SPATIAL-PHASE LOCKING OF ENERGY BEAMS FOR DETERMINING TWO-DIMENSIONAL LOCATION AND BEAM SHAPE

摘要

A method or system of spatial-phase locking a beam used in maskless lithography provides a fiducial grid with a single spatial-period, the fiducial grid being rotated at an angle with respect to a direction of scanning the beam; detects a signal generated in response to the beam being incident upon the fiducial grid; determines frequency components of the detected signal; and determines a two-dimensional location of the beam from phases of two determined fundamental frequency component. The method or system further determines a size of the beam from relative amplitudes of the determined fundamental and harmonic frequency components and/or determine a shape of the beam from relative amplitudes of the determined fundamental and harmonic frequency components. The method or system corrects a deflection of the beam in response to the determined two-dimensional location, and/or adjusts the size of the beam in response to the determined size, and/or adjusts the shape of the beam in response to the determined shape. If the method or system spatial-phase locks a plurality of beams used in maskless lithography, a fiducial grid with a varying spatial-period is utilized. In the plural beam method or system, the frequency components for each beam are determined using frequency-division multiplexing.