High speed electroplating metallic conductors

• US 9,530,653 B2
• Filed: 01/20/2016
• Issued: 12/27/2016
• 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:
  US15/002,342
• Publication Number:
  US 20160141178A1
• Time in Patent Office: 342 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 inside openings by electrochemical deposition (ECD), said method including steps of: forming at least one opening in a substrate, said at least one opening having an aspect ratio in a range from 8:1 to 28:1; forming at least one barrier layer over the sidewalls of the at least one opening; depositing at least one seed layer over the at least one barrier layer; immersing the substrate in an electrolyte contained in an ECD cell, the ECD cell including at least one anode and a cathode, wherein the electrolyte includes plating metallic ions and at least one inhibitor additive; providing agitation of the electrolyte across the surface of the substrate by moving multiple non-contacting wiping blades relative to the substrate, wherein the agitation facilitates a limiting current density larger by at least an order of magnitude than a limiting current density without the agitation; and applying an average electroplating current density on the substrate, wherein the agitation, the concentrations of the metallic ions and the inhibitor additive, and the average electroplating current density are such as to produce void-free, electroplated metallic filling inside the at least one opening.

Claims

1. A method for void-free filling a metal or an alloy inside openings by electrochemical deposition (ECD), said method comprising steps of:

(a) forming at least one opening and a field surrounding the at least one opening in a substrate, said at least one opening having a bottom and sidewalls surfaces and an aspect ratio in a range from 8;

1 to 28;

1;

(b) forming at least one barrier layer over the field and sidewalls of the at least one opening;

(c) depositing at least one seed layer over the at least one barrier layer;

(d) 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 a portion of the at least one seed layer, 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;

(e) providing agitation of the electrolyte across the surface of the substrate immersed in the electrolyte by moving multiple non-contacting wiping blades relative to the substrate and/or by moving the substrate relative to the multiple non-contacting wiping blades, wherein the agitation of the electrolyte facilitates a limiting current density which is larger by at least an order of magnitude than a limiting current density obtained without the agitation produced by moving the multiple non-contacting wiping blades and/or by moving the substrate;

(f) applying electrical current between the at least one anode and the cathode to generate an average electroplating current density, wherein the agitation, the concentrations of the metallic ions and the at least one inhibitor additive, and the average electroplating current density are such as to produce void-free, electroplated metallic filling inside the at least one opening; and

(g) following electroplating, the electroplated metal or alloy, and any barrier and seed layers above the field, as well as any excess electroplated metal or alloy over the at least one opening, are removed by chemical mechanical polishing (CMP).

2. The method of claim 1 wherein:

(a) the electrolyte comprises at least copper sulfate, sulfuric acid, water, and at least one inhibitor additive, and (b) the average electroplating current density is no more than 120 mA/cm².

3. The method of claim 2 wherein the average electroplating current density is between 15-60 mA/cm².

4. The method of claim 1 wherein the at least one opening has an aspect ratio in a range from 12:

1 to 28;

1.

5. The method of claim 4 wherein:

(a) the electrolyte comprises at least copper sulfate, sulfuric acid, water, and at least one inhibitor additive, and (b) the average electroplating current density is no more than 120 mA/cm².

6. The method of claim 5 wherein the average electroplating current density is between 15-60 mA/cm².

7. The method of claim 1 wherein the at least one opening has an aspect ratio in a range from 16:

1 to 28;

1.

8. The method of claim 7 wherein:

(a) the electrolyte comprises at least copper sulfate, sulfuric acid, water, and at least one inhibitor additive, and (b) the average electroplating current density is no more than 120 mA/cm².

9. The method of claim 8 wherein the average electroplating current density is between 15-60 mA/cm².

10. The method of claim 1 wherein the at least one opening has an aspect ratio in a range from 20:

1 to 28;

1.

11. The method of claim 10 wherein:

(a) the electrolyte comprises at least copper sulfate, sulfuric acid, water, and at least one inhibitor additive, and (b) the average electroplating current density is no more than 120 mA/cm².

12. The method of claim 11 wherein the average electroplating current density is between 15-60 mA/cm².

13. The method of claim 10 wherein the average electroplating current density is between 15-60 mA/cm².

14. The method of claim 1 wherein the movement of the multiple non-contacting wiping blades comprises a linear motion, and the agitation produces a diffusion layer adjacent the substrate, said diffusion layer has a thickness between 2-15 μ

m.

15. A method for void-free filling a metal or an alloy inside openings by electrochemical deposition (ECD), said method comprising steps of:

(a) forming at least one opening and a field surrounding the at least one opening in a substrate, said at least one opening having a bottom and sidewalls surfaces and an aspect ratio in a range from 10;

1 to 28;

1;

(b) forming at least one barrier layer over the field and sidewalls of the at least one opening;

(c) depositing at least one seed layer over the at least one barrier layer;

(d) 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 a portion of the at least one seed layer, 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;

(e) providing agitation of the electrolyte across the surface of the substrate immersed in the electrolyte by moving multiple non-contacting wiping blades relative to the substrate and/or by moving the substrate relative to the multiple non-contacting wiping blades, wherein the agitation of the electrolyte comprises turbulent flow of the electrolyte across the surface of the substrate;

(f) applying electrical current between the at least one anode and the cathode to generate an average electroplating current density, wherein the agitation, the concentrations of the metallic ions and the at least one inhibitor additive, and the average electroplating current density are such as to produce void-free, electroplated metallic filling inside the at least one opening; and

(g) following electroplating, the electroplated metal or alloy, and any barrier and seed layers above the field, as well as any excess electroplated metal or alloy over the at least one opening, are removed by chemical mechanical polishing (CMP).

16. The method of claim 15 wherein the at least one opening has an aspect ratio in a range from 20:

1 to 28;

1.

17. The method of claim 16 wherein the average electroplating current density is between 15-60 mA/cm².

18. The method of claim 15 wherein:

(a) the electrolyte comprises at least copper sulfate, sulfuric acid, water, and at least one inhibitor additive, and (b) the average electroplating current density is no more than 120 mA/cm².

19. The method of claim 18 wherein the average electroplating current density is between 15-60 mA/cm².

20. The method of claim 15 wherein the at least one opening has an aspect ratio in a range from 16:

1 to 28;

1.

21. The method of claim 20 wherein the average electroplating current density is between 15-60 mA/cm².

22. The method of claim 15 wherein the movement of the multiple non-contacting wiping blades comprises a linear motion, and the agitation produces a diffusion layer adjacent the substrate, said diffusion layer has a thickness between 2-15 μ

m.

23. A method for void-free filling a metal or an alloy inside openings by electrochemical deposition (ECD), said method comprising steps of:

(a) forming at least one opening and a field surrounding the at least one opening in a substrate, said at least one opening having a bottom and sidewalls surfaces and an aspect ratio in a range from 10;

1 to 28;

1;

(b) forming at least one barrier layer over the field and sidewalls of the at least one opening;

(c) depositing at least one seed layer over the at least one barrier layer;

(d) 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 a portion of the at least one seed layer, 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;

(e) providing agitation of the electrolyte across the surface of the substrate immersed in the electrolyte by moving multiple non-contacting wiping blades relative to the substrate and/or by moving the substrate relative to the multiple non-contacting wiping blades, wherein the agitation produces a diffusion layer adjacent the substrate, said diffusion layer having a thickness between 2-15 μ

m;

(f) applying electrical current between the at least one anode and the cathode to generate an average electroplating current density, wherein the agitation, the concentrations of the metallic ions and the at least one inhibitor additive, and the average electroplating current density are such as to produce void-free, electroplated metallic filling inside the at least one opening; and

(g) following electroplating, the electroplated metal or alloy, and any barrier and seed layers above the field, as well as any excess electroplated metal or alloy over the at least one opening, are removed by chemical mechanical polishing (CMP).

24. The method of claim 23 wherein:

(a) the electrolyte comprises at least copper sulfate, sulfuric acid, water, and at least one inhibitor additive, and (b) the average electroplating current density is no more than 120 mA/cm².

25. The method of claim 24 wherein the average electroplating current density is between 15-60 mA/cm².

26. The method of claim 24 wherein the at least one opening has an aspect ratio in a range from 16:

1 to 28;

1.

27. The method of claim 26 wherein the movement of the multiple non-contacting wiping blades comprises a linear motion, and the diffusion layer has a thickness between 2-10 μ

m.

28. The method of claim 23 wherein the at least one opening has an aspect ratio in a range from 20:

1 to 28;

1.

29. The method of claim 28 wherein:

(a) the electrolyte comprises at least copper sulfate, sulfuric acid, water, and at least one inhibitor additive, and (b) the average electroplating current density is no more than 120 mA/cm².

30. The method of claim 29 wherein the average electroplating current density is between 15-60 mA/cm².

31. The method of claim 28 wherein the average electroplating current density is between 15-60 mA/cm².

32. The method of claim 28 wherein said diffusion layer has a thickness between 2-10 μ

m.

33. The method of claim 23 wherein said diffusion layer has a thickness between 2-10 μ

m.

34. The method of claim 23 wherein the movement of the multiple non-contacting wiping blades comprises a linear motion, and the diffusion layer has a thickness between 2-10 μ

m.