Method for fabrication of interconnection circuitry with electrically conductive features passing through a support and comprising core portions formed using nanoparticle-containing inks
Interposer circuitry ( 130 ) is formed on a possibly sacrificial substrate ( 210 ) from a porous core ( 130 ′) covered by a conductive coating ( 130 ″) which increases electrical conductance. The core is printed from nanoparticle ink. Then a support ( 120 S) is formed, e.g. by molding, to mechanically stabilize the circuitry. A magnetic field can be used to stabilize the circuitry while the circuitry or the support are being formed. Other features are also provided.
1. A manufacturing method comprising:
(1) forming at least part of interconnection circuitry, said at least part of the interconnection circuitry comprising a core portion and an electrically conductive layer overlaying at least part of the core portion and substantially conforming to the core portion, wherein forming the at least part of the interconnection circuitry comprises:
depositing ink onto a substrate, the ink comprising conductive nanoparticles carried by a non-gaseous fluid carrier, the conductive nanoparticles joining together to form the core portion, the core portion comprising one or more elongated segments above the substrate; and
forming the electrically conductive layer over at least said part of the core portion to increase the electrical conductance of at least one conductive feature, the electrically conductive layer covering an entire longitudinal surface of each elongated segment;
(2) forming a support that fills, at least up to a level above each elongated segment, a region above the substrate around each elongated segment, the support not completely covering said at least part of the interconnection circuitry to allow at least each elongated segment to be electrically contacted from above the support;
wherein the interconnection circuitry comprises one or more electrically conductive features passing through the support to interconnect circuits from a first side of the support to a second side of the support.
2. The method of claim 1 further comprising, after forming the support, removing at least part of the substrate to enable at least one elongated segment to be electrically contacted from below the support.
3. The method of claim 1 wherein the electrically conductive layer has a lower porosity than the porosity of at least one elongated segment immediately before forming the electrically conductive layer.
4. The method of claim 3 wherein the porosity of the electrically conductive layer is lower than the porosity of said at least one elongated segment immediately before forming the electrically conductive layer by at least 50%.
5. The method of claim 1 further comprising, after forming the electrically conductive layer but before forming the support, forming a dielectric layer over the electrically conductive layer over each elongated segment.
6. The method of claim 5 wherein the support is not dielectric, and the dielectric layer electrically insulates each elongated segment from the support.
7. The method of claim 1 further comprising, after forming the support, forming dielectric and conductive layers on the support to form circuitry above the support, the circuitry above the support being part of the interconnection circuitry.
8. The method of claim 1 wherein:
the core portion comprises a plurality of spaced apart electrically conductive core features; and
at least part of the electrically conductive layer is formed by electroplating when the core features are electrically connected to a source of electric power through an electrically conductive region interconnecting the core features.
9. The method of claim 8 wherein the electrically conductive region comprises at least part of the substrate.
10. The method of claim 8 wherein the electrically conductive region comprises a layer formed over the core features.