2D SIMULATION OF PARTICLE FORMATION, GROWTH, AND DEPOSITION IN LOW-PRESSURE CVDS - APPLICATION OF CONTAMINATE VERSION 2.0

As part of Hitachi's development of clean semiconductor processing equipment, the Fluids Modeling Group of the Mechanical Engineering Research Laboratory is developing a computer model, CONTAMINATE, for simulating contamination of wafers in chemical vapor deposition (CVD) systems. CONTAMINATE is based on a 2D implementation of the SIMPLER algorithm for simulating convection/diffusion transport processes(1). The new model includes modules for simulating fluid flow, heat transfer, chemical reactions, and gas-phase formation and deposition of clusters and particles. CONTAMINATE outputs property fields and estimates of various film quality indices. Using CONTAMINATE we simulated a SiH4: O2: N2 gas mixture at 300 K flowing over a wafer heated to 700 K. System pressures were varied from 1-100 torr and SiH4 pressures from 0.1 to 10 torr. Deposition characteristics are in qualitative agreement with actual systems and are summarized as follows: No particles larger than 0.1-mu-m deposited for any of the conditions tested. Film damage occurred above 10 torr, but no damage occurred below 10 torr. Increasing SiH4 pressure at constant system pressure eliminated particle deposition because particles grew large enought that thermophoresis blocked particle diffusion. Conformal deposition on featured surfaces was achieved only at 1 torr. Film thickness variation over the diameter of the wafer was 15% at 100 torr, 3% at 10 torr, and 1% at 1 torr.