Micro-structure manufacturing method

A method of manufacturing a micro-structure comprising:

• dry-etching a sacrificial layer provided to a silicon substrate, the sacrificial layer including a buried oxide layer having a cavity formed by the dry-etching, the substrate including a first silicon layer and a second silicon layer, to form structures, the sacrificial layer reacting with etching gas to generate reaction products including H2O, and forming grooves in the second silicon layer corresponding to the cavity to penetrate through the second silicon layer from the upper surface to the cavity in the thickness direction, wherein the dry-etching includes etching the sacrificial layer and removing H2O as one of the reaction products generated through the etching step of the sacrificial layer, wherein the etching and the removing of H2O are repetitively performed, wherein the etching gas comprises a mixture gas of anhydrous HF gas and methanol gas and the sacrificial layer is formed of SiO2, the anhydrous HF gas and the methanol gas (M) and the sacrificial layer reacting according to the following reaction formulas:
• anhydrous HF gas←→HF (adsorbed);
• M←→M (adsorbed);
• 2HF+M→HF2−+MH+;
• SiO2+2HF2−+2MH+SiF4⇑+2H2O⇑+2M⇑.