Processing equipment

Abstract

To solve a problem in which shapes of frame bodies constituting a chuck table are not constant.SOLUTION: A chuck table 32 is configured to comprise: a porous plate 321 comprising an adsorption surface 321a for adsorbing a wafer; a frame body 320 surrounding surfaces other than the adsorption surface 321a; a cooling water passage 323b, formed inside the frame body 320, through which cooling water is flown; a wafer suction hole 322c, formed in the frame body 320, through which suction force is transmitted to the adsorption surface 321a of the porous plate 321; and bolt holes 322e and 323f, formed in the frame body 320, through which the chuck table 32 is fixed to a table base 34. The table base 34 comprises: a placement surface 341 on which a lower surface 323g side of the frame body 320 is placed; a frame body suction hole 342, formed on the placement surface 341, through which the frame body 320 is suctioned to be pulled; and a cooling water supply hole 343, communicating with the cooling water passage 323b, through which cooling water is supplied to the cooling water passage 323b.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a processing apparatus including at least a holding means for suction-holding a wafer, a processing means having a rotatable grinding wheel for grinding the wafer held by the holding means, and a processing liquid supplying means for supplying a processing liquid to the wafer. [Background technology]

[0002] A wafer has a number of devices such as ICs and LSIs formed on its surface along dividing lines, and the back surface is ground to the desired thickness. The wafer is then divided into individual device chips using a dicing machine and laser processing machine. These are then used in electrical devices such as mobile phones and personal computers.

[0003] The grinding apparatus at least comprises a holding means for suction-holding the wafer, a processing means having a rotatable grinding wheel with annular grinding stones for grinding the wafer held by the holding means, and a processing fluid supplying means for supplying grinding water as a processing fluid to the wafer, and can process the wafer to the desired thickness (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-153090 A Summary of the Invention [Problem to be solved by the invention]

[0005] In addition, in the processing device disclosed in the above Patent Document 1, free abrasive grains are supplied to the back surface of the wafer as a processing liquid, and the back surface of the wafer can be processed to a mirror surface by a polishing pad. The holding means for suction-holding the wafer includes a chuck table for holding the wafer and a table base for detachably supporting the chuck table, and the chuck table includes a porous plate having an adsorption surface for adsorbing the wafer, a frame surrounding the surface other than the adsorption surface, wafer suction holes formed in the bottom surface of the frame for transmitting suction force to the adsorption surface of the porous plate, and bolt holes formed in the frame for fixing to the table base, so that the wafer can be suction-held.

[0006] When processing a wafer using the above-mentioned processing apparatus, the holding surface of the chuck table is ground in advance by a grinding means of a grinding apparatus so that the shape of the holding surface of the chuck table and the shape of the ground surface of the wafer placed and held on the chuck table become the same, thereby making the thickness of the wafer uniform throughout its entire area.

[0007] However, even if the holding surface of the chuck table is adjusted as described above and the wafer is ground or polished, it has been found that minute thickness variations (for example, about 2 to 3 μm) occur when the wafer thickness after processing is measured. Such minute variations can become a major problem when wafer thicknesses become extremely thin as in recent years.

[0008] As a result of thorough investigation into the above-mentioned problems, the applicant has found that in conventional grinding devices, the shape of the frame constituting the chuck table is not consistent when the holding surface of the chuck table is ground and when a wafer is held by suction to the holding surface of the chuck table and processed thereon, resulting in variations in the thickness of the wafer.

[0009] The present invention has been made in consideration of the above-mentioned facts, and its main technical object is to provide a processing apparatus that can solve the problem that the shape of the frame that constitutes the chuck table is not constant when the holding surface of the chuck table is ground and when a wafer is held by suction to the holding surface of the chuck table for processing. [Means for solving the problem]

[0010] In order to solve the above-mentioned main technical problem, according to the present invention, there is provided a processing apparatus including at least a holding means for suction-holding a wafer, a processing means having a rotatable grinding wheel for grinding the wafer held by the holding means, and a processing liquid supplying means for supplying a processing liquid to the wafer, wherein the holding means includes a chuck table for holding the wafer, and a table base for detachably supporting the chuck table, and the chuck table includes a porous plate having an adsorption surface for adsorbing the wafer, the table base includes a mounting surface on which the lower surface of the frame is placed, a frame suction hole formed on the mounting surface for attracting the frame by suction, and a cooling water supply hole communicated with the cooling water passage and supplying cooling water to the cooling water passage. The wafer suction holes are formed on the plate mounting surface of the frame on which the porous plate is mounted, and the mounting surface of the table base is provided with communication holes which communicate with the wafer suction holes and transmit suction force independently of the frame suction holes. A processing apparatus is provided.

[0011] According to the present invention, there is provided a processing apparatus including at least a holding means for suction-holding a wafer, a processing means having a rotatable grinding wheel for grinding the wafer held by the holding means, and a processing liquid supplying means for supplying a processing liquid to the wafer, the holding means including a chuck table for holding the wafer, and a table base for detachably supporting the chuck table, the chuck table including a porous plate having an adsorption surface for adsorbing the wafer, and a surface other than the adsorption surface. a cooling water passage formed inside the frame for distributing cooling water, a wafer suction hole formed in the frame for transmitting a suction force to an adsorption surface of the porous plate, and a bolt hole formed in the frame for fixing the chuck table to the table base, the table base having a mounting surface on which the lower surface of the frame is placed, a frame suction hole formed in the mounting surface for attracting the frame by suction, and a cooling water supply hole connected to the cooling water passage for supplying cooling water to the cooling water passage, The wafer suction holes are formed on the side surface of the frame, and a communication hole for transmitting a suction force is formed on the side surface of the table base independently of the frame suction holes. Processing equipment is provided . Effect of the Invention

[0012] The processing apparatus of the present invention is a processing apparatus including at least a holding means for suction-holding a wafer, a processing means having a rotatable grinding wheel for grinding the wafer held by the holding means, and a processing liquid supplying means for supplying a processing liquid to the wafer, the holding means including a chuck table for holding the wafer, and a table base for detachably supporting the chuck table, the chuck table including a porous plate having an adsorption surface for adsorbing the wafer, and a surface other than the adsorption surface. the table base includes a mounting surface on which the lower surface of the frame is placed, a frame suction hole formed on the mounting surface for attracting the frame by suction, and a cooling water supply hole communicated with the cooling water passage and supplying cooling water to the cooling water passage. The wafer suction holes are formed on the plate mounting surface of the frame on which the porous plate is mounted, and the mounting surface of the table base is provided with communication holes which communicate with the wafer suction holes and transmit suction force independently of the frame suction holes. Therefore, when grinding the adsorption surface of the porous plate of the chuck table and when grinding a wafer, the entire frame of the chuck table is securely fixed onto the table base and is maintained at a predetermined temperature by cooling water while grinding is performed by the grinding means, so that the shape of the holding surface of the chuck table, i.e., the adsorption surface of the porous plate, matches the shape of the grinding surface of the wafer, thereby suppressing the occurrence of variations in wafer thickness after grinding. The processing apparatus of the present invention is a processing apparatus comprising at least a holding means for suction-holding a wafer, a processing means provided with a rotatable grinding wheel for grinding the wafer held by the holding means, and a processing liquid supplying means for supplying a processing liquid to the wafer, the holding means including a chuck table for holding the wafer, and a table base for detachably supporting the chuck table, the chuck table including a porous plate having an adsorption surface for adsorbing the wafer, a frame surrounding the chuck table except for the adsorption surface, cooling water channels formed inside the frame for distributing cooling water, wafer suction holes formed in the frame for transmitting suction force to the adsorption surface of the porous plate, and bolt holes formed in the frame for fixing the chuck table to the table base, the table base including a lower surface of the frame, a porous plate having an adsorption surface for adsorbing the wafer, a frame surrounding the porous plate except for the adsorption surface, a cooling water channel formed inside the frame for distributing cooling water, a wafer suction hole formed in the frame for transmitting suction force to the adsorption surface of the porous plate, and a bolt hole formed in the frame for fixing the chuck table to the table base, and a cooling water supply hole which is connected to the cooling water passage and supplies cooling water to the cooling water passage, and the wafer suction hole is formed on the side of the frame, and a communicating hole which transmits suction force independently of the frame suction hole is formed on the side of the table base. Therefore, both when grinding the adsorption surface of the porous plate of the chuck table and when grinding a wafer, the entire area of ​​the frame of the chuck table is securely fixed to the table base and grinding is performed by the grinding means while being maintained at a predetermined temperature by the cooling water, and the shape of the holding surface of the chuck table, i.e., the adsorption surface of the porous plate, matches the shape of the grinding surface of the wafer, thereby suppressing the occurrence of variations in thickness of the wafer after grinding. [Brief description of the drawings]

[0013] [Figure 1] 1 is an overall perspective view of a grinding device according to a first embodiment; [Diagram 2] 2 is a perspective view of a chuck table and a table base that constitute a holding means of the grinding apparatus shown in FIG. 1, and an exploded perspective view of the chuck table. FIG. [Diagram 3] 3 is a plan view of a lower frame constituting the holding means shown in FIG. 2. [Figure 4] FIG. 2(a) is a perspective view of a holding means attached to the grinding apparatus of FIG. 1, and FIG. 2(b) is a schematic partial cross-sectional view of the holding means shown in FIG. [Diagram 5] FIG. 11 is a perspective view showing a mode of grinding the suction surface of the holding means. [Figure 6] 2 is a perspective view showing a manner in which the back surface of a wafer is ground by the grinding apparatus shown in FIG. 1. [Figure 7] 13 is a perspective view of a chuck table and a table base constituting a holding means of a second embodiment, and an exploded perspective view of the chuck table. FIG. [Figure 8] FIG. 8(a) is a perspective view of the holding means shown in FIG. 7, and FIG. 8(b) is a schematic partial cross-sectional view of the holding means shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a processing device configured based on the present invention will be described in detail with reference to the accompanying drawings.

[0015] Fig. 1 shows an overall perspective view of a grinding apparatus 1 exemplified as a first embodiment of a processing apparatus configured based on the present invention. The grinding apparatus 1 shown in Fig. 1 includes a holding means 3 for suction-holding a plate-shaped wafer 10, which is a workpiece of this embodiment, a grinding means 4 as a processing means for grinding the holding means 3 and the wafer 10 held by the holding means 3, and a processing liquid supplying means 5 for supplying a processing liquid to the wafer 10.

[0016] The grinding device 1 includes a device housing 2. The device housing 2 includes a body portion 21 having a substantially rectangular parallelepiped shape, and an upright wall 22 that is provided at the rear end portion of the body portion 21 and stands upright in the vertical direction.

[0017] The holding means 3 is disposed in a main body 21, and bellows means 6a, 6b are disposed on both sides of the holding means 3 in the X-axis direction indicated by the arrow X. A moving means (not shown) for moving the holding means 3 in the X-axis direction is housed inside the main body 21. By operating the moving means, the bellows means 6a, 6b can be contracted and extended, and the holding means 3 can be moved between a carry-in / out area at the front side in the figure where the unprocessed wafer 10 is placed on the chuck table 32, and a processing area at the back side in the figure where processing is performed directly below the grinding means 4.

[0018] The holding means 3 of this embodiment will be described in more detail with reference to Fig. 2. The holding means 3 includes at least a chuck table 32 and a table base 34 that detachably supports the chuck table 32. As shown exploded on the right side of the figure, the chuck table 32 includes a porous plate 321 having an adsorption surface 321a that adsorbs the wafer 10, and a frame 320 that surrounds the porous plate 321 except for the adsorption surface 321a, i.e., the side surface 321b and the back surface 321c opposite to the adsorption surface 321a. As shown in the figure, the frame 320 is disassembled into an upper frame 322 and a lower frame 323. The upper frame 322 includes a frame upper surface 322a, a side wall 322h constituting a side surface, a plate mounting surface 322b on which the back surface 321c of the porous plate 321 is placed, a plurality of wafer suction holes 322c (two in this embodiment) formed to penetrate the plate mounting surface 322b and the lower surface 322g and transmit a suction force (negative pressure) to the adsorption surface 321a of the porous plate 321, an outer peripheral step portion 322d formed along the side wall 322h, and a plurality of bolt holes 322e formed in the outer peripheral step portion 322d for fixing the frame 320 to the table base 34. The plurality of wafer suction holes 322c opening in the plate mounting surface 322b are connected by an annular groove 322f. In this embodiment, four bolt holes 322e (only three are shown in FIG. 2) are formed at equal intervals in the outer peripheral step portion 322d. The lower surface 322g of the upper frame 322 is a flat surface except for the region in which the wafer suction holes 322c are formed.

[0019] A cooling water passage 323b formed from a recess having a predetermined depth is formed on the surface 323a of the lower frame 323. A plurality of cooling water supply holes 323c (two in this embodiment) are formed in a predetermined area on the center side of the lower frame 323, which penetrate vertically and supply cooling water from a cooling water supply source (not shown) to the cooling water passage 323b. Also, a through hole 323e that penetrates vertically and transmits negative pressure is formed in a region of the surface 323a of the lower frame 323 where the cooling water passage 323b is not formed, and at a position corresponding to the wafer suction hole 322c of the upper frame 322. Also, a bolt hole 323f is formed in the outer peripheral region of the lower frame 323 at a position corresponding to the bolt hole 322e formed in the upper frame 322. A lower surface 323g of the lower frame 323 is formed as a flat surface except for the region where the cooling water supply hole 323c and the through hole 323e are formed. By combining the upper frame 322 and the lower frame 323 together, a cooling water passage 323b is formed inside the frame 320, and a cooling water outlet hole 323d is formed at the outer peripheral end of the cooling water passage 323b. The porous plate 321 of this embodiment is formed from, for example, porous ceramics having air permeability, but it can also be formed from other grindable and air permeable materials, such as an aggregate of pumice, resin or metal granules, and is not particularly limited.

[0020] 2, the table base 34 is at least composed of a mounting surface 341 on which the frame 320 is mounted, a frame suction hole 342 formed on the mounting surface 341 and transmitting a negative pressure for sucking the lower surface 323g of the lower frame 323 constituting the frame 320 from a suction source (not shown), a cooling water supply hole 343 for supplying cooling water to the cooling water supply hole 323c of the lower frame 323, and a first communication hole 344 that is connected to the wafer suction hole 322c formed in the upper frame 322 of the chuck table 32 and is connected to a suction source (not shown) through a path independent of the frame suction hole 342. In this embodiment, the mounting surface 341 is formed with an expanded diameter portion 342a surrounding the frame suction hole 342, an annular groove 343a connecting the multiple cooling water supply holes 343, and an annular groove 344a connecting the multiple first communication holes 344.

[0021] As shown in the figure, the frame suction hole 342 in this embodiment is formed in the central region of the support surface 341 of the table base 34, and bolt fastening holes 345 are formed on the outer peripheral edge of the support surface 341 of the table base 34 at positions corresponding to the bolt holes 322e of the upper frame 322 and the bolt holes 323f of the lower frame 323 of the chuck table 32 described above.

[0022] 3 shows a plan view of the lower frame 323. As can be seen from the figure, the cooling water passage 323b is formed over the entire surface 323a of the lower frame 323, and the cooling water supplied through the cooling water supply hole 343 of the table base 34 and the cooling water supply hole 323c of the lower frame 323 is spread over the entire interior of the frame 320 and discharged from the cooling water outlet hole 323d. In this embodiment, the frame 320 is divided into the upper frame 322 and the lower frame 323, but the present invention is not limited to this, and the frame 320 may be integrally molded to form the cooling water passage inside the frame 320.

[0023] The chuck table 32 and the table base 34 are integrated together by inserting fastening bolts 8 through bolt holes 322e, 323f formed in the frame 320 of the chuck table 32 and fastening them to bolt fastening holes 345 of the table base 34.

[0024] Fig. 4(a) shows a perspective view of the holding means 3 (see Fig. 2) in which the chuck table 32 is placed on the table base 34 and integrated with the holding means 3 by bolts 8, and Fig. 4(b) shows a partial schematic cross-sectional view for explaining the internal structure of the holding means 3 shown in Fig. 4(a). Note that Fig. 4(b) is not an actual cross-sectional view of the holding means 3 shown in Fig. 4(a), but shows a number of paths that actually appear in different cross sections for convenience of explanation.

[0025] 4(b), the table base 34 includes a first suction path 346 for transmitting a suction force to a frame suction hole 342 formed in a mounting surface 341 on which the frame 320 is mounted, and by operating a suction source (not shown), even when the wafer 10 is not held by the holding means 3, a first suction force (negative pressure) Vm1 can be applied to a lower surface 323g of the lower frame 323 constituting the frame 320 of the holding means 3 to suck the lower frame 323. In addition, if the wafer 10 is mounted on the adsorption surface 321a of the porous plate 321 and held by suction, the second suction force (negative pressure) Vm2 can be transmitted to the adsorption surface 321a of the porous plate 321 via the first communication hole 344 formed in the table base 34, the through hole 323e of the lower frame 323, and the wafer suction hole 322c of the upper frame 322 described above, to hold the wafer 10 by suction. The frame suction hole 342 and the first communication hole 344 are connected to a suction source (not shown) by independent suction paths, so that even when the wafer 10 is not held by suction on the chuck table 32, only the frame 320 can be attracted to the table base 34 and held by suction.

[0026] 1 to continue the explanation, the grinding means 4 is disposed on the front surface of the upright wall 22. The grinding means 4 includes a movable base 41 and a spindle unit 42 mounted on the movable base 41. The movable base 41 is engaged at its rear surface side with a pair of guide rails 221, 221 disposed on the upright wall 22 of the device housing 2, and is mounted so as to be slidable in the Z-axis direction (up and down direction) relative to the guide rails 221, 221.

[0027] The spindle unit 42 includes a spindle housing 421 supported by a support portion 413 formed integrally with the movable base 41, a rotating spindle 422 rotatably held by the spindle housing 421, and a servo motor 423 disposed as a rotation drive means for rotating the rotating spindle 422. The lower end of the rotating spindle 422 protrudes from the lower end side of the spindle housing 421, and a mounter 424 is provided at the lower end. A grinding wheel 425 is attached to the lower surface of the mounter 424, and a plurality of grinding stones 426 are disposed in an annular shape on the lower surface of the grinding wheel 425 (also see FIG. 5).

[0028] The grinding device 1 shown in FIG. 1 includes a grinding feed means 7 that moves the grinding means 4 in the vertical direction (the direction perpendicular to the holding surface of the chuck table described later) along the pair of guide rails 221, 221. The grinding feed means 7 includes a male screw rod 71 that is disposed on the front side of the upright wall 22 and extends in the vertical direction. The male screw rod 71 is rotatably supported at its upper and lower ends by the upright wall 22. A pulse motor 72 is disposed at the upper end of the male screw rod 71 as a drive source for rotating the male screw rod 71, and the output shaft of the pulse motor 72 is connected to the male screw rod 71. A screw connection portion (not shown) is formed on the rear surface of the moving base 41, and a female screw hole extending in the vertical direction is formed in the connection portion, into which the male screw rod 71 is screwed. Such grinding feed means 7 can lower the grinding means 4 together with the movable base 41 by rotating the pulse motor 72 in the forward direction, and can raise the grinding means 4 together with the movable base 41 by rotating the pulse motor 74 in the reverse direction.

[0029] The grinding apparatus 1 is provided with machining fluid supply means 5 for supplying machining fluid L, such as grinding water, to the workpiece being ground on the holding means 3. The machining fluid supply means 5 is provided with a machining fluid tank 51 for storing the machining fluid L and equipped with a pressure pump, a machining fluid supply path 52 connecting the machining fluid tank 51 and the grinding means 4, and an opening / closing valve 53 arranged on the machining fluid supply path 52 for opening and closing the machining fluid supply path 52. By operating the pressure pump of the machining fluid tank 51 and opening the opening / closing valve 53, the machining fluid L can be supplied to the machining area via the grinding means 4.

[0030] The grinding device 1 of this embodiment has a configuration generally as described above, and its functions and actions will be described below.

[0031] As described above, when grinding the wafer 10 in the grinding apparatus 1, the holding surface of the chuck table 32, i.e., the suction surface 321a of the porous plate 321, is ground by the grinding means 4 before processing the wafer 10, as shown in FIG. 5. When performing the grinding, first, as described based on FIG. 4(b), a suction source (not shown) is operated to apply a first suction force (negative pressure) Vm1 to the lower surface 323g of the lower frame 323 constituting the frame 320, thereby sucking and attracting the frame 320. At this time, since the wafer 10 is not placed on the suction surface 321a of the chuck table 32, it is not necessary to transmit the second suction force (negative pressure) Vm2 via the first communication hole 344 formed in the table base 34, and the wafer suction hole 322c and through hole 323e of the frame 320.

[0032] Next, the moving means (not shown) is operated to position the chuck table 32 in the processing area below the grinding means 4, that is, at a position where the center of rotation of the chuck table 32 passes through the grinding wheel 426 of the grinding means 4, as shown in FIG. 5. Next, the rotating spindle 422 of the grinding means 4 is rotated at a predetermined rotation speed (e.g., 4000 rpm) in the direction indicated by the arrow R1, and the rotation drive means (not shown) is operated to rotate the chuck table 32 at a predetermined rotation speed (e.g., 300 rpm) in the direction indicated by the arrow R2. At this time, the cooling water supply source is operated to supply cooling water W to the cooling water passage 323b formed inside the frame body 320 through the cooling water supply hole 343 of the table base 34.

[0033] Next, the grinding feed means 7 is operated to lower the grinding means 4 in the direction indicated by the arrow R3, and while supplying the above-mentioned machining fluid L (grinding water) to the suction surface 321a of the chuck table 32, the grinding stone 426 arranged on the lower surface of the grinding wheel 425 is brought into contact with the porous plate 321 of the chuck table 32, and the suction surface 321a of the porous plate 321 is ground at a predetermined lowering speed (for example, 0.1 μm / sec). During the grinding, the operation of the cooling water supply source is continued, and the cooling water W flows through the cooling water passage 323b formed inside the frame 320 and is discharged from the cooling water jet hole 323d, and the frame 320 is cooled to a predetermined temperature. Then, when grinding is performed for a predetermined time or a predetermined amount, and the holding surface of the chuck table 32, i.e., the suction surface 321a of the porous plate 321 and the frame upper surface 322a of the upper frame 322, are ground to a flat surface, the grinding feed means 7 is stopped, and then, by performing an idle operation for a predetermined time, the grinding process is completed. The supply of the processing liquid L to the holding surface of the chuck table 32 is performed by using the above-mentioned processing liquid supply means 5, and the processing liquid can also be sprayed from the suction surface 321a of the porous plate 321 by utilizing the wafer suction holes 322c.

[0034] As described above, after the suction surface 321a of the chuck table 32 is ground, the wafer 10 is ground as shown in Fig. 6. The suction surface 321a of the chuck table 32 is not ground every time the wafer 10 is ground, but is ground, for example, about once a day. As shown on the left side of the figure, the wafer 10 has a plurality of devices 12 formed on the front surface 10a, which are partitioned by the division lines 14, and a protective tape T is attached to the front surface 10a of the wafer 10 to form an integrated unit. The wafer 10 is inverted and placed on the chuck table 32 that has been moved to the loading / unloading area, with the back surface 10b facing upward and the protective tape T facing downward.

[0035] 4(b), when grinding the back surface 10b of the wafer 10, first, by operating a suction source (not shown), a first suction force (negative pressure) Vm1 is applied to the lower surface 323g of the lower frame 323 of the frame 320, thereby sucking and attracting the frame 320. Furthermore, a second suction force (negative pressure) Vm2 is transmitted to the suction surface 321a of the porous plate 321 via the first communication hole 344 formed in the table base 34 and the wafer suction hole 322c of the upper frame 322, and the wafer 10 is suction-held on the suction surface 321a of the chuck table 32.

[0036] Next, the moving means (not shown) is operated to position the chuck table 32 in the processing area below the grinding means 4, i.e., at a position where the grinding wheel 426 of the grinding means 4 passes through the center of rotation of the chuck table 32 on which the wafer 10 is suction-held. Next, the rotating spindle 422 of the grinding means 4 is rotated in the direction indicated by the arrow R4 at a predetermined rotation speed (e.g., 4000 rpm), and the rotation drive means (not shown) is operated to rotate the chuck table 32 in the direction indicated by the arrow R5 at a predetermined rotation speed (e.g., 300 rpm). At this time, the cooling water supply source is operated to supply cooling water W to the cooling water passage 323b formed inside the frame 320 through the cooling water supply hole 343 of the table base 34. Next, the machining fluid supply means 5 is operated to supply the machining fluid L (grinding water), and the grinding feed means 7 is operated to lower the grinding means 4 in the direction indicated by the arrow R6 at a predetermined lowering speed (for example, 0.1 μm / sec), so that the grinding wheel 426 comes into contact with the back surface 10b of the wafer 10, and the wafer 10 is ground to a desired thickness while the thickness of the wafer 10 is detected by a thickness detection means (not shown). While the grinding is being performed, the operation of the cooling water supply source is continued, and the cooling water W flows through the cooling water passage 323b formed inside the frame 320 and is discharged from the cooling water ejection hole 323d, so that the frame 320 is cooled to a predetermined temperature. Once the grinding is performed, the grinding feed means 7 is stopped to complete the grinding process.

[0037] According to the above-described embodiment, when grinding the suction surface 321a of the porous plate 321 of the chuck table 32 and when grinding the wafer 10, the entire frame 320 of the chuck table 32 is securely fixed onto the table base 34 and maintained at a predetermined temperature by the cooling water W, and grinding is performed by the grinding wheel 425 of the grinding means 4, so that the shape of the holding surface of the chuck table 32 matches the shape of the grinding surface of the wafer 10, thereby suppressing the occurrence of thickness variations in the wafer 10 after grinding.

[0038] In addition, in the above-mentioned embodiment, the wafer suction hole 322c, which transmits suction force to the adsorption surface 321a of the porous plate 321 that constitutes the holding surface of the chuck table 32, and the frame suction hole 342, which attracts the frame body 320 of the chuck table 32 to the mounting surface 341 of the table base 34 by suction, are formed independently. This prevents the machining liquid L mixed with grinding debris sucked from the porous plate 321 of the chuck table 32 from entering between the mounting surface 341 of the table base 34 and the frame body 320, and also suppresses thickness variations in the wafer 10 caused by the grinding debris.

[0039] Furthermore, after grinding the back surface 10b of the wafer 10, the mixed fluid of air and water is supplied to the porous plate 321 using the wafer suction hole 322c to be ejected, and when the wafer 10 is removed from the chuck table 32 and carried out, the machining liquid L mixed with the grinding debris that has entered the wafer suction hole 322c can also be ejected together, but since the wafer suction hole 322c and the frame suction hole 342 are independent, the machining liquid L mixed with the grinding debris is prevented from entering between the mounting surface 341 of the table base 34 and the frame 320, and similarly to the above, the thickness variation of the wafer 10 caused by the grinding debris is also suppressed. Moreover, even if the above processing device is a device that performs polishing processing of the wafer using free abrasive grains, the free abrasive grains are prevented from reaching the mounting surface 341 of the table base 34, and the thickness variation of the wafer caused by the polishing debris is also suppressed. Furthermore, since a cooling water passage 323b is formed inside the frame body 320, the chuck table 32 can be maintained at a predetermined temperature by cooling water W, which suppresses thermal expansion of the frame body 320 and also suppresses thickness variations of the wafer 10.

[0040] The present invention is not limited to the processing apparatus of the first embodiment described above, but may be a second embodiment described below. The second embodiment described below with reference to Figures 7 and 8 differs from the grinding apparatus 1 of the first embodiment described based on Figure 1 only in the configuration of the holding means 3', and therefore the description of the grinding apparatus 1 as a whole will be omitted, and the same components as the holding means 3 described above will be assigned the same numbers, and the description of the same components will be omitted as appropriate.

[0041] As shown in FIG. 7, the holding means 3' includes at least a chuck table 32' and a table base 34' that detachably supports the chuck table 32'. As shown on the right side of the figure, the chuck table 32' includes a porous plate 321 having an adsorption surface 321a that adsorbs the wafer 10, and a frame 320' that surrounds the porous plate 321 except for the adsorption surface 321a, i.e., the side surface 321b and the back surface 321c opposite to the adsorption surface 321a. As shown in the figure, the frame 320' of this embodiment is disassembled into an upper frame 322' and a lower frame 323. The lower frame 323 of this embodiment has the same configuration as the lower frame 323 employed in the above-mentioned embodiment described above. The upper frame 322' includes a sidewall 322h' having a frame upper surface 322a' and constituting a side surface, a plurality of wafer suction holes 322c' formed in the sidewall 322h' for transmitting a suction force (negative pressure) to the suction surface 321a of the porous plate 321, a peripheral step portion 322d' formed along the sidewall 322h', and a plurality of bolt holes 322e' formed in the peripheral step portion 322d' for fixing the frame 320' to the table base 34'.

[0042] In the upper frame 322', two straight grooves 322f' are formed on a plate mounting surface 322b' on which the back surface 321c of the porous plate 321 is mounted, the two straight grooves 322f' connecting and intersecting with each other four wafer suction holes 322c' formed in a side wall 322h' of the upper frame 322'. The lower surface 322g' of the upper frame 322' is a flat surface.

[0043] As shown on the left side of Figure 7, the table base 34' is composed at least of a mounting surface 341' on which the lower surface 323g of the frame body 320' opposite to the plate mounting surface 322b' on which the porous plate 321 of the frame body 320' is mounted, a frame body suction hole 342' that sucks and attracts the lower surface 323g of the lower frame body 323 that constitutes the frame body 320' by operating a suction source not shown, a cooling water supply hole 343' that supplies cooling water to the cooling water supply hole 323c of the lower frame body 323 shown on the right side of the figure, and a second communication hole 344' formed in the side of the table base 34' that is connected to the wafer suction hole 322c' formed in the upper frame body 322' and is connected to a suction source not shown by a path independent of the above-mentioned frame body suction hole 342'. In this embodiment, a mounting surface 341' of a table base 34' is formed with an expanded diameter portion 342a' surrounding the frame suction hole 342' and an annular groove 343a' annularly connecting a plurality of cooling water supply holes 343'.

[0044] In this embodiment, the frame suction hole 342' is formed in the central region of the mounting surface 341' of the table base 34', and the outer circumferential edge of the mounting surface 341' has a bolt fastening hole 345' formed at a position corresponding to the bolt hole 322e' formed in the frame 320' of the chuck table 32'. As can be seen from FIG. 7 and FIG. 8(a), the chuck table 32' and the table base 34' are integrated by inserting the fastening bolt 8 into the bolt fastening hole 345' formed in the mounting surface 341' of the table base 34' through the bolt hole 322e' formed in the frame 322' of the chuck table 32' and fastening them, and the wafer suction hole 322c' and the second communication hole 344' are communicated with each other by a communication passage 346.

[0045] Furthermore, as can be understood by referring to Fig. 8(b) showing a partial schematic cross-sectional view of the holding means 3', the second communication hole 344' is connected to a suction source (not shown) through a path independent of the above-mentioned frame suction hole 342'. Note that the partial schematic cross-sectional view shown in Fig. 8(b) shows a combination of cross sections at different positions from Fig. 4(b) in order to explain the communication configuration of the communication passage 346.

[0046] According to the holding means 3' shown as the second embodiment in Figures 7 and 8, the table base 34' has a frame suction hole 342' formed in a mounting surface 341' on which the lower surface 323g of the frame 320' is mounted, so that the frame 320' can be attracted by suction by operating a suction source (not shown) to apply a first suction force (negative pressure) Vm1 to the lower surface 323g of the frame 320'. When the wafer 10 is mounted on the suction surface 321a of the porous plate 321 and held by suction, the second suction force (negative pressure) Vm2 is transmitted to the suction surface 321a of the porous plate 321 via the second communication hole 344', the communication passage 346, and the wafer suction hole 322c' formed in the table base 34' to hold the wafer 10 by suction. Moreover, by operating a cooling water supply source (not shown), cooling water W can be supplied to the cooling water passage 323b formed inside the frame 320' through a cooling water supply hole 343' of the table base 34'.

[0047] In the second embodiment shown in Figures 7 and 8, the frame suction hole 342' and the second communication hole 344' are connected to the suction source by independent suction paths, and the frame 320' is provided with a cooling water passage 323b inside, so that the same effect as the holding means 3 of the first embodiment described based on Figures 2 to 4 can be achieved. Furthermore, according to this embodiment, the suction force Vm2 transmitted to the adsorption surface 321a of the porous plate 321 held by the frame 322' is supplied by the wafer suction hole 322c' formed in the side wall 322h' of the frame 322', the communication path 346, and the second communication hole 344' without passing through the mounting surface 341' of the table base 34'. This more reliably avoids the problem that the machining liquid L mixed with grinding chips gets into between the mounting surface 341' of the table base 34' and the frame 320', and the thickness variation of the wafer 10 caused by the grinding chips is further suppressed. [Explanation of symbols]

[0048] 1: Grinding equipment (processing equipment) 2: Device housing 21: Main body 22: Upright wall 3: Chuck table mechanism 32: Chuck table 320: Frame 321:Porous plate 321a: Adsorption surface 321b: Side 321c: Back side 322: Upper frame 322a: Top of frame 322b: Plate mounting surface 322c: Wafer suction hole 322d: Outer periphery step 322e: Bolt hole 322f: Annular groove 322g::Bottom side 322h: side wall 323: Lower frame 323a: Surface 323b: Cooling waterway 323c: Cooling water supply hole 323d: Cooling water outlet 323e:Through hole 323f: Bolt hole 323g: bottom surface 34: Table base 341: Placement surface 342:Frame supply hole 343: Cooling water supply hole 344: First communication hole 345: Bolt fastening hole 3': Chuck table mechanism 32': Chuck table 320':Frame 321:Porous plate 321a: Adsorption surface 321b: Side 321c: Back side 322': Upper frame 322a': Top of frame 322b': Plate mounting surface 322c': Wafer suction hole 322d': Outer periphery step 322e': Bolt hole 322f': Annular groove 322g': Bottom surface 322h': Side wall 323: Lower frame 323a: Surface 323b: Cooling waterway 323c: Cooling water supply hole 323d: Cooling water outlet 323e:Through hole 323f: Bolt hole 323g: bottom surface 34': Table base 341': Placement surface 342':Frame supply hole 343': Cooling water supply hole 344': Second connecting hole 345': Bolt fastening hole 4: Grinding method 5: Machining liquid supply means 6a, 6b: bellows means 7: Grinding feed means 8: Bolt 10: Wafer

Claims

1. A processing apparatus comprising at least a holding means for suction-holding a wafer, a processing means having a rotatable grinding wheel for grinding the wafer held by the holding means, and a processing liquid supplying means for supplying a processing liquid to the wafer, the holding means includes a chuck table for holding a wafer, and a table base for detachably supporting the chuck table; the chuck table includes a porous plate having an adsorption surface for adsorbing a wafer, a frame surrounding the porous plate except for the adsorption surface, a cooling water passage formed inside the frame for distributing cooling water, a wafer suction hole formed in the frame for transmitting a suction force to the adsorption surface of the porous plate, and a bolt hole formed in the frame for fixing the chuck table to the table base; the table base includes a support surface on which the lower surface of the frame is placed, a frame suction hole formed in the support surface for attracting the frame by suction, and a cooling water supply hole communicating with the cooling water passage for supplying cooling water to the cooling water passage; The wafer suction hole is formed on the plate mounting surface of the frame on which the porous plate is placed, and a communication hole is formed in the mounting surface of the table base which is connected to the wafer suction hole and transmits suction force independently of the frame suction hole.

2. A processing apparatus comprising at least a holding means for suction-holding a wafer, a processing means having a rotatable grinding wheel for grinding the wafer held by the holding means, and a processing liquid supplying means for supplying a processing liquid to the wafer, the holding means includes a chuck table for holding a wafer, and a table base for detachably supporting the chuck table; the chuck table includes a porous plate having an adsorption surface for adsorbing a wafer, a frame surrounding the porous plate except for the adsorption surface, a cooling water passage formed inside the frame for distributing cooling water, a wafer suction hole formed in the frame for transmitting a suction force to the adsorption surface of the porous plate, and a bolt hole formed in the frame for fixing the chuck table to the table base; the table base includes a support surface on which the lower surface of the frame is placed, a frame suction hole formed in the support surface for attracting the frame by suction, and a cooling water supply hole communicating with the cooling water passage for supplying cooling water to the cooling water passage; The wafer suction hole is formed in a side surface of the frame, and a communication hole for transmitting a suction force independently of the frame suction hole is formed in a side surface of the table base.

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