JP5623795B2 - Processing method of sapphire substrate - Google Patents

Description

  The present invention relates to a method for processing a sapphire substrate that divides a sapphire substrate used as a substrate of an optical device wafer or the like along a predetermined division line.

  In the optical device manufacturing process, an optical device layer made of a gallium nitride compound semiconductor is laminated on the surface of a sapphire substrate having a substantially disc shape, and is divided into a plurality of regions partitioned by a plurality of division lines formed in a lattice shape. An optical device such as a light emitting diode or a laser diode is formed to constitute an optical device wafer. Each optical device is manufactured by dividing the optical device wafer along the planned division line.

  As a dividing method for dividing the above-mentioned optical device wafer along the planned division line, ablation processing is performed by irradiating the sapphire substrate constituting the optical device wafer with a pulsed laser beam having a wavelength that has absorptivity along the planned division line. Thus, there has been proposed a method of cleaving by forming a laser-processed groove serving as a starting point of fracture and applying an external force along a planned division line in which the laser-processed groove serving as a starting point of fracture is formed. (For example, refer to Patent Document 1.)

  However, when a laser processing groove is formed by irradiating a laser beam having an absorptive wavelength to the sapphire substrate along the planned dividing line formed on the surface of the sapphire substrate constituting the optical device wafer, light from a light emitting diode or the like is formed. There is a problem in that a denatured substance generated during laser processing adheres to the side wall surface of the device, the luminance of the optical device is lowered, and the quality of the optical device is lowered.

  Further, the above-described division along the division line of the optical device wafer is performed by a cutting device called a dicer. The cutting apparatus includes a chuck table for holding a workpiece, a cutting means for cutting the workpiece held on the chuck table, and a cutting feed means for relatively moving the chuck table and the cutting means. It has. 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 peripheral portion of the side surface of the base, and the annular cutting edge is based on, for example, diamond abrasive grains having a particle diameter of 3 to 4 μm by nickel plating. It is fixed to a table and has a thickness of 20 to 30 μm. (For example, refer to Patent Document 2.) By cutting the optical device wafer with a cutting blade of such a cutting apparatus, processing is performed without generating a denatured substance on the side wall surface of the optical device as in laser processing. Can do.

JP-A-10-305420 JP 2006-187834 A

  Thus, since the sapphire substrate has a high Mohs hardness, when the cutting groove is formed by a cutting blade, the cutting amount of the cutting blade cannot be increased, and a cutting process is required to form a cutting groove having a predetermined depth. Must be carried out several times. However, when the cutting blade is positioned in the cutting groove after the cutting groove is formed and cutting is performed again, there is a problem that the side surface of the cutting blade comes into contact with the cutting groove and the edge of the cutting groove is chipped.

  The present invention has been made in view of the above-mentioned facts, and the main technical problem thereof is to form a cutting groove having a predetermined depth without causing chipping and to divide the sapphire substrate along a predetermined division line. Another object is to provide a method for processing a sapphire substrate.

In order to solve the main technical problem, according to the present invention, a sapphire substrate processing method for dividing a sapphire substrate along a set division line,
A first cutting blade having a first cutting edge having a first thickness, in which diamond abrasive grains are fixed by nickel plating, is positioned on the division line of the sapphire substrate, and the first cutting blade is rotated while the first cutting blade is rotated. A cutting blade and a sapphire substrate are relatively processed and fed, and a first cutting groove forming step for forming a first cutting groove on the sapphire substrate along a line to be divided;
A second cutting blade having a second cutting blade having a second thickness smaller than the first thickness, in which diamond abrasive grains are fixed by nickel plating, is positioned in the first cutting groove, and the second cutting blade A second cutting groove forming step of forming a second cutting groove on the bottom of the first cutting groove formed on the sapphire substrate by relatively feeding the second cutting blade and the sapphire substrate while rotating When,
An external force is applied to the sapphire substrate on which the first cutting groove forming step and the second cutting groove forming step have been performed, and breaks along the planned division line on which the first cutting groove and the second cutting groove are formed. and breaking step that, only including,
In the first cutting groove forming step and the second cutting groove forming step, the rotational speed of the cutting blade is 20000 to 35000 rpm, the cutting depth of the cutting blade is 5 to 15 μm, and the processing feed speed is 50 to 150 mm / second. Set,
A method for processing a sapphire substrate is provided.

The processing method of the sapphire substrate according to the present invention includes a first cutting groove forming step of forming a first cutting groove on the sapphire substrate along the division line, and a second cutting groove formed on the sapphire substrate at the bottom of the first cutting groove. A second cutting groove forming step for forming a cutting groove, and the second cutting groove forming step includes a thickness of a first annular cutting edge (first cutting means for forming the first cutting groove). Since the second cutting groove is formed at the bottom of the first cutting groove by the second cutting blade having the second annular cutting edge having a thickness (second thickness) smaller than (first thickness), Since the side surface of the second annular cutting edge does not contact the wall surface of the first cutting groove, the edge of the first cutting groove is not chipped.
In the sapphire substrate processing method according to the present invention, the first cutting groove forming step and the second cutting groove forming step have a cutting blade rotational speed of 20000 to 35000 rpm and a cutting blade cutting depth of 5 to 15 μm. Since the processing feed rate is set to 50 to 150 mm / sec, the sapphire substrate is not chipped, and the cutting blade constituting the cutting blade is not damaged, and the amount of wear of the cutting blade is reduced. At the same time, productivity can be improved. In particular, in the method for processing a sapphire substrate according to the present invention, the processing feed rate is set to 50 to 150 mm / sec. It is possible to process at a processing speed of ˜50 times and improve productivity, and the amount of wear of the cutting blade can be reduced to ½ or less, and the replacement frequency of the cutting blade can be reduced to ½ or less. .

The perspective view and principal part expanded sectional view which show the optical device wafer processed according to the processing method of the sapphire substrate by this invention. Explanatory drawing of the wafer support process in the processing method of the sapphire substrate by this invention. The principal part perspective view of the cutting device for enforcing the 1st cutting groove formation process in the processing method of the sapphire substrate by this invention. Sectional drawing of the cutting blade with which the cutting apparatus shown in FIG. 3 is equipped. Explanatory drawing of the 1st cutting groove formation process in the processing method of the sapphire substrate by this invention. Sectional drawing which expands and shows the principal part of the optical device wafer in which the 1st cutting groove formation process in the processing method of the sapphire substrate by this invention was implemented. The principal part perspective view of the cutting device for implementing the 2nd cutting groove formation process in the processing method of the sapphire substrate by this invention. Explanatory drawing of the 2nd cutting groove formation process in the processing method of the sapphire substrate by this invention. Sectional drawing which expands and shows the principal part of the optical device wafer in which the 2nd cutting groove formation process in the processing method of the sapphire substrate by this invention was implemented. The perspective view of the wafer fracture | rupture apparatus for implementing the fracture | rupture process in the processing method of the sapphire substrate by this invention. Explanatory drawing of the fracture | rupture process in the processing method of the sapphire substrate by this invention.

  Hereinafter, a preferred embodiment of a method for processing a sapphire substrate according to the present invention will be described in detail with reference to the accompanying drawings.

  1A and 1B show a perspective view of an optical device wafer processed according to the method for processing a sapphire substrate according to the present invention and a sectional view showing an enlarged main part. An optical device wafer 2 shown in FIGS. 1A and 1B has a light emitting layer (epilayer) 21 as an optical device layer made of a nitride semiconductor on a surface 20a of a sapphire substrate 20 having a thickness of 100 μm, for example. It is laminated by thickness. An optical device 23 such as a light emitting diode or a laser diode is formed in a plurality of regions partitioned by a plurality of division lines 22 in which the light emitting layer (epi layer) 21 is formed in a lattice shape. Hereinafter, a processing method for dividing the optical device wafer 2 into the individual optical devices 23 along the planned division line 22 will be described.

  In the sapphire substrate processing method according to the present invention, first, as shown in FIGS. 2A and 2B, a dicing tape in which the back surface 20b of the sapphire substrate 20 constituting the optical device wafer 2 is mounted on the annular frame 3 is used. Adhering to the surface of 4 (wafer support step).

  When the wafer supporting step described above is performed, the first cutting blade having the first cutting edge having the first thickness in which the diamond abrasive grains are fixed by nickel plating is divided into the optical device wafer 2 made of a sapphire substrate. The first cutting blade and the sapphire substrate are moved relative to each other while the first cutting blade is rotated and the first cutting blade is rotated to form a first cutting groove along the division planned line. A 1st cutting groove formation process is implemented. This first cutting groove forming step is performed by using the cutting device 5 shown in FIG. 3 in the illustrated embodiment. 3 includes a chuck table 51 that holds a workpiece, a cutting means 52 that cuts the workpiece held on the chuck table 51, and a workpiece held on the chuck table 51. The image pickup means 53 for picking up images is provided. The chuck table 51 is configured to suck and hold a workpiece. The chuck table 51 is moved in a machining feed direction indicated by an arrow X in FIG. 3 by a cutting feed means (not shown) and is indicated by an arrow Y by an index feed means (not shown). It can be moved in the index feed direction shown.

  The cutting means 52 includes a spindle housing 521 arranged substantially horizontally, a rotating spindle 522 rotatably supported by the spindle housing 521, and a first cutting blade mounted on the tip of the rotating spindle 522. Rotation spindle 522 is rotated in the direction indicated by arrow A by a servo motor (not shown) disposed in spindle housing 521. As shown in FIG. 4, the first cutting blade 523 includes a base 524 and a first annular cutting edge 525 attached to the outer peripheral portion of the side surface of the base 524. The first annular cutting edge 525 is composed of an electroformed blade in which diamond abrasive grains having a particle diameter of 3 to 4 μm are hardened by nickel plating on the outer peripheral portion of the side surface of the base 524, and has a thickness (first thickness). The outer diameter is 30 mm and the outer diameter is 52 mm.

  The imaging means 53 is attached to the tip of the spindle housing 521, and illuminates the work piece, an optical system that captures an area illuminated by the illumination means, and an image captured by the optical system. An image pickup device (CCD) or the like for picking up images is provided, and the picked up image signal is sent to a control means (not shown).

  In order to perform the first cutting groove forming step using the cutting device 5 described above, the back surface 20b of the sapphire substrate 20 constituting the optical device wafer 2 was stuck on the chuck table 51 as shown in FIG. The optical device wafer 2 is sucked and held on the chuck table 51 via the dicing tape 4 by placing the dicing tape 4 side and operating a suction means (not shown) (wafer holding step). Therefore, the surface 2a of the optical device wafer 2 held on the chuck table 51 is on the upper side. In FIG. 3, the annular frame 3 on which the dicing tape 4 is mounted is omitted, but the annular frame 3 is fixed by a clamp mechanism disposed on the chuck table 51. In this way, the chuck table 51 that sucks and holds the optical device wafer 2 is positioned directly below the imaging means 53 by a cutting feed means (not shown).

  When the chuck table 51 is positioned immediately below the image pickup means 53, an alignment operation for detecting a region to be processed of the optical device wafer 2 is executed by the image pickup means 53 and a control means (not shown). That is, the imaging unit 53 and a control unit (not shown) perform alignment for aligning the planned dividing line 22 formed in the predetermined direction on the surface 2a of the optical device wafer 2 and the first cutting blade 523. (Alignment process). In addition, the alignment of the processing region is performed in the same manner for the division lines 22 formed on the surface 2a of the optical device wafer 2 in a direction orthogonal to the predetermined direction.

  If the alignment for detecting the processing region of the optical device wafer 2 held on the chuck table 51 is performed as described above, the chuck table 51 holding the optical device wafer 2 by suction is held by the first cutting blade 523. It moves to the processing start position of the processing area below. Then, as shown in FIG. 5 (a), one end (the left end in FIG. 5 (a)) of the planned dividing line 22 to be processed of the optical device wafer 2 is on the right side by a predetermined amount from directly below the first cutting blade 523. Position so as to be positioned (process feed start position positioning step). When the optical device wafer 2 is thus positioned at the machining start position in the machining area, the first cutting blade 523 is rotated in the direction indicated by the arrow A, and is indicated by a two-dot chain line in FIG. It cuts and feeds downward from the standby position, and is positioned at a predetermined cutting and feeding position as shown by a solid line in FIG. As shown in FIGS. 5A and 6A, the cutting feed position is such that the lower end of the outer peripheral edge of the first annular cutting edge 525 constituting the first cutting blade 523 is the optical device wafer 2. For example, it is set at a position 15 μm below the surface 2a (upper surface). If the cutting depth is deeper than 15 μm, the load applied to the cutting blade increases, and chipping and cracking occur on the upper surface of the sapphire substrate, so the cutting depth is limited to 15 μm. On the other hand, when the cutting depth is less than 5 μm, the load applied to the cutting blade is small, but the productivity is poor because it is necessary to cut a plurality of times to form a cutting groove having a predetermined depth. Therefore, it is desirable to set the cutting depth of the cutting blade to 5 to 15 μm. In the illustrated embodiment, the cutting depth of the cutting blade is set to 15 μm.

  Next, as shown in FIG. 5 (a), the first cutting blade 523 is rotated at a predetermined rotational speed in the direction indicated by the arrow A, while the chuck table 51 is indicated by the arrow X1 in FIG. 5 (a). Processing feed is performed in a direction at a predetermined processing feed speed (first cutting groove forming step). As a result, as shown in FIG. 5B and FIG. 6B, the optical device wafer 2 has a first width of 30 μm and a depth of 15 μm as the break starting point along the division line 22. A cutting groove 201 is formed. In the first cutting groove forming step, it is desirable to set the rotational speed of the cutting blade to 20000 to 35000 rpm and the processing feed speed to 50 to 150 mm / sec. If the rotation speed of the cutting blade is less than 20000 rpm, the cutting blade is likely to be damaged. On the other hand, if the rotation speed of the cutting blade exceeds 35000 rpm, the cutting blade is blurred and the sapphire substrate is chipped. As for the machining feed rate, according to the experiments by the present inventors, when the cutting groove having a predetermined length is formed, the lower the machining feed rate, the larger the wear amount of the annular cutting edge constituting the cutting blade. It was found that the higher the machining feed rate, the smaller the wear amount of the annular cutting edge constituting the cutting blade. Hereinafter, experimental examples of the inventors will be described.

Experimental example

The sapphire substrate was cut using a cutting blade having a cutting edge formed of an electroformed blade formed by solidifying nickel abrasive grains having a particle diameter of 3 to 4 μm with nickel plating and having a thickness of 30 μm and an outer diameter of 52 mm. The machining conditions at this time were a cutting depth of 15 μm, a cutting blade rotation speed of 30000 rpm, and a machining feed rate of 1 to 150 mm / sec, each of which was cut by 1 m.
As a result of this experiment, the following results were obtained.
(1) When the machining feed rate is 1 mm / second, the wear amount of the cutting blade constituting the cutting blade is 7 μm.
/ Processing length 1m.
(2) When the machining feed rate is 3 mm / second, the wear amount of the cutting blade constituting the cutting blade is 6 μm.
/ Processing length 1m.
(3) When the processing feed rate is 10 mm / second, the wear amount of the cutting blade constituting the cutting blade is 5 μm.
m / processing length 1m.
(4) When the processing feed rate is 30 mm / second, the wear amount of the cutting blade constituting the cutting blade is 4 μm.
m / processing length 1m.
(5) When the machining feed rate is 50 mm / second, the amount of wear of the cutting edge constituting the cutting blade is 2.
5 μm / processing length 1 m.
(6) When the machining feed rate is 100 mm / second, the wear amount of the cutting blade constituting the cutting blade is 2
μm / processing length 1m.
(7) When the machining feed rate is 150 mm / sec, the wear amount of the cutting blade constituting the cutting blade is 1
. 8μm / processing length 1m.
(8) When the machining feed rate is 160 mm / sec, the wear amount of the cutting blade constituting the cutting blade is 1
. 8μm / processing length 1m. However, chipping occurs in the sapphire substrate.

  From the above experimental results, it can be seen that the lower the machining feed rate, the greater the wear amount of the cutting blade constituting the cutting blade, and the faster the machining feed rate, the smaller the wear amount of the cutting blade constituting the cutting blade. In particular, when the processing feed rate is 50 mm / second, the wear amount of the cutting blade constituting the cutting blade is 2.5 μm / processing length 1 m, and the processing feed rate (3 mm / second), which has been commonly used in cutting sapphire substrates in the past. The amount of wear is 42% compared to the case of the second), and the life of the cutting blade is improved more than twice. When the machining feed rate is set to 150 mm / second, the wear amount of the cutting blade constituting the cutting blade is 1.8 μm / working length 1 m, and the machining feed rate (3 mm / mm), which has been commonly used in the cutting of sapphire substrates in the past. The amount of wear is 30% and the life of the cutting blade is more than tripled. On the other hand, when the processing feed rate exceeds 150 mm / sec and reaches 160 mm / sec, chipping occurs in the sapphire substrate.

  As described above, by setting the machining feed rate to 50 to 150 mm / second, the cutting blade is configured as compared with the case of the machining feed rate (3 mm / second) that has been common knowledge in the cutting of sapphire substrates. Since the wear amount of the cutting edge is ½ or less, the replacement frequency of the cutting blade can be reduced to ½ or less, which is economical. In addition, by setting the processing feed rate to 50 to 150 mm / sec, the sapphire substrate is not chipped or the cutting blades constituting the cutting blade are not damaged, and it has been common knowledge in conventional sapphire substrate cutting. Processing can be performed at a processing speed 15 to 50 times the processing feed rate (3 mm / sec), and productivity can be improved.

  As described above, when the first cutting groove forming step is performed along all the division lines 22 extending in a predetermined direction of the optical device wafer 2, the chuck table 51 is rotated 90 degrees. Then, the first cutting groove forming step is performed along each division line 22 formed in a direction orthogonal to the predetermined direction.

  If the 1st cutting groove formation process mentioned above was implemented, the 2nd cutting blade provided with the 2nd cutting blade which has the 2nd thickness smaller than the 1st thickness which fixed the diamond abrasive grain by nickel plating. Positioned in the first cutting groove 201, the second cutting blade and the sapphire substrate are relatively processed and fed while rotating the second cutting blade, and the bottom of the first cutting groove 201 formed in the optical device wafer 2 A second cutting groove forming step for forming a second cutting groove is performed. This 2nd cutting groove formation process is implemented using the cutting device 50 shown in FIG. 7 is the same as that shown in FIG. 3 except that the second blade 523a constituting the cutting means 52 is different from the first blade 523 constituting the cutting means 52 of the cutting apparatus 5 shown in FIG. Therefore, the same members are denoted by the same reference numerals, and the description thereof is omitted. That is, in the second blade 523a constituting the cutting means 52 of the cutting device 50 shown in FIG. 7, the thickness (second thickness) of the second annular cutting edge 525a constitutes the first blade 523. It is formed to be 20 μm smaller than the thickness (first thickness) of one annular cutting edge 525.

  In order to perform the second cutting groove forming step using the cutting apparatus 50 described above, the optical device wafer 2 in which the first cutting groove forming step is performed on the chuck table 51 as shown in FIG. The optical device wafer 2 is sucked and held on the chuck table 51 via the dicing tape 4 by placing the dicing tape 4 side to which the back surface 20b of the sapphire substrate 20 is stuck and operating a suction means (not shown). Wafer holding process). Therefore, the surface 2a of the optical device wafer 2 held on the chuck table 51 is on the upper side. In FIG. 7, the annular frame 3 to which the dicing tape 4 is mounted is omitted, but the annular frame 3 is fixed by a clamp mechanism disposed on the chuck table 51. In this way, the chuck table 51 that sucks and holds the optical device wafer 2 is positioned directly below the imaging means 53 by a cutting feed means (not shown).

  When the chuck table 51 is positioned immediately below the image pickup means 53, an alignment operation for detecting a region to be processed of the optical device wafer 2 is executed by the image pickup means 53 and a control means (not shown). That is, the image pickup means 53 and the control means (not shown) are configured so that the first cutting groove 201 and the second cutting blade 523a formed along the planned division line 22 formed in the predetermined direction on the surface 2a of the optical device wafer 2. Alignment is performed for alignment with (alignment process). Similarly, the alignment of the processing region is also performed on the first cutting groove 201 formed along the division line 22 formed on the surface 2a of the optical device wafer 2 in a direction orthogonal to the predetermined direction. Is carried out.

  If the alignment for detecting the processing region of the optical device wafer 2 held on the chuck table 51 is performed as described above, the chuck table 51 holding the optical device wafer 2 by suction is held by the second cutting blade 523a. It moves to the processing start position of the processing area below. Then, as shown in FIG. 8A, one end (the left end in FIG. 8A) of the first cutting groove 201 formed along the division line 22 to be processed of the optical device wafer 2 is the first. 2 is positioned so as to be located a predetermined amount to the right of directly below the cutting blade 523a (processing feed start position positioning step). At this time, the second cutting blade 523a is positioned so as to be positioned at the center in the width direction of the first cutting groove 201. When the optical device wafer 2 is positioned at the machining start position of the machining area in this way, the second cutting blade 523a is rotated in the direction indicated by the arrow A and is indicated by a two-dot chain line in FIG. It cuts and feeds downward from the standby position, and is positioned at a predetermined cutting and feeding position as shown by a solid line in FIG. As shown in FIGS. 8A and 9A, the cutting feed position is such that the lower end of the outer peripheral edge of the second annular cutting edge 525a constituting the second cutting blade 523a is the optical device wafer 2. For example, a position 30 μm below the surface 2 a (upper surface) of the sapphire substrate 20 (a position 15 μm below the bottom surface of the first cutting groove 201).

  Next, as shown in FIG. 8A, the chuck table 51 is indicated by an arrow X1 in FIG. 8A while the second cutting blade 523a is rotated at a predetermined rotational speed in the direction indicated by the arrow A. Processing feed in the direction at a predetermined processing feed speed (second cutting groove forming step). As a result, as shown in FIGS. 8B and 9B, the optical device wafer 2 has a depth of 15 μm from the bottom of the first cutting groove 201 and is narrower than the second cutting groove 201. A second cutting groove 202 having a width (20 μm) is formed. The processing conditions in the second cutting groove forming step may be the same as the processing conditions in the first cutting groove forming step.

  As described above, in the second cutting groove forming step, the thickness (first thickness: 30 μm) of the first annular cutting edge 525 that constitutes the first cutting blade 523 that forms the first cutting groove 201. The second cutting groove 202 is first formed at the bottom of the cutting groove 201 by the second cutting blade 523a having the second annular cutting edge 525a having a smaller thickness (second thickness: 20 μm). Since the side surface of the second annular cutting edge 525a does not first contact the wall surface of the cutting groove 201, first, the edge of the cutting groove 201 is not chipped.

  As described above, if the first cutting groove forming step and the second cutting groove forming step are performed, an external force is applied to the optical device wafer, and the first cutting groove 201 and the second cutting groove serving as a breakage starting point. A rupturing step is performed in which the rupture is performed along the planned dividing line 202. This breaking step is performed using a wafer breaking device 6 shown in FIG. The wafer breaking device 6 shown in FIG. 10 includes a base 61 and a moving table 62 disposed on the base 61 so as to be movable in the direction indicated by the arrow Y. The base 61 is formed in a rectangular shape, and two guide rails 611 and 612 are arranged in parallel to each other in the direction indicated by the arrow Y on the upper surface of both side portions. A moving table 62 is movably disposed on the two guide rails 611 and 612. The moving table 62 is moved in the direction indicated by the arrow Y by the moving means 63. Frame holding means 64 for holding the annular frame 3 is disposed on the moving table 62. The frame holding means 64 includes a cylindrical main body 641, an annular frame holding member 642 provided at the upper end of the main body 641, and a plurality of clamps 643 as fixing means disposed on the outer periphery of the frame holding member 642. It is made up of. The frame holding means 64 configured as described above fixes the annular frame 3 placed on the frame holding member 642 by the clamp 643. Further, the wafer breaking device 6 shown in FIG. 10 includes a turning means 65 for turning the frame holding means 64. The rotating means 65 is wound around a pulse motor 651 disposed on the moving table 62, a pulley 652 mounted on the rotation shaft of the pulse motor 651, and the pulley 652 and a cylindrical main body 641. It consists of an endless belt 653. The rotation means 65 configured as described above rotates the frame holding means 64 via the pulley 652 and the endless belt 653 by driving the pulse motor 651.

  The wafer breaking device 6 shown in FIG. 10 is arranged in a direction perpendicular to the division line 22 on the optical device wafer 2 supported by the annular frame 3 held by the annular frame holding member 642 via the dicing tape 4. A tension applying means 66 for applying a tensile force is provided. The tension applying means 66 is disposed in the annular frame holding member 642. The tension applying means 66 includes a first suction holding member 661 and a second suction holding member 662 each having a rectangular holding surface that is long in a direction orthogonal to the arrow Y direction. The first suction holding member 661 has a plurality of suction holes 661a, and the second suction holding member 662 has a plurality of suction holes 662a. The plurality of suction holes 661a and 662a communicate with suction means (not shown). Further, the first suction holding member 661 and the second suction holding member 662 can be moved in the arrow Y direction by a moving means (not shown).

  The wafer breaking device 6 shown in FIG. 10 detects the division line 22 of the optical device wafer 2 supported by the annular frame 3 held by the annular frame holding member 642 via the dicing tape 4. Detection means 67 is provided. The detection means 67 is attached to an L-shaped support column 671 disposed on the base 61. The detection means 67 is composed of an optical system, an image pickup device (CCD), and the like, and is disposed above the tension applying means 66. The detection means 67 configured in this way images the division line 22 of the optical device wafer 2 supported by the annular frame 3 held by the annular frame holding member 642 via the dicing tape 4, This is converted into an electrical signal and sent to a control means (not shown).

A wafer dividing process performed using the wafer breaker 6 described above will be described with reference to FIG.
The annular frame 3 that supports the optical device wafer 2 on which the above-described cutting groove forming step has been performed via the dicing tape 4 is placed on the frame holding member 642 as shown in FIG. 643 is fixed to the frame holding member 642. Next, the moving means 63 is actuated to move the moving table 62 in the direction indicated by the arrow Y (see FIG. 10), and 1 formed on the optical device wafer 2 in a predetermined direction as shown in FIG. The scheduled dividing line 22 (the leftmost scheduled dividing line in the illustrated embodiment) is the holding surface of the first suction holding member 661 and the holding surface of the second suction holding member 662 constituting the tension applying means 66. Position between. At this time, the dividing line 22 is imaged by the detection means 67, and the holding surface of the first suction holding member 661 and the holding surface of the second suction holding member 662 are aligned. In this way, when one division planned line 22 is positioned between the holding surface of the first suction holding member 661 and the holding surface of the second suction holding member 662, the suction means (not shown) is operated. Then, by applying a negative pressure to the suction holes 661a and 662a, the optical device wafer 2 is sucked through the dicing tape 4 onto the holding surface of the first suction holding member 661 and the holding surface of the second suction holding member 662. Hold (holding step).

  When the holding step described above is performed, the moving means (not shown) constituting the tension applying means 66 is operated, and the first suction holding member 661 and the second suction holding member 662 are shown in FIG. Move them away from each other. As a result, the planned dividing line 22 positioned between the holding surface of the first suction holding member 661 and the holding surface of the second suction holding member 662 has a tensile force in a direction perpendicular to the planned dividing line 22. As a result, the optical device wafer 2 is broken along the planned dividing line 22 with the first cutting groove 201 and the second cutting groove 202 as the starting point of the break (breaking step). By carrying out this breaking process, the dicing tape 4 slightly extends. In this breaking process, since the optical device wafer 2 is formed with the first cutting groove 201 and the second cutting groove 202 along the planned dividing line 22 to reduce the strength, the first suction holding member 661 is used. And the second suction holding member 662 are moved about 0.5 mm away from each other, whereby the first cutting groove 201 and the second cutting groove 202 formed in the sapphire substrate 20 are broken in the optical device wafer 2. It can be broken along the planned dividing line 22.

  As described above, if the breaking process of breaking along one division planned line 22 formed in a predetermined direction is performed, the optical device by the first suction holding member 661 and the second suction holding member 662 described above. Release the suction hold of the wafer 2. Next, the moving means 63 is actuated to move the moving table 62 in the direction indicated by the arrow Y (see FIG. 10) by an amount corresponding to the interval between the scheduled division lines 22 and The adjacent division line 22 is positioned between the holding surface of the first suction holding member 661 and the holding surface of the second suction holding member 662 constituting the tension applying means 66. And the said holding process and a fracture | rupture process are implemented.

  As described above, when the holding step and the breaking step are carried out for all the planned dividing lines 22 formed in the predetermined direction, the turning means 65 is operated to turn the frame holding means 64 by 90 degrees. Let me. As a result, the optical device wafer 2 held by the frame holding member 642 of the frame holding means 64 is also rotated 90 degrees, and the direction perpendicular to the planned dividing line 22 formed in a predetermined direction and subjected to the above-described breaking process is performed. The division lines 22 formed in the first and second suction holding members 661 are positioned in a state parallel to the holding surface of the first suction holding member 661 and the holding surface of the second suction holding member 662. Next, the optical device wafer 2 is divided by performing the above-described holding process and breaking process on all the planned dividing lines 22 formed in a direction orthogonal to the planned dividing line 22 in which the breaking process is performed. Divided into individual devices 23 along the planned line 22.

Although the present invention has been described based on the illustrated embodiment, the present invention is not limited to the embodiment, and various modifications are possible within the scope of the gist of the present invention. For example, in the above-described embodiment, the example in which the first cutting groove forming step and the second cutting groove forming step are performed by separate cutting devices has been described. However, the cutting means including the first cutting blade and the first cutting groove forming step You may implement a 1st cutting groove formation process and a 2nd cutting groove formation process with the cutting device provided with the cutting means provided with 2 cutting blades.

2: Optical device wafer 20: Sapphire substrate 21: Light emitting layer (epi layer) as an optical device layer
3: annular frame 4: dicing tape 5: cutting device 51: chuck table of cutting device 52: cutting means 523: first cutting blade 523a: second cutting blade 6: wafer breaking device 62: moving table 63: moving Means 64: Frame holding means 65: Rotating means 66: Tension applying means 67: Detection means

Claims (1)

A sapphire substrate processing method for dividing a sapphire substrate along a set division line,
A first cutting blade having a first cutting edge having a first thickness, in which diamond abrasive grains are fixed by nickel plating, is positioned on the division line of the sapphire substrate, and the first cutting blade is rotated while the first cutting blade is rotated. A cutting blade and a sapphire substrate are relatively processed and fed, and a first cutting groove forming step for forming a first cutting groove on the sapphire substrate along a line to be divided;
A second cutting blade provided with a second cutting blade having a second thickness smaller than the first thickness, in which diamond abrasive grains are fixed to the division line of the sapphire substrate by nickel plating, is used as the first cutting groove. Positioning and rotating the second cutting blade, the second cutting blade and the sapphire substrate are relatively processed and fed to form a second cutting groove at the bottom of the first cutting groove formed in the sapphire substrate. A second cutting groove forming step;
An external force is applied to the sapphire substrate on which the first cutting groove forming step and the second cutting groove forming step have been performed, and breaks along the planned division line on which the first cutting groove and the second cutting groove are formed. and breaking step that, only including,
In the first cutting groove forming step and the second cutting groove forming step, the rotational speed of the cutting blade is 20000 to 35000 rpm, the cutting depth of the cutting blade is 5 to 15 μm, and the processing feed speed is 50 to 150 mm / second. Set,
A method for processing a sapphire substrate.

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