A resist composition including a resin component having a structural unit derived form a compound represented by formula (a0-1) (in the formula, W represents a polymerizable group-containing group; Ra.sup.01 is a group which is bonded to Ra.sup.03 to form an aliphatic cyclic group, or bonded to Ra.sup.04 to form an aliphatic cyclic group;

Ra.sup.02 represents a hydrocarbon group which may have a substituent; Ra.sup.03 is a hydrogen atom or a monovalent organic group in the case where Ra.sup.01 is not bonded thereto; Ra.sup.04 is a hydrogen atom or a monovalent organic group in the case where Ra.sup.01 is not bonded thereto; and Ra.sup.05 to Ra.sup.07 each independently represents a hydrogen atom or a monovalent organic group).

##STR00001##

Low refractive index and high dispersion material which can produce a bonded-multilayer DOE having an excellent optical performance is obtained, and the optical member using this is obtained. The resin precursor for optical materials obtained through the addition reaction of the composite containing a di (meth) acrylate shown in the following Chemical Expression 1.

##STR00001## where, RH or CH.sub.3, and m+n=1 to 10.

Low refractive index and high dispersion material which can produce a bonded-multilayer DOE having an excellent optical performance is obtained, and the optical member using this is obtained. The resin precursor for optical materials obtained through the addition reaction of the composite containing a di (meth) acrylate shown in the following Chemical Expression 1.

##STR00001## where, RH or CH.sub.3, and m+n=1 to 10.

A resist composition which generates acid upon exposure and exhibits changed solubility in a developing solution under action of acid, the resist composition including: a base component which exhibits changed solubility in a developing solution under action of acid and a fluorine additive component which exhibits decomposability to an alkali developing solution, the fluorine additive component including a fluorine resist component having a structural unit derived from a compound represented by general formula (f1-1) in which W represents a polymerizable group-containing group; Rf.sup.1 and Rf.sup.2 each independently represents a hydrogen atom or an electron-withdrawing group; and Rf.sup.3 represents a hydrocarbon group

##STR00001##

To provide a curable composition whereby it is possible to obtain a cured product having a high Abbe number and being excellent in transparency, crack resistance and releasability; and such a cured product. A curable composition comprises, in specific ratios, surface-modified metal oxide particles (A) having (meth)acryloyl-group-containing surface-modifying groups on the surface of the metal oxide particles, a compound (B) having a fluorine atom and at least one (meth)acryloyl group, a compound (C) having a urethane bond or OCH.sub.2CH(OH)CH.sub.2, having at least two (meth)acryloyl groups and having a mass-average molecular weight of at least 1,000, a compound (D) having no unsaturated bond-containing ring structure and having at least one (meth)acryloyl group, and a polymerization initiator (E).

To provide a curable composition whereby it is possible to obtain a cured product having a high Abbe number and being excellent in transparency, crack resistance and releasability; and such a cured product. A curable composition comprises, in specific ratios, surface-modified metal oxide particles (A) having (meth)acryloyl-group-containing surface-modifying groups on the surface of the metal oxide particles, a compound (B) having a fluorine atom and at least one (meth)acryloyl group, a compound (C) having a urethane bond or OCH.sub.2CH(OH)CH.sub.2, having at least two (meth)acryloyl groups and having a mass-average molecular weight of at least 1,000, a compound (D) having no unsaturated bond-containing ring structure and having at least one (meth)acryloyl group, and a polymerization initiator (E).

The present invention relates to a photocurable resin composition usable in a nanoimprint process which is capable of overcoming low productivity of conventional semiconductor processes for optical devices and electronic devices, and a method of forming patterns using the same. Specifically, the present invention relates to a photocurable resin composition including a specific perfluorinated acrylic compound for improving release property between a nanoimprint mold and the photocurable resin composition, and a method of forming patterns using the same.

A resist composition includes (A1) a resin which includes a structural unit represented by formula (a4), a structural unit having a cyclic carbonate and a structural unit represented by formula (I), the resin has no acid-labile group; (A2) a resin which has an acid-labile group; and an acid generator: ##STR00001##
wherein R.sup.3 represents a hydrogen atom or a methyl group, R.sup.4 represents a C.sub.1 to C.sub.24 saturated hydrocarbon group having a fluorine atom, and a methylene group contained in the saturated hydrocarbon group may be replaced by an oxygen atom or a carbonyl group, R.sup.1 represents a hydrogen atom or a methyl group, and L.sup.1 represents a single bond or a C.sub.1 to C.sub.18 divalent saturated hydrocarbon group where a methylene group may be replaced by an oxygen atom or a carbonyl group, and R.sup.2 represents a C.sub.3 to C.sub.18 alicyclic hydrocarbon group where a hydrogen atom may be replaced by a C.sub.1 to C.sub.8 aliphatic hydrocarbon group or a hydroxy group, provided that the carbon atom directly bonded to L.sup.1 has no aliphatic hydrocarbon group by which a hydrogen atom has been replaced.

A resist composition includes (A1) a resin which includes a structural unit represented by formula (a4), and a structural unit having an adamantane lactone group, and the resin has no acid-labile group, (A2) a resin having an acid-labile group, and an acid generator. ##STR00001##
In the formula (a4), R.sup.3 represents a hydrogen atom or a methyl group, and R.sup.4 represents a C.sub.1 to C.sub.24 saturated hydrocarbon group having a fluorine atom, and a methylene group of the saturated hydrocarbon group may be replaced by an oxygen atom or a carbonyl group.

Radiopaque polymer compositions and methods for making the compositions are provided. These radiopaque polymer compositions include polymer compositions comprising a crosslinked polymer network, the network comprising a first repeating unit derived from a monofunctional monomer and a second repeating unit derived from a multifunctional non-iodinated monomer wherein neither of the two monomers is fluorinated. Devices formed from radiopaque polymer compositions are also provided.