Patent ID: 6706464
Filing Date: 2004-03-16
Classification: G03F,H05K,Y10T

Abstract:
A method of fabricating a circuitized structure comprising the steps of:a. providing a circuitized substrate; b. applying a photoimagable dielectric film to the circuitized substrate, wherein the dielectric film is an epoxy resin system comprising: i. from about 5% to 80% of phenoxy polyol resin which is the condensation product of epichlorohydrin and bisphenol A, having a molecular weight of from about 40,000 to 130,000; ii. from about 0% to 90% of an epoxidized multifunctional bisphenol A formaldehyde novolac resin having a molecular weight of from about 4,000 to 10,000; iii. from 20% to 50% of a diglycidyl ether of bisphenol A having a molecular weight of from about 600 to 2,500; iv. less than 15% of a cationic photoinitiator; v. from about 15% to about 35% liquid epoxy resin, having a molecular weight of from about 200 to about 600; and VI. from 0% to about 30% of a rheology modifier, and less than about 3% solvent; c. photoimaging said dielectric film to form photoimaged vias therein; d. plating circuitry on, and adherent to, the photoimaged dielectric film, at least one circuit on the photoimaged dielectric film being electrically connected to the circuitization on the substrate through said at least one via, and e. curing said photoimaged dielectric film.