JP2006212958A - Band saw-type cutter and semiconductor ingot cutting method using the cutter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a band saw-type cutter which is good in surface roughness of a cut plane and can improve a cutting speed when a semiconductor ingot is cut and a method for cutting a semiconductor ingot using the cutter. <P>SOLUTION: In the band saw-type cutter 1, two or more blade parts for cutting the semiconductor ingot 6 are arranged on an endless belt 2, and the belt 2 and the ingot 6 are moved relatively while the belt 2 is driven to cut the ingot 6 in the width direction of the belt 2. The blade parts include a first blade part 3 arranged in the edge part of the belt 2 and a second blade part 4 the surface roughness of which is lower than that of the first blade part 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a band saw type cutting machine for cutting a semiconductor ingot such as gallium arsenide or silicon, and a cutting method using the same.

  Conventionally, there is a band saw type cutting machine using an endless belt as a cutting machine for removing an end of a semiconductor ingot such as gallium arsenide or silicon or cutting it into a desired size. FIG. 12 is a schematic view showing the structure of a conventional band saw type cutting machine, and FIG. 13 is an enlarged view of a conventional endless belt portion. 12 and 13, 11 is a band saw type cutting machine, 12 is an endless belt, 13 is a blade portion, 15 is a pulley, and 16 is a semiconductor ingot. The band saw type cutting machine 11 uses an endless belt 12 between two pulleys 15. This band saw type cutting machine 11 is formed of abrasive grains such as diamond and CBN (cubic boron nitride) on a base metal such as stainless steel or high-tensile steel, which is an endless belt 12, as shown in FIG. The blade part 13 made is mounted. Further, the band saw type cutting machine 11 has a metal band saw in which blade portions 13 formed by sintering abrasive grains together with a metal binder are fixed to the end portion of the endless belt 12 by brazing at predetermined intervals, or a predetermined position. There is an electrodeposition band saw in which abrasive grains are fixed by electrodeposition.

FIG. 14 shows a state in which the semiconductor ingot 16 is cut with the arrangement of the blade portions shown in FIG. In FIG. 14, 12 is an endless belt, 13 is a blade portion, and 16 is a semiconductor ingot. In a state where the endless belt 12 shown in FIG. 12 is tensioned by the two pulleys 15, the endless belt 12 is rotated in parallel by the rotational drive of the pulley 15, and is translated downward in advance. Is cut by pressing the endless belt 12 against the semiconductor ingot 16 placed underneath.
JP 2002-346833 A

  However, when the semiconductor ingot 16 is cut using the conventional band saw type cutting machine 11 as shown in FIG. 13, the semiconductor casting cut along both side surfaces of the blade portion 13 made of abrasive grains as shown in FIG. The both sides of the mass 16 come into contact. When cutting is performed in such a state that both side surfaces of the blade portion 13 are in contact with the semiconductor ingot 16, the endless belt 12 is formed at the bottom portion and the cut surface (side portion) which are the cutting surfaces of the blade portion 13 and the semiconductor ingot 16. There is a problem that the endless belt 12 is likely to be shaken or bent due to an increase in resistance between the blade portion 13 attached to the semiconductor ingot 16 and the semiconductor ingot 16 and the surface roughness of the cut surface is deteriorated. Although the deterioration of the surface roughness of the cut surface can be suppressed by slowing the cutting speed, the productivity is lowered.

  In order to process the semiconductor ingot 16 into a product such as a solar battery cell, the semiconductor ingot 16 is cut into a desired size and then sliced using a multi-wire saw or the like to form a flat semiconductor wafer from the semiconductor ingot 16. If the surface roughness of the cut semiconductor ingot 16 is poor, the semiconductor wafer is easily chipped, cracked or cracked during slicing. Further, even in a semiconductor wafer that has no problem in the slicing process, due to the surface roughness of the cut surface of the semiconductor ingot 16 in a cell forming process (wafer diffusion process, electrode formation process, etc.) that is a subsequent process. There was a problem that chipping, cracking, cracking, etc. occurred and the yield of the product was lowered.

  After the semiconductor ingot 16 is cut, the surface roughness can be smoothed by performing an etching process or polishing the cut surface. However, it is necessary to provide a separate processing facility, and the equipment cost and processing time are reduced. Therefore, the problem that productivity decreases is not solved.

  Patent Document 1 describes an electrodeposition band saw in which diamond abrasive grains are fixed by electrodeposition. FIG. 15 shows an example of the arrangement of the blade portions of the band saw type cutting machine disclosed in Patent Document 1. As shown in FIG. 15, the plurality of blade portions are mounted on the endless belt 22 while changing the height alternately. FIG. 16 shows a state in which the semiconductor ingot 26 is cut with the arrangement of the blade portions shown in FIG.

  FIG. 16A shows a state where the semiconductor ingot is cut by the blade portion 23b having a high blade edge. FIG. 16B shows a state in which the cutting surface is sharpened by the blade portion 23c having a low blade edge and a thicker thickness than the blade portion 23b.

  As described above, the portion cut by the thin blade portion 23b with a high blade edge has a low cutting surface roughness, but the semiconductor ingot 26 is cut by the thin blade portion 23b with a high blade edge and a small thickness. A portion having a poor surface roughness is scraped by the blade portion 23c having a thin blade edge and a thick side surface. And since the part B cut | disconnected by the blade part 23c with a low blade edge is few compared with the part A cut | disconnected by the blade part 23b with a high blade edge | tip, in the cutting | disconnection by the blade part 23c with a low blade edge | tip, a band saw's run-out and bending Occurrence can be suppressed.

  However, it cannot be said that the surface roughness of the cut surface of the semiconductor ingot 26 formed by using the above method can be improved. Thus, since the fall of the surface roughness of a cut surface cannot fully be suppressed, the fall of the yield in a subsequent slicing process or cell-forming process could not be suppressed.

  As a result of intensive studies on the above problems, the present inventors have found the following facts.

  When an electrodeposited band saw equipped with blade portions 23b and 23c having different blade edge heights and thicknesses as in Patent Document 1, as shown in FIG. 16, first, a semiconductor ingot is formed by a blade portion 23b having a high blade edge. 26 is cut off. At this time, the resistance that the semiconductor ingot 26 and the blade portion 23b having a long blade edge and a small thickness come into contact with each other occurs. This resistance is vibrated and transmitted through the endless belt 22 to the blade portion 23c having a short blade edge and a large thickness. As a result, the blade edge 23c having a short cutting edge and a thick width which should finish the cut surface of the semiconductor ingot 26 cannot suppress the surface roughness of the cut surface of the semiconductor ingot 26 due to vibration or bending of the endless belt 22. It was. On the contrary, it was found that when the cutting speed was increased, the vibration was transmitted to the entire band saw type cutting machine 21 and the surface roughness of the semiconductor ingot 26 cut by the blade portion 23c was further deteriorated.

  The present invention has been made in view of such knowledge, and when cutting a semiconductor ingot (ingot) such as gallium arsenide or silicon, the surface roughness of the cut surface is good and the cutting speed can be improved. An object of the present invention is to provide a band saw type cutting machine and a cutting method using the same.

  In the band saw type cutting machine according to claim 1 of the present invention, a plurality of blade portions for cutting a semiconductor ingot are arranged on an endless belt, and the endless belt, the semiconductor ingot, Is a band saw type cutting machine that cuts the semiconductor ingot in the width direction of the endless belt, wherein the plurality of blade portions are arranged at the edge of the endless belt. A blade portion and a second blade portion having a surface roughness smaller than that of the first blade portion are included.

  A band saw type cutting machine according to a second aspect of the present invention is the band saw type cutting machine according to the first aspect, wherein the second blade portion is formed on an outer surface of the endless belt excluding the front end portion in the cutting direction. It was arranged.

  A band saw type cutting machine according to a third aspect of the present invention is the band saw type cutting machine according to the first or second aspect, wherein the first blade portion is formed on the endless belt. It arrange | positions in the position which contacts the said semiconductor ingot before a blade part.

  A band saw type cutting machine according to a fourth aspect of the present invention is the band saw type cutting machine according to any one of the first to third aspects, wherein the second blade portion has a thickness of the endless belt. It protruded outside the first blade portion in the direction.

  A band saw type cutting machine according to a fifth aspect of the present invention is the band saw type cutting machine according to any one of the first to fourth aspects, wherein the endless belt has the first end on both edges thereof. While having one blade part, it has a mechanism for moving the endless belt with respect to the cutting direction of the semiconductor ingot.

  A band saw type cutting machine according to claim 6 of the present invention is the band saw type cutting machine according to any one of claims 1 to 5, wherein the first blade portion is at least on an outer surface thereof. The first abrasive grains are included, and the second blade portion includes at least the second abrasive grains having a particle diameter smaller than that of the first abrasive grains on the outer surface thereof.

  A band saw type cutting machine according to a seventh aspect of the present invention is the band saw type cutting machine according to the sixth aspect, wherein the first abrasive grains have a particle size of # 40 or more and # 200 or less, and the second abrasive. The grain size was set to 1.3 times or more of the grain size of the first abrasive grain.

  A band saw type cutting machine according to an eighth aspect of the present invention is the band saw type cutting machine according to the sixth aspect, wherein the first abrasive has a grain size of # 80 to # 120, and the second abrasive The grain size was set to # 120 or more and # 1000 or less.

  A method for cutting a semiconductor ingot according to claim 9 of the present invention is a method for cutting a semiconductor ingot using the band saw type cutting machine according to any one of claims 1 to 8, wherein A first step of cutting the semiconductor ingot with the first blade portion and a second step of finishing the cut surface of the semiconductor ingot with the second blade portion are included.

  In the band saw type cutting machine according to the present invention, a plurality of blade portions for cutting a semiconductor ingot are arranged on an endless belt, and the endless belt and the semiconductor ingot are relatively moved while rotating the endless belt. It is a band saw type cutting machine that moves and cuts the semiconductor ingot in the width direction of the endless belt, wherein the plurality of blade portions are a first blade portion disposed at an edge of the endless belt; And a second blade portion having a surface roughness smaller than that of the first blade portion.

  By cutting the semiconductor ingot using such a band saw type cutting machine, the first blade portion is arranged at the edge of the endless belt, and the first blade portion has a rough surface, so the cutting ability is high. Efficiently cut semiconductor ingots. And since the second blade portion whose surface is not rough compared to the first blade portion is in contact with the cut surface of the semiconductor ingot, the surface roughness of the cut surface is small, and a good cut surface can be obtained. it can.

  In a semiconductor ingot cut by such a band saw type cutting machine, generation of chips, cracks, cracks, and the like is suppressed in the slicing step and cell forming step, and the problem of a decrease in product yield can be suppressed.

  Furthermore, in the semiconductor ingot cutting method using these band saw type cutting machines, in the first step, the semiconductor ingot is efficiently cut by the first blade portion having high cutting ability, and in the second step, the second blade is cut. By finishing the cut surface of the semiconductor ingot at the part, a method for obtaining a semiconductor ingot having a good surface roughness of the cut surface can be obtained.

  Hereinafter, a band saw type cutting machine of the present invention will be described in detail with reference to the accompanying drawings. Here, 1st embodiment of this invention shows the shape which has a 1st blade part in one edge part of an endless belt, and in 2nd embodiment, it has a 1st blade part in the edge part of both endless belts. Show shape.

  First, the band saw type cutting machine 1 which concerns on 1st embodiment of this invention is demonstrated. FIG. 1 is a diagram showing an outline of a first embodiment of a band saw type cutting machine according to the present invention, wherein 1 is a band saw type cutting machine, 2 is an endless belt, 3 is a first blade portion, and 4 is a second blade. And 5 are pulleys and 6 is a semiconductor ingot.

  The band saw type cutting machine 1 of the present invention uses an endless belt 2 between two pulleys 5 as shown in FIG. Further, the semiconductor ingot 6 can be cut by relatively moving the endless belt 2 having the first blade portion 3 and the semiconductor ingot 6. Here, relative movement means that the endless belt 2 may be fixed and the semiconductor ingot 6 may be brought closer to the endless belt 2, or the semiconductor ingot 6 may be fixed and the endless belt 2 may be brought closer. Means.

  The endless belt 2 has a first blade portion 3 and a second blade portion 4 arranged on a base metal such as stainless steel or high-tensile steel. The first blade portion 3 is characterized in that the surface is rougher than the second blade portion. By arranging the blade portions having different surface roughness in this way, the cutting ability is improved by the first blade portion 3 disposed at the edge portion of the endless belt 2, and the second blade portion 4 is more efficient. It is possible to finish the cut surface.

  In addition, after the first blade portion 3 is in contact with the semiconductor ingot 6, the second blade portion 4 having a surface roughness smaller than that of the first blade portion 3 is in contact with the semiconductor ingot 6. The semiconductor ingot after cutting can be made into a better cut surface.

  The first blade portion 3 and the second blade portion 4 are made of, for example, diamond or cemented carbide tools, or abrasive grains made of diamond, CBN (cubic boron nitride), or the like. There is something.

  Further, the description will be made mainly by focusing on the two types of blade portions 3 and 4, but even if three or more types of blade portions are provided on the endless belt, the effects of the present invention can be sufficiently obtained.

  The terms particle size and particle size appear in the text. Based on JIS R6001, the particle size and particle size of the abrasive will be explained based on specific numerical values. The grain size of the first abrasive grain according to the present invention corresponds to F in JIS R6001, but is treated as # here for convenience.

  When comparing the grain size of the first abrasive grain and the second abrasive grain, for example, if # 100, the average grain size is 149 μm, and if # 1000, the average grain size is 15 μm. Yes.

  In a state where the endless belt 2 is tensioned by the pulling of the two pulleys 5, the endless belt 2 is driven to rotate around the endless belt 2 by the rotational drive of the pulley 5, and is moved in parallel in the width direction of the endless belt 2. The semiconductor ingot 6 is cut by pressing the first blade portion 3 and the second blade portion 4 disposed on the endless belt against the semiconductor ingot 6 placed below the semiconductor ingot 6.

  Since the cut surface of the semiconductor ingot 6 thus cut has a very small surface roughness and is good, in the subsequent process after cutting, in the slicing process and the cell forming process for forming a semiconductor wafer, chipping, cracking and Generation | occurrence | production of a crack etc. is suppressed and the problem that the yield of a product falls can be suppressed.

  Hereinafter, the order of the claims of the present invention will be described with respect to the shapes and positions of the first blade portion 3 and the second blade portion 4 disposed on the endless belt 2, which is a characteristic part of the first embodiment of the present invention. Details will be described later.

  First, FIG. 2A and FIG. 2B show a first example of the arrangement of the blade portions 3 and 4 according to the first embodiment of the present invention.

  2 (a) and 2 (b), 2 is an endless belt, 3 is a first blade portion, and 4 is a second blade portion. The first blade portion 3 and the second blade portion 4 according to the present invention are alternately arranged on the edge portion of the endless belt 2, and while the endless belt 2 is driven to rotate, it is translated in the width direction of the endless belt 2, The semiconductor ingot 6 is cut by pressing the endless belt 2 against the semiconductor ingot 6 previously placed below the band saw type cutting machine 1.

  FIG. 3 shows a state where the semiconductor ingot 6 is cut by the arrangement of the first blade portion 3 and the second blade portion 4 shown in FIG. 3A and 3B, 2 is an endless belt, 3 is a first blade portion, 4 is a second blade portion, and 6 is a semiconductor ingot. As shown in FIG. 3A, the semiconductor ingot 6 is cut by the first blade portion 3. Further, as shown in FIG. 3B, the cut surface of the semiconductor ingot 6 is finished by the second blade portion 4.

  As described above, the first blade portion 3 has a rougher surface than the second blade portion 4 and has a high cutting ability, so that the semiconductor ingot 6 can be efficiently cut, and the surface of the first blade portion 3 is higher than that of the first blade portion 3. Since the surface of the cut surface of the semiconductor ingot 6 is shaved by the second blade portion 4 having a small roughness, the surface of the cut surface is small and good depending on the surface roughness of the second blade portion 4. Obtainable.

  Further, the second blade portion 4 having a surface roughness smaller than that of the first blade portion 3 is in contact with the semiconductor ingot 6, so that the endless belt 2 receives vibration and the blade portion contacts the cut surface. Even so, since the surface roughness is small, the cut surface of the semiconductor ingot 6 can be obtained with a small surface roughness of the cut surface of the semiconductor ingot 6.

  Here, if the surface roughness is small, the cutting ability is inferior to that of the abrasive grains having a large particle size, and therefore it is necessary to slow down the cutting speed. In the present invention, the first blade 3 and the second blade By attaching the blade part 4 at the same time, even if the cutting speed is increased, the first blade part can have sufficient cutting ability, and the second blade part 4 has a good surface roughness of the cut surface. Therefore, it is not necessary to reduce the cutting speed as compared with the prior art. For this reason, a good semiconductor wafer can be produced without reducing productivity.

  Next, FIG. 4 shows a state where the semiconductor ingot 6 is cut by the arrangement of the first blade portion 3a and the second blade portion 4a shown in FIG. 2 (b). 4 (a) and 4 (b), 2 is an endless belt, 3a is a first blade portion shorter than 4a, 4a is a second blade portion longer than 3a, and 6 is a semiconductor ingot. is there. As shown to Fig.4 (a), the semiconductor ingot 6 is cut | disconnected by the 1st blade part 3a. And as shown in FIG.4 (b), a finishing process is given to the cut surface of the semiconductor ingot 6 cut | disconnected by the 1st blade part 3 with the 2nd blade part 4a whose blade edge is longer than a 1st blade part.

  Here, as is apparent from a comparison between FIGS. 4A and 4B, the second blade portion 4 is longer in the endless belt width direction than the first blade portion 3. Yes. That is, by aligning the blade edge positions of the first blade portion 3 and the second blade portion 4 to substantially the same position, the second blade portion 4 finally comes into contact with the cut surface of the semiconductor ingot 6. A material having a good surface roughness on the cut surface can be obtained. Further, even when the endless belt 2 receives vibration caused by the contact between the first blade portion 3 and the semiconductor ingot 6, the area where the second blade portion 4 and the semiconductor ingot 6 are in contact with each other is small. Since it is large, the influence of friction exerted on the cutting surface by the second blade portion 4 can be dispersed, and the surface roughness of the second blade portion 4 is smaller than that of the first blade portion 3, so that the endless belt 2 Even when subjected to vibration, the deterioration of the surface roughness can be minimized. As a result, the semiconductor ingot 6 having a good cut surface roughness can be obtained.

  Here, when only a blade portion having a small surface roughness is used, the cutting ability is inferior to that of a blade portion having a large surface roughness, so it is necessary to slow down the cutting speed. By simultaneously mounting the blade portion 3 and the second blade portion 4 having a surface roughness smaller than that of the first blade portion, it is possible to have sufficient cutting ability even if the cutting speed is increased. A cut surface with good surface roughness can be obtained in a short time. Since the portion cut by the second blade portion 4 may be cut to such an extent that the cut surface cut by the first blade portion 3 is cut, the thickness of each blade portion may be substantially the same. For this reason, a good semiconductor wafer can be produced without reducing productivity.

  Next, the 2nd example of arrangement | positioning of the blade part 3 which concerns on Fig.5 (a) and FIG.5 (b) which concerns on 1st embodiment of this invention is shown.

  5A and 5B, 2 is an endless belt, 3 is a first blade portion, and 4 is a second blade portion. The 1st blade part 3 which concerns on this invention was arrange | positioned at the cutting direction front-end | tip part of the semiconductor ingot of the endless belt 2. FIG. Further, the second blade portion 4 was disposed on the outer surface of the endless belt 2 excluding the front end portion in the cutting direction where the first blade portion 3 was disposed.

  In particular, in FIG. 5A, the second blade portion 4 is disposed on the outer surface of the endless belt 2 above the edge of the endless belt 2 where the first blade portion 3 is disposed. Moreover, about FIG.5 (b), the 2nd blade part 4 is arrange | positioned at the edge part of the endless belt 2 on the opposite side to the edge part of the endless belt in which the 1st blade part 3 is arrange | positioned. Moreover, the 2nd blade part 4 should just be arrange | positioned on the outer surface of the endless belt 2 without being restricted to this.

  FIGS. 6 (a) and 6 (b) show a state where the semiconductor ingot is cut with the arrangement of the blade portions shown in FIGS. 5 (a) and 5 (b). 6 (a) and 6 (b), 2 is an endless belt, 3 is a first blade portion, 4 is a second blade portion, and 6 is a semiconductor ingot.

  Thus, since the first blade 3 has a larger surface roughness and higher cutting ability than the second blade 4, the semiconductor ingot 6 is efficiently cut. In addition, the second blade portion 4 having a small surface roughness can provide a cutting surface with a good surface roughness. Furthermore, the thickness of the base metal that normally constitutes the endless belt is about 1 mm, and the impact when the endless belt is driven to circulate and the semiconductor ingot is cut is easily transmitted to the endless belt. By arranging the first blade portion 3 and the second blade portion 4 as shown in FIG. 5B, the second blade portion 4 according to the present invention is the first blade portion on the cut surface of the semiconductor ingot 6. 3 also plays a role of the support member 3, so that even when the cutting speed is increased, the vibration received when the semiconductor ingot 6 is cut can be reduced. Moreover, since the part which the 2nd blade part 4 cut | disconnects should just cut | disconnect to the extent which cuts the cut surface which the 1st blade part 3 cut | disconnected, the thickness of each blade part may be substantially the same.

  Therefore, in the semiconductor ingot cut by such a band saw type cutting machine, the occurrence of chipping, cracking, cracking, etc. is suppressed in the slicing process and cell forming process, and the problem of reduced product yield can be suppressed. it can.

  Further, FIGS. 7A and 7B show a third example in the arrangement of the blade portions according to the first embodiment of the present invention. In FIG. 7A, 2 is an endless belt, 3 is a first blade portion, and 4 is a second blade portion. In FIG. 7B, 3b is a first blade portion that is long in the endless belt width direction, and 4b is a second blade portion that is shorter than the first blade portion 3b in the endless belt width direction. is there. The 1st blade part 3 and 3b which concerns on this invention was arrange | positioned on the endless belt 2 in the position which contacts the semiconductor ingot 6 ahead of the 2nd blade part 4 and 4b.

  As described above, as a method of changing the first blade portion 3, 3 b according to the first embodiment of the present invention to a position in contact with the semiconductor ingot 6 before the second blade portion 4, 4 b, FIG. 7 (a), the length of the first blade portion 3 and the second blade portion 4 are made the same, and the edge of the endless belt 2 is processed, or as shown in FIG. 7 (b). In the case where the first blade portion and the second blade portion are formed from abrasive grains, it is conceivable to form two or more types of abrasive grains having different particle diameters by solidifying them with a binder or the like. In this way, the first blade portions 3, 3b can be brought into contact with the semiconductor ingot 6 before the second blade portions 4, 4b.

  Here, FIGS. 8A and 8B show a state in which the semiconductor ingot 6 is cut with the arrangement of the blade portions shown in FIGS. 7A and 7B.

  It is desirable that the first blade portions 3 and 3b are arranged at positions where the endless belt 2 contacts the semiconductor ingot 6 before the second blade portions 4 and 4b. As this reason, the semiconductor ingot 6 is more reliably cut | disconnected by the 1st blade part 3b. And it is because a finishing process can be given to the cut surface of the semiconductor ingot 6 cut | disconnected by the 1st blade part 3 and 3b with the 2nd blade part 4 and 4b.

  Thus, since the first blade portions 3 and 3b have a larger surface roughness than the second blade portions 4 and 4b and have a high cutting ability, the semiconductor ingot 6 is efficiently cut from the first blade portions. In addition, by cutting the surface of the cut surface with the second blade portion 4b having a small surface roughness, a good one having a small surface roughness of the cut surface can be obtained.

  In addition, after the first blade portions 3 and 3b are in contact with the semiconductor ingot 6, the second blade portions 4 and 4b having a smaller surface roughness than the first blade portions 3 and 3b are in contact with the semiconductor ingot. Therefore, since the deterioration of the surface roughness caused by the vibration of the endless belt 2 and the contact of the blade portion with the cut surface can be suppressed, a good semiconductor with a further reduced surface roughness of the cut surface An ingot can be obtained. Moreover, since the part which the 2nd blade part 4 cut | disconnects should just cut | disconnect to the extent which cuts the cut surface which the 1st blade part 3 cut | disconnected, the thickness of each blade part may be substantially the same.

  In the semiconductor ingot 6 cut by such a band saw type cutting machine, the occurrence of chipping, cracking, cracking or the like is suppressed in the slicing step or cell forming step, and the problem of a decrease in product yield can be suppressed. .

  9A and 9B show a fourth example of the arrangement of the blade portion 3 according to the first embodiment of the present invention, in which the thickness of the blade portion is changed and the semiconductor ingot is cut. Indicates.

  9 (a) and 9 (b), 2 is an endless belt, 3c is a first blade portion, and 4c is a second blade portion. The 2nd blade part 4c which concerns on this invention was made to protrude outside the 1st blade part 3c in the thickness direction of the endless belt 2. FIG.

  As a method of fixing the endless belt 2 by changing the thickness, metal bonds are preferable to electrodeposition when abrasive grains are used.

(1) In the case of a metal bond type Since the blade portion formed by sintering the abrasive grains together with the metal binder is fixed to the endless belt, the abrasive layer can be multilayered. Can be easily changed (2) Electrodeposited bond type The blade portion made of abrasive grains is energized at once, and immersed in a nickel plating bath to fix the abrasive grains to the endless belt. When the thickness of the blade is changed with an electrodeposition band saw in which the grains are fixed by electrodeposition, the plating layer joins the abrasive grains and the wheel base metal to hold the abrasive grains. In this method, the abrasive layer is usually composed of a single layer. At this time, variations in the protruding amount of the abrasive grains occur, and the abrasive grain heights of the processed surfaces are not uniform, so that the cut surface of the semiconductor ingot is deteriorated. Therefore, the cut surface cut by this electrodeposition band saw cannot obtain high processing accuracy.

  For example, as shown in FIG. 15, blade portions 23b and 23c having different blade heights are alternately arranged at a constant interval on the endless belt 2, and the cutting width of the blade portion 23c having a low blade edge is set to a blade portion having a high blade edge. If it is thicker than 23b, it is necessary to make the grain size of the abrasive grains larger in the blade portion 23c having a shorter blade edge than in the blade portion 23b having a higher blade edge.

  However, in the case of the electrodeposition bond type in the present invention, when the thickness is changed, the thickness of the endless belt itself is partially changed, or a base layer or the like is provided, so that the thickness of the first blade portion and the second blade portion are increased. It is possible to change the thickness of the blade portion, but the metal bond type is preferable in the present invention because the blade portion can be easily formed by abrasive grains and a metal binder, so that the thickness is easily changed.

  Furthermore, the thickness of the cemented carbide tool may be changed as a case where the blade portion having a different thickness is formed from something other than abrasive grains.

  The semiconductor ingot 6 can be cut using the first blade portion 3c and the second blade portion 4c having different thicknesses produced as described above.

  As shown in FIG. 9A, the semiconductor ingot 6 is cut by the first blade portion 3c, and the second blade portion 4c has a wider range than the cutting range cut by the first blade portion 3c. By cutting with the blade part 4c, it becomes possible to perform more effective finishing with respect to the cut surface of the semiconductor ingot 6. FIG.

  As described above, when abrasive grains are used, the cut surface of the semiconductor ingot 6 can have a better surface roughness by changing the shapes of the first blade portion 3 and the second blade portion 4. . As described above, since the first blade 3c formed from the first abrasive grains has a higher cutting ability than the second blade 4c, the semiconductor ingot 6 is efficiently cut, and the first A semiconductor ingot 6 having a particularly good surface roughness on the cut surface can be obtained by the second blade portion 4c that protrudes outward in the thickness direction of the endless belt 2 from the blade portion 3c.

  Thus, after the 1st blade part 3c contact | connects the semiconductor ingot 6, the 2nd blade part 4c whose surface roughness is smaller than the 1st blade part 3c is made to contact | connect a semiconductor ingot. Since the deterioration of the surface roughness caused by the vibration of the endless belt 2 and the contact of the blade portion with the cut surface can be suppressed, the semiconductor ingot 6 having a smaller cut surface and a good semiconductor ingot 6 can be obtained. Obtainable.

  In the semiconductor ingot 6 cut by such a band saw type cutting machine 1, the occurrence of chipping, cracking, cracking, etc. is suppressed in the slicing step and cell forming step, and the problem of a decrease in product yield can be suppressed. it can.

  Next, a band saw type cutting machine according to a second embodiment of the present invention will be described. FIG. 10 is a diagram showing an outline of a second embodiment of the band saw type cutting machine according to the present invention, wherein 1 is a band saw type cutting machine, 2 is an endless belt, 3 is a first blade portion, and 4 is a second blade. And 5a are pulleys, 6a is a semiconductor ingot provided at the bottom of the band saw, and 6b is a semiconductor ingot provided at the top of the band saw.

  In the band saw type cutting machine according to the second embodiment of the present invention, as shown in FIG. 10, the first blade portion 3 is on both edges of the endless belt 2 and cuts the semiconductor ingots 6a and 6b. It is characterized by having a mechanism for moving it.

  And the arrangement | positioning method of these blade parts 3 can apply arrangement | positioning of the blade part of 1st embodiment mentioned above.

  For example, the 1st blade part 3 and the 2nd blade part 4 are arrange | positioned at the edge part of both of the endless belt 2, and move the endless belt 2 with respect to the direction which cut | disconnects the semiconductor ingots 6a and 6b. Therefore, the effects of the first embodiment of the present invention can be obtained, and the semiconductor ingots 6a and 6b can be cut more efficiently.

  FIG. 11A and FIG. 11B are examples of the arrangement of the first blade portion 3 and the second blade portion 4 according to the second embodiment of the present invention. The arrangement positions of the first blade portion 3 and the second blade portion 4 shown in FIG. 11 (a) are based on FIG. 7 (a) shown in the third example of the first embodiment of the present invention. The blade part 3 and the second blade part 4 are arranged at both edges of the endless belt 2.

  Here, as shown in FIG. 11 (a), the blade portion may be provided symmetrically in the vertical direction, and as shown in FIG. 11 (b), the phase of the edge portion provided with the blade portion is higher than that in FIG. 11 (a). It does not matter even if it is shifted. Moreover, you may arrange | position the blade part formed from the abrasive grain from which an upper and lower edge part respectively differs in a particle size as arrangement | positioning of the blade part as shown in 1st embodiment of this invention.

  In this way, a semiconductor ingot 6a and a semiconductor ingot 6b are prepared as a plurality of semiconductor ingots 6, and a mechanism for moving the endless belt 2 in the direction of cutting the semiconductor ingot 6a and the semiconductor ingot 6b is provided. By having it, the some semiconductor ingot 6 can be cut | disconnected more efficiently.

  As a mechanism for moving the endless belt, the following method can be considered.

(A) The position of the band saw of the band saw type cutting machine is fixed, the semiconductor ingot is fixed on a parallel movable table, and the semiconductor ingot is moved by moving the table itself to which the semiconductor ingot is fixed. Mechanism (b) The semiconductor ingot is fixed and can be translated in the longitudinal direction based on the pulley constituting the band saw type cutting machine, and the position of the endless belt is translated up and down to Below, the band saw type cutting machine 1 provided with the moving mechanism according to (b) described above for the moving mechanism of the endless belt 2 according to the second embodiment of the present invention will be described.

  In the second embodiment of the present invention, first, the endless belt 2 is translated downward, and the semiconductor ingot 6a placed under the band saw type cutting machine 1 is cut. After the cutting, the endless belt 2 is translated upward, the endless belt 2 is pulled out from the semiconductor ingot 6a, and the semiconductor ingot 6b placed on the endless belt 2 is cut as it is. Then, while the semiconductor ingot 6b placed above the endless belt 2 is being cut, the semiconductor ingot 6a placed under the endless belt 2 is taken out, and the semiconductor ingot 6c to be newly cut. Is placed under the endless belt 2, and the semiconductor ingot 6 b placed on the endless belt 2 is cut, and then the endless belt 2 is again translated downward to move the endless belt 2 to the semiconductor ingot. The semiconductor ingot 6c newly pulled out from 6b and placed under the endless belt 2 is cut as it is.

  By using such a band saw type cutting machine 1, it is possible to reduce the time required for the cutting process by placing a new semiconductor ingot 6b during the cutting of the semiconductor ingot 6a, thereby improving productivity. Can be made. Furthermore, since the first blade portion 3 and the second blade portion 4 are arranged in the endless belt 2, as described above, the first blade portion 3 has a high cutting ability, so that the semiconductor ingots 6a and 6b are disposed. By cutting efficiently, the second blade portion 4 having a surface roughness smaller than that of the first blade portion 3 can provide a cutting surface having a good surface roughness.

  As a result, chipping, cracking, cracking, and the like are suppressed in the subsequent slicing process and cell forming process for a semiconductor wafer, and the problem of reduced product yield can be suppressed.

  In addition, the first blade portion 3 described above includes at least a first abrasive grain on the outer surface thereof, and the second blade portion 4 includes a second blade portion 4 having a particle diameter smaller than that of the first abrasive grain at least on the outer surface thereof. It is preferable to include two abrasive grains. This is because the grain size is defined for the abrasive grains, and the surface roughness of the cut surface of the semiconductor ingot 6 can be processed to a desired surface roughness by selecting the grain size of the abrasive grains forming the blade portion. It is.

  Moreover, after the 1st blade part 3 contact | connects the semiconductor ingot 6, the 2nd blade part 4 formed from the abrasive grain smaller than the 1st blade part 3 is made to contact the semiconductor ingot 6. FIG. Thus, the deterioration of the surface roughness caused by the vibration of the endless belt 2 and the contact of the blade portion with the cut surface can be suppressed. Can be obtained.

  Here, the arrangement position of the first blade portion 3 on the endless belt applied to the second embodiment of the present invention is limited to the first example to the third example given in the first embodiment of the present invention. There is no need to obtain the effect of the present invention even if the first blade portion 3 and the second blade portion 4 are arranged at various positions.

  Moreover, the 1st abrasive grain and the 2nd abrasive grain which comprise the 1st blade part 3 and the 2nd blade part 4 which were mentioned above about 1st embodiment and 2nd embodiment which concern on this invention are respectively the following. A range is desirable.

  The grain size of the first abrasive grain is set to # 40 or more and # 200 or less, and the grain size of the second abrasive grain is set to 1.3 times or more of the grain size of the first abrasive grain. By setting the first abrasive grains to be # 40 or more and # 200 or less, the cutting ability can be increased, and the semiconductor ingot can be efficiently cut. Then, the second abrasive grain having a second abrasive grain of 1.3 times or more of the grain size of the first abrasive grain can finish the cut surface compared to the first blade part, and the surface roughness Can be obtained.

  Further, it is more desirable that the grain size of the first abrasive grain is # 80 to # 120 and the grain size of the second abrasive grain is # 120 to # 1000. By setting the first abrasive grain to # 80 or more and # 120 or less, the cutting ability can be increased, and the semiconductor ingot can be efficiently cut. And by the 2nd blade part which made the 2nd abrasive grain # 120 or more and # 1000 or less, a finishing process can be carried out to a cut surface and what has good surface roughness can be obtained.

  Moreover, by setting it as the said range, after the 1st blade part 3 contact | connects the semiconductor ingot 6, the 2nd blade part 4 formed from the abrasive grain smaller than the 1st blade part 3 is semiconductor casting. Since it can be made to contact the lump 6 and the deterioration of the surface roughness caused by the vibration of the endless belt 2 and the contact of the blade portion with the cutting surface can be suppressed, the surface roughness of the cutting surface can be further reduced. The semiconductor ingot 6 having a small size can be obtained.

  In a semiconductor ingot cut by such a band saw type cutting machine, generation of chips, cracks, cracks, and the like is suppressed in the slicing step and cell forming step, and the problem of a decrease in product yield can be suppressed.

  Next, a method for cutting the semiconductor ingot 6 using the band saw type cutting machine 1 according to the present invention will be described in detail.

  A schematic diagram of a general band saw type cutting machine according to the present invention is shown in FIG. 1 is a band saw type cutting machine, 2 is an endless belt, 3 is a first blade portion, 4 is a second blade portion, 5 is a pulley, and 6 is a semiconductor ingot.

  The band saw type cutting machine 1 is moved in parallel in the width direction of the endless belt 2 while the band saw type cutting machine 1 is driven to rotate by the rotational drive of the pulley 5 in a state where tension is applied by pulling the two pulleys 5. The semiconductor ingot 6 is cut by pressing the band saw type cutting machine 1 against the semiconductor ingot 6 placed below the band saw type cutting machine 1.

A method of cutting the semiconductor ingot 6 using the band saw type cutting machine 1 according to the present invention described above,
(1) A first step of cutting the semiconductor ingot with the first blade portion 3 (2) A second step of finishing the cut surface of the semiconductor ingot 6 with the second blade portion 4 is included. did.

  As a result, since the first blade 3 has a high cutting ability, the semiconductor ingot 6 can be efficiently cut, and the second blade 4 can provide a semiconductor cutting method in which the surface roughness of the cut surface is good. it can.

  Then, after the first blade portion 3 is in contact with the semiconductor ingot 6, the second blade portion 4 is in contact with the semiconductor ingot 6, so that the endless belt 2 receives vibration and the blade portion is cut. Since the deterioration of the surface roughness due to contact with the surface can be suppressed, it is possible to provide a semiconductor cutting method in which the surface roughness of the cut surface is further good.

  As described above, the endless belt 2 may be provided using three or more types of blades. For example, the blades formed from abrasive grains are used to form the abrasive grains having the largest particle diameter. The first blade portion 3 thus cut first cuts the semiconductor ingot, and the second blade portion 4 formed of the smallest grain size cuts the semiconductor ingot last. As the blade portion is formed from abrasive grains having a large particle size, the blade portion that is mounted at a position away from the semiconductor ingot and that is formed from abrasive particles having a large particle size is first cast into the semiconductor casting. Cutting may be performed by contacting the lump, and then a blade portion formed of abrasive grains having a small particle diameter may be sequentially brought into contact with the semiconductor ingot. Further, for example, although not shown, a blade portion formed from five types of abrasive grains having different particle sizes is prepared, and cutting blade portions 3p, 3q, 3r (particle size) formed from abrasive grains having a large particle size are prepared. 3p> 3q> 3r), the semiconductor ingot is cut from the larger one, and then the finishing blades 4p, 4q (4p> 4q from the larger particle diameter) formed from abrasive grains having a small particle diameter. Then, the finishing process may be performed on the cut surface of the semiconductor ingot, and the order of contacting the semiconductor ingot in the blade portions 3p, 3q, and 3r and in the blade portions 4p and 4q is not particularly mentioned.

  In a semiconductor ingot cut by such a band saw type cutting machine, generation of chips, cracks, cracks, and the like is suppressed in the slicing step and cell forming step, and the problem of a decrease in product yield can be suppressed.

  The number of pulleys 5 is not limited to two, and there may be a plurality of pulleys. By making the edge of the endless belt 2 polygonal, the cutting position of the semiconductor ingot 6 is also increased, and the productivity is improved.

  Further, by increasing the degree of freedom in the moving direction of the band saw type cutting machine, it is possible to provide not only a vertical movement but also a three-dimensional moving mechanism.

  Furthermore, the arrangement of the blade portion of the endless belt shown in the present invention is only an example, and it goes without saying that the arrangement position of the blade portion is changed as necessary. For example, as shown in FIG. 2, it is not necessary to alternately mount the first blade portion 3a and the second blade portion 4a, and two second blades are continuously provided between the first blade portions 3a. The part 4a may be attached. Further, it is not necessary to attach the same number of first blade parts 3 and second blade parts 4 to the endless belt 2, and the number of blade parts is set in consideration of the surface roughness and cutting speed of the cutting surface. do it.

  Moreover, although the example which used the blade part formed from the abrasive grain was given in the above-mentioned description, it is not necessary to cut | disconnect only using the blade part formed from the abrasive grain, For example, in the 1st blade part 3 A blade portion made of a carbide tool may be used, and a blade portion made of abrasive grains may be used in combination with the second blade portion 4.

  As shown in FIG. 2 as Example 1, the first blade 3 formed from the first abrasive grains at the edge of the endless belt 2 made of high-strength steel, and the particle diameter from the first abrasive grains. A band saw type cutting machine 1 equipped with a second blade portion 4 formed from a small second abrasive grain was prepared. Further, as shown in FIG. 7B as Example 2, the first blade 3c is provided at the edge of the endless belt 2 made of high-strength steel, and the first blade 3c is the second. The semiconductor ingot 6 was contacted before the blade portion 4c. The endless belt 2 on which the first blade portion 3c and the second blade portion 4c are disposed is installed between the pulleys 5 as shown in FIG. This band saw type cutting machine 1 is a metal band saw type cutting machine and has an advantage that it is easier to manufacture than an electrodeposition band saw.

  In Example 1 and Example 2 according to the present invention, diamond abrasive grains were used for both the first abrasive grains and the second abrasive grains. The grain size of the first abrasive grain was set to # 100, and the grain size of the second abrasive grain was set to # 800. Using these band saw type cutting machines 1, a semiconductor ingot 6 (polycrystalline silicon ingot) having a vertical width, a horizontal width of 320 mm, and a height of 310 mm was cut in the height direction at a cutting speed of 10 mm / min. . And the 10-point average surface roughness Rz of the cut surface at this time was measured about Example 1 and Example 2. FIG.

  As Comparative Example 1, as shown in FIG. 13, similarly, using a band saw type cutting machine 11 in which a blade portion 13 formed of abrasive grains is attached to one end of an endless belt 2 made of high-strength steel, the cutting speed is similarly set. The polycrystalline silicon ingot was cut at 10 mm / min, and the 10-point average surface roughness Rz of the cut surface at this time was measured. The band saw type cutting machine 11 is a metal band saw type cutting machine. The abrasive grains are diamond abrasive grains, and the grain size is # 100.

  As Comparative Example 2, as shown in FIG. 15, blade portions (23b, 23c) having different blade heights are attached to one end of an endless belt 2 made of high-strength steel, and the blade portion 23c having a low blade edge is cut. Using a band saw type cutter 21 having a width wider than the blade part 23b having a high cutting edge, the polycrystalline silicon ingot is similarly cut at a cutting speed of 10 mm / min, and the ten-point average surface roughness of the cut surface at this time is cut. The thickness Rz was measured. The band saw type cutting machine 1 is an electrodeposited band saw type cutting machine. The abrasive grains are diamond abrasive grains, and the grain size of the abrasive grains used in both blade portions (23b, 23c) is # 100. Moreover, in the blade part 23c with a low blade edge | tip, a nickel plating layer is provided as a base layer, and it forms so that the cutting width may become wider than the blade 23c with a high blade edge | tip.

In addition, a polycrystalline silicon ingot is cut into 150 mm square by each band saw type cutting machine, the cut polycrystalline silicon ingot is sliced by a multi-wire saw, and one piece of polycrystalline silicon is 250 μm thick. A substrate was produced. And the general bulk type solar cell was produced using the obtained polycrystalline silicon substrate. Yield concerning chipping, cracking and cracking when this slicing step and cell forming step were performed was evaluated. These results are shown in Table 1.

  From Table 1, in Comparative Example 1, the 10-point average surface roughness Rz of the cut surface was 10.4 μm, and the 10-point average surface roughness Rz of Comparative Example 2 was 8.3 μm. It can be seen that the ten-point average surface roughness Rz is 6.9 μm, and in Example 2, the ten-point average surface roughness Rz is significantly improved to 5.0 μm. The electrodeposition band saw type cutting machine used in Comparative Example 2 had a reduced cutting ability and a reduced surface roughness when the cutting process was repeated. However, the metal band saw type cutting machine used in the example reduced the cutting ability. There was no decrease in surface roughness.

  Further, when solar cells were produced using semiconductor ingots (polycrystalline silicon ingots) cut by the respective band saw type cutting machines, the yield relating to chipping, cracking and cracking at that time was the yield of Comparative Example 89. %, Which was slightly improved at 90% in Comparative Example 2, but was significantly improved to 93% in Example 1 and 95% in Example 2.

It is the schematic of 1st embodiment of the band saw type cutting machine which concerns on this invention. It is a 1st example of arrangement | positioning of the blade part which concerns on 1st embodiment of this invention. It is a mode that the semiconductor ingot was cut | disconnected by arrangement | positioning of the 1st blade part shown in Fig.2 (a), and a 2nd blade part. It is a mode that the semiconductor ingot was cut | disconnected by arrangement | positioning of the 1st blade part shown in FIG.2 (b), and a 2nd blade part. It is a 2nd example of arrangement | positioning of the blade part which concerns on 1st embodiment of this invention. It is a mode that the semiconductor ingot was cut | disconnected by arrangement | positioning of the 1st blade part shown in FIG. 5, and the 2nd blade part. It is a 3rd example of arrangement | positioning of the blade part which concerns on 1st embodiment of this invention. It is a mode that the semiconductor ingot was cut | disconnected by arrangement | positioning of the 1st blade part shown in FIG. 7, and the 2nd blade part. It is a mode that the thickness of a blade part was changed and the semiconductor ingot was cut | disconnected in the 4th example of arrangement | positioning of the blade part which concerns on 1st embodiment of this invention. It is the schematic of 2nd embodiment of the band saw type cutting machine which concerns on this invention. It is an example of arrangement | positioning of the 1st blade part which concerns on 2nd embodiment of this invention, and a 2nd blade part. It is the schematic which shows the structure of the conventional band saw type | mold cutting machine. It is an example of arrangement | positioning of the blade part of the conventional band saw type cutting machine. It is a mode that the semiconductor ingot was cut | disconnected by arrangement | positioning of the blade part shown in FIG. It is another example of arrangement | positioning of the blade part of the conventional band saw type cutting machine. It is a mode that the semiconductor ingot was cut | disconnected by arrangement | positioning of the blade part shown in FIG.

Explanation of symbols

1: Band saw type cutting machine 2: Endless belt 3: First blade portion 3a: First blade portion having a shape shorter than 4a in the endless belt width direction 3b: First shape having a shape longer than 4b in the endless belt width direction Blade portion 3c: first blade portion having a shape thinner than 4c in the endless belt thickness direction 4: second blade portion 4a: second blade portion having a shape longer than 3a in the endless belt width direction 4b: endless Second blade portion having a shape shorter than 3b in the belt width direction 4c: Second blade portion having a shape thicker than 3c in the endless belt thickness direction 5: Pulley 6: Semiconductor ingot in the first embodiment 6a: First Semiconductor ingot provided in the lower part of the band saw type cutting machine in the second embodiment 6b: Semiconductor ingot provided in the upper part of the band saw type cutting machine in the second embodiment

Claims (9)

A plurality of blade portions for cutting the semiconductor ingot are arranged on the endless belt, and the endless belt and the semiconductor ingot are relatively moved while rotating the endless belt, and the width direction of the endless belt A band saw type cutting machine for cutting the semiconductor ingot,
The plurality of blade portions are band saw type cutting machines including a first blade portion disposed at an edge portion of the endless belt and a second blade portion having a surface roughness smaller than that of the first blade portion. The band saw type cutting machine according to claim 1, wherein the second blade portion is disposed on an outer surface of the endless belt excluding the front end portion in the cutting direction. The band saw type cutting machine according to claim 1 or 2, wherein the first blade portion is disposed on the endless belt at a position in contact with the semiconductor ingot prior to the second blade portion. . The band saw type cutting machine according to any one of claims 1 to 3, wherein the second blade portion projects outward from the first blade portion in the thickness direction of the endless belt. The endless belt includes the first blade portion on both edges thereof,
The band saw type cutting machine according to any one of claims 1 to 4, further comprising a mechanism for moving the endless belt with respect to a direction in which the semiconductor ingot is cut. The first blade part includes at least a first abrasive grain on an outer surface thereof,
The band saw type cutting according to any one of claims 1 to 5, wherein the second blade portion includes a second abrasive grain having a particle size smaller than that of the first abrasive grain on at least an outer surface thereof. Machine. The particle size of the first abrasive grain is set to # 40 or more and # 200 or less,
The band saw type cutting machine according to claim 6, wherein the particle size of the second abrasive grains is 1.3 times or more of the particle size of the first abrasive grains. The particle size of the first abrasive grains is # 80 or more and # 120 or less,
The band saw type cutting machine according to claim 6, wherein the second abrasive grains have a particle size of # 120 or more and # 1000 or less. A method for cutting a semiconductor ingot using the band saw type cutting machine according to any one of claims 1 to 8,
A first step of cutting the semiconductor ingot with the first blade portion;
A second step of finishing the cut surface of the semiconductor ingot with the second blade portion;
A method for cutting a semiconductor ingot.

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