The present invention is a resist material containing a quencher, where the quencher contains a sulfonium salt of a carboxylic acid bonded to a maleimide group. In a chemically amplified resist material in which an acid is used as a catalyst, it is desired to develop a quencher that makes it possible to reduce LWR of line patterns and critical dimension uniformity (CDU) of hole patterns, and to improve sensitivity. For this purpose, it is necessary to reduce image blurs due to acid diffusion considerably. An object of the present invention is to provide: a resist material having high sensitivity, low LWR, and low CDU in both a positive resist material and a negative resist material; and a patterning process using the same.

The present invention is a resist material containing a quencher, where the quencher contains a sulfonium salt of a carboxylic acid bonded to a maleimide group. In a chemically amplified resist material in which an acid is used as a catalyst, it is desired to develop a quencher that makes it possible to reduce LWR of line patterns and critical dimension uniformity (CDU) of hole patterns, and to improve sensitivity. For this purpose, it is necessary to reduce image blurs due to acid diffusion considerably. An object of the present invention is to provide: a resist material having high sensitivity, low LWR, and low CDU in both a positive resist material and a negative resist material; and a patterning process using the same.

A radiation-sensitive resin composition includes: a polymer which has a first structural unit including a phenolic hydroxyl group, and a second structural unit represented by formula (1); and a radiation-sensitive acid generating agent which has a compound represented by formula (2). R.sup.1 represents a hydrogen atom, or the like; R.sup.2 represents a hydrogen atom or the like; and R.sup.3 represents a divalent monocyclic alicyclic hydrocarbon group having 3 to 12 ring atoms. Ar.sup.1 represents a group obtained by removing (q+1) hydrogen atoms on an aromatic ring from an arene formed by condensation of at least two benzene rings; R.sup.4 represents a monovalent organic group having 1 to 20 carbon atoms; q is an integer of 0 to 7; and R.sup.5 represents a halogen atom, a hydroxy group, a nitro group, or a monovalent organic group having 1 to 20 carbon atoms, or the like.

##STR00001##

A radiation-sensitive resin composition includes: a polymer which has a first structural unit including a phenolic hydroxyl group, and a second structural unit represented by formula (1); and a radiation-sensitive acid generating agent which has a compound represented by formula (2). R.sup.1 represents a hydrogen atom, or the like; R.sup.2 represents a hydrogen atom or the like; and R.sup.3 represents a divalent monocyclic alicyclic hydrocarbon group having 3 to 12 ring atoms. Ar.sup.1 represents a group obtained by removing (q+1) hydrogen atoms on an aromatic ring from an arene formed by condensation of at least two benzene rings; R.sup.4 represents a monovalent organic group having 1 to 20 carbon atoms; q is an integer of 0 to 7; and R.sup.5 represents a halogen atom, a hydroxy group, a nitro group, or a monovalent organic group having 1 to 20 carbon atoms, or the like.

##STR00001##

A photoacid generator (PAG) anion, a photoresist composition, and a method are disclosed. The PAG anion includes a moiety, selected from an alkyl group, a monocyclic aromatic group, and a bicyclic aromatic group, that includes a carbon atom with a negative elementary charge. The PAG anion also includes an electron acceptor atom, selected from boron(III), aluminum(III), and phosphorus(V), which is covalently bonded to the carbon atom. The PAG anion also has at least one electron-withdrawing R group. The photoresist composition has a PAG that includes the PAG anion and a cation selected from triphenylsulfonium, diphenyliodonium, phenylthiolanium, and derivatives thereof. The method includes forming a layer of the photoresist composition over a material surface on a substrate, irradiating the layer to form a pattern of radiation-exposed regions, selectively removing portions of the irradiated layer to form exposed portions of the material surface, and etching or ion implanting the exposed portions.

A photoacid generator (PAG) anion, a photoresist composition, and a method are disclosed. The PAG anion includes a moiety, selected from an alkyl group, a monocyclic aromatic group, and a bicyclic aromatic group, that includes a carbon atom with a negative elementary charge. The PAG anion also includes an electron acceptor atom, selected from boron(III), aluminum(III), and phosphorus(V), which is covalently bonded to the carbon atom. The PAG anion also has at least one electron-withdrawing R group. The photoresist composition has a PAG that includes the PAG anion and a cation selected from triphenylsulfonium, diphenyliodonium, phenylthiolanium, and derivatives thereof. The method includes forming a layer of the photoresist composition over a material surface on a substrate, irradiating the layer to form a pattern of radiation-exposed regions, selectively removing portions of the irradiated layer to form exposed portions of the material surface, and etching or ion implanting the exposed portions.

A novel onium salt of formula (1) and a chemically amplified 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 has a high sensitivity and reduced acid diffusion and is improved in exposure latitude, MEF, and LWR. ##STR00001##

A novel onium salt of formula (1) and a chemically amplified 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 has a high sensitivity and reduced acid diffusion and is improved in exposure latitude, MEF, and LWR. ##STR00001##

A sulfonium salt represented by a following general formula (1),

##STR00001##

wherein in the general formula (1), each of R.sup.1 to R.sup.3 is independently an alkyl group, an aryl group, or a heteroaryl group;

at least one carbon-carbon single bond contained in the alkyl group is optionally substituted with a carbon-carbon double bond or a carbon-carbon triple bond;

at least one methylene group contained in the alkyl group is optionally substituted with at least one divalent heteroatom-containing group;

Ar.sup.1 is an arylene group;

at least one of R.sup.1, R.sup.2, R.sup.3 and Ar.sup.1 has at least one substituent (R);

at least two of R.sup.1 to R.sup.3, Ar.sup.1, and substituent (R) optionally form a ring;

A is a divalent group selected from a group consisting of —S—, —SO—, and —SO.sub.2—;

Ar.sup.1 is substituted with A at an ortho-position with respect to a sulfonio group (S.sup.+); and

X.sup.− is an anion.

A sulfonium salt represented by a following general formula (1),

##STR00001##

wherein in the general formula (1), each of R.sup.1 to R.sup.3 is independently an alkyl group, an aryl group, or a heteroaryl group;

at least one carbon-carbon single bond contained in the alkyl group is optionally substituted with a carbon-carbon double bond or a carbon-carbon triple bond;

at least one methylene group contained in the alkyl group is optionally substituted with at least one divalent heteroatom-containing group;

Ar.sup.1 is an arylene group;

at least one of R.sup.1, R.sup.2, R.sup.3 and Ar.sup.1 has at least one substituent (R);

at least two of R.sup.1 to R.sup.3, Ar.sup.1, and substituent (R) optionally form a ring;

A is a divalent group selected from a group consisting of —S—, —SO—, and —SO.sub.2—;

Ar.sup.1 is substituted with A at an ortho-position with respect to a sulfonio group (S.sup.+); and

X.sup.− is an anion.