JP5735217B2 - Method and apparatus for grinding hard substrate - Google Patents

Description

  The present invention relates to a grinding method and a grinding apparatus for a hard substrate such as a sapphire substrate which is a substrate for an optical device wafer or the like.

  In the optical device manufacturing process, an optical device layer made of a gallium nitride compound semiconductor is laminated on the surface of a substantially disc-shaped sapphire substrate or silicon carbide substrate, and is partitioned by a plurality of streets formed in a lattice shape. Optical devices such as light emitting diodes and laser diodes are formed in the region to constitute an optical device wafer. The optical device wafer thus configured is cut along the streets to divide the region where the optical device is formed to manufacture individual optical devices.

  The optical device wafer divided in this way is used to grind the back surface of the sapphire substrate or silicon carbide substrate before cutting along the street in order to reduce the weight, size and brightness of the optical device. And processed to a predetermined thickness. A grinding apparatus for grinding a back surface of a sapphire substrate or a silicon carbide substrate includes a chuck table having a holding surface for holding a workpiece and a grinding wheel for grinding a wafer held on the holding surface of the chuck table. A grinding means provided with a driving source such as a grinding wheel and a servo motor for rotationally driving the grinding wheel, and a grinding feed means for grinding and feeding the grinding means in a direction perpendicular to the holding surface of the chuck table. The workpiece is ground to a predetermined thickness by rotating the grinding wheel while bringing the grinding surface of the grinding wheel into contact with the surface to be ground of the workpiece and grinding and feeding at a predetermined grinding feed speed. (For example, refer to Patent Document 1.)

JP 2008-23893 A

  Thus, since the sapphire substrate and silicon carbide substrate constituting the optical device wafer have high hardness and the back surface is formed in a mirror surface, grinding is performed even when grinding with a grinding wheel composed mainly of diamond abrasive grains. Is difficult. In other words, because the abrasive grains of the grinding wheel that finishes the sapphire substrate, which is the workpiece, to a predetermined thickness, have a small particle size, the so-called bite into the substrate is weak and slips, and the pressing force increases with grinding feed and damages the substrate There is a problem of making it.

  The present invention has been made in view of the above-mentioned facts, and the main technical problem is that even a hard substrate such as a sapphire substrate or a silicon carbide substrate is damaged by preventing the occurrence of slippage by improving the so-called biting by the grinding wheel. An object of the present invention is to provide a grinding method and a grinding apparatus for a hard substrate that can be formed to a predetermined thickness without causing them.

In order to solve the above main technical problem, according to the present invention, there is provided a grinding method for a hard substrate that forms a predetermined thickness by grinding a work surface of a hard substrate,
A matte processing step in which a grinding wheel is brought into contact with the processing surface of the hard substrate and rotated at different rotation speeds to scratch the processing surface of the hard substrate and form on the matte surface;
The processed surface of the rigid substrate該梨land processing step is performed by grinding the configured grinding wheel as the main component of diamond abrasive grains, seen including and a grinding step for grinding to a predetermined thickness,
The satin finish processing step is performed by a grinding wheel composed mainly of diamond abrasive grains having a particle size of 500 to 1000 μm, and the grinding step is grinding composed mainly of diamond abrasive grains having a particle size of 10 to 50 μm. Carried out with a grinding wheel,
A method for grinding a hard substrate is provided.

According to the present invention, a chuck table having a holding surface for holding a workpiece, a grinding wheel having a grinding wheel for grinding the workpiece held on the holding surface of the chuck table, and the grinding wheel Grinding means having a drive source for rotationally driving the grinding wheel, grinding feed means for grinding and feeding the grinding means in a direction perpendicular to the holding surface of the chuck table, and the chuck table by the grinding means In a grinding apparatus comprising a grinding table and a chuck table positioning means positioned in a non-grinding region retracted from the grinding region,
In the non-grinding area, a matte finishing means provided with a satin processing tool for scratching the workpiece surface of the workpiece held on the chuck table and forming it on the matte ground is disposed,
The satin processing tool is provided with a grinding wheel composed mainly of diamond abrasive grains having a particle size of 500 to 1000 μm so as to come into contact with the processing surface of the workpiece and be rotated at a rotation speed different from that of the chuck table. Configured,
The grinding wheel includes a grinding wheel composed mainly of diamond abrasive grains having a particle size of 10 to 50 μm.
A grinding device is provided.

In the method for grinding a hard substrate according to the present invention, the surface of the hard substrate is formed on the ground surface by scratching the surface to be processed of the hard substrate by bringing the grinding wheel into contact with the surface of the hard substrate and rotating the grindstone at different rotational speeds. process and to ground by configured grinding wheel to be processed surface of the rigid substrate satin finish process is carried out as the main component of diamond abrasive grains, seen including a grinding step for grinding to a predetermined thickness, satin finish step Since the grinding is performed with a grinding wheel composed mainly of diamond abrasive grains having a particle size of 500 to 1000 μm, and the grinding step is performed with a grinding wheel composed mainly of diamond abrasive grains having a particle diameter of 10 to 50 μm, When grinding with a grinding wheel, the work surface of the hard substrate is formed on a satin surface, so that the so-called biting by the grinding wheel is good and grinding starts. Both grinding progresses. Therefore, the problem that the hard substrate is damaged can be solved by increasing the pressing force of the grinding wheel by sliding grinding feed on the processing surface of the hard substrate.

A grinding device according to the present invention includes a chuck table having a holding surface for holding a workpiece, a grinding wheel having a grinding wheel for grinding the workpiece held on the holding surface of the chuck table, and Grinding means having a drive source for rotationally driving the grinding wheel, grinding feed means for grinding and feeding the grinding means in a direction perpendicular to the holding surface of the chuck table, and a grinding area by the grinding means A satin surface for forming a ground surface by scratching a work surface of a work piece held by the chuck table in the non-grinding region and having a chuck table positioning means positioned in a non-grinding region retracted from the grinding region processing is disposed a satin finish means having a tool, satin finish tool, configured as a main component diamond abrasive grains having a grain size is 500~1000μm The grinding wheel is configured to come into contact with the work surface of the work piece and to be rotated at a rotation speed different from that of the chuck table, and the grinding wheel has diamond abrasive grains having a particle size of 10 to 50 μm as a main component. Since it is equipped with a configured grinding wheel, the surface of the workpiece that has been subjected to the matte finishing process is formed on the matte surface by scratching the workpiece surface of the workpiece with the grinding wheel. And a grinding process of grinding to a predetermined thickness with a grinding wheel can be carried out by a single grinding apparatus.

1 is a perspective view of a grinding apparatus constructed according to the present invention. The perspective view of the grinding wheel which comprises the grinding unit with which the grinding apparatus shown in FIG. 1 is equipped. The perspective view which shows the chuck table mechanism and chuck table positioning means with which the grinding apparatus shown in FIG. 1 is equipped. FIG. 2 is a perspective view of a satin processing tool that constitutes a satin processing unit equipped in the grinding apparatus shown in FIG. 1. FIG. 2 is a perspective view of an optical device wafer processed by the grinding apparatus shown in FIG. Explanatory drawing which shows the protection member sticking process which sticks a protection member on the surface of the optical device wafer shown in FIG. Explanatory drawing of the satin finishing process in this invention implemented with the grinding apparatus shown in FIG. The perspective view of the optical device wafer in which the satin processing process shown in FIG. 7 was implemented. Explanatory drawing of the grinding process in this invention implemented with the grinding apparatus shown in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a method and apparatus for grinding a hard substrate according to the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 shows a perspective view of a grinding apparatus constructed in accordance with the present invention.
The grinding apparatus shown in FIG. 1 is provided with an apparatus housing generally indicated by numeral 2. The apparatus housing 2 has a rectangular parallelepiped main portion 21 that extends elongated and an upright wall 22 that is provided at the rear end portion (upper right end in FIG. 1) of the main portion 21 and extends upward. A pair of guide rails 221 and 221 extending in the vertical direction are provided on the front surface of the upright wall 22. A grinding unit 3 as grinding means is mounted on the pair of guide rails 221 and 221 so as to be movable in the vertical direction.

  The grinding unit 3 includes a moving base 31 and a spindle unit 32 attached to the moving base 31. The movable base 31 is provided with a pair of legs 311 and 311 extending in the vertical direction on both sides of the rear surface. The pair of legs 311 and 311 is slidably engaged with the pair of guide rails 221 and 221. Guided grooves 312 and 312 are formed. As described above, a support portion 313 protruding forward is provided on the front surface of the movable base 31 slidably mounted on the pair of guide rails 221 and 221 provided on the upright wall 22. The spindle unit 32 is attached to the support portion 313.

  The spindle unit 32 includes a spindle housing 321 mounted on the support portion 313, a rotary spindle 322 rotatably disposed on the spindle housing 321, and a servo motor as a drive source for rotationally driving the rotary spindle 322. 323. The lower end of the rotary spindle 322 protrudes downward beyond the lower end of the spindle housing 321, and a mounter 324 is provided at the lower end. A grinding wheel 325 is attached to the lower surface of the mounter 324. As shown in FIG. 2, the grinding wheel 325 includes an annular base 326 and a grinding wheel 327 annularly attached to the lower surface of the base 326, and the annular base 326 is attached to the mounter 324 with a fastening bolt 328. Installed by. In the illustrated embodiment, the grinding wheel 327 is formed by bonding diamond abrasive grains having a particle size of 10 to 50 μm with vitrified bonds, and the lower surface forms a grinding surface 327a.

  Referring back to FIG. 1, the description will be continued. A grinding water supply passage 322 a is formed in the rotary spindle 322, and this grinding water supply passage 322 a is connected to the grinding water supply means 320. Therefore, when the grinding water supply means 320 is operated, the grinding water is supplied to the grinding wheel 327 constituting the grinding wheel 325 through the grinding water supply passage 322a and the grinding water supply hole (not shown) provided in the mounter 324.

  The illustrated grinding apparatus includes grinding feed means 4 for moving the grinding unit 3 in the vertical direction (direction perpendicular to a holding surface of a chuck table described later) along the pair of guide rails 221 and 221. The grinding feed means 4 includes a male screw rod 41 disposed on the front side of the upright wall 22 and extending vertically upward and downward. The male screw rod 41 is rotatably supported by bearing members 42 and 43 whose upper end and lower end are attached to the upright wall 22. The upper bearing member 42 is provided with a pulse motor 44 as a drive source for rotationally driving the male screw rod 41, and the output shaft of the pulse motor 44 is connected to the male screw rod 41 by transmission. A connecting portion (not shown) that protrudes rearward from the center portion in the width direction is also formed on the rear surface of the movable base 31, and a through female screw hole extending in the vertical direction is formed in this connecting portion, The male screw rod 41 is screwed into the female screw hole. Therefore, when the pulse motor 44 rotates in the forward direction, the moving base 31, that is, the grinding unit 3 is lowered or moved forward, and when the pulse motor 44 rotates in the reverse direction, the moving base 31, that is, the grinding unit 3 is raised or moved backward.

  Continuing with reference to FIG. 1 and FIG. 3, a substantially rectangular working portion 211 is provided in the rear half of the main portion 21 of the housing 2, and the chuck table mechanism 5 is arranged on the working portion 211. It is installed. As shown in FIG. 3, the chuck table mechanism 5 includes a pair of guide rails 51, 51 extending in the direction indicated by arrows 51 a and 51 b that are the front-rear direction of the working unit 211 (direction perpendicular to the front surface of the upright wall 22). A movable base 52 slidably mounted on the pair of guide rails 51, 51, a cover table 54 supported by a cylindrical member 53 on the movable base 52, and a workpiece on the upper surface A chuck table 55 having a holding surface 551 for holding the chuck.

  As shown in FIG. 3, the cover table 54 has an opening 541 at the center, and the periphery of the opening 541 is attached to the upper end of the cylindrical member 53 by appropriate fixing means. The chuck table 55 is rotatably supported by the cylindrical member 53 and is disposed through an opening 541 formed at the center of the cover table 54. The chuck table 55 is rotated by a servo motor (not shown) disposed in the cylindrical member 53. The chuck table 55 is connected to suction means (not shown). Accordingly, the workpiece placed on the holding surface 551 is sucked and held by selectively communicating the chuck table 55 with a suction means (not shown).

  3, the illustrated grinding apparatus includes chuck table positioning means 56 that moves the chuck table mechanism 5 along the pair of guide rails 51 and 51 in the directions indicated by the arrows 51a and 51b. doing. The chuck table positioning means 56 includes a male screw rod 561 disposed between the pair of guide rails 51 and extending in parallel with the guide rail 51, and a servo motor 562 that rotationally drives the male screw rod 561. The male screw rod 561 is screwed into a screw hole 521 provided in the moving base 52, and a tip end portion thereof is rotatably supported by a bearing member 563 provided between the pair of guide rails 51, 51. Yes. The servo motor 562 has a drive shaft connected to the base end of the male screw rod 561 by transmission. Therefore, when the servo motor 562 rotates in the forward direction, the moving base 52, that is, the chuck table 55 moves in the direction indicated by the arrow 51a. When the servo motor 562 rotates in the reverse direction, the moving base 52, that is, the chuck table 6 moves in the direction indicated by the arrow 51b. It is done. The chuck table positioning means 56 includes a grinding area (grinding area 25 in FIG. 1) indicated by a two-dot chain line in FIG. 3 and a non-grinding area (withdrawn from the grinding area 25 as indicated by a solid line in FIG. 3). It is selectively positioned in the non-grinding region 24) in FIG.

  Returning to FIG. 1, the description will be continued. On both sides in the moving direction of the cover table 54 constituting the chuck table mechanism 5, the cross-sectional shape is a reverse channel shape, and the pair of guide rails 51, 51 and the male screw rod Bellows means 61 and 62 are attached to cover 561, servo motor 562 and the like. The bellows means 61 and 62 can be formed from any suitable material such as campus cloth. The front end of the bellows means 61 is fixed to the front wall 211 a of the working unit 211, and the rear end is fixed to the front end surface of the cover table 54 of the chuck table mechanism 5. The front end of the bellows means 62 is fixed to the rear end surface of the cover table 54 of the chuck table mechanism 5, and the rear end is fixed to the front surface 22 a of the upright wall 22 of the apparatus housing 2. When the chuck table 55 is moved in the direction indicated by the arrow 51a, the bellows means 61 is expanded and the bellows means 62 is contracted. When the chuck table 55 is moved in the direction indicated by the arrow 51b, the bellows means 61 is By being contracted, the bellows means 62 is extended.

  The grinding apparatus in the illustrated embodiment scratches the work surface, which is the upper surface of the work piece held by the holding surface 551, which is the upper surface of the chuck table 55 positioned in the non-grinding region 24, on the ground surface. A satin processing mechanism 7 to be formed is provided. The matte finishing mechanism 7 includes a pair of support members 71 and 71 disposed to face both side portions of the main portion 21 of the apparatus housing 2. A guide rod 72 disposed horizontally is fixed between the pair of support members 71, 71, and a sliding block 73 is slidably mounted on the guide rod 72. That is, the sliding block 73 is formed with a through hole through which the guide rod 72 can be inserted. By inserting the through hole into the guide rod 72, the sliding block 73 is slidably supported by the guide rod 72. The Between the pair of support members 71, 71, a male screw rod 74 disposed in parallel below the guide rod 72 is rotatably mounted. The male screw rod 74 is screwed into a female screw hole formed in the slide block 73, and one end of the male screw rod 74 is connected to an electric motor 75 mounted on one of the pair of support members 71, 71. When the electric motor 75 is driven forward and the male screw rod 74 is rotated in a predetermined direction, the slide block 73 is moved in the direction indicated by the arrow 73a. When the electric motor 75 is driven in reverse and the male screw rod 74 is rotated in the direction opposite to the predetermined direction, the sliding block 73 is moved in the direction indicated by the arrow 73b.

  A guide rail 731 is formed on the front surface of the sliding block 73 in the vertical direction, and a matte processing means 76 is movably disposed along the guide rail 731. The matte finish processing means 76 includes a case 761 having a guided groove 761a that fits into the guide rail 731. By fitting the guided groove 761a into the guide rail 731, it is supported so as to be movable along the guide rail 731. The An elevating means (not shown) such as an air cylinder is disposed between the case 761 and the sliding block 73, and the case 761 is raised and lowered along the guide rail 731 by the elevating means. An electric motor is disposed in the case 761, and its output shaft 762 is projected below the case 761. A matte processing tool 763 is attached to the output shaft 762. As shown in FIG. 4, the matte processing tool 763 includes an annular base 764 and a grinding wheel 765 mounted annularly on the lower surface of the base 764. The annular base 764 is an electric motor (not shown). Are attached to a mounter 766 mounted on the output shaft 762 by fastening bolts 767. In the illustrated embodiment, the grinding wheel 765 is configured by combining diamond abrasive grains having a particle size of 500 to 1000 μm with metal bonds, and the lower surface forms a grinding surface 765a.

  The grinding apparatus in the illustrated embodiment includes cleaning water supply means 8 for supplying cleaning water to the workpiece held on the chuck table 55 positioned in the non-grinding region 24 and / or the holding surface 551 of the chuck table 55. doing. The cleaning water supply means 8 includes a cleaning water spray nozzle 81 disposed at an intermediate portion of the main portion 21 of the apparatus housing 2, and a chuck table positioned in the non-grinding region 24 from the cleaning water spray nozzle 81. The pure water as the cleaning water is ejected toward the holding surface 551 which is the upper surface of 55.

  The description will be continued with reference to FIG. 1. On the front half of the main portion 21 of the apparatus housing 2, the first cassette 11, the second cassette 12, the workpiece temporary placing means 13, A workpiece cleaning means 14, a workpiece conveying means 15, a workpiece carrying-in means 16 and a workpiece carrying-out means 17 are arranged. The first cassette 11 stores a workpiece before grinding and is placed in a cassette carry-in area in the main portion 21 of the apparatus housing 2. The second cassette 12 is placed in a cassette unloading area in the main portion 21 of the apparatus housing 2 and stores a workpiece after grinding. The workpiece temporary placing means 13 is disposed between the first cassette 11 and the non-grinding region 24, and temporarily places the workpiece before grinding and centers it. The workpiece cleaning means 14 is disposed between the non-grinding region 24 and the second cassette 12, and cleans the workpiece after grinding. The workpiece conveying means 15 is disposed between the first cassette 11 and the second cassette 12, and the workpiece stored in the first cassette 11 is carried out to the workpiece temporary placement means 13. At the same time, the workpiece cleaned by the workpiece cleaning means 14 is conveyed to the second cassette 12. The workpiece carrying-in means 16 is disposed between the workpiece temporary placing means 13 and the non-grinding region 24, and the workpiece before grinding that is placed on the workpiece temporary placing means 13 is placed on the workpiece. It is conveyed onto the chuck table 55 of the chuck table mechanism 5 positioned in the non-grinding region 24. The workpiece unloading means 17 is disposed between the non-grinding area 24 and the workpiece cleaning means 14, and is subjected to the grinding-processed work placed on the chuck table 55 positioned in the non-grinding area 24. The object is conveyed to the workpiece cleaning means 14.

The grinding apparatus in the illustrated embodiment is configured as described above, and the operation thereof will be described mainly with reference to FIG.
5A and 5B show a perspective view of an optical device wafer processed according to the method for processing a hard substrate according to the present invention and a cross-sectional view showing an enlarged main part. An optical device wafer 10 shown in FIGS. 5A and 5B has a light emitting layer (epilayer) 110 as an optical device layer made of a nitride semiconductor on a surface 100a of a sapphire substrate 100 having a thickness of 400 μm, for example, of 5 μm. It is laminated by thickness. An optical device 130 such as a light emitting diode or a laser diode is formed in a plurality of regions partitioned by a plurality of streets 120 in which a light emitting layer (epi layer) 110 is formed in a lattice shape. In order to grind the back surface 100b of the sapphire substrate 100 constituting the optical device wafer 10 formed in this way, in order to protect the optical device 130 formed on the surface 100a of the sapphire substrate 100, FIG. And as shown to (b), the protection member T is stuck on the surface 110a of the light emitting layer (epilayer) 110. FIG. In the illustrated embodiment, the protective member T has an acrylic resin-based paste applied to the surface of a sheet base material made of polyvinyl chloride (PVC) having a thickness of 100 μm to a thickness of about 5 μm. Thus, the optical device wafer 10 in which the protective member T is adhered to the surface 110a of the light emitting layer (epi layer) 110 is accommodated in the first cassette 11 with the back surface 100b of the sapphire substrate 100 facing upward. Thus, the 1st cassette 11 which accommodated the optical device wafer 10 before a grinding process is mounted in a cassette carrying-in area as shown in FIG.

  As described above, in order to grind the optical device wafer 10 accommodated in the first cassette 11 placed in the cassette carry-in area, the workpiece conveying means 15 is operated to be accommodated in the first cassette 11. The optical device wafer 10 as the workpiece before grinding is unloaded and placed on the workpiece temporary placing means 13. The optical device wafer 10 placed on the workpiece temporary placement means 13 is positioned at the non-grinding region 24 by the workpiece carry-in means 16 after being centered here. It is placed on the holding surface 551 of the table 55. When the optical device wafer 10 is placed on the chuck table 55, the optical device wafer 10 is sucked and held on the holding surface 551 of the chuck table 55 via the protective member T by operating a suction means (not shown). The When the optical device wafer 10 is sucked and held on the chuck table 55 in this way, the holding surface 551 that is the upper surface of the chuck table 55 positioned in the non-grinding region 24 is held by operating the matte finishing mechanism 7. A satin processing step is performed in which the back surface 100b of the sapphire substrate 100 is scratched and formed on the satin surface.

  As shown in FIG. 7, the matte finishing process rotates the chuck table 55 in the direction indicated by the arrow 55a at a rotational speed of, for example, 100 rpm, and the matte finish processing tool 763 of the matte finishing means 76 in the direction indicated by the arrow 763a, for example, 1000 rpm. It rotates at the rotation speed. Then, the satin processing tool 763 is lowered and moved at a feed rate of, for example, 1 to 1.5 μm / second, and the back surface of the sapphire substrate 100 constituting the optical device wafer 10 in the direction indicated by the arrows 73a and 73b. For example, a machining feed that reciprocates once in 10 seconds along 100b (upper surface) is performed. As a result, the grinding surface 765a of the grinding wheel 765 constituting the matting tool 763 acts on the back surface 100b of the sapphire substrate 100, and the back surface 100b of the sapphire substrate 100 is satin-finished. As described above, the grinding wheel 765 to be textured in this textured process is formed by bonding diamond abrasive particles having a large particle size of 500 to 1000 μm with metal bonds, so that the back surface 100b of the sapphire substrate 100 is formed. Even if it is formed on the mirror surface, the so-called bite is good, and it can be easily formed on the satin surface as shown in FIG. 8 without slipping. The processing amount in the satin processing step is set to 10 μm in the illustrated embodiment. Therefore, the thickness of the sapphire substrate 100 constituting the optical device wafer 10 on which the satin processing step is performed is 390 μm.

  When the above-described satin finishing process is performed, the satin finishing means 76 is positioned at the standby position, the chuck table positioning means 56 is operated, and the chuck table 55 is moved in the direction indicated by the arrow 51a. It is positioned in the grinding area shown (grinding area 25 in FIG. 1). If the chuck table 55 is positioned in the grinding area 25, the back surface 100b of the sapphire substrate 100 constituting the optical device wafer 10 on which the matte finish process has been performed is ground with a grinding wheel composed mainly of diamond abrasive grains. A grinding step of grinding to a predetermined thickness is performed.

  In the grinding process, as shown in FIG. 9, the chuck table 55 is rotated in the direction indicated by the arrow 55a at a rotational speed of, for example, 750 rpm, and the grinding wheel 325 is rotated in the direction indicated by the arrow 325a, for example, at a rotational speed of 1000 rpm. Then, the pulse motor 44 of the grinding feed means 4 is driven forward so that the grinding wheel 325 is ground and fed in the direction indicated by the arrow 325b at a grinding feed rate of 1 to 1.5 μm / second, for example, and the grinding surface 327a of the grinding wheel 327 is obtained. Is fed by grinding, for example, 290 μm from the position in contact with the back surface 100b (upper surface) of the sapphire substrate 100, which is the surface to be processed. As a result, the back surface 100b of the sapphire substrate 100 is ground, and the sapphire substrate 100 is formed to a thickness of 100 μm in the illustrated embodiment. In this grinding process, the grinding water supply means 320 is operated to feed the grinding water to the grinding wheel 327 that constitutes the grinding wheel 325 through the grinding water supply passage 322a and the grinding water supply hole (not shown) provided in the mounter 324. To be supplied. In the grinding process carried out in this way, the back surface 100b of the sapphire substrate 100, which is the work surface, is formed on the matte surface as described above, so that the so-called biting by the grinding stone 327 is good, and as described above. Even if the grinding wheel 327 is formed by bonding fine diamond abrasive grains having a particle diameter of 10 to 50 μm with vitrified bonds, grinding starts and grinding progresses. Therefore, the problem that the sapphire substrate 100 is damaged can be solved by increasing the pressing force of the grinding wheel 327 by sliding grinding feed on the back surface 100b (upper surface) of the sapphire substrate 100, which is a hard substrate.

  When the above-described grinding process is performed, the pulse motor 44 of the grinding feed means 4 is driven in reverse to raise the spindle unit 32 to the standby position to stop the rotation of the grinding wheel 325 and stop the rotation of the chuck table 55. .

  Next, the chuck table positioning means 56 is actuated to bring the chuck table 55 holding the optical device wafer 10 on which the back surface 100b of the sapphire substrate 100 is ground as described above to the non-grinding region (not shown in FIG. 1). Position in the grinding area 24). If the chuck table 55 is positioned in the non-grinding region 24, the sapphire substrate constituting the ground optical device wafer 10 held by the chuck table 55 from the cleaning water jet nozzle 81 by operating the cleaning water supply means 8 is operated. The cleaning surface (pure water) is sprayed on the back surface 100b (processing surface) of 100 to clean the processing surface that is the back surface 100b of the sapphire substrate 100. By this cleaning, the grinding water containing the grinding waste adhering to the processing surface which is the back surface 100b of the sapphire substrate 100 is simply removed (simple cleaning process). When the simple cleaning process is thus performed, the suction holding of the optical device wafer 10 by the chuck table 55 is released. Then, the wafer unloading means 17 is operated to unload the optical device wafer 10 from the chuck table 55 and convey it to the cleaning means 14. The optical device wafer 10 transported to the cleaning means 14 is cleaned here (cleaning step), and then stored in a predetermined position of the second cassette 12 by the workpiece transport means 15.

2: Grinding device housing 3: Grinding unit 32: Spindle unit 322: Rotating spindle 325: Grinding wheel 327: Grinding wheel 4: Grinding feed means 5: Chuck table mechanism 55: Chuck table 56: Chuck table positioning means 7: Pear finish Machining mechanism 76: satin finish processing means 763: satin finish processing tool 766: grinding wheel 10: optical device wafer 100: sapphire substrate 11: first cassette 12: second cassette 13: workpiece temporary placement means 14: cleaning means 15: Wafer carrying means 16: Wafer carrying means 17: Wafer carrying means

Claims (2)

A method of grinding a hard substrate to form a predetermined thickness by grinding a work surface of the hard substrate,
A matte processing step in which a grinding wheel is brought into contact with the processing surface of the hard substrate and rotated at different rotation speeds to scratch the processing surface of the hard substrate and form on the matte surface;
The processed surface of the rigid substrate該梨land processing step is performed by grinding the configured grinding wheel as the main component of diamond abrasive grains, seen including and a grinding step for grinding to a predetermined thickness,
The satin finish processing step is performed by a grinding wheel composed mainly of diamond abrasive grains having a particle size of 500 to 1000 μm, and the grinding step is grinding composed mainly of diamond abrasive grains having a particle size of 10 to 50 μm. Carried out with a grinding wheel,
A method for grinding a hard substrate. A chuck table having a holding surface for holding a workpiece, a grinding wheel having a grinding wheel for grinding the workpiece held on the holding surface of the chuck table, and for rotating the grinding wheel Grinding means provided with a drive source, grinding feed means for grinding and feeding the grinding means in a direction perpendicular to the holding surface of the chuck table, grinding area by the grinding means, and retreating from the grinding area A chuck table positioning means positioned in the non-grinding region, and a grinding apparatus comprising:
In the non-grinding area, a matte finishing means provided with a satin processing tool for scratching the workpiece surface of the workpiece held on the chuck table and forming it on the matte ground is disposed,
The satin processing tool is provided with a grinding wheel composed mainly of diamond abrasive grains having a particle size of 500 to 1000 μm so as to come into contact with the processing surface of the workpiece and be rotated at a rotation speed different from that of the chuck table. Configured,
The grinding wheel includes a grinding wheel composed mainly of diamond abrasive grains having a particle size of 10 to 50 μm.
A grinding apparatus characterized by that.

Images