Capping of metal interconnects in integrated circuit electronic devices

• US 7,393,781 B2
• Filed: 09/10/2007
• Issued: 07/01/2008
• Est. Priority Date: 06/14/2004
• Status: Expired due to Term

• Current Assignee: MacDermid Enthone Inc. (Element Solutions Inc)
• Original Assignee: Enthone Incorporated (Element Solutions Inc)
• Inventors: Chen, Qingyun, Hurtubise, Richard, Yakobson, Eric, Witt, Christian
• Primary Examiner(s): NGUYEN, CUONG QUANG
• Application Number:
  US11/852,513
• Publication Number:
  US 20070298609A1
• Time in Patent Office: 295 Days
• Field of Search: 438/653, 438629-631, 438678-687
• US Class Current: 438/653
• CPC Class Codes: H01L 21/288 from a liquid, e.g. electrolytic deposition
• CPC Class Codes: H01L 21/76846 Layer combinations
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: H01L 2224/05006 Dual damascene structure
• CPC Class Codes: H01L 24/03 Manufacturing methods
• CPC Class Codes: H01L 24/05 of an individual bonding area
• 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 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/0102 Calcium [Ca]
• CPC Class Codes: H01L 2924/01023 Vanadium [V]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01042 Molybdenum [Mo]
• CPC Class Codes: H01L 2924/01044 Ruthenium [Ru]
• CPC Class Codes: H01L 2924/01045 Rhodium [Rh]
• CPC Class Codes: H01L 2924/01047 Silver [Ag]
• CPC Class Codes: H01L 2924/0105 Tin [Sn]
• CPC Class Codes: H01L 2924/01051 : Antimony [Sb]
• CPC Class Codes: H01L 2924/01072 : Hafnium [Hf]
• CPC Class Codes: H01L 2924/01073 : Tantalum [Ta]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01075 : Rhenium [Re]
• CPC Class Codes: H01L 2924/01076 : Osmium [Os]
• CPC Class Codes: H01L 2924/01077 : Iridium [Ir]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/01084 : Polonium [Po]
• CPC Class Codes: H01L 2924/01327 : Intermediate phases, i.e. intermetallics compounds
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15747 : Copper [Cu] as principal constituent
• CPC Class Codes: H05K 2203/072 : Electroless plating, e.g. finish plating or initial plating
• CPC Class Codes: H05K 2203/1476 : Same or similar kind of process performed in phases, e.g. coarse patterning followed by fine patterning
• 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 3/244 : Finish plating of conductors, especially of copper conductors, e.g. for pads or lands selective plating methods H05K3/243; finish plating of conductors made by printing techniques H05K3/246; solder as finish H05K3/3457, e.g. by plating H05K3/3473

Abstract

A multilayer metal cap over a metal-filled interconnect feature in a dielectric layer for incorporation into a multilayer integrated circuit device, and a method for forming the cap.

Claims

1. A method for forming a multilayer metal cap over a metal-filled interconnect feature in a dielectric layer for incorporation into a multilayer integrated circuit device comprising:

depositing a first cobalt-based metal cap layer over the metal-filled interconnect feature in a first electroless deposition process employing a first electroless solution comprising a source of Co ions and a borane-based reducing agent and wherein the first metal cap layer is substantially continuous and has a thickness between about 5 angstroms and about 50 angstroms; and

depositing a second cobalt-based metal cap layer over the first metal cap layer in a second electroless deposition process distinct from the first deposition process wherein the second deposition process is electroless and employs a second electroless solution which comprises a source of Co ions and a reducing agent, and which is distinct from, and prepared separately from, the first electroless solution, to thereby form the multilayer metal cap as a permanent component distinct from the metal-filled interconnect feature.

2. The method of claim 1 wherein the metal-filled interconnect feature is a Cu-filled interconnect feature.

3. The method of claim 1 wherein the first cobalt-based metal cap layer has a thickness between about 5 angstroms and about 20 angstroms.

4. The method of claim 1 wherein the first cobalt-based metal cap layer is a cobalt-based alloy selected from the group consisting of Co—

W—

B, Co—

W—

B—

P, Co—

B—

P, Co—

B, Co—

Mo—

B, Co—

W—

Mo—

B, and Co—

W—

Mo—

B—

P.

5. The method of claim 1 wherein the first cobalt-based metal cap layer is a cobalt-based alloy selected from the group consisting of Co—

W—

B, Co—

W—

B—

P, Co—

B—

P, and Co—

B.

6. The method of claim 1 wherein the second cobalt-based metal cap layer has a thickness between about 60 angstroms about 100 angstroms.

7. The method of claim 1 wherein the second cobalt-based metal cap layer has a thickness greater than about 100 angstroms.

8. The method of claim 1 wherein the second cobalt-based metal cap layer has a thickness between about 100 angstroms and about 300 angstroms.

9. The method of claim 1 wherein the second cobalt-based metal cap layer is a cobalt-based alloy selected from the group consisting of Co—

W—

P, Co—

W—

B, Co—

W—

B—

P, Co—

B—

P, Co—

B, Co—

Mo—

B, Co—

W—

Mo—

B, Co—

W—

Mo—

B—

P, and Co—

Mo—

P.

10. The method of claim 1 further comprising the step of depositing a discontinuous, substantially uncoalesced Co seed onto the metal-filled interconnect feature prior to depositing the first cobalt-based metal cap layer.

11. The method of claim 1 further comprising the step of depositing a third metal cap layer over the second cobalt-based metal cap layer in a third deposition process distinct from the second deposition process.

12. A method for forming a multilayer metal cap over a metal-filled interconnect feature in a dielectric layer for incorporation into a multilayer integrated circuit device comprising:

depositing a first metal cap layer over the metal-filled interconnect feature in a first noble metal immersion deposition process employing a noble metal immersion solution comprising a source of noble metal ions;

depositing a second cobalt-based metal cap layer over the first metal cap layer in a first electroless deposition process distinct from the first deposition process, wherein the first electroless deposition process employs a first electroless deposition solution comprising a source of Co ions and a reducing agent; and

depositing a third cobalt-based metal cap layer over the second metal cap layer in a second electroless deposition process distinct from the first electroless deposition process, wherein the second electroless deposition process employs a second electroless deposition solution comprising a source of Co ions and a reducing agent, which is distinct from, and prepared separately from, the second electroless deposition solution, to thereby form the multilayer metal cap as a permanent component distinct from the metal-filled interconnect feature.

13. The method of claim 12 wherein the metal-filled interconnect feature is a Cu-filled interconnect feature.

14. The process of claim 12 wherein depositing the first metal cap layer comprises depositing a Pd layer which is discontinuous and substantially uncoalesced, and functions as a seed layer for the second deposition process.

15. The process of claim 12 wherein depositing the first metal cap layer comprises depositing a Pd layer which is substantially continuous and has a thickness between about 5 and about 50 angstroms.

16. The method of claim 12 wherein the second cobalt-based metal cap layer has a thickness between about 5 angstroms and about 50 angstroms.

17. The method of claim 12 wherein the second cobalt-based metal cap layer has a thickness between about 5 angstroms and about 20 angstroms.

18. The method of claim 12 wherein the second cobalt-based metal cap layer has a thickness between about 60 angstroms about 100 angstroms.

19. The method of claim 12 wherein the second cobalt-based metal cap layer has a thickness greater than about 100 angstroms.

20. The method of claim 12 wherein the second cobalt-based metal cap layer has a thickness between about 100 angstroms and about 300 angstroms.

21. The method of claim 12 wherein the third cobalt-based metal cap layer has a thickness between about 60 angstroms about 100 angstroms.

22. The method of claim 12 wherein the third cobalt-based metal cap layer has a thickness greater than about 100 angstroms.

23. The method of claim 12 wherein the third cobalt-based metal cap layer has a thickness between about 100 angstroms and about 300 angstroms.

24. The method of claim 12 further comprising depositing a fourth metal cap layer over the third cobalt-based metal cap layer in a third electroless deposition process distinct from the second electroless deposition process.