Chemical vapor deposition precursors for deposition of tantalum-based materials
View Patent ↗Tantalum precursors suitable for chemical vapor deposition of tantalum-containing material, e.g., tantalum, TaN, TaSiN, etc., on substrates. The tantalum precursors are substituted cyclopentadienyl tantalum compounds. In one aspect of the invention, such compounds are silylated to constitute tantalum/silicon source reagents. The precursors of the invention are advantageously employed in semiconductor manufacturing applications to form diffusion barriers in connection with copper metallization of the semiconductor device structure.
1. A compound of the formula:
wherein:
n is an integer having a value of from 1 to 5;
each R can be the same or different and each is independently selected fr re the group consisting of D, H, CH 3 , C 2 H 5 , i-C 3 H 7 , C 4 H 9 and Si(R″) 3 wherein each R″ is independently selected from H and C 1 -C 4 alkyl; and
each of R′ can be the same or different and each is independently selected f in the group consisting of D, H, C 1 -C 4 alkyl, and Si(R″) 3 wherein each R″ is independently selected from H and C 1 -C 4 alkyl;
with the provisos that (i) each of the R groups and R′ are not simultaneously all H, and (ii) when each of R′ is H, and n is 1, both R groups are not simultaneously trimethylsilyl.
2. The compound of claim 1 , wherein at least one of R, R′ is Si(R″) 3 wherein each R″ is independently selected from H and C 1 -C 4 alkyl.
3. The compound of claim 1 , wherein at least one of R, R′ is trimethysilyl.
4. The compound of claim 1 , wherein n is 1 for each cyclopentadienyl ring.
5. The compound of claim 4 , wherein R on each cyclopentadienyl ring is trimethylsilyl.
6. The compound of claim 1 , wherein each of the R group and R are independently selected from H, methyl, isopropyl, t-butyl, trimethylsilyl, and t-butylsilyl.
7. The compound of claim 6 , wherein at least one of the R groups and R′ is trimethylsilyl.
8. The compound of claim 7 , wherein n is 1 for each cyclopentadienyl ring.
9. The compound of claim 8 , wherein R on each cyclopentadienyl ring is trimethylsilyl.
10. The compound of claim 1 , wherein each of the R group and R′ are independently selected from H and Si(R″) 3 wherein each R″ is independently selected from H and C 1 -C 4 alkyl.
11. The compound of claim 10 , wherein n is 1 for each cyclopentadienyl ring.
12. The compound of claim 11 , wherein R on each cyclopentadienyl ring is trimethysilyl.
13. The compound of claim 11 , wherein each R is H.
14. The compound of claim 13 , wherein at least one of R′ is Si(R″) wherein each R″ is independently selected from H and C 1 -C 4 alkyl.
15. The compound of claim 14 , wherein one of R 1 , R 2 and R 3 is Si(R″) 3 wherein each R″ is independently selected from H and C 1 -C 4 alkyl.
16. The compound of claim 15 , wherein Si(R″) 3 is alkylsilyl.
17. The compound of claim 16 , wherein said alkylsilyl is t-butylsilyl.
18. A compound of the formula:
wherein TMS is trimethylsilyl and R′ is selected from the group consisting of D, C 1 -C 4 alkyl, and Si(R″) 3 wherein each R″ is independently selected from H and C 1 -C 4 alkyl.
19. A compound of the formula:
20. A method of forming a tantalum-containing material in a substrate, comprising contacting the substrate with a vapor of a tantalum precursor under chemical vapor deposition conditions, wherein said tantalum precursor comprises a compound of the formula:
wherein:
n is an integer having a value of from 1 to 5;
each R can be the same or different and each is independently selected from the group consisting of D, H, CH 3 , C 2 H 5 , i-C 3 H 7 , C 4 H 9 and Si(R″) 3 wherein each R″ is independently selected from H and C 1 -C 4 alkyl; and
each of R′ can be the same or different and each is independently selected from the group consisting of D, H, C 1 -C 4 alkyl, and Si(R″) 3 wherein each R″ is independently elected from H and C 1 -C 4 alkyl.
with the provisios that (i) each of the R groups and R′ are not simultaneously all H, and (ii) when each of R′ is H, and n is 1, both R groups are not simultaneously trimethylsilyl.
21. The method of claim 20 , wherein at least one of R′ is Si(R″) 3 wherein each R″ is independently selected from H and C 1 -C 4 alkyl.
22. The method of claim 20 , wherein at least one of R,R′ is trimethysilyl.
23. The method of claim 20 , wherein n is 1 for each cyclopentadienyl ring.
24. The method of claim 23 , wherein R on each cyclopentadienyl ring is trimethylsilyl.
25. The method of claim 20 , wherein each of the R group and R′ are independently selected from H, methyl, isopropyl, t-butyl, trimethylsilyl, and t-butylsilyl.
26. The method of claim 25 , wherein at least one of the R group and R′ is trimethylsilyl.
27. The method of claim 26 , wherein n is 1 for each cyclopentadienyl ring.
28. The method of claim 27 , wherein R on each cyclopentadienyl ring is trimethylsilyl.
29. The method of claim 20 , wherein each of the R group and R′ are independently selected from H and Si(R″) 3 wherein each R″ is independently selected from H and C 1 -C 4 alkyl.
30. The method of claim 29 , wherein n is 1 for each cyclopentadienyl ring.
31. The method of claim 30 , wherein R on each cyclopentadienyl ring is trimethylsilyl.
32. The method of claim 30 , wherein each R is H.
33. The method of claim 32 , wherein at least one of R′ is Si(R″), wherein each R″ is independently selected from H and C 1 -C 4 alkyl.
34. The method of claim 33 , wherein one of R′ is Si(R″) 3 wherein each R″ is independently selected from H and C 1 -C 4 alkyl.
35. The method of claim 34 , wherein Si(R″) 3 is alkylsilyl.
36. The method of claim 35 , wherein said alkylsilyl is t-butylsilyl.
37. The method of claim 20 , wherein said precursor comprises:
wherein TMS is trimethylsilyl and R′ is selected from the group consisting of D, C 1 -C 4 alkyl, and Si(R″) 3 wherein each R″ is independently selected from H and C 1 -C 4 alkyl.
38. The method of claim 20 , wherein said precursor comprises:
39. The method of claim 20 , wherein the substrate comprises a semiconductor substrate.
40. The method of claim 20 , wherein the substrate comprises a microelectronic device structure.
41. The method of claim 20 , wherein the tantalum-containing material comprises a silicon-doped tantalum material.
42. The method of claim 20 , wherein said chemical vapor deposition conditions comprise a nitrogen atmosphere.
43. The method of claim 20 , wherein said tantalum-containing material comprises TaN.
44. The method of claim 43 , wherein said chemical vapor deposition conditions comprise a nitrogen source for nitrogen in said TaN.
45. The method of claim 20 , wherein said tantalum-containing material comprises TaSiN.
46. The method of claim 45 , wherein said chemical vapor deposition conditions comprise a nitrogen source for nitrogen in said TaSiN.
47. The method of claim 20 , wherein said substrate is a semiconductor substrate, and the tantalum-containing material comprises a material selected from the group consisting of TaN and TaSiN.
48. The method of claim 47 , wherein the tantalum-containing material forms a diffusion barrier layer for copper metallization on said substrate.
49. The method of claim 48 , wherein said copper metallization on said substrate has a line dimension of less than about 0.18 μm.
50. A method of synthesizing a cyclopentadienyl tantalum compound of the formula [(R) n Cp] 2 Ta(R′) 3
wherein:
n is an integer having a value of from 1 to 5;
each R can be the same or different and each is independently selected from the group consisting of D, H, CH 3 , C 2 H 5 , i-C 3 H 7 , C 4 H 9 and Si(R″) 3 wherein each R″ is independently selected from H and C 1 -C 4 alkyl; and
each of R′ can be the same or different and each is independently selected in the group consisting of D, H, C 1 -C 4 alkyl, and Si(R″) 3 wherein each R″ is independently elected from H and C 1 -C 4 alkyl;
with the proviso that each of the R groups and R′ are not simultaneously all H,
said method comprising
reacting tantalum pentachioride with a cyclopentadienyllithium compound of the formula [(R) n Cp] 2 Li in a 1:2 ratio and stepwise addition of sodium borohydride compound of the formula NaBH(R′) 3 to yield said cyclopentadienyl tantalum compound according to the following formula:
51. The method of claim 50 , wherein said reacting step is conduct in a protic solvent medium.
52. The method of claim 51 , wherein said protic solvent medium comprises tetrahydrofuran.
53. The method of claim 50 , wherein said cyclopentadienyl tantalum compound is:
wherein TMS is trimethylsilyl.
54. The method of claim 50 , further comprising reacting said cyclopentadienyl tantalum compound with a silane form a cyclopentadienylsilyltantalum compound.
55. The method of claim 54 , wherein said silane comprises an alkylsiane.
56. The method of claim 55 , wherein said alkylsilane comprises t-butysilane.
57. The method of claim 54 , wherein said cyclopentadienylsilyltantalum compound comprises:
wherein TMS is trimethylsilyl.
58. The method of claim 54 , wherein said cyclopentadienylsilyltantalum compound comprises: