Economic Aspects of Memory Built-in Self-Repair

The demand for built-in self-repair (BISR) methodologies that improve the yield of embedded memories is growing. A typical BISR scheme requires circuit modules that perform built-in self-test (BIST), built-in redundancy analysis (BIRA), real-time address remapping, and so on. The objective of BISR design is to maximize the final yield while keeping a reasonably low hardware overhead. In this work, the authors propose cost and benefit models, and evaluate the economic effectiveness of typical memory BISR implementations. They also present a simulator for that purpose based on the proposed cost models. The results are useful for evaluating the BISR schemes and implementations. Experimental results show that memory size impacts the cost-effectiveness of BISR more than production volume does.