Method for forming hermetic seals
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorBrian D. Gallagher
Life of this patent
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Abstract
A firmly adherent film 16 of bondable metal, such as silver, is applied to the surface 10 of glass or other substrate by decomposing a layer 14 of a solution of a thermally decomposable metallo-organic deposition (MOD) compound such as silver neodecanoate in xylene. The MOD compound thermally decomposes into metal and gaseous by-products. Sealing is accomplished by depositing a layer 18 of bonding metal, such as solder or a brazing alloy, on the metal film and then forming an assembly with another high melting point metal surface 20 such as a layer of Kovar. When the assembly is heated above the temperature of the solder, the solder flows, wets the adjacent surfaces and forms a hermetic seal between the metal film 14 and metal surface 20 when the assembly cools.
Claims12
A method of forming a seal between a first metal surface having a high melting point and a second surface selected from glass, ceramic, refractory or semi-conductor comprising the steps of:
- applying a solution of a silver-organic compound in an organic solvent to the second surface to form a thin, uniform layer, said compound including a moiety containing an atom selected from O, N or S bridging a silver atom to an organic group;
- evaporating the solvent from the solution to form a layer of said compound;
- thermally decomposing the compound to form a film of silver adherent to the second surface;
- depositing a layer of low melting point metal bonding material on the film;
- placing the first surface on the layer of material to form an assembly;
- and
- heating the assembly to above the melting point of the material and soldering or brazing the second surface to the first surface to form a seal.
Dependencies are inferred from the claim text.