Fast curvilinear optical proximity correction adopting quasi-uniform B-spline curves

Curvilinear mask has better lithography imaging fidelity than rectilinear mask. However, the mask data volume has limited its practical application. Curvilinear Optical Proximity Correction (OPC) outputs much smaller curvilinear mask file sizes than conventional Inverse Lithography Technology (ILT). The current Curvilinear OPC process is computationally intensive. This paper proposes a Curvilinear OPC method adopting quasi-uniform B-spline curves to improve the optimization efficiency. The ask Control Points (MCP) are set by equidistant contour sampling method. Then MCPs are connected by a closed quasi-uniform B-spline curve to characterize the curvilinear mask structure. Besides, the curvilinear mask structure is optimized by Particle Swarm Optimization (PSO) algorithm. Simulations and comparisons verify the superior optimization efficiency of the proposed methods.