The Study of TSV-Based μ-Probe Array for High Quality Neural Signal Recording

• Main Authors: Chou, Lei-Chun, 周雷峻
• Other Authors: Chiou, Jin-Chern
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/r2xpf7

博士 === 國立交通大學 === 電控工程研究所 === 102 === In this thesis, two generation of μ-probe arrays with TSV technology are presented. Both these μ-probe arrays can be used in bio-signal recording to explore operation function of a brain. In generation I, a novel through-silicon-via-based double-side bio-signal recording device is demonstrated and investigated. Bio-signal probes providing stable observation with high quality signals are crucial for understanding how the brain works and how the neural signal transmits. Due to the weak and noisy characteristics of bio-signals, the connected interconnect length between the sensor and CMOS has significant impact on the bio-signal quality. In addition, long interconnections with wire bonding technique introduce noises and lead to bulky packaged systems. This thesis presents an implantable through-silicon via (TSV) technology to connect sensors and CMOS devices located on the opposite sides of the chip for brain neural sensing applications. With the elimination of traditional wire bonding and packaging technologies, the quality of bio-signal can be greatly improved. Moreover, a low-cost and high yield fabrication process for through-silicon-via (TSV)-based bio-signal packaging also presents in this thesis. In measurement results, device impedance is 1.2 KΩ /1 KHz, and total chip size is only 5 mm × 5 mm. Moreover, the rat survival rate increases, owing to the small device size. Additionally, each channel has 3 × 8 TSV arrays, and 16 channels die contains 30 × 16 microprobes, and 4 channels die contains 140 × 4 microprobes. Furthermore, different channels can acquire different neural cell signals, ultimately benefiting neural-signal analysis. In generation II, a 2.5D integration with TSV-inside μ-probes and block diagrams of the bio-sensing microsystem is presented. This microsystem composes of TSV-inside μ-probes, 4 dies and 1 interposer. The measured impedance is 0.17Ω with phase of -0.5° at 1KHz. Total area of μ-probe array chip is 5 mm × 5 mm. One TSV-inside μ-probe signifies one channel. Thus, there are 24 × 24 channels in a chip. In this thesis, two generation integrated bio-signal recorders with μ-probe array and TSV technology for bio-sensing applications are presented. Integration with TSV and MEMS technology achieves high density and high channel resolution brain signal recorder. The brain signal recorder can be helpful for brain function investigation and neural prostheses realization.