The Shallow Trench Isolation (STI) Chemical Mechanical Planarization (CMP) step is a critical planarization process situated immediately after the Pre-CMP Oxide Deposition and prior to the STI CMP Post Cleaning module P4.The primary objective of this step is to completely remove the overburden silicon dioxide while utilizing the underlying silicon nitride (Si3N4) film as a rigid polish stop layer P4.This process physically defines the active transistor boundaries by isolating them with dielectri