Characterization of defects produced in TEOS thin films due to chemical-mechanical polishing (CMP)

Abstract

Time zero breakdown electrical measurements, SIMS, Bias Temperature Stress (BTS), and Triangular Voltage Sweep (TVS) techniques performed on MOS capacitors have been used to characterize two types of defects produced in TEOS thin films subjected to CMP process planarization. Microcracking of the insulator, resulting in degradation in breakdown characteristics, and uptake of K+ ions (from the polishing slurry) are found to occur. These defects are thought to be caused by the chemical and mechanical stress to which the oxide surface is subjected during the CMP process. The effects of polish pad type, non K+ ion containing slurry and post-CMP wet etch steps were all found to influence the extent of damage observed in polished films.