US Patent 11270891 Method for making self-aligned double pattern

The disclosure provides a method for making a self-aligned double pattern, A silicon substrate with a first oxide layer, an amorphous silicon layer and an organic layer, etching the organic layer and the amorphous silicon layer, and covering them with a first silicon nitride layer; remove the first silicon nitride layer in the amorphous silicon pattern, forming first silicon nitride sidewall patterns on the amorphous silicon pattern's sidewalls; removing the amorphous silicon pattern between the first silicon nitride sidewall patterns; defining the morphology of a fin field-effect transistor, form core patterns and covering them with a thin silicon nitride layer; depositing a second oxide layer; defining the fin field-effect transistor's height, and etching back the second oxide layer till the height of the core patterns satisfies the defined fin field-effect transistor height; removing the thin silicon nitride layer, depositing a third oxide layer to cover the core patterns.