In the process of semiconductor manufacturing, graphite materials are widely used in epitaxy, etching and other processes because of their excellent high temperature performance and processability. However, graphite materials have problems such as high porosity, easy oxidation, and particle release, making it difficult to directly meet the strict cleanliness requirements of semiconductor manufacturing. Silicon carbide (SiC) coating technology can effectively improve the corrosion resistance, high temperature resistance and service life of components by depositing high-purity and dense SiC coatings on the surface of graphite substrates, and has become one of the core processes of semiconductor key consumables.

SiC coating acts as the "outer coat" of graphite base, and its physical and chemical properties directly affect the yield and life of the product. SiC coating has the following advantages: strong corrosion resistance, able to fully wrap the graphite base and avoid being damaged by corrosive gases; high thermal conductivity and high bonding strength with graphite base, ensuring that the coating is not easy to fall off after multiple high temperature and low temperature cycles; good chemical stability, avoiding the failure of the coating in high temperature corrosive atmosphere. In addition, the thermal expansion coefficient of SiC is very different from that of graphite, making it suitable as the preferred material for surface coating of graphite base.

In terms of coating process, the technology of silicon carbide chemical vapor deposition equipment continues to iterate. By using high-precision temperature control system and CFD numerical simulation technology to optimize the equipment structure and process parameters, the purity of coated products can reach 99.9999%, and the main crystal form, crystal direction, hardness and other key technical indicators have reached the domestic advanced level. Vertical silicon carbide coating equipment has completed the process technology iteration, the furnace loading capacity can be increased by 70%, and the coating cycle can be shortened by 33%.

In specific application scenarios, SiC coated graphite bases, SiC coated crystal boats and other products have been widely used in LED chip epitaxy, SiC epitaxy, GaN epitaxy and other fields. Through the self-developed "layered deposition and temperature change deposition" process, it can effectively improve the traditional coating stress, short life and other process difficulties, and achieve a key leap from "domestic replacement" to "supply main force" in the field of SiC coated bases for LED chip epitaxy. A complete independent production line covering graphite purification, precision processing to CVD coating can produce more than 17,000 sets of coating carriers annually.

With the continued maturation of SiC coating technology and the steady release of production capacity, the performance improvement and localization of key semiconductor consumables are expected to further accelerate.