The invention comprises a process for preparing mixtures of DEFI and amide taurate (ATA) having excellent yields of ATA and substantial absence of browning of final ATA and DEFI mixtures. The process permits much greater flexibility in ratios of DEFI to ATA. The invention further relates to mixtures prepared by processes of the invention.

Disclosed are a photoacid generator, a photoresist composition including the same, and a method of preparing the photoacid generator. The photoacid generator may include a compound represented by Formula 1:

##STR00001##

wherein, in Formula 1, CY, A1, A2, and B are respectively described in the specification.

Disclosed are a photoacid generator, a photoresist composition including the same, and a method of preparing the photoacid generator. The photoacid generator may include a compound represented by Formula 1:

##STR00001##

wherein, in Formula 1, CY, A1, A2, and B are respectively described in the specification.

A metal-containing onium salt compound suitable for use as a photodegradable base of a resist composition and a resist composition using the metal-containing onium salt compound are provided, the resist composition having excellent sensitivity to ionizing radiation such as extreme ultraviolet (EUV), excellent resolution and focal depth in lithography, and can reduce line width roughness (LWR) in a fine pattern. The onium salt compound including a specific metal is used as the photodegradable base.

A metal-containing onium salt compound suitable for use as a photodegradable base of a resist composition and a resist composition using the metal-containing onium salt compound are provided, the resist composition having excellent sensitivity to ionizing radiation such as extreme ultraviolet (EUV), excellent resolution and focal depth in lithography, and can reduce line width roughness (LWR) in a fine pattern. The onium salt compound including a specific metal is used as the photodegradable base.

Provided is a radiation-sensitive resin composition capable of exhibiting sensitivity and CDU performance at a sufficient level when a next-generation technology is applied, and a pattern formation method. A radiation-sensitive resin composition containing: a radiation-sensitive acid generating resin comprising a repeating unit A having an acid-dissociable group represented by the following formula (1) and a repeating unit B including an organic acid anion moiety and a sulfonium cation moiety containing an aromatic ring structure having a fluorine atom; and a solvent; in the formula (1), R.sup.T is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; R.sup.X is a monovalent hydrocarbon group having 2 to 20 carbon atoms; and Cy represents an alicyclic structure having 3 to 20 ring members and formed together with a carbon atom to which this is bonded.

##STR00001##

A novel onium salt and a resist composition comprising the same as a PAG are provided. When processed by photolithography using KrF or ArF excimer laser, EB or EUV, the resist composition is reduced in acid diffusion and improved in exposure latitude, MEF, and LWR.

A novel onium salt and a resist composition comprising the same as a PAG are provided. When processed by photolithography using KrF or ArF excimer laser, EB or EUV, the resist composition is reduced in acid diffusion and improved in exposure latitude, MEF, and LWR.

Disclosed are a salt represented by formula (I), an acid generator and a resist composition:

##STR00001##

wherein Q.sup.1 and Q.sup.2 each represent a fluorine atom or a perfluoroalkyl group; R.sup.11 and R.sup.12 each represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group; z represents an integer of 0 to 6; X.sup.0 represents *—CO—O—, *—O—CO—, etc.; L.sup.1 represents a single bond or a hydrocarbon group which may have a substituent; Ar represents an aromatic hydrocarbon group which may have a substituent; X.sup.1 represents an oxygen atom or a sulfur atom; R.sup.1 represents a halogen atom or a haloalkyl group; R.sup.2 represents a halogen atom, a hydroxy group, a haloalkyl group or an alkyl group; m1 represents an integer of 1 to 6; m2 represents an integer of 0 to 4; and Z.sup.+ represents an organic cation.

Disclosed are a salt represented by formula (I), an acid generator and a resist composition:

##STR00001##

wherein Q.sup.1 and Q.sup.2 each represent a fluorine atom or a perfluoroalkyl group; R.sup.11 and R.sup.12 each represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group; z represents an integer of 0 to 6; X.sup.1 and X.sup.2 each represent *—CO—O—, *—O—CO—, etc.; L.sup.1 represents a single bond or a hydrocarbon group which may have a substituent; A.sup.1 represents a group having a lactone structure which may have a substituent; L.sup.2 and L.sup.3 each represent a single bond or an alkanediyl group; R.sup.1 represents an iodine atom or a haloalkyl group; R.sup.2 represents a halogen atom, a hydroxy group, a haloalkyl group or an alkyl group; m2 represents an integer of 0 to 4; and Z.sup.+ represents an organic cation.