Dielectric bond plies for circuits and multilayer circuits, and methods of manufacture thereof

An interconnect subassembly, comprising:

• a bond ply comprising:
• a first outer layer comprising a thermosetting composition and a filler composition;
• a second outer layer comprising a thermosetting composition and a filler composition that is of the same type as that of the first outer layer;
• and
• an intermediate layer disposed between the first and the second outer layers, and comprising a thermosetting composition and a filler composition that is of the same type as the first and second outer layers,
• wherein the thermosetting composition of the intermediate layer has a degree of cure that is greater than a degree of cure for each of the thermosetting compositions of the first and the second outer layers;
• and
• a conductive layer disposed on a side of one of the outer layers opposite the intermediate layer.

A multilayer circuit stackup for the formation of a multilayer circuit, comprising:

• a first circuit comprising a first dielectric layer and a first wiring layer disposed thereon;
• a second circuit comprising a second dielectric layer and a second wiring layer disposed thereon;
• and
• a bond ply disposed between the first circuit and the second circuit, wherein the bond ply comprises:
• a first outer layer comprising a thermosetting composition and a filler composition;
• a second outer layer comprising a thermosetting composition and a filler composition that is of the same type as that of the first outer layer;
• and
• an intermediate layer disposed between the first and the second outer layers, and comprising a thermosetting composition and a filler composition that is of the same type as the first and second outer layers,
• wherein an amount of the filler composition in the intermediate layer is different than an amount of filler in the first and second outer layers.

A method of making a bond ply, comprising:

• forming an intermediate layer comprising a thermosetting composition and a filler composition;
• curing the thermosetting composition of the intermediate layer to a first degree;
• coating a first outer layer comprising a thermosetting composition and a filler composition that is of the same type as the intermediate layer onto a surface of the intermediate layer;
• and
• coating a second outer layer comprising a thermosetting composition and a filler that is of the same type as the intermediate layer and the first outer layer onto a surface of the intermediate layer opposite the first layer.

A method of making a circuit subassembly, comprising:

• disposing a bond ply between a patterned conductive layer and another conductive layer, a release layer, or a polymeric dielectric substrate layer to form a subassembly, wherein the bond ply comprises
• a first outer layer comprising a thermosetting composition and a filler composition;
• a second outer layer comprising a thermosetting composition and a filler composition that is of the same type as that of the first outer layer;
• and
• an intermediate layer disposed between the first and the second outer layers, and comprising a thermosetting composition and a filler composition that is of the same type as the first and second outer layers,
• wherein the thermosetting composition of the intermediate layer has a degree of cure that is greater than a degree of cure for each of the thermosetting compositions of the first and the second outer layers;
• and
• laminating the subassembly.