摘要
In this paper, the simulation of wafer images for Alternating Aperture Phase Shift Masks (AAPSM) is addressed by comparing wafer printing image with simulation. This is the first accuracy study for Virtual Stepper®'s newly developed AAPSM simulation module. The test reticle used includes 70 nm gate structures with three types of programmed phase defects: edge, corner, and center defects on rectangular shifter patterns. Wafer exposures are performed using 193 nm imaging technology and inspection images generated on a KLA-Tencor's SLF27 system. These images are used by the Virtual Stepper System to provide simulated wafer images using the specified stepper parameters. The results are compared to the simulation results from the Aerial Image Measurement System (AIMS™) and SEM images of resist patterns.