Dual damascene interconnect structures having different materials for line and via conductors

• US 6,958,540 B2
• Filed: 06/23/2003
• Issued: 10/25/2005
• Est. Priority Date: 06/23/2003
• Status: Active Grant

• Current Assignee: Auriga Innovations, Inc. (Quarterhill Inc. (f/k/a Wi-LAN Inc.))
• Original Assignee: International Business Machines Corporation
• Inventors: Lane, Michael, Simon, Andrew, Cooney, Edward III, Motsiff, William Thomas, Gambino, Jeffrey, Stamper, Anthony
• Primary Examiner(s): Parekh, Nitin
• Application Number:
  US10/604,026
• Publication Number:
  US 20040262764A1
• Time in Patent Office: 855 Days
• Field of Search: 257/750, 257/758, 257/759, 257/760, 257/774
• US Class Current: 257/750
• CPC Class Codes: H01L 21/76807 for dual damascene structures
• CPC Class Codes: H01L 21/76808 involving intermediate temporary filling with material
• CPC Class Codes: H01L 21/76811 involving multiple stacked pre-patterned masks
• CPC Class Codes: H01L 21/76813 involving a partial via etch
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76846 Layer combinations
• CPC Class Codes: H01L 21/76865 Selective removal of parts of the layer H01L21/76844 takes precedence
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/53295 Stacked insulating layers
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

Interconnect structures are disclosed for forming dual damascene back-end-of-line (BEOL) structure using materials for the vias or studs which are different from those used for the line conductors, or using materials for the via liner which are different from those used for the trench liner, or having a via liner thickness different from that of the trench liner. Preferably, a thick refractory metal is used in the vias for improved mechanical strength while using only a thin refractory metal in the trenches to provide low resistance.

Claims

1. An interconnect structure formed on a substrate, the structure comprising:

a first layer of a first dielectric material having at least one first conductor embedded therein, the first conductor having a top surface coplanar with a top surface of the layer of dielectric material;

a second layer of a second dielectric material overlying the first layer of dielectric material and having at least one second conductor embedded therein, the second conductor comprising at least one first portion and at least one second portion, wherein the first portion is in electrical contact with the first conductor, the second portion is overlying and in electrical contact with the first portion, the second portion has a lateral extent greater than that of the first portion, and the second portion has a top surface coplanar with a top surface of the second layer of dielectric material;

a first conductive liner disposed on an underside and sidewalls of the first portion and the second portion of the second conductor; and

a second liner disposed on an underside and sidewalls of only the first portion of the second conductor.

2. The interconnect structure of claim 1, further comprising a hardmask layer overlying the second layer of dielectric material, and wherein the second portion of the second conductor has a top surface coplanar with a top surface of the hardmask layer.

3. The interconnect structure of claim 1, wherein the second dielectric material is the same as the first dielectric material.

4. The interconnect structure of claim 1, wherein the second dielectric material is different from the first dielectric material.

5. The interconnect structure of claim 1, wherein the second conductor comprises copper.

6. The interconnect structure of claim 1, wherein the second liner comprises a material selected from the group consisting of titanium nitride, tantalum, tantalum nitride and tungsten, and the first liner comprises a material selected from the group consisting of tantalum nitride and tantalum.