Dielectric surface modification in sub-40nm pitch interconnect patterning
AssigneeInternational Business Machines Corporation
InventorsNicholas Anthony Lanzillo, Chih-Chao Yang
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Abstract
Back end of line metallization structures and processes of fabricating the metallization structures generally include selectively modifying a top surface of an ultra-low k dielectric intermediate trench openings. The modified top surface of the ultra-low k dielectric includes an element such as nitrogen, carbon, silicon, or mixture thereof and has greater hydrophobicity than the ultra-low k dielectric underlying the top surface.
Claims20
A back end of line metallization structure comprising:
- a dielectric layer including two or more trench openings, the dielectric layer comprising an ultra-low dielectric having a k value of less than 2.2 and a top surface between trench openings modified with elements comprising nitrogen, carbon, silicon and mixtures thereof to form a modified top surface, wherein the modified top surface has greater hydrophobicity than the ultra-low k dielectric underlying the modified top surface.
A back end of the line process for forming a metallization structure layer, the process comprising:
- depositing a dielectric layer onto a surface, wherein the dielectric layer comprises an ultra-low k dielectric having a k value of less than 2.2;
- lithographically patterning and etching the dielectric layer to form trench openings;
- selectively modifying a top surface of the dielectric between the trench openings to form a modified top surface having greater hydrophobicity than the ultra-low k dielectric underlying the modified top surface;
- wet processing to clean and/or remove residues from prior fabrication steps;
- depositing a liner layer onto sidewalls and a bottom surface defined by trench openings;
- depositing a metal onto the liner layer and into the one or more openings;
- and
- planarizing a surface of the metal to remove an excess of the metal such that the uppermost surfaces of the metal and the dielectric layer are coplanar to each other.
A back end of the line process for modulating hydrophobicity at a top surface of an ultra-low k dielectric material located between trench openings in the ultra-low k dielectric material, the process comprising:
- selectively depositing an element comprising nitrogen, carbon, silicon, or mixtures thereof into the top surface of the ultra-low k dielectric material, wherein depositing the elements increases hydrophobicity at the top surface relative to the ultra-low k dielectric material underlying the top surface.
Dependencies are inferred from the claim text.