18.6 2.5D heterogeneously integrated bio-sensing microsystem for multi-channel neural-sensing applications

Heterogeneously integrated and miniaturized neural sensing microsystems for accurately capturing and classifying signals are crucial for brain function investigation and neural prostheses realization [1]. Many neural sensing microsystems have been proposed to provide small form-factor and biocompatible properties, including stacked multichip [2, 3], microsystem with separated neural sensors [4], monolithic packaged microsystem [5] and through-silicon-via (TSV) based double-side integrated microsystem [6]. These heterogeneous biomedical devices are composed of sensors and CMOS circuits for biopotential acquisition, signal processing and transmission. However, the weak signals detected from sensors in [2-5] have to pass through a string of interconnections to the CMOS circuits by wire bonding. In view of this, TSV-based double-side integration [6] uses TSV arrays to transfer the weak signals from μ-probe arrays to CMOS circuits for reducing noises. Nevertheless, the double-side integration requires preserving large area for separate μ-probe arrays and TSV arrays, and the TSV fabrication process may induce damage on CMOS circuits.