Composition for metal plating comprising suppressing agent for void free submicron feature filling

A composition comprising:

• a copper ion source and
• at least one suppressing agent produced by a process comprising reacting:
• a) a polyhydric alcohol condensate starter, which is a condensation derivative of the formula
• X(OH)m
• with
• b) an alkylene oxide,
• to produce a polyhydric alcohol condensate comprising polyoxyalkylene side chains,
• wherein
• m is an integer from 3 to 6, and
• X is a m-valent, linear or branched, aliphatic or cycloaliphatic radical having from 3 to 10 carbon atoms, wherein the radical is unsubstituted or substituted with one or more substituent groups selected from the group consisting of a cyano, hydroxyl, halo, (C1-C6) alkoxy, (C1-C6) alkylthio, thiol and nitro group;
• and
• an accelerating agent.