| Popis: |
The implementation of a simple, semi-empirical resist model into an OPC algorithm, which up to now uses aerial image simulation, is described. The model assumes that the main component of proximity effects comes from the aerial image. It uses two pattern density functions to describe the shift in edge placement due to resist and etching processes. Besides the parameters for the aerial image (numerical aperture, coherence, wavelength, lens aberrations, defocus, etc.), the model needs only four additional parameters. The model is tested using resist simulation and electrical linewidth measurement data from fully processed testwafers. For linewidths of 350 nm and larger, printed with i-line lithography into a standard i-line resist, the OPC algorithm with the implemented model reduces proximity effects to less than 10 nm. A similar performance is indicated by preliminary data of electrical linewidth measurements. |
