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Method of Bonding Thin Film Nickel On Glass Ceramic in a Sintering Cycle That Has Forming Gas Followed by Steam

IP.com Disclosure Number: IPCOM000100131D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 3 page(s) / 85K

Publishing Venue

IBM

Related People

Acocella, J: AUTHOR [+4]

Abstract

The desired surface metallurgy for pin and chip join to glass-ceramic (GC) is nickel (Ni). BSM (Basic Storage Module) and TSM (Top Surface Metallurgy) bonding of pure Ni on GC is presently achieved, however, only with the controlled oxidation of Ni at 965@C, a process requiring the use of wet gas with very precise control of H2/H20 Ni. A conflict also exists between obtaining good bonds and retaining the proper ductility of Ni in the oxidative bonding cycle. To achieve good bonding, the Ni has to be slightly hardened, due to oxygen dissolution, and the residual carbon in the GC completely removed because of the sensitivity of the bonding cycle to it.

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Method of Bonding Thin Film Nickel On Glass Ceramic in a Sintering Cycle That Has Forming Gas Followed by Steam

       The desired surface metallurgy for pin and chip join to
glass-ceramic (GC) is nickel (Ni).  BSM (Basic Storage Module) and
TSM (Top Surface Metallurgy) bonding of pure Ni on GC is presently
achieved, however, only with the controlled oxidation of Ni at 965@C,
a process requiring the use of wet gas with very precise control of
H2/H20 Ni.  A conflict also exists between obtaining good bonds and
retaining the proper ductility of Ni in the oxidative bonding cycle.
To achieve good bonding, the Ni has to be slightly hardened, due to
oxygen dissolution, and the residual carbon in the GC completely
removed because of the sensitivity of the bonding cycle to it.

      The disclosed method of BSM and TSM bonding Ni using decal-thin
films in the presence of a reducing atmosphere overcomes these
disadvantages.  The decals are prepared in such a way that a thin
film of between 100 to 1000 angstroms of titanium (Ti) (1) is made to
exist between the Ni (2) and the green state GC (3) after transfer,
as seen in the following bonding sequence:

      The package is sintered in the normal manner, during

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 which the
residual carbon is removed by steam (730 - 750@C) (4), followed by a
forming gas (FG) or H2 sintering (5) at temperatures between 980 -
1000@C.

      The disclosed bonding procedure differs from other thin film
bonding methods in that complete oxidation of Ti to Ti02 (6) during
the steam segment occurs, followed by a controlled reduction of the
Ti02 to lower oxides.  The Ti layer is init...