The etching of silicon compounds by electron beams releases a plasma cloud of etchant gases such as NF3, CF4, and SF6. These gases interfere with the electron beam, as they get further excited and broken up by the incoming electrons. Such process is complicated by the radiative interactions, ionization, and the participation of admixed gases or substrate atoms. This grant aims at the elucidation of these overlapping processes by such combined diagnostics approaches of time-of-flight spectroscopy, mass spectrometry, and, if necessary, laser induced fluorescence. The evolvement of a reliable interaction model would be extremely useful to the silicon processing industries.