Patent ID: 7790618

Claim:
An aqueous solution useful for selective barrier removal in the presence of a low-k dielectric comprising by weight percent 0 to 25 oxidizer; 0.00002 to 5 multi-component surfactant, the multi-component surfactant consisting of a hydrophobic tail, a nonionic hydrophilic portion and an anionic hydrophilic portion, the anionic hydrophilic portion consists of carboxylic acid, sulfonic acid, sulfuric acid and salts thereof or mixtures thereof, the hydrophobic tail having 6 to 30 carbon atoms and the nonionic hydrophilic portion being a straight chain of polyethylene oxide having 20 to 200 carbon atoms; 0.1 to 10 weight percent barrier removal agent selected from at least one of formamidine, formamidine salts, formamidine derivatives, guanidine, guanidine derivatives, guanidine salts and a mixture thereof; 0 to 15 inhibitor for a nonferrous metal; 0 to 50 abrasive; 0 to 20 complexing agent for a nonferrous metal; and water; and the aqueous solution having a TaN/CDO removal rate selectivity of at least 2 to 1 as measured with a microporous polyurethane polishing pad pressure measured normal to a wafer of less than 13.8 kPa.