| 摘要 |
PROBLEM TO BE SOLVED: To provide a method which can stably etch without adopting the above-mentioned remedy without changing the etching speed even when a basic etchant is used repeatedly when a silicon is anisotropically etched by using the basic etchant. SOLUTION: The method of performing anisotropic etching of the silicon by using an etching apparatus having an etching bath in which the basic etchant is introduced into its interior, making the basic etchant such as TMAH stay in the apparatus and repeatedly using the basic etchant includes the steps of controlling the concentration C (mol/l) of carbonate ion contained in the basic etchant introduced into the etching apparatus within a range of C<SB>0</SB>±0.1 (mol/l) (wherein C is a real number of "0" or more) when the concentration of the carbonate ion included in the initial basic etchant introduced into the etching apparatus is C<SB>0</SB>(mol/l), making the basic etchant stay in the etching apparatus for 72 hours or longer, and using the basic etchant. COPYRIGHT: (C)2006,JPO&NCIPI
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