Method of bonding a conductor composition including a lithium compound to an aluminum nitride substrate

A method of adherently depositing a thick film conductor composition on an aluminum nitride substrate comprising:

• (a) providing an aluminum nitride substrate;
• (b) applying a thick film conductor composition to such aluminum nitride substrate which includes:
• (i) a sufficient amount of conductive metallic material to render such thick film conductor composition electrically conductive when bonded to such aluminum nitride substrate, (ii) a glass frit binder for such conductive metallic material capable of being bonded to such aluminum nitride substrate, such glass frit binder comprising from about 27.0 to about 56.5 percent silicon dioxide, from 0 to about 47.0 percent barium oxide, from about 4.5 to about 25.0 percent boron oxide, from 0 to about 18.0 percent lead oxide, from 0 to about 15.0 percent zinc oxide, from about 3.0 to about 14.0 percent aluminum oxide, from 0 to about 3.0 percent zirconium oxide, from 0 to about 9.0 percent magnesium oxide, from 0 to about 12.0 percent calcium oxide, from 0 to about 3.0 percent fluorine, from 0 to about 3.0 percent potassium oxide, from 0 to about 3.0 percent sodium oxide, from 0 to about 4.0 percent tungsten oxide, and from 0 to about 4.0 percent lithium oxide, wherein barium oxide plus lead oxide is present in an amount of at least about 15.0 percent, zinc oxide plus calcium oxide plus aluminum oxide is present in an amount of at least about 5.0 percent, calcium oxide plus magnesium oxide plus barium oxide is present in an amount of at least about 7.0 percent, calcium oxide plus magnesium oxide plus zirconium oxide is present in an amount of at least about 1.0 percent, zirconium oxide plus calcium oxide plus barium oxide is present in an amount of at least about 7.0 percent, and potassium oxide plus sodium oxide plus lead oxide or barium oxide is present in an amount of at least about 10.0 percent, (iii) a lithium containing adhesion compound capable of reacting with such aluminum nitride substrate upon heating so as to bond such thick film conductor composition to such aluminum nitride substrate, such lithium containing compound consisting of at least one compound selected from the group consisting of lithium carbonate, lithium hydroxide, =lithium fluoride, lithium metaborate, lithium nitride, lithium peroxide, lithium benzoate, lithium oxalate, lithium amide, lithium methoxide, lithium hydride, lithium oxide and lithium nitrate;
• and (iv) an organic dispersion medium for such thick film conductor composition;
• and
• (c) heating such so-applied thick film conductor composition to cause such lithium containing adhesion compound to react with such aluminum nitride substrate to promote adhesion between such thick film conductor composition and such aluminum nitride substrate.