Processing method for recycling unqualified silicon rod

Abstract

The invention discloses a processing method for recycling an unqualified silicon rod. The processing method comprises the following steps: marking a chamfering part of four chamfering parts of the unqualified silicon rod, wherein the distance between the chamfering part and the center point of the unqualified silicon rod is smaller than the radius of a square rod before accurate grinding, as an abnormal chamfering part; the two side wall parts adjacent to the abnormal chamfering parts are ground according to the grinding thickness, the ground silicon rod is obtained, the edge width of the ground silicon rod is larger than the edge width before accurate grinding and smaller than the edge width after squaring, and the distances between all the chamfering parts in the ground silicon rod and the center point of the ground silicon rod are larger than the radius of the square rod before accurate grinding; and the ground silicon rod is subjected to coarse grinding and fine grinding, and the finished square rod is obtained. In the embodiment of the invention, all the chamfered parts in the ground silicon rod have grinding amount, so that the situation that normal machining cannot be carried out due to the fact that the chamfered parts do not have the grinding amount is avoided, and the rejection rate of unqualified silicon rods is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaics, and in particular to a processing method for recycling unqualified silicon rods. Background Art

[0002] Monocrystalline silicon rods are the raw materials for producing solar cells. The production method of monocrystalline silicon is usually to first produce polycrystalline silicon or amorphous silicon, and then grow round rod-shaped monocrystalline silicon from the melt using the Czochralski method or the floating zone melting method. The round silicon rods are processed into square finished square rods after squaring, rough grinding and fine grinding.

[0003] At present, when squaring a round silicon rod, the four sides are cut off to form a square with round chamfers. When squaring a round silicon rod, the center of the round silicon rod will frequently shift, resulting in a square silicon rod with center shift. The arc length projections of the chamfers of such square silicon rods are uneven, and the distance from one chamfer to the center is less than the radius of the square rod before fine grinding.

[0004] However, before the integrated grinding and chamfering machine performs rough and fine grinding on the squared silicon rod, it will compare the distance between the chamfer and the center on the squared silicon rod with the radius of the square rod before fine grinding. If the distance between the chamfer and the center is smaller than the radius of the square rod before fine grinding, it will be considered that the squared silicon rod has no grinding amount, and it will be judged as unqualified and rejected. After rejection, it can no longer be processed into finished square rods and can only be directly scrapped as recycled material. Summary of the invention

[0005] The present invention provides a processing method for recycling unqualified silicon rods, aiming to solve the problem in the prior art that if the distance between the chamfer and the center is smaller than the radius of the square rod before fine grinding, the rod will be judged as unqualified and rejected, and can no longer be processed into a finished square rod.

[0006] An embodiment of the present invention provides a processing method for recycling unqualified silicon rods, wherein the unqualified silicon rods include four sidewall portions and four chamfered portions, wherein the sidewall portions and the chamfered portions are alternately connected in sequence, and the processing method for recycling unqualified silicon rods includes:

[0007] Among the four chamfered parts of the unqualified silicon rod, the chamfered part whose distance from the center point of the unqualified silicon rod is less than the radius before fine grinding of the square rod is recorded as an abnormal chamfered part;

[0008] Grinding two sidewall portions adjacent to the abnormal chamfered portion according to the grinding thickness to obtain a ground silicon rod, wherein the side width of the ground silicon rod is greater than the side width before fine grinding and less than the side width after square cutting, and the distance between all chamfered portions in the ground silicon rod and the center point of the ground silicon rod is greater than the radius of the square rod before fine grinding;

[0009] The ground silicon rod is subjected to rough grinding and fine grinding to obtain a finished square rod, wherein the arc length projections of four chamfered portions in the finished square rod are all equal.

[0010] Optionally, after the step of recording the chamfered portion of the four chamfered portions of the unqualified silicon rod whose distance from the center point of the unqualified silicon rod is less than the radius before fine grinding of the square rod as an abnormal chamfered portion, and before the step of grinding two side wall portions adjacent to the abnormal chamfered portion according to the grinding thickness to obtain the ground silicon rod, the method further includes:

[0011] Recording one of the chamfered portions adjacent to the abnormal chamfered portion as a reference chamfered portion;

[0012] When the ratio of the arc length projection of the abnormal chamfered portion to the arc length projection of the reference chamfered portion satisfies a preset range, the grinding thickness is determined according to the arc length projection of the abnormal chamfered portion and the arc length projection of the reference chamfered portion.

[0013] Optionally, the number of the abnormal chamfered portions is one, the side width of the ground silicon rod is greater than or equal to the side width after square root cutting -0.7 mm, and the side width after square root cutting is 183 mm-183.4 mm.

[0014] Optionally, the preset range is 1.1-1.3; and determining the grinding thickness according to the arc length projection of the abnormal chamfered portion and the arc length projection of the reference chamfered portion includes:

[0015] When the ratio of the arc length projection of the abnormal chamfered portion to the arc length projection of the reference chamfered portion is greater than 1.1 and less than 1.3, the grinding thickness is greater than 0.3 mm and less than 0.7 mm.

[0016] Optionally, the determining the grinding thickness according to the arc length projection of the abnormal chamfered portion and the arc length projection of the reference chamfered portion further includes:

[0017] When the ratio of the arc length projection of the abnormal chamfered portion to the arc length projection of the reference chamfered portion is equal to 1.1, the grinding thickness is 0.3 mm.

[0018] Optionally, the determining the grinding thickness according to the arc length projection of the abnormal chamfered portion and the arc length projection of the reference chamfered portion further includes:

[0019] When the ratio of the arc length projection of the abnormal chamfered portion to the arc length projection of the reference chamfered portion is equal to 1.3, the grinding thickness is 0.7 mm.

[0020] Optionally, after the step of rough grinding and fine grinding the ground silicon rod to obtain a finished square rod, the step further includes:

[0021] The finished square rod is sliced ​​to obtain a plurality of silicon wafers.

[0022] Optionally, grinding two side wall portions adjacent to the abnormal chamfered portion according to the grinding thickness to obtain a ground silicon rod comprises:

[0023] According to the grinding thickness, two side wall portions adjacent to the abnormal chamfered portion are ground by a grinding and chamfering integrated machine to obtain a ground silicon rod.

[0024] Optionally, the rough grinding and fine grinding of the ground silicon rod to obtain a finished square rod comprises:

[0025] The ground silicon rods are coarsely ground and finely ground by a grinding and turning machine to obtain finished square rods.

[0026] Optionally, the surface roughness of the chamfered portion and the side wall portion of the finished square rod is ≤0.2 μm.

[0027] In the embodiment of the present invention, after grinding the two side wall portions adjacent to the abnormal chamfered portion, the center point of the silicon rod will change, that is, the center point of the ground silicon rod changes compared to the center point of the unqualified silicon rod, so that the distance between all chamfered portions in the ground silicon rod and the center point of the ground silicon rod is greater than the radius before fine grinding of the square rod, and then all chamfered portions in the ground silicon rod have a grinding amount, so the finished square rod can be obtained after rough grinding and fine grinding of the ground silicon rod. In the embodiment of the present invention, all chamfered portions in the ground silicon rod have a grinding amount, which avoids the inability to perform normal processing due to the lack of grinding amount on the chamfered portion, reduces the scrap rate of unqualified silicon rods, reduces manufacturing costs, and solves the problem that unqualified silicon rods can no longer be processed into finished square rods.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of normal cutting of a round silicon rod when squaring in the prior art;

[0030] Figure 2 A flowchart of the steps of a processing method for recycling unqualified silicon rods provided in an embodiment of the present invention;

[0031] Figure 3 A flowchart of the steps of another processing method for recycling unqualified silicon rods provided by an embodiment of the present invention;

[0032] Figure 4 A schematic structural diagram of an unqualified silicon rod after square cutting provided by an embodiment of the present invention;

[0033] Figure 5 A schematic diagram of the structure of an unqualified silicon rod before and after grinding provided by an embodiment of the present invention;

[0034] Figure 6 A schematic structural diagram of a finished square rod provided in an embodiment of the present invention.

[0035] Reference numerals:

[0036] 10-unqualified silicon rod, 11-abnormal chamfered portion, 12-reference chamfered portion, 13-first chamfered portion, 14-second chamfered portion, 15-first side wall portion, 16-second side wall portion, 17-third side wall portion, 18-fourth side wall portion, 20-finished square rod. DETAILED DESCRIPTION

[0037] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0038] Figure 1 The circle in the figure represents the outer circle of the round silicon rod, and the dotted line represents the cutting line. Figure 1 When the squarer is used to square the round silicon rod, the four sides will be cut off and the rod will be cut into a square with rounded chamfers. Figure 1 When the squaring process is normal, the arc length projections of the four chamfers of the qualified square silicon rod obtained after squaring are uniform, and the distance between each chamfer and the center point of the qualified square silicon rod is greater than the radius of the square rod before fine grinding. After the qualified square silicon rod is processed by the grinding and chamfering integrated machine, a finished square rod is obtained.

[0039] However, when squaring a round silicon rod, due to the accuracy of the squaring machine and the round silicon rod itself, the center of the round silicon rod will frequently shift, resulting in square silicon rods with frequent center shifts. Figure 4 The arc length projections of the chamfers of this type of square silicon rod are uneven, and the arc length projection of one chamfer is larger, so that the distance from the chamfer to the center is smaller than the radius of the square rod before fine grinding.

[0040] Before the integrated grinding and chamfering machine performs rough grinding and fine grinding on the squared silicon rod, it will detect the squared silicon rod. Specifically, the distance between the chamfer and the center of the squared silicon rod will be compared with the radius of the square rod before fine grinding. Only when the distance between all the chamfers and the center of the squared silicon rod is greater than the radius before fine grinding, the detection passes, and rough grinding and fine grinding will begin, and the chamfering will be completed in one grinding step.

[0041] When the grinding and chamfering machine detects the silicon rod after square cutting, if the distance between any chamfer and the center of the silicon rod after square cutting is less than the radius before fine grinding of the square rod, it will be considered that the silicon rod after square cutting has no grinding amount, and it will be judged as unqualified and returned to the NG position. After returning, it can no longer be processed into finished square rods and can only be directly scrapped as recycled materials. The scrap rate of unqualified silicon rods is 100%, which increases the manufacturing cost. That is, the processing technology of the existing grinding and chamfering machine can only meet the normal processing of qualified square silicon rods after square cutting, and the above processing technology cannot normally process unqualified silicon rods after square cutting.

[0042] In order to solve the above problems, the embodiment of the present invention provides a processing method for recycling unqualified silicon rods.

[0043] Reference Figure 2 The embodiment of the present invention discloses a processing method for recycling unqualified silicon rods, comprising:

[0044] Step 101: Among the four chamfered parts of the unqualified silicon rod, the chamfered part whose distance from the center point of the unqualified silicon rod is less than the radius before fine grinding of the square rod is recorded as an abnormal chamfered part.

[0045] Specifically, before step 101, the process may further include measuring the distance between each chamfered portion of the squared silicon rod and the center point of the squared silicon rod; if the distance between one of the chamfered portions and the center point of the squared silicon rod is smaller than the radius of the square rod before fine grinding, the squared silicon rod is regarded as an unqualified silicon rod.

[0046] After the round silicon rod is prepared, the head and tail of the round silicon rod are first removed by a squarer, and then the four sides of the round silicon rod are cut off by the squarer to obtain a squared silicon rod. The squared silicon rod includes four sidewalls and four chamfered portions. The distance between the chamfered portion of the squared silicon rod and the center point of the squared silicon rod can be specifically the distance between the midpoint of the chamfered portion of the squared silicon rod and the center point of the squared silicon rod.

[0047] Reference Figure 4 The unqualified silicon rod 10 includes four sidewalls and four chamfers, and the sidewalls and chamfers are connected alternately in sequence. The unqualified silicon rod 10 is made of monocrystalline silicon, which is a single crystal of silicon and is used to manufacture semiconductor devices, solar cells, chips, etc. The chamfers of the unqualified silicon rod 10 are arc chamfers. The distance between the chamfers of the unqualified silicon rod 10 and the center point of the unqualified silicon rod is specifically the distance between the midpoint of the chamfers of the unqualified silicon rod 10 and the center point of the unqualified silicon rod.

[0048] The greater the arc length of the chamfered portion of the unqualified silicon rod 10, the smaller the distance between the chamfered portion and the center point of the unqualified silicon rod. Figure 4The arc length of the chamfered part at the lower left corner is obviously larger, and the distance between the chamfered part and the center point of the unqualified silicon rod is less than the radius of the square rod before fine grinding, so the chamfered part at the lower left corner is recorded as abnormal chamfered part 11. The center point of the unqualified silicon rod can be referred to Figure 5 The distance between the abnormal chamfered portion 11 and the center point C1 of the unqualified silicon rod can be referred to as C1. Figure 5 L1 is shown in the figure, which is smaller than the radius of the square rod before fine grinding.

[0049] The finished square rod 20 also includes four sidewalls and four chamfers. The finished square rod 20 is obtained after a rough grinding process and a fine grinding process. For the finished square rod 20, the finished square rod radius is the radius of the chamfer of the finished square rod 20. The finished square rod radius can be referred to Figure 6 R0 is shown in. R1 represents the radius of the square bar before fine grinding, and d represents the single-side fine grinding amount, then R1=R0+d, wherein the single-side fine grinding amount d is usually 0.05mm-0.2mm, and the radius R0 of the finished square bar can be determined according to actual needs, such as R0 is usually 120mm-135mm.

[0050] Step 102: Grind two side wall portions adjacent to the abnormal chamfered portion according to the grinding thickness to obtain a ground silicon rod.

[0051] Specifically, refer to Figure 4 The two side wall portions adjacent to the abnormal chamfered portion 11 are the first side wall portion 15 and the second side wall portion 16. The grinding area of ​​the first side wall portion 15 and the grinding area of ​​the second side wall portion 16 can be respectively referred to Figure 5 The grinding thickness can be referred to as area a and area b. Figure 5 It should be noted that the grinding thickness of the first side wall portion 15 and the grinding thickness of the second side wall portion 16 may be equal.

[0052] Reference Figure 4 The four chamfered parts of the unqualified silicon rod 10 also include a first chamfered part 13 which is diagonally opposite to the abnormal chamfered part 11. Since the center of the round silicon rod is offset when the square root is taken, the first chamfered part 13 which is diagonally opposite to the abnormal chamfered part 11 with a larger arc length has a smaller arc length. Therefore, the distance L3 between the first chamfered part 13 and the center point C1 of the unqualified silicon rod is much larger than the radius of the square rod before fine grinding. Figure 4 The four chamfered portions of the unqualified silicon rod 10 also include a reference chamfered portion 12 and a second chamfered portion 14. The reference chamfered portion 12 and the second chamfered portion 14 are both normal chamfered portions. Figure 5 The center point C2 of the silicon rod after grinding changes obliquely compared to the center point C1 of the unqualified silicon rod before grinding. For the reference chamfered portion 12 and the second chamfered portion 14, the distance between them and the center point of the silicon rod remains basically unchanged before and after grinding.

[0053] Reference Figure 5 After grinding, the abnormal chamfered portion 11, the reference chamfered portion 12 and the second chamfered portion 14 still have a part left. Figure 5 The center point of the silicon rod after grinding can be referred to Figure 5 When the abnormal chamfered portion 11 is located on the left side, after grinding, the center point C2 of the silicon rod after grinding is located on the upper right side of the center point C1 of the unqualified silicon rod before grinding. Figure 5 Before grinding, the distance between the abnormal chamfered portion 11 and the center point C1 of the unqualified silicon rod is L1. After grinding, the distance between the abnormal chamfered portion 11 and the center point C2 of the ground silicon rod becomes L2, and L2 is greater than L1, thereby making the distance L2 between the abnormal chamfered portion 11 and the center point C2 of the ground silicon rod greater than the radius of the square rod before fine grinding, thereby meeting the subsequent processing requirements.

[0054] Reference Figure 5 Before grinding, the distance between the first chamfered portion 13 and the center point C1 of the unqualified silicon rod is L3. After grinding, the distance between the first chamfered portion 13 and the center point C2 of the ground silicon rod becomes L4. L4 is smaller than L3. However, since L3 is much larger than the radius of the square rod before fine grinding, even after the reduction, the distance between the first chamfered portion 13 and the center point C2 of the ground silicon rod is still larger than the radius of the square rod before fine grinding.

[0055] Reference Figure 5 After squaring and before grinding, the side width of the unqualified silicon rod is W1. After grinding, the side width of the ground silicon rod is W2. W2 is smaller than W1. The units of W2 and W1 are both mm. Figure 6 For finished square bar 20, the edge width of the finished square bar is Figure 6 The W0 shown in the figure can be set according to actual needs. The width W0 of the finished square rod is allowed to have a certain error, such as the width W0 of the finished square rod is usually 182mm±0.25mm. W3 represents the width before fine grinding, then W3=W0+2d, d is the single-sided fine grinding amount mentioned above. According to the above, since the width W0 of the finished square rod is allowed to have a certain error, even if the width of the silicon rod after grinding becomes smaller, as long as the grinding thickness T is controlled so that the width W2 of the silicon rod after grinding is still greater than the width W3 before fine grinding, the side wall of the silicon rod after grinding still has a grinding amount, thereby ensuring that the silicon rod after grinding can be processed normally later.

[0056] The side width of the silicon rod after grinding is larger than the side width before fine grinding, and smaller than the side width after square cutting. The distance between all chamfered parts of the silicon rod after grinding and the center point of the silicon rod after grinding is larger than the radius of the square rod before fine grinding. The side width after square cutting is also the side width of the unqualified silicon rod itself, that is, Figure 5 W1 shown in FIG.

[0057] Step 103 , rough grinding and fine grinding are performed on the ground silicon rod to obtain a finished square rod.

[0058] Specifically, after the unqualified silicon rods are repaired through the above steps 101 and 102, in step 103, the ground silicon rods can be coarsely ground and finely ground by a grinding and grinding machine using conventional processing techniques in the prior art to obtain finished square rods.

[0059] The cross section of the finished square rod 20 is a square with circular chamfers. The four chamfers in the finished square rod 20 are on the same circle, and the arc length projections of the four chamfers in the finished square rod 20 are all equal.

[0060] In the embodiment of the present invention, after grinding the two side wall portions adjacent to the abnormal chamfered portion, the center point of the silicon rod will change, that is, the center point of the ground silicon rod changes compared to the center point of the unqualified silicon rod, so that the distance between all chamfered portions in the ground silicon rod and the center point of the ground silicon rod is greater than the radius before fine grinding of the square rod, and then all chamfered portions in the ground silicon rod have a grinding amount, so the finished square rod can be obtained after rough grinding and fine grinding of the ground silicon rod. In the embodiment of the present invention, all chamfered portions in the ground silicon rod have a grinding amount, which avoids the inability to perform normal processing due to the lack of grinding amount on the chamfered portion, reduces the scrap rate of unqualified silicon rods, reduces manufacturing costs, and solves the problem that unqualified silicon rods can no longer be processed into finished square rods.

[0061] Reference Figure 3 After the step 101 of recording the chamfered portion of the four chamfered portions of the unqualified silicon rod whose distance from the center point of the unqualified silicon rod is less than the radius before fine grinding of the square rod as an abnormal chamfered portion, the step 102 of grinding the two side wall portions adjacent to the abnormal chamfered portion according to the grinding thickness, and before the step of obtaining the ground silicon rod, the step further includes:

[0062] Step 104, recording one of the chamfered portions adjacent to the abnormal chamfered portion as a reference chamfered portion;

[0063] Step 105 , when the ratio of the arc length projection of the abnormal chamfered portion to the arc length projection of the reference chamfered portion satisfies a preset range, determining the grinding thickness according to the arc length projection of the abnormal chamfered portion and the arc length projection of the reference chamfered portion.

[0064] Specifically, the reference chamfer 12 is one of the two chamfers adjacent to the abnormal chamfer 11. The number of abnormal chamfers 11 is one. When taking a square root, the center offset of a circular silicon rod will generally only be biased to one side. The number of abnormal chamfers 11 is usually one, and there is basically no situation where the number of abnormal chamfers 11 is greater than two. Even if the number of abnormal chamfers 11 is greater than or equal to 2, it is difficult to repair unqualified silicon rods with the number of abnormal chamfers 11 greater than or equal to 2, and they are directly scrapped as recycled materials. The reference chamfer 12 and the second chamfer 14 are both normal chamfers. The arc length projection of the abnormal chamfer 11 can be referred to Figure 4 H1 shown in FIG. 1 can be referred to as the arc length projection of the chamfered portion 12. Figure 4 The arc length projection H2 of the reference chamfered portion 12 is equal to the arc length projection of the chamfered portion of the qualified square rod after square root.

[0065] The preset range may be 1.1-1.3. If the ratio of the arc length projection of the abnormal chamfered portion 11 to the arc length projection of the reference chamfered portion 12 is less than 1.1, it means that the size difference between the abnormal chamfered portion 11 and the reference chamfered portion 12 is not large, and the distance between the abnormal chamfered portion 11 and the center point of the silicon rod is still greater than the radius of the square rod before fine grinding. That is, for unqualified silicon rods, there is basically no situation where the ratio of the arc length projection of the abnormal chamfered portion 11 to the arc length projection of the reference chamfered portion 12 is less than 1.1.

[0066] When the ratio of the arc length projection of the abnormal chamfered portion 11 to the arc length projection of the reference chamfered portion 12 is greater than 1.3, even if the two sidewall portions adjacent to the abnormal chamfered portion are ground, after grinding, the side width of the silicon rod or the distance between the chamfered portion and the center point of the silicon rod will not meet the manufacturing requirements. Therefore, the unqualified silicon rods whose ratio of the arc length projection of the abnormal chamfered portion to the arc length projection of the reference chamfered portion is greater than 1.3 are directly scrapped as recycled materials. It should be noted that when taking the square root, the center offset of the circular silicon rod is generally small, that is, the number of unqualified silicon rods whose ratio of the arc length projection of the abnormal chamfered portion to the arc length projection of the reference chamfered portion is greater than 1.3 is extremely small. The processing method for recycling unqualified silicon rods provided in the embodiment of the present invention saves most of the unqualified silicon rods, thereby greatly reducing the scrap rate of unqualified silicon rods.

[0067] The number of abnormal chamfered portions 11 is one, and the side width of the silicon rod after grinding is greater than or equal to the side width after square opening -0.7 mm, and the side width after square opening is 183 mm-183.4 mm.

[0068] Specifically, the side width W2 of the silicon rod after grinding is greater than or equal to the side width after square cutting - 0.7 mm, and the side width W2-0.7 mm after square cutting is still greater than the side width W3 before fine grinding. By setting the side width of the silicon rod after grinding to be greater than or equal to the side width after square cutting - 0.7 mm, the side width of the silicon rod after grinding can be greater than the side width before fine grinding. The side width W1 after square cutting is usually 183.2 mm, and at this time, the side width W2 of the silicon rod after grinding is greater than 182.5 mm.

[0069] In step 105, the grinding thickness is determined according to the arc length projection of the abnormal chamfered portion and the arc length projection of the reference chamfered portion, including:

[0070] When the ratio of the arc length projection of the abnormal chamfered portion to the arc length projection of the reference chamfered portion is greater than 1.1 and less than 1.3, the grinding thickness is greater than 0.3 mm and less than 0.7 mm;

[0071] When the ratio of the arc length projection of the abnormal chamfered part to the arc length projection of the reference chamfered part is equal to 1.1, the grinding thickness is 0.3 mm;

[0072] When the ratio of the arc length projection of the abnormal chamfered portion to the arc length projection of the reference chamfered portion is equal to 1.3, the grinding thickness is 0.7 mm.

[0073] Specifically, the larger the ratio of the arc length projection H1 of the abnormal chamfered portion 11 to the arc length projection H2 of the reference chamfered portion 12, that is, the larger the arc length projection H1 of the abnormal chamfered portion 11, the larger the grinding thickness T. The maximum grinding thickness T is 0.7 mm. When the ratio of the arc length projection H1 of the abnormal chamfered portion 11 to the arc length projection H2 of the reference chamfered portion 12 is greater than 1.1 and less than 1.3, the grinding thickness corresponding to each specific ratio can be determined based on experiments, and the embodiment of the present invention does not make specific limitations, and can ensure that the side width of the silicon rod after grinding is greater than the side width before fine grinding, and less than the side width after square opening, and the distance between all chamfered portions in the ground silicon rod and the center point of the ground silicon rod is greater than the radius of the square rod before fine grinding.

[0074] When the ratio of the arc length projection H1 of the abnormal chamfered portion 11 to the arc length projection H2 of the reference chamfered portion 12 is 1.1, if the side width of the unqualified silicon rod, i.e., the side width W1 after square opening, is 183.2 mm, then after grinding off 0.3 mm, the side width W2 of the ground silicon rod is 182.9 mm. When the ratio of the arc length projection H1 of the abnormal chamfered portion 11 to the arc length projection H2 of the reference chamfered portion 12 is 1.3, if the side width of the unqualified silicon rod, i.e., the side width W1 after square opening, is 183.2 mm, then after grinding off 0.7 mm, the side width W2 of the ground silicon rod is 182.5 mm.

[0075] Reference Figure 3 After the step 103 of rough grinding and fine grinding the ground silicon rod to obtain the finished square rod, the process further includes:

[0076] Step 106, slicing the finished square rod to obtain a plurality of silicon wafers.

[0077] Specifically, the finished square rod can be sliced ​​by a diamond wire mesh arranged on the main stick to obtain a plurality of silicon wafers with uniform thickness.

[0078] Step 102 grinds two sidewalls adjacent to the abnormal chamfered portion according to the grinding thickness to obtain a ground silicon rod, including: grinding two sidewalls adjacent to the abnormal chamfered portion by a grinding and chamfering integrated machine according to the grinding thickness to obtain a ground silicon rod.

[0079] Specifically, when grinding the two adjacent sidewalls of the abnormal chamfered portion 11, a dedicated grinding and chamfering integrated machine can be used for grinding, thereby realizing the repair of unqualified silicon rods. Of course, in other embodiments, other grinding machines can also be used to grind the two adjacent sidewalls of the abnormal chamfered portion 11, as long as the first sidewall portion 15 and the second sidewall portion 16 can be ground off by the grinding thickness T.

[0080] The integrated grinding and chamfering machine may include a loading mechanism for realizing silicon rod loading, a guide rail assembly for clamping the silicon rod, a large guide rail assembly for driving the clamping guide rail assembly to perform the grinding and chamfering process, a rough grinding assembly and a fine grinding assembly corresponding to the silicon rod grinding station, and a discharging mechanism for realizing silicon rod discharging. The integrated grinding and chamfering machine is an integrated surface grinding and chamfering grinder. The integrated grinding and chamfering machine includes a left grinding wheel and a right grinding wheel.

[0081] In the conventional processing technology, the first side wall portion 15, the abnormal chamfered portion 11, the second side wall portion 16 and the second chamfered portion 14 are ground by the left grinding wheel, and the third side wall portion 17, the first chamfered portion 13, the fourth side wall portion 18 and the reference chamfered portion 12 are ground by the right grinding wheel.

[0082] In the embodiment of the present invention, when the first side wall portion 15 and the second side wall portion 16 are ground by the integrated grinding and chamfering machine, the processing mode of the integrated grinding and chamfering machine is changed to plane independent processing without chamfering. When the first side wall portion 15 and the second side wall portion 16 are ground by the integrated grinding and chamfering machine, the first side wall portion 15 and the second side wall portion 16 are placed on the 0° surface and 90° surface of the loading table of the integrated grinding and chamfering machine, and the left grinding wheel is used for grinding, and the right grinding wheel is withdrawn to the -5mm position, that is, the right grinding wheel does not participate in the grinding in step 102.

[0083] When the required finished square rod side width is 182.17 mm and the finished square rod radius is 123.55 mm, when the first side wall portion 15 and the second side wall portion 16 are ground by the grinding and chopping machine, the processing parameters can be adjusted so that the processed side width is the side width W2 of the silicon rod after grinding, such as 182.5 mm. In addition, the value of the square rod radius before fine grinding in the parameters of the grinding and chopping machine during detection can be reduced to allow the detection of unqualified silicon rods to pass.

[0084] Step 103 performs rough grinding and fine grinding on the ground silicon rod to obtain a finished square rod, including: performing rough grinding and fine grinding on the ground silicon rod by a grinding and turning machine to obtain a finished square rod.

[0085] Specifically, the integrated grinding and chamfering machine can adopt the integrated grinding and chamfering machine equipped with conventional processing technology in the prior art. That is, after the unqualified silicon rods are repaired before step 103, the ground silicon rods can be processed according to the conventional processing technology in the last step 103 to obtain finished square rods. The processing method of the conventional processing technology is to complete the plane and chamfering in one machine. The processing parameters of the integrated grinding and chamfering machine can be set to the side width after processing, that is, the side width of the finished square rod is 182.17mm, the radius of the finished square rod is 123.55mm, and the radius of the square rod before fine grinding is the radius of the finished square rod + d.

[0086] The ground silicon rods can be rough-ground and fine-ground by the integrated grinding and chamfering machine, and the polishing of the ground silicon rods can be achieved. When grinding by the integrated grinding and chamfering machine, the flat surface and chamfering can be polished in one clamping, which saves repeated positioning time, improves positioning accuracy, and improves processing efficiency.

[0087] The surface roughness of the chamfered portion and the side wall portion of the finished square rod 20 is both ≤ 0.2 μm.

[0088] Specifically, the ground silicon rod is subjected to rough grinding and fine grinding, that is, the ground silicon rod is polished, and after polishing, the surface roughness of the chamfered part and the side wall of the finished square rod is ≤0.2μm, which meets the manufacturing requirements. After rough grinding and fine grinding, the surface roughness of the chamfered part and the side wall of the finished square rod is ≤0.2μm, and it can be transferred to the slicing process.

[0089] In the embodiment of the present invention, the unqualified silicon rod is repaired by grinding off the two side wall parts adjacent to the abnormal chamfered part, which changes the position of the center point of the silicon rod, so that the distance between all the chamfered parts in the ground silicon rod and the center point of the ground silicon rod is greater than the radius before fine grinding of the square rod, so that each chamfered part has a grinding amount, and each side wall part also has a grinding amount. After the unqualified silicon rod is repaired, it can be processed normally into a finished square rod by the grinding and chamfering machine, thereby greatly reducing the scrap rate of unqualified silicon rods and reducing manufacturing costs.

[0090] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0091] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A processing method for recycling unqualified silicon rods, characterized in that: The unqualified silicon rod comprises four side wall portions and four chamfered portions, wherein the side wall portions and the chamfered portions are alternately connected in sequence, and the processing method for recycling the unqualified silicon rod comprises: Among the four chamfered parts of the unqualified silicon rod, the chamfered part whose distance from the center point of the unqualified silicon rod is less than the radius before fine grinding of the square rod is recorded as an abnormal chamfered part; Grinding two sidewall portions adjacent to the abnormal chamfered portion according to the grinding thickness to obtain a ground silicon rod, wherein the side width of the ground silicon rod is greater than the side width before fine grinding and less than the side width after square cutting, and the distance between all chamfered portions in the ground silicon rod and the center point of the ground silicon rod is greater than the radius of the square rod before fine grinding; The ground silicon rod is subjected to rough grinding and fine grinding to obtain a finished square rod, wherein the arc length projections of four chamfered portions in the finished square rod are all equal.

2. The processing method for recycling unqualified silicon rods according to claim 1, characterized in that: After the step of recording the chamfered portion of the four chamfered portions of the unqualified silicon rod whose distance from the center point of the unqualified silicon rod is less than the radius before fine grinding of the square rod as an abnormal chamfered portion, and before the step of grinding the two side wall portions adjacent to the abnormal chamfered portion according to the grinding thickness to obtain the ground silicon rod, the method further includes: Recording one of the chamfered portions adjacent to the abnormal chamfered portion as a reference chamfered portion; When the ratio of the arc length projection of the abnormal chamfered portion to the arc length projection of the reference chamfered portion satisfies a preset range, the grinding thickness is determined according to the arc length projection of the abnormal chamfered portion and the arc length projection of the reference chamfered portion.

3. The processing method for recycling unqualified silicon rods according to claim 2, characterized in that: The number of the abnormal chamfered portions is one, the side width of the ground silicon rod is greater than or equal to the side width after square cutting-0.7 mm, and the side width after square cutting is 183 mm-183.4 mm.

4. The processing method for recycling unqualified silicon rods according to claim 3, characterized in that: The preset range is 1.1-1.3; the grinding thickness is determined according to the arc length projection of the abnormal chamfered portion and the arc length projection of the reference chamfered portion, including: When the ratio of the arc length projection of the abnormal chamfered portion to the arc length projection of the reference chamfered portion is greater than 1.1 and less than 1.3, the grinding thickness is greater than 0.3 mm and less than 0.7 mm.

5. The processing method for recycling unqualified silicon rods according to claim 4, characterized in that: The determining of the grinding thickness according to the arc length projection of the abnormal chamfered portion and the arc length projection of the reference chamfered portion also includes: When the ratio of the arc length projection of the abnormal chamfered portion to the arc length projection of the reference chamfered portion is equal to 1.1, the grinding thickness is 0.3 mm.

6. The method for recycling unqualified silicon rods according to claim 4, characterized in that: The determining of the grinding thickness according to the arc length projection of the abnormal chamfered portion and the arc length projection of the reference chamfered portion also includes: When the ratio of the arc length projection of the abnormal chamfered portion to the arc length projection of the reference chamfered portion is equal to 1.3, the grinding thickness is 0.7 mm.

7. The method for recycling unqualified silicon rods according to claim 1, characterized in that: After the step of rough grinding and fine grinding the ground silicon rod to obtain the finished square rod, the method further includes: The finished square rod is sliced ​​to obtain a plurality of silicon wafers.

8. The method for recycling unqualified silicon rods according to claim 1, characterized in that: The step of grinding two side wall portions adjacent to the abnormal chamfered portion according to the grinding thickness to obtain a ground silicon rod comprises: According to the grinding thickness, two side wall portions adjacent to the abnormal chamfered portion are ground by a grinding and chamfering integrated machine to obtain a ground silicon rod.

9. The processing method for recycling unqualified silicon rods according to claim 1, characterized in that: The method of rough grinding and fine grinding the ground silicon rod to obtain a finished square rod comprises: The ground silicon rods are coarsely ground and finely ground by a grinding and turning machine to obtain finished square rods.

10. The method for recycling unqualified silicon rods according to claim 1, characterized in that: The surface roughness of the chamfered portion and the side wall portion of the finished square rod is both ≤0.2 μm.

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