High-fidelity curvilinear mask optical proximity correction using tangent angle-arc length curve.

The curvilinear mask has received significant attention in recent years due to its capacity to provide superior lithography image quality in advanced nodes. Within the framework of curvilinear mask optical proximity correction (OPC), the selection and manipulation of control points are two pivotal steps. However, the existing methods employed in curvilinear mask OPC are characterized by complex algorithms, and the fidelity of print images is often suboptimal. To address these challenges, this paper employs a tangent angle-arc length (TAAL) curve, a one-dimensional function, to represent the two-dimensional mask boundary. The TAAL curve simplifies the process of control point selection and facilitates the determination of movement directions, thereby mitigating computational complexity. In addition, based on the TAAL curve, the small selection with directional movement (SSDM) method is introduced. Simulation results demonstrate that the TAAL-based SSDM method significantly reduces pattern errors (PAE) compared to the uniform selection and random movement methods.