Sulfonium salt, acid diffusion inhibitor, resist composition, and patterning process

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

• wherein R1, R2, and R3 each independently represent a fluorine atom, a hydroxy group, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, a carbamoyl group, an amide group, or a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 15 carbon atoms and optionally having a heteroatom, and a methylene group in the hydrocarbon group may be replaced with an ether bond (—O—) or a carbonyl group (—CO—);
• R1 and R2 may be bonded to each other to form a ring together with a benzene ring and a sulfur atom, R2 and R3 may be bonded to each other to form a ring together with a benzene ring and a sulfur atom, and when the ring is formed, R1 and R2, and R2 and R3 may combine to form a single bond, a divalent group, or a divalent atom;
• “r” represents an integer of 0 to 4, “p” represents an integer of 0 to 5, “q” represents an integer of 0 to 5, “x” represents an integer of 0 to 4, “y” represents an integer of 0 to 5, “z” represents an integer of 0 to 5, and “r”, “p”, “q”, “x”, “y”, and “z” satisfy x+y+z≥1, 4≥r+x≥0, 5≥p+y≥0, and 5≥q+z≥0;
• R1s may be the same or different from each other when r≥2, R2s may be the same or different from each other when p≥2, and R3s may be the same or different from each other when q≥2.