Grinding method

Abstract

The present application provides a grinding method which can suppress the vibration of a chuck table during creep feed grinding without providing a mechanism for fixing a spindle connected to the chuck table in a grinding device. When grinding a workpiece using creep feed grinding, the lower surface of the protruding portion of the spindle connected to the chuck table is brought into contact with the housing. That is, creep feed grinding is performed in a state where the lower surface of the protruding portion of the spindle is in contact with the housing. In this case, when creep feed grinding is performed on the workpiece held by suction by the chuck table, the friction force generated on the lower surface side of the protruding portion of the spindle functions as a resistance to the vibration of the chuck table. Therefore, the vibration of the chuck table during creep feed grinding can be suppressed.

Description

TECHNICAL FIELD

[0001] The present application relates to a grinding method. BACKGROUND

[0002] Chips of semiconductor devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) are indispensable constituent elements in various electronic devices such as mobile phones and personal computers. Such chips are manufactured, for example, by dividing a wafer on which a large number of semiconductor devices are formed on a front surface in regions containing each semiconductor device.

[0003] In recent years, in order to miniaturization and weight reduction of chips and the like, a wafer is thinned before being divided in many cases. As a method of thinning a wafer, for example, grinding by a grinding device can be given, the grinding device having a chuck table that attracts and holds a lower surface side of a wafer with a holding surface, and a grinding wheel that is provided above the chuck table and has a plurality of grinding stones that are arranged discretely in a ring shape.

[0004] In such a grinding device, a workpiece such as a wafer is thinned by a grinding method called plunge grinding in many cases. In this grinding method, first, the chuck table and the grinding wheel are rotated in a state in which the chuck table is positioned below the grinding wheel.

[0005] And, in a state in which the chuck table and the grinding wheel are rotated, the chuck table and the grinding wheel are relatively moved in a vertical direction in a manner that lower surfaces of the plurality of grinding stones come into contact with an upper surface of the workpiece. Thereby, the entire upper surface side of the workpiece is ground by the lower surfaces of the plurality of grinding stones. In addition, by continuing to relatively move the chuck table and the grinding wheel in the vertical direction, a portion having a prescribed thickness of the upper surface side of the workpiece is ground to thin the workpiece.

[0006] In addition, in such a grinding device, a workpiece is sometimes thinned by a grinding method called creep feed grinding (for example, refer to Patent Literature 1). In this grinding method, first, the grinding wheel is rotated in a state in which the chuck table and the grinding wheel are apart in a horizontal direction and lower surfaces of the plurality of grinding stones are positioned lower than an upper surface of the workpiece and higher than a lower surface of the workpiece.

[0007] Also, while the grinding wheel is kept rotating, the chuck table and the grinding wheel are relatively moved in the horizontal direction in a manner that the outer side surfaces of the plurality of grinding tools contact the side surface of the workpiece. Thus, the end portion of the upper surface side of the workpiece having a prescribed thickness is ground by the outer side surfaces of the plurality of grinding tools. Also, by continuously relatively moving the chuck table and the grinding wheel in the horizontal direction, the entire upper surface side of the workpiece is ground to thin the workpiece.

[0008] Patent Document 1: Japanese Patent Application Publication No. 2005-28550

[0009] When plunge grinding is performed in the grinding device, the chuck table needs to be rotated as described above. Therefore, the chuck table is usually linked to the main shaft that can be rotated in a manner that the chuck table rotates together with the main shaft.

[0010] Here, in the case where the creep feed grinding is performed in such a grinding device, larger vibration occurs on the chuck table than in the case where the plunge grinding is performed. Also, in the grinding of the workpiece, in the case where vibration occurs on the chuck table, it is possible that larger unevenness and cracks are formed on the ground surface of the ground workpiece.

[0011] Therefore, in the known grinding device that is used for both the plunge grinding and the creep feed grinding, a mechanism for fixing the main shaft linked to the chuck table (for example, a mechanism for fixing the main shaft using a screw or the like) is usually provided. However, such a mechanism can complicate the configuration of the grinding device and increase the manufacturing cost of the grinding device. SUMMARY

[0012] In view of this point, an object of the present application is to provide a grinding method that can suppress the vibration occurring on the chuck table at the time of the creep feed grinding without providing such a mechanism in the grinding device.

[0013] According to the present application, there is provided a grinding method of grinding a workpiece using a grinding device having: a chuck table having a holding surface that holds the workpiece; a table base on an upper portion of which the chuck table is installed; a first spindle having a main body portion that is suspended from a center of a lower portion of the table base and a protruding portion that protrudes outward from a side surface of the main body portion; a housing that surrounds the side surface of the main body portion and has a communication passage that is opened at a position opposite to a lower surface of the protruding portion in an inside of the housing; a fluid supply source that supplies a fluid to the communication passage; a second spindle having a lower end portion at which a grinding wheel having a plurality of grinding stones that grind the workpiece is installed; a vertical direction moving mechanism that relatively moves the chuck table and the grinding wheel in a vertical direction; and a horizontal direction moving mechanism that relatively moves the chuck table and the grinding wheel in a horizontal direction that is perpendicular to the vertical direction, characterized by comprising: a selection step of selecting whether to grind the workpiece by plunge grinding in which the chuck table and the grinding wheel are rotated in a state in which the chuck table is positioned below the grinding wheel, and then the workpiece is ground while relatively moving the chuck table and the grinding wheel in the vertical direction while rotating the chuck table and the grinding wheel, or by creep feed grinding in which the grinding wheel is rotated in a state in which the chuck table and the grinding wheel are distanced in the horizontal direction and lower surfaces of the plurality of grinding stones are positioned lower than an upper surface of the workpiece and higher than a lower surface of the workpiece, and then the workpiece is ground while relatively moving the chuck table and the grinding wheel in the horizontal direction while rotating the grinding wheel; a separation step of separating the lower surface of the protruding portion from the housing by supplying the fluid from the fluid supply source to the communication passage in a case in which the plunge grinding is selected by the selection step; and a contact step of bringing the lower surface of the protruding portion into contact with the housing without supplying the fluid from the fluid supply source to the communication passage in a case in which the creep feed grinding is selected by the selection step.

[0014] In the present application, the protruding portion of the spindle that is linked to the chuck table is brought into contact with the housing when the workpiece is ground by the creep feed grinding. In this case, the friction force that is generated on the lower surface side of the protruding portion of the spindle functions as a resistance to vibration of the chuck table when the workpiece that is suction-held by the chuck table is subjected to the creep feed grinding. Therefore, in the present application, the vibration of the chuck table when the creep feed grinding is performed is suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a perspective view schematically showing an example of a grinding device.

[0016] Figure 2 is a partial cross-sectional side view schematically showing a part of a configuration element of an example of a grinding device.

[0017] Figure 3 is a flowchart schematically showing an example of a grinding method.

[0018] Explanation of Reference Signs

[0019] 2: grinding device; 4: base (4a: opening); 6: table cover; 8: chuck table; 10: frame (10a: recess); 12: multiwell plate (12a: upper surface); 14: table base; 16: spindle (16a: main body portion, 16b: protruding portion); 18: housing (18a: recess, 18b: protruding portion, 18c: communication path); 20: driven pulley (20a: shaft, 20b: flange); 22: belt; 24: driving pulley; 26: motor; 28: dust and drip-proof cover; 30: operation panel; 32: support structure; 34: Z-axis direction moving mechanism (vertical direction moving mechanism); 36: Z-axis guide rail; 38: Z-axis moving plate; 40: screw shaft; 42: motor; 44: support member; 46: grinding unit; 48: spindle housing; 50: spindle; 52: motor; 54: grinding wheel mount; 56: grinding wheel; 58: grinding wheel base; 60: grinding tool. DETAILED DESCRIPTION

[0020] An embodiment of the present application will be described with reference to the drawings. Figure 1 is a perspective view schematically showing an example of a grinding device commonly used in plunge grinding and creep feed grinding. In addition, Figure 1 The X-axis direction (front-rear direction) and the Y-axis direction (left-right direction) shown are directions perpendicular to each other on a horizontal plane, and the Z-axis direction (up-down direction) is a direction perpendicular to the X-axis direction and the Y-axis direction (vertical direction).

[0021] Figure 1 The grinding device 2 shown has a base 4 that supports each configuration element. An opening 4a having a long side portion extending along the X-axis direction is formed on the upper surface of the base 4. Inside the opening 4a, an X-axis direction moving mechanism (not shown) (horizontal direction moving mechanism) of a ball screw type is disposed. The X-axis direction moving mechanism has a pair of guide rails (not shown) extending along the X-axis direction.

[0022] An X-axis moving plate (not shown) is joined to the upper portions of the pair of guide rails in a manner so as to be slidable along the pair of guide rails. In addition, a screw shaft (not shown) extending along the X-axis direction is disposed between the pair of guide rails. An electric motor (not shown) for rotating the screw shaft is joined to one end portion of the screw shaft.

[0023] A nut portion (not shown) in which a ball that rolls on the surface of the screw shaft that rotates is accommodated is provided on the surface of the screw shaft on which a helical groove is formed, and a ball screw is constituted. That is, when the screw shaft rotates, the ball circulates in the nut portion, and the nut portion moves in the X-axis direction.

[0024] In addition, the nut portion is fixed to the lower surface side of the X-axis moving plate (not shown). Therefore, if the screw shaft is rotated by the motor, the X-axis moving plate moves in the X-axis direction together with the nut portion.

[0025] A table cover 6 is provided on the X-axis moving plate. In addition, a chuck table 8 is provided on the table cover 6. Here, reference is made to Figure 2 The chuck table 8 and the like will be described. In addition, Figure 2 is a partially cutaway side view schematically showing a part of the constituent elements of the grinding device 2 (the chuck table 8 and the like).

[0026] The chuck table 8 has, for example, a frame 10 formed of a metal material such as stainless steel or ceramic. The frame 10 has a bottom wall in a disc shape and a side wall in a circular ring shape that extends upward from the outer peripheral portion of the bottom wall. Further, a recess 10a is partitioned on the upper surface side of the frame 10 by the side wall.

[0027] A disc-shaped porous plate 12 formed of ceramic is fixed in the recess 10a. The upper surface 12a (holding surface of the chuck table 8) of the porous plate 12 can be configured in a shape corresponding to the side surface of a cone (in a conical shape), or can be flat. A disc-shaped table base 14 that mounts the chuck table 8 in a replaceable manner is provided in the lower portion of the chuck table 8.

[0028] The lower surface side of the porous plate 12 is communicated with a suction source (not shown) such as an ejector via a flow path (not shown) and a valve (not shown) provided inside the frame 10 and the table base 14, for example. If the valve is opened in a state in which the suction source is operating, a negative pressure can be generated on the upper surface 12a (holding surface of the chuck table 8) of the porous plate 12, and a workpiece is suction-held.

[0029] The upper portion of a spindle (first spindle) 16 is fixed to the lower portion of the table base 14. Further, when a motor 26 described later operates, the chuck table 8, the table base 14, and the spindle 16 rotate in the direction of the arrow A shown in the drawing about a straight line that passes through the center of the holding surface of the chuck table 8 and that is in the Z-axis direction or slightly inclined from the Z-axis direction as a rotation axis. Figure 2

[0030] ​The spindle 16 has a cylindrical main body portion 16a which is lowered from the center of the lower portion of the table base 14, and a ring-shaped protruding portion 16b which protrudes outward from the side surface of the main body portion 16a. The spindle 16 is housed in a tubular housing 18 which is fixed to the X-axis moving plate by a support mechanism (not shown).

[0031] A recessed portion 18a having a shape corresponding to the protruding portion 16b is provided on the inner peripheral surface of the housing 18. For example, the bottom surface of the recessed portion 18a (a surface which is substantially parallel to the Z-axis direction, a surface which extends in the up-down direction in the Figure 2 center of the spindle 16, and the side surface of the protruding portion 16b become concentric circles centered on the rotational axis of the chuck table 8 or the like when viewed from above. In this case, the diameter of the bottom surface of the recessed portion 18a when viewed from above is slightly longer than the diameter of the side surface of the protruding portion 16b when viewed from above.

[0032] In addition, the width of the bottom surface of the recessed portion 18a in the direction of the rotational axis of the chuck table 8 or the like is wider than the width of the side surface of the protruding portion 16b in the direction. Also, the recessed portion 18a surrounds the upper surface, the side surface, and the lower surface of the protruding portion 16b.

[0033] The inner diameter of the inner peripheral surface of the housing 18 other than the recessed portion 18a when viewed from above is slightly longer than the diameter of the main body portion 16a when viewed from above. Also, the inner peripheral surface surrounds the side surface of the main body portion 16a. In addition, a convex portion 18b is provided on the outer peripheral surface of the housing 18.

[0034] In addition, a plurality of communication paths 18c are provided inside the housing 18. One end of each of the plurality of communication paths 18c is opened at the convex portion 18b, and is connected to a fluid supply source (not shown), for example, via a pipe (not shown) and a valve (not shown). The fluid supply source is capable of supplying a gas such as air or a liquid such as water to one end of each of the plurality of communication paths 18c.

[0035] The communication paths 18c branch inside the housing 18, and the front ends of the branched communication paths 18c are respectively opened at positions of the recessed portion 18a which are opposite the upper surface and the lower surface of the protruding portion 16b. Therefore, when fluid is supplied from the fluid supply source to the plurality of communication paths 18c, the fluid is supplied to the upper surface and the lower surface of the protruding portion 16b.

[0036] Also, when fluid exceeding a prescribed pressure is supplied to the lower surface of the protruding portion 16b, the lower surface of the protruding portion 16b separates from the recessed portion 18a. In addition, the fluid supplied to the upper surface and the lower surface of the protruding portion 16b passes through the gap between the spindle 16 and the housing 18 and is discharged to the outside of the grinding device 2.

[0037] On the other hand, in a case where no fluid is supplied to the lower surface of the protrusion 16b, the lower surface of the protrusion 16b is in contact with the housing 18 in the recess 18a due to the action of gravity. In this case, the spindle 16 is supported to the X-axis moving plate by means of the housing 18.

[0038] That is, in the spindle 16, in a case where the fluid is supplied from the fluid supply source to the plurality of communication passages 18c at a pressure exceeding a prescribed pressure, the lower surface of the protrusion 16b is separated from the recess 18a of the housing 18, and, in a case where no fluid is supplied, the lower surface of the protrusion 16b is in contact with the recess 18a of the housing 18.

[0039] A driven pulley 20 is fixed to the lower portion of the main body portion 16a. The driven pulley 20 has a shaft 20a, and flanges 20b provided to the upper end portion and the lower end portion of the shaft 20a, respectively. Further, a belt 22 to which a prescribed tension is imparted is wound around the shaft 20a.

[0040] A transmission pulley 24 is provided in the vicinity of the driven pulley 20 so as to be separated from the driven pulley 20 in the horizontal direction. Further, the belt 22 is also wound around the transmission pulley 24. In addition, one end portion of the transmission pulley 24 is linked to a motor 26. Further, when the motor 26 is operated, the transmission pulley 24 rotates in the direction of the arrow B shown in the drawing, with a straight line along the Z-axis direction or a straight line along a direction slightly inclined from the Z-axis direction as a rotation axis. Figure 2

[0041] At this time, the belt 22 also rotates by the action of the frictional force between the transmission pulley 24 and the belt 22, and, in addition, the driven pulley 20 also rotates by the action of the frictional force between the belt 22 and the shaft 20a. As a result, the chuck table 8, the table base 14, and the spindle 16 rotate in the direction of the arrow A shown in the drawing. Figure 2

[0042] Referring again to Figure 1 to other constituent elements of the grinding device 2 will be described. A dust and drip prevention cover 28 of a bellows shape capable of extending and contracting in the X-axis direction is provided in the opening 4a in a manner so as to sandwich the table cover 6. An operation panel 30 for inputting a grinding condition and the like is provided in the vicinity of the front end of the opening 4a.

[0043] In addition, a cuboid-shaped support structure 32 extending upward is provided in the vicinity of the rear end of the opening 4a. A Z-axis direction moving mechanism (vertical direction moving mechanism) 34 is provided on the front surface side (i.e., the operation panel 30 side) of the support structure 32. The Z-axis direction moving mechanism 34 has a pair of Z-axis rails 36 extending along the Z-axis direction.

[0044] ​​A Z-axis moving plate 38 is attached to the front surface side of the pair of Z-axis rails 36 so as to be slidable along the pair of Z-axis rails 36. In addition, a screw shaft 40 extending in the Z-axis direction is disposed between the pair of Z-axis rails 36. A motor 42 for rotating the screw shaft 40 is attached to one end of the screw shaft 40.

[0045] A nut portion (not shown) in which balls rolling on the surface of the rotating screw shaft 40 are accommodated is provided on the surface of the screw shaft 40 in which a helical groove is formed, and a ball screw is constituted. That is, when the screw shaft 40 is rotated, the balls circulate in the nut portion, and the nut portion moves in the Z-axis direction.

[0046] In addition, the nut portion is fixed to the back surface side of the Z-axis moving plate 38. Therefore, if the screw shaft 40 is rotated by the motor 42, the Z-axis moving plate 38 moves in the Z-axis direction together with the nut portion.

[0047] A support 44 is provided on the front surface side of the Z-axis moving plate 38. The support 44 supports a grinding unit 46. The grinding unit 46 has a cylindrical main shaft housing 48 fixed to the support 44. A cylindrical main shaft (second main shaft) 50 extending in the Z-axis direction is partially accommodated in the main shaft housing 48 in a rotatable state.

[0048] A motor 52 for rotating the main shaft 50 is attached to the upper end portion of the main shaft 50. The lower end portion of the main shaft 50 is exposed from the main shaft housing 48, and the upper portion of a disc-shaped grinding wheel mounting seat 54 formed of a metal material such as stainless steel is fixed to the lower end portion.

[0049] A ring-shaped grinding wheel 56 having substantially the same diameter as the grinding wheel mounting seat 54 is attached to the lower portion of the grinding wheel mounting seat 54. The grinding wheel 56 has a circular ring-shaped grinding wheel base 58 formed of a metal material such as stainless steel. A plurality of grinding tools 60 are fixed to the lower surface side of the grinding wheel base 58.

[0050] The plurality of grinding tools 60 are each a rectangular parallelepiped, and are discretely disposed along the circumferential direction of the grinding wheel base 58. In addition, a nozzle (not shown) for supplying a grinding fluid such as water to the grinding surface when the workpiece is ground is provided in the vicinity or inside of the grinding wheel 56.

[0051] In addition, in the grinding device 2, when the workpiece is ground by plunge grinding, mainly the lower surfaces of the plurality of grinding tools 60 become the grinding surface for grinding the workpiece, and when the workpiece is ground by creep feed grinding, mainly the outer surfaces of the plurality of grinding tools 60 become the grinding surface for grinding the workpiece.

[0052] Therefore, a nozzle that supplies the grinding fluid to the lower surface of the plurality of grinding tools 60 and a nozzle that supplies the grinding fluid to the outer side surface of the plurality of grinding tools 60 can be respectively provided in the vicinity of or inside the grinding wheel 56.

[0053] Further, when the motor 52 is operated, the spindle 50, the wheel mounting seat 54, and the grinding wheel 56 are rotated with a straight line along the Z-axis direction or along a direction slightly inclined from the Z-axis direction as a rotation axis.

[0054] Figure 3 is a flowchart showing an example of a grinding method of the grinding apparatus 2 shown in Figure 1 A flowchart showing an example of a grinding method of the grinding apparatus 2 shown in

[0055] In a case where the grinding of the workpiece is not performed by the creep feed grinding, i.e., the grinding of the workpiece is performed by the plunge grinding (selection step (S1): No), the spindle (the spindle fixed to the table base 14) 16 for rotating the chuck table 8 is separated from the housing 18 (separation step: S11). Specifically, the fluid exceeding a prescribed pressure is supplied from the fluid supply source to one end of each of the plurality of communication paths 18c of the housing 18.

[0056] Next, the grinding of the workpiece is performed by the plunge grinding (grinding step: S12). The plunge grinding is performed, for example, in the following order. First, the workpiece is suction-held to the chuck table 8. Specifically, after the workpiece is placed on the holding surface of the chuck table 8, the valve is opened in a state where the suction source that is in communication with the flow path provided inside the frame 10 of the chuck table 8 and the table base 14 via the valve is operated.

[0057] Next, the chuck table 8 and the grinding wheel 56 are moved to a prescribed position. Specifically, the X-axis direction moving mechanism (not shown) and the Z-axis direction moving mechanism 34 are operated in such a manner that the chuck table 8 is positioned below the grinding wheel 56. Thus, any of the plurality of grinding tools 60 of the grinding wheel 56 is positioned, for example, directly above the center of the holding surface of the chuck table 8.

[0058] Next, the chuck table 8 and the grinding wheel 56 are rotated. Specifically, the motor 26 is operated so as to rotate the spindle 16, and the motor 52 is operated so as to rotate the spindle 50.

[0059] Next, the chuck table 8 and the grinding wheel 56 are relatively moved in the Z-axis direction to grind the workpiece. Specifically, the Z-axis direction moving mechanism 34 is operated so that the upper surface of the workpiece held by suction by the chuck table 8 contacts the lower surfaces of the plurality of grinding tools 60.

[0060] Thus, the entire upper surface side of the workpiece is ground by the lower surfaces of the plurality of grinding tools 60. Further, by continuing the operation of the Z-axis direction moving mechanism 34, the portion of the upper surface side of the workpiece having a prescribed thickness is ground, and the workpiece is thinned.

[0061] In this plunge grinding, the lower surface of the protruding portion 16b of the spindle 16 is separated from the housing 18 before the chuck table 8 is rotated. Thus, when the chuck table 8 is rotated, a large frictional force does not occur on the lower surface side of the protruding portion 16b of the spindle 16, and the chuck table 8 can be easily rotated.

[0062] On the other hand, in a case where grinding of the workpiece by creep feed grinding is selected (selection step (S1): Yes), the spindle (spindle fixed to the table base 14) 16 for rotating the chuck table 8 is brought into contact with the housing 18 (contact step: S21). Specifically, the supply of fluid to each of the plurality of communication paths 18c of the housing 18 from the fluid supply source is stopped.

[0063] Next, the workpiece is ground by creep feed grinding (grinding step: S22). This creep feed grinding is performed, for example, in the following order. First, the workpiece is held by suction on the chuck table 8. Specifically, after the workpiece is placed on the holding surface of the chuck table 8, the valve is opened in a state where the suction source connected to the flow path provided inside the frame 10 of the chuck table 8 and the table base 14 via the valve is operated.

[0064] Next, the chuck table 8 and the grinding wheel 56 are moved to a prescribed position. Specifically, the X-axis direction moving mechanism (not shown) and the Z-axis direction moving mechanism 34 are operated so that the chuck table 8 and the grinding wheel 56 are apart in the X-axis direction and the lower surfaces of the plurality of grinding tools 60 are lower than the upper surface of the workpiece held by suction by the chuck table 8 and higher than the lower surface of the workpiece.

[0065] Next, the grinding wheel 56 is rotated. Specifically, the motor 52 is operated to rotate the spindle 50. Next, the chuck table 8 and the grinding wheel 56 are relatively moved in the X-axis direction to grind the workpiece. Specifically, the X-axis direction moving mechanism (not shown) is operated in such a manner that the outer side surface of the workpiece held by the chuck table 8 is brought into contact with the side surfaces of the plurality of grinding tools 60.

[0066] Thus, the end portion having a prescribed thickness on the upper surface side of the workpiece is ground by the outer side surfaces of the plurality of grinding tools 60. In addition, the entire upper surface side of the workpiece is ground by continuing the operation of the X-axis direction moving mechanism, and the workpiece is thinned.

[0067] In this creep feed grinding, the lower surface of the protruding portion 16b of the spindle 16 is brought into contact with the housing 18 before the workpiece is ground. Thus, the frictional force generated on the lower surface side of the protruding portion 16b of the spindle 16 becomes a resistance, and the vibration generated in the chuck table 8 at the time of grinding the workpiece is suppressed.

[0068] In addition, the configuration and the method of the above-described embodiment and the like can be appropriately changed and implemented as long as the purpose of the present application is not deviated. For example, one end of each of the plurality of communication paths 18c opened in the convex portion 18b of the housing 18 can be connected to a suction source such as an ejector via a pipe (not shown) and a valve (not shown).

[0069] The suction source is, for example, operated at the time of bringing the spindle 16 into contact with the housing 18 (contact step S21 shown in the drawing). Figure 3 In this case, the fluid in the gap between the spindle 16 and the housing 18 can be quickly discharged. Thus, the time required when the workpiece is ground by the creep feed grinding can be shortened.

[0070] Alternatively, the suction source can be operated at the time of grinding the workpiece by the creep feed grinding (grinding step S22 shown in the drawing). Figure 3 In this case, the creep feed grinding is performed in a state where the spindle 16 is sucked by the housing 18. Thus, the vibration generated in the chuck table 8 at the time of grinding the workpiece can be further suppressed.

[0071] In addition, the suction source can be operated in both the contact step S21 and the grinding step S22. Figure 3 In this case, the creep feed grinding is performed in a state where the spindle 16 is sucked by the housing 18. Thus, the vibration generated in the chuck table 8 at the time of grinding the workpiece can be further suppressed.

Claims

1. A grinding method, comprising grinding a workpiece using a grinding apparatus. This grinding device has the following features: A chuck table having a holding surface for holding the workpiece; A workbench base, on which the chuck workbench is mounted; The first spindle has a main body and a protrusion. The main body hangs down from the center of the lower part of the worktable base, and the protrusion protrudes outward from the side of the main body. A housing surrounding the side of the main body, and having a connecting passage inside the housing that opens at a position opposite to the lower surface of the protrusion; A fluid source supplies fluid to the connecting path; The second spindle has a lower end on which a grinding wheel with a plurality of grinding tools for grinding the workpiece is mounted. A vertical movement mechanism that causes the chuck table and the grinding wheel to move relative to each other in the vertical direction; A horizontal movement mechanism that causes the chuck table and the grinding wheel to move relative to each other in a horizontal direction perpendicular to the vertical direction. Its features are, The grinding method comprises the following steps: The selection step involves choosing whether to use plunge grinding or creep grinding to grind the workpiece. In plunge grinding, the chuck table and the grinding wheel are rotated with the chuck table positioned below the grinding wheel. While rotating the chuck table and the grinding wheel, the chuck table and the grinding wheel move relative to each other in the vertical direction to grind the workpiece. In creep grinding, the grinding wheel is rotated with the chuck table and the grinding wheel moved away in the horizontal direction and the lower surfaces of the multiple grinding tools positioned lower than the upper surface of the workpiece but higher than the lower surface of the workpiece. While rotating the grinding wheel, the chuck table and the grinding wheel move relative to each other in the horizontal direction to grind the workpiece. In the separation step, if the plunge grinding method has been selected through the selection step, fluid is supplied from the fluid supply source to the communication path to separate the lower surface of the protrusion from the housing; and In the contact step, if the creeping feed grinding is selected through the selection step, fluid is not supplied from the fluid supply source to the communication path, so that the lower surface of the protrusion contacts the housing.

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