The Impact of Wafer Topography Issues on The Next Generation Process

摘要

In the Shallow Trench Isolation (STI) process,a newly-emerged wafer topography,nanotopography,has been emphasized to result in the thickness variations of oxide films remaining after CMP.In the typical polishing,the films on raised areas of nanotopography features can be removed faster than those on lower areas.This results in the oxide films remaining in lower areas because polishing must be stop almost as soon as the oxide in raised areas is completely polished away.