Flexible hybrid interconnect circuits
Provided are flexible hybrid interconnect circuits and methods of forming thereof. A flexible hybrid interconnect circuit comprises multiple conductive layers, stacked and spaced apart along the thickness of the circuit. Each conductive layer comprises one or more conductive elements, one of which is operable as a high frequency (HF) signal line. Other conductive elements, in the same and other conductive layers, form an electromagnetic shield around the HF signal line. Some conductive elements in the same circuit are used for electrical power transmission. All conductive elements are supported by one or more inner dielectric layers and enclosed by outer dielectric layers. The overall stack is thin and flexible and may be conformally attached to a non-planar surface. Each conductive layer may be formed by patterning the same metallic sheet. Multiple pattern sheets are laminated together with inner and outer dielectric layers to form a flexible hybrid interconnect circuit.
1. A flexible hybrid interconnect circuit, having a thickness, the flexible hybrid interconnect circuit comprising:
a first outer dielectric, comprising an opening;
an insulating plug, filling the opening of the first outer dielectric;
a second outer dielectric;
an inner dielectric;
a first conductive element;
a second conductive element, stacked with the first conductive element along the thickness of the flexible hybrid interconnect circuit and between the first outer dielectric and the second outer dielectric, wherein at least a portion of the inner dielectric extends between the first conductive element and the second conductive element and support the first conductive element and the second conductive element relative to each other;
a third conductive element, stacked together with the first conductive element and the second conductive element along the thickness of the flexible hybrid interconnect circuit and between the first outer dielectric and the second outer dielectric; and
an interconnecting via, protruding through the first conductive element, the second conductive element, and at least the portion of the inner dielectric,
wherein the interconnecting via forms an electrical connection between the first conductive element, the second conductive element, and the third conductive element.
2. The flexible hybrid interconnect circuit of claim 1 , wherein the interconnecting via is positioned between the first outer dielectric and the second outer dielectric such that the first outer dielectric and the second outer dielectric isolate the interconnecting via from the environment.
3. The flexible hybrid interconnect circuit of claim 1 , wherein the interconnecting via protrudes through the third conductive element.
4. The flexible hybrid interconnect circuit of claim 1 , wherein the inner dielectric comprises crosslinked low-density polyethylene (LDPE).
5. The flexible hybrid interconnect circuit of claim 1 , wherein the inner dielectric comprises a flame retardant.
6. The flexible hybrid interconnect circuit of claim 5 , wherein the inner dielectric comprises a polymer matrix with the flame retardant provided as particles dispersed in the polymer matrix.
7. The flexible hybrid interconnect circuit of claim 1 , wherein at least one of the first outer dielectric or the second outer dielectric comprises a flame retardant paper.
8. The flexible hybrid interconnect circuit of claim 1 , further comprising an interconnect hub and a third conductive element, wherein the interconnect hub is configured to selectively connect and disconnect the third conductive element and the interconnecting via.
9. The flexible hybrid interconnect circuit of claim 8 , wherein the interconnect hub is remotely controlled using one of the first conductive element, the second conductive element, or the third conductive element.
10. The flexible hybrid interconnect circuit of claim 8 , wherein the interconnect hub is one of a field-programmable gate array (FPGA), a controller, or a computer chip.
11. The flexible hybrid interconnect circuit of claim 1 , wherein at least one of the first conductive element and the second conductive element is selected from the group consisting of a shield, a signal line, and a power conductor.
12. The flexible hybrid interconnect circuit of claim 1 , wherein the interconnecting via extends between the first outer dielectric and the second outer dielectric and interfaces each of the first outer dielectric and the second outer dielectric.
13. The flexible hybrid interconnect circuit of claim 1 , wherein at least one of the first conductive element, the second conductive element, and the third conductive element is a rolled metal foil.
14. The flexible hybrid interconnect circuit of claim 1 , wherein each of the first conductive element, the second conductive element, and the third conductive element is a rolled metal foil.
15. The flexible hybrid interconnect circuit of claim 1 , wherein at least one of the first conductive element, the second conductive element, and the third conductive element comprises a base sublayer and a surface sublayer, having a different composition than the base sublayer.
16. The flexible hybrid interconnect circuit of claim 8 , wherein the interconnect hub comprises a hub mounting adhesive, comprising a polyethylene liner and an acrylic adhesive disposed on the polyethylene liner.
17. The flexible hybrid interconnect circuit of claim 8 , further comprising a hub cover plate, mounted to the interconnect hub using a plate mounting adhesive and providing mechanical support and strain relief to electrical connections between the interconnect hub and at least one of the first conductive element, the second conductive element, and the third conductive element.
18. The flexible hybrid interconnect circuit of claim 8 , wherein the interconnect hub is configured to form a direct electrical connection to a twisted pair cable.
19. The flexible hybrid interconnect circuit of claim 1 , wherein a thickness of the flexible hybrid interconnect circuit is less than 5 millimeters.
20. The flexible hybrid interconnect circuit of claim 1 , wherein an aspect ratio of the flexible hybrid interconnect circuit is more than three.