Westinghouse Electric Corporation

United States of America As Represented by the Secretary of the Air Force

Richard D Blaugher

John Xavier Przybysz

Richard H Hopkins

Robert L Kolek

Joseph Buttyan

This is an improved method for providing silicon dioxide with openings which expose contact pad areas for connections to superconductor in the preparation of superconducting integrated circuits. It relates to the type of method which utilizes depositing of a silicon dioxide film on a substrate (including over superconductor conductor patterns on the substrate surface), placing a resist film on the silicon dioxide film, patterning the resist film to expose portions of the silicon dioxide, and reactive ion etching the exposed portions of the silicon dioxide film to expose contact pad areas of superconductor. The improvement utilizes an etchant gas consisting essentially of 50-95 volume percent nitrogen trifluoride and 5-50 volume percent rare gas (preferably about 77 volume percent nitrogen trifluoride, with argon or neon or mixtures thereof as the rare gas) for the reactive ion etching of the exposed portions of the silicon dioxide film. Thus a carbon-containig etchant is not used and polymer by-products of the etching process are essentially completely avoided.

Selective silicon dioxide etchant for superconductor integrated circuits

A film is disclosed which will accommodate high shear strain in a rigidly supported epoxy impregnated Nb.sub.3 Sn superconducting coil (SCC). In a generator application the SCC is subjected to a combined load due to differential thermal contraction, magnetic, and centrifugal forces. These strains could lead to coil fracture and resulting degradation of the field and current-carrying properties. A low modulus material at the interface between the SCC and support structure will reduce or distribute the shear strain to an acceptable level, i.e., no degradation in current carrying properties. Two film materials, polyethylene terephthalate Mylar (DuPont Chemical) and polycarbonate Makrofol KG (Mobay chemical) are disclosed as suitable damping or interface films. An adhesive such as the polyurethane Bostik 7070 is used for affixing the film to the winding surface.

Low modulus damping film

This is a method of producing grain-oriented, iron sheet for electrical applications. The process utilizes relatively pure iron which is deoxidized to have less than 50 ppm of oxygen. The carbon content is adjusted to 0.01-0.02 wt. % (preferably 0.010-0.015 wt. %). The material is hot rolled at a temperature of at least 800.degree. C., cold rolled with a 60-75% reduction, recrystallized in an non-oxidizing atmosphere at 700.degree.-820.degree. C., cold rolled a second time with a 60-75% reduction, annealed at 700.degree.-825.degree. C. in a non-oxidizing atmosphere and cold rolled a third time with a 60-75% reduction and final annealed at 850.degree.-900.degree. C. for 50-200 hours in a reducing atmosphere.

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Pittsburgh, PA, United States of America

Richard D Blaugher