Bio-signal probes that provide stable observation with high-quality signals are crucial for understanding how the brain works and how the neural signal transmits. Because bio-signals are weak and noisy, the length of the string connecting the sensor and Complementary Metal-Oxide-Semiconductor (CMOS) circuit significantly impacts biosignal quality. The collected weak signals from the sensor must pass through a series of interconnections and interfaces that introduce noise and lead to bulky packaged systems. This work uses through-silicon via (TSV) technology to connect the μ-probe array bio-sensor and CMOS circuit located on opposite sides of a chip for brain neural sensing applications. With the elimination of wire bonding and the reduction of the soldering, bio-signal quality can be significantly improved.