Westinghouse Electric Corporation

Maurice B Shamash

Frank A Lindberg

Stephen G Konsowski

Seymour J Ponemone

There is disclosed a method for producing in thick (0.005 inches) polyimide films or sheets, openings, or windows across each of which an electrical conductor, such as copper or aluminum extends. The windows may be of substantial dimensions typically 0.05 inches by 0.1 inches. The conductor is of substantial thickness of about 0.0008 to 0.001 inches. The method is practiced with a sheet in which holes have been preformed. The sheet is coated with the conductor on both surfaces by being rotated in a stream of vapor of the conductor produced by impinging an electron beam (typically at 10 KV and 300 milliamperes) on a block of the conducting material. As the sheet is rotated in the stream of vapor, the walls of the holes as well as the surface of the sheet are coated with a conductor. Photoresist is then deposited on both coated surfaces of the sheet and in the holes and is exposed under masks and developed so as to expose the conducting coating on each surface in the areas of the windows. The exposed coating is then removed with an acid etchant while the remainder of the surfaces including the coating on the walls of the holes remain protected by the developed photoresist. The polyimide in the areas of the windows is thus exposed. The exposed polyimide is then removed by hydrazine leaving windows in each surface with conductors extending across the windows on the respective opposite surfaces.

Formation of openings in dielectric sheet

There is disclosed a method for producing in thick (0.005 inches) polyimide films or sheets, openings, or windows across each of which an electrical conductor, such as copper or aluminum extends. The windows may be of substantial dimensions typically 0.05 inches by 0.1 inches. The conductor is of substantial thickness of about 0.0008 to 0.001 inches. The sheet is coated with the conductor on both surfaces by being rotated in a stream of vapor of the conductor produced by impinging an electron beam (typically at 10 KV and 300 milliamperes) on a block of the conducting material. Photoresist is then deposited on both coated surfaces of the sheet and exposed under masks and developed so as to expose the conducting coating on each surface in the areas of the windows. The exposed coating is then removed with an acid etchant while the remainder of the surfaces remain protected by the developed photoresist. The polyimide in the areas of the windows is thus exposed. The exposed polyimide is then removed by hydrazine leaving windows in each surface with conductors extending across the windows on the respective opposite surfaces.

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Randallstown, MD, United States of America

Maurice B Shamash