| abstract |
Ashing of an organic film from a substrate is carried out by providing a plasma comprising a gas or gas mixture selected from the following groups: (a) sulfur trioxide alone; (2) sulfur trioxide plus one supplemental gas; and (3) sulfur trioxide plus at least two supplemental gases. Any of the following gases may be employed as the supplemental gas: oxygen, ozone, hydrogen, nitrogen, nitrogen oxides, helium, argon, or neon. Also, a process is provided for forming a plasma in a reaction chamber from reactant gases containing sulfur trioxide. The process includes introducing the sulfur trioxide into the reaction chamber from a storage vessel through a delivery manifold by independently heating the storage vessel and the delivery manifold to a temperature sufficient to maintain the sulfur trioxide in its gaseous state or liquid state and by heating the reaction chamber to control the reaction rate of the sulfur trioxide and also control condensation of the sulfur trioxide to maintain a stable plasma state. |