Laser fault injections induce transient faults into ICs by locally generating transient currents that temporarily flip the outputs of the illuminated gates. Laser fault injection can be anticipated or studied by using simulation tools at different abstraction levels: physical, electrical, or logical. At the electrical level, the classical laser fault injection model is based on the addition of current sources to the various sensitive nodes of CMOS transistors. However, this model does not take into account the large transient current components also induced between the VDD and GND of ICs designed with advanced CMOS technologies. These short-circuit currents provoke a significant IR-drop that contribute to the fault injection process. This paper describes our research on the assessment of this contribution. It shows through simulation and experiments that during laser fault injection campaigns, laser-induced IR-drop is always present when considering circuits designed with deep submicron technologies. It introduces an enhanced electrical fault model taking the laser-induced IR-drop into account. It also proposes a methodology that allows the use of the model to simulate laser-induced faults at the electrical level in large-scale circuits. On the basis of further simulations and experimental results, we found that, depending on the laser pulse characteristics, the number of injected faults may be underestimated by a factor of up to 2.4 if the laser-induced IR-drop is ignored. This could lead to incorrect estimations of the fault injection threshold, which is especially relevant to the design of countermeasure techniques for secure integrated systems.

中文翻译：

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激光故障注入过程中 IR 压降的重要性的仿真和实验证明

激光故障注入通过局部产生暂时翻转照明门输出的瞬态电流，将瞬态故障引入 IC。可以通过使用不同抽象级别的仿真工具来预测或研究激光故障注入：物理、电气或逻辑。在电气层面，经典的激光故障注入模型是基于向 CMOS 晶体管的各个敏感节点添加电流源。但是，该模型没有考虑采用先进 CMOS 技术设计的 IC 的 VDD 和 GND 之间也感应出的大瞬态电流分量。这些短路电流会引起显着的 IR 压降，从而导致故障注入过程。本文描述了我们对这一贡献的评估的研究。通过仿真和实验表明，在激光故障注入活动中，考虑采用深亚微米技术设计的电路时，总是存在激光诱导的 IR-drop。它引入了一个增强的电气故障模型，将激光引起的 IR 降考虑在内。它还提出了一种方法，该方法允许使用该模型在大规模电路中的电级模拟激光引起的故障。在进一步的模拟和实验结果的基础上，我们发现，根据激光脉冲特性，如果忽略激光诱导的 IR 降，注入故障的数量可能被低估高达 2.4 倍。这可能导致错误估计故障注入阈值，这与安全集成系统的对策技术设计尤其相关。