JP6205231B2 - Cutting equipment - Google Patents

Description

  The present invention relates to a cutting apparatus for removing a portion of a wafer where chamfering of an edge portion is performed.

  If one side of a wafer with a chamfered outer periphery is ground, the outer periphery is formed at an acute angle, and cracks and chipping may occur starting from that portion. The chamfered portion is removed along the outer periphery. In addition, when the diameter of the wafer is reduced, the wafer is cut into a circle along the outer periphery. Cutting along the outer peripheral edge of the wafer in this way is called edge trimming.

  Edge trimming for cutting in a circle along the outer periphery of the wafer is performed by bringing a rotating cutting blade into contact with the outer periphery of the wafer and rotating a holding table holding the wafer (for example, Patent Documents 1 and 2). reference).

JP 2010-245167 A JP 2010-245254 A

  However, in edge trimming, there is a problem in that the cutting depth cannot be made uniform if uneven wear occurs in the thickness direction in the outer peripheral end of the rotating cutting blade.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a cutting apparatus capable of preventing the occurrence of cutting defects on the outer peripheral edge of the wafer due to uneven wear or the like on the outer peripheral end side of the cutting blade. And

The cutting apparatus of the present invention includes a chuck table for holding a disk-shaped wafer, a rotating means for rotating the chuck table, and a disk-shaped cutting grindstone on the outer peripheral edge of the wafer held by the rotating chuck table. A cutting means for contacting the cutting blade to remove the chamfered portion of the outer peripheral edge of the wafer, the cutting means comprising: a spindle for rotatably mounting the cutting blade; A non-feeding means for measuring the height of the outer peripheral edge of the cutting blade, comprising at least a cutting feed means for moving the chuck table in the direction of approaching and moving away from the chuck table and an indexing feed means for moving the spindle in the axial direction of the spindle. Judgment to judge the quality of the outer peripheral edge shape in the width direction of the cutting blade from the measurement result of the contact measurement unit and the non-contact measurement unit With the door, the non-contact measurement section is a laser displacement meter using a spot laser beam, the spot laser beam from the light projecting portion toward the outer peripheral edge of the cutting blade in a direction perpendicular to the axis of the spindle The height of the outer peripheral edge of the cutting blade can be measured by a light receiving unit that emits light and receives the reflected light reflected by the outer peripheral end of the cutting blade. Are measured by the non-contact measuring unit, and the height of the outer peripheral edge of the cutting blade in the width direction of the cutting blade is measured by the non-contact measuring unit. Measuring .

  According to this configuration, the outer peripheral end of the cutting blade is directly measured by the non-contact measuring unit, and the determination unit determines the quality of the outer peripheral end shape in the width direction of the cutting blade from the measurement result. It is possible to continue the cutting only when it is, and it is possible to avoid the occurrence of defective cutting at the outer peripheral edge of the wafer. Further, since the height of the outer peripheral edge of the cutting blade is measured, the distance between the outer peripheral edge of the cutting blade and the upper surface of the chuck table can be calculated. As a result, the reference position of the cutting feed means in which the outer peripheral end of the cutting blade contacts the upper surface of the chuck table can be calculated, and the cutting accuracy in the thickness direction of the wafer can be increased.

  In the cutting apparatus, the non-contact measuring unit is a laser displacement meter using a strip laser beam, and the strip laser beam is positioned parallel to the axial direction of the spindle, and the strip laser beam is positioned on the spindle. Of the cutting blade in the width direction of the cutting blade by a light receiving unit that projects light toward the outer peripheral end of the cutting blade in a direction perpendicular to the axial direction of the cutting blade and receives reflected light reflected by the outer peripheral end of the cutting blade. You may make it possible to measure the height of an outer periphery end.

  In the cutting apparatus, it is preferable that the non-contact measuring unit measures the height of the outer peripheral end of the cutting blade from the tangential direction of the cutting blade.

  According to the present invention, since the height of the outer peripheral edge of the cutting blade is measured and the quality of the outer peripheral edge shape is judged, cutting failure occurs on the outer peripheral edge of the wafer due to uneven wear or the like on the outer peripheral edge side of the cutting blade. Can be prevented.

1 is a perspective view of a cutting device according to Embodiment 1. FIG. 2A is a schematic front view of the cutting apparatus according to Embodiment 1, and FIG. 2B is a side view of a part of the configuration shown in FIG. 2A. It is a disassembled front view of the structure of a part of cutting means. FIG. 4A is a schematic front view showing a state in which a cutting surface is measured by a non-contact measuring unit, and FIG. 4B is an enlarged view of a part A in FIG. 4A. 3 is a flowchart of a wafer processing method according to the first embodiment. It is explanatory drawing of edge trimming process. 7A and 7B are explanatory diagrams of edge trimming processing when uneven wear occurs in the wafer. It is a block diagram of the non-contact measurement part which concerns on Embodiment 2, FIG. 8A is a schematic side view, and FIG. 8B is a schematic front view. It is explanatory drawing of the non-contact measurement part which concerns on a modification. It is explanatory drawing of the non-contact measurement part which concerns on another modification.

(Embodiment 1)
Hereinafter, the cutting apparatus according to Embodiment 1 will be described with reference to the accompanying drawings. 1 is a perspective view of a cutting apparatus according to Embodiment 1. FIG. 2A is a schematic front view of the cutting apparatus, and FIG. 2B is a side view of a part of the configuration shown in FIG. 2A. Here, although the cutting device provided with a pair of cutting blade is illustrated, it is not limited to this structure.

  As shown in FIGS. 1 and 2, the cutting apparatus 1 includes a cutting unit 3 that performs edge trimming by bringing a cutting blade 33 into contact with the outer peripheral edge of the wafer W on the chuck table 2 and cutting it. The wafer W is formed in a disk shape. Further, a chamfered portion W1 (see FIG. 6) is provided on the outer peripheral edge of the wafer W to prevent cracking and dust generation during the manufacturing process.

  As shown in FIG. 3, the cutting means 3 is attached to a pair of spindles 31 (see FIG. 1, one of which is not shown in FIG. 3) having an axis in the Y-axis direction, and the spindle 31 via a mount 32. A cutting blade 33. The mount 32 includes a flange portion 320 that supports the cutting blade 33 on the surface, and a blade insertion portion 321 into which the cutting blade 33 is inserted. The blade insertion portion 321 is formed with a male screw 321a to which a nut for fixing the cutting blade 33 is screwed.

  The cutting blade 33 is held by a base 34 in which a through hole 34a for insertion into the blade insertion portion 321 is formed at the center. The cutting blade 33 is composed of a disc-shaped cutting grindstone fixed in a state of protruding from the base 34 to the outer peripheral side, and a surface forming the outer peripheral end is formed as a grinding surface 33 a for cutting the wafer W. The cutting blade 33 is supported in close contact with the cutting blade attachment surface 320a of the flange portion 320 when the blade insertion portion 321 is inserted into the through hole 34a and a nut (not shown) is screwed onto the male screw 321a.

  Returning to FIG. 1, the cutting means 3 has a cutting feed means 4 for cutting and feeding the chuck table 2 in the X-axis direction on the base 11. Further, on the base 11, a gate-shaped column portion 12 erected so as to straddle the cutting feed means 4 is provided. The cutting means 3 includes index feeding means 5 that is provided in the column portion 12 and that indexes and feeds each cutting blade 33 in the Y-axis direction above the chuck table 2. Further, the cutting means 3 includes a cutting feed means 6 that is provided in the index feed means 5 and moves the cutting blade 33 up and down in the Z-axis direction.

  The cutting feed means 4 has a pair of guide rails 41 arranged on the upper surface of the base 11 and parallel to the X-axis direction, and a motor-driven X-axis table 42 slidably installed on the pair of guide rails 41. doing. On the X-axis table 42, the chuck table 2 is rotatably supported by a θ table (rotating means) 43. A nut portion (not shown) is formed on the back side of the X-axis table 42, and a ball screw 44 is screwed to the nut portion. A drive motor 45 is connected to one end of the ball screw 44. The ball screw 44 is rotationally driven by the drive motor 45, and the chuck table 2 is moved along the guide rail 41 in the X-axis direction.

  The chuck table 2 is provided on a θ table 43 that can rotate about the Z-axis. On the surface of the chuck table 2, a holding surface 21 for sucking and holding the wafer W by a porous ceramic material is formed. The holding surface 21 is connected to a suction source (not shown) through a flow path in the chuck table 2.

  The indexing and feeding means 5 has a pair of guide rails 51 parallel to the Y-axis direction with respect to the front surface of the column portion 12 and a pair of motor-driven Y-axis tables 52 slidably installed on the pair of guide rails 51. doing. A nut portion (not shown) is formed on the back side of each Y-axis table 52, and a ball screw 55 is screwed to the nut portion. A drive motor 57 is connected to one end of the ball screw 55. The ball screw 55 is rotationally driven by the drive motor 57, and the cutting blade 33 is moved along the guide rail 51 in the Y-axis direction.

  The cutting feed means 6 includes a pair of guide rails 61 arranged in front of each Y-axis table 52 and parallel to the Z-axis direction, and a motor-driven Z-axis table 62 slidably installed on each guide rail 61. Have. A cutting blade 33 is provided below each Z-axis table 62. Further, nut portions (not shown) are formed on the back side of each Z-axis table 62, and a ball screw 63 is screwed to these nut portions. A drive motor 64 is connected to one end of the ball screw 63. The ball screw is rotationally driven by the drive motor 64, and the pair of cutting blades 33 are moved along the guide rail 61 in the Z-axis direction.

  A dresser board 7 and a non-contact measuring unit 8 are respectively provided on the upper surface of the base 11 and sandwiching the chuck table 2 in the Y-axis direction. Even if uneven wear occurs in the Y-axis direction on the cutting surface 33a of the cutting blade 33, the dresser board 7 cuts the rotating cutting blade 33 so that the shape of the cutting surface 33a becomes parallel to the Y-axis direction. To be corrected.

  FIG. 4A is a schematic front view showing a state in which a cutting surface is measured by a non-contact measuring unit, and FIG. 4B is an enlarged view of a part A in FIG. 4A. As shown in FIGS. 4A and 4B, the non-contact measuring unit 8 includes a light projecting unit 81 and a light receiving unit 82, and is configured by a laser displacement meter using a spot laser beam. The light projecting unit 81 projects the measurement light B, which is a spot laser beam, toward the cutting surface 33a that forms the outer peripheral end of the cutting blade 33 positioned above. The light projecting direction of the measurement light B by the light projecting unit 81 is set parallel to the Z-axis direction perpendicular to the axial direction (Y-axis direction) of the spindle 31. The light receiving unit 82 receives the measurement light B reflected by the cutting surface 33a. The light receiving unit 82 includes a CCD, and measures the height (position in the Z-axis direction) of the cutting surface 33a according to the position of the measurement light B received by the CCD.

  Returning to FIG. 1, the non-contact measuring unit 8 is connected to the control unit 9 and outputs a measurement result as height position information of the cutting surface 33 a to the control unit 9. The control means 9 includes a processor that executes various processes, and a storage medium such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The control means 9 controls, for example, the driving direction and driving amount of the cutting feed means 6 according to the measurement result of the cutting surface 33a by the non-contact measuring unit 8. In the judgment part 91 of the control means 9, the quality of the cutting surface 33a in the width direction (Y-axis direction) of the cutting blade 33 is determined from the measurement result of the non-contact measuring part 8, that is, whether or not cutting can be continued after measurement. to decide.

  Next, with reference to FIG. 5, a series of flows of the wafer processing method by the cutting apparatus 1 will be described in detail. FIG. 5 is a flowchart of the wafer processing method according to the present embodiment. The following flowchart is merely an example, and can be changed as appropriate.

  FIG. 6 is an explanatory diagram of edge trimming. As shown in FIGS. 2, 5, and 6, first, edge trimming is performed (step S01). In the edge trimming process, cutting is performed so as to remove the chamfered portion W1 on the outer peripheral edge of the wafer W. In the edge trimming process, the wafer W is held on the holding surface 21 of the chuck table 2 via a conveying means (not shown). The wafer W is held so that the surface on which the device is formed faces up, and the center of the wafer W coincides with the rotation axis (Z axis) of the θ table 43. The cutting blade 33 is positioned on the outer peripheral portion of the wafer W so as to remove the chamfered portion W1 of the wafer W. At this time, the rotation axis (Y axis) of the cutting blade 33 is aligned with the center line of the wafer W. Then, cutting water is ejected from an ejection nozzle (not shown) and the cutting blade 33 is rotated at a high speed, and the chamfered portion W1 of the wafer W is cut by the cutting blade 33.

  Subsequently, as the chuck table 2 rotates, the chamfered portion W1 on the front side of the wafer W is cut into a circular shape in plan view, and a stepped groove W2 (see FIG. 6) along the outer periphery of the wafer W is formed. . The step-like groove W2 is cut deeper than a finish thickness t1 in a grinding process performed by a device different from the cutting device 1. For this reason, the outer peripheral portion of the wafer W after grinding does not remain in a knife edge shape on the outer peripheral portion of the wafer W, and the occurrence of cracks in the outer peripheral portion of the wafer W is prevented.

  7A and 7B are explanatory diagrams of edge trimming processing when uneven wear occurs in the wafer. In the edge trimming process, only one side (the left side in FIG. 6) of the cutting blade 33 contributes to the cutting, so that the cutting blade 33 is partially worn as shown in FIGS. 7A and 7B. Therefore, in the present embodiment, the edge trimming process is temporarily stopped at a predetermined timing (for example, every time the edge trimming process is performed on several wafers W), and the height of the cutting surface 33a of the cutting blade 33 is increased. Measurement (step S02) is performed.

  As shown in FIG. 4A, the height of the cutting surface 33a is measured by positioning the cutting blade 33 above the non-contact measuring unit 8 and then rotating the cutting blade 33 while projecting the light emitting unit 81 against the cutting surface 33a. The measurement light B is projected from Then, the index feed means 5 is driven to move the cutting blade 33 in the axial direction of the spindle 31 (Y-axis direction), and as shown in FIG. 4B, the irradiation position of the measuring light B is set to one end in the Y-axis direction of the cutting surface 33a. Relative displacement toward the other end. During this displacement, the light receiving unit 82 receives the measurement light B reflected by the cutting surface 33a, and the height position (Z-axis direction position) of the cutting surface 33a at a plurality of positions in the Y-axis direction that is the width direction of the cutting blade 33. ) Is measured.

  After the measurement of the height of the cutting surface 33a is completed, the quality determination (step S03) processing by the determination unit 91 is performed. In the quality determination, first, as shown in FIG. 7B, a difference value d between the maximum value that is the highest position in the Z-axis direction and the minimum value that is the lowest position is obtained from the measurement result of the cutting surface 33a. Then, the difference value d is compared with a predetermined value a stored in advance. Here, the specified value a is, for example, even if unevenness occurs in the shape of the bottom of the stepped groove W2 due to uneven wear of the cutting surface 33a, the bottom of the stepped groove W2 is smooth in a subsequent grinding process or the like. In the normal range that can be handled as a uniform or nearly uniform height.

  When the difference value d is smaller than the specified value a, the determination unit 91 makes a “good” determination as the degree to which the partial wear of the cutting surface 33a can allow the wafer W to be cut (step S03: “good”). The edge trimming process (step S01) is resumed. On the other hand, when the difference value d is equal to or greater than the specified value a, the determination unit 91 determines “No” as the degree of uneven wear of the cutting surface 33a making it difficult to continue cutting the wafer W (Step S03: “No”). ).

  When the determination unit 91 makes a “No” determination, the cutting blade 33 is dressed (step S04). In the dressing process, the rotating cutting blade 33 is brought into contact with the upper surface of the dresser board 7 so that the cutting surface 33a is parallel to the Y axis.

  After dressing, the height of the cutting surface 33a of the cutting blade 33 is measured (step S05). Since the height measurement is performed in the same manner as in step S02, description thereof is omitted here.

  Next, the control means 9 confirms the size of the cutting blade 33 (step S06). For this confirmation, the diameter dimension of the cutting blade 33 is calculated from the measurement result of the height position of the cutting surface 33a in step S05 and the Z-axis direction position of the spindle 31 stored in advance. If the diameter of the cutting blade 33 is smaller than the predetermined value, “NG” determination is made that the amount of wear of the cutting blade 33 is large and cutting cannot be continued (step S06: “NG”), and the cutting device 1 is driven. Stopped. In this case, the operator may be notified by notification means or the like (not shown) so as to replace the cutting blade 33.

  On the other hand, when the diameter of the cutting blade 33 is equal to or greater than the predetermined value, an “OK” determination is made that the amount of wear of the cutting blade 33 is small and the wafer W is allowed to continue cutting (step S06: “OK”). When the “OK” determination is made, the control means 9 calculates the Z axis direction from the position of the holding surface 21 (see FIG. 2) stored in advance and the measured height position of the cutting surface 33a. The distance is calculated. Then, the position in the Z-axis direction where the cutting surface 33a contacts the holding surface 21 is calculated as the reference position of the cutting feed means 6, and the cutting feed means 6 is driven and controlled according to the calculated reference position to determine the cutting blade 33. The height position is adjusted (step S07). Thereby, in the dressing process, the position of the cutting blade 33 in the Z-axis direction is corrected by the amount of change in the diameter of the cutting blade 33, and the formation position of the stepped groove W2 in the Z-axis direction is made uniform. And after adjusting the height position of the cutting blade 33, said edge trimming process (step S01) is restarted.

  As described above, according to the present embodiment, the non-contact measuring unit 8 measures the height position of the cutting surface 33a, and determines the quality of the cutting surface 33a from this measurement result. Even so, it is possible to eliminate uneven wear by dressing the cutting surface 33a. Thereby, the cutting depth of the stepped groove W2 can be accurately and uniformly cut on the wafer W, and it is possible to prevent a defective cutting. Further, the height position of the cutting surface 33a is measured even after dressing, and the height position of the cutting surface 33a is corrected from the result of this measurement. This also contributes to improving the accuracy of the formation position of the stepped groove W2. can do.

(Embodiment 2)
The second embodiment will be described below. In the second embodiment, components common to the first embodiment are denoted by the same reference numerals, and illustration and description thereof are omitted. FIG. 8 is a configuration diagram of a non-contact measurement unit according to Embodiment 2, FIG. 8A is a schematic side view, and FIG. 8B is a schematic front view. As shown in FIG. 8, the non-contact measuring unit 8a according to the second embodiment includes a light projecting unit 81a and a light receiving unit 82b, and is configured by a laser displacement meter using a strip laser beam. The light projecting unit 81a projects the measurement light B, which is a belt-shaped laser beam, toward the cutting surface 33a of the cutting blade 33 located above. The band width direction of the measurement light B by the light projecting unit 81a is positioned parallel to the axial direction (Y-axis direction) of the spindle 31, and the light is projected so that the band width increases as it approaches the cutting surface 33a. The light projecting direction of the measuring light B by the light projecting unit 81a is set parallel to the Z-axis direction perpendicular to the axial direction (Y-axis direction) of the spindle 31. The light receiving unit 82a receives the measurement light B reflected by the cutting surface 33a. The light receiving unit 82a includes a CCD, recognizes the shape of the cutting surface 33a by the strip-shaped measurement light B received by the CCD, and has the height (Z Measure the axial position).

  As described above, according to the present embodiment, it is possible to measure from one end to the other end in the Y-axis direction of the cutting surface 33a without driving the index feeding means 5, and simplification of drive control when measuring the height of the cutting surface 33a. Can be achieved.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, the non-contact measuring unit may be changed as long as the height of the cutting surface 33a can be measured in the same manner as in each of the above embodiments. As a specific example, the non-contact measuring unit according to the modification shown in FIGS. The structure of a contact measurement part is mentioned. The non-contact measuring unit 8b shown in FIG. 9 is constituted by a CCD camera, and images the cutting surface 33a from the tangential direction (X-axis direction) of the disc-shaped cutting blade 33 and performs image processing on the imaging result to perform cutting. The height (position in the Z-axis direction) of the surface 33a is measured.

  Further, the non-contact measuring unit 8c shown in FIG. 10 is configured by a projected dimension measuring instrument having a light projecting unit 81c and a light receiving unit 82c. The light projecting unit 81c projects light from the tangential direction (X-axis direction) of the cutting blade 33 onto the cutting surface 33a. The light receiving unit 82c receives light in a state where a shadow of the cutting surface is projected by the light projection of the light projecting unit 81c. The light receiving unit 82c performs image processing on the result of light reception to recognize the shape of the cutting surface 33a in the Y-axis direction and measures the height of the cutting surface 33a (position in the Z-axis direction).

  In addition, as described above, the determination by the determination unit 91 is performed by calculating the difference value d between the maximum value that is the highest position of the cutting surface 33a and the minimum value that is the lowest position and comparing it with the specified value a. The determination method is not limited to this, and may be changed as long as the height of the cutting surface 33a is measured and uneven wear can be recognized.

  As described above, the present invention has the effect of suppressing the occurrence of cutting failure due to uneven wear of the cutting blade and cutting the outer peripheral edge of the wafer with good accuracy.

DESCRIPTION OF SYMBOLS 1 Cutting device 2 Chuck table 3 Cutting means 43 (theta) table (rotating means)
5 Index feed means 6 Cutting feed means 8, 8a, 8b, 8c Non-contact measuring part 31 Spindle 33 Cutting blade W Wafer W1 Chamfering part

Claims (1)

A wafer having a chuck table holding a disk-shaped wafer, a rotating means for rotating the chuck table, and a cutting blade made of a disk-shaped cutting grindstone contacting the outer peripheral edge of the wafer held by the rotating chuck table. Cutting means for removing the chamfered portion of the outer peripheral edge of the cutting device,
The cutting means includes a spindle on which the cutting blade is rotatably mounted, a cutting feed means for moving the spindle in a direction to approach and separate from the chuck table, and an index feed for moving the spindle in the axial direction of the spindle. Means comprising at least
A non-contact measurement unit that measures the height of the outer peripheral edge of the cutting blade, and a determination unit that determines the quality of the outer peripheral end shape in the width direction of the cutting blade from the measurement result of the non-contact measurement unit ,
The non-contact measurement unit is a laser displacement meter using a spot laser beam,
The spot laser beam is projected from the light projecting unit in a direction perpendicular to the spindle axis toward the outer peripheral end of the cutting blade, and the light receiving unit that receives the reflected light reflected by the outer peripheral end of the cutting blade The height of the outer edge of the cutting blade can be measured,
The light projecting unit and the light receiving unit are provided side by side in the spindle axial direction,
The outer peripheral end of the cutting blade moved in the axial direction of the spindle by the index feeding means is measured by the non-contact measuring unit, and the height of the outer peripheral end of the cutting blade in the width direction of the cutting blade is measured. A cutting device.

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