Grinding equipment

Abstract

Adjust the tilt of the setup table to match the tilt of the grinding wheel. [Solution] When the table 93 is not in contact with the grinding wheel 77, a coil spring 913 keeps the concave spherical surface 931 of the table 93 and the convex spherical surface 912 of the block 91 apart from each other. This avoids contact friction between the concave spherical surface 931 and the convex spherical surface 912, allowing the table 93 to tilt easily. Therefore, when the lower surface of the tilted grinding wheel 77 abuts against the upper surface of the table 93, the tilt of the table 93 changes to follow the tilt of the grinding wheel 77, and the upper surface of the table 93 and the lower surface of the grinding wheel 77 become parallel. This makes it possible to reduce the error in the desired origin height position of the grinding mechanism 70.

Description

[Technical Field]

[0001] The present invention relates to a grinding device. [Background technology]

[0002] In a grinding device that uses a grinding wheel to grind a wafer held on a chuck table, as disclosed in Patent Document 1, a setup unit is placed between the lower surface of the grinding wheel and the upper surface of the chuck table, and the height of the grinding mechanism when it is in contact with the setup unit is stored. Based on this height, the height position (origin height position) of the grinding mechanism when the lower surface of the grinding wheel contacts the upper surface of the chuck table is calculated. Furthermore, using the calculation result, the grinding wheel is positioned above the upper surface of the wafer at the start of grinding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-144327 Summary of the Invention [Problem to be solved by the invention]

[0004] In the setup unit, the contact plate (table) that the underside of the grinding wheel comes into contact with is supported by support balls (support parts), which changes the inclination of the contact plate to match the inclination of the grinding wheel, making the contact plate and the underside of the grinding wheel parallel.

[0005] However, with this configuration, the inclination of the contact plate cannot be changed sufficiently due to contact friction between the support ball and the contact plate, and the contact plate and the underside of the grinding wheel are not parallel, which can cause errors in the calculation result of the origin height position. For this reason, if the calculation result is used, the air cut time at the start of grinding may be longer.

[0006] Therefore, an object of the present invention is to appropriately adjust the inclination of the contact plate (table) of the setup unit so that it follows the inclination of the grinding wheel. [Means for solving the problem]

[0007] The grinding apparatus of the present invention (the present grinding apparatus) is a grinding apparatus comprising: a chuck table having a base outside a holding surface that holds a wafer, the upper surface of which is at a height related to the holding surface; a grinding mechanism that grinds the wafer with the underside of a grinding wheel; a lifting mechanism that raises and lowers the grinding mechanism; and a setup unit that is disposed between the upper surface of the base and the underside of the grinding wheel and that detects the height position of the grinding mechanism when the underside of the grinding wheel comes into contact with the holding surface, the setup unit comprising a table, a table support portion that supports the table so as to be able to rise and fall, a contact portion that is disposed below the table and comes into contact with the upper surface of the base, and a setup unit that is connected to the table support portion and supports the contact portion so as to be able to rise and fall. a contact support section for supporting the table support section and the contact support section so that they can be raised and lowered; a lifting support section for supporting the table support section and the contact support section so that they can be raised and lowered; and a horizontal movement mechanism for moving the table support section and the contact support section horizontally within a range from the top of the base to the outside of the chuck table, wherein the table has a first spherical surface on its underside, and the table support section has a second spherical surface for supporting the first spherical surface of the table pressed down by the grinding wheel of the grinding mechanism which is lowered by the lifting mechanism, and levitation means for keeping the first spherical surface and the second spherical surface of the table separated from each other when the table is not pressed down by the grinding wheel. [Effects of the Invention]

[0008] In this grinding device, when the table is not being pressed down by the grinding wheel, the levitation means keeps the first spherical surface of the table and the second spherical surface of the table support apart from each other. This prevents contact friction between the first and second spherical surfaces, making it easier for the table to tilt relative to the table support.

[0009] Therefore, in this grinding device, when the tilted underside of the grinding wheel abuts against the top surface of the table, the tilt of the table changes to match the tilt of the grinding wheel, so that the top surface of the table and the bottom surface of the grinding wheel become parallel. Then, as the grinding wheel descends, the table descends, so that the first spherical surface contacts the second spherical surface, and the table, table support, abutment support, and abutment part become one unit. In this state, the abutment part abuts against the top surface of the base of the chuck table, and at this point, the height position of the grinding mechanism (origin height position) is determined.

[0010] In this way, the present grinding apparatus can appropriately adjust the tilt of the table to match the tilt of the grinding wheel. Therefore, in this grinding apparatus, when determining the origin height position of the grinding mechanism, the bottom surface of the grinding wheel and the top surface of the table can be made parallel to each other, thereby reducing the error in the determined origin height position of the grinding mechanism. This makes it possible to prevent, for example, an increase in air cutting time during wafer grinding. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view showing the configuration of a grinding device. [Figure 2] FIG. 2 is a cross-sectional view showing the configuration of a grinding device. [Figure 3] FIG. 2 is a cross-sectional view showing the configuration of a setup unit. [Figure 4] FIG. 10 is a cross-sectional view showing a setup operation. [Figure 5] FIG. 10 is a cross-sectional view showing a setup operation. [Figure 6] FIG. 10 is a cross-sectional view showing a setup operation. [Figure 7] FIG. 10 is a cross-sectional view showing the configuration of another setup unit. [Figure 8] FIG. 10 is a cross-sectional view showing a setup operation. [Figure 9] FIG. 10 is a cross-sectional view showing the configuration of yet another setup unit. DETAILED DESCRIPTION OF THE INVENTION

[0012] As shown in FIG. 1, a grinding apparatus 1 according to this embodiment is an apparatus that grinds a wafer 100 as a workpiece with an annular grinding wheel.

[0013] Wafer 100 is, for example, a circular semiconductor wafer, and includes a front surface 101 and a back surface 102. Front surface 101 of wafer 100, which faces downward in FIG. 1, holds multiple devices and is protected by the attachment of protective tape 103. Back surface 102 of wafer 100 is the grinding surface that is subjected to the grinding process.

[0014] As shown in FIG. 1, the grinding device 1 includes a rectangular parallelepiped device base 2, a column 3 extending upward, and a control unit 7 that controls each component of the grinding device 1.

[0015] An opening 5 is provided on the upper surface side of the equipment base 2. Inside the opening 5, a wafer holding mechanism 30 including a chuck table 20 is disposed.

[0016] As shown in FIG. 2, the wafer holding mechanism 30 includes a chuck table 20 that holds the wafer 100 by means of a holding surface 22, a chuck table base 25 that supports the chuck table 20, a rotation mechanism 26 that rotates the chuck table 20 and the chuck table base 25, and a plurality of support pillars 28 that support the chuck table base 25.

[0017] The chuck table 20 has a substantially disk-shaped base (frame) 23, and a holding portion 21 made of a porous material such as porous ceramics is provided in a recess provided in the upper part of the base 23. The upper surface of the holding portion 21 serves as a holding surface 22 that suction-holds the wafer 100. In the chuck table 20, the holding portion 21 is connected to a suction source (not shown), so that the wafer 100 can be suction-held by the holding surface 22. In addition, a base surface 24, which is the upper surface of the base 23, has the same height as the holding surface 22 and is formed to be flush with the holding surface 22.

[0018] In this way, the chuck table 20 has a base 23 in addition to the holding surface 22 that holds the wafer 100. A base surface 24, which is the upper surface of the base 23, has a height related to the holding surface 22 (in this embodiment, the same height as the holding surface 22).

[0019] As shown in Fig. 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. And, as shown in Fig. 2, a horizontal movement mechanism 40 is provided below the wafer holding mechanism 30.

[0020] The horizontal movement mechanism 40 moves the chuck table 20 and the grinding mechanism 70 relative to each other in the Y-axis direction, which is a direction parallel to the holding surface 22. In this embodiment, the horizontal movement mechanism 40 is configured to move the wafer holding mechanism 30 including the chuck table 20 in the Y-axis direction relative to the grinding mechanism 70.

[0021] The horizontal movement mechanism 40 includes a pair of Y-axis guide rails 42 parallel to the Y-axis direction, a Y-axis movement table 45 that slides on these Y-axis guide rails 42, a Y-axis ball screw 43 parallel to the Y-axis guide rails 42, a Y-axis motor 44 connected to the Y-axis ball screw 43, a Y-axis encoder 46 for detecting the amount of rotation of the Y-axis ball screw 43, and a holding base 41 that holds these.

[0022] Y-axis moving table 45 is slidably installed on Y-axis guide rail 42 via slide member 451. A nut portion 401 is provided on the underside of Y-axis moving table 45. Y-axis ball screw 43 is threadedly engaged with nut portion 401. Y-axis motor 44 is connected to one end of Y-axis ball screw 43.

[0023] In the horizontal movement mechanism 40, the Y-axis motor 44 rotates the Y-axis ball screw 43, thereby moving the Y-axis movement table 45 in the Y-axis direction along the Y-axis guide rail 42. The wafer holding mechanism 30 is installed on the Y-axis movement table 45. Therefore, as the Y-axis movement table 45 moves in the Y-axis direction, the wafer holding mechanism 30 including the chuck table 20 moves in the Y-axis direction.

[0024] In this embodiment, the chuck table 20 is moved along the Y-axis direction by a horizontal movement mechanism 40 between a wafer placement area on the -Y direction side for placing the wafer 100 on the holding surface 22 and a grinding area on the +Y direction side where the wafer 100 is ground.

[0025] Furthermore, the Y-axis encoder 46 of the horizontal movement mechanism 40 is rotated by the Y-axis motor 44 rotating the Y-axis ball screw 43, and is able to recognize the amount of rotation (number of rotations and rotation angle) of the Y-axis ball screw 43. In this embodiment, the control unit 7 can detect the position of the chuck table 20 in the Y-axis direction based on the amount of rotation of the Y-axis ball screw 43 recognized by the Y-axis encoder 46.

[0026] 1, a column 3 is erected on the +Y direction side of the apparatus base 2. A grinding mechanism 70 for grinding the wafer 100 and an elevating mechanism 50 are provided in front of the column 3.

[0027] The lifting mechanism 50 moves the chuck table 20 and the grinding mechanism 70 relative to each other in the Z-axis direction (grinding feed direction), which is a direction perpendicular to the holding surface 22. In this embodiment, the lifting mechanism 50 is configured to move the grinding mechanism 70 up and down in the Z-axis direction relative to the wafer holding mechanism 30 including the chuck table 20.

[0028] The lifting mechanism 50 includes a pair of Z-axis guide rails 51 parallel to the Z-axis direction, a Z-axis moving table 53 that slides on the Z-axis guide rails 51, a Z-axis ball screw 52 parallel to the Z-axis guide rails 51, a Z-axis motor 54, a Z-axis encoder 55 for detecting the amount of rotation of the Z-axis ball screw 52, ​​and a holder 56 attached to the Z-axis moving table 53. The holder 56 holds a grinding mechanism 70.

[0029] Z-axis moving table 53 is slidably installed on Z-axis guide rail 51 via slide member 531 (see FIG. 2). Z-axis moving table 53 is provided with nut portion 501 (see FIG. 2). Z-axis ball screw 52 is threadedly engaged with nut portion 501. Z-axis motor 54 is connected to one end of Z-axis ball screw 52.

[0030] In the lifting mechanism 50, the Z-axis motor 54 rotates the Z-axis ball screw 52, ​​causing the Z-axis moving table 53 to move in the Z-axis direction along the Z-axis guide rail 51. As a result, the holder 56 attached to the Z-axis moving table 53 and the grinding mechanism 70 held by the holder 56 move in the Z-axis direction together with the Z-axis moving table 53.

[0031] Furthermore, Z-axis encoder 55 of lifting mechanism 50 is rotated by Z-axis motor 54 rotating Z-axis ball screw 52, ​​and is able to recognize the amount of rotation (number of rotations and rotation angle) of Z-axis ball screw 52. In this embodiment, control unit 7 is able to detect the height (height position) of grinding mechanism 70, which is moved in the Z-axis direction, based on the amount of rotation of Z-axis ball screw 52 recognized by Z-axis encoder 55. The height position of grinding mechanism 70 is, for example, the height position of the lower surface of grinding wheel 77.

[0032] The grinding mechanism 70 grinds the wafer 100 held by suction on the holding surface 22 with the underside of a grinding wheel 77. The grinding mechanism 70 includes a spindle housing 71 fixed to the holder 56, a spindle 72 rotatably held in the spindle housing 71, a spindle motor 73 that rotates the spindle 72, a wheel mount 74 attached to the lower end of the spindle 72, and a grinding wheel 75 supported by the wheel mount 74.

[0033] The spindle housing 71 is held by the holder 56 so as to extend in the Z-axis direction. The spindle 72 extends in the Z-axis direction so as to be perpendicular to the holding surface 22 of the chuck table 20, and is rotatably supported by the spindle housing 71.

[0034] The spindle motor 73 is connected to the upper end side of the spindle 72. The spindle motor 73 rotates the spindle 72 about a rotation axis extending in the Z-axis direction.

[0035] The wheel mount 74 is formed in a disk shape and is fixed to the lower end (tip) of the spindle 72. The wheel mount 74 supports the grinding wheel 75.

[0036] The grinding wheel 75 is formed to have an outer diameter that is approximately the same as the outer diameter of the wheel mount 74. The grinding wheel 75 includes a wheel base 76 formed from a metal material. A plurality of grinding stones 77 arranged in a ring shape are fixed to the underside of the wheel base 76 around the entire circumference. The grinding stones 77 are rotated together with the spindle 72 by the spindle motor 73, and grind the back surface 102 of the wafer 100 held on the chuck table 20 with their grinding surface (lower surface).

[0037] 2, a processing water channel 761 for supplying grinding water from a grinding water source 701 to the grinding wheel 77 is formed inside the spindle 72, the wheel mount 74, and the wheel base 76. When the wafer 100 is being ground, this grinding water is supplied between the lower surface of the grinding wheel 77 and the back surface 102 of the wafer 100, which is the surface to be ground.

[0038] 1, a measurement mechanism 60 is disposed on the side of the opening 5 in the apparatus base 2. The measurement mechanism 60 can measure the height of the holding surface 22 and the height of the wafer 100 in a contact manner.

[0039] That is, the measurement mechanism 60 brings a holding surface height measuring device 61 and a wafer height measuring device 62, which are measuring elements, into contact with the base surface 24 of the chuck table 20 and the wafer 100, respectively.

[0040] This allows the measurement mechanism 60 to measure the height of the holding surface 22 of the chuck table 20, which is flush with the base surface 24, and the height of the wafer 100. Furthermore, the measurement mechanism 60 can also calculate the thickness of the wafer 100 based on the difference between the measured height of the holding surface 22 and the height of the wafer 100.

[0041] The holding surface height measuring device 61 and the wafer height measuring device 62 may be non-contact distance measuring devices that use light or sound waves reflected by the base surface 24 and the upper surface of the wafer 100, respectively.

[0042] The grinding device 1 also includes a setup unit 80 below the grinding mechanism 70. The setup unit 80 is disposed between the base surface 24 of the chuck table 20 and the lower surface of the grinding wheel 77, and is used to detect the height position of the grinding mechanism 70 when the lower surface of the grinding wheel 77 comes into contact with the holding surface 22.

[0043] The control unit 7 of the grinding apparatus 1 includes a CPU that performs calculations according to a control program, and a storage medium such as a memory. The control unit 7 controls the above-mentioned components of the grinding apparatus 1 to perform grinding on the wafer 100. Prior to grinding the wafer 100, the control unit 7 uses the setup unit 80 to set up the grinding mechanism 70 (contact-type auto-setup).

[0044] Here, the configuration of the setup unit 80 will be described. As shown in Figures 1 and 2, the setup unit 80 includes a sensor unit 90 that is placed (interposed) between the base surface 24 of the base 23 of the chuck table 20 and the underside of the grinding wheel 77 of the grinding mechanism 70 during setup, an arm 82 that supports the sensor unit 90, a support column 83 that supports the arm 82, and a rotation motor 84.

[0045] The swivel motor 84 is disposed within the device base 2. Specifically, as shown in Fig. 2, a column 411 is provided on the upper surface of the holder 41 of the horizontal movement mechanism 40, and a motor support part 412 is provided on the side of the column 411. The swivel motor 84 is supported by this motor support part 412 so as to be able to rotate the support column 83 about a swivel axis 201 that passes through the support column 83 and extends in the Z-axis direction.

[0046] The support pillar 83 is supported by the motor support part 412 so as to extend upward from the rotation motor 84 along the Z-axis direction. The upper end of the support pillar 83 is disposed above the upper surface of the device base 2. The arm 82 is attached to the upper end of the support pillar 83 and extends horizontally above the device base 2 (see FIG. 1). The sensor unit 90 is attached to the tip of the arm 82.

[0047] In the setup unit 80, a swing motor 84 rotates a support column 83 around a swing shaft 201 extending in the Z-axis direction, thereby swinging and moving the arm 82 and the sensor unit 90 disposed at the tip of the arm 82 in the horizontal direction. This allows the sensor unit 90 to move in the horizontal direction within a range from above the base 23 of the chuck table 20 to outside the chuck table 20.

[0048] In this way, the arm 82, the support column 83 and the rotation motor 84 function as a horizontal movement mechanism that moves the sensor unit 90, including the block 91 described later, horizontally within a range from the top of the base 23 to outside the chuck table 20.

[0049] 2 and 3, arm 82 has a pair of upper and lower leaf springs 821 extending horizontally at its tip, and sensor unit 90 is attached to the tip of leaf spring 821. Leaf spring 821 is configured to be able to bend and elastically deform in the vertical direction. Therefore, sensor unit 90 can move up and down in the vertical direction relative to arm 82 in response to an external force.

[0050] In this way, the arm 82 having the leaf spring 821 functions as an elevation support portion that supports the sensor unit 90 including the block 91 so that it can be raised and lowered.

[0051] The sensor unit 90 is a part that is sandwiched between the lower surface of the grinding wheel 77 of the grinding mechanism 70 that has been lowered by the lifting mechanism 50 and the base surface 24 of the chuck table 20 during the setup operation.

[0052] As shown in FIG. 3, the sensor unit 90 includes a block 91 supported by a pair of leaf springs 821 on an arm 82, a table 93 attached to the top of the block 91, and an abutment portion 95 attached to the bottom of the block 91. The mechanism for supporting the sensor unit 90 is not limited to the leaf spring 821. Any mechanism may be used as long as it supports the sensor unit 90 in a manner that allows it to be raised and lowered so that it can be pressed down by the grinding wheel 77 lowered by the lifting mechanism 50.

[0053] The upper surface of the table 93 comes into contact with the lower surface of the grinding wheel 77, which is lowered by the lifting mechanism 50. The table 93 is attached to the upper surface of the block 91. The table 93 has a through-hole 933 in its center that passes through the upper and lower surfaces. The setup unit 80 also includes a cleaning water nozzle 92 that is disposed beside the table 93 and that supplies cleaning water to the upper surface of the table 93. The cleaning water nozzle 92 may be attached to the arm 82 so as to pivot together with the sensor unit 90, for example.

[0054] The table 93 has a substantially rectangular parallelepiped shape, and has a concave spherical surface 931 as a first spherical surface on its lower surface. Furthermore, a convex spherical surface 912 is provided on the upper surface of block 91. This convex spherical surface 912 has a size corresponding to the concave spherical surface 931 of table 93, and can be fitted into concave spherical surface 931. Furthermore, a coil spring 913 is attached to block 91, connecting the upper surface of block 91 to the lower surface of table 93 (outside of concave spherical surface 931). Coil spring 913 has a diameter larger than the diameters of concave spherical surface 931 and convex spherical surface 912, and extends to cover the periphery of convex spherical surface 912.

[0055] The coil spring 913 is an example of a levitation means. That is, the coil spring 913 is configured to levitate the table 93 upward when the table 93 is not pressed down by the grinding wheel 77, thereby keeping the concave spherical surface 931 of the table 93 and the convex spherical surface 912 of the block 91 apart from each other.

[0056] In addition, the coil spring 913 contracts when the table 93 is pressed down by the grinding wheel 77, allowing the concave spherical surface 931 of the table 93 and the convex spherical surface 912 of the block 91 to come into contact with each other (allowing the convex spherical surface 912 to support the concave spherical surface 931).

[0057] That is, when the table 93 is pressed down by the grinding wheel 77, it descends relative to the block 91 against the biasing force of the coil spring 913. As a result, the convex spherical surface 912 of the block 91 fits into the concave spherical surface 931 of the table 93, and this convex spherical surface 912 supports the concave spherical surface 931. That is, the convex spherical surface 912 can fit into the concave spherical surface 931 as the first spherical surface, and functions as a second spherical surface that supports the concave spherical surface 931 of the table 93 that is pressed down by the grinding wheel 77 of the grinding mechanism 70 that is lowered by the elevating mechanism 50.

[0058] In this way, the block 91 can support the table 93 so that it can move up and down freely by means of the coil spring 913. That is, the block 91 functions as a table support portion that supports the table 93 so that it can move up and down freely.

[0059] Note that concave spherical surface 931 as the first spherical surface and convex spherical surface 912 as the second spherical surface are, for example, surfaces (spherical crowns) that correspond to parts of the side surfaces of a perfect sphere (perfect spherical surfaces).

[0060] The contact portion 95 is disposed below the table 93 of the block 91 and is a portion that comes into contact with the base surface 24 of the base 23 of the chuck table 20. The contact portion 95 has a plate-shaped base 951 and a cylindrical portion 952 attached to the base 951.

[0061] The base 951 of the abutment portion 95 is disposed in an internal chamber 915 provided inside the block 91. The internal chamber 915 is sized to allow the abutment portion 95, including the base 951, to move up and down within the internal chamber 915. A through-hole 916 is formed in the lower surface of the internal chamber 915, penetrating the lower surface of the block 91 and extending to the outside. The cylindrical portion 952 of the abutment portion 95 is inserted into the through-hole 916 and is disposed so as to extend below the block 91 via the through-hole 916. Note that the through-hole 916 has a diameter smaller than the base 951 of the abutment portion 95 and larger than the cylindrical portion 952. Therefore, the entire abutment portion 95, including the base 951, will not fall through the through-hole 916 and below the block 91.

[0062] The contact portion 95 having such a configuration can move up and down in the Z-axis direction within the inner chamber 915 of the block 91. Therefore, the block 91 is connected to the table support portion and functions as a contact support portion that supports the contact portion 95 so that it can move up and down.

[0063] The sensor unit 90 also has a sensor 96 inside the block 91. This sensor 96 detects that the contact portion 95 has risen relative to the block 91 (for example, by a predetermined amount). In this embodiment, the sensor 96 is configured to detect the contact portion 95 rising relative to the block 91 inside the inner chamber 915, causing the base 951 to rise inside the inner chamber 915, and turn ON. The sensor 96 may be either a non-contact type or a contact type.

[0064] Next, the setup of the grinding mechanism 70 using the setup unit 80 controlled by the control unit 7 will be described.

[0065] In the setup according to this embodiment, first, as shown in Fig. 2, the control unit 7 uses the horizontal movement mechanism 40 to adjust the position of the chuck table 20 so that the base surface 24 of the chuck table 20 is located below the grinding wheel 77 of the grinding mechanism 70. Thereafter, the control unit 7 controls the turning motor 84 of the setup unit 80 to turn the arm 82 and the sensor unit 90, and as shown in Figs. 2 and 3, the sensor unit 90 is located between the lower surface of the grinding wheel 77 and the base surface 24 of the chuck table 20.

[0066] Furthermore, the control unit 7 supplies cleaning water from the cleaning water nozzle 92 to the upper surface of the table 93. Then, the control unit 7 lowers the grinding mechanism 70 using the lifting mechanism 50, and as shown in FIG. 4, the lower surface of the grinding wheel 77 comes into contact with the upper surface of the table 93 of the sensor unit 90. At this time, the cleaning water supplied from the cleaning water nozzle 92 to the upper surface of the table 93 flows down through the through-holes 933 formed in the table 93. At this time, the cleaning water cleans the upper surface of the table 93, the lower surface of the grinding wheel 77, the concave spherical surface 931, and the convex spherical surface 912 of the block 91.

[0067] Then, the control unit 7 controls the lifting mechanism 50 to further lower the grinding wheel 77. As a result, the table 93, whose upper and lower surfaces are now parallel to each other, is pushed downward by the grinding wheel 77 and moves downward relative to the block 91 against the biasing force of the coil spring 913. As a result, the concave spherical surface 931 of the table 93 is fitted into and supported by the convex spherical surface 912 of the block 91, and the table 93 and the block 91 become integrated.

[0068] Thereafter, the control unit 7 controls the lifting mechanism 50 to further lower the grinding wheel 77. As a result, as shown in Fig. 5, the pair of leaf springs 821 at the tip of the arm 82 bends, the sensor unit 90 lowers, and the lower end of the cylindrical portion 952 of the abutment portion 95 provided at the bottom of the block 91 comes into contact with the base surface 24 of the chuck table 20. As a result, the pedestal 951 of the abutment portion 95 is pushed upward within the inner chamber 915 of the block 91 and rises within the inner chamber 915, and the sensor 96 detects the pedestal 951 and turns ON.

[0069] When sensor 96 turns ON, control unit 7 stops the lowering of grinding mechanism 70 by lifting mechanism 50, and acquires the height position of grinding mechanism 70 at this time using Z-axis encoder 55 (see FIG. 2) of lifting mechanism 50. In addition, control unit 7 stops the supply of cleaning water from cleaning water nozzle 92.

[0070] The control unit 7 then subtracts the previously recognized length of the sensor unit 90 in the Z-axis direction (the distance from the upper surface of the table 93 in the sensor unit 90 to the lower end of the cylindrical portion 952 of the abutment portion 95 when the sensor 96 is turned ON) from the acquired height position of the grinding mechanism 70 to determine the origin height position of the grinding mechanism 70, and stores this origin height position. This origin height position of the grinding mechanism 70 is the height position of the grinding mechanism 70 when the lower surface of the grinding wheel 77 contacts the base surface 24 (i.e., the holding surface 22 that is flush with the base surface 24).

[0071] As shown in Fig. 6, the lower surface of the grinding wheel 77 may be tilted from the horizontal plane. In this embodiment, before the table 93 of the sensor unit 90 comes into contact with the grinding wheel 77, it is raised above the block 91 by the coil spring 913, and the concave spherical surface 931 and the convex spherical surface 912 are spaced apart. This allows the table 93 to easily tilt with respect to the block 91. Therefore, when the tilted lower surface of the grinding wheel 77 comes into contact with the upper surface of the table 93, the tilt of the table 93 is changed to follow the tilt of the grinding wheel 77, and the upper surface of the table 93 and the lower surface of the grinding wheel 77 become parallel to each other, as shown in Fig. 6.

[0072] In this state, the table 93 is pushed downward by the grinding wheel 77, and moves downward relative to the block 91 against the biasing force of the coil spring 913, and the concave spherical surface 931 comes into contact with and is supported by the convex spherical surface 912, and the tilted table 93 and block 91 become one unit.

[0073] 5, the control unit 7 causes the lifting mechanism 50 to further lower the grinding wheel 77 until the lower end of the cylindrical portion 952 of the contact portion 95 comes into contact with the base surface 24 of the chuck table 20 and the sensor 96 turns ON. Thereafter, the control unit 7 stops the lowering of the grinding mechanism 70, determines the origin height position of the grinding mechanism 70, and stores this origin height position.

[0074] The setup is completed through the above steps. After the setup, the control unit 7 performs grinding on the wafer 100. At this time, the control unit 7 determines the height position (grinding start height position) of the grinding mechanism 70 such that the lower surface of the grinding wheel 77 is positioned directly above the wafer 100 held on the holding surface 22 of the chuck table 20, based on the origin height position of the grinding mechanism 70 determined during the setup and the thickness of the wafer 100 before grinding that is stored in advance.

[0075] Then, the control unit 7 uses the lifting mechanism 50 to lower the grinding mechanism 70, position the grinding mechanism 70 at the grinding start height position, and start grinding the wafers 100. At this time, the control unit 7 uses the lifting mechanism 50 to lower the grinding mechanism 70 at a relatively high initial speed, and position the grinding mechanism 70 at the grinding start height position. Thereafter, the control unit 7 uses the lifting mechanism 50 to lower the grinding mechanism 70 at a relatively low grinding speed, and grinding of the wafers 100 is carried out.

[0076] As described above, in the sensor unit 90 of this embodiment, when the table 93 is not pressed down by the grinding wheel 77, the coil spring 913 of the block 91 keeps the concave spherical surface 931 of the table 93 and the convex spherical surface 912 of the block 91 apart from each other. This makes it possible to avoid the occurrence of contact friction between the concave spherical surface 931 and the convex spherical surface 912. Therefore, when the grinding wheel 77 is lowered and presses down the table 93 against the biasing force of the coil spring 913, the table 93 can easily tilt relative to the block 91 in accordance with the tilt of the grinding wheel 77.

[0077] Therefore, when the lower surface of the tilted grinding wheel 77 abuts against the upper surface of the table 93, the tilt of the table 93 is changed to match the tilt of the grinding wheel 77, so that the upper surface of the table 93 and the lower surface of the grinding wheel 77 become parallel to each other. Thereafter, as the grinding wheel 77 descends, the concave spherical surface 931 of the table 93 comes into contact with the convex spherical surface 912 of the block 91, and the tilted table 93 and the block 91 become one unit. In this state, the cylindrical portion 952 of the abutting portion 95 abuts against the base surface 24 of the chuck table 20, and the origin height position of the grinding mechanism 70 is determined.

[0078] In this way, in this embodiment, the inclination of the table 93 can be appropriately adjusted to follow the inclination of the grinding wheel 77. Therefore, in this embodiment, when determining the origin height position of the grinding mechanism 70, the lower surface of the grinding wheel 77 and the upper surface of the table 93 can be made favorably parallel, thereby reducing the error in the determined origin height position of the grinding mechanism 70. Therefore, for example, it is possible to prevent the air cutting time from becoming long when grinding the wafer 100.

[0079] Furthermore, in this embodiment, during setup, cleaning water is supplied from the cleaning water nozzle 92 toward the upper surface of the table 93 to clean the upper surface of the table 93, the lower surface of the grinding wheel 77, the concave spherical surface 931, and the convex spherical surface 912 of the block 91. This allows foreign matter such as machining chips adhering to these surfaces to be effectively cleaned (discharged). Therefore, it is possible to effectively prevent foreign matter such as machining chips from being caught between the table 93 and the block 91, for example, between the concave spherical surface 931 and the convex spherical surface 912.

[0080] In the sensor unit 90 of this embodiment, a coil spring 913 is used as levitation means for levitating the table 93 upward and keeping the concave spherical surface 931 of the table 93 and the convex spherical surface 912 of the block 91 apart from each other when the table 93 is not pressed down by the grinding wheel 77. In this regard, water may be used to keep the concave spherical surface 931 of the table 93 and the convex spherical surface 912 of the block 91 apart from each other.

[0081] 7, convex spherical surface 912 is provided at the bottom of recessed portion 911 provided in the upper portion of block 91. Furthermore, water channel 702 connected to water source 703 passes through the bottom of recessed portion 911 and convex spherical surface 912, and opens at the central apex of convex spherical surface 912. Therefore, water 87 from water source 703 is supplied into recessed portion 911 via the apex of convex spherical surface 912 and accumulates therein. Also, packing 917 made of, for example, a sponge or rubber plate is formed on the inner surface of recess 911. This packing 917 does not prevent table 93 from moving up and down within recess 911, while preventing water within recess 911 from leaking out between the side surface of recess 911 and the side surface of table 93. In this configuration, the table 93 does not have a through hole, but as shown in Figure 7, the above-mentioned cleaning water nozzle 92 is provided, and the upper surface of the table 93 and the lower surface of the grinding wheel 77 are cleaned with cleaning water supplied from the cleaning water nozzle 92.

[0082] In this configuration, when the table 93 is not pressed down by the grinding wheel 77, the table 93 floats in the recess 911 of the block 91 on the water 97 accumulated in the recess 911, as shown in Fig. 7. This causes the concave spherical surface 931 of the table 93 and the convex spherical surface 912 of the block 91 to be separated from each other.

[0083] During setup, the grinding mechanism 70 is lowered by the lifting mechanism 50, and as shown in FIG. 8 , when the lower surface of the grinding wheel 77 comes into contact with the upper surface of the table 93, the table 93 is pushed downward by the grinding wheel 77 and lowers relative to the block 91 against the buoyancy of the water 97. As a result, the concave spherical surface 931 of the table 93 is fitted into and supported by the convex spherical surface 912 of the block 91, and the table 93 and the block 91 become one unit. At this time, the water 97 in the recess 911 that has been displaced by the table 93 is discharged from the gap between the packing 917 and the table 93.

[0084] In this way, even in a configuration using water 97 instead of coil spring 913, when table 93 is not pressed down by grinding wheel 77, table 93 can be floated upward to keep the concave spherical surface 931 of table 93 and the convex spherical surface 912 of block 91 apart from each other, and when table 93 is pressed down by grinding wheel 77, the concave spherical surface 931 of table 93 and the convex spherical surface 912 of block 91 can be brought into contact with each other (the convex spherical surface 912 can support the concave spherical surface 931). That is, in this case, water source 703, water channel 702, and water 97 function as a floating means for floating table 93.

[0085] Therefore, in this case too, when the table 93 is not pressed down by the grinding wheel 77, the concave spherical surface 931 of the table 93 and the convex spherical surface 912 of the block 91 are separated from each other, thereby avoiding the occurrence of contact friction between the concave spherical surface 931 and the convex spherical surface 912, and allowing the table 93 to easily tilt relative to the block 91 in accordance with the tilt of the grinding mechanism 70.

[0086] Furthermore, with this configuration, during setup, water 97 in recess 911 passes between table 93 and block 91, including between concave spherical surface 931 and convex spherical surface 912, and is discharged to the outside of sensor unit 90 through the gap between packing 917 and table 93. This allows foreign matter such as machining debris between table 93 and block 91 to be effectively washed away (discharged). Therefore, it is possible to effectively prevent foreign matter such as machining debris from being trapped between table 93 and block 91, for example, between concave spherical surface 931 and convex spherical surface 912.

[0087] 3, a concave spherical surface 931 serving as a first spherical surface is provided on the lower surface of the table 93, and a convex spherical surface 912 serving as a second spherical surface supporting the first spherical surface is provided on the upper surface of the block 91. In this regard, as shown in FIG. 9, a convex spherical surface 932 serving as a first spherical surface may be provided on the lower surface of the table 93, and a concave spherical surface 918 serving as a second spherical surface may be provided on the upper surface of the block 91. This concave spherical surface 918 can be fitted into the convex spherical surface 932 serving as the first spherical surface, and supports the convex spherical surface 932 of the table 93 pressed down by the grinding wheel 77 lowered by the lifting mechanism 50.

[0088] The convex spherical surface 932 of the table 93 has a size corresponding to the concave spherical surface 918 of the block 91, and can be fitted onto the concave spherical surface 918. Furthermore, even in this configuration, the above-mentioned coil spring 913, which connects the bottom surface of the recess 911 and the lower surface of the table 93, is attached around the concave spherical surface 918 on the bottom surface of the recess 911 of the block 91 so as to cover the periphery of the convex spherical surface 932.

[0089] Even in this configuration, when the table 93 is not pressed down by the grinding wheel 77, the table 93 is levitated upward by the coil spring 913. Therefore, the convex spherical surface 932 of the table 93 and the concave spherical surface 918 of the block 91 are separated from each other. Furthermore, when the table 93 is pressed down by the grinding wheel 77, the coil spring 913 contracts, causing the convex spherical surface 932 of the table 93 and the concave spherical surface 918 of the block 91 to come into contact with each other, and the convex spherical surface 932 is supported by the concave spherical surface 918.

[0090] Therefore, even in this configuration, when the table 93 is not pressed down by the grinding wheel 77, the convex spherical surface 932 of the table 93 and the concave spherical surface 918 of the block 91 are separated from each other, thereby avoiding the occurrence of contact friction between the convex spherical surface 932 and the concave spherical surface 918, and allowing the table 93 to easily tilt relative to the block 91 in accordance with the tilt of the grinding mechanism 70.

[0091] In addition, in this configuration, similar to the configuration shown in Figure 3, a cleaning water nozzle 92 for supplying cleaning water to the upper surface of the table 93 is arranged next to the table 93, and the table 93 has a through hole 933 that penetrates from the top to the bottom. In this configuration, a plurality of (for example, two) communication holes 934 extending obliquely downward are provided inside the convex spherical surface 932 of the table 93, connecting the through-hole 933 with the surface of the convex spherical surface 932. Furthermore, the block 91 is provided with a drainage channel 919 that connects an opening provided at the bottom in the center of the concave spherical surface 918 of the block 91 with the side surface of the block 91.

[0092] In this configuration, when the grinding wheel 77 is brought into contact with the table 93 during setup, cleaning water is supplied from the cleaning water nozzle 92 to the upper surface of the table 93. This causes the cleaning water to flow down the through-hole 933 of the table 93, pass through the communication hole 934 in the convex spherical surface 932, and spray out obliquely downward from the convex spherical surface 932, and then pass through the concave spherical surface 918 and the drainage channel 919 of the block 91 to be discharged to the outside of the block 91. This makes it possible to effectively clean (discharge) foreign matter such as machining chips adhering to the upper surface of the table 93, the lower surface of the grinding wheel 77, the convex spherical surface 932, and the concave spherical surface 918 of the block 91. Therefore, it is possible to effectively prevent foreign matter such as machining chips from being caught between the table 93 and the block 91, for example, between the concave spherical surface 931 and the convex spherical surface 912.

[0093] Also in this configuration, in order to keep the convex spherical surface 932 of the table 93 and the concave spherical surface 918 of the block 91 apart from each other, water 97 may be used instead of the coil spring 913 as shown in FIG.

[0094] In addition, even in a configuration in which the levitation means uses a coil spring 913 to levitate the table 93, water 97 may be supplied to prevent the intrusion of foreign matter such as machining chips when the concave spherical surface 931 and the convex spherical surface 912 come into contact.

[0095] Furthermore, in this embodiment, the base surface 24, which is the upper surface of the base 23, is configured to be at the same height as the holding surface 22. In this regard, it is sufficient that the base surface 24 has a height related to the holding surface 22. For example, it is sufficient that the difference in height between the base surface 24 and the holding surface 22 is clear. Even with this configuration, it is possible to determine the origin height position of the grinding mechanism 70 based on the height position of the grinding mechanism 70 when the sensor 96 is turned ON, the length of the sensor unit 90 in the Z-axis direction at this time, and the difference in height between the base surface 24 and the holding surface 22.

[0096] In this embodiment, the block 91 serves both as a table support portion that supports the table 93 and as a contact support portion that supports the contact portion 95. In this regard, the table support portion and the contact support portion may be separate members. In this case, the contact support portion is connected to the lower portion of the table support portion, and the table support portion and the contact support portion are configured to be able to move downward integrally toward the base surface 24 when the grinding wheel 77 presses the table 93 downward. [Explanation of symbols]

[0097] 1: grinding device, 2: device base, 3: column, 5: opening, 7: control unit, 12: bellows cover, 20: chuck table, 21: holding portion, 22: holding surface, 23: base, 24: base surface, 25: chuck table base, 26: rotation mechanism, 28: Support column, 30: Wafer holding mechanism, 39: Cover plate, 40: horizontal movement mechanism, 41: support table, 42: Y-axis guide rail, 43: Y-axis ball screw, 44: Y-axis motor, 45: Y-axis moving table, 46: Y-axis encoder, 50: Elevating mechanism, 51: Z-axis guide rail, 52: Z-axis ball screw, 53: Z-axis moving table, 54: Z-axis motor, 55: Z-axis encoder, 56: holder, 60: Measuring mechanism, 61: Holding surface height measuring device, 62: Wafer height measuring device, 70: grinding mechanism, 71: spindle housing, 72: spindle, 73: spindle motor, 74: wheel mount, 75: grinding wheel, 76: Wheel base, 77: Grinding wheel, 80: Setup unit, 82: Arm, 83: Support column, 84: Swivel motor, 90: Sensor unit, 91: Block, 92: cleaning water nozzle, 93: table, 95: contact part, 96: sensor, 97: water, 100: wafer, 101: front surface, 102: back surface, 103: protective tape, 201: rotating shaft, 401: nut portion, 411: column, 412: motor support portion, 451: slide member, 501: nut portion, 531: slide member, 701: grinding water source, 702: Waterway, 703: Water source, 761: Processed waterway, 821: Leaf spring, 911: Recess, 912: convex spherical surface, 913: coil spring, 915: inner chamber, 916: through hole, 917: Packing, 918: Concave spherical surface, 919: Drainage channel, 931: Concave spherical surface, 932: Convex spherical surface, 933: Through hole, 934: Communication hole, 951: Base, 952: Cylindrical portion

Claims

[Claim 1] A grinding apparatus comprising: a chuck table having a base outside a holding surface for holding a wafer, the upper surface of which is at a height related to the holding surface; a grinding mechanism for grinding the wafer with a lower surface of a grinding wheel; a lifting mechanism for raising and lowering the grinding mechanism; and a setup unit disposed between the upper surface of the base and the lower surface of the grinding wheel for detecting the height position of the grinding mechanism when the lower surface of the grinding wheel comes into contact with the holding surface, The setup unit comprises: A table and a table support section that supports the table so that it can be raised and lowered; a contact portion disposed below the table and in contact with the upper surface of the base; a contact support part connected to the table support part and supporting the contact part so as to be able to move up and down; a sensor that detects that the corresponding contact portion has risen relative to the corresponding contact support portion; a lifting support section that supports the table support section and the corresponding contact support section so that they can be raised and lowered; a horizontal movement mechanism that moves the table support portion and the corresponding contact support portion in a horizontal direction within a range from above the base to outside the chuck table, the table has a first spherical surface on its lower surface; The table support includes: a second spherical surface supporting the first spherical surface of the table pressed down by the grinding wheel of the grinding mechanism which is lowered by the lifting mechanism; and a floating means for keeping the first spherical surface and the second spherical surface of the table apart from each other when the table is not pressed down by the grinding wheel. Grinding equipment.

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