JP2019005865A - Workpiece processing method - Google Patents

Abstract

To provide a processing method capable of locally executing flattening work on a workpiece.SOLUTION: Provided is a processing method for processing a workpiece 11 with a processing device comprising a chuck table 10 having a holding surface 11b for holding the workpiece 11, processing means having an annular ring-shaped processing tool 54 installed on one end of a spindle 52, and moving means for moving the processing means in a direction orthogonal to the direction of the spindle rotary shaft 52a and in a height direction toward and away from the chuck table 10. The method includes a holding step of holding the workpiece 11 with the chuck table 10, a detection step of detecting an area on the workpiece 11 that requires processing after executing the holding step, and a processing step of applying processing to the area of the workpiece held by the chuck table 10 detected by the detection step after executing the detection step, while rotating the processing tool 54.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a workpiece processing method for grinding or polishing a workpiece held on a chuck table.

  When grinding a wafer such as a semiconductor wafer, the wafer is sucked and held by a chuck table, and the wafer is rotated by rotating the chuck table. A grinding apparatus that performs in-feed grinding that rotates and performs grinding is generally used.

  When performing backside grinding of a wafer with multiple devices formed on the surface using such a grinding machine, a protective tape should be applied to the surface of the wafer, and the surface of the wafer should be in direct contact with the holding surface of the chuck table. Is preventing.

  By the way, in the in-feed grinding, the work amount per unit time differs due to the difference in peripheral speed between the vicinity of the rotation center of the wafer and the outer peripheral part, and the grinding amount of the outer peripheral part is larger than that of the inner peripheral part. The shape is ground into a gentle chevron shape with a high central portion.

  In order to cope with this problem, a grinding apparatus capable of detecting the flatness of a wafer after grinding and changing the inclination of the chuck table in accordance with the detected flatness is proposed in Japanese Patent Application Laid-Open No. 2008-264913.

  According to this grinding apparatus, desired flatness can be realized in grinding of the second and subsequent wafers by adjusting the tilt of the chuck table based on the processing result of the wafer ground by the first sheet.

JP 2008-264913 A

  However, there is a problem that it is very inefficient and productivity is lowered when a first wafer is ground and the wafer after grinding is again put into the grinding apparatus to flatten and a series of grinding operations are performed.

  This invention is made | formed in view of such a point, The place made into the objective is to provide the processing method which can implement flat processing locally with respect to a to-be-processed object.

  According to the present invention, a chuck table having a holding surface for holding a workpiece and a table rotation axis passing through the center of the holding surface, a spindle having a spindle rotation axis orthogonal to the table rotation axis, and one end of the spindle A processing means having an annular processing tool mounted on the outer periphery with a grinding wheel or polishing member formed on the outer periphery, the spindle rotation axis direction, a direction parallel to the holding surface and perpendicular to the spindle rotation axis direction, A machining method for machining a workpiece with a machining apparatus comprising: a moving means for moving the machining means in a height direction perpendicular to the spindle rotation axis direction and approaching and moving away from the chuck table. A holding step for holding the workpiece on the chuck table, and detecting a region on the workpiece that needs to be processed after the holding step is performed. A detection step, and a processing step of performing processing while rotating the processing tool with respect to the region detected in the detection step of the workpiece held by the chuck table after performing the detection step. Provided is a method of processing a workpiece characterized in that it is provided.

  According to the present invention, the detection step for detecting the region that needs to be processed on the workpiece is performed while holding the workpiece on the chuck table, so that the region detected in the detection step is processed in the same processing apparatus. Thus, local flat processing is possible.

It is a perspective view of the grinding device concerning the present invention carrying. FIG. 2A is a front view of the wafer before performing grinding or polishing, and FIG. 2B is a front view of the wafer after performing grinding or polishing. It is sectional drawing which shows a holding | maintenance step. It is sectional drawing which shows a detection step. It is sectional drawing which shows a grinding process step.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, there is shown a perspective view of a grinding apparatus 2 suitable for carrying out the grinding method of the embodiment of the present invention. A pair of guide rails 6 extending in the X-axis direction are fixed on the base 4 of the grinding apparatus 2.

  A table base 8 is mounted on the guide rail 6, and a nut portion attached to the table base 8 is screwed into the ball screw 22. A pulse motor 24 is connected to one end of the ball screw 22, and the ball screw 22 and the pulse motor 24 constitute an X-axis moving mechanism 26. When the ball screw 22 is rotated by driving the pulse motor 24 of the X-axis moving mechanism 26, the table base 8 is guided by the guide rail 6 and moves in the X-axis direction.

  A chuck table 10 is rotatably mounted on the table base 8, and the chuck table 10 is rotated counterclockwise or clockwise by a motor accommodated in the table base 8.

  As shown in FIG. 3, the chuck table 10 includes a suction holding portion 12 made of porous ceramics and the like, and a metal frame 14 surrounding the suction holding portion 12. The suction holding portion 12 is a frame. A suction source 16 is selectively connected to the suction source 20 via a suction path 16 and an electromagnetic switching valve 18 formed in the body 14.

  As shown in FIGS. 4 and 5, the suction holding portion 12 of the chuck table 10 has a holding surface 12a for holding the workpiece, and the chuck table 10 passes through the center of the holding surface 12a to the holding surface 12a. It has a vertical table rotation shaft 10a.

  A support member 29 is erected on the table base 8, and a height detection sensor 28 that detects the upper surface height of the wafer 11 held on the chuck table 10 is swingably attached to the support member 29. . As the height detection sensor 28, a known laser type or electrostatic capacitance type sensor can be used.

  A pair of guide rails 30 extending in the Y-axis direction orthogonal to the X-axis are fixed on the base 4. A nut portion is fixed to the horizontal portion 32a of the Y-axis moving member 32, and this nut portion is screwed into a ball screw 34 that extends in the Y-axis direction.

  A pulse motor 36 is connected to one end of the ball screw 34, and the ball screw 34 and the pulse motor 36 constitute a Y-axis moving mechanism 38. When the pulse motor 36 of the Y-axis moving mechanism 38 is driven, the ball screw 34 rotates and the Y-axis moving member 32 is guided by the pair of guide rails 30 and moves in the Y-axis direction.

  The Y-axis moving member 32 has a vertical portion 32b orthogonal to the horizontal portion 32a. A pair of guide rails 40 are fixed to the vertical portion 32 b of the Y-axis moving member 32. A nut portion is fixed to the spindle housing 50 of the grinding unit 48, and this nut portion is screwed into a ball screw 42 extending in the Z-axis direction.

  A pulse motor 44 is connected to one end of the ball screw 42, and the ball screw 42 and the pulse motor 44 constitute a Z-axis moving mechanism. When the pulse motor 44 of the Z-axis moving mechanism 46 is driven, the ball screw 42 rotates and the grinding unit 48 is moved in the vertical direction (Z-axis direction).

  A spindle 52 is rotatably accommodated in the spindle housing 50 of the grinding unit 48. As best shown in FIG. 5, the rotation shaft 52 a of the spindle 52 is orthogonal to the table rotation shaft 10 a of the chuck table 10 and is disposed in parallel to the Y axis. An annular grinding wheel 54 is attached to one end of the spindle 52.

  Next, a workpiece to be processed by the processing method of the present invention will be described with reference to FIG. FIG. 2A shows a front view of a wafer 11 such as a silicon wafer before grinding, and the front surface 11a and the back surface 11b of the wafer 11 are flat surfaces. When the wafer 11 is a semiconductor wafer, a plurality of devices are formed on the surface 11a of the wafer 11 so as to be partitioned into a plurality of scheduled division lines (streets) orthogonal to each other.

  When grinding such a back surface 11b of the wafer 11, in order to protect a device formed on the front surface 11a of the wafer 11, a protective tape is attached to the front surface 11a of the wafer 11, and a normal infeed is performed. The protective tape side is sucked and held by the chuck table of the grinding device, and the back surface 11b of the wafer 11 is ground.

  In normal in-feed grinding, the rotation speed on the outer peripheral side of the wafer 11 is faster than that on the inner peripheral side, so the amount of grinding on the outer peripheral side of the wafer 11 is larger than that on the inner peripheral side. As shown to (B), the wafer 11 is easy to be ground by the convex shape in which the inner peripheral side is slightly higher than the outer peripheral side.

  When grinding the back surface 11b of the wafer 11 with the grinding apparatus 2 shown in FIG. 1, a protective tape is similarly applied to the front surface 11a of the wafer 11, and the protective tape side of the wafer 11 is sucked and held by the chuck table 10. To do.

  Then, as shown in FIG. 5, the chuck table 10 is rotated in the direction of arrow a at a rotational speed of, for example, 300 rpm, and the annular grinding wheel 54 is pressed against the back surface 11b of the wafer 11 while rotating at high speed in the direction of arrow b. The back surface 11b of the wafer 11 is ground by moving the annular grinding wheel 54 in the arrow Y1 direction. After completion of grinding, the height detection sensor 28 is swung to detect the height position of the back surface 11b of the wafer 11, and the flatness of the back surface 11b is detected.

  When the back surface 11b of the wafer 11 is ground by a general in-feed type grinding apparatus, and the wafer 11 has a middle convex shape as shown in FIG. 2B, the surface 11a of the wafer 11 is formed. After the protective tape 13 is adhered, the wafer 11 is put into the grinding apparatus 2 shown in FIG. 1, and the wafer 11 is sucked and held by the holding surface 12a of the chuck table 10 through the protective tape 13 as shown in FIG. The back surface 11b is exposed (holding step).

  Next, as shown in FIG. 4, the height detection sensor 28 is swung in the direction of the arrow R1, the height position of the back surface 11b of the wafer 11 is detected, and an area that requires processing for flattening the back surface 11b is formed. To detect. This detection step is preferably performed while rotating the chuck table 10 in the direction of arrow a at a low speed.

  As described above, when the height of the back surface 11b of the wafer 11 is detected by swinging the height detection sensor 28 in the direction of the arrow R1 while rotating the chuck table 10 in the direction of the arrow a at a low speed, the middle convex shape shown in FIG. In addition, it is possible to locally detect a region that needs to be processed in order to flatten the back surface 11b of the wafer 11.

  After performing the detection step, a grinding step is performed for grinding the region that requires the processing detected in the detection step. In this grinding step, as shown in FIG. 5, while rotating the chuck table 10 holding the wafer 11 in the direction of arrow a at 300 rpm, for example, an annular grinding wheel 54 that rotates at high speed in the direction of arrow b is used. The back surface 11b of the wafer 11 is ground by pressing against 11b and processing and feeding the grinding unit 48 in the direction of the arrow Y1.

  In this grinding step, if the region requiring processing is local, an annular grinding wheel 54 that rotates at high speed without rotating the chuck table 10 holding the wafer 11 is pressed against the region requiring processing to locally Alternatively, grinding may be performed.

  In the above-described embodiment, the embodiment in which the processing tool mounted on the tip of the spindle 52 is the annular grinding wheel 54 has been described. You may do it. In this case, the back surface 11b of the wafer 11 can be locally polished.

  In the above-described embodiment, an example in which a wafer such as a semiconductor wafer is ground as the workpiece has been described. However, the workpiece is not limited to the wafer, and other workpieces such as a ceramic substrate and a resin substrate may be used. The workpiece can also be locally ground or polished.

2 Grinding device 10 Chuck table 11 Wafer 12a Holding surface 13 Protective tape 28 Height detection sensor 48 Grinding unit 54 Annular grinding wheel

Claims (1)

A chuck table having a holding surface for holding a workpiece and a table rotation axis passing through the center of the holding surface, a spindle having a spindle rotation axis orthogonal to the table rotation axis, and mounted on one end of the spindle on the outer periphery A processing means having an annular processing tool on which a grinding wheel or a polishing member is formed, the spindle rotation axis direction, a direction parallel to the holding surface and perpendicular to the spindle rotation axis direction, and the spindle rotation axis direction And a moving means for moving each of the processing means in a height direction that is perpendicular to and close to and away from the chuck table, and a processing method for processing a workpiece with a processing apparatus comprising:
A holding step for holding a workpiece on the chuck table;
A detection step for detecting a region that needs to be processed on the workpiece after performing the holding step;
A processing step of performing processing while rotating the processing tool with respect to the region detected in the detection step of the workpiece held by the chuck table after performing the detection step;
A method for processing a workpiece, comprising: