JP2010131806A - METHOD FOR DIVIDING AlTiC SUBSTRATE - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for dividing an AlTiC substrate which can improve productivity by cutting down a cut plane polishing process. <P>SOLUTION: The method for dividing the AlTiC substrate having lines along which the substrate is to be divided includes a machined groove forming process for forming a laser-machined groove by radiating laser beams along the lines and a cleavage process for cleaving the substrate along the laser-machined groove. The laser beams is made incident from the back of the AlTiC substrate, and the laser-machined groove is formed to be open in the back of the AlTiC substrate. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an artic substrate dividing method for dividing an artic substrate into blocks, bars, or chips.

  Altic (alumina / titanium / carbite composite ceramics / ALTiC), which is a fired material of alumina and titanium carbide, is used as a head slider for a recording medium (hard disk). In general, a head slider for a storage medium is created by cutting an aluminum substrate formed in a wafer shape into a predetermined size using a cutting means such as a cutting blade and dividing it.

  However, since Altic has a very hard Vickers hardness of about 2000, even if a cutting blade containing superabrasive grains such as diamond abrasive grains or CBN abrasive grains is used, cutting takes a very long time.

  In addition, in order to use a chip obtained by dividing an Altic substrate as a head slider for a storage medium, it is necessary to finish the surface roughness of the cut surface with high accuracy, for example, surface accuracy of 20 nm or less. Dividing into chips has a very complicated process.

  Specifically, after the artic substrate is once divided into a plurality of blocks, each block is cut into a strip of an appropriate size, and after the side of this strip is polished, it is further cut into a bar shape of 1 chip width, Divide into chips. The remaining strip from which the 1-chip width bar is cut out is polished on the cut surface, and the 1-chip width bar is cut out sequentially.

As an apparatus for performing such processing, Japanese Patent Application Laid-Open No. 2001-277110 discloses a processing apparatus that performs cutting by a cutting unit and polishing by a polishing unit with a single unit.
JP 2001-277110 A

  However, even with the processing device as disclosed in Patent Document 1, it takes a long time to cut with a cutting blade, and further, after cutting once, sufficient polishing is necessary, so the work is very difficult. In addition, it is complicated and requires a lot of work, and as a result, the production cost of the storage medium head slider increases.

  On the other hand, Altic, which is a calcined material, has a characteristic of having excellent cleaving properties, similar to a crystal.

  The present invention has been made in view of such points, and the object of the present invention is to provide a method for dividing an Altic substrate that can reduce the polishing process of the cut surface and improve the productivity. is there.

  According to the present invention, there is provided a method for dividing an Altic substrate having a planned dividing line, wherein the laser processed groove is formed by irradiating the Altic substrate with an absorptive laser beam along the planned divided line. There is provided a method for dividing an Altic substrate comprising a forming step and a cleavage step of cleaving the Altic substrate along the laser processing groove.

  Preferably, the division line includes a bar-shaped division line that divides the Altic substrate into a plurality of bars and a chip division line that divides each bar into a plurality of chips. Preferably, the laser beam is incident from the back surface side of the Altic substrate, and the laser processing groove is formed to open on the back surface of the Altic substrate.

  Preferably, the method for dividing the Altic substrate further includes a laser processing groove removing step of removing a thickness corresponding to the depth of the laser processing groove from the laser beam irradiation surface of the Altic substrate after performing the cleavage step. The laser processing groove removing step is performed by any one of grinding, polishing, and etching. Preferably, the depth of the laser processing groove is 5 to 10% with respect to the thickness of the AlTiC substrate.

  According to the method for dividing an Altic substrate according to the present invention, after the laser beam having the absorptivity to the Altic substrate is irradiated along the planned dividing line to form the laser processed groove along the planned dividing line, Then, the Altic substrate is cleaved along and divided into individual chips.

  By using a laser beam, processing time can be shortened compared to processing using a cutting blade. Further, the cleavage surface of Altic has high surface accuracy, so that a polishing step is not required and productivity can be improved.

  According to the third aspect of the present invention, it is possible to prevent damage caused by laser irradiation of the pattern or device formed on the Altic substrate by making the laser beam incident from the back side of the Altic substrate.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic configuration diagram of a laser processing apparatus 2 suitable for carrying out the method for dividing an Altic substrate according to the present invention. First, the configuration of the laser processing apparatus 2 will be described before describing the method for dividing the Altic substrate of the present invention.

  The laser processing apparatus 2 includes a first slide block 6 mounted on a stationary base 4 so as to be movable in the X-axis direction. The first slide block 6 is moved in the X-axis direction along the pair of guide rails 14 by the X-axis feed means 12 constituted by the ball screw 8 and the pulse motor 10.

  A support box 16 is mounted on the first slide block 6 so as to be movable in the Y-axis direction. The support box 16 is moved in the Y-axis direction along a pair of guide rails 24 by a Y-axis feed means (index feed means) 22 composed of a ball screw 18 and a pulse motor 20.

  A chuck table 28 is rotatably mounted on the support box 16. As best shown in FIG. 2, the support box 16 is generally U-shaped, and connects the upper plate 16a, the lower plate 16b mounted on the guide rail 24, and the upper plate 16a and the lower plate 16b. The connecting plate 16c is included. The upper plate 16a is formed with a circular opening 17 into which a fitting projection (to be described later) of the chuck table 28 is rotatably mounted.

  The chuck table 28 includes an annular support member 62 and a holding pad 74. The annular support member 62 includes a fitting convex portion 64, a belt winding portion 66 having a larger diameter than the fitting convex portion 64, and an annular accommodating portion 68 having substantially the same diameter as the fitting convex portion 64.

  The annular housing portion 68 has an inner diameter 68a (see FIG. 4) that is substantially the same as the outer shape of the holding pad 74, and an annular support portion 70 that supports the holding pad 74 is formed on the inner bottom portion of the annular housing portion 68. Yes.

  The holding pad 74 is made of a transparent material such as quartz glass, borosilicate glass, sapphire, calcium fluoride, lithium fluoride, and magnesium fluoride, and has a large number of pores 76 that open to the surface (holding surface) 74a. have.

  As apparent from FIG. 4, each of the pores 76 communicates with the suction groove 78, and a communication path 72 that communicates with the suction groove 78 of the holding pad 74 is formed in the annular support portion 70 of the annular support member 62. Has been. The communication path 72 is connected to the vacuum suction source 80.

  When the holding pad 74 is mounted on the annular support portion 70 of the annular support member 62 and the fitting convex portion 64 of the annular support member 62 is fitted into the circular opening 17 of the support box 16, as shown in FIG. 28 is rotatably mounted on the support box 16.

  A motor 26 is attached to the connection plate 16 c of the support box 16, and the belt 30 is wound around the pulley 27 connected to the output shaft of the motor 26 and the belt winding portion 66 of the annular support member 62. . When the motor 26 is driven, the chuck table 28 is rotated via the belt 30.

  The motor 26 is composed of, for example, a pulse motor. When the motor 26 is driven with a predetermined pulse during alignment, the chuck table 28 is rotated by a predetermined amount (θ rotation), and the line to be divided (street) of the Altic substrate 1 shown in FIG. ) 3a, 3b, 3c can be aligned.

  A plurality of (four in this embodiment) frame support bases 29 are formed on the upper plate 16a of the support box 16, and these frame support bases 29 support an annular frame described later.

  Referring to FIG. 1 again, the machining feed means 23 is constituted by the X-axis feed means 12 and the Y-axis feed means 22. Therefore, the chuck table 28 can be moved in the X-axis direction and the Y-axis direction by the processing feed means 23.

  A column 32 is erected on the stationary base 4, and a casing 35 containing a laser beam oscillation means 34 is attached to the column 32. The laser beam oscillated from the laser beam oscillating means 34 is condensed by an objective lens of a condenser (laser irradiation head) 36 attached to the tip of the casing 35, and is applied to an artic substrate held on the chuck table 28. Irradiated.

  At the tip of the casing 35, a second imaging unit 38 is disposed that is aligned with the condenser 36 in the X-axis direction and detects a processing region to be laser processed by a laser beam. The second imaging means 38 includes an infrared imaging means for irradiating the workpiece with infrared rays, an optical system for capturing the infrared rays emitted by the infrared irradiation means, in addition to an ordinary imaging device such as a CCD for imaging with visible light, and this optical system. Infrared imaging means including an imaging device such as an infrared CCD that outputs an electrical signal corresponding to infrared rays captured by the system is included, and the captured image is transmitted to the controller 40.

  The controller 40 is configured by a computer, and a central processing unit (CPU) 42 that performs arithmetic processing by a control program, a read-only memory (ROM) 44 that stores a control program and the like, and a readable and writable memory that stores arithmetic results and the like. A random access memory (RAM) 46, a counter 48, an input interface 50, and an output interface 52 are provided.

  Reference numeral 56 denotes a processing feed amount detection means comprising a linear scale 54 disposed along the guide rail 14 and a read head (not shown) disposed on the first slide block 6. The detection signal is input to the input interface 50 of the controller 40.

  Reference numeral 60 denotes index feed amount detection means comprising a linear scale 58 disposed along the guide rail 24 and a read head (not shown) disposed on the second slide block 16. The detection signal is input to the input interface 50 of the controller 40.

  The image signal picked up by the second image pickup means 38 is input to the input interface 50 of the controller 40. On the other hand, a control signal is output from the output interface 52 of the controller 50 to the pulse motor 10, the pulse motor 20, the laser beam oscillation means 34, and the like.

  An image pickup means (first image pickup means) 82 for picking up an image of the AlTiC substrate held by the chuck table 28 from below the transparent holding pad 74 is attached to a predetermined portion of the base 4 of the laser processing apparatus 2.

  As shown in FIG. 5, the imaging means 82 includes a camera unit 84 having a low magnification camera 86 and a high magnification camera 88. Two illumination devices 90 and 92 for illuminating the imaged part at the time of imaging by the camera unit 84 are attached to the side surface of the camera unit 84.

  The camera unit 84 is supported by a support plate 94, and the base end portion of the support plate 94 is fixed to the Z-axis moving block 98. A column 96 is erected on the base 4 of the laser processing apparatus 2, and the camera unit 84 constituting the imaging means 82 is constituted by a pair of guide rails by the Z-axis moving means 104 constituted by the ball screw 100 and the pulse motor 102. It is moved along the Z-axis direction (vertical direction) along 106.

  Referring to FIG. 6 (A), a perspective view of the surface side of the Altic substrate 1 to be processed by the laser processing apparatus 2 is shown. On the surface 1a of the Altic substrate 1, a block division scheduled line 3a that divides the Altic substrate 1 into blocks, a bar-shaped division planned line 3b that divides the divided block into bars, and a chip division that divides each bar into chips A line 3c is formed. When each bar is divided by the chip division planned line 3c, the chip 5 is obtained.

  FIG. 6B shows a front perspective view of the AlTiC substrate 1A in which the pattern of the block division planned line 3a is different from that in FIG. 6A. The AlTiC substrate 1A also has a block division planned line 3a, a bar-shaped division planned line 3b, and a chip divided planned line 3c.

  In the processing by the laser processing apparatus 2 shown in FIG. 1, the Altic substrates 1 and 1A are attached to the dicing tape (adhesive tape) T with the surface 1a side down, and the outer periphery of the dicing tape T is shown in FIG. As shown in FIG. Therefore, the AlTiC substrate 1 is mounted on the chuck table 28 in the state shown in FIG.

  Referring to FIG. 8, a partial cross-sectional side view of the support box and chuck table portion is shown. Since the support box 16 is substantially U-shaped, an imaging means entry opening 19 is defined on the opposite side of the connecting plate 16c that connects the upper plate 16a and the lower plate 16b. In this figure, the processing feed means 23 is schematically shown.

  FIG. 9 is an enlarged partial cross-sectional view of a portion A in FIG. 8. The Altic substrate 1 is attached to the dicing tape T with the surface 1a facing down, and the annular frame F is placed on the frame placing table 29. ing.

  As described above, the holding pad 74 of the chuck table 28 is made of a transparent material such as glass and has a plurality of suction grooves 78. The suction groove 78 is connected to the vacuum suction source 80 via a communication path 72 formed in the annular support member 62 (see FIG. 4).

  As shown in FIG. 10, the holding pad 74 includes a suction path forming area 74a in which a plurality of suction paths such as pores or suction grooves are formed, and a cross-shaped suction path non-forming area 74b in which no suction path is formed. And an outer peripheral region 74c in which no suction path is formed. Imaging of the Altic substrate 1 by the first imaging means 82 is preferably performed through the suction path non-formation region 74b in order to capture the target pattern clearly.

  Hereinafter, an alignment operation using the first imaging unit 82 will be described. As shown in FIG. 8, the annular frame F is mounted on the frame mounting table 29, the vacuum suction source 80 is operated, and the Altic substrate 1 is sucked and held by the holding pad 74 of the chuck table 28.

  In this state, the X-axis feeding means 12 and the Y-axis feeding means 22 are driven to cause the first imaging means 82 to enter the support box 16 through the imaging means entry opening 19 as shown in FIG. The means 82 is positioned directly below the Altic substrate 1.

  When the first imaging means 82 is positioned directly below the Altic substrate 1, the illumination device 90 or 92 is turned on to illuminate the Altic substrate 1 from below, and the Altic substrate is passed through the transparent pad 74 with the low-magnification camera 86 or the high-magnification camera 88. The surface of 1 is imaged, and the captured image is displayed on a display such as an LCD (not shown).

  Based on the captured image, the block division planned line 3a, the bar shape division planned line 3b, and the chip division planned line 3c are detected, and these values are stored in the RAM 46 of the controller 40.

  When performing laser processing along the block division scheduled line 3a of the Altic substrate 1, pattern matching between the stored image and the image actually captured and acquired by the first imaging unit 82 is performed to perform laser processing. The block division planned line 3a and the condenser (laser irradiation head) 36 are aligned, and the alignment at the time of block division is completed.

  Regarding the bar shape division planned line 3b and the chip division planned line 3c, the alignment of the bar shape division planned line 3b and the laser irradiation head 36 to be laser processed or the alignment of the chip division planned line 3c and the laser irradiation head 36 is performed. The alignment at the time of bar division and chip division is completed.

  When the alignment is completed, as shown in FIG. 11, the laser irradiation head 36 irradiates the Altic substrate 1 from the back surface 1 b side to form a condensing point 37 inside the Altic substrate 1. The condensing point 37 is set to a depth of 5 to 10% of the thickness from the back surface 1 b of the Altic substrate 1.

  The processing conditions of the laser processing groove forming step of the present embodiment are as follows, for example.

Light source: YAG
Wavelength: 355nm
Average output: 6.2W
Repeat frequency: 15 kHz
Feeding speed: 50mm / s
Condensing spot diameter: φ20μm
Here, the laser beam having a wavelength of 355 nm is the third harmonic (THG) of the YAG laser, and has an absorptivity with respect to the Altic substrate 1. When the chuck table 28 is moved at a feed rate of 50 mm / s in the X1 direction in FIG. 11 while irradiating the laser beam of the above-described condition with the laser irradiation head 36, the back surface 1b of the Altic substrate 1 is applied as shown in FIG. A laser processing groove 39 is formed.

  The laser processing groove 39 corresponds to a processing groove for dividing a block into bars, but a block processing groove or a chip processing groove can be formed in the same manner. The depth of the laser processed groove 39 is preferably 5 to 10% of the thickness of the Altic substrate 1.

  As described above, in the present embodiment, since the laser processing groove 39 is formed by making the laser beam incident from the back side of the Altic substrate 1, damage to the pattern or device formed on the Altic substrate 1 due to laser irradiation can be prevented. it can.

  When the laser-processed groove forming step is completed, since the Altic substrate 1 as the fired material has excellent cleaving property as the crystal body, the cleavage step shown in FIG. 13 is performed. That is, the back surface 1 b side of the Altic substrate 1 supported by the annular frame F via the dicing tape T is placed on the support table 110 having the opening 112.

  Specifically, the Altic substrate 1 is placed on the support table 110 so that the laser processing groove 39 of the Altic substrate 1 is positioned in the opening 112, and the breaker 114 is rapidly moved in the direction of arrow A to dicing tape T. When the shock is applied to the AlTiC substrate 1 via, the AlTiC substrate 1 is cleaved cleanly starting from the laser processing groove 39.

  When the cleaving process is performed on all the laser processed grooves 39, a plurality of bars 43 (see FIG. 15) are obtained. In FIG. 15, reference numeral 41 denotes a cleavage portion. When the cleavage step is completed, the thickness of the Altic substrate 1 having a depth corresponding to the laser processing groove 39 is removed by grinding using a grinding device 116 whose main part is shown in FIG.

  In FIG. 14, 118 is a chuck table, and 120 is a grinding unit. The grinding unit 120 is configured by bolting a grinding wheel 126 in which a plurality of grinding wheels 128 are arranged in an annular shape to a mounter 124 formed at the tip of a spindle 122 that is rotationally driven by a motor (not shown).

  The artic substrate 1 supported by the annular frame F is sucked and held by the chuck table 118, and the grinding wheel 126 is rotated in the arrow B direction at, for example, 6000 rpm while the chuck table 118 is rotated in the arrow A direction at, for example, 6000 rpm. 1 is ground to remove the thickness corresponding to the laser processing groove 39.

  Thereby, the damaged part by laser processing can be removed, and deterioration of chip quality, such as reduction in bending strength, can be prevented. Since the thickness region corresponding to the laser processing groove depth is damaged by laser processing, it can be removed by grinding in a short time. The removal of the thickness corresponding to the laser processing groove depth may be performed by either polishing or etching instead of the grinding shown in FIG.

  FIG. 15 shows a state where the thickness corresponding to the laser processing groove depth is removed. The Altic substrate 1 is divided into a plurality of bars 43 at the cleavage part 41. Since the Altic substrate 1 is adhered to the dicing tape T, the original shape of the Altic substrate 1 is maintained as a whole even after being divided into a plurality of bars 43 by the cleavage portions 41. Since the cleavage surface of the Altic substrate 1 is a very beautiful mirror surface, it is possible to reduce the time required for the polishing process, which has been conventionally required, or to completely omit the polishing process.

  The present invention includes the following two processes. The first process consists of (1a) alignment of the bar-shaped division planned line 3b, (1b) formation of the laser processing groove 39 along the bar-shaped division planned line 3b, (1c) cleavage into a plurality of bars, (1d) cleavage. The bar is attached to a dicing tape T supported by one or a plurality of annular frames F, (1e) alignment of the chip division planned line 3c, (1f) the laser processing groove 39 along the chip division planned line 3c (1g) Each step of changing to each chip by cleavage is included.

  The second process includes the following steps. This second process is applied to an AlTiC substrate 1A having a pattern as shown in FIG.

  (2a) Alignment of the block division planned line 3a, (2b) Formation of a laser processing groove 39 along the block division planned line 3a, (2c) Cleaving into the block, (2d) Supporting one or more blocks on the annular frame F (2e) Alignment of the bar-shaped division planned line 3b, (2f) Formation of a laser processing groove 39 along the bar-shaped division planned line 3b, (2g) Cleaving the block into a plurality of bars (2h) Stick one or more bars to the dicing tape T supported by the annular frame F, (2i) Alignment of the chip division planned line 3c, (2j) Laser processing groove 39 along the chip division planned line 3c (2k) Individual change to each chip by cleavage.

It is a schematic perspective view of the laser processing apparatus suitable for implementing the division | segmentation method of the Altic board | substrate of this invention. It is a disassembled perspective view of a support box and a chuck table part. It is a perspective view of the chuck table mounted on the support box. It is a disassembled sectional view of a chuck table. It is a perspective view of a 1st imaging means and its support structure. It is a surface side perspective view of an Altic substrate. It is a back surface side perspective view of the Altic board mounted in the annular frame via the dicing tape. It is a partial cross section side view of the chuck table mounted on the support box. It is a partial cross-sectional enlarged view of A part of FIG. It is a top view of a holding pad. It is explanatory drawing of a laser processing groove | channel formation process. It is a longitudinal cross-sectional view of the Altic board | substrate with which the laser processing groove | channel was formed. It is sectional drawing for demonstrating a cleavage process. It is a perspective view of a laser processing groove removal process. It is a longitudinal cross-sectional view of the Altic board | substrate from which the thickness equivalent to the laser processing groove depth was ground and removed.

Explanation of symbols

1,1A Altic substrate 2 Laser processing device 3a Block division planned line 3b Bar shape division planned line 3c Chip division planned line 5 Chip 28 Chuck table 36 Condenser (laser irradiation head)
39 Laser processing groove 41 Cleaving portion 43 Bar 74 Holding pad 82 First imaging means 110 Support table 114 Breaker

Claims (6)

A method for dividing an Altic substrate having lines to be divided,
A laser processing groove forming step of forming a laser processing groove by irradiating the laser beam having an absorptivity with respect to the Altic substrate along the division line;
A cleavage step of cleaving the Altic substrate along the laser processed groove;
A method for dividing an Altic substrate, comprising: The division line is a bar-shaped division line that divides the Altic substrate into a plurality of bars;
2. A method for dividing an Altic substrate according to claim 1, further comprising a chip division scheduled line for dividing each bar into a plurality of chips. The laser beam is incident from the back side of the Altic substrate,
The method for dividing an artic substrate according to claim 1 or 2, wherein the laser processed groove is formed to be opened on a back surface of the artic substrate.   The method for dividing an Altic substrate according to any one of claims 1 to 3, further comprising a processed groove removing step of removing a thickness corresponding to the depth of the laser processed groove from the Altic substrate after performing the cleavage step.   5. The method for dividing an Altic substrate according to claim 4, wherein the laser processing groove removing step comprises any one of a grinding step, a polishing step, and an etching step.   6. The method for dividing an Altic substrate according to claim 1, wherein the laser processing groove has a depth of 5 to 10% with respect to the thickness of the Altic substrate.

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