Polishing method of soft magnetic layer in thin-film magnetic head, manufacturing method of thin-film magnetic head and thin-film magnetic head

Abstract

A polishing method includes the steps of, performing a chemical-mechanical polishing with a first acid slurry, in the case of polishing soft magnetic layer with iron alloy that contains silicon and aluminum, and performing a mechanical polishing with a second weak acid or neutral slurry with a pH different from that of the first slurry.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows an oblique view schematically illustrating a configuration of a multi channel magnetic tape device as an embodiment according to the present invention;

FIG. 2 shows an enlarged oblique view illustrating a configuration of a thin-film magnetic head and this peripheral part shown in FIG. 1;

FIG. 3 shows an oblique view schematically illustrating a configuration of the thin-film magnetic head shown in FIG. 1;

FIG. 4 shows a side view seen from a TBS direction schematically illustrating a configuration of each write/read magnetic head element of the thin-film magnetic head shown in FIG. 1;

FIG. 5 a to 5h show process sectional view schematically illustrating a part of wafer manufacturing process of the thin-film magnetic head shown in FIG. 1;

FIG. 6 shows a view of relation between an asymmetry standard deviation of a MR output and a bit error rate; and

FIG. 7 shows a view of relation between a surface roughness Ra of a lower shield layer and the asymmetry standard deviation of the MR output.

Claims

1. A polishing method of a soft magnetic layer in a thin-film magnetic head comprising the steps of: performing a chemical-mechanical polishing with a first acid slurry, in the case of polishing the soft magnetic layer with iron alloy that contains silicon and aluminum;performing a mechanical polishing with a second weak acid or neutral slurry with a pH different from that of the first slurry.

2. The polishing method as claimed in claim 1, wherein said chemical-mechanical polishing and said mechanical polishing perform on the same polishing equipment.

3. The polishing method as claimed in claim 1, wherein said soft magnetic layer is the soft magnetic layer with a columnar crystal structure.

4. The polishing method as claimed in claim 1, wherein said first slurry contains aluminum oxide as a polishing agent, and further contains organic acid.

5. The polishing method as claimed in claim 4, wherein a pH of said first slurry is from 3.7 to 4.3.

6. The polishing method as claimed in claim 1, wherein said second slurry contains aluminum oxide as a polishing agent, and further contains nitric acid chemical compound.

7. The polishing method as claimed in claim 6, wherein a pH of said second slurry is from 6 to 7.

8. The polishing method as claimed in claim 1, wherein said soft magnetic layer is a lower shield layer of a magnetoresistive effect read head element.

9. A manufacturing method of a thin-film magnetic head comprising the steps of: laminating and patterning a soft magnetic layer with iron alloy that contains silicon and aluminum through a base layer on a substrate;laminating an insulating layer on said patterned soft magnetic layer;performing a chemical-mechanical polishing a surface of said laminated insulating layer and said patterned soft magnetic layer with a first acid slurry;forming a lower shield layer by a mechanical polishing with a second weak acid or neutral slurry with a pH different from that of the first slurry;forming a lower shield gap layer and a magnetoresistive effect layer on that layer.

10. The manufacturing method as claimed in claim 9, wherein said chemical-mechanical polishing and said mechanical polishing perform on the same polishing equipment.

11. The manufacturing method as claimed in claim 9, wherein said soft magnetic layer is the magnetic layer with a columnar crystal structure.

12. The manufacturing method as claimed in claim 9, wherein said first slurry contains aluminum oxide as a polishing agent, and further contains organic acid.

13. The manufacturing method as claimed in claim 12, wherein a pH of said first slurry is from 3.7 to 4.3.

14. The manufacturing method as claimed in claim 9, wherein said second slurry contains aluminum oxide as a polishing agent, and further contains nitric acid chemical compound.

15. The manufacturing method as claimed in claim 14, wherein a pH of said second slurry is from 6 to 7.

16. The manufacturing method as claimed in claim 9, wherein said manufacturing method further comprises the steps of: stacking an upper shield gap layer on said lower shield gap layer and said magnetoresistive effect layer;stacking an upper shield layer on said upper shield gap layer.

17. The manufacturing method as claimed in claim 16, wherein said manufacturing method further comprises the step of: forming an inductive write head element on said upper shield layer.

18. A thin-film magnetic head comprising: a lower shield layer with iron alloy that contains silicon and aluminum stacked through a base layer on a substrate;a lower shield gap layer formed on said lower shield layer;a magnetoresistive effect layer formed on said lower shield gap layer;an upper shield gap layer formed on said magnetoresistive effect layer and said lower shield gap layer;an upper shield layer formed on said upper shield gap layer,with a surface of said lower shield layer being planarized as a surface roughness is less than or equal 1 nm.

19. The thin-film magnetic head as claimed in claim 18, wherein said thin-film magnetic head further comprises: an inductive write head element formed on said upper shield layer.