Electron molecule collisions for the science of plasma processing

Summary form only given, as follows. Plasma processing of materials has emerged as the enabling technology for many industrial applications ranging from the fabrication of microelectronic circuits to coatings for advanced combustion engines. There are also applications in waste treatment, chemical processing, and medicine. After impressive, mainly empirical successes, further developments now require more precise control and understanding of the mechanisms for selective deposition, etching, or reaction. The electron temperature of a non-equilibrium plasma can easily be 20,000 K while the gas temperature is less than 500 K. The reactivity of the plasma-excited gases is often enhanced by many orders of magnitude. Reliable collisional data for non-traditional gases such as BCl/sub 3/, (C/sub 2/H/sub 5/O)/sub 4/Si, SiF/sub 4/, and ((C/sub 2/H/sub 5/)/sub 2/N)/sub 4/Ti are critical to modeling and scaling industrial processes. Electron and ion collisions, especially those causing dissociation of the initial gases, and reactions of the resulting radicals with gases and at surfaces are crucial. Extant collisional data and methods are reviewed in the context of emerging technological requirements. Examples are presented for i) 'crossed-beam' and 'swarm' studies of electron-molecule collisions, ii) Fourier Transform Mass Spectroscopy probes of dissociative ionization, attachment, and charge-transfer collisions, and iii) Surface Desorption Spectroscopy examinations of surface reactions.