A double-sided, single-chip integration scheme using through-silicon-via for neural sensing applications

Abstract

We present a new double-sided, single-chip monolithic integration scheme to integrate the CMOS circuits and MEMS structures by using through-silicon-via (TSV). Neural sensing applications were chosen as the implementation example. The proposed heterogeneous device integrates standard 0.18 μm CMOS technology, TSV and neural probe array into a compact single chip device. The neural probe array on the back-side of the chip is connected to the CMOS circuits on the front-side of the chip by using low-parasitic TSVs through the chip. Successful fabrication results and detailed characterization demonstrate the feasibility and performance of the neural probe array, TSV and readout circuitry. The fabricated device is 5 × 5 mm(2) in area, with 16 channels of 150 μm-in-length neural probe array on the back-side, 200 μm-deep TSV through the chip and CMOS circuits on the front-side. Each channel consists of a 5 × 6 probe array, 3 × 14 TSV array and a differential-difference amplifier (DDA) based analog front-end circuitry with 1.8 V supply, 21.88 μW power consumption, 108 dB CMRR and 2.56 μVrms input referred noise. In-vivo long term implantation demonstrated the feasibility of presented integration scheme after 7 and 58 days of implantation. We expect the conceptual realization can be extended for higher density recording array by using the proposed method.

Neural Interfaces for Intracortical Recording: Requirements, Fabrication Methods, and Characteristics

“…(E) All-silicon wire electrodes fabricated by combination of wet and dry etching processes (Pei et al, 2014 ). (F) TSV-integrated silicon microneedle array (Chang et al, 2015 ).…”

“…The volume of the whole system can be significantly decreased by employing single-chip integration scheme. This can be achieved by the same substrate-integration and through-silicon-vias connectivity (Chou et al, 2014 ; Huang et al, 2014 ; Chang et al, 2015 ). Full system integration was achieved for UEAs integrated with data processing units, power supply, and telemetry link in multi-level hybrid assembly containing flip chip bonding, reflow soldering, and adhesive bonding to form compact standalone package (Kim et al, 2009 ).…”

Low-power low-area techniques for multichannel recording circuits dedicated to biomedical experiments

“…The main IC parameters are very attractive for systems requiring recordings of different biomedical signals. The presented recording channel was compared to other works [27][28][29][30] in terms of its current consumption and area occupation.…”

2.5D Heterogeneously Integrated Microsystem for High-Density Neural Sensing Applications

“…Many neural sensing microsystems have been proposed to provide small form factor and biocompatible properties, including stacked multichip [6]- [8], microsystem with separated neural sensors [9]- [11], monolithic packaged microsystem [12] and through-silicon-via (TSV) based double-side integrated microsystem [13], [14]. These heterogeneous biomedical devices compose of sensors and CMOS circuits for biopotential acquisition, signal processing and transmission.…”

“…However, the weak signals detected from sensors in [6]- [12] have to pass through a string of interconnections and interfaces to the CMOS circuits by wire bonding. The detailed comparisons of these schemes have been analyzed in [14]. In view of this, TSV-based double-side integration [13], [14] uses TSV arrays to transfer the weak signals from -probe arrays to CMOS circuits for reducing noises.…”