Positive resist composition and patterning process

A positive resist composition comprising a compound having a nitrobenzyl ester group bonded to an iodized aromatic ring, wherein the compound having a nitrobenzyl ester group bonded to an iodized aromatic ring has the formula (1):

• wherein m is an integer of 1 to 3, n is an integer of 0 to 4, p is an integer of 0 to 4, or an integer of 1 to 4 when m is 2 or 3, q is 1 or 2, r is an integer of 0 to 3, meeting 1≤p+q+r≤5,
• in case of m=1, R0 is hydrogen, iodine, or a C20-C40 hydrocarbyl group having a steroid skeleton and optionally containing a heteroatom, in case of m=2, R0 is an ether bond, thioether bond, ester bond, thioester bond, amide bond, urethane bond, urea bond, carbonate bond, or a C1-C40 hydrocarbylene group which may contain a heteroatom, and in case of m=3, R0 is a C1-C40 trivalent hydrocarbon group which may contain a heteroatom;
• the hydrocarbyl, hydrocarbylene or trivalent hydrocarbon group may bond to the benzene ring in the formula via an ether bond, thioether bond, ester bond, thioester bond, amide bond, urethane bond, urea bond or carbonate bond, with the proviso that R0 is iodine in case of m=1 and p=0,
• R1 is each independently hydroxy, C1-C6 saturated hydrocarbyl group, C1-C6 saturated hydrocarbyloxy group, C2-C6 saturated hydrocarbylcarbonyloxy group, C1-C4 saturated hydrocarbylsulfonyloxy group, fluorine, chlorine, bromine, amino, nitro, cyano, —N(R1A)(R1B), —N(R1C)—C(═O)—R1D, —N(R1C)—C(═O)—O—R1D, or —N(R1C)—S(═O)2—R1D, wherein R1A is a C1-C6 saturated hydrocarbyl group, R1B is hydrogen or a C1-C6 saturated hydrocarbyl group, R1C is hydrogen or a C1-C6 saturated hydrocarbyl group, R1D is a C1-C8 aliphatic hydrocarbyl group or C6-C10 aryl group, the saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, saturated hydrocarbylsulfonyloxy group, and aliphatic hydrocarbyl group may have some or all of the hydrogen atoms substituted by halogen and may have an ether bond or ester bond intervening in a carbon-carbon bond, and the aryl group may have some or all of the hydrogen atoms substituted by halogen or hydroxy,
• R2 is a single bond or C1-C6 saturated hydrocarbylene group,
• R3 is nitro, halogen, a C1-C10 aliphatic hydrocarbyl group, or C1-C10 aliphatic hydrocarbyloxy group, in case of n=2, 3 or 4, two R3 may bond together to form a ring with the carbon atoms to which they are attached, and
• R4 is hydrogen or a C1-C4 alkyl group.