1. surface cleaning: firstly, clean the surface of silicon carbide wafer to remove pollutants and impurities on the surface. This can be done by solvent cleaning, ultrasonic cleaning or other suitable methods.
2. Rough grinding: Put the wafer into a special grinder, coat grinding particles (such as alumina) and grinding liquid (such as polymethyl methacrylate) on the rotating disk, and grind the surface smoothly through the interaction of rotation and movement.
3. Medium grinding: After rough grinding, the wafer is medium ground to further reduce the surface roughness and improve the flatness. This step usually uses slurry of abrasive particles and smaller particles.
4. Fine grinding: Fine grinding is to obtain a finer surface finish. The wafer is finely ground with smaller abrasive particles and slurry. This step helps to eliminate microscopic defects and surface defects.
5. Polishing: The last step is to polish the wafer with a polishing machine to eliminate the residual traces left in the fine grinding process and further improve the surface quality. Usually, polishing solution (such as silica sol) and polishing cloth or polishing pad are used for polishing.
The above is the general process flow of silicon carbide wafer polishing, and the specific parameters and methods may be different according to the actual application and requirements. In actual operation, it needs to be adjusted and optimized according to factors such as wafer size, requirements and equipment capacity.