JP2010214550A - Chamfering device of silicon ingot, and chamfering method of prismatic silicon ingot using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chamfering device of a prismatic silicon ingot having short throughput time and compact footprints. <P>SOLUTION: The prismatic silicon ingot (w) left with four circular-arc corner parts by slicing four surrounding sides is fixed (s<SB>1</SB>) in a vertical direction by a clamping mechanism (3), and is chamfered as follows: (A) The four circular-arc corner parts are chamfered by rough-grinding by using a cup wheel type grinding tool (4f)(s<SB>2</SB>), (B) Four side surface planes are chamfered by grinding by using a cup wheel type grinding tool (5f)(s<SB>3</SB>), (C) The four rough-ground circular-arc corner parts are chamfered by finish-grinding (s<SB>4</SB>) by using an outer peripheral surface of a cylindrical grinding tool (6f), and (D) The four side surface planes ground by using a polishing brush (7f) are chamfered by finish-polishing (s<SB>5</SB>). A chamfering throughput time for each one prismatic silicon ingot is the sum of round part chamfering rough-grinding time at a corner part circular-arc rough-grinding stage (s<SB>2</SB>) in a rate-limited process and several seconds required for 72°-rotation of an index type rotary table (2). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a chamfering apparatus for a prismatic polycrystalline silicon ingot or single crystal silicon ingot, which is a raw material of a square or rectangular substrate used as a substrate for a solar cell, and a chamfering method for a silicon ingot using the same. When a silicon ingot is sliced into a thickness of 200 to 240 μm by a wire cutting method to obtain many silicon substrates for solar cells at the same time, the surface of the silicon ingot is used to give a prismatic or cylindrical silicon ingot without chipping or cracking at the time of cutting. Is used to chamfer 10 to 10,000 μm uniformly using a grinding tool and a polishing tool.

  In the process of manufacturing a silicon substrate for solar cells, a cylindrical single crystal silicon ingot is cut into four round sections with a band saw to form a prismatic silicon ingot (workpiece) with an arc left at the corner, followed by a horizontal shape. A cylindrical grinding device is supported by a clamp device composed of a headstock and a tailstock, and the four side surfaces are chamfered to a desired thickness (8 to 10 mm) with a cup wheel type grindstone, and then sliced into a square shape having a thickness of 200 to 330 μm. A silicon substrate is manufactured (for example, see Non-Patent Document 1).

Also, as a prismatic silicon ingot, the molten metal silicon (S _i ) melt is poured into a prismatic graphite container and solidified in one direction, and then the bottom surface and side surfaces contaminated by contact with the container inner surface are chamfered. When the production of a polycrystalline silicon ingot or a semiconductor substrate is quiet, the four sides of a cylindrical silicon ingot for manufacturing a semiconductor substrate are cut with a slicer, leaving part of the R, and then both end faces are chamfered, Then, after corner R chamfering of the columnar ingot (the machining allowance is 7.5 to 8 mm), the four side surfaces are chamfered (the machining allowance is 0.5 to 1 mm), and the prismatic single unit for solar cells is used. A crystalline silicon ingot is used. A single crystal silicon substrate has a higher light conversion rate than a polycrystalline silicon substrate, but it is said that chamfering is difficult.

  For example, a metal silicon melt obtained by reducing quartzite or silica sand in an electric furnace is poured into a heat-resistant columnar container, and gradually cooled from the lower end to the upper end of the container, so that it is solidified in one direction. Proposed a method to produce a polycrystalline silicon ingot by using a crystalline silicon ingot rod, grinding the lower end and side surfaces contaminated with the inner surface of the container by 5mm, grinding and polishing, and etching with hydrofluoric acid / nitric acid mixed aqueous solution. (For example, refer to Patent Document 1).

  A wire-cut saw has been proposed as a slicer that uses an etched prismatic polycrystalline silicon ingot as a silicon substrate for a solar cell having a thickness of 200 to 330 μm (see, for example, Patent Document 2).

  Further, the side surfaces adjacent to each other of the prismatic polycrystalline silicon ingot moving at 0.3 m / min in the horizontal direction are subjected to rough chamfering with a pair of coarse polishing brushes rotating at 630 to 650 rpm, and then 0 to 0 in the horizontal direction. There has also been proposed a method of finishing chamfering of adjacent side surfaces of a rough chamfered prismatic polycrystalline silicon ingot moving at 1 m / min with a pair of rotating finishing polishing brushes (see, for example, Patent Document 3). In addition, an industrial brush in which abrasive-containing monofilament brush hairs are planted on a rotating substrate is also known (see Non-Patent Document 2).

  On the other hand, horizontal cylindrical grinding apparatuses that chamfer the surface of a cylindrical silicon ingot for manufacturing a silicon substrate for a semiconductor substrate are also known (see, for example, Patent Document 4, Patent Document 5, Patent Document 6, and Patent Document 7). ).

  These horizontal cylindrical grinding apparatuses disclosed in Patent Documents 4 to 6 are a clamp mechanism comprising a pair of a headstock that rotates a center shaft by a servo motor via a speed reduction mechanism and a tailstock that is movable in the left-right direction. And a spindle on the circumferential upper surface of the cylindrical ingot supported by the spindle center sinter and the tailstock center of the clamp mechanism in a horizontal (lateral) direction and rotatably. An elevating mechanism that raises and lowers a grinding head supported by a grindstone shaft so that a circular flat surface of the flat grindstone faces, and a linear movement mechanism that moves the grinding head to the left and right parallel to the axis of the cylindrical ingot.

Cylindrical grinding of a cylindrical silicon ingot is performed by lowering the bottom surface of the disk-shaped flat grindstone to a chamfering height position at the height of the circumferential upper surface of the rotating cylindrical ingot, and then grinding by a linear movement mechanism. Move the head to the right and rotate the disc-shaped flat grindstone of the grinding head to the upper surface of the circumference of the cylindrical ingot while making contact with the cylindrical ingot to start cutting. After reaching the right end position, the disc-shaped flat grindstone is lowered by the elevation mechanism by the lifting mechanism, the moving direction of the disc-shaped flat grindstone is reversed to the left by the linear moving mechanism, and then the disc-shaped flat grindstone After the grindstone reaches the left end position of the cylindrical ingot, the disc-shaped flat grindstone is lowered by the lifting mechanism and the grinding head is moved to the right by the linear moving mechanism, and the disc-shaped flat After the stone reaches the right end position of the cylindrical ingot, the disk-shaped flat grindstone is lowered by the height of the cut amount by the lifting mechanism, the moving direction of the disk-shaped flat grindstone is reversed to the left by the linear moving mechanism, Then, after the disc-shaped flat grindstone reaches the left end position of the cylindrical ingot, the disc-shaped flat grindstone is repeatedly lowered, reversed, chamfered, lowered, reversed, and chamfered to obtain a desired thickness (10 μm to 5 mm). Chamfering is performed.

  The present inventors use this horizontal cylindrical grinding apparatus to support a prismatic silicon ingot having a side of 156 mm and a length of 250 mm between the tailstock center and the tailstock center, and chamfering the surface of the prismatic silicon ingot. I tried machining, but the contact area of the disk-shaped flat grindstone is large, and even when chamfering the outer circumferential surface of the circumference, the surface roughness is 2 to 5 μm, and chamfering with a surface roughness of 1 μm or less is difficult There was found.

  As the length of one side of a prismatic silicon ingot is increased from 50 mm to 125 mm, 156 mm, 200 mm, and 240 mm, a prismatic silicon ingot having a side of 156 mm to 240 mm is sliced at once with a wire-cut saw and has a thickness of 200 to 330 μm. When mass-producing silicon substrates for solar cells, chipping often occurs at the corners of prismatic silicon ingots, and it has been pointed out by substrate processing manufacturers that the production loss rate of silicon substrates is increasing. This chipping phenomenon often occurs even when cutting a wire of a cylindrical silicon ingot for a semiconductor substrate.

  It is currently about 95-120 minutes for chamfering a prismatic single crystal silicon ingot that is 156mm on one side and 250mm in height and cut off at the four corners, leaving four corners, 156mm on one side, and 500mm in height. The actual situation is that it takes about 180 to 210 minutes to chamfer the prismatic single crystal silicon ingot that has been cut leaving the R portion.

  Solar cells are attracting attention as part of Earth Green Ecology and President Obama's Green Newdale policy, and silicon substrate processing manufacturers for solar cells can chamfer the surface of a prismatic silicon ingot with sides of 156 to 330 mm, and They want the appearance of a chamfering device with a small machine installation area.

JCM Co., Ltd., “Solar Cell Manufacturing Equipment Single Crystal Fully Automatic Line”, [Online], March 9, 2009 Search, Internet <URL: http://www.e-jcm.co.jp/SolarCell/ Mono / Auto / ＞ JP-A-8-73297 US Published Patent No. 2008 / 0223351A1 Specification Japanese Patent No. 3405411 Showa Industry Co., Ltd., “Industrial Brush Consultant Showa Industry”, [Online], Search on March 16, 2009, Internet <URL: http://www.skbrush.co.jp/> JP-A-4-322965 JP-A-6-166600 JP-A-6-246630 JP 2002-18711 A

The inventors of the present invention have made the horizontal cylindrical grinding device a vertical cylindrical grinding device to reduce the installation area, and a series of chamfering (grinding) processing stages into corner rough grinding processing stages (s ₂ ), a double-sided simultaneous surface grinding stage (s ₃ ) using a pair of cup wheel grinding wheels, a corner finishing cylindrical grinding stage (s ₄ ) using the outer peripheral surface of a cylindrical grinding wheel, and a pair of polishing brushes Is divided into four stages of simultaneous planar finish polishing stage (s ₅ ) using both sides, and a loading / unloading stage (s ₁ ) is added to this, so that a prismatic silicon ingot desired by a silicon substrate processing manufacturer for solar cells can be obtained. The present inventors have found that a chamfering apparatus can be provided, and have reached the present invention. The chamfering device can also be used for chamfering a cylindrical ingot for a semiconductor substrate.

The chamfering apparatus according to claim 1 of the present invention is
An index type rotary table in which an upper rotary table and a lower rotary table are integrally coupled by a hollow cylinder fixing material, and a rotation drive mechanism for rotating the hollow cylinder fixing material is provided,
On the lower rotary table of this index type rotary table, five spindle heads that rotate the center shaft by a servo motor are provided on the same circumference and at equal intervals of 72 degrees, and the hollow cylinder fixing material wall faces the upper rotary table. Five pairs of tailstocks that can be moved in the vertical direction are provided on the same circumference and at equal intervals of 72 degrees so that the center shaft of the tailstock is on the extension of the center shaft of the spindle stock. The workpiece loading / unloading stage (s ₁ ) on the index type rotary table (s ₁ ), the corner arc rough grinding stage (s ₂ ) of the workpiece, the workpiece both sides of each side surface grinding stage (s _3), the corner portions arc finish grinding stage of the work piece (s ₄₎ and the workpiece Surface finish polishing stage (s ₅₎ was divided into location index rotary table,
Grinding head that supports a cup wheel type grindstone rotatably on a grindstone axis can be moved up and down and linearly moved in the left and right direction toward the clamping mechanism of the corner circular arc rough grinding stage (s ₂ ) of the index type rotary table. A pair of grinding heads that support the cup wheel type grindstone rotatably on the grindstone axis facing the clamping mechanism of both side surface grinding stages (s ₃ ) of the workpiece of the index type rotary table can be moved up and down. The grinding head provided so as to be linearly movable in the left-right direction The cylindrical grindstone is directed toward the outer peripheral surface of the cylindrical grindstone toward the clamp mechanism of the corner arc finishing grinding stage (s ₄ ) of the workpiece of the index type rotary table. Grinding head that is rotatably supported on the grinding wheel shaft can be moved up and down. And the grinding head is provided to be linearly moved in the right direction,
The pair of polishing heads that support the polishing brush rotatably on the polishing shaft facing the clamping mechanism of the both-side flat finishing polishing stage (s ₅ ) of the workpiece of the index type rotary table can be moved up and down in the vertical direction and linearly moved in the horizontal direction. Possible polishing head,
The present invention provides a chamfering apparatus for a prismatic silicon ingot characterized in that

The invention according to claim 2 slices the periphery of the four, clamps the prismatic silicon ingot (w) with the four arc corners left in the standing direction, and goes through the following steps A) to D). A method for chamfering a prismatic silicon ingot is provided.
A) Using a cup wheel type grindstone, chamfer the corners of the four arcs by rough grinding.
B) Chamfering the four side surfaces by grinding using a cup wheel type grindstone.
C) Using the outer peripheral surface of a cylindrical grindstone, chamfering is performed on the corners of the roughly ground four arcs by finish grinding.
D) Using a polishing brush, chamfering is performed by finishing and polishing the ground four side surfaces.

Invention of Claim 3 provides the method of carrying out the chamfering process of a prismatic silicon ingot through the process of following 1)-28) using the chamfering processing apparatus (1) of Claim 1. is there.
1) The center shaft of the head stock (3ar) located at the loading / unloading stage (s ₁ ) position on the index type rotary table (2) is rotated for centering. Next, a prismatic silicon ingot (w) is placed on the center bearing base of the headstock (3ar) so that its longitudinal direction is the vertical direction, and then the center bearing base of the tailstock is lowered to form a corner. The upper and lower ends of the columnar silicon ingot are fixed (clamped).
2) The index-type rotary table (2) is rotated 72 degrees by the rotation drive mechanism (2d), and the prismatic silicon ingot (w) fixed to the clamp mechanism (3) is turned to the corner on the index-type rotary table (2). To a position on the partial arc rough grinding stage (s ₂ ).
3) The center axis of the prismatic silicon ingot is centered by rotating the center shaft of the headstock (3ar).
4) The center shaft of the headstock is rotated at a rotational speed of 10 to 300 rpm to rotate the prismatic silicon ingot (w) around its axis, while being supported by the grinding wheel shaft (4c) of the grinding head (4). The diamond cup wheel type grindstone (4f) of grinding numbers 500 to 1,200 is moved up and down to the grinding start standby position, and then the grindstone shaft (4c) is rotated around its axis at a rotational speed of 800 to 3,000 rpm. Meanwhile, the diamond cup wheel type grindstone (4f) is moved leftward so that the cutting edge of the diamond cup wheel type grindstone (4f) is brought into contact with the corner portion of the prismatic silicon ingot (w) to start cutting.
5) On the corner arc rough grinding stage (s ₂ ), the rotational movement of the prismatic silicon ingot (w) and the up-and-down movement of the rotating diamond cup wheel type grindstone (4f) from 1 to 15 mm / min. Further, R chamfering rough grinding is performed in which four corners of the prismatic silicon ingot (w) are scraped by 7 to 10 mm by the relative movement of the left side movement for cutting of 0.1 to 1 mm. In this R chamfering rough grinding process, the grinding fluid is supplied at a supply rate of 5 to 100 cc / min toward the machining work point where the prismatic silicon ingot (w) and the cutting edge of the diamond cup wheel type grindstone (4f) abut. The
6) After finishing the desired amount of R chamfering rough grinding at the four corners of the prismatic silicon ingot (w), the diamond cup wheel type grindstone (4f) is moved back to the right to move away from the prismatic silicon ingot (w). Then, the rotation of the diamond cup wheel type grindstone (4f) is stopped, and the diamond cup wheel type grindstone (4f) is moved up and down and stopped at the grinding start standby position. Meanwhile, the rotation of the center shaft of the headstock is stopped.
7) The index type rotary table (2) is rotated 72 degrees by the rotation drive mechanism (2d), and the prismatic silicon ingot (w) fixed to the clamp mechanism (3) is moved to the workpiece on the index type rotary table (2). The piece is moved to a position on both side surface grinding stages (s ₃ ).
8) After rotating the center axis of the headstock (3ar) to center the prismatic silicon ingot, the center axis rotation of the headstock (3ar) is stopped.
9) either side surface grinding stage of the workpiece _{(s 3)} diamond cup wheel type grinding wheel (5f abrasive numbered 800～1,200 for prism-shaped silicon ingot upper position (w), 5f) grindstone axis journalled to (5c, 5c) is moved up and down and stopped at the grinding start standby position, and then the grindstone shaft of the cup wheel grindstone (5f, 5f) is synchronously rotated at a rotational speed of 100 to 300 rpm.
10) The cup wheel type grindstone supported by the grindstone shaft (5c, 5c) is moved to the left or right by synchronous control and is brought into contact with both side surfaces of the prismatic silicon ingot (w). While starting the cutting, the cutting edge of the cup wheel type grindstone is moved to the side plane of the prismatic silicon ingot (w) while moving up and down 1 to 15 mm / min in the upward or downward direction of the grindstone shaft (5c, 5c). And chamfering a desired amount (0.3 to 0.8 m). During this side surface chamfering process, the grinding fluid is supplied at a rate of 20 to 1,000 cc / min toward the processing work point where the prismatic silicon ingot (w) and the cutting edge of the diamond cup wheel type grindstone (5f) abut. Supplied.
11) After finishing a desired amount of chamfering on both sides of the prismatic silicon ingot (w), the diamond cup wheel-type grindstone (5f, 5f) is retracted to the right side or the left side and the prismatic silicon ingot (w) Then, the rotation of the grindstone shaft (5c) of the diamond cup wheel type grindstone (5f, 5f) is stopped, the diamond cup wheel type grindstone (5f, 5f) is moved up and down and stopped at the grinding start standby position. In the meantime, the center axis of the spindle stock (3ar) is turned 90 degrees to center the prismatic silicon ingot (w).
12) The cup wheel type grindstone supported by the grindstone shaft (5c, 5c) is moved to the left or right by synchronous control and is brought into contact with both side surfaces of the prismatic silicon ingot (w). While starting the cutting, the cutting edge of the cup wheel type grindstone is moved to the side plane of the prismatic silicon ingot (w) while moving up and down 1 to 15 mm / min in the upward or downward direction of the grindstone shaft (5c, 5c). And chamfering a desired amount (0.3 to 0.8 mm). During the side surface chamfering process, the grinding fluid is supplied at a rate of 20 to 1,000 cc / min toward the processing point where the prismatic silicon ingot (w) and the cutting edge of the diamond cup wheel type grindstone (5f, 5f) abut. Supplied in quantity.
13) After finishing a desired amount of chamfering on both sides of the prismatic silicon ingot (w), the diamond cup wheel type grindstone (5f, 5f) is retracted to the right or left side, and the prismatic silicon ingot (w) Further away, the rotation of the grindstone shaft (5c) of the diamond cup wheel type grindstone (5f, 5f) is stopped, the grindstone shaft (5c) of the diamond cup wheel type grindstone (5f, 5f) is raised and lowered, and the grinding start standby position Stop at.
14) The index-type rotary table (2) is rotated 72 degrees by the rotation drive mechanism (2d), and the prismatic silicon ingot (w) fixed to the clamp mechanism (3) is turned to the corner on the index-type rotary table (2). Move to the partial arc finishing grinding stage (s ₄ ) position.
15) After rotating the center axis of the headstock (3ar) to center the prismatic silicon ingot, the center axis rotation of the headstock (3ar) is stopped.
16) Grinding head (6) provided on the left lateral side of the prismatic silicon ingot (w) fixed to the clamp mechanism (3) of the corner portion arc finishing grinding stage (s ₄ ) of the index type rotary table (2). The cylindrical grinding wheel (6f) supported by the grinding wheel shaft (6c) is moved upward or downward to stop at the grinding start standby position.
17) A prismatic silicon ingot (w) whose upper and lower ends are fixed by a clamping mechanism is rotated at a rotation speed of 30 to 300 rpm on the center shaft of the headstock (3ar), and the prismatic silicon ingot (w) is rotated around its axis. Rotate to On the other hand, the diamond cylindrical grindstone (6f) of the grinding number 320 to 4,000 supported by the grindstone shaft (6c) of the grinding head (6) is moved up and down to the grinding start standby position, and then the grindstone shaft (6c) is moved to the grinding wheel shaft (6c). The cylindrical grindstone (6f) is moved to the right while rotating around the axis at a rotation speed of 1,200 to 3,000 rpm, and the outer peripheral surface of the cylindrical grindstone (6f) is made of the prismatic silicon ingot (w). Start cutting by making line contact with the corner.
18) The cylindrical grindstone (6f) is moved up and down by 1 to 15 mm / min in the upward and downward directions and moved to the left, and the outer peripheral surface of the cylindrical grindstone (6f) is a prismatic silicon ingot (w) The process of making a cut in an amount of 0.05 to 0.1 mm by rubbing against the corners of the steel sheet is repeated, and a desired amount (0.2 to 0.6 mm) of R chamfer finish grinding is performed. In the four corner R chamfering finish grinding of this prismatic silicon ingot (w), the grinding fluid is directed toward the machining work point at which the corner of the prismatic silicon ingot (w) and the outer peripheral surface of the cylindrical grindstone (6f) abut. It is supplied at a supply rate of ˜2,000 cc / min.
19) After finishing the desired amount of R chamfering finish grinding at the four corners of the prismatic silicon ingot (w), the cylindrical grindstone (6f) is moved backward to the left to move away from the prismatic silicon ingot (w), and then the cylinder The rotation of the grindstone shaft (6c) of the cylindrical grindstone (6f) is stopped, the cylindrical grindstone (6f) is moved up and down and stopped at the grinding start standby position. Meanwhile, the rotation of the center shaft of the headstock (3ar) is stopped.
20) The index type rotary table (2) is rotated 72 degrees by the rotation drive mechanism (2d), and the prismatic silicon ingot (w) fixed to the clamp mechanism (3) is placed on both sides of the index type rotary table (2). Move to the surface finish polishing stage (s ₅ ) position.
21) After rotating the center axis of the headstock (3ar) to center the prismatic silicon ingot, the center axis rotation of the headstock (3ar) is stopped.
22) on both sides flat finish polishing stages of the work piece _{(s 5)} polishing brush for prism-shaped silicon ingot upper position (w) (7f, 7f) polishing axis journalled a (7c, polishing start waiting position by lifting the 7c) Then, the grindstone shaft of the polishing brush (7f, 7f) is synchronously rotated at a rotational speed of 500 to 700 rpm.
23) The polishing brush string 7f, 7f supported on the polishing shaft (7c, 7c) is moved to the left or right in a synchronized manner and brought into contact with both side planes of the prismatic silicon ingot (w) so that the string of the polishing brush A string of polishing brushes while starting cutting with abrasive grains adhering to (monofilament) and moving up and down 120 to 1,000 mm / min in the upward or downward direction of the polishing shaft (7c, 7c) Abrasive particles adhering to the side surface of the prismatic silicon ingot (w) are rubbed against each other and repeated incision of 0.05 to 0.1 mm to chamfer the desired amount (0.1 to 0.2 mm). I do. In the side surface flat finishing polishing process, the polishing liquid is supplied at a supply rate of 50 to 1,000 cc / min toward a processing work point at which the prismatic silicon ingot (w) and the polishing brush (7f) abut.
24) After finishing a desired amount of chamfering on both sides of the prismatic silicon ingot (w), the polishing brushes (7f, 7f) are retracted to the right or left to move away from the prismatic silicon ingot (w). Next, the rotation of the polishing shaft (7c) of the polishing brush (7f, 7f) is stopped, and the polishing brush (7f, 7f) is lifted and stopped at the polishing start standby position. In the meantime, the center axis of the spindle stock (3ar) is turned 90 degrees to center the prismatic silicon ingot (w).
25) The polishing brush supported by the polishing shaft (7c, 7) is synchronously moved to the left or right to contact the both side planes of the prismatic silicon ingot (w) and adhere to the string (monofilament) of the polishing brush. The cutting brush is moved up and down and the polishing brush is moved up and down 120 to 1,000 mm / min while the polishing brush is moved to a prismatic silicon ingot (w ) Is repeated by rubbing on the side plane of 0.05) to 0.1 mm to perform a desired amount (0.1 to 0.2 mm) of chamfering. In the side surface flat chamfering polishing step, the polishing liquid is supplied at a supply rate of 50 to 1,000 cc / min toward a processing work point where the prismatic silicon ingot (w) and the polishing brush (7f) come into contact.
26) After finishing a desired amount of side surface flat chamfering polishing on both sides of the prismatic silicon ingot (w), the polishing brushes (7f, 7f) are retracted to the right or left to make the prismatic silicon ingot (w) Then, the polishing shaft (7c, 7c) of the polishing brush (7f, 7f) is moved up and down and stopped at the polishing start standby position.
27) The index-type rotary table (2) is rotated 72 degrees by the rotation drive mechanism (2d) or rotated 288 degrees in the reverse direction, and the prismatic silicon ingot (w) fixed to the clamp mechanism (3) is index-type Move to the loading / unloading stage (s ₁ ) position on the rotary table (2).
28) The center shaft of the tailstock at the loading / unloading stage (s ₁ ) position is moved upward, and the cradle provided at the lower end of the center shaft is moved away from the upper end surface of the prismatic silicon ingot (w). Next, the chamfered prismatic silicon ingot (w) is removed from the headstock (3ar).

  The chamfering processing apparatus for a prismatic silicon ingot of the present invention uses a cup wheel type grindstone, a cylindrical grindstone, and a polishing brush as a chamfering cutting tool (tool). Therefore, at the time of rubbing between the prismatic silicon ingot and the chamfering cutting tool. Since the heat generation is suppressed to a low level and the residual thermal strain on the prismatic silicon ingot is extremely small, a smooth chamfered surface with a small surface waviness (surface roughness as small as 1 μm or less) can be obtained. Moreover, the installation area of the chamfering apparatus can be reduced by adopting a structure in which five clamp mechanisms including a headstock and a tailstock are provided in the index type rotary table in the vertical direction.

The method for chamfering a prismatic silicon ingot according to the present invention includes chamfering a prismatic silicon ingot, R-chamfering rough grinding (operation A) at the corner of the prismatic silicon ingot, and rough surface chamfering on the four sides of the prismatic silicon ingot. It will be carried out in four operations: machining (operation B), round chamfering finishing grinding of the corners of the prismatic silicon ingot (operation C), and planar finishing chamfering (operation D) of the four sides of the prismatic silicon ingot using a polishing brush. Therefore, four of the five prismatic silicon ingots clamped on the index type rotary table can be engaged in the chamfering work at the same time, so the chamfering of one prismatic silicon ingot is completed. During rough surface chamfering on the four sides of a prismatic silicon ingot where the throughput time is the rate-limiting work process And becomes a total time of 72-degree rotation time of the index rotary table, it was shorter than the throughput using conventional horizontal chamfering device. In addition, the automatic loader machine or the manual attachment / detachment to / from the clamping mechanism of the prismatic silicon ingot at the time of chamfering is only required once. Therefore, it is possible to produce a chamfering of a prismatic single crystal silicon ingot having a side of 156 mm and a height of 250 mm and cut with a band saw leaving four corners in four corners in a throughput processing time of about 41 minutes. A single-crystal silicon ingot that is chamfered can be produced with a throughput processing time of about 1/2 (about 41 minutes) compared to about 95 minutes of the throughput processing time of chamfering with a chamfering device installed in parallel with multiple devices. . Throughput processing time for chamfering a prismatic silicon ingot having a side of 156 mm and a height of 500 mm can be performed in about 81 minutes.

FIG. 1 is a plan view of the chamfering apparatus as viewed from above. FIG. 2 is a front view of the chamfering apparatus. FIG. 3 is a rear view of the chamfering apparatus. FIG. 4 is a bird's-eye view of the chamfering apparatus as viewed from the front left direction. FIG. 5 is a bird's-eye view of the chamfering apparatus as viewed from the back right direction. FIG. 6 is an explanatory diagram showing a positional relationship between a workpiece and a grindstone in a chamfering stage of a prismatic silicon ingot.

  In the chamfering apparatus (1) of the present invention, as shown in FIGS. 1 to 6, the upper rotary table (2a) and the lower rotary table (2b) are integrally coupled by a hollow cylinder fixing material (2c), An index type rotary table (2) provided with a rotary shaft (2d) in a hollow cylinder fixing material and provided with a rotary shaft drive mechanism for rotating the rotary shaft by a servo motor (not shown). Five spindle heads (3ar, 3br, 3cr, 3dr, 3er) that rotate the center shaft by a servo motor (not shown) are attached to the lower rotary table (2b) of the index type rotary table (2) on the same circumference. A tailstock which is provided on the top and at an equal interval of 72 degrees and is movable in the vertical direction toward the upper rotary table (2a) on the wall of the hollow cylinder fixing member (2C) Five units (3af, 3bf, 3cf, 3df, 3ef) are provided on the same circumference and at an equal interval of 72 degrees so that the center shaft of the tailstock is located on the extension of the center shaft of the headstock. The clamping mechanism (3, 3, 3, 3, 3) is provided.

As shown in FIG. 1, the positions of the five pairs of clamping mechanisms (3, 3, 3, 3, 3) are determined by the loading / unloading stage (s) of the workpiece (w) on the index type rotary table (2). _1), the corner portions arc rough grinding stage of the work piece (s _2), each side surface grinding stage of the workpiece (s _3), the corner portions arc finish grinding stage of the work piece (s ₄₎ and both side planes final polishing of the workpiece Divide into stage (s ₅ ) positions.

  As shown in FIG. 6, at the upper end of the center shaft of the headstock (3ar) of the clamp mechanism (3), a cushion made of alicyclic hydrocarbon epoxy resin, vulcanized rubber, unsaturated polyester resin impregnated felt A pedestal (3ad) with good performance is provided, and a pedestal (3ad) of the same type as above is also provided at the lower end of the center shaft of the tailstock (3af). It is prevented from being damaged by the supporting stress. The base (3x) for fixing the tailstock (3af) can slide up and down on the guide rail (3y) by driving the motor (3xm).

As shown in FIGS. 1, 2 and 4, the index type rotary table (2) has a base (B) facing the clamping mechanism (3) of the corner arc rough grinding stage (s ₂ ) on the front right side front side of the index type rotary table (2). ) Is provided with a column (4b) standing upright, and a guide guide (4k) and a sliding body (4s) sliding up and down on the guide guide are provided on the rear surface. The sliding body (4s) can be moved up and down by the vertical movement of a screwed body that is screwed into a rotating ball screw in response to the rotation of the servo motor (4m). Another guide guide (4x) is provided laterally on the front surface of the sliding body (4s), and a grindstone shaft fixing box slide (4y) is provided in front thereof. The linear movement mechanism (4h) for moving the grindstone shaft fixing box slide in the left-right direction includes a servo motor, a ball screw that receives the rotational drive, and a screwed body screwed by the ball screw. The screwed body is fixed to the back surface of the grindstone shaft fixing box slide (4y).

  A grindstone shaft (4c) box (4z) for supporting the cup wheel type grindstone (4f) is provided on the front surface of the grindstone shaft fixed box slide (4y), and the grindstone shaft (4c) rotates the grindstone shaft (4c). It is coupled to a rotation mechanism (4g) including a servo motor to be driven. Therefore, the vertical movement of the cup wheel type grindstone (4f) supported by the grindstone shaft (4c) is performed by the rotational drive of the servo motor (4m), and the left and right movement of the cup wheel type grindstone (4f) is This is performed by rotating the servo motor of the linear moving mechanism (4h). The elevating mechanism and the linear moving mechanism may be driven by a linear motor in which a stationary electromagnetic element is provided in the guide guide and a free electromagnetic element is provided in the sliding body.

A tool that moves in the front-rear direction by a linear moving mechanism (5h) facing the clamping mechanism (3) of the both sides rough grinding stage (s ₃ ) of the workpiece on the right side rear side of the back of the index type rotary table (2) A table (5a) is provided, a column (5b) is erected on the tool table (5a), and a grindstone shaft fixing plate (5e) is provided on the front surface of the column so as to be vertically movable by an elevating mechanism (5d). wherein on each side of the front surface grinding stage _{(s 3)} of the clamping mechanism (3), respectively a cup wheel type grinding wheel (5f, 5f) to the left and right sides of the wheel shaft so that the blade tip is opposed to the plate (5e) (5c, 5c A grinding head that is provided with a grinding wheel shaft fixing plate that can move in the left-right direction and that supports a pair of cup wheel type grinding wheels (5f, 5f) on the grinding wheel shaft (5c, 5c). (5, 5) and a rotational drive mechanism (5g, 5g) for the grindstone shaft (5c, 5c) are provided.

A tool table (5a) that is moved in the front-rear direction by the workpiece linear movement mechanism (guide 5n and servo motor 5m) is provided on the base (B), and the column (5b) is erected on the tool table (5a). , wheel spindle fixing plate to the column front by (5e) a lifting mechanism (5d) provided vertically movably, the clamp mechanism (3) of the two side surface grinding stage in front of the wheel spindle fixing plate (5e) (s ₃₎ A grindstone shaft fixing plate (5k, 5k) movable in the left-right direction for fixing the grindstone shaft (5c, 5c) so that the cutting edges of the cup wheel type grindstone (5f, 5f) face each other on both the left and right sides, A grinding head (5, 5) in which a pair of cup wheel type grindstones (5f, 5f) is supported on the grindstone shaft (5c, 5c) and a rotational drive mechanism (5g, 5g) of the grindstone shaft (5c, 5c). Establishment . The grindstone shaft fixing plates (5k, 5k) can be moved in the left-right direction by the rotational drive of servo motors (5h, 5h). The tool table (5a) transmits a moving force in the front-rear direction of a screwed body that is screwed to a rotating ball screw in response to the rotational drive of a servo motor (5m) to the tool table (5a), so that the workpiece (w) On the other hand, it can slide on the guide (5n) in the front-rear direction.

  The cup wheel type grindstone (4f, 5f) is a lower part of a bottomed cylindrical grindstone base metal disclosed in, for example, Japanese Patent Laid-Open Nos. 9-38866, 2000-94342, and 2004-167617. A cup wheel type grindstone in which a large number of grindstone blades are annularly arranged on the annular ring with a gap interval at which the grinding fluid is dissipated, and the grinding fluid supplied to the inside of the base metal is preferably dissipated from the gap. The diameter of the annular grindstone blade of the cup wheel type grindstone (4f, 5f) is preferably 0.8 to 1.5 times the length of one side of the prismatic silicon ingot. The ring wheel of the cup wheel type grindstone (4f) is a diamond resin bond grindstone with a grinding number of 500 to 1,200 or a diamond vitrified bond grindstone, and the ring grindstone blade of a cup wheel type grindstone (5f) is a grindstone of 800. A diamond resin bond grindstone of No. 1,200, a diamond vitrified bond grindstone, or a diamond metal bond grindstone is preferable.

The index-type rotary table (2) can be reciprocated in the left-right direction by the linear movement mechanism (6h) facing the clamping mechanism (3) of the both sides rough grinding stage (s ₃ ) on the left side rear side of the back side of the index type rotary table (2) A grindstone shaft (6c) that supports a cylindrical grindstone (6f) on the right side surface of a column (6b) provided upright on a simple tool table (6a), and is movable up and down by an elevating mechanism (6d); A grinding head (6) provided with a grindstone shaft (6c) rotatably by a rotation drive mechanism (6g) is provided.

  The linear moving mechanism (6h) includes a ball screw rotated by a servo motor (6hM), a guide guide (6hG), and a screw fixed to the bottom surface of a tool table (6a) that slides on the guide guide in the left-right direction. Composed of union. The linear moving mechanism (6h) may be a linear motor drive in which a stationary electromagnetic element is provided in the guide guide and a free electromagnetic element is provided on the bottom surface of the tool table (6a).

  The cylindrical grindstone (6f) preferably has, for example, a cylinder height of 25 to 100 mm and a cylinder diameter of 0.8 to 1.5 times the length of one side of the prismatic silicon ingot. As a grindstone material, a diamond vitrified bond grindstone having a grind number of 1,200 to 4,000, a diamond resin bond grindstone, or a diamond metal bond grindstone is used. Further, diamond abrasive grains having abrasive numbers 320 to 1,200 are melt-kneaded in a thermoplastic resin such as a polyamide resin, a polyester resin, or a polyvinyl alcohol resin in an amount of 15 to 35% by weight. A diamond disk brush (explained in Non-Patent Document 2, for example) that is extruded into a string or monofilament shape and cut to a length of 10 to 20 mm to obtain brush hair, and this brush hair is planted on the outer periphery of the cylindrical substrate with an adhesive. SK diamond disk brush (trade name) manufactured by Showa Industry Co., Ltd. can also be used.

A tool table that is moved in the front-rear direction by a linear moving mechanism (7h) facing the clamping mechanism (3) of the both-side flat finishing polishing stage (s ₅ ) of the workpiece on the front left side and front side of the index type rotary table (2). (7a) is provided, the column (7b) is erected on the tool table (7a), and a polishing shaft fixing plate (7e) is provided on the front surface of the column so as to be vertically movable by a lifting mechanism (7d). as attached to Firamonto each polishing brush to the left and right sides of the clamping mechanism (3) of the the front of the (7e) on both sides flat finish polishing stage (s ₅₎ (7f, 7f) (containing) the abrasive grains are opposed A polishing shaft fixing plate movable in the left-right direction for fixing the polishing shaft (7c, 7c) is provided, and a pair of cup wheel type polishing bras is provided on the polishing shaft (7c, 7c). A polishing head (7, 7) for bearing the support (7f, 7f) and a rotation drive mechanism (7g, 7g) for the polishing shaft (7c, 7) are provided.

  As the polishing brush (7f), diamond abrasive grains having an abrasive number of 320 to 1,200 were melt-kneaded in a thermoplastic resin such as polyamide resin, polyester resin, or polyvinyl alcohol resin in an amount of 15 to 35% by weight. Extruded in a 5 to 1.5 mm string or monofilament shape and cut to a length of 5 to 12 mm to obtain brush hairs, and the brush hairs are bundled in a cylindrical shape with an adhesive (Japanese Patent Laid-Open No. 2000-271877, No. 2007-38328), brush hairs are planted on an annular pedestal at a uniform height with an adhesive (see FIG. 2 or FIG. 6 of JP-A-2002-307308, or disclosed in Non-Patent Document 2). SK type high-density diamond cup brush (trade name) from Showa Industry Co., Ltd. Cup wheel type abrasive brushes planted in a cup shape at a Tsu bets spacing can be used.

  As the polishing liquid, pure water, colloidal silica water dispersion, ceria water dispersion, SC-1 liquid, SC-2 liquid, or pure water and these water dispersion or polishing liquid are used in combination. In the chamfering method of the present invention, since the rough grinding of the R-surface corner portion of the ingot is a rate-limiting step, it is preferable to use only pure water from the viewpoint of environmental water treatment.

As shown in FIG. 6, the four-corner arc corner (R) portion chamfering and side chamfering of the prismatic silicon ingot are performed by attaching / detaching the prismatic silicon ingot at the loading / unloading stage (s ₁ ), as shown in FIG. 72 degree rotation work of the table, R round grinding of the four corners of the prismatic silicon ingot at the corner circular arc rough grinding stage (s ₂ ) of the workpiece, 72 degree rotation work of the index type rotary table, both side surface grinding stage of the workpiece Surface grinding of the four sides of the prismatic silicon ingot at (s ₃ ), 72-degree rotation of the index type rotary table, R finishing of the four corners of the prismatic silicon ingot at the corner arc finishing grinding stage (s ₄ ) of the workpiece Grinding, index type rotary table 72 degree rotation operations are performed by repeating planar finish polishing prismatic silicon ingot four side surfaces on both sides planar finish polishing stages of the work piece (s _5), and a 72-degree rotation work of the index rotary table. If necessary, centering work is performed at each stage (s ₁ , s ₂ , s ₃ , s ₄ , s ₅ ) by rotating the center shaft of the headstock. It should be noted that the loading of the ingot in the S ₁ stage of ingot by hand, carry-out, the centering work, it takes about 10 minutes. If an autoloader is used, these work times can be further shortened.

  Specifically, using the chamfering apparatus of the present invention, the periphery of 4 as a workpiece is sliced, and the prismatic silicon ingot (w) with the four arc corners left is removed using the cup wheel type grindstone. Working step (A) for chamfering the part by rough grinding, working step (B) for chamfering the four side surfaces by rough grinding using a cup wheel type grindstone, and using the outer peripheral surface of a cylindrical grindstone, Working process (C) for chamfering the grounded four arc corners by finish grinding, and working process (D) for chamfering the ground four-sided planes by polishing using a polishing brush The step of chamfering the ingot through the steps is performed through the following steps 1) to 28).

First, in the loading / unloading stage (s ₁ ), the following operation is performed.

1) Remove the chamfered prismatic silicon ingot on the index-type rotary table (2) from the headstock with an automatic loader or manually, and then rotate the center shaft of the headstock (3ar) to center the Place the prismatic silicon ingot on the center bearing base of the headstock (3ar) so that the longitudinal direction of the prismatic silicon ingot (w) is vertical, and then lower the center bearing base of the tailstock The upper and lower ends of the prismatic silicon ingot are fixed (clamped).

2) The index-type rotary table (2) is rotated 72 degrees by the rotation drive mechanism (2d), and the prismatic silicon ingot (w) fixed to the clamp mechanism (3) is turned to the corner on the index-type rotary table (2). To a position on the partial arc rough grinding stage (s ₂ ).

Next, in the corner portion arc rough grinding stage (s ₂ ), the following operation (step A) is performed.

3) The center axis of the prismatic silicon ingot is centered by rotating the center shaft of the headstock (3ar). When the chamfering software program stores the corner (R) part of the prismatic silicon ingot so that it is at the fixed position closest to the cutting edge of the cup wheel grindstone, the center axis of the headstock (3ar) rotates. Is 45 degrees and centering is performed. When the side surface of the prismatic silicon ingot is stored in the chamfering software program so that the side surface is closest to the cutting edge of the cup wheel grindstone, this centering operation may be omitted.

4) The center shaft of the headstock is rotated at a rotational speed of 10 to 300 rpm to rotate the prismatic silicon ingot (w) around its axis, while being supported by the grinding wheel shaft (4c) of the grinding head (4). The diamond cup wheel type grindstone (4f) of grinding numbers 500 to 1,200 is moved up and down to the grinding start standby position, and then the grindstone shaft (4c) is rotated around its axis at a rotational speed of 800 to 3,000 rpm. Meanwhile, the diamond cup wheel type grindstone (4f) is moved leftward so that the cutting edge of the diamond cup wheel type grindstone (4f) is brought into contact with the corner portion of the prismatic silicon ingot (w) to start cutting.

5) On the corner arc rough grinding stage (s ₂ ), the rotational movement of the prismatic silicon ingot (w) and the up-and-down movement of the rotating diamond cup wheel type grindstone (4f) from 1 to 15 mm / min. Then, rough chamfering is performed in which the four corners of the prismatic silicon ingot (w) are scraped by 7 to 10 mm by the relative movement of the left side movement for cutting of 0.1 to 1 mm. During this rough chamfering process, the grinding fluid is supplied at a supply rate of 5 to 100 cc / min toward the processing work point where the prismatic silicon ingot (w) and the cutting edge of the diamond cup wheel type grindstone (4f) abut. .

6) After finishing a desired amount of R chamfering at the four corners of the prismatic silicon ingot (w), the diamond cup wheel type grindstone (4f) is moved back to the right to move away from the prismatic silicon ingot (w), and then diamond The rotation of the cup wheel type grindstone (4f) is stopped, and the diamond cup wheel type grindstone (4f) is moved up and down and stopped at the grinding start standby position. Meanwhile, the rotation of the center shaft of the headstock is stopped.

7) The index type rotary table (2) is rotated 72 degrees by the rotation drive mechanism (2d), and the prismatic silicon ingot (w) fixed to the clamp mechanism (3) is moved to the workpiece on the index type rotary table (2). The piece is moved to a position on both side surface grinding stages (s ₃ ).

Subsequently, the following work (step B) is performed at the both side surface grinding stage (s ₃ ) of the workpiece.

8) After rotating the center axis of the headstock (3ar) to center the prismatic silicon ingot, the center axis rotation of the headstock (3ar) is stopped. In the centering operation, when the center axis of the headstock (3ar) is rotated 45 degrees in the step 3), the centering work is performed by rotating the center axis of the headstock (3ar) by 45 degrees. When the rotation or centering is not performed, this centering operation may be omitted.

9) either side surface grinding stage of the workpiece _{(s 3)} diamond cup wheel type grinding wheel (5f abrasive numbered 800～1,200 for prism-shaped silicon ingot upper position (w), 5f) grindstone axis journalled to (5c, 5c) is moved up and down and stopped at the grinding start standby position, and then the grindstone shaft of the cup wheel grindstone (5f, 5f) is synchronously rotated at a rotational speed of 100 to 300 rpm.

10) The cup wheel type grindstone supported by the grindstone shaft (5c, 5c) is moved to the left or right by synchronous control and is brought into contact with both side surfaces of the prismatic silicon ingot (w). While starting the cutting, the cutting edge of the cup wheel type grindstone is moved to the side plane of the prismatic silicon ingot (w) while moving up and down 1 to 15 mm / min in the upward or downward direction of the grindstone shaft (5c, 5c). And chamfering a desired amount (0.3 to 0.8 mm). During this side surface chamfering process, the grinding fluid is supplied at a rate of 20 to 1,000 cc / min toward the processing work point where the prismatic silicon ingot (w) and the cutting edge of the diamond cup wheel type grindstone (5f) abut. Supplied.

11) After finishing a desired amount of chamfering on both sides of the prismatic silicon ingot (w), the diamond cup wheel-type grindstone (5f, 5f) is retracted to the right side or the left side and the prismatic silicon ingot (w) Then, the rotation of the grindstone shaft (5c) of the diamond cup wheel type grindstone (5f, 5f) is stopped, the diamond cup wheel type grindstone (5f, 5f) is moved up and down and stopped at the grinding start standby position. In the meantime, the center shaft of the headstock (3ar) is turned 90 degrees to center the prismatic silicon ingot (w).

12) The cup wheel type grindstone supported by the grindstone shaft (5c, 5c) is moved to the left or right by synchronous control and is brought into contact with both side surfaces of the prismatic silicon ingot (w). While starting the cutting, the cutting edge of the cup wheel type grindstone is moved to the side plane of the prismatic silicon ingot (w) while moving up and down 1 to 15 mm / min in the upward or downward direction of the grindstone shaft (5c, 5c). And chamfering a desired amount (0.3 to 0.8 mm). During this side surface chamfering process, the grinding fluid is supplied at a rate of 20 to 1,000 cc / min toward the processing work point where the prismatic silicon ingot (w) and the cutting edge of the diamond cup wheel type grindstone (5f) abut. Supplied.

13) After finishing a desired amount of chamfering on both sides of the prismatic silicon ingot (w), the diamond cup wheel type grindstone (5f, 5f) is retracted to the right or left side, and the prismatic silicon ingot (w) Further away, the rotation of the grindstone shaft (5c) of the diamond cup wheel type grindstone (5f, 5f) is stopped, the grindstone shaft (5c) of the diamond cup wheel type grindstone (5f, 5f) is raised and lowered, and the grinding start standby position Stop at.

14) The index-type rotary table (2) is rotated 72 degrees by the rotation drive mechanism (2d), and the prismatic silicon ingot (w) fixed to the clamp mechanism (3) is turned to the corner on the index-type rotary table (2). Move to the partial arc finishing grinding stage (s ₄ ) position.

Subsequently, the following work (process C) is performed in the corner arc finishing grinding stage (s ₄ ) of the workpiece.

15) The center shaft of the headstock (3ar) is stopped after rotating the center shaft of the headstock (3ar) to center the prismatic silicon ingot. In the centering operation, when the center axis of the headstock (3ar) is rotated 45 degrees in the step 8), the centering work is performed by rotating the center axis of the headstock (3ar) by 45 degrees. When the rotation or centering is not performed, this centering operation may be omitted.

16) Grinding head (6) provided on the left lateral side of the prismatic silicon ingot (w) fixed to the clamp mechanism (3) of the corner portion arc finishing grinding stage (s ₄ ) of the index type rotary table (2). The cylindrical grinding wheel (6f) supported by the grinding wheel shaft (6c) is moved upward or downward to stop at the grinding start standby position.

17) A prismatic silicon ingot (w) whose upper and lower ends are fixed by a clamping mechanism is rotated at a rotation speed of 30 to 300 rpm on the center shaft of the headstock (3ar), and the prismatic silicon ingot (w) is rotated around its axis. Rotate to On the other hand, the diamond cylindrical grindstone (6f) of the grinding number 320 to 4,000 supported by the grindstone shaft (6c) of the grinding head (6) is moved up and down to the grinding start standby position, and then the grindstone shaft (6c) is moved to the grinding wheel shaft (6c). The cylindrical grindstone (6f) is moved to the right while rotating around the axis at a rotation speed of 1,200 to 3,000 rpm, and the outer peripheral surface of the cylindrical grindstone (6f) is made of the prismatic silicon ingot (w). Start cutting by making line contact with the corner.

18) The cylindrical grindstone (6f) is moved up and down by 1 to 15 mm / min in the upward and downward directions and moved to the left, and the outer peripheral surface of the cylindrical grindstone (6f) is a prismatic silicon ingot (w) The process of making a cut in an amount of 0.05 to 0.1 mm by rubbing against the corners of the steel sheet is repeated, and a desired amount (0.2 to 0.6 mm) of R chamfer finish grinding is performed. In the four corner R chamfering process of the prismatic silicon ingot (w), the grinding fluid is directed toward the machining work point where the corner of the prismatic silicon ingot (w) contacts the outer peripheral surface of the cylindrical grindstone (6f). It is supplied at a supply rate of ˜2,000 cc / min.

19) After finishing the desired amount of rounded chamfering at the four corners of the prismatic silicon ingot (w), the cylindrical grindstone (6f) is moved backward to the left to move away from the prismatic silicon ingot (w), and then the cylinder The rotation of the grindstone shaft (6c) of the cylindrical grindstone (6f) is stopped, the cylindrical grindstone (6f) is moved up and down and stopped at the grinding start standby position. Meanwhile, the rotation of the center shaft of the headstock (3ar) is stopped.

20) The index type rotary table (2) is rotated 72 degrees by the rotation drive mechanism (2d), and the prismatic silicon ingot (w) fixed to the clamp mechanism (3) is placed on both sides of the index type rotary table (2). It moves to the surface simultaneous planar finish polishing stage (s ₅ ) position.

21) After rotating the center axis of the headstock (3ar) to center the prismatic silicon ingot, the center axis rotation of the headstock (3ar) is stopped.

22) on both sides flat finish polishing stages of the work piece _{(s 5)} of the abrasive numbered 320～1,200 for prism-shaped silicon ingot upper position (w) Diamond bristles cup wheel type abrasive brush (7f, 7f) and for journalled polishing The shaft (7c, 7c) is moved up and down and stopped at the polishing start standby position, and then the polishing shaft of the polishing brush (7f, 7f) is rotated synchronously at a rotational speed of 120 to 350 rpm.

Subsequently, the following work (step E) is performed in the both-side flat finish polishing stage (s ₅ ) of the workpiece.

23) The polishing brushes (7f, 7f) supported by the polishing shafts (7c, 7c) are moved synchronously to the left or right to bring the brush bristles of the polishing brush into contact with both side surfaces of the prismatic silicon ingot (w). In addition to starting cutting with brush bristles, the brush bristles of the polishing brush are moved up and down by 1-15 mm / min in the upward or downward direction of the polishing shaft (7c, 7c) while the prismatic silicon ingot (w ) Is repeated by rubbing on the side plane of 0.05) to 0.1 mm to perform a desired amount (0.1 to 0.2 mm) of chamfering. In the side surface finishing polishing process, the polishing liquid is supplied at a supply rate of 50 to 1,000 cc / min toward a processing work point where the prismatic silicon ingot (w) and the brush bristles of the polishing brush come into contact with each other. .

24) After finishing a desired amount of surface finish polishing on both sides of the prismatic silicon ingot (w), the polishing brushes (7f, 7f) are retracted to the right or left to move away from the prismatic silicon ingot (w). Then, the rotation of the polishing shaft (7c, 7c) of the polishing brush (7f, 7f) is stopped, and the polishing brush (7f, 7f) is lifted and stopped at the polishing start standby position. In the meantime, the center shaft of the headstock (3ar) is turned 90 degrees to center the prismatic silicon ingot (w).

25) The polishing brush (7f, 7f) supported by the polishing shaft (7c, 7c) is moved to the left or right in synchronization and brought into contact with both side surfaces of the prismatic silicon ingot (w) to make the brush of the polishing brush While starting to cut with bristles, the brush bristles of the polishing brush are moved to the side of the prismatic silicon ingot (w) while moving up and down the polishing shaft (7c, 7c) by 1-15 mm / min. The chamfering process is carried out by a desired amount (0.1 to 0.2 mm) by repeatedly rubbing on a flat surface and repeating a cut of 0.05 to 0.1 mm. During the side surface finish polishing process, the supply amount of the polishing liquid is 50 to 1,000 cc / min toward the working point where the prismatic silicon ingot (w) and the brush bristles of the polishing brush (7f, 7f) contact each other. Supplied in.

26) After finishing a desired amount of chamfering on both sides of the prismatic silicon ingot (w), the polishing brush (7f, 7f) is moved back to the right or left to move away from the prismatic silicon ingot (w). Next, the polishing shaft (7c, 7c) of the polishing brush (7f, 7f) is moved up and down and stopped at the polishing start standby position.

27) The index-type rotary table (2) is rotated 72 degrees by the rotation drive mechanism (2d) or rotated 288 degrees in the reverse direction, and the prismatic silicon ingot (w) fixed to the clamp mechanism (3) is index-type Move to the loading / unloading stage (s ₁ ) position on the rotary table (2).

Subsequently, the following operations are performed in the workpiece loading / unloading stage (s ₁ ).

28) The center shaft of the tailstock at the loading / unloading stage (s ₁ ) position is moved upward, and the cradle provided at the lower end of the center shaft is moved away from the upper end surface of the prismatic silicon ingot (w). Next, the chamfered prismatic silicon ingot (w) is removed from the headstock (3ar).

Subsequently, the process returns to the fixing operation (loading) of the new prismatic silicon ingot to the clamping mechanism in the loading / unloading stage (s ₁ ) in the step 1) described above.

29) Hereinafter, the operations in steps 2) to 28) are continuously performed. During this continuous chamfering process, another loading / unloading stage (s ₁ ), a corner circular arc rough grinding stage (s ₂ ) of the workpiece, both side surface grinding stages (s ₃ ) of the workpiece, In the corner arc finishing grinding stage (s ₄ ) and the both-side planar finishing polishing stage (s ₅ ) of the workpiece, unloading / loading of the workpiece, R-chamfering rough grinding of the prismatic silicon ingot, both sides of the prismatic silicon ingot Surface grinding, R-chamfer finish grinding of the prismatic silicon ingot, and both-side planar finishing polishing of the prismatic silicon ingot are performed.

  Using the chamfering apparatus shown in FIG. 1, pure water is used as the grinding fluid and the polishing fluid, and the workpiece (w) has a side of 156 mm, a height of 486 mm, and a prismatic unit that has been cut leaving four corners. The chamfering of the crystalline silicon ingot was carried out through the steps 1) to 28). The throughput processing time was about 80 minutes. The average roughness of the chamfered processed surface was 0.23 μm.

The chamfering of the R part rough grinding stage (s ₂ ) with a machining allowance of 7.5 mm involves rotating the workpiece (w) at a rotational speed of 120 rpm, a diameter of 200 mm, and a diamond cup wheel type grindstone (4f) having a grinding number of 800. Was 2,000 rpm and the lifting speed was 3 mm / min over 80 minutes.

In the chamfering of the 0.6 mm machining allowance of the both side surface grinding stage (s ₃ ), the workpiece (w) is not rotated, and the number of revolutions of the diamond cup wheel type grindstone (5f) with the grinding number 1,500 is 2 It was carried out over 68 minutes at a speed of 5 mm / min.

The chamfering of the R part finish grinding stage (s ₄ ) with a 0.4 mm machining allowance is a diamond vitrified bond cylindrical shape having a workpiece (w) rotational speed of 150 rpm, a diameter of 200 mm, a height of 35 mm, and an abrasive number of 1,200. The rotation speed of the grindstone (6f) was 2,000 rpm, and the raising / lowering speed was 8 mm / min over 15 minutes.

The chamfering process of 0.1 mm removal allowance of the both-side flat finishing polishing stage (s ₅ ) does not rotate the workpiece (w), and the nylon 6 brush hair whose diamond abrasive grain content of the abrasive number 380 is 28% by weight The cup wheel type polishing brush (7f, 7f) in which hair was planted on an annular pedestal was rotated at 1,000 rpm and the lifting speed was 15 mm / min over 60 minutes.

  When this chamfered prismatic silicon ingot was cut to a thickness of 200 μm with a wire cut saw, no chipping was observed and no defective product was found.

The chamfering apparatus of the present invention can also be used for chamfering a side peripheral surface of a cylindrical silicon ingot for a semiconductor substrate. In the chamfering process, both the side surface simultaneous surface grinding process stage (s ₃ ) using a pair of cup wheel type grindstones and the both side surface simultaneous surface finishing polishing process stage (s ₅ ) using a pair of polishing brushes depend on the headstock. The ingot is rotated. Therefore, when chamfering of the silicon substrate for solar cells is free, it can be used for chamfering of a cylindrical silicon ingot for a semiconductor substrate.

  The chamfering processing throughput time of the prismatic silicon ingot can be performed in about half that of the conventional machine, and the chamfering processing apparatus is a vertical index type apparatus, so that it can be designed without increasing the installation area.

DESCRIPTION OF SYMBOLS 1 Chamfering processing apparatus w Square columnar silicon ingot 2 Index type rotary table s ₁ Loading / unloading stage s ₂ Corner circular arc rough grinding stage s ₃ Work piece side surface grinding stage s ₄ Work piece corner circular arc finishing Grinding stage s ₅ Both-side planar finish polishing stage 3 Workpiece clamp mechanism 3ar Main shaft 3af Tailstock 4 Grinding head 4c Grinding wheel shaft 4f Diamond cup wheel type grinding wheel 5 Grinding head 5c Grinding wheel shaft 5f Diamond cup wheel type grinding wheel 6 Grinding head 6c Grinding wheel shaft 6f Cylindrical grinding wheel 7 Polishing head 7c Polishing shaft 7f Diamond abrasive grain containing brush bristle cup wheel type polishing brush

Claims (3)

An index type rotary table in which an upper rotary table and a lower rotary table are integrally coupled by a hollow cylinder fixing material, and a rotation drive mechanism for rotating the hollow cylinder fixing material is provided,
On the lower rotary table of this index type rotary table, five spindle heads that rotate the center shaft by a servo motor are provided on the same circumference and at equal intervals of 72 degrees, and the hollow cylinder fixing material wall faces the upper rotary table. Five pairs of tailstocks that can be moved in the vertical direction are provided on the same circumference and at equal intervals of 72 degrees so that the center shaft of the tailstock is on the extension of the center shaft of the spindle stock. The workpiece loading / unloading stage (s ₁ ) on the index type rotary table (s ₁ ), the corner arc rough grinding stage (s ₂ ) of the workpiece, the workpiece both sides of each side surface grinding stage (s _3), the corner portions arc finish grinding stage of the work piece (s ₄₎ and the workpiece Surface finish polishing stage (s ₅₎ was divided into location index rotary table,
Grinding head that supports a cup wheel type grindstone rotatably on a grindstone axis can be moved up and down and linearly moved in the left and right direction toward the clamping mechanism of the corner circular arc rough grinding stage (s ₂ ) of the index type rotary table. A pair of grinding heads that support the cup wheel type grindstone rotatably on the grindstone shaft facing the clamping mechanism of both side surface grinding stage (s ₃ ) of the workpiece of the index type rotary table can be moved up and down. The grinding head provided so as to be linearly movable in the left-right direction The cylindrical grindstone is directed toward the outer peripheral surface of the cylindrical grindstone toward the clamp mechanism of the corner arc finishing grinding stage (s ₄ ) of the workpiece of the index type rotary table. The grinding head, which is rotatably supported on the grinding wheel shaft, can be moved up and down. Grinding head linearly movable in the lateral direction and,
The pair of polishing heads that support the polishing brush rotatably on the polishing shaft facing the clamping mechanism of the both-side flat finishing polishing stage (s ₅ ) of the workpiece of the index type rotary table can be moved up and down in the vertical direction and linearly moved in the horizontal direction. A prismatic silicon ingot chamfering apparatus characterized by comprising a polishing head provided in a possible manner. 4 Slice the periphery, clamp the prismatic silicon ingot (w) with the four arc corners left in the upright direction, and chamfer the prismatic silicon ingot through the following steps A) to D) A method of chamfering a prismatic silicon ingot characterized by the above.
A) Using a cup wheel type grindstone, chamfer the corners of the four arcs by rough grinding.
B) Chamfering the four side surfaces by grinding using a cup wheel type grindstone.
C) Using the outer peripheral surface of a cylindrical grindstone, chamfering is performed on the corners of the roughly ground four arcs by finish grinding.
D) Using a polishing brush, chamfering is performed by finishing and polishing the ground four side surfaces. A method for chamfering a prismatic silicon ingot, wherein the chamfering processing of the prismatic silicon ingot is performed using the chamfering apparatus according to claim 1 through the following steps 1) to 28).
1) The center axis of the headstock at the loading / unloading stage (s ₁ ) position on the index type rotary table is rotated for centering. Next, the prismatic silicon ingot (w) is placed on the center bearing base of the headstock so that the longitudinal direction thereof is the vertical direction, and then the center bearing base of the tailstock is lowered and the prismatic silicon ingot is lowered. Clamp both upper and lower ends.
2) The index type rotary table is rotated 72 degrees, and the prismatic silicon ingot (w) fixed to the clamp mechanism is moved to a position on the corner arc rough grinding stage (s ₂ ) on the index type rotary table. .
3) The center axis of the prismatic silicon ingot is centered by rotating the center shaft of the headstock.
4) The center axis of the headstock is rotated at a rotational speed of 10 to 300 rpm to rotate the prismatic silicon ingot (w) around its axis, while the cup wheel type grindstone supported by the grindstone axis of the grinding head is Move the cup wheel type grindstone to the left while rotating the grindstone shaft around its axis, and move the cup wheel type grindstone to the corner of the prismatic silicon ingot (w) Incision is started by contacting the part.
5) Relative movement of the prismatic silicon ingot (w) on the corner circular arc rough grinding stage (s ₂ ) and leftward movement for the up-and-down movement and cutting of the rotating cup wheel grindstone R chamfering rough grinding is performed by scraping the four corners of the prismatic silicon ingot (w) by a typical movement. In this R chamfering rough grinding process, the grinding fluid is supplied toward the machining work point where the prismatic silicon ingot (w) and the cutting edge of the cup wheel grindstone come into contact with each other.
6) After finishing the desired amount of R chamfering rough grinding of the four corners of the prismatic silicon ingot (w), the cup wheel type grindstone is moved backward to the right to move away from the prismatic silicon ingot (w). Stop the rotation of the grinding wheel, raise and lower the cup wheel grinding wheel, and stop at the grinding start standby position. Meanwhile, the rotation of the center shaft of the headstock is stopped.
7) The index type rotary table is rotated 72 degrees, and the prismatic silicon ingot (w) fixed to the clamp mechanism is moved to a position on the both side surface grinding stage (s ₃ ) of the workpiece on the index type rotary table. Let
8) After rotating the center axis of the headstock to center the prismatic silicon ingot, the center axis rotation of the headstock is stopped.
9) A pair of grindstone shafts supporting the cup wheel type grindstone with respect to the prismatic silicon ingot (w) on both side surface grinding stages (s ₃ ) on the workpiece are lifted and stopped at the grinding start standby position, and then the cup A pair of grinding wheel shafts of the wheel type grinding wheel are synchronously rotated.
10) The cup wheel type grindstone supported by the pair of grindstone shafts is synchronously moved to the left or right and brought into contact with both side surfaces of the prismatic silicon ingot (w) to start cutting with the cutting edge of the cup wheel type grindstone. In addition, while performing the upward and downward movement of the pair of grinding wheel shafts, the cutting edge of the cup wheel type grinding wheel is rubbed against the side plane of the prismatic silicon ingot (w), and the cutting is repeated. Perform chamfering. During this side surface flattening processing step, the grinding fluid is supplied toward the processing work point where the prismatic silicon ingot (w) and the cutting edge of the cup wheel grindstone come into contact.
11) After finishing a desired amount of chamfering on both sides of the prismatic silicon ingot (w), the pair of cup wheel-type grindstones are retracted to the right or left to move away from the prismatic silicon ingot (w). Then, the rotation of the grindstone shaft of the pair of cup wheel type grindstones is stopped, the diamond cup wheel type grindstone is raised and lowered, and stopped at the grinding start standby position. In the meantime, the center shaft of the headstock is turned 90 degrees to center the prismatic silicon ingot (w).
12) The cup wheel type grindstone supported by the pair of grindstone shafts is synchronously moved to the left or right and brought into contact with both side surfaces of the prismatic silicon ingot (w) to start cutting with the cutting edge of the cup wheel type grindstone. In addition, while performing the upward or downward movement of the pair of grinding wheel shafts, repeated cutting and rubbing the cutting edge of the cup wheel type grinding wheel on the side plane of the prismatic silicon ingot (w) to obtain a desired amount of chamfering Processing. During this side surface flattening processing step, the grinding fluid is supplied toward the processing work point where the prismatic silicon ingot (w) and the cutting edge of the cup wheel grindstone come into contact.
13) After finishing a desired amount of chamfering on both sides of the prismatic silicon ingot (w), the pair of cup wheel type grindstones are retracted to the right or left to move away from the prismatic silicon ingot (w). Then, the rotation of the grindstone shaft of the cup wheel type grindstone is stopped, and the grindstone shaft of the cup wheel type grindstone is moved up and down and stopped at the grinding start standby position.
14) The index type rotary table is rotated 72 degrees, and the prismatic silicon ingot (w) fixed to the clamp mechanism is moved to the corner arc finishing grinding stage (s ₄ ) position on the index type rotary table.
15) After rotating the center axis of the headstock and centering the prismatic silicon ingot, the center axis rotation of the headstock is stopped.
16) Cylinder supported by the grinding wheel shaft of the grinding head provided on the left side of the prismatic silicon ingot (w) fixed to the clamp mechanism of the corner arc finishing grinding stage (s ₄ ) of the index type rotary table. The shape grindstone is moved upward or downward and stopped at the grinding start standby position.
17) The prismatic silicon ingot (w) whose upper and lower ends are fixed by the clamp mechanism is rotated around the center axis of the headstock, and the prismatic silicon ingot (w) is rotated around its axis. On the other hand, the cylindrical grindstone supported by the grindstone shaft of the grinding head is raised and lowered to the grinding start standby position, and then the cylindrical grindstone is moved to the right while rotating the grindstone shaft about its axis to form a cylindrical shape. Cutting is started by bringing the outer peripheral surface of the grindstone into line contact with the corner portion of the prismatic silicon ingot (w).
18) The cylindrical grindstone is moved up and down and cut in the left direction, and the outer peripheral surface of the cylindrical grindstone is rubbed against the corner portion of the prismatic silicon ingot (w) for cutting. Repeat the work to perform the desired amount of R chamfer finish grinding. During the four-corner R chamfering finish grinding of this prismatic silicon ingot (w), the grinding fluid is supplied toward the machining work point at which the corner of the prismatic silicon ingot (w) contacts the outer peripheral surface of the cylindrical grindstone. .
19) After finishing a desired amount of R chamfering finish grinding at the four corners of the prismatic silicon ingot (w), the cylindrical grindstone is retracted to the left to move away from the prismatic silicon ingot (w), and then the cylindrical grindstone The rotation of the grindstone shaft is stopped, the cylindrical grindstone is raised and lowered and stopped at the grinding start standby position. Meanwhile, the rotation of the center shaft of the headstock is stopped.
20) The index type rotary table is rotated 72 degrees, and the prismatic silicon ingot (w) fixed to the clamp mechanism is moved to the both-side planar finishing polishing stage (s ₅ ) position on the index type rotary table.
21) After rotating the center axis of the headstock to center the prismatic silicon ingot, the center axis rotation of the headstock is stopped.
22) The polishing shaft bearing the pair of polishing brushes on the square columnar silicon ingot (w) on the both-side planar finishing polishing stage (s ₅ ) of the workpiece is lifted and stopped at the grinding start standby position, The polishing shaft of the polishing brush is rotated synchronously.
23) The polishing brush supported by the pair of polishing shafts is synchronously moved to the left or right and brought into contact with both side surfaces of the prismatic silicon ingot (w) to start cutting with the brush bristles of the polishing brush, While moving up and down the pair of polishing shafts in the upward or downward direction, a desired amount of chamfering is performed by repeatedly cutting the brush bristles of the polishing brush against the side plane of the prismatic silicon ingot (w). In the side surface finish chamfering process, the polishing liquid is supplied toward a processing work point where the prismatic silicon ingot (w) and the polishing brush come into contact with each other.
24) After finishing the desired amount of chamfering on both sides of the prismatic silicon ingot (w), move the pair of polishing brushes back to the right or left to move away from the prismatic silicon ingot (w), The rotation of the polishing shaft of the pair of polishing brushes is stopped, the polishing brush is moved up and down, and stopped at the polishing start standby position. In the meantime, the center shaft of the headstock is turned 90 degrees to center the prismatic silicon ingot (w).
25) The pair of polishing brushes supported by the pair of polishing shafts are moved to the left or right in a synchronized manner so as to come into contact with both side surfaces of the prismatic silicon ingot (w) to start cutting with the brush bristles of the polishing brush. At the same time, while moving up and down the pair of polishing shafts in the upward or downward direction, repeated scoring of the brush bristles of the polishing brush against the side plane of the prismatic silicon ingot (w) is performed to perform a desired amount of chamfering. Do. In the side surface finish chamfering process, the polishing liquid is supplied toward a processing work point where the prismatic silicon ingot (w) and the bristles of the polishing brush come into contact with each other.
26) After finishing a desired amount of chamfering on both sides of the prismatic silicon ingot (w), move the pair of polishing brushes back to the right or left to move away from the prismatic silicon ingot (w), The polishing shaft of the polishing brush is moved up and down and stopped at the polishing start standby position.
27) The index type rotary table is rotated 72 degrees or 288 degrees in the reverse direction, and the prismatic silicon ingot (w) fixed to the clamp mechanism is loaded / unloaded on the index type rotary table (s ₁ ) Move to position.
28) The center shaft of the tailstock at the loading / unloading stage (s ₁ ) position is moved upward, and the cradle provided at the lower end of the center shaft is moved away from the upper end surface of the prismatic silicon ingot (w). Next, the chamfered prismatic silicon ingot (w) is removed from the headstock.

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