Method for creating gray-scale features for dual tone development processes

A method of patterning a substrate using a dual-tone development process, comprising:

• providing a substrate having a layer of radiation-sensitive material on said substrate, wherein said layer of radiation-sensitive material comprises a dual tone photo-resist;
• providing a mask having a dual-tone mask pattern region configured for printing dual-tone features and a half-tone mask pattern region configured for printing half-tone features;
• performing a dual-tone development process by performing one or more exposures of said layer of radiation-sensitive material to one or more patterns of radiation to print said dual-tone features in said dual tone photo-resist with a double pattern in said dual-tone mask pattern region and print half-tone features in said dual tone photo-resist without a double pattern in said half-tone mask pattern region;
• and
• selecting mask properties of said half-tone mask pattern region for use with said dual tone photo-resist such that said dual-tone development process avoids producing pattern defects that include an undesirable void in half-tone features printed by said dual-tone development process.