Split Manufacturing in Radio-Frequency Designs

With the globalization of integrated circuit (IC) design flow and the outsourcing of chip fabrication service, intellectual property (IP) piracy and malicious logic insertion become main security threats to tamper hardware infrastructures. While most of the protection methods are dedicated for digital circuits, we try to protect radio-frequency (RF) designs which are more likely to be IP piracy victims. For the first time, we apply the split manufacturing method in RF circuit protection. Three different implementation cases are introduced for security and design overhead tradeoffs, i.e., the removal of the top metal layer, the removal of the top two metal layers, and the design obfuscation dedicated for RF circuits. We also develop a quantitative security evaluation method to measure the protection level of RF designs under split manufacturing. Finally, a class-AB power amplifier is used for demonstration through which we prove that: 1) the removal of top metal layer or top two metal layers can provide high-level protection for RF circuits with lower request to the domestic foundries; 2) design obfuscation method provides highest level of circuit protection, though at the cost of design overhead; 3) split manufacturing is more suitable to RF designs than to the digital circuits and it can effectively improve hardware tamper resistance and reduce IP piracy in the untrusted off-shore foundries. Keywords-Hardware Tamper Resistance, Hardware Trust, IP Piracy, Power Amplifier, RF Circuits, Split Manufacturing