Method of manufacturing a multi-layered semiconductor substrate

A method of manufacturing a multi-layered semiconductor substrate comprising:

• a step of preparing a semiconductor substrate composed of single crystals and having a main surface,
• a step of forming a first insulation film on said main surface of said semiconductor substrate,
• a step of forming a first linear opening of a predetermined size reaching said semiconductor substrate at a predetermined position of said first insulation film,
• a step of forming second openings along said first opening to said first insulation film at a position spaced apart at least by 10 .mu.m from the outer edge of said first opening, each of said second openings having an area of 25 .mu.m.sup.2 or less and reaching said semiconductor substrate,
• a step of forming a semiconductor layer composed of non-single crystals on said first insulation film also including the inside of said first and second openings,
• a step of forming a second insulation film on said semiconductor layer,
• a step of supplying heat energy to said semiconductor layer by scanning in a direction from said first opening toward said second openings, and melting said semiconductor layer with said heat energy thereby single crystallizing said semiconductor layer, and
• a step of removing said second insulation film.