Disclosed are apparatus and methods for illuminating a sample, e.g.,
during an inspection of such sample for defects. In one aspect, the
illumination apparatus includes a bundle of fibers that each has a first
end and a second end. The illumination apparatus further includes an
illumination selector for selectively transmitting one or more incident
beams into one or more corresponding first ends of the optical fibers so
that the selected one or more incident beams are output from one or more
corresponding second ends of the fibers. The illumination apparatus also
includes a lens arrangement for receiving the selected one or more
incidents beams output from the corresponding one or more second ends of
the fibers and directing the selected one or more incident beams towards
the sample. The lens arrangement and the fibers are arranged with respect
to each other so as to image an imaging plane of the sample at the second
ends of the fibers. In one aspect, the incident beams are laser beams. In
a specific application of the invention, the sample is selected from a
group consisting of a semiconductor device, a semiconductor wafer, and a
semiconductor reticle.