Low-k interconnect structure comprised of a multilayer of spin-on porous dielectrics

• US 6,603,204 B2
• Filed: 02/28/2001
• Issued: 08/05/2003
• Est. Priority Date: 02/28/2001
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Purushothaman, Sampath, Nitta, Satyanarayana V., Gates, Stephen McConnell, Hedrick, Jeffrey Curtis, Tyberg, Cristy Sensenich
• Primary Examiner(s): Nguyen, Ha Tran
• Application Number:
  US09/795,431
• Publication Number:
  US 20020117760A1
• Time in Patent Office: 888 Days
• Field of Search: 257/700-705, 257/750-768, 438/622-629
• US Class Current: 257/760
• CPC Class Codes: H01L 21/76811 involving multiple stacked pre-patterned masks
• CPC Class Codes: H01L 21/76835 Combinations of two or more different dielectric layers having a low dielectric constant H01L21/76832 takes precedence
• CPC Class Codes: H01L 23/5222 Capacitive arrangements or effects of, or between wiring layers other capacitive arrangements H01L23/642
• CPC Class Codes: H01L 23/5329 Insulating materials
• 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

A low-k dielectric metal conductor interconnect structure having no micro-trenches present therein and a method of forming such a structure are provided. Specifically, the above structure is achieved by providing an interconnect structure which includes at least a multilayer of dielectric materials which are applied sequentially in a single spin apply tool and then cured in a single step and a plurality of patterned metal conductors within the multilayer of spun-on dielectrics. The control over the conductor resistance is obtained using a buried etch stop layer having a second atomic composition located between the line and via dielectric layers of porous low-k dielectrics having a first atomic composition. The inventive interconnect structure also includes a hard mask which assists in forming the interconnect structure of the dual damascene-type. The first and second composition are selected to obtain etch selectivity of at least 10 to 1 or higher, and are selected from specific groups of porous low-k organic or inorganic materials with specific atomic compositions and other discoverable quantities.

Claims

1. An interconnect structure comprising:

a substrate having a patterned multilayer of dielectrics located thereon, said patterned multilayer of dielectrics including first and second porous low-k dielectrics which are directly separated from each other by a buried etch stop layer, said first and second porous low-k dielectrics having a first composition, and said buried etch stop layer is selected from the group consisting of an inorganic dielectric, an inorganic/organic hybrid dielectric, and an organic dielectric with the proviso that when the buried etch stop layer is an inorganic material then the first and second porous low-k dielectrics are organic dielectrics, and when the buried etch stop layer is an organic material then the first and second porous low-k dielectrics are inorganic dielectrics, said first composition and said buried etch stop layer are selected to provide an etch selectivity of at least 10;

1 or greater;

a polish stop layer atop said patterned multilayer of dielectrics over said second porous low-k dielectric; and

a metal conductor comprising at least one line and at least one via located within said patterned multilayer of dielectrics, wherein said at least one line is located in said second porous low-k dielectric and said at least one via is located in said first porous low-k dielectric.

2. The interconnect structure of claim 1 wherein said first and second porous low-k-dielectrics are organic dielectrics, and the buried etch stop layer is an inorganic low-k dielectric material or an inorganic/organic hybrid material.

3. The interconnect structure of claim 2 wherein said first and second porous low-k organic dielectrics have a pore size of from about 1 to about 50 nm at a volume percent porosity of from about 5 to about 35%.

4. The interconnect structure of claim 2 wherein said inorganic low-k dielectric buried etch stop layer is porous.

5. The interconnect structure of claim 4 wherein said inorganic porous low-k dielectric etch stop layer has a pore size of from about 5 to about 500 Å

at a volume percent porosity of from about 5 to about 80%.

6. The interconnect structure of claim 4 wherein said porous inorganic low-k dielectric buried etch stop layer has a density of from about 2.52 gm/cm³ to about 0.53 gm/cm³.

7. The interconnect structure of claim 2 wherein said first and second porous low-k organic dielectrics comprises C, O and H.

8. The interconnect structure of claim 7 wherein said first and second porous low-k organic dielectrics are aromatic thermosetting polymeric resins.

9. The interconnect structure of claim 2 wherein said buried etch stop layer comprises Si, O and H, and optionally C.

10. The interconnect structure of claim 8 wherein said buried etch stop layer comprises HOSP, MSQ, TEOS, HSQ, MSQ-HSQ copolymers, organosilanes, or any other Si-containing material.

11. The interconnect structure of claim 1 wherein said first and second porous low-k dielectrics are low-k inorganic dielectrics, and said buried etch stop layer is an organic low-k dielectric.

12. The interconnect structure of claim 11 wherein said first and second porous low-k inorganic dielectrics have a pore size of from about 5 to about 500 Å

at a volume percent porosity of from about 5 to about 80%.

13. The interconnect structure of claim 11 wherein said organic low-k dielectric buried etch stop layer is porous.

14. The interconnect structure of claim 13 wherein said organic porous low-k dielectric etch stop layer has a pore size of from about 1 to about 50 nm at a volume percent porosity of from about 5 to about 35%.

15. The interconnect structure of claim 11 wherein said organic dielectric etch stop comprises C, O and H.

16. The interconnect structure of claim 15 wherein said organic dielectric etch stop layer is an aromatic thermosetting polymeric resin.

17. The interconnect structure of claim 11 wherein said first and second porous low-k inorganic dielectric layers comprise Si, O and H, and optionally C.

18. The interconnect structure of claim 17 wherein said first and second porous low-k inorganic dielectric layers comprise HOSP, MSQ, TEOS, HSQ, MSQ-HSQ copolymers, organosilanes or any other Si-containing material.

19. The interconnect structure of claim 1 wherein said first and second porous low-k dielectrics have a dielectric constant of from about 1.1 to about 3.5.

20. The interconnect structure of claim 19 wherein said dielectric constant is from about 1.4 to about 3.0.

21. The interconnect structure of claim 1 wherein said multilayer of dielectrics have an effective dielectric constant of about 3.5 or less.

22. The interconnect structure of claim 1 wherein said substrate is a dielectric, a wiring level, an adhesion promoter layer, a semiconductor wafer or combinations thereof.

23. The interconnect structure of claim 1 wherein said substrate is a semiconductor wafer having an adhesion promoter layer formed thereon.

24. The interconnect structure of claim 1 wherein said polish stop layer is composed of the same material as the buried etch stop layer.

25. The interconnect structure of claim 1 wherein said polish stop layer is a spun-on low-k inorganic or organic dielectric.

26. The interconnect structure of claim 1 wherein said metal conductor is composed of Al, Cu, W, Ag or alloys thereof.

27. The interconnect structure of claim 1 wherein said metal conductor is composed of Cu.

28. The interconnect structure of claim 1 further comprising a liner material formed within said patterned multilayer of dielectrics prior to deposition of said metal conductor.

29. The interconnect structure of claim 28 wherein said liner material is composed of TiN, TaN, Ti, Ta, W, WN, Cr, Nb or combinations thereof.