How to set up

Abstract

To enable a setup to be performed in short time without adding a sensor.SOLUTION: A lifting mechanism 60 is lowered from above a wafer 5 held by a holding surface 22, and a height of a grinding mechanism 70 when the undersurface of a grinding stone 77 contacts a top face 6 of the wafer 5 is stored. Further, based on the height, an origin height being a height of the grinding mechanism 70 when the undersurface of the grinding stone 77 contacts the holding surface 22 is obtained. Accordingly, a setup that obtains the origin height of the grinding mechanism 70 can be performed without using a setup block. Consequently, a setup can be conducted in short time. In addition, since a setup sensor is not used, the setup can be implemented with an inexpensive constitution.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a setup method. [Background technology]

[0002] A grinding device that uses a grinding wheel to grind a wafer held by the holding surface of a chuck table is set up to recognize the height of the grinding mechanism to which the grinding wheel is attached when the underside of the grinding wheel is brought into contact with the holding surface, as disclosed in Patent Document 1.

[0003] Such setup may involve the use of a sensor or a setup block, as disclosed in Patent Documents 2 and 3. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-001261 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-135853 [Patent Document 3] Japanese Patent Application Publication No. 2020-199597 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the setup using the setup block, it is time-consuming to change the height of the grinding mechanism and check whether the setup block can be inserted. Also, in the setup using the sensor, the sensor is expensive.

[0006] Therefore, an object of the present invention is to enable setup in a relatively short time without adding any additional sensors. [Means for solving the problem]

[0007] The setup method of the present invention (this setup method) is a setup method using a grinding device comprising a chuck table whose holding surface holds a plate-like object, a grinding mechanism that grinds the plate-like object held on the holding surface with a grinding wheel, a lifting mechanism that moves the grinding mechanism in a direction perpendicular to the holding surface, and a height recognition unit that recognizes the height of the grinding mechanism moved by the lifting mechanism, in which the grinding mechanism is moved by the lifting mechanism and the height of the grinding mechanism when the lower surface of the grinding wheel comes into contact with the holding surface is stored, and the grinding mechanism comprises: a top surface height measuring device which moves together with the grinding mechanism in a direction perpendicular to the holding surface by the lifting mechanism and measures the top surface height of the plate-like object held by the holding surface; lowering the grinding mechanism, starting measurement of the top surface height of the plate-like object by the top surface height measuring device before the bottom surface of the grinding wheel comes into contact with the plate-like object; continuing to lower the grinding mechanism, causing the bottom surface of the grinding wheel to press the top surface of the plate-like object, and recognizing that the change in the measurement value of the top surface height measuring device is no longer a change relative to the change in height of the grinding mechanism; a contact detection unit that detects when the lower surface of the grinding wheel comes into contact with the upper surface of the plate-like object; and, and an elastic portion between the central portion of the lower surface of the plate-like object and the holding surface. or cavity and a storage step of lowering the grinding mechanism equipped with the grinding wheel from above the plate-like object held by the holding surface, and storing the height of the grinding mechanism when it is recognized by the contact detection unit that the lower surface of the grinding wheel has come into contact with the upper surface of the plate-like object held by the holding surface. [Effects of the Invention]

[0008] In this setup method, in the storage step, the lifting mechanism is lowered from above the plate-like object held by the holding surface, and the height of the grinding mechanism when the lower surface of the grinding wheel contacts the upper surface of the plate-like object is stored. Then, based on this height, the origin height, which is the height of the grinding mechanism when the lower surface of the grinding wheel contacts the holding surface, is determined.

[0009] In this way, with this setup method, for example, after replacing the grinding wheel, setup to determine the origin height of the grinding mechanism can be performed without using a setup block. Therefore, setup can be performed in a short time. Furthermore, since no setup sensor is used, setup can be performed with an inexpensive configuration. Furthermore, in the holding step, an elastic part is disposed between the center of the underside of the plate-like object and the holding surface, so that when the underside of the grinding wheel comes into contact with the upper surface of the plate-like object, the elastic part deforms to absorb the impact of the contact, thereby preventing damage to the underside of the grinding wheel. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view showing the configuration of a grinding device. [Figure 2] FIG. 2 is an explanatory diagram showing the configuration of a grinding device. [Figure 3] FIG. 2 is a perspective view showing the configuration of an upper surface height measuring device. [Figure 4] FIG. 2 is a cross-sectional view showing the configuration of an upper surface height measuring device. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. 10 is a schematic diagram showing a storage process. [Figure 9] FIG. 10 is an explanatory diagram showing a storage process. [Figure 10] FIG. 10 is a schematic diagram showing another storage process. [Figure 11] FIG. 10 is a schematic diagram showing another storage process. [Figure 12] 10A and 10B are explanatory views showing other configurations of the holding surface. DETAILED DESCRIPTION OF THE INVENTION

[0011] The grinding apparatus 1 according to this embodiment shown in Fig. 1 is an apparatus for grinding a wafer 5, which is an example of a plate-like object. The wafer 5 is, for example, a circular semiconductor wafer. An upper surface 6 of the wafer 5 is a processing surface to be subjected to grinding.

[0012] In this embodiment, the wafers 5 are handled in the state of a work set 9. The work set 9 is formed by integrating a ring frame 7 having an opening capable of accommodating the wafers 5 with the wafers 5 positioned in the opening of the ring frame 7 using tape 8. In this embodiment, the wafers 5 are ground in the grinding apparatus 1 in the state of this work set 9.

[0013] As shown in FIG. 1, the grinding apparatus 1 includes a rectangular parallelepiped base 10, a column 11 extending upward, and a control unit 3 that controls each member of the grinding apparatus 1.

[0014] An opening 13 is provided on the upper surface side of the base 10. A wafer holding mechanism 30 is disposed within the opening 13. The wafer holding mechanism 30 includes a chuck table 20 whose holding surface 22 holds the wafer 5, a table base 55 that supports the chuck table 20, a table rotation mechanism 50 that rotates the chuck table 20 and the table base 55, and an inclination adjustment mechanism 40 that adjusts the inclination of the chuck table 20.

[0015] 1 and 2, the chuck table 20 includes a porous member 21 as a wafer holding portion, and a frame 23 that houses the porous member 21 so that the upper surface of the porous member 21 is exposed. The upper surface of the porous member 21 is a holding surface 22 that holds the wafer 5 by suction. The holding surface 22 is connected to a suction source 240, which will be described later, to hold the wafer 5 by suction. A frame surface 24, which is the upper surface of the frame 23, is formed flush with the holding surface 22.

[0016] The frame 23 is also provided with four clamps 31 as frame holders for holding the ring frame 7 of the work set 9. The holding surface 22 is configured to hold the wafer 5 above the upper surface of the ring frame 7 held by the clamp 31 .

[0017] A table base 55 that supports the chuck table 20 is provided below the chuck table 20. A table rotation mechanism 50 that rotatably supports the table base 55 is disposed below the table base 55.

[0018] 2, the table rotation mechanism 50 includes a motor 521, a driving pulley 522 attached to the motor 521, a driven pulley 524 connected to the driving pulley 522 via an endless belt 523, and a rotary joint 525 disposed below the driven pulley 524. The driven pulley 524 is supported by a narrow-diameter portion at the bottom of the table base 55.

[0019] In the table rotation mechanism 50, a motor 521 rotates a driving pulley 522, thereby rotating an endless belt 523 and a driven pulley 524. As a result, the table base 55 and the chuck table 20 are rotated as shown by an arrow 502.

[0020] In addition, a tilt adjustment mechanism 40 for adjusting the tilt of the chuck table 20 is provided around the table base 55 .

[0021] The tilt adjustment mechanism 40 includes an internal base 41 arranged below the chuck table 20 , an tilt adjustment shaft 42 , a fixed shaft 43 fixed to the internal base 41 , and an annular member 45 .

[0022] The annular member 45 rotatably supports the table base 55 so as to surround the table base 55 via a connecting portion 46 including a bearing.

[0023] The fixed shaft 43 has its upper end fixed to the lower surface of the annular member 45 and its lower end fixed to the upper surface of the internal base 41 .

[0024] The tilt adjustment shaft 42 is disposed between the internal base 41 and the annular member 45, and can move a part of the annular member 45 up and down along the Z-axis direction, thereby adjusting the tilt of the chuck table 20.

[0025] In the tilt adjustment mechanism 40, the annular member 45 is supported at three locations relative to the internal base 41, with tilt adjustment shafts 42 disposed at one or two of the three locations, and fixed shafts 43 provided at the remaining one or two locations. However, the tilt adjustment mechanism 40 may not be provided with fixed shafts 43, and tilt adjustment shafts 42 may be provided at all three locations described above.

[0026] A flow path 243 is connected to the chuck table 20, and a suction source 240, an air supply source 241, and a water supply source 242 are connected to the flow path 243 via a suction valve 270, an air valve 271, and a water valve 272, respectively.

[0027] This allows the grinding device 1 to supply air or water to the holding surface 22 of the chuck table 20 and to apply suction force from the suction source 240 to the holding surface 22.

[0028] 1, a cover plate 39 that moves along the Y-axis direction together with the chuck table 20 is provided around the periphery of the chuck table 20. A bellows cover 12 that expands and contracts in the Y-axis direction is connected to the cover plate 39. A Y-axis direction moving mechanism 90 is disposed below the wafer holding mechanism 30.

[0029] The Y-axis direction moving mechanism 90 moves the wafer holding mechanism 30 including the chuck table 20 and the grinding mechanism 70 relatively in the Y-axis direction, which is a direction parallel to the holding surface 22. In this embodiment, the Y-axis direction moving mechanism 90 is configured to move the wafer holding mechanism 30 in the Y-axis direction relative to the grinding mechanism 70.

[0030] The Y-axis direction movement mechanism 90 includes a pair of Y-axis guide rails 92 parallel to the Y-axis direction, a Y-axis movement table 95 that slides on these Y-axis guide rails 92, a Y-axis ball screw 93 parallel to the Y-axis guide rails 92, a Y-axis motor 94 connected to the Y-axis ball screw 93, a Y-axis encoder 96 for detecting the rotation angle of the Y-axis motor 94, and a holding base 91 that holds these.

[0031] The Y-axis moving table 95 is slidably installed on the Y-axis guide rail 92. A nut portion (not shown) is fixed to the underside of the Y-axis moving table 95. A Y-axis ball screw 93 is threadedly engaged with this nut portion. The Y-axis motor 94 is connected to one end of the Y-axis ball screw 93.

[0032] In the Y-axis direction moving mechanism 90, a Y-axis motor 94 rotates a Y-axis ball screw 93, thereby moving a Y-axis moving table 95 in the Y-axis direction along a Y-axis guide rail 92. The wafer holding mechanism 30 is placed on the Y-axis moving table 95. Therefore, as the Y-axis moving table 95 moves in the Y-axis direction, the wafer holding mechanism 30 including the chuck table 20 moves in the Y-axis direction.

[0033] In this embodiment, the wafer holding mechanism 30 is moved along the Y-axis direction by a Y-axis direction moving mechanism 90 between a wafer placement area on the -Y direction side for holding the wafer 5 on the holding surface 22 and a grinding area on the +Y direction side where the wafer 5 is ground.

[0034] 1 and 2, a column 11 is erected on the rear (+Y direction side) of the base 10. The column 11 is provided with a grinding mechanism 70 that grinds the wafer 5 and an elevating mechanism 60.

[0035] The lifting mechanism 60 moves the grinding mechanism 70 in the Z-axis direction (grinding feed direction), which is a direction perpendicular to the holding surface 22 of the chuck table 20. The lifting mechanism 60 includes a pair of Z-axis guide rails 61 parallel to the Z-axis direction, a Z-axis moving table 63 that slides on the Z-axis guide rails 61, a Z-axis ball screw 62 parallel to the Z-axis guide rails 61, a Z-axis motor 64, and a Z-axis encoder 65 for detecting the rotation angle of the Z-axis motor 64. A grinding mechanism 70 is attached to the Z-axis moving table 63.

[0036] The Z-axis moving table 63 is slidably installed on the Z-axis guide rail 61 via a slide member 67 (see FIG. 2). A nut portion 68 (see FIG. 2) is fixed to the Z-axis moving table 63. A Z-axis ball screw 62 is threadedly engaged with this nut portion 68. A Z-axis motor 64 is connected to one end of the Z-axis ball screw 62.

[0037] In the lifting mechanism 60, the Z-axis motor 64 rotates the Z-axis ball screw 62, causing the nut portion 68 and the Z-axis moving table 63 to move up and down in the Z-axis direction along the Z-axis guide rail 61. As a result, the grinding mechanism 70 attached to the Z-axis moving table 63 also moves up and down in the Z-axis direction together with the Z-axis moving table 63.

[0038] Furthermore, the Z-axis encoder 65 functions as a height recognition unit, and by detecting the rotation angle of the Z-axis motor 64, recognizes the height of the grinding mechanism 70 moved by the lifting mechanism 60. Note that the Z-axis encoder 65 determines, as the height of the grinding mechanism 70, for example, the height of the nut portion 68 of the lifting mechanism 60, which moves in the Z-axis direction together with the grinding mechanism 70.

[0039] The grinding mechanism 70 grinds the wafer 5 held on the holding surface 22 of the chuck table 20 with a grinding wheel 77. As shown in Figures 1 and 2, the grinding mechanism 70 includes a holder 79 fixed to the Z-axis moving table 63, a spindle housing 71 held by the holder 79, a spindle 72 for rotating the grinding wheel 77, a spindle motor 73 that rotates the spindle 72, a rotation detection unit 78 that detects the rotation speed of the grinding wheel 77, a wheel mount 74 attached to the lower end of the spindle 72, and a grinding wheel 75 supported by the wheel mount 74.

[0040] The spindle 72 extends along the Z-axis direction so as to be perpendicular to the holding surface 22 of the chuck table 20, and is supported by the spindle housing 71 so as to be rotatable about an axis along the extension direction. The spindle motor 73 shown in FIG. 1 is connected to the upper end side of the spindle 72 and rotates the spindle 72.

[0041] The wheel mount 74 is formed in a disk shape and is fixed to the lower end of the spindle 72. The wheel mount 74 supports a grinding wheel 75.

[0042] The grinding wheel 75 is formed so that its outer diameter is approximately the same as the outer diameter of the wheel mount 74. The grinding wheel 75 includes an annular wheel base 76 made of a metal material. A processing water channel 761 is formed inside the wheel base 76 to supply processing water from a water source (not shown) to the grinding wheel 77 (see FIG. 2).

[0043] A plurality of grinding wheels 77 are fixed in an annular arrangement around the entire circumference of the underside of the wheel base 76. The grinding wheels 77 are rotated around their centers by the spindle motor 73 together with the spindle 72, and grind the top surface 6 of the wafer 5 held on the chuck table 20.

[0044] The grinding apparatus 1 also has an upper surface height measuring device 80 that measures the height of the upper surface of the wafer 5 held by the holding surface 22 of the chuck table 20. The upper surface height measuring device 80 is attached to the holder 79 of the grinding mechanism 70 by a mounting member 81, and is thereby disposed in the grinding mechanism 70. As a result, the upper surface height measuring device 80 is moved by the lifting mechanism 60 together with the grinding mechanism 70 in the Z-axis direction, which is a direction perpendicular to the holding surface 22.

[0045] The top surface height measuring device 80 may be configured to move in the Z-axis direction together with the grinding mechanism 70 by the lifting mechanism 60, and may, for example, be provided in a part of the lifting mechanism 60 that moves up and down together with the grinding mechanism 70.

[0046] Furthermore, the grinding apparatus 1 is provided with a contact or non-contact holding surface height measuring device 83 for measuring the height of the holding surface 22 of the chuck table 20. The holding surface height measuring device 83 is disposed on the side of the opening 13 in the base 10.

[0047] Here, the configuration of the upper surface height measuring device 80 will be described. The top surface height measuring device 80 shown in Figures 3 and 4 includes a probe 110 whose tip comes into contact with the top surface 6 of the wafer 5, a housing 112 serving as a guide unit that supports the probe 110 so that it can move up and down freely under its own weight, and a scale 114 for reading the height position of the probe 110.

[0048] In this embodiment, the top surface height measuring instrument 80 further includes a moving mechanism 113 that moves the probe 110 along the Z-axis direction, a detection mechanism 115 that reads the graduations 140 on the scale 114, an exhaust port 116 and a throttle valve 117 for exhaust, and a case 101 as a housing.

[0049] The probe 110 extends in the Z-axis direction, which is a direction perpendicular to the holding surface 22. The upper end of the probe 110 is connected to the connecting member 103.

[0050] Case 101 is supported from above by mounting member 81 shown in Figures 1 and 2. Probe 110 is formed in the shape of a quadrangular prism and penetrates case 101, with the tip of probe 110 protruding downward from the bottom surface of case 101, as shown in Figures 3 and 4.

[0051] The housing 112 surrounds the side surface 111 of the probe 110 and supports the probe 110 in a non-contact manner so as to be movable in the Z-axis direction perpendicular to the holding surface 22 .

[0052] That is, the housing 112 has a tube 120 that houses the probe 110. The tube 120 is disposed on the mounting surface 102 inside the case 101. The tube 120 has a hole with a rectangular cross section formed therein to accommodate the probe 110, so that the hole corresponds to the shape of the probe 110. The tube 120 is configured so that the probe 110 can be inserted into this hole and the periphery of the probe 110 can be supported in a non-contact manner.

[0053] The cylinder 120 also has an inner support surface 121 and a plurality of nozzles 122 provided on the support surface 121. The support surface 121 faces the side surface 111 of the probe 110 at an equal distance from the side surface 111.

[0054] As shown in FIG. 4, the cylinder 120 also includes an inlet 123 connected to an air supply source (not shown), and flow paths 124 that connect the inlet 123 to each of the outlets 122 .

[0055] In the housing 112, with the support surface 121 of the tube 120 facing the side surface 111 of the probe 110, air supplied to the inlet 123 is blown onto the side surface 111 of the probe 110 via the flow path 124 and the outlet 122 of the support surface 121. This allows the housing 112 to support the probe 110 with air interposed between the side surface 111 of the probe 110 and the support surface 121.

[0056] Furthermore, in housing 112, air that has flowed into tube 120 is discharged from upper exhaust port 125 and lower exhaust port 126 of tube 120. With this structure, housing 112 can support probe 110 in a non-contact manner so that probe 110 can move in the Z-axis direction.

[0057] The exhaust port 116 is an exhaust port for exhausting air exhausted from the housing 112 into the case 101 to the outside of the case 101. A throttle valve 117 connected to the exhaust port 116 adjusts the amount of exhaust to adjust the pressure inside the case 101, and thereby adjusts the pressing pressure of the probe 110 against the upper surface 6 of the wafer 5.

[0058] The movement mechanism 113 is disposed near the probe 110 on the mounting surface 102 of the case 101. The movement mechanism 113 includes a cylinder 130 and a piston 131. The piston 131 moves inside the cylinder 130 in the Z-axis direction, which is parallel to the axial direction of the probe 110.

[0059] Furthermore, the movement mechanism 113 is provided with inlets 132 and 133 in the cylinder 130 for allowing air to flow into the interior thereof. The movement mechanism 113 having such a structure can move the probe 110 in the Z-axis direction via the connecting member 103 by linearly moving the piston 131 in the Z-axis direction.

[0060] That is, when the probe 110 is raised in the +Z direction by the movement mechanism 113, air from an air supply source (not shown) is supplied into the cylinder 130 via the inlet 132. This causes the piston 131 to rise inside the cylinder 130. Then, the piston 131 comes into contact with the connecting member 103 to raise the connecting member 103, causing the probe 110 connected to the connecting member 103 to rise.

[0061] On the other hand, when the probe 110 is lowered by the movement mechanism 113, air is supplied from an air supply source (not shown) into the cylinder 130 via the inlet 133. This causes the piston 131 to lower inside the cylinder 130. Accordingly, the probe 110 is lowered by the weight of the probe 110 and the connecting member 103 connected to the probe 110.

[0062] Moreover, the moving mechanism 113 can adjust the descending speed of the piston 131 by adjusting the amount of air flowing in from the inlet 133, thereby limiting the descending speed of the probe 110. Then, the moving mechanism 113 can lower the probe 110 until the tip of the probe 110 comes into contact with a surface below the probe 110, for example, the top surface 6 of the wafer 5 held on the holding surface 22 of the chuck table 20.

[0063] 3 and 4, scale 114 hangs down from the end of connecting member 103 and is disposed parallel to the Z-axis direction, which is the extension direction of probe 110. Scale 114 is connected to probe 110 via connecting member 103, and moves in the Z-axis direction together with probe 110.

[0064] The detection mechanism 115 is attached to an end of the case 101. The detection mechanism 115 includes a support plate 150 extending in the Z-axis direction, and a detection unit 151 disposed at the tip of the support plate 150. The detection unit 151 faces the graduations 140 of the scale 114 and reads the graduations 140. In this way, the detection unit 151 can detect the height of the probe 110 in contact with the upper surface 6 of the wafer 5 by reading the graduations 140 of the scale 114 which moves in the Z-axis direction together with the probe 110.

[0065] 1 and 2 includes a CPU, memory, etc., and controls each component of the grinding apparatus 1 to set up the grinding mechanism 70 and to grind the wafer 5. The control unit 3 also functions as a contact detection unit that detects when the lower surface of the grinding wheel 77 in the grinding mechanism 70 comes into contact with the upper surface 6 of the wafer 5 held on the holding surface 22 of the chuck table 20. The control unit 3 is also connected to a memory unit 4 that stores the measured value of the height of the grinding mechanism 70, etc.

[0066] The following describes a method for setting up the grinding mechanism 70. This setup method is performed, for example, after replacing the grinding wheel 77. In this setup method, the lifting mechanism 60 moves the grinding mechanism 70, and the height of the grinding mechanism 70 when the lower surface of the grinding wheel 77 comes into contact with the holding surface 22 of the chuck table 20 is stored.

[0067] [Holding process] In this step, the holding surface 22 of the chuck table 20 holds the wafer 5 so that the elastic portion is located between the central portion of the lower surface of the wafer 5, which is a plate-like object, and the holding surface 22 of the chuck table 20.

[0068] Specifically, as shown in Fig. 2, an operator first places the wafer 5 of the work set 9 on the holding surface 22 of the chuck table 20 via the tape 8, and supports the ring frame 7 of the work set 9 with the clamp 31. In this way, the work set 9 including the wafer 5 is held by the chuck table 20.

[0069] Next, the control unit 3 uses the Y-axis direction movement mechanism 90 shown in Figure 1 to adjust the position of the chuck table 20 so that the grinding wheel 77 is positioned at the center of the wafer 5 held on the holding surface 22 of the chuck table 20.

[0070] Thereafter, the control unit 3 uses the lifting mechanism 60 to lower the grinding mechanism 70 equipped with the grinding wheel 77 and the upper surface height measuring device 80 from above the wafer 5 held by the holding surface 22. At this time, the control unit 3 keeps the probe 110 of the upper surface height measuring device 80 in a state where it hangs down from the case 101 by its own weight.

[0071] In this way, when the probe 110 is suspended from the case 101 by its own weight and the grinding mechanism 70 and the top surface height measuring device 80 are lowered, the tip of the probe 110 comes into contact with the top surface 6 of the wafer 5 before the bottom surface of the grinding wheel 77, as shown in FIG. 5.

[0072] When the grinding mechanism 70 and the top surface height measuring device 80 are lowered and the tip of the probe 110 comes into contact with the top surface 6 of the wafer 5, the probe 110 rises in the +Z direction relative to the case 101 (see FIG. 4), and the change in the height of the probe 110 in the +Z direction is detected by the detection unit 151. By detecting this change in the height of the probe 110 in the +Z direction, the control unit 3 detects that the tip of the probe 110 has come into contact with the top surface 6 of the wafer 5, and stops the lowering of the grinding mechanism 70 and the top surface height measuring device 80 by the lifting mechanism 60, and acquires the height of the probe 110 detected by the detection unit 151 of the top surface height measuring device 80 as a first measurement value A1.

[0073] Next, the control unit 3 controls the air valve 271 (see FIG. 2) to connect the air supply source 241 to the holding surface 22 of the chuck table 20, thereby starting air blowing from the holding surface 22. As a result, air from the holding surface 22 of the chuck table 20 is blown onto the tape 8 of the work set 9 facing the holding surface 22. As a result, the tape 8 and the wafer 5 are lifted in the +Z direction, and a cavity 210 serving as an elastic portion is formed between the holding surface 22 and the central portion 51 of the underside of the wafer 5, as shown in FIG. The elastic portion may be formed by jetting water from the holding surface 22 . Thus, in the holding process, the holding surface 22 holds the wafer 5 so that a cavity 210 as an elastic portion is formed and positioned between the central portion 51 of the underside of the wafer 5 and the holding surface 22, as shown in Figures 6 and 7.

[0074] 6, the formation of cavity 210 causes probe 110, which is in contact with top surface 6 of wafer 5, to rise in the +Z direction. Control unit 3 detects the height of the raised probe 110 using detection unit 151 of top surface height measuring device 80 and acquires the height as second measurement value A2. Furthermore, control unit 3 calculates the difference (|A1-A2|) between first measurement value A1 and second measurement value A2, and recognizes this difference as thickness V1 of cavity 210. In addition, when the cavity 210 is formed and the probe 110 is raised, the probe 110 is suspended from the case 101 so that the lower end of the probe 110 is lower than the lower surface of the grinding wheel 77 so that the lower surface of the grinding wheel 77 does not come into contact with the upper surface 6 of the wafer 5.

[0075] [Memory process] Thereafter, the control unit 3 uses the lifting mechanism 60 to resume lowering the grinding mechanism 70 from above the wafer 5 held by the holding surface 22 so that the lower surface of the grinding wheel 77 comes into contact with the upper surface 6 of the wafer 5.

[0076] As described above, at this time, the tip of the probe 110 comes into contact with the upper surface 6 of the wafer 5 before the lower surface of the grinding wheel 77. Therefore, the control unit 3 starts measuring the upper surface height of the upper surface 6 of the wafer 5 using the upper surface height measuring device 80 before the lower surface of the grinding wheel 77 comes into contact with the wafer 5.

[0077] The control unit 3 uses the lifting mechanism 60 to continuously lower the grinding mechanism 70 as shown by arrow 401 in FIG. 8 . As a result, as shown in FIGS. 8 and 9 , the probe 110 rises relative to the case 101 as the grinding mechanism 70 lowers, and the height of the probe 110 detected by the detection unit 151 changes in the +Z direction (see arrow 400 in FIG. 8 ) until the lower surface of the grinding wheel 77 contacts and presses against the upper surface 6 of the wafer 5. That is, the measurement value of the upper surface height measuring device 80 changes in the +Z direction by the same amount as the change in the height of the grinding mechanism 70 in the −Z direction per unit time as recognized by the Z-axis encoder 65 until the lower surface of the grinding wheel 77 contacts the upper surface 6 of the wafer 5. Therefore, the change in the measurement value of the upper surface height measuring device 80 is a change relative to the change in the height of the grinding mechanism 70.

[0078] On the other hand, after the lower surface of the grinding wheel 77 comes into contact with the upper surface 6 of the wafer 5, the grinding wheel 77 crushes the cavity 210 as the grinding mechanism 70 descends, and the upper surface 6 of the wafer 5 begins to descend in the -Z direction. As a result, the tip of the probe 110 in contact with the upper surface 6 also begins to descend in the -Z direction. Therefore, as the grinding mechanism 70 descends, the probe 110, which had been rising relative to the case 101, descends. As a result, the amount of change in the measurement value of the upper surface height measuring device 80 in the +Z direction per unit time is no longer the same as the amount of change in the height of the grinding mechanism 70 in the -Z direction per unit time. In other words, the change in the measurement value of the upper surface height measuring device 80 is no longer a change relative to the change in the height of the grinding mechanism 70.

[0079] Then, the control unit 3 recognizes that the lower surface of the grinding wheel 77 has pressed against the upper surface 6 of the wafer 5 and that the change in the measurement value of the upper surface height measuring device 80 is no longer a change relative to the change in the height of the grinding mechanism 70, thereby detecting that the lower surface of the grinding wheel 77 has come into contact with the upper surface 6 of the wafer 5 held on the holding surface 22. At this time, the control unit 3 stops the lowering of the grinding mechanism 70 by the lifting mechanism 60, acquires the value of the height of the grinding mechanism 70 recognized by the Z-axis encoder 65 as a first height Z1 (see FIG. 8), and stores it in the memory of the control unit 3 and / or the storage unit 4. Note that FIG. 2 shows a virtual scale 200 indicating the height of the grinding mechanism 70 recognized by the Z-axis encoder 65. Thereafter, the control unit 3 uses the lifting mechanism 60 to raise the grinding mechanism 70.

[0080] Next, the control unit 3 calculates the origin height, which is the height of the grinding mechanism 70 when the lower surface of the grinding wheel 77 contacts the holding surface 22 of the chuck table 20, based on the acquired first height Z1 of the lifting mechanism 60.

[0081] That is, the control unit 3 calculates the origin height Z0 of the grinding mechanism 70 as follows by subtracting the thickness V1 of the cavity 210 described above, as well as the thickness W1 of the wafer 5 and the thickness T1 of the tape 8 (see Figures 8 and 9) that are known in advance, from the first height Z1 of the grinding mechanism 70, as shown in the following equation (1): Z0 = Z1 - V1 - W1 - T1 … (1)

[0082] 8 and 9, in this step, when the lower surface of the grinding wheel 77 comes into contact with the upper surface 6 of the wafer 5 and the grinding wheel 77 begins to crush the cavity 210, the grinding mechanism 70 stops descending and attains the first height Z1. Therefore, the thickness of the cavity 210 remains substantially unchanged. Therefore, when the lower surface of the grinding wheel 77 comes into contact with the upper surface 6 of the wafer 5 and the grinding mechanism 70 attains the first height Z1, the wafer 5, tape 8, and cavity 210 are present between the lower surface of the grinding wheel 77 and the holding surface 22.

[0083] Therefore, the control unit 3 can obtain the origin height Z0, which is the height of the grinding mechanism 70 when the lower surface of the grinding wheel 77 contacts the holding surface 22 of the chuck table 20, by subtracting the thicknesses of the wafer 5, tape 8, and cavity 210 from the first height Z1 using the calculation shown in equation (1) above. The control unit 3 stores the obtained origin height Z0 of the grinding mechanism 70 in the memory of the control unit 3 and / or the storage unit 4.

[0084] As described above, in this embodiment, in the storage step, the lifting mechanism 60 is lowered from above the wafer 5 held by the holding surface 22, and the height of the grinding mechanism 70 when the lower surface of the grinding wheel 77 comes into contact with the upper surface 6 of the wafer 5 is stored. Then, the origin height of the grinding mechanism 70 is determined based on this height.

[0085] As described above, in this embodiment, for example, after replacing the grinding wheel 77, the setup for determining the origin height of the grinding mechanism 70 can be performed without using a setup block. Therefore, the setup can be performed in a short time. Furthermore, by performing the setup using the wafer 5, the wafer 5 can be ground immediately after the setup. Therefore, the work efficiency from the setup to the grinding process can be improved. Furthermore, since no setup sensor is used, setup can be performed with an inexpensive configuration.

[0086] Furthermore, in this embodiment, in the holding step, a cavity 210 is formed as an elastic portion between the central portion 51 of the lower surface of the wafer 5 and the holding surface 22. Therefore, when the lower surface of the grinding wheel 77 comes into contact with the upper surface 6 of the wafer 5, the cavity 210 deforms to absorb the impact of the contact, thereby preventing the lower surface of the grinding wheel 77 from being damaged.

[0087] When the descent of the grinding mechanism 70 is stopped and the first height Z1 is acquired, the cavity 210 may be significantly crushed by the grinding wheel 77, causing a significant change in the thickness V1 of the cavity 210, as shown in Fig. 10. In this case, the control unit 3 corrects V1 according to the amount of change in the thickness of the cavity 210, and then performs the calculation shown in the above equation (1).

[0088] 11, when the descent of the grinding mechanism 70 is stopped and the first height Z1 is obtained, the cavity 210 may be completely crushed by the grinding wheel 77, causing the tape 8 to come into contact with the holding surface 22. In this case, the origin height Z0 of the grinding mechanism 70 is calculated by using the following equation (2) instead of the above-mentioned equation (1) by subtracting the thickness W1 of the wafer 5 and the thickness T1 of the tape 8, which are known in advance, from the first height Z1, which is the height of the grinding mechanism 70 when the lower surface of the grinding wheel 77 comes into contact with the upper surface 6 of the wafer 5. Z0 = Z1 - W1 - T1 … (2)

[0089] Furthermore, after obtaining the first height Z1 so that the thickness of the cavity 210 does not change, the grinding mechanism 70 is resumed to descend, and when the cavity 210 is completely crushed by the grinding wheel 77, the grinding mechanism 70 is stopped, and the second height Z2 of the grinding mechanism 70 shown in FIG. 11 is obtained, and the thickness V1 of the cavity 210 can be obtained by subtracting the second height Z2 from the first height Z1 as shown in the following equation (3). V1 = |(Z1 - Z2)| … (3) It is detected that the cavity 210 has been completely crushed when the amount of change in the height of the grinding mechanism 70 in the -Z direction per unit time of the upper surface height measuring device 80 in the +Z direction becomes equal to the amount of change in the height of the grinding mechanism 70 in the -Z direction per unit time.

[0090] In this embodiment, the control unit 3, which functions as a contact detection unit, detects that the lower surface of the grinding wheel 77 has come into contact with the upper surface 6 of the wafer 5 by detecting that the measurement value of the upper surface height measuring device 80 has stopped changing, and determines the first height Z1 of the grinding mechanism 70 at that time.

[0091] 1, the control unit 3 may detect that the lower surface of the grinding wheel 77 has come into contact with the upper surface 6 of the wafer 5. As described above, the rotation detection unit 78 detects the rotation speed of the grinding wheel 77. In this embodiment, the rotation detection unit 78 detects the rotation speed of the spindle 72 to which the grinding wheel 77 is attached as the rotation speed of the grinding wheel 77.

[0092] In this configuration, during the storage process, when the grinding mechanism 70 is lowered from above the wafer 5 held by the holding surface 22, the control unit 3 controls the spindle motor 73 to rotate the spindle 72 and the grinding wheel 77 attached to the tip of the spindle 72, and detects the rotation speed of the spindle 72 using the rotation detection unit 78.

[0093] In this case, the control unit 3 stops the output of the spindle motor 73 before the lower surface of the grinding wheel 77 comes into contact with the upper surface 6 of the wafer 5, and causes the spindle 72 to rotate by inertia.

[0094] Thereafter, as the grinding mechanism 70 descends, the lower surface of the grinding wheel 77 comes into contact with and presses against the upper surface 6 of the wafer 5, and the frictional resistance between the grinding wheel 77 and the upper surface 6 of the wafer 5 causes the rotation speed of the spindle 72 detected by the rotation detection unit 78 to slow down. Then, the control unit 3 detects that the lower surface of the grinding wheel 77 has come into contact with the upper surface 6 of the wafer 5 due to the slowdown in the rotation speed of the spindle 72 detected by the rotation detection unit 78, and at this time, stops the lowering of the grinding mechanism 70 by the lifting mechanism 60, and can acquire the height value of the grinding mechanism 70 recognized by the Z-axis encoder 65 as the first height Z1. Even with this configuration, when the lower surface of the rotating grinding wheel 77 comes into contact with the upper surface 6 of the wafer 5, the cavity 210 deforms to absorb the impact of the contact, thereby preventing damage to the lower surface of the grinding wheel 77.

[0095] The rotation detector 78 may also be configured to detect the power consumed by the spindle motor 73 to rotate the spindle 72. In this case, the spindle 72 rotates freely before the lower surface of the grinding wheel 77 comes into contact with the upper surface 6 of the wafer 5, and therefore the power consumption of the spindle motor 73 detected by the rotation detector 78 is relatively small.

[0096] On the other hand, when the lower surface of the grinding wheel 77 comes into contact with the upper surface 6 of the wafer 5 and presses against the upper surface 6, the power consumption of the spindle motor 73 detected by the rotation detection unit 78 becomes relatively large due to the frictional resistance described above. Then, the control unit 3 can detect that the lower surface of the grinding wheel 77 has come into contact with the upper surface 6 of the wafer 5 based on the increase in power consumption detected by the rotation detection unit 78. The rotation detector 78 may be configured to detect the load current value of the spindle motor 73 as the power consumption of the spindle motor 73 .

[0097] Furthermore, rotation detection unit 78 may include a disk with a slit formed therein provided at the upper end of spindle 72, and a sensor that detects the slit in the disk (both not shown). In this case, rotation detection unit 78 can determine the rotation speed of spindle 72 by using the sensor to detect the slit in the disk that rotates together with spindle 72.

[0098] In this embodiment, a cavity 210 is formed as an elastic portion disposed between the holding surface 22 and the central portion 51 of the underside of the wafer 5. In this regard, instead of the cavity 210, a sponge, an air bag, or the like may be disposed as the elastic portion between the tape 8 and the holding surface 22. In this case, in the holding step, the work set 9 including the wafer 5 is held by the chuck table 20 without forming the cavity 210 between the holding surface 22 and the central portion 51 of the underside of the wafer 5. In this case, the control unit 3 acquires the first height Z1 in the storage process, and then calculates the origin height Z0 of the grinding mechanism 70 by using the thickness of an elastic part such as a sponge or airbag instead of the thickness V1 of the cavity 210 in the above-mentioned equation (1).

[0099] Alternatively, a relatively thick and elastic tape may be used as the tape 8 of the work set 9, so that the tape 8 serves as an elastic portion. In this case as well, the work set 9 including the wafer 5 is held by the chuck table 20 in the holding step without forming a cavity 210 between the holding surface 22 and the central portion 51 of the underside of the wafer 5. In this case, after acquiring the first height Z1 in the storage process, the control unit 3 uses the above equation (2) instead of the above equation (1) to calculate the origin height Z0 of the grinding mechanism 70 by subtracting the thickness W1 of the wafer 5 and the thickness T1 of the tape 8, which are known in advance, from the first height Z1, which is the height of the grinding mechanism 70 when the lower surface of the grinding wheel 77 contacts the upper surface 6 of the wafer 5.

[0100] In addition, in this embodiment, the wafer 5 is handled in the form of a work set 9, and the ring frame 7 of the work set 9 is supported by the clamp 31 of the chuck table 20, so that the work set 9 including the wafer 5 is held by the chuck table 20. In this regard, it is also possible to handle the wafer 5 without placing it in the state of the work set 9. In this case, for example, as shown in FIG. 12 , the holding surface 22 of the chuck table 20 may include a central holding surface 221 and an annular holding surface 222.

[0101] In this configuration, in the holding process, the control unit 3 controls the suction valve 270 (see Figure 2) to connect the suction source 240 to the annular holding surface 222, thereby suction-holding, for example, the outer peripheral portion of the wafer 5 having the protective tape 15 thereon, by the annular holding surface 222.

[0102] The control unit 3 further controls the air valve 271 (see FIG. 2) to connect the air supply source 241 to the central holding surface 221, thereby ejecting air from the central holding surface 221. This allows a cavity 210 serving as an elastic portion to be formed between the holding surface 22 and the central portion 51 of the underside of the wafer 5.

[0103] In this case, the control unit 3 calculates the origin height Z0 of the grinding mechanism 70, for example, by using the following equation (4) instead of the above-mentioned equation (1) to subtract the thickness V1 of the cavity 210, as well as the thickness W1 of the wafer 5 and the thickness H1 of the protective tape 15, which are known in advance, from the first height Z1 of the grinding mechanism 70. Z0 = Z1 - V1 - W1 - H1 … (4)

[0104] In this embodiment, the wafer 5 is used as the plate-like object held on the holding surface 22 for setup. In this regard, instead of the wafer 5, another plate-like object such as a dresser board may be held on the holding surface 22.

[0105] 1 may be used as a height recognition unit that recognizes the height of grinding mechanism 70 instead of Z-axis encoder 65. Linear scale 25 includes reading unit 26 that is provided on Z-axis moving table 63 of lifting mechanism 60 and moves in the Z-axis direction together with grinding mechanism 70, and scale unit 27 that is provided on the surface of Z-axis guide rail 61. Reading unit 26 reads the scale on scale unit 27, thereby making it possible to recognize the height of grinding mechanism 70 that is moved in the Z-axis direction by lifting mechanism 60. [Explanation of symbols]

[0106] 1: Grinding device, 3: Control unit, 4: Memory unit, 5: Wafer, 6: Upper surface, 7: Ring frame, 8: Tape, 9: Work set, 10: Base, 11: Column, 12: bellows cover, 13: opening, 15: protective tape, 20: chuck table, 21: porous member, 22: holding surface, 23: frame, 24: frame surface, 25: Linear scale, 26: Reading unit, 27: Scale unit, 30: Wafer holding mechanism, 31: clamp, 39: cover plate, 40: tilt adjustment mechanism, 41: internal base, 42: tilt adjustment shaft, 43: fixed shaft, 45: annular member, 46: connecting portion, 50: table rotation mechanism, 51: central portion, 55: table base, 60: lifting mechanism, 61: Z-axis guide rail, 62: Z-axis ball screw, 63: Z-axis moving table, 64: Z-axis motor, 65: Z-axis encoder, 67: slide member, 68: nut portion, 70: grinding mechanism, 71: spindle housing, 72: spindle, 73: spindle motor, 74: wheel mount, 75: grinding wheel, 76: Wheel base, 77: Grinding wheel, 78: Rotation detection unit, 79: Holder, 80: Upper surface height measuring device, 81: Mounting member, 83: Holding surface height measuring device, 90: Y-axis direction movement mechanism, 91: support base, 92: Y-axis guide rail, 93: Y-axis ball screw, 94: Y-axis motor, 95: Y-axis moving table, 96: Y-axis encoder, 101: case, 102: mounting surface, 103: connecting member, 110: probe, 111: side surface, 112: housing, 113: moving mechanism, 114: scale, 115: detection mechanism, 116: exhaust port, 117: throttle valve, 120: cylinder, 121: support surface, 122: nozzle, 123: inlet, 124: flow path, 125: upper exhaust port, 126: lower exhaust port, 130: cylinder, 131: piston, 132: inlet, 133: inlet, 140: scale, 150: Support plate, 151: Detection unit, 200: Scale, 210: Cavity, 221: central holding surface, 222: annular holding surface, 240: suction source, 241: air supply source, 242: water supply source, 243: flow path, 270: suction valve, 271: air valve, 272: water valve, 502: arrow, 521: motor, 522: driving pulley, 523: endless belt, 524: driven pulley, 525: Rotary joint, 761: Processing waterway

Claims

[Claim 1] A setup method using a grinding device including a chuck table whose holding surface holds a plate-like object, a grinding mechanism that grinds the plate-like object held on the holding surface with a grinding wheel, an elevation mechanism that moves the grinding mechanism in a direction perpendicular to the holding surface, and a height recognition unit that recognizes the height of the grinding mechanism moved by the elevation mechanism, the method comprising: moving the grinding mechanism with the elevation mechanism; and storing the height of the grinding mechanism when the lower surface of the grinding wheel comes into contact with the holding surface, The grinding mechanism includes: an upper surface height measuring device that moves together with the grinding mechanism in a direction perpendicular to the holding surface by the lifting mechanism and measures the height of the upper surface of the plate-like object held by the holding surface; a contact detection unit that detects that the lower surface of the grinding wheel has come into contact with the upper surface of the plate-like object by lowering the grinding mechanism and starting measurement of the upper surface height measuring device before the lower surface of the grinding wheel comes into contact with the plate-like object, and then continues lowering the grinding mechanism so that the lower surface of the grinding wheel presses the upper surface of the plate-like object, and by recognizing that a change in the measurement value of the upper surface height measuring device is no longer a change relative to a change in the height of the grinding mechanism, a holding step in which the holding surface holds the plate-like object so that an elastic portion or a cavity is disposed between the holding surface and a central portion of the lower surface of the plate-like object; a storage step of lowering the grinding mechanism equipped with the grinding stone from above the plate-like object held by the holding surface, and storing the height of the grinding mechanism when it is recognized by the contact detection unit that the lower surface of the grinding stone has come into contact with the upper surface of the plate-like object held by the holding surface. How to set it up.

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