Grinding device

Abstract

To provide a grinding device including a cleaning unit which can easily clean an entire area of a holding surface of a chuck table which holds a workpiece on the holding surface having a shape corresponding to a side surface of a circular cone.SOLUTION: A grinding device includes: a chuck table for holding a workpiece on a holding surface having a shape corresponding to a side surface of a circular cone; a grinding unit for grinding the workpiece held by the holding surface; and a cleaning unit for removing foreign objects adhering to the holding surface. The cleaning unit includes: cleaning grind stones each having a cleaning surface; a pressing mechanism for pressing the cleaning surfaces to the holding surface; and a revolving mechanism for revolving the cleaning surfaces around a rotation axis separated from a center of each cleaning surface. In the grinding device, the cleaning surfaces are revolved by the revolving mechanism with the cleaning surfaces pressed to the holding surface with the pressing mechanism to remove foreign objects from the holding surface while changing an inclination of each cleaning surface so that the inclination follows an inclination of an area, to which the cleaning surface is pressed, of the holding surface.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] Chips of devices such as ICs (Integrated Circuits) are essential components in various electronic devices such as mobile phones and personal computers. Such chips are manufactured, for example, by thinning a workpiece such as a wafer having multiple devices formed on its front side and then dividing the workpiece along the boundaries of the multiple devices. One method for thinning the workpiece is to grind the back side of the workpiece in a grinding device.

[0003] In the grinding device, the workpiece is ground while being held on the holding surface of the chuck table. The chuck table generally has a frame body with a recess formed on the holding surface side and a porous plate fixed in the recess. The frame body also has a flow path formed therein that communicates with the porous plate, and the flow path can communicate with a suction source and a fluid supply source.

[0004] When the suction source communicating with the porous plate is operated while the workpiece is placed on the holding surface of the chuck table, the flow path becomes negative pressure. As a result, the workpiece is sucked and held on the holding surface of the chuck table. When the workpiece is to be removed from the holding surface of the chuck table, the flow path is returned to normal pressure by operating the fluid supply source communicating with the porous plate.

[0005] When a workpiece held on the holding surface of the chuck table is ground, chips (grinding chips) of the workpiece are generated, and these chips may be sucked into the chuck table and remain on the porous plate as foreign matter. When the flow path is returned to normal pressure, the foreign matter remaining on the porous plate may be blown out of the porous plate and adhere to the holding surface of the chuck table.

[0006] When a workpiece held on the holding surface of the chuck table is ground via foreign matter, it is difficult to make the thickness of the workpiece uniform. In light of this, a grinding device has been proposed that is provided with a cleaning unit (foreign matter removal tool) for removing foreign matter adhering to the holding surface of the chuck table (see, for example, Patent Document 1).

[0007] Specifically, the cleaning unit is composed of a circular grindstone and an annular brush surrounding the circular grindstone. In the grinding device, the circular grindstone and the annular brush are pressed against the holding surface of the chuck table to remove foreign matter adhering to the holding surface. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2015-30081 A Summary of the Invention [Problem to be solved by the invention]

[0009] The holding surface of the chuck table provided in the grinding machine generally has a shape corresponding to the side surface of a cone, and therefore it is not easy to press the circular grindstone and annular brush included in the cleaning unit evenly against the entire holding surface, i.e., to clean the holding surface so as to remove all of the foreign matter adhering to the holding surface.

[0010] In view of this, an object of the present invention is to provide a grinding apparatus having a chuck table that holds a workpiece on a holding surface shaped to correspond to the side of a cone, and a cleaning unit that can easily clean the entire holding surface. [Means for solving the problem]

[0011] According to the present invention, a grinding device for grinding a workpiece is provided, the grinding device comprising: a chuck table for holding the workpiece on a holding surface having a shape corresponding to the side of a cone; a grinding unit for grinding the workpiece held on the holding surface; and a cleaning unit for removing foreign matter adhering to the holding surface, the cleaning unit including a cleaning stone having a cleaning surface, a pressing mechanism for pressing the cleaning surface against the holding surface, and a rotating mechanism for rotating the cleaning surface around a rotation axis spaced from the center of the cleaning surface, and the grinding device removes the foreign matter from the holding surface while changing the inclination of the cleaning surface to follow the inclination of the area of ​​the holding surface against which the cleaning surface is pressed.

[0012] Further, preferably, the cleaning unit further includes an elastic member for applying a reaction force to the cleaning stone, and when the cleaning surface is rotated by the rotating mechanism while the pressing mechanism presses the cleaning surface against the holding surface, the elastic member is compressed, thereby changing the inclination of the cleaning surface to follow the inclination of the region.In addition, preferably, the cleaning unit further includes a second cleaning stone having a second cleaning surface located on the opposite side of the cleaning surface from the rotation axis, and the second cleaning surface is pressed against the holding surface together with the cleaning surface by the pressing mechanism, and rotated together with the cleaning surface by the rotating mechanism. Effect of the Invention

[0013] In the present invention, when removing foreign matter adhering to the holding surface of a chuck table which holds a workpiece on a holding surface shaped to correspond to the side of a cone, the cleaning surface of the cleaning stone is pressed against the holding surface while rotating the cleaning surface, thereby changing the inclination of the cleaning surface to follow the inclination of the area of ​​the holding surface against which the cleaning surface is pressed.

[0014] That is, in the present invention, the inclination of the cleaning surface during rotation changes according to the inclination of the area of ​​the holding surface of the chuck table against which the cleaning surface of the cleaning grindstone is pressed. In this case, the cleaning surface of the cleaning grindstone can be pressed against a wide area of ​​the holding surface of the chuck table. Therefore, in the present invention, it is possible to easily clean the entire holding surface of the chuck table. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view that illustrates an example of a grinding device. [Diagram 2] FIG. 2 is a schematic diagram illustrating a chuck table and components that can communicate with the chuck table. [Diagram 3] FIG. 3 is a partial cross-sectional rear view diagrammatically illustrating components of the cleaning unit. [Figure 4] FIG. 4 is a partial cross-sectional side view that illustrates components of the cleaning unit. [Diagram 5] 5(A) and 5(B) are each a partial cross-sectional side view that typically illustrates how foreign matter adhering to the holding surface of the chuck table is removed by the cleaning unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] An embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a perspective view showing a schematic example of a grinding device. Note that the X-axis direction and the Y-axis direction shown in Fig. 1 are directions perpendicular to each other on a horizontal plane, and the Z-axis direction is a direction (vertical direction) perpendicular to each of the X-axis direction and the Y-axis direction.

[0017] The grinding device 2 shown in Fig. 1 includes a base 4. A rectangular parallelepiped recess 4a extending along the X-axis direction is formed on the upper surface of the base 4. Inside the recess 4a, a flat table cover 6 and a bellows-like dust-proof and drip-proof cover 8 that expands and contracts as the table cover 6 moves are provided. Also, above the table cover 6, a chuck table 10 for holding the workpiece 1 is provided.

[0018] The workpiece 1 is made of a semiconductor material such as silicon and has a wafer 11 on whose front surface 11a a plurality of devices are formed. A protective tape 13 made of, for example, resin is attached to the front surface 11a of the wafer 11 to prevent damage to the devices when the back surface 11b of the wafer 11 is ground.

[0019] 2 is a diagram showing a schematic diagram of the chuck table 10 and components that can communicate with the chuck table 10. The chuck table 10 has a disk-shaped frame 12 made of, for example, ceramics. The frame 12 has a disk-shaped bottom wall 12a and a cylindrical side wall 12b standing upright from the outer periphery of the bottom wall 12a. That is, a disk-shaped recess defined by the bottom wall 12a and the side wall 12b is formed on the upper surface side of the frame 12.

[0020] A disk-shaped porous plate 14 made of porous ceramics or the like is fixed in this recess. The upper surface of the side wall 12b of the frame 12 and the upper surface of the porous plate 14 have a shape corresponding to the side surface of the cone and function as a holding surface for holding the workpiece 1. The bottom wall 12a is formed with a flow path 12c that opens at the bottom surface of the recess and penetrates the bottom wall 12a.

[0021] The flow path 12c is connected to a suction source 18 via a valve 16a, and is also connected to a fluid supply source 20 via a valve 16b. The suction source 18 includes, for example, an ejector. The fluid supply source 20 includes, for example, a tank for storing high-pressure gas, a filter for removing foreign matter mixed in the gas supplied from the tank, and a regulator for adjusting the pressure of the gas supplied from the tank.

[0022] When holding the workpiece 1 on the holding surface of the chuck table 10, first, the workpiece 1 is placed on the holding surface of the chuck table 10 with the protective tape 13 facing down. Then, the valve 16a is opened while the suction source 18 is operated. This creates a negative pressure in the flow path 12c. As a result, the workpiece 1 is sucked to the holding surface of the chuck table 10 and held thereon.

[0023] Furthermore, the chuck table 10 is connected to an X-axis direction moving mechanism (not shown). This X-axis direction moving mechanism includes, for example, a ball screw and a motor connected to the ball screw. When this X-axis direction moving mechanism is operated, the chuck table 10 moves along the X-axis direction. In addition, accompanying this movement, the table cover 6 moves along the X-axis direction and the dust-proof and drip-proof cover 8 expands and contracts.

[0024] The chuck table 10 is also connected to a rotation mechanism (not shown). This rotation mechanism includes, for example, a motor and a pulley. When this rotation mechanism is operated, the chuck table 10 rotates about a straight line passing through the center of the holding surface of the chuck table 10 as a rotation axis.

[0025] The chuck table 10 is also connected to an inclination adjustment mechanism (not shown) via bearings (not shown) or the like. This inclination adjustment mechanism includes two movable shafts and one fixed shaft that are arranged at approximately equal angular intervals along the circumferential direction of the chuck table 10. When at least one of the two movable shafts partially raises and lowers the table base and the chuck table 10, the inclination of the rotation axis of the chuck table 10 is adjusted.

[0026] 1, a rectangular pillar-shaped support structure 22 is provided in an area located behind the recess 4a on the upper surface of the base 4. A Z-axis direction movement mechanism 24 is provided on the front surface of the support structure 22. The Z-axis direction movement mechanism 24 has a pair of guide rails 26 each extending along the Z-axis direction.

[0027] A moving plate 28 is provided in front of each of the pair of guide rails 26 in a manner that allows it to slide along the pair of guide rails 26. A screw shaft 30 extending along the Z-axis direction is disposed between the pair of guide rails 26. A motor 32 for rotating the screw shaft 30 is connected to the upper end of the screw shaft 30.

[0028] A nut (not shown) that houses a large number of balls that circulate in response to the rotation of the screw shaft 30 is provided on the outer circumferential surface of the screw shaft 30 on which the screw threads are formed, forming a ball screw. This nut is fixed to the rear surface of the moving plate 28. Therefore, when the screw shaft 30 is rotated by the motor 32, the moving plate 28 moves together with the nut along the Z-axis direction.

[0029] A grinding unit 34 is provided in front of the moving plate 28. This grinding unit 34 has a cylindrical support member 36 fixed to the front surface of the moving plate 28. A cylindrical spindle housing 38 extending along the Z-axis direction is provided inside the support member 36.

[0030] A spindle 40 extending along the Z-axis direction is rotatably housed inside the spindle housing 38. A motor (not shown) connected to the base end (upper end) of the spindle 40 is also housed in the spindle housing 38. The spindle 40 protrudes downward through a through hole formed in the bottom of the spindle housing 38, and its lower end (tip) forms a disk-shaped mount 42.

[0031] The mount 42 has a generally flat lower surface, and a plurality of through holes are formed in its outer periphery at generally equal angular intervals along the circumferential direction of the mount 42. A grinding wheel 46 is attached to the mount 42 by using bolts 44 inserted into each of the through holes. The grinding wheel 46 includes an annular wheel base 48 made of a metal material such as stainless steel.

[0032] A plurality of grinding wheels 50 are arranged in a circular pattern on the underside of the wheel base 48. Each of the grinding wheels 50 contains a binder such as vitrified or resinoid, and abrasive grains such as diamond dispersed in the binder. The abrasive grains are exposed on the underside of each of the grinding wheels 50, and the underside functions as a grinding surface for grinding the workpiece 1.

[0033] Furthermore, a grinding fluid supply unit is provided near the grinding unit 34 for supplying grinding fluid (e.g., water) to the surface of the workpiece 1 (specifically, the back surface 11b of the wafer 11) when the workpiece 1 is ground by multiple grinding wheels 50.

[0034] When grinding the workpiece 1 held on the holding surface of the chuck table 10, first, the X-axis direction movement mechanism connected to the chuck table 10 is operated so that the center of the holding surface of the chuck table 10 is positioned directly below the trajectory of the multiple grinding wheels 50 when the spindle 40 is rotated.

[0035] Next, a motor connected to the base end of the spindle 40 is operated to rotate the grinding wheel 46, and a rotation mechanism connected to the chuck table 10 is operated to rotate the chuck table 10. Note that the rotation direction of the grinding wheel 46 and the rotation direction of the chuck table 10 may be the same or opposite to each other.

[0036] Next, while both the grinding wheel 46 and the chuck table 10 are rotating, the motor 32 is operated to lower the grinding wheel 46 until the grinding surfaces of the multiple grinding wheels 50 contact the surface of the workpiece 1. As a result, the workpiece 1 is ground by the multiple grinding wheels 50.

[0037] During this grinding, a grinding fluid supply unit supplies grinding fluid to the surface of the workpiece 1. Most of the grinding debris generated by this grinding is washed away from the holding surface of the chuck table 10, but some of it passes through the interface between the workpiece 1 and the chuck table 10 and is sucked into the chuck table 10, remaining on the porous plate 14 as foreign matter.

[0038] The foreign matter remaining on the porous plate 14 in this manner is blown out from the porous plate 14 when the workpiece 1 is carried out from the chuck table 10. That is, when the operation of the suction source 18 is stopped and the valve 16a is closed, and then the valve 16b is opened while the fluid supply source 20 is operated, the flow path 12c returns to normal pressure and the foreign matter is blown out from the porous plate 14.

[0039] Such foreign matter may adhere to the holding surface of the chuck table 10. The grinding device 2 is provided with a cleaning unit 52 for removing such foreign matter from the holding surface of the chuck table 10. This cleaning unit 52 has a pair of support structures 54, each of which has a rectangular prism shape.

[0040] The pair of support structures 54 are disposed to sandwich the recess 4a in a plan view. A base end of a connecting member 56 is fixed to the upper end of the surface of each support structure 54 facing the recess 4a, and a tip end of each connecting member 56 is fixed to the side of a flat support plate 58. A cover 60 is fixed to the rear surface of this support plate 58.

[0041] FIG. 3 is a partially sectional rear view that shows components of the cleaning unit 52 provided inside and below the cover 60, and FIG. 4 is a partially sectional side view that shows these components.

[0042] A pressing mechanism 62 is provided inside the cover 60 for pressing cleaning surfaces of cleaning grindstones 72a and 72b (described later) against the holding surface of the chuck table 10. The pressing mechanism 62 is, for example, an air cylinder having a cylinder tube 62a extending along the Z-axis direction and a rod 62b that can be pushed downward from the cylinder tube 62a.

[0043] The rod 62b has a main body portion, the upper side of which can be accommodated in the cylinder tube 62a, and a tip portion extending rearward from the lower end of the main body portion. A support member 64 is fixed to the tip portion of the rod 62b. The support member 64 has a side portion fixed to the tip portion of the rod 62b, and a bottom portion extending rearward from the lower end of the side portion.

[0044] A turning mechanism 66 for turning the cleaning surface around a rotation axis A spaced apart from the center of the cleaning surface of the cleaning grindstones 72a and 72b (described later) is provided at the bottom of the support member 64. The turning mechanism 66 has a motor 66a provided on the bottom of the support member 64, and a shaft 66b that passes through a through-hole 64a penetrating the bottom of the support member 64 along the Z-axis direction and has an upper end connected to the motor 66a.

[0045] The lower end of the shaft 66b is fixed to the center of a disk-shaped rotating member 68. The rotating member 68 has four through holes formed therein that pass through the rotating member 68 along the Z-axis direction and through which the bolts 70a, 70b, 70c, and 70d are respectively inserted.

[0046] The two through holes through which the bolt 70a or the bolt 70b is passed are formed to be aligned in a predetermined direction (i.e., along the radial direction of the rotating member 68) as viewed from the center of the rotating member 68 (i.e., the rotation axis A). The through holes through which the bolts 70c or the bolts 70d are passed are formed to be aligned in a direction opposite to the predetermined direction as viewed from the center of the rotating member 68.

[0047] Furthermore, the distance between the center of the rotating member 68 and the through hole through which the bolt 70a is passed is approximately equal to the distance between the center of the rotating member 68 and the through hole through which the bolt 70c is passed. Similarly, the distance between the center of the rotating member 68 and the through hole through which the bolt 70b is passed is approximately equal to the distance between the center of the rotating member 68 and the through hole through which the bolt 70d is passed.

[0048] The two bolts 70a, 70b are screwed into two screw holes formed in the upper surface of the cleaning grindstone 72a, and the two bolts 70c, 70d are screwed into two screw holes formed in the upper surface of the cleaning grindstone 72b. The cleaning grindstones 72a, 72b are made of, for example, an oil grindstone, and have an elongated rectangular parallelepiped shape extending along the radial direction of the rotating member 68.

[0049] The lower surface of each of the cleaning grindstones 72a, 72b is a generally flat rectangle, and functions as a cleaning surface for removing foreign matter adhering to the holding surface of the chuck table 10. When the diameter of the holding surface of the chuck table 10 is 8 inches (200 mm), the cleaning surface has a size such that the long side is about 10 mm to 60 mm.

[0050] Each of the bolts 70a, 70b, 70c, and 70d has a cylindrical shaft portion extending along the Z-axis direction and a hexagonal head portion having a larger diameter than the shaft portion and a smaller length along the Z-axis direction. A screw thread is formed on the lower side of the shaft portion, and no screw thread is formed on the upper side. The upper side of the shaft portion of each of the bolts 70a, 70b, 70c, and 70d is passed through a through hole formed in the rotating member 68, and the lower side is screwed into a screw hole formed in the upper surface of the cleaning grindstones 72a and 72b.

[0051] The diameter of the head of each of the bolts 70a, 70b, 70c, and 70d is larger than the diameter of the through-hole formed in the rotating member 68. Therefore, each of the bolts 70a, 70b, 70c, and 70d will not fall through the through-hole. Also, the diameter of the through-hole is, for example, slightly larger than the upper side of the shaft of each of the bolts 70a, 70b, 70c, and 70d. Therefore, each of the bolts 70a, 70b, 70c, and 70d can be slightly tilted with respect to the Z-axis direction while being passed through the through-hole.

[0052] Elastic members 74a, 74b, 74c, 74d such as compression coil springs are provided around the shafts of the bolts 70a, 70b, 70c, 70d that are located between the cleaning grindstones 72a, 72b and the rotating member 68 (surrounded portions). In other words, the surrounded portions are located inside the elastic members 74a, 74b, 74c, 74d. A reaction force generated by compressing the elastic members 74a, 74b, 74c, 74d acts on the cleaning grindstones 72a, 72b and the rotating member 68.

[0053] Furthermore, a cleaning liquid supply unit (not shown) may be provided near the cleaning unit 52 to supply a cleaning liquid (e.g., water) to the holding surface of the chuck table 10 when foreign matter is removed from the holding surface of the chuck table 10 by the cleaning grindstones 72a, 72b. In the grinding device 2, the above-mentioned grinding liquid supply unit may be used as the cleaning liquid supply unit.

[0054] 5(A) and 5(B) are each a partial cross-sectional side view that typically shows the manner in which foreign matter adhering to the holding surface of the chuck table 10 is removed by the cleaning unit 52. When the cleaning unit 52 removes foreign matter adhering to the holding surface of the chuck table 10, first, the X-axis direction moving mechanism connected to the chuck table 10 is operated so that the holding surface of the chuck table 10 is positioned directly under the cleaning grindstones 72a and 72b.

[0055] Next, the turning mechanism 66 is operated to turn the cleaning surfaces of the cleaning grindstones 72a and 72b at, for example, 60 rpm, and the rotation mechanism connected to the chuck table 10 is operated to rotate the holding surface of the chuck table 10 at, for example, 60 rpm. Note that the turning direction of the cleaning surfaces of the cleaning grindstones 72a and 72b and the rotation direction of the holding surface of the chuck table 10 may be the same or opposite.

[0056] Next, the cleaning surfaces of the cleaning grindstones 72a and 72b are rotated, and the pressing mechanism 62 is operated to press the cleaning surfaces against the holding surface of the chuck table 10 while keeping the holding surface of the chuck table 10 rotated. This causes the chuck table 10 to be cleaned by the cleaning surfaces of the cleaning grindstones 72a and 72b so as to remove foreign matter from the holding surface of the chuck table 10.

[0057] At this time, the inclination of each cleaning surface of the cleaning grindstones 72a, 72b changes so as to follow the inclination of the region where the cleaning surfaces of the cleaning grindstones 72a, 72b are pressed on the holding surface of the chuck table 10. For example, in a state where the cleaning grindstone 72b is positioned in the X-axis direction as seen from the cleaning grindstone 72a in a plan view (see FIG. 5(A)), the cleaning grindstones 72a, 72b and the bolts 70a, 70b, 70c, 70d are inclined so that the long sides of the cleaning surfaces of the cleaning grindstones 72a, 72b follow the inclination of the holding surface of the chuck table 10.

[0058] Furthermore, as the cleaning surfaces of the cleaning grindstones 72a and 72b are pressed against the holding surface of the chuck table 10, the bolts 70a, 70b, 70c, and 70d are lifted up so that their heads are separated from the upper surface of the rotating member 68. In this case, the gap between the rotating member 68 and the cleaning grindstones 72a and 72b also narrows, so that the elastic members 74a, 74b, 74c, and 74d are further compressed, and the reaction force acting on the cleaning grindstones 72a and 72b becomes stronger.

[0059] Then, by rotating the cleaning grindstones 72a, 72b from the position shown in Figure 5(A) so that, for example, the cleaning grindstone 72b is positioned in the Y-axis direction when viewed in a plan view from the cleaning grindstone 72a (see Figure 5(B)), the cleaning grindstones 72a, 72b and the bolts 70a, 70b, 70c, 70d will be inclined so that the short sides of the cleaning surfaces of each cleaning grindstone 72a, 72b follow the inclination of the holding surface of the chuck table 10.

[0060] In the above-mentioned grinding device 2, when removing foreign matter adhering to the holding surface of the chuck table 10 which holds the workpiece 1 on a holding surface shaped to correspond to the side of a cone, the cleaning surfaces of each cleaning grindstone 72a, 72b are pressed against the holding surface while rotating the cleaning surface, thereby changing the inclination of the cleaning surface to follow the inclination of the area of ​​the holding surface against which the cleaning surface is pressed.

[0061] That is, in this grinding device 2, the inclination of the cleaning surface during rotation changes according to the inclination of the area of ​​the holding surface of the chuck table 10 against which the cleaning surfaces of the cleaning grindstones 72a, 72b are pressed. In this case, the cleaning surfaces of the cleaning grindstones 72a, 72b can be pressed against a wide area of ​​the holding surface of the chuck table 10. Therefore, in this grinding device 2, it becomes possible to easily clean the entire holding surface of the chuck table 10.

[0062] The grinding device 2 is one aspect of the present invention, and the grinding device of the present invention is not limited to the grinding device 2. For example, in the grinding device of the present invention, grooves may be formed on the cleaning surfaces of the cleaning grindstones 72a and 72b to facilitate removal of foreign matter from the holding surface of the chuck table 10. In addition, in the grinding device of the present invention, the number of cleaning grindstones is not limited to two, and may be one or three or more. In addition, in the grinding device of the present invention, the shape of the cleaning surface is not limited to a rectangle, and may be a square, trapezoid, sector, or the like.

[0063] In addition, the structures and methods according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention. [Explanation of symbols]

[0064] 1: Workpiece 2: Grinding equipment 4: Base (4a: recess) 6: Table cover 8: Dust-proof and water-resistant cover 10: Chuck table 11: Wafer (11a: front surface, 11b: back surface) 12: Frame (12a: bottom wall, 12b: side wall, 12c: flow path) 13: Protective tape 14: Porous plate 16a, 16b: Valve 18:Suction source 20: Fluid supply source 22:Support structure 24:Z-axis direction movement mechanism 26: Guide rail 28: Moving plate 30: Screw shaft 32: Motor 34: Grinding unit 36: Support member 38: Spindle housing 40:Spindle 42: Mount 44: Bolt 46: Grinding wheel 48: Wheel base 50: Grinding wheel 52: Cleaning unit 54: Support structure 56: Connecting member 58: Support plate 60: Cover 62: Pressing mechanism (62a: cylinder tube, 62b: rod) 64: Support member (64a: Through hole) 66: turning mechanism (66a: motor, 66b: shaft) 68: Rotating member 70a, 70b, 70c, 70d: Bolts 72a, 72b: Cleaning stone 74a, 74b, 74c, 74d: Elastic member

Claims

1. A grinding apparatus for grinding a workpiece, comprising: a chuck table for holding the workpiece on a holding surface having a shape corresponding to a side surface of a cone; a grinding unit for grinding the workpiece held on the holding surface; a cleaning unit for removing foreign matter adhering to the holding surface, The cleaning unit comprises: A cleaning stone having a cleaning surface; a pressing mechanism for pressing the cleaning surface against the holding surface; a pivot mechanism for pivoting the cleaning surface about an axis of rotation spaced from a center of the cleaning surface; The grinding device removes the foreign matter from the holding surface by rotating the cleaning surface using the rotating mechanism while pressing the cleaning surface against the holding surface using the pressing mechanism, thereby changing the inclination of the cleaning surface to follow the inclination of the area of ​​the holding surface against which the cleaning surface is pressed.

2. The cleaning unit further includes an elastic member for applying a reaction force to the cleaning stone, 2. The grinding device according to claim 1, wherein the inclination of the cleaning surface is changed to follow the inclination of the region by compressing the elastic member when the cleaning surface is rotated by the rotating mechanism while the pressing mechanism presses the cleaning surface against the holding surface.

3. The cleaning unit further includes a second cleaning stone having a second cleaning surface located on an opposite side to the cleaning surface as viewed from the rotation axis; 3. The grinding device according to claim 1, wherein the second cleaning surface is pressed against the holding surface together with the cleaning surface by the pressing mechanism, and is rotated together with the cleaning surface by the rotating mechanism.

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