JP6075995B2 - Grinding wheel wear amount detection method - Google Patents

Description

  The present invention relates to a method for detecting a consumption amount of a grinding wheel in a grinding apparatus that performs grinding by bringing a grinding wheel into contact with a plate-like workpiece held on a holding table and applying a load.

  A grinding apparatus for grinding a plate-like workpiece such as a semiconductor wafer is configured to hold the plate-like workpiece in a holding table, and lower the grinding means while rotating the grinding wheel to press the grinding stone against the plate-like workpiece. (For example, refer to Patent Document 1). In addition, since the grinding wheel is consumed by grinding, every time a plate-like workpiece is ground, the amount of consumption of the grinding wheel is calculated based on the lowest position in the vertical direction of the grinding means.

JP 2009-158768 A

  However, if the grinding means is ground and fed downward and the plate-like workpiece is pressed, the holding table that holds the plate-like workpiece is pushed down, and the grinding means is also lowered accordingly. Therefore, the pressing amount of the holding table is added to the consumption amount of the grinding wheel determined from the position of the grinding means, and the grinding apparatus recognizes that the grinding wheel has been consumed more than the actual consumption amount.

  The present invention has been considered in view of such problems, and in a grinding apparatus that performs grinding by pressing a grinding wheel against a plate-like work held on a holding table, the grinding wheel is pressed even if the holding table is pushed down during grinding. It is an object of the present invention to make it possible to accurately recognize the amount of consumption.

The present invention relates to a grinding wheel wear amount detection method for detecting a wear amount of a grinding wheel used in a grinding apparatus for grinding a plate workpiece, the grinding device including a holding table for holding a plate workpiece, and a holding table. Grinding means mounted with a grinding wheel for grinding the held plate-like workpiece, grinding feed means for moving the grinding means toward and away from the holding table, and a first height for measuring the upper surface height of the holding table A gauge, a second height gauge for measuring the upper surface height of the plate-like workpiece held by the holding table, and a load detection means for detecting a load that the holding table receives from the grinding means during grinding of the plate-like workpiece; At least when the holding table is not subjected to a grinding load, the first height gauge is set as the first value, and the grinding work is applied to the plate-like workpiece held by the holding table by the grinding feed means. The by feeding ground to the first value of the height gauge during grinding and end the second value, the first stored in the storage unit the difference between the first and second values as sinking of the holding table The difference between the value of the first height gauge and the value of the second height gauge at the time when the plate-like workpiece held by the holding table is ground to a desired thickness by the grinding means and the grinding is finished is The thickness of the plate-shaped workpiece before grinding is defined as the thickness of the plate-shaped workpiece, and the difference between the value of the first height gauge and the value of the second height gauge before the plate-shaped workpiece held by the holding table is ground. The difference between the thickness of the plate-like workpiece after grinding and the thickness of the plate-like workpiece before grinding is stored in the second storage unit as the amount of grinding of the plate-like workpiece, and the grinding wheel mounted on the grinding means the position of the grinding means when the tip is in contact with the upper surface of the grinding prior plate workpiece held by the holding table First and grinding feed position recognized by weight detecting means detects a load from the grinding means, the position of the grinding means during grinding completed the second grinding feed position, a first grinding feed position The difference from the second grinding feed position is stored in the third storage unit as the movement amount of the grinding means,
The consumption amount of the grinding wheel is detected from the amount of consumption of the grinding wheel = the value of the third storage unit−the value of the second storage unit−the value of the first storage unit.

  The present invention calculates the wear amount of the grinding wheel accurately because the wear amount of the grinding wheel is determined in consideration of not only the movement amount of the grinding means and the grinding amount of the plate workpiece but also the sinking amount of the holding table due to the grinding load. can do.

It is sectional drawing which shows the structure of a grinding device schematically. It is a front view which shows the positional relationship of a holding | maintenance table, a plate-shaped workpiece | work, and a grinding means at the time of grinding completion before grinding. It is a graph which shows the relationship between the grinding feed position of a grinding means, the amount of sinking of a holding table, and the thickness of a plate-shaped workpiece.

  A grinding apparatus 1 shown in FIG. 1 includes a holding table 2 that holds a plate-like workpiece W to be ground, and a grinding means 3 that is equipped with a grinding wheel 34 that grinds the plate-like workpiece W held on the holding table 2. A grinding feed means 4 for moving the grinding means 3 toward and away from the holding table 2, a first height gauge 5 for measuring the upper surface height of the holding table 2, and a plate-like workpiece W held by the holding table 2. And a second height gauge 6 for measuring the height of the upper surface.

  The holding table 2 includes a holding portion 20 formed of a porous member, and the surface side of the holding portion 20 is a holding surface 20a on which the plate-like workpiece W is placed. The holding unit 20 is connected to a suction source 21 and can suck and hold a workpiece. The holding table 2 is supported by an adjustment shaft 22 for adjusting the inclination of the holding table 2 and a fixed shaft 23 for fixing and supporting the holding table 2, and the holding table 2 is adjusted by adjusting the adjustment shaft 22. The tilt can be adjusted. Further, the holding table 2 is provided with a load detecting means 24 for detecting a pressing load during grinding. The load detecting means 24 may be provided in the grinding means 3.

  The grinding means 3 is mounted on the rotary shaft 30 having a vertical axis, a housing 31 that rotatably supports the rotary shaft 30, a wheel mount 32 formed at the lower end of the rotary shaft 30, and the wheel mount 32. A plurality of grinding wheels 34 are fixed to the lower surface of the grinding wheel 33 in an annular shape. A motor is provided inside the housing 31, and the grinding wheel 33 is also rotated by the rotation of the rotating shaft 30 driven by the motor.

  The grinding feed means 4 is in sliding contact with the guide rail 41, a ball screw 40 having a vertical axis, a guide rail 41 disposed in parallel to the ball screw 40, a motor 42 connected to one end of the ball screw 40, and the guide rail 41. An internal nut structure is composed of an elevating part 43 that is screwed onto the ball screw 40, and a linear scale 44 that is arranged in parallel with the ball screw 40. In the lifting / lowering unit 43, an instruction unit 43 a indicating the scale of the linear scale 44 is formed.

  The motor 42 constituting the grinding feed means 4 is connected to the control means 7, and the operation of the grinding feed means 4 is controlled by the control means 7. The control means 7 includes a CPU, a first storage unit 71, a second storage unit 72, and a third storage unit 73. Further, the control means 7 can read the measured values of the first gauge 5 and the second gauge 6.

  In the grinding apparatus 1 configured as described above, the holding work 2 is sucked and held by the holding table 2 and the holding table 2 is rotated. Then, while the grinding wheel 33 is rotating, under the control of the control means 7, the grinding feed means 4 lowers the grinding means 3 and brings the rotating grinding wheel 34 into contact with the upper surface W 1 of the plate-like workpiece W. Grind. And if the plate-shaped workpiece | work W is formed in desired thickness, the grinding means 3 will be raised and grinding will be complete | finished.

  As shown in FIG. 2, the height of the holding surface 20a of the holding table 2 when the holding table 2 is not subjected to a grinding load is measured by the first height gauge 5, and the value is defined as Z1s. Let Z1s be the first value. On the other hand, the grinding means 3 is ground and fed by the grinding feed means 4 to the plate-like workpiece W held by the holding table 2, and the height of the holding surface 20a when the holding table 2 receives a grinding load at the end of the grinding is set to the first level. Measured with a height gauge 5 of 1 and the value is Z1e. This Z1e is set as the second value. The difference (Z1s−Z1e) between the first value and the second value is the amount of sinking of the holding table 2 from the start of grinding to the end of grinding, and this value is stored in the first storage unit 71. Let

  Further, the height Z1e of the holding surface 20a when the plate-like workpiece W held by the holding table 2 is ground to a desired thickness by the grinding means 3 and the grinding is finished, and measured by the second gauge 6 at that time. The difference (Z1e−Z2e) from the height Z2e of the surface W1 of the plate-like workpiece W thus obtained is the thickness of the plate-like workpiece W after grinding.

  Further, the height value Z1s of the holding surface 20a before the plate-like workpiece W held by the holding table 2 is ground by the first height gauge 5 and the second height gauge 6 at that time are measured. The measured difference (Z1s−Z2s) from the height Z2s of the surface W1 of the plate-like workpiece W is the thickness of the plate-like workpiece W before grinding.

  And the difference {(Z1s-Z2s)-(Z1e-Z2e)} between the thickness of the plate-like workpiece W after grinding and the thickness of the plate-like workpiece W before grinding is the amount by which the plate-like workpiece W is ground. The value obtained by this calculation is stored in the second storage unit 72 as the grinding amount of the plate-like workpiece W.

  The position of the grinding means 3 when the tip (lower surface) of the grinding wheel 34 contacts the upper surface W1 of the plate-like workpiece W before grinding held by the holding table 2, that is, from the holding surface 20a of the holding table 2 to the plate-like workpiece W. The position added by the thickness is read by the linear scale 44 shown in FIG. 1, and the position is set as the first grinding feed position Zs. The fact that the grinding wheel 34 is in contact with the upper surface W1 of the plate-like workpiece W can be recognized by the fact that the load detection means 24 shown in FIG.

  Further, the position of the grinding means 3 at the end of grinding is read by the linear scale 44, and the position is set as the second grinding feed position Ze. Then, the difference between the first grinding feed position Zs and the second grinding feed position Ze is stored in the third storage unit 73 as the movement amount (Zs−Ze) of the grinding means 3.

  As described above, the first storage unit 71 stores the sinking amount (Z1s-Z1e) of the holding table 2 from the start of grinding to the end of grinding, and the second storage unit 72 stores the plate-like workpiece. The grinding amount of W {(Z1s−Z2s) − (Z1e−Z2e)} is stored, and the movement amount (Zs−Ze) of the grinding means 3 is stored in the third storage unit 73. The amount of movement of the grinding means 3 stored in the third storage unit 73 includes the amount of sinking of the holding table 2 stored in the first storage unit 71 and the plate shape stored in the second storage unit 72. Since this is the sum of the grinding amount of the workpiece W and the consumption amount of the grinding wheel 34 during grinding, the consumption amount of the grinding wheel 34 can be obtained by the following equation (1).

  Grinding wheel consumption amount = value of third storage unit−value of second storage unit−value of first storage unit (1)

  Such calculation is performed by a CPU provided in the control means 7. Moreover, the relationship among the value of the 3rd memory | storage part 73, the value of the 2nd memory | storage part 72, and the value of the 1st memory | storage part 71 becomes like the graph shown in FIG.

  As described above, the amount of wear of the grinding wheel 34 is determined in consideration of not only the amount of movement of the grinding means 3 and the amount of grinding of the plate workpiece W but also the amount of sinking of the holding table 2 due to the grinding load. The amount can be calculated accurately.

1: Grinding device 2: Holding table 20: Holding portion 20a: Holding surface 21: Suction source 22: Adjustment shaft 23: Fixed shaft 24: Load detecting means 3: Grinding means 30: Rotating shaft 31: Housing 32: Wheel mount 33: Grinding wheel 34: Grinding wheel 4: Grinding feed means 40: Ball screw 41: Guide rail 42: Motor 43: Lifting part 44: Linear scale 5: First height gauge 6: Second height gauge 7: Control means 71 : First storage unit 72: Second storage unit 73: Third storage unit

Claims (1)

A grinding wheel wear amount detecting method for detecting a wear amount of a grinding wheel used in a grinding apparatus for grinding a plate-like workpiece,
The grinding apparatus
A holding table for holding a plate-like workpiece, a grinding means on which a grinding wheel for grinding the plate-like workpiece held on the holding table is mounted, and a grinding feed means for causing the grinding means to approach and separate from the holding table A first height gauge for measuring the upper surface height of the holding table, a second height gauge for measuring the upper surface height of the plate-like workpiece held by the holding table, and when grinding the plate-like workpiece Load detecting means for detecting the load received by the holding table from the grinding means, at least,
The value of the first height gauge when the holding table is not subjected to a grinding load is set as a first value, and the grinding means is ground by the grinding feed means with respect to the plate-like workpiece held by the holding table. The first height gauge at the end of the grinding is set as the second value, and the difference between the first value and the second value is set as the sinking amount of the holding table. Remember
Grinding the difference between the value of the first height gauge and the value of the second height gauge when the plate work held by the holding table is ground to a desired thickness by the grinding means and the grinding is finished. The thickness of the later plate-like workpiece is used, and the difference between the value of the first height gauge and the value of the second height gauge before the plate-like workpiece held by the holding table is ground is determined as the thickness before grinding. The thickness of the plate-like workpiece, the difference between the thickness of the plate-like workpiece after grinding and the thickness of the plate-like workpiece before grinding is stored in the second storage unit as the amount of the plate-like workpiece ground,
The load detecting means detects the load from the grinding means when the tip of the grinding wheel attached to the grinding means contacts the upper surface of the plate-like workpiece before grinding held by the holding table. Is recognized as the first grinding feed position, the position of the grinding means at the end of the grinding is set as the second grinding feed position, and the difference between the first grinding feed position and the second grinding feed position is determined. The movement amount of the grinding means is stored in the third storage unit,
Grinding wheel wear amount detection method for detecting the wear amount of the grinding wheel from the value of the third storage unit−the value of the second storage unit−the value of the first storage unit.

Images