Intergrated thin film subgap subpole structure for arbitrary gap pattern magnetic recording heads and method of making the same

• US 20050254170A1
• Filed: 05/03/2005
• Published: 11/17/2005
• Est. Priority Date: 05/04/2004
• Status: Active Grant

• Current Assignee: Advanced Research Corporation
• Original Assignee: Advanced Research Corporation
• Inventors: Dugas, Matthew P., Schwarz, Theodore A.
• Granted Patent: US 7,450,341 B2
• Time in Patent Office: Days
• US Class Current: 360/119.110
• CPC Class Codes: G11B 5/3103 Structure or manufacture of integrated heads or heads mechanically assembled and electrically connected to a support or housing
• CPC Class Codes: G11B 5/3163 Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
• CPC Class Codes: G11B 5/3173 Batch fabrication, i.e. producing a plurality of head structures in one batch
• CPC Class Codes: G11B 5/3179 the films being mainly disposed in parallel planes
• CPC Class Codes: G11B 5/3183 intersecting the gap plane, e.g. "horizontal head structure"
• CPC Class Codes: G11B 5/584 for track following on tapes

Abstract

An arbitrary gap thin film magnetic recording head is fabricated by forming a substrate based on traditional vertical planar thin film head wafer technology which is designed to produce an integrated subgap and subpole substrate structure. The wafer is then processed into row bars to reveal, in a plane parallel to the transducing direction of the medium, the subgap and subpoles at the surface of the row bar and to bring the structure to a certain coil depth or gap depth. A flat or cylindrical contour may be utilized. This thin film subgap row bar is taken through a film deposition or growth process that deposits the magnetic film on a plane perpendicular to the wafer plane, horizontal planar processing, forming a surface film recording head where an arbitrary gap structure can be made in-between the subpoles and generally directly on top of the subgap. The surface thin film is deposited and patterned on the tape bearing surface of the head to optimize various element configurations, gap patterns and head-to-tape medium contact. An arbitrary gap thin film magnetic recording head is manufactured using two major thin film processing planes, one orthogonal to the other, the first major plane is wafer level and the second major plane is sub-wafer level and perpendicular to the first. The first major plane of processing defines the magnetically active substrate including coils, subgap and subpole members. The second major plane of processing defines the surface film which transmits the flux from the subpoles to the gap features contained in the surface film. This resulting structure is a recording head that is wired to the servo system electronics and will format the tape with the arbitrary gap pattern.

Claims

1. An integrated surface film magnetic recording head for writing and reading arbitrary gap patterns on media and having at least one recording element, comprising:

a) a pair of magnetically permeable thin film subpole members, separated by a substantially low permeability subgap member, an electrically conductive coil structure embedded in part within the subgap structure and in part in-between the pair of subpoles, the gap member and pole members forming part of a magnetic circuit; and

b) a highly permeable magnetic surface film layer which spans from at least one subpole to another subpole and which includes one or more arbitrary recording gap patterns.

2. The magnetic recording head of claim 1, further comprising:

a plurality of recording elements.

3. The magnetic recording head of claim 2, further comprising:

a plurality of recording elements which are substantially magnetically isolated and electrically independent of one another, each one having a unique coil.

4. The magnetic recording head of claim 2, further comprising:

a plurality of recording elements which share a common coil.

5. The magnetic recording head of claim 1, where two or more heads are used in combination to form one set of servo marks on a recording medium.

7. The magnetic recording head of claim 1, wherein the surface thin film layer is located only over a portion of the recording head primarily between the subpoles.

8. The magnetic recording head of claim 1, wherein the thin film layer has been selectively removed in portions so as to magnetically isolate each of the magnetically permeable surface films elements but has not been removed in selected areas over the head so as to form a quasi-contiguous tape bearing surface.

9. The magnetic recording head of claim 1, wherein the writing gaps have curved or slanted termination features that prevent the writing of stray marks on the medium outside the gaps.

10. The magnetic recording head of claim 1, wherein the surface film is structured to focus the flux from the subpoles across the surface film lying on top of the non-permeable subgap region so as to maximize the flux delivered to the gap.

11. The magnetic head of claim 1, wherein the pattern is a timing based servo pattern.

12. The magnetic head of claim 1, wherein the pattern is an amplitude based servo pattern.

13. The magnetic head of claim 1, wherein the pattern is a combination of a timing based and an amplitude based servo pattern.

14. The recording head of claim 1, where the coil structure is of a single layer coil.

15. The recording head of claim 1, where the coil structure is a multi-layer coil.

16. The recording head of claim 1, where there is no apex point between the first subpole and second subpole and where the distance to the first turn of the coil from the subgap surface is a primary control parameter.

17. The recording head of claim 1, where there is an apex point between the first subpole and second subpole and the distance from the subgap surface to the apex point is a primary control parameter.

6. An integrated thin film magnetic recording head for writing and reading arbitrary gap patterns on media and having two major processing planes, the second major processing plane being orthogonal to the first major processing plane, and comprising:

upon the first major processing plane, a pair of magnetically permeable thin film subpole members, separated by a substantially low permeability subgap member, the subgap member and subpole members forming part of a magnetic circuit;

an electrically conductive coil structure positioned below the subgap surface and embedded in part in-between the pair of subpoles, and upon the second major processing plane the formation on top thereof of a highly permeable magnetic surface film layer which contains arbitrary recording gap features.

18. A method of making thin film subgap, subpole substrate for an arbitrary surface film magnetic recording head, comprising:

A) A first major plane of processing which comprises

1) depositing and forming a first subpole pole layer on wafer substrate,

2) depositing and forming a coil insulating layer and partial subgap layer,

3) depositing and forming a coil layer,

4) forming a completed subgap layer and insulating the coil layer and planarizing as required,

5) forming a second pole layer,

6) depositing an overcoat layer and planarizing the overcoat layer as required,

7) etching a window to the coil terminations and plating the termination studs up the surface of the thick overcoat layer,

8) slicing sections of the wafer into row bars which contain a plane perpendicular to the first plane of processing that will form the second major plane of processing.

B) A second major plane of processing perpendicular to the first plane of processing which comprises

1) lapping and polishing the second plane to nominal gap depth or coil depth,

2) depositing and processing upon the second plane a soft permeable magnetic surface film head layer which contains an arbitrary gap pattern and arbitrary surface film pattern.

19. The method of claim 18, wherein the magnetic surface film is plated up with the gaps defined by a plating pattern and selectively plating the gap pattern in-situ and not requiring a subsequent etching process.

20. The method of claim 18, wherein the magnetic surface gap patterns are defined by a focused ion beam (FIB), process subsequent to the magnetic surface film deposition.

21. The method of claim 18, wherein the magnetic surface film gap pattern is defined by sputtering the surface film over a previously defined gap and using a lift-off process to remove stray film deposition.

22. The method of claim 18, wherein the writing gaps have curved or slanted termination features that prevent the writing of stray marks on the medium outside the gaps.

23. The method of claim 18, wherein the surface thin film spans the leading edge to the trailing edge of the head surface.

24. The method of claim 18, wherein the thin film is only located between air bleed slots cut into the head.

25. The method of claim 18, wherein the thin film is only located substantially over the subgap and in-between the subpoles.

26. The method of claim 18, wherein the pattern is a timing based servo pattern.

27. The method of claim 18, wherein the pattern is an amplitude based servo pattern.

28. The method of claim 18, wherein the pattern is a combination of a timing based and an amplitude based servo pattern.

29. Magnetic tape comprising a pattern that serves as servo data written on the tape by a surface film magnetic recording head comprising

the pattern formed by at least one recording gap, the pattern is located between a pair of magnetically permeable thin film subpole members and contained within a magnetically permeable surface film between the pair of magnetically permeable thin film subpole members, thereby forming a magnetic circuit;

the magnetic circuit adapted to conduct magnetic flux for a particular state of current through the pair of magnetically permeable thin film subpole members and the magnetically permeable surface film, with some of the magnetic flux leaking over the at least one gap and makes contact with the magnetic tape, whereby the pattern is written on the tape.

30. The magnetic tape of claim 29, wherein the pattern is a timing based servo pattern.

31. The magnetic tape of claim 29, wherein the pattern is an amplitude based servo pattern.

32. The magnetic tape of claim 29, wherein the pattern is a combination of a timing based and an amplitude based servo pattern.

33. A highly permeable magnetic surface film layer which spans from at least the first magnetically permeable thin film subpole member to the second magnetically permeable thin film subpole member includes a pattern formed by at least one gap;

a coil structure in at least one layer located in part within the subgap and defining a coil depth distance to the first coil turn below the subgap surface.

34. The recording head of claim 33, wherein the first magnetically permeable thin film subpole member and the second magnetically permeable thin film subpole member form an apex point which defines a gap depth and to which is related by a precision layout a distance to the first coil turn below the subgap surface.

35. The recording head of claim 33, wherein the coil structure is a multi-layer.

36. The recording head of claim 33, wherein the coil structure is a single layer.

37. An integrated surface film magnetic recording head having at least one element, comprising:

a pair of magnetically permeable thin film subpole members, separated by a substantially low permeability subgap member, the gap member and pole members forming a subgap, subpole substrate for the formation on top thereof of a highly permeable magnetic surface film layer into which arbitrary recording gap features are placed.