Chemoepitaxy etch trim using a self aligned hard mask for metal line to via
A method of forming metal lines that are aligned to underlying metal features that includes forming a neutral layer atop a hardmask layer that is overlying a dielectric layer. The neutral layer is composed of a neutral charged di-block polymer. Patterning the neutral layer, the hardmask layer and the dielectric layer to provide openings that are filled with a metal material to provide metal features. A self-assembled di-block copolymer material is deposited on a patterned surface of the neutral layer and the metal features. The self-assembled di-block copolymer material includes a first block composition with a first affinity for alignment to the metal features. The first block composition of the self-assembled di-block copolymer is converted to a metal that is self-aligned to the metal features.
1. A method of forming electrically conductive structures that are aligned to underlying metal features comprising:
forming a neutral layer overlying a dielectric layer;
patterning the neutral layer and the dielectric layer to provide openings that are filled with a metal material to provide first metal features;
depositing a self-assembled di-block copolymer material on a patterned surface of the neutral layer and the first metal features, the self-assembled di-block copolymer material includes a first block composition with a first affinity for alignment to the first metal features;
converting the first block composition of the self-assembled di-block copolymer to second metal features that are self-aligned to the first metal features.
2. The method of claim 1 , wherein the neutral layer comprises a neutral charged di-block polymer.
3. The method of claim 2 , wherein the neutral layer comprises a coating of a crosslinked epoxy-containing polymer prepared from monomers comprising glycidyl (meth)acrylate, 2, 3-epoxycyclohexyl (meth)acrylate, (2,3-epoxycyclohexyl)methyl (meth)acrylate, 5,6-epoxynorbornene (meth)acrylate, epoxydicyclopentadienyl (meth)acrylate, or combinations thereof.
4. The method of claim 1 further comprising a hard mask layer between the neutral layer and the dielectric layer.
5. The method of claim 1 , wherein the self-assembled di-block copolymer material assembles into a first and second set of lamellae, the first set of lamellae comprise the first block composition and the second set of lamellae comprise a second block composition of the self-assembled di-block copolymer material.
6. The method of claim 1 , wherein the second set of lamellae are present on a surface of the neutral layer.
7. The method of claim 1 , wherein the first metal features comprise at least one via, and said second metal feature comprises at least one metal line.
8. The method of claim 1 , wherein the self-assembled di-block copolymer material comprises polystyrene-block-polymethylmethacrylate (PS-b-PMMA), polystyrene-block-polyisoprene (PS-b-PI), polystyrene-block-polybutadiene (PS-b-PBD), polystyrene-block-polyvinylpyridine (PS-b-PVP), polystyrene-block-polyethyleneoxide (PS-b-PEO), polystyrene-block-polyethylene (PS-b-PE), polystyrene-b-polyorganosilicate (PS-b-POS), polystyrene-block-polyferrocenyldimethylsilane (PS-b-PFS), polyethyleneoxide-block-polyisoprene (PEO-b-PI), polyethyleneoxide-block-polybutadiene (PEO-b-PBD), polyethyleneoxide-block-polymethylmethacrylate (PEO-b-PMMA), polyethyleneoxide-block-polyethylethylene (PEO-b-PEE), polybutadiene-block-polyvinylpyridine (PBD-b-PVP), polyisoprene-block-polymethylmethacrylate (PI-b-PMMA) or combinations thereof.
9. The method of claim 1 , wherein said converting the first block composition of the self-assembled di-block copolymer to a second metal feature that is self-aligned to the first metal features comprises:
sequential infiltration synthesis (SIS) of a metal containing material into the first block composition of the self-assembled di-block copolymer;
removal of the polymer scaffold of the first block composition of the self-assembled di-block copolymer; and
reduction of the metal containing material into a metal that provides said second metal features.
10. The method of claim 9 , wherein said reduction of the metal containing material comprises reduction of a metal oxide with a hydrogen gas.
11. A method of forming electrically conductive structures that are aligned to underlying metal features comprising:
forming a neutral layer overlying a dielectric layer;
forming first metal features through the neutral layer and the dielectric layer;
depositing a self-assembled di-block copolymer material atop the neutral layer and the first metal features, wherein the self-assembled di-block copolymer material includes a first block composition with a first affinity for alignment to the first metal features;
removing the first block composition of the self-assembled di-block copolymer material that is aligned with the first metal features selectively to a remainder of the self-assembled di-block that is not aligned with the first metal features; and
forming a metal in opening provided by said removing the first block composition to provide second metal features that are self-aligned with the first metal features.
12. The method of claim 11 , wherein the neutral layer is comprised of a neutral charged di-block polymer.
13. The method of claim 11 further comprising a hard mask layer between the neutral layer and the dielectric layer.
14. The method of claim 11 , wherein the self-assembled di-block copolymer material assembles into a first and second set of lamellae, the first set of lamellae comprise the first block composition and the second set of lamellae comprise a second block composition of the self-assembled di-block copolymer material.
15. The method of claim 11 , wherein said removing the first block composition comprises an etch process.
16. The method of claim 11 , wherein said forming the metal in the opening provided by said removing the first block composition to provide the second metal features comprises chemical vapor deposition, physical vapor deposition or a combination thereof.