherical surface, and the spherical surfaces of the first connecting portion and the second connecting portion are brought into contact with each other, 2. The wafer conveyance holding apparatus according to claim 1, wherein one of the first coupling portion and the second coupling portion is fixed to the transfer arm side, and the other is fixed to the holding pad side. .   The outer peripheral pad portion is in contact with the chuck table via the wafer in a state where the inner peripheral pad portion is in contact with the chuck table via the wafer. The wafer conveyance holding apparatus according to 1 or 2.   The biasing spring which always urges | biases the said outer periphery pad part to the upper direction which leaves | separates from a wafer between the said conveyance arm and the said outer periphery pad part was provided. The wafer conveyance holding apparatus of description. 5. The contact with the chuck table by the outer peripheral pad portion is performed by causing a rod of a pressure cylinder disposed above the chuck table to protrude toward the outer peripheral pad portion side. The wafer conveyance holding apparatus described in 1.