Method of making a magnetoresistive reader structure
View Patent ↗A method of making a magnetoresistive sensor includes defining a track width of a magnetoresistive element stack of the sensor. Further, processes of the method enable depositing of hard magnetic bias material on each side of the stack. These processes may permit both milling of excess depositions of the material outside of regions where the hard magnetic bias material is desired via use of a photoresist and making the material have a planar surface via chemical mechanical polishing, which also removes the material on top of the stack. The method includes removing excess material outside of the photoresist, wherein the excess material includes part of the hard bias layer, while a portion of the hard bias layer remains directly above the MR sensor stack.
1. A method of forming a magnetoresistive (MR) read sensor, comprising:
providing a MR sensor stack within a dielectric;
removing a portion of the MR sensor stack and the dielectric to define a track width of the MR read sensor;
depositing a hard bias layer on both sides of the MR sensor stack within voids defined by the portion removed;
applying a photoresist above the hard bias layer and over the MR sensor stack; and
removing excess material outside of the photoresist, wherein the excess material includes part of the hard bias layer, while a portion of the hard bias layer remains directly above the MR sensor stack.
2. The method of claim 1 , further comprising chemical mechanical polishing the hard bias layer after removing the excess material.
3. The method of claim 1 , further comprising:
depositing a hard mask layer above the MR sensor stack;
patterning by photo exposure a film above the hard mask layer; and
removing the hard mask layer where the film is patterned to thereby enable removing the portion unprotected by the hard mask layer.
4. The method of claim 3 , wherein the hard mask layer comprises diamond like carbon.
5. The method of claim 3 , wherein removing the hard mask layer where the film is patterned comprises reactive ion etching.
6. The method of claim 3 , further comprising reactive ion etching the hard mask layer to remove all of the hard mask layer after chemical mechanical polishing of the hard bias layer.
7. The method of claim 3 , further comprising lifting off the film prior to depositing the hard bias layer.
8. The method of claim 1 , wherein removing the excess material comprises ion milling.
9. The method of claim 1 , wherein removing the portion comprises ion milling.
10. The method of claim 1 , wherein the photoresist is patterned to be inside of a dimension corresponding to outer boundaries of the portion removed.
11. The method of claim 10 , wherein the photoresist is patterned to be about 250 nanometers inside of the dimension.
12. A method of forming a magnetoresistive (MR) read sensor, comprising:
providing a MR sensor stack within a dielectric;
removing a portion of the MR sensor stack and the dielectric to define a track width of the MR read sensor;
depositing a hard bias layer on both sides of the MR sensor stack within voids defined by the portion removed;
applying a photoresist above the hard bias layer and over the MR sensor stack;
removing excess material outside of the photoresist, wherein the excess material includes part of the hard bias layer; and
depositing an insulation layer on a hard mask above the MR sensor stack and on both sides of the MR sensor stack, wherein the hard bias layer is deposited on top of the insulation layer and fills the voids and the excess material removed includes part of the insulation layer.
13. The method of claim 12 , further comprising chemical mechanical polishing the hard bias layer after removing the excess material.
14. The method of claim 12 , further comprising:
depositing a hard mask layer above the MR sensor stack;
patterning by photo exposure a film above the hard mask layer; and
removing the hard mask layer where the film is patterned to thereby enable removing the portion unprotected by the hard mask layer.
15. The method of claim 14 , wherein the hard mask layer comprises diamond like carbon.
16. The method of claim 14 , wherein removing the hard mask layer where the film is patterned comprises reactive ion etching.
17. The method of claim 14 , further comprising reactive ion etching the hard mask layer to remove all of the hard mask layer after chemical mechanical polishing of the hard bias layer.
18. The method of claim 14 , further comprising lifting off the film prior to depositing the hard bias layer.
19. The method of claim 12 , wherein removing the excess material comprises ion milling.
20. The method of claim 12 , wherein removing the portion comprises ion milling.
21. The method of claim 12 , wherein the photoresist is patterned to be inside of a dimension corresponding to outer boundaries of the portion removed.
22. The method of claim 21 , wherein the photoresist is patterned to be about 250 nanometers inside of the dimension.