JP2019125755A - Holding device - Google Patents

Abstract

To cause a table holding surface to be automatically switched to an area corresponding to a wafer size.SOLUTION: A holding device 3 includes a suction source 39 communicating with a central suction area of a table 30 through a pipe 31; and a valve mechanism 4 connected to an outer peripheral suction area through a pipe 32 to cause the outer peripheral suction area to selectively communicate with the suction source 39. The valve mechanism 4 includes a chamber 41, a chamber 42 communicating with the chamber 41 through a communication port, and means 49 for opening/closing the communication port, and the opening/closing means 49 includes: a chamber 43 formed in the chamber 41, facing a communication port; a lid 44 for changing the volume of the chamber 43 while moving in the direction of approaching/separating to/from the communication port; an elastic member 45 provided with force to move the lid 44 in the direction of approaching the communication port; a shaft 46 connected to the lid 44 to penetrate the communication port; and a valve 47 located in the chamber 42 mounted on a front end of the shaft 46 to open/close the communication port. The chamber 42 is connected to the suction source 39 through the pipe 33, and the chamber 43 is connected to the suction source 39 through a pipe 34, and the pipe 32 communicating with the outer peripheral suction area is connected to the chamber 41.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a holding device capable of sucking and holding workpieces of different sizes.

  A holding table provided in a grinding apparatus or the like and holding a wafer, for example, an 8-inch wafer or a 12-inch wafer by suction is provided with a central holding surface and an annular holding surface outside the central holding surface. It is possible to suction and hold the wafer appropriately without changing the holding table itself, corresponding to wafers of a plurality of sizes (see, for example, Patent Document 1).

  When sucking and holding an 8-inch wafer with such a holding table (so-called universal chuck table), only the central holding surface is communicated with the suction source, and when holding a 12-inch wafer, the central holding surface and the annular holding The surface is in communication with the suction source. That is, the holding table has a first valve in the first suction passage connecting the central holding surface to the suction source, and a second valve in the second suction passage connecting the annular holding surface to the suction source. When holding an 8-inch wafer, only the first valve is opened, and when holding a 12-inch wafer, the first valve and the second valve are opened to switch the holding area.

JP, 2001-038556, A

  Since the grinding apparatus is set in advance to process an 8-inch wafer or a 12-inch wafer before starting the grinding process, the first valve and the second valve are set according to the wafer size setting. And are operating. In the manual type grinding apparatus, the operator sets the wafer size. On the other hand, in the full-automatic grinding apparatus, for example, the cassette containing a plurality of wafers is placed on the cassette stage, and the size of the wafer carried into the grinding apparatus is recognized from the information on the cassette size. .

Therefore, there is a problem that the holding table can not properly hold the wafer by suction if there is a difference between the wafer size set in advance in the grinding apparatus and the size of the wafer actually carried into the grinding apparatus and processed from this.
Therefore, when grinding or the like is performed on various types of wafers having different sizes, the holding surface of the holding table is automatically switched to the holding area according to the wafer size even if the wafer size is not set in the processing apparatus. There is a problem in that the wafer can be reliably held by suction with a holding surface of an appropriate area.

  The present invention for solving the above-mentioned problems is a holding device capable of suctioning and holding workpieces of different sizes by switching suction areas, which comprises a central suction area and an outer peripheral suction area surrounding the central suction area. And a suction source communicated with the central suction area via the first communication pipe, and the outer peripheral suction area connected via the second communication pipe to select the outer peripheral suction area and the suction source And a valve mechanism communicating with each other, the valve mechanism selectively opening / closing the first chamber, a second chamber adjacent to the first chamber and in communication via the communication port, and the communication port Opening and closing means, the opening and closing means being disposed in the first room and having a opening facing the communication port, the third room closing the opening and the communication port A lid for changing the volume in the third chamber while moving in an approaching or separating direction, and the lid An elastic member having a force for moving in a direction approaching the communication port, a shaft connected to the lid and penetrating the communication port, and a tip of the shaft attached to the tip of the shaft and positioned in the second chamber and the communication port And the second chamber is connected to the suction source via a third communication pipe, and the third chamber receives the suction via a fourth communication pipe. The second communication tube connected to the source and in communication with the outer peripheral suction area is connected to the first chamber, and covers the central suction area, and when the workpiece is placed, the workpiece is in the central area. The first chamber is opened to the outside air through the outer peripheral suction region, and the third chamber in communication with the suction source is depressurized to reduce its volume and the pressure is reduced via the shaft. The communication port is closed by the valve pulled toward the opening, and the second chamber from the outer peripheral suction area When the workpiece is placed covering the central suction area and the outer peripheral suction area, the workpiece is sucked and held in the central suction area and the outer peripheral suction area is The holding device is connected to the suction source via the second communication pipe, the first chamber, the communication port, the second chamber, and the third communication pipe, and is held by suction.

  Let A be the cross-sectional area of the gap between the communication port and the shaft, B be the area obtained by removing the cross-sectional area of the shaft from the area of the lid, H be the air pressure in the first chamber, and the elastic member When the force for moving the lid in the direction approaching the communication port is W, B × H> A × H + W.

  The cross sectional area in the third communication pipe is preferably smaller than the cross sectional area in the fourth communication pipe.

  The valve mechanism may be independently connected to the second outer peripheral suction area, further including a second outer peripheral suction area surrounding the outer peripheral suction area.

  A holding device according to the present invention is a holding device capable of suctioning and holding workpieces different in size by switching suction regions, and having a table having a central suction region and an outer peripheral suction region surrounding the central suction region; A suction source communicated with the central suction area through the first communication pipe; and a valve mechanism coupled to the outer peripheral suction area through the second communication pipe and selectively communicating the outer peripheral suction area with the suction source. The valve mechanism includes a first chamber, a second chamber adjacent to the first chamber and in communication via a communication port, and opening / closing means for selectively opening / closing the communication port. A third chamber having an opening disposed in the first chamber and formed to face the communication opening, and a volume in the third chamber while moving in a direction closing the opening and approaching or separating from the communication opening Lid to change the pressure, and force to move the lid in the direction to approach the communication port A second chamber connected to the lid and a shaft connected to the lid and penetrating the communication port, and a valve mounted at the tip of the shaft and positioned in the second chamber to selectively open and close the communication port; Is connected to the suction source via the third communication tube, the third chamber is connected to the suction source via the fourth communication tube, and the second communication tube communicating with the outer peripheral suction area is the first chamber When the workpiece (for example, an 8-inch wafer) is placed covering the central suction area, the workpiece is sucked and held in the central suction area, and the first chamber passes through the peripheral suction area. The third chamber opened to the outside air and communicated with the suction source is decompressed and reduced in volume, and the communication port is closed with a valve pulled toward the opening through the shaft to open the second suction chamber from the outer peripheral suction region It is possible to prevent the outside air from entering the room, or the top of the table It eliminates the suction force from leaking. Further, when the workpiece (for example, 12-inch wafer) is placed covering the central suction area and the peripheral suction area of the table, the workpiece is sucked and held in the central suction area, and the second communication is performed. Suction is held in an outer peripheral suction area connected to the suction source via the pipe, the first chamber, the communication port, the second chamber, and the third communication pipe. That is, even if the wafer size is not set in the processing apparatus provided with the holding device, the holding surface of the table is automatically switched to the holding area according to the wafer size, and the workpiece is reliably sucked by the holding surface of the appropriate area. You will be able to hold it.

  The cross-sectional area in the third communication pipe is smaller than the cross-sectional area in the fourth communication pipe, so that the central suction area is covered and the workpiece (for example, 8-inch wafer) is placed on the opening and closing. The means can be reached more quickly in the state where the communication port is closed by the valve.

  When the table further includes a second outer peripheral suction area surrounding the outer peripheral suction area, the valve mechanism is disposed independently in the second outer peripheral suction area, whereby the central suction area and the outer peripheral suction area are provided. When suctioning and holding the workpiece only by suction, vacuum leakage of the second outer peripheral suction area can be prevented, and the holding surface of the table can be made an appropriate holding area.

It is a perspective view showing an example of a grinding device. It is sectional drawing which shows an example of a grinding means and a holding | maintenance apparatus. FIG. 3A is a cross-sectional view for explaining a case where the proximity sensor detects a state in which the communication port is opened in the valve mechanism. FIG. 3B is a cross-sectional view for explaining a case where the proximity sensor detects a state in which the communication port is closed by the valve in the valve mechanism. FIG. 4A is a cross-sectional view for explaining a case where the transmission type optical sensor detects a state in which the communication port is opened in the valve mechanism. FIG. 4B is a cross-sectional view for explaining a case where the transmission type optical sensor detects a state in which the communication port is closed by the valve in the valve mechanism. It is sectional drawing which shows the state which the suction source operated in the state which covered the center suction area | region of the table, and the 8-inch wafer was mounted. After the suction source is activated while the central suction area of the table is covered and the 8-inch wafer is placed, the valve is pulled through the shaft, the communication port is closed, and the outside air from the peripheral suction area to the second chamber It is sectional drawing which shows the state by which approach was prevented. A cross-sectional view showing a state in which the suction source operates with the 12-inch wafer placed on the central suction area and the outer-peripheral suction area of the table, and the 12-inch wafer is sucked and held by the central suction area and the outer-peripheral suction area. It is. It is sectional drawing which shows the state which the suction source operated in the state which covered the center suction area | region of the table, and the 8-inch wafer was mounted. After the suction source is activated while the central suction area of the table is covered and the 8-inch wafer is placed, the valve is pulled through the shaft, the communication port is closed, and the outside air from the peripheral suction area to the second chamber It is sectional drawing which shows the state by which approach was prevented. A cross-sectional view showing a state in which the suction source operates with the 12-inch wafer placed on the central suction area and the outer-peripheral suction area of the table, and the 12-inch wafer is sucked and held by the central suction area and the outer-peripheral suction area. It is. When a table further has a 2nd outer periphery suction area which encloses an outer periphery suction area, it is an explanatory view showing the state where a valve mechanism is arranged independently in the 2nd outer periphery suction area.

The grinding apparatus 1 shown in FIG. 1 is a holding device 3 according to the present invention capable of suctioning and holding workpieces of different sizes (for example, 8-inch wafer W1 or 12-inch wafer W2), and workpieces held by the holding device 3 And grinding means 6 equipped with a grinding wheel 64 for grinding an object.
The 8-inch wafer W1 and the 12-inch wafer W2 are, for example, semiconductor wafers having a circular plate-like outer shape whose base material is silicon, and the lower surface (holding surface) in FIG. 1 is partitioned in a grid by dividing lines. Devices are respectively formed in the respective regions, and a protective tape (not shown) is adhered and protected.

  A column 17 stands upright on the rear side (+ X direction side) on the base 10 of the grinding apparatus 1, and on the front surface thereof, a grinding feed means for feeding the grinding means 6 in the Z axis direction (vertical direction) 7 is provided. The grinding feed means 7 includes a ball screw 70 having an axial center in the Z-axis direction, a pair of guide rails 71 disposed parallel to the ball screw 70, a motor 72 coupled to the ball screw 70 and rotating the ball screw 70, and The motor 72 rotates the ball screw 70. The motor 72 rotates the ball screw 70. The motor 72 rotates the ball screw 70. Then, the lift plate 73 is guided by the guide rail 71 to reciprocate in the Z-axis direction, and the grinding means 6 supported by the holder 74 also reciprocates in the Z-axis direction.

  The grinding means 6 is attached to the lower end of the rotary shaft 60, a rotary shaft 60 whose axial direction is the Z-axis direction, a housing 61 rotatably supporting the rotary shaft 60, a motor 62 rotating the rotary shaft 60, and And a grinding wheel 64 removably connected to the mount 63. The grinding wheel 64 includes a wheel base 640, and a grinding stone 641 having a substantially rectangular parallelepiped outer shape and disposed in a plurality of rings on the lower surface of the wheel base 640. The grinding wheel 641 is formed by adhering diamond abrasive grains or the like with an appropriate bonding agent.

  A grinding water jet nozzle 18 is disposed in the vicinity of the grinding means 6. The grinding water jet nozzle 18 jets the grinding water supplied from the grinding water supply source 19 toward the contact site between the rotating grinding wheel 64 and the workpiece (12-inch wafer W2) shown in FIG. Cool and remove grinding debris generated by grinding.

  The holding device 3 disposed on the base 10 of the grinding apparatus 1 is surrounded from the periphery by the cover 16 and is disposed below the bellows cover 15 which is connected to the cover 16 and the cover 16 and extends and contracts in the X-axis direction. Reciprocating movement on the base 10 in the X-axis direction is possible by means of X-axis direction moving means (not shown).

  The holding device 3 includes a table 30 having a central suction area 300a and an outer peripheral suction area 300b surrounding the central suction area 300a, and a suction source 39 communicated with the central suction area 300a via the first communication pipe 31; The valve mechanism 4 is connected to the outer peripheral suction area 300 b via the second communication pipe 32 and selectively communicates the outer peripheral suction area 300 b and the suction source 39.

The table 30 has, for example, a circular outer shape, is provided with an adsorbing portion 300 made of a porous material or the like and adsorbing a workpiece, and a frame body 301 supporting the adsorbing portion 300. The table 30 is rotatable about an axis in the Z-axis direction by rotation means (not shown) disposed below the table 30.
The suction portion 300 is made of a non-air-permeable material and is concentrically arranged around the center of the table 30 by a partition portion 302 to surround the central suction region 300a and the central suction region 300a in a Berm-Cohen shape. It is divided into 300b.

  The exposed surface of the suction unit 300 serves as a holding surface whose area can be changed according to the size of the workpiece. That is, the upper surface (exposed surface) of the central suction area 300a has a diameter corresponding to the diameter of the 8-inch wafer W1, and serves as a suction holding surface when the table 30 suction-holds the 8-inch wafer W1. The outer diameter of the upper surface of the outer peripheral suction area 300b has a size corresponding to the diameter of the 12-inch wafer W2, and when the table 30 sucks and holds the 12-inch wafer W2, as shown in FIG. The upper surface of 300a and the upper surface of the outer peripheral suction area 300b become a suction holding surface.

  As shown in FIG. 2, the exposed surface of the suction unit 300 (the upper surface of the central suction region 300 a and the upper surface of the outer peripheral suction region 300 b) is formed in a conical surface having a very gentle inclination with the rotation center of the table 30 as a vertex. There is. Further, below the table 30, a tilt adjustment mechanism (not shown) connected to the table 30 via a coupling or the like is disposed. The tilt adjusting mechanism can adjust the tilt of the exposed surface of the suction unit 300 with respect to the grinding surface of the grinding wheel 641 so that both surfaces are parallel as shown in FIG. 2, for example.

  As shown in FIG. 2, one end 31 a side of the first communication pipe 31 made of metal piping or flexible resin tube penetrates the frame body 301 of the table 30 in the vertical direction, and the central suction area 300 a is formed. It is in communication. The other end 31 b of the first communication pipe 31 is in communication with a suction source 39 formed of a vacuum generator such as a vacuum pump or an ejector via an on-off valve 390. The on-off valve 390 switches between a state in which the suction source 39 and the table 30 are in communication and a state in which the suction source 39 and the table 30 are not in communication.

The valve mechanism 4 includes, for example, a casing 40 having a cylindrical outer shape with a hollow inside, and an annular plate-shaped partition plate 400 is disposed at a predetermined height position on the inner peripheral surface of the casing 40 ing. The inside of the casing 40 is separated by the partition plate 400 via the first chamber 41 located on the lower side of the interior of the casing 40 and the communication port 401 adjacent to the first chamber 41 and formed at the center of the partition plate 400. It is divided into a second chamber 42 (upper side inside the casing 40) in communication. Further, inside the casing 40, an opening / closing means 49 for selectively opening / closing the communication port 401 is disposed.
In addition, the casing 40 is in the state of facing sideways, the first chamber 41 may be on the −X direction side, and the second chamber 42 may be on the + X direction side.

The other end 32 b side of the second communication pipe 32 is in communication with the first chamber 41, and one end 32 a side of the second communication pipe 32 is in communication with the outer peripheral suction area 300 b of the table 30.
One end side of the third communication pipe 33 is in communication with the second chamber 42, and the other end side of the third communication pipe 33 joins the first communication pipe 31, for example, to the suction source 39. It is in communication.

  The opening / closing means 49 is disposed in the first chamber 41 and has a third chamber 43 having an opening 430 formed opposite to the communication opening 401 in the Z-axis direction, and closes the opening 430 to approach the communication opening 401 or A lid 44 for changing the volume in the third chamber 43 while moving in a separating direction, an elastic member 45 having a force for moving the lid 44 in a direction approaching the communication port 401, and the lid 44 connected to the communication port A shaft 46 penetrating the shaft 401 and a valve 47 mounted at the tip of the shaft 46 and positioned in the second chamber 42 to selectively open and close the communication port 401 are constituted.

The third chamber 43 is a chamber (a space surrounded by the lower surface of the lid 44 and the inner circumferential surface of the cylindrical wall 412) formed by the cylindrical wall 412 erected in the Z-axis direction in the first chamber 41. The opening on the upper side of the cylindrical wall 412 is a circular opening 430 closed by the lid 44. One end of a fourth communication pipe 34 is connected to the third chamber 43, and the other end of the fourth communication pipe 34 joins, for example, the first communication pipe 31 and communicates with the suction source 39. doing.
For example, the cross-sectional area in the third communication pipe 33 is smaller than the cross-sectional area in the fourth communication pipe 34.

  In the example shown in FIG. 2, the elastic member 45 having a force for pushing up the lid 44 in the direction approaching the communication port 401 is a compression coil spring which shrinks shorter than the natural length and tries to return to the natural length by the stored biasing force. The biasing force pushes up the lid 44. The elastic member 45 is disposed at the center of the third chamber 43, and its lower end is fixed to the lower surface of the casing 40, and its upper end is fixed to the lower surface of the lid 44.

  The lid 44 closing the opening 430 has, for example, a circular flat outer shape, and its diameter is slightly smaller than the inner diameter of the cylindrical wall 412. An outer peripheral edge of the lid 44 is in contact with an inner peripheral surface of the cylindrical wall 412, and the lid 44 is slidably supported in the Z-axis direction by the elastic member 45 with the opening 430 closed. When the lid 44 rises to the upper end of the third chamber 43, the volume of the third chamber 43 is maximized, and when the lid 44 is lowered to the lower edge of the third chamber 43, the volume of the third chamber 43 is minimized.

The lower end side of a columnar shaft 46 is fixed to the upper surface of the lid 44. The shaft 46 passes through the communication port 401, and the upper end side of the shaft 46 is fixed to the lower surface of the valve 47.
The valve 47 has, for example, a circular flat outer shape, the diameter of which is larger than that of the communication port 401, and the lower surface is seated on the upper surface of the partition plate 400 to close the communication port 401. It will be in the state.

  The elastic member 45 is not limited to the example arrange | positioned in the 3rd chamber 43 like the example shown in FIG. The elastic member is, for example, a tension spring, and is disposed at the center of the second chamber 42, and its upper end is fixed to the top wall of the casing 40, and its lower end is fixed to the upper surface of the valve 47. It may be In this case, the biasing force for returning to the natural length after the tension spring, which is an elastic member, is extended longer than the natural length is a force for moving (liding up) the lid 44 in the direction approaching the communication port 401.

  The valve mechanism 4 may have, for example, a function (sensor) for detecting whether the valve 47 is in a state in which the communication port 401 is closed or in an open state. By detecting the open / close state of the communication port 401 by the valve 47 by the sensor, it can be determined whether or not the outer peripheral suction area 300b shown in FIG. 2 is open to the outside air, therefore the table 30 is only in the central suction area 300a. It can be determined whether suction holding is performed or suction holding is performed between the central suction area 300a and the outer peripheral suction area 300b.

As an example of the sensor, for example, as shown in FIGS. 3A and 3B, a proximity sensor 406 such as a capacitive type is disposed at a predetermined height position in the second room 42. ing. The proximity sensor 406 is fixed, for example, at the center of the top wall of the casing 40, and faces the valve 47 in the Z-axis direction. As shown in FIG. 3A, since the valve 47 is not lowered and is positioned at a predetermined height in the second chamber 42, the valve 47 approaches the reaction portion 406a of the proximity sensor 406. The proximity sensor 406 detects that the communication port 401 is not closed by the valve 47. On the other hand, as shown in FIG. 3B, when the valve 47 is lowered to reach the height position in the state where the communication port 401 is closed, the reaction portion 406a and the valve 47 are separated and the inside of the proximity sensor 406 is separated. The proximity sensor 406 detects that the communication port 401 is closed by the valve 47 based on the change in the capacitance, since the capacitance of the conductor electrode of the sensor decreases.
The proximity sensor may be embedded in the lower surface of the valve 47 so that the lower surface is flush, for example. In this case, the proximity sensor detects that the valve 47 is closed by the valve 47 being lowered and the partition plate 400 being close. Further, the proximity sensor 406 may be, for example, an inductive proximity sensor or the like.

  For example, as shown in FIGS. 4A and 4B, the light emitting unit 408 attached to the inner circumferential surface of the casing 40 at a predetermined height position in the second room 42, not the proximity sensor 406. A transmissive optical sensor may be disposed, which includes (−X direction side) and a light receiving unit 409 (+ X direction side) attached to the inner circumferential surface of the casing 40. The inspection light is projected from the light emitting unit 408 toward the light receiving unit 409. Then, as shown in FIG. 4A, the inspection light between the light emitting unit 408 and the light receiving unit 409 is blocked by the valve 47, so that the communication port 401 is not closed by the valve 47. To detect. On the other hand, as shown in FIG. 4B, the light sensor is closed by the valve 47 whose communication port 401 is lowered because the inspection light between the light emitting unit 408 and the light receiving unit 409 is not blocked by the valve 47. Detect what is being done.

The operation of each configuration of the holding device 3 in the case where the circular plate-like 8-inch wafer W1 is suctioned and held by the holding device 3 shown in FIG. 1 will be described below.
First, as shown in FIG. 5, the central suction area 300a is arranged such that the center of the upper surface of the central suction area 300a serving as the holding surface of the table 30 and the center of the 8-inch wafer W1 substantially coincide with each other. Is placed on top of the When the suction source 39 is not in operation, the elastic member 45 has, for example, a natural length, and the communication port 401 is not closed by the valve 47.

  While the on-off valve 390 shown in FIG. 5 is in the open state, the suction source 39 operates. The suction force generated by the suction source 39 is transmitted to the upper surface of the central suction area 300a through the first communication pipe 31, whereby the table 30 suction-holds the 8-inch wafer W1 on the central suction area 300a. The suction force leaks from the upper surface of the outer peripheral suction area 300b because the upper surface of the outer peripheral suction area 300b is not closed by the 8-inch wafer W1, and the first chamber 41 has the outer peripheral suction area 300b of the table 30 and the second It will be in the state open | released external air through the communicating pipe 32. As shown in FIG.

In the valve mechanism 4, for example, the area of the cross section of the gap between the communication port 401 and the shaft 46 (annular cross section in this embodiment) is A, and the area of the top surface of the lid 44 is the cross section of the shaft 46 An area is B, an air pressure of the first chamber 41 is H, and a force to move the lid 44 of the elastic member 45 in a direction approaching the communication port 401, that is, in the present embodiment, a compression that pushes the lid 44 upward. When the biasing force of the spring is W,
B × H> A × H + W ........... (Equation 1)
The diameter of the communication port 401, the diameter of the shaft 46, and the diameter of the lid 44 are determined so as to satisfy
When the suction source 39 performs suction, air is sucked from the inside of the second chamber 42 through the third communication pipe 33, and air is suctioned from the inside of the third chamber 43 through the fourth communication pipe 34. Be done. Here, in the first chamber 41 and the second chamber 42, suction of the outside air is performed from the outer peripheral suction region 300b, and new air flows in through the second communication pipe 32, while the third chamber 43 In the inside, since the lid 44 closes the opening 430 and only air is sucked from the fourth communication pipe 34, the pressure in the third chamber 43 is reduced (the negative pressure is stronger Become). Therefore, the lid 44 slides on the inner peripheral surface of the cylindrical wall 412 against the elastic member 45 in the −Z direction separated from the communication port 401 while keeping the lid 430 closed the opening 430, and the third The volume in the room 43 decreases.

  Therefore, with the movement of the lid 44 in the -Z direction, the valve 47 is pulled in the -Z direction toward the opening 430 through the shaft 46 to which the lid 44 is connected, as shown in FIG. The lower surface of the valve 47 is seated on the upper surface of the partition plate 400, and the communication port 401 is closed by the valve 47. As a result, the outside air can be prevented from entering the second chamber 42 from the outer peripheral suction area 300 b. Furthermore, since new air does not flow into the second chamber 42 and air in the second chamber 42 is drawn, the pressure in the second chamber 42 is reduced (the negative pressure becomes stronger).

  Thus, the pressure in the third chamber 43 and the second chamber 42 is reduced, and the pressure in the third chamber 43 and the fourth communication pipe 34, the second chamber 42 and the third communication pipe 33, and The air flow rate in one communication pipe 31 is, for example, about 0 (L / min) or a value slightly larger than 0 (L / min). Then, the pressure H of the first chamber 41 becomes the atmospheric pressure. Further, (Expression 1) is in a satisfied state, that is, a force of B × H (in FIG. 8, a force by which the lid 44 is pushed in the −Z direction by air pressure)> A × H (in FIG. 8) Since the force by which the valve 47 is pushed in the + Z direction by air pressure) + W (the urging force in the + Z direction applied by the elastic member 45 to the lid 44 in FIG. 8) is maintained, each force in the valve mechanism 4 is balanced. Until the suction source 39 is stopped, the table 30 continues to reliably hold the 8-inch wafer W1 in the central suction area 300a without generating vacuum leak from the outer peripheral suction area 300b. Can.

  As in the present embodiment, by making the cross sectional area in the third communication pipe 33 smaller than the cross sectional area in the fourth communication pipe 34, the central suction area 300a is covered and the 8-inch wafer W1 is placed. In the case where the third chamber 43 can be depressurized earlier than the other chambers, the opening / closing means 49 can reach the state in which the communication port 401 is blocked by the valve 47 more quickly. it can.

The operation of each configuration of the holding device 3 in the case where the circular plate-like 12-inch wafer W2 is suctioned and held by the holding device 3 shown in FIG. 1 will be described below.
First, as shown in FIG. 7, the 12 inch wafer W2 substantially aligns the center of the top surface of the central suction area 300a of the table 30 with the center of the 12 inch wafer W2 It is placed on the upper surface of the suction area 300b.
When the suction source 39 is not in operation, the elastic member 45 has a natural length, and the communication port 401 is not closed by the valve 47.

  While the on-off valve 390 shown in FIG. 7 is in the open state, the suction source 39 operates. The suction force generated by the suction source 39 generates a flow of air in a direction toward the suction source 39 in the first communication tube 31 so that the table 30 sucks and holds the 12-inch wafer W2 on the central suction area 300a. . At the same time, the suction force generated by the suction source 39 sucks the second communication pipe 32, the first chamber 41, the communication port 401 in the open state, the second chamber 42, and the third communication pipe 33. A flow of air in the direction to the source 39 occurs, and the table 30 sucks and holds the 12-inch wafer W2 also on the outer peripheral suction area 300b.

  Since the elastic member 45 has a natural length before the suction source 39 is activated and the communication port 401 is not closed by the valve 47, the second communication tube 32 is operated when the suction source 39 is activated. The suction path consisting of the third communication pipe 33 is immediately formed, and the 12-inch wafer W2 is suctioned and held on the central suction area 300a and the outer peripheral suction area 300b of the table 30. That is, although the inside of the third chamber 43 is also sucked via the fourth communication pipe 34, at the same time the suction path consisting of the second communication pipe 32 to the third communication pipe 33 is also sucked, so the valve The mechanism 4 and each communicating pipe are in a state close to vacuum without lowering of the valve 47. Therefore, since the internal pressure of each chamber is also in the equilibrium state, the valve 47 does not descend thereafter and the communication port 401 is not closed. Therefore, the table 30 has a 12-inch wafer in the central suction area 300a and the outer circumference suction area 300b. W2 can be reliably suctioned and held.

As described above, the holding device 3 according to the present invention includes the table 30 having the central suction area 300a and the outer peripheral suction area 300b surrounding the central suction area 300a, and the central suction area 300a via the first communication pipe 31. And a valve mechanism 4 connected to the outer peripheral suction area 300b via the second communication pipe 32 and selectively connecting the outer peripheral suction area 300b and the suction source 39; Includes a first chamber 41, a second chamber 42 adjacent to the first chamber 41 and in communication via the communication port 401, and opening / closing means 49 for selectively opening / closing the communication port 401, The means 49 moves in a direction in which the third chamber 43 is disposed in the first chamber 41 and has an opening 430 formed facing the communication port 401, and the opening 430 is closed and approaches or separates from the communication port 401. While A lid 44 for changing the volume in the chamber 43, an elastic member 45 having a force for moving the lid 44 in a direction approaching the communication port 401, a shaft 46 connected to the lid 44 and penetrating the communication port 401; 46. A valve 47 mounted on the tip of the 46 and positioned in the second chamber 42 and selectively opening and closing the communication port 401, and the second chamber 42 is connected to the suction source 39 via the third communication tube 33. The third chamber 43 is connected to the suction source 39 via the fourth communication pipe 34, and the second communication pipe 32 communicating with the outer peripheral suction area 300b is connected to the first chamber 41. Therefore, when the workpiece (for example, an 8-inch wafer) is placed covering the central suction area 300a, the workpiece is sucked and held in the central suction area 300a, and the first chamber 41 is exposed to the outside air through the outer peripheral suction area 300b. Open to The third chamber 43 communicated with the suction source 39 is decompressed to reduce its volume, and the communication port 401 is closed by the valve 47 pulled toward the opening 430 through the shaft 46 to It is possible to prevent the outside air from entering the second chamber 42, and the suction force does not leak from the upper surface of the table 30. When a workpiece (for example, a 12-inch wafer) is positioned in the central suction area 300a and the outer peripheral suction area 300b of the table 30, the workpiece is sucked and held in the central suction area 300a and the second Suction is held in the outer peripheral suction area 300 b connected to the suction source 39 via the communication pipe 32, the first chamber 41, the communication port 401, the second chamber 42 and the third communication pipe 33.
As described above, even if the wafer size is not set to the grinding apparatus 1 including the holding device 3, the holding surface of the table 30 is automatically switched to the holding area according to the wafer size, and the processing is performed with the holding surface of an appropriate area. It will be possible to suction and hold things securely.

  The holding device according to the present invention is not limited to the above-described example, and the shapes and the like of the respective configurations of the holding device 3 and the grinding device 1 illustrated in the attached drawings are not limited to this. The present invention can be appropriately changed within the range where the effects of the present invention can be exhibited.

  For example, the opening / closing means 49D of the holding device 3 shown in FIG. 8 is obtained by changing a part of the components of the opening / closing means 49 shown in FIG. The opening / closing means 49D is disposed in the first chamber 41 and has a third chamber 43D having an opening 434 formed opposite to the communication port 401, and closes the opening 434 in a direction to approach or separate from the communication port 401. A lid 44D for changing the volume in the third chamber 43D while moving, and an elastic member 45D having a force for moving the lid 44D in a direction to approach the communication port 401 are provided. It is similar to the opening and closing means 49 shown.

  The third chamber 43D is a chamber (a space surrounded by the lower surface of the lid 44D and the inner circumferential surface of the elastic member 45D) formed by the elastic member 45D disposed in the first chamber 41. The elastic member 45D is a bellows-like cylinder made of a predetermined rubber, plastic, metal or the like, and the lower end side is fixed to the bottom surface of the casing 40 so as to be extensible and contractible in the Z-axis direction. The opening on the upper side of the third chamber 43D is a circular opening 434 closed by a circular flat lid 44D. In the present embodiment, the lid 44D and the elastic member 45D are integrated, and the opening 434 is closed. One end of the fourth communication pipe 34 is connected to the third chamber 43D, and the other end of the fourth communication pipe 34 joins, for example, the first communication pipe 31 and communicates with the suction source 39. doing.

The operation of each configuration of the holding device 3 in the case where the circular plate-like 8-inch wafer W1 is sucked and held by the holding device 3 provided with the opening / closing means 49D will be described below.
First, as shown in FIG. 8, an 8-inch wafer W1 is placed on the upper surface of the central suction area 300a. When the suction source 39 is not in operation, the elastic member 45D is, for example, a natural length, and the communication port 401 is not closed by the valve 47.

  While the on-off valve 390 shown in FIG. 8 is opened, the suction source 39 is activated, and the table 30 sucks and holds the 8-inch wafer W1 on the central suction area 300a. The suction force leaks from the upper surface of the outer peripheral suction area 300 b, and the first chamber 41 is open to the outside air through the outer peripheral suction area 300 b of the table 30 and the second communication pipe 32.

In the valve mechanism 4, the area of the annular cross section of the gap between the communication port 401 and the shaft 46 is A, and the area of the top surface of the lid 44 D excluding the cross sectional area of the shaft 46 is B. The pressure of H is set to H, and the force to move the lid 44D of the elastic member 45D in the direction approaching the communication port 401, that is, in this embodiment, the repulsive force of the bellows that pushes the lid 44D upward in the folded state If you
B × H> A × H + W ........... (Equation 1)
The diameter of the communication port 401, the diameter of the shaft 46, and the diameter of the lid 44D are determined so as to satisfy the following.
As the suction source 39 performs suction, air is sucked from the second chamber 42 and air is sucked from the third chamber 43. Here, while new air flows into the first chamber 41 and the second chamber 42 through the second communication pipe 32, the air in the third chamber 43 is only sucked. Therefore, the pressure in the third chamber 43 is reduced. Therefore, the lid 44D descends against the elastic member 45D in the -Z direction separated from the communication port 401, and the volume in the third chamber 43 decreases (the elastic member 45D is folded) .

  Therefore, as the lid 44D is lowered, the valve 47 is pulled downward toward the opening 434 through the shaft 46, and the communication port 401 is closed by the valve 47 as shown in FIG. As a result, entry of outside air from the outer peripheral suction area 300b into the second chamber 42 is prevented, and the second chamber 42 is depressurized because new air does not flow into it and is sucked.

  Thus, the pressure in the third chamber 43 and the second chamber 42 is reduced, and the pressure in the third chamber 43 and the fourth communication pipe 34, the second chamber 42 and the third communication pipe 33, and The air flow rate in one communication pipe 31 is, for example, about 0 (L / min) or a value slightly larger than 0 (L / min). Then, the pressure H of the first chamber 41 becomes the atmospheric pressure. Further, (Expression 1) is in a satisfied state, that is, a force of B × H (in FIG. 9, a force by which the lid 44D is pushed in the −Z direction by atmospheric pressure)> A × H (in FIG. 9) Each force in the valve mechanism 4 is balanced because the force by which the valve 47 is pushed in the + Z direction by air pressure) + W (the repulsive force in the Z direction applied by the elastic member 45D to the lid 44D in FIG. 8) is maintained. Until the suction source 39 is stopped, the table 30 continues to reliably hold the 8-inch wafer W1 in the central suction area 300a without generating vacuum leak from the outer peripheral suction area 300b. Can.

The operation of each configuration of the holding device 3 in the case where the disk-like 12-inch wafer W2 shown in FIG. 10 is suctioned and held by the holding device 3 provided with the opening / closing means 49D will be described below.
First, the 12-inch wafer W2 is placed on the upper surface of the central suction area 300a of the table 30 and the upper surface of the outer peripheral suction area 300b. In a state where the suction source 39 is not operated, the elastic member 45D is a natural length, and the communication port 401 is not closed by the valve 47.

  The on-off valve 390 shown in FIG. 10 is opened and the suction source 39 is activated. The suction force generated by the suction source 39 generates a flow of air toward the suction source 39 in the first communication passage 31, and the table 30 sucks and holds the 12-inch wafer W2 on the central suction area 300a. In addition, the suction force generated by the suction source 39 causes the second communication tube 32, the first chamber 41, the communication port 401 in the opened state, the second chamber 42, and the third communication tube 33 to be a suction source 39. As a flow of air is generated, the table 30 sucks and holds the 12-inch wafer W2 also on the outer peripheral suction area 300b.

  In the state before the suction source 39 is activated, the elastic member 45D has a natural length, and the communication port 401 is not closed by the valve 47. Therefore, when the suction source 39 is activated, the second communication tube 32 is formed. The suction path consisting of the third communication pipe 33 is immediately formed, there is no vacuum leak, and the 12-inch wafer W2 is suctioned and held on the central suction area 300a and the outer peripheral suction area 300b of the table 30. That is, although the inside of the third chamber 43 is also sucked via the fourth communication pipe 34, at the same time the suction path consisting of the second communication pipe 32 to the third communication pipe 33 is also sucked, so the valve The inside of the mechanism 4 and the insides of the first communication pipe 31 to the fourth communication pipe 34 are in a near vacuum state without the valve 47 being lowered. Therefore, since the internal pressure of each chamber is also in the equilibrium state, the valve 47 does not descend thereafter and the communication port 401 is not closed. Therefore, the table 30 has a 12-inch wafer in the central suction area 300a and the outer circumference suction area 300b. W2 can be reliably suctioned and held.

  For example, as shown in FIG. 11, the second outer peripheral suction area 300c (which is larger than the 12-inch wafer W2), which surrounds the outer peripheral suction area 300b with the partition portion 303 made of a non-air-permeable material in between. In the case of further including a region for sucking and holding the workpiece, the valve mechanism 4A is independently connected to the second outer peripheral suction region 300c. The valve mechanism 4A is configured in the same manner as the valve mechanism 4. In the valve mechanism 4A, the second communication pipe 32 communicates with the second outer peripheral suction area 300c, and the third communication pipe 33 joins the first communication pipe 31 and communicates with the suction source 39, The fourth communication pipe 34 joins the first communication pipe 31 and is in communication with the suction source 39.

As shown in FIG. 11, when the workpiece (for example, 12-inch wafer W2) is placed on the table 30 and suctioned and held while covering the central suction area 300a and the outer peripheral suction area 300b, the suction source 39 By operating, as in the case described earlier with reference to FIG. 7, the suction force is transmitted to the central suction area 300a via the first communication pipe 31, and the valve 47 of the valve mechanism 4 is lowered. As the communication port 401 is not closed, the internal pressure of each chamber is in equilibrium and the suction force is continuously transmitted to the outer peripheral suction area 300b. The vacuum leak from the second outer peripheral suction area 300c is prevented by the valve mechanism 4A. That is, since the third chamber 43 of the valve mechanism 4A is depressurized without flowing in new air (more negative pressure becomes stronger), the valve 47 is connected via the shaft 46 connected to the lid 44 which descends- The communication port 401 is pulled in the Z direction, and the communication port 401 is closed by the valve 47. As a result, the outside air can be prevented from entering the second chamber 42 from the second outer peripheral suction area 300c, and the pressure in the second chamber 42 is reduced (the negative pressure becomes stronger).
In this manner, the pressure in the third chamber 43 and the second chamber 42 is reduced, so that (Equation 1) described above is satisfied, and the forces in the valve mechanism 4A are in equilibrium, and the suction source 39 The table 30 continues to suction and hold the 12-inch wafer W2 reliably between the central suction area 300a and the outer peripheral suction area 300b without generating vacuum leak from the second outer peripheral suction area 300c until Can.

  When a workpiece having a diameter larger than the 12-inch wafer W2 is placed on the table 30 and held by suction while covering the central suction area 300a, the outer peripheral suction area 300b, and the second outer peripheral suction area 300c, After the suction force is transmitted to the central suction area 300a, the outer peripheral suction area 300b, and the second outer peripheral suction area 300c by the operation of the valve 39, the valve mechanism 4 and the valve mechanism 4A do not lower the respective valves 47. The internal pressure in each room is in equilibrium. Therefore, each valve 47 does not descend and the communication port 401 is not closed, and the table 30 is larger than the 12-inch wafer W2 in the central suction area 300a, the outer suction area 300b, and the second outer suction area 300c. The workpiece having the diameter can be reliably held by suction.

1: Grinding apparatus 10: Base 17: Column 18: Grinding water injection nozzle 19: Grinding water supply source 6: Grinding means 7: Grinding feeding means 3: Holding device
30: table 300: adsorption section 300a: central suction area 300b: outer peripheral suction area 301: frame 302: partition section 31: first communicating pipe 32: second communicating pipe 33: third communicating pipe 34: fourth Communication tube 39: suction source 390: open / close valve 4: valve mechanism 40: casing 400: partition plate 401: communication port 41: first chamber 412: cylindrical wall
42: second chamber 49: opening and closing means 43: third chamber 430: opening 44: lid 45: elastic member 46: shaft 47: valve 49D: opening and closing means W 1: 8 inch wafer W: 12 inch wafer

Claims (4)

A holding device capable of suctioning and holding workpieces of different sizes by switching a suction area.
A table having a central suction area and an outer peripheral suction area surrounding the central suction area, a suction source communicated with the central suction area via the first communication pipe, and a second communication pipe in the outer peripheral suction area And a valve mechanism that is connected via the valve to selectively communicate the peripheral suction area with the suction source,
The valve mechanism
A first chamber, a second chamber adjacent to the first chamber and in communication via a communication port, and opening / closing means for selectively opening / closing the communication port,
The opening and closing means is
A third chamber disposed in the first chamber and having an opening formed opposite to the communication port, and the third chamber while closing the opening and moving in a direction toward or away from the communication port A lid for changing the volume in the room, an elastic member having a force to move the lid in a direction toward the communication port, a shaft connected to the lid and penetrating the communication port, and mounted on the tip of the shaft And a valve positioned in the second chamber to selectively open and close the communication port,
The second chamber is connected to the suction source via a third communication tube, and the third chamber is connected to the suction source via a fourth communication tube and in communication with the outer peripheral suction area. The second communication tube is connected to the first chamber,
When the workpiece is placed covering the central suction area, the workpiece is sucked and held in the central suction area, the first chamber is opened to the outside air through the peripheral suction area, and is communicated with the suction source. The third chamber is depressurized to reduce its volume and the communication port is closed by the valve pulled toward the opening through the shaft and from the peripheral suction area to the second chamber When the workpiece is placed covering the central suction area and the outer peripheral suction area, the workpiece is sucked and held in the central suction area and the outer peripheral suction area is A holding device connected to the suction source via the second communication pipe, the first chamber, the communication port, the second chamber, and the third communication pipe, and held by suction. Let A be the cross-sectional area of the gap between the communication port and the shaft, B be the area obtained by removing the cross-sectional area of the shaft from the area of the lid, H be the air pressure in the first chamber, and the elastic member When the force for moving the lid of the above in the direction approaching the communication port is W,
The holding device according to claim 1, wherein B × H> A × H + W.   The holding device according to claim 1, wherein a cross sectional area in the third communication pipe is smaller than a cross sectional area in the fourth communication pipe.   The holding device according to claim 1, 2, or 3, wherein the valve mechanism is independently connected to the second outer peripheral suction area when it further includes a second outer peripheral suction area surrounding the outer peripheral suction area.

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