Chemical milling process

Abstract

Abstract IMPROVED CHEMICAL MILLING PROCESS AND RESULITING PRODUCT UTILIZING PHOTOGRAPHICALLY EXPOSED AN DEVELOPED RESIST DESIGNS ON A METAL PLATE WITH UNEXPOSED PORTIONS OF THE RESIST EMULSION DISSOLVED AWAY, CHARACTERIZED BY A BAKING STEP OR STEPS HARDER THAN CONVENTIONAL, A SERIES OF CONTROLLED ETCHING TREATMENT ON ONE SIDE, AND A SERIES OF DIFFERENTLY CONTROLLED HARSHER ETCHING TREATMENT ON THE OTHER SIDE, RESULTING IN A DESIGN OF SUSPENDED METAL AREAS HAVING SUBSTANTIALLY FLAT PLANE OR SLIGHTLY CONCAVE ETCHED EDGES AS DISTINGUISHED FROM SHOULDERS OR RIDGES. A PARTICULAR APPLICATION IS FOR PRODUCING ELECTRICAL CIRCUITRY UTILIZING A METALLIC PLATE CONTAINING IDENTICAL CIRCUIT DESIGNS ON BOTH SIDES FORMED OF THE PHOTOGRAPHIC ETCH RESIST, AND UPON REMOVAL OF THE UNWANTED METAL BY THE DIFFERENTIAL ETCHING STEPS ON OPPPOSITE SIDES OF THE PLATE, OBTAINING AN INTEGRATED CIRCUIT STRUCTURE WITH CONDUCTORS RESPONDING TO THE ETCH RESISTANT PATTERN AN IN CROSS SECTION BEING SUBSTANTIALLY RECTANGULAR WITH PARALLEL TOP AND BOTTOM AND PARALLEL SIDES, OR WITH THE SIDES VERY SLIGHTLY CONCAVED, THUS PROVIDING ADEQUATE SURFACES ON THE SIDES FOR ATTACHMENT OF WIRES WELDING.

Inventors

• 👤 Gregory A Duffy

Bibliographic Details