| 摘要 |
PROBLEM TO BE SOLVED: To provide an etching method for a silicon material where the thickness of a silicon oxide film used as a mask material can be reduced. SOLUTION: As an etching liquid used in an etching stage where a recessed part for an ink pressure chamber, a recessed part for an ink reserver or the like are formed, e.g., on a cavity plate in an ink jet head, the one obtained by incorporating calcium, e.g., of≥500 ppb into an alkali solution of KOH or the like is used. When the concentration of calcium increases, the etching rate of a silicon oxide film 32 by the etching liquid is reduced. Since the reduction amount of the silicon oxide film serving as a mask material is small at the time of etching a silicon material, the thickness is reduced. Thus, thermal oxidation treatment time for forming the silicon oxide film can be reduced, and treatment cost therefor can be reduced as well. Since a mask pattern can be formed on the thin silicon oxide film at high precision, the silicon material can be etched with high precision. COPYRIGHT: (C)2005,JPO&NCIPI
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