Following the "STI Fill Conformal CVD Oxide" step, the deposited dielectric film is typically porous and possesses suboptimal structural integrity P2.To adequately prepare for the subsequent "Pre-CMP Oxide Deposition" and "STI CMP" steps, the filled oxide must undergo a high-temperature thermal anneal T1.This anneal drives out trapped impurities, densifies the conformal CVD film, and prevents CMP slurry or subsequent wet etchants from excessively attacking the isolation oxide P2.Without this den