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Thin Dielectric and Metallization Layers Using Plasma Arc Spraying

IP.com Disclosure Number: IPCOM000121499D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 75K

Publishing Venue

IBM

Related People

Shaw, RR: AUTHOR [+3]

Abstract

Described is the use of a plasma arc spraying technique to apply dielectric glass ceramic layers directly to glass ceramic composition without the need for an intermediate coating. This results in a high rate of deposition, relative to ordinary techniques such as sputtering or evaporation.

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Thin Dielectric and Metallization Layers Using Plasma Arc Spraying

      Described is the use of a plasma arc spraying technique
to apply dielectric glass ceramic layers directly to glass ceramic
composition without the need for an intermediate coating.  This
results in a high rate of deposition, relative to ordinary techniques
such as sputtering or evaporation.

      Typically, thin dielectric layers, as used in thin film
redistribution (TFR) structures, are required to be very thin.  To
make the layers thin using sedimentation, casting or spraying
techniques require very small particle sizes. However, the practice
of sintering very small glass particles shows that the particles are
pulled apart by tensile stresses developed in the early stages of
sintering. This leads to extensive pinholing.  Pinholing can also be
caused by organic interference with the sintering process. Also, in
related technology, such as metallization of multilayer ceramic
(MLC), the interaction of metal conductor paste and glass ceramic
greensheets, in the pre-fired state, as well as the relative
shrinkage rates and onset temperatures during firing have been known
to cause problems.

      The concept described herein avoids the above problems found
with glass-ceramic slurries and metal pastes by using plasma arc
spraying deposition of powders.  The technique used is as follows:
      -    Deposition of glass-ceramic layers is readily accomplished
by spraying glass-ceramic powders. Particles are melted while passing
through the plasma torch and "splat-cooled" very rapidly during
deposition.  The resulting glassy structure is usually quite porous.
However, densification heat- treatment will sinter the layer to a
uniform, dense, high- quality microstructure which can be readily
crystallized w...