Dual write heater for slider surface topography control in double perpendicular magnetic recording (PMR) writers

• US 10,360,935 B1
• Filed: 05/22/2018
• Issued: 07/23/2019
• Est. Priority Date: 05/22/2018
• Status: Active Grant

• Current Assignee: Headway Technologies Incorporated (TDK Corporation)
• Original Assignee: Headway Technologies Incorporated (TDK Corporation)
• Inventors: Liu, Kowang, Ngan, Siu Yin, Zeng, Qing Hua, Cha, Ellis
• Primary Examiner(s): Evans, Jefferson A
• Application Number:
  US15/986,261
• Time in Patent Office: 427 Days
• Field of Search: 36012303, 36012305, 36012306, 3601231, 36012311, 36012504, 36012505, 3601253, 36012531, 3602947, 3602371
• CPC Class Codes: G11B 2005/0021 Thermally assisted recording using an auxiliary energy source for heating the recording layer locally to assist the magnetization reversal
• CPC Class Codes: G11B 5/1278 specially adapted for magnetisations perpendicular to the surface of the record carrier
• CPC Class Codes: G11B 5/17 Construction or disposition of windings
• CPC Class Codes: G11B 5/3133 including layers not usually being a part of the electromagnetic transducer structure and providing additional features, e.g. for improving heat radiation, reduction of power dissipation, adaptations for measurement or indication of gap depth or other properties of the structure G11B5/3106 takes precedence
• CPC Class Codes: G11B 5/314 where the layers are extra layers normally not provided in the transducing structure, e.g. optical layers G11B5/3196 takes precedence
• CPC Class Codes: G11B 5/3166 Testing or indicating in relation thereto, e.g. before the fabrication is completed
• CPC Class Codes: G11B 5/3196 of thin magnetic films, e.g. functional testing of the transducing properties G11B5/455 takes precedence
• CPC Class Codes: G11B 5/607 using thermal means
• CPC Class Codes: G11B 5/6082 Design of the air bearing surface

Abstract

A dual perpendicular magnetic recording writer is disclosed wherein first and second dynamic fly height (DFH) heaters WDFH1 and WDFH2, are formed in first and second writers, respectively, on a slider in a head gimbal assembly. In one embodiment, WDFH1 and WDFH2 have front sides that are recessed behind first and second back gap connections (BGC), respectively, and join together at their respective backsides behind the interconnect which connects a bucking coil and driving coil each symmetrically disposed about a center plane separating the two writers. In another embodiment with a separate bucking coil in each writer, WDFH1 and WDFH2 are formed behind separate interconnects. Magnetic spacing loss is reduced compared with a single DFH heater spread across both writers. Close point at touchdown in a cross-track direction and the size of the touchdown area are controlled by applying a WDFH1:WDFH2 power ratio from 100:0 to 0:100.

Claims

1. A dual perpendicular magnetic recording (PMR) writer, comprising:

(a) a first main pole layer in a first PMR writer having a first main pole tip with a leading side and trailing side at an air bearing surface (ABS), and bisected by a first plane that is at a first cross-track position and is orthogonal to the ABS, and wherein the first PMR writer is formed on a slider;

(b) a second main pole layer in a second PMR writer formed on the slider, and having a second main pole tip with a leading side and trailing side at the ABS, and bisected by a second plane that is orthogonal to the ABS, wherein the first and second planes are equidistant from a center plane that separates the first and second PMR writers;

(c) a bucking coil (BC) that is formed below the first and second main pole layers, and is recessed from the ABS, and wherein the bucking coil is connected to a driving coil by an interconnect;

(d) the driving coil (DC) that is formed above the first and second main pole layers, is recessed from the ABS, and contacts a top surface of the interconnect;

(e) a first dynamic fly height (DFH) heater coil (WDFH1) formed in the first PMR writer, and between the bucking coil and the driving coil; and

(f) a second DFH heater coil (WDFH2) formed in the second PMR writer, and between the bucking coil and the driving coil, wherein WDFH1 and WDFH2 are configured to adjust a close point proximate to the first plane when the first PMR writer is selected for a write process, and to adjust the close point proximate to the second plane when the second PMR writer is selected for a write process.

2. The dual PMR writer of claim 1 wherein the bucking coil has a BC first outer portion in the first PMR writer, a BC second outer portion in the second PMR writer, and a BC center portion at the center plane, and wherein the interconnect adjoins a backend of the BC center portion.

3. The dual PMR writer of claim 2 wherein the driving coil has a DC first outer portion in the first PMR writer, a DC second outer portion in the second PMR writer, and a DC center portion at the center plane, and wherein the interconnect adjoins a backend of the DC center portion.

4. The dual PMR writer of claim 3 wherein the write process with the first PMR writer comprises sending a write current through the DC first outer portion, DC center portion, interconnect, BC center portion, and BC first outer portion, and activating at least WDFH1 by sending a current from a WDFH1+ heater pad through WDFH1 to a ground (H/G) pad at the center plane.

5. The dual PMR writer of claim 4 wherein WDFH1 has an outer portion connected to the WDFH1+ heater pad, a front side that is recessed behind a first back gap connection (BGC) in the first PMR writer, and an inner portion having a serpentine shape that extends from the front side to a first backside behind the interconnect, and wherein the first backside adjoins a second backside of WDFH2 at a backend at the center plane.

6. The dual PMR writer of claim 3 wherein the write process with the second PMR writer comprises sending a write current through the DC second outer portion, DC center portion, interconnect, BC center portion, and BC second outer portion, and activating at least WDFH2 by sending a current from a WDFH2+ heater pad through WDFH2 to a H/G pad.

7. The dual PMR writer of claim 6 wherein WDFH2 has an outer portion connected to the WDFH2+ heater pad, a front side that is recessed behind a second BGC in the second PMR writer, and an inner side having a serpentine shape that extends from the WDFH2 front side to a second backside behind the interconnect, and wherein the second backside adjoins a first backside of WDFH1 at a backend at the center plane.

8. The dual PMR writer of claim 1 wherein WDFH1 and WDFH2 have a cross-track footprint less than a cross-track footprint of the bucking coil.

9. The dual PMR writer of claim 1 wherein WDFH1 and WDFH2 are made of Cu, W, or Ta and have a thickness from about 400 Angstroms to 1000 Angstroms.

10. The dual PMR writer of claim 1 wherein a first power is applied to WDFH1 and a second power is applied to WDFH2 to give a WDFH1:

WDFH2 power ratio that is from 100;

0 to 0;

100 in order to adjust a close point of a touchdown area at the ABS and along a cross-track direction that is toward the first plane when the first PMR writer is selected for the write process, or toward the second plane when the second PMR writer is selected for the write process.

11. The dual PMR writer of claim 10 wherein the WDFH1:

WDFH2 power ratio further adjusts a size of the touchdown area.

12. A head gimbal assembly (HGA) comprising a suspension on which the slider of claim 1 is formed, and wherein the suspension comprises a load beam with one end connected to a flexure, and a base plate connected to the other end of the load beam.

13. A magnetic recording apparatus, comprising:

(a) the HGA according to claim 12;

(b) a magnetic recording medium positioned opposite to the slider;

(c) a spindle motor that rotates and drives the magnetic recording medium; and

(d) a device that supports the slider, and that positions the slider relative to the magnetic recording medium.

14. A dual perpendicular magnetic recording (PMR) writer, comprising:

(a) a first main pole layer in a first PMR writer having a first main pole tip with a leading side and trailing side at an air bearing surface (ABS), and bisected by a first plane that is at a first cross-track position and is orthogonal to the ABS, and wherein the first PMR writer is formed on a slider;

(b) a second main pole layer in a second PMR writer formed on the slider, and having a second main pole tip with a leading side and trailing side at the ABS, and bisected by a second plane that is orthogonal to the ABS, wherein the first and second planes are equidistant from a center plane that separates the first and second PMR writers;

(c) a first bucking coil that is formed below the first main pole layer in the first PMR writer, and is connected to a first driving coil or a common driving coil with a first interconnect;

(d) a second bucking coil formed below the second main pole layer in the second PMR writer; and

is connected to a second driving coil or the common driving coil with a second interconnect;

(e) a first dynamic fly height (DFH) heater coil (WDFH1) formed above the first bucking coil in the first PMR writer; and

(f) a second DFH heater coil (WDFH2) formed above the second bucking coil in the second PMR writer, wherein WDFH1 and WDFH2 are configured to adjust a close point proximate to the first plane when the first PMR writer is selected for a write process, and to adjust the close point proximate to the second plane when the second PMR writer is selected for a write process.

15. The dual PMR writer of claim 14 wherein a write process with the first PMR writer comprises sending a write current through the first bucking coil, first interconnect, and through the first driving coil or common driving coil, and activating WDFH1 by sending a current from a WDFH1+ heater pad through WDFH1 to a ground (H/G) pad at the center plane.

16. The dual PMR writer of claim 15 wherein WDFH1 has an outer portion connected to the WDFH1+ heater pad, a front side that is recessed behind the first interconnect, and a center portion having a serpentine shape that extends from the WDFH1 front side to a first backside, and wherein the first backside adjoins a second backside of WDFH2 at the center plane.

17. The dual PMR writer of claim 14 wherein a write process with the second PMR writer comprises sending a write current through the second bucking coil, second interconnect, and through the second driving coil or common driving coil, and activating WDFH2 by sending a current from a WDFH2+ heater pad through WDFH2 to a H/G pad at the center plane.

18. The dual PMR writer of claim 17 wherein WDFH2 has an outer portion connected to the WDFH2+ heater pad, a front side that is recessed behind the second interconnect, and a center portion having a serpentine shape that extends from the WDFH2 front side to a second backside, and wherein the second backside adjoins a first backside of WDFH1 at the center plane.

19. The dual PMR writer of claim 14 wherein WDFH1 and WDFH2 are made of Cu, W, or Ta, and have a thickness from about 400 Angstroms to 1000 Angstroms.

20. The dual PMR writer of claim 14 wherein a first power is applied to WDFH1 and a second power is applied to WDFH2 to give a WDFH1:

WDFH2 power ratio that is from 100;

0 to 0;

100 in order to adjust a close point of a touchdown area at the ABS and along a cross-track direction that is toward the first plane when the first PMR writer is selected for the write process, or toward the second plane when the second PMR writer is selected for the write process.

21. The dual PMR writer of claim 20 wherein the WDFH1:

WDFH2 power ratio also adjusts a size of the touchdown area.

22. A head gimbal assembly (HGA) comprising a suspension on which the slider of claim 14 is formed, and wherein the suspension comprises a load beam with one end connected to a flexure, and a base plate connected to the other end of the load beam.

23. A magnetic recording apparatus, comprising:

(a) the HGA according to claim 22;

(b) a magnetic recording medium positioned opposite to the slider;

(c) a spindle motor that rotates and drives the magnetic recording medium; and

(d) a device that supports the slider, and that positions the slider relative to the magnetic recording medium.

24. A method of adjusting a write gap (WG) protrusion close point position during a write process with a first perpendicular magnetic recording (PMR) writer, or during a write process with a second PMR writer in a dual PMR writer;

comprising;

(a) providing a first main pole in the first PMR writer with a first main pole tip which is bisected by a first plane that is orthogonal to an air bearing surface (ABS);

(b) providing a second main pole in the second PMR writer with a second main pole tip that is bisected by a second plane that is orthogonal to the ABS, and wherein the first and second planes are equidistant from a center plane that separates the first and second PMR writers on a slider in a head gimbal assembly (HGA);

(c) providing a first circuit comprised of a bucking coil portion, a driving coil portion, and an interconnect between the BC and DC portions in the first circuit through which a write current is sent to activate the first PMR writer for a write process;

(d) providing a second circuit comprised of a bucking coil portion, a driving coil portion, and the interconnect between the BC and DC portions in the second circuit through which a write current is sent to activate the second PMR writer for a write process;

(e) forming a first dynamic fly height (DFH) heater coil (WDFH1) between the BC and DC portions in the first circuit, and a second DFH heater coil (WDFH2) between the BC and DC portions in the second circuit so that at least WDFH1 is activated during a write process with the first PMR writer, and at least WDFH2 is activated during a write process with the second PMR writer; and

(f) applying a first power to WDFH1 and a second power to WDFH2 to give a WDFH1;

WDFH2 power ratio from 100;

0 to 0;

100 that adjusts the close point position toward the first plane during a write process with the first PMR writer, or toward the second plane during a write process with the second PMR writer.

25. The method of claim 24 wherein the BC portion in the first PMR writer comprises a BC first outer portion, and a BC center portion that is connected to the interconnect at the center plane, and the BC portion in the second PMR writer comprises the BC center portion and a BC second outer portion, and wherein the DC portion in the first PMR writer comprises a DC first outer portion, and a DC center portion connected to the interconnect, and the DC portion in the second PMR writer comprises a DC second outer portion and the DC center portion.

26. The method of claim 25 wherein the first circuit comprises the BC first outer portion, BC center portion, interconnect, DC center portion, and DC first outer portion, and wherein the second circuit comprises the BC second outer portion, BC center portion, interconnect, DC center portion, and DC second outer portion.

27. The method of claim 24 wherein the first power is applied by sending a current from a WDFH1+ heater pad through WDFH1 to a ground (H/G) pad, and wherein the second power is applied by sending a current from a WDFH2+ heater pad through WDFH2 to the H/G pad.

28. The method of claim 27 wherein WDFH1 has an outer portion connected to the WDFH1+ heater pad, a front side that is recessed behind a first back gap connection (BGC) in the first PMR writer, and an inner portion having a serpentine shape that extends from the WDFH1 front side to a first backside behind the interconnect, and wherein the first backside adjoins a second backside of WDFH2 at a backend connected to the H/G pad at the center plane.

29. The method of claim 27 wherein WDFH2 has an outer portion connected to the WDFH2+ heater pad, a front side that is recessed behind a second BGC in the second PMR writer, and an inner side having a serpentine shape that extends from the WDFH2 front side to a second backside behind the interconnect, and wherein the second backside adjoins a first backside of WDFH1 at a backend connected to the H/G pad at the center plane.

30. The method of claim 24 wherein the WDFH1:

WDFH2 power ratio also adjusts a size of a touchdown area of the dual PMR writer during the write process with the first PMR writer or with the second PMR writer.