Hardware Trojan Detection Using Backside Optical Imaging

The high cost of integrated circuit chip production has driven more and more chip design companies to use overseas production services. Since the integrated circuit production cannot be closely monitored, the security of integrated circuit chips has become a major concern. Hardware Trojan (HT) insertion is one type of the hardware attack. HTs are extremely stealthy due to their small sizes and low triggering rates. HTs inserted during manufacturing can have minimum impact on the timing and power. In fact, this impact can be smaller than the timing and power variations caused by the process variations. Therefore, these HTs cannot be easily detected using traditional electrical methods. In this article, we propose a novel optical method, where we image the integrated circuit chip from the backside. Our method, can easily detect any replacements, modifications, or rearrangements of fill cells or functional cells for HT insertion. We use a noise-based detection method to achieve high HT detection rates in different testbenches. To further improve the robustness of our method, we strategically place high reflectance fill cells in the designs. Our approach provides high-resolution, nondestructive, and rapid means to detect HTs inserted during fabrication. We evaluate our approach using various hardware blocks where the HTs can occupy less than 0.1% of the total area or consist of fewer than three gates. In addition, we analyze our method with various magnitudes of noise, process variations, detection window sizes, and resolutions.