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Beam Delivery System for Excimer Laser

IP.com Disclosure Number: IPCOM000100985D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Klauser, HE: AUTHOR

Abstract

Disclosed is a beam delivery system for an excimer laser that makes economical use of the available beam cross section when the laser energy needs to be directed towards multiple, isolated features.

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This is the abbreviated version, containing approximately 76% of the total text.

Beam Delivery System for Excimer Laser

       Disclosed is a beam delivery system for an excimer laser
that makes economical use of the available beam cross section when
the laser energy needs to be directed towards multiple, isolated
features.

      The high utilization of the available beam cross section is
accomplished by coupling the laser energy into a bundle of quartz
optical fibers (typically 1 mm in diameter) and individually
redirecting the fibers onto the multiple features (without wasting
energy on the spaces between the features).  See the figure.

      The coupling of energy into the fiber is done by interposing a
set of closely spaced focusing lenslets 1 into the raw laser beam,
each lenslet condensing the beam energy falling on its area onto the
core of an individual optical fiber 2.  It is important that the
laser energy does not strike the cladding or the jacket of the
optical fiber as they have lower threshold to radiation damage.  It
is also important that the focal point of the lenslet be placed
outside the surface of the fiber (so that the beam strikes the fiber
surface at a divergent angle 3).  Focal length of the lenslet has to
be matched to the numerical aperture of the fiber.

      At the exit end of the optical fiber, another lenslet
collimates the energy onto the plane of the target 4.  The focal
length of this lens again is matched to the numerical aperture of the
optical fiber.

      In order to selectively block an...