Effect of force control algorithms on the scanning probe microscope lithography system

This letter addresses the servo issue in the scanning probe microscope (SPM) lithography. The performance of the probe controller affects the ability of the lithography system to form uniform marks on the sample surface. Different control algorithms are tested on a commercial SPM system. The tests include the controller from the original system, a proportional integral differential controller, and a modern μ controller. The design procedure for the μ controller is described. The experimental results show that carefully tuned controllers are able to suppress the undesirable vibrations, and the μ controller achieves the most uniform lithography marks.