A process for re-cutting 8-inch semiconductor silicon crystal rods after diamond wire cutting and wire breakage

Abstract

A re-cutting process after a broken wire is cut by diamond wire cutting of an 8-inch semiconductor silicon crystal rod. First, the diamond wire net after the wire break is connected, and the crystal rod is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap. After the diamond wire is located at the broken position, the crystal rod is controlled to stop moving, and then the crystal rod is transition-cut. After the transition-cutting is completed, the uncut part of the crystal rod is cut again using the cutting process before the wire break. During the transition-cutting, the linear speed of the diamond wire is 90m / min-100m / min, and the cutting liquid is sprayed toward the broken position of the silicon wafer, and its flow rate is 88L / min-92L / min, so that the cutting liquid can soak the diamond wire and be brought into the silicon wafer gap during the cutting process. The transition-cutting is ended when the wire feed amount of the diamond wire is 6m. The silicon wafer surface obtained by the present invention has no steps and line marks, which solves the problem of defects after the crystal rod is re-cut.

Description

Technical Field

[0001] The present invention relates to the technical field of diamond wire cutting, and in particular to a process for re-cutting an 8-inch semiconductor silicon crystal rod after a wire breakage caused by diamond wire cutting. Background Art

[0002] During the diamond wire sawing process of an 8-inch semiconductor silicon ingot, the wire is prone to breakage due to its small diameter and high wire speed. After a break, the 8-inch semiconductor silicon ingot, including the silicon wafers formed by the diamond wire and the uncut portion, needs to be lifted to reposition the diamond wire. Then, the 8-inch semiconductor silicon ingot needs to be pressed down to allow the diamond wire to enter the gap between two adjacent silicon wafers for re-slicing. However, because the gap between two adjacent silicon wafers is larger than the diamond wire diameter, after re-slicing, defects such as steps and line marks are likely to appear at the break point of the silicon wafer, even rendering the wafer scrapped. Summary of the Invention

[0003] In order to solve the problem of defects occurring after re-cutting of crystal rods in the prior art, the present invention provides a re-cutting process for 8-inch semiconductor silicon crystal rods after diamond wire cutting breaks, with no steps or line marks on the silicon wafer surface, fundamentally solving the problem of defects occurring after re-cutting of crystal rods.

[0004] In order to achieve the above-mentioned purpose, the specific scheme adopted by the present invention is: a re-cutting process for an 8-inch semiconductor silicon crystal rod after diamond wire cutting and breakage, first, the diamond wire mesh after the break is connected, and the crystal rod is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is located at the break position and the crystal rod is controlled to stop moving, and then the crystal rod is transition cut. After the transition cutting is completed, the uncut part of the crystal rod is cut again using the cutting process before the break; during the transition cutting, the wire speed of the diamond wire is 90m / min-100m / min, and the cutting liquid is sprayed toward the break position of the silicon wafer, and its flow rate is 88L / min-92L / min, so that the cutting liquid can soak the diamond wire and can bring the cutting liquid into the silicon wafer gap during the cutting process; the transition cutting is ended when the wire feed amount of the diamond wire is 6m.

[0005] This is a further optimization of the re-cutting process after the diamond wire cutting of an 8-inch semiconductor silicon crystal rod of the present invention is broken: the crystal rod moves toward the diamond wire at a feed speed of 14mm / min-16mm / min.

[0006] This is a further optimization of the re-cutting process after the diamond wire cutting of an 8-inch semiconductor silicon crystal rod of the present invention is broken: the crystal rod moves toward the diamond wire at a feed speed of 15mm / min.

[0007] This is a further optimization of the re-cutting process after the diamond wire cutting of an 8-inch semiconductor silicon crystal rod of the present invention is broken: when the crystal rod moves toward the diamond wire, cutting fluid is sprayed into the gap of the silicon wafer, the flow rate of the cutting fluid is 88L / min-92L / min, and the temperature of the cutting fluid is 20℃-22℃.

[0008] This is a further optimization of the re-cutting process after the diamond wire cutting of an 8-inch semiconductor silicon crystal rod of the present invention is broken: in the transition cutting, the wire speed of the diamond wire is 93m / min-98m / min.

[0009] This is a further optimization of the re-cutting process after the diamond wire cutting of an 8-inch semiconductor silicon crystal rod is broken in the present invention: during the transition cutting, the flow rate of the cutting fluid is 90L / min.

[0010] This is a further optimization of the re-cutting process after the diamond wire cutting of an 8-inch semiconductor silicon crystal rod of the present invention is broken: in the cutting process before the wire is broken, the crystal rod is cut at a feed speed of 0.6mm / min-1.0mm / min.

[0011] This is a further optimization of the re-cutting process after the diamond wire cutting of an 8-inch semiconductor silicon crystal rod of the present invention is broken: in the cutting process before the wire is broken, the diamond wire cuts the crystal rod at a linear speed of 1200m / min-1800m / min.

[0012] This is a further optimization of the re-cutting process after the diamond wire cutting of an 8-inch semiconductor silicon crystal rod is broken in the present invention: in the cutting process before the wire is broken, the flow rate of the cutting fluid is 88L / min-92L / min during the process of the diamond wire cutting the uncut part of the crystal rod. After the cutting fluid flows through the overflow pipe to the diamond wire mesh, the cutting fluid is soaked in the diamond wire and can be brought into the gaps of the silicon wafer during the cutting process. The temperature of the cutting fluid is 20℃-22℃.

[0013] Beneficial effects:

[0014] 1. The present invention provides a re-cutting process for 8-inch semiconductor silicon ingots after a wire break during diamond wire cutting. The process is applicable only to 8-inch semiconductor silicon ingots. The rearranged diamond wire moves into the interior of the ingot until it reaches the break position. The ingot stops moving and the diamond wire performs a transition cut at the break position. The uncut portion of the ingot is then cut, thus avoiding defects such as steps or line marks on the surface of the cut silicon wafers.

[0015] 2. In S1 of the present invention, during the movement of the crystal rod toward the diamond wire, lubricant is sprayed inside the crystal rod and at the position of the diamond wire to facilitate the movement of the diamond wire inside the crystal rod. DETAILED DESCRIPTION

[0016] Example 1

[0017] A process for re-cutting an 8-inch semiconductor silicon ingot after a broken diamond wire is cut comprises the following steps:

[0018] 1) Reconnect the broken diamond wire mesh and control the crystal ingot to move toward the diamond wire at a feed rate of 14mm / min, so that the diamond wire enters the corresponding silicon wafer gap. The crystal ingot stops moving after the diamond wire is at the break point. During the movement of the crystal ingot, spray cutting fluid into the silicon wafer gap at a flow rate of 92L / min and a temperature of 20°C.

[0019] 2) Perform transition cutting on the crystal rod. During transition cutting, the linear speed of the diamond wire is 90m / min, and the cutting liquid is sprayed toward the wire break position of the silicon wafer with a flow rate of 92L / min, so that the cutting liquid can soak the diamond wire and be brought into the gap of the silicon wafer during the cutting process. The transition cutting is completed when the wire feed amount of the diamond wire is 6m.

[0020] 3) After the transition cut is complete, the uncut portion of the ingot is cut again using the same cutting process as before wire breaking. The cutting process parameters before wire breaking are: ingot feed speed of 0.9 mm / min, diamond wire speed of 1500 m / min, cutting fluid flow rate of 92 L / min, cutting fluid flowing through an overflow pipe onto the diamond wire mesh, soaking the diamond wire and allowing the cutting fluid to penetrate the gaps between the silicon wafers during the cutting process. The cutting fluid temperature is 20°C.

[0021] After testing, the surface of the cut silicon wafer has no wire marks or steps, and the warping is 1μm larger than that of the silicon wafer obtained by continuous wire cutting.

[0022] The above is a basic implementation of the present invention, and further improvements, optimizations and limitations can be made on the above basis to obtain the following embodiments:

[0023] Example 2

[0024] 1) Reconnect the broken diamond wire mesh and control the crystal ingot to move toward the diamond wire at a feed rate of 14mm / min, so that the diamond wire enters the corresponding silicon wafer gap. The crystal ingot is controlled to stop moving after the diamond wire is at the break point. During the movement of the crystal ingot, the cutting fluid is sprayed into the silicon wafer gap at a flow rate of 90L / min and a temperature of 20°C.

[0025] 2) Perform transition cutting on the crystal rod. During transition cutting, the wire speed of the diamond wire is 95m / min, and the cutting liquid is sprayed toward the wire break position of the silicon wafer with a flow rate of 90L / min, so that the cutting liquid can soak the diamond wire and be brought into the gap of the silicon wafer during the cutting process. The transition cutting is completed when the wire feed amount of the diamond wire is 6m.

[0026] 3) After the transition cut is complete, the uncut portion of the ingot is cut again using the same cutting process as before wire breaking. The cutting process parameters before wire breaking are: ingot feed speed of 0.9 mm / min, diamond wire speed of 1500 m / min, cutting fluid flow rate of 90 L / min, cutting fluid flowing through an overflow pipe onto the diamond wire mesh, soaking the diamond wire and allowing the cutting fluid to penetrate the gaps between the silicon wafers during the cutting process. The cutting fluid temperature is 20°C.

[0027] After testing, it was found that the surface of the silicon wafer obtained by cutting had no wire marks or steps, and the warping was the same as that of the silicon wafer obtained by continuous wire cutting.

[0028] Example 3

[0029] 1) Reconnect the broken diamond wire mesh and control the crystal ingot to move toward the diamond wire at a feed rate of 14mm / min, so that the diamond wire enters the corresponding silicon wafer gap. The crystal ingot is controlled to stop moving after the diamond wire is at the break point. During the movement of the crystal ingot, the cutting fluid is sprayed into the silicon wafer gap at a flow rate of 90L / min and a temperature of 20°C.

[0030] 2) Perform transition cutting on the crystal rod. During transition cutting, the linear speed of the diamond wire is 98m / min, and the cutting liquid is sprayed toward the wire break position of the silicon wafer with a flow rate of 90L / min, so that the cutting liquid can soak the diamond wire and be brought into the gap of the silicon wafer during the cutting process. The transition cutting is completed when the wire feed amount of the diamond wire is 6m.

[0031] 3) After the transition cut is complete, the uncut portion of the ingot is cut again using the same cutting process as before wire breaking. The cutting process parameters before wire breaking are: ingot feed speed of 0.9 mm / min, diamond wire speed of 1500 m / min, cutting fluid flow rate of 90 L / min, cutting fluid flowing through an overflow pipe onto the diamond wire mesh, soaking the diamond wire and allowing the cutting fluid to penetrate the gaps between the silicon wafers during the cutting process. The cutting fluid temperature is 20°C.

[0032] After testing, the surface of the cut silicon wafer has no wire marks or steps, and the warping is 1μm larger than that of the silicon wafer obtained by continuous wire cutting.

[0033] Example 4

[0034] 1) Reconnect the broken diamond wire mesh and control the crystal ingot to move toward the diamond wire at a feed rate of 14mm / min, so that the diamond wire enters the corresponding silicon wafer gap. The crystal ingot is controlled to stop moving after the diamond wire is at the break point. During the movement of the crystal ingot, the cutting fluid is sprayed into the silicon wafer gap at a flow rate of 88L / min and a temperature of 20°C.

[0035] 2) Perform transition cutting on the crystal rod. During transition cutting, the wire speed of the diamond wire is 100m / min, and the cutting liquid is sprayed toward the wire break position of the silicon wafer with a flow rate of 88L / min, so that the cutting liquid can soak the diamond wire and be brought into the gap of the silicon wafer during the cutting process. The transition cutting is completed when the wire feed amount of the diamond wire is 6m.

[0036] 3) After the transition cut is complete, the uncut portion of the ingot is cut again using the same cutting process as before wire breakage. The cutting process parameters before wire breakage are: ingot feed speed of 0.9 mm / min, diamond wire speed of 1500 m / min, cutting fluid flow rate of 88 L / min, with the cutting fluid flowing through an overflow pipe onto the diamond wire mesh. The cutting fluid soaks the diamond wire and is carried into the gaps between the silicon wafers during the cutting process. The cutting fluid temperature is 20°C.

[0037] After testing, the surface of the cut silicon wafer has no wire marks or steps, and the warping is 2μm larger than that of the silicon wafer obtained by continuous wire cutting.

[0038] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0039] In order to verify the advantages of the present invention over the prior art, the following comparative experiments were conducted:

[0040] Experimental example

[0041] The re-cutting process after wire breaking in this experimental example is the same as that in Example 3. The surface of the silicon wafer obtained by cutting has no wire marks or steps, and the warpage is 1 μm larger than that of the silicon wafer obtained by cutting without wire breaking.

[0042] Comparative Example 1

[0043] A process for re-cutting an 8-inch semiconductor silicon crystal ingot after a wire break during diamond wire cutting. First, the diamond wire mesh after the break is connected, and the crystal ingot is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is at the break position. Then, the uncut portion of the crystal ingot is cut again using the cutting process before the break. In this comparative example, the process parameters of the process of moving the crystal ingot toward the diamond wire and the cutting process before the break are the same as those in Example 3.

[0044] After testing, it was found that there were slight steps on the surface of the cut silicon wafer, and the warping was 13μm larger than that of the silicon wafer obtained by continuous wire cutting.

[0045] Comparative Example 2

[0046] A process for re-cutting an 8-inch semiconductor silicon crystal rod after a wire break by diamond wire cutting. First, the diamond wire mesh after the break is connected, and the crystal rod is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is at the break position and stops moving. Then, the diamond wire is transitionally cut at a wire speed of 8m / min and a wire feed of 2m. During the cutting process, the cutting liquid is sprayed toward the break position of the silicon wafer, and its flow rate is 92L / min. The temperature of the cutting liquid is 20°C. Finally, the uncut part of the crystal rod is cut again using the cutting process before the break. In this comparative example, the process parameters of the crystal rod moving toward the diamond wire and the cutting process before the break are the same as those in Example 3.

[0047] After testing, it was found that there were slight steps on the surface of the cut silicon wafer, and the warping was 12μm larger than that of the silicon wafer obtained by continuous cutting.

[0048] Comparative Example 3

[0049] A process for re-cutting an 8-inch semiconductor silicon crystal rod after a wire break by diamond wire cutting. First, the diamond wire mesh after the break is connected, and the crystal rod is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is at the break position and stops moving. Then, the diamond wire is transitionally cut at a wire speed of 45m / min and a wire feed of 4m. During the cutting process, the cutting liquid is sprayed toward the break position of the silicon wafer, and its flow rate is 92L / min. The temperature of the cutting liquid is 20°C. Finally, the uncut part of the crystal rod is cut again using the cutting process before the break. In this comparative example, the process parameters of the crystal rod moving toward the diamond wire and the cutting process before the break are the same as those in Example 3.

[0050] After testing, it was found that there were slight steps on the surface of the cut silicon wafer, and the warping was 12μm larger than that of the silicon wafer obtained by continuous cutting.

[0051] Comparative Example 4

[0052] A process for re-cutting an 8-inch semiconductor silicon crystal rod after a wire break during diamond wire cutting. First, the diamond wire mesh after the break is connected, and the crystal rod is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is at the break position and stops moving. Then, the diamond wire is transitionally cut at a wire speed of 200m / min and a wire feed of 8m. During the cutting process, the cutting liquid is sprayed toward the break position of the silicon wafer, and its flow rate is 88L / min. The temperature of the cutting liquid is 20°C. Finally, the uncut part of the crystal rod is cut again using the cutting process before the break. In this comparative example, the process parameters of the crystal rod moving toward the diamond wire and the cutting process before the break are the same as those in Example 3.

[0053] After testing, it was found that deep lines appeared on the surface of the cut silicon wafer, causing the entire crystal rod to be scrapped.

[0054] Comparative Example 5

[0055] A process for re-cutting an 8-inch semiconductor silicon crystal ingot after a wire break during diamond wire cutting. First, the diamond wire mesh after the wire break is connected, and the crystal ingot is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap. The movement is stopped after the diamond wire is 1 mm above the wire break position. Then, the uncut portion of the crystal ingot is cut again using the cutting process before the wire break. In this comparative example, the process parameters of the process of moving the crystal ingot toward the diamond wire and the cutting process before the wire break are the same as those in Example 3.

[0056] After testing, it was found that serious steps appeared on the surface of the cut silicon wafer, and the entire crystal rod was scrapped.

[0057] Comparative Example 6

[0058] A process for re-cutting an 8-inch semiconductor silicon crystal rod after a wire break by diamond wire cutting. First, the diamond wire mesh after the break is connected, and the crystal rod is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is 1 mm above the break position and stops moving. Then, the diamond wire is transitionally cut at a wire speed of 8 m / min and a wire feed of 2 m. During the cutting process, the cutting liquid is sprayed toward the break position of the silicon wafer, and its flow rate is 92 L / min. The temperature of the cutting liquid is 20°C. Finally, the uncut part of the crystal rod is cut again using the cutting process before the break. In this comparative example, the process parameters of the crystal rod moving toward the diamond wire and the cutting process before the break are the same as those in Example 3.

[0059] After testing, it was found that serious steps appeared on the surface of the cut silicon wafer, causing the entire crystal rod to be scrapped.

[0060] Comparative Example 7

[0061] A process for re-cutting an 8-inch semiconductor silicon crystal rod after a wire break by diamond wire cutting. First, the diamond wire mesh after the break is connected, and the crystal rod is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is 1 mm above the break position and stops moving. Then, the diamond wire is transitionally cut at a wire speed of 45 m / min and a wire feed of 4 m. During the cutting process, the cutting liquid is sprayed toward the break position of the silicon wafer, and its flow rate is 92 L / min. The temperature of the cutting liquid is 20°C. Finally, the uncut part of the crystal rod is cut again using the cutting process before the break. In this comparative example, the process parameters of the crystal rod moving toward the diamond wire and the cutting process before the break are the same as those in Example 3.

[0062] After testing, it was found that serious steps appeared on the surface of the cut silicon wafer, causing the entire crystal rod to be scrapped.

[0063] Comparative Example 8

[0064] A process for re-cutting an 8-inch semiconductor silicon crystal rod after a wire break by diamond wire cutting. First, the diamond wire mesh after the break is connected, and the crystal rod is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is 1 mm above the break position and stops moving. Then, the diamond wire is transitionally cut at a wire speed of 98 m / min and a wire feed of 6 m. During the cutting process, the cutting liquid is sprayed toward the break position of the silicon wafer, and its flow rate is 90 L / min. The temperature of the cutting liquid is 20°C. Finally, the uncut part of the crystal rod is cut again using the cutting process before the break. In this comparative example, the process parameters of the crystal rod moving toward the diamond wire and the cutting process before the break are the same as those in Example 3.

[0065] After testing, it was found that serious steps appeared on the surface of the cut silicon wafer, causing the entire crystal rod to be scrapped.

[0066] Comparative Example 9

[0067] A process for re-cutting an 8-inch semiconductor silicon crystal rod after a wire break by diamond wire cutting. First, the diamond wire mesh after the break is connected, and the crystal rod is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is 1 mm above the break position and stops moving. Then, the diamond wire is transitionally cut at a wire speed of 200 m / min and a wire feed of 8 m. During the cutting process, the cutting liquid is sprayed toward the break position of the silicon wafer, and its flow rate is 88 L / min. The temperature of the cutting liquid is 20°C. Finally, the uncut part of the crystal rod is cut again using the cutting process before the break. In this comparative example, the process parameters of the crystal rod moving toward the diamond wire and the cutting process before the break are the same as those in Example 3.

[0068] After testing, it was found that serious steps appeared on the surface of the cut silicon wafer, causing the entire crystal rod to be scrapped.

[0069] Comparative Example 10

[0070] A process for re-cutting an 8-inch semiconductor silicon crystal ingot after a wire break during diamond wire cutting. First, the diamond wire mesh after the wire break is connected, and the crystal ingot is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is 1 mm below the wire break position. Then, the uncut portion of the crystal ingot is cut again using the cutting process before the wire break. In this comparative example, the process parameters for the process of moving the crystal ingot toward the diamond wire and the cutting process before the wire break are the same as those in Example 3.

[0071] After testing, it was found that serious steps appeared on the surface of the cut silicon wafer, causing the entire crystal rod to be scrapped.

[0072] Comparative Example 11

[0073] A process for re-cutting an 8-inch semiconductor silicon crystal rod after a wire break by diamond wire cutting. First, the diamond wire mesh after the break is connected, and the crystal rod is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is 1 mm below the break position and stops moving. Then, the diamond wire is transitionally cut at a wire speed of 8 m / min and a wire feed of 2 m. During the cutting process, the cutting liquid is sprayed toward the break position of the silicon wafer, and its flow rate is 92 L / min. The temperature of the cutting liquid is 20°C. Finally, the uncut part of the crystal rod is cut again using the cutting process before the break. In this comparative example, the process parameters of the crystal rod moving toward the diamond wire and the cutting process before the break are the same as those in Example 3.

[0074] After testing, it was found that serious steps appeared on the surface of the cut silicon wafer, causing the entire crystal rod to be scrapped.

[0075] Comparative Example 12

[0076] A process for re-cutting an 8-inch semiconductor silicon crystal rod after a wire break by diamond wire cutting. First, the diamond wire mesh after the break is connected, and the crystal rod is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is 1.5 mm below the break position and stops moving. Then, the diamond wire is transitionally cut at a wire speed of 45 m / min and a wire feed of 4 m. During the cutting process, the cutting liquid is sprayed toward the break position of the silicon wafer, and its flow rate is 92 L / min. The temperature of the cutting liquid is 20°C. Finally, the uncut part of the crystal rod is cut again using the cutting process before the break. In this comparative example, the process parameters of the crystal rod moving toward the diamond wire and the cutting process before the break are the same as those in Example 3.

[0077] After testing, it was found that serious steps appeared on the surface of the cut silicon wafer, causing the entire crystal rod to be scrapped.

[0078] Comparative Example 13

[0079] A process for re-cutting an 8-inch semiconductor silicon crystal rod after a wire break by diamond wire cutting. First, the diamond wire mesh after the break is connected, and the crystal rod is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is 1.5 mm below the break position and stops moving. Then, the diamond wire is transitionally cut at a wire speed of 95 m / min and a wire feed of 6 m. During the cutting process, the cutting liquid is sprayed toward the break position of the silicon wafer, and its flow rate is 90 L / min. The temperature of the cutting liquid is 20°C. Finally, the uncut part of the crystal rod is cut again using the cutting process before the break. In this comparative example, the process parameters of the crystal rod moving toward the diamond wire and the cutting process before the break are the same as those in Example 3.

[0080] After testing, it was found that serious steps appeared on the surface of the cut silicon wafer, causing the entire crystal rod to be scrapped.

[0081] Comparative Example 14

[0082] A process for re-cutting an 8-inch semiconductor silicon crystal rod after a wire break by diamond wire cutting. First, the diamond wire mesh after the break is connected, and the crystal rod is controlled to move toward the diamond wire so that the diamond wire enters the corresponding silicon wafer gap until the diamond wire is 1.5 mm below the break position and stops moving. Then, the diamond wire is transitionally cut at a wire speed of 200 m / min and a wire feed of 8 m. During the cutting process, the cutting liquid is sprayed toward the break position of the silicon wafer, and its flow rate is 88 L / min. The temperature of the cutting liquid is 20°C. Finally, the uncut part of the crystal rod is cut again using the cutting process before the break. In this comparative example, the process parameters of the crystal rod moving toward the diamond wire and the cutting process before the break are the same as those in Example 3.

[0083] After testing, it was found that serious steps appeared on the surface of the cut silicon wafer, causing the entire crystal rod to be scrapped.

[0084] Result analysis:

[0085] The difference between Comparative Example 1 and the experimental example is that the experimental example first performs transition cutting. The results show that without transition cutting, direct cutting with the pre-break process will produce slight steps, and the warpage is 13μm larger than the warpage of the silicon wafer obtained by cutting without breaking the line.

[0086] Compared with the experimental examples, the difference between comparative examples 2-4 lies in the different diamond wire speeds. The results show that the diamond wire speeds in comparative examples 2 and 3 are lower than those in the experimental examples. When the diamond wire speed is too low, slight steps appear on the surface of the silicon wafer, and the warping is 12 μm larger than that of the silicon wafer obtained by continuous wire cutting. The diamond wire speed in comparative example 4 is higher than that in the experimental example. When the diamond wire speed is too high, deeper wire marks appear on the surface of the silicon wafer, causing the entire crystal rod to be scrapped. Therefore, during transition cutting, the linear speed of the diamond wire cannot be too slow or too fast. During the transition cutting process, if the linear speed of the diamond wire is too slow, it cannot drive the cutting fluid to form a water curtain. After the cutting fluid flows out from the overflow pipe, it will directly pass through the wire gap between the two adjacent diamond wires, causing the cutting fluid to be unable to enter the gap of the silicon wafer. At the same time, the suction force of the silicon wafer is strong. If the linear speed of the diamond wire is too slow, the cutting fluid cannot be driven into the gap through the diamond wire; if the linear speed of the diamond wire is too fast, since the surface of the diamond wire is covered with diamond micropowder, the cutting ability is very strong. If the linear speed is too fast, it will quickly cut deep wire marks on the surface of the silicon wafer, causing the silicon wafer to be scrapped.

[0087] Compared with the experimental examples, the difference between comparative examples 5-14 lies in the position of the diamond wire in the gap and the diamond wire speed. The results show that when the diamond wire is located above or below the wire break position, no matter what the diamond wire speed is, severe steps will appear on the surface of the silicon wafer when the crystal rod is transition cut, causing the entire crystal rod to be scrapped.

[0088] In summary, the solution of the present invention can obtain a silicon wafer with no wire marks or steps on the surface, and the warpage is similar or equivalent to that of the silicon wafer obtained by continuous wire cutting, thereby solving the problem of surface defects of the silicon wafer after re-cutting.

[0089] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A process for recutting an 8-inch semiconductor silicon ingot after a wire break during diamond wire sawing. First, the diamond wire mesh is connected after the wire break, and the ingot is controlled to move toward the diamond wire at a feed rate of 14 mm / min-16 mm / min, so that the diamond wire enters the corresponding silicon wafer gap. The ingot is controlled to stop moving after the diamond wire reaches the break position. The ingot is then transitionally cut. After the transition is completed, the uncut portion of the ingot is recut using the cutting process before the wire break. In the cutting process before the wire break, the ingot is cut at a feed rate of 0.6 mm / min-1.0 mm / min. The process is characterized by: As the crystal rod moves toward the diamond wire, cutting fluid is sprayed into the gap of the silicon wafer. The flow rate of the cutting fluid is 88L / min-92L / min, and the temperature of the cutting fluid is 20℃-22℃. During the transition cutting, the linear speed of the diamond wire is 90m / min-100m / min, and the cutting fluid is sprayed toward the break position of the silicon wafer, and its flow rate is 88L / min-92L / min, so that the cutting fluid can soak the diamond wire and be brought into the gap of the silicon wafer during the cutting process; the transition cutting is ended when the wire feed amount of the diamond wire is 6m.

2. The process for re-cutting an 8-inch semiconductor silicon ingot after a broken diamond wire saw according to claim 1, characterized in that: The crystal rod moves toward the diamond wire at a feed rate of 15 mm / min.

3. The process for re-cutting an 8-inch semiconductor silicon ingot after a broken diamond wire saw according to claim 1, characterized in that: During the transition cutting, the linear speed of the diamond wire is 93m / min-98m / min.

4. The process for re-cutting an 8-inch semiconductor silicon ingot after a broken diamond wire saw according to claim 1, characterized in that: During the transition cutting, the flow rate of the cutting fluid is 90 L / min.

5. The process for re-cutting an 8-inch semiconductor silicon ingot after a broken diamond wire saw according to claim 1, characterized in that: In the cutting process before the wire breaking, the diamond wire cuts the crystal rod at a wire speed of 1200m / min-1800m / min.

6. The process for re-cutting an 8-inch semiconductor silicon ingot after a broken diamond wire saw according to claim 1, characterized in that: In the cutting process before the wire breaking, during the process of the diamond wire cutting the uncut part of the crystal rod, the flow rate of the cutting liquid is 88L / min-92L / min. After the cutting liquid flows onto the diamond wire mesh through the overflow pipe, the cutting liquid soaks the diamond wire and can be brought into the gaps of the silicon wafer during the cutting process. The temperature of the cutting liquid is 20℃-22℃.