Large area plasma processing system based on electron beam ionization

Abstract

Summary form only given. Electron beam ionization is both efficient at producing plasma and scalable to large area (square meters) with beam energy and density. A 'Large Area Plasma Processing System' has been developed based on the beam ionization process, with the goal of modifying the surface properties of materials over large areas. The system consists of a planar plasma distribution generated by a magnetically collimated sheet of 2-5 kV, /spl sim/10 mA/cm/sup 2/ electrons injected into a neutral gas background (oxygen, nitrogen, argon, neon). Beam ionization largely decouples plasma production from the reactor chamber, and ion densities of up to 5/spl times/10/sup 12/ cm/sup -3/ in large volumes (2 cm/spl times/60 cm/spl times/60 cm) have been produced in dielectric as well as conducting chambers. Typical operating pressures range from 20-200 mtorr with beam-collimating magnetic fields strengths of 10-300 Gauss. Thus far, electron beams have been produced using pulsed (10-4000 /spl mu/s pulse length, >50% duty cycle) and DC hollow cathode discharges. Temporally resolved plasma characteristics deduced from Langmuir probes, optical emission spectroscopy and microwave interferometry will be presented for noble and molecular gases. Similarly, temporally resolved plasma-to-surface fluxes (via mass spectrometry) and their energy distributions will be presented to give further insight into LAPPS for material processing applications.