A Disposable and Self-Aligned 3-D Integrated Bio-Sensing Interface Module for CMOS Cell-Based Biosensor Applications

This letter presents a disposable, self-aligned, and die-level socketed 3-D integrated biosensing-interface module (BIM) for biosensing applications. The enabling technologies of the BIM include: 1) mechanically flexible interconnects (MFIs) that provide temporary electrical interconnections to enable disposability; 2) sapphire precision balls and positive self-alignmentstructures, which in combination with KOH-etched pits provide the BIM self-alignment capabilities; and 3) a clamped socket that temporarily provides the necessary force for the MFIs to form and maintain electrical contact with the underlying test die during testing. Repeated alignment measurements show that the alignment of the BIM to the biosensor varies little between uses, hence demonstrating that the biosensor system can maintain accurate alignment. In addition, four-point resistance measurements were taken after assembly indicating that temporary electrical connections were formed and maintained.