TSV-based current probing structure using magnetic coupling in 2.5D and 3D IC

Abstract

Simultaneous switching noise (SSN) is caused by the simultaneous switching of a group of I/O drivers, and is proportional to the total inductance and the rate of change of the switching current. This often leads to signal distortion and degradation of signal and power integrity of systems. Furthermore, with the continuously decreasing operating voltage, susceptibility to SSN keeps on increasing and it becomes increasingly challenging to achieve high performance interfaces. Therefore, it is highly important to perform SSN analysis in order to accurately investigate the noise and timing margin of the devices under test; hence, it is important to know the exact amount of switching current drawn by the ICs. In this paper, we propose TSV-based current probing structure using magnetic coupling, named TSV-based Current Probe (TCP). By capturing the magnetic flux induced by the injected current and processing it through a series of reconstruction steps, we can obtain the original current waveform of interest. Through a series of simulations in frequency and time domains, we verify the performance of the proposed probing structure, TCP. Lastly, TCP is fabricated using TSV fabrication techniques and measured for experimental verification.