Time-Modulated Electron Cyclotron Resonance Plasma Discharge for Controlling the Polymerization in SiO2 Etching

Abstract

This study examines 10-100 µs modulated electron cyclotron resonance (ECR) plasma discharge for controlling the generation of reactive species in plasmas. The electron temperature, density and reactive species are measured by means of a Langmuir probe and an actinometric optical emission spectroscopy in the pulsed plasma. Good correlation is found between the density ratio of CF2 radicals and F atoms in the CHF3 plasma, and the combination of the pulse duration and intervals. These characteristics are explained in terms of the dependence of the generation of reactive species in the ECR plasma on time (10-100 µs). This method provides for control of the polymerization and achievement of highly selective etching to Si during SiO2 etching.