Method of connecting internal silver traces to external gold to produce a gold external side metal for an LTCC package
OwnerPhillip Fisher, James Elsner +1inventors
InventorsPhillip Fisher, James Elsner, Dean Marshall
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Abstract
A method of connecting internal silver traces to external gold to produce a gold external side metal for a low-temperature co-fired ceramic package includes the deposition of a ruthenium dioxide cermet barrier layer between layers of gold and silver. An LTCC package constructed in accord with the inventive method has gold, ruthenium and silver layers that are parallel to the LTCC package surface and normal to and also electrically coupled to a conductive trace formed within the LTCC layers of the package.
Claims26
A method of connecting internal silver traces to external gold to produce a gold external side metal for an LTCC package, comprising the steps of:
- providing a green tape;
- patterning a silver conductive material into conductive traces upon said green tape;
- laminating said patterned green tape;
- firing said laminated green tape;
- separating said LTCC package from said laminate and thereby exposing an end of at least one of said conductive traces;
- depositing silver upon said exposed end of at least one of said conductive traces;
- depositing ruthenium upon said silver deposit;
- and
- depositing gold upon said ruthenium deposit.
A selectively conductive substrate fabricated from at least one inorganic dielectric layer and at least one conductive trace patterned upon said at least one inorganic dielectric layer, wherein the improvement comprises a ruthenium conductive material electrically coupled to said at least one conductive trace, and a gold conductive material electrically coupled to said ruthenium conductive material and isolated from said at least one conductive trace by said ruthenium conductive material.
A method of connecting internal silver traces to external gold to produce a gold external side metal for an LTCC package, comprising the steps of:
- providing a tape composed of refractory materials and organic binders;
- selectively perforating said tape to form at least one hole therein;
- patterning a silver conductive material upon said tape;
- laminating said perforated and patterned tape;
- firing said laminated tape;
- separating said LTCC package from said laminated tape and thereby exposing said silver conductive material;
- screen printing an elemental silver cermet paste upon said exposed silver conductive material;
- firing said elemental silver cermet paste to produce a fired silver cermet contact layer;
- screen printing a ruthenium dioxide cermet paste upon said fired silver cermet contact layer;
- firing said ruthenium dioxide cermet paste to produce a fired ruthenium dioxide barrier layer;
- screen printing an elemental gold cermet paste upon said fired ruthenium dioxide barrier layer;
- and
- firing said elemental gold cermet paste.
A selectively conductive substrate fabricated from a multilayer refractory dielectric laminate and at least one conductive trace patterned within said multilayer refractory dielectric laminate and extending to an exterior thereof, wherein the improvement comprises a screen-printed and fired ruthenium cermet conductive layer electrically coupled and generally normal to said at least one conductive trace, and a screen-printed and fired gold cermet conductive layer electrically coupled to and deposited adjacent said ruthenium conductive layer and isolated from said at least one conductive trace by said ruthenium cermet conductive material.
Dependencies are inferred from the claim text.