The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 10, 1990
Filed:
Jun. 10, 1985
Harold Lake, Sharon, MA (US);
Paul E Grandmont, Franklin, MA (US);
The Foxboro Company, Foxboro, MA (US);
Abstract
A process for making additive multilayer circuit boards uses separately designed and fabricated composite structures each consisting of a patterned conductive metal foil supported by a photo-processible insulating film. The composite is bonded foil pattern side down to the substrate or pre-existing multilayer structure and selected areas of the insulating film are removed down to underlying metal sites for electroless plating. All of the apertures in the insulating film are then electrolessly plated full of metal flush to the upper surface. Additional patterned composites are applied and plated up as desired to create blind vias and new conductor patterns layer by layer. In an alternate process a foil clad composite is bonded to an existing substrate foil side up. The insulating layer is selectively etched through windows photoetched in the foil layer. The voids in the insulator layer expose copper sites on the underlying composite. The voids are plated full of metal to form vias and the foil layer is photoetched to make a conductor pattern. The process is repeated to make a multilayer PWB.