Browse Prior Art Database

Process for Embedding Thin-Film Metallurgy of Small Line Width in Green Multilayer Ceramic Carriers

IP.com Disclosure Number: IPCOM000100705D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 93K

Publishing Venue

IBM

Related People

Elsner, G: AUTHOR [+3]

Abstract

The described process permits transferring thin-film wirings of structural dimensions of Z 6 mm (conductor widths) from a carrier foil to coarse-grained surfaces of, say, green sheets of glass ceramic and conventional Al2O3 ceramic material, without using a release layer between the wiring and the foil.

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Process for Embedding Thin-Film Metallurgy of Small Line Width in Green Multilayer Ceramic Carriers

       The described process permits transferring thin-film
wirings of structural dimensions of Z 6 mm (conductor widths) from a
carrier foil to coarse-grained surfaces of, say, green sheets of
glass ceramic and conventional Al2O3 ceramic material, without using
a release layer between the wiring and the foil.

      Thin-film technology, which is used to produce conductors in
carriers yields line widths that are 20 times smaller than those
obtainable by thick-film technology. Difficulties occur however when
thin-film technology is applied to green ceramic material.  Tests
made to overcome those difficulties have been unsuccessful, since
photolitho graphy cannot be implemented on the rough surface of the
green ceramic material reacting with photoresist.  To eliminate the
described difficulties, U.S. Patent 4,753,694 proposes fabricating
the thin-film metallurgy on a polymer carrier foil, covered with a
release layer, by evaporation, photolithography and etch processes,
laminating the metallurgy on the green ceramic material by means of
the carrier foil, and removing the carrier foil by peeling the
release layer from the laminated metallurgy.  However, this method
has the disadvantage that owing to the temperature-sensitive release
layer only low-temperature deposition and structuring processes may
be employed.   Such processes allow minimum line widths of only 25 mm
at the required layer thickness of 5 mm.

      Therefore, a method is proposed which permits transferring
thin-film wirings of structural dimensions of 6 mm (conductor widths)
to coarse-grained surfaces, of, say, green sheets of glass ceramic
and conventional Al2O3 ceramic material (as is currently employed for
MLCs), without using a release layer between the carrier foil and the
thin-film wiring.  This transfer process permits laminating finest
wiring patterns to soft ceramic materials, without observing strict
requirements for grain size distribution, porosity and waviness of
the ceramic material.  This thin-film transfer process essentially
comprises the steps of
      1.   fab...