JP5719628B2 - Spindle unit - Google Patents

Description

  The present invention relates to a spindle unit having a rotating spindle.

  Wafers that are formed on the front surface by dividing devices such as IC and LSI by dividing lines are ground on the back surface by a grinding device to a predetermined thickness, and then each device is cut by a cutting device, laser processing device, etc. And is used for various electronic devices.

  A grinding apparatus used for backside grinding of a wafer includes a chuck table that holds a wafer and a grinding unit that grinds the wafer held on the chuck table. The grinding means includes a spindle unit having a spindle, a housing including a bearing that rotatably supports the spindle, a drive unit that rotationally drives the spindle, and a tool mount for mounting a grinding tool. The wafer can be processed to a desired thickness by performing grinding by bringing a rotating grinding tool into contact with the back surface of the wafer held on the chuck table (see, for example, Patent Document 1).

JP 2006-303051 A

  However, if the rotation speed of the spindle matches the resonance point of the spindle unit, the spindle vibrates and high-precision machining cannot be performed. Therefore, the rotation speed of the spindle is set so as to avoid the resonance point of the spindle unit. Therefore, there is a problem that the rotation speed of the spindle may not be set to a desired value. Such a problem occurs not only in the grinding apparatus but also in other processing apparatuses having a spindle unit.

  The present invention has been considered in view of such problems, and an object of the present invention is to provide a spindle unit in which resonance does not occur even if the rotational speed of the spindle is set to a desired rotational speed.

The present invention includes at least a spindle, a housing in which a bearing for supporting the spindle is disposed, a drive unit mounted on one end of the spindle, and a tool mount for mounting a tool on the other end of the spindle. One end of the spindle is provided with a protruding rod that protrudes a predetermined length from the drive unit, and a single weight that can move and be fixed in the axial direction is arranged on the protruding rod. It is provided, and the position of the weight in the axial direction of the protruding rod is adjusted to release the resonance caused by the rotational speed of the spindle.

  The spindle unit according to the present invention includes a projecting rod projecting from the drive unit, and the projecting rod is provided with a weight that can be moved and fixed in the axial direction, and the spindle can be rotated by adjusting the position of the weight. The resonance caused by the number can be canceled. Therefore, when vibration is generated when the spindle is rotated at a desired number of rotations, resonance can be prevented from occurring by appropriately moving the weight in the axial direction of the protruding rod.

It is a perspective view which shows an example of a spindle unit. It is sectional drawing which shows an example of a spindle unit. It is a perspective view which shows an example of the grinding apparatus provided with the spindle unit.

  The spindle unit 1 shown in FIG. 1 is configured such that a spindle 2 is rotatably supported by a housing 3. The lower end of the spindle 2 protrudes from the housing 3, and a tool mount 7 for mounting a tool is mounted on the protruding portion. Various tools can be attached to the tool mount 7 and fixed with screws 70. In the example of FIG. 1, a grinding wheel 100 composed of a base 100 a and a plurality of grindstones 100 b fixed to the base 100 a is fixed to the tool mount 7.

  As shown in FIG. 2, the housing 3 is provided with a thrust bearing 4 for supporting the spindle 2 in the thrust direction and a radial bearing 5 for supporting the spindle 2 in the radial direction.

  A drive unit 6 that rotationally drives the spindle 2 is attached to one end (upper end in the drawing) of the spindle 2. The drive unit 6 is a motor that includes a rotor 60 connected to the spindle 2 and a stator 61 that rotates the rotor 60. The rotor 60 is provided with a protruding rod 8 that extends from the housing 3 in the axial direction. Thus, the protruding rod 8 protrudes from the drive unit 6. On the other hand, a tool mount 7 for mounting a tool is mounted on the other end (lower end in the figure) of the spindle 2.

  The spindle 2 is formed with a disc-shaped thrust plate 2a having a plane orthogonal to the axial direction. The housing 3 is formed in a substantially cylindrical shape, and the inner diameter of the housing 3 at a position where the thrust plate 2a is accommodated is increased in accordance with the outer diameter of the thrust plate 2a. In the housing 3, a plurality of spouts 40 and 41 for spouting air toward the respective planes of the thrust plate 2 a are formed in a ring shape at positions facing both planes of the thrust plate 2 a. The outlet 41 constitutes a thrust bearing 4 that supports the spindle 2 in the thrust direction.

  On the inner peripheral surface of the housing 3, that is, the surface facing the side surface of the spindle 2, there are formed a plurality of jet ports 50 for jetting air toward the axis of the spindle 2, and these jet ports 50 are jetted. A radial bearing 5 is configured to support the spindle 2 in the radial direction by air.

  The jet nozzles 40 and 41 constituting the thrust bearing 4 and the jet nozzle 50 constituting the radial bearing 5 communicate with the air supply port 31 via the air flow path 30 formed inside the housing 3 to supply air. The air introduced from the port 31 is ejected from the ejection ports 40, 41, and 50 through the air flow path 30, thereby supporting the spindle 2 so as to be rotatable in a non-contact state. Further, the air ejected from the ejection ports 40, 41, 50 is exhausted from the exhaust ports 320, 321 provided at both ends of the housing 3.

  The protruding rod 8 is provided with a weight 9 that can move in the axial direction. The weight 9 is formed in a ring shape, and a protruding rod 8 is inserted into the inner peripheral side of the weight 9 so that the weight 9 can slide with respect to the protruding rod 8. A plurality of screws 90 whose tips are directed to the axial center of the projecting rod 8 are inserted from the side surface of the weight 9. When the screws 90 are loosened, the arrows A and FIGS. The weight 9 can be moved in the direction B, and when the screw 90 is tightened, the weight 9 can be fixed to the protruding rod 8 at that position. The protruding amount of the protruding rod 8 from the housing 3 is determined in consideration of the movable range of the weight 9.

  As shown in FIG. 2, the spindle unit 1 is configured to rotate the tool mounted on the tool mount 7 by being driven by the drive unit 6 and rotating the spindle 2.

  When the spindle 2 is rotated at a desired rotational speed, the spindle 2 vibrates when the rotational speed matches the resonance point of the spindle unit 1. When resonance occurs in this manner, for example, when the tool mounted on the tool mount 7 is the grinding wheel 100, the grinding wheel vibrates and high-precision grinding cannot be performed. Therefore, in such a case, the weight 9 is slid along the protruding rod 8 and moved, and the screw 90 is tightened to fix the weight 9. Then, resonance does not occur even if the spindle 2 is rotated at the desired number of rotations, and the resonance can be canceled.

  The spindle unit 1 shown in FIGS. 1 and 2 is mounted on a grinding apparatus 10 shown in FIG. 3, for example. The grinding apparatus 10 includes a plurality of chuck tables 11 that can hold and rotate wafers, a first grinding unit 12 that performs rough grinding on the wafers held on the chuck tables 11, and a first grinding unit. The second grinding means 13 for finish grinding the surface to be ground of the wafer roughly ground by 12, the first grinding feed means 14 for grinding and feeding the first grinding means 12 in the vertical direction, and the second grinding means And second grinding feed means 15 for grinding and feeding 13 in the vertical direction.

  The grinding apparatus 10 includes a first cassette 16a that stores a wafer before grinding and a second cassette 16b that stores a ground wafer. In the vicinity of the first cassette 16a and the second cassette 16b, loading / unloading means having a function of unloading the wafer before grinding from the first cassette 16a and loading the ground wafer into the second cassette 16b. 17 is disposed.

  The carry-in / out means 17 has a configuration in which a holding portion 171 for holding the wafer is provided at the tip of the bendable arm portion 170, and the position of the wafer before processing is aligned with the movable range of the holding portion 171. Positioning means 18 and cleaning means 19 for cleaning the ground wafer are provided.

  A first transport unit 20 a is disposed in the vicinity of the alignment unit 18, and a second transport unit 20 b is disposed in the vicinity of the cleaning unit 19. The first transport unit 20 a has a function of transporting the unground wafer placed on the alignment unit 18 to any one of the chuck tables 11, and the second transport unit 20 b includes any one of the chuck tables 11. The machine has a function of transporting the ground wafer held by the cleaning means 19. The plurality of chuck tables 11 are supported by the turntable 21 so as to be capable of rotating and revolving, and any one of the chuck tables 11 is in the vicinity of the first conveying means 20a and the second conveying means 20b by the rotation of the turntable 21. It is configured to be positioned.

  The first grinding means 12 and the second grinding means 13 include the spindle unit 1 shown in FIGS. 1 and 2. A grinding wheel 101 for rough grinding is mounted on the spindle 2 constituting the first grinding means 12 via a tool mount 7. On the other hand, a grinding wheel 102 for finish grinding is attached to the spindle unit 2 constituting the second grinding means 13 via a tool mount 7.

  The grinding wheel 101 is configured by a plurality of grinding wheels 101b for rough grinding being fixed to a base 101a, and the grinding wheel 101 is also rotated by being driven by the drive unit 6 and rotating the spindle 2. . Further, the grinding wheel 102 is configured by fixing a plurality of grinding wheels 102b for finish grinding to the base 102a, and the grinding wheel 102 is rotated by being driven by the driving unit 6 and rotating the spindle 2. ing.

  The first grinding feed means 14 includes a ball screw 140 having a vertical axis, a pair of guide rails 141 disposed in parallel to the ball screw 140, and a pulse motor 142 connected to the ball screw 140 and rotating the ball screw 140. And an elevating part 143 whose inner nut is screwed to the ball screw 140 and whose side part is in sliding contact with the guide rail 141. The elevating part 143 is driven by the pulse motor 142 and rotates as the ball screw 140 rotates. The guide rail 141 is guided to move up and down. The elevating part 143 supports the first grinding means 12, and the first grinding means 12 is also raised and lowered by the elevating part 143.

  The second grinding feed means 15 includes a ball screw 150 having a vertical axis, a pair of guide rails 151 arranged in parallel to the ball screw 150, and a pulse motor 152 that is connected to the ball screw 150 and rotates the ball screw 150. And an elevating part 153 whose inner nut is screwed into the ball screw 150 and whose side part is in sliding contact with the guide rail 151. The elevating part 153 is driven by the pulse motor 152 and rotates as the ball screw 150 rotates. It is configured to move up and down while being guided by the guide rail 151. The elevating part 153 supports the second grinding means 13, and the second grinding means 13 is also raised and lowered by raising and lowering the elevating part 153.

  Next, the case where the surface of the wafer W accommodated in the first cassette 16a is ground using the grinding apparatus 10 shown in FIG. 3 will be described. First, the wafer W accommodated in the first cassette 16 a is taken out by the carry-in / out means 17 and transferred to the alignment means 18. Then, after the wafer W is aligned at a certain position by the alignment means 18, the wafer W is held on the chuck table 11 and the surface to be ground is exposed.

  Next, the turntable 21 rotates counterclockwise by a predetermined angle (120 degrees in the illustrated example), whereby the wafer W moves below the first grinding means 12. Then, the wafer W rotates with the rotation of the chuck table 11, the grinding wheel 101 rotates with the rotation of the spindle 2, and the first grinding unit 12 feeds the ground downward by the first grinding feed unit 14. And descend. Then, the rotating grinding wheel 101b contacts the surface to be ground of the wafer W, and the surface to be ground is roughly ground.

  After the rough grinding is finished, the turntable 21 rotates by a predetermined angle, so that the roughly ground wafer W moves below the second grinding means 13. Then, the wafer W rotates with the rotation of the chuck table 11, the grinding wheel 102 rotates with the rotation of the spindle 2, and the second grinding unit 13 feeds the second grinding unit 13 downwardly by the second grinding feed unit 15. And descend. Then, the rotating grinding wheel 102b contacts the surface to be ground of the wafer W, and the surface to be ground is finish-ground.

  After the finish grinding is finished, the turntable 21 rotates by a predetermined angle, so that the chuck table 11 holding the ground wafer W moves to the vicinity of the second transfer means 20b. And the wafer W is hold | maintained by the 2nd conveyance means 20b, and is conveyed by the washing | cleaning means 19, and the wafer W is wash | cleaned and the grinding dust adhering to the to-be-ground surface is removed.

  The cleaned wafer W is held by the loading / unloading means 17 and accommodated in the second cassette 16b. A series of steps as described above are performed on all the wafers accommodated in the first cassette 16a.

  In the rough grinding by the first grinding means 12 and the finish grinding by the second grinding means 13, if the rotation speed of the spindle 2 coincides with the resonance point of each spindle unit 1, the spindle 2 vibrates, so that the grinding accuracy decreases. It will be. Therefore, in each grinding means, the weight 9 is moved and fixed in the vertical direction to release the resonance caused by the rotational speed of the spindle 2 and prevent the spindle 2 from vibrating.

  The spindle unit has individuality, and even the spindle units having the same structure have different resonance points. Therefore, the position of the weight 9 is adjusted for each spindle unit to prevent vibration. By preventing the occurrence of resonance in this way, it is possible to perform highly accurate grinding, and it is possible to improve the wafer thickness accuracy, surface roughness, and the like.

  In the above-described embodiment, the grinding apparatus is described as an example of the apparatus on which the spindle unit 1 is mounted. However, the apparatus on which the spindle unit 1 is mounted includes other apparatuses such as a cutting apparatus, for example. It can be applied to other devices.

1: Spindle unit 2: Spindle 2a: Thrust plate 3: Housing 30: Air flow path 31: Air supply port 320, 321: Discharge port 4: Thrust bearing 40, 41: Jet port 5: Radial bearing 50: Jet port 6: Drive unit 60: Rotor 61: Stator 7: Tool mount 70: Screw 8: Protruding rod 9: Weight 90: Screw 10: Grinding device 11: Chuck table 12: First grinding means 13: Second grinding means 14: First One grinding feed means 140: Ball screw 141: Guide rail 142: Pulse motor 143: Lifting part 15: Second grinding feed means 150: Ball screw 151: Guide rail 152: Pulse motor 153: Lifting part 16a: First cassette 16a
16b: second cassette 16b
17: carrying-in / out means 170: arm part 171: holding part 18: positioning means 19: cleaning means 20a: first conveying means 20b: second conveying means 21: turntable 100: grinding wheel 100a: base 100b: Grinding wheel 101: Grinding wheel 101a: Base 101b: Grinding wheel 102: Grinding wheel 102a: Base 102b: Grinding wheel

Claims (1)

A spindle, a housing in which a bearing for supporting the spindle is disposed, a drive unit mounted on one end of the spindle, and a tool mount for mounting a tool on the other end of the spindle; A configured spindle unit,
One end of the spindle includes a projecting rod projecting from the drive unit, and the projecting rod is provided with a single weight movable and fixed in the axial direction.
A spindle unit that adjusts the position of the weight in the axial direction of the projecting rod to release resonance caused by the rotational speed of the spindle.

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