Approximate Yield Estimation of Correlated Failure Events for Near-threshold SRAM

2019 International Conference on Intelligent Manufacturing and Intelligent Materials

Sun, Zhongmao^1 ; Huang, Shuaibo^1 ; Yan, Hao^1

National ASIC System Engineering Research Center, Southeast University, No.2 Sipailou, Jiangsu Province, Nanjing, China^1

关键词: Advanced manufacturing technologies;    Asymptotic probabilities;    Correlated failures;    Failure correlation;    Linear combinations;    Near thresholds;    Process Variation;    Yield estimation;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/565/1/012008/pdf
DOI  :  10.1088/1757-899X/565/1/012008

来源: IOP

【 摘 要 】

In advanced manufacturing technology, SRAM yield estimation with correlation is a significant challenge due to process variations and structures especially at low voltage. In this paper, Double Asymptotic Probability Approximation (DAPA) method with Subset Analytical Model (SAM) is proposed to effectively estimate the probability of correlated failure event. SAM models SRAM failure events based on simulation of subsets of the equivalent circuit. DAPA obtains the recursive function of partial failure rate. The key idea is to approximate the failure rate of the entire system based on a linear combination of partial failure rates by decoupling failure correlation. Under TSMC 28 nm process, (M=N=8) SRAM failure rate is estimated at 500 mV with an error of less than 5% by the proposed method. Besides 2.5 hours of modeling consumption, the calculation can be completed in 7 seconds, which greatly reduces SRAM failure estimation time, compared with Monte Carlo method.