Monolithic exploding foil initiator
A monolithic exploding foil initiator (EFI) or slapper detonator and the method for making the monolithic EFI wherein the exploding bridge and the dielectric from which the flyer will be generated are integrated directly onto the header. In some embodiments, the barrel is directly integrated directly onto the header.
1. A monolithic exploding foil initiator, comprising:
a header comprising a first feedthrough pin and a second feedthrough pin that are electrically isolated from each other and that penetrate an insulator element of the header, the insulator element having a top surface;
an initiator metal structure comprising
a bridge layer affixed to the top surface of the insulator element, the bridge layer comprising a bridge metal layer and having a pattern comprising a first pad region, a second pad region, and a bridge connecting the first pad region and the second pad region, wherein the first pad region is in electrical contact with the first feedthrough pin and the second pad region is in electrical contact with the second feedthrough pin and further comprising
a first conductive pad atop the first pad region and a second conductive pad atop the second pad region; and
a dielectric layer covering at least the bridge of the initiator metal structure, the dielectric layer having a thickness suitable for ejection of a flyer upon passage of an actuating current through the bridge.
2. The monolithic exploding foil initiator of claim 1 , further comprising a barrel atop the dielectric layer, wherein a bore of the barrel is aligned over the bridge and configured to allow passage of the flyer.
3. The monolithic exploding foil initiator of claim 1 , wherein the bridge layer further comprises an adhesion layer between the bridge metal layer and the top surface of the insulator element.
4. The monolithic exploding foil initiator of claim 3 , wherein the adhesion layer comprises an element selected from the group consisting of Ti, Cr, Hf, Ta, W, Si, and Zr.
5. The monolithic exploding foil initiator of claim 1 , wherein the bridge layer further comprises a diffusion barrier layer between the bridge metal layer and the first and second conductive pads, and optionally an adhesion layer between the bridge metal layer and the diffusion barrier layer.
6. The monolithic exploding foil initiator of claim 5 wherein the diffusion barrier layer comprises a material selected from the group consisting of Pd, Pt, Ni, Pd/Ni, Fe, Co, titanium nitride, titanium oxide, hafnium nitride, hafnium oxide, tantalum nitride, tantalum oxide, zirconium nitride, and zirconium oxide.
7. The monolithic exploding foil initiator of claim 1 , wherein the bridge metal layer comprises a metal selected from the group consisting of Al, Cu, Au, Ag, Ni, Pt, Ni/Cr, and alloys thereof.
8. The monolithic exploding foil initiator of claim 1 , wherein the first and second conductive pads comprise a material selected from the group consisting of Au, W, and a conductive material with a density greater than a density of the bridge layer.
9. The monolithic exploding foil initiator of claim 8 , wherein an adhesion layer between the bridge layer and the first and second conductive pads comprises an element selected from the group consisting of W, Ta, Ti, Zr, Si, and Hf.
10. The monolithic exploding foil initiator of claim 1 , wherein the dielectric layer comprises a material selected from the group consisting of parylene, polyimide, epoxy, epoxy-acrylate resin, and solder resist.
11. The monolithic exploding foil initiator of claim 1 , wherein the dielectric layer is a substantially continuous layer covering at least the bridge of the initiator metal structure and an exposed portion of the top surface of the insulator element adjacent to the initiator metal structure.