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Trisodium Phosphate Potassium Permanganate Etchant

IP.com Disclosure Number: IPCOM000082993D
Original Publication Date: 1975-Mar-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Gardner, TR: AUTHOR [+2]

Abstract

In a gas panel assembly, individual conductor arrays of chrome-copper-chrome intersections of which identify the cell locations are formed on glass substrates, the lower chrome layer providing adhesion to the surface of the glass substrate and the upper chrome layer serving to protect the intermediate copper conductor layer from attack by the dielectric glass frit, which is deposited over the conductor array.

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Trisodium Phosphate Potassium Permanganate Etchant

In a gas panel assembly, individual conductor arrays of chrome-copper- chrome intersections of which identify the cell locations are formed on glass substrates, the lower chrome layer providing adhesion to the surface of the glass substrate and the upper chrome layer serving to protect the intermediate copper conductor layer from attack by the dielectric glass frit, which is deposited over the conductor array.

The three layers are deposited over the glass substrates in sequence, a layer of resist then deposited and exposed through a desired pattern, the pattern developed and the exposed resist removed by etching. Since the etchant attacks the photoresist, a postbake process of the photoresist at 130 degrees for one- half hour is required to harden the resist before etching, which, in turn, renders the resist inactive to further exposure by ultra-violet light and makes its removal by a rather lengthy stripping process difficult.

An etchant for chrome composed of 230 grams trisodium phosphate and 60 grams of potassium permanganate per liter of solution has some distinct advantages over the conventional etchant material. By using this etchant, the photoresist postbake step may be eliminated from the fabrication process.

If the photoresist is not postbaked, it remains photoactive and may be reexposed in further process steps. This could be of advantage in working with multilayer configurations, which may require diff...