Fault Group Pattern Matching With Efficient Early Termination for High-Speed Redundancy Analysis

Abstract

Advances in memory density and capacity have had the consequence of increasing the probability of memory faults. For this reason, redundancy analysis (RA) and repair are used as effective solutions to improve memory yield. However, as the growth of the number of memory cells increases, it causes increase of the number of faulty cells and results in increase of difficulty of fault analysis. Although various RA methodologies have been proposed, most of them require a long analysis time or fast analysis speed without achieving a 100% normalized repair rate. Furthermore, research on conventional RA methodologies has not included effective early termination methods. Therefore, in this paper, fault group pattern matching (FGPM) is proposed for high speed RA with an effective early termination method. It can achieve very fast analysis with a 100% normalized repair rate. Additionally, it can finish the analysis rapidly by the proposed early termination method when a memory cannot be repaired. Experimental results demonstrate that the FGPM is highly effective in reducing analysis time with the achievement of a 100% normalized repair rate. In addition, the effectiveness of the proposed early termination is shown.