JP2015099844A - Processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing device capable of subjecting a desired position to uniform processing from a lower surface of a processing object held on a chuck table.SOLUTION: The processing device includes: height position detection means 56 which detects a height position in a Z axis direction of a holding surface of a chuck table 36; and control means including a memory having a first storage area in which gaps in an X axis direction and a Y axis direction between the height position detection means and a processing part of processing means are stored and a second storage area in which Z coordinate values for respective XY coordinate values on the holding surface of the chuck table are stored. The control means adds the gaps in the X axis direction and the Y axis direction between the height position detection means and the processing part, which are stored in the first storage area of the memory, to the XY coordinate values stored in the second storage area of the memory, on the basis of detection signals from X axis-direction position detection means 374 and Y axis-direction position detection means 384 to obtain a Z coordinate value for XY coordinate values corresponding to the processing part and controls Z axis movement means 55 on the basis of the obtained Z coordinate value for the XY coordinate values.

Description

  The present invention relates to a processing apparatus such as a cutting apparatus or a laser processing apparatus for performing cutting or laser processing on a workpiece such as a semiconductor wafer.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by division lines arranged in a lattice pattern on the surface of a substantially disc-shaped semiconductor wafer, and devices such as ICs and LSIs are formed in the partitioned regions. . Then, by cutting the semiconductor wafer along the planned dividing line, the region where the device is formed is divided to manufacture individual devices. In addition, an optical device wafer in which a gallium nitride compound semiconductor or the like is laminated on the surface of a sapphire substrate or a silicon carbide substrate is also divided into optical devices such as individual light-emitting diodes and laser diodes by cutting along the planned dividing line. Widely used in electrical equipment.

  Cutting along the division lines such as the above-described semiconductor wafers and optical device wafers is usually performed by a cutting device called a dicer. This cutting apparatus includes a chuck table for holding a workpiece such as a semiconductor wafer or an optical device wafer, a cutting means for cutting the workpiece held on the chuck table, and a chuck table and the cutting means. And a cutting feed means for moving it. The cutting means includes a rotary spindle, a cutting blade mounted on the spindle, and a drive mechanism that rotationally drives the rotary spindle. The cutting blade is composed of a disk-shaped base and an annular cutting edge mounted on the outer periphery of the side surface of the base. The cutting edge is fixed to the base by electroforming, for example, diamond abrasive grains having a particle size of about 3 μm. The thickness is about 30 μm (see, for example, Patent Document 1).

  However, since the cutting blade has a thickness of about 30 μm, a line to be divided that divides the device needs to have a width of about 50 μm. For this reason, for example, in the case of a device having a size of about 1 mm × 1 mm, there is a problem that the area ratio occupied by the planned division line increases and the productivity is poor. Further, when the wafer is cut with a cutting blade, there is a problem in that chipping occurs on the lower surface side of the cut surface and the quality of the device is lowered.

  On the other hand, in recent years, as a method of dividing a plate-like workpiece such as a semiconductor wafer, a pulsed laser beam having a wavelength that is transparent to the wafer is used, and the focused laser beam is aligned with the inside of the region to be divided. Laser processing methods for irradiation have been attempted. In this dividing method using the laser processing method, a laser beam having a wavelength that is transmissive to the wafer is positioned from one surface side of the wafer to the inside of the line corresponding to the line to be divided, along the line to be divided. Irradiation is performed to continuously form a modified layer along the planned dividing line inside the wafer, and by applying an external force along the planned dividing line whose strength is reduced by the formation of the modified layer, Is divided into individual devices, and the width of the planned division line can be minimized (see, for example, Patent Document 2).

  In addition, as a wafer dividing technique capable of minimizing the width of the planned dividing line, the applicant positions the cutting blade along the planned dividing line from the back side of the wafer, and places the cutting blade on the surface in the region corresponding to the planned dividing line. A cutting groove is formed while leaving a predetermined thickness that is not reached, and then an external force is applied to the wafer in which the cutting groove is formed to divide the wafer into individual devices along the planned dividing line in which the cutting groove is formed. The technology was proposed as Japanese Patent Application No. 2012-198217.

Japanese Patent Laid-Open No. 2002-66865 Japanese Patent No. 3408805

Thus, the holding surface of the chuck table having the holding surface for holding the workpiece has a slight amount of undulation, and the wafer is held on the holding surface following the undulation. There are the following problems.
In the wafer splitting technique using the laser processing method described above, even though the laser beam is irradiated from the back surface of the wafer and the focal point of the laser beam is positioned at a desired position from the wafer surface, the position of the modified layer is the surface of the wafer. When the wafer is divided by applying an external force to the wafer, the cracks are not uniform and the quality of the device is not stable.
Further, in the wafer dividing technique for forming the above-mentioned cutting groove, even if the cutting blade is intended to be positioned at a desired position (for example, 15 μm) from the front surface of the wafer when cutting along the scheduled dividing line from the back surface of the wafer, When the bottom of the groove is too close or too far to the surface of the wafer, it becomes non-uniform, and when the wafer is divided by applying external force, the cracks become non-uniform and the device quality is not stable. is there.

  The present invention has been made in view of the above facts, and a main technical problem thereof is to provide a processing apparatus capable of performing uniform processing at a desired position from the lower surface of the workpiece held on the chuck table. There is.

In order to solve the above main technical problem, according to the present invention, a chuck table having a holding surface for holding a workpiece, a processing means for processing the workpiece held on the holding surface of the chuck table, X-axis moving means for relatively moving the chuck table and the processing means in the X-axis direction, and Y-axis movement for relatively moving the chuck table and the processing means in the Y-axis direction perpendicular to the X-axis direction Means, Z-axis moving means for moving the processing means in the Z-axis direction orthogonal to the X-axis direction and the Y-axis direction, and an X-axis direction position detecting means for detecting the chuck table moving position by the X-axis moving means Y-axis direction position detecting means for detecting the chuck table moving position by the Y-axis moving means, and Z-axis direction position detecting means for detecting the Z-axis direction position of the processing means by the Z-axis moving means. A processing device,
A height position detecting means arranged adjacent to the processing means for detecting the height position of the holding surface of the chuck table in the Z-axis direction;
A first storage area for storing an interval in the X-axis direction and the Y-axis direction between the height position detecting means and a processing portion by the processing means; and a holding surface of the chuck table detected by the height position detecting means A control means comprising a memory having a second storage area for storing a Z coordinate value for each XY coordinate value in
The control means converts the XY coordinate values stored in the second storage area of the memory into the first storage area of the memory based on the detection signals from the X-axis direction position detection means and the Y-axis direction position detection means. The stored height position detection means and the distance between the machining part by the machining means and the X-axis direction and the Y-axis direction are added to convert the Z coordinate value to the XY coordinate value corresponding to the machining part by the machining means. , Controlling the Z-axis moving means based on the Z coordinate value for the converted XY coordinate value,
A processing apparatus characterized by that.

A processing apparatus according to the present invention is provided adjacent to a processing means for processing a workpiece held on a holding surface of a chuck table having a holding surface for holding the workpiece, and is in the Z-axis direction of the holding surface of the chuck table. Height position detecting means for detecting the height position of the first position, a first storage area for storing the distance between the height position detecting means and the processing portion by the processing means in the X-axis direction and the Y-axis direction, and height position detection Control means comprising a memory having a second storage area for storing the Z coordinate value for each XY coordinate value on the holding surface of the chuck table detected by the means, and the control means detects the position in the X-axis direction. Based on the detection signal from the means and the Y-axis direction position detection means, the XY coordinate value stored in the second storage area of the memory is changed to the height position detection means and processing means stored in the first storage area of the memory. And processed parts by The intervals in the X-axis direction and the Y-axis direction are added and converted into a Z-coordinate value corresponding to the XY coordinate value corresponding to the processing portion by the processing means, and the Z-axis moving means is converted based on the Z-coordinate value corresponding to the converted XY coordinate value. Since the holding surface, which is the upper surface of the chuck table, has a slight undulation, even if the workpiece is held on the holding surface following the undulation, the workpiece can be processed from the lower surface of the workpiece to a desired position. it can.
Therefore, when the present invention is applied to a cutting device for cutting a wafer, even if the holding surface, which is the upper surface of the chuck table, has slight undulations, even if the wafer surface is held by the holding surface following the undulations, A cutting blade as a processing means for cutting can be positioned at a desired position from the surface of the wafer, and the position of the bottom of the cutting groove is not too close or too far from the surface. For this reason, in the wafer dividing step, which is the next step, when an external force is applied to the wafer and the wafer is divided along the cutting grooves, the division along each cutting groove becomes uniform and the quality of the device is stabilized.
In addition, by applying the present invention to a laser processing apparatus, even if the holding surface, which is the upper surface of the chuck table, has a slight amount of undulation, even if the surface of the wafer is held by the holding surface following the undulation, from the back side of the wafer When irradiating a laser beam, it becomes possible to position the condensing point of the laser beam at a desired position from the surface of the wafer to form a modified layer, and the position of the modified layer may be too close or too far from the surface. Absent. Therefore, in the next wafer dividing step, when an external force is applied to the wafer and the wafer is divided along the modified layer, the division along each modified layer becomes uniform and the device quality is stabilized.

The perspective view of the cutting device as a processing apparatus comprised according to this invention. The block diagram of the control means with which the cutting apparatus shown in FIG. 1 is equipped. Explanatory drawing which shows the relationship with the coordinate position in the state located in the chuck table predetermined position with which the cutting apparatus shown in FIG. 1 is equipped. The perspective view of the semiconductor wafer as a to-be-processed object. FIG. 5 is a perspective view showing a state in which the semiconductor wafer shown in FIG. 4 is attached to the surface of a protective tape attached to an annular frame. Explanatory drawing of the cutting groove formation process implemented with the cutting device shown in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a processing apparatus configured according to the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a cutting device as a processing device configured according to the present invention.
The cutting apparatus shown in FIG. 1 includes a stationary base 2, a chuck table mechanism 3 that is disposed on the stationary base 2 so as to be movable in the X-axis direction indicated by an arrow X, and holds a workpiece. A spindle support mechanism 4 is provided on the table 2 so as to be movable in the Y-axis direction indicated by an arrow Y orthogonal to the X-axis direction, and the spindle support mechanism 4 is indicated by an arrow Z orthogonal to the X-axis direction and the Y-axis direction. A spindle unit 5 is provided as a cutting means, which is a processing means arranged to be movable in the Z-axis direction (a direction perpendicular to the holding surface of the chuck table described later).

  The chuck table mechanism 3 includes a pair of guide rails 31 and 31 disposed in parallel along the X-axis direction on the stationary base 2, and is arranged on the guide rails 31 and 31 so as to be movable in the X-axis direction. A first sliding block 32 provided, a second sliding block 33 movably disposed on the first sliding block 32 in the Y-axis direction, and a cylindrical member on the second sliding block 33 A cover table 35 supported by 34 and a chuck table 36 as a workpiece holding means are provided. The chuck table 36 includes a suction chuck 361 formed of a porous material, and holds, for example, a disk-shaped semiconductor wafer, which is a workpiece, on a holding surface which is the upper surface of the suction chuck 361 by suction means (not shown). It is supposed to be. The chuck table 36 configured as described above is rotated by a pulse motor 340 disposed in the cylindrical member 34. The chuck table 36 is provided with a clamp 362 for fixing an annular frame described later.

  The first sliding block 32 has a pair of guided grooves 321 and 321 fitted to the pair of guide rails 31 and 31 on the lower surface thereof, and is parallel to the upper surface along the Y-axis direction. A pair of formed guide rails 322 and 322 are provided. The first sliding block 32 configured in this way moves in the X-axis direction along the pair of guide rails 31, 31 when the guided grooves 321, 321 are fitted into the pair of guide rails 31, 31. Configured to be possible. The chuck table mechanism 3 in the illustrated embodiment includes an X-axis moving means 37 for moving the first sliding block 32 along the pair of guide rails 31, 31 in the X-axis direction. The X-axis moving means 37 includes a male screw rod 371 disposed in parallel between the pair of guide rails 31 and 31, and a drive source such as a pulse motor 372 for rotationally driving the male screw rod 371. . One end of the male screw rod 371 is rotatably supported by a bearing block 373 fixed to the stationary base 2, and the other end is connected to the output shaft of the pulse motor 372 by transmission. The male screw rod 371 is screwed into a penetrating female screw hole formed in a female screw block (not shown) provided on the lower surface of the central portion of the first sliding block 32. Therefore, when the male screw rod 371 is driven forward and backward by the pulse motor 372, the first sliding block 32 is moved along the guide rails 31, 31 in the X-axis direction.

  The chuck table mechanism 3 in the illustrated embodiment includes X-axis direction position detecting means 374 for detecting the position of the chuck table 36 in the X-axis direction. The X-axis direction position detecting means 374 moves along the linear scale 374a together with the linear scale 374a disposed along the guide rail 31 and the first sliding block 32 along the linear scale 374a. It consists of a read head 374b. In the illustrated embodiment, the read head 374b of the X-axis direction position detecting means 374 sends a pulse signal of one pulse every 1 μm to the control means described later.

  The second sliding block 33 is provided with a pair of guided grooves 331 and 331 which are fitted to a pair of guide rails 322 and 322 provided on the upper surface of the first sliding block 32 on the lower surface thereof. By fitting the guided grooves 331 and 331 to the pair of guide rails 322 and 322, the guided grooves 331 and 331 are configured to be movable in the Y-axis direction. The chuck table mechanism 3 in the illustrated embodiment includes a first Y for moving the second sliding block 33 in the Y-axis direction along a pair of guide rails 322 and 322 provided in the first sliding block 32. An axis moving means 38 is provided. The first Y-axis moving means 38 includes a driving source such as a male screw rod 381 disposed in parallel between the pair of guide rails 322 and 322, and a pulse motor 382) for driving the male screw rod 381 to rotate. Is included. One end of the male screw rod 381 is rotatably supported by a bearing block 383 fixed to the upper surface of the first slide block 32, and the other end is connected to the output shaft of the pulse motor 382. The male screw rod 381 is screwed into a through female screw hole formed in a female screw block (not shown) provided on the lower surface of the center portion of the second sliding block 33. Therefore, the second sliding block 33 is moved in the Y-axis direction along the guide rails 322 and 322 by driving the male screw rod 381 forward and backward by the pulse motor 382.

  The chuck table mechanism 3 in the illustrated embodiment includes Y-axis direction position detecting means 384 for detecting the Y-axis direction position of the second sliding block 33 (chuck table 36). The Y-axis direction position detecting means 384 is a linear scale 384a disposed along the guide rail 322, and a reading which is disposed along the linear scale 384a together with the second sliding block 33 disposed along the second sliding block 33. And a head 384b. In the illustrated embodiment, the reading head 384b of the Y-axis direction position detecting means 384 sends a pulse signal of one pulse every 1 μm to the control means described later.

  The spindle support mechanism 4 includes a pair of guide rails 41 and 41 arranged in parallel along the Y-axis direction indicated by an arrow Y on the stationary base 2 and the Y-axis direction on the guide rails 41 and 41. A movable support base 42 is provided so as to be movable. The movable support base 42 includes a movement support portion 421 that is movably disposed on the guide rails 41, 41, and a mounting portion 422 that is attached to the movement support portion 421. The mounting portion 422 is provided with a pair of guide rails 423 and 423 extending in the Z-axis direction, which is a cutting feed direction indicated by an arrow Z perpendicular to the workpiece holding surface of the chuck table 36, on one side surface. . The spindle support mechanism 4 in the illustrated embodiment includes second Y-axis moving means 43 for moving the movable support base 42 along the pair of guide rails 41 and 41 in the Y-axis direction. The second Y-axis moving means 43 is provided with a drive source such as a male screw rod 431 disposed in parallel between the pair of guide rails 41, 41, and a pulse motor 432 for rotationally driving the male screw rod 431. Contains. One end of the male screw rod 431 is rotatably supported by a bearing block (not shown) fixed to the stationary base 2, and the other end is connected to the output shaft of the pulse motor 432. The male screw rod 431 is screwed into a female screw hole formed in a female screw block (not shown) provided on the lower surface of the central portion of the moving support portion 421 constituting the movable support base 42. For this reason, when the male screw rod 431 is driven to rotate forward and reversely by the pulse motor 432, the movable support base 42 is moved along the guide rails 41, 41 in the Y-axis direction.

  The spindle unit 5 in the illustrated embodiment includes a unit holder 51, a spindle housing 52 attached to the unit holder 51, and a rotating spindle 53 that is rotatably supported by the spindle housing 52. The unit holder 51 is provided with a pair of guided grooves 511 and 511 that are slidably fitted to a pair of guide rails 423 and 423 provided in the mounting portion 422. By being fitted to the guide rails 423 and 423, the guide rails 423 and 423 are supported so as to be movable in the Z-axis direction that is a cutting feed direction perpendicular to the holding surface of the chuck table 36. The rotary spindle 53 is disposed so as to protrude from the tip of the spindle housing 52, and the cutting blade 6 is attached to the tip of the rotary spindle 53. Note that the rotary spindle 53 on which the cutting blade 6 is mounted is driven to rotate by a drive source such as a servo motor 54.

  The spindle unit 5 in the illustrated embodiment includes Z-axis moving means 55 for moving the holder 51 along the two guide rails 423 and 423 in the Z-axis direction. The Z-axis moving means 55 is a male screw rod (see FIG. 5) disposed between the guide rails 423 and 423 in the same manner as the X-axis moving means 37, the first Y-axis moving means 38, and the second Y-axis moving means 43. And a drive source such as a pulse motor 552 for rotationally driving the male screw rod, and by driving the male screw rod (not shown) forward and reverse by the pulse motor 552, the unit holder 51 and the spindle housing 52 and the rotary spindle 53 are moved along the guide rails 423 and 423 in the Z-axis direction.

  The spindle unit 5 in the illustrated embodiment includes Z-axis direction position detecting means 56 for detecting the Z-axis direction position (cutting feed position) of the cutting blade 6. The Z-axis direction position detecting means 56 includes a linear scale 56a arranged in parallel with the guide rails 423 and 423, a reading head 56b attached to the unit holder 51 and moving along the linear scale 56a together with the unit holder 51. It is made up of. In the illustrated embodiment, the reading head 56b of the Z-axis direction position detecting means 56 sends a pulse signal of one pulse every 1 μm to the control means described later.

  The cutting apparatus in the illustrated embodiment includes an imaging means 7 disposed at the front end portion of the spindle housing 52. The imaging means 7 includes an infrared illumination means for irradiating a workpiece with infrared rays, an optical system for capturing infrared rays emitted by the infrared illumination means, in addition to a normal imaging device (CCD) for imaging with visible light, An image sensor (infrared CCD) that outputs an electrical signal corresponding to the infrared rays captured by the optical system is used, and the captured image signal is sent to a control means to be described later. The imaging means 7 configured in this way is arranged such that the center of the imaging area is on the same line as the cutting blade 6 in the X-axis direction.

  The front end of the spindle housing 52 is disposed on the same line in the X axis direction as the cutting blade 6 and the image pickup means 7 and detects the height position of the holding surface of the chuck table 36 in the Z axis direction. Position detecting means 8 is provided. The height position detecting means 8 is disposed at a predetermined interval in the X-axis direction and the Y-axis direction (200 mm in the X-axis direction and 0 mm in the Y-axis direction in the illustrated embodiment) from the processing portion by the cutting blade 6. Has been. The height position detection means 8 arranged in this way sends the detected height position signal to the control means described later. As the height position detecting means 8, a back pressure sensor, an interference sensor, a sound wave sensor, a laser sensor, or the like can be used.

  The cutting apparatus in the illustrated embodiment includes a control means 9 as shown in FIG. The control means 9 is constituted by a computer, and a central processing unit (CPU) 91 that performs arithmetic processing according to a control program, a read-only memory (ROM) 92 that stores control programs and the like, and a readable and writable memory that stores arithmetic results and the like. A random access memory (RAM) 93, an input interface 94 and an output interface 95 are provided. The input interface 94 of the control means 9 configured as described above includes a reading head 374b of the X-axis direction position detecting means 374 shown in FIG. 2, a reading head 384b of the Y-axis direction position detecting means 384, and a Z-axis direction position detecting means. Detection signals from 56 reading heads 56b, imaging means 7, height position detecting means 8 and the like are input. From the output interface 95, a pulse motor 340 for rotating the chuck table 36, a pulse motor 372 for the X-axis moving means 37, a pulse motor 382 for the first Y-axis moving means 38, and a second Y-axis moving means 43 are provided. Control signals are output to the pulse motor 432, the pulse motor 552 of the Z-axis moving means 55, and the like. The random access memory (RAM) 93 has an interval in the X-axis direction and the Y-axis direction between the height position detecting means 8 and the machining portion by the cutting blade 6 (in the illustrated embodiment, 200 mm in the X-axis direction, Y A first storage area 93a for storing 0 mm in the axial direction, and a second storage area 93b for storing the Z coordinate value for each XY coordinate value on the holding surface of the chuck table 36 detected by the height position detecting means 8. And other storage areas.

The cutting apparatus in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
Height position detection for detecting the height position in the Z-axis direction of the holding surface which is the upper surface of the suction chuck 361 constituting the chuck table 36 when the above-described cutting apparatus is assembled or when the chuck table 36 is replaced. Perform the process.
In the height position detecting step, first, the X-axis moving unit 37 and the first Y-axis moving unit 38 are operated to position the chuck table 36 in the detection region by the height position detecting unit 8. FIG. 3 shows a state where the suction chuck 361 constituting the chuck table 36 is positioned at a predetermined position. The design value of the suction chuck 361 is stored in a random access memory (RAM) 93 as the XY coordinate values of the outer periphery of the suction chuck 361 constituting the chuck table 36. That is, in the illustrated embodiment, the detection positions in the Y-axis direction are set at 1 mm intervals, and the detection start position coordinate values (A1, A2, A3... An on the outer periphery of the suction chuck 361 in the state of FIG. ) And detection end position coordinate values (B1, B2, B3... Bn) are stored in the random access memory (RAM) 93.

  Next, the control unit 9 operates the X-axis moving unit 37 and the first Y-axis moving unit 38 to position the detection start position coordinate value (A1) of the suction chuck 361 immediately below the height position detecting unit 8. Then, the control means 9 operates the height position detection means 8 and also operates the X-axis movement means 37 to move the chuck table 36 to the detection end position coordinate value (B1) (height position detection step). In this height position detecting step, the height position in the Z-axis direction in the XY coordinate values of the suction chuck 361 is detected every 1 mm based on the signal from the X-axis direction position detecting means 374. The height position detection means 8 sends the detected height position in the Z-axis direction to the control means 9, and the control means 9 detects the height position in the Z-axis direction sent from the height position detection means 8 by the suction chuck 361. The second storage area of the random access memory (RAM) 93 as the height position in the Z-axis direction of the XY coordinate value in 1 mm increments in the X-axis direction from the start position coordinate value (A1) to the detection end position coordinate value (B1) Store in 93b. Thereafter, the height position detection step is performed for each of the detection chuck position 361 of the chuck table 36 from the detection start position coordinate value (A2, A3... An) to the detection end position coordinate value (B2, B3... Bn). The height position in the Z-axis direction at each XY coordinate value is stored in the second storage area 93b of the random access memory (RAM) 93. Then, the chuck table 36 is rotated 90 degrees to detect the height position in the Z-axis direction in the XY coordinate values for each 1 mm in the X-axis direction and the Y-axis direction in the same manner as described above. Is stored in the second storage area 93 b of the random access memory (RAM) 93. In this way, Z-axis direction for each XY coordinate value from all detection start position coordinate values (A1, A2, A3 ... An) to detection end position coordinate values (B1, B2, B3 ... Bn) Of the holding surface, which is the upper surface of the suction chuck 361 constituting the chuck table 36, by detecting the height position of the suction chuck 361 constituting the chuck table 36. Can be determined.

The cutting apparatus in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
FIG. 4 shows a perspective view of a semiconductor wafer as a workpiece. A semiconductor wafer 10 shown in FIG. 4 is made of, for example, a silicon wafer having a thickness of 150 μm, and an IC, LSI, or the like is formed in a plurality of regions partitioned by a plurality of division lines 101 formed in a lattice shape on the surface 10a. A device 102 is formed. The thus formed semiconductor wafer 10 is bonded to the surface 10a side of a protective tape T made of a synthetic resin sheet such as polyolefin and attached to an annular frame F as shown in FIG. Wafer sticking process). Accordingly, the back surface 10b of the semiconductor wafer 10 attached to the protective tape T is on the upper side.

  If the wafer sticking step described above is performed, the protective tape T side of the semiconductor wafer 10 is placed on the chuck table 36 of the cutting apparatus shown in FIG. Then, by operating a suction means (not shown), the semiconductor wafer 10 is sucked and held on the chuck table 36 via the protective tape T (wafer holding step). Therefore, the back surface 100b of the semiconductor wafer 10 held on the chuck table 36 is on the upper side. The annular frame F is fixed by a clamp 362.

  As described above, the chuck table 36 that sucks and holds the semiconductor wafer 10 is positioned directly below the imaging unit by the X-axis moving unit 37. When the chuck table 36 is positioned immediately below the image pickup means in this way, an alignment operation for detecting a processing region to be cut of the semiconductor wafer 10 by the image pickup means and the control means 9 is executed. That is, the image pickup means 7 and the control means 9 are used to align the planned division line 101 formed in a predetermined direction of the semiconductor wafer 10 and the cutting blade 6 that performs cutting along the planned division line 101. Image processing such as pattern matching is performed to align the cutting position. In addition, the alignment of the cutting position is similarly performed on the planned division line 101 formed in the semiconductor wafer 10 and extending in a direction orthogonal to the planned division line 101. At this time, the surface 10a on which the planned division line 110 of the semiconductor wafer 10 is formed is located on the lower side, but the imaging means 7 corresponds to the infrared illumination means, the optical system for capturing infrared rays and the infrared rays as described above. Since an image pickup unit configured with an image pickup device (infrared CCD) or the like that outputs an electric signal is provided, the division planned line 101 can be picked up from the back surface 10b of the semiconductor wafer 10 through the watermark.

  When the alignment for detecting the cutting area of the semiconductor wafer 10 held on the chuck table 36 is performed as described above, the chuck table 51 holding the semiconductor wafer 2 is moved to the cutting work area, and FIG. As shown in FIG. 6A, one end of the predetermined dividing line 101 is positioned slightly to the right in FIG. Next, the cutting blade 6 is rotated in the direction indicated by the arrow 6a, and the Z-axis moving means 55 is operated to cut and feed the cutting blade 6 from the retracted position indicated by the two-dot chain line in the direction indicated by the arrow Z1. The cutting feed position is set such that the outer peripheral edge of the cutting blade 6 is, for example, 10 to 15 μm above the surface 10 a (lower surface) of the semiconductor wafer 10. In the illustrated embodiment, the semiconductor wafer 2 is held on the holding surface which is the upper surface of the suction chuck 361 constituting the chuck table 36 via the protective tape T having a thickness of 100 μm, so that the cutting feed position is at the suction chuck. The position is 110 to 115 μm above the upper surface of 361. When the cutting blade 6 is cut and fed in this way, the chuck table 36 is rotated in the direction shown by the arrow 6a while the cutting blade 6 is rotated in the direction shown by the arrow X1 in FIG. When the other end of the semiconductor wafer 10 is moved at a speed (for example, 50 mm / sec) and the other end of the semiconductor wafer 10 held on the chuck table 36 reaches slightly to the left from directly under the cutting blade 6 as shown in FIG. The movement of 36 is stopped, and the cutting blade 6 is raised to the retracted position indicated by the two-dot chain line in the direction indicated by the arrow Z2. As a result, the semiconductor wafer 10 is cut while leaving a predetermined thickness t (10 to 15 μm in the illustrated embodiment) that does not reach the surface 10a along the predetermined division line 101 as shown in FIG. A groove 110 is formed (a cutting groove forming step).

  In the above-described cutting groove forming step, if there is a undulation on the holding surface, which is the upper surface of the chucking chuck 361 constituting the chuck table 36, the semiconductor wafer 10 sucked and held on the chucking chuck 361 via the protective tape T is undulated. Therefore, even if the cutting blade 6 is intended to be positioned at a desired position (10 to 15 μm in the illustrated embodiment) from the surface 10a (lower surface) of the semiconductor wafer 10, the bottom of the cutting groove 110 is the semiconductor. The surface of the wafer 10 becomes too close or too far away and becomes non-uniform. However, in the cutting apparatus in the illustrated embodiment, as described above, the height position in the Z-axis direction in the XY coordinate values of the holding surface that is the upper surface of the chucking chuck 361 constituting the chuck table 36 is the X-axis direction and the Y-axis. Since the height position in the Z-axis direction at each detected XY coordinate value is stored in the second storage area 93b of the random access memory (RAM) 93, the XY coordinate value is detected. The Z-axis moving means 55 is actuated corresponding to the height position in the Z-axis direction to move the cutting blade 6 in the Z-axis direction. That is, the control means 9 determines the XY coordinate values stored in the second storage area 93b of the random access memory (RAM) 93 based on the detection signals from the X-axis direction position detection means 374 and the Y-axis direction position detection means 384. In the illustrated embodiment, the distance between the height position detecting means 8 stored in the first storage area 93a of the random access memory (RAM) 93 and the machining portion by the cutting blade 6 in the X-axis direction and the Y-axis direction. (In the illustrated embodiment, 200 mm in the X-axis direction and 0 mm in the Y-axis direction) are added and converted to a Z coordinate value corresponding to the XY coordinate value corresponding to the machining portion by the cutting blade 6. And the control means 9 operates the Z-axis movement means 55 based on the Z coordinate value with respect to the converted XY coordinate value, and moves the cutting blade 6 to a Z-axis direction. As a result, a cutting groove 110 is formed in the semiconductor wafer 10 while leaving a predetermined thickness t (10 to 15 μm in the illustrated embodiment) that does not reach the surface 10a along the planned dividing line 101.

  If the above-described cutting groove forming step is performed along all the planned dividing lines 101 formed in the predetermined direction of the semiconductor wafer 10, the chuck table 36 is rotated 90 degrees to form the divided portions formed in the predetermined direction. The cutting groove forming step is executed along the planned division line 101 extending in a direction orthogonal to the planned line 101.

  By performing the above-described cutting groove forming step along all the division lines 101 formed in the semiconductor wafer 10 as described above, the semiconductor wafer 10 has a surface 10a along the all division lines 101. The cutting groove 110 is formed leaving a predetermined thickness t (10 to 15 μm in the illustrated embodiment) that does not reach evenly. Accordingly, when the semiconductor wafer 10 is divided along the cutting grooves 110 by applying an external force to the semiconductor wafer 10 in the next step, the division along each cutting groove 110 becomes uniform and the device quality is stabilized.

  As mentioned above, although the example which implemented this invention to the cutting device was shown, this invention is a processing device which detects and processes the height position of the holding surface which is the upper surface of the chuck table holding a wafer like a laser processing device. Can be applied. By applying the present invention to the laser processing apparatus, even if the holding surface, which is the upper surface of the chuck table, has a slight amount of undulation and the wafer surface is held by the holding surface following the undulation, the laser beam is emitted from the back side of the wafer. When irradiating, it becomes possible to form the modified layer by positioning the condensing point of the laser beam at a desired position from the surface of the wafer, and the position of the modified layer is not too close or too far from the surface. Therefore, in the next wafer dividing step, when an external force is applied to the wafer and the wafer is divided along the modified layer, the division along each modified layer becomes uniform and the device quality is stabilized.

2: stationary base 3: chuck table mechanism 32: first sliding block 33: second sliding block 36: chuck table 37: X-axis moving means 374: X-axis direction position detecting means 38: first Y-axis moving Means 384: Y-axis direction position detecting means 4: Spindle support mechanism 43: Second Y-axis moving means 5: Spindle unit 51: Unit holder 52: Spindle housing 53: Rotating spindle 55: Z-axis moving means 56: Z-axis direction Position detection means 6: Cutting blade 7: Imaging means 8: Height position detection means 9: Control means 10: Semiconductor wafer

Claims (1)

A chuck table having a holding surface for holding the workpiece, a processing means for processing the workpiece held on the holding surface of the chuck table, and the chuck table and the processing means relatively in the X-axis direction. An X-axis moving means that moves, a Y-axis moving means that moves the chuck table and the processing means in a Y-axis direction relatively perpendicular to the X-axis direction, and the processing means that are in the X-axis direction and the Y-axis direction. Z-axis moving means for moving in the orthogonal Z-axis direction, X-axis direction position detecting means for detecting the chuck table moving position by the X-axis moving means, and detecting the chuck table moving position by the Y-axis moving means A processing apparatus comprising: a Y-axis direction position detection means; and a Z-axis direction position detection means for detecting a Z-axis direction position of the processing means by a Z-axis movement means,
A height position detecting means arranged adjacent to the processing means for detecting the height position of the holding surface of the chuck table in the Z-axis direction;
A first storage area for storing an interval in the X-axis direction and the Y-axis direction between the height position detecting means and a processing portion by the processing means; and a holding surface of the chuck table detected by the height position detecting means A control means comprising a memory having a second storage area for storing a Z coordinate value for each XY coordinate value in
The control means converts the XY coordinate values stored in the second storage area of the memory into the first storage area of the memory based on the detection signals from the X-axis direction position detection means and the Y-axis direction position detection means. The stored height position detection means and the distance between the machining part by the machining means and the X-axis direction and the Y-axis direction are added to convert the Z coordinate value to the XY coordinate value corresponding to the machining part by the machining means. , Controlling the Z-axis moving means based on the Z coordinate value for the converted XY coordinate value,
A processing apparatus characterized by that.

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