Controlled adhesion conductor
AssigneeDelco Electronics Corporation
InventorsDwadasi H. R. Sarma, Ponnusamy Palanisamy, John A. Hearn, Dwight L. Schwarz
Life of this patent
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Abstract
Compositions useful for printing controllable adhesion conductive patterns on a printed circuit board include finely divided copper powder, a screening agent and a binder. The binder is designed to provide controllable adhesion of the copper layer formed after sintering to the substrate so that the layer can lift off the substrate in response to thermal stress. Additionally, the binder serves to promote good cohesion between the copper particles to provide good mechanical strength to the copper layer so that it can tolerate lift off without fracture.
Claims7
A composition which is useful to form a controllably adherent conductor on a printed circuit board comprising by weight:
- at least about 75 percent by weight of a metal powder;
- about 7.5 to about 20 percent by weight of a screening agent comprising an organic vehicle including a solvent and a resin serving as a temporary binder;
- and
- about 0.05-5.0 percent by weight by a permanent binder comprising by weight between 50-70 percent bismuth oxide and the remainder is a frit that includes by weight between 50-65 percent PbO, 5-15 percent PbF.sub.2, 20-30 percent SiO.sub.2, 0-5 percent Al.sub.2 O.sub.3 and 5-15 percent B.sub.2 O.sub.3.
A composition for deposition as a layer on a ceramic substrate and for formation after drying and firing of a controllably adherent conductor on the substrate comprising by weight:
- at least about 75 percent of a metal powder;
- at least about 10 percent of an organic vehicle including a solvent and a resin as a smaller fraction;
- about 0.05-5 percent of a permanent binder comprising by weight between 50-70 percent bismuth oxide and the remainder is a frit that includes by weight between 50-65 percent PbO, 5-15 percent PbF.sub.2, 20-30 percent SiO.sub.2, 0-5 percent Al.sub.2 O.sub.3 and 5-15 percent B.sub.2 O.sub.3.
Dependencies are inferred from the claim text.