Negative resist composition comprising base polymer having epoxy ring and Si-containing crosslinker and patterning method for semiconductor device using the same

A method for forming patterns for a semiconductor device, comprising:

• forming a first resist layer on a target layer to be etched on a semiconductor substrate;
• forming a second resist layer by coating the first resist layer with a negative resist composition, wherein the negative resist composition comprises an alkali-soluble base polymer having an epoxy ring substituent, a silicon-containing crosslinker having multiple hydroxy groups, and a photoacid generator;
• pre-baking the second resist layer;
• exposing the second resist layer;
• performing post-exposure baking on the exposed second resist layer;
• developing the exposed second resist layer to form a second resist layer pattern;
• etching the first resist layer using the second resist layer pattern as an etching mask to form a first resist layer pattern;
• and
• etching the target layer using the first resist layer pattern as an etching mask.