In contrary to multi-layer circuits traditionally manufactured in standard PCB (Printed Circuit Board) technology, this article specifically describes a technology which combines the benefits of Thin Film Technology processes with methods from the PCB technology. Noble metals for the formation of conductor lines combined with laminated LCP (Liquid Crystal Polymer) polymers as substrate and insulator materials allow the formation of multi-layer circuits with only a very limited number of different participating materials. Such types of circuits can be made completely out of biocompatible materials and thus, are excellently suitable for applications inside the human body.
This article will describe the general aspects of this technology and discuss the process flow for the manufacturing of thin film based LCP multi-layer circuits. Characterization results from stability examinations of these circuits in buffered saline solution are shown and discussed to prove the performance of the manufactured circuit structures.