The United States of America As Represented by the Administrator of the

The United States of America As Represented by the Administrator of

Narcinda R Lerner

Theodore J Wydeven

Domenick E Cagliostro

A method for etching or removing polymers, photoresists, and organic contaminants from a substrate is disclosed. The method includes creating a more reactive gas species by producing a plasma discharge in a reactive gas such as oxygen and contacting the resulting gas species with a sacrificial solid organic material (13A) such as polyethylene or poly(vinyl fluoride), producing a highly reactive gas species, which in turn etches the starting polymer, organic contaminant, or photoresist (13). The sample to be etched is located away from the plasma glow discharge region (11) so as to avoid damaging the substrate by exposure to high-energy particles and electric fields encountered in that region. Greatly increased etching rates are obtained. This method is highly effective for etching polymers such as polyimides and photoresists that are otherwise difficult or slow to etch downstream from an electric discharge in a reactive gas.

Etching method for photoresists or polymers

This invention relates to a method of carbonizing polyacrylonitrile fibers (PAN fibers) by exposing the fibers at an elevated temperature to an oxidizing atmosphere, then exposing the oxidized fibers to an atmosphere of an inert gas such as nitrogen containing a carbonaceous material such as acetylene. The fibers are preferably treated with an organic compound, for example benzoic acid, before the exposure to an oxidizing atmosphere. The invention also relates to the resulting fibers. The treated fibers have enhanced tensile strength.

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Woodside, CA, United States of America

Narcinda R Lerner