Detecting Recycled SoCs by Exploiting Aging Induced Biases in Memory Cells

The rise of recycled ICs being sold as new through the global semiconductor supply chain is a serious threat due to their inferior quality, shorter remaining life, and potentially poorer performance, compared to their authentic counterparts. While solutions, such as on-chip age monitors, have been proposed for new designs, detecting the recycling of older legacy ICs already in use is much harder; no reliable solution currently exists. In this paper, we propose a new and highly effective approach for detecting recycled ICs by exploiting the powerup state of on-chip SRAMs to evaluate the age of the chip. Our methodology does not require the introduction of any special aging detection circuitry, nor the recording and saving of historical circuit performance data as a reference to detect degradation from use. Instead, we exploit the novel observation that in a new unused SRAM, an equal number of cells power up to the 0 and 1 logic states, and also that this distribution becomes skewed in time due to aging in operation. Since SRAMs exist in virtually all systems-on-chip (SoCs), this simple aging detection method is widely applicable to both old and new designs. It is also low cost since does not require any special test equipment. We present experimental results using commercial off-the-shelf SRAM chips to validate the effectiveness of the proposed approach.