Abstract: A polymer containing a structural unit including an aromatic hydroxy group bonded to a main chain, where the aromatic hydroxy group is protected by an acid-labile group represented by the following formula (ALU-1) and is deprotected by action of an acid to become alkali-soluble. This provides: a polymer that makes it possible to form a resist film with which it is possible to form a pattern having extremely high isolated space resolution, small LER, and excellent rectangularity, effects of development loading and residue defects being suppressed, and the pattern having etching resistance and suppressed pattern collapse in the produced resist pattern; a chemically amplified positive resist composition containing the polymer; a resist patterning process using the chemically amplified positive resist composition; and a mask blank including the chemically amplified positive resist composition.

Abstract: A chemically amplified positive resist composition is provided comprising a polymer comprising units containing a phenolic hydroxy group and units containing a phenolic hydroxy group protected with an acid labile group, in which a carbon atom neighboring the carbon atom to which the phenolic hydroxy group protected with an acid labile group is attached is substituted with a specific group. A resist pattern with a high resolution, reduced LER, rectangularity, minimized influence of develop loading, and few development residue defects can be formed.

Abstract: A chemically amplified positive resist composition comprising (A) a base polymer, (B) a photoacid generator, and (C) a quencher is provided. The base polymer (A) contains a polymer comprising phenolic hydroxy group-containing units, aromatic ring-containing units, and units containing a phenolic hydroxy group protected with an acid labile group. The photoacid generator (B) and the quencher (C) are present in a weight ratio (B)/(C) of less than 3/1. The resist composition exhibits a very high isolated-space resolution and forms a pattern with reduced LER, rectangularity, minimized influences of develop loading and residue defects.

Abstract: The present invention is a sulfonium salt represented by the following formula (1), wherein “p” represents an integer of 1 to 3; R11 represents a hydrocarbyl group having 1 to 20 carbon atoms; Rf represents a fluorine atom or a fluorine-atom-containing C1 to C6 group selected from alkyl, alkoxy, and sulfide; “q” represents an integer of 1 to 4; RALU represents an acid-labile group; “r” represents an integer of 1 to 4; R12 represents a hydrocarbyl group having 1 to 20 carbon atoms; “s” represents an integer of 0 to 4; “t” represents an integer of 0 to 2; Rf and —O—RALU are bonded to adjacent carbon atoms; and X? represents a non-nucleophilic counterion having no polymerizable group.

Abstract: A chemically amplified positive resist composition is provided comprising (A) an acid diffusion-controlling agent in the form of an onium salt compound having a specific phenoxide anion, (B) a polymer comprising specific repeat units and adapted to be decomposed under the action of acid to increase its solubility in alkaline developer, and (C) a photoacid generator. A resist pattern with a high resolution, reduced LER, and improved CDU is formed. Because of minimal defects, the resist pattern can be inspected with light of short wavelength 300-400 nm.