An integrated high-precision probe system for near-field magnetic measurements on cryptographic LSIs

This paper presents a fully integrated RF magnetic probe with a multi-stage low-noise amplifier (LNA) in a 0.18-μm CMOS process to measure and analyze magnetic near-field map on cryptography LSI chips. A 3-stage controllable-gain differential LNA is integrated with a 100μm×100μm pickup coil whose underneath Si-substrate area is sputtered away by a Focused-Ion-Beam (FIB) technique to enhance the coil´s performance. A high and controllable-gain LNA with self-bias cascode structure is also proposed for the last-stage amplifier. Post-layout simulated total gain of the LNA is achieved up to 63-dB at 17.37 MHz by HSPICE. High-precision mechanical scanning and monitoring system for the probe is implemented in this work. The first evaluation of the probe performance is performed by measuring the emission of a 200-μm-width micro-strip-line through the probe output and the high-precision scanning system. Then, the probe and the system are applied to measure and built 7mm×9mm 2D-distributed magnetic-field maps of a field-programmable gate array (FPGA) operating with a 24-MHz clock on an Advanced-Encryption-Standard (AES) encryption core.