US 8,569,888 B2 · Wiring structure and method of forming the structure

Abstract

Disclosed is a wiring structure and method of forming the structure with a conductive diffusion barrier layer having a thick upper portion and thin lower portion. The thicker upper portion is located at the junction between the wiring structure and the adjacent dielectric materials. The thicker upper portion: (1) minimizes metal ion diffusion and, thereby TDDB; (2) allows a wire width to dielectric space width ratio that is optimal for low TDDB to be achieved at the top of the wiring structure; and (3) provides a greater surface area for via landing. The thinner lower portion: (1) allows a different wire width to dielectric space width ratio to be maintained in the rest of the wiring structure in order to balance other competing factors; (2) allows a larger cross-section of wire to reduce current density and, thereby reduce EM; and (3) avoids an increase in wiring structure resistivity.

Claims23

Dependent claims

A wiring structure comprising:

a dielectric layer;
an opening in said dielectric layer, said opening having vertical sidewalls, a lower portion, and an upper portion aligned above and wider than said lower portion such that said upper portion has a horizontal surface perpendicular to said vertical sidewalls;
a diffusion barrier layer lining said opening, said diffusion barrier layer having a first thickness in said lower portion of said opening and a second thickness in said upper portion of said opening, said second thickness being greater than said first thickness, wherein said diffusion barrier layer completely filling a space between said horizontal surface and said insulating cap layer;
a metal layer on said diffusion barrier layer and filling said opening;
and
an insulating cap layer on said dielectric layer, said diffusion barrier layer and said metal layer.

3 more elements

A method of forming a wiring structure, said method comprising:

providing a substrate comprising a first dielectric layer and a second dielectric layer on said first dielectric layer, said second dielectric layer having a top surface;
forming an opening extending from said top surface through said second dielectric layer into said first dielectric layer, said opening having vertical sidewalls, a lower portion with a first width in said first dielectric layer, and an upper portion with a second width that is greater than said first width in said second dielectric layer, said upper portion being aligned above said lower portion such that said upper portion has a horizontal surface perpendicular to said vertical sidewalls, said horizontal surface comprising a portion of a top surface of said first dielectric layer;
lining said opening with a diffusion barrier layer such that said diffusion barrier layer has a first thickness in said lower portion of said opening within said first dielectric layer and a second thickness in said upper portion of said opening within said second dielectric layer, said second thickness being greater than said first thickness;
forming a metal layer on said diffusion barrier layer so as to fill said opening;
and
forming an insulating cap layer on said second dielectric layer, said diffusion barrier layer and said metal layer.

3 more elements

Dependencies are inferred from the claim text.

Wiring structure and method of forming the structure

Life of this patent

Wiring structure and method of forming the structure

Life of this patent

Abstract

Claims23