Polyorganosiloxane, resin composition, and patterning process

A polyorganosiloxane compound having the average compositional formula (1) which is modified such that some hydrogen atoms of silicon-bonded hydroxyl groups are substituted by acid labile groups of the general formula (2) and/or are crosslinked within the molecule or between molecules with a crosslinking group having a C—O—C linkage represented by the general formula (3), said polyorganosiloxane compound having a weight average molecular weight of 300 to 200,000 as measured by GPC versus polystyrene standards,

• R1aSi(OR2)b(OH)cO(4−a−b−c)/2 (1)
• wherein R1 is one or more groups selected from hydrogen and C1-C18 organic groups, R2 is one or more groups selected from straight or branched C1-C6 alkyl groups, a, b and c are numbers in the range:
• 0.3≦a≦1.6, 0≦b≦0.3, and 0.001≦c≦2,
• wherein R3 and R4 are each independently hydrogen or a straight, branched or cyclic C1-C6 alkyl group, R5 is a straight, branched or cyclic C1-C30 alkyl group, C6-C20 aryl group or C7-C20 aralkyl group, or R3 and R4, R3 and R5, or R4 and R5 may bond together to form a ring with the carbon atom or carbon and oxygen atoms to which they are attached, wherein ring-forming R3, R4 or R5 is a straight or branched C1-C18 alkylene group,
• wherein R6, R7, R9 and R10 are each independently hydrogen or a straight, branched or cyclic C1-C6 alkyl group, or R6 and R7, or R9 and R10 may bond together to form a ring with the carbon atom to which they are attached, wherein ring-forming R6, R7, R9 or R10 is a straight or branched C1-C17 alkylene group, and R8 is a divalent C1-C6 hydrocarbon group which may contain an oxygen atom.