Grinding device

Abstract

The present application provides a grinding device which appropriately crosses grinding marks of three or more grinding mechanisms. In the grinding device, a first grinding mechanism and a second grinding mechanism are arranged with respect to a chuck table in a manner that a second grinding mark of a wafer generated by grinding with a second grinding tool crosses a first grinding mark of the wafer generated by grinding with a first grinding tool, and the second grinding mechanism and a third grinding mechanism are arranged with respect to the chuck table in a manner that a third grinding mark of the wafer generated by grinding with a third grinding tool crosses the second grinding mark of the wafer generated by grinding with the second grinding tool.

Description

Technical Field

[0001] This invention relates to grinding apparatus. Background Technology

[0002] For example, Patent Document 1 discloses a grinding apparatus for grinding a wafer held on a chuck table using a grinding wheel. This grinding apparatus includes a first grinding mechanism and a second grinding mechanism. In this apparatus, the grinding marks generated by the grinding of the first grinding wheel mounted on the first grinding mechanism intersect with the grinding marks generated by the grinding of the second grinding wheel mounted on the second grinding mechanism.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2000-288881

[0004] However, when using more than three grinding mechanisms, it is difficult to make the grinding marks formed on the wafer by the grinding mechanism that grinds the wafer first intersect with the grinding marks formed on the wafer by the grinding mechanism that grinds the wafer later. Summary of the Invention

[0005] Therefore, the object of the present invention is to make the grinding marks of three or more grinding mechanisms in a grinding apparatus appropriately intersect.

[0006] According to one aspect of the invention, a grinding apparatus is provided for grinding a wafer, wherein the grinding apparatus comprises: at least four chuck stages holding the wafer via a holding surface; a first grinding mechanism grinding the wafer by contacting the lower surfaces of a first grinding tool arranged in a ring with a radial region of the wafer held by the holding surface; a second grinding mechanism grinding the wafer by contacting the lower surfaces of a second grinding tool arranged in a ring with a radial region of the wafer held by the holding surface; a third grinding mechanism grinding the wafer by contacting the lower surfaces of a third grinding tool arranged in a ring with a radial region of the wafer held by the holding surface; a first grinding feed mechanism feeding the first grinding tool in a grinding feed direction perpendicular to the holding surface; and a second grinding feed mechanism feeding the second grinding tool in a grinding feed direction perpendicular to the holding surface. The grinding feed is performed in a grinding feed direction perpendicular to the holding surface; a third grinding feed mechanism performs grinding feed in a grinding feed direction perpendicular to the holding surface; and a rotary table on which the chuck table is disposed. By rotating the rotary table about the center axis, the chuck table can be positioned relative to the first grinding wheel, the second grinding wheel, and the third grinding wheel respectively. The first grinding mechanism and the second grinding mechanism are disposed relative to the chuck table in such a way that the second grinding mark of the wafer produced by the grinding of the second grinding wheel intersects with the first grinding mark of the wafer produced by the grinding of the first grinding wheel. The second grinding mechanism and the third grinding mechanism are disposed relative to the chuck table in such a way that the third grinding mark of the wafer produced by the grinding of the third grinding wheel intersects with the second grinding mark of the wafer produced by the grinding of the second grinding wheel.

[0007] In one aspect of the grinding apparatus of the present invention, a first grinding mechanism, a second grinding mechanism, and a third grinding mechanism are arranged relative to a chuck table such that a second grinding mark on the wafer intersects with a first grinding mark on the wafer, and a third grinding mark on the wafer intersects with a second grinding mark on the wafer. Thus, the wafer is ground by the second grinding tool by scraping away the first grinding mark. Furthermore, the wafer is ground by the third grinding tool by scraping away the second grinding mark. Therefore, a high-quality wafer with small thickness deviation and high bending strength can be obtained.

[0008] In addition, due to the appropriate impact force applied to the second and third grinding wheels during grinding, a spontaneous sharpening effect is generated to maintain the grinding force. Attached Figure Description

[0009] Figure 1 This is a top view showing the structure of the grinding device.

[0010] Figure 2 It is a perspective view showing the structure of the rotary table, chuck table, grinding mechanism, and grinding feed mechanism.

[0011] Figure 3 It is a top view showing the grinding area formed by grinding an abrasive tool.

[0012] Figure 4 This is a top view showing the structure of a grinding device with five chuck worktables arranged on a rotary table and four grinding mechanisms.

[0013] Figure 5 This is a top view showing the structure of a grinding device with five chuck worktables arranged on a rotary table and four grinding mechanisms.

[0014] Label Explanation

[0015] 1: Grinding device; 5: Wafer; 7: Control unit; 400: Loading / unloading area; 10: First grinding mechanism; 11: First grinding wheel; 401: First grinding area; 431: First grinding area; 451: First grinding mark; 20: Second grinding mechanism; 21: Second grinding wheel; 402: Second grinding area; 432: Second grinding area; 452: Second grinding mark 30: Third grinding mechanism; 31: Third grinding wheel; 403: Third grinding area; 433: Third grinding area; 453: Third grinding mark; 35: Fourth grinding mechanism; 36: Fourth grinding wheel; 434: Fourth grinding area; 454: Fourth grinding mark; 40: Spindle housing; 41: Spindle unit; 42: Spindle; 43: Grinding wheel; 44: Spindle motor; 50: Chuck worktable; 52: Holding surface; 60: Turntable; 61: Water tank; 300: Worktable base; 301: Outer side; 302: Inner side; 303: Side wall; 320: Support column; 310: Support pad; 70: First grinding feed mechanism; 80: Second grinding feed mechanism; 90: Third grinding feed mechanism; 95: Fourth grinding feed mechanism; 101: Column; 104: Guide rail; 110: Support; 114: Z-axis motor; 115: Ball screw; 116: Lifting platform; 150: First box; 151: Second box; 153: Robot; 156: Temporary worktable; 154: Loading mechanism; 157: Unloading mechanism; 201: First device base; 202: Second device base; 240: Thickness sensor; 265: Rotary cleaning unit. Detailed Implementation

[0016] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1The grinding apparatus 1 shown has a first apparatus base 201 and a second apparatus base 202 disposed on the -Y direction side of the first apparatus base 201. The wafer 5 is loaded and unloaded on the first apparatus base 201. The wafer 5 is processed on the second apparatus base 202.

[0017] That is, the grinding apparatus 1 has a control unit 7, and a first grinding mechanism 10, a second grinding mechanism 20, and a third grinding mechanism 30 are provided on the second apparatus base 202. Under the control of the control unit 7, the first grinding mechanism 10, the second grinding mechanism 20, and the third grinding mechanism 30 are used to grind the wafer 5 held by the chuck table 50.

[0018] In the grinding apparatus 1, a first housing 150 and a second housing 151 are arranged on the front side (+Y direction side) of the first apparatus base 201. The first housing 150 and the second housing 151 hold wafers 5 before or after processing. Hereinafter, the first housing 150 holds the wafers 5 before processing, while the second housing 151 holds the wafers 5 after processing.

[0019] The openings (not shown) of the first box 150 and the second box 151 face the -Y direction. A robot 153 is arranged on the -Y direction side of these openings. The robot 153 moves the processed wafer 5 into the second box 151. In addition, the robot 153 removes the unprocessed wafer 5 from the first box 150 and places it on the temporary placement table 156 for temporarily placing the wafer 5.

[0020] A loading mechanism 154 is provided on the -X direction side of the second device base 202. The loading mechanism 154 has a loading pad 155 for holding the wafer 5. The loading mechanism 154 holds the wafer 5 placed on the temporary stage 156 through the loading pad 155 and loads the wafer 5 to the chuck stage 50.

[0021] The chuck stage 50 has a holding surface 52 for holding the wafer 5. The holding surface 52 is a cone-shaped surface with its center as the vertex, which is connected to an attraction source (not shown) and is capable of attracting and holding the wafer 5.

[0022] The chuck stage 50 holds the wafer 5 transported by the loading mechanism 154 via the holding surface 52. Furthermore, the chuck stage 50 rotates about a rotation axis that passes through the center of the holding surface 52 and extends in the Z-axis direction, thereby enabling the holding surface 52 holding the wafer 5 to rotate.

[0023] In this embodiment, four chuck worktables 50 are arranged at equal intervals in the circumferential direction on the upper surface of the turntable 60 disposed on the second device base 202. The turntable 60 is disposed on the second device base 202 in such a way that it can rotate about its center axis. That is, the turntable 60 can rotate about an axis extending in the Z-axis direction from the center of the turntable 60 and driven by the turntable motor (not shown). As the turntable 60 rotates, the four chuck worktables 50 revolve around it. Thus, the chuck worktables 50 can be sequentially positioned in the loading / unloading area 400 near the loading mechanism 154 and the unloading mechanism 157, in the first grinding area 401 below the first grinding mechanism 10, in the second grinding area 402 below the second grinding mechanism 20, and in the third grinding area 403 below the third grinding mechanism 30.

[0024] The loading / unloading area 400 is the area (position) of the chuck table 50 where the loading mechanism 154 loads the wafer 5 and the unloading mechanism 157 removes the wafer 5. The loading mechanism 154 transports the wafer 5 to the chuck table 50 in the loading / unloading area 400.

[0025] The first to third grinding areas are the areas where the chuck stage 50 is positioned so that the wafer 5 can be ground by the first grinding mechanism 10, the second grinding mechanism 20 and the third grinding mechanism 30, respectively.

[0026] The first grinding zone 401 is located on the +Y direction side of the second device base 202. A first grinding mechanism 10 and a first grinding feed mechanism 70 are provided in the first grinding zone 401 to perform grinding feed in the grinding feed direction. The grinding feed direction is perpendicular to the holding surface 52 of the chuck table 50.

[0027] The first grinding mechanism 10 grinds the wafer 5 through the lower surface of the annular first grinding tool 11. That is, the first grinding mechanism 10 makes the lower surface of the first grinding tool 11 contact the radial region of the wafer 5 held on the conical holding surface 52, thereby grinding the wafer 5.

[0028] In addition, a thickness sensor 240 for measuring the thickness of the wafer 5 being ground is provided near the first grinding mechanism 10.

[0029] Furthermore, a second grinding region 402 and a third grinding region 403 are provided on the -Y direction side of the second device base 202. A second grinding mechanism 20 and a second grinding feed mechanism 80 for feeding the second grinding mechanism 20 in the grinding feed direction are provided in the second grinding region 402. A third grinding mechanism 30 and a third grinding feed mechanism 90 for feeding the third grinding mechanism 30 in the grinding feed direction are provided in the third grinding region 403.

[0030] The second grinding mechanism 20 grinds the wafer 5 using the lower surface of the annular second grinding tool 21. Furthermore, the third grinding mechanism 30 grinds the wafer 5 using the lower surface of the annular third grinding tool 31.

[0031] That is, the second grinding mechanism 20 (the third grinding mechanism 30) makes the lower surface of the second grinding tool 21 (the third grinding tool 31) contact the radius region of the wafer 5 held on the holding surface 52, thereby grinding the wafer 5.

[0032] Furthermore, thickness sensors 240 for measuring the thickness of the ground wafer 5 are respectively provided near the second grinding mechanism 20 and the third grinding mechanism 30.

[0033] In addition, in this embodiment, the loading and unloading area 400 is provided with a two-fluid cleaning device for cleaning the holding surface 52 using two-fluid cleaning water that is a mixture of water and air, and a holding surface abrasive cleaning device for cleaning the holding surface 52 using an abrasive (both not shown).

[0034] In this embodiment, a chuck worktable 50 is sequentially positioned on the first grinding wheel 11, the second grinding wheel 21 and the third grinding wheel 31 by rotating the turntable 60, and the wafer 5 held on the holding surface 52 is subjected to in-cut grinding using these grinding wheels.

[0035] In addition, in this embodiment, for example, the first grinding wheel 11 is a rough grinding wheel containing relatively large abrasive grains, the second grinding wheel 21 is a grinding wheel containing abrasive grains of medium size, and the third grinding wheel 31 is a fine grinding wheel containing relatively small abrasive grains.

[0036] The ground wafer 5 is taken out of the chuck table 50 in the transfer area 400 by the transfer mechanism 157 and transported to the rotary cleaning unit 265 which is arranged adjacent to the turntable 60.

[0037] In the rotary cleaning unit 265, pure water is supplied to the wafer 5, causing the wafer 5 to rotate about its central axis. This cleans the wafer 5. Then, the wafer 5 is dried by rotating it at a higher speed than during cleaning.

[0038] Alternatively, the chip 5 can be cleaned by providing a cleaning solution before using pure water, and then the solution can be removed using pure water.

[0039] After being rotated and cleaned by the rotating cleaning unit 265, the wafer 5 was moved into the second box 151 by the robot 153.

[0040] Here, the structures near the rotary table 60, the chuck table 50, the grinding mechanism, and the grinding feed mechanism will be described in more detail.

[0041] Turntable 60 is separated from support pad 310 (see reference) Figure 3 It is set on the workbench base 300. For example... Figure 1 As shown, the worktable base 300 is the base of the rotary table 60 and is located approximately at the center of the second device base 202 of the grinding apparatus 1. Furthermore, a cylindrical support column 320 is fixed on the worktable base 300 and erected vertically from the worktable base 300.

[0042] The turntable 60 has an annular plate shape with an opening in the center, through which a support column 320 fixed to the worktable base 300 passes. With this structure, the turntable 60 can rotate in the outer circumferential direction of the support column 320.

[0043] In detail, the chuck worktable 50 is mounted on the turntable 60. The turntable 60 is rotatably positioned at the center of the water tank 61. The water tank 61 has a rectangular bottom surface 65 and an outer wall 63 erected on the side of the bottom surface 65. An opening (not shown) is located at the center of the bottom surface 65 to allow the turntable 60 to rotate. The water tank 61 has a disc-shaped cover 62 on the turntable 60 that covers the area of ​​the opening. The upper surface of the cover 62 has an inner wall 64 that divides the upper surface of the cover 62 into four sections. Four chuck worktables 50 are respectively arranged in the areas divided by the inner wall 64. A support column 320, penetrating the turntable 60 and the cover 62, is mounted on the worktable base 300 at the center of the water tank 61. Figure 1 In the accompanying drawings, the water tank 61 is omitted to show other structures, and the chuck worktable 50 is depicted as being directly mounted on the turntable 60.

[0044] Here, the structures of the first grinding mechanism 10, the second grinding mechanism 20, and the third grinding mechanism 30, as well as the first grinding feed mechanism 70, the second grinding feed mechanism 80, and the third grinding feed mechanism 90, will be described.

[0045] like Figure 2 ( Figure 2As shown in the perspective view of the structure on the second device base 202, a first grinding mechanism 10 and a first grinding feed mechanism 70 for grinding the first grinding mechanism 10 are provided in front of the second device base 202 (on the +Y direction side).

[0046] And, as Figure 2 As shown, a second grinding mechanism 20 and a second grinding feed mechanism 80 for grinding the second grinding mechanism 20 are provided at the rear of the second device base 202, as well as a third grinding mechanism 30 and a third grinding feed mechanism 90 for grinding the third grinding mechanism 30.

[0047] In addition, Figure 2 In order to clearly show the structure of the rotary table 60, the chuck table 50, the grinding mechanisms 10, 20, 30 and the grinding feed mechanisms 70, 80 and 90, other structures are omitted.

[0048] The first grinding mechanism 10, the second grinding mechanism 20, and the third grinding mechanism 30 each include a spindle unit 41. Furthermore, the first grinding feed mechanism 70, the second grinding feed mechanism 80, and the third grinding feed mechanism 90 described above are respectively configured to perform grinding feed in the grinding feed direction on the first grinding mechanism 10, the second grinding mechanism 20, and the third grinding mechanism 30, which include the spindle unit 41.

[0049] Here, the first grinding mechanism 10, the second grinding mechanism 20, and the third grinding mechanism 30 have the same structure as each other, except that they each have a first grinding wheel 11, a second grinding wheel 21, and a third grinding wheel 31, respectively. Therefore, the structure of the first grinding mechanism 10 will be described below in relation to these structures.

[0050] Furthermore, the first grinding feed mechanism 70, the second grinding feed mechanism 80, and the third grinding feed mechanism 90 also have the same structure as each other. Therefore, the following description of these structures will focus on the structure of the first grinding feed mechanism 70 that performs the grinding feed for the first grinding mechanism 10.

[0051] The first grinding feed mechanism 70 has a prism-shaped column 101. The column 101 is located on the outside of the turntable 60 in the second device base 202.

[0052] Furthermore, the first grinding feed mechanism 70 has on one surface of the column 101: a pair of guide rails 104 extending in the grinding feed direction, i.e., the Z-axis direction; a lifting platform 116 sliding on the guide rails 104; a ball screw 115 parallel to the guide rails 104; a Z-axis motor 114 driving the ball screw 115 to rotate; and a support 110 mounted on the front surface of the lifting platform 116. The support 110 holds the first grinding mechanism 10.

[0053] The guide rail 104 guides the movement of the first grinding mechanism 10 in the grinding feed direction. The lifting table 116 is slidably mounted on the guide rail 104. A nut (not shown) is fixed to the rear surface (back side) of the lifting table 116. A ball screw 115 is screwed into this nut. The Z-axis motor 114 is connected to one end of the ball screw 115.

[0054] In the first grinding feed mechanism 70, the Z-axis motor 114 rotates the ball screw 115, thereby moving the lifting table 116 along the guide rail 104 in the Z-axis direction. Consequently, the support 110 mounted on the lifting table 116 and the first grinding mechanism 10 held on the support 110 also move together with the lifting table 116 in the Z-axis direction. Thus, the first grinding feed mechanism 70 performs grinding feed on the first grinding mechanism 10 along the Z-axis direction. Furthermore, the ball screw 115 functions as a feed axis that moves the first grinding mechanism 10 in the grinding feed direction.

[0055] The first grinding mechanism 10 includes: a spindle housing 40 fixed to a support 110; a spindle 42 rotatably held in the spindle housing 40; a spindle motor 44 that drives the spindle 42 to rotate; a grinding wheel mounting base 45 mounted on the lower end of the spindle 42; and a grinding wheel 43 detachably connected to the lower surface of the grinding wheel mounting base 45.

[0056] The spindle housing 40, the spindle 42, and the spindle motor 44 constitute the spindle unit 41 of the first grinding mechanism 10.

[0057] The spindle housing 40 is held in the support 110 in a manner that extends along the Z-axis. The spindle 42 extends in the Z-axis direction in a manner that is substantially perpendicular to the holding surface 52 of the chuck table 50 and is rotatably supported in the spindle housing 40.

[0058] The spindle motor 44 is connected to the upper end of the spindle 42. The spindle 42 can rotate about a rotation axis that passes through the center of the first grinding wheel 11 and extends along the Z-axis.

[0059] The spindle 42 passes through an opening in the base plate of the support 110, and a grinding wheel mounting seat 45 is disposed below the opening. The grinding wheel mounting seat 45 is formed into a circular plate and is fixed to the lower end (front end) of the spindle 42, rotating according to the rotation of the spindle 42. The grinding wheel mounting seat 45 supports the grinding wheel 43.

[0060] The grinding wheel 43 is formed with an outer diameter that is approximately the same as the outer diameter of the grinding wheel mounting base 45. The grinding wheel 43 includes an annular grinding wheel base (ring base) 46 formed of a metal material such as aluminum alloy. On the lower surface of the grinding wheel base 46, a plurality of first grinding tools 11 in a roughly cuboid shape are arranged and fixed in a ring around the entire circumference.

[0061] Thus, in the first grinding mechanism 10, the first grinding tool 11, which is located at the front end of the spindle 42, rotates by the rotation of the spindle 42 and grinds the wafer 5 held in the chuck table 50.

[0062] Alternatively, the first grinding feed mechanism 70 may also have a counter balance (not shown). The counter balance is mounted above the column 101 and the support 110. The counter balance is configured to lift the support 110 with a force corresponding to the weight of the support 110, including the first grinding mechanism 10. The counter balance eliminates the load on the first grinding feed mechanism 70 caused by the weight of the support 110, including the first grinding mechanism 10. Furthermore, the force generated by the counter balance is slightly larger than the aforementioned weight.

[0063] Next, the worktable base 300 and support pad 310 of the turntable 60 will be described. For example... Figure 3 As shown, the worktable base 300 has a cylindrical sidewall 303, which has a circular outer surface 301 with a diameter approximately the same as the outer diameter of the turntable 60, and a circular inner surface 302 with a diameter smaller than the outer surface 301. Furthermore, a plurality of support pads 310 are disposed on the upper surface of the worktable base 300 (the upper surface of the sidewall 303). Additionally, support columns 320 are fixedly and erected on the bottom surface (not shown) of the worktable base 300.

[0064] like Figure 3 As shown, the support pad 310 is positioned on the worktable base 300 in a position that is roughly equilateral triangular when viewed from above, and is in contact with the lower surface of the turntable 60.

[0065] The support pad 310 is connected to an air source (not shown). Furthermore, when the turntable 60 rotates, the support pad 310 sprays air from the air source onto the lower surface of the turntable 60, enabling the turntable 60 to float off the worktable base 300. In this way, the support pad 310 supports the turntable 60 in a non-contact manner, allowing it to rotate.

[0066] That is, in this embodiment, when the control unit 7 rotates the turntable 60, it uses air ejected from the support pad 310 to lift the turntable 60 from the worktable base 300, and uses the turntable motor to rotate the turntable 60. Furthermore, the side of the turntable is connected to a pulley located at the front end of the turntable motor via an annular belt. Moreover, the control unit 7 positions the chuck worktable 50 holding the wafer 5 at positions corresponding to the first grinding wheel 11 of the first grinding mechanism 10 in the first grinding region 401, the second grinding wheel 21 of the second grinding mechanism 20 in the second grinding region 402, or the third grinding wheel 31 of the third grinding mechanism 30 in the third grinding region 403.

[0067] Then, the control unit 7 stops ejecting air from the support pad 310, thereby allowing the lower surface of the turntable 60 to contact the support pad 310 for support.

[0068] Furthermore, in Figure 3 The image shows the regions on the upper surface of the wafer 5 held on the chuck stage 50 that are in contact with the lower surfaces of the first grinding wheel 11, the second grinding wheel 21 and the third grinding wheel 31, namely the first grinding region 431, the second grinding region 432 and the third grinding region 433.

[0069] The chuck stage 50 rotates in the direction of arrow 505, and the first grinding wheel 11, the second grinding wheel 21, and the third grinding wheel 31 rotate in the direction of arrow 501, thereby forming grinding regions 431-433 from the outer periphery toward the center on the upper surface of the wafer 5. The grinding regions 431-433 have a relatively fine annular fan shape.

[0070] The grinding operation of the grinding device 1 under the control of the control unit 7 will be described below.

[0071] [Maintaining process]

[0072] First, control unit 7 uses Figure 1 The robot 153 and the loading mechanism 154 shown take the wafer 5 before processing from the first box 150 and hold it on the holding surface 52 of the chuck table 50 located in the loading and unloading area 400 via the temporary worktable 156.

[0073] [First Grinding Process]

[0074] Next, the control unit 7 controls the configuration of the chuck stage 50 holding the wafer 5 relative to the first grinding mechanism 10.

[0075] That is, firstly, the control unit 7 rotates the turntable 60 to position the chuck table 50 holding the wafer 5 below the first grinding mechanism 10 in the first grinding area 401.

[0076] In the first grinding zone 401, the support 110 of the first grinding feed mechanism 70 holds the spindle unit 41 of the first grinding mechanism 10 (see reference). Figure 2 ).

[0077] Furthermore, the lower surface of the first grinding tool 11 at the front end of the spindle unit 41 is parallel to the radial portion of the conical holding surface 52 of the chuck table 50. Specifically, the tilt of the spindle unit 41 of the first grinding mechanism 10 is adjusted so that one of the two radial portions that overlap with the first grinding tool 11 when viewed from above, separated by the center of the holding surface 52, is parallel to the lower surface of the first grinding tool 11. Thus, the first grinding tool 11 forms a... Figure 3 The state of the first grinding region 431, which is an arc shape extending from the outer periphery towards the center, as shown.

[0078] In this state, the control unit 7 controls the first grinding mechanism 10 and the first grinding feed mechanism 70 to perform grinding on the wafer 5. As a result, a first grinding mark 451 with a shape corresponding to the shape of the first grinding region 431 is formed on the wafer 5. Furthermore, the first grinding mark 451 is actually formed on the entire grinding surface of the wafer 5, but... Figure 3 Only the portion that overlaps with the first grinding region 431 is shown. The second grinding mark 452 and the third grinding mark 453, which will be described later, are also shown in the same manner.

[0079] [Second grinding process]

[0080] After the first grinding process is completed, the control unit 7 controls the configuration of the chuck stage 50 holding the wafer 5 relative to the second grinding mechanism 20.

[0081] That is, firstly, the control unit 7 rotates the turntable 60 to position the chuck table 50 holding the wafer 5 below the second grinding mechanism 20 in the second grinding area 402.

[0082] In the second grinding zone 402, the support 110 of the second grinding feed mechanism 80 holds the spindle unit 41 of the second grinding mechanism 20 (see reference). Figure 2 ).

[0083] Furthermore, the lower surface of the second grinding tool 21 at the front end of the spindle unit 41 is parallel to the radius portion of the conical holding surface 52 of the chuck table 50. Specifically, the tilt of the spindle unit 41 of the second grinding mechanism 20 is adjusted so that the radius portion of one of the two radius portions that is not parallel to the lower surface of the first grinding tool 11, which exists in a manner that overlaps with the second grinding tool 21 in a top view across the center of the holding surface 52, is parallel to the lower surface of the second grinding tool 21. Thus, the wafer 5 held on the holding surface 52 is formed by the second grinding tool 21. Figure 3 The second grinding region 432 is in the state of an arc shape extending from the outer periphery towards the center, as shown. That is, the second grinding mechanism 20 is arranged relative to the chuck table 50 in such a way that the second grinding region 432 intersects with the first grinding region 431.

[0084] In this state, the control unit 7 controls the second grinding mechanism 20 and the second grinding feed mechanism 80 to perform grinding on the wafer 5. As a result, a second grinding mark 452 with a shape corresponding to the shape of the second grinding region 432 is formed on the wafer 5.

[0085] Thus, in the first grinding process and the second grinding process, the first grinding mechanism 10 and the second grinding mechanism 20 are arranged relative to the chuck table 50 in such a way that the second grinding mark 452 of the wafer 5 produced by grinding by the second grinding tool 21 intersects with the first grinding mark 451 of the wafer 5 produced by grinding by the first grinding tool 11.

[0086] [Third grinding process]

[0087] After the second grinding process is completed, the control unit 7 controls the configuration of the chuck stage 50 holding the wafer 5 relative to the third grinding mechanism 30.

[0088] That is, the control unit 7 rotates the turntable 60 to position the chuck table 50 holding the wafer 5 below the third grinding mechanism 30 in the third grinding area 403.

[0089] In the third grinding zone 403, the support 110 of the third grinding feed mechanism 90 holds the spindle unit 41 of the third grinding mechanism 30 (see reference). Figure 2 ).

[0090] Furthermore, the lower surface of the third grinding tool 31 at the front end of the spindle unit 41 is parallel to the radial portion of the conical holding surface 52 of the chuck table 50. Specifically, the tilt of the spindle unit 41 of the third grinding mechanism 30 is adjusted so that one of the two radial portions that are not parallel to the lower surface of the second grinding tool 21, which overlaps with the third grinding tool 31 in a plan view across the center of the holding surface 52, is parallel to the lower surface of the third grinding tool 31. Thus, the wafer 5 held on the holding surface 52 is formed by the third grinding tool 31. Figure 3 The third grinding region 433 is in an arc shape from the outer periphery toward the center, as shown. That is, the third grinding mechanism 30 is arranged relative to the chuck table 50 in such a way that the third grinding region 433 intersects with the second grinding region 432.

[0091] In this state, the control unit 7 controls the third grinding mechanism 30 and the third grinding feed mechanism 90 to perform grinding on the wafer 5. As a result, a third grinding mark 453 with a shape corresponding to the shape of the third grinding region 433 is formed on the wafer 5.

[0092] Thus, in the second and third grinding processes, the second grinding mechanism 20 and the third grinding mechanism 30 are configured relative to the chuck table 50 in such a way that the third grinding mark 453 of the wafer 5 produced by grinding by the third grinding tool 31 intersects with the second grinding mark 452 of the wafer 5 produced by grinding by the second grinding tool 21.

[0093] [Cleaning / Recycling Process]

[0094] After the third grinding process is completed, the control unit 7 rotates the rotary table 60 to position the chuck table 50 holding the wafer 5 in the loading / unloading area 400. The control unit 7 controls... Figure 1 The conveying mechanism 157 shown transports the wafer 5 to the rotary cleaning unit 265 for rotary cleaning. Afterward, the control unit 7 controls the robot 153 to move the rotary-cleaned wafer 5 into the second box 151.

[0095] As described above, in this embodiment, in the second grinding process, the second grinding mechanism 20 is arranged relative to the chuck table 50 such that the second grinding mark 452 of the wafer 5 produced by the second grinding tool 21 intersects with the first grinding mark 451 of the wafer 5. Furthermore, in the third grinding process, the third grinding mechanism 30 is arranged relative to the chuck table 50 such that the third grinding mark 453 of the wafer 5 produced by the third grinding tool 31 intersects with the second grinding mark 452 of the wafer 5.

[0096] Therefore, in the second grinding process, the wafer 5 is ground by scraping off the first grinding marks 451, and in the third grinding process, the wafer 5 is ground by scraping off the second grinding marks 452. As a result, a high-quality wafer 5 with small thickness deviation and high bending strength can be obtained.

[0097] Furthermore, during grinding with intersecting grinding marks, appropriate impact forces are applied to the second grinding wheel 21, which forms the second grinding mark 452 intersecting with the first grinding mark 451, and the third grinding wheel 31, which forms the third grinding mark 453 intersecting with the second grinding mark 452. This generates a spontaneous sharpening effect and maintains the grinding force. Therefore, the grinding force of the second grinding wheel 21 and the third grinding wheel 31 can be increased.

[0098] In addition, spindle units 41 of the first grinding mechanism 10, the second grinding mechanism 20, and the third grinding mechanism 30 are respectively configured for the first grinding feed mechanism 70, the second grinding feed mechanism 80, and the third grinding feed mechanism 90 in this embodiment.

[0099] Furthermore, in this embodiment, the grinding apparatus 1 has two boxes (a first box 150 and a second box 151) for storing the wafer 5. Regarding this, the number of boxes in the grinding apparatus 1 is not limited to two; it can be one or more than three.

[0100] Furthermore, at least four chuck stages 50 that hold the wafer 5 via the holding surface 52 are configured on the rotary table 60. Additionally, at least three grinding mechanisms are configured.

[0101] For example, five chuck worktables 50 can be configured on the rotary table 60, and four grinding mechanisms can be set up. That is, it can also be like... Figure 4 As shown, the first grinding mechanism 10, the second grinding mechanism 20 and the third grinding mechanism 30 are provided together with the first grinding feed mechanism 70, the second grinding feed mechanism 80 and the third grinding feed mechanism 90, and the fourth grinding mechanism 35 is added together with the fourth grinding feed mechanism 95 that performs grinding feed on the fourth grinding mechanism 35.

[0102] Five chuck tables 50 are arranged at equal intervals in the circumferential direction on the rotary table 60. Furthermore, the first grinding mechanism 10, the second grinding mechanism 20, the third grinding mechanism 30, and the fourth grinding mechanism 35 are arranged above the four chuck tables 50.

[0103] The fourth grinding mechanism 35 has the same structure as the third grinding mechanism 30, and has a fourth grinding wheel 36. The fourth grinding wheel 36 is, for example, a grinding wheel for final fine grinding containing abrasive grains smaller than those of the third grinding wheel 31.

[0104] The fourth grinding wheel 36 is rotated to form a fourth grinding region 434 on the upper surface of the wafer 5 held in the chuck stage 50. The fourth grinding region 434 has a relatively fine annular fan shape, similar to the grinding regions 431 to 433.

[0105] In addition, Figure 4 In the diagram, arrow 501 indicates the rotation direction of grinding tools 11, 21, 31, and 36, while arrow 505 indicates the rotation direction of the chuck table 50.

[0106] In addition, Figure 4 In the example shown, the first grinding feed mechanism 70, the second grinding feed mechanism 80, the third grinding feed mechanism 90, and the fourth grinding feed mechanism 95 are also composed of a column 101 and a support 110, etc. Furthermore, the column 101 can also be a portal column having a column clamping the support 110. Additionally, in the portal column, a column is arranged to clamp the chuck table 50.

[0107] Furthermore, during the grinding of the wafer 5 using the fourth grinding mechanism 35, the rotary table 60 is rotated, and the chuck table 50 is positioned relative to the fourth grinding mechanism such that the fourth grinding mark 454 of the wafer 5 produced by the fourth grinding wheel 36 intersects with the third grinding mark 453 of the wafer 5 produced by the third grinding wheel 31. Therefore, the wafer 5 is ground by scraping away the third grinding mark 453. This results in a high-quality wafer 5 with small thickness deviation and high bending strength. Furthermore, the grinding forces of the second grinding wheel 21, the third grinding wheel 31, and the fourth grinding wheel 36 can be increased.

[0108] In addition, in having Figure 4 The four grinding mechanisms shown can also be configured as follows: Figure 5 As shown, the orientation of the column 101 and the support 110 in the second grinding feed mechanism 80 and the fourth grinding feed mechanism 95 is changed. In this structure, it is also possible to obtain... Figure 4 The structure shown has the same effect.

Claims

1. A grinding apparatus comprising: A turntable, configured to rotate about its center axis; A chuck stage, having at least four chuck stages configured on the rotary table, the at least four chuck stages holding the wafer by holding it facing the wafer; A grinding mechanism, comprising at least three grinding units, grinds a wafer by bringing the lower surface of an annular grinding wheel into contact with the radial region of the wafer held by the holding surface. A grinding feed mechanism that performs grinding feed in a grinding feed direction perpendicular to the holding surface; as well as Control unit By rotating the rotary table, one of the chuck worktables is positioned on each of the grinding wheels, and the wafer held on the retaining surface is subjected to plunge grinding. At least three of these grinding mechanisms include: The first grinding mechanism grinds the wafer by bringing the lower surface of the first grinding tool, which is arranged in a ring on the first grinding wheel, into contact with the first arc-shaped first grinding area of ​​the wafer from the outer periphery toward the center. The second grinding mechanism grinds the wafer by bringing the lower surface of the second grinding tool, which is arranged in a ring on the second grinding wheel, into contact with the arc-shaped second grinding area of ​​the wafer from the outer periphery toward the center. as well as The third grinding mechanism grinds the wafer by bringing the lower surface of the third grinding tool, which is arranged in a ring on the third grinding wheel, into contact with the arc-shaped third grinding area of ​​the wafer from the outer periphery toward the center. The control unit rotates the first grinding wheel clockwise, and simultaneously rotates one of the associated chuck stages clockwise, so that the lower surface of the first grinding wheel contacts the first grinding area of ​​the wafer, forming multiple arc-shaped first grinding marks on the wafer along a circumferential direction centered on the wafer's center. The control unit rotates the second grinding wheel counterclockwise, while simultaneously rotating one of the associated chuck stages counterclockwise, causing the lower surface of the second grinding wheel to contact the second grinding area of ​​the wafer, forming multiple arc-shaped second grinding marks on the wafer along a circumferential direction centered on the wafer's center. The control unit rotates the third grinding wheel clockwise, while simultaneously rotating one of the associated chuck stages clockwise, causing the lower surface of the third grinding wheel to contact the third grinding area of ​​the wafer, thus forming multiple arc-shaped third grinding marks on the wafer along a circumferential direction centered on the wafer's center. When the chuck table is positioned relative to the first grinding wheel of the first grinding mechanism, the second grinding wheel of the second grinding mechanism, and the third grinding wheel of the third grinding mechanism by rotating the rotary table, the rotation center of the rotary table and the rotation center of the chuck table are aligned with the rotation centers of the first, second, and third grinding wheels on the same straight line. When the chuck stage holding the wafer is positioned on the second grinding wheel of the second grinding mechanism, the first grinding area and the second grinding area of ​​the wafer are symmetrical about the straight line connecting the rotation center of the rotary table, the rotation center of the chuck stage, and the rotation center of the second grinding wheel. The second grinding mark on the wafer produced by the grinding of the second grinding wheel intersects with the first grinding mark on the wafer produced by the grinding of the first grinding wheel. Furthermore, when the chuck stage holding the wafer is positioned on the third grinding wheel of the third grinding mechanism, the second grinding area and the third grinding area of ​​the wafer are symmetrical about the straight line connecting the rotation center of the turntable, the rotation center of the chuck stage, and the rotation center of the third grinding wheel. The third grinding mark of the wafer produced by the grinding of the third grinding wheel intersects with the second grinding mark of the wafer produced by the grinding of the second grinding wheel.

2. A method for grinding a wafer, wherein the wafer is ground using the grinding apparatus of claim 1, wherein, The grinding method for this wafer includes the following steps: In the first grinding process, the lower surface of the first grinding tool is brought into contact with the first grinding area of ​​the wafer held by the chuck table to grind the wafer. In the second grinding process, after the first grinding process, the lower surface of the second grinding tool is brought into contact with the second grinding area of ​​the wafer to grind the wafer, so that the second grinding mark generated by the grinding of the second grinding tool intersects with the first grinding mark generated on the wafer in the first grinding process. as well as In the third grinding process, after the second grinding process, the lower surface of the third grinding tool is brought into contact with the third grinding area of ​​the wafer to grind the wafer, so that the third grinding mark generated by the grinding of the third grinding tool intersects with the second grinding mark generated on the wafer in the second grinding process.

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