On the Reuse of Read and Write Assist Circuits to Improve Test Efficiency in Low-Power SRAMs

International audienceRead and write assist techniques are widely adopted to allow voltage scaling in low-power SRAMs. In particular, this paper analyzes two assist techniques: word line level reduction and negative bit line boost. The analyzed assist techniques improve read stability and write margin of core-cells when the SRAM operates at a lowered supply voltage. In this work, we investigate the impact of such assist techniques on the faulty behavior of low-power SRAMs. This analysis is based on extensive injection of resistive-open and resistive-bridging defects in core-cells of a commercial low-power SRAM. Our study determines the most stressful configuration of assist circuits to detect each faulty behavior induced by injected defects. We show that applying most stressful configurations of assist circuits during test phase can increase defect coverage up to 89% w.r.t. test solutions that do not exploit assist circuits. Based on this analysis, we present an efficient test solution that exploits the configuration of assist circuits as a parameter to maximize the detection of studied defects, while reducing time complexity up to 33% w.r.t state-of-the-art test algorithms

Test and Diagnosis of Integrated Circuits

The ever-increasing growth of the semiconductor market results in an increasing complexity of digital circuits. Smaller, faster, cheaper and low-power consumption are the main challenges in semiconductor industry. The reduction of transistor size and the latest packaging technology (i.e., System-On-a-Chip, System-In-Package, Trough Silicon Via 3D Integrated Circuits) allows the semiconductor industry to satisfy the latest challenges. Although producing such advanced circuits can benefit users, the manufacturing process is becoming finer and denser, making chips more prone to defects.The work presented in the HDR manuscript addresses the challenges of test and diagnosis of integrated circuits. It covers:- Power aware test;- Test of Low Power Devices;- Fault Diagnosis of digital circuits