Epoxy-based aqueous-processable photodielectric dry film and conductive ViaPlug for PCB build-up and IC packaging

DuPont formulated a new generation of photoimageable permanent resists and conductive ViaPlug polymer to be used as building blocks for sequential build-up of printed circuit boards (PCB's), multichip module-laminates (MCM-Ls), and plastic integrated circuit (IC) packages. The buzzwords for these structures are high density interconnection structures (HDIS) and microvias. The conventional method of making PCB's and MCM-Ls is a sequential lamination of innerlayer cores or interplanes, followed by at least one mechanical drilling. In this paper we will discuss a new approach of using semi-additive plating which means starting with a multilayer core, mechanically drilling for through hole connection, filling the through-hole with conductive ViaPlug, then adding layers of dielectric to make blind or buried vias for interconnection and routing of circuits, and heat dissipation. The paper will discuss the challenges in each application, relevant industry specifications for each application, and the dielectric and conductor materials properties to meet the challenges. From the viewpoint of technology choices, we will compare photoimaging versus laser ablation and plasma etching. Lastly, we will discuss our reliability data developed internally and in conjunction with several consortia.