Method of fabricating a tunneling magnetoresistive (TMR) reader

1. A method of fabricating a tunneling magnetoresistance (TMR) reader, the method comprising:

providing a TMR structure comprising at least one ferromagnetic layer and at least one nonmagnetic insulating layer;

performing a first thermal annealing process on the TMR structure;

performing a reader pattern definition process on the TMR structure to obtain a patterned TMR reader; and

performing a second thermal annealing process on the patterned TMR reader,

wherein the at least one ferromagnetic layer comprises a pinning layer, a pinned layer, and a free layer; and the at least one nonmagnetic insulating layer comprises a tunneling barrier layer disposed between the pinned layer and the free layer.

2. The method of claim 1 , wherein the reader pattern definition process comprises an ion milling operation.

3. The method of claim 1 , wherein the TMR structure further comprises a capping layer deposited over the free layer, further wherein the first thermal annealing process is performed after depositing the capping layer.

4. The method of claim 1 , wherein the first thermal annealing process is performed while applying an external magnetic field to the TMR structure, thereby inducing a pinning field in the pinning layer and defining a direction of the pinning field.

5. The method of claim 1 , further comprising the step of disposing a spacing layer over the patterned TMR reader and a hard bias layer over the insulating layer.

6. The method of claim 5 , wherein the spacing layer comprises an atomic layer deposition (ALD) aluminum oxide.

7. The method of claim 5 , wherein the hard bias layer comprises a composition of cobalt and platinum.

8. The method of claim 5 , wherein the second thermal annealing process enhances an effective hard bias field inside the patterned TMR reader.

9. The method of claim 1 , wherein a second annealing temperature for the second thermal annealing process is equal to or lower than a first annealing temperature for the first thermal annealing process.

10. The method of claim 9 , wherein the first annealing temperature is in a range of between about 250 and 300° C., and the second annealing temperature is in a range of between about 220 and 270° C.

11. The method of claim 1 , wherein a second soaking time for the second thermal annealing process is equal to or lower than a first soaking time for the first thermal annealing process.

12. The method of claim 11 , wherein the first soaking time is in a range of between about 2 and 5 hours, and the second soaking time is in a range of between about 10 minutes and 1 hour.

13. The method of claim 1 further comprising performing a writer pattern definition process to form a patterned writer associated with the patterned TMR reader.

14. The method of claim 13 further comprising performing a third thermal annealing process after forming the patterned writer.

15. The method of claim 14 , wherein the third thermal annealing process improves an overwrite capability of the patterned writer.

16. The method of claim 14 , wherein a third annealing temperature for the third thermal annealing process is equal to or lower than a first annealing temperature for the first thermal annealing process.

17. The method of claim 16 , wherein the first annealing temperature is in a range of between about 250 and 300° C., and the third annealing temperature is in a range of between about 190 and 240° C.

18. The method of claim 14 , wherein a third soaking time for the third thermal annealing process is equal to or lower than a first soaking time for the first thermal annealing process.

19. The method of claim 18 , wherein the first soaking time is in a range of between about 2 and 5 hours, and the third soaking time is in a range of between about 10 minutes and 2 hours.