Embodiments of the present invention provide methods and apparatus for
removing debris particles using a stream of charged species. One
embodiment of the present invention provides an apparatus for removing
debris particles from a beam of radiation comprising a charged species
source configured to dispense electrically charged species, and a
collecting plate biased electrically opposite to the charged species from
the charged species source, wherein the collecting plate and the charged
species source are disposed on opposite sides of the beam of radiation, a
stream of charged species from the charged species source to the
collecting plate intersects the beam of radiation, the stream of charged
species is configured to attach and remove debris particles from the beam
of radiation by electrostatic force, and the collecting plate is
configured to receive the charged species and the debris particles
removed from the beam of radiation.