The pattern-matching based OPC approach for preemptively fixing the weak points

Abstract

The optical proximity correction (OPC) systematically adds the bias with respect to the designs to the mask, correcting the proximity effects associated with sub-wavelength features. Due to the complex nature of main features of the circuits, even a carefully tuned OPC recipe can yield thousands of weak points for each tape-out. Some of these weak points require manual fixings which might demand considerable amount of effects from engineers. It has been found that for different tape-outs, the resulting OPC patterns that require manual fixings share quite a lot commonalities or are even the same. Repeatedly performing manual fixings for the same type of weak points for different tape-outs presents a waste of human efforts. We therefore constructed a pattern matching library for these types of weak points. At the very of beginning of an OPC recipe, the design patterns of these types of weak points are used to scan the whole chip and find the same patterns. Then, the pre-calculated OPC and SB (scattering bar) layers are pasted to the relevant positions. The pasted patterns will be kept fixed and serve as boundary condition for the subsequent model-based OPC. The final resulting OPC layer will be free of those types of weak points that require manual fixings.