Pattern type specific modeling and correction methodology at high NA and off-axis illumination

摘要

In this work, a potential drawback of simultaneously representing a set of data that contains line-ends, isobar, block structure, and pitch linearity intensity signal using a single representative model have been resolved. In a typical model-OPC procedure, a set of pattern data representative of OPC layout is calibrated using a single representative model, and this model may be a scalar or a vector at constant threshold or variable threshold. Nevertheless, traditional methodology treats a set of pattern data as a whole believing that it provides a best representation of a more complicated environment. In this study, pattern type specific models are used to perform optical proximity correction. This multi-model approach distinguishes each pattern type and specified pitch range a priori to obtaining intensity signal by checking for neighboring segment. Based on this search result, its segment is classified into a pattern type and sub-group, and then, pattern specific models are applied. This approach provides improved calibration result for strong off-axis illumination and optical proximity correction result which will be difficult to achieve with a single representative model.