Simulation-Driven Optimization of STI Etching: A Systematic Approach to Defect Reduction

The shallow trench isolation (STI) etching process frequently faces defects like etch stop and pitting, resulting from complex interactions across multiple steps. In this study, calibrated simulations were pivotal in systematically analyzing these defects. The simulations allowed us to predict how variations in process parameters, particularly oxygen concentration, contributed to the etch stop, enabling us to optimize the gas ratio and achieve uniform etching rapidly. Additionally, simulations guided the introduction of a breakthrough step and the adjustment of the stripe process sequence, leading to significant reductions in pitting. This simulation-driven approach, validated by experimental results, proved highly efficient in identifying the root causes of these defects and determining the optimal process recipe for STI etching.