Porous alumina templates for electronic packages

1. An interposer, comprising:

a region having first and second oppositely facing surfaces and a plurality of pores each extending in a first direction from the first surface towards the second surface, and having alumina extending along a wall of the each pore;

a plurality of connection elements extending in the first direction and formed in some of the plurality of pores, each connection element comprising an electrically conductive material extending into a respective one of the pores;

a first conductive path provided at the first surface for connection with a first component external to the interposer; and

a second conductive path provided at the second surface for connection with a second component external to the interposer,

wherein the first and second conductive paths are electrically connected through the electrically conductive material of at least some of the connection elements, and

at least some of the pores are disposed adjacent one another such that regions of the alumina which extend along the walls of directly adjacent pores are merged together in a common electrically isolating region surrounding and electrically isolating each of a plurality of the electrically conductive connection elements from one another.

2. The interposer of claim 1 , wherein each pore has a diameter of less than 2 micrometers.

3. The interposer of claim 1 , wherein the first and second conductive paths are at least one of a plurality of contacts or a redistribution layer (RDL).

4. The interposer of claim 1 , wherein the first conductive path further comprises:

a plurality of first contacts adjacent to the first surface for connection with a first component external to the interposer; and

wherein the second conductive path further comprises:

a plurality of second contacts adjacent to the second surface for connection with a second component external to the interposer,

wherein at least some of the first contacts are electrically connected with at least some corresponding second contacts through the connection elements.

5. The interposer of claim 1 , wherein at least some of the first conductive path is aligned with the connection elements.

6. The interposer of claim 1 , wherein others of the plurality of pores that do not have the connection elements extending therein incorporate voids.

7. The interposer of claim 1 , wherein some of the connection elements occupy an area of the first surface that surrounds areas occupied by others of the connection elements, the some of the connection elements configured as a heat spreader of the interposer.

8. The interposer of claim 1 , wherein others of the plurality of pores that do not have the connection elements extending therein are at least partially filled with a dielectric material overlying the alumina.

9. The interposer of claim 1 , wherein others of the plurality of pores that do not have the connection elements extending therein are at least partially filled with an electrically conductive material.

10. The interposer of claim 1 , wherein an aluminum region surrounds the common electrically isolating region, and the aluminum region is configured to provide a heat spreader function.

11. The interposer of claim 1 , wherein the plurality of pores extend within a peripheral region of the interposer, the peripheral region surrounding an aperture configured to at least partially receive a microelectronic element therein.

12. A method of fabricating an interposer, comprising: forming a plurality of pores in a region consisting of aluminum, each pore extending in a first direction from a first surface of the region towards a second surface opposite the first surface, and having alumina extending along a wall of each pore, the forming performed such that portions of the region remain as a plurality of electrically conductive connection elements extending in the first direction, the connection elements consisting essentially of aluminum and being electrically isolated from one another by at least the alumina extending along the walls of the pores; forming a first conductive path at the first surface for connection with a first component external to the interposer; forming a second conductive path at the second surface for connection with a second component external to the interposer, wherein the first and second conductive paths are electrically connected through at least some of the connection elements; and partially filling at least some of the pores with a dielectric material.

13. The method of claim 12 , wherein the first and second conductive paths are at least one of a plurality of contacts or a redistribution layer (RDL).

14. The method of claim 12 , wherein each pore has a diameter of less than 2 micrometers.

15. The method of claim 12 , wherein forming the first conductive path further comprises:

forming a plurality of first contacts adjacent to the first surface for connection with a first component external to the interposer; and

wherein forming the second conductive path further comprises:

forming a plurality of second contacts adjacent to the second surface for connection with a second component external to the interposer,

wherein at least some of the first contacts are electrically connected with at least some corresponding second contacts through the connection elements.

16. A microelectronic assembly, comprising:

a substrate having substrate contacts at a major surface of the substrate; and

an interposer electrically coupled with the substrate contacts, the interposer including:

a region having first and second oppositely facing surfaces and a plurality of pores, each pore extending in a first direction from the first surface towards the second surface, wherein alumina extends along a wall of each pore;

a plurality of electrically conductive connection elements extending in the first direction, the connection elements consisting essentially of aluminum and having at least a portion disposed outside of the interior volume of any individual pore, the connection elements electrically isolated from one another by at least the alumina extending along the walls of the pores;

a first conductive path provided at the first surface for connection with a first component external to the interposer; and

a second conductive path provided at the second surface for connection with a second component external to the interposer,

wherein the first and second conductive paths are electrically connected through at least some of the connection elements, and

at least some of the pores are disposed adjacent one another such that regions of the alumina which extend along the walls of directly adjacent pores are merged together in a common electrically isolating region surrounding and electrically isolating each of a plurality of the electrically conductive connection elements from one another.

17. The microelectronic assembly of claim 16 , further comprising a microelectronic element electrically connected with at least some of the substrate contacts, wherein the plurality of pores extend within a peripheral region of the interposer, the peripheral region surrounding an aperture, the microelectronic element extending at least partially within the aperture.

18. The microelectronic assembly of claim 17 , further comprising a circuit panel having panel contacts at a major surface of the circuit panel, the substrate contacts being electrically connected with at least some of the panel contacts.