Can you grind silicon carbide?

Silicon carbide (SiC) has important applications in areas such as power electronics, high-frequency RF devices, and sensors for high-temperature-resistant environments due to its excellent physicochemical properties. However, the slicing operation during SiC wafer processing introduces damages on the surface, which, if left untreated, can expand during the subsequent epitaxial growth process and form epitaxial defects, thus affecting the yield of the device. Therefore, grinding and polishing processes play a crucial role in SiC wafer processing. In the field of silicon carbide (SiC) processing, the technological advancement and industrial development of grinding and polishing equipment is a key factor in improving the quality and efficiency of SiC wafer processing. These equipments originally served in sapphire, crystalline silicon and other industries. With the growing demand for SiC materials in high-performance electronic devices, the corresponding processing technologies and equipments have also been rapidly developed and their applications expanded.

In the grinding process of silicon carbide (SiC) single-crystal substrates, grinding media containing diamond particles are usually used to perform the processing, which is divided into two stages: preliminary grinding and fine grinding. The purpose of the preliminary grinding stage is to improve the efficiency of the process by using larger grain sizes and to remove the tool marks and deterioration layers generated during the multi-wire cutting process, while the fine grinding stage aims at removing the processing damage layer introduced by the preliminary grinding and further refining the surface roughness through the use of smaller grain sizes.

Grinding methods are categorised into single-side and double-side grinding. The double-sided grinding technique is effective in optimising the warpage and flatness of the SiC substrate, and achieves a more homogeneous mechanical effect compared to single-sided grinding by simultaneously processing both sides of the substrate using both upper and lower grinding discs. In single-sided grinding or lapping, the substrate is usually held in place by wax on metal discs, which causes slight deformation of the substrate when machining pressure is applied, which in turn causes the substrate to warp and affect flatness. In contrast, double-sided grinding initially applies pressure to the highest point of the substrate, causing it to deform and gradually flatten. As the highest point is gradually smoothed, the pressure applied to the substrate is gradually reduced, so that the substrate is subjected to a more uniform force during processing, thus greatly reducing the possibility of warpage after the processing pressure is removed. This method not only improves the processing quality of the substrate, but also provides a more desirable basis for the subsequent microelectronics manufacturing process.