Processing equipment

Abstract

To provide a processing device capable of solving the problem that a form of a frame body constituting a chuck table is not fixed between a case where grinding is performed on a holding surface of the chuck table and a case where the grinding is performed while adsorbing and holding a wafer on the holding surface of the chuck table.SOLUTION: In a grinding device, holding means 3 for adsorbing and holding a wafer comprises a chuck table 32 which holds the wafer, and a table base 34 which supports the chuck table in a freely removable manner. The chuck table is formed into a frame body 322 enclosing a porous plate 321 including an adsorption face 321a adsorbing the wafer other than the adsorption face and includes a wafer adsorption hole 322c transmitting adsorption power to the adsorption face of the porous pate. The table base includes a frame body suction hole 342 which is formed on a mounting surface and sucks and draws the frame body, on a mounting surface 341 for mounting therein a bottom face 322g at an opposite side of a face 322b on which the porous plate of the frame body is mounted.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 for grinding the wafer held by the holding means, and a processing liquid supplying means for supplying grinding water as a processing liquid to the wafer, and can process the wafer to a desired thickness (see, for example, Patent Document 1).

[0004] The processing device disclosed in Patent Document 1 can supply free abrasive grains as a processing liquid to the back surface of the wafer and can process the back surface of the wafer into 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 chuck table except for 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 reliably sucked and held. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication 2005-153090 Summary of the Invention [Problem to be solved by the invention]

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

[0007] However, even if a wafer is actually ground by the above-mentioned processing method, it has been found that minute thickness variations (for example, about 2 to 3 μm) occur when the wafer thickness after processing is measured. This does not pose a big problem when the target thickness of the wafer is large (thick), but when the target wafer thickness has become extremely thin as in recent years, such minute thickness variations can become a big problem.

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

[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 grinding the holding surface of the chuck table and when a wafer is held by suction to the holding surface of the chuck table and ground. [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 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 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 a wafer, a frame surrounding the porous plate except for the adsorption surface, wafer suction holes formed in the frame for transmitting a suction force to the adsorption surface of the porous plate, and bolt holes formed in the frame for fixing the frame to the table base, the table base including a mounting surface for mounting the surface of the frame opposite to the surface on which the porous plate is mounted, and a bolt hole formed in the mounting surface for attracting the frame by suction. Generate the first attraction A frame suction hole and The wafer suction hole is connected to a suction source via a path independent of a path for generating a first suction force in the frame suction hole, and is capable of generating a second suction force. Even in a state in which the second suction force is not generated in the wafer suction hole, the first suction force is generated in the frame suction hole to suck the frame. A processing apparatus is provided.

[0011] The wafer suction hole is formed so as to open on the surface of the frame opposite to the surface on which the porous plate is placed, and a communication hole that communicates with the wafer suction hole and is independent of the frame suction hole can be formed on the placement surface of the table base. 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 a wafer, a frame surrounding the porous plate except for the adsorption surface, wafer suction holes formed in the frame for transmitting a suction force to the adsorption surface of the porous plate, and bolt holes formed in the frame for fixing the frame to the table base, the table base including at least a mounting surface for mounting the surface of the frame opposite to the surface on which the porous plate is mounted, and a frame suction hole formed in the mounting surface for attracting the frame by suction, The wafer suction hole is formed so as to open on a side surface of the frame, and a communication hole that communicates with the wafer suction hole is formed on a side surface of the table base. A processing apparatus is provided. Effect of the Invention

[0012] 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 a wafer, a frame surrounding the porous plate except for the adsorption surface, wafer suction holes formed in the frame for transmitting a suction force to the adsorption surface of the porous plate, and bolt holes formed in the frame for fixing the frame to the table base, the table base including a mounting surface for mounting the surface of the frame opposite to the surface on which the porous plate is mounted, and a bolt hole formed in the mounting surface for attracting the frame by suction. Generate the first attraction A frame suction hole and The wafer suction hole is connected to a suction source via a path independent of a path for generating a first suction force in the frame suction hole, and is capable of generating a second suction force. Even in a state in which the second suction force is not generated in the wafer suction hole, the first suction force can be generated in the frame suction hole to suck the frame. Therefore, when grinding the adsorption surface of the porous plate of the chuck table or when grinding a wafer, grinding is performed by the grinding wheel of the processing means with the entire frame of the chuck table securely fixed to the table base, 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 porous plate except for the adsorption surface, wafer suction holes formed in the frame for transmitting a suction force to the adsorption surface of the porous plate, and bolt holes formed in the frame for fixing the frame to the table base, the table base ... and a bolt hole formed in the frame for fastening the frame to the table base. The table base is composed of at least a support surface on which the surface opposite to the surface on which the porous plate is placed is placed, and a frame suction hole formed on the support surface which attracts the frame by suction, and the wafer suction hole is formed so as to open to the side of the frame, and a communicating hole which communicates with the wafer suction hole is formed in the side of the table base.Therefore, when grinding the adsorption surface of the porous plate of the chuck table and when grinding a wafer, grinding is performed by a grinding wheel of the processing means with the entire area of ​​the frame of the chuck table securely fixed to the table base, 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 an embodiment of the present invention; [Diagram 2] 2A and 2B are a perspective view and an exploded perspective view of a chuck table mechanism of the grinding apparatus shown in FIG. [Diagram 3] 3 is a schematic cross-sectional view of a portion of the chuck table mechanism shown in FIG. 2. [Figure 4] 2 is a perspective view showing a manner in which a holding surface of a chuck table is ground in the grinding apparatus shown in FIG. 1. [Diagram 5] 2 is a perspective view showing a mode of grinding a wafer in the grinding apparatus shown in FIG. 1. [Figure 6]1A is a perspective view and an exploded perspective view showing another embodiment of a chuck table mechanism, and FIG. 1B is a schematic cross-sectional view of a portion of the chuck table mechanism shown in FIG. 1A. 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 which is a processing apparatus of this embodiment. The grinding apparatus 1 shown in Fig. 1 includes a chuck table mechanism 3 as a holding means 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 wafer 10 held by the chuck table mechanism 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 chuck table mechanism 3 is disposed in the main body 21 and includes bellows means 6a, 6b connected to both sides in the X-axis direction indicated by the arrow X. A moving means (not shown) for moving the chuck table mechanism 3 in the direction indicated by the arrow X in the figure is housed inside the main body 21. By operating the moving means, the bellows means 6a, 6b can be contracted and extended, and the chuck table mechanism 3 can be moved between a loading / unloading 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 chuck table mechanism 3 of this embodiment will be described in more detail with reference to Fig. 2. The chuck table mechanism 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 in the figure, the chuck table 32 includes a porous plate 321 having an adsorption surface 321a that adsorbs the wafer 10, and a frame 322 that surrounds the porous plate 321 except for the adsorption surface 321a, i.e., a side surface 321b and a back surface 321c opposite to the adsorption surface 321a. The frame 322 includes a side wall 322h having a frame upper surface 322a and constituting a side surface, a plate mounting surface 322b on which the back surface 321c of the porous plate 321 is mounted, a plurality of wafer suction holes 322c formed to open on a bottom surface 322g opposite to the plate mounting surface 322b and transmitting 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 322 to the table base 34. The plurality of wafer suction holes 322c opening on 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 porous plate 321 in this embodiment is formed, for example, from 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.

[0019] As shown on the left side of Fig. 2, the table base 34 is composed of at least a mounting surface 341 on which a bottom surface 322g of the frame body 322 opposite to the surface on which the porous plate 321 of the frame body 322 is mounted is mounted, and a frame body suction hole 342 formed in the mounting surface 341 and attracting the bottom surface 322g of the frame body 322 by suction by operating a suction source (not shown). The frame body suction hole 342 of this embodiment is formed in the central region of the mounting surface 341 of the table base 34, and a bolt fastening hole 343 with a female thread is formed at a position corresponding to the bolt hole 322e formed in the frame body 322 of the chuck table 32 described above on the outer periphery of the mounting surface 341 of the table base 34. An enlarged diameter portion 342a having a diameter larger than that of the frame body suction hole 342 is formed on the mounting surface 341 side of the frame body suction hole 342.

[0020] Furthermore, the mounting surface 341 of the table base 34 is formed with a plurality of first communication holes 344 which communicate with the wafer suction holes 322c formed in the frame 322 of the chuck table 32 and are connected to a suction source (not shown) through a path independent of the frame suction holes 342. Further, the mounting surface 341 of the table base 34 in this embodiment is formed with an annular groove 344a which communicates with the plurality of first communication holes 344.

[0021] The chuck table 32 and the table base are integrated by inserting a fastening bolt 8 through a bolt hole 322e formed in the frame 322 of the chuck table 32 and fastening it to a bolt fastening hole 343 of the table base .

[0022] 3 shows a schematic cross-sectional view of a part of the chuck table mechanism 3 in which the chuck table 32 and the table base 34 are integrated. As shown in the figure, the table base 34 has frame suction holes 342 formed in a mounting surface 341 on which the frame 322 is mounted, and by operating a suction source (not shown), a first suction force (negative pressure) Vm1 is applied to the bottom surface 322g of the frame 322 of the chuck table mechanism 3, so that the frame 322 can be attracted by suction. In addition, if 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 first communication hole 344 formed in the table base 34 and the wafer suction hole 322c of the frame 322, so that the wafer 10 can be held by suction. And. 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 322 can be attracted to the table base 34 and held by suction.

[0023] 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.

[0024] 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.

[0025] 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. The grinding feed means 7 consisting of such a screw mechanism can rotate the pulse motor 72 in the forward direction to lower the grinding means 4 together with the movable base 41, and can raise the grinding means 4 together with the movable base 41 by rotating the pulse motor 74 in the reverse direction.

[0026] The grinding device 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 chuck table mechanism 3. The machining fluid supply means 5 includes 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.

[0027] The grinding device 1 of this embodiment has a configuration generally as described above, and its functions and actions will be described below.

[0028] As described above, when the wafer 10 is ground 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 as shown in Fig. 4. When performing the grinding, first, as described based on Fig. 3, a suction source (not shown) is operated to apply a first suction force (negative pressure) Vm1 to the bottom surface 322g of the frame body 322 constituting the chuck table mechanism 3, thereby sucking and attracting the frame body 322. At this time, since the wafer 10 is not placed on the holding surface 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 of the frame body 322.

[0029] 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 center of rotation of the chuck table 32 passes through the grinding wheel 426 of the grinding means 4. Next, the rotating spindle 422 of the grinding means 4 is rotated in the direction indicated by the arrow R1 at a predetermined rotational 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 R2 at a predetermined rotational speed (e.g., 300 rpm). Next, the grinding means 4 is lowered in the direction indicated by the arrow R3 by operating the grinding feed means 7, and while supplying the processing liquid L (grinding water) to the holding surface 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) for a certain period of time, the grinding feed means 7 is stopped, and then an idle operation is performed for a predetermined period of time to make the holding surface of the chuck table 32 flat, completing the grinding process. The supply of the processing liquid L to the holding surface of the chuck table 32 is preferably performed using the processing liquid supply means 5 described above, and the processing liquid L is also preferably sprayed from the suction surface 321a of the porous plate 321 by utilizing the wafer suction holes 322c.

[0030] As described above, the frame body 322 of the chuck table 32 is fixed by a plurality of bolts 8, and is also attracted by the frame body suction holes 342, so that the entire area of ​​the frame body 322 is securely fixed on the mounting surface 341 of the table base 34. In this state, the adsorption surface 321a of the porous plate 321 that constitutes the holding surface of the chuck table 32 is ground.

[0031] As described above, after the holding surface of the chuck table 32 is ground, grinding is performed on the wafer 10, which is the workpiece of this embodiment, as shown in Fig. 5. The wafer 10 has a plurality of devices 12 formed on its front surface 10a, which is partitioned by 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 turned over and placed on the holding surface of the chuck table 32, which has been moved to the loading / unloading area, with the back surface 10b facing upward and the protective tape T facing downward.

[0032] 3, when grinding the back surface 10b of the wafer 10, a suction source (not shown) is first operated to apply a first suction force (negative pressure) Vm1 to the bottom surface 322g of the frame 322 constituting the chuck table mechanism 3, thereby sucking and attracting the frame 322. Furthermore, a second suction force (negative pressure) Vm2 is transmitted to the adsorption 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 frame 322, and the wafer 10 is sucked and held on the holding surface of the chuck table 32.

[0033] Next, a 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 center of rotation of the chuck table 32 passes through the grinding wheel 426 of the grinding means 4. Next, a rotation drive means (not shown) is operated to rotate the chuck table 32 in the direction indicated by the arrow R4 at a predetermined rotation speed (e.g., 300 rpm), and rotate the rotating spindle 422 of the grinding means 4 in the direction indicated by the arrow R5 at a predetermined rotation speed (e.g., 4000 rpm). Next, the machining fluid supply means 5 is operated to supply machining fluid L (grinding water), and the grinding feed means 7 described above is operated to lower the grinding means 4 in the direction indicated by the arrow R6 at a predetermined lowering speed (e.g., 0.1 μm / sec) to bring the grinding wheel 426 into contact with the back surface 10b of the wafer 10. Once the wafer 10 has been ground to the desired thickness while the thickness of the wafer 10 is detected by a thickness detection means not shown, the grinding feed means 7 is stopped, and then, as in the case of grinding the holding surface of the chuck table 32, an idle operation is performed for a predetermined period of time to flatten the back surface 10b of the wafer 10 and complete the grinding process.

[0034] 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, grinding is performed by the grinding wheel 425 of the grinding means 4 with the entire frame 322 of the chuck table 32 securely fixed to the table base 34, so that the shape of the holding surface of the chuck table 32, i.e., the suction surface 321a of the porous plate 321, matches the shape of the grinding surface of the wafer 10, thereby suppressing the occurrence of thickness variations in the wafer 10 after grinding.

[0035] In addition, in the above-mentioned embodiment, the wafer suction hole 322c, which transmits a suction force to the adsorption surface 321 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 322 of the chuck table 32 to the mounting surface 341 of the table base 34 by suction, are independent of each other. This prevents the machining fluid 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 322, and also suppresses thickness variations in the wafer 10 caused by the grinding debris.

[0036] Furthermore, after grinding the back surface 10b of the wafer 10, a mixed fluid of air and water is supplied to the porous plate 321 using the wafer suction hole 322c and sprayed out, and when the wafer 10 is moved away from the chuck table 32 and removed, the machining liquid L mixed with the grinding debris that has entered the wafer suction hole 322c is also sprayed out. However, 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 322, and similarly to the above, the thickness variation of the wafer 10 caused by the grinding debris is also suppressed.

[0037] It should be noted that the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the chuck table mechanism 3 exemplified as the holding means of the present invention may be in another embodiment as described below.

[0038] Another chuck table mechanism 3' configured according to the present invention will be described with reference to Fig. 6. Note that the same components as those in the chuck table mechanism 3 described above are given the same numbers, and descriptions of the same components will be omitted as appropriate.

[0039] The chuck table mechanism 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 in the figure, the chuck table 32' includes a porous plate 321 having an adsorption surface 321a that adsorbs the wafer 10, and a frame 322' that surrounds the porous plate 321 except for the adsorption surface 321a, i.e., a side surface 321b and a back surface 321c opposite to the adsorption surface 321a. The 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 to open in the sidewall 322h' and 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 322' to the table base 34'. In the frame 322', two straight grooves 322f' are formed in a plate mounting surface 322b' on which the back surface 321c of the porous plate 321 is mounted, the two straight grooves 322f' connecting the four suction holes 322c' formed in the sidewall 322h' of the frame 322' and intersecting at right angles.

[0040] As shown on the left side of FIG. 6, the table base 34' is composed of at least a mounting surface 341' on which a bottom surface 322g' of the frame body 322' opposite to the plate mounting surface 322b' on which the porous plate 321 of the frame body 322' is mounted, and a frame body suction hole 342' formed in the mounting surface 341' and attracting the bottom surface 322g' of the frame body 322' by suction by operating a suction source not shown. The frame body suction hole 342' in this embodiment is formed in the central region of the mounting surface 341' of the table base 34', and a bolt fastening hole 343' is formed in the outer peripheral edge part of the mounting surface 341' at a position corresponding to the bolt hole 322d' formed in the frame body 322' of the chuck table 32' described above. An expanded diameter portion 342a' having a diameter larger than that of the frame body suction hole 342' is formed on the mounting surface 341' side of the frame body suction hole 342'.

[0041] Furthermore, as can be understood by also referring to the partial schematic cross-sectional view of the chuck table mechanism 3' shown in Figure 6(b), a second communication hole 344' is formed on the side 345 of the table base 34'. The second communication hole 344' is connected to the wafer suction hole 322c' formed in the frame 322' of the chuck table 32' described above, and is connected to a suction source (not shown) via a path independent of the frame suction hole 342' described above.

[0042] The chuck table 32' and the table base 34' are integrated by inserting fastening bolts 8 through bolt holes 322e' formed in the frame 322' of the chuck table 32' and fastening them to bolt fastening holes 343' of the table base 34', and further, the wafer suction hole 322c' and the second communication hole 344' are connected by a communication passage 346.

[0043] According to the chuck table mechanism 3' shown in Fig. 6, the table base 34' has a frame suction hole 342' formed to open to a mounting surface 341' on which a bottom surface 322g' of the frame 322' is mounted, and by operating a suction source (not shown), a first suction force (negative pressure) Vm1 is applied to the bottom surface 322g' of the frame 322' to suck and attract the frame 322'. 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.

[0044] In the embodiment shown in Fig. 6, the frame suction hole 342' and the second communication hole 344' are connected to the suction source by independent suction paths, and the same effect as the previous embodiment described based on Fig. 2 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 further prevents the problem that the machining liquid L mixed with grinding debris gets into between the mounting surface 341' of the table base 34' and the frame 322', and further suppresses the thickness variation of the wafer 10 caused by the grinding debris. [Explanation of symbols]

[0045] 1: Grinding device 2: Device housing 21: Main body 22: Upright wall 221: Guide rail 3, 3': Chuck table mechanism 31, 31': Table cover 32, 32': Chuck table 321:Porous plate 321a: Adsorption surface 321b: Side 321c: Back side 322, 322': Frame 322a, 322a': Frame top surface 322b, 322b': plate mounting surface 322c, 322c': Wafer suction hole 322d, 322d': outer periphery step 322e, 322e': Bolt holes 322g, 322g': Bottom 322h, 322h': Side wall 34, 34': Table base 341, 341': placement surface 342, 342': Frame suction hole 343, 343': Bolt fastening holes 344: First communication hole 344': Second connecting hole 345: Side 346: Communication path 4: Grinding method 41: Mobile base 42: Spindle unit 421: Spindle housing 422: Rotating spindle 423: Servo motor 424: Mounter 425: Grinding wheel 426: Grinding wheel 5: Machining liquid supply means 51: Machining fluid tank 52: Machining fluid supply path 53: Opening and closing valve 6a, 6b: bellows means 7: Grinding feed means 71: Rod 72: Pulse motor 8: Bolt 10: Wafer Vm1: First attraction Vm2: Second suction power

Claims

1. a holding means for holding a wafer by suction, 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; A processing apparatus comprising at least 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, wafer suction holes formed in the frame for transmitting a suction force to the adsorption surface of the porous plate, and bolt holes formed in the frame for fixing the frame to the table base; The table base is at least composed of a mounting surface for mounting a surface of the frame opposite to the surface on which the porous plate is mounted, and a frame suction hole formed on the mounting surface for generating a first suction force that attracts the frame by suction; The wafer suction hole is connected to a suction source via a path independent of the path for generating a first suction force at the frame suction hole, thereby generating a second suction force, and the processing apparatus is configured so that even when the second suction force is not generated at the wafer suction hole, the first suction force can be generated at the frame suction hole to suck in the frame.

2. The processing apparatus described in claim 1, wherein the wafer suction hole is formed so as to open to the surface of the frame opposite the surface on which the porous plate is placed, and a communication hole is formed in the placement surface of the table base that communicates with the wafer suction hole and is independent of the frame suction hole.

3. A wafer processing apparatus comprising: a holding means for holding a wafer by suction; 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. A processing apparatus comprising at least 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, wafer suction holes formed in the frame for transmitting a suction force to the adsorption surface of the porous plate, and bolt holes formed in the frame for fixing the frame to the table base; The table base is at least composed of a mounting surface for mounting a surface of the frame opposite to the surface on which the porous plate is mounted, and a frame suction hole formed on the mounting surface for attracting the frame by suction, The wafer suction hole is formed so as to open on a side surface of the frame, and a communication hole communicating with the wafer suction hole is formed on a side surface of the table base.

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