Non-collisional heating in inductively coupled plasma sources

Abstract

Summary form only given. In inductively coupled plasma (ICP) reactors for microelectronics fabrication, the plasma is sustained by an electromagnetic (EM) wave generated by an external antenna. In models of radio frequency (rf) ICP reactors, the charged particle transport is addressed using a variety of methods including fluid, kinetic or Monte Carlo (MC) techniques. The plasma dynamics are usually coupled back to the EM wave through Ohm's law, which relates the electric field to the plasma current. Ohm's law, which only considers collisional heating, is strictly accurate only when the electron collision frequency is commensurate or greater than the rf frequency. Previous studies have suggested that additional heating mechanisms are present at lower gas pressures (<10-20 mTorr) in the reactors of interest. In this paper, we report on a new algorithm whose intent is to a provide more accurate description of non-collisional plasma-EM wave coupling at low pressures in ICP reactors where ohmic heating may not be strictly applicable. The algorithm is implemented in a 2-dimensional model for an ICP plasma etching reactor.