Patterning process

A patterning process, in a patterning process comprising steps of at least:

• forming a single photoresist film on a substrate;
• exposing the photoresist film to a high energy beam;
• developing a photoresist by using a developer so as to form a photoresist pattern;
• and then forming a spacer only on the photoresist pattern sidewall, thereby forming a pattern on the substrate,
• wherein a photoresist film composition to form the photoresist film is a chemically amplified positive resist composition, and a base polymer contained in the photoresist film composition contains repeating unit “a” having one or more adhesion groups selected from a hydroxyl group, a hydroxynaphthyl group, a hydroxyacenaphthyl group, a carboxy group, and a 2,2,2-trifluoro-1-hydroxyethyl group and repeating unit “c” having an acid labile group represented by the following general formula (c1),
• wherein, R15 represents a hydrogen atom or a methyl group, and R16 represents an acid labile group, and
• wherein at least the photoresist pattern having the hardness of 0.4 GPa or more or the Young's modulus of 9.2 GPa or more as a film strength is formed and a pattern is formed on the substrate by forming a silicon oxide film as the spacer on the photoresist pattern sidewall.