Statistical SPICE analysis of a 0.18μm CMOS digital/analog technology during process development

This paper gives details of a methodology to extract statistical SPICE models on a developing deep sub micron CMOS technology. The approach uses a TCAD framework which integrates process, device, parameter extraction, and statistics software. The TCAD tools are calibrated by physical and electrical measurements on transistor test structures with different channel lengths. Once calibrated, a Monte Carlo experiment is run on all process control input parameters with realistic variations and the results then compared to in-line and E-test distributions. When satisfied that the variance in TCAD and measured distributions match, the framework can be used to extract BSIM3v3.2 parameters to generate statistical models. Multivariate statistics is used to determine the key process parameters which need to be controlled in-line to minimize device variation. This methodology is demonstrated using Chartered Semiconductor Manufacturing Ltd's 0.18μm CMOS core logic technology.