A Novel Assembly Method for Silicon-Based Neural Devices

Abstract

This paper reports on a novel interconnection technology for silicon-based neural devices used in extracellular recording. It is based on a flip-chip bonding process establishing the electrical connection of the silicon specimen and a highly flexible polymer cable via electroplated contact structures. This process makes possible the parallel connection of multiple bonding pads with high integration density. By the integration of a structurable fluoropolymer on the cables as an adhesion layer the mechanical connection is improved simultaneously. Further, the adhesion layer inherently encapsulates the bonding sites and allows omitting the application of an additional underfill. Test structures were characterized with respect to the electrical and mechanical reliability of this interconnection approach. The storage in Ringer’s solution for 12 days minimally affected the cable connection and its inherent encapsulation capability. Furthermore, a neural device was assembled with this technology and its capability for intracortical neural recording was demonstrated.