Quartz is considered an ideal material for etching equipment due to its excellent physical and chemical properties, such as high hardness, wear resistance, stability, and chemical corrosion resistance. Since the main component of quartz is silicon dioxide, the same as silicon wafers, it will not contaminate the wafer during use. In addition, the high light transmittance and good processability of quartz make it a preferred material for the windows and internal components of the etcher.
However, when quartz is exposed to high-energy plasma environments for a long time, it will react with silicon, causing corrosion and blurring of components, which limits its long-term durability in the etcher.
To overcome this problem, aluminum oxide was proposed as an alternative to quartz. Aluminum oxide showed good corrosion resistance for a period of time, but with the widespread application of fluorine-containing plasma, the performance of aluminum oxide gradually failed to meet production needs. The compounds generated by the reaction of fluorine ions with aluminum will deposit and form particulate impurities, which may contaminate the wafer.
Therefore, researchers began to look for new materials, and Y2O3 transparent ceramics attracted attention due to its excellent corrosion resistance in fluorine-containing plasma. Nevertheless, Y2O3 transparent ceramics have poor sintering performance, high production costs, insufficient mechanical properties, and are difficult to process.
As a new type of material, YAG transparent ceramics exhibit similar corrosion resistance to Y2O3, and have higher light transmittance and superior mechanical properties, making them easier to process and becoming a more ideal alternative material.
When selecting materials for etching equipment components, it is necessary to comprehensively consider factors such as the material's corrosion resistance, light transmittance, mechanical properties, and cost. Although quartz, alumina, and YAG transparent ceramics each have their own advantages and disadvantages, YAG transparent ceramics have outstanding comprehensive performance and have become a potential alternative material. With the in-depth study of material properties, it is expected that more advanced etching equipment component materials will appear in the future to meet the growing needs of the semiconductor industry.
