Abstract: Fine positioning of a shaped or patterned charged particle beam without use of intrusive fiducial marks is achieved by providing a dithered shadow pattern, preferably in the form of a grid, within the shaped or patterned charged particle beam. Light output from fiducial marks preferably formed of a scintillating material is reduced when the dithered shadow pattern is incident on some or all of the fiducial marks. The timing of the incidence of the shadow pattern on fiducial marks indicates the position of the shaped or patterned charged particle beam such that correction of the beam position on the target can be corrected to a small fraction of system resolution. The dither pattern and repetition period is chosen to avoid interference with uniformity of beam illumination of the target. Feedback of position error thus provides phase locked position correction in real time and is suitable for mask making since the fiducial marks are not intrusive.

Abstract: Fine positioning of a shaped or patterned charged particle beam without use of intrusive fiducial marks is achieved by providing a dithered shadow pattern, preferably in the form of a grid, within the shaped or patterned charged particle beam. Light output from fiducial marks preferably formed of a scintillating material is reduced when the dithered shadow pattern is incident on some or all of the fiducial marks. The timing of the incidence of the shadow pattern on fiducial marks indicates the position of the shaped or patterned charged particle beam such that correction of the beam position on the target can be corrected to a small fraction of system resolution. The dither pattern and repetition period is chosen to avoid interference with uniformity of beam illumination of the target. Feedback of position error thus provides phase locked position correction in real time and is suitable for mask making since the fiducial marks are not intrusive.

Abstract: A wavelength-selective optical switch having a first input port for accepting a plurality of copropagating optical channels, each of the channels having a distinct wavelength band. The optical switch includes first and second output ports. A wavelength-selective optical filter is connected to receive the copropagating optical channels from the first input port to extract a selected one of the channels while allowing the remaining channels to copropagate to the first output port. An interferometric switch is connected to receive the selected extracted channel; the interferometric switch includes a controller for controlling propagation of the selected extracted channel to either the second output port, the optical filter, or both. The optical filter is connected to receive from the interferometric switch an optical channel to be combined with the remaining copropagating channels and all directed to the first output port.