Physical Sciences Inc. (PSI) proposes to develop a high flux, high velocity (3 to 8 km/s) chlorine atom beam for etching of semiconductors. Conventional dry etching systems are based on ion-assisted processes that can lead to device damage and degradation. Neutral chlorine beam etching systems are under development but are limited to low energies (< 1 eV) or higher energies (> 100 eV). Low energy systems show significant under- cutting and high energy beams cause substrate damage. PSI will develop an atomic chlorine beam to operate in an intermediate en- ergy regime, 1 to 10 eV. The proposed effort is based on the fast atom sample tester (FAST) technology developed at PSI. Atomic oxygen (1 to 10 eV) produced using FAST technology exhibits a strong correlation between atom energy and surface reactivity with graphite. The data indicate an increase in first-collision reaction probability, with beam velocity, which is critical to achieving highly anisotropic etching. At the highest Cl-atom beam energies available from the FAST source, substrate damage is energetically unfavorable.
