Plasma-based process for production of F and HF from benign precursors and use of the same in room-temperature plasma processing

US10854441B2 · kind B2 · utility

Assignee

• The Government of the United States of America, as represented by the Secretary of the Navy · US

Inventors

• David R. Boris · Washington, US
• Scott G. Walton · Fairfax, US

Key dates

• Filing date: Jun 4, 2019
• Grant date: Dec 1, 2020
• Expiry date: Jun 4, 2039

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01J2237/335
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

Methods and apparatuses for the production of HF in an electron-beam generated plasma. A gas containing fluorine, hydrogen, and an inert gas such as argon, e.g., Ar/SF6/H2O or Ar/SF6/NH3 flows into a plasma treatment chamber to produce a low pressure gas in the chamber. An electron beam directed into the gas forms a plasma from the gas, with energy from the electron beam dissociating the F-containing molecules, which react with H-containing gas to produce HF in the plasma. Although the concentration of the gas phase HF in the plasma is a very small fraction of the total gas in the chamber, due to its highly reactive nature, the low concentration of HF produced by the method of the present invention is enough to modify the surfaces of materials, performing the same function as aqueous HF solutions to remove oxygen from an exposed material.