Exposure latitude aware source and mask optimization for extreme ultraviolet lithography

Extreme ultraviolet (EUV) lithography is a new generation of integrated circuit manufacturing technology with great development prospects. EUV lithography has more significant demand for high exposure latitude (EL) due to greater requirements for the stability of the light source. Source and mask optimization (SMO) technology is widely used to compensate for imaging distortion. In this paper, we propose an EL-aware SMO (ELASMO) method that uses a low-resist threshold sensitivity (LRS) penalty function to improve the EL in EUV lithography. Compared to conventional SMO, the proposed ELASMO method can significantly enhance the aerial image contrast, improve the EL, and enlarge the process window while ensuring high imaging fidelity.