Chemical Reaction Mechanisms for Modeling the Fluorocarbon Plasma Etch of SiliconOxide and Related Materials

摘要

As part of a project with SEMATECH, detailed chemical reaction mechanisms havebeen developed that describe the gas-phase and surface chemistry occurring during the fluorocarbon plasma etching of silicon dioxide and related materials. The fluorocarbons examined are C(sub 2)F(sub 6), CHF(sub 3) and C(sub 4)F(sub 8), while the materials studied are silicon dioxide, silicon, photoresist, and silica-based low-k dielectrics. These systems were examined at different levels, ranging from in-depth treatment of C(sub 2)F(sub 6) plasma etch of oxide, to a fairly cursory examination of C(sub 4)F(sub 8) etch of the low-k dielectric. Simulations using these reaction mechanisms and AURORA, a zero-dimensional model, compare favorably with etch rates measured in three different experimental reactors, plus extensive diagnostic absolute density measurements of electron and negative ions, relative density measurements of CF, CF(sub 2), SiF and SiF(sub 2) radicals, ion current densities, and mass spectrometric measurements of relative ion densities.