CSST: Preventing distribution of unlicensed and rejected ICs by untrusted foundry and assembly

The globalization of the semiconductor design and fabrication industry (also known as the horizontal business model) has led to many well-documented issues associated with untrusted foundries and assemblies, including IC overproduction, cloning, and the shipping of improperly or insufficiently tested chips. Besides the loss in profits to Intellectual Property (IP) owners, such chips entering the supply chain can have catastrophic consequences for critical applications. We propose a new Secure Split-Test (SST) scheme called the Connecticut SST (CSST) in which the IP owner takes full control over testing. In CSST, each chip and its scan chains are locked during testing, and only the IP owner can interpret the locked test results and unlock passing chips. The new SST can prevent overproduced, defective, and cloned chips from reaching the supply chain. The proposed method considerably simplifies the communication required between the foundry/assembly and the IP owner compared to the original version of the SST. The results demonstrate that our new technique is more secure than the original and has lower communication overheads.