Method for manufacturing semiconductor base material

A method for manufacturing a semiconductor base material by processing a substrate so that a surface of the substrate has a concave-convex structure, and epitaxially growing a semiconductor layer above the substrate so that the concave-convex structure is buried, the method comprising:

• a step of forming a resist mask on the surface of the substrate by a photolithography process;
• and
• a step of selectively etching the substrate using the resist mask to form the concave-convex structure on the surface of the substrate,
• wherein the step of forming the resist mask comprises an exposure step of repeatedly performing a process of transferring an exposure pattern formed on a transfer mask, onto a resist film formed on the substrate, for each exposure region corresponding to the transfer mask, and
• wherein the transfer mask is obtained by correcting the size of a light shielding pattern positioned in a corresponding manner near a multiple exposure section where the exposure of light to adjacent exposure regions overlap with each other on the resist film, based on an increase in an exposure amount due to multiple exposure.