METHODS FOR PRODUCING AND/OR TESTING MAGNETIC HEADS USING CLASSIFICATIONS

• US 20110134559A1
• Filed: 12/08/2010
• Published: 06/09/2011
• Est. Priority Date: 12/09/2009
• Status: Active Grant

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Hitachi Global Storage Technologies Netherlands BV (Western Digital Corporation)
• Inventors: Ono, Makoto, Ueda, Fumiomi
• Granted Patent: US 8,552,716 B2
• Time in Patent Office: Days
• US Class Current: 360/31
• CPC Class Codes: G11B 5/455 Arrangements for functional testing of heads; Measuring arrangements for heads
• CPC Class Codes: Y10T 29/49032 Fabricating head structure or component thereof

Abstract

In one embodiment, a manufacturing method for magnetic heads includes classifying magnetic heads into one of a first tested head class, and a non-test-candidate head class, determining characteristic values of the magnetic heads classified in the first tested head class, estimating characteristic values of the magnetic heads classified in the non-test-candidate head class, wherein the estimating is based on the characteristic values of the magnetic heads classified in the first tested head class, classifying each of the magnetic heads classified in the non-test-candidate head class into one of: a second tested head class, and a non-test head class based on the estimated characteristic values, determining characteristic values of the magnetic heads classified in the second tested head class, and screening magnetic heads in the second tested head class based on the determined characteristic values of the magnetic heads classified in the second tested head class.

Claims

1. A manufacturing method for magnetic heads, comprising:

classifying each of a plurality of magnetic heads into one of;

a first tested head class, and a non-test-candidate head class;

determining characteristic values of the magnetic heads classified in the first tested head class;

screening magnetic heads in the first tested head class based on the determined characteristic values of the magnetic heads classified in the first tested head class;

estimating characteristic values of the magnetic heads classified in the non-test-candidate head class, wherein the estimating is based on the characteristic values of the magnetic heads classified in the first tested head class;

classifying each of the magnetic heads classified in the non-test-candidate head class into one of;

a second tested head class, and a non-test head class, wherein the classifying is based on the estimated characteristic values of the magnetic heads classified in the non-test-candidate head class;

determining characteristic values of the magnetic heads classified in the second tested head class; and

screening magnetic heads in the second tested head class based on the determined characteristic values of the magnetic heads classified in the second tested head class.

2. The method as recited in claim 1, wherein classifying the magnetic heads classified in the non-test-candidate head class comprises using criteria that are different from criteria used for screening.

3. The method as recited in claim 1, further comprising screening magnetic heads in the first tested head class based on the determined characteristic values of the magnetic heads classified in the first tested head class.

4. The method as recited in claim 1, further comprising screening magnetic heads in the non-test-candidate head class based on the estimated characteristic values of the magnetic heads classified in the non-test-candidate head class.

5. The method as recited in claim 1, wherein estimating characteristic values of the magnetic heads classified in the non-test-candidate head class further comprises using characteristic values of the magnetic heads classified in the first tested head class in a rowbar along with characteristic values of other magnetic heads in the rowbar to interpolate characteristic values of the magnetic heads classified in the non-test-candidate head class, wherein the rowbar comprises a linear arrangement of a plurality of magnetic heads.

6. The method as recited in claim 1, wherein estimating characteristic values of the magnetic heads classified in the non-test-candidate head class further comprises using a difference between pairs of characteristic values corresponding to one position in the rowbar of the magnetic heads classified in the first tested head class in a rowbar and of a profile of characteristic values of other magnetic heads produced previously, wherein the rowbar comprises a linear arrangement of a plurality of magnetic heads.

7. The method as recited in claim 1, further comprising:

applying flag information indicating that a component is to be tested to the characteristic values of the magnetic heads classified in the first tested head class and the magnetic heads classified in the second tested head class;

applying flag information indicating that a component is not to be tested to the characteristic values of components of magnetic heads in the non-test head class which are estimated from the characteristic values of magnetic heads in the tested head class; and

reading out the characteristic values of the tested components and the non-tested components and the corresponding flag information of these components by using serial numbers applied to each of the magnetic heads as search keys.

8. A manufacturing method for magnetic storage device assembled with one or more magnetic heads, the method comprising:

preparing a substrate for forming a plurality of magnetic heads thereon;

forming the plurality of magnetic heads on the substrate;

assembling the plurality of magnetic heads into magnetic storage devices;

testing at least some of the plurality of magnetic heads to obtain characteristic values;

estimating characteristic values of non-tested magnetic heads on which testing is not performed using the characteristic values of the tested magnetic heads;

classifying the non-tested magnetic heads based on the estimated characteristic values;

assembling the magnetic heads classified as non-tested magnetic heads into the magnetic storage devices according to assembly rules;

measuring performance of the magnetic storage devices assembled with the non-tested magnetic heads; and

screening the magnetic storage devices assembled with the non-tested magnetic heads.

9. A system, comprising:

logic adapted for classifying each of a plurality of magnetic heads into one of;

a first tested head class, and a non-test-candidate head class;

logic adapted for determining characteristic values of the magnetic heads classified in the first tested head class;

logic adapted for estimating characteristic values of the magnetic heads classified in the non-test-candidate head class, wherein the estimating is based on the characteristic values of the magnetic heads classified in the first tested head class;

logic adapted for classifying each of the magnetic heads classified in the non-test-candidate head class into one of;

a second tested head class, and a non-test head class, wherein the classifying is based on the estimated characteristic values of the magnetic heads classified in the non-test-candidate head class;

logic adapted for determining characteristic values of the magnetic heads classified in the second tested head class; and

logic adapted for screening magnetic heads in the second tested head class based on the determined characteristic values of the magnetic heads classified in the second tested head class.

10. The system as recited in claim 9, wherein the logic adapted for classifying the magnetic heads classified in the non-test-candidate head class comprises using criteria that are different from criteria used for screening.

11. The system as recited in claim 9, further comprising logic adapted for screening magnetic heads in the first tested head class based on the determined characteristic values of the magnetic heads classified in the first tested head class.

12. The system as recited in claim 9, further comprising logic adapted for screening magnetic heads in the non-test-candidate head class based on the estimated characteristic values of the magnetic heads classified in the non-test-candidate head class.

13. The system as recited in claim 9, wherein the logic adapted for estimating characteristic values of the magnetic heads classified in the non-test-candidate head class further comprises using characteristic values of the magnetic heads classified in the first tested head class in a rowbar along with characteristic values of other magnetic heads in the rowbar to interpolate characteristic values of the magnetic heads classified in the non-test-candidate head class, wherein the rowbar comprises a linear arrangement of a plurality of magnetic heads.

14. The system as recited in claim 9, wherein the logic adapted for estimating characteristic values of the magnetic heads classified in the non-test-candidate head class further comprises using a difference between pairs of characteristic values corresponding to one position in the rowbar of the magnetic heads classified in the first tested head class in a rowbar and of a profile of characteristic values of other magnetic heads produced previously, wherein the rowbar comprises a linear arrangement of a plurality of magnetic heads.

15. The system as recited in claim 9, further comprising:

logic adapted for applying flag information indicating that a component is to be tested to the characteristic values of the magnetic heads classified in the first tested head class and the magnetic heads classified in the second tested head class;

logic adapted for applying flag information indicating that a component is not to be tested to the characteristic values of components of magnetic heads in the non-test head class which are estimated from the characteristic values of magnetic heads in the tested head class; and

logic adapted for reading out the characteristic values of the tested components and the non-tested components and the corresponding flag information of these components by using serial numbers applied to each of the magnetic heads as search keys.

16. A computer program product, the computer program product comprising:

computer readable medium having computer readable code stored thereon, the computer readable medium comprising;

computer readable code adapted for classifying each of a plurality of magnetic heads into one of;

a first tested head class, and a non-test-candidate head class;

computer readable code adapted for determining characteristic values of the magnetic heads classified in the first tested head class;

computer readable code adapted for estimating characteristic values of the magnetic heads classified in the non-test-candidate head class, wherein the estimating is based on the characteristic values of the magnetic heads classified in the first tested head class;

computer readable code adapted for classifying each of the magnetic heads classified in the non-test-candidate head class into one of;

a second tested head class, and a non-test head class, wherein the classifying is based on the estimated characteristic values of the magnetic heads classified in the non-test-candidate head class;

computer readable code adapted for determining characteristic values of the magnetic heads classified in the second tested head class; and

computer readable code adapted for screening magnetic heads in the second tested head class based on the determined characteristic values of the magnetic heads classified in the second tested head class.

17. The computer program product as recited in claim 16, wherein the computer readable code adapted for classifying the magnetic heads classified in the non-test-candidate head class comprises using criteria that are different from criteria used for screening.

18. The computer program product as recited in claim 16, further comprising computer readable code adapted for screening magnetic heads in the first tested head class based on the determined characteristic values of the magnetic heads classified in the first tested head class.

19. The computer program product as recited in claim 16, further comprising computer readable code adapted for screening magnetic heads in the non-test-candidate head class based on the estimated characteristic values of the magnetic heads classified in the non-test-candidate head class.

20. The computer program product as recited in claim 16, wherein the computer readable code adapted for estimating characteristic values of the magnetic heads classified in the non-test-candidate head class further comprises using characteristic values of the magnetic heads classified in the first tested head class in a rowbar along with characteristic values of other magnetic heads in the rowbar to interpolate characteristic values of the magnetic heads classified in the non-test-candidate head class, wherein the rowbar comprises a linear arrangement of a plurality of magnetic heads.

21. The computer program product as recited in claim 16, wherein the computer readable code adapted for estimating characteristic values of the magnetic heads classified in the non-test-candidate head class further comprises using a difference between pairs of characteristic values corresponding to one position in the rowbar of the magnetic heads classified in the first tested head class in a rowbar and of a profile of characteristic values of other magnetic heads produced previously, wherein the rowbar comprises a linear arrangement of a plurality of magnetic heads.

22. The computer program product as recited in claim 16, further comprising:

computer readable code adapted for applying flag information indicating that a component is to be tested to the characteristic values of the magnetic heads classified in the first tested head class and the magnetic heads classified in the second tested head class;

computer readable code adapted for applying flag information indicating that a component is not to be tested to the characteristic values of components of magnetic heads in the non-test head class which are estimated from the characteristic values of magnetic heads in the tested head class; and

computer readable code adapted for reading out the characteristic values of the tested components and the non-tested components and the corresponding flag information of these components by using serial numbers applied to each of the magnetic heads as search keys.