Negative resist composition and resist pattern forming process

A negative resist composition comprising

• (A) a sulfonium compound having the formula (A):
• wherein R1, R2 and R3 are each independently a C1-C20 straight, branched or cyclic monovalent hydrocarbon group which may contain a heteroatom, p and q are each independently an integer of 0 to 5, r is an integer of 0 to 4, in case of p=2 to 5, two adjoining groups R1 may bond together to form a ring with the carbon atoms to which they are attached, in case of q=2 to 5, two adjoining groups R2 may bond together to form a ring with the carbon atoms to which they are attached, and in case of r=2 to 4, two adjoining groups R3 may bond together to form a ring with the carbon atoms to which they are attached, and
• (B) a base polymer containing a polymer comprising recurring units having the formula (B1):
• wherein RA is hydrogen, fluorine, methyl or trifluoromethyl, R11 is each independently halogen, an optionally halogenated C2-C8 straight, branched or cyclic acyloxy group, optionally halogenated C1-C6 straight, branched or cyclic alkyl group, or optionally halogenated C1-C6 straight, branched or cyclic alkoxy group, A1 is a single bond or a C1-C10 straight, branched or cyclic alkylene group in which an ether bond may intervene in a carbon-carbon bond, s is 0 or 1, w is an integer of 0 to 2, a is an integer in the range:
• 0≤a≤5+2w−b, and b is an integer of 1 to 3.