Dry etch stop process for eliminating electrical shorting in MRAM device structures
View Patent ↗The present invention relates generally to semiconductor fabrication and particularly to fabricating magnetic tunnel junction devices. In particular, this invention relates to a method for using the dielectric layer in tunnel junctions as an etch stop layer to eliminate electrical shorting that can result from the patterning process.
1. A process for fabricating a magnetic junction memory device comprising:
(a) providing a substrate;
(b) forming an insulating layer over the substrate;
(c) forming a top metal layer over the insulating layer; and
(d) applying a non-reactive gas and a bias to the substrate with bias power between the sputter threshold of the top metal layer and the insulating layer to selectively remove the top metal layer with respect to the underlying insulating layer.
2. A process as in claim 1 wherein the non-reactive gas is Ar, He, Ne, Kr, N 2 , or Xe, or any combination thereof.
3. A process as in claim 1 further comprising the step of forming a bottom metal layer under the insulating layer.
4. A process as in claim 1 wherein a plasma is formed with the non-reactive gas.
5. A process as in claim 1 wherein the insulating layer comprises aluminum oxide, magnesium oxide, or any insulating oxide.
6. A process as in claim 1 wherein the top metal layer comprises a magnetic layer, part of an MRAM stack structure, or one or more layers of NiFe, CoFe, CoNiFe, and CoFeB.
7. A process for fabricating a magnetic junction memory device comprising:
(a) providing a substrate;
(b) forming an insulating layer over the substrate;
(c) forming a top layer over the insulating layer; and
(d) applying a physical sputter etch process using a mixture of a non-reactive gas and <1% of an oxygen-containing gas to selectively remove the top layer with respect to the underlying insulating layer,
wherein the oxygen-containing gas is introduced into the process from the sputtering of a solid source of an oxygen-containing solid, and
wherein the solid source comprises alumina or quartz.
8. A process as in claim 7 wherein the non-reactive gas is Ar, He, Ne, Kr, N 2 , or Xe, or any combination thereof.
9. A process as in claim 7 wherein the oxygen-containing gas is O, O 2 , N 2 O, NO, air, CO, or any combination thereof.
10. A process as in claim 7 wherein the mixture is 99.9% Ar and 0.1% O 2 .
11. A process as in claim 7 wherein the mixture of a non-reactive gas and an oxygen-containing gas is introduced through a first flow controller and a non-reactive gas is introduced through a second flow controller.
12. A process as in claim 7 wherein the first flow controller provides 80 sccm of argon and 0.08 sccm of O2 and the second flow controller provides 270 sccm of argon.
13. A process as in claim 7 wherein the non-reactive gas is in the range of 10 to 350 sccm and the oxygen-containing gas is in the range of 0.02 to 0.15 sccm.
14. A process as in claim 7 wherein the oxygen-containing gas is introduced from controlled leakage.
15. A process as in claim 7 further comprising the step of forming a bottom metal layer under the insulating layer.
16. A process as in claim 7 wherein a plasma is formed with the non-reactive gas.
17. A process as in claim 7 wherein the insulating layer comprises aluminum oxide, magnesium oxide, or any insulating oxide.
18. A process as in claim 7 wherein the top layer comprises a magnetic layer, part of an MRAM stack structure, or one or more layers of NiFe, CoFe, CoNiFe, and CoFeB.
19. A process for fabricating a magnetic junction memory device comprising:
(a) providing a substrate;
(b) forming an insulating layer over the substrate;
(c) forming a top metal layer over the insulating layer; and
(d) applying a physical sputter etch process using a mixture of a non-reactive gas and <1% of an oxygen-containing gas and a bias to the substrate with bias power between the sputter threshold of the top metal layer and the insulating layer to selectively remove the top metal layer with respect to the underlying insulating layer.
20. A process as in claim 19 wherein the non-reactive gas is Ar, He, Ne, Kr, N 2 , or Xe, or any combination thereof.
21. A process as in claim 19 wherein the oxygen-containing gas is O, O 2 , N 2 O, NO, air, CO, or any combination thereof.
22. A process as in claim 19 wherein the mixture is 99.9% Ar and 0.1% O 2 .
23. A process as in claim 19 wherein the mixture of a non-reactive gas and an oxygen-containing gas is introduced through a first flow controller and a non-reactive gas is introduced through a second flow controller.
24. A process as in claim 19 wherein the first flow controller provides 80 sccm of argon and 0.08 sccm of O 2 and the second flow controller provides 270 sccm of argon.
25. A process as in claim 19 wherein the non-reactive gas is in the range of 10 to 350 sccm and the oxygen-containing gas is in the range of 0.02 to 0.15 sccm.
26. A process as in claim 19 wherein the oxygen-containing gas is introduced into the process from the sputtering of a solid source of an oxygen-containing solid.
27. A process as in claim 26 wherein the solid source comprises alumina or quartz.
28. A process as in claim 19 wherein the oxygen-containing gas is introduced from controlled leakage.
29. A process as in claim 19 further comprising the step of forming a bottom metal layer under the insulating layer.
30. A process as in claim 19 wherein a plasma is formed with the non-reactive gas.
31. A process as in claim 19 wherein the insulating layer comprises aluminum oxide, magnesium oxide, or any insulating oxide.
32. A process as in claim 19 wherein the top metal layer comprises a magnetic layer, part of an MRAM stack structure, or one or more layers of NiFe, CoFe, CoNiFe, and CoFeB.
33. A process for fabricating a device comprising:
(a) providing a substrate;
(b) forming an insulating layer over the substrate;
(c) forming a top metal layer over the insulating layer; and
(d) applying a bias to the substrate with bias power between the sputter threshold of the top metal layer and the insulating layer to selectively remove the top metal layer with respect to the underlying insulating layer.
34. A process as in claim 33 wherein the insulating layer comprises an insulating oxide.
35. A process for fabricating a device comprising:
(a) providing a substrate;
(b) forming an insulating layer over the substrate;
(c) forming a top metal layer over the insulating layer; and
(d) applying a physical sputter etch process using a mixture of a non-reactive gas and <1 of an oxygen-containing gas and a bias to the substrate with bias power between the sputter threshold of the top metal layer and the insulating layer to selectively remove the top metal layer with respect to the underlying insulating layer.
36. A process for fabricating a magnetic junction memory device comprising:
(a) receiving a substrate in a process chamber;
(b) forming an insulating layer over the substrate;
(c) forming a top metal layer over the insulating layer; and
(d) introducing a non-reactive gas to the process chamber;
(e) applying a bias to the substrate with bias power between the sputter threshold of the top metal layer and the insulating layer to selectively remove the top metal layer with respect to the underlying insulating layer.
37. A process as in claim 36 wherein the non-reactive gas includes one or more of Ar, He, Ne, Kr, N 2 , and Xe.
38. A process as in claim 36 further comprising the step of forming a bottom metal layer between the substrate and the insulating layer.
39. A process as in claim 36 wherein a plasma is formed with the non-reactive gas.
40. A process as in claim 36 wherein the insulating layer comprises aluminum oxide, magnesium oxide, or any insulating oxide.
41. A process as in claim 36 wherein the top metal layer comprises a magnetic layer, part of an MRAM stack structure, or one or more layers of NiFe, CoFe, CoNiFe, and CoFeB.
42. A process for fabricating a magnetic junction memory device comprising:
(a) receiving a substrate in a process chamber;
(b) forming an insulating layer over the substrate;
(c) forming a top metal layer over the insulating layer;
(d) introducing a non-reactive gas to the process chamber;
(e) introducing an oxygen-containing gas to the process chamber by sputtering one or both of alumina and quartz so that a mixture of non-reactive gas and <1% oxygen-containing gas is formed in the process chamber; and
(d) applying a physical sputter etch process to remove the top metal layer with respect to the underlying insulating layer.
43. A process as in claim 42 wherein the non-reactive gas includes one or more of Ar, He, Ne, Kr, N 2 , and Xe.
44. A process as in claim 42 wherein the oxygen-containing gas is O, O 2 , N 2 O, NO, air, CO, or any combination thereof.
45. A process as in claim 42 wherein the mixture is 99.9% Ar and 0.1% O 2 .
46. A process as in claim 42 further comprising the step of forming a bottom metal layer under the insulating layer.
47. A process as in claim 42 wherein a plasma is formed with the non-reactive gas.
48. A process as in claim 42 wherein the insulating layer comprises aluminum oxide, magnesium oxide, or any insulating oxide.
49. A process as in claim 42 wherein the top metal layer comprises a magnetic layer, part of an MRAM stack structure, or one or more layers of NiFe, CoFe, CoNiFe, and CoFeB.
50. A process for fabricating a magnetic junction memory device comprising:
(a) receiving a substrate in a process chamber;
(b) forming an insulating layer over the substrate;
(c) forming a top metal layer over the insulating layer; and
(d) introducing a mixture of a non-reactive gas and < 1 % of an oxygen-containing gas to the process chamber;
(e) applying a bias to the substrate with bias power between the sputter threshold of the top metal layer and the insulating layer to selectively remove the top metal layer with respect to the underlying insulating layer.
51. A process as in claim 50 wherein the non-reactive gas is one or more of Ar, He, Ne, Kr, N 2 , and Xe.
52. A process as in claim 50 wherein the oxygen-containing gas is O, O 2 , N 2 O, NO, air, CO, or any combination thereof.
53. A process as in claim 50 wherein the mixture is 99.9% Ar and 0.1% O 2 .
54. A process as in claim 50 wherein introducing the mixture includes introducing a first portion of the non-reactive gas mixed with the oxygen-containing gas through a first flow controller and introducing a second portion of non-reactive gas through a second flow controller.
55. A process as in claim 50 wherein the first flow controller provides 80 sccm of argon and 0.08 sccm of O 2 and the second flow controller provides 270 sccm of argon.
56. A process as in claim 50 wherein the non-reactive gas is in the range of 10 to 350 sccm and the oxygen-containing gas is in the range of 0.02 to 0.15 sccm.
57. A process as in claim 50 wherein the oxygen-containing gas is introduced into the process from the sputtering of a solid source of an oxygen-containing solid.
58. A process as in claim 57 wherein the solid source comprises alumina or quartz.
59. A process as in claim 57 wherein the solid source is a consumable component of the process chamber.
60. A process as in claim 50 wherein the oxygen-containing gas is introduced from controlled leakage into the process chamber.
61. A process as in claim 50 further comprising the step of forming a bottom metal layer under the insulating layer.
62. A process as in claim 50 wherein a plasma is formed with the non-reactive gas.
63. A process as in claim 50 wherein the insulating layer comprises aluminum oxide, magnesium oxide, or any insulating oxide.
64. A process as in claim 50 wherein the top metal layer comprises a magnetic layer, part of an MRAM stack structure, or one or more layers of NiFe, CoFe, CoNiFe, and CoFeB.