Model etch profiles for argon and chlorine ion energy distribution functions in inductively coupled discharge plasmas

Abstract

Summary form only given. Measured argon and chlorine ion energy and angular distribution functions are fitted to drifted Maxwellian distribution functions by a simulated annealing procedure. The ion energy and angular distribution functions have been measured in inductively coupled radio frequency discharges in argon and chlorine plasmas in a modified GBE reference cell. The ion energy distribution function data for several gas pressures and RF powers are a good fit to one drifted Maxwellian and an excellent fit to two drifted Maxwellians in most cases. Etch rates for trenches are calculated for the fitted ion energy distribution functions from approximate analytical expressions found previously for drifted Maxwellians. The etch rate expressions are valid in the ion flux-limited regime where the etch rate is proportional to the ion energy flux for long rectangular trenches. Trench etch profiles on semiconductor wafers are calculated numerically from the trajectory equations of the etch profile equation with the computer program MatLab.