CN-121989120-A - High-flatness silicon carbide crystal bar and preparation method and preparation device thereof

CN121989120ACN 121989120 ACN121989120 ACN 121989120ACN-121989120-A

Abstract

The application relates to a high-flatness silicon carbide crystal bar and a preparation method and a preparation device thereof, and belongs to the field of silicon carbide processing. The high-flatness silicon carbide crystal bar is obtained through grinding, the total thickness change is not more than 18 mu m, and the surface roughness is not more than 30 nm. According to the application, the silicon carbide crystal bar is ground by matching the grinding wheel with the grinding fluid, wherein the diamond is used as an abrasive, so that the grinding efficiency and the grinding effect are effectively improved, and the obtained high-flatness silicon carbide crystal bar has smaller total thickness variation and surface roughness.

Inventors

LIU SHUO
SONG MENG
WANG KAI
MA LIXING
Re Niya
Jin Wanqi

Assignees

山东天岳先进科技股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260105

Claims (10)

1. The high-flatness silicon carbide crystal bar is characterized in that the high-flatness silicon carbide crystal bar is obtained by grinding by a grinding wheel and grinding fluid, the total thickness change of the upper surface and the lower surface of the silicon carbide crystal bar is not more than 18 mu m, and the surface roughness of the upper surface and the lower surface is not more than 30 nm.
2. The high flatness silicon carbide boule of claim 1, wherein the silicon carbide boule comprises a central region and an edge region surrounding the outside of the central region, the central region being a region extending outwardly from the center of the boule to 1/2 diameter; the silicon carbide crystal rod at least meets one of the following conditions: L1-L2 is less than or equal to 5 mu m, and L3-L4 is less than or equal to 5 mu m; R1-R2 is less than or equal to 5nm, and R3-R4 is less than or equal to 5nm; Wherein L1 is the local thickness deviation at any position of the upper surface edge region, L2 is the local thickness deviation at any position of the upper surface center region, L3 is the local thickness deviation at any position of the lower surface edge region, L4 is the local thickness deviation at any position of the lower surface center region, R1 is the surface roughness at any position of the upper surface edge region, R2 is the surface roughness at any position of the upper surface center region, R3 is the surface roughness at any position of the lower surface edge region, and R4 is the surface roughness at any position of the lower surface center region.
3. The high flatness silicon carbide boule of claim 1, wherein the silicon carbide boule comprises, from top to bottom, an upper surface layer region, a middle region, and a lower surface layer region, the upper surface layer region being a region extending 5 μm inward from an upper surface of the silicon carbide boule, the lower surface layer region being a region extending 5 μm inward from a lower surface of the silicon carbide boule, the middle region being a region between the upper surface layer region and the lower surface layer region; the silicon carbide crystal rod at least meets one of the following conditions: The I F1-F2I is less than or equal to 10 arcsec, and |F3-F2| is less than or equal to 10 arcsec; The I T1-T2I is less than or equal to 0.2 cm -1 , and the I T3-T2I is less than or equal to 0.2 cm -1 ; F1 is the half-width of the diffraction peak of the upper surface layer region X-ray diffraction test at (0004), F2 is the half-width of the diffraction peak of the middle region X-ray diffraction test at (0004), F3 is the half-width of the diffraction peak of the lower surface layer region X-ray diffraction test at (0004), T1 is the transverse optical phonon mode peak position of the upper surface layer region measured by raman spectroscopy, T2 is the transverse optical phonon mode peak position of the middle region measured by raman spectroscopy, and T3 is the transverse optical phonon mode peak position of the lower surface layer region measured by raman spectroscopy.
4. A method for producing a high flatness silicon carbide ingot according to any one of claims 1 to 3, comprising the steps of: (1) Grinding the surface of the silicon carbide crystal bar by adopting a grinding wheel, wherein the rotation direction of the grinding wheel is opposite to that of the silicon carbide crystal bar, and spraying grinding fluid at the contact position of the grinding wheel and the silicon carbide crystal bar until the grinding thickness reaches a preset thickness removal value, wherein the spraying flow rate of the grinding fluid is 100-500L/h, and the grinding fluid comprises solid particles, solvents and auxiliaries in a weight ratio of 1 (50-100) (1-5); (2) And (3) polishing the silicon carbide crystal bar in the step (1) to obtain the silicon carbide crystal bar.
5. The method of claim 4, wherein the side of the grinding wheel is tangent to the vertical plane of the center of the silicon carbide crystal rod, and/or The rotating speed of the grinding wheel is not lower than 1000 rpm, and the rotating speed of the silicon carbide crystal bar is not lower than 50 rpm.
6. The method according to claim 5, wherein the grinding wheel has a downward grinding speed of not less than 0.4 μm/s, and the grinding wheel has a mesh number of not more than 30000#.
7. The method according to claim 4, wherein the predetermined thickness-removing value is 1 to 5 mm, and/or The polishing time is 30-120 s.
8. The method of producing according to claim 4, wherein the solid particles include at least one of diamond, boron carbide, and alumina; the solvent comprises water; The auxiliary agent comprises at least one of sodium tripolyphosphate, sodium hexametaphosphate, polyacrylamide and fatty acid polyethylene glycol ester.
9. An apparatus for preparing the high flatness silicon carbide crystal rod according to any one of claims 1 to 3, comprising: the vacuum chuck rotating table is used for vacuum adsorption fixing of the silicon carbide crystal bar and driving the silicon carbide crystal bar to rotate; The grinding fluid spraying mechanism is arranged above the vacuum chuck rotating table and is used for spraying grinding fluid to the surface of the silicon carbide crystal bar; the grinding wheel is arranged above the vacuum chuck rotating table, the side surface of the grinding wheel is tangent to the vertical surface where the circle center of the silicon carbide crystal bar is located, and a rotating shaft is connected above the grinding wheel; The moving mechanism is arranged above the rotating shaft and connected with the rotating shaft, and the moving mechanism is used for driving the grinding wheel to ascend or descend.
10. The apparatus of claim 9, wherein the grinding wheel has a mesh number not greater than 30000#, the rotation shaft is an air-bearing shaft or a mechanical shaft, and/or The diameter of the vacuum chuck rotating table is not smaller than 200 mm.

Description

High-flatness silicon carbide crystal bar and preparation method and preparation device thereof Technical Field The application relates to a high-flatness silicon carbide crystal bar and a preparation method and a preparation device thereof, and belongs to the technical field of silicon carbide processing. Background The disclosure of this background section is only intended to increase the understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art already known to those of ordinary skill in the art. The silicon carbide crystal has excellent electronic and chemical properties, good heat conductivity coefficient, wide band gap, 3 times of forbidden width of silicon, good heat conductivity, 4-5 times of heat conductivity of silicon, 8 times of breakdown voltage of silicon material, high hardness and high temperature resistance. Silicon carbide can be widely applied to the fields of high voltage, high temperature, high power and high frequency electronics, such as high power devices, photoelectric devices, microwave radio frequency devices and the like. The application field of the silicon carbide requires that the silicon carbide has an ultra-smooth, non-damaged and high-surface-quality processing surface, but the silicon carbide has hardness inferior to that of diamond, is relatively brittle and has chemical inertness, so that the silicon carbide has high surface processing difficulty and low processing precision. In the existing processing method of the surface of the silicon carbide crystal bar, a grinding machine is generally adopted to carry out flat grinding operation on the silicon carbide crystal bar. The silicon carbide crystal bar is fixed on a workbench in a wax sticking mode, the resin grinding wheel is in contact with the processing surface of the silicon carbide crystal bar, and the surface of the silicon carbide crystal bar is transversely removed through the unidirectional reciprocating grinding action, so that the surface planarization is achieved. The flat grinding method has long processing time, and generally, the surface material with the thickness of 3mm is removed, and the processing time is 5 hours. And the Total Thickness Variation (TTV) of the processed silicon carbide crystal rod is more than 30 mu m, the surface roughness (Ra) is generally more than 400 nm, and the requirement of a precise device is difficult to meet. In the processing of silicon carbide wafers, there are processing methods using grinding wheels and grinding fluid to obtain silicon carbide wafers with high flatness, and when the method is used for processing silicon carbide crystal rods, the problems that the grinding fluid is difficult to uniformly cover, the grinding heat is difficult to control and the crystal rods are easy to crack exist, so the prior art does not have the method for processing the silicon carbide crystal rods by using the grinding wheels and the grinding fluid. Disclosure of Invention In order to solve the problems, a high-flatness silicon carbide crystal bar, a preparation method and a preparation device thereof are provided. According to the invention, the silicon carbide crystal bar is ground by matching the grinding wheel with the grinding fluid, wherein the diamond is used as an abrasive, so that the grinding efficiency and the grinding effect are effectively improved, and the obtained high-flatness silicon carbide crystal bar has smaller total thickness variation and surface roughness. The invention is realized by the following technical scheme: in a first aspect, the invention provides a high-flatness silicon carbide crystal rod obtained by grinding with a grinding wheel and a grinding fluid, wherein the total thickness variation of the upper surface and the lower surface of the silicon carbide crystal rod is not more than 18 mu m, and the surface roughness of the upper surface and the lower surface is not more than 30 nm. Preferably, the total thickness variation of the upper surface and the lower surface of the silicon carbide crystal bar is not more than 10 mu m, and the surface roughness of the upper surface and the lower surface is not more than 20 nm. Preferably, the high flatness silicon carbide boule has a size of at least 4 inches. Preferably 8 inches or more, and more preferably 12 inches or more. Optionally, the silicon carbide crystal bar comprises a central region and an edge region surrounding the outer side of the central region, wherein the central region is a region extending outwards from the center of the crystal bar to a 1/2 diameter; the silicon carbide crystal rod at least meets one of the following conditions: |L1-L2|≤5μm; |R1-R2|≤5nm; Wherein L1 is a local thickness deviation (LTV) at any position of the upper surface edge region, L2 is a local thickness deviation (LTV) at any position of the upper surface edge region, L3 is a local thickness d