Localized sealing of interconnect structures in small gaps

1. A microelectronic device, comprising:

a first substrate having a first surface;

first interconnects located on the first surface;

a second substrate having a second surface spaced apart from the first surface with a gap between the first surface and the second surface;

second interconnects located on the second surface;

lower surfaces of the first interconnects and upper surfaces of the second interconnects being coupled to one another for electrical conductivity between the first substrate and the second substrate;

a conductive collar around sidewalls of the first and second interconnects; and

a dielectric layer around the conductive collar.

2. The microelectronic device according to claim 1 , wherein:

the first and second interconnects respectively include metalization structure; and

the gap is approximately 5 microns or less.

3. The microelectronic device according to claim 1 , wherein:

the first and second interconnects respectively include metalization structures; and

the gap is equal to or less than a pitch between at least two adjacent conductive structures having the first interconnects and the second interconnects corresponding thereto coupled to one another for the electrical conductivity between the first substrate and the second substrate.

4. The microelectronic device according to claim 1 , wherein:

the first and second interconnects respectively include metalization structures; and

the gap is equal to or greater than a pitch between at least two adjacent conductive structures having the first interconnects and the second interconnects corresponding thereto coupled to one another for the electrical conductivity between the first substrate and the second substrate.

5. The microelectronic device according to claim 1 , wherein the dielectric layer adheres to the first surface, the second surface and the conductive collar for hermetic sealing of the conductive collar, the first interconnects and the second interconnects between the first surface and the second surface.

6. The microelectronic device according to claim 1 , further comprising:

a diffusion bonding layer between the first and second interconnects;

wherein the lower surfaces of the first interconnects and the upper surfaces of the second interconnects are coupled to one another for electrical conductivity by the diffusion bonding layer.

7. The microelectronic device according to claim 1 , further comprising:

an intermetallic compound layer between the first and second interconnects;

the lower surfaces of the first interconnects and the upper surfaces of the second interconnects being coupled to one another for electrical conductivity with the intermetallic compound layer.

8. The microelectronic device according to claim 1 , wherein the conductive collar includes an intermetallic compound.

9. The microelectronic device according to claim 7 , wherein the intermetallic compound of the conductive collar is around the sidewalls of the first and second interconnects.

10. The microelectronic device according to claim 1 , further comprising a diffusion barrier layer between the sidewalls of the first and second interconnects and the conductive collar.

11. The microelectronic device according to claim 1 , wherein the first substrate and the second substrate either respectively include a semiconductor die and an interposer or a first semiconductor die and a second semiconductor die.

12. A method for forming a microelectronic device, comprising:

applying a first layer of a first self-assembly matrix material with first conductive particles suspended therein onto first sidewalls and lower surfaces of first interconnects;

the first interconnects being on a first surface of a first substrate;

applying a second layer of a second self-assembly matrix material with second conductive particles suspended therein onto second sidewalls and upper surfaces of second interconnects;

the second interconnects being on a second surface of a second substrate;

removing a portion of the first layer for temporarily exposing the lower surfaces of the first interconnects;

removing a portion of the second layer for temporarily exposing the upper surfaces of the second interconnects; and

phase separating the first conductive particles from the first self-assembly matrix material and the second conductive particles from the second self-assembly matrix material for providing a conductive collar around sidewalls of the first and second interconnects and a dielectric layer around the conductive collar;

wherein the second surface is spaced apart from the first surface with approximately a 5 or less micron gap therebetween for the first and second interconnects diffusion bonded to one another.

13. The method according to claim 12 , further comprising diffusion bonding the lower surfaces of the first interconnects and the upper surfaces of the second interconnects one to another for electrical conductivity between the first substrate and the second substrate prior to the phase separating.

14. The method according to claim 13 , wherein the diffusion bonding of the lower surfaces of the first interconnects and the upper surfaces of the second interconnects one to another includes forming a diffusion bonding layer between the lower surfaces and the upper surfaces corresponding thereto.

15. The method according to claim 12 , wherein the phase separating comprises:

heating the first self-assembly matrix material and the second self-assembly matrix material to form the conductive collar with an intermetallic compound including the first conductive particles from the first self-assembly matrix material and the second conductive particles from the second self-assembly matrix material;

self-aligned adhering of the intermetallic compound to the sidewalls of the first and second interconnects; and

self-aligned segregating of the first self-assembly matrix material and the second self-assembly matrix material from the intermetallic compound as a polymer network to provide the dielectric layer around the conductive collar.

16. The method according to claim 12 , wherein the phase separating comprises separating the first conductive particles from the first self-assembly matrix material and the second conductive particles from the second self-assembly matrix material for providing a barrier layer around sidewalls of the first and second interconnects, the conductive collar around the barrier layer, and the dielectric layer around the conductive collar.

17. The method according to claim 16 , wherein the phase separating comprises:

heating the first self-assembly matrix material and the second self-assembly matrix material to form the barrier layer and the conductive collar;

self-aligned adhering of the barrier layer to the sidewalls of the first and second interconnects;

self-aligned adhering of the conductive collar to side surfaces of the barrier layer; and

self-aligned segregating of the first self-assembly matrix material and the second self-assembly matrix material from the conductive collar as a polymer network to provide the dielectric layer around the conductive collar.

18. The method according to claim 12 , wherein:

the removing of the portion of the first layer includes planarizing the lower surfaces for the temporary exposing thereof; and

the removing of the portion of the second layer includes planarizing the upper surfaces for the temporary exposing thereof.

19. A method for forming a microelectronic device, comprising:

applying a first layer of a first self-assembly matrix material with first conductive particles suspended therein onto first sidewalls and lower surfaces of first interconnects;

the first interconnects being on a first surface of a first substrate;

applying a second layer of a second self-assembly matrix material with second conductive particles suspended therein onto second sidewalls and upper surfaces of second interconnects;

the second interconnects being on a second surface of a second substrate;

putting the first layer on the lower surfaces and the second layer on the upper surfaces proximal to or in contact with one another;

phase separating the first conductive particles from the first self-assembly matrix material and the second conductive particles from the second self-assembly matrix material for providing a conductive collar around sidewalls of the first and second interconnects, a bonding layer between the lower surfaces of the first interconnects and the upper surfaces of the second interconnects, and a dielectric layer around the conductive collar;

wherein the second surface is spaced apart from the first surface with approximately a 5 or less micron gap therebetween for the first and second interconnects intermetallic bonded to one another.

20. The method according to claim 19 , wherein the phase separating comprises:

pressing a portion of the first layer associated with the lower surfaces of the first interconnects onto a portion of the second layer associated with the upper surfaces of second interconnects;

heating the first self-assembly matrix material and the second self-assembly matrix material to form:

the conductive collar with an intermetallic compound including a first portion of the first conductive particles from the first self-assembly matrix material and a first portion of the second conductive particles from the second self-assembly matrix material; and

the bonding layer with the intermetallic compound including a second portion of the first conductive particles from the first self-assembly matrix material and a second portion of the second conductive particles from the second self-assembly matrix material;

self-aligned adhering of the intermetallic compound to the sidewalls of the first and second interconnects; and

self-aligned segregating of the first self-assembly matrix material and the second self-assembly matrix material from the intermetallic compound as a polymer network to provide the dielectric layer around the conductive collar.