Chuck table and machining device

Abstract

The present application provides a chuck table and a processing device, which miniaturize the chuck table. The chuck table (2) has a holding surface (210) that holds a workpiece (14), and a measurement surface (230) that is formed on a first measurement track (241) of an upper surface height measurer (6) that relatively moves with respect to the chuck table by rotating the chuck table using a table rotating unit (25) in a state where the upper surface height measurer (6) is positioned above the holding surface, and is formed at a position other than the holding surface (210). When measuring the thickness of the workpiece (14), the chuck table is rotated in a state where the upper surface height measurer (6) is positioned on the first measurement track (241). Since the chuck table does not need to have a ring-shaped measurement surface, miniaturization can be achieved compared to a conventional chuck table having a ring-shaped measurement surface.

Description

TECHNICAL FIELD

[0001] The present application relates to a chuck table and a processing device. BACKGROUND

[0002] In a processing device including a grinding device that grinds a workpiece held by a holding surface of a chuck table using a grinding tool, the chuck table is rotated about the center of the chuck table, and a processing tool such as a grinding tool or a polishing pad is brought into contact, and processing is performed. The thickness of the workpiece is measured in the processing of the workpiece.

[0003] The thickness of the workpiece is calculated by calculating the difference between the height of the holding surface and the height of the upper surface of the workpiece held by the holding surface. Therefore, in the thickness measurement of the workpiece, the measurement of the height of the holding surface and the measurement of the height of the upper surface of the workpiece are required, and as disclosed in Patent Literature 1, a thickness measurement unit having both a holding surface height gauge and an upper surface height gauge is used.

[0004] As an example of a conventional chuck table Figure 14 The chuck table 9 illustrated in FIG. 1 has a holding surface 90 that holds a workpiece 14, and a ring-shaped measurement surface 91 that positions a not-illustrated holding surface height gauge to measure the height of the holding surface 90, and thereby measures the height. In the thickness measurement of the workpiece 14, in a state where the workpiece 14 is held on the holding surface 90, a not-illustrated upper surface height gauge is positioned on the upper surface 140 of the workpiece 14, and the not-illustrated holding surface height gauge is positioned on the measurement surface 91.

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2020-049557

[0006] The chuck table having the ring-shaped measurement surface outside the holding surface that holds the workpiece as described above is large and heavy, and this becomes a work burden when the chuck table is installed on the processing device or when the chuck table is replaced. SUMMARY

[0007] Therefore, in the chuck table provided to the processing device, there is a problem that it is desired to make the work of installing, replacing, or the like of the chuck table easier.

[0008] The present application is a chuck table used in a processing device, the processing device having at least: the chuck table having a holding surface that holds a workpiece; a table rotating section that rotates the chuck table about the center of the chuck table; a processing unit that processes the workpiece held on the holding surface; an upper surface height measurer that measures the height of the upper surface of the workpiece rotated by the table rotating section in a non-contact manner; and a thickness calculating section that calculates the thickness of the workpiece using the value measured by the upper surface height measurer, wherein the chuck table has a measurement surface that is formed on the measurement track of the upper surface height measurer that relatively moves with respect to the chuck table by rotating the chuck table using the table rotating section in a state where the upper surface height measurer is positioned above the holding surface, and is formed at a position other than the holding surface.

[0009] It is preferable that the above-described chuck table be provided with a plurality of the holding surfaces at positions where the upper surface height measurer can measure.

[0010] It is preferable that the above-described chuck table have: a sub-chuck table having the measurement surface and the holding surface; a base having a connection surface that connects the sub-chuck table; an opening formed in the connection surface of the base; and a communication path formed in the connected surface of the sub-chuck table that communicates the opening and the holding surface.

[0011] The present application is a processing device having: a holding unit that holds a workpiece on a holding surface of a chuck table; a thickness measuring unit that measures the thickness of the workpiece; and a processing unit that processes the workpiece to a predetermined specified thickness, wherein the thickness measuring unit has: an upper surface height measurer that measures the height of the upper surface of the workpiece held on the holding surface and the height of the measurement surface in a non-contact manner; and a thickness calculating section that calculates the difference between the height of the upper surface of the workpiece measured by the upper surface height measurer and the height of the measurement surface, thereby calculating the thickness of the workpiece.

[0012] Since the chuck table of the present application does not require a measurement surface in a ring shape, the chuck table can be made small in size and light in weight.

[0013] In addition, in a structure in which the sub-chuck table is detachably arranged on the base, the sub-chuck table can be replaced on the base, and lightening can be achieved. Also, since the sub-chuck table can be replaced, size changes can be easily performed, and the number of workpieces held can be changed. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1is a perspective view showing the entire machining device.

[0015] Figure 2 is a perspective view of the chuck table.

[0016] Figure 3 is a plan view of the chuck table.

[0017] Figure 4 is a plan view showing the rotation locus of the holding member when the chuck table is rotated.

[0018] Figure 5 is a perspective view of the chuck table.

[0019] Figure 6 is a plan view of the chuck table.

[0020] Figure 7 is a plan view showing the rotation locus of the holding member when the chuck table is rotated.

[0021] Figure 8 is a perspective view of the chuck table.

[0022] Figure 9 is a plan view of the chuck table.

[0023] Figure 10 is a plan view showing the rotation locus of the holding member when the chuck table is rotated.

[0024] Figure 11 is a perspective view of the 2nd chuck table.

[0025] Figure 12 is a perspective view of the 2nd base.

[0026] Figure 13 (a) of FIG. 8 is a perspective view of a base plate showing a state in which a front surface faces upward, Figure 13 (b) of FIG. 8 is a perspective view of a base plate showing a state in which a joining surface faces upward.

[0027] Figure 14 is a perspective view showing a chuck table having a ring-shaped measurement surface.

[0028] Explanation of Reference Numerals

[0029] 1: Machining device; 10: Base; 100: Internal base; 2: Chuck table; 20: Base; 200: Upper surface of base; 21: Holding component; 210: Holding surface; 22: Recess; 223: Threaded hole; 23: Protrusion; 230: Measuring surface; 25: Table rotation part; 250: Rotating component; 251: Annular component; 256: Through hole; 257: Support column; 3: Machining unit; 30: Spindle; 31 31: Spindle housing; 32: Spindle motor; 33: Mounting base; 34: Grinding wheel; 340: Grinding tool; 341: Grinding wheel base; 342: Grinding surface; 35: Rotation axis; 4: Machining feed unit; 40: Ball screw; 41: Guide rail; 42: Z-axis motor; 43: Lifting plate; 44: Cage; 45: Rotation axis; 5: Horizontal movement unit; 50: Ball screw; 51: Guide rail; 52: Y-axis motor; 5 3: Movable plate; 55: Rotation axis; 6: Upper surface height measuring device; 7: Thickness calculation unit; 8: Second chuck worktable; 80: Sub-chuck worktable; 81: Second holding component; 810: Holding surface; 82: Base plate; 820: Front side of base plate; 821: Connected surface; 822: Connecting path; 83: Protrusion; 830: Measuring surface; 84: Second base; 840: Connecting surface; 841: Opening; 842: Recess; 843: Threaded hole; 241: First measuring track; 242: Second measuring track; 243: Third measuring track; 244: Fourth measuring track; 245: Fifth measuring track; 281: First minimum trajectory; 282: Second minimum trajectory; 284: Fourth minimum trajectory; 291: First maximum trajectory; 292: Second maximum trajectory; 294: Fourth maximum trajectory; 9: Chuck table; 90: Holding surface; 91: Measuring surface. Detailed Implementation

[0030] Figure 1 The machining apparatus 1 shown is a machining apparatus that uses machining unit 3 to perform grinding machining on the workpiece 14 held by chuck table 2. The structure of machining apparatus 1 will be described below.

[0031] like Figure 1 As shown, the processing device 1 has a base 10 extending along the Y-axis and a column 11 erected on the +Y direction side of the base 10.

[0032] A machining feed unit 4, which supports the machining unit 3 and allows it to be raised and lowered, is provided on the side of the column 11 in the -Y direction. The machining unit 3 is, for example, a grinding unit, which has: a spindle 30 having a rotation axis 35 in the Z-axis direction; a housing 31 that supports the spindle 30 and allows it to rotate; a spindle motor 32 that drives the spindle 30 to rotate about the rotation axis 35; a mounting base 33 that is connected to the lower end of the spindle 30; and a grinding wheel 34 that is detachably mounted on the lower surface of the mounting base 33.

[0033] The grinding wheel 34 has a grinding wheel base 341 and a plurality of generally cuboid grinding tools 340 arranged in a ring on the lower surface of the grinding wheel base 341. The lower surface of the grinding tools 340 becomes the grinding surface 342 that contacts the workpiece 14.

[0034] The spindle 30 is rotated by using the spindle motor 32, and the mounting base 33 connected to the spindle 30 and the grinding wheel 34 mounted on the lower surface of the mounting base 33 rotate together.

[0035] The machining feed unit 4 includes: a ball screw 40 having a rotation axis 45 in the Z-axis direction; a pair of guide rails 41 arranged parallel to the ball screw 40; a Z-axis motor 42 that causes the ball screw 40 to rotate about the rotation axis 45; a lifting plate 43 with a nut inside that is screwed into the ball screw 40 and its side slidingly contacting the guide rails 41; and a cage 44 connected to the lifting plate 43 to support the machining unit 3.

[0036] When the ball screw 40 is driven by the Z-axis motor 42 and rotates about the rotation axis 45, the lifting plate 43 is guided by the guide rail 41 to move up and down in the Z-axis direction, and the grinding wheel 34 of the processing unit 3 held by the cage 44 moves in the Z-axis direction.

[0037] A chuck worktable 2 is mounted on the base 10. An inner base 100 is mounted inside the base 10, and a horizontal moving unit 5 is mounted on the inner base 100 to move the chuck worktable 2 in the horizontal direction (Y-axis direction).

[0038] The horizontal moving unit 5 includes: a ball screw 50 having a rotation axis 55 in the Y-axis direction; a pair of guide rails 51 arranged parallel to the ball screw 50; a Y-axis motor 52 connected to the ball screw 50 to rotate the ball screw 50 about the rotation axis 55; and a movable plate 53 with a nut at its bottom engaged with the ball screw 50 and moving along the guide rails 51 in the Y-axis direction.

[0039] When the ball screw 50 is driven by the Y-axis motor 52 and rotates around the rotation axis 55, the movable plate 53 is guided by the guide rail 51 and moves along the Y-axis.

[0040] A worktable rotation section 25 is provided on the movable plate 53. The worktable rotation section 25 has a rotating component 250 that supports the chuck worktable 2 so that it can rotate, and an annular component 251 disposed around the rotating component 250. The annular component 251 supports the rotating component 250 in a rotatable state.

[0041] For example, three are formed at equal intervals on the same circumference of the annular component 251. Figure 1 Two through holes 256 are shown in the figure. Three supports for the annular component 251 are erected on the movable plate 53. Figure 1 Two support columns 257 are shown. Each through hole 256 is pierced by a support column 257, which is fixed to the movable plate 53. In addition, each support column 257 has, for example, a telescopic mechanism (not shown), which adjusts the tilt of the chuck table 2 by appropriately telescopically extending or retracting the support column 257 along the Z-axis.

[0042] The rotating component 250 is connected, for example, to a motor (not shown). By actuating the motor, the rotating component 250 is rotated, enabling the chuck table 2 to rotate about the center 2000.

[0043] Furthermore, by using the horizontal moving unit 5 to move the movable plate 53 along the Y-axis direction, the worktable rotating part 25 and the chuck worktable 2 become a structure that moves along the Y-axis direction integrally with the movable plate 53.

[0044] A cover 27 and pleats 28 that are telescopically connected to the cover 27 are provided around the chuck table 2. For example, when the chuck table 2 moves along the Y-axis, the cover 27 moves together with the chuck table 2 along the Y-axis and the pleats 28 extend and retract.

[0045] An upper surface height measuring device 6 is provided on the -X direction side of the base 10. The upper surface height measuring device 6 measures the height of the upper surface 140 of the workpiece 14 that is rotated by the worktable rotation part 25 in a non-contact manner.

[0046] The upper surface height measuring device 6 is, for example, a laser-type height measuring device, which measures the height of the portion into which the laser beam is projected by measuring the reflected light that is reflected from the projected laser beam.

[0047] like Figure 2 As shown, the chuck worktable 2 has a generally circular plate-shaped base 20 and three generally rectangular cuboid-shaped sheet holding members 21 disposed on the upper surface 200 of the base 20.Figure 3 A plan view of the chuck table 2 is shown. Three holding members 21 are arranged, for example, all in parallel with the Y-axis direction, and the one in the middle of the three is slightly offset to the radially inner side (+Y direction side) of the base 20.

[0048] The upper surface of the holding member 21 is a holding surface 210 that holds the plate-shaped workpiece 14. The workpiece 14 can be held on each of the three holding surfaces 210.

[0049] A convex portion 23 is formed on the base 20 of the chuck table 2 at a position other than the holding surface 210. The convex portion 23 is provided, for example, on the radially front side (-Y direction side) of the upper surface 200 of the base 20.

[0050] Figure 4 A view showing the position of the workpiece 14 when the chuck table 2 is rotated with the center 2000 of the chuck table 2 as an axis in a state where the workpiece 14 is held on the holding surface 210 of the holding member 21 is shown. The convex portion 23 is provided at a position inside a first maximum locus 291 obtained by circularly joining the outermost portion of the locus of the workpiece 14 and outside a first minimum locus 281 obtained by circularly joining the innermost portion of the locus of the workpiece 14, the locus of the workpiece 14 being traced by rotating the chuck table 2 with the center 2000 as an axis using the table rotating portion 25 in a state where the workpiece 14 is held on the holding surface 210.

[0051] The upper surface of the convex portion 23 is a measurement surface 230 on which the height is measured by the upper surface height measurer 6. The height of the measurement surface 230 is the same as the height of the holding surface 210, for example, and by measuring the height of the measurement surface 230, the height of the holding surface 210 can be identified.

[0052] Alternatively, the holding surface 210 and the measurement surface 230 can not be formed on the same plane, and a prescribed difference can be provided between the height of the measurement surface 230 and the height of the holding surface 210. In this structure, the measurement surface 230 is formed lower than the upper surface of the machined workpiece 14 held by the holding surface 210. In this structure, by measuring the height of the measurement surface 230 and adding a prescribed difference to the measured height of the measurement surface 230 as appropriate, the height of the holding surface 210 can be identified.

[0053] Further, Figure 4The first measurement track 241 is a movement path of the upper surface height gauge 6 that relatively moves with respect to the chuck table 2 at the time of measurement of the thickness of the workpiece 14. In a state where the upper surface height gauge 6 is positioned above one point on the first measurement track 241, the chuck table 2 is caused to rotate using the table rotation section 25, whereby the upper surface height gauge 6 passes over the first measurement track 241.

[0054] Returning to Figure 2 The base 20 is described. The recess 22 that is recessed toward the -Z direction side is formed on the radially outermost circumferential side of the base 20. A plurality of threaded holes 223 are formed on the upper surface of the recess 22.

[0055] The base 20 is threadedly fixed and installed to the chuck base that is not shown on the upper end of the rotation section 250 by a screw that is not shown corresponding to the threaded holes 223. Figure 1 In the processing device 1, by installing the base 20 of the chuck table 2 to this chuck base, the table rotation section 25 is integrated with the chuck table 2 to constitute a holding unit. By detaching this screw, the base 20 can be attached and detached with respect to this chuck base.

[0056] The holding surface 210 of each holding section 21 is connected to a suction source that is not shown. In a state where the workpiece 14 is placed on the holding surface 210, the suction source is caused to operate, and the generated suction force is transmitted to the holding surface 210, whereby the workpiece 14 can be suction-held to the holding surface 210.

[0057] As shown in Figure 1 The upper surface height gauge 6 is connected to the thickness calculation section 7. The thickness calculation section 7 has a computer including a CPU and a memory, and by calculating the difference between the height of the upper surface 140 of the workpiece 14 measured by the upper surface height gauge 6 and the height of the measurement surface 230 in the thickness calculation section 7, the thickness of the workpiece 14 can be calculated.

[0058] The thickness measurement unit that measures the thickness of the workpiece 14 is constituted by the upper surface height gauge 6 and the thickness calculation section 7.

[0059] The operation of the processing device 1 at the time of grinding processing of the workpiece 14 while calculating the thickness of the workpiece 14 using the processing device 1 is described.

[0060] When the workpieces 14 are ground by using the processing device 1, first, three workpieces 14 are placed on the holding surface 210 of the chuck table 2. Then, an unillustrated suction source connected to the chuck table 2 is operated, and the generated suction force is transmitted to the holding surface 210. Thus, the three workpieces 14 are suction-held to the holding surface 210.

[0061] While the workpieces 14 are suction-held to the holding surface 210, the chuck table 2 is moved by the horizontal moving unit 5 in the +Y direction by a proper distance. Thus, the chuck table 2 is positioned below the processing unit 3, and the upper surface height measurer 6 is positioned above the first measurement track 241 as shown. Figure 2

[0062] Next, the chuck table 2 is rotated by using the table rotating section 25 so that the workpieces 14 held by the holding surface 210 are rotated, and the grinding tool 340 is rotated about the rotation axis 35 by using the spindle motor 32.

[0063] While the chuck table 2 is rotated in the state where the upper surface height measurer 6 is positioned on the first measurement track 241, the upper surface height measurer 6 is repeatedly positioned on the upper surface 140 of the workpiece 14, on the upper surface 200 of the base 20, and on the measurement surface 230 on the first measurement track 241. When the upper surface height measurer 6 is positioned on the upper surface 140 of the workpiece 14, the height of the upper surface 140 of the workpiece 14 is measured. In addition, when the upper surface height measurer 6 is positioned on the measurement surface 230, the height of the measurement surface 230 is measured, and the height of the holding surface 210 is identified. Then, the measured height information of the upper surface 140 of the workpiece 14 and the height information of the measurement surface 230 are transmitted to the thickness calculating section 7, respectively, and the difference between them is calculated in the thickness calculating section 7. Thus, the thickness of the workpiece 14 is calculated.

[0064] While the workpieces 14 are rotated and the grinding tool 340 is rotated about the rotation axis 35, the processing unit 3 is lowered in the -Z direction by using the processing feed unit 4. By lowering the grinding tool 340 in the -Z direction, the grinding surface 342 of the grinding tool 340 comes into contact with the upper surface 140 of the workpiece 14.

[0065] While the grinding surface 342 is in contact with the upper surface 140 of the workpiece 14, the grinding tool 340 is further lowered in the -Z direction, and thus the workpiece 14 is ground.

[0066] While the workpiece 14 is ground, the thickness of the workpiece 14 calculated in the thickness calculating section 7 is reduced.

[0067] ​After the workpiece 14 is ground to a prescribed thickness, the grinding of the workpiece 14 is completed, and after the machining unit 3 is moved in the +Z direction by the machining feed unit 4 to separate the grinding tool 340 from the upper surface 140 of the workpiece 14, the workpiece 14 is carried out from the holding surface 210 of the chuck table 2.

[0068] Figure 14 The conventional chuck table 9 shown has a ring-shaped measurement surface 91 for positioning a measurement device at the time of thickness measurement, and in contrast to this, Figure 2 The chuck table 2 shown does not have such a ring-shaped measurement surface. Therefore, the chuck table 2 can be made small, and weight reduction can be achieved.

[0069] The positions, number, etc. of the holding members 21 provided on the base 20 of the chuck table 2 are not limited to the above.

[0070] For example, as shown in Figure 5 The three holding members 21 can also be arranged in parallel with the X axis direction in a state in which the positions in the Y axis direction of the respective short sides are identical on the upper surface 200 of the base 20. Figure 6 A plan view of the chuck table 2 at this time is shown. In addition, Figure 7 A view in which the positions of the workpiece 14 when the chuck table 2 has been rotated with the center 2000 of the base 20 of the chuck table 2 as an axis in a state in which the workpiece 14 is held by the chuck table 2 are depicted and superimposed every time the chuck table 2 is rotated by 45 degrees is shown.

[0071] In this structure, the convex portion 23 is provided at a position inside a second largest track 292 that is obtained by circularly joining the outermost portions in the rotational track of the workpiece 14 and outside a second smallest track 282 that is obtained by circularly joining the innermost portions.

[0072] Furthermore, as one of the tracks of the upper surface 200 of the base 20 and the respective holding surfaces 210 of the three holding members 21, a second measurement track 242 is provided, and the upper surface height gauge 6 is positioned on the second measurement track 242 at the time of measuring the thickness of the workpiece 14.

[0073] In addition, as Figure 8As shown, the chuck table 2 can also have a structure in which four holding members 21 are mounted on the base 20. In this case, with the workpiece 14 held on the holding surfaces 210 of each holding member 21, a measuring surface 230 is provided inside the maximum trajectory and outside the minimum trajectory of the workpiece 14 as it rotates around the center 2000. Furthermore, a third measuring track 243 is provided as one of the tracks connecting the holding surfaces 210 and measuring surfaces 230 of the four holding members 21, and the upper surface height measuring device 6 is positioned on the third measuring track 243 when measuring the thickness of the workpiece 14. In this structure, by holding the workpiece 14 on the holding surfaces 210 of the four holding members 21 respectively, grinding can be performed on up to four workpieces 14 simultaneously.

[0074] In addition, such as Figure 9 As shown, it can also be a structure in which a sheet holding component 21 is provided on the base 20 of the chuck worktable 2. Figure 10 The diagram shows the position of the workpiece 14 when the chuck table 2 rotates about the center 2000 of the base 20 of the chuck table 2 while the workpiece 14 is held on the holding member 21. The position of the workpiece 14 is depicted and superimposed with each rotation of the chuck table 2 by 45 degrees. In this structure, the protrusion 23 is located inside the fourth maximum trajectory 294, which is formed by the outermost part of the rotation trajectory of the workpiece 14 in a circular engagement, and outside the fourth minimum trajectory 284, which is formed by the innermost part in a circular engagement. Furthermore, a fourth measuring track 244 is provided as one of the tracks between the holding surface 210 of the holding member 21 and the upper surface 200 of the base 20. When measuring the thickness of the workpiece 14, the upper surface height measuring device 6 is positioned on the fourth measuring track 244.

[0075] Alternatively, instead of providing a protrusion 23 on the upper surface 200 of the base 20 as described above and using the upper surface of the protrusion 23 as the measuring surface 230, a structure can be adopted in which the upper surface 200 of the base 20 is used as the measuring surface. In this structure, for example, the difference between the height of the upper surface 200 of the base 20 and the height of the holding surface 210 can be calculated in advance, and the height of the holding surface 210 can be identified by adding or subtracting this difference from the measured height of the upper surface 200 of the base 20.

[0076] Furthermore, the retaining member disposed on the upper surface 200 of the base 20 is not limited to the plate-shaped retaining member 21. For example, when grinding a plate-shaped workpiece, grinding can be performed efficiently by disposing of a plate-shaped retaining member on the upper surface 200 of the base 20 instead of the retaining member 21.

[0077] Processing device 1 may also haveFigure 11 The second chuck table 8 is shown instead of the chuck table 2. The second chuck table 8 has a substantially circular plate-shaped second base 84 and a sub-chuck table 80 coupled to the second base 84 in a detachable manner.

[0078] As shown in Figure 12 The second base 84 has a coupling surface 840 coupled to the sub-chuck table 80, and an opening 841 is formed in the center of the coupling surface 840.

[0079] Further, a recessed portion 842 recessed toward the -Z direction side is formed on the radially outermost side of the second base 84, and a plurality of screw holes 843 are formed on the upper surface of the recessed portion 842. The second base 84 is mounted by being threadedly fixed to, for example, the chuck base described above, by means of screws not shown corresponding to the screw holes 843. By detaching the screws, the second base 84 can be detached with respect to the chuck base.

[0080] As shown in Figure 13 The sub-chuck table 80 has a base plate 82 formed in a substantially square shape, and three second holding members 81 in a substantially rectangular parallelepiped shape disposed on the front surface 820 of the base plate 82, as shown in (a). The three second holding members 81 are, for example, all arranged in parallel with the Y axis, and the one in the middle of the three is disposed slightly offset to the radially inner side (+Y direction side) of the second base 84. The upper surface of the second holding member 81 is a holding surface 810 that holds the workpiece 14.

[0081] Further, a protrusion 83 is formed on the front surface 820 of the base plate 82. The protrusion 83 is provided on the inner side of the maximum locus traced by the second holding member 81 when the chuck table 2 rotates with the center 2000 as the axis, and on the outer side of the minimum locus. The upper surface of the protrusion 83 is a measurement surface 830.

[0082] In this configuration, as one of the loci above the holding surface 810 and above the measurement surface 830 of each of the three second holding members 81, a fifth measurement locus 245 is set, and the upper surface height gauge 6 is positioned on the fifth measurement locus 245 when measuring the thickness of the workpiece 14.

[0083] For example, the holding surface 810 and the measurement surface 830 are formed in the same plane, and by measuring the height of the measurement surface 830, the height of the holding surface 810 can be identified.

[0084] Alternatively, the holding surface 810 and the measurement surface 830 can be formed so as not to be coplanar, and a prescribed difference can be provided between the height of the measurement surface 830 and the height of the holding surface 810. In this configuration, the height of the holding surface 810 can be identified by measuring the height of the measurement surface 830 and adding or subtracting the prescribed difference from the measured height of the measurement surface 830.

[0085] Figure 13 (b) shows a state in which the opposite surface of the front surface 820 of the base plate 82, i.e., the joining surface 821, is oriented upward. The joining surface 821 of the base plate 82 is formed with a communication passage 822 that communicates the opening 841 with the holding surface 810. The communication passage 822 has, for example, two rectangular portions that are formed adjacent to each other and a circular portion that is formed so as to span the two rectangular portions.

[0086] When the sub-chuck table 80 is joined with the second base 84, as shown in (a) of FIG. 8, the front surface 820 of the sub-chuck table 80 is oriented toward the +Z direction side, and the second base 84 is placed on the joining surface 840 of the second base 84 so that the opening 841 of the second base 84 coincides with the center portion 8220 of the communication passage 822 of the sub-chuck table 80. Figure 13 Figure 13 Figure 12 As shown in (b) of FIG. 8, the sub-chuck table 80 is placed on the joining surface 840 of the second base 84 so that the opening 841 of the second base 84 coincides with the center portion 8220 of the communication passage 822 of the sub-chuck table 80.

[0087] Further, in a state in which the sub-chuck table 80 is placed on the second base 84, an unillustrated suction unit that is connected to the opening 841 of the joining surface 840 is activated. As a result, the generated suction force is transmitted to the communication passage 822 and joins the sub-chuck table 80 with the second base 84. In addition, the suction force is transmitted to the holding surface 810 of the second holding member 81 provided in the sub-chuck table 80. Therefore, by placing the workpiece 14 on the holding surface 810 in this state, the workpiece 14 can be suction-held to the holding surface 810.

[0088] In addition, an unillustrated groove that extends radially through the opening 841 can be formed in the joining surface 840. In the case in which the groove is formed, the suction force can be more efficiently transmitted from the opening 841 to the joined surface 821 of the sub-chuck table 80, and thus the sub-chuck table 80 can be easily joined with the second base 84.

[0089] In the second-chuck table 8 as well, since the measurement surface that is annular and on which the upper surface height measurer 6 is positioned is not provided, the second-chuck table 8 can be downsized, and thus the machining device itself can be downsized.

[0090] ​​Further, in the related art, the base of the chuck table is replaced in correspondence with the size and number of the workpieces 14, whereas the second chuck table 8 is replaced with the sub-chuck table 80 in correspondence with the size and number of the workpieces 14 to be ground. Thus, the replacement can be easily performed.

[0091] Further, the holding member provided to the sub-chuck table 80 is not limited to the plate-shaped second holding member 81. For example, when the workpieces in a circular plate shape are subjected to grinding processing, the grinding processing can be efficiently performed by providing a holding member in a circular plate shape.

[0092] Further, the processing device 1 is not limited to Figure 1 The grinding device having the grinding wheel 34 shown in the drawing can be, for example, an abrading device having an unillustrated abrasive pad or the like instead of the grinding wheel 34.

Claims

1. A chuck table used in a processing apparatus, The processing apparatus has at least: the chuck table having a holding surface that holds a workpiece; a table rotating section that rotates the chuck table about the center of the chuck table; a processing unit that processes the workpiece held on the holding surface; an upper surface height measurer that measures the height of the upper surface of the workpiece rotated by the table rotating section in a non-contact manner; and a thickness calculating section that calculates the thickness of the workpiece using the value measured by the upper surface height measurer, wherein the chuck table has a base and a holding member provided on the upper surface of the base, the holding surface is the upper surface of the holding member and is located higher than the upper surface of the base, the chuck table has a measurement surface that is formed on the measurement track of the upper surface height measurer relatively moved with respect to the chuck table by rotating the chuck table using the table rotating section in a state where the upper surface height measurer is positioned above the holding surface, and the measurement surface is in the same plane as the holding surface but is formed at a position other than the holding surface.

2. The chuck table according to claim 1, wherein a plurality of the holding surfaces are provided on the measurement track measured by the upper surface height measurer.

3. The chuck table according to claim 1, wherein the chuck table has: a sub-chuck table having the measurement surface and the holding surface; a base having a joint surface that joins the sub-chuck table; an opening formed in the joint surface of the base; and a communication path formed in the joined surface of the sub-chuck table that communicates the opening with the holding surface.

4. A processing apparatus having: a holding unit that installs the chuck table according to claim 1, holds a workpiece on the holding surface, and rotates the chuck table about the center of the holding surface; a thickness measuring unit that measures the thickness of the workpiece; and a processing unit that processes the workpiece to a predetermined specified thickness, wherein the thickness measuring unit has: an upper surface height measurer that measures the height of the upper surface of the workpiece held on the holding surface and the height of the measurement surface in a non-contact manner; and a thickness calculating section that calculates the difference between the height of the upper surface of the workpiece measured on the measurement track of the upper surface height measurer by the rotation of the holding unit and the height of the measurement surface as the thickness of the workpiece.

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