Patent ID: 7943520

Claim:
A hole pattern forming method that forms a fine hole pattern in a work target layer that is formed on a semiconductor substrate, comprising: forming a three-layer structure by laminating a carbon film layer, an intermediate mask layer, and a photoresist layer in that order on the work target layer; after patterning a hole pattern in the photoresist layer, patterning the hole pattern in the intermediate mask layer with the patterned photoresist layer serving as a mask; forming a sidewall oxide film on exposed portions of the photoresist layer, the intermediate mask layer, and the carbon film layer; forming a sidewall portion that includes the sidewall oxide film on inner wall surfaces of the hole pattern by etching back the sidewall oxide film; and after patterning a fine hole pattern in the carbon film layer with the sidewall portion and the intermediate mask layer serving as a mask, patterning the fine hole pattern in the work target layer with the patterned carbon film layer serving as a mask.