Integrating a bottomless via to promote adsorption of antisuppressor on exposed copper surface and enhance electroplating superfill on noble metals

• US 20080000678A1
• Filed: 06/30/2006
• Published: 01/03/2008
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Cheng, Chin-Chang, Johnston, Steven W.
• Granted Patent: US 7,694,413 B2
• Time in Patent Office: Days
• US Class Current: 174/262
• CPC Class Codes: C23C 18/1608 from pretreatment step, i.e. selective pre-treatment
• CPC Class Codes: C23C 18/165 Multilayered product layered product B32B
• CPC Class Codes: C23C 18/32 Coating with nickel, cobalt or mixtures thereof with phosphorus or boron C23C18/50 takes precedence
• CPC Class Codes: C25D 3/38 of copper
• CPC Class Codes: C25D 5/022 using masking means
• CPC Class Codes: C25D 7/123 Semiconductors first coated with a seed layer or a conductive layer
• CPC Class Codes: H01L 21/2885 using an external electrical current, i.e. electro-deposition
• CPC Class Codes: H01L 21/76844 Bottomless liners
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

A method for forming a copper interconnect is described. An opening in a dielectric layer disposed on a substrate is formed. A barrier layer is formed on the opening. A seed layer is formed on the barrier layer. The seed layer includes a noble metal copper alloy, the copper having less than 50% of the atomic weight of the noble metal copper alloy.

Claims

1. A method comprising:

forming an opening in a dielectric layer disposed on a substrate;

forming a barrier layer on the opening; and

forming a seed layer on the barrier layer, the seed layer having a noble metal-copper alloy, the copper having less than 50% weight of the noble metal-copper alloy.

2. The method of claim 1 wherein the seed layer further includes a reliability enhancing metal alloy species where the copper and the reliability enhancing metal alloy species having less than 50% weight of the noble metal-copper reliability enhancing metal alloy.

3. The method of claim 1, further comprising:

filling the opening with copper or a copper alloy layer using electroplating or electroless plating.

4. The method of claim 1, wherein forming the seed layer further comprises:

sputter depositing a layer of noble metal-copper alloy or noble metal-copper-reliability enhancing metal alloy from an alloyed sputter target or cosputtering on the upper surface of the barrier layer.

5. The method of claim 1, wherein forming the seed layer further comprises:

simultaneously introducing a noble metal and Copper precursors during CVD.

6. The method of claim 1, wherein forming the seed layer further comprises:

simultaneously introducing a noble metal, Copper, and a reliability enhancing metal precursor during CVD.

7. The method of claim 1, wherein forming the seed layer further comprises:

pulsing a Copper precursor and a noble metal precursor into a reactor during a pulsed CVD process.

8. The method of claim 1, wherein forming the seed layer further comprises:

pulsing a Copper precursor, a noble metal precursor, and a reliability enhancing metal precursor during a pulsed CVD process with or without a plasma treatment during deposition or as a post-treatment.

9. The method of claim 1, wherein forming the seed layer further comprises:

pulsing a Copper precursor and a noble gas precursor into a reactor during ALD with each pulse followed by a purge gas pulse or reducing gas pulse with or without a plasma treatment during or after one or more pulse steps.

11. The method of claim 1, wherein forming the seed layer further comprises:

pulsing a Copper precursor, a noble gas precursor, and a reliability enhancing metal precursor into a reactor during ALD with each pulse followed by a purge gas pulse or reducing gas pulse with or without a plasma treatment during or after one or more pulse steps.

13. The method of claim 1, wherein the noble metal substantially comprises a material selected from the group consisting of silver, palladium, platinum, rhodium, ruthenium, gold, iridium and osmium and combinations thereof.

14. The method of claim 1, wherein the barrier layer substantially comprises a material selected from the group consisting of tantalum, tungsten, titanium, ruthenium, tantalum nitride, tungsten nitride, titanium nitride, ruthenium nitride, tantalum silicide, tungsten silicide, titanium silicide, ruthenium silicide, tantalum carbide, tungsten carbide, titanium carbide, ruthenium carbide, and combinations thereof.

10. (canceled)

12. (canceled)

15. A method comprising:

forming an opening in a dielectric layer disposed on a copper interconnect of a substrate;

forming a barrier layer on the opening;

forming a seed layer on the barrier layer, the seed layer comprising a noble metal; and

etching the barrier layer and the seed layer at the bottom of the opening to expose the underlying copper interconnect.

16. The method of claim 15, wherein etching further comprises:

exposing a metallic copper capping material to act as a nucleation site for copper plating bath additives.

17. The method of claim 15, further comprising:

electroplating or electroless plating a copper or a copper alloy on the seed layer; and

filling the opening, the exposed copper from the copper interconnect functioning as a seed layer and enhancing the initial plating rate at the bottom of the opening.

18. The method of claim 17, wherein an electroplating or electroless plating bath further comprises one or more of an antisuppressor additive, a suppressor additive, or a leveler additive.

19. The method of claim 15, wherein the noble metal substantially comprises a material selected from the group consisting of silver, palladium, platinum, rhodium, ruthenium, gold, iridium and osmium and combinations thereof.

20. The method of claim 15, wherein the barrier layer substantially comprises a material selected from the group consisting of tantalum, tungsten, titanium, ruthenium, tantalum nitride, tungsten nitride, titanium nitride, ruthenium nitride, tantalum silicide, tungsten silicide, titanium silicide, ruthenium silicide, tantalum carbide, tungsten carbide, titanium carbide, ruthenium carbide, and combinations thereof.

25. The method of claim 15 further comprising:

immersing the copper interconnect of the substrate in a plating cell to fill the opening.

26. The method of claim 25 wherein the plating cell further comprises an anti-suppressor additive (ASUPP) without a suppressor or leveler.

21. An apparatus comprising:

a dielectric layer having an opening;

a barrier layer on the opening; and

a seed layer on the barrier layer, the seed layer having a noble metal-copper alloy, the copper having less than 50% weight of the noble metal-copper alloy layer.

22. The apparatus of claim 21 wherein the seed layer further includes a reliability enhancing metal alloy species where the copper and the reliability enhancing metal alloy species having less than 50% weight of the noble metal-copper reliability enhancing metal alloy.

23. An apparatus comprising:

a dielectric layer having an opening, the dielectric layer disposed on a copper interconnect of a substrate;

a barrier layer formed on the opening; and

a seed layer formed on the barrier layer, the seed layer having a noble metal or a noble metal-copper alloy, the bottom of the opening exposing copper from the copper interconnect.

24. The apparatus of claim 23 further comprising:

a copper or copper alloy layer formed on the seed layer and filling the opening using an electroplating or electroless bath, the exposed copper at the bottom of the opening functioning as a seed layer for the electroplating or electroless in the opening.