Method of making a thin film magnetic head having multi-layer coils

• US 5,448,822 A
• Filed: 03/10/1993
• Issued: 09/12/1995
• Est. Priority Date: 03/10/1993
• Status: Expired due to Term

• Current Assignee: Maxtor Corporation (Seagate Technology Holdings Plc)
• Original Assignee: Quantum Corporation (Chi Ko Investment Co., Ltd.)
• Inventors: Wu, Andrew L., Duval, Paul J.
• Primary Examiner(s): Hall, Carl E.
• Application Number:
  US08/029,125
• Time in Patent Office: 916 Days
• Field of Search: 29/603, 427/116, 427/131, 427/132, 430/324, 430/326
• US Class Current: 29/603.24
• CPC Class Codes: G11B 5/313 Disposition of layers
• 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: H01F 41/042 by thin film techniques
• CPC Class Codes: Y10T 29/49062 Multilayered winding

Abstract

A method of making a thin film magnetic head having multi-layer coils wherein a raised insulative photoresist spiral pattern having undercut sidewalls is formed. Two layers of coils are fabricated simultaneously by evaporating metal onto the upper surface of the spiral pattern and in spaces between the pattern. The cross-section of the bottom coil decreases in width with an increase in height. The coils are insulated from each other with a layer of insulative photoresist.

Claims

1. A method of making at least two coils formed of metal windings and wherein a first coil is disposed below a second coil and wherein the windings of the first coil are aligned between, and insulated from, the windings of the second coil comprising the steps of:

a) forming a first insulative layer;

b) rendering predetermined areas of the first layer more soluble than other areas and wherein the solubility varies along the thickness of the first layer;

c) dissolving the more soluble areas of the first layer to produce a pattern of insulation at predetermined locations where the windings for the second coil are to be formed, leaving spaces therebetween, said pattern varying in width from larger to smaller from an upper surface of the first layer to a lower surface;

d) depositing coil metallization on said pattern such that the windings of the second coil are formed on the top of the pattern and then windings of the first coil are formed in the space between the pattern; and

e) forming an insulative layer over the metallization.

2. The method of claim 1 in which the first insulative layer is formed of a resist.

3. The method of claim 2 in which the resist is an image reversal photoresist.

4. The method of claim 3 in which the photoresist is baked a first time prior to exposure and baked a second time after the exposure.

5. The method of claim 1 in which step (e) includes forming a low viscosity resist layer to fill up any voids between the coils and the pattern.

6. The method of claim 1 further comprising forming an upper pole over one portion of the first and second coil windings and a lower pole under adjacent portions of the first and second coil windings.

7. The method of claim 1 in which the first and second coils wind in the same direction.

8. The method of claim 1 further comprising forming a jumper from one end of the second coil winding to an opposite end of the first coil winding.

9. The method of claim 1 in which the first and second coils are spirally wound about a horseshoe shaped magnet formed of an upper pole piece and a lower pole piece separated at one end by a gap.

10. The method of claim 1 further comprising depositing a low viscosity insulator to fill any voids existing between the bottom coil and the sidewalls of the pattern.

11. A method of making multi-layer coils for a magnetic head comprising the steps of:

forming a raised substantially convoluted photoresist pattern, said pattern having a base and an upper surface connected to the base by sidewalls, the upper surface of the pattern being wider across the sidewalls than the base, wherein the width of the base of the pattern is made smaller by under-exposing the photoresist pattern;

depositing a layer of metal over the pattern to form a top coil having windings on the upper surface of the pattern and a bottom coil having windings between the pattern; and

depositing an insulator on the top and bottom coils.

12. The method of claim 11 in which the sidewalls of the pattern are linearly sloped.

13. The method of claim 11 further comprising chemically treating the upper surface of the photoresist to harden the upper surface.

14. The method of claim 13 in which the sidewall is formed with a step.

15. The method of claim 11 further comprising:

connecting the top and bottom coils together in electrical series; and

connecting the top and bottom coils to an electrical power source.

16. The method of claim 11 in which the top and bottom coils are wound about a core of ferromagnetic material.

17. The method of claim 11 in which the top coil windings are aligned between the bottom coil windings.

18. A method of making multi-layer coils comprising:

forming a raised substantially convoluted photoresist pattern, the convoluted pattern having a base and an upper convoluted surface connected to the base by sidewalls with a lower convoluted surface between and adjacent to the upper convoluted surface wherein the width of the base is made smaller by under-exposing the photoresist pattern;

depositing a layer of metal over the pattern to form a top coil having windings on the upper convoluted surface, the windings of the top coil having a width and a height; and

a bottom coil having windings on the lower convoluted surface, the windings of the bottom coil having a width and a height.

19. The method of claim 18 further comprising depositing an insulator on the top and bottom coils.

20. The method of claim 18 in which the cross-sectional width of the bottom coil winding decreases with the height of the bottom coil winding.

21. The method of claim 18 in which the sidewall is linearly sloped.

22. The method of claim 18 further comprising chemically treating the upper surface of the photoresist to harden the upper surface.

23. The method of claim 18 in which the sidewall is formed with a step.

24. The method of claim 18 further comprising depositing a low viscosity insulator to fill any voids existing between the bottom coil and the sidewalls.

25. The method of claim 18 further comprising:

connecting the top and bottom coils together in electrical series; and

connecting the top and bottom coils to an electrical power source.

26. The method of claim 18 in which the top and bottom coils are wound about a core of ferromagnetic material.

27. The method of claim 18 in which the top coil windings are aligned between the bottom coil windings.