Design of Monitor and Protect Circuits against FIB Attack on Chip Security

As information security chips are more widely used in the field of information security, the security of chips becomes increasingly important, which has also been a hot research field of information security. With the advances in technology, a chip-invasive method of attack which uses laser or focused ion beam (FIB) to change the chip's internal signal line, and then probe the chip's secret information with the electron microprobe, becomes a serious threat to information security chip. Such an attack makes the shielding metal wire an effective mean to improve chip security. The protection circuit module monitoring the shielding metal line is to ensure the layer of the metal wire is undamaged, in order to ensure that the chip has not been attacked by laser or FIB. This paper studies the design and implementation of Monitor and Protect Circuits (MPC) based on RC delay, which monitor if the shielding metal wires are damaged. The circuit is designed in SMIC0.18um CMOS process and an entire layout is completed. The gate count of MPC is about 642, which is 2.9% of that of AES. And its power consumption is about 81uw.