Method for manufacturing silicon carbide semiconductor device

A method for manufacturing a silicon carbide semiconductor device, comprising the steps of:

• preparing a silicon carbide substrate having a main surface covered with a silicon dioxide layer;
• forming a photoresist layer having a pattern on said silicon dioxide layer;
• forming an opening in said silicon dioxide layer through etching with said photoresist layer being used as a mask, so as to expose a portion of said main surface through said opening, a residue resulting from said etching being on said portion of said main surface exposed through said opening;
• removing said residue by plasma etching in which only an inert gas is introduced;
• after the step of removing said residue, forming a trench, which has a side wall surface, in said main surface of said silicon carbide substrate by supplying a reactive gas, under heating, to said silicon carbide substrate having said main surface covered with said silicon dioxide layer having said opening formed therein;
• forming a gate insulating film on said side wall surface of said trench;
• and
• forming a gate electrode on said gate insulating film.