Dual-layer alignment device and method

Abstract

A dual-layer alignment apparatus is disclosed which includes: a fixed frame () and, disposed thereon, a first measuring device () and a mark plate (), the mark plate () having a fixed-frame mark (); and a motion stage () and, disposed thereon, a reference mark (), a motion-stage mark () and a second measuring device (). The first measuring device () is configured to measure a relative positional relationship between the reference mark () and the motion-stage mark (), the second measuring device () is configured to measure a relative positional relationship between the reference mark () and the fixed-frame mark (), from which a final relative positional relationship between the motion-stage mark () and the fixed-frame mark () is derived, based on which the motion stage () is displaced to a target location. A corresponding dual-layer alignment method is also disclosed. In the apparatus, the motion stage () is the only movable component. Additionally, coordinate relationships can be calibrated in a static manner in order to immunize calibration accuracy from positioning accuracy of the motion stage (), such that the alignment accuracy is improved. Further, a dual- or multi-lens design can be employed to allow additional improvements in flexibility and alignment efficiency.