Method of manufacturing a semiconductor device involving sidewall spacer formation

A method of manufacturing a .mu. wave transistor, comprising the steps of:

• preparing a semiconductor body having a semiconductor layer of a first conductivity type as a collector region, and a semi-conductor layer of a second conductivity type as a base region formed on said semiconductor layer of the first conductivity type;
• forming at least one first insulating layer on said semiconductor layer of the second conductivity type;
• forming a metal first mask layer on said first insulating layer;
• forming a second insulating mask layer on said metal first mask layer;
• forming a resist film on said second insulating layer;
• patterning said resist film to obtain a pattern having openings above an emitter region and a base leading region;
• patterning said second insulating layer, by etching using said patterned resist film as a mask;
• forming a third insulating layer on the resultant structure;
• dry-etching said third insulating layer to be left on at least one side wall of said patterned second insulating layer;
• patterning said metal first mask layer, by etching using the residual third insulating layer and said patterned second insulating layer as masks;
• patterning said first insulating layer, by etching using said patterned metal first mask layer as a mask for forming contact holes for the emitter region and the base leading region;
• forming the emitter region and the base leading region in said semiconductor layer of the second conductivity type;
• and
• forming an emitter electrode and a base electrode electrically contacting said emitter and base leading regions, respectively.

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

• forming at least one first insulating layer on a semiconductor body;
• forming a metal layer on said first insuating layer;
• forming a second insulating layer on said metal layer;
• forming a resist layer on said second insulating layer;
• patterning said resist layer to obtain a pattern;
• etching said second insulating layer, using said patterned resist layer as a mask;
• etching said metal layer, using said etched second insulating layer as a mask;
• and
• etching said first insulating layer, using said etched metal layer as a mask.

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

• preparing a semiconductor body having a semiconductor layer of a first conductivity type and a semiconductor layer of a second conductivity type formed on said semiconductor layer of the first conductivity type;
• forming at least one insulating film on said semiconductor substrate of the second conductivity type;
• forming a first mask layer consisting essentially of a metal on said at least one insulating film;
• forming an insulating second mask layer on said metal first mask layer;
• forming a resist film on said insulating second mask layer;
• patterning said resist film to form a resist;
• patterning said insulating second mask layer by dry etching said insulating second mask layer using said resist as a mask;
• removing said resist;
• forming an insulating coating film on the resultant structure;
• dry etching said insulating coating film to leave the insulating coating film as a residual film on at least one side wall of said patterned insulating second mask layer;
• patterning said metal first mask layer by dry etching said metal first mask layer using said patterned insulating second mask layer and said residual insulating coating film as a mask;
• removing said patterned insulating second mask layer and said residual insulating coating film;
• patterning said at least one insulating film by dry etching said at least one insulating film using said patterned metal first mask layer as a mask;
• removing said patterned metal first mask layer;
• doping an impurity of the first conductivity type to form an emitter region and of the second conductivity type to form a base-leading region, into said semiconductor layer of the second conductivity type, using said patterned at least one insulating film as a mask;
• and
• forming an emitter electrode connected to the emitter region and a base electrode connected to the base leading region.