US 12,217,969 B2
Silicon dry etching method
Kenta Doi, Kanagawa (JP); Toshiyuki Sakuishi, Kanagawa (JP); Toshiyuki Nakamura, Kanagawa (JP); and Yasuhiro Morikawa, Kanagawa (JP)
Assigned to ULVAC, Inc, Kanagawa (JP)
Filed by ULVAC, Inc., Kanagawa (JP)
Filed on Aug. 3, 2021, as Appl. No. 17/393,208.
Claims priority of application No. 2020-133374 (JP), filed on Aug. 5, 2020.
Prior Publication US 2022/0044938 A1, Feb. 10, 2022
Int. Cl. H01L 21/3065 (2006.01); H01J 37/32 (2006.01); H01L 21/308 (2006.01)
CPC H01L 21/30655 (2013.01) [H01J 37/32091 (2013.01); H01J 37/32816 (2013.01); H01L 21/3085 (2013.01); H01L 21/3086 (2013.01); H01J 2237/332 (2013.01); H01J 2237/334 (2013.01); H01J 2237/335 (2013.01); H01L 21/3081 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A silicon dry etching method, comprising:
preparing a silicon substrate;
forming a mask pattern having an opening pattern on the silicon substrate;
carrying out a deposition process of forming a deposition layer on the silicon substrate in accordance with the mask pattern while introducing a first gas;
carrying out a dry etching process with respect to the silicon substrate in accordance with the mask pattern while introducing a second gas, and thereby forming a recess pattern on a surface of the silicon substrate; and
carrying out an ashing process with respect to the silicon substrate while introducing a third gas, wherein
an adhering product made of the same material as that of the deposition layer adhered to an inner edge of the opening pattern of the mask pattern is removed in the ashing process,
the ashing process is carried out after the dry etching process,
the deposition process and the dry etching process are repetitively carried out,
the ashing process is carried out before the deposition process, and
the silicon dry etching method forms recess patterns having aspect ratios different from each other on the surface of the silicon substrate without a difference in etching rate.