A new kind of chelating agent with low pH value applied in the TSV CMP slurry*Project supported by the Major National Science and Technology Special Projects (No. 2009ZX02308), the Fund Project of Hebei Provincial Department of Education, China (No. QN2014208), the Natural Science Foundation of Hebei Province, China (No. E2013202247), and the Colleges and Universities Scientific Research Project of Hebei Province, China (No. Z2014088). (December 2015)