Novel Sulfonium Salt, Resist Composition, And Patterning Process

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

• wherein “p” represents an integer of 1 to 3;
• R11 represents a hydrocarbyl group having 1 to 20 carbon atoms and optionally having a heteroatom;
• two of the three substituents bonded to the sulfonium cation are optionally bonded each other to form a ring together with the sulfur atom to which the two substituents are bonded;
• Rf represents a fluorine atom, a fluorine-atom-containing alkyl group, a fluorine-atom-containing alkoxy group, or a fluorine-atom-containing sulfide group, each group having 1 to 6 carbon atoms;
• “q” represents an integer of 1 to 4, and when q≥2, Rf may be same as or different from each other;
• RALU represents an acid-labile group formed together with the adjacent oxygen atom;
• “r” represents an integer of 1 to 4;
• R12 represents a hydrocarbyl group having 1 to 20 carbon atoms and optionally having a heteroatom;
• “s” represents an integer of 0 to 4;
• “t” represents an integer of 0 to 2;
• q+r+s≤5 when t=0, q+r+s≤7 when t=1, and q+r+s≤9 when t=2;
• Rf and —O—RALU are bonded to adjacent carbon atoms;
• and X− represents a non-nucleophilic counterion having no polymerizable group.