A low-loss silicon carbide wafer slicing method

Abstract

The invention relates to the technical field of silicon carbide wafer processing, and specifically to a low-loss silicon carbide wafer slicing method. The invention comprises the following steps: S1, taking a silicon carbide crystal ingot with a thickness of 3.5-6 cm, and cutting it into a silicon carbide crystal column with a thickness of 825-4000 μm by laser cutting; S2, using laser invisible cutting to form cracks on the silicon carbide crystal column obtained in step S1, forming a silicon carbide thin slice with a thickness of 80-200 μm and a silicon carbide thick slice with a thickness of 625-3920 μm on the silicon carbide crystal column, and then applying an adhesive on the silicon carbide thin slice. During slicing, only grinding loss is generated each time, and the loss generated when slicing silicon carbide is smaller. For each 1000 μm silicon carbide crystal column, 6 silicon carbide thin slices can be separated, which can not only separate more silicon carbide thin slices than the traditional multi-wire cutting technology, but also generate less loss, thereby effectively reducing the processing cost of the silicon carbide wafer.

Description

Technical Field

[0001] The invention relates to the technical field of silicon carbide wafer processing, and in particular to a low-loss silicon carbide wafer slicing method. Background Art

[0002] Silicon carbide wafer, also known as silicon carbide single crystal sheet, is a sheet-like single crystal material obtained by cutting, grinding and polishing silicon carbide crystals along a specific crystal direction.

[0003] In the process of slicing silicon carbide crystals, the traditional slicing methods used are multi-wire cutting and laser stripping technology. However, multi-wire cutting is limited by the thickness of silicon carbide crystals and can only cut silicon carbide slices with a thickness of 450-500um. The cutting will produce at least 200μm of loss, which makes it impossible to cut more silicon carbide wafers when slicing silicon carbide crystals, and will also produce excessive losses, increasing the processing cost of silicon carbide wafers. Summary of the invention

[0004] The object of the present invention is to provide a low-loss silicon carbide wafer slicing method to solve the problems raised in the above background technology.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A low-loss silicon carbide wafer slicing method, characterized by comprising the following steps:

[0007] S1. Take a silicon carbide ingot with a thickness of 3.5-6 cm and cut it into silicon carbide crystal columns with a thickness of 825-4000 μm by laser cutting;

[0008] S2. The silicon carbide crystal column obtained in step S1 is cut by invisible laser cutting to form cracks on the silicon carbide, and a silicon carbide thin sheet with a thickness of 80-200 μm and a silicon carbide thick sheet with a thickness of 625-3920 μm are formed on the silicon carbide crystal column, and then an adhesive is applied on the silicon carbide thin sheet, and then a glass carrier is taken, and a nitride-oxide silicone film is applied on the glass carrier to form a release layer, and then the glass carrier is bonded to the top of the silicon carbide thin sheet by forming a bonding layer through the combination of the release layer on the glass carrier and the adhesive on the silicon carbide thin sheet;

[0009] S3, heating the lower side of the silicon carbide thick sheet, flipping the silicon carbide thin sheet and the silicon carbide thick sheet after heating, quickly flipping the glass carrier to the lower side, and then quickly cooling the glass carrier from the lower side, and finally flipping the silicon carbide thin sheet and the silicon carbide thick sheet again, and then using a suction cup to absorb the glass carrier from the upper side of the glass carrier, driving the glass carrier to move upward, and peeling the silicon carbide thin sheet from the silicon carbide thick sheet;

[0010] S4, obtaining a silicon carbide thin sheet with a thickness of 80-200 μm and a silicon carbide thick sheet with a thickness of 625-3920 μm, grinding and polishing the silicon carbide thick sheet; then grinding and polishing the cross section of the silicon carbide thin sheet with a thickness of 80-200 μm to form a silicon carbide thin sheet with both sides being flat and a thickness of 55-175 μm;

[0011] S5, using the silicon carbide thick slice obtained in step S4 as a new silicon carbide crystal column, and returning to step S2 n times repeatedly, separating n silicon carbide thin slices with a thickness of 80-200 μm, 1≤n≤38, until the thickness of the silicon carbide thick slice is 160-500 μm;

[0012] S6, using laser invisible cutting to form cracks on the silicon carbide thick sheet obtained in step S5, so that the silicon carbide thick sheet is formed into two silicon carbide thin sheets with a thickness of 80-200 μm, and then bonding two glass carriers on the surfaces of the two silicon carbide thin sheets by an adhesive;

[0013] S7. Heat the surface of one of the glass carriers, then cool it quickly, and finally use a suction cup to adsorb the upper glass carrier to separate the two silicon carbide slices to form two independent silicon carbide slices with a thickness of 80-200 μm. Finally, grind the cross section of the silicon carbide slice with a thickness of 80-200 μm obtained in step S6 to form two silicon carbide slices with a thickness of 55-175 μm.

[0014] Preferably, in step S1, when performing laser stealth cutting, the laser pulses act equidistantly to form equidistant damage to form a modified layer inside the silicon carbide crystal column, so that the molecular bonds of the material at the modified layer position are destroyed, and the connection of the silicon carbide crystal column becomes fragile and easy to separate.

[0015] Preferably, in step S3, the silicon carbide thin slice is heated from below by heat medium contact heat conduction, and cooled from below the glass carrier by coolant contact conduction. After heating and cooling, the connection between the silicon carbide thin slice and the silicon carbide thick slice is completely disconnected.

[0016] Preferably, in step S3, when cooling is performed from below the glass carrier, a cooling plate is used to support the wafer and the glass carrier, a supporting film frame is used to support the cooling plate, and dry ice is placed in the supporting film frame.

[0017] Preferably, in the step S4, when grinding the cross section of the silicon carbide thick slice, a loss of 25 μm is generated during grinding.

[0018] Preferably, in steps S4 and S7, the obtained silicon carbide slice with a thickness of 55-175 μm is debonded by UV light, and then the glass carrier is removed from the silicon carbide slice. Then, the silicon carbide slice is cleaned to remove the adhesive, thereby obtaining a silicon carbide slice.

[0019] Preferably, in step S6, the process of bonding two glass carriers on the surfaces of two silicon carbide thin sheets by adhesive is as follows: first apply adhesive on one of the glass carriers and one of the silicon carbide thin sheets, then bond one side of the glass carrier with adhesive to one side of the silicon carbide thin sheet with adhesive, flip the glass carrier and the silicon carbide thin sheet, then apply adhesive on another glass carrier and another surface of the silicon carbide thin sheet, and then bond one side of the glass carrier with adhesive to one side of the silicon carbide thin sheet with adhesive, so that both surfaces of the silicon carbide thin sheets are bonded with glass carriers.

[0020] Preferably, in the step S1, laser cutting generates a loss of 300 μm, and the number of silicon carbide wafers obtained by cutting is 8-53.

[0021] Beneficial effects of the present invention:

[0022] First, by bonding a glass carrier plate to the cut silicon carbide slice, it is convenient to peel off the silicon carbide slice on the glass carrier plate with a suction cup, thereby avoiding damage to the silicon carbide slice when peeling off the silicon carbide slice. When the silicon carbide slice is polished, the glass carrier plate supports the silicon carbide slice, which is more convenient for polishing and cleaning the silicon carbide slice.

[0023] Second, when slicing, only grinding loss is generated each time, and the loss generated when slicing silicon carbide is even smaller. For every 1000μm silicon carbide crystal column, 6 silicon carbide slices can be separated. Compared with the traditional multi-wire cutting technology, it can not only separate more silicon carbide slices, but also generate less loss, effectively reducing the processing cost of silicon carbide wafers. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 is a process flow chart of step S1 in the present invention;

[0026] Figure 2 is a process flow chart of step S2 in the present invention;

[0027] Figure 3is a process flow chart of step S3 in the present invention;

[0028] Figure 4 is a process flow chart of step S4 in the present invention;

[0029] Figure 5 is a process flow chart of step S5 in the present invention;

[0030] Figure 6 is a process flow chart of step S6 in the present invention;

[0031] Figure 7 is a process flow chart of step S7 in the present invention;

[0032] Figure 8 yes Figure 3 A schematic diagram of the structure of the top view of the middle bearing membrane frame;

[0033] Fig. 9 yes Figure 8 A schematic diagram of the structure of the bottom part of the middle bearing membrane frame;

[0034] Fig.10 yes Fig. 9 Schematic diagram of the state when the middle load-bearing membrane frame and cooling plate are removed. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] A low-loss silicon carbide wafer slicing method comprises the following steps:

[0038] S1. Take a 4 cm thick silicon carbide ingot and cut it into 31 1000 μm thick silicon carbide crystal columns by laser cutting. The number of cuttings is 30, and each cutting generates a loss of 300 μm.

[0039] S2. The silicon carbide crystal column obtained in step S1 is cut by invisible laser cutting to form cracks on the silicon carbide, and a silicon carbide thin sheet with a thickness of 150 μm and a silicon carbide thick sheet with a thickness of 850 μm are formed on the silicon carbide crystal column. Then, an adhesive is applied on the silicon carbide thin sheet. Then, a glass carrier is taken, and a nitride-oxide silicone film is applied on the glass carrier to form a release layer. Then, the release layer on the glass carrier and the adhesive on the silicon carbide thin sheet are combined to form a bonding layer to bond the glass carrier to the top of the silicon carbide thin sheet.

[0040] S3, heating the lower side of the silicon carbide thick sheet, flipping the silicon carbide thin sheet and the silicon carbide thick sheet after heating, quickly rotating the glass carrier plate to the lower side, and then quickly cooling the glass carrier plate from the lower side, and finally flipping the silicon carbide thin sheet and the silicon carbide thick sheet again, and then using a suction cup to absorb the glass carrier plate from the upper side of the glass carrier plate, driving the glass carrier plate to move upward, and peeling the silicon carbide thin sheet from the silicon carbide thick sheet;

[0041] S4, grinding the cross section of the silicon carbide thick slice, flattening the silicon carbide thick slice, generating a loss of 25 μm, obtaining a silicon carbide thin slice with a thickness of 150 μm and a silicon carbide thick slice with a thickness of 825 μm, and then grinding the cross section of the silicon carbide thin slice with a thickness of 150 μm using the QCB technology to form a silicon carbide thin slice with both sides being flat and a thickness of 100 μm;

[0042] S5, using the silicon carbide thick slice obtained in step S4 as a new silicon carbide crystal column, and returning to step S2 three times to separate three silicon carbide thin slices with a thickness of 100 μm and one silicon carbide thick slice with a thickness of 300 μm;

[0043] S6, using laser invisible cutting to form cracks on the silicon carbide thick sheet obtained in step S5, so that the silicon carbide thick sheet is formed into two silicon carbide thin sheets with a thickness of 150 μm, and then two glass carriers are bonded to the surfaces of the two silicon carbide thin sheets by an adhesive;

[0044] S7. Heat the surface of one of the glass carriers, then cool it quickly, and finally use a suction cup to adsorb the upper glass carrier to separate the two silicon carbide slices to form two independent silicon carbide slices with a thickness of 150 μm. Finally, grind the cross section of the silicon carbide slice with a thickness of 150 μm obtained in step S6 to form two silicon carbide slices with a thickness of 100 μm.

[0045] In summary, for each silicon carbide wafer with a thickness of 1000 μm, in Example 1, in steps S4, S5 and S7, a total of six silicon carbide slices with a thickness of 100 μm are obtained, and 31 silicon carbide wafers with a thickness of 1000 μm can obtain a total of 186 silicon carbide slices with a thickness of 100 μm.

[0046] In step S3, when cooling is performed from below the glass carrier, a cooling plate is used to support the wafer and the glass carrier, a supporting film frame is used to support the cooling plate, and dry ice is placed in the supporting film frame.

[0047] like Figure 8 , Fig. 9 and Fig.10The cooling plate is connected to a cooling system to achieve circulating cooling. The cooling system includes a pipeline and a condenser, a drying filter, a capillary tube and a compressor connected by the pipeline. The pipeline passes through the supporting film frame, and the part of the pipeline passing through the supporting film frame is spirally arranged inside the cooling plate.

[0048] Example 2

[0049] A low-loss silicon carbide wafer slicing method comprises the following steps:

[0050] S1. Take a 4cm thick silicon carbide ingot and cut it into 35 825μm thick silicon carbide crystal columns by laser cutting. The number of cuttings is 34 times, and each cutting generates a loss of 300μm.

[0051] S2. The silicon carbide crystal column obtained in step S1 is cut by invisible laser cutting to form cracks on the silicon carbide, and a silicon carbide thin sheet with a thickness of 150 μm and a silicon carbide thick sheet with a thickness of 675 μm are formed on the silicon carbide crystal column, and then an adhesive is applied on the silicon carbide thin sheet, and then a glass carrier is taken, and a nitride-oxide silicone film is applied on the glass carrier to form a release layer, and then the glass carrier is bonded to the top of the silicon carbide thin sheet by forming a bonding layer through the combination of the release layer on the glass carrier and the adhesive on the silicon carbide thin sheet;

[0052] S3, heating the lower side of the silicon carbide thick sheet, flipping the silicon carbide thin sheet and the silicon carbide thick sheet after heating, quickly rotating the glass carrier plate to the lower side, and then quickly cooling the glass carrier plate from the lower side, and finally flipping the silicon carbide thin sheet and the silicon carbide thick sheet again, and then using a suction cup to absorb the glass carrier plate from the upper side of the glass carrier plate, driving the glass carrier plate to move upward, and peeling the silicon carbide thin sheet from the silicon carbide thick sheet;

[0053] S4, grinding the cross section of the silicon carbide thick slice, flattening the silicon carbide thick slice, generating a loss of 25 μm, obtaining a silicon carbide thin slice with a thickness of 150 μm and a silicon carbide thick slice with a thickness of 650 μm, and then grinding the cross section of the silicon carbide thin slice with a thickness of 150 μm using the QCB technology to form a silicon carbide thin slice with both sides being flat and a thickness of 100 μm;

[0054] S5, using the silicon carbide thick slice obtained in step S4 as a new silicon carbide crystal column, and returning to step S2 twice to separate two silicon carbide thin slices with a thickness of 100 μm and one silicon carbide thick slice with a thickness of 300 μm;

[0055] S6, using laser invisible cutting to form cracks on the silicon carbide thick sheet obtained in step S5, so that the silicon carbide thick sheet is formed into two silicon carbide thin sheets with a thickness of 150 μm, and then two glass carriers are bonded to the surfaces of the two silicon carbide thin sheets by an adhesive;

[0056] S7. Heat the surface of one of the glass carriers, then cool it quickly, and finally use a suction cup to adsorb the upper glass carrier to separate the two silicon carbide slices to form two independent silicon carbide slices with a thickness of 150 μm. Finally, grind the cross section of the silicon carbide slice with a thickness of 150 μm obtained in step S6 to form two silicon carbide slices with a thickness of 100 μm.

[0057] In summary, for each crystal column with a thickness of 825 μm, in Example 2, in steps S4, S5 and S7, a total of five silicon carbide slices with a thickness of 100 μm are obtained, and 35 silicon carbide wafers with a thickness of 1000 μm can obtain a total of 175 silicon carbide slices with a thickness of 100 μm.

[0058] Example 3

[0059] A low-loss silicon carbide wafer slicing method comprises the following steps:

[0060] S1. Take a 4cm thick silicon carbide ingot and cut it into 24 1375μm thick silicon carbide crystal columns by laser cutting. The number of cuttings is 23 times, and each cutting generates a loss of 300μm.

[0061] S2. The silicon carbide crystal column obtained in step S1 is cut by invisible laser cutting to form cracks on the silicon carbide, and a silicon carbide thin sheet with a thickness of 200 μm and a silicon carbide thick sheet with a thickness of 1175 μm are formed on the silicon carbide crystal column, and then an adhesive is applied on the silicon carbide thin sheet, and then a glass carrier is taken, and a nitride-oxide silicone film is applied on the glass carrier to form a release layer, and then the glass carrier is bonded to the top of the silicon carbide thin sheet by forming a bonding layer through the combination of the release layer on the glass carrier and the adhesive on the silicon carbide thin sheet;

[0062] S3, heating the lower side of the silicon carbide thick sheet, flipping the silicon carbide thin sheet and the silicon carbide thick sheet after heating, quickly rotating the glass carrier plate to the lower side, and then quickly cooling the glass carrier plate from the lower side, and finally flipping the silicon carbide thin sheet and the silicon carbide thick sheet again, and then using a suction cup to absorb the glass carrier plate from the upper side of the glass carrier plate, driving the glass carrier plate to move upward, and peeling the silicon carbide thin sheet from the silicon carbide thick sheet;

[0063] S4, grinding the cross section of the silicon carbide thick slice, flattening the silicon carbide thick slice, generating a loss of 25 μm, obtaining a silicon carbide thin slice with a thickness of 200 μm and a silicon carbide thick slice with a thickness of 1150 μm, and then grinding the cross section of the silicon carbide thin slice with a thickness of 150 μm using the QCB technology to form a silicon carbide thin slice with both sides being flat and a thickness of 100 μm;

[0064] S5, using the silicon carbide thick slice obtained in step S4 as a new silicon carbide crystal column, and returning to step S2 three times to separate three silicon carbide thin slices with a thickness of 200 μm and one silicon carbide thick slice with a thickness of 475 μm;

[0065] S6, using laser invisible cutting to form cracks on the silicon carbide thick sheet obtained in step S5, so that the silicon carbide thick sheet is formed into two silicon carbide thin sheets with thicknesses of 250 μm and 225 μm, and then two glass carriers are bonded to the surfaces of the two silicon carbide thin sheets by an adhesive;

[0066] S7. Heat the surface of one of the glass carriers, then cool it quickly, and finally use a suction cup to adsorb the upper glass carrier to separate the two silicon carbide slices to form silicon carbide slices with a thickness of 250 μm and 225 μm. Finally, grind the cross-section of the silicon carbide slices with a thickness of 250 μm and 225 μm obtained in step S6 to form two silicon carbide slices with a thickness of 100 μm.

[0067] In summary, for each crystal column with a thickness of 1375 μm, in Example 3, in steps S4, S5 and S7, a total of 6 silicon carbide slices with a thickness of 100 μm are obtained, and 24 silicon carbide wafers with a thickness of 1000 μm can obtain a total of 144 silicon carbide slices with a thickness of 100 μm.

[0068] Example 4

[0069] A low-loss silicon carbide wafer slicing method comprises the following steps:

[0070] S1. Take a 4cm thick silicon carbide ingot and cut it into 35 850μm thick silicon carbide crystal columns by laser cutting. The number of cuttings is 34 times, and each cutting generates a loss of 300μm.

[0071] S2. The silicon carbide crystal column obtained in step S1 is cut by invisible laser cutting to form cracks on the silicon carbide, and a silicon carbide thin sheet with a thickness of 200 μm and a silicon carbide thick sheet with a thickness of 650 μm are formed on the silicon carbide crystal column. Then, an adhesive is applied on the silicon carbide thin sheet. Then, a glass carrier is taken, and a nitride-oxide silicone film is applied on the glass carrier to form a release layer. Then, the release layer on the glass carrier and the adhesive on the silicon carbide thin sheet are combined to form a bonding layer to bond the glass carrier to the top of the silicon carbide thin sheet.

[0072] S3, heating the lower side of the silicon carbide thick sheet, flipping the silicon carbide thin sheet and the silicon carbide thick sheet after heating, quickly rotating the glass carrier plate to the lower side, and then quickly cooling the glass carrier plate from the lower side, and finally flipping the silicon carbide thin sheet and the silicon carbide thick sheet again, and then using a suction cup to absorb the glass carrier plate from the upper side of the glass carrier plate, driving the glass carrier plate to move upward, and peeling the silicon carbide thin sheet from the silicon carbide thick sheet;

[0073] S4, grinding the cross section of the silicon carbide thick slice, flattening the silicon carbide thick slice, generating a loss of 25 μm, obtaining a silicon carbide thin slice with a thickness of 200 μm and a silicon carbide thick slice with a thickness of 625 μm, and then grinding the cross section of the silicon carbide thin slice with a thickness of 150 μm by using the QCB technology, to form a silicon carbide thin slice with both sides being flat and a thickness of 100 μm;

[0074] S5, using the silicon carbide thick slice obtained in step S4 as a new silicon carbide crystal column, and returning to step S2 once to separate a silicon carbide thin slice with a thickness of 100 μm and a silicon carbide thick slice with a thickness of 400 μm;

[0075] S6, using laser invisible cutting to form cracks on the silicon carbide thick sheet obtained in step S5, so that the silicon carbide thick sheet is formed into two silicon carbide thin sheets with a thickness of 200 μm, and then bonding two glass carriers on the surfaces of the two silicon carbide thin sheets by an adhesive;

[0076] S7. Heat the surface of one of the glass carriers, then cool it quickly, and finally use a suction cup to adsorb the upper glass carrier to separate the two silicon carbide slices to form two silicon carbide slices with a thickness of 200 μm. Finally, grind the cross section of the silicon carbide slice with a thickness of 200 μm obtained in step S6 to form two silicon carbide slices with a thickness of 100 μm.

[0077] In summary, for each crystal column with a thickness of 825 μm, in Example 3, in steps S4, S5 and S7, a total of four silicon carbide slices with a thickness of 100 μm are obtained, and 35 silicon carbide wafers with a thickness of 1000 μm can obtain a total of 140 silicon carbide slices with a thickness of 100 μm.

[0078] For the 100 μm silicon carbide wafer slices prepared in Examples 1-4, for the convenience of comparison, the data of all Examples were normalized based on the data of Example 1 to obtain the following Table 1.

[0079] Table 1

[0080]

[0081] It can be seen from the above table that, compared with Examples 2-4, Example 1 provided by the present invention can obtain more silicon carbide slices, so the low-loss silicon carbide wafer slicing method in Example 1 of the present invention is a preferred embodiment of the present invention.

[0082] Compared with the related art, the low-loss silicon carbide wafer slicing method provided by the present invention has the following beneficial effects:

[0083] By bonding a glass carrier plate to the cut silicon carbide slice, it is convenient to peel off the silicon carbide slice on the glass carrier plate by using a suction cup, thereby avoiding damage to the silicon carbide slice when peeling off the silicon carbide slice. When the silicon carbide slice is polished, the glass carrier plate supports the silicon carbide slice, which makes it more convenient to polish and clean the silicon carbide slice.

[0084] When slicing, only grinding loss is generated each time, and the loss generated when slicing silicon carbide is even smaller. For every 1000μm silicon carbide crystal column, 6 silicon carbide slices can be separated. Compared with traditional multi-wire cutting technology, it can not only separate more silicon carbide slices, but also generate less loss, effectively reducing the processing cost of silicon carbide wafers.

[0085] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A low-loss silicon carbide wafer slicing method, characterized in that: The following steps are involved: S1. Take a silicon carbide ingot with a thickness of 3.5-6 cm and cut it into silicon carbide crystal columns with a thickness of 825-4000 μm by laser cutting; S2. The silicon carbide crystal column obtained in step S1 is cut by invisible laser cutting to form cracks on the silicon carbide, and a silicon carbide thin sheet with a thickness of 80-200 μm and a silicon carbide thick sheet with a thickness of 625-3920 μm are formed on the silicon carbide crystal column, and then an adhesive is applied on the silicon carbide thin sheet, and then a glass carrier is taken, and a nitride silica gel film is applied on the glass carrier to form a release layer, and then the glass carrier is bonded to the top of the silicon carbide thin sheet by forming a bonding layer through the combination of the release layer on the glass carrier and the adhesive on the silicon carbide thin sheet; S3, heating the lower side of the silicon carbide thick sheet, flipping the silicon carbide thin sheet and the silicon carbide thick sheet after heating, quickly flipping the glass carrier to the lower side, and then quickly cooling the glass carrier from the lower side, and finally flipping the silicon carbide thin sheet and the silicon carbide thick sheet again, and then using a suction cup to absorb the glass carrier from the upper side of the glass carrier, driving the glass carrier to move upward, and peeling the silicon carbide thin sheet from the silicon carbide thick sheet; S4, obtaining a silicon carbide thin sheet with a thickness of 80-200 μm and a silicon carbide thick sheet with a thickness of 625-3920 μm, grinding and polishing the silicon carbide thick sheet; then grinding and polishing the cross section of the silicon carbide thin sheet with a thickness of 80-200 μm to form a silicon carbide thin sheet with both sides being flat and a thickness of 55-175 μm; S5, using the silicon carbide thick slice obtained in step S4 as a new silicon carbide crystal column, and returning to step S2 n times repeatedly, separating n silicon carbide thin slices with a thickness of 80-200 μm, 1≤n≤38, until the thickness of the silicon carbide thick slice is 160-500 μm; S6, using laser invisible cutting to form cracks on the silicon carbide thick sheet obtained in step S5, so that the silicon carbide thick sheet is formed into two silicon carbide thin sheets with a thickness of 80-200 μm, and then bonding two glass carriers on the surfaces of the two silicon carbide thin sheets by an adhesive; S7. Heat the surface of one of the glass carriers, then cool it quickly, and finally use a suction cup to adsorb the upper glass carrier to separate the two silicon carbide slices to form two independent silicon carbide slices with a thickness of 80-200 μm. Finally, grind the cross section of the silicon carbide slice with a thickness of 80-200 μm obtained in step S6 to form two silicon carbide slices with a thickness of 55-175 μm.

2. A low-loss silicon carbide wafer slicing method according to claim 1, characterized in that: In step S1, when performing laser stealth cutting, the laser pulses act equidistantly to form equidistant damage to form a modified layer inside the silicon carbide crystal column, so that the molecular bonds of the material at the modified layer position are destroyed, and the connection of the silicon carbide crystal column becomes fragile and easy to separate.

3. A low-loss silicon carbide wafer slicing method according to claim 1, characterized in that: In step S3, the silicon carbide thin slice is heated from below by heat medium contact heat conduction, and cooled from below the glass carrier by coolant contact conduction. After heating and cooling, the connection between the silicon carbide thin slice and the silicon carbide thick slice is completely disconnected.

4. A low-loss silicon carbide wafer slicing method according to claim 3, characterized in that: In step S3, when cooling is performed from below the glass carrier, a cooling plate is used to support the wafer and the glass carrier, a supporting film frame is used to support the cooling plate, and dry ice is placed in the supporting film frame.

5. A low-loss silicon carbide wafer slicing method according to claim 1, characterized in that: In the step S4, when the cross section of the silicon carbide thick slice is ground, a loss of 25 μm is generated during the grinding.

6. A low-loss silicon carbide wafer slicing method according to claim 1, characterized in that: In the steps S4 and S7, the obtained silicon carbide slice with a thickness of 55-175 μm is debonded by UV light, and then the glass carrier is removed from the silicon carbide slice. Then, the silicon carbide slice is cleaned to remove the adhesive, thereby obtaining a silicon carbide slice.

7. A low-loss silicon carbide wafer slicing method according to claim 1, characterized in that: In step S6, the process of bonding two glass carriers on the surfaces of two silicon carbide thin sheets by adhesive is as follows: firstly, applying adhesive on one of the glass carriers and one of the silicon carbide thin sheets, and then bonding the adhesive side of the glass carrier to the adhesive side of the silicon carbide thin sheet, flipping the glass carrier and the silicon carbide thin sheet, and then applying adhesive on the other glass carrier and the other silicon carbide thin sheet, and then bonding the adhesive side of the glass carrier to the adhesive side of the silicon carbide thin sheet, so that both surfaces of the silicon carbide thin sheets are bonded with glass carriers.

8. A low-loss silicon carbide wafer slicing method according to claim 1, characterized in that: In the step S1, a loss of 300 μm is generated when diamond wire cutting is used, and the number of silicon carbide wafers obtained by cutting is 8-53.

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