Electroplated metallic conductors

• US 9,273,409 B2
• Filed: 05/06/2015
• Issued: 03/01/2016
• Est. Priority Date: 03/30/2001
• Status: Active Grant

• Current Assignee: Uri Cohen
• Original Assignee: Uri Cohen
• Inventors: Cohen, Uri
• Primary Examiner(s): Wilkins, III, Harry D
• Application Number:
  US14/705,813
• Publication Number:
  US 20150233005A1
• Time in Patent Office: 300 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C25D 21/10 Agitating of electrolytes; Moving of racks
• CPC Class Codes: C25D 5/022 using masking means
• CPC Class Codes: C25D 5/026 using locally applied jets of electrolyte
• CPC Class Codes: C25D 5/028 one side electroplating, e.g. substrate conveyed in a bath with inhibited background plating
• CPC Class Codes: C25D 5/08 Electroplating with moving electrolyte e.g. jet electroplating using locally applied jets of electrolyte C25D5/026
• CPC Class Codes: C25D 5/611 Smooth layers
• CPC Class Codes: C25D 5/627 Electroplating characterised by the visual appearance of the layers, e.g. colour, brightness or mat appearance
• 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 21/3212 by chemical mechanical polishing [CMP]
• CPC Class Codes: H01L 21/7684 Smoothing; Planarisation
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• 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: H01L 21/76879 by selective deposition of conductive material in the vias, e.g. selective C.V.D. on semiconductor material, plating plating on semiconductors in general H01L21/288
• CPC Class Codes: H01L 21/7688 by deposition over sacrificial masking layer, e.g. lift-off lift-off per se H01L21/0272
• CPC Class Codes: H01L 23/481 Internal lead connections, e.g. via connections, feedthrough structures
• CPC Class Codes: H01L 23/5226 Via connections in a multilevel interconnection structure
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding 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
• CPC Class Codes: H05K 3/06 : the conductive material being removed chemically or electrolytically, e.g. by photo-etch process semi-additive methods H05K3/108
• CPC Class Codes: H05K 3/107 : by filling grooves in the support with conductive material H05K3/045, H05K3/101, H05K3/1258 and H05K3/465 take precedence
• CPC Class Codes: H05K 3/423 : characterised by electroplating method

Abstract

One embodiment is a method for producing void-free electroplated metallic conductors, the method including steps of: (a) providing a substrate having an insulating mask formed over a metallic seed layer, said insulating mask having at least one opening formed therein, wherein inside the at least one opening only the bottom surface includes exposed metallic seed layer; (b) immersing the substrate in an electrolyte contained in an electrochemical deposition (ECD) cell, the ECD cell including at least one anode and a cathode, wherein the cathode includes at least the exposed metallic seed layer at the bottom of the at least one opening, and wherein the electrolyte includes plating metallic ions and at least one inhibitor additive, said metallic ions and said at least one inhibitor additive having concentrations; (c) providing agitation of the electrolyte across the surface of the substrate; (d) electroplating inside the at least one opening wherein (i) the agitation and the concentrations of the plating metallic ions and the at least one inhibitor additive produce void-free electroplated metal or alloy inside the at least one opening when applying to the substrate an average electroplating current density between 45-250 mA/cm², and (ii) said electroplated metal or alloy is a material selected from a group consisting of Cu, Ag, Cu alloys, and Ag alloys; and (e) removing the insulating mask, and then removing the metallic seed layer which was covered by the insulating mask during step (d).

Claims

1. A method for producing a void-free electroplated metallic conductor, the method comprising steps of:

(a) providing a substrate having an insulating mask formed over a metallic seed layer, said insulating mask having at least one opening formed therein, said at least one opening having a bottom and sidewall surfaces, wherein inside the at least one opening only the bottom surface comprises exposed metallic seed layer;

(b) immersing the substrate in an electrolyte contained in an electrochemical deposition (ECD) cell, the ECD cell comprising at least one anode and a cathode, wherein the cathode comprises at least the exposed metallic seed layer at the bottom of the at least one opening, and wherein the electrolyte comprises plating metallic ions and at least one inhibitor additive, said metallic ions and said at least one inhibitor additive having concentrations;

(c) providing agitation of the electrolyte across the surface of the substrate immersed in the electrolyte;

(d) electroplating inside the at least one opening;

wherein (i) the agitation and the concentrations of the plating metallic ions and the at least one inhibitor additive produce void-free electroplated metal or alloy inside the at least one opening when applying to the substrate an average electroplating current density between 45-250 mA/cm² during most or all of the electroplating, and (ii) said electroplated metal or alloy is a material selected from a group consisting of Cu, and Cu alloys; and

(e) removing the insulating mask, and then removing the metallic seed layer which was covered by the insulating mask during step (d).

2. The method of claim 1 wherein the average electroplating current density is between 45-120 mA/cm².

3. The method of claim 2 wherein the agitation of the electrolyte comprises turbulent flow of the electrolyte across the surface of the substrate.

4. The method of claim 3 wherein at least a portion of the agitation of the electrolyte is produced by moving multiple non-contacting wiping blades, or multiple non-contacting wiping pads, relative to the substrate, and/or by moving the substrate relative to multiple non-contacting wiping blades, or relative to multiple non-contacting wiping pads.

5. The method of claim 4 wherein the agitation of the electrolyte produces an average diffusion layer thickness between 2-40 μ

m.

6. The method of claim 4 wherein the agitation of the electrolyte produces an average diffusion layer thickness between 2-20 μ

m.

7. The method of claim 4 wherein the agitation of the electrolyte produces an average diffusion layer thickness between 2-10 μ

m.

8. The method of claim 2 wherein at least a portion of the agitation of the electrolyte is produced by moving multiple non-contacting wiping blades, or multiple non-contacting wiping pads, relative to the substrate, and/or by moving the substrate relative to multiple non-contacting wiping blades, or relative to multiple non-contacting wiping pads.

9. The method of claim 8 wherein the agitation of the electrolyte produces an average diffusion layer thickness between 2-40 μ

m.

10. The method of claim 8 wherein the agitation of the electrolyte produces an average diffusion layer thickness between 2-20 μ

m.

11. The method of claim 8 wherein the agitation of the electrolyte produces an average diffusion layer thickness between 2-10 μ

m.

12. The method of claim 8 wherein the substrate comprises a 300 mm wafer.

13. The method of claim 1 wherein the average electroplating current density is between 60-250 mA/cm².

14. The method of claim 1 wherein the average electroplating current density is between 60-120 mA/cm².

15. The method of claim 1 wherein the agitation of the electrolyte comprises turbulent flow of the electrolyte across the surface of the substrate.

16. The method of claim 15 wherein at least a portion of the agitation of the electrolyte is produced by moving multiple non-contacting wiping blades, or multiple non-contacting wiping pads, relative to the substrate, and/or by moving the substrate relative to multiple non-contacting wiping blades, or relative to multiple non-contacting wiping pads.

17. The method of claim 16 wherein the agitation of the electrolyte produces an average diffusion layer thickness between 2-40 μ

m.

18. The method of claim 16 wherein the agitation of the electrolyte produces an average diffusion layer thickness between 2-20 μ

m.

19. The method of claim 16 wherein the agitation of the electrolyte produces an average diffusion layer thickness between 2-10 μ

m.

20. The method of claim 15 wherein at least a portion of the agitation of the electrolyte is produced by electrolyte jets impinging on the substrate in a direction that is substantially normal to the substrate, and moving the substrate relative to the jets and/or moving the jets relative to the substrate.

21. The method of claim 15 wherein the agitation of the electrolyte produces an average diffusion layer thickness between 2-40 μ

m.

22. The method of claim 1 wherein at least a portion of the agitation of the electrolyte is produced by moving multiple non-contacting wiping blades, or multiple non-contacting wiping pads, relative to the substrate, and/or by moving the substrate relative to multiple non-contacting wiping blades, or relative to multiple non-contacting wiping pads.

23. The method of claim 22 wherein the agitation of the electrolyte produces an average diffusion layer thickness between 2-40 μ

m.

24. The method of claim 22 wherein the agitation of the electrolyte produces an average diffusion layer thickness between 2-20 μ

m.

25. The method of claim 22 wherein the agitation of the electrolyte produces an average diffusion layer thickness between 2-10 μ

m.

26. The method of claim 22 wherein the substrate comprises a 300 mm wafer.

27. The method of claim 1 wherein at least a portion of the agitation of the electrolyte is produced by electrolyte jets impinging on the substrate in a direction that is substantially normal to the substrate, and moving the substrate relative to the jets and/or moving the jets relative to the substrate.