구리막 화학기계적 연마 공정에서 평탄도와 디싱을 개선하기 위한 콜로이달 실리카 입자 표면 제어

Abstract

Control of colloidal silica surface for improving surface roughness and dishing in copper chemical mechanical planarization was investigated. We employed two methods that the surface property of colloidal silica changes. The one was synthesis of modified silica which had functional groups like brush on surface and the other was adsorption of polymer which was coiled by transforming the conformation on silica surface. Modified silica which had functional groups was confirmed by results of electrokinetic sonic amplitude (ESA) and COF values which indicated surface charge and hardness were changed. The adsorption of Polyethyleneimine (PEI) on colloidal silica and the changed surface character that adsorbed amount and conformation of polymer were changed were measured using total organic carbon (TOC) and atomic force microscopy (AFM). After Cu CMP was performed, the improvement of surface roughness and dishing was evaluated by AFM.