By using metal blocks as the protective coating, placing the sensitive signals in last but second metal (LSM), integrating a low-cost one-time programming (OTP) cell in each PUF unit, the proposed switched-capacitor (SC) PUF can both provide sensitive anti-invasive-attack protective coating and stable key for the security chip. Moreover, the circuit parameters and the layout implementation of the SC PUF unit are all compatible with other digital standard cells, which greatly facilitates the integration of SC PUF unit in the security chip by using digital design flow when its function, timing, power, and layout views are characterized using commercial timing and layout extraction tools. The anti-invasive-attack ability, stability, and digital design flow compatibility of the proposed SC PUF standard cell are verified in a security chip by using a standard 0.18- $\mu \text{m}$ CMOS process. The measured bit error rate, bias, average intra-die HD, and average inter-die HD of output keys after OTP is <10 ⁻⁴ , 46.72%, 0%, and 50.38% respectively. Finally, the failed probing and destruction attack attempts to the coating also verify the invasive-attack-resistant property of the proposed SC PUF standard cell. With the help of SC PUF standard cell, the whole security chip can easily obtain stable keys and sensitive anti-invasive-attack ability by using digital design flow.

中文翻译：

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用于密钥生成和抗入侵攻击保护的 SC PUF 标准单元

通过使用金属块作为保护涂层，将敏感信号放在最后的第二个金属 (LSM) 中，在每个 PUF 单元中集成一个低成本的一次性编程 (OTP) 单元，所提出的开关电容器 (SC) PUF 可以两者都为安全芯片提供灵敏的防入侵保护涂层和稳定的密钥。而且，SC PUF单元的电路参数和布局实现均兼容其他数字标准单元，在功能、时序、功率、布局视图的特点是使用商业时序和布局提取工具。抗入侵能力强，稳定性好， $\mu \text{m}$ CMOS工艺。OTP后输出密钥的测量误码率、偏差、平均芯片内HD和平均芯片间HD分别为<10 ^-4 、46.72%、0%和50.38%。最后，对涂层的探测和破坏攻击尝试失败也验证了所提出的 SC PUF 标准单元的抗侵入性攻击特性。整个安全芯片借助SC PUF标准单元，通过数字化设计流程，轻松获得稳定的密钥和灵敏的抗入侵攻击能力。