A cutting method for large-sized silicon wafers

Abstract

The present invention belongs to the technical field of solar energy, and relates to a cutting method for large-sized silicon wafers. After removing the head and tail of a single crystal ingot, the single crystal ingot is cut into a plurality of cubic ingots along the axial line direction of the single crystal ingot. Each cubic ingot has at least two sides with the same side length as that of other cubic ingots. Then, the cubic ingot is sliced along the side with a side length different from that of other cubic ingots to obtain rectangular silicon wafers. The present invention provides a method for producing large-sized silicon wafers using a small furnace type, enabling various furnace types to produce large silicon wafers with flexible and adjustable sizes, and improving the silicon material utilization rate of the silicon ingot.

Description

Technical Field

[0001] The invention belongs to the technical field of solar energy and relates to a method for cutting a large-size silicon wafer. Background Art

[0002] At present, the components in the industry are constantly developing in the direction of higher power. In addition to the improvement of battery efficiency and component packaging technology, the size of silicon wafers is also constantly upgraded to support higher power and lower cost component products. The size of silicon wafers has been upgraded from 125mm at the beginning to 156mm and 158mm, and from 2018 to 163mm and 166mm. In 2019, it even began to develop to 182mm, 210mm-230mm. The entire industry chain is constantly upgrading, and the problem that comes with it is that the production capacity of old equipment is constantly being eliminated. In order to pull larger crystal rods to obtain larger silicon wafers, single crystal furnaces are constantly upgraded from 80 furnace types to 90, 100, 105, 110, 120, 140, and 160 furnace types. Furnaces below 105 can only prepare silicon wafer crystal rods below 166mm, furnaces below 120 cannot prepare 182mm silicon wafer crystal rods, and furnaces below 140 cannot prepare 210mm and silicon wafer crystal rods. Various equipment on the market has huge production capacity. Even if a 140 furnace is used to produce 210mm crystal rods, it will cost hundreds of thousands to transform the equipment, which is very expensive. Summary of the invention

[0003] The object of the present invention is to provide a method for cutting large-size silicon wafers in view of the above problems.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for cutting large-size silicon wafers includes removing the head and tail of a single crystal rod and then cutting the single crystal rod into a plurality of cubic crystal rods along the axis of the single crystal rod, wherein at least two sides of each cubic crystal rod have the same length as other cubic crystal rods, and then slicing the cubic crystal rod along the side that is different from the side length of other cubic crystal rods to cut into rectangular silicon wafers.

[0006] Furthermore, there are at least three cubes.

[0007] Further, when the effective diameter of the single-wafer rod is greater than one time and less than or equal to three times the target wafer width d, the single-wafer rod is cut into three cubic rods along its axis line. For the larger cubic rod, one side length is d, another side length is h1, and the depth along the axis line of the single-wafer rod is l. For the other two smaller cubic rods, one side length is d, another side length is h2, and the depth along the axis line of the single-wafer rod is l. The larger cubic rod is cut into wafers along the side with length h1, and the larger cubic rod is cut into wafers along the side with length h2, obtaining rectangular wafers with lengths and widths of l and d respectively.

[0008] Further, where d = 60 - 125 mm, l = 156 - 250 mm, and the thickness of the rectangular wafer is 50 - 250 μm.

[0009] Further, when the effective diameter of the single-wafer rod is greater than two times and less than three times the target wafer width d, the round rod is cut into 6 cubic rods. For 2 of the larger cubic rods, one side length is d, another side length is h1, and the depth along the axis line of the single-wafer rod is l; for the other two relatively smaller cubes, one side length is d, another side length is h2, and the depth along the axis line of the single-wafer rod is l; for the other two relatively smaller cubes, one side length is d, another side length is h3, and the depth along the axis line of the single-wafer rod is l. The 6 cubic rods are respectively cut into wafers along the sides with lengths h1, h2, and h3, obtaining rectangular wafers with lengths and widths of l and d respectively.

[0010] Further, where d = 60 - 125 mm, l = 156 - 250 mm, and the thickness of the rectangular wafer is 50 - 250 μm.

[0011] Further, when the effective diameter of the single-wafer rod is greater than three times the target wafer width d, the round rod is cut into 5 cubic rods. For one of the cubic rods, one side length is d, another side length is h1, and the depth along the axis line of the single-wafer rod is l; for two of the cubic rods, one side length is d, another side length is h2, and the depth along the axis line of the single-wafer rod is l; for the remaining two cubic rods, one side length is d, another side length is h3, and the depth along the axis line of the single-wafer rod is l. The 5 cubic rods are respectively cut into wafers along the sides with lengths h1, h2, and h3, obtaining rectangular wafers with lengths and widths of l and d respectively.

[0012] Further, where d = 60 - 125 mm, l = 156 - 250 mm, and the thickness of the rectangular wafer is 50 - 250 μm.

[0013] Further, when the effective diameter of the single-wafer rod is greater than three times the target wafer width d, the round rod is cut into 11 cubic rods. Among them, three cubic rods have a side length of d and a side length of h1, and the depth along the axis line of the single-wafer rod is l. Four cubic rods have a side length of d and a side length of h2, and the depth along the axis line of the single-wafer rod is l. The remaining four cubic rods have a side length of d and a side length of h3, and the depth along the axis line of the single-wafer rod is l. The 11 cubic rods are respectively cut along the sides with lengths of h1, h2, and h3 to obtain rectangular wafers with lengths of l and widths of d.

[0014] Further, among them, d = 60 - 125 mm, l = 156 - 250 mm, and the thickness of the rectangular wafer is 50 - 250 μm.

[0015] Compared with the existing technology, the advantages of the present invention are as follows:

[0016] The present invention provides a method for producing large-size wafers using a small furnace type, enabling various furnace types to produce large wafers with flexible and adjustable sizes, and improving the silicon material utilization rate of the silicon rod.

[0017] Other advantages, objectives, and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the cutting method when the effective diameter of the single-wafer rod of the present invention is greater than one time and less than or equal to three times the target wafer width d.

[0019] Figure 2 It is a schematic diagram of the cutting method when the effective diameter of the single-wafer rod of the present invention is greater than two times and less than three times the target wafer width d.

[0020] Figure 3 It is a schematic diagram of the cutting method when the effective diameter of the single-wafer rod of the present invention is greater than three times the target wafer width d.

[0021] Figure 4 It is another schematic diagram of the cutting method when the effective diameter of the single-wafer rod of the present invention is greater than three times the target wafer width d. Detailed Embodiments

[0022] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention.

[0023] Embodiment 1

[0024] A single crystal ingot is obtained by the Czochralski method. The head and tail of the single crystal ingot are removed. As Figure 1 shown, when the effective diameter of the single crystal ingot is greater than one time and less than or equal to three times the target wafer width d, the round ingot is cut into 3 cubic ingots. One side length of the larger cubic ingot is d, and the other side length is h1. The depth of the cube along the longitudinal axis of the ingot is l. For the other two relatively smaller cubes, one side length is d, and the other side length is h2. The depth of the cube along the longitudinal axis of the ingot is l. The entire silicon ingot is cut into 3 cubic ingots with a length of l in the longitudinal length direction. After the cubic ingots are prepared, they are cut into rectangular wafers. The short side width of the cut wafer is d, ranging from 60 mm to 125 mm. The long side width of the cut wafer is l, ranging from 156 to 250 mm. The wafer thickness is 50 μm to 250 μm. The side lengths h1 and h2 of the cube are determined by the diameter of the ingot and the size of the wafer, making the most of the length that the round ingot can achieve. The cubic ingots can be cut by a band saw or a wire saw, and the wafers are cut by a wire saw.

[0025] Example 2

[0026] When the effective diameter of the single crystal ingot is greater than two times and less than three times the target wafer width d, a single crystal ingot is obtained by the Czochralski method. The head and tail of the single crystal ingot are removed. As Figure 2 shown, the single crystal ingot is longitudinally cut along the axis line, and the round ingot is cut into 6 cubic ingots. For 2 of the larger cubic ingots, one side length is d, and the other side length is h1. The depth of the cube along the longitudinal axis of the ingot is l. For the other two relatively smaller cubes, one side length is d, and the other side length is h2. The depth of the cube along the longitudinal axis of the single crystal ingot is l. For the other two relatively smaller cubes, one side length is d, and the other side length is h3. The depth of the cube along the longitudinal axis of the single crystal ingot is l. The entire single silicon ingot is cut into 6 cubes with a length of l in the longitudinal length direction. After the cubes are prepared, they are cut into rectangular wafers. The short side width of the cut wafer is d, ranging from 60 mm to 125 mm. The long side width of the cut wafer is l, ranging from 156 to 250 mm. The wafer thickness is 50 μm to 250 μm. The side lengths h1, h2, and h3 of the cube are determined by the diameter of the ingot and the size of the wafer, making the most of the length that the single crystal ingot can achieve. The cubic ingots can be cut by a band saw or a wire saw, and the wafers are cut by a wire saw.

[0027] Example 3

[0028] A single crystal ingot is obtained by the Czochralski method. The head and tail of the single crystal ingot are removed. When the effective diameter of the single crystal ingot is greater than three times the target wafer width d, as Figure 3As shown in the figure, a round bar is cut into 5 cubic ingots. One of the cubic ingots has a side length of d and a side length of h1, and the depth of the cube along the longitudinal axis of the single crystal ingot is l. Two of them have a side length of d and a side length of h2, and the depth of the cube along the longitudinal axis of the ingot is l. The remaining two have a side length of d and a side length of h3, and the depth of the cube along the longitudinal axis of the ingot is l. The entire single crystal silicon round bar is cut into 5 cubes with a length of l in the longitudinal length direction. After the cubic ingots are prepared, they are cut into rectangular silicon wafers along the sides with lengths of h1, h2, and h3. The short side width of the cut silicon wafer is d, ranging from 60 mm to 125 mm, the long side width of the cut silicon wafer is l, ranging from 156 to 250 mm, and the silicon wafer thickness is 50 μm to 250 μm. The side lengths h1, h2, and h3 of the cube are determined by the diameter of the round bar and the size of the silicon wafer, making the best use of the length that the round bar can achieve. The cubic ingot can be cut by a band saw or a wire saw, and the silicon wafer is cut by a wire saw.

[0029] Example 4

[0030] A single crystal ingot is obtained by the Czochralski method. The head and tail of the single crystal ingot are removed. When the effective diameter of the single crystal ingot is more than three times the width d of the target silicon wafer, as Figure 4 shown in the figure, the round bar is cut into 11 cubic ingots. Three of the cubic ingots have a side length of d and a side length of h1, and the depth of the cube along the longitudinal axis of the ingot is l. Four of them have a side length of d and a side length of h2, and the depth of the cube along the longitudinal axis of the ingot is l. The remaining four have a side length of d and a side length of h3, and the depth of the cube along the longitudinal axis of the ingot is l. The entire single crystal ingot is cut into 11 cubes with a length of l in the longitudinal length direction. After the cubic ingots are prepared, they are cut into rectangular silicon wafers along the sides with lengths of h1, h2, and h3. The short side width of the cut silicon wafer is d, ranging from 60 mm to 125 mm, the long side width of the cut silicon wafer is l, ranging from 156 to 250 mm, and the silicon wafer thickness is 50 μm to 250 μm. The side lengths h1, h2, and h3 of the cube are determined by the diameter of the round bar and the size of the silicon wafer, making the best use of the length that the round bar can achieve. The cubic ingot can be cut by a band saw or a wire saw, and the silicon wafer is cut by a wire saw.

[0031] Example 5

[0032] The effective diameter of the silicon ingot normally used for preparing 158.75 mm silicon wafers is 224.5 mm. During the straightening process of the actual ingot, the diameter cannot be completely controlled to be consistent. Therefore, the diameter of the round ingot will be between 224.5 mm and 228 mm. After square chamfering and grinding with the conventional method, a square ingot with a small chamfer of 158.75 mm is obtained. The ingot is sliced along the square cross-section to obtain 158.7 mm square silicon wafers. The utilization rate of the slicable ingot silicon material is about 60.7%. After preparing 105*210 size silicon wafers by the method of Example 1, the utilization rate of the slicable silicon material is increased to 74.1%, and the silicon material utilization rate is increased by 13.4%. First, remove the head and tail of the silicon round ingot with an effective diameter of 224.5. The whole silicon round ingot is cut into several cubes with a length of l = 210 mm in the longitudinal length direction. Looking at the circular cross-section, the round ingot is cut into 3 cube-shaped square ingots. One side length of the larger cube ingot is d = 105 mm, and one side length is h1 = 199 mm. The depth of the cube along the longitudinal axis of the ingot is l = 210 mm. The other two relatively small cubes have one side length of d = 105 mm and one side length of h2 = 47 mm. The depth of the cube along the longitudinal axis of the ingot is l = 210 mm. After the cube preparation is completed, chamfering can be carried out on the edge line perpendicular to the silicon wafer surface as needed to avoid too high a fragmentation rate during the silicon wafer processing. The silicon ingot is cut into rectangular silicon wafers, and the size of the cut silicon wafer is 105*210 mm, and the silicon wafer thickness is 180 ± 20 μm. The cube-shaped square ingot can be cut by a band saw or a diamond wire, and the silicon wafer is cut by a diamond wire.

[0033] Example 6

[0034] The effective diameter of the silicon ingot normally used for preparing 210mm silicon wafers is 297mm. During the straightening process of the actual ingot, the diameter cannot be completely controlled to be consistent. Therefore, the diameter of the round ingot will be between 297mm and 300mm. After square chamfering and surface grinding by conventional methods, a square ingot with a small chamfer of 210mm is obtained. The ingot is sliced along the square section to obtain 210mm square silicon wafers. The utilization rate of the slicable silicon material is about 62.4%. After preparing 105mm*210mm silicon wafers by the method of Example 1, the utilization rate of the slicable silicon material is increased to about 66.7%, and the utilization rate of the silicon material is increased by 4.3%. First, the silicon round ingot with an effective diameter of 297 is cut off at both ends. The whole silicon round ingot is cut into several cubes with a length of l = 210mm in the longitudinal length direction. Looking from the circular section, the round ingot is cut into 3 cube-shaped square bars. One side length of the larger cube ingot is d = 105mm, and the other side length is h1 = 277mm. The depth of the cube along the longitudinal axis of the ingot is l = 210mm. For the other two relatively small cubes, one side length is d = 105mm, and the other side length is h2 = 86mm. The depth of the cube along the longitudinal axis of the ingot is l = 210mm. After the cube preparation is completed, chamfering can be carried out on the edge line perpendicular to the silicon wafer surface as needed to avoid too high a fragmentation rate during the silicon wafer processing. The silicon bar is cut into rectangular silicon wafers, and the size of the cut silicon wafer is 105mm*210mm, and the thickness of the silicon wafer is 180±20μm. The cube-shaped square bar can be cut by a band saw or a wire saw, and the silicon wafer is cut by a wire saw.

[0035] Example 7

[0036] The effective diameter of the silicon ingot normally used for preparing 210mm silicon wafers is 297mm. During the straightening process of the actual ingot, the diameter cannot be completely controlled to be consistent. Therefore, the diameter of the round ingot will be between 297mm and 300mm. After the conventional method of square root chamfering and surface grinding, a square ingot with a small chamfer of 210mm is obtained. The ingot is sliced along the square cross-section to obtain 210mm square silicon wafers. The utilization rate of the slicable ingot silicon material is about 62.4%. After using the method of Example 2 to prepare 105mm*210mm size silicon wafers, the utilization rate of the slicable silicon material is increased to about 82%, and the silicon material utilization rate is increased by 19.6%. First, remove the head and tail of the silicon round ingot with an effective diameter of 297. The whole silicon round ingot is cut into several cubes with a length of l = 210mm in the longitudinal length direction. Looking from the circular cross-section, the round ingot is cut into 6 cube-shaped square ingots. One side length of the larger cube-shaped ingot is d = 105mm, and one side length is h1 = 210mm. The depth of the cube along the longitudinal axis of the ingot is l = 210mm. The other 4 relatively small cubes have one side length of d = 105mm, one side lengths of h2 = h3 = 33mm, and the depth of the cube along the longitudinal axis of the ingot is l = 210mm. After the cube preparation is completed, chamfering can be carried out on the edge line perpendicular to the silicon wafer surface as needed to avoid too high a fragmentation rate during the silicon wafer processing. The silicon ingot is cut into rectangular silicon wafers, and the size of the cut silicon wafer is 105mm*210mm, and the silicon wafer thickness is 180±20μm. The cube-shaped square ingot can be cut by a band saw or a wire saw, and the silicon wafer is cut by a wire saw.

[0037] Example 8

[0038] The effective diameter of the silicon ingot normally used for preparing 210mm silicon wafers is 297mm. During the straightening process of the actual ingot, the diameter cannot be completely controlled to be consistent. Therefore, the diameter of the round ingot will be between 297mm and 300mm. After square chamfering and surface grinding by conventional methods, a square ingot with a small chamfer of 210mm is obtained. The ingot is sliced along the square section to obtain 210mm square silicon wafers. The utilization rate of the slicable silicon material of the ingot is about 62.4%. By using the method of Example 2, silicon wafers with a size larger than 210 can be prepared. After making the silicon rod into silicon wafers with a size of 105mm * 217mm, the utilization rate of the slicable silicon material is increased to about 82%, and the utilization rate of the silicon material is increased by 4.3%. First, the silicon round ingot with an effective diameter of 297 is cut off at both ends. The whole silicon round ingot is cut into several cubes with a length of l = 217mm in the longitudinal length direction. Looking from the circular section, the round ingot is cut into 6 cube-shaped square rods. One side length of the larger cube-shaped ingot is d = 105mm, and one side length is h1 = 210mm. The depth of the cube along the longitudinal axis of the ingot is l = 217mm. The other 4 relatively small cubes have one side length of d = 105mm and one side lengths of h2 = h3 = 33mm. The depth of the cube along the longitudinal axis of the ingot is l = 217mm. After the cube preparation is completed, chamfering can be carried out on the edge line perpendicular to the silicon wafer surface as needed to avoid too high a chip rate during the silicon wafer processing. The silicon rod is cut into rectangular silicon wafers, and the size of the cut silicon wafer is 105mm * 217mm, and the silicon wafer thickness is 180 ± 20μm. The cube-shaped square rods can be cut by a band saw or a wire saw, and the silicon wafers are cut by a wire saw.

[0039] Example 9

[0040] The effective diameter of the silicon ingot normally used for preparing 166 mm silicon wafers is 235 mm. During the straightening process of the actual ingot, the diameter cannot be completely controlled to be consistent. Therefore, the diameter of the round ingot will be between 235 mm and 238 mm. After square chamfering and surface grinding by conventional methods, a square ingot with a small chamfer of 166 mm is obtained. The ingot is sliced along the square section to obtain 166 mm square silicon wafers. The utilization rate of the slicable ingot silicon material is about 62%. After preparing 105 mm * 218 mm silicon wafers by the method of Example 1, the utilization rate of the slicable silicon material is increased to about 74%, and the utilization rate of the silicon material is increased by 12%. First, the silicon round ingot with an effective diameter of 235 mm has its head and tail removed. The whole silicon round ingot is cut into several cubes with a length of l = 218 mm in the longitudinal length direction. Looking from the circular section, the round ingot is cut into 3 cube-shaped square ingots. One side length of the larger cube ingot is d = 105 mm, and one side length is h1 = 210 mm. The depth of the cube along the longitudinal axis of the ingot is l = 218 mm. The other 2 relatively small cubes have one side length of d = 105 mm and one side length of h2 = 52 mm. The depth of the cube along the longitudinal axis of the ingot is l = 218 mm. After the cubes are prepared, chamfering can be carried out on the edges perpendicular to the silicon wafer surface as needed to avoid too high a fragmentation rate during the wafer processing. The silicon ingot is cut into rectangular silicon wafers, and the size of the cut silicon wafers is 105 mm * 218 mm, and the wafer thickness is 180 ± 20 μm. The cube-shaped square ingots can be cut by a band saw or a wire saw, and the silicon wafers are cut by a wire saw.

[0041] Example 10

[0042] The effective diameter of the silicon ingot rod normally used for preparing 166 mm silicon wafers is 235 mm. During the straightening process of the actual ingot rod, the diameter cannot be completely controlled to be consistent. Therefore, the diameter of the round rod will be between 235 mm and 238 mm. After square chamfering and surface grinding by conventional methods, a square ingot rod with a small chamfer of 166 mm is obtained. The ingot rod is sliced along the square cross-section to obtain 166 mm square silicon wafers. The utilization rate of the slicable ingot silicon material is about 62%. After using the method of Example 1 to prepare 91 mm * 182 mm size silicon wafers, the utilization rate of the slicable silicon material is increased to about 70%, and the utilization rate of the silicon material is increased by 8%. First, for a silicon round rod with an effective diameter of 235 mm, the head and tail are removed. The whole silicon round rod is cut into several cubes with a length of l = 182 mm in the longitudinal length direction. From the circular cross-section view, the round rod is cut into 3 cube-shaped square rods. Among them, for the larger cube-shaped ingot rod, one side length is d = 91 mm, and one side length is h1 = 216 mm. The depth of the cube along the longitudinal axis of the ingot rod is l = 182 mm. For the other 2 relatively small cubes, one side length is d = 91 mm, and one side length is h2 = 63 mm. The depth of the cube along the longitudinal axis of the ingot rod is l = 182 mm. After the cube preparation is completed, chamfering can be carried out on the edge line perpendicular to the silicon wafer surface as needed to avoid too high a fragmentation rate during the silicon wafer processing. The silicon rod is cut into rectangular silicon wafers, and the size of the cut silicon wafer is 91 mm * 182 mm, and the thickness of the silicon wafer is 180 ± 20 μm. The cube-shaped square rod can be cut by a band saw or a wire saw, and the silicon wafer is cut by a wire saw.

[0043] Example 11

[0044] The effective diameter of the silicon ingot rod normally used for preparing 210 mm silicon wafers is 297 mm. During the straightening process of the actual ingot rod, the diameter cannot be completely controlled to be consistent. Therefore, the diameter of the round rod will be between 297 mm and 300 mm. After square chamfering and surface grinding by conventional methods, a square ingot rod with a small chamfer of 210 mm is obtained. The ingot rod is sliced along the square cross-section to obtain 210 mm square silicon wafers. The utilization rate of the silicon material for the sliceable ingot rod is about 62.4%. By using the method of Example 3, silicon wafers with a size larger than 210 can be prepared. After making the silicon rod into silicon wafers with a size of 70 mm * 217 mm, the utilization rate of the sliceable silicon material is increased to about 77.9%, and the utilization rate of the silicon material is increased by 15.5%. First, remove the head and tail of the silicon round rod with an effective diameter of 297. The whole silicon round rod is cut into several cubes with a length of l = 217 mm in the longitudinal length direction. Looking from the circular cross-section, the round rod is cut into 6 cube-shaped square rods. One side length of the larger cube ingot rod is d = 70 mm, and one side length is h1 = 288 mm. The depth of the cube along the longitudinal axis of the ingot rod is l = 217 mm. For the other 2 relatively small cubes, one side length is d = 70 mm, and one side length is h2 = 210 mm. The depth of the cube along the longitudinal axis of the ingot rod is l = 217 mm. For the remaining 2 smallest cubes, one side length is d = 70 mm, and one side length is h3 = 39 mm. The depth of the cube along the longitudinal axis of the ingot rod is l = 217 mm. After the cube preparation is completed, chamfering can be carried out on the edge lines perpendicular to the silicon wafer surface as needed to avoid too high a fragmentation rate during the silicon wafer processing. The silicon rod is cut into rectangular silicon wafers, and the size of the cut silicon wafers is 70 mm * 217 mm, and the thickness of the silicon wafer is 180 ± 20 μm. The cube-shaped square rods can be cut by a band saw or a diamond wire, and the silicon wafers are cut by a diamond wire.

[0045] Example 12

[0046] The effective diameter of the silicon ingot normally used for preparing 210 mm silicon wafers is 297 mm. During the straightening process of the actual ingot, the diameter cannot be completely controlled to be consistent. Therefore, the diameter of the round ingot will be between 297 mm and 300 mm. After square chamfering and surface grinding by conventional methods, a square ingot with a small chamfer of 210 mm is obtained. The ingot is sliced along the square section to obtain 210 mm square silicon wafers. The utilization rate of the silicon material for the sliceable ingot is about 62.4%. Using the method of Example 4, silicon wafers with a size larger than 210 can be prepared. After the silicon rod is made into silicon wafers with a size of 70 mm * 218 mm, the utilization rate of the sliceable silicon material is increased to about 82.2%, and the utilization rate of the silicon material is increased by 19.8%. First, the silicon round ingot with an effective diameter of 297 is cut off at both ends. The whole silicon round ingot is cut into several cubes with a length of l = 218 mm in the longitudinal length direction. Looking from the circular section, the round ingot is cut into 11 cube-shaped square rods. Among them, the three larger cube-shaped ingots have one side length of d = 70 mm and one side length of h1 = 210 mm. The depth of the cube along the longitudinal axis of the ingot is l = 218 mm. The other eight relatively small cubes have one side length of d = 70 mm and one side length of h2 = h3 = 25 mm. The depth of the cube along the longitudinal axis of the ingot is l = 218 mm. After the cubes are prepared, chamfering can be carried out on the edge lines perpendicular to the silicon wafer surface as needed to avoid too high a fragmentation rate during the processing of the silicon wafers. The silicon rod is cut into rectangular silicon wafers, and the size of the silicon wafers after cutting is 70 mm * 218 mm, and the thickness of the silicon wafers is 180 ± 20 μm. The cube-shaped square rods can be cut by a band saw or a wire saw, and the silicon wafers are cut by a wire saw.

[0047] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, but will not deviate from the spirit of the present invention.

Claims

1. A cutting method for large-sized silicon wafers, characterized in that After removing the head and tail of a single-wafer rod, the single-wafer rod is cut along the axial line of the single-wafer rod into a number of cubic crystal rods with a length of l. Each cubic crystal rod has at least two sides with a side length d that is the same as that of other cubic crystal rods. Then, the cubic crystal rod is sliced along the side that is different from the side lengths of other cubic crystal rods, cutting into rectangular silicon wafers with lengths and widths of l and d respectively. When the effective diameter of the single-wafer rod is greater than twice the target wafer width d and less than three times the target wafer width d, the round rod is cut into 6 cubic square rods. For 2 of the larger cubic crystal rods, one side length is d and the other side length is h1, and the depth along the axial line of the single-wafer rod is l. For the other two relatively smaller cubes, one side length is d and the other side length is h2, and the depth along the axial line of the single-wafer rod is l. For the other two relatively smaller cubes, one side length is d and the other side length is h3, and the depth along the axial line of the single-wafer rod is l. The 6 cubic crystal rods are respectively sliced along the sides with lengths h1, h2, and h3 to obtain rectangular silicon wafers with lengths and widths of l and d respectively. When the effective diameter of the single-wafer rod is greater than three times the target wafer width d, the round rod is cut into 5 cubic crystal rods. One of the cubic crystal rods has one side length of d and the other side length of h1, and the depth along the axial line of the single-wafer rod is l. Two of the cubic crystal rods have one side length of d and the other side length of h2, and the depth along the axial line of the single-wafer rod is l. The remaining two cubic crystal rods have one side length of d and the other side length of h3, and the depth along the axial line of the single-wafer rod is l. The 5 cubic crystal rods are respectively sliced along the sides with lengths h1, h2, and h3 to obtain rectangular silicon wafers with lengths and widths of l and d respectively. Or, When the effective diameter of the single-wafer rod is greater than three times the target wafer width d, the round rod is cut into 11 cubic crystal rods. Three of the cubic crystal rods have one side length of d and the other side length of h1, and the depth along the axial line of the single-wafer rod is l. Four of the cubic crystal rods have one side length of d and the other side length of h2, and the depth along the axial line of the single-wafer rod is l. The remaining four cubic crystal rods have one side length of d and the other side length of h3, and the depth along the axial line of the single-wafer rod is l. The 11 cubic crystal rods are respectively sliced along the sides with lengths h1, h2, and h3 to obtain rectangular silicon wafers with lengths and widths of l and d respectively.

2. The cutting method of a large-size silicon wafer according to claim 1, wherein Among them, d = 60 - 125 mm, l = 156 - 250 mm, and the thickness of the rectangular silicon wafer is 50 - 250 μm.

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