Spatial systematic mismatch assessment of pre-arranged layout topologies

A spatial systematic mismatch, occurring in the integrated circuit manufacturing process, leads to differences in parameters for two or more identical devices. It is widely accepted that placing devices into symmetrical patterns reduces the spatial systematic mismatch between their parameters. In this paper, a novel method based on linear and nonlinear parameter gradient modeling for the assessment of pre-arranged matched structures has been proposed. The direction of a parameter gradient against a layout topology on a wafer is unknown. The prearranged layout pattern is rotated against the modeled parameter gradient. In each step of the rotation, for example, with a 1-degree resolution, the mismatch between parameters is calculated. The peak mismatch value is then used for the comparison of the different pre-arranged patterns. The proposed method is independent of technology.