JP2005153035A - Wire saw equipment - Google Patents

Abstract

An object of the present invention is to eliminate the need for complicated processes, at a low cost, and to maintain a high ability to hold abrasive slurry on the surface of the wire without deteriorating the wire, so that the semiconductor substrate is not contaminated during cutting. Provide a wire saw device.
A semiconductor substrate is formed by cutting a semiconductor ingot 3 by moving a wire 6 of a metal wire having a plating layer on the surface at a high speed and pressing the wire 6 against the semiconductor ingot 3 while supplying abrasive slurry. A rubbing body 10 that rubs against the wire 6 and removes the plating layer before the point where the wire 6 and the semiconductor ingot 3 come into contact with each other on the wire 6 path. Be prepared.
[Selection] Figure 1

Description

  The present invention relates to a wire saw device for manufacturing a semiconductor substrate that can be suitably used for, for example, a solar cell semiconductor substrate by cutting a semiconductor ingot.

  Conventionally, when a semiconductor substrate for a solar cell is formed using polycrystalline silicon or the like, for example, a polycrystalline silicon ingot is formed by a casting method, and the ingot is cut into a predetermined dimension to form a semiconductor ingot. The semiconductor ingot was formed by cutting a plurality of pieces with a wire saw device.

  FIG. 7 is a diagram for explaining a wire saw device according to the prior art.

  As shown in FIG. 7, the wire saw device used when cutting the semiconductor ingot has the semiconductor ingot 3 installed therein, and when cutting the semiconductor ingot, oil or water called abrasive slurry from a plurality of locations above is SiC or the like. A cutting fluid mixed with a plurality of abrasive grains is supplied, and a single wire 6 made of a piano wire or the like having a diameter of about 100 to 300 μm is fitted at regular intervals provided on the main roller 5 from the wire supply reel 9. It is wound around a number of grooves and arranged parallel to each other.

  That is, when the semiconductor ingot 3 is cut, the abrasive slurry is supplied from above and the plurality of wires 6 stretched between the two main rollers 5 are moved at high speed while the plurality of semiconductor ingots 3 are connected to the wires 6. The semiconductor ingot 3 is cut by being lowered gradually toward the surface and pressed against the semiconductor ingot 3 to produce a semiconductor substrate.

  With this wire saw device, a large number of semiconductor ingots 3 can be cut at the same time, and the cutting accuracy is high compared to other cutting methods using an outer peripheral blade or an inner peripheral blade. Since it is thin, there is an advantage that kerf loss (cutting loss) can be reduced.

In the manufacturing process of the wire 6 used in such a conventional wire saw device, the surface of the wire 6 is subjected to a brass plating process mainly composed of copper and zinc. The reason for applying this brass plating treatment is to provide a rust prevention effect, to obtain a lubricating effect when the wire 6 is passed through the die, particularly in the wire drawing process for drawing the wire 6, and to prevent the die from being worn. It is. Therefore, if the surface of the wire 6 is not subjected to brass plating, the wire 6 and the die are poorly lubricated when the wire 6 is stretched through the die. As a result, scratches occur and the quality deteriorates. In addition, since the wear of the die is accelerated and the productivity is deteriorated, the brass plating process is indispensable when the wire 6 is manufactured.
Japanese Patent Laid-Open No. 11-10514 Japanese Patent Laid-Open No. 9-254006 JP 9-254145 A

  As described above, the wire 6 is subjected to the brass plating process, which makes the surface of the wire 6 very smooth, and the ability to hold the abrasive slurry even if it is supplied to the surface of the wire 6 is weak. And since the wire 6 is traveling at high speed, the abrasive slurry falls immediately below. For this reason, the abrasive slurry is hardly supplied to the contact portion between the wire 6 and the semiconductor ingot 3, and there is a problem that the cutting speed cannot be increased.

  Moreover, when the plating layer on the surface of the wire 6 adheres to the semiconductor substrate, the substrate is contaminated with metal impurities, etc., and used as a semiconductor substrate for a solar cell, the characteristics of the solar cell are deteriorated and sufficient efficiency is obtained. There was also a problem that it could not be obtained. For example, if a semiconductor silicon ingot is cut when the surface of the wire 6 is plated with copper or a copper alloy, copper has a larger diffusion coefficient in silicon than iron, which is the material of the wire. Due to the heat generation, copper may diffuse into the silicon from the cut surface. Thus, it is difficult to remove the metal impurities once diffused by a cleaning process or an etching process after the cutting.

  In order to solve such a problem, Patent Document 1 discloses a wire having a helically twisted shape and having a concave portion, a groove, or a hole that can hold an abrasive slurry on its surface. . Furthermore, Patent Document 2 discloses the content of making the cross-sectional shape with respect to the central axis of the wire polygonal or elliptical, or making a plurality of strands used for the wire twisted. By making the wire into the shape as described above, the ability to hold the abrasive slurry on the wire surface can be enhanced. However, there is a problem that the processing of the wire takes man-hours and is expensive. Further, the problem that metal impurities in the plating layer diffuse into the semiconductor substrate cannot be solved.

  In Patent Document 3, after a copper or copper alloy plating layer is formed on the surface of the wire and the final finish is drawn, copper or copper alloy is formed by any combination of chemical polishing, physical polishing, and electric field polishing. By peeling the gold plating layer, the wire is smoothly lubricated and the surface of the wire is not easily damaged, so the quality of the wire is not deteriorated, and then the copper or copper alloy is plated on the surface of the wire. It is disclosed that a cut wafer or the like is not contaminated with a metal impurity or the like by peeling the layer and using it for a wire device. However, when the above polishing method is used, for example, in physical polishing, the copper or copper alloy plating layer is peeled and then washed with a cleaning solution, and the wire is wound through a water washing and rust prevention process. There was a problem of becoming.

  In physical polishing, for example, it is difficult to completely remove the plating layer by spraying a grindstone, abrasive cloth with abrasive grains, or sandblasting, and the surface of the wire may be damaged, or the wire may be cut and thinned. There is also a possibility to do. Also, after roughly removing the plating layer by physical polishing, if the plating layer is completely peeled by chemical polishing, the portion of the wire surface without the plating layer is chemically treated during chemical polishing, There was a problem that the quality of the wire deteriorated.

  The present invention has been made in view of such problems of the prior art, and does not require a complicated process, is low in cost, and has a high ability to hold the abrasive slurry on the wire surface without deteriorating the wire. An object of the present invention is to provide a wire saw device that can be maintained and does not contaminate a semiconductor substrate during cutting.

  In order to achieve the above object, a wire saw device according to claim 1 of the present invention moves a wire of a metal wire having a plating layer on its surface at a high speed and supplies an abrasive slurry to a semiconductor ingot. A wire saw device that forms a semiconductor substrate by cutting the semiconductor ingot by pressing, wherein the wire and the semiconductor ingot are placed on the path of the wire before the contact point between the wire and the semiconductor ingot. A rubbing body for removing the plating layer by rubbing is provided.

  Since it was set as such a structure, the operation | movement which peels the plating layer of the wire surface with a rubbing body, and the operation | movement which cut | disconnects a semiconductor ingot can be performed simultaneously simultaneously. Moreover, since the plating layer on the wire surface peels and the smoothness of the wire surface decreases, the ability to hold the abrasive slurry on the wire surface is improved. Furthermore, since the plating layer on the wire surface is not peeled off immediately before cutting, the effect of protecting the wire surface can be maximized.

  Moreover, the wire saw apparatus according to claim 2 of the present invention is the wire saw apparatus according to claim 1, wherein the wire is a metal wire mainly composed of iron or an iron alloy, and the plating layer includes copper and zinc. Since it is a brass plating layer mainly composed of, it is possible to obtain a low-cost and high-performance wire.

  A wire saw device according to a third aspect of the present invention is the wire saw device according to the first or second aspect, wherein the wire cuts the rubbing body simultaneously with cutting the semiconductor ingot. Therefore, the wire plating layer can always be peeled off at a new portion of the rubbing body.

  A wire saw device according to a fourth aspect of the present invention is the wire saw device according to the third aspect, wherein the rubbing body is fixed in contact with the semiconductor ingot. And the semiconductor ingot can be handled as one body, and the respective positions are determined stably. For this reason, the rubbing body can be stably operated by an extremely simple process.

  The wire saw device according to claim 5 of the present invention is the wire saw device according to any one of claims 1 to 4, wherein the rubbing body is made of glass as a main component, so Almost no damage is done.

  In the present invention, rubbing refers to rubbing in a state of contact with each other.

  As described above, according to the wire saw device according to the first aspect of the present invention, the operation of peeling the plating layer on the surface of the wire by the rubbing body and the operation of cutting the semiconductor ingot are performed simultaneously. In addition to being efficient, the semiconductor ingot is cut while the plating layer is peeled off, so that the cut semiconductor substrate is not contaminated. And with the peeling of the plating layer on the wire surface, the smoothness of the wire surface decreases, so the ability to hold the abrasive slurry on the wire surface is improved, and the abrasive slurry supply to the contact portion between the wire and the semiconductor ingot The amount can be increased, the cutting speed can be increased and the cutting time can be shortened. In particular, when the wire is used a plurality of times, the yield rate at the first use is increased, and the productivity is improved. Furthermore, since the plating layer on the wire surface is not peeled until immediately before cutting, the effect of protecting the wire surface can be maximized, and deterioration due to oxidation or rusting of the wire can be prevented.

  According to the wire saw device of the second aspect of the present invention, the wire is a metal wire mainly composed of iron or an iron alloy, and the plating layer is a brass plating layer mainly composed of copper and zinc. It can be a low-cost and high-performance wire, and can have high productivity and low cost.

  And according to the wire saw apparatus concerning Claim 3 of this invention, since the plating layer of a wire can always be peeled in the new part of a rubbing body, the surface of the wire from which the plating layer was peeled is uniform and stable. It will be in the state. As a result, the holding ability of the abrasive slurry is stabilized, and the cutting speed and cutting state can be made uniform and stable.

  Furthermore, according to the wire saw device according to claim 4 of the present invention, since the rubbing body is fixed in contact with the semiconductor ingot, the rubbing body and the semiconductor ingot can be handled as a unit, The position of is stable. Accordingly, the operation as a rubbing body can be performed stably at a low cost without complicating the process.

  Further, according to the wire saw device of claim 5 of the present invention, the glass rubbing body is easily cut by the wire, and at the same time, the plating layer can be reliably removed from the surface of the wire. In most cases, the wire is not damaged, the surface of the wire is not damaged, the wire is not cut and thinned, and the wire can have a long life.

  As described above, according to the wire saw device of the present invention, a large amount of semiconductor substrate can be obtained with high productivity and low cost, and the characteristics of the semiconductor substrate can be adversely affected by adhesion of metal components of plating. Therefore, it is extremely suitable for the production of a semiconductor substrate for a solar cell that requires a large amount of semiconductor substrate and requires high quality.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing a wire saw device according to the present invention, and FIG. 2 is a schematic view showing a cut state of the wire saw device. 1 and 2, 1 is a slurry nozzle, 2 is a slurry receiver, 3 is a semiconductor ingot, 4 is a slicing base, 5 is a main roller, 6 is a wire, 6a is a brass plating layer, 7 is an end material entrainment prevention plate, 8 Is a dip tank, 9 is a wire supply reel, and 10 is a glass plate which is an example of a rubbing body in the present invention.

  As shown in FIG. 1, the wire saw device includes a plurality of slurry receivers 2 arranged side by side under a slurry nozzle 1, and a semiconductor bonded to a slicing base 4 with an epoxy resin or the like between these slurry receivers. By placing the ingot 3 and supplying abrasive slurry to the plurality of wires 6 between the main rollers 5 while moving the wire 6 at a high speed, the semiconductor ingot 3 is gradually lowered and pressed against the wire 6, The semiconductor ingot 3 is cut to obtain a plurality of semiconductor substrates. Further, an end material entrainment prevention plate 7 is provided to prevent the end material of the semiconductor substrate that may fall during cutting from being caught in the main roller 5, and a dip tank 8 is provided for the case where the end material cannot be prevented. ing. The dip tank 8 also has a purpose of collecting chips generated when the abrasive slurry is collected or cut.

  The slurry receiver 2 at the lower part of the slurry nozzle 1 is provided so that the abrasive slurry can be supplied evenly to the wires 6 stretched in a uniform manner without any unevenness. A wrapping oil composed of an activator and a dispersant is mixed.

  The semiconductor ingot 3 is configured by, for example, a polycrystalline silicon ingot formed by a casting method or the like cut into a rectangular parallelepiped having a predetermined size, for example, 150 × 150 × 300 mm. An adhesive such as an epoxy resin is applied to one surface of the semiconductor ingot 3 and adhered to a slice base 4 made of a carbon material or a glass material. Therefore, the semiconductor ingot does not fall apart even if it is cut, and is put into the next cleaning process in that state.

  In the washing process, the sludge and the like adhering at the time of slicing are first removed by washing with kerosene. After that, wipe the oil with an alkaline detergent, and then wash away the detergent with water. Then, the substrate surface is completely dried by hot air or air, and then peeled off from the slicing base to complete the semiconductor substrate.

  The main roller 5 is made of urethane rubber having a diameter of 200 to 350 mm and a length of 400 to 500 mm, for example, and a plurality of grooves (not shown) in which the wires 6 are fitted at predetermined intervals of about 400 to 600 μm are formed on the surface. . The thickness of the semiconductor substrate as the final product is determined by the relationship between the groove interval and the diameter of the wire 6.

  The wires 6 are supplied from the wire supply reel 9 and are wound and arranged in grooves with a predetermined interval provided on the main roller 5. The wire 6 is, for example, a piano wire mainly composed of iron or an iron alloy having a diameter of about 140 to 180 μm. In a new state, the wire 6 is mainly composed of copper and zinc described in JIS G 3502 SWRS82A. A brass plating layer 6a (shown in FIG. 2) is formed on the surface, and the surface is extremely smooth. The wire 6 can be moved and moved by rotating the main roller 5 at a predetermined rotation speed, and is usually moved and moved at a high speed so as to be about 400 to 700 m / min.

  In the wire saw device according to the present invention, as shown in FIG. 1 or 2, as a rubbing body, for example, a thickness of 5 mm to 20 mm on the end surface side of the semiconductor ingot 3 on the wire 6 supply side on the path of the wire 6. The glass plate 10 is bonded to the slicing base 4 with an epoxy resin or the like and fixed in a state where the glass plate 10 is in contact with the semiconductor ingot 3. Rubbed by the plate 10.

  Thereby, when the wire 6 passes through the glass plate 10 and is rubbed, the brass plating layer 6a applied to the surface of the wire is scraped and removed. As a result, the ability to hold the abrasive slurry on the surface of the wire 6 is enhanced. Then, since the wire 6 contacts and passes the semiconductor ingot 3, the abrasive slurry supply amount to the contact part of the wire 6 and the semiconductor ingot 3 increases. Therefore, the cutting speed can be increased and the cutting time can be shortened.

  And since the operation | movement which peels the brass plating layer 6a on the surface of the wire 6 by the glass plate 10 which is a rubbing body, and the operation | movement which cut | disconnects the semiconductor ingot 3 can be performed simultaneously simultaneously, it is very efficient, Since the semiconductor ingot 3 is cut while the brass plating layer 6a is peeled off, the cut semiconductor substrate is not contaminated by a metal or the like contained in the brass plating layer 6a. Furthermore, since the brass plating layer 6a on the surface of the wire 6 is not peeled until immediately before cutting, the effect of protecting the surface of the wire 6 can be maximized, and deterioration due to oxidation or rusting of the wire 6 can be prevented. Can do.

  In particular, in the conventional wire saw device, because of the brass plating layer 6a on the surface of the wire 6, the yield of non-defective products when using the wire 6 for the first time was poor. By passing and rubbing, the brass plating layer 6a on the surface of the wire 6 is peeled off, and the ability to hold the abrasive slurry on the surface of the wire 6 is increased, so that the yield rate of the non-defective product at the first use increases. Improves.

  The brass plating layer 6a peeled off from the wire surface is caused to flow by the supplied abrasive slurry, and the wire 6 passes through the semiconductor ingot 3 immediately after the brass plating layer 6a on the wire surface peels off. After peeling 6a, it is unnecessary to go through washing with water and rust prevention process. Therefore, a semiconductor substrate can be formed at low cost and without complicated processes.

  By the way, the peeled brass plating layer 6a accumulates in the recovered abrasive slurry, and the metal impurities contained in the brass plating layer 6a directly contact the cut surface of the semiconductor ingot 3 to contaminate the cut semiconductor substrate. There is a possibility. However, since such metal impurities are not diffused and adhered to the semiconductor substrate, the cut semiconductor substrate is washed, or the damaged layer on the surface caused by the cutting is removed by alkali etching or the like. In such a process, a portion contaminated with metal impurities can be removed.

  Moreover, as an example of the rubbing body, an example using the glass plate 10 whose main component is glass has been described. The glass plate 10 described here is easily cut by the wire 6 made of a piano wire, and at the same time, the brass plating layer 6 a can be reliably removed from the surface of the wire 6. Therefore, for example, compared with the conventional example described in Patent Document 3, the surface of the wire 6 is damaged, the wire 6 is cut and thinned, or the wire 6 is chemically treated because no chemical polishing liquid is used. Only the brass plating layer 6a can be peeled off without deteriorating the quality of the wire 6, and the wire 6 can have a long life.

  The material of the glass plate 10 is not particularly limited, and general glass materials such as soda glass, borosilicate glass, and quartz glass can be used, but they are extremely inexpensive and easily available. Therefore, it is more desirable to use soda glass.

  Further, as the rubbing body, in addition to a material mainly composed of glass, for example, when the semiconductor ingot is silicon, crystalline silicon, metal silicon, silicon carbide, or the like can be used. The chips are collected together with the abrasive slurry and repeatedly used. However, since the present invention slices the semiconductor ingot and the rubbing body at the same time, the rubbing chip is also mixed into the abrasive slurry. However, if a rubbing body made of the same element as the semiconductor ingot or a compound thereof is used, the semiconductor ingot will not be adversely affected even during repeated use.

  However, if the hardness is too high, the wire will be broken and the life will be shortened. If an expensive one is used, the cost will increase, so it is desirable to use glass.

  As shown in FIGS. 1 and 2, the wire 6 has a configuration in which the glass plate 10 is disposed at a position at which the glass plate 10 that is a rubbing body is cut at the same time as the semiconductor ingot 3 is cut. desirable. In this way, since the glass plate 10 is cut at the same time when the semiconductor ingot 3 is cut, the brass plating layer 6a of the wire 6 can always be peeled off at a new portion of the glass plate 10, so that the brass plating layer The surface of the wire 6 from which 6a has been peeled is in a uniform and stable state. As a result, the holding capacity of the abrasive slurry can be stabilized, and the cutting speed and cutting state can be kept uniform and stabilized. In order to obtain such a configuration, for example, the glass plate 10 is placed at the position shown in FIGS. 1 and 2 in a state where the size of the glass plate 10 is substantially equal to or slightly larger than the size of the end face of the semiconductor ingot 3. May be arranged.

  When the height of the glass plate 10 is the same as the height of the semiconductor ingot 3, the wire 6 that does not pass through the glass plate 10 initially contacts the semiconductor ingot 3. Since the wire 6 is traveling at an extremely high speed as compared with the descending speed of the semiconductor ingot 3, the semiconductor ingot 3 with which the wire 6 covered with the brass plating layer 6a comes into contact is very small. It does n’t come.

  However, if the height of the glass plate 10 is set higher than the height of the semiconductor ingot 3, the wire 6 from which the brass plating layer 6a has been peeled off from the semiconductor ingot 3 comes into contact with the semiconductor ingot 3 to completely eliminate the problem. Can be prevented.

  As shown in FIG. 2, in the case of a multi-wire saw device in which a plurality of wires 6 are arranged at predetermined intervals, the glass plate 10 that is a rubbing body is slid a plurality of times before the wires 6 contact the semiconductor ingot 3. You may arrange | position the glass plate 10 in the position which rubs. FIG. 2 shows an example in which the glass plate 10 is rubbed twice by the wire 6. If the wire 6 and the rubbing body (glass plate 10) are rubbed a plurality of times in this way, the brass plating layer 6a on the surface of the wire 6 can be reliably peeled and removed.

  The rubbing body is preferably fixed in contact with the semiconductor ingot 3. For example, in FIG. 1 and FIG. 2, the glass plate 10 that is a rubbing body is fixed to the slicing base 4 in a state of being in contact with the semiconductor ingot 3. In this way, since the glass plate 10 and the semiconductor ingot 3 can be handled as one body, not only the handling is easy, but even if the wire 6 is moved at a high speed, the glass plate 10 does not touch the position. Since it is in contact with the semiconductor ingot 3 in a stable state, the operation as a rubbing body can be performed stably at low cost without complicating the process.

  As described above, according to the wire saw device of the present invention, a large amount of semiconductor substrate can be obtained with high productivity and low cost, and the characteristics of the semiconductor substrate can be adversely affected by adhesion of metal components of plating. Therefore, it is extremely suitable for the production of a semiconductor substrate for a solar cell that requires a large amount of semiconductor substrate and requires high quality.

  It should be noted that the embodiment of the present invention is not limited to the above-described example, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

  For example, in the above description, the example of a multi-wire saw device that shears a semiconductor ingot by arranging a plurality of wires at a predetermined interval has been described. However, the present invention is not limited to this, and a single wire that performs cutting with a single wire is used. Even if it is a type of wire saw device, a rubbing body is provided before the point where the wire and the semiconductor ingot contact on the path of the wire, and the plating on the surface of this wire is rubbed and peeled off If configured to do so, the effects of the present invention are excellent.

  In the above description, the example in which the glass plate 10 of the rubbing body is fixed to the slicing base 4 while being in contact with the semiconductor ingot 3 has been described. However, for example, the glass plate 10 is not moved on the slicing base 4. If the holding mechanism is provided or the glass plate 10 itself is thickened so that it can be placed on the slicing table 4 in a stable state, it may be arranged at a distance from the semiconductor ingot 3.

  Further, for example, as shown in FIG. 3, the glass plate 10 of the rubbing body may be bonded to the surface of the semiconductor ingot 3 where the wire 6 first contacts. By doing in this way, the wire 6 which passed the glass plate 10 of the rubbing body reliably comes into contact with the semiconductor ingot 3. However, in this case, it is necessary to adhere the glass plate 10 of the rubbing body having an appropriate thickness in order to pass the glass plate 10 of the rubbing body through all the wires 6. Moreover, in order to make it easy to peel off the substrate and the glass plate after slicing, it is necessary to use, for example, an epoxy adhesive that dissolves in a solvent. By doing so, the substrate and the glass can be peeled off by chemical treatment without applying external force. Further, roughening the glass surface to be bonded to the semiconductor ingot 3 is also a measure for facilitating peeling.

  Further, as shown in FIG. 4, the effect of the present invention can also be obtained by disposing a glass plate 10 of a rubbing body on the side surface corresponding to the upstream side in the running direction of the wire 6 with respect to the semiconductor ingot 3. At this time, the glass plate 10 of the rubbing body may be adhered to the semiconductor ingot 3 or may be fixed to the slicing base 4.

  Further, in the present invention, the rubbing body 10 may be located on the path of the wire 6 and before the point where the wire 6 and the semiconductor ingot come into contact with each other, and may be bonded and fixed to the semiconductor ingot 3 or the slice table. For example, as shown in FIG. 5, it is also possible to provide a glass plate 10 of a rubbing body in the middle of the path of the wire 6.

  The brass plating layer 6 a coated on the surface of the wire 6 may not be completely removed by the rubbing body 10. Even if it is not completely removed, the wire 6 having the brass plating layer 6a on the surface that does not pass through the rubbing body 10 is used if it is thin or partially peeled off. This is because the brass plating layer 6a is more easily peeled off than the case, so that it is in contact with the semiconductor ingot 3 so that the brass plating layer 6a is very easily removed.

  Two polycrystalline silicon ingots are set as a semiconductor ingot 3 of 150 mm square × L = 280 mm in the wire saw apparatus of the present invention of the embodiment of FIG. 1, and the end surface of the polycrystalline silicon ingot 3 on the side to which the wire 6 is supplied is set. A glass plate 10 having a thickness of 10 mm and a height and width of 150 mm is attached to the ingot 3 and the slicing base 4 using an adhesive as a rubbing body, and a 0.2 μm diameter having a diameter of 180 μm is supplied while supplying an SiC abrasive slurry. The cutting test was carried out by running the piano wire 6 provided with the brass plating layer 6a at 500 m / min.

  Furthermore, the rubbing body was tested using a crystalline silicon plate of the same size instead of the glass plate.

  Moreover, the cutting test was similarly performed also in the wire saw apparatus of the present invention in each of the embodiments of FIGS. 3, 4, and 5. In the embodiment of FIGS. 3 and 4, a 150 mm × 280 mm glass plate was attached to one surface of the polycrystalline silicon ingot as a rubbing body, and the wire saw device of the present invention was tested. Further, in the embodiment of FIG. 5, a 30 mm square × 15 mm glass plate was installed as a rubbing body on the path of the wire 6, and the wire saw device of the present invention was tested.

  Further, as a comparative example, a test for cutting a polycrystalline silicon ingot was performed in the same manner with a conventional wire saw apparatus (FIG. 6) without a rubbing body.

  In addition, in order to clarify the effect of the present invention, the test was conducted by setting the feeding speed of the polycrystalline silicon ingot to 1.2 times the standard condition of the conventional wire saw apparatus shown in FIG.

The samples subjected to these cutting tests were evaluated based on the yield rate (%) and the presence or absence of metal impurities. Table 1 shows the results. As a method for calculating the yield rate of non-defective products, the cut wafer was observed with 50 metal microscopes to confirm the presence of chipping at the edge of the wafer. The presence of metal impurities on the cut surface was confirmed by XMA (X-ray microanalyzer).

  As shown in Table 1, in the conventional wire saw apparatus, since the workpiece feeding speed is large, chipping was observed on the cut wafer, and metal impurities originating from the brass plating layer 6a of the wire 6 were detected. . On the other hand, in the wire saw apparatus according to the present invention, the yield of non-defective products was 95% or more, and no metal impurities were detected from the cut surface, even though the workpiece feeding speed was increased.

  Thus, according to the wire saw device of the present invention, the brass plating layer 6a is cut from the surface of the wire 6 while being peeled off, so that the ability to hold the abrasive slurry on the surface of the wire 6 can be kept high, and as a result. It was confirmed that high cutting ability was obtained and that the cut substrate was not contaminated by metal impurities. In addition, it was confirmed that the effects of the present invention were sufficiently achieved by a simple and low-cost configuration in which the rubbing body was provided at a predetermined position.

It is a perspective view showing one embodiment of a wire saw device concerning the present invention. It is a figure which shows the cutting state of the wire saw apparatus concerning this invention. It is a perspective view which shows another embodiment of the wire saw apparatus concerning this invention. It is a perspective view which shows another embodiment of the wire saw apparatus concerning this invention. It is a perspective view which shows another embodiment of the wire saw apparatus concerning this invention. It is a perspective view of the conventional wire saw apparatus.

Explanation of symbols

1: Slurry nozzle 2: Slurry receptacle 3: Silicon ingot 4: Slice base 5: Main roller 6: Wire 6a: Brass plating layer 7: End material entrainment prevention plate 8: Dip tank 9: Wire supply reel 10: Glass plate (slider) Rubbing)

Claims (5)

It is a wire saw device that forms a semiconductor substrate by cutting a semiconductor ingot by moving a wire of a metal wire having a plating layer on the surface at high speed and pressing it against the semiconductor ingot while supplying abrasive slurry. The wire saw device is provided with a rubbing body that rubs against the wire and removes the plating layer before the point where the wire and the semiconductor ingot are in contact with each other on the path of the wire. . The wire saw device according to claim 1, wherein the wire is a metal wire mainly composed of iron or an iron alloy, and the plated layer is a brass plated layer mainly composed of copper and zinc. The wire saw device according to claim 1 or 2, wherein the wire is configured to cut the rubbing body simultaneously with cutting the semiconductor ingot. The wire saw device according to claim 3, wherein the rubbing body is fixed in contact with the semiconductor ingot. The wire saw device according to any one of claims 1 to 4, wherein the rubbing body is mainly composed of glass.

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