An onium salt having the following formula (1) is provided. In formula (1), one of R.sup.13 and R.sup.14 is a group having a partial structure of the following formula (1a). Q.sup.1 to Q.sup.3 are each independently a hydrogen atom, a fluorine atom, or a C.sub.1-C.sub.6 fluorinated saturated hydrocarbyl group, provided that, when both of Q.sup.1 and Q.sup.2 are a hydrogen atom, Q.sup.3 is a fluorine atom or a C.sub.1-C.sub.6 fluorinated saturated hydrocarbyl group, and the total number of fluorine atoms in Q.sup.1 to Q.sup.3 is 2 or more.

##STR00001##

A radiation-sensitive composition contains a polymer having a partial structure represented by formula (1), and a radiation-sensitive acid generating substance. The radiation-sensitive composition satisfies one or more of requirement 1, requirement 2, and requirement 3. requirement 1: the partial structure represented by the formula (1) has two or more iodine atoms. requirement 2: the radiation-sensitive acid generating substance contains an onium salt having two or more iodine atoms. requirement 3: the partial structure represented by the formula (1) has an iodine atom, and the radiation-sensitive acid generating substance contains an onium salt having an iodine atom. In the formula (1), Y.sup.1 represents a divalent group represented by formula (2-1) or formula (2-2).

##STR00001##

The present invention provides an actinic ray-sensitive or radiation-sensitive resin composition with which a pattern having excellent LWR performance can be obtained, a resist film, a pattern forming method, a method for manufacturing an electronic device, a compound, and a method for producing the compound. The actinic ray-sensitive or radiation-sensitive resin composition of an embodiment of the present invention is an actinic ray-sensitive or radiation-sensitive resin composition including a resin having a repeating unit having a group having a polarity that increases through decomposition by the action of an acid, in which the actinic ray-sensitive or radiation-sensitive resin composition further includes, in addition to the resin, a compound having at least one cation represented by General Formula (1), or the resin further has, in addition to the repeating unit, a repeating unit having the cation represented by General Formula (1).
(R.sup.d1).sub.m[X.sup.d1].sup.+-(L.sup.d1-Ar.sup.d1(SX.sup.d2).sub.p).sub.n (1)