JP5527987B2 - Wire saw device and substrate manufacturing method - Google Patents

Description

  The present invention relates to a wire saw device and a method of manufacturing a substrate using the wire saw device.

  Conventionally, when manufacturing a semiconductor substrate including a solar cell element, etc., an ingot is cut into a predetermined size into a block shape, and after the block is bonded to a slice base with an adhesive, a wire saw device or the like is used. The substrate was manufactured by cutting into a plurality of sheets.

  The wire of the wire saw device is guided from a supply reel to a main roller by a guide roller and wound around the main roller to form a wire row. Further, the wire extending from the main roller is guided to the take-up reel by the guide roller, and is taken up by the take-up reel.

  As a slicing method in a wire saw, there is a method (fixed abrasive grain type) of cutting with an abrasive fixed wire in which abrasive particles are fixed to the wire from the beginning. For example, Patent Document 1 discloses that the relationship between the average diameter D of the abrasive grain fixing wire and the interval P around which the abrasive grain fixing wire is wound around the reel satisfies D <P <2D.

JP 2005-186202 A

  However, in the conventional wire saw device described above, there is a problem that when the abrasive fixed wires are supplied or taken up from the supply reel and the take-up reel, the abrasive fixed wires are damaged by rubbing the abrasive fixed wires. Even in the structure described in Patent Document 1, wire breakage that occurs during slicing cannot be sufficiently reduced. When a substrate is manufactured using such a wire saw device, there is a problem that it is difficult to manufacture the substrate with high accuracy.

  The present invention has been made in view of the above-described problems, and has an object to provide a wire saw device in which damage to an abrasive fixed wire is reduced, and a substrate manufacturing method using the wire saw device. To do.

A wire saw device according to an embodiment of the present invention includes abrasive grains fixed to a surface, includes a wire having an average diameter D, an outer peripheral surface having one end and the other end, and the wire is the one end and the other. A supply reel wound in multiple layers on the outer peripheral surface while reciprocating between ends, a plurality of main rollers for running the wire extending from the supply reel, and a winding for winding the wire extending from the plurality of main rollers The wire is wound from one end of the supply reel to the other end at intervals of greater than 2.3D and less than 4D for each layer, and from the other end of the supply reel to the one end. The wire is laminated between the two already wound wires and has a portion wound between the already wound wires. It is characterized by further having a portion wound up.

The manufacturing method of the board | substrate which concerns on one Embodiment of this invention contains the outer peripheral surface which contains the abrasive grain fixed to the surface, and has the wire of the average diameter D, the supply reel which sends out the said wire, and one end and the other end. A step of preparing a take-up reel and an ingot; a step of feeding out the wire from the supply reel; and the wire being reciprocated between the supply reel and the take-up reel while the wire is moved to the take-up reel. comprising the the steps of the one end and the back and forth between the other end wrapped multilayer on said outer peripheral surface, and a step of cutting the ingot by the wire between the wire take-up reel and the supply reel, in the step of winding said wire on said take-up reel, for each layer, the follower at one end interval of less than greater than 2. 3D 4D toward the other end from the take-up reel Winding yer, said from the other end of the take-up reel toward said one end, wound rather with between the wires of the wire has already been wound, across between the previously wound two of said wires, The wire is wound so as to be laminated.

  The wire saw apparatus which concerns on one Embodiment of this invention can reduce damage, such as a disconnection of an abrasive grain fixed wire, by the structure mentioned above.

  The substrate manufacturing method according to an embodiment of the present invention can manufacture a highly accurate substrate by the above-described steps.

It is the schematic which shows one Embodiment of the wire saw apparatus of this invention. It is sectional drawing which shows one form of the abrasive grain fixed wire wound around the reel in the wire saw apparatus of this invention. It is sectional drawing which shows the other form of the abrasive grain fixed wire wound by the reel in the wire saw apparatus of this invention.

  The wire saw device of the present embodiment includes abrasive grains fixed to the surface, includes a wire 3 having an average diameter D, an outer peripheral surface having one end and the other end, and the wire 3 is between one end and the other end. A supply reel 7 wound in multiple layers on the outer peripheral surface while reciprocating, a plurality of main rollers 5 for running the wires 3 extending from the supply reel 7, and a take-up reel 8 for winding the wires 3 extending from the plurality of main rollers 5. . When the average diameter of the wire 3 including the abrasive grains fixed on the surface is D and the interval P1 of the wire 3 wound from one end of the supply reel 7 toward the other end, P1 and D are 2.3D <P1. The wire 3 that satisfies the <4D relationship and is wound from the other end toward the one end has a portion that gets over the already wound wire 3 and a portion that is wound between the wires 3. Here, the average diameter D of the wire 3 is the average value obtained by measuring the diameter including the abrasive grains from three directions at any 10 locations of the wire 3. The wire saw apparatus of this embodiment manufactures a board | substrate by pressing and cut | disconnecting a cutting | disconnection object (block 1) to the wire 3 which travels between the some main rollers 5. FIG.

  The block 1 is formed by cutting the end portion of the ingot. Such an ingot is made of, for example, single crystal silicon or polycrystalline silicon. More specifically, when a single crystal silicon ingot is used, the single crystal silicon ingot has a cylindrical shape. The polycrystalline silicon ingot is generally a substantially rectangular parallelepiped and has a size that allows a plurality of silicon blocks to be taken out. The silicon block has a rectangular cross section (including a square), for example, 156 × 156. A 300 mm rectangular parallelepiped is formed.

  The block 1 is bonded to a slice base 2 made of a material such as a carbon material, glass, resin or the like by an adhesive or the like. The adhesive is made of an adhesive such as a thermosetting two-component epoxy type, an acrylic type, a reacrate type, or a wax, and the temperature is raised so that the substrate 1a can be easily separated from the slice base 2 after slicing. Thus, an adhesive whose adhesive strength is reduced is used. One or more blocks 1 bonded to the slice base 2 are arranged in the apparatus by the work holder 10.

  The wire 3 is supplied from the supply reel 7 and taken up on the take-up reel 8. The wire 3 is wound around a plurality of main rollers 5 between the supply reel 7 and the take-up reel 8 and is stretched between the main rollers 5. The wire 3 is made of, for example, a piano wire whose main component is iron or an iron alloy, and has a wire diameter of 80 μm to 180 μm, more preferably 120 μm or less. In the present embodiment, the wire 3 is an abrasive fixed wire in which abrasive grains made of diamond or silicon carbide are fixed around the wire by plating with nickel, copper, or chromium. The average grain size of the abrasive grains is preferably 5 μm or more and 30 μm or less, and D is 90 μm or more and 240 μm or less. Further, the concentration degree of the wire 3 is set to 2100 to 3100. The “concentration” here is the number of abrasive grains adhering per 1 m of wire. The degree of concentration in the present embodiment is a value obtained by converting an average value obtained by measuring the number of abrasive grains fixed to a wire having a length of 1.2 mm at every 3.3 cm of the wire at a total of 30 locations per 1 m.

  The coolant liquid is supplied to the wire 3 from the plurality of openings of the supply nozzle 4. The coolant liquid is made of a water-soluble solvent such as glycol. The supply flow rate of the coolant liquid supplied to the supply nozzle 4 is appropriately set according to the size and number of blocks. Further, the coolant liquid may be circulated and used, and the abrasive grains and chips contained in the coolant liquid are removed at that time.

  The main roller 5 includes a first main roller 5a and a second main roller 5b disposed below the block 1, and is made of, for example, a resin such as ester-based, ether-based, urea-based urethane rubber, or neurite, The diameter is about 150 to 500 mm and the length is about 200 to 1000 mm. A large number of grooves for arranging the wires 3 supplied from the supply reel 7 at predetermined intervals are provided on the surface of the main roller 5. The thickness of the substrate is determined by the relationship between the groove interval and the diameter of the wire 3.

  A dip tank 6 is provided below the wire 3 for the purpose of collecting block chips and coolant generated during cutting.

  The supply reel 7 and the take-up reel 8 have an abrasive grain fixing wire 3 wound around a bobbin-shaped surface made of steel or the like. The wire saw device also includes a motor for rotating the supply reel 7 and the take-up reel 8 at a predetermined speed, and a traverser for guiding the wire 3 to wind it at a predetermined position.

  The plurality of guide rollers 9 have a role of guiding the wire-3 from the supply reel 7 to the main roller 5 and from the main roller 5 to the take-up reel 8. Each guide roller 9 has a groove in which the wire 3 travels. Such a guide roller 9 is made of, for example, an ester-based or ether-based / urea-based urethane rubber, and in particular, by using an ether-based urethane rubber, the guide roller 9 has a guide roller 9 having a similar hardness than the ester-based one. Wear can be reduced.

  Further, the wire saw device includes means for adjusting the tension of the wire 3 wound around the supply reel 7 and the take-up reel 8 and a sensor for detecting the tension applied to the wire 3.

  The wire 3 is wound from one end of the supply reel 7 toward the other end so as to satisfy the relationship 2.3D <P1 <4D. In addition, as shown in FIG. 2, the wire 3 a wound from one end to the other end and the wire 3 b wound from the other end to the one end are alternately arranged on the outer surface of the supply reel 7. It is made into a multilayer. With such a configuration, damage to the wire 3 when the block 1 is cut can be reduced. The wire 3 is arranged so as to be substantially perpendicular (90 ° ± 5 °) to the central axis of the supply reel, and is wound around the reel.

  Below, the slicing method using a wire saw apparatus is demonstrated. The wire 3 is supplied from the supply reel 7 and is guided to the main roller 5 by the guide roller 9. The wire 3 is wound around the main roller 5 and arranged at a predetermined interval. By rotating the main roller 5 at a predetermined rotational speed, the wire 3 can travel in the longitudinal direction of the wire 3. The wire 3 traveling at high speed cuts the block 1 and is wound around the take-up reel 8. Further, the wire 3 is reciprocated by changing the rotation direction of the main roller 15. At this time, the length for supplying the wire 3 from the supply reel 7 is longer than the length for supplying the wire 3 from the take-up reel 8, and the new line is supplied to the main roller 5.

  The block 1 is cut by lowering the block 1 and relatively pressing the block 1 against the wire 3 while supplying the coolant liquid toward the wire 3 running at high speed. The block 1 is divided into a plurality of substrates 1a having a thickness of 200 μm or less, for example. At this time, the tension of the wire 3, the speed at which the wire 3 travels (travel speed), and the speed at which the block is lowered (feed speed) are appropriately controlled. For example, the maximum traveling speed of the wire 13 is set to 500 m / min or more and 1000 m / min or less, and the maximum feed speed is set to 350 μm / min or more and 1100 μm / min or less.

  At the same time as slicing the block 1, the slice base 2 is also cut by about 2 to 5 mm, and the substrate 1 a is put into the next cleaning step while being bonded to the slice base 2.

  In the cleaning step, an alkaline liquid or a neutral liquid is used as a cleaning liquid, and water-soluble coolant and dirt adhering to the substrate 1a are cleaned, and then the detergent is washed away with water. Then, the surface of the substrate 1a is completely dried by hot air or air and peeled off from the slice base 2 to complete the substrate 1a.

  When the interval P2 between the wires 3 wound from one end of the take-up reel 8 toward the other end is set, the wire 3 satisfies the relationship 2.3D <P2 <4D in the step of winding the take-up reel 8. The winding reel 8 is wound from one end to the other end. Here, assuming that the wire 3 is counted once when the winding reel 8 is wound from one end to the other end of the take-up reel 8, the wire 3a wound first is wound to the other end, and then the second time. The wire 3b to be wound is wound from the other end of the take-up reel 8 toward one end between the already wound wires 3a. Further, the wire 3c wound around the third time is wound from one end of the take-up reel 8 toward the other end, and the wire wound around the fourth time is wound around from the other end of the take-up reel 8 toward one end. It is wound in multiple layers at intervals P2 while reciprocating between one end and the other end. Further, all the layers may be wound at the same interval P2, and the interval may be changed for each layer within a range satisfying the relationship of 2.3D <P <4D. The wire 3 is arranged so as to be substantially perpendicular (90 ° ± 5 °) to the central axis of the take-up reel 8 and is wound around the take-up reel 8. Further, after winding the wire 3 around the take-up reel 8, the rotation of the main roller 5 is reversed, and the wire 3 is supplied from one end of the supply reel 7 to the other end at an interval larger than 2.3D and less than 4D. By reciprocating the wire 3 by the step of winding around the reel and the step of winding the wire 3 between the wires 3 already wound around the supply reel 7 from the other end of the supply reel 7 toward one end, The wire 3 is also wound around the supply reel 7 under the same conditions as described above.

  In the wire saw device of this embodiment, the wire 3 is wound around the take-up reel 8 from one end to the other end at an interval P that satisfies the relationship 2.3D <P2, and between the wires 3 that have already been wound. Even when the wire 3 is wound from the other end to the other end, even if the wire 3 has a large variation in diameter, such as a variation in grain size of abrasive grains, a variation in the amount of abrasive grains adhering to the wire 3, etc. When the wire 3 is wound around the take-up reel 8, it is possible to reduce the friction between the wires.

  In addition, the presence of the wire 3 wound in the (n + 1) th time between the wires 3 wound in the nth time makes it easy to be fixed at the position where the wire 3 is wound, and the collapse of the wire 3 can be reduced. . Therefore, the possibility that the previously wound wire 3 is positioned on the newly wound wire 3 is reduced, and the wire 3 is hard to break.

  Further, by winding the wire 3 around the take-up reel 8 at the interval P2 that satisfies the relationship P2 <4D, the winding step of the take-up reel 8 around which the wire 3 is wound is small, and the take-up reel around which the wire 3 is wound. The surface of 8 has a certain regular irregular shape, and the collapse of the wire 3 can be reduced. Thereby, generation | occurrence | production of the disconnection of the wire 3 can be reduced.

  In addition, the wire 3 is wound around the supply reel 8 from one end to the other end at an interval P1 that satisfies the relationship 2.3D <P1 <4D, and further between the other ends of the wire 3 that has already been wound. By causing the wire 3 to be wound around, occurrence of disconnection of the wire 3 can be reduced.

  Further, the tension of the wire 3 wound around the supply reel 7 and the take-up reel 8 is set to 15N or more and 20N or less, so that loosening when winding the wire 3 and loosening after winding are reduced, and the reel by tightening the wire It is possible to suppress damage to the main body and reduce slice defects. In addition, the collapse of the wire 3 can be further reduced.

  Further, when the wire 3 is wound around the supply reel 7 or the take-up reel 8, the reel may be placed sideways and the wire may be wound while reciprocating in the horizontal direction, or the reel may be placed vertically. The wire may be wound while being reciprocated in the vertical direction. In particular, when the reel is placed in the vertical direction, the wire 3 is easily collapsed due to the influence of gravity, but problems such as the collapse can be reduced by the above-described winding method.

  In addition, this invention is not limited to the said embodiment, Many corrections and changes can be added within the scope of the present invention.

  For example, the slicing process may be performed as it is without cutting the ingot 1.

  Further, the wire 3 was wound from one end of the take-up reel 8 toward the other end (first time) and from the other end toward the one end (second time) so as to satisfy the relationship of 3D <P2 <4D. Thereafter, as shown in FIG. 3, the wire 3 c wound around the third time is between the first wire 3 a and the second wire 3 b already wound from one end to the other end of the take-up reel 8. It does not matter if it is wound around.

Example 1
Examples will be described below. First, an epoxy adhesive was applied to a slice base made of a glass plate, and a rectangular parallelepiped polycrystalline silicon block of 156 mm × 156 mm × 300 mm was placed on the slice base to cure the adhesive. A silicon block bonded to two slice bases is installed in a wire saw device, and both wires with diamond abrasive grains fixed by Ni plating (wire diameter = 130 μm, abrasive grain diameter = 15 μm, average diameter D = 160 μm) are both used. The block adhered to the slice base was sliced while running in the direction to produce a silicon substrate having an average thickness of 200 μm. At this time, the tension of the wire 3 wound around the supply reel 7 and the take-up reel 8 is 17.5 N, and the wire interval P2 in the take-up reel 8 is 0.2 μm, 0.36 μm, 0.37 μm,. The wire breakage rate was evaluated for 10 types of 4 μm, 0.5 μm, 0.6 μm, 0.64 μm, 0.65 μm, 0.8 μm, and 0.9 μm. The results are shown in Table 1.

  As shown in Table 1, no. From the result of 1-10, when the space | interval P which winds the wire 3 with which the abrasive grain fixed was wound to a supply reel and a take-up reel satisfy | fills the relationship of 2.3 <P / D <4 (No. 3-6) It was confirmed that the wire breakage rate was reduced to less than 1%.

(Example 2)
Next, the wire interval P2 of the take-up reel 8 is 0.4 μm, and the tension of the wire wound around the take-up reel 8 is 10N, 15N, 17.5N, 20N, and 25N. The defective rate of the slice was evaluated. Defect items include the presence or absence of slicing marks, the presence or absence of undulations, and the presence or absence of waviness. The defect rate is calculated.

  No. From the result of 11-15, it was confirmed that the tension | tensile_strength of the wire wound around the winding reel 8 satisfy | fills 15N or more and 20N or less (No. 12-14), and reduces a slice defect rate to less than 1%. .

1: Block 1a: Substrate 3: Wire 5: Main roller 7: Supply reel 8: Take-up reel

Claims (4)

A wire having an average diameter D, including abrasive grains affixed to the surface;
A supply reel including an outer peripheral surface having one end and the other end, wherein the wire is wound around the outer peripheral surface in multiple layers while reciprocating between the one end and the other end;
A plurality of main rollers for running the wire extending from the supply reel;
A take-up reel that winds up the wire extending from the plurality of main rollers,
The wire is wound from one end of the supply reel to the other end at intervals of greater than 2.3D and less than 4D for each layer, and already wound from the other end of the supply reel to the one end. Having a portion wound between said wire
The wire saw device further comprising a portion in which the wires are stacked and wound between the two already wound wires. Preparing a wire having an average diameter D, a supply reel for feeding the wire, a take-up reel including an outer peripheral surface having one end and the other end, and an ingot, including abrasive grains fixed to the surface;
Feeding the wire from the supply reel;
Reciprocating the wire between the one end and the other end of the take-up reel while reciprocating the wire between the supply reel and the take-up reel, and winding the multi-layer around the outer peripheral surface ;
Cutting the ingot with the wire between the supply reel and the wire take-up reel;
With
In the step of winding the wire around the take-up reel, for each layer, the wire is wound at an interval of more than 2.3D and less than 4D from one end to the other end of the take-up reel. towards the end on the one end, we wound rather with between the wires the wire was already been wound,
A method of manufacturing a substrate, wherein the wires are wound so as to be stacked between the two already wound wires. The substrate manufacturing method according to claim 2 , wherein a tension of the wire wound around the take-up reel is 15 N or more and 20 N or less. Said take-up reel placed vertically, method for manufacturing a substrate according to claim 2 or claim 3 wherein the back and forth motion in the vertical direction wire and wherein the winding on the take-up reel.

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