Process for fabricating circuit assemblies using electrodepositable dielectric coating compositions

Abstract

Provided is a process for forming metallized vias in a substrate including the steps of (I) applying to an electroconductive substrate an electrodepositable coating composition onto all exposed surfaces of the substrate to form a conformal dielectric coating; (II) ablating a surface of the dielectric coating to expose a section of the substrate; (III) applying a layer of metal to all surfaces to form metallized vias in the substrate. Also disclosed are processes for fabricating a circuit assembly which include the application of an electrodoepositable coating composition onto exposed surfaces of the substrate / core to form a conformal dielectric coating thereon. The electrodepositable coating composition includes a resinous phase dispersed in an aqueous phase, where the resinous phase has a covalently bonded halogen content of at least 1 percent by weight. The dielectric coating derived therefrom has a low dielectric constant and low dielectric loss factor.

Description

technical field [0001] The present invention relates to methods of forming metallized vias and preparing multilayer circuit assemblies including dielectric coatings, particularly dielectric coatings applied by electrodeposition. Background technique [0002] Electrical components such as resistors, transistors and capacitors are commonly mounted on circuit panel structures such as printed circuit boards. Circuit panels generally comprise a generally planar sheet of dielectric material with electrical conductors disposed on one or both of the planar major surfaces of the sheet. The conductor is generally made of metallic material such as copper, etc., and is used to connect electrical components mounted on a circuit board. When the conductors are on both major surfaces of the panel, the panel may have hole conductors extending through holes (or vias) in the dielectric layer to connect conductors on opposite surfaces. Multilayer circuit panel assemblies have heretofore been ...

AI Technical Summary

Problems solved by technology

[0011] US4,601,916 proposes that the direct deposition of an insulating coating onto the metal wall portion of the hole can form a uniform film of resin on the hole wall without thinning of the coating at the top and bottom edges of the hole, and subsequent metal deposition will not interfere with Hole wall adhesion, further electrical insulation performance is not enough