Forming conductive vias using a light guide

Abstract

The present invention provides a process and a structure of forming conductive vias using a light guide. In an exemplary embodiment, the process includes providing a via in a base material in a direction perpendicular to a plane of the base material, applying a photoresist layer to an interior surface of the via, inserting a light guide into the via, exposing, by the light guide, a portion of thephotoresist layer to light, thereby resulting in an exposed portion of the photoresist layer and an unexposed portion of the photoresist layer, removing a portion of the photoresist layer, and platingan area of the via, where the photoresist has been removed, with a metal, thereby resulting in a portion of the via plated with metal and a portion of the via not plated with metal.

Description

technical field [0001] The present disclosure relates to conductive vias in printed circuit boards (PCBs), and more particularly, to the use of light guides to form conductive vias. Background technique [0002] Existing techniques for PCB via stub removal require either (a) machining (drilling, milling, etc.) or (b) a laser "drilling" process to remove the unwanted conductive portion of the via barrel. While both of these existing processes are successful in reducing through-hole stub lengths, they are prohibitively expensive, a significant source of manufacturing defects, rarely 100 percent successful, and most importantly, limit the density and complexity of high-speed PCBs . [0003] Numerous techniques exist for back-drilling and laser removal of PCB vias. Existing processes are extremely expensive, a significant source of manufacturing defects and, most importantly, limit the density and complexity of high-speed PCBs. Known methods include (a) machining methods to r...

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Problems solved by technology

Existing processes are extremely expensive, a significant source of manufacturi...

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