A resist composition including a compound represented by formula (b1) in which R.sup.b1 represents an aryl group which may have a substituent; R.sup.b2 and R.sup.b3 each independently represents an aryl group which may have a substituent or an alkyl group which may have a substituent; provided that at least one of the aryl group represented by R.sup.b1 and the aryl group or the alkyl group represented by R.sup.b2 or R.sup.b3 has a substituent containing a halogen atom, and at least one of the aryl group represented by R.sup.b1 and the aryl group or the alkyl group represented by R.sup.b2 or R.sup.b3 has a substituent containing a sulfonyl group; and X.sup.− represents a counteranion ##STR00001##

A monomer has the structure

##STR00001##

wherein R is an organic group comprising a polymerizable carbon-carbon double bond or carbon-carbon triple bond; X and Y are independently at each occurrence hydrogen or a non-hydrogen substituent; EWG1 and EWG2 are independently at each occurrence an electron-withdrawing group; p is 0, 1, 2, 3, or 4; n is 1, 2, 3, or 4; and M.sup.+ is an organic cation. A polymer prepared from monomer is useful as a component of a photoresist composition.

Disclosed herein is a lipid having a net charge at physiological pH, and being covalently attached to a lipid moiety. The lipid moiety comprises a hydrocarbon structure having two or more linked hydrocarbon chains, optionally having cis or trans C═C, at least one of said chains being covalently attached to the head group optionally via the linker region. The hydrocarbon chains are bonded to one another at a branch point at an internal carbon of the chain attached to the linker region, which branch point comprises a functional group having an electronegative atom. The hydrocarbon chains each have between 1 and 40 carbon atoms, wherein the hydrocarbon structure in total comprises between 10 and 150 carbon atoms. Advantageously, the hydrocarbon structure may assume a generally flared shape for enhanced delivery of cargo molecules. Further provided are delivery vehicles comprising the lipids.

A salt represented by formula (I): ##STR00001##
wherein R.sup.1 and R.sup.2 independently represent a hydrogen atom, a hydroxy group or a C.sub.1 to C.sub.12 hydrocarbon group in which a methylene group may be replaced by a —O— or —CO—; m and n independently represent 1 or 2; Ar represents an optionally substituted phenyl group; Q.sup.1 and Q.sup.2 independently represent a fluorine atom or a C.sub.1 to C.sub.6 perfluoroalkyl group, A.sup.1 represents a single bond, a C.sub.1 to C.sub.24 alkanediyl group or the like, and Y represents an optionally substituted C.sub.1 to C.sub.18 alkyl group or monovalent C.sub.3 to C.sub.18 alicyclic hydrocarbon group, and a methylene group therein may be replaced by a —O—, O— or —SO.sub.2—, provided that the alkyl group or the alicyclic hydrocarbon group has at least one substituent, or at least one methylene group contained therein is replaced by a —O—, —CO— or —SO.sub.2—.

A salt represented by formula (I): ##STR00001##
wherein R.sup.1 and R.sup.2 independently represent a hydrogen atom, a hydroxy group or a C.sub.1 to C.sub.12 hydrocarbon group in which a methylene group may be replaced by a —O— or —CO—; m and n independently represent 1 or 2; Ar represents an optionally substituted phenyl group; Q.sup.1 and Q.sup.2 independently represent a fluorine atom or a C.sub.1 to C.sub.6 perfluoroalkyl group, A.sup.1 represents a single bond, a C.sub.1 to C.sub.24 alkanediyl group or the like, and Y represents an optionally substituted C.sub.1 to C.sub.18 alkyl group or monovalent C.sub.3 to C.sub.18 alicyclic hydrocarbon group, and a methylene group therein may be replaced by a —O—, O— or —SO.sub.2—, provided that the alkyl group or the alicyclic hydrocarbon group has at least one substituent, or at least one methylene group contained therein is replaced by a —O—, —CO— or —SO.sub.2—.

A positive-type resist composition which generates an acid upon exposure and whose solubility in an alkali developing solution increases under the action of an acid, the composition including a base material component whose solubility in an alkali developing solution increases under the action of an acid; and a compound represented by the following general formula (m0): ##STR00001## Z.sup.01 to Z.sup.04 each independently represent a substituent having electron withdrawing properties, Rb.sup.21 and Rb.sup.22 each independently represent an alkyl group, an alicyclic hydrocarbon group which may have a substituent, or a hydroxyl group, Rb.sup.1 represents an aryl group which may have a substituent, an alkyl group, or an alkenyl group, n1 and n2 represent an integer of 0 to 3, and X0.sup.− represents an organic anion.

A positive-type resist composition which generates an acid upon exposure and whose solubility in an alkali developing solution increases under the action of an acid, the composition including a base material component whose solubility in an alkali developing solution increases under the action of an acid; and a compound represented by the following general formula (m0): ##STR00001## Z.sup.01 to Z.sup.04 each independently represent a substituent having electron withdrawing properties, Rb.sup.21 and Rb.sup.22 each independently represent an alkyl group, an alicyclic hydrocarbon group which may have a substituent, or a hydroxyl group, Rb.sup.1 represents an aryl group which may have a substituent, an alkyl group, or an alkenyl group, n1 and n2 represent an integer of 0 to 3, and X0.sup.− represents an organic anion.

A salt having a group represented by formula (a): ##STR00001## wherein X.sup.a and X.sup.b each independently represent an oxygen atom or a sulfur atom, X.sup.1 represents a divalent group having an alicyclic hydrocarbon group where a methylene group may be replaced by an oxygen atom or a carbonyl group, and where a hydrogen atom may be replaced by a hydroxy group or a fluorine atom, and * represents a binding site.

A salt having a group represented by formula (a): ##STR00001## wherein X.sup.a and X.sup.b each independently represent an oxygen atom or a sulfur atom, X.sup.1 represents a divalent group having an alicyclic hydrocarbon group where a methylene group may be replaced by an oxygen atom or a carbonyl group, and where a hydrogen atom may be replaced by a hydroxy group or a fluorine atom, and * represents a binding site.

An onium salt having a partial structure of formula (A) is provided wherein R.sup.a1 and R.sup.a2 are hydrogen or a C.sub.1-C.sub.10 hydrocarbyl group in which hydrogen may be substituted by halogen and —CH.sub.2— may be replaced by —O— or —C(═O)—, both R.sup.a1 and R.sup.a2 are not hydrogen at the same time, R.sup.a1 and R.sup.a2 may bond together to form an aliphatic ring. A chemically amplified negative resist composition comprising the onium salt as acid generator forms a pattern of good profile having a high sensitivity, improved dissolution contrast, reduced LWR and improved CDU.

##STR00001##