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A Thin Film High Damage Threshold Metal Laser Mask

IP.com Disclosure Number: IPCOM000120940D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 59K

Publishing Venue

IBM

Related People

Lankard, JR: AUTHOR [+2]

Abstract

Disclosed is a metal contact mask which will reflect greater than 90% of the unused laser light, thus allowing finer features to be patterned, thinner metal films to be used, reduces process costs, and improves thin film laser processing results. (Image Omitted)

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A Thin Film High Damage Threshold Metal Laser Mask

      Disclosed is a metal contact mask which will reflect greater
than 90% of the unused laser light, thus allowing finer features to
be patterned, thinner metal films to be used, reduces process costs,
and improves thin film laser processing results.

                            (Image Omitted)

      Polymers can be patterned by depositing a metal film directly
on the surface, patterning it with conventional photo- lithographic
techniques to create a mask image, and then scanning the mask surface
with a laser beam.  Where there is an opening in the metal film the
laser will ablate the polymer.  Copper is often used because it is an
excellent conductor of electricity and can be left on the surface and
used as a ground layer, but copper is a poor reflector at 308 nm; the
wavelength needed to ablate the polymer.  The laser light that is
absorbed by the copper during the laser ablation is instantly
converted to heat which can raise the temperature of the film,
possibly causing metal/polymer delamination, or enlargement of the
mask feature size by ablation of metal at the edges.  Metal films can
be made thicker to act as a better heat sink, but then patterning
small features in the metal becomes more difficult and the metal
deposition becomes more expensive.

      All of the above stated problems can be eliminated by
depositing a few hundred Angstroms of aluminum on top of the copper...