Alexander N. Drozdov et al.
Mentor Graphics

The development of efficient resist models for optical and process proximity correction (OPC) is a problem of particular importance in microlithography. A resist model is considered efficient if it is fast and accurate and properly accounts for the transfer of latent image patterns into resist shapes.

This paper describes the runtime-accuracy tradeoff of the Compact Model 1 (CM1) resist model. The model is represented as a linear combination of the aerial image, orthogonal basis functions, and other terms designed to mimic various effects, such as acid and base diffusion, slope, and maximum and minimum local intensity. Clearly, the greater the number of terms involved, the more flexible and accurate the model. On the other hand, adding too many terms to the model substantially increases the OPC runtime and may lead to overfitting.