Patent ID: 7087293

Claim:
A method of forming a multilayer circuit comprising the steps: (a) providing an aluminum nitride substrate; (b) depositing on said substrate, a Pb-free and Cd-free glass composition comprising a dispersion of finely divided solids comprising: (i) a glass composition comprising, in mol %, 1–10% MO where M is selected from Ba, Sr, Ca and mixtures thereof, 5–30% MgO, 0.3–5% CuO, 0–2.5% P 2 O 5 , 0–2.5% ZrO 2 , 24–45% ZnO, 2–10% Al 2 O 3 , 35–50% SiO 2 and 0.1–3% A 2 O where A is one or more alkali elements, and (ii) an organic medium; (c) firing said composition and substrate forming an aluminum nitride article; (d) providing a metallic conductive composition; (e) depositing said conductive composition on said aluminum nitride article; and (f) firing said aluminum nitride article and said conductive composition.