Study on Improvement of Resolution in Photolithographic Patterns with Pupil Phase-shift Filtering

摘要

In order to improve photolithographic resolution and focal depth of a projection photolithographic imaging system with an enough large numerical aperture, the basic principle of pupil phase-shift filtering has been investigated in detail. The mathematical model of filtering, the simulation and the photolithographic experiments have been carried. The theoretical analysis and experimental results show that both the photolithographic resolution and focal depth have been obviously improved with pupil phase-shift filtering. At the same time, the photolithographic window has been increased. Compared with amplitude filtering, the utilization of light energy and the potential ability to improve image quality of the phase filtering technique is fully excavated. It is an effective wavefront engineering technique for improving both photolithographic resolution and focal depth.