Thick film conductor compositions for use with an aluminum nitride substrate

Claim 1

A thick film conductor composition adapted to be bonded to an aluminum nitride substrate comprising, in weight percent, a) from about 80 percent to about 99 percent of conductive metallic material to render said conductor composition electrically conductive when bonded to said substrate, said metallic material comprising a conductive metal selected from a group consisting of Au, Cu, Ag, and Pt; b) from about a trace amount to about 10 percent of a glass frit binder for said metallic material capable of being bonded to said substrate, said glass frit comprising from about 27.0 to about 56.5 percent silicon dioxide, from about 0 to about 47.0 percent barium oxide, from about 4.5 to about 25.0 percent boron oxide, from about 0 to about 18.0 percent lead oxide, from about 0 to about 15.0 percent zinc oxide, from about 3.0 to about 14.0 percent aluminum oxide, from about 0 to about 3.0 percent zirconium oxide, from about 0 to about 9.0 percent magnesium oxide, from about 0 to about 12.0 percent calcium oxide, from about 0 to about 3.0 percent fluorine, from about 0 to about 3.0 percent potassium oxide, from about 0 to about 3.0 percent sodium oxide, from about 0 to about 4.0 percent tungsten oxide, and from about 0 to about 4.0 percent lithium oxide, wherein barium oxide plus lead oxide is present in an amount at least equal to about 15.0 percent, zinc oxide plus calcium oxide plus aluminum oxide is present in an amount at least equal to about 5.0 percent, calcium oxide plus magnesium oxide plus barium oxide is present in an amount at least equal to 7.0 percent, calcium oxide plus magnesium oxide plus zirconium oxide is present in an amount at least equal to about 1.0 percent, zirconium oxide plus calcium oxide plus barium oxide is present in an amount at least equal to about 7.0 percent, and potassium oxide plus sodium oxide plus lead oxide or barium oxide is present in an amount at least equal to 10.0 percent; and c) from about a trace amount to about 4.0 percent of a lithium containing compound capable of reacting with said substrate upon heating so as to promote the adhesion of said conductor composition to said aluminum nitride substrate, said lithium containing compound including at least one compound selected from the group consisting of lithium carbonate, lithium hydroxide, lithium fluoride, lithium metaborate, lithium fluoride, lithium nitride, lithium peroxide, lithium benzoate, lithium oxalate, lithium amide, lithium methoxide, lithium hydride, lithium oxide and lithium nitrate.