Browse Prior Art Database

Hermetic Ceramic Seal Process

IP.com Disclosure Number: IPCOM000122251D
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 3 page(s) / 77K

Publishing Venue

IBM

Related People

Koblinger, O: AUTHOR

Abstract

During the production of aluminum or glass-ceramic substrates, narrow cracks or capillaries form between the metal contacts (of, say, copper) and the ceramic in the cooling down step following high-temperature sintering of the laminates (Fig. 1). In the subsequent processes for thin-film wiring on the ceramic, fluid penetrates the interior of the substrate, which later on, by outgassing and the like, may lead to destruction of the thin-film wiring.

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Hermetic Ceramic Seal Process

      During the production of aluminum or glass-ceramic
substrates, narrow cracks or capillaries form between the metal
contacts (of, say, copper) and the ceramic in the cooling down step
following high-temperature sintering of the laminates (Fig. 1).  In
the subsequent processes for thin-film wiring on the ceramic, fluid
penetrates the interior of the substrate, which later on, by
outgassing and the like, may lead to destruction of the thin-film
wiring.

      It is the object of this article to provide a hermetic seal on
both sides of the substrate by sidewall technology.

      Initially, using a suitable method (such as RIE or
chemical/mechanical polishing), a step of adequate height is produced
on the sidewalls of the via clusters (Fig. 2A). Then, an inorganic
film of oxide, nitride and the like is deposited on the substrate and
back etched (Figs. 2B and 2C).  Conceivable for this purpose are also
metal organic compounds (MOCVD) by which the process is shortened in
its entirety, as, similar to LPCVD, metal is simultaneously deposited
on both sides of the substrate and the deposited metal may later on
be directly used for the capture pads. The remaining inorganic
sidewalls of the copper vias (Fig. 2C) serve to seal the capillaries
against the ingress of process fluid.

      The thickness of the deposited layer is chosen such that a
capillary of about 100 nm width is covered by a spacer of at least
twice that width.  In...