Qualification Methodology for the Double Side Printed Substrate for Hybrid Microcircuits Application

Abstract

Hybrid Microcircuits (HMCs) are always preferred over discrete versions due to small size, less weight, better performance and high reliability for space applications. Double side printed substrates realized using Thick film screen printing and Printed Through Hole (PTH) processes are being used in HMCs in order to achieve further miniaturization. This article details the newly developed innovative Thick film process technology involving drilling of holes and filling the through hole with gold conductive paste to connect the front and rear side of conductor patterns on an alumina substrate. The biggest challenge in the realization of double side printed substrates is creating multiple via holes and filling them with conductor paste. In addition, the limited ability to achieve substrate integration and uniformity pose additional challenges that require optimization of process parameters. A comprehensive test plan created to qualify this innovative method in terms of quality and reliability suitable for the aerospace industry is also presented.