A resist composition is provided comprising a base polymer and a quencher comprising a cyclic ammonium salt having a fluorinated saturated hydrocarbyl group or fluorinated aryl group. The resist composition has a high sensitivity and forms a pattern with improved LWR or CDU, independent of whether it is of positive or negative tone.

A resist composition is provided comprising a base polymer and a quencher comprising a cyclic ammonium salt having a fluorinated saturated hydrocarbyl group or fluorinated aryl group. The resist composition has a high sensitivity and forms a pattern with improved LWR or CDU, independent of whether it is of positive or negative tone.

A resist composition is provided comprising a base polymer and a quencher comprising a cyclic ammonium salt having a fluorinated saturated hydrocarbyl group or fluorinated aryl group. The resist composition has a high sensitivity and forms a pattern with improved LWR or CDU, independent of whether it is of positive or negative tone.

A resist composition is provided comprising a base polymer and a quencher comprising a cyclic ammonium salt having a fluorinated saturated hydrocarbyl group or fluorinated aryl group. The resist composition has a high sensitivity and forms a pattern with improved LWR or CDU, independent of whether it is of positive or negative tone.

A multi-branched cationic phosphonium salt is provided. The multi-branched cationic phosphonium salt has a structure represented by formula (I):

{Z[P.sup.+(R.sup.1)(R.sup.2)(R.sup.3)].sub.n}(X.sup.).sub.n(I) wherein each of R.sup.1, R.sup.2, and R.sup.3 is independently a linear or branched C.sub.1C.sub.10 alkyl group, X.sup. is an organic or inorganic anion, and Z has a structure represented by Formula (IIb) or Formula (IIc):

##STR00001## wherein a is an integer of 115. In Formulas (IIb) and (IIc), Z is connected to [P.sup.+(R.sup.1)(R.sup.2)(R.sup.3)] at the position marked by an asterisk (*), and n is an integer of 34.

A multi-branched cationic phosphonium salt is provided. The multi-branched cationic phosphonium salt has a structure represented by formula (I):

{Z[P.sup.+(R.sup.1)(R.sup.2)(R.sup.3)].sub.n}(X.sup.).sub.n(I) wherein each of R.sup.1, R.sup.2, and R.sup.3 is independently a linear or branched C.sub.1C.sub.10 alkyl group, X.sup. is an organic or inorganic anion, and Z has a structure represented by Formula (IIb) or Formula (IIc):

##STR00001## wherein a is an integer of 115. In Formulas (IIb) and (IIc), Z is connected to [P.sup.+(R.sup.1)(R.sup.2)(R.sup.3)] at the position marked by an asterisk (*), and n is an integer of 34.

Provided is a production method whereby corresponding carboxylic acid anhydrides and carboxylic acid esters can be obtained at high yield from various carboxylic acids even without a solvent and near room temperature. A method for producing a carboxylic acid anhydride represented by formula (II), the method comprising reacting a compound represented by formula (I) and a carboxylic acid in the presence of a Group II metal compound having an ionic ligand containing an oxygen atom. A method for producing a carboxylic acid ester, the method comprising reacting a carboxylic acid anhydride produced by the aforementioned method and an alcohol. In formula (I), R.sup.1 represents a C.sub.1-20 hydrocarbon group. In formula (II), R.sup.2 represents a C.sub.1-20 hydrocarbon group.

Provided is a production method whereby corresponding carboxylic acid anhydrides and carboxylic acid esters can be obtained at high yield from various carboxylic acids even without a solvent and near room temperature. A method for producing a carboxylic acid anhydride represented by formula (II), the method comprising reacting a compound represented by formula (I) and a carboxylic acid in the presence of a Group II metal compound having an ionic ligand containing an oxygen atom. A method for producing a carboxylic acid ester, the method comprising reacting a carboxylic acid anhydride produced by the aforementioned method and an alcohol. In formula (I), R.sup.1 represents a C.sub.1-20 hydrocarbon group. In formula (II), R.sup.2 represents a C.sub.1-20 hydrocarbon group.

Provided is a production method whereby corresponding carboxylic acid anhydrides and carboxylic acid esters can be obtained at high yield from various carboxylic acids even without a solvent and near room temperature. A method for producing a carboxylic acid anhydride represented by formula (II), the method comprising reacting a compound represented by formula (I) and a carboxylic acid in the presence of a Group II metal compound having an ionic ligand containing an oxygen atom. A method for producing a carboxylic acid ester, the method comprising reacting a carboxylic acid anhydride produced by the aforementioned method and an alcohol. In formula (I), R.sup.1 represents a C.sub.1-20 hydrocarbon group. In formula (II), R.sup.2 represents a C.sub.1-20 hydrocarbon group.

Provided is a production method whereby corresponding carboxylic acid anhydrides and carboxylic acid esters can be obtained at high yield from various carboxylic acids even without a solvent and near room temperature. A method for producing a carboxylic acid anhydride represented by formula (II), the method comprising reacting a compound represented by formula (I) and a carboxylic acid in the presence of a Group II metal compound having an ionic ligand containing an oxygen atom. A method for producing a carboxylic acid ester, the method comprising reacting a carboxylic acid anhydride produced by the aforementioned method and an alcohol. In formula (I), R.sup.1 represents a C.sub.1-20 hydrocarbon group. In formula (II), R.sup.2 represents a C.sub.1-20 hydrocarbon group.