High-precision silicon-based mask plate and processing method thereof

• Main Authors: ZHOU CHENGGANG, WEI YU, HE YIZHAO, SUN JIAN, WANG XIUXIA
• Format: Patent
• Language: Chinese; English
• Published: 19.10.2021
• Subjects: CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION

The invention provides a high-precision silicon-based mask plate and a processing method thereof. According to the high-precision silicon-based mask plate, an SOI sheet is used as a substrate, and a silicon oxide layer in the middle of the SOI sheet can be used as a cut-off layer for front deep silicon etching and can also be used as a cut-off layer for back windowing wet etching, so that fine patterns on the front surface can be protected during back wet etching, and etching liquid is effectively prevented from damaging the patterns on the front surface from the back surface; and meanwhile, the process sequence of dry etching of the front patterns and then wet etching windowing is adopted, so that the uniformity of front deep silicon etching can be improved, and the deviation of the etching depth of different areas of a silicon wafer is within 5%. In addition, the minimum line width of the silicon-based mask plate prepared through the method is 2 microns, the thinnest thickness of the hollow part is 20 micro