Negative resist composition and patterning process using same

A negative resist composition, comprising an organic solvent and. as a base resin thereof, a novolak resin which contains repeating unit “a” shown by the following general formula (1) and repeating unit “b1” shown by the following formula (2),

• wherein R1 represents a hydrogen atom, a hydroxy group, or any of a linear, a branched, or a cyclic alkyl group, alkoxy group, acyl group, acyloxy group, and alkoxy carbonyl group, these groups having 1 to 6 carbon atoms;
• and R2 represents a hydrogen atom, or any of a linear, a branched, or a cyclic alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms, wherein these groups may optionally contain a hydroxy group, an alkoxy group. an ether group, a thioether group, a carboxyl group, an alkoxy carbonyl group, and an acyloxy group;
• wherein, “a” is within the range of 0<a<1;
• wherein R2 represents the same meaning as before;
• R3 and R4 represent a hydrogen atom, or any of a linear, a branched, or a cyclic alkyl group or acyl group having 1 to 6 carbon atoms;
• and R5 and R6 represent a hydrogen atom, or any of a linear, a branched, or a cyclic alkyl group having 1 to 6 carbon atoms, wherein these groups may be optionally substituted by a halogen atom partially or all of them;
• R7 represents a single bond, or any of a linear, a branched, or a cyclic alkylene group having 1 to 20 carbon atoms, or a linear, a branched, or a cyclic alkenylene group having 2 to 20 carbon atoms, or an arylene group having 6 to 20 carbon atoms, wherein these groups may optionally contain a nitrogen atom, a hydroxy group, a carboxyl group, an alkoxy carbonyl group, an acyloxy group, an ether group, an ester group, a thioether group, or a lactone ring;
• R5 and R6 may be optionally bonded to form an ether ring;
• wherein, “m” and “n” each represents 0 or 1;
• and “b1” is within the range of 0<b1<1.