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:
Feb. 02, 1993
Filed:
Jul. 01, 1991
Prosanto K Mukerji, Schaumburg, IL (US);
Russell Mallen, Glen Ellyn, IL (US);
George Demet, Arlington Heights, IL (US);
Harry Fuerhaupter, Villa Park, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A method for producing a coating composed of an electroless metal plate, such as a copper plate, tightly bonded to a polyimide layer comprises a multi-step cure of the polyimide layer carried out in combination with a palladium-catalyzed electroless deposition process. A solution of a polyamic acid compound that is the precursor for the desired polyimide resin in a vaporizable solvent is applied to a substrate and heated preferably to temperature below 250.degree. C., to form a soft-cured polyimide film. The film is immersed in an aqueous palladium-tin colloidal suspension to deposit the colloidal particles thereon, which particles are then activated to form palladium nuclei dspersed on the surface. The soft-cured film is then heated, preferably above about 250.degree. C., to vaporize residual solvent and form a hard-cured polyimide layer having the palladium nuclei dispersed on the surface. The hard-cured layer is immersed in an electroless metal plating solution, whereupon the palladium nuclei catalyze deposition of the metal to form a continuous plate. In one aspect of the method, the metal-clad layer is further heated between about 350.degree. C. and 450.degree. C. to final cure the polyimide. It is found that the plate of the coating formed by this multi-cure method strongly adheres to the polymer layer to permit extended deposition and thereby form a relatively thicker plate without catastrophic separation from the polymer.