In-situ measurements of etch rates in an electron-beam produced plasma reactor

Summary form only given, as follows. NRL´s ´Large Area Plasma Processing System´ is based on plasma production using high energy electron beams, with the goal of modifying the surface properties of materials. LAPPS produces plasmas with characteristics ideal for dry processing of materials: high-density plasmas with low internal fields and low electron temperature. To investigate LAPPS´s capability to etch simple materials such as silicon, an in situ interferometer was implemented on a system with a moderately sized, pulsed plasma sheet. Etch rates were determined as a function of gas composition, plasma conditions and RF-induced stage bias voltage. Gas compositions consisted of various mixtures of halogenated gases with background gases such as oxygen and argon. Plasma conditions investigated included varying external magnetic field strength, total gas pressure and duty cycle. Typical measured etch rates were 100-500 nm/min. Results from SEM measurements of process anisotropy and area uniformity will also be presented.