Method of forming metal interconnect structures and metal via structures using photolithographic and electroplating or electro-less plating procedures

• US 6,265,301 B1
• Filed: 05/12/1999
• Issued: 07/24/2001
• Est. Priority Date: 05/12/1999
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Lee, Jin-Yuan, Wang, Chen-Jong
• Primary Examiner(s): Chaudhuri, Olik
• Assistant Examiner(s): Peralta, Ginette
• Application Number:
  US09/310,258
• Time in Patent Office: 804 Days
• Field of Search: 438/618, 438/622, 438/626, 438/627, 438/628, 438/678, 438/687, 257/758, 257/759, 257/766, 257/792, 427/98, 427/305
• US Class Current: 438/618
• CPC Class Codes: H01L 21/288 from a liquid, e.g. electrolytic deposition
• CPC Class Codes: H01L 21/2885 using an external electrical current, i.e. electro-deposition
• CPC Class Codes: H01L 21/76885 By forming conductive members before deposition of protective insulating material, e.g. pillars, studs

Abstract

A process for forming metal interconnect structures, and metal via structures, using electroplating, or electroless plating procedures, has been developed. The process features the use of disposable conductive layers, used as seed layers for the plating procedures. After formation of the desired metal structures, on the portion of seed layer, exposed in an opening in the photoresist shape, the photoresist shape, and the underlying portion of the disposable conductive layer, are removed, resulting in the desired metal structures.

Claims

1. A method of fabricating metal interconnect structures, and metal via structures, on a semiconductor substrate, comprising the steps of:

providing a first metal via structure, in a first insulator layer, with the top surface of the first metal via structure, exposed;

depositing a blanket first disposable conductive layer on a planar top surface topography, comprised of the top surface of said first insulator layer, and comprised of the top surface of said first metal via structure;

forming a first defining shape, on said blanket first disposable conductive layer, with a first opening, in said first defining shape, exposing a first portion of said blanket first disposable conductive layer that directly overlays the top surface of said first metal via structure;

forming an electroplated copper interconnect structure, on the portion of said blanket first disposable conductive layer, exposed in said first opening, of said first defining shape;

removing said first defining shape;

removing the portion of said blanket first disposable conductive layer, not covered by said electroplated copper interconnect structure, from the top surface of said first insulator layer using said electroplated copper interconnect structure as an etch mask;

depositing a second insulator layer;

planarizing said second insulator layer, exposing the top surface of said metal interconnect structure;

depositing a blanket second disposable conductive layer, on a planarized top surface of said second insulator layer;

forming a second defining shape, on said blanket second disposable conductive layer, with a second opening, in said second defining shape, exposing the portion of said blanket second disposable conductive layer that directly overlays a portion of the top surface of said electroplated copper interconnect structure;

forming a second metal via structure, comprised of electroplated copper, on the portion of said blanket second disposable conductive layer, exposed in said second opening, in said second defining shape;

removing said second defining shape; and

removing the portion of said blanket second disposable conductive layer, not covered by said second metal via.

2. The method of claim 1, wherein said first disposable conductive layer, is comprised of titanium, titanium nitride, tantalum nitride, or copper on tantalum nitride, obtained via R.F. sputtering, at a thickness between about 500 to 1000 Angstroms.

3. The method of claim 1, wherein said defining shape is comprised of photoresist, a low dielectric constant organic, or inorganic materials, silicon oxide, or silicon nitride.

4. The method of claim 1, wherein said electroplated copper interconnect structure, is formed to a thickness between about 2000 to 10000 Angstroms, via an electroplating procedure, performed at a temperature between about 20 to 40°

C., at a current density between about 0.01 to 0.05 amps/cm², using a plating solution comprised of a CuSO₄ based solution.

5. The method of claim 1, wherein the portion, of said first disposable conductive layer, not covered by said electroplated copper interconnect structure, is removed via a selective RIE procedure, using Cl₂ as an etchant.

6. The method of claim 1, wherein said second insulator layer, is a silicon oxide layer, obtained via PECVD procedures, at a thickness between about 5000 to 15000 Angstroms.

7. The method of claim 1, wherein said second insulator layer is a polyimide layer, obtained via spin on coating, and curing procedures, at a thickness between about 5000 to 15000 Angstroms.

8. The method of claim 1, wherein said second disposable conductive layer, is comprised of titanium, titanium nitride, tantalum nitride, or copper on tantalum nitride, obtained via R.F. sputtering, at a thickness between about 500 to 1000 Angstroms.

9. The method of claim 1, wherein said second defining shape is comprised of photoresist, silicon oxide, silicon nitride, or a low dielectric constant, organic, or inorganic material.

10. The method of claim 1, wherein said second metal via structure is comprised of copper, formed via an electroplating procedure, to a thickness between about 5000 to 15000 Angstroms, performed at a temperature between about 20 to 40°

C., at a current density between about 0.01 to 0.05 amps/cm², in a CuSO₄, based, plating solution.

11. The method of claim 1, wherein the portion, of said second disposable conductive layer, not covered by said metal via structure, is removed via a selective RIE procedure, using Cl₂ as an etchant.

12. A method of forming nickel interconnect structures, and nickel via structures, on a semiconductor substrate, via electroplating, or electro-less plating procedures, and featuring the use of blanket disposable conductive layers, formed on underlying planarized surfaces, used to enhance the plating procedures, comprising the steps of:

providing a metal via structure, located in a via hole in a first insulator layer;

depositing a blanket first disposable conductive layer, on a planarized top surface of said first insulator layer, and on the top surface of said metal via structure;

forming a first photoresist shape, on said blanket first disposable conductive layer, with a first opening, in said first photoresist shape, exposing a first portion of said blanket first disposable conductive layer that directly overlays the top surface of said metal via structure;

performing a first electroplating procedure, or a first electro-less plating procedure, to form said nickel interconnect structure, on said first portion of said blanket first disposable conductive layer, exposed in said first opening, in said first photoresist shape;

removing said first photoresist shape, exposing a second portion of said blanket first disposable conductive layer, not covered by said nicked interconnect structure;

selectively removing said second portion of said blanket first disposable conductive layer, from the top surface of said first insulator layer, using said nickel interconnect structure as an etch mask;

depositing a second insulator layer;

performing a chemical mechanical polishing procedure to planarize the top surface of said second insulator layer, and to expose the top surface of said nickel interconnect structure;

depositing a blanket second disposable conductive layer;

forming a second photoresist shape, on said blanket second disposable conductive layer, with a second opening, in said second photoresist shape, exposing a first portion, of said blanket second disposable conductive layer that directly overlays a portion of said nickel interconnect structure;

performing a second electroplating procedure, or a second electro-less plating procedure, to form said nickel via structure, on said first portion of said blanket second disposable conductive layer, exposed in said second opening, in said second photoresist shape;

removing said second photoresist shape, exposing a second portion of said blanket second disposable conductive layer, not covered by said nickel via structure; and

removing said second portion, of said second disposable conductive layer, using said nickel via structure as an etch mask.

13. The method of claim 12, wherein said first disposable conductive layer is comprised of titanium, titanium nitride, tantalum nitride, or copper on tantalum nitride, obtained via R.F. sputtering, at a thickness between about 500 to 1000 Angstroms.

14. The method of claim 12, wherein said nickel interconnect structure is formed at a thickness between about 2000 to 10000 Angstroms, via said first electro-less plating procedure, performed at a temperature between about 60 to 70°

C., using a plating solution of NiCl₂ and (CH₃)₂NHBH₃.

15. The method of claim 12, wherein said second portion, of said first disposable conductive layer, is removed via a selective RIE procedure, using Cl₂ as an etchant.

16. The method of claim 12, wherein said second insulator layer is a silicon oxide layer, obtained via PECVD procedures, at a thickness between about 5000 to 15000 Angstroms.

17. The method of claim 12, wherein said second insulator layer is a polyimide layer, obtained via a spin on, and a curing procedure, at a thickness between about 5000 to 1500 Angstroms.

18. The method of claim 12, wherein said second disposable conductive layer is comprised of either titanium, titanium nitride, tantalum nitride, or copper on tantalum nitride, obtained via R.F. sputtering, at a thickness between about 500 to 1000 Angstroms.

19. The method of claim 12, wherein said nickel via structure is formed at a thickness between about 5000 to 15000 Angstroms, via said second electro-less plating procedure, performed at a temperature between about 60 to 70°

C, in a NiCl₂ and (CH₃)₂NHBH₃ plating solution.

20. The method of claim 12, wherein said second portion, of said second disposable conductive layer, is removed via a selective RIE procedure, using Cl₂ as an etchant.