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Metal Pattern Replication On Metal/Polymer Structures by Laser-Induced Lift-off

IP.com Disclosure Number: IPCOM000099347D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 2 page(s) / 80K

Publishing Venue

IBM

Related People

Cuomo, JJ: AUTHOR [+3]

Abstract

Disclosed is a process for selectively coating the top surface of metal features in a planar metal/polymer structure with a thin, layer (e.g., Z100-600 Ao of a different material. The applied material might be conductive and needed as an adhesion promoter or barrier layer, and selectivity might be required to avoid shorting between the metal features. The process is simple, dry and can have as few as two steps.

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Metal Pattern Replication On Metal/Polymer Structures by Laser-Induced Lift-off

       Disclosed is a process for selectively coating the top
surface of metal features in a planar metal/polymer structure with a
thin, layer (e.g., Z100-600 Ao of a different material.  The applied
material might be conductive and needed as an adhesion promoter or
barrier layer, and selectivity might be required to avoid shorting
between the metal features.  The process is simple, dry and can have
as few as two steps.

      The mechanism for the process has been dubbed "laser-induced
explosion" in (1), and has been used (a) with unpatterned (i.e.,
spatially uniform) CO2 laser radiation to completely remove metal
films from unpatterned epoxy substrates (1), and (b) to selectively
remove metal films from polymer or glass backing from regions
illuminated by patterned XeC1 excimer laser light (2).  In both
cases, heat transfer from the irradiated metal film into the
underlying polymer (or glass) leads to a localized pressure burst
(from decomposition or outgassing) which removes the metal.  In the
presently disclosed invention, selective removal is achieved with
unpatterned illumination by using a pre-patterned polymer. PROCESS
DESCRIPTION:

      Fig. 1a shows an example of the starting structure to be
selectively coated with substrate material 10, polymer material 15
and metal material 20. Fig. 1b shows the structure after the thin
coating 25 has been applied.  Figs. 1c and 1d show two outcomes of
the "flood expose" step, in which the sample is uniformly illuminated
with the (unpatterned) output of a pulsed laser at the appropriate
wavelength and fluence.  This step may be performed in vacuum or air.
 If wings remain (30 in Fig. 1c), they may be removed with a
mechanical and/or chemical brush to give the structure in Fig. 1d.

      As a specific examp...