# US 5,702,756 A · Process for making a thin film magnetic head

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- Number: US 5,702,756 A
- Document ID: US5702756A
- Status: Granted
- Kind: A
- Application number: 08/676,693
- Filed: 1996-07-10
- Granted: 1997-12-30
- Earliest claimed: 1994-09-01
- Assignees: International Business Machines Corporation
- Inventors: Dennis Richard McKean; Alfred Floyd Renaldo
- Web page: https://patentgrep.com/patent/US5702756A

## CPC

- G11B 5/3967: {Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read (G11B5/3906 takes precedence)}
- G11B 5/3109: {Details (G11B5/3103 takes precedence)}
- G11B 5/3116: {Shaping of layers, poles or gaps for improving the form of the electrical signal transduced, e.g. for shielding, contour effect, equalizing, side flux fringing, cross talk reduction between heads or between heads and information tracks (G11B5/3113, G11B5/245 take precedence)}
- G11B 5/313: {Disposition of layers}
- 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}
- Y10T 29/49044: Plural magnetic deposition layers
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

An improved process for making thin film magnetic heads using an insulation comprising a polymer, a crosslinking agent, and 4-sulfonate diazonaphthoquinone.

## Claims

### Claim 1

A method for making a thin film magnetic head comprising the steps of:
(a) forming a first pole piece layer of magnetic material;
(b) depositing a gap-forming layer of nonmagnetic material over said first pole piece layer;
(c) depositing a first layer of insulation material on the gap-forming layer;
(d) forming a conductive coil on said first layer of insulating material;
(e) depositing a second layer of insulation material over said conductive coil, the first and second layers of insulation material comprising a phenolic resin polymer, 4-sulfonate diazonaphthoquinone, and less than 20 weight % of a thermally activated melamine formaldehyde resin crosslinking agent;
(f) heating the first and second layers of insulating material to crosslink the polymer; and
(g) depositing a second pole piece layer of magnetic material to complete the magnetic head.

### Claim 2 (depends on 1)

The method of claim 1 wherein the polymer is novolac.

### Claim 3 (depends on 1)

The method of claim 1 wherein the first and second layers of insulating material are heated in step (R) to less than about 200.degree. C. to crosslink the polymer.

### Claim 4 (depends on 1)

The method of claim 1 wherein the first and second layers of insulation material contains less than about 15 weight % of melamine formaldehyde resin.

### Claim 5 (depends on 4)

The method of claim 4 wherein said thin film magnetic head has an apex angle greater than 50 degrees.

### Claim 6

A method for making a thin film magnetic write head of a magnetoresistive read/write head comprising the steps of:
(a) forming a first pole piece layer of magnetic material;
(b) depositing a gap-forming layer of nonmagnetic material over said first pole piece layer;
(c) depositing a first layer of insulation material on the gap-forming layer;
(d) forming a conductive coil on said first layer of insulating material;
(e) depositing a second layer of insulation material over said conductive coil, the first and second layers of insulation material comprising a phenolic resin polymer, 4-sulfonate diazonaphthoquinone, and less than about 20 weight % of a thermally activated melamine formaldehyde resin crosslinking agent;
(f) heating the first and second layers of insulating material to a temperature less than 200.degree. C. to crosslink the polymer; and
(g) depositing a second layer of magnetic material to complete the thin film magnetic write head.

### Claim 7 (depends on 6)

The method of claim 6 wherein the polymer is novolac.

### Claim 8 (depends on 6)

The method of claim 6 wherein the first and second layers of insulation material contains less than about 15 weight % of melamine formaldehyde resin.

### Claim 9

A method for making a thin film magnetic head comprising the steps of:
(a) forming a first pole piece layer of magnetic material;
(b) depositing a gap-forming layer of nonmagnetic material over said first pole piece layer;
(c) depositing a first layer of insulation material on the gap-forming layer;
(d) forming a conductive coil on said first layer of insulating material;
(e) depositing a second layer of insulation material over said conductive coil, the first and second layers of insulation material comprising a phenolic resin polymer, 4-sulfonate diazonaphthoquinone, and less than 20 weight % of a thermally activated glycol urea crosslinking agent;
(f) heating the first and second layers of insulating material to crosslink the polymer; and
(g) depositing a second pole piece layer of magnetic material to complete the magnetic head.

### Claim 10 (depends on 9)

The method of claim 9 wherein the first and second layers of insulating material is heated in step (f) to less than about 200.degree. C. to crosslink the polymer.

### Claim 11 (depends on 9)

The method of claim 9 wherein the 4-sulfonate diazonaphthoquinone is 4-(phenylcumyl sulfonate) diazonaphthoquinone.