A method for cutting a single crystal silicon wafer

Abstract

This invention relates to a method for cutting monocrystalline silicon wafers, which can effectively address the diamond wire skipping and breakage phenomena that occur during the cutting process. The method includes the following steps: changing the shape of the cutting roller, setting a limiting pressure plate, increasing the cutting tension, adding a filter cylinder inside the slurry pipe, and using slurry to flush the cutting roller while simultaneously reducing the cutting speed. In use, this method reduces the likelihood of foreign objects getting stuck by changing the shape of the cutting roller, restricts the position of the diamond wire during cutting by using the limiting pressure plate, ensures a tight fit between the diamond wire and the cutting roller by increasing the cutting tension, enhances the filtration effect of the slurry by adding a filter cylinder inside the slurry pipe, and uses the filtered slurry to flush the cutting roller to ensure no foreign objects get stuck. Simultaneously, reducing the cutting speed during flushing expands the flushing window of the cutting roller, enhancing the flushing effect and reducing the probability of diamond wire skipping and breakage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor material cutting, in particular to a single crystal silicon wafer cutting processing method. BACKGROUND

[0002] The single crystal silicon wafer is a kind of thin and brittle semiconductor material, which is widely used in integrated circuits, solar cells, optoelectronic devices and other fields, and it is one of important materials in modern electronic industry, which has excellent electronic characteristics and semiconductor properties. In the production of single crystal silicon wafer, the crystal silicon rod needs to be cut into thin slices by the diamond wire slicing machine to obtain single crystal silicon wafer with appropriate size and thickness.

[0003] In the cutting of the crystal silicon rod, the crystal silicon rod is fixed on the lower surface of the lifting workbench of the diamond wire slicing machine by fixing the workpiece, and as the workbench descends, the mortar pipe assembled on the device sprays mortar to the cutting position between the diamond wire and the crystal silicon rod under the action of the pressure pump, the mortar is driven by the diamond wire to move back and forth at high speed, and the diamond particles on the diamond wire cut the crystal silicon rod to cut the crystal silicon rod into multiple single crystal silicon wafers at one time.

[0004] The existing diamond wire slicing machine has the problem that the flying silicon powder and other impurities in the cutting process adhere to the cutting roller, which causes the diamond wire to jump or break during the cutting process, directly affecting the cutting yield, and causing process problems such as single crystal silicon wafer fragments, wire marks, color difference, uneven thickness, and low product yield. Therefore, the technical personnel in the field provide a single crystal silicon wafer cutting processing method to solve the problems in the background art. SUMMARY

[0005] In order to solve the problem that the flying silicon powder and other impurities in the cutting process adhere to the cutting roller, which causes the diamond wire to jump or break during the cutting process, the present application provides a single crystal silicon wafer cutting processing method.

[0006] The single crystal silicon wafer cutting processing method provided by the present application adopts the following technical scheme:

[0007] A single crystal silicon wafer cutting processing method for cutting a crystal silicon rod into a single crystal silicon wafer on a diamond wire slicing machine, the single crystal silicon wafer cutting processing method comprising the following steps:

[0008] A, the crystal silicon rod is fixed on the lower surface of the lifting workbench of the diamond wire slicing machine by a fixed workpiece, the diamond wire is spirally wound on the cutting rollers arranged on the opposite sides of the workbench and the small rollers located inside the workbench, and the diamond wire mesh is arranged below the crystal silicon rod; a plurality of grooves are uniformly arranged on the cutting roller, the diamond wire is located in the grooves, and the grooves are connected by stem portions; a limiting pressing plate is arranged on the lower surface of the mortar pipe of the workbench, the position of the mortar pipe is adjusted so that the limiting pressing plate is in contact with or has a small gap with the cutting roller, and the diamond wire is limited in the grooves by the limiting pressing plate;

[0009] B, as the crystal silicon rod descends, the mortar pipe sprays mortar to the cutting position between the diamond wire and the crystal silicon rod under the action of the pressure pump, the mortar is reciprocatingly and high-velocity moved by the diamond wire, the diamond particles on the diamond wire cut the crystal silicon rod, and the crystal silicon rod is cut into a plurality of single crystal silicon wafers at one time; two filter barrels are arranged in the mortar pipe, the mortar is filtered by the filter barrels, and the filtered mortar is used to flush the cutting roller in the cutting process; and the top of the diamond wire slicing machine is fixedly connected with an automatic spraying pipeline.

[0010] Preferably, the depth of the groove of the cutting roller is 0.193-0.200 mm, and the angle of the groove is 24°-28°.

[0011] Preferably, the stem portion of the cutting roller is 0.07-0.1 mm.

[0012] By adopting the above technical scheme, reducing the depth of the groove can reduce the probability of foreign matter entering the groove, and enlarging the stem portion can increase the probability of foreign matter directly falling on the stem portion and reduce the probability of foreign matter entering the groove.

[0013] Preferably, the stem portion of the cutting roller is 0.07-0.1 mm.

[0014] By adopting the above technical scheme, the small groove can prevent the diamond wire from jumping into the adjacent groove, thereby preventing the wire from jumping and reducing the related loss of the wire.

[0015] Preferably, the cutting tension of the diamond wire is 3.0-4.2 N.

[0016] By adopting the above technical scheme, the cutting tension is improved, the engagement between the diamond wire and the cutting roller is ensured to be tight and close, and the purpose of preventing the wire from jumping is achieved.

[0017] Preferably, the filter bag in the filter barrel is greater than 80 mesh.

[0018] By adopting the technical scheme, the filtering effect on the foreign matters in the mortar is enhanced by increasing the number of the filtering barrels, and the filtering effect is improved by increasing the mesh number of the filtering bag, so that the mortar is kept clean and free of foreign matters.

[0019] Preferably, when the diamond wire cuts the crystal silicon rod, the cutting wire speed is 1500-2400 m / min.

[0020] By adopting the technical scheme, the rotation speed of the cutting roller is reduced by reducing the cutting wire speed, so that the washing window of the cutting roller is enlarged, the washing time of the cutting roller is prolonged, and the cutting groove of the cutting roller is kept free of foreign matters.

[0021] In summary, the present application has the following beneficial technical effects:

[0022] 1. In the present application, the probability of foreign matters entering the cutting groove is reduced by reducing the cutting groove depth after changing the shape of the cutting roller. When the cutting groove depth is reduced, the groove stem part of the cutting roller is enlarged. When foreign matters fall on the cutting roller, the probability of the foreign matters directly falling on the groove stem part is increased by the enlarged groove stem, and the probability of the foreign matters entering the cutting groove is reduced. Small grooves are arranged on the groove stem to prevent the diamond wire from jumping into the adjacent cutting groove. The engagement between the diamond wire and the cutting roller is ensured to be tight and close by increasing the cutting tension, so that the purpose of preventing the diamond wire from jumping is achieved.

[0023] 2. In the present application, the filtering effect on the foreign matters in the mortar is enhanced by the two filtering barrels arranged in the mortar pipe, and the mesh number of the filtering bag in the filtering barrel is increased to improve the filtering effect and keep the mortar clean and free of foreign matters. The rotation speed of the cutting roller is reduced by reducing the cutting wire speed, so that the washing window of the cutting roller is enlarged, the washing time of the cutting roller is prolonged, and the cutting groove of the cutting roller is kept free of foreign matters, so that the purpose of reducing the diamond wire jumping rate is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0024] Fig. 1 is a front view structural schematic diagram of a diamond wire slicing machine according to an embodiment of the present application;

[0025] Fig. 2 is a microsection structural schematic diagram of the cutting roller in the length direction according to the present application;

[0026] Fig. 3 is a microsection structural schematic diagram of the cutting roller in the length direction according to another embodiment of the present application.

[0027] Mark 1, cutting roller; 101, cutting groove; 102, groove stem; 2, diamond wire; 3, small groove; 4, mortar pipe; 5, limiting pressing plate; 6, automatic spraying pipeline; 7, small roller. DETAILED DESCRIPTION

[0028] The application is further described below in conjunction with the accompanying drawings. Figs. 1-3 The application is further described below in conjunction with the accompanying drawings.

[0029] The application discloses a single crystal silicon wafer cutting processing method. The single crystal silicon wafer cutting processing method is formulated for the wire jump and breakage of the diamond wire 2 in the process of the approach cutting operation, and corresponding processing measures are formulated.

[0030] A, the crystal silicon rod is fixed on the lower surface of the lifting workbench of the diamond wire slicing machine, the diamond wire slicing machine mainly comprises a rack, a workbench for fixing the workpiece and capable of lifting operation, a small roller for guiding the diamond wire 2, and two cutting rollers 1 arranged on the opposite sides of the workbench, and the like, in the actual cutting process of the crystal silicon rod, the single wire length of 240km of the diamond wire 2 is spirally wound on the two cutting rollers 1 arranged on the opposite sides of the workbench and the small roller 7 located in the workbench, so that the diamond wire 2 forms a cutting wire net on the two cutting rollers 1 arranged on the opposite sides of the workbench, and the diamond wire net is arranged below the crystal silicon rod;

[0031] B, with the descent of the crystal silicon rod, the mortar pipe 4 assembled on the equipment sprays the mortar to the cutting position between the diamond wire 2 and the crystal silicon rod under the action of the pressure pump, the mortar can cool and lubricate the cutting position, and can also flush away the impurities during cutting, so as to prevent the impurities from adhering and reduce the quality problems during cutting, the mortar is driven by the diamond wire 2 to move back and forth at high speed, the diamond particles on the diamond wire 2 cut the crystal silicon rod, so as to cut the crystal silicon rod into multiple single crystal silicon wafers at one time, compared with the traditional knife saw blade, the grinding wheel and the internal circle cutting, the multi-wire cutting technology has the advantages of high efficiency, high productivity and high precision.

[0032] In order to avoid the wire jump and breakage of the diamond wire 2, the application takes the following measures for this situation: (1) changing the shape of the cutting roller 1 to reduce the probability of foreign matter being stuck in the cutting roller 1, (2) setting the limiting pressure plate 5 to limit the wire jump of the diamond wire 2, and (3) improving the cutting tension to ensure the tightness and closeness of the engagement between the diamond wire 2 and the cutting roller 1.

[0033] Further, in order to avoid foreign matter in the cutting roller 1, the present application takes measures for this situation, that is, two filtering barrels are arranged in the mortar pipe 4, double-barrel filtered mortar is used, the filtering effect of foreign matter in the mortar is enhanced by increasing the number of filtering barrels, and the filtered mortar is used to flush the cutting roller 1, the function of flushing the cutting roller 1 by mortar in the cutting process is introduced on the basis of manual spraying and flushing the cutting chamber after the original slicing, the flushing of the cutting roller 1 is superimposed by the high-speed rotation of the cutting roller 1 in the cutting process, the cleanliness of the cutting roller 1 is ensured, the probability of wire jump and wire break is reduced, the flushing window of the cutting roller 1 is expanded by reducing the cutting line speed, and the flushing effect of the cutting roller 1 is enhanced.

[0034] In the embodiment, foreign matter generated during cutting may enter the inside of the cutting roller 1 during use, which may affect the transmission of the diamond wire 2 by the cutting roller 1. When foreign matter enters the inside of the cutting roller 1, the diamond wire 2 may jump or break, which may affect the yield of the single crystal silicon wafer cutting production. Therefore, the shape of the cutting roller 1 needs to be improved to reduce the probability of foreign matter entering the inside of the cutting roller 1 and reduce the probability of wire jump or wire break. Two filtering barrels are arranged in the mortar pipe 4 to enhance the filtering effect of foreign matter in the mortar and reduce the occurrence of foreign matter in the cutting area. The mortar is used to flush the cutting roller 1 to clean the cutting roller 1 in time when foreign matter enters the inside of the cutting roller 1, which can enhance the probability of preventing wire jump and wire break of the diamond wire 2, prolong the service life of the diamond wire 2, and improve the yield of the single crystal silicon wafer cutting process.

[0035] In the further preferred embodiment of the present application, a plurality of grooves 101 are uniformly arranged on the cutting roller 1, and the diamond wire 2 is located in the grooves 101. The plurality of grooves 101 can limit the installation position of the diamond wire 2, and the rotation of the two cutting rollers 1 can drive the diamond wire 2 to move and cut. The adjacent grooves 101 are separated by a groove stem 102.

[0036] Further, the depth of the groove 101 of the cutting roller 1 is 0.193-0.200 mm, and the preferred value is 0.193 mm. The angle of the groove 101 is 24°-28°, and the preferred value is 28°. Therefore, the probability of foreign matter entering the inside of the groove 101 is reduced. The range of the groove stem 102 of the cutting roller 1 is 0.07-0.1 mm, and the preferred value is 0.088 mm. When foreign matter falls on the cutting roller 1, the probability of the foreign matter directly falling on the groove stem 102 is increased due to the expansion of the groove stem 102, and the probability of the foreign matter entering the inside of the groove 101 is reduced.

[0037] Further, the groove 3 is opened on the groove stem 102 part of the cutting roller 1, the depth of the groove 3 is 0.02-0.03mm, preferably 0.026mm, the opened groove 3 does not participate in production, and the main function is to prevent the diamond wire 2 from jumping into the adjacent groove 101, affecting the use of the diamond wire 2 in the adjacent groove 101, so that the design of the groove 3 can prevent the wire from jumping and reduce the related loss of the wire.

[0038] In the embodiment, the several grooves 101 and the several groove stems 102 are arranged at intervals, the position of the installation and transmission of the diamond wire 2 is limited by the opened groove 101, and the groove 101 is a concave groove, so that when foreign matter splashes, the foreign matter may fall into the inside of the groove 101, when there is foreign matter in the groove 101, in the process of conveying the diamond wire 2, the foreign matter may cause the diamond wire 2 to be pulled out of the groove 101, or cause the diamond wire 2 to directly break, and the diamond wire 2 may also jump into the adjacent groove 101, when the diamond wire 2 jumps into the adjacent groove 101, it may affect the use of the diamond wire 2 in the adjacent groove 101, thereby reducing the yield of the single crystal silicon wafer cutting; further, by reducing the depth of the groove 101 of the cutting roller 1 and expanding the groove stem 102 of the cutting roller 1, the probability of the foreign matter directly entering the inside of the groove 101 can be reduced, thereby the probability of the diamond wire 2 jumping and breaking can be reduced, further, by opening the groove 3 on the groove stem 102, the diamond wire 2 can be prevented from jumping into the adjacent groove 101, thereby the loss caused by the diamond wire 2 jumping can be reduced as much as possible.

[0039] In the further preferred embodiment of the present application, the cutting tension of the diamond wire 2 is 3.0-4.2N, preferably 3.9N, which can ensure the tightness of the engagement between the diamond wire 2 and the cutting roller 1, thereby achieving the purpose of preventing the diamond wire 2 from jumping.

[0040] In further preferable embodiments of the present application, the lower surface of the mortar pipe 4 is provided with a limiting pressing plate 5, the limiting pressing plate 5 has a width greater than the length of the cutting roller 1, the limiting pressing plate 5 is in contact with or has a small gap with the cutting roller 1, the position of the diamond wire 2 on the cutting roller 1 can be limited by the limiting pressing plate 5, so as to enhance the anti-wire-jumping effect of the cutting roller 1, two filtering barrels are arranged in the mortar pipe 4, the mortar is filtered by the filtering barrels, the filtering effect of the foreign matters in the mortar is enhanced by increasing the number of the filtering barrels, further, the filtering bag in the filtering barrel has a mesh size greater than 80, preferably 150, the filtering effect is improved, the filtering bag can be cleaned and reused, the foreign matters in the mortar are prevented as much as possible, and the energy saving and environmental protection effect is achieved, the top of the diamond wire slicing machine is fixedly connected with an automatic spraying pipeline 6, the working area can be sprayed and washed by starting the automatic spraying pipeline 6 after the cutting is completed.

[0041] In further preferable embodiments of the present application, when the diamond wire 2 cuts the crystal silicon rod, the cutting line speed ranges from 1500 m / min to 2400 m / min, and the preferred value is 2000 m / min, the rotating speed of the cutting roller 1 can be reduced, so as to enlarge the washing window of the cutting roller 1, prolong the washing time of the mortar on the cutting roller 1 as much as possible, ensure that there is no foreign matter in the slotting 101 of the cutting roller 1, and achieve the purpose of reducing the wire-jumping rate of the diamond wire 2.

[0042] The implementation principle of the single crystal silicon wafer cutting processing method of the embodiments of the present application is as follows:

[0043] In use, the shape of the cutting roller 1 is changed to reduce the probability of foreign matters being stuck in the cutting roller 1, and the limiting pressing plate 5 is arranged to limit the wire-jumping of the diamond wire 2, the cutting tension is increased to ensure the tightness between the diamond wire 2 and the cutting roller 1, two filtering barrels are arranged in the mortar pipe 4 to enhance the filtering effect of the foreign matters in the mortar, the cutting roller 1 is washed by the filtered mortar to ensure the cleanliness of the surface of the cutting roller 1 and prevent foreign matters from being stuck in the cutting roller 1, the washing window of the cutting roller 1 is enlarged by reducing the cutting line speed to enhance the washing effect of the cutting roller 1, the probability of wire-jumping and wire-breaking of the diamond wire 2 is reduced, and the present application is more convenient for actual use.

[0044] The above are preferable embodiments of the present application, but do not limit the protection scope of the present application, therefore: any equivalent changes made according to the structure, shape and principle of the present application should be covered in the protection scope of the present application.

Claims

1. A method for cutting and processing single-crystal silicon wafers, characterized in that, The method for cutting a single crystal silicon wafer from a single crystal silicon rod on a diamond wire sawing machine comprises the following steps: A. The single crystal silicon rod is fixed on the lower surface of the lifting workbench of the diamond wire sawing machine by a fixed workpiece, and the diamond wire (2) is wound in a spiral shape on the cutting roller (1) and the small roller (7) located inside the workbench, so that the diamond wire (2) is arranged below the single crystal silicon rod; a plurality of grooves (101) are uniformly formed on the cutting roller (1), and the diamond wire (2) is located inside the grooves (101), and the grooves (101) are connected by the stem (102); the stem (102) of the cutting roller (1) is provided with a small groove (3), and the depth of the small groove (3) is 0.02-0.03mm; the lower surface of the mortar pipe (4) of the workbench is provided with a limiting pressing plate (5), and the position of the mortar pipe (4) is adjusted so that the limiting pressing plate (5) is in contact with or has a small gap with the cutting roller (1), and the diamond wire (2) is limited in the grooves (101) by the limiting pressing plate (5); B. As the single crystal silicon rod descends, the mortar pipe (4) sprays mortar to the cutting position between the diamond wire (2) and the single crystal silicon rod under the action of the pressure pump, and the mortar is driven by the diamond wire (2) to move back and forth at high speed, and the diamond particles on the diamond wire (2) cut the single crystal silicon rod to cut the single crystal silicon rod into multiple single crystal silicon wafers at one time; two filter barrels are arranged in the mortar pipe (4), the mortar is filtered by the filter barrels, and the filtered mortar is used to flush the cutting roller (1) during the cutting process, and the top of the diamond wire sawing machine is fixedly connected with an automatic spraying pipeline (6).

2. The method of claim 1 wherein: The depth of the groove (101) of the cutting roller (1) is 0.193-0.200mm, and the angle of the groove (101) is 24°-28°.

3. The method of claim 1 wherein: The stem (102) of the cutting roller (1) is 0.07-0.1mm. ​ 4. The method of claim 1 wherein: The cutting tension of the diamond wire (2) is 3.0-4.2N. ​ 5. The method of claim 1 wherein: The filter barrel is provided with a filter bag, and the filter bag is greater than 80 mesh. ​ 6. The method of claim 1 wherein: When the diamond wire (2) cuts the single crystal silicon rod, the cutting line speed is 1500-2400m / min.

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