| 摘要 |
PROBLEM TO BE SOLVED: To prevent a material from being sputtered on a lower substrate from a mask and to form round corner sections in a trench by using a mask having Mohs's hardness higher than a specific value as the mask. SOLUTION: At the time of etching a silicon carbide substrate 11, a mask layer 12 is formed by applying a material having 4 Mohs's hardness to the surface of the substrate. Then, after the lower areas 13 of the substrate 11 are exposed by patterning the mask layer 12, the areas 13 are etched with plasma. For example, a platinum layer 12 is applied to the upper surface of the substrate 11 and openings 13 through which the areas to be etched of the substrate 11 are exposed are formed by pattering the layer 12. When the substrate 11 is subjected to anisotropic etching by using a plasma agent of oxygen and sulfur hexafluoride, trenches 17 having round corner sections 18 are formed. After the trenches 17 are formed, the platinum used for forming the layer 12 is removed by etching off the platinum with aqua regia.
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