A chemical mechanical planarization solution is useful for removing tantalum barrier materials. The solution includes by weight percent 0 to 25 oxidizer, 0 to 15 inhibitor for a nonferrous metal and 0 to 20 complexing agent for the nonferrous metal, 0.01 to 12 tantalum removal agent selected from the group consisting of formamidine, formamidine salts, formamidine derivatives, guanidine derivatives, guanidine salts and mixtures thereof, 0 to 5 abrasive, 0 to 15 total particles selected from the group consisting of polymeric particles and polymer-coated coated particles and balance water. The solution has a tantalum nitride to TEOS selectivity of at least 3 to 1 as measured with a microporous polyurethane polishing pad pressure measure normal to a wafer less than 20.7 kPa.