A Spline-High Dimensional Model Representation for SRAM Yield Estimation in High Sigma and High Dimensional Scenarios

Abstract

Traditional Static Random-Access Memory (SRAM) yield estimation through Monte Carlo analysis is an extremely time-consuming process since it runs millions of expensive transistor-level simulations to get the yield results with the specified precision, especially for the large-scale circuits. In this paper, we develop an efficient yield analysis framework by integrating our novel performance metamodel into a state-of-art importance sampling method. The performance meta-model, named Spline-High Dimensional Model Representation (SP-HDMR), is used to substitute the expensive transistor-level simulations in yield estimation. The proposed SP-HDMR model provides a high computationally efficient formula expansion. It uses spline functions as the kernels to describe the various relations between the process parameters and SRAM read access delay. And an adaptive sampling method with sparsity analysis is developed to support SP-HDMR modeling. The experiments on the 40nm SRAM circuits validate the accuracy and the efficiency of the proposed yield analysis framework based on our SP-HDMR model with 1.3X $\sim 5\text{X}$ speedup over the other state-of-art methods within 9% relative error.

Keywords

• Yield analysis
• SRAM
• importance sampling
• SP-HDMR model