Optical Proximity Correction (OPC) is the most popular technique to handle design shape distortions arising from subwavelength lithography. Existing OPC models are typically very computationally expensive and thus not efficient to be incorporated for layout optimization. In this paper, we present an efficient, yet sufficiently accurate OPC cost model which can predict the optimal location of a wire segment for OPC optimization and give an upper bound of the interference amount, guaranteeing that the interference amount is never underestimated. Based on this cost model, we propose an OPC-aware wire perturbation algorithm for post-layout interconnect optimization. We show that the effects of wire perturbation have the concavity or monotonicity property which can dramatically reduce the search space for finding the optimal location of each wire for OPC optimization. Further, we can incrementally update the OPC cost of a wire by recomputing only the affected wires because of the property of superposition of our model. Experimental results show that our algorithm can efficiently obtain much better OPC results than a state-of-the-art OPC-friendly router, based on a leading commercial OPC tool.
[Show abstract][Hide abstract] ABSTRACT: As the technology of manufacturing process continues to advance, the process variation becomes more and more serious in nanometer designs. Optical proximity correction (OPC) is employed to correct the process variation of the diffraction effect. To obtain the desired layout as early as possible, routers must have some changes to handle the optical effects to speed up the OPC time and to avoid the routing result that cannot be corrected by the OPC process. In this paper, we propose two practical OPC-aware maze routing problems and present how to enhance an existing maze routing algorithm to get an optimal algorithm for each problem. The experimental results are also given to demonstrate the effectiveness of these two enhanced algorithms.
Design Automation Conference, 2005. Proceedings of the ASP-DAC 2005. Asia and South Pacific; 02/2005
[Show abstract][Hide abstract] ABSTRACT: Corner stitching is a technique for representing rectangular two-dimensional objects. It is especially well suited for interactive VLSI layout editing systems. The data structure has two important features: first, empty space is represented explicitly; and second, rectangular areas are stitched together at their corners like a patchwork quilt. This organization results in fast algorithms (linear or constant expected time) for searching, creation, deletion, stretching, and compaction. The algorithms are presented under a simplified model of VLSI circuits, and the storage requirements of the structure are discussed. Corner stitching has been implemented in a working layout editor. Initial measurements indicate that it requires about three times as much memory space as the simplest possible representation.
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems 02/1984; 3(1):87- 100. DOI:10.1109/TCAD.1984.1270061 · 1.00 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: om with shorter wavelenahs is still too costlv and unstable. As the technology migrates into the deep submicron manufacturing (DSM) era: the critical dimension of the circuits is getting smaller than the lithographic wavelength. The unavoidable light diffraction phenomena in the sub-wavelength technologies have become one of the major factors in the yield rate. Optical proximity correction (OPC) is one of the methods adopted to compensate for the light diffraction effect as a post layout process. However, the process is time-consuming and the results are still limited by the original layout quality. In this paper, we propose a maze routing method that considers the optical effect in the routing algorithm. By utilizing the symmetrical property of the optical system, the light diffraction is efficiently calculated and stored in tables. The costs that guide the router to minimize the optical interferences are obtained from these look-up tables. The problem is first formulated as a constrained maze routing .problem, then it is shown to be a multiple constrained shortest path problem. Based on the Lagrangian relaxation method, an effective algorithm is designed to solve the problem.
Proceedings of the 41th Design Automation Conference, DAC 2004, San Diego, CA, USA, June 7-11, 2004; 01/2004
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