JP5643019B2 - Chuck table - Google Patents

Description

  The present invention relates to a chuck table that is provided in a processing apparatus such as a grinding apparatus for grinding a wafer such as a semiconductor wafer and holds the wafer.

  In a semiconductor device manufacturing process, a large number of rectangular areas are defined by dividing lines called streets arranged in a lattice pattern on the surface of a semiconductor wafer having a substantially disk shape, and ICs, LSIs, etc. are divided into the rectangular areas. Form the device. Individual devices are formed by dividing the semiconductor wafer on which a large number of devices are formed in this manner along the streets. In order to reduce the size and weight of a device, the semiconductor wafer is usually ground to the predetermined thickness by grinding the backside of the semiconductor wafer prior to cutting the semiconductor wafer along the street and dividing it into individual devices. ing.

  A grinding apparatus for grinding the back surface of a semiconductor wafer includes a chuck table for sucking and holding the wafer, and a grinding means for grinding the wafer sucked and held on the chuck table. Such a grinding apparatus is equipped with a chuck table configured to selectively process a wafer having a small diameter (for example, a diameter of 200 mm) and a wafer having a large diameter (for example, a diameter of 300 mm). There is. This chuck table has a circular first holding region for sucking and holding a small-diameter wafer, and an annular second holding member that surrounds the first holding region and sucks and holds the outer peripheral portion of the large-diameter wafer. A holding area is provided. The chuck table configured as described above has a configuration in which a negative pressure is applied only to the first holding region by controlling a suction unit that communicates the first holding region and the second holding region, and the first holding region. A mode in which a negative pressure is applied to the region and the second holding region is selected. (For example, refer to Patent Document 1.)

JP 2003-133392 A

Thus, although the diameter of the wafer is standardized, there is an error of several millimeters in the diameter depending on the ingot manufacturer, and the size of the suction holding portion for holding the wafer may not match the size of the wafer. If the suction holding part that holds the wafer is larger than the wafer, the grinding waste is sucked from the outer peripheral part of the suction holding part and the suction holding part is clogged. On the other hand, if the suction holding portion for holding the wafer is smaller than the wafer, the suction holding of the outer peripheral portion of the wafer becomes insufficient, and there is a problem that the wafer flutters during processing and chipping occurs.
Also, if the wafer is thinly ground, the chamfered portion formed on the outer periphery of the wafer becomes a knife edge, which is dangerous and chipping occurs. Therefore, a technique for removing the outer peripheral portion by 1 to 2 mm before grinding the wafer has been proposed. However, a similar problem occurs in this case.

  The present invention has been made in view of the above-mentioned facts, and its main technical problem is to provide a chuck table that can reliably suck and hold a wafer in a suction region even if there is an error of several millimeters in the diameter of the wafer. There is.

In order to solve the main technical problem, according to the present invention, a chuck table for holding a wafer,
Adsorption comprising a main suction holding member formed in a disk shape by a porous member and an annular auxiliary suction holding member arranged on the outer periphery of the suction holding member via a partition wall for adjusting an error in the size of the wafer Comprising a chuck and a frame having a circular fitting recess on the upper surface for fitting the suction chuck;
A main suction passage is provided at a position corresponding to the main suction holding member on the bottom wall forming the fitting recess of the frame, and opens to a position corresponding to the annular auxiliary suction holding member. And an auxiliary suction passage that opens on the lower surface .
The lower surface side of the auxiliary suction passage is configured so that a blind plug can be detachably mounted.
A chuck table is provided.

  A plurality of the annular auxiliary suction holding members are provided via the partition walls, and the auxiliary suction passages are provided corresponding to the plurality of annular auxiliary suction holding members, respectively.

A chuck table according to the present invention includes a main suction holding member formed in a disk shape, an annular auxiliary suction holding member disposed on the outer periphery of the suction holding member via a partition wall for adjusting an error in the size of the wafer, And a frame body having a circular fitting recess for fitting the suction chuck on the upper surface, and the bottom wall forming the fitting recess of the frame corresponds to the main suction holding member The main suction passage is provided at a position where the auxiliary suction passage is opened, and the auxiliary suction passage is provided at a position corresponding to the annular auxiliary suction holding member and at the lower surface. Since it is configured to be detachably mounted, the suction area in the suction chuck can be adjusted by blindly plugging the auxiliary suction passage. Therefore, by adjusting the suction area in the suction chuck constituting the chuck table corresponding to the size of the wafer, the wafer protrudes from the suction area in the suction chuck, or the outer periphery of the wafer is located inside the outer periphery of the suction area. There is nothing. For this reason, when the wafer protrudes from the suction region in the suction chuck, the suction holding of the outer peripheral portion of the wafer becomes insufficient, and the problem that the wafer flutters during processing and the chipping occurs can be solved. Further, since the outer periphery of the wafer is not positioned inside the outer periphery of the suction region in the suction chuck, the suction chuck does not suck clogging due to suction of the grinding waste.

The perspective view of the grinding device equipped with the chuck table comprised according to this invention. The perspective view of the chuck table mechanism provided with the chuck table constituted according to the present invention. The perspective view which decomposes | disassembles and shows the support base and chuck table which comprise the chuck table mechanism shown in FIG. The perspective view which decomposes | disassembles and shows the frame and suction chuck | zipper which comprise the chuck table shown in FIG. 1 is a cross-sectional view of a chuck table configured according to the present invention.

  Hereinafter, preferred embodiments of a chuck table configured according to the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 shows a perspective view of a grinding apparatus equipped with a chuck table constructed according to the present invention.
The grinding device in the illustrated embodiment includes a device housing 2 having a substantially rectangular parallelepiped shape. A stationary support plate 21 is erected on the upper right end of the device housing 2 in FIG. Two pairs of guide rails 22, 22 and 23, 23 extending in the vertical direction are provided on the inner surface of the stationary support plate 21. A rough grinding unit 3 as rough grinding means is mounted on one guide rail 22, 22 so as to be movable in the vertical direction, and a finish grinding unit 4 as finish grinding means is vertically mounted on the other guide rail 23, 23. It is mounted to move in the direction.

  The rough grinding unit 3 includes a unit housing 31, a rough grinding wheel 33 attached to a wheel mount 32 rotatably attached to the lower end of the unit housing 31, and a wheel mount 32 attached to the upper end of the unit housing 31. An electric motor 34 that rotates in a direction indicated by an arrow 32a and a moving base 35 on which the unit housing 31 is mounted are provided.

  The movable base 35 is provided with guided rails 351 and 351, and the guided rails 351 and 351 are movably fitted to the guide rails 22 and 22 provided on the stationary support plate 21. The rough grinding unit 3 is supported so as to be movable in the vertical direction. The rough grinding unit 3 in the form shown in the figure includes a grinding feed means 36 for moving the moving base 35 along the guide rails 22 and 22 to feed the grinding wheel 33 by grinding. The grinding feed means 36 includes a male screw rod 361 that is disposed on the stationary support plate 21 in parallel with the guide rails 22 and 22 and is rotatably supported, and a pulse motor 362 for rotationally driving the male screw rod 361. And a female screw block (not shown) that is mounted on the moving base 35 and is screwed with the male screw rod 361. By driving the male screw rod 361 forward and backward by a pulse motor 362, the rough grinding unit 3 is moved up and down. It is moved in the direction (direction perpendicular to the holding surface of the chuck table described later).

  The finish grinding unit 4 is also configured in the same manner as the rough grinding unit 3, and includes a unit housing 41, a grinding wheel 43 attached to a wheel mount 42 rotatably attached to the lower end of the unit housing 41, and the unit An electric motor 44 that is mounted on the upper end of the housing 41 and rotates the wheel mount 42 in the direction indicated by the arrow 42a, and a moving base 45 on which the unit housing 41 is mounted are provided.

  Guided rails 451 and 451 are provided on the moving base 45, and the guided rails 451 and 451 are movably fitted to the guide rails 23 and 23 provided on the stationary support plate 21. The finish grinding unit 4 is supported so as to be movable in the vertical direction. The finish grinding unit 4 in the illustrated form includes feed means 46 for moving the moving base 45 along the guide rails 23 and 23 and grinding and feeding the grinding wheel 43. The feed means 46 includes a male screw rod 461 that is disposed on the stationary support plate 21 in parallel with the guide rails 23 and 23 in a vertical direction and is rotatably supported, and a pulse motor 462 for rotationally driving the male screw rod 461. , A female screw block (not shown) mounted on the moving base 45 and screwed with the male screw rod 461 is provided, and the male screw rod 461 is driven forward and reverse by a pulse motor 462 to move the finish grinding unit 4 in the vertical direction. It is moved in a direction (perpendicular to the holding surface of the chuck table described later).

  The grinding apparatus in the illustrated embodiment includes a turntable 5 disposed so as to be substantially flush with the upper surface of the apparatus housing 2 on the front side of the stationary support plate 21. The turntable 5 is formed in a relatively large-diameter disk, and can be appropriately rotated in the direction indicated by the arrow 5a by a rotation mechanism (not shown). In the illustrated embodiment, three chuck table mechanisms 6 are arranged on the turntable 5 so as to be rotatable in a horizontal plane with a phase angle of 120 degrees. The three chuck table mechanisms 6 configured as described above are rotated in a direction indicated by an arrow 6a by a rotation driving means (not shown). The three chuck table mechanisms 6 disposed on the turntable 5 are configured so that the workpiece loading / unloading area A, the rough grinding area B, the finish grinding area C, and the work are processed by appropriately rotating the turntable 5. It is moved sequentially to the goods carry-in / out area A.

The chuck table mechanism 6 will be described with reference to FIGS.
The chuck table mechanism 6 in the illustrated embodiment includes a support base 61 and a chuck table 62 disposed on the upper surface of the support base 61 as shown in FIGS. 2 and 3. The support base 61 is made of a metal material such as stainless steel. As shown in FIG. 3, a circular recess 611 serving as a negative pressure chamber is formed on the upper surface, and an annular shape surrounding the circular recess 611. A support portion 612 is provided. A suction passage 614 is provided at the center of the bottom wall 613 forming the circular recess 611 serving as the negative pressure chamber, and the suction passage 614 is connected to suction means (not shown). Therefore, when a suction means (not shown) is operated, negative pressure is applied to the circular recess 611 serving as a negative pressure chamber via the suction passage 614. In addition, four auxiliary support portions 615 having the same height as the upper surface of the annular support portion 612 are provided around the suction passage 612 on the bottom wall 613 forming the circular recess 611. The annular support portion 612 has four female screw holes 616 formed therein.

  As shown in FIGS. 3 and 4, the chuck table 62 includes a disk-shaped suction chuck 63 and a circular frame body 64 that supports the suction chuck 63. The chucking chuck 63 constituting the chuck table 62 includes a main suction holding member 631 formed in a disk shape by a porous member such as a porous ceramic material, and a wafer size described later disposed on the outer periphery of the main suction holding member 631. And an annular auxiliary suction holding member 632 for adjusting the error. The diameter of the main suction holding member 631 constituting the suction chuck 63 is set to a value about 6 mm smaller than the diameter of the standardized wafer, that is, a value corresponding to the smallest diameter among the standardized wafers. The annular auxiliary suction holding member 632 constituting the suction chuck 63 is composed of three annular auxiliary suction holding members 632a, 632b, and 632c in the illustrated embodiment, and each is similar to the main suction holding member 631 and is a porous ceramic material. It is formed of a porous member such as. The three annular auxiliary suction holding members 632a, 632b, and 632c are each blocked from air permeability by a partition film 633 made of an adhesive. The three annular auxiliary suction holding members 632a, 632b, 632c are set to have a width of 2 to 3 mm. The suction chuck 63 configured as described above is attached to the frame body 64 with an outer peripheral surface (the outer peripheral surface of the annular auxiliary suction holding member 632c) and a part of the lower surface through a bonding agent.

  The frame body 64 constituting the chuck table 62 is formed in a circular shape by a metal material such as stainless steel, and as shown in FIG. 4, a circular fitting recess 641 into which the suction chuck 63 is fitted is formed on the upper surface. An annular attachment portion 642 that is formed and surrounds the circular fitting recess 641 is provided. The outer diameter of the frame body 64 is formed to be the same as the outer diameter of the support base 61, and the inner diameter of the circular fitting recess 641 is the same as that of the circular recess 611 provided in the support base 61. It is formed the same as the inner diameter. As shown in FIGS. 4 and 5 (a), (b), and (c), the suction chuck 63 is formed on the bottom wall 643 that forms the circular fitting recess 641 of the frame body 64 formed in this way. A plurality of main suction passages 644 that open to positions corresponding to the main suction holding members 631 in the fitted state are provided, and open to positions corresponding to the annular auxiliary suction holding members 632a, 632b, and 632c, respectively. Auxiliary suction passages 645a, 645b, 645c are provided. The auxiliary suction passages 645a, 645b, 645c are formed with internal threads, and circular recesses 646a, 646b, 646c are formed on the lower surface side to surround the auxiliary suction passages 645a, 645b, 645c, respectively. The auxiliary suction passages 645a, 645b, and 645c formed in this manner are detachably mounted with bolts 65 serving as blind plugs. The circular recesses 646a, 646b, and 646c are set to a size that can accommodate the head of the bolt 65 serving as a blind plug. Accordingly, when the bolt 65 is screwed into the female screw formed in the auxiliary suction passages 645a, 645b, 645c, the head is accommodated in the circular recesses 646a, 646b, 646c. In addition, it is desirable to attach the seal 650 to the bolt 65 that becomes a blind plug.

  For example, if a bolt 65 that becomes a blind plug is attached to any of the auxiliary suction passages 645a, 645b, and 645c, the communication of the auxiliary suction passages 645a, 645b, and 645c is blocked, and the annular auxiliary suction holding members 632a, 632b, and 632c are connected. There is no negative pressure. Therefore, the main suction holding member 631 is the only suction area where negative pressure acts on the suction chuck 63. If bolts 65 that are blind plugs are attached to the auxiliary suction passages 645c and 645b, the communication between the auxiliary suction passages 645c and 645b is cut off, and a negative pressure is applied to the annular auxiliary suction holding member 632a via the auxiliary suction passage 645a. can do. In this case, the suction areas where negative pressure acts on the suction chuck 63 are the main suction holding member 631 and the annular auxiliary suction holding member 632a. Further, if a bolt 65 serving as a blind plug is attached to the auxiliary suction passage 645c, the communication of the auxiliary suction passage 645c is blocked and negative pressure is applied to the annular auxiliary suction holding members 632a and 632b via the auxiliary suction passages 645a and 645b. can do. In this case, the suction areas where negative pressure acts on the suction chuck 63 are the main suction holding member 631 and the annular auxiliary suction holding members 632a and 632b. On the other hand, if bolts 65 that are blind plugs are not attached to any of the auxiliary suction passages 645a, 645b, 645c, the auxiliary suction passage holding members 632a, 632b, 632c are connected to the annular auxiliary suction holding members 632a, 632b, 632c via the auxiliary suction passages 645a, 645b, 645c. Negative pressure can be applied. Accordingly, the suction areas where negative pressure acts on the suction chuck 63 are the main suction holding member 631 and the annular auxiliary suction holding members 632a, 632b, and 632c.

  The annular mounting portion 642 of the frame body 64 configured as described above corresponds to the four female screw holes 616 provided in the annular support portion 612 of the support base 61 as shown in FIGS. 3 and 4. Four bolt insertion holes 647 are formed at the positions. Then, the fastening bolts 66 are inserted into the four bolt insertion holes 647 and screwed into the four female screw holes 616 provided in the annular support portion 612 of the support base 61, thereby supporting as shown in FIG. A chuck table 62 is mounted on the upper surface of the base 61. The chuck table 62 mounted on the upper surface of the support base 61 in this way has a plurality of main suction passages 644 and blind plugs provided in the bottom wall 643 forming the circular fitting recess 641 of the frame body 64. The auxiliary suction passages 645 a, 645 b, 645 c to which the bolt 65 is not attached are communicated with a circular concave portion 611 serving as a negative pressure chamber provided on the upper surface of the support base 61. Therefore, by operating a suction means (not shown), a negative pressure is applied to the suction area set as described above.

  Referring back to FIG. 1, the illustrated grinding apparatus is arranged on the one side with respect to the workpiece loading / unloading area A and stocks a semiconductor wafer that is a workpiece before grinding. A cassette 7, a second cassette 8 that is disposed on the other side with respect to the workpiece loading / unloading area A and stocks a semiconductor wafer that is a workpiece after grinding, and the first cassette 7 and the workpiece Centering means 9 that is disposed between the workpiece loading / unloading area A and performs centering of the workpiece, and a spinner disposed between the workpiece loading / unloading area A and the second cassette 8. The cleaning means 11 and the semiconductor wafer, which is a workpiece stored in the first cassette 7, are carried out to the centering means 9 and the semiconductor wafer cleaned by the spinner cleaning means 11 is transferred to the second cassette 8. A workpiece conveying means 12; Workpiece carry-in means 13 for carrying the semiconductor wafer placed on the centering means 9 and centered on the chuck table 62 of the chuck table mechanism 6 positioned in the work-piece carrying-in / out area A; A workpiece unloading means 14 for conveying the ground semiconductor wafer mounted on the chuck table 62 of the chuck table mechanism 6 positioned in the object loading / unloading area A to the spinner cleaning means 11 is provided. . Note that a plurality of sheets are accommodated in the first cassette 7 with the protective tape T adhered to the surface of the semiconductor wafer W. At this time, the semiconductor wafer W is accommodated with the back surface facing upward.

The grinding apparatus in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
When grinding the semiconductor wafer W before grinding which is accommodated in the cassette 7, the size of the semiconductor wafer W accommodated in the cassette 7 is confirmed, and the chuck table 62 is configured corresponding to the size of the semiconductor wafer W. The suction area in the suction chuck 63 to be set is set, and the position where the auxiliary suction passages 645a, 645b, 645c formed in the frame body 64 constituting the chuck table 62 are blocked as described above is selected, and the selected auxiliary is selected. A bolt 65 serving as a blind plug is attached to the suction passage. The rods of the semiconductor wafer W housed in the cassette 7 are formed with the same diameter.

  As described above, if the suction area in the suction chuck 63 constituting the chuck table 62 is set in accordance with the size of the semiconductor wafer W before grinding, which is accommodated in the cassette 7, the workpiece transfer means 12 is first moved. The semiconductor wafer W before the grinding process which is operated and accommodated in the cassette 7 is conveyed to the centering means 9. The semiconductor wafer W conveyed to the centering means 9 is centered here. The semiconductor wafer W centered by the centering means 9 is attached to the chuck table 62 of the chuck table mechanism 6 positioned in the workpiece loading / unloading area A by the turning operation of the workpiece loading means 13. Placed on top. Then, the semiconductor wafer W is sucked and held on the suction chuck 63 via the protective tape T by operating a suction means (not shown). At this time, since the suction area in the suction chuck 63 constituting the chuck table 62 is set corresponding to the size of the semiconductor wafer W, the semiconductor wafer W protrudes from the suction area in the suction chuck 63, or the semiconductor wafer W The outer periphery is not located inside the outer periphery of the suction region. When the semiconductor wafer W is sucked and held on the suction chuck 63 in this way, the turntable 5 is rotated 120 degrees in the direction indicated by the arrow 5a by a rotation drive mechanism (not shown) to place the semiconductor wafer W. The chuck table 6 is positioned in the rough grinding zone B.

  When the chuck table 6 holding the semiconductor wafer W by suction is positioned in the rough grinding area B, the chuck table 6 is rotated in a direction indicated by an arrow 6a by a rotation driving mechanism (not shown). On the other hand, the grinding wheel 33 of the rough grinding unit 3 is lowered by a predetermined amount by the grinding feed means 36 while being rotated in the direction indicated by the arrow 32a. As a result, rough grinding is performed on the back surface (upper surface) of the semiconductor wafer W on the chuck table 62. At this time, as described above, the semiconductor wafer W is sucked and held in the suction region set so as not to protrude from the suction region in the suction chuck 63 constituting the chuck table 62 or the outer periphery is located inside the outer periphery of the suction region. Therefore, the occurrence of chipping can be prevented without occurrence of fluttering, and the suction chuck 63 sucks the grinding waste and does not clog. During this time, the semiconductor wafer W before grinding is placed on the chuck table 62 of the next chuck table mechanism 6 positioned in the workpiece loading / unloading area A as described above. The semiconductor wafer W placed on the chuck table 62 is sucked and held on the chuck table 62 by operating a suction means (not shown). Next, the turntable 5 is rotated 120 degrees in the direction indicated by the arrow 5a, and the chuck table 62 holding the semiconductor wafer W that has been subjected to rough grinding is positioned in the finish grinding region C, and the semiconductor before grinding is performed. The chuck table 62 holding the wafer W is positioned in the rough grinding area B.

  In this way, the rough grinding unit 3 performs the rough grinding on the back surface (upper surface) of the semiconductor wafer W before the rough grinding, which is held on the chuck table 62 positioned in the rough grinding region B, and finishes. The back surface (upper surface) of the semiconductor wafer W held on the chuck table 62 positioned in the grinding region C and roughly ground is subjected to finish grinding by the finish grinding unit 4. Also in this finish grinding, the semiconductor wafer W is sucked into the suction region set without protruding from the suction region in the suction chuck 63 constituting the chuck table 62 or the outer periphery being located inside the outer periphery of the suction region as described above. Since it is held, it is possible to prevent the occurrence of chipping without occurrence of flickering, and the suction chuck 63 does not suck clogging due to suction of the grinding waste. Next, the turntable 5 is rotated 120 degrees in the direction indicated by the arrow 5a, and the chuck table 62 holding the semiconductor wafer W subjected to finish grinding is positioned in the workpiece loading / unloading area A. The chuck table 62 holding the semiconductor wafer W that has been subjected to rough grinding in the rough grinding area B is held in the finish grinding area C, and the chuck that holds the semiconductor wafer W before grinding in the work-in / out area A. The table 62 is moved to the rough grinding area B, respectively.

  As described above, the chuck table 62 that has returned to the work-in / out area A via the rough grinding area B and the finish grinding area C holds the semiconductor wafer W that has been subjected to the finish grinding here by suction. To release. Next, the workpiece unloading means 14 is operated, and the ground semiconductor wafer W placed on the chuck table 62 positioned in the workpiece loading / unloading area A is conveyed to the spinner cleaning means 11. . The semiconductor wafer W conveyed to the spinner cleaning means 11 is spin-dried while the grinding waste is cleaned and removed here. The semiconductor wafer W thus cleaned and spin-dried is transported and stored in the second cassette 8 by the workpiece transport means 12.

2: equipment housing 3: rough grinding unit 33: rough grinding wheel 36: grinding feed means 4: finish grinding unit 43: finish grinding wheel 46: grinding feed means 5: turntable 6: chuck table mechanism 61: support base 62: chuck Table 63: Suction chuck 631: Main suction holding member 632: Auxiliary suction holding member 64: Chuck table frame 645a, 645b, 645c: Auxiliary suction passage 65: Bolt that becomes a blind plug 7: First cassette 8: Second 9: Centering means 11: Spinner cleaning means 12: Workpiece conveying means 13: Workpiece carrying means 14: Workpiece carrying means
W: Semiconductor wafer
T: Protective tape

Claims (2)

A chuck table for holding a wafer,
Adsorption comprising a main suction holding member formed in a disk shape by a porous member and an annular auxiliary suction holding member arranged on the outer periphery of the suction holding member via a partition wall for adjusting an error in the size of the wafer Comprising a chuck and a frame having a circular fitting recess on the upper surface for fitting the suction chuck;
A main suction passage is provided at a position corresponding to the main suction holding member on the bottom wall forming the fitting recess of the frame, and opens to a position corresponding to the annular auxiliary suction holding member. And an auxiliary suction passage that opens on the lower surface .
The lower surface side of the auxiliary suction passage is configured so that a blind plug can be detachably mounted.
A chuck table characterized by that.   2. The chuck table according to claim 1, wherein a plurality of the annular auxiliary suction holding members are provided via partition walls, and the auxiliary suction passages are respectively provided corresponding to the plurality of annular auxiliary suction holding members.

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