Semiconductor device with isolation insulator, interlayer insulation film, and a sidewall coating film

A semiconductor device, comprising:

• a semiconductor substrate having a main surface;
• an isolation insulator formed at the main surface of said semiconductor substrate, having a sidewall and insulating a conductive region;
• a sidewall coating film formed on the sidewall of said isolation insulator;
• and
• an interlayer insulation film formed directly on said isolation insulator and the sidewall coating film, wherein the sidewall coating film has an etching rate different from that of said interlayer insulation film,
• said isolation insulator including
• an upper insulator placed over the main surface of said semiconductor substrate and having said sidewall, wherein the sidewall of said upper insulator is inclined relative to the main surface of said semiconductor substrate,
• a lower insulator connecting to said upper insulator and placed under the main surface of said semiconductor substrate, and
• an upper insulator having its film thickness of at least that of said lower insulator.

A semiconductor device, comprising:

• a semiconductor substrate having a main surface;
• an isolation insulator formed at the main surface of said semiconductor substrate, having a sidewall and isolating a conductive region;
• a sidewall coating film formed on the sidewall of said isolation insulator;
• and
• an interlayer insulation film formed immediately above said isolation insulator and said sidewall coating film, wherein the sidewall coating film has an etching rate different from that of said interlayer insulation film,
• said isolation insulator including an insulation film that is filled in a trench formed at the main surface of said semiconductor substrate and an upper insulator placed over the main surface of said semiconductor substrate and having said sidewall, wherein the sidewall of said upper insulator is inclined relative to the main surface of said semiconductor substrate,
• a lower insulator connecting to said upper insulator and placed under the main surface of said semiconductor substrate.