Programmable thick film networks and method for making same

Claim 2

A programmable thick film network, characterized in that it comprises at least one thick film fusible device consisting of a substrate, a layer of dielectric glaze screened on said substrates, a thick film conductor in the form of a pattern of a fusible link having a narrow segment deposited on and straddling said glass substrate, and a second layer of glass deposited over said first layer of glaze and said narrow segment, said second layer confining said conductor pattern so that high energy released to said fusible link will cause said second layer of glass to rupture, releasing the conductive material and resulting in a high post fusing resistance.

Claim 3

A method for the manufacture of a thick film fusible device for use in a programmable thick film network as claimed in Claim 1 comprising the steps of: providing an electrically insulating substrate; applying thick film conductor termination pads either as an integral part of the fuse element or separate from the fuse element if a material other than the fuse element material is used for the terminations. screening a layer of dielectric glaze on said substrate; air drying said layer of dielectric glaze; firing said layer of dielectric glaze at 850 to 1000 0 C for five to ten minutes; applying a thick film conductor paste in the form of a pattern of a fusible link to said substrate and said glaze layer in such a manner that the narrow part of the conductor pattern straddless the glaze layer; air drying said conductor paste; applying a second layer of said dielectric glaze over said first layer of glaze and the narrow segment of said conductor pattern to confine the conductor pattern so that high energy released to the fuse element will cause said socond layer of glaze to rupture, releasing the conductor material and resulting in a high post fusing resistance; co-firing said second layer of glaze and said conductor material at 800 to 900°C.

Claim 4

The method of Claim 2 in which a second thick film conductor paste of a second conductive material is deposited in the form of termination pads on said substrate prior to the deposition of the first layer of dielectric glaze; and firing said termination pads.