MAGNETIC SENSOR HAVING AN EXTENDED PINNED LAYER AND SHAPE ENHANCED BIAS STRUCTURE

• US 20140168824A1
• Filed: 12/19/2012
• Published: 06/19/2014
• Est. Priority Date: 12/19/2012
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: HGST Netherlands B.V. (Western Digital Corporation)
• Inventors: Ju, Kochan, Le, Quang, Liao, Simon H., Liu, Guangli
• Granted Patent: US 8,842,395 B2
• Time in Patent Office: Days
• US Class Current: 360/324.11
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G01R 33/098 comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
• CPC Class Codes: G11B 5/3906 Details related to the use of magnetic thin film layers or to their effects
• CPC Class Codes: G11B 5/3932 Magnetic biasing films
• CPC Class Codes: G11B 5/398 Specially shaped layers
• CPC Class Codes: H01F 10/3268 the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn

Abstract

A magnetic read sensor having an extended pinned layer structure and also having an extended free layer structure. The extended pinned layer structure and extended free layer structure both extend beyond the strip height of the free layer of the sensor to provide improved pinning strength as well as improved free layer biasing reliability and bias field strength.

Claims

1. A magnetic read sensor, comprising:

a sensor stack comprising a magnetic pinned layer structure, a magnetic free layer structure and a non-magnetic layer disposed between the magnetic pinned layer structure and magnetic free layer structure, the sensor stack having first and second sides, the free layer having a back edge terminating at a first stripe height as measured from an air bearing surface, and the pinned layer structure having an extended portion that extends beyond the stripe first height to a second stripe height; and

first and second hard bias structures separated from the first and second sides of the sensor stack by first and second insulation layers the hard bias structures having a back edge that defines a hard bias stripe height that is longer than the first stripe height, but shorter than the second stripe height.

2. The magnetic read sensor as in claim 1 wherein the extended portion of the pinned layer structure has an edge that includes a tapered portion.

3. The magnetic read sensor as in claim 2 wherein each of the hard bias structures has a back edge that conforms to the edge of the extended portion of the pinned layer.

4. The magnetic read sensor as in claim 1 wherein the extended portion of the pinned layer structure has an edge that includes a tapered portion that defines an angle of 30-60 degrees relative to a plane that is parallel with the air bearing surface.

5. The magnetic read sensor as in claim 4 wherein each of the hard bias structures has a back edge that conforms to the edge of the extended portion of the pinned layer.

6. The magnetic read sensor as in claim 1 wherein the extended portion of the pinned layer structure has an edge that includes a tapered portion that defines an angle of about 45 degrees relative to a plane that is parallel with the air bearing surface.

7. The magnetic read sensor as in claim 6 wherein each of the hard bias structures has a back edge that conforms to the edge of the extended portion of the pinned layer.

8. The magnetic read sensor as in claim 1 wherein the extended portion of the pinned layer structure has an edge that includes a laterally extending portion that is substantially parallel with the air bearing surface and a tapered portion that is tapered relative to a plane that is parallel with the air bearing surface.

9. The magnetic read sensor as in claim 8 wherein each of the hard bias structures has a back edge that conforms to the edge of the extended portion of the pinned layer.

10. The magnetic read sensor as in claim 1 wherein the extended portion of the pinned layer structure has an edge that includes a laterally extending portion that is substantially parallel with the air bearing surface and a tapered portion that defines an angle of 30-60 degrees relative to a plane that is parallel with the air bearing surface.

11. The magnetic read sensor as in claim 10 wherein each of the hard bias structures has a back edge that conforms to the edge of the extended portion of the pinned layer.

12. The magnetic read sensor as in claim 1 wherein the extended portion of the pinned layer structure has an edge that includes a laterally extending portion that is substantially parallel with the air bearing surface and a tapered portion that defines an angle of about 45 degrees relative to a plane that is parallel with the air bearing surface.

13. The magnetic read sensor as in claim 13 wherein each of the hard bias structures has a back edge that conforms to the edge of the extended portion of the pinned layer.

14. A method for manufacturing a magnetic read sensor, the method comprising:

depositing a series of sensor layers, the series of sensor layers including a pinned layer structure, a non-magnetic layer formed over the pinned layer structure and a free layer structure over the non-magnetic layer;

forming a first mask structure over the series of sensor layers, the first mask structure being configured to define a stripe height of the free layer structure;

performing a first ion milling to remove portions of the free layer structure that are not protected by the first mask structure thereby defining a free layer stripe height, the first ion milling being terminated before removing the pinned layer structure;

forming a second mask structure, over the series of sensor layers, the second mask structure being configured to define a sensor track width and having a portion extending beyond the free layer stripe height that is configured to define an extended pinned layer shape; and

performing a second ion milling, the second ion milling being performed sufficiently to remove portions of the free layer structure, non-magnetic layer and pinned layer structure that are not protected by the second mask structure.

15. The method as in claim 15, further comprising after performing the second ion milling, depositing a thin, non-magnetic, electrically insulating layer and depositing a magnetic bias material over the thin, non-magnetic, electrically insulating material.

16. The method as in claim 15, further comprising after performing the second ion milling, depositing a thin, non-magnetic, electrically insulating layer, depositing a magnetic bias material over the thin, non-magnetic, electrically insulating material, and depositing a hard bias capping layer over the magnetic bias material.

18. The method as in claim 15 wherein the portion of the second mask structure extending beyond the sensor stripe height is configured with an edge that is neither perpendicular to nor parallel with an intended air bearing surface plane.

19. The method as in claim 15 wherein the portion of the second mask structure extending beyond the sensor stripe height is configured with an edge that defines an angle of 30-60 degrees relative to a plane that is parallel with an intended air bearing surface plane.

17. The method as in claim 17, further comprising, after depositing the hard bias capping layer:

performing a chemical mechanical polishing;

forming a third mask structure configured to cover a sensor area, extended pinned layer area and a hard bias area and leaving a kerf region uncovered; and

performing a third ion milling to remove portions of the series of sensor layers that are not protected by the third mask structure.

20. The method as in claim 20 wherein the portion of the second mask structure extending beyond the sensor stripe height further includes a portion that extends laterally outward having an edge that is substantially parallel with the intended air bearing surface plane.