Mask synthesis for 65nm SRAM manufacturing using gradient-based Inverse Lithography Technology (ILT)

Inverse Lithography Technology (ILT) is a promising solution to enhance the resolution of the optical system in deep-subwavelength lithography. In this paper, we introduce a gradient-based framework for mask synthesis. Firstly, we model the mask-to-wafer process using a continuous transfer function. Then Newton iterations are employed to solve the continuous inverse problems. Finally, we apply our framework to the mask synthesis for 65 nm SRAM manufacturing. The simulation results show that the optimized masks can be efficiently obtained and good fidelity in patterning is achieved.