Combined conformal/non-conformal seed layers for metallic interconnects

• US 6,903,016 B2
• Filed: 08/14/2003
• Issued: 06/07/2005
• Est. Priority Date: 10/02/1999
• Status: Expired due to Term

• Current Assignee: Uri Cohen
• Original Assignee: Uri Cohen
• Inventors: Cohen, Uri
• Primary Examiner(s): Hassanzadeh, Parviz
• Application Number:
  US10/640,846
• Publication Number:
  US 20040087171A1
• Time in Patent Office: 663 Days
• Field of Search: 438/687, 438/627, 438/652, 438/763, 438/643, 438/629, 118/719, 118/695, 118/697, 156/345.32, 156/345.31
• US Class Current: 438/687
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 2221/1089 Stacks of seed layers

Abstract

One embodiment of the present invention in a method for making copper interconnects, which method includes: (a) forming a patterned insulating layer on a substrate, the patterned insulating layer including at least one opening and a field surrounding the at least one opening; (b) depositing a barrier layer over the field and inside surfaces of the at least one opening; (c) depositing a non-conformal first copper seed layer over the barrier layer using physical vapor deposition, wherein the first seed layer is thicker than about 500 Å over the field; (d) depositing a conformal second copper seed layer over the first seed layer using chemical vapor deposition; and (e) electroplating a copper layer over the second seed layer.

Claims

1. A method for making metallic interconnects, which method is utilized at a stage of processing a substrate having a patterned insulating layer which includes at least one opening and a field surrounding the at least one opening, the method comprising:

depositing a barrier layer over the field and inside surfaces of the at least one opening;

depositing a non-conformal seed layer and a conformal seed layer over the barrier layer, wherein the non-conformal seed layer is deposited by a PVD technique and the conformal seed layer is deposited by a CVD technique prior to depositing the non-conformal seed layer, and wherein a thickness of the non-conformal seed layer is in a range of about 100 Å

to about 3,000 Å

over the field and a thickness of the conformal seed layer is in a range of about 50 Å

to about 500 Å

over the field, the non-conformal and the conformal seed layers do not seal the at least one opening, thereby leaving enough room for electroplating inside the at least one opening; and

electroplating a metallic layer over the non-conformal and the conformal seed layers, wherein the electroplated metallic layer comprises a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals.

2. The method of claim 1 wherein the thickness of the non-conformal seed layer is in a range of about 300 Å

to about 1,800 Å

over the field and the thickness of the conformal seed layer is in a the range of about 50 Å

to about 300 Å

over the field.

3. The method of claim 1 wherein the non-conformal and the conformal seed layers comprise one or more materials selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals, and wherein the thickness of the non-conformal seed layer over the field is greater than the thickness of the conformal seed layer over the field.

4. A method for depositing seed layers on a substrate, wherein the seed layers comprise a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals, and the substrate includes narrow openings surrounded by a field, the method comprising:

a) adapting a conformal deposition chamber to enable deposition of a conformal seed layer on the substrate;

b) adapting a non-conformal deposition chamber to enable deposition of a non-conformal seed layer on the substrate;

c) configuring an automatic controller with recipe information, the recipe information including deposition sequence, process and timing parameters for operation of the conformal and the non-conformal deposition chambers;

d) operating the automatic controller in accordance with the recipe information to deposit in the conformal deposition chamber a conformal seed layer on the substrate, the conformal seed layer having a thickness of about 50 Å

to about 500 Å

measured over the field;

e) operating the controller in accordance with the recipe information to deposit in the non-conformal deposition chamber a non-conformal seed layer on the substrate, the non-conformal seed layer having a thickness greater than about 500 Å

to about 3000 Å

measured over the field; and

f) operating the controller in accordance with the recipe information to stop the deposition of the conformal seed layer and non-conformal seed layer prior to filling the openings, thereby leaving enough room for electroplating inside the narrow openings.

5. The method of claim 4 further comprising depositing the non-conformal seed layer using physical vapor deposition (PVD).

6. The method of claim 5 further comprising depositing the conformal seed layer using chemical vapor deposition (CVD).

7. The method of claim 4 further comprising operating the controller in accordance with the recipe information to perform the non-conformal deposition before the conformal deposition.

8. A method for depositing seed layers an a substrate, wherein the seed layers comprise a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals, and the substrate includes narrow openings surrounded by a field, the method comprising:

a) adapting a deposition chamber to deposit both a conformal seed layer on the substrate and a non-conformal seed layer on the substrate;

b) configuring an automatic controller with recipe information, the recipe information including deposition sequence, process and timing parameters for operation of the deposition chamber;

c) operating the automatic controller in response to the recipe information to deposit in the deposition chamber a conformal seed layer on the substrate, the conformal seed layer having a thickness of about 50 Å

to about 500 Å

measured over the field;

d) operating the controller in response to the recipe information to deposit in the deposition chamber a non-conformal seed layer on the substrate, the non-conformal seed layer having a thickness greater than about 500 Å

to about 3000 Å

measured over the field; and

e) operating the controller in response to the recipe information to stop the deposition of the conformal seed layer and non-conformal seed layer prior to filling the openings, thereby leaving enough room for electroplating inside the narrow openings.

9. The method of claim 8 wherein the deposition chamber comprises a physical vapor deposition (PVD) chamber.

10. The method of claim 9 further comprising operating the controller in accordance with the recipe information to perform the non-conformal deposition before the conformal deposition.

11. The method of claim 9 further comprising operating the controller in accordance with the recipe information to perform the conformal deposition before the non-conformal deposition.

12. A method for making copper interconnects comprising:

forming a patterned insulating layer on a substrate, the patterned insulating layer including at least one opening and a field surrounding the at least one opening;

depositing a barrier layer over the held and inside surfaces of the at least one opening;

depositing a non-conformal first seed layer comprising copper over the barrier layer using physical vapor deposition, wherein the first seed layer is thicker than about 500 Å

over the field;

depositing a conformal second seed layer comprising copper over the first seed layer using chemical vapor deposition; and

electroplating a metallic layer comprising copper over the second seed layer.

13. A method for making copper interconnects comprising:

forming a patterned insulating layer on a substrate, the patterned insulating layer including at least one opening and a field surrounding the at least one opening;

depositing a barrier layer over the field and inside surfaces of the at least one opening;

depositing a conformal first seed layer comprising copper over the barrier layer using a conformal deposition technique;

depositing a non-conformal second seed layer comprising copper over the first seed layer using a non-conformal deposition technique, the conformal and the non-conformal deposition techniques being different; and

electroplating a metallic layer comprising copper over the second seed layer.

14. The method of claim 13 wherein the thickness of the first seed layer over the field is less than the thickness of the second seed layer over the field.

15. The method of claim 13 wherein the thickness of the first seed layer over the field is in a range from about 50 Å

to about 500 Å

.

16. The method of claim 13 wherein the thickness of the second seed layer over the field is greater than about 500 Å

.

17. A method for making copper interconnects comprising:

forming a patterned insulating layer on a substrate, the patterned insulating layer including at least one opening and a field surrounding the at least one opening;

depositing a barrier layer over the field and inside surfaces of the at least one opening;

depositing a non-conformal first seed layer comprising copper over the barrier layer using a non-conformal deposition technique, wherein the first seed layer is thicker than about 500 Å

over the field;

depositing a conformal second seed layer comprising copper over the first seed layer using a conformal deposition technique; and

electroplating a metallic layer comprising copper over the second seed layer.

18. A method for making copper interconnects comprising:

forming a patterned insulating layer over a substrate, the patterned insulating layer including at least one opening and a field surrounding the at least one opening;

depositing a barrier layer over the patterned insulating layer including over the field and inside surfaces of the at least one opening, the barrier layer comprising a refractory metal or an alloy comprising a refractory metal;

physical vapor depositing a first seed layer comprising copper over the barrier layer, wherein said first copper seed layer is thicker than about 500 Å

over the field;

chemical vapor depositing a second seed layer comprising copper over the first seed layer; and

electroplating a metallic layer comprising copper over the second seed layer.

19. A method for making copper interconnects comprising:

forming a patterned insulating layer on a substrate, the patterned insulating layer including at least one opening and a field surrounding the at least one opening;

depositing a barrier layer over the field and inside surfaces of the at least one opening;

depositing two seed layers comprising copper over the barrier layer using two different deposition techniques, wherein one of said deposition techniques is chemical vapor deposition and the other deposition technique is physical vapor deposition, and wherein the seed layer deposited by the vapor deposition technique is thicker than about 500 Å

over the field; and

electroplating a metallic layer comprising copper over the two seed layers.

20. The method of claim 19 wherein the physical vapor deposition technique is biased substrate sputtering.

21. A method for making metallic interconnects on a substrate, the substrate having a patterned insulating layer which includes at least one opening and a field surrounding the at least one opening, the method comprising:

depositing a barrier layer over said patterned insulating layer including over the field and inside surfaces of the at least one opening;

depositing a least seed layer comprising copper over the barrier layer, said first seed layer comprising a conformal seed layer;

depositing a second seed layer comprising copper over the first seed layer, said second seed layer comprising a non-conformal seed layer, wherein said second seed layer being thicker than said first seed layer over the field; and

electroplating a metallic layer over the second seed layer, wherein the electroplated metallic layer comprises a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals.

22. The method of claim 21 wherein the thickness of the first seed layer over the field is in a range from about 50 Å

to about 500 Å

.

23. The method of claim 21 wherein the thickness of the second seed layer over the field is greater than about 500 Å

.

24. A method for making metallic interconnects on a substrate, the substrate having a patterned insulating layer which includes at least one opening and a field surrounding the at least one opening, the method comprising:

depositing a barrier layer over said patterned insulating layer including over the field and inside surfaces of the at least one opening;

depositing a first seed layer comprising copper over the barrier layer, said first seed layer comprising a non-conformal seed layer, wherein the first seed layer is thicker than about 500 Å

over the field;

depositing by chemical vapor deposition a second seed layer comprising copper over the first seed layer, said second seed layer comprising a conformal seed layer, wherein said first seed layer being thicker than said second seed layer over the field; and

electroplating a metallic layer over the second seed layer, wherein the electroplated metallic layer comprises a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals.

25. The method of claim 24 wherein the first seed layer is deposited using biased substrate sputtering.

26. The method of claim 24 wherein the first seed layer is deposited using self-ionized plasma (SIP) sputtering.

27. A method for making multiple seed layer structure used to fabricate copper interconnects, said method comprising:

forming a patterned insulating layer over a substrate, the patterned insulating layer including at least one opening and a field surrounding the at least one opening;

depositing a barrier layer over the patterned insulating layer including over the field and inside surfaces of the at least one opening, the barrier layer comprising a refractory metal or an alloy comprising a refractory metal;

depositing by physical vapor deposition a first seed layer comprising copper over the barrier layer, wherein said first seed layer is thicker than about 500 Å

over said field;

depositing by chemical vapor deposition a second seed layer comprising copper over the first seed layer, the second seed layer substantially continuously covering inside surfaces of the at least one opening, said first seed layer being thicker than said second seed layer over the field; and

electroplating a metallic layer comprising copper over the second seed layer.