An approach for relating model parameter variabilities to process fluctuations

A methodology that makes it possible to link circuit simulator model parameter variations and correlations to disturbances in the IC manufacturing process is presented. An example in which the variabilities among a set of 30 correlated empirical MOSFET model parameters from a 2- mu m CMOS process are represented by the variabilities of just six uncorrelated components with the aid of principal component analysis (PCA) and VARIMAX transformations is described. The derived uncorrelated components are interpreted in terms of the probable process input fluctuations causing them. These independent components may then be utilized to form the basis of realistic worst-case design methodologies or more rigorous statistical design techniques.<>