US 2002/0158337 A1 · Multilayer interconnect structure containing air gaps and method for making

Multilayer interconnect structure containing air gaps and method for making

AssigneeInternational Business Machines Corporation

InventorsKatherina E. Babich, Roy Arthur Carruthers, Timothy Joseph Dalton, Alfred Grill, Jeffrey Curtis Hedrick, Christopher Vincent Jahnes, Ebony Lynn Mays, Laurent Perraud, Sampath Purushothaman, Katherine Lynn Saenger

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Abstract

A novel air-gap-containing interconnect wiring structure is described incorporating a solid low-k dielectric in the via levels, and a composite solid plus air-gap dielectric in the wiring levels. Also provided is a method for forming such an interconnect structure. The method is readily scalable to interconnect structures containing multiple wiring levels, and is compatible with Dual Damascene Back End of the Line (BEOL) processing.

Claims25

Dependent claims

An interconnect structure comprising a first wiring level and an overlying via level, said overlying via level having conductive vias embedded therein, said overlying via level having one or more solid via level dielectrics, said first wiring level having conductive wiring patterns embedded in an air-gap containing composite dielectric, said air gaps of said composite dielectric bounded on side surfaces by sidewall spacers of a solid sidewall spacer material and bounded on top surfaces by an overlying bridge layer of said one or more solid via level dielectrics.

A method for forming an interconnect structure comprising a lower via level and an upper line level, comprising the steps of:

selecting a substrate,
forming a via level dielectric layer on said substrate, said via level dielectric including one or more dielectric materials,
forming a layer of sacrificial material on said via level dielectric layer,
patterning said sacrificial material to form slightly oversized wiring-shaped cavities for line level wiring structures, said step of patterning including the step of stopping at a first via level dielectric layer;
forming a thin conformal layer of a sidewall spacer dielectric in said wiring-shaped cavities previously formed in said step of patterning,
etching said thin conformal layer sidewall spacer dielectric to form sidewall spacers on said sacrificial material,
patterning said via level dielectric with via-shaped cavities for via structures,
forming a thin conformal layer of a conductive liner material to provide a diffusion barrier, adhesion layer, and/or seed layer,
overfilling said via-shaped and wiring-shaped cavities with a conductive material,
removing said overfill of conductive material by chemical mechanical polishing, leaving a planar structure,
forming one or more layers on said planar structure to form a bridge structure, the bottom-most layer of said bridge structure being dielectric, at least bottom-most portion of said bottom-most dielectric layer remaining in the bridge structure as part of the via level dielectric for the next via level, and
removing said sacrificial material.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application

10/117,797Filed 2 Apr 2002

Priority

8 Feb 2000

Published

31 Oct 2002

Term ends

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Classification9 codes

H10W 20/076
Of dielectric parts comprising thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers: in via holes or…
H10W 20/071
Manufacture or treatment: of dielectric parts thereof
H10W 20/072
Of dielectric parts thereof: of dielectric parts comprising air gaps
H10W 20/077
Of dielectric parts comprising thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers: on sidewalls or on…