PREATS: Passive RFID-Based Embedded Anti-Tampering Sensor for Authentication in Semiconductor Supply Chain

This article describes a passive RFID-based embedded anti-tampering sensor (PREATS) for integrated chips (ICs) authentication in the semiconductor supply chain. The sensor has <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.7\times 2.6\times 2.5$ </tex-math></inline-formula> mm3 (0.024cc) dimensions, significantly reducing the volume of our previous unintegrated detector for being fit into IC packages. The PREATS includes a pyroelectric energy harvester (PEH), a high-overtone bulk acoustic resonator (HBAR), a shock switch for sensing accelerations beyond 40 g, and an ultrawideband (UWB) chip antenna for wireless interrogation. The HBAR works as a radio frequency identification (RFID) tag connected to a chip antenna, which can be wirelessly interrogated due to the HBAR’s high quality factor (Q) at 3.1 GHz (with f<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\cdot ~{Q} \gt 10^{{13}}$ </tex-math></inline-formula> Hz) before a tampering activity, which involves temperature elevation for desoldering followed by mechanical banging (beyond 40 g) for detaching ICs from printed circuit boards (PCBs). A lithium-tantalate-based PEH produces a large voltage and charge (due to the temperature rise) and delivers them to the HBAR during the mechanical banging (as the shock switch connects the PEH to the HBAR), creating a permanent short circuit between the top and bottom electrodes of HBAR that lowers the HBAR’s Q by several factors. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.2\times 0.5\times 1$ </tex-math></inline-formula> mm3 PEH delivers peak voltage and charge of 128 V and 8 nC, respectively, when it experiences 250 °C from a hot gun and a switch connects the PEH to a 10-M<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> resistor (emulating an HBAR). The PEH is empirically shown to form a stable metallic path from the top and bottom Al electrodes through the AlOx insulating layer, creating a stable electrical leakage path in the HBAR, which suppresses acoustic wave generation through the HBAR’s piezoelectric ZnO layer. A wireless interrogation is demonstrated through an interrogator antenna connected to a vector network analyzer (VNA) working as a wireless interrogator for a PREATS chip.