JP6099507B2 - Cutting method - Google Patents

Description

  The present invention relates to a cutting method for cutting a workpiece such as a wafer, and more particularly, to a cutting method capable of adjusting a processing position and a cutting depth of a cutting blade used for cutting in a short time.

  A workpiece such as a semiconductor wafer having a device formed on the surface is cut by, for example, a cutting apparatus including an annular cutting blade. The processing position and cutting depth of the cutting blade may be deviated from the planned processing position and cutting depth due to the influence of the mounting accuracy and wear of the cutting blade.

  Therefore, the machining position and cutting depth of the cutting blade are adjusted before or during the cutting of the workpiece. As adjustment methods, there are known hairline alignment that aligns the reference line (hairline) of the camera used to control the processing position with the cutting groove, and setup that adjusts the cutting depth by cutting the cutting blade into the chuck table. (For example, refer to Patent Document 1 and Patent Document 2).

Japanese Patent Laid-Open No. 4-99607 JP 2011-82402 A

  However, in the above-described hairline matching, it is necessary to form a cutting groove for actually cutting the workpiece and matching the reference line. In the setup, the cutting blade must be moved to a setup position for cutting into the chuck table.

  For this reason, the above-described method has a problem that it takes a long time to adjust the machining position and the cutting depth. In particular, when the processing position and the cutting depth of the cutting blade must be adjusted in the middle of cutting, the time required for processing becomes long and productivity is lowered.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a cutting method capable of adjusting a processing position and a cutting depth of a cutting blade used for cutting in a short time. It is.

  According to the present invention, a rotatable holding means for holding a workpiece, a cutting blade having a cutting blade for cutting a cutting scheduled line set on the workpiece held by the holding means, and the cutting A cutting method comprising: a spindle to which a blade is mounted; and a cutting method for cutting a workpiece along the planned cutting line, wherein a direction parallel to an axis of the spindle is a Y direction, and the Y direction is The orthogonal direction is the X direction, the vertical direction orthogonal to the Y direction and the X direction is the Z direction, and the first light parallel to the X direction is moved to the Y direction while moving in the Y direction. Y-direction position detecting step for detecting the Y-direction position of the cutting edge of the cutting blade based on the first reflected light of the first light reflected toward the blade edge and in the Y direction The cutting blade is moved while moving parallel second light in the Z direction. A Z-direction position detecting step of detecting the Z-direction position of the cutting edge of the cutting blade based on the second reflected light of the second light reflected toward the cutting edge and reflected by the cutting edge; A holding step of holding the workpiece by a holding means, and setting the planned cutting line of the workpiece parallel to the X direction, and the Y direction of the cutting edge of the cutting blade detected in the Y direction position detecting step The cutting blade is positioned on the planned cutting line of the workpiece based on the position, and the cutting blade is set to a predetermined position based on the Z direction position of the cutting edge of the cutting blade detected in the Z direction position detecting step. After performing the cutting blade positioning step for positioning in the Z-direction position and the cutting blade positioning step, the rotating cutting blade and the workpiece are moved relative to each other in the X-direction, Object cutting method which is characterized in that and a cutting step of cutting along the preset cutting line is provided for.

  According to the present invention, the Y direction position of the cutting edge is detected based on the first reflected light reflected by the cutting blade, and the Z direction position of the cutting edge is detected based on the second reflected light reflected by the cutting blade.

  Thereby, the processing position and cutting depth of the cutting blade can be detected without cutting the work piece or the chuck table as in the prior art. That is, the processing position and cutting depth of the cutting blade can be adjusted in a short time.

It is a perspective view showing typically an example of composition of a cutting device with which a cutting method concerning this embodiment is implemented. It is a perspective view which shows typically the peripheral structure of a cutting blade. It is a figure which shows typically a Y direction position detection step. It is a figure which shows typically a Z direction position detection step. It is a perspective view which shows a cutting step typically.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The cutting method according to the present embodiment includes a Y-direction position detection step (see FIG. 3), a Z-direction position detection step (see FIG. 4), a holding step, a cutting blade positioning step, and a cutting step (see FIG. 5).

  In the Y-direction position detection step, the light irradiation area is set in the Y direction (index feed direction) while irradiating the first light propagating along the optical path parallel to the X direction (machining feed direction) toward the cutting blade. The position of the cutting edge in the Y direction is detected based on the first reflected light that is moved and reflected by the cutting edge of the cutting blade.

  In the Z-direction position detection step, while irradiating the cutting blade with the second light propagating along the optical path parallel to the Y-direction, the light irradiation area is moved in the Z-direction (vertical direction), and the cutting blade The Z direction position of the blade edge is detected based on the second reflected light reflected by the blade edge.

  In the holding step, the workpiece is held by the holding means, and the workpiece is aligned so that the scheduled cutting line of the workpiece is parallel to the X direction. In the cutting blade positioning step, the cutting blade is positioned on the planned cutting line of the workpiece based on the detected Y-direction position of the cutting edge, and the cutting blade is set to an appropriate Z based on the detected Z-direction position of the cutting edge. Position in the direction position.

  In the cutting step, the rotated cutting blade is cut into the planned cutting line of the workpiece, and the cutting blade and the workpiece are relatively moved in the X direction to cut the workpiece along the planned cutting line. To do. Hereinafter, the cutting method according to the present embodiment will be described in detail.

  First, a cutting apparatus in which the cutting method according to the present embodiment is performed will be described. FIG. 1 is a perspective view schematically showing a configuration example of a cutting device. As shown in FIG. 1, the cutting device 2 includes a base 4 that supports each component.

  A chuck table (holding means) 6 for holding a wafer (workpiece) 11 (see FIG. 5) is provided on the upper surface of the base 4. A blade unit (cutting means) 8 for cutting the wafer 11 is disposed above the chuck table 6.

  The wafer 11 is, for example, a disk-shaped semiconductor wafer, and is supported by an annular frame 15 (see FIG. 5) via a sheet 13 (see FIG. 5) attached to the back side. However, the configuration of the wafer 11 is not particularly limited.

  Below the chuck table 6, an X-axis moving mechanism (machining feed means) 10 for moving the chuck table 6 in the machining feed direction (X direction) is provided. The X-axis moving mechanism 10 includes a pair of X-axis guide rails 12 fixed to the upper surface of the base 4 and parallel to the X direction.

  An X-axis moving table 14 is slidably installed on the X-axis guide rail 12. A nut (not shown) is fixed to the rear surface side (lower surface side) of the X-axis moving table 14, and an X-axis ball screw 16 parallel to the X-axis guide rail 12 is screwed to the nut.

  An X-axis pulse motor 18 is connected to one end of the X-axis ball screw 16. If the X-axis ball screw 16 is rotated by the X-axis pulse motor 18, the X-axis moving table 14 moves in the X direction along the X-axis guide rail 12.

  A support base 20 is provided on the surface side (upper surface side) of the X-axis moving table 14. A chuck table 6 is disposed in the center of the support table 20. Around the chuck table 6 are provided four clamps 22 for holding and fixing an annular frame 15 supporting the wafer 11 from four directions.

  The chuck table 6 is connected to a rotation mechanism (not shown) provided below the support base 20 and rotates around the Z axis (vertical axis). The surface of the chuck table 6 is a holding surface 6 a that holds the wafer 11 by suction. A negative pressure of a suction source (not shown) acts on the holding surface 6 a through a flow path (not shown) formed inside the chuck table 6, and a suction force for sucking the wafer 11 is generated.

  Adjacent to the X-axis moving mechanism 10, a Y-axis moving mechanism (index feeding means) 24 for moving the blade unit 8 in the index feeding direction (Y direction) is provided. The Y-axis moving mechanism 24 includes a pair of Y-axis guide rails 26 that are fixed to the upper surface of the base 4 and are parallel to the Y direction.

  A Y-axis moving table 28 is slidably installed on the Y-axis guide rail 26. The Y-axis moving table 28 includes a base portion 28a that is in contact with the Y-axis guide rail 26, and a wall portion 28b that is erected with respect to the base portion 28a.

  A nut (not shown) is fixed to the back surface (lower surface) of the base portion 28a of the Y-axis moving table 28, and a Y-axis ball screw 30 parallel to the Y-axis guide rail 26 is screwed to the nut. ing.

  A Y-axis pulse motor 32 is connected to one end of the Y-axis ball screw 30. When the Y-axis ball motor 30 is rotated by the Y-axis pulse motor 32, the Y-axis moving table 28 moves in the Y direction along the Y-axis guide rail 26.

  A Z-axis moving mechanism 34 that moves the blade unit 8 in the vertical direction (Z direction) is provided on the wall 28 b of the Y-axis moving table 28. The Z-axis moving mechanism 34 includes a pair of Z-axis guide rails 36 that are fixed to the side surface of the wall portion 28b and are parallel to the Z direction.

  A Z-axis moving table 38 is slidably installed on the Z-axis guide rail 36. A nut (not shown) is fixed to the back surface side (wall portion 28b side) of the Z-axis moving table 38, and a Z-axis ball screw (not shown) parallel to the Z-axis guide rail 36 is screwed to the nut. Are combined.

  A Z-axis pulse motor 40 is connected to one end of the Z-axis ball screw. When the Z-axis ball screw is rotated by the Z-axis pulse motor 40, the Z-axis moving table 38 moves in the Z direction along the Z-axis guide rail 36.

  The Z-axis moving table 38 supports a spindle housing 44 that rotatably accommodates a spindle 42 (see FIGS. 3 and 4) having an axis parallel to the Y direction. An annular cutting blade 46 is attached to one end of the spindle 42, and a motor (not shown) is connected to the other end of the spindle. The wafer 11 is cut by rotating the cutting blade 46 with a motor and cutting it into the wafer 11 held on the chuck table 6.

  A controller (not shown) is connected to each component such as the chuck table 6, the blade unit 8, the X-axis moving mechanism 10, the Y-axis moving mechanism 24, and the Z-axis moving mechanism 34. The control device controls the operation of each component based on various conditions set by the operator.

  FIG. 2 is a perspective view schematically showing the peripheral structure of the cutting blade 46. As shown in FIG. 2, a wheel cover 48 that accommodates the cutting blade 46 is attached to one end side of the spindle housing 44. The outer periphery of the cutting blade 46 is covered with a wheel cover 48 except for the lower part.

  The cutting blade 46 is fixed so as to be sandwiched between a flange 50 (see FIGS. 3 and 4) attached to the tip portion of the spindle 42 and a fixing nut 52. The cutting blade 46 is a hub blade, and a cutting blade 46b for cutting the wafer 11 is provided on the outer periphery of an annular support base 46a.

  The cutting blade 46b is formed in an annular shape by bonding abrasive grains such as diamond with a bonding material, and has a thickness of about 10 μm to 500 μm, for example. In the present embodiment, a hub blade is exemplified as the cutting blade 46, but the type of the cutting blade 46 is not particularly limited. A washer blade or the like may be used as the cutting blade 46.

  Below the wheel cover 48, a pair of substantially L-shaped nozzles 54 that sandwich the lower part of the cutting blade 46 in the front-rear direction are provided. Cutting water is supplied to the nozzle 54 through a connecting portion 56 provided on the upper portion of the wheel cover 48. A plurality of slits (not shown) are formed on the tip side of the nozzle 54 so as to face the cutting blade 46. The machining point is cooled and cleaned by cutting water sprayed through the plurality of slits.

  A first laser displacement meter (Y direction position detecting means) 58 is disposed on the proximal end side of the nozzle 54 so as to be sandwiched between the pair of nozzles 54. The first laser displacement meter 58 includes a first irradiation unit (not shown) that emits a laser beam (first light) toward the cutting blade 46b of the cutting blade 46, and a laser beam (not shown) reflected by the cutting blade 46b. And a first light receiving unit (not shown) that receives the first reflected light.

  The 1st irradiation part of the 1st laser displacement meter 58 is arrange | positioned so that a laser beam can be propagated to a X direction. That is, the optical path of the laser beam emitted from the first irradiation unit of the first laser displacement meter 58 is parallel to the X direction.

  The first laser displacement meter 58 is attached to the wheel cover 48 via a first moving mechanism including a pulse motor, and moves in the Y direction. Thereby, the irradiation area can be moved in the Y direction while irradiating the cutting blade 46 with the laser beam.

  The position of the first laser displacement meter 58 in the Y direction with respect to the wheel cover 48 is known to the cutting device 2. Therefore, the irradiation region is moved in the Y direction while irradiating the cutting blade 46 with the laser beam, and the reflected light (first reflected light) reflected by the cutting blade 46b is received by the first light receiving unit. The position of the cutting edge in the Y direction can be detected based on the change in the amount of light received by one light receiving unit.

  Near the upper end of the cutting blade 46, a second laser displacement meter (Z-direction position detecting means) 60 (see FIG. 4) is arranged. The second laser displacement meter 60 also includes a second irradiation unit that irradiates a laser beam (second light) toward the cutting blade 46b of the cutting blade 46, and a laser beam (second reflection) reflected by the cutting blade 46b. And a second light receiving portion for receiving light.

  The 2nd irradiation part of the 2nd laser displacement meter 60 is arranged so that a laser beam can be propagated in the Y direction. That is, the optical path of the laser beam emitted from the second irradiation unit of the second laser displacement meter 60 is parallel to the Y direction.

  The second laser displacement meter 60 is attached to the wheel cover 48 via a second moving mechanism including a pulse motor, and moves in the Z direction. Thereby, the irradiation area can be moved in the Z direction while irradiating the cutting blade 46 with the laser beam.

  The Z-direction position of the second laser displacement meter 60 with respect to the wheel cover 48 is known to the cutting device 2. Therefore, the irradiation region is moved in the Z direction while irradiating a laser beam toward the cutting blade 46, and the reflected light (second reflected light) reflected by the cutting blade 46b is received by the second light receiving unit. The position of the cutting edge in the Z direction can be detected based on the change in the amount of light received by the two light receiving portions.

  In the cutting method according to the present embodiment, first, in the cutting apparatus 2 described above, a Y-direction position detection step of detecting the Y-direction position of the cutting edge of the cutting blade 46 is performed. FIG. 3 is a diagram schematically showing the Y-direction position detection step.

  As shown in FIG. 3, in the Y direction position detecting step, a laser beam (first light) is irradiated toward the cutting blade 46b of the cutting blade 46 while moving the first laser displacement meter 58 in the Y direction. . Thereby, the laser beam is irradiated to the cutting blade 46b while moving in the Y direction.

  At the same time, the reflected laser beam (first reflected light) is received by the first laser displacement meter 58. Thereby, a change in the amount of received light in the Y direction can be detected. Here, the reflectance of the laser beam changes abruptly at the end of the cutting blade 46 in the Y direction.

  That is, the amount of light received by the first laser displacement meter 58 changes abruptly in a region corresponding to the end of the cutting blade 46 in the Y direction. The control device of the cutting device 2 detects the position of the cutting edge in the Y direction based on this sudden change in the amount of received light.

  After the Y-direction position detection step, a Z-direction position detection step for detecting the Z-direction position of the cutting edge of the cutting blade 46 is performed. FIG. 4 is a diagram schematically illustrating the Z-direction position detection step.

  As shown in FIG. 4, in the Z direction position detecting step, a laser beam (second light) is irradiated toward the cutting blade 46b of the cutting blade 46 while moving the second laser displacement meter 60 in the Z direction. . Thereby, the laser beam is irradiated to the cutting blade 46b while moving in the Z direction.

  At the same time, the reflected laser beam (second reflected light) is received by the second laser displacement meter 60. Thereby, a change in the amount of received light in the Z direction can be detected. The amount of light received by the second laser displacement meter 60 changes abruptly in a region corresponding to the end of the cutting blade 46 in the Z direction. The control device of the cutting device 2 detects the position of the cutting edge in the Z direction based on this rapid change in the amount of received light.

  After the Y-direction position detection step and the Z-direction position detection step, a holding step for sucking and holding the wafer 11 on the chuck table 6 of the cutting apparatus 2 is performed. First, the sheet 13 adhered to the back side of the wafer 11 is brought into contact with the holding surface 6a of the chuck table 6 to apply a negative pressure of the suction source.

  The front surface side of the wafer 11 is divided into a plurality of regions by streets (planned cutting lines) 17 (see FIG. 5) arranged in a grid pattern, and each region has a device 19 (see FIG. 5) such as an IC. Is formed. As described above, after the wafer 11 is sucked and held on the chuck table 6 via the sheet 13, the chuck table 6 is rotated around the Z axis so that the street 17 and the X direction are parallel to each other.

  After the holding step, the cutting blade positioning step of adjusting the Y direction position of the cutting blade 46 based on the detected Y direction position and adjusting the Z direction position of the cutting blade 46 based on the detected Z direction position. To implement.

  First, based on the Y-direction position of the cutting edge detected in the Y-direction position detection step described above, the control device of the cutting device 2 calculates a deviation amount from an appropriate Y-direction position. Based on the calculated deviation amount, the Y direction position of the cutting blade 46 is adjusted so that the street 17 of the wafer 11 and the cutting position of the cutting blade 46 coincide with each other.

  Next, based on the Z direction position of the cutting edge detected in the Z direction position detection step, the control device of the cutting device 2 calculates a deviation amount from an appropriate Z direction position. Then, based on the calculated deviation amount, the Z-direction position of the cutting blade 46 is adjusted so that the cutting amount of the cutting blade 46 is appropriate.

  By this cutting blade positioning step, the cutting blade 46 is positioned on the street 17 of the wafer 11 and at an appropriate Z-direction position. In the present embodiment, the cutting blade positioning step is performed by automatic control of the control device, but may be performed by an operator's manual operation.

  After the cutting blade positioning step, a cutting step for cutting the wafer 11 along the street 17 is performed. FIG. 5 is a perspective view schematically showing a cutting step.

  In the cutting step, first, the cutting blade 46 is positioned on the street 17 designated as the start position. Then, the rotating cutting blade 46 is cut into the wafer 11 held on the chuck table 6 and the chuck table 6 is moved (processed) in the X direction.

  Thereby, the wafer 11 is cut along the target street 17. Subsequently, the cutting blade 46 is raised and then moved (indexed) in the Y direction to align with the adjacent street 17. Then, the cutting blade 46 is cut into the wafer 11 and the chuck table 6 is moved in the X direction.

  Thus, after cutting the wafer 11 along all the streets 17 extending in the first direction by repeating the processing feed and the indexing feed, the wafer 11 is rotated by 90 ° to extend in the second direction. The wafer 11 is cut along the street 17. When the wafer 11 is cut along all the streets 17, the cutting step ends.

  As described above, in the cutting method of the present embodiment, the position of the cutting edge in the Y direction is detected based on the laser beam (first reflected light) reflected by the cutting edge of the cutting blade 46 and reflected by the cutting edge of the cutting blade 46. The position of the cutting edge in the Z direction is detected based on the laser beam (second reflected light).

  Thereby, the processing position and cutting depth of the cutting blade 46 can be detected without cutting the wafer (workpiece) 11 and the chuck table 6 as in the prior art. That is, the processing position and cutting depth of the cutting blade 46 can be adjusted in a short time.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. For example, in the above embodiment, the Z-direction position detection step is performed after the Y-direction position detection step, but the Z-direction position detection step may be performed first. Further, the Y-direction position detection step and the Z-direction position detection step may be performed simultaneously.

  In the above embodiment, the Z direction position is adjusted after adjusting the Y direction position in the cutting blade positioning step. However, the Z direction position may be adjusted first. Further, the adjustment in the Y direction position and the adjustment in the Z direction position may be performed simultaneously.

  In addition, the configurations, methods, and the like according to the above-described embodiments can be changed as appropriate without departing from the scope of the object of the present invention.

2 Cutting device 4 Base 6 Chuck table (holding means)
6a Holding surface 8 Blade unit (cutting means)
10 X axis movement mechanism (machining feed means)
12 X-axis guide rail 14 X-axis moving table 16 X-axis ball screw 18 X-axis pulse motor 20 Support base 22 Clamp 24 Y-axis moving mechanism (index feed means)
26 Y-axis guide rail 28 Y-axis moving table 28a Base 28b Wall 30 Y-axis ball screw 32 Y-axis pulse motor 34 Z-axis moving mechanism 36 Z-axis guide rail 38 Z-axis moving table 40 Z-axis pulse motor 42 Spindle 44 Spindle housing 46 Cutting blade 46a Support base 46b Cutting blade 48 Wheel cover 50 Flange 52 Fixing nut 54 Nozzle 56 Connecting portion 58 First laser displacement meter (Y direction position detecting means)
60 Second laser displacement meter (Z-direction position detecting means)
11 Wafer (Workpiece)
13 Sheet 15 Frame 17 Street (Scheduled cutting line)
19 devices

Claims (1)

A rotatable holding means for holding a workpiece, a cutting blade having a cutting blade for cutting a scheduled cutting line set on the workpiece held by the holding means, and a spindle on which the cutting blade is mounted And a cutting method for cutting a workpiece along the planned cutting line with a cutting device comprising:
The direction parallel to the spindle axis is the Y direction, the direction orthogonal to the Y direction is the X direction, and the vertical direction orthogonal to the Y direction and the X direction is the Z direction,
The first light parallel to the X direction is projected toward the cutting edge of the cutting blade while moving in the Y direction, and based on the first reflected light of the first light reflected by the cutting edge, A Y-direction position detecting step for detecting the Y-direction position of the cutting edge of the cutting blade;
Second light parallel to the Y direction is projected toward the cutting edge of the cutting blade while moving in the Z direction, and based on the second reflected light of the second light reflected by the cutting edge A Z-direction position detecting step for detecting the Z-direction position of the cutting edge of the cutting blade;
A holding step of holding the workpiece by holding means and making the cutting line of the workpiece parallel to the X direction;
Based on the Y direction position of the cutting edge of the cutting blade detected in the Y direction position detecting step, the cutting blade is positioned on the planned cutting line of the workpiece, and is detected in the Z direction position detecting step. A cutting blade positioning step of positioning the cutting blade at a predetermined Z-direction position based on the Z-direction position of the cutting edge of the cutting blade;
After performing the cutting blade positioning step, the cutting step of relatively moving the rotating cutting blade and the workpiece in the X direction to cut the workpiece along the planned cutting line with the cutting blade; A cutting method comprising:

Images