Method for creating a fully self-aligned via

1. A method to provide a via, comprising:

providing a substrate comprising a first insulating layer having a plurality of parallel recessed first conductive lines extending in a first direction, the recessed first conductive lines having a top surface recessed below a top surface of the first insulating layer;

forming first pillars on the recessed first conductive lines, the first pillars extending orthogonal to the top surface of the first insulating layer;

depositing a second insulating layer around the first pillars and on the top surface of the first insulating layer;

selectively removing at least one of the first pillars to form at least one opening in the second insulating layer, leaving at least one first pillar on the recessed first conductive lines;

depositing a second conductive material in the at least one opening to form a first via and second conductive lines, the first via connecting the recessed first conductive lines to the second conductive lines; removing the at least one first pillar left on the recessed first conductive lines to form at least one bridging opening in the second insulating layer;

forming at least one bridging pillar on the recessed first conductive lines through the at least one bridging opening, the at least one bridging pillar extending orthogonal to a top surface of the second insulating layer;

depositing a third insulating layer around the at least one bridging pillar and on a portion of the second insulating layer;

removing the at least one bridging pillar to form at least one bridging opening in the second insulating layer and third insulating layer; and

depositing a third conductive material in the at least one bridging opening to form a bridging via and third conductive lines, the bridging via connecting the recessed first conductive lines to the third conductive lines.

2. The method of claim 1 , wherein forming the first pillars comprises forming a first pillar metal film on the recessed first conductive lines and growing the first pillars from the first pillar metal film.

3. The method of claim 2 , wherein growing the first pillar metal film into first pillars comprises one or more of oxidation or nitridation of the first pillar metal film.

4. The method of claim 1 , further comprising forming a liner on the recessed first conductive lines prior to forming the first pillars.

5. The method of claim 4 , further comprising removing the liner from the recessed first conductive lines after forming the opening in the second insulating layer and before depositing the second conductive material.

6. The method of claim 1 , wherein depositing the second insulating layer comprises depositing a second insulating material on the first insulating layer, around the first pillars and on a top of the at least one first pillar to form an overburden of the second insulating layer; and planarizing the second insulating layer to remove the overburden of the second insulating layer and expose the top of the at least one first pillar.

7. The method of claim 1 , wherein selectively removing at least one of the first pillars comprises forming a hardmask on the second insulating layer, the hardmask having an opening over at least one first pillar; and removing the at least one first pillar to form the at least one opening.

8. The method of claim 1 , wherein forming the at least one bridging pillar comprises forming a bridging pillar metal film on the recessed first conductive lines through the at least one bridging opening and growing the at least one bridging pillar from the bridging pillar metal film.

9. The method of claim 1 , wherein the at least one first pillar and the at least one bridging pillar comprise tungsten oxide.

10. The method of claim 1 , wherein the recessed first conductive lines, the second conductive material, and the third conductive material independently comprise one or more of copper, ruthenium, nickel, cobalt, chromium, iron, manganese, titanium, aluminum, hafnium, tantalum, tungsten, vanadium, molybdenum, palladium, gold, silver, platinum, indium, tin, lead, antimony, bismuth, zinc, or cadmium.

11. The method of claim 10 , wherein the recessed first conductive lines comprise cobalt or copper and the second conductive material comprises the other of cobalt or copper.

12. The method of claim 1 , wherein the first insulating layer, the second insulating layer and the third insulating layer are independently selected from the group consisting of oxides, carbon doped oxides, porous silicon dioxide, carbides, oxycarbides, nitrides, oxynitrides, oxycarbonitrides, polymers, phosphosilicate glass, fluorosilicate (SiOF) glass, organosilicate glass (SiOCH), or any combinations thereof.

13. A method to provide a via, comprising:

providing a substrate comprising a first insulating layer having a plurality of parallel recessed first conductive lines extending in a first direction, the recessed first conductive lines having a top surface recessed below a top surface of the first insulating layer, the first insulating layer comprising ultra low-κ and the recessed first conductive lines comprising copper or cobalt;

forming a first pillar metal film comprising tungsten on the recessed first conductive lines and growing at least one first pillar comprising tungsten oxide from the first pillar metal film on the recessed first conductive lines, the at least one first pillar extending orthogonal to the top surface of the first insulating layer;

depositing a second insulating layer on the first insulating layer, around the first pillars and on a top of the at least one first pillar to form an overburden of the second insulating layer, the second insulating layer comprising a flowable silicon oxide;

planarizing the second insulating layer to remove the overburden of the second insulating layer and expose the top of the at least one first pillar;

forming a hardmask on the second insulating layer, the hardmask having an opening over at least one first pillar;

removing the at least one first pillar to form the at least one opening in the second insulating layer, leaving at least one first pillar on the recessed first conductive lines;

depositing a second conductive material in the at least one opening in the second insulating layer to form a first via and second conductive lines, the first via connecting the recessed first conductive lines to the second conductive lines; removing the at least one first pillar left on the recessed first conductive lines to form at least one bridging opening in the second insulating layer;

forming a bridging pillar metal film comprising tungsten on the recessed first conductive lines through the at least one bridging opening;

growing at least one bridging pillar comprising tungsten oxide from the bridging pillar metal film, the at least one bridging pillar extending orthogonal to a top surface of the second insulating layer;

depositing a third insulating layer around the at least one bridging pillar and on a portion of the second insulating layer, the third insulating layer selected from the group consisting of oxides, carbon doped oxides, porous silicon dioxide, carbides, oxycarbides, nitrides, oxynitrides, oxycarbonitrides, polymers, phosphosilicate glass, fluorosilicate (SiOF) glass, organosilicate glass (SiOCH), or any combinations thereof;

removing the at least one bridging pillar to form at least one bridging opening in the second insulating layer and third insulating layer; and

depositing a third conductive material comprising copper or cobaltin the at least one bridging opening to form a bridging g via and third conductive lines, the bridging via connecting the recessed first conductive lines to the third conductive lines.