Patent ID: 8062395
Filing Date: 2011-11-22
Classification: C09G,C09K,H01L

Abstract:
1. An adjuvant for protecting silicon nitride layer in use for a process of polishing a cationically charged material and an anionically charged material at the same time with abrasive particles, wherein the adjuvant is absorbed onto the cationically charged material thereby to restrain the cationically charged material from being polished, resulting in raising a polishing selectivity of the anionically charged material, wherein the adjuvant comprises polymer particles having a core-shell structure with a nano-scale particle size smaller than that of the abrasive particles, surfaces of which are anionically charged, wherein the adjuvant has a pH ranging from 4.5 to 8.8, and wherein the polymer particles have a surface potential ranging up to −25 mV.