Methods of forming a patterned metal film on a support
AssigneeWestern Electric Company, Inc.
InventorErnest W. Sawyer
Life of this patent
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Abstract
A printed circuit board is formed by forming a negative resist pattern over the surface of a substrate, etching the surface, sensitizing and catalyzing the surface, stripping the negative mask and catalytic layer thereover leaving a positive catalytic circuit pattern on the substrate and electrolessly plating copper over the catalytic image. A preferred variation of this method includes flash plating a thin porous electroless deposit over the catalyzed substrate prior to stripping the resist layer.
Claims2
A method of applying a patterned metal film onto a substrate comprising (1) applying a negative mask onto a surface of the substrate whereby portions of the surface are exposed in a positive pattern, (2) forming micropores in the positive pattern portions of the substrate surface, (3) sensitizing the positive patterned portions of the substrate and the negative mask to form thereon a catalytic species capable of catalyzing an electroless metal deposition, (4) electrolessly depositing a thin porous flash metal deposit having a thickness of from 0.003 to 0.020 mils onto the delineated catalytic species in the circuit pattern, (5) removing the negative mask and thereby the catalytic species and flash electroless metal deposit thereon to delineate the catalytic species and flash deposit in the positive pattern on the substrate surface, and (6) electrolessly depositing a metal onto the catalyzed positive pattern.
Dependencies are inferred from the claim text.