Surface preparation process for damascene copper deposition

1. A method of metallizing a substrate comprising an interconnect feature in the manufacture of a microelectronic device, wherein the interconnect feature comprises a bottom, a sidewall, and a top opening having a diameter, D, the method comprising:

depositing a barrier layer on the bottom and the sidewall of the interconnect feature, the barrier layer comprising a metal selected from the group consisting of ruthenium, tungsten, tantalum, titanium, iridium, rhodium, and combinations thereof;

contacting the substrate comprising the interconnect feature comprising the bottom and sidewall having the barrier layer thereon with an aqueous composition comprising a reducing agent for removal of oxide that may have formed on the surface of the barrier metal; and

after contact of said substrate with said aqueous solution, depositing copper metal onto the bottom and the sidewall of the interconnect feature having the barrier layer thereon.

2. The method of claim 1 wherein the barrier layer comprises ruthenium, and the barrier layer is deposited by chemical vapor deposition.

3. The method of claim 1 wherein the barrier layer comprises ruthenium, and the barrier layer is deposited by physical vapor deposition.

4. The method of claim 1 wherein the barrier layer comprises ruthenium, and the barrier layer is deposited by atomic layer deposition.

5. The method of claim 1 wherein the barrier layer comprises an underlayer comprising a material selected from the group consisting of ruthenium, tungsten, tantalum, tantalum nitrogen composite, titanium, titanium nitrogen composite, tungsten, and tungsten nitrogen composite, and ruthenium, and a surface layer comprising a material selected from the group consisting of ruthenium, tungsten, iridium, rhodium, platinum, and combinations thereof.

6. The method of claim 5 wherein the surface layer comprises ruthenium, and the surface layer is deposited by chemical vapor deposition.

7. The method of claim 5 wherein the surface layer comprises ruthenium, and the surface layer is deposited by physical vapor deposition.

8. The method of claim 5 wherein the surface layer comprises ruthenium, and the surface layer is deposited by atomic layer deposition.

9. The method of claim 1 wherein the reducing agent is selected from the group consisting of borohydrides (sodium, potassium, cyano, trimethoxy, and tetramethylammonium, among others), monomethyl amine borane, isopropyl amine borane, tert-butylamine borane, dimethyl amine borane (DMAB), diethyl amine borane (DEAB), trimethyl amine borane, triethyl amine borane, triisopropyl amine borane, pyridine borane, morpholine borane, 4-methylmorpholine borane, hypophosphorus acid, ammonium hypophosphite, sodium hypophosphite, sodium hypophosphite monohydrate, potassium hypophosphite, tetramethylammonium hypophosphite, tetraethylammonium hypophosphite, tetrapropylammonium hypophosphite, tetrabutylammonium hypophosphite, calcium hypophosphite, manganese hypophosphite, 1-ethylpiperidine hypophosphite, anilinium hypophosphite, and combinations thereof.

10. The method of claim 1 wherein the reducing agent comprises a first reducing agent component and a second reducing agent component, wherein:

the first reducing agent component is selected from the group consisting of borohydrides (sodium, potassium, cyano, trimethoxy, and tetramethylammonium, among others), monomethyl amine borane, isopropyl amine borane, tert-butylamine borane, dimethyl amine borane (DMAB), diethyl amine borane (DEAB), trimethyl amine borane, triethyl amine borane, triisopropyl amine borane, pyridine borane, morpholine borane, 4-methylmorpholine borane, and combinations thereof; and

the second reducing agent component is selected from the group consisting of hypophosphorus acid, ammonium hypophosphite, sodium hypophosphite, sodium hypophosphite monohydrate, potassium hypophosphite, tetramethylammonium hypophosphite, tetraethylammonium hypophosphite, tetrapropylammonium hypophosphite, tetrabutylammonium hypophosphite, calcium hypophosphite, manganese hypophosphite, 1-ethylpiperidine hypophosphite, anilinium hypophosphite, and combinations thereof.

11. The method of claim 1 wherein the aqueous composition comprising a reducing agent has a pH between about 8 and about 13.

12. The method of claim 1 wherein the aqueous composition further comprises a surfactant.

13. The method of claim 12 wherein the surfactant is an anionic surfactant selected from the group consisting of alkyl phosphonates, alkyl ether phosphates, alkyl sulfates, alkyl ether sulfates, alkyl sulfonates, alkyl ether sulfonates, carboxylic acid ethers, carboxylic acid esters, alkyl aryl sulfonates, aryl alkylether sulfonates, aryl sulfonates, sulfosuccinates, and combinations thereof.

14. The method of claim 12 wherein the surfactant is selected from the group consisting of sodium lauryl sulfate, sodium laureth sulfate (1 EO), sodium laureth sulfate (2 EO), sodium laureth, sodium laureth sulfate (3 EO), ammonium lauryl sulfate, ammonium laureth sulfate, ammonium laureth sulfate (3 EO), TEA-lauryl sulfate, TEA-laureth sulfate, MEA-lauryl sulfate, MEA-laureth sulfate, potassium lauryl sulfate, potassium laureth sulfate, sodium decyl sulfate, sodium octyl/decyl sulfate, sodium 2-ethylhexyl sulfate, sodium octyl sulfate, sodium nonoxynol-4 sulfate, sodium nonoxynol-6 sulfate, sodium cumene sulfate, ammonium nonoxynol-6 sulfate, polyether sulfates, and combinations thereof.

15. The method of claim 12 wherein the surfactant is selected from the group consisting of sodium α-olefin sulfonate, ammonium xylene sulfonate, sodium xylene sulfonate, sodium toluene sulfonate, dodecyl benzene sulfonate, lignosulfonates, disodium lauryl sulfosuccinate, disodium laureth sulfosuccinate, and combinations thereof.

16. The method of claim 1 wherein the copper metal is deposited by contacting the substrate with an electroless copper deposition composition to thereby deposit the copper metal by electroless copper deposition.

17. The method of claim 1 wherein the copper metal is deposited by contacting the substrate with an electrolytic copper deposition composition and applying an external source of electrons to thereby deposit the copper metal by electrolytic copper deposition.

18. The method of claim 1 wherein the copper metal is deposited according to the following steps in order (1) contacting the substrate with an electroless copper deposition composition to thereby deposit the copper metal by electroless copper deposition (2) contacting the substrate with an electrolytic copper deposition composition and (3) applying an external source of electrons to thereby deposit the copper metal by electrolytic copper deposition.

19. A method of metallizing an interconnect feature in a microelectronic device substrate, wherein the interconnect feature comprises a bottom, a sidewall, and a top opening having a diameter, D, the method comprising:

depositing a barrier layer on the bottom and the sidewall of the interconnect feature, the barrier layer comprising a metal selected from the group consisting of ruthenium, tungsten, tantalum, titanium, iridium, rhodium, and combinations thereof;

contacting the substrate comprising the interconnect feature comprising the bottom and sidewall having the barrier layer thereon with an aqueous composition comprising a reducing agent for removal of oxide that may have formed on the surface of the barrier metal; and

after contact of said substrate with said aqueous solution, contacting the substrate with an electroless copper deposition composition to electrolessly deposit copper metal in the interconnect feature and thereby metallize the interconnect feature.

20. A method as set forth in claim 1 wherein an oxide that has formed on said barrier layer is removed by contact of said substrate comprising said barrier with said aqueous solution containing a reducing agent.

21. A method as set forth in claim 1 wherein said substrate comprising the interconnect feature comprising the bottom and sidewall having the barrier layer thereon is contacted with an aqueous composition comprising a reducing agent for removal of oxide that may have formed on the surface of the barrier layer due to exposure to ambient atmosphere.

22. A method as set forth in claim 19 wherein said substrate comprising the interconnect feature comprising the bottom and sidewall having the barrier layer thereon is contacted with an aqueous composition comprising a reducing agent for removal of oxide that may have formed on the surface of the barrier layer due to exposure to ambient atmosphere.

23. A method of metallizing a substrate comprising an interconnect feature in the manufacture of a microelectronic device, wherein the interconnect feature comprises a bottom, a sidewall, and a top opening having a diameter, D, the method comprising:

contacting the substrate comprising the interconnect feature comprising the bottom and sidewall having the barrier layer thereon with an aqueous composition comprising a reducing agent for removal of oxide that may have formed on the surface of the barrier metal;

wherein said substrate prior to said contacting is characterized by having a deposited barrier layer on the bottom and the sidewall of the interconnect feature, and the barrier layer comprising a metal selected from the group consisting of ruthenium, tungsten, tantalum, titanium, iridium, rhodium, and combinations thereof; and

after contact of said substrate with said aqueous solution, depositing copper metal onto the bottom and the sidewall of the interconnect feature having the barrier layer thereon.

24. The method of claim 23 wherein the barrier layer comprises an underlayer comprising a material selected from the group consisting of ruthenium, tungsten, tantalum, tantalum nitrogen composite, titanium, titanium nitrogen composite, tungsten, and tungsten nitrogen composite, and ruthenium, and a surface layer comprising a material selected from the group consisting of ruthenium, tungsten, iridium, rhodium, platinum, and combinations thereof.

25. The method of claim 23 wherein the reducing agent is selected from the group consisting of borohydrides (sodium, potassium, cyano, trimethoxy, and tetramethylammonium, among others), monomethyl amine borane, isopropyl amine borane, tert-butylamine borane, dimethyl amine borane (DMAB), diethyl amine borane (DEAB), trimethyl amine borane, triethyl amine borane, triisopropyl amine borane, pyridine borane, morpholine borane, 4-methylmorpholine borane, hypophosphorus acid, ammonium hypophosphite, sodium hypophosphite, sodium hypophosphite monohydrate, potassium hypophosphite, tetramethylammonium hypophosphite, tetraethylammonium hypophosphite, tetrapropylammonium hypophosphite, tetrabutylammonium hypophosphite, calcium hypophosphite, manganese hypophosphite, 1-ethylpiperidine hypophosphite, anilinium hypophosphite, and combinations thereof.

26. The method of claim 23 wherein the reducing agent comprises a first reducing agent component and a second reducing agent component, wherein:

the first reducing agent component is selected from the group consisting of borohydrides (sodium, potassium, cyano, trimethoxy, and tetramethylammonium, among others), monomethyl amine borane, isopropyl amine borane, tert-butylamine borane, dimethyl amine borane (DMAB), diethyl amine borane (DEAB), trimethyl amine borane, triethyl amine borane, triisopropyl amine borane, pyridine borane, morpholine borane, 4-methylmorpholine borane, and combinations thereof; and

the second reducing agent component is selected from the group consisting of hypophosphorus acid, ammonium hypophosphite, sodium hypophosphite, sodium hypophosphite monohydrate, potassium hypophosphite, tetramethylammonium hypophosphite, tetraethylammonium hypophosphite, tetrapropylammonium hypophosphite, tetrabutylammonium hypophosphite, calcium hypophosphite, manganese hypophosphite, 1-ethylpiperidine hypophosphite, anilinium hypophosphite, and combinations thereof.

27. The method of claim 23 wherein the aqueous composition comprising a reducing agent has a pH between about 8 and about 13.

28. The method of claim 23 wherein the aqueous composition further comprises an anionic surfactant selected from the group consisting of alkyl phosphonates, alkyl ether phosphates, alkyl sulfates, alkyl ether sulfates, alkyl sulfonates, alkyl ether sulfonates, carboxylic acid ethers, carboxylic acid esters, alkyl aryl sulfonates, aryl alkylether sulfonates, aryl sulfonates, sulfosuccinates, and combinations thereof.

29. The method of claim 23 wherein the aqueous composition further comprises a surfactant selected from the group consisting of sodium lauryl sulfate, sodium laureth sulfate (1 EO), sodium laureth sulfate (2 EO), sodium laureth, sodium laureth sulfate (3 EO), ammonium lauryl sulfate, ammonium laureth sulfate, ammonium laureth sulfate (3 EO), TEA-lauryl sulfate, TEA-laureth sulfate, MEA-lauryl sulfate, MEA-laureth sulfate, potassium lauryl sulfate, potassium laureth sulfate, sodium decyl sulfate, sodium octyl/decyl sulfate, sodium 2-ethylhexyl sulfate, sodium octyl sulfate, sodium nonoxynol-4 sulfate, sodium nonoxynol-6 sulfate, sodium cumene sulfate, ammonium nonoxynol-6 sulfate, polyether sulfates, and combinations thereof.

30. The method of claim 23 wherein the aqueous composition further comprises a surfactant selected from the group consisting of sodium α-olefin sulfonate, ammonium xylene sulfonate, sodium xylene sulfonate, sodium toluene sulfonate, dodecyl benzene sulfonate, lignosulfonates, disodium lauryl sulfosuccinate, disodium laureth sulfosuccinate, and combinations thereof.

31. The method of claim 23 wherein the copper metal is deposited by contacting the substrate with an electroless copper deposition composition to thereby deposit the copper metal by electroless copper deposition.

32. The method of claim 23 wherein the copper metal is deposited by contacting the substrate with an electrolytic copper deposition composition and applying an external source of electrons to thereby deposit the copper metal by electrolytic copper deposition.

33. The method of claim 23 wherein the copper metal is deposited according to the following steps in order (1) contacting the substrate with an electroless copper deposition composition to thereby deposit the copper metal by electroless copper deposition (2) contacting the substrate with an electrolytic copper deposition composition and (3) applying an external source of electrons to thereby deposit the copper metal by electrolytic copper deposition.