Abstract
As the technology node keeps shrinking down to sub-28 nm, mask topography (Mask3D) effect is one of the most influential factors to draw intensive research lately. To build a successful Mask3D compact model, the runtime efficiency, accuracy and the flexibility to handle various geometry patterns are the three most important criterion to fulfill. Different approaches have been tried to resolve the difficulties in the full-chip modeling, but so far none of the existing Mask3D modeling methods have succeeded in meeting all the three criterion at the same time. It is often seen that an existing Mask3D model to succeed in one or two criteria, but fails in the rest. In this paper, we propose our innovative full chip Mask3D modeling method to successfully handle the above criterion at the same time. To our best of knowledge, it is the first ever Mask3D modeling in literature that is be able to achieve this goal. In our modeling flow, we first analyze the Mask3D effect by using rigorous simulation as the reference and generate edge-based kernels to mimic the Mask3D effect near the feature boundaries. The flexibility of handling the kernel helps us enable the support for all-angle patterns and be extendable for edge coupling effect and off-axis illumination. Our experimental results show that with only less than 30% runtime overhead compared to the conventional Mask2D model, we are able to achieve less than 0.8 nm CD RMS on the flexible feature patterns. An ILT-based OPC and simulation result is provided to validate the capability of all-angle support of our proposed model.
