Method of manufacturing thin-film magnetic head Number:7,155,809 from the United States Patent and Trademark Office (PTO) owispatent A method of manufacturing a thin-film magnetic head comprises the steps of forming a first pole layer, forming a gap layer on a pole portion of the first pole layer, and forming a second pole layer on the gap layer. The second pole layer incorporates a first layer adjacent to the gap layer, and a second layer including a track width defining portion. The step of forming the second pole layer includes the steps of: forming a magnetic layer for forming the first layer on the gap layer; forming the second layer on the magnetic layer; and etching the magnetic layer to align with a width of the track width defining portion, so that the magnetic layer is formed into the first layer and the width of each of the first layer and the second layer taken in a medium facing surface is made equal to the track width.<H manufacturing, magnetic, Method, of, manuf, 7155809.html, Patent, pto, 7155809

Title: Method of manufacturing thin-film magnetic head

Abstract: A method of manufacturing a thin-film magnetic head comprises the steps of forming a first pole layer, forming a gap layer on a pole portion of the first pole layer, and forming a second pole layer on the gap layer. The second pole layer incorporates a first layer adjacent to the gap layer, and a second layer including a track width defining portion. The step of forming the second pole layer includes the steps of: forming a magnetic layer for forming the first layer on the gap layer; forming the second layer on the magnetic layer; and etching the magnetic layer to align with a width of the track width defining portion, so that the magnetic layer is formed into the first layer and the width of each of the first layer and the second layer taken in a medium facing surface is made equal to the track width.

Patent Number: 7,155,809 Issued on 01/02/2007 to Sasaki, et al.

Inventors: Sasaki; Yoshitaka (Milpitas, CA), Itoh; Hiroyuki (Milpitas, CA), Kamigama; Takehiro (Hong Kong, HK)
Assignee: Headway Technologies, Inc (Milpitas, CA)
SAE Magnetics (H.K.) Ltd. (Hong Kong, HK)

Appl. No.: 11/401,955

Filed: April 12, 2006

Current U.S. Class: 29/603.12 ; 29/603.13; 29/603.14; 29/603.15; 29/603.18; 29/603.23; 360/126

Current International Class: G11B 5/127 (20060101); G11B 5/147 (20060101)

Field of Search: 29/603.12,603.13,603.14,603.15,603.18,603.23 360/126,317,122,123,125 216/22,63,39,49,41

References Cited [Referenced By]

U.S. Patent Documents


5793578	August 1998	Heim et al.
6043959	March 2000	Crue et al.
6043960	March 2000	Chang et al.
6069775	May 2000	Chang et al.
6151193	November 2000	Terunuma et al.
6163436	December 2000	Sasaki et al.
6259583	July 2001	Fontana, Jr. et al.
6400525	June 2002	Sasaki et al.
6560068	May 2003	Sasaki

Foreign Patent Documents


A 2001-52311	Feb., 2001	JP

Primary Examiner: Tugbang; A. Dexter
Assistant Examiner: Nguyen; Tai Van
Attorney, Agent or Firm: Oliff & Berridge, PLC

Parent Case Text

This is a Divisional of application Ser. No. 10/702,512 filed Nov. 7, 2003. The entire disclosure of the prior application is hereby incorporated by reference herein in its entirety.

Claims

What is claimed is:

1. A method of manufacturing a thin-film magnetic head comprising: a medium facing surface that faces toward a recording medium; a first pole layer and a second pole layer that are magnetically coupled to each other and include magnetic pole portions opposed to each other and located in regions of the pole layers on a side of the medium facing surface; a gap layer provided between the pole portion of the first pole layer and the pole portion of the second pole layer; and a thin-film coil, at least part of the coil being disposed between the first and second pole layers and insulated from the first and second pole layers, wherein: the first pole layer has a surface facing toward the gap layer, the surface incorporating a first surface including an end portion located in the medium facing surface and an end portion located opposite to the medium facing surface, and a second surface located away from the medium facing surface, the first surface being adjacent to the gap layer, a difference in level being created between the first surface and the second surface, so that the second surface is located farther from the second pole layer than the first surface; the second pole layer incorporates: a first layer disposed adjacent to the gap layer and including an end portion located in the medium facing surface and an end portion located opposite to the medium facing surface; and a second layer disposed on a side of the first layer opposite to the gap layer and including a track width defining portion for defining a track width; each of the first layer and the second layer has a width taken in the medium facing surface that is equal to the track width; and a length of the second layer is greater than a length of the first layer, each of the lengths being taken in a direction orthogonal to the medium facing surface, the method comprising the steps of: forming the first pole layer; forming the thin-film coil on the first pole layer; forming the gap layer on the pole portion of the first pole layer; and forming the second pole layer on the gap layer, the step of forming the second pole layer including the steps of: forming a magnetic layer for forming the first layer on the gap layer; forming the second layer on the magnetic layer; and etching the magnetic layer to align with a width of the track width defining portion, so that the magnetic layer is formed into the first layer and that the width of each of the first layer and the second layer taken in the medium facing surface is made equal to the track width.

2. The method according to claim 1, wherein the step of etching the magnetic layer further includes etching of the gap layer and a portion of the first pole layer to align with the width of the track width defining portion.

3. The method according to claim 1, wherein the second layer is made to be a flat layer.

4. The method according to claim 1, wherein: the gap layer is made of a nonmagnetic inorganic material; and the first layer is etched by reactive ion etching in the step of etching the first layer.

5. The method according to claim 4, wherein the nonmagnetic inorganic material is one of the group consisting of alumina, silicon carbide and aluminum nitride.

6. The method according to claim 1, wherein: the second pole layer further comprises an intermediate layer disposed between the first layer and the second layer, the intermediate layer having a width taken in the medium facing surface that is equal to the track width, the intermediate layer having a length taken in the direction orthogonal to the medium facing surface that is greater than the length of the first layer and smaller than the length of the second layer, the step of forming the second pole layer including the steps of: forming a first magnetic layer for forming the first layer on the gap layer; forming a first mask on the first magnetic layer for forming an end portion of the first magnetic layer opposite to the medium facing surface; forming the end portion of the first magnetic layer and forming the first surface and the second surface of the first pole layer by selectively etching the first magnetic layer, the gap layer and the first pole layer through the use of the first mask; forming a first nonmagnetic layer so as to fill etched portions of the first magnetic layer, the gap layer and the first pole layer while the first mask is left unremoved; removing the first mask after the first nonmagnetic layer is formed; forming a second magnetic layer for forming the intermediate layer on the first magnetic layer and the first nonmagnetic layer after the first mask is removed; forming a second mask on the second magnetic layer for forming an end portion of the second magnetic layer opposite to the medium facing surface; forming the end portion of the second magnetic layer by selectively etching the second magnetic layer through the use of the second mask; forming a second nonmagnetic layer so as to fill an etched portion of the second magnetic layer while the second mask is left unremoved; removing the second mask after the second nonmagnetic layer is formed; forming the second layer on the second magnetic layer and the second nonmagnetic layer after the second mask is removed; and etching the second magnetic layer and the first magnetic layer to align with the width of the track width defining portion, so that the first magnetic layer is formed into the first layer, the second magnetic layer is formed into the intermediate layer, and the width of each of the first layer, the intermediate layer and the second layer that is taken in the medium facing surface is made equal to the track width.

7. The method according to claim 6, wherein the throat height is defined by the end portion of the first layer opposite to the medium facing surface.

8. The method according to claim 6, wherein the step of forming the second pole layer further includes the step of flattening top surfaces of the first magnetic layer and the first nonmagnetic layer by polishing, the step of flattening being provided between the step of removing the first mask and the step of forming the second magnetic layer.

9. The method according to claim 8, wherein a depth to which the polishing is performed in the step of flattening the top surfaces of the first magnetic layer and the first nonmagnetic layer falls within a range of 10 to 50 nm inclusive.

10. The method according to claim 6, wherein the step of forming the second pole layer further includes the step of flattening top surfaces of the second magnetic layer and the second nonmagnetic layer by polishing, the step of flattening being provided between the step of removing the second mask and the step of forming the second layer.

11. The method according to claim 10, wherein a depth to which the polishing is performed in the step of flattening the top surfaces of the second magnetic layer and the second nonmagnetic layer falls within a range of 10 to 50 nm inclusive.

12. The method according to claim 1, wherein: the step of forming the first pole layer includes the steps of: forming a first mask for forming the first surface and the second surface of the first pole layer on the gap layer; forming the first surface and the second surface by selectively etching the gap layer and a portion of the first pole layer through the use of the first mask; forming a first nonmagnetic layer so as to fill etched portions of the gap layer and the first pole layer while the first mask is left unremoved; and removing the first mask after the first nonmagnetic layer is formed; and the step of forming the second pole layer includes the steps of: forming a magnetic layer for forming the first layer on the gap layer and the first nonmagnetic layer after the first mask is removed; forming a second mask on the magnetic layer for forming an end portion of the magnetic layer opposite to the medium facing surface; forming the end portion of the magnetic layer by selectively etching the magnetic layer through the use of the second mask; forming a second nonmagnetic layer so as to fill an etched portion of the magnetic layer while the second mask is left unremoved; removing the second mask after the second nonmagnetic layer is formed; forming the second layer on the magnetic layer and the second nonmagnetic layer after the second mask is removed; and etching the magnetic layer to align with the width of the track width defining portion, so that the magnetic layer is formed into the first layer and that the width of each of the first layer and the second layer that is taken in the medium facing surface is made equal to the track width.

13. The method according to claim 12, wherein; an end portion of the gap layer opposite to the medium facing surface is formed by the etching of the gap layer; and the throat height is defined by a position in which the end portion of the gap layer is in contact with the first magnetic layer.

14. The method according to claim 12, wherein the step of forming the second pole layer further includes the step of flattening a top surface of the magnetic layer by polishing before the second mask is formed on the magnetic layer.

15. The method according to claim 14, wherein a depth to which the polishing is performed in the step of flattening the top surface of the magnetic layer falls within a range of 10 to 50 nm inclusive.

16. The method according to claim 12, wherein the step of forming the second pole layer further includes the step of flattening top surfaces of the magnetic layer and the second nonmagnetic layer by polishing, the step of flattening being provided between the step of removing the second mask and the step of forming the second layer.

17. The method according to claim 16, wherein a depth to which the polishing is performed in the step of flattening the top surfaces of the magnetic layer and the second nonmagnetic layer falls within a range of 10 to 50 nm inclusive.

18. The method according to claim 1, wherein: the step of forming the first pole layer includes the steps of: forming a first mask for forming the first surface and the second surface of the first pole layer on the first pole layer; forming the first surface and the second surface by selectively etching a portion of the first pole layer through the use of the first mask; forming a first nonmagnetic layer so as to fill an etched portion of the first pole layer while the first mask is left unremoved; and removing the first mask after the first nonmagnetic layer is formed; and the step of forming the second pole layer includes the steps of: forming a magnetic layer for forming the first layer on the gap layer; forming a second mask on the magnetic layer for forming an end portion of the magnetic layer opposite to the medium facing surface; forming the end portion of the magnetic layer by selectively etching the magnetic layer through the use of the second mask; forming a second nonmagnetic layer so as to fill an etched portion of the magnetic layer while the second mask is left unremoved; removing the second mask after the second nonmagnetic layer is formed; forming the second layer on the magnetic layer and the second nonmagnetic layer after the second mask is removed; and etching the magnetic layer to align with the width of the track width defining portion, so that the magnetic layer is formed into the first layer and that the width of each of the first layer and the second layer that is taken in the medium facing surface is made equal to the track width.

19. The method according to claim 18, wherein: the throat height is defined by the end portion of the first layer opposite to the medium facing surface; and the end portion of the first surface of the first pole layer opposite to the medium facing surface is located farther from the medium facing surface than the end portion of the first layer opposite to the medium facing surface.

20. The method according to claim 18, wherein the step of forming the first pole layer further includes the step of flattening top surfaces of the first pole layer and the first nonmagnetic layer by polishing after the first mask is removed.

21. The method according to claim 20, wherein a depth to which the polishing is performed in the step of flattening the top surfaces of the first pole layer and the first nonmagnetic layer falls within a range of 10 to 50 nm inclusive.

22. The method according to claim 18, wherein the step of forming the second pole layer further includes the step of flattening top surfaces of the magnetic layer and the second nonmagnetic layer by polishing, the step of flattening being provided between the step of removing the second mask and the step of forming the second layer.

23. The method according to claim 22, wherein a depth to which the polishing is performed in the step of flattening the top surfaces of the magnetic layer and the second nonmagnetic layer falls within a range of 10 to 50 nm inclusive.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a thin-film magnetic head having at least an induction-type electromagnetic transducer and a method of manufacturing such a thin-film magnetic head.

2. Description of the Related Art

Recent years have seen significant improvements in the areal recording density of hard disk drives. In particular, areal recording densities of latest hard disk drives have reached 100 to 160 gigabytes per platter and are even exceeding that level. It is required to improve the performance of thin-film magnetic heads, accordingly.

Among the thin-film magnetic heads, widely used are composite thin-film magnetic heads made of a layered structure including a recording (write) head having an induction-type electromagnetic transducer for writing and a reproducing (read) head having a magnetoresistive element (that may be hereinafter called an MR element) for reading.

In general, the write head incorporates: a medium facing surface (an air bearing surface) that faces toward a recording medium; a bottom pole layer and a top pole layer that are magnetically coupled to each other and include magnetic pole portions opposed to each other and located in regions of the pole layers on a side of the medium facing surface; a write gap layer provided between the magnetic pole portions of the top and bottom pole layers; and a thin-film coil at least part of which is disposed between the top and bottom pole layers and insulated from the top and bottom pole layers.

Higher track densities on a recording medium are essential to enhancing the recording density among the performances of the write head. To achieve this, it is required to implement the write head of a narrow track structure in which the track width, that is, the width of the two magnetic pole portions opposed to each other with the write gap layer disposed in between, the width being taken in the medium facing surface, is reduced down to microns or the order of submicron. Semiconductor process techniques are utilized to achieve the write head having such a structure. In addition, many write heads have a trim structure to prevent an increase in the effective track width due to expansion of a magnetic flux generated in the pole portions in the medium facing surface. The trim structure is a configuration in which the pole portion of the top pole layer, the write gap layer and a portion of the bottom pole layer have the same width taken in the medium facing surface. This structure is formed by etching the write gap layer and the portion of the bottom pole layer, using the pole portion of the top pole layer as a mask.

One of the performance characteristics required for the write head is an excellent overwrite property that is one of the characteristics required for overwrite. To improve the overwrite property, it is required that as many magnetic lines of flux passing through the two pole layers as possible be introduced to the pole portions so as to generate a magnetic field as large as possible near the write gap layer in the medium facing surface. Therefore, to improve the overwrite property, it is effective to employ a material having a high saturation flux density for the magnetic material of the pole portions, and to reduce the throat height. The throat height is the length (height) of the pole portions, that is, the portions of the two pole layers opposed to each other with the write gap layer in between, as taken from the medium-facing-surface-side end to the other end. The zero throat height level is the level of the end (opposite to the medium facing surface) of the portions of the two pole layers opposed to each other with the write gap layer in between. To improve the overwrite property, it is also effective to increase the distance between the two pole layers in a region farther from the medium facing surface than the zero throat height level.

However, a problem arises if many lines of flux are introduced to the pole portions to improve the overwrite property. The problem is that lines of flux leak from portions in the medium facing surface other than the neighborhood of the write gap layer, and the flux leakage causes side write and side erase. Side write is that data is written in a track adjacent to the intended track. Side erase is that data written in a track adjacent to the intended track is erased. To reduce the occurrences of side write and side erase, it is effective to increase the difference in levels of the bottom pole layer in the trim structure, that is, the difference between the level of a portion of an end face of the bottom pole layer exposed in the medium facing surface, the portion touching the write gap layer, and the level of portions on both sides.

The throat height may be determined by forming a stepped portion in the bottom or top pole layer. Methods of determining the throat height by forming a stepped portion in the bottom pole layer are disclosed in, for example, the U.S. Pat. No. 6,259,583B1, the U.S. Pat. No. 6,400,525B1, and the U.S. Pat. No. 5,793,578. Methods of determining the throat height by forming a stepped portion in the top pole layer are disclosed in, for example, the U.S. Pat. No. 6,043,959 and the U.S. Pat. No. 6,560,068B1.

The following problem arises if the throat height is determined by forming a stepped portion in the bottom pole layer. To improve the overwrite property, it is effective to reduce the throat height and to increase the difference in levels in the bottom pole layer that determines the throat height. To reduce the occurrences of side write and side erase, it is effective to increase the difference in levels of the bottom pole layer in the trim structure. To achieve this, however, the volume of the portion of the bottom pole layer located between the side portions forming the trim structure is extremely reduced. At the same time, the cross-sectional area of the magnetic path abruptly decreases in the neighborhood of the boundary between the above-mentioned portion of the bottom pole layer and the other portions. As a result, the flux saturates in the neighborhood of the boundary and the overwrite property is reduced. Furthermore, the end face of the bottom pole layer exposed in the medium facing surface has a width that abruptly changes at the bottom of the stepped portion of the trim structure. Consequently, the flux leaks from the neighborhood of the bottom of the stepped portion of the trim structure toward the recording medium, which causes side write and side erase.

In the case in which the throat height is determined by forming a stepped portion in the top pole layer, too, a problem is that the overwrite property is reduced if the cross-sectional area of the magnetic path of the top pole layer abruptly decreases in the neighborhood of the medium facing surface.

The following problem also arises if the throat height is determined by forming a stepped portion in the top pole layer. In prior art the stepped portion of the top pole layer that determines the throat height is formed as follows. A pole portion layer that determines the throat height is first formed on the write gap layer. Next, an insulating layer is formed to cover the pole portion layer and the write gap layer. The insulating layer is polished so that the top surface of the pole portion layer is exposed. According to this method, the thickness of the pole portion layer varies, depending on the depth removed by the above-mentioned polishing. It is therefore difficult to precisely control the writing characteristics of the head if this method is employed.

OBJECT AND SUMMARY OF THE INVENTION

It is an object of the invention to provide a thin-film magnetic head and a method of manufacturing the same to reduce the occurrences of side write and side erase and to improve the overwrire property of the thin-film magnetic head.

A thin-film magnetic head of the invention comprises: a medium facing surface that faces toward a recording medium; a first pole layer and a second pole layer that are magnetically coupled to each other and include magnetic pole portions opposed to each other and located in regions of the pole layers on a side of the medium facing surface; a gap layer provided between the pole portion of the first pole layer and the pole portion of the second pole layer; and a thin-film coil, at least part of the coil being disposed between the first and second pole layers and insulated from the first and second pole layers. The first pole layer has a surface facing toward the gap layer, the surface incorporating a first surface including an end portion located in the medium facing surface and an end portion located opposite to the medium facing surface, and a second surface located away from the medium facing surface. The first surface is adjacent to the gap layer. A difference in level is created between the first surface and the second surface, so that the second surface is located farther from the second pole layer than the first surface. The second pole layer incorporates: a first layer disposed adjacent to the gap layer and including an end portion located in the medium facing surface and an end portion located opposite to the medium facing surface; and a second layer disposed on a side of the first layer opposite to the gap layer and including a track width defining portion for defining a track width. Each of the first layer and the second layer has a width taken in the medium facing surface that is equal to the track width. The length of the second layer is greater than the length of the first layer, each of the lengths being taken in a direction orthogonal to the medium facing surface.

According to the thin-film magnetic head of the invention, the first pole layer may include a portion adjacent to the gap layer, the portion having a width taken in the medium facing surface that is equal to the track width. The second layer may be a flat layer.

The thin-film magnetic head of the invention may further comprise an intermediate layer disposed between the first layer and the second layer. In this case, it is possible that the intermediate layer has a width taken in the medium facing surface that is equal to the track width, and the length of the intermediate layer taken in the direction orthogonal to the medium facing surface is greater than the length of the first layer and smaller than the length of the second layer. In this case, the throat height may be defined by the end portion of the first layer opposite to the medium facing surface.

According to the thin-film magnetic head of the invention, the throat height may be defined by the position in which the first layer is in contact with an end portion of the gap layer opposite to the medium facing surface.

According to the thin-film magnetic head of the invention, it is possible that the throat height is defined by the end portion of the first layer opposite to the medium facing surface and that the end portion of the first surface of the first pole layer opposite to the medium facing surface is located farther from the medium facing surface than the end portion of the first layer opposite to the medium facing surface.

A method of the invention for manufacturing a thin-film magnetic head is a method of manufacturing the thin-film magnetic head of the invention. The method comprises the steps of: forming the first pole layer; forming the thin-film coil on the first pole layer; forming the gap layer on the pole portion of the first pole layer; and forming the second pole layer on the gap layer.

The step of forming the second pole layer includes the steps of: forming a magnetic layer for forming the first layer on the gap layer; forming the second layer on the magnetic layer; and etching the magnetic layer to align with the width of the track width defining portion, so that the magnetic layer is formed into the first layer and that the width of each of the first layer and the second layer taken in the medium facing surface is made equal to the track width.

According to the method of manufacturing the thin-film magnetic head of the invention, the step of etching the magnetic layer may further include etching of the gap layer and a portion of the first pole layer to align with the width of the track width defining portion.

According to the method of the invention, the second layer may be made to be a flat layer.

According to the method of the invention, it is possible that the gap layer is made of a nonmagnetic inorganic material and that the first layer is etched by reactive ion etching in the step of etching the first layer. In this case, the nonmagnetic inorganic material may be one of the group consisting of alumina, silicon carbide and aluminum nitride.

According to the method of the invention, the second pole layer may further comprise an intermediate layer disposed between the first layer and the second layer. In this case, the intermediate layer may have a width taken in the medium facing surface that is equal to the track width, and may have a length taken in the direction orthogonal to the medium facing surface that is greater than the length of the first layer and smaller than the length of the second layer.

According to the method of the invention, the step of forming the second pole layer may include the steps of: forming a first magnetic layer for forming the first layer on the gap layer; forming a first mask on the first magnetic layer for forming an end portion of the first magnetic layer opposite to the medium facing surface; forming the end portion of the first magnetic layer and forming the first surface and the second surface of the first pole layer by selectively etching the first magnetic layer, the gap layer and the first pole layer through the use of the first mask; forming a first nonmagnetic layer so as to fill etched portions of the first magnetic layer, the gap layer and the first pole layer while the first mask is left unremoved; removing the first mask after the first nonmagnetic layer is formed; forming a second magnetic layer for forming the intermediate layer on the first magnetic layer and the first nonmagnetic layer after the first mask is removed; forming a second mask on the second magnetic layer for forming an end portion of the second magnetic layer opposite to the medium facing surface; forming the end portion of the second magnetic layer by selectively etching the second magnetic layer through the use of the second mask; forming a second nonmagnetic layer so as to fill an etched portion of the second magnetic layer while the second mask is left unremoved; removing the second mask after the second nonmagnetic layer is formed; forming the second layer on the second magnetic layer and the second nonmagnetic layer after the second mask is removed; and etching the second magnetic layer and the first magnetic layer to align with the width of the track width defining portion, so that the first magnetic layer is formed into the first layer, the second magnetic layer is formed into the intermediate layer, and the width of each of the first layer, the intermediate layer and the second layer that is taken in the medium facing surface is made equal to the track width.

In this case, the throat height may be defined by the end portion of the first layer opposite to the medium facing surface.

The step of forming the second pole layer may further include the step of flattening the top surfaces of the first magnetic layer and the first nonmagnetic layer by polishing, the step of flattening being provided between the step of removing the first mask and the step of forming the second magnetic layer. The depth to which the polishing is performed in the step of flattening the top surfaces of the first magnetic layer and the first nonmagnetic layer may fall within a range of 10 to 50 nm inclusive. The step of forming the second pole layer may further include the step of flattening the top surfaces of the second magnetic layer and the second nonmagnetic layer by polishing, the step of flattening being provided between the step of removing the second mask and the step of forming the second layer. The depth to which the polishing is performed in the step of flattening the top surfaces of the second magnetic layer and the second nonmagnetic layer may fall within a range of 10 to 50 nm inclusive.

According to the method of the invention, the step of forming the first pole layer may include the steps of: forming a first mask for forming the first surface and the second surface of the first pole layer on the gap layer; forming the first surface and the second surface by selectively etching the gap layer and a portion of the first pole layer through the use of the first mask; forming a first nonmagnetic layer so as to fill etched portions of the gap layer and the first pole layer while the first mask is left unremoved; and removing the first mask after the first nonmagnetic layer is formed.

In addition, the step of forming the second pole layer may include the steps of: forming a magnetic layer for forming the first layer on the gap layer and the first nonmagnetic layer after the first mask is removed; forming a second mask on the magnetic layer for forming an end portion of the magnetic layer opposite to the medium facing surface; forming the end portion of the magnetic layer by selectively etching the magnetic layer through the use of the second mask; forming a second nonmagnetic layer so as to fill an etched portion of the magnetic layer while the second mask is left unremoved; removing the second mask after the second nonmagnetic layer is formed; forming the second layer on the magnetic layer and the second nonmagnetic layer after the second mask is removed; and etching the magnetic layer to align with the width of the track width defining portion, so that the magnetic layer is formed into the first layer and that the width of each of the first layer and the second layer that is taken in the medium facing surface is made equal to the track width.

In this case, it is possible that an end portion of the gap layer opposite to the medium facing surface is formed by the etching of the gap layer and that the throat height is defined by a position in which the end portion of the gap layer is in contact with the first magnetic layer.

The step of forming the second pole layer may further include the step of flattening the top surface of the magnetic layer by polishing before the second mask is formed on the magnetic layer. The depth to which the polishing is performed in the step of flattening the top surface of the magnetic layer may fall within a range of 10 to 50 nm inclusive. The step of forming the second pole layer may further include the step of flattening the top surfaces of the magnetic layer and the second nonmagnetic layer by polishing, the step of flattening being provided between the step of removing the second mask and the step of forming the second layer. The depth to which the polishing is performed in the step of flattening the top surfaces of the magnetic layer and the second nonmagnetic layer may fall within a range of 10 to 50 nm inclusive.

According to the method of the invention, the step of forming the first pole layer may include the steps of: forming a first mask for forming the first surface and the second surface of the first pole layer on the first pole layer; forming the first surface and the second surface by selectively etching a portion of the first pole layer through the use of the first mask; forming a first nonmagnetic layer so as to fill an etched portion of the first pole layer while the first mask is left unremoved; and removing the first mask after the first nonmagnetic layer is formed. The step of forming the second pole layer may include the steps of: forming a magnetic layer for forming the first layer on the gap layer; forming a second mask on the magnetic layer for forming an end portion of the magnetic layer opposite to the medium facing surface; forming the end portion of the magnetic layer by selectively etching the magnetic layer through the use of the second mask; forming a second nonmagnetic layer so as to fill an etched portion of the magnetic layer while the second mask is left unremoved; removing the second mask after the second nonmagnetic layer is formed; forming the second layer on the magnetic layer and the second nonmagnetic layer after the second mask is removed; and etching the magnetic layer to align with the width of the track width defining portion, so that the magnetic layer is formed into the first layer and that the width of each of the first layer and the second layer that is taken in the medium facing surface is made equal to the track width.

In this case, it is possible that the throat height is defined by the end portion of the first layer opposite to the medium facing surface and that the end portion of the first surface of the first pole layer opposite to the medium facing surface is located farther from the medium facing surface than the end portion of the first layer opposite to the medium facing surface.

The step of forming the first pole layer may further include the step of flattening the top surfaces of the first pole layer and the first nonmagnetic layer by polishing after the first mask is removed. The depth to which the polishing is performed in the step of flattening the top surfaces of the first pole layer and the first nonmagnetic layer may fall within a range of 10 to 50 nm inclusive. The step of forming the second pole layer may further include the step of flattening the top surfaces of the magnetic layer and the second nonmagnetic layer by polishing, the step of flattening being provided between the step of removing the second mask and the step of forming the second layer. The depth to which the polishing is performed in the step of flattening the top surfaces of the magnetic layer and the second nonmagnetic layer may fall within a range of 10 to 50 nm inclusive.

According to the invention, the cross-sectional area of each of the magnetic path of the first pole layer and the magnetic path of the second pole layer gradually changes in the neighborhood of the medium facing surface. Therefore, according to the invention, the overwrite property of the thin-film magnetic head is improved while the occurrences of side write and side erase are suppressed.

Other and further objects, features and advantages of the invention will appear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A and FIG. 1B are cross-sectional views for illustrating a step in a method of manufacturing a thin-film magnetic head of a first embodiment of the invention.

FIG. 2A and FIG. 2B are cross-sectional views for illustrating a step that follows FIG. 1A and FIG. 1B.

FIG. 3A and FIG. 3B are cross-sectional views for illustrating a step that follows FIG. 2A and FIG. 2B.

FIG. 4A and FIG. 4B are cross-sectional views for illustrating a step that follows FIG. 3A and FIG. 3B.

FIG. 5A and FIG. 5B are cross-sectional views for illustrating a step that follows FIG. 4A and FIG. 4B.

FIG. 6A and FIG. 6B are cross-sectional views for illustrating a step that follows FIG. 5A and FIG. 5B.

FIG. 7A and FIG. 7B are cross-sectional views for illustrating a step that follows FIG. 6A and FIG. 6B.

FIG. 8A and FIG. 8B are cross-sectional views for illustrating a step that follows FIG. 7A and FIG. 7B.

FIG. 9A and FIG. 9B are cross-sectional views for illustrating a step that follows FIG. 8A and FIG. 8B.

FIG. 10A and FIG. 10B are cross-sectional views for illustrating a step that follows FIG. 9A and FIG. 9B.

FIG. 11A and FIG. 11B are cross-sectional views for illustrating a step that follows FIG. 10A and FIG. 10B.

FIG. 12A and FIG. 12B are cross-sectional views for illustrating a step that follows FIG. 1A and FIG. 11B.

FIG. 13A and FIG. 13B are cross-sectional views for illustrating a step that follows FIG. 12A and FIG. 12B.

FIG. 14A and FIG. 14B are cross-sectional views for illustrating a step that follows FIG. 13A and FIG. 13B.

FIG. 15A and FIG. 15B are cross-sectional views for illustrating a step that follows FIG. 14A and FIG. 14B.

FIG. 16A and FIG. 16B are cross-sectional views for illustrating a step that follows FIG. 15A and FIG. 15B.

FIG. 17A and FIG. 17B are cross-sectional views for illustrating a step that follows FIG. 16A and FIG. 16B.

FIG. 18 is a plan view for illustrating the shape and arrangement of the thin-film coil of the thin-film magnetic head of the first embodiment of the invention.

FIG. 19 is a perspective view for illustrating the configuration of the thin-film magnetic head of the first embodiment.

FIG. 20A and FIG. 20B are cross-sectional views for illustrating a step in a modification example of the method of manufacturing the thin-film magnetic head of the first embodiment.

FIG. 21A and FIG. 21B are cross-sectional views for illustrating a step in a method of manufacturing a thin-film magnetic head of a second embodiment of the invention.

FIG. 22A and FIG. 22B are cross-sectional views for illustrating a step that follows FIG. 21A and FIG. 21B.

FIG. 23A and FIG. 23B are cross-sectional views for illustrating a step that follows FIG. 22A and FIG. 22B.

FIG. 24A and FIG. 24B are cross-sectional views for illustrating a step that follows FIG. 23A and FIG. 23B.

FIG. 25A and FIG. 25B are cross-sectional views for illustrating a step that follows FIG. 24A and FIG. 24B.

FIG. 26A and FIG. 26B are cross-sectional views for illustrating a step that follows FIG. 25A and FIG. 25B.

FIG. 27A and FIG. 27B are cross-sectional views for illustrating a step that follows FIG. 26A and FIG. 26B.

FIG. 28A and FIG. 28B are cross-sectional views for illustrating a step in a method of manufacturing a thin-film magnetic head of a third embodiment of the invention.

FIG. 29A and FIG. 29B are cross-sectional views for illustrating a step that follows FIG. 28A and FIG. 28B.

FIG. 30A and FIG. 30B are cross-sectional views for illustrating a step that follows FIG. 29A and FIG. 29B.

FIG. 31A and FIG. 31B are cross-sectional views for illustrating a step that follows FIG. 30A and FIG. 30B.

FIG. 32A and FIG. 32B are cross-sectional views for illustrating a step that follows FIG. 31A and FIG. 31B.

FIG. 33A and FIG. 33B are cross-sectional views for illustrating a step that follows FIG. 32A and FIG. 32B.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the invention will now be described in detail with reference to the accompanying drawings.

(First Embodiment)

Reference is now made to FIG. 1A to FIG. 17A, FIG. 1B to FIG. 17B, FIG. 18 and FIG. 19 to describe a method of manufacturing a thin-film magnetic head of a first embodiment of the invention. FIG. 1A to FIG. 17A are cross sections orthogonal to the air bearing surface and the top surface of a substrate. FIG. 1B to FIG. 17B are cross sections of magnetic pole portions each of which is parallel to the air bearing surface. FIG. 18 is a plan view showing the shape and arrangement of a thin-film coil of the thin-film magnetic head of the embodiment. FIG. 19 is a perspective view for illustrating the configuration of the thin-film magnetic head in which an overcoat layer is omitted.

In the method of manufacturing the thin-film magnetic head of the embodiment, a step shown in FIG. 1A and FIG. 1B is first performed. In the step an insulating layer 2 made of alumina (Al.sub.2O.sub.3), for example, is deposited to a thickness of approximately 1 to 3 .mu.m on a substrate 1 made of aluminum oxide and titanium carbide (Al.sub.2O.sub.3--TiC), for example. Next, a bottom shield layer 3 for a read head, made of a magnetic material such as Permalloy and having a thickness of approximately 2 to 3 .mu.m, is formed on the insulating layer 2. The bottom shield layer 3 is selectively formed on the insulating layer 2 by plating through the use of a photoresist film as a mask, for example. Although not shown, an insulating layer that is made of alumina, for example, and has a thickness of 3 to 4 .mu.m, for example, is formed over the entire surface. The insulating layer is then polished by chemical mechanical polishing (hereinafter referred to as CMP), for example, to expose the bottom shield layer 3 and to flatten the surface.

On the bottom shield layer 3, a bottom shield gap film 4 serving as an insulating film and having a thickness of approximately 20 to 40 nm, for example, is formed. On the bottom shield gap film 4, an MR element 5 for magnetic signal detection having a thickness of tens of nanometers is formed. For example, the MR element 5 may be formed by selectively etching an MR film formed by sputtering. The MR element 5 is located near a region in which the air bearing surface described later is to be formed. The MR element 5 may be an element made up of a magnetosensitive film that exhibits magnetoresistivity, such as an AMR element, a GMR element or a TMR (tunnel magnetoresistive) element. Next, although not shown, a pair of electrode layers, each having a thickness of tens of nanometers, to be electrically connected to the MR element 5 are formed on the bottom shield gap film 4. A top shield gap film 7 serving as an insulating film and having a thickness of approximately 20 to 40 nm, for example, is formed on the bottom shield gap film 4 and the MR element 5. The MR element 5 is embedded in the shield gap films 4 and 7. Examples of insulating materials used for the shield gap films 4 and 7 include alumina, aluminum nitride, and diamond-like carbon (DLC). The shield gap films 4 and 7 may be formed by sputtering or chemical vapor deposition (hereinafter referred to as CVD).

Next, a top shield layer 8 for a read head, made of a magnetic material and having a thickness of approximately 1.0 to 1.5 .mu.m, is selectively formed on the top shield gap film 7. Next, although not shown, an insulating layer made of alumina, for example, and having a thickness of 2 to 3 .mu.m, for example, is formed over the entire surface, and polished by CMP, for example, so that the top shield layer 8 is exposed, and the surface is flattened.

An insulating layer 9 made of alumina, for example, and having a thickness of approximately 0.3 .mu.m, for example, is formed over the entire top surface of the layered structure obtained through the foregoing steps. On the entire top surface of the insulating layer 9, a first layer 10a of the bottom pole layer 10 made of a magnetic material and having a thickness of approximately 0.5 to 1.0 .mu.m is formed. The first layer 10a has a top surface that is flat throughout. The bottom pole layer 10 includes the first layer 10a, and a second layer 10b, a third layer 10d, a fourth layer 10f, and coupling layers 10c, 10e and 10g that will be described later.

The first layer 10a may be formed by plating, using NiFe (80 weight % Ni and 20 weight % Fe), or a high saturation flux density material such as NiFe (45 weight % Ni and 55 weight % Fe), CoNiFe (10 weight % Co, 20 weight % Ni and 70 weight % Fe), or FeCo (67 weight % Fe and 33 weight % Co). Alternatively, the first layer 10a may be formed by sputtering, using a high saturation flux density material such as CoFeN, FeAlN, FeN, FeCo, or FeZrN. In this embodiment the first layer 10a is formed by sputtering to have a thickness of 0.5 to 1.0 .mu.m by way of example.

Next, an insulating film 11 made of alumina, for example, and having a thickness of 0.2 .mu.m, for example, is formed on the first layer 10a. The insulating film 11 is then selectively etched to form openings in the insulating film 11 in regions in which the second layer 10b and the coupling layer 10c are to be formed.

Next, although not shown, an electrode film of a conductive material having a thickness of 50 to 80 nm is formed by sputtering, for example, so as to cover the first layer 10a and the insulating film 11. This electrode film functions as an electrode and a seed layer for plating. Next, although not shown, a frame is formed on the electrode film by photolithography. The frame will be used for forming a first coil 13 by plating.

Next, electroplating is performed, using the electrode film, to form the first coil 13 made of a metal such as copper (Cu) and having a thickness of approximately 3.0 to 3.5 .mu.m. The first coil 13 is disposed in the region in which the insulating film 11 is located. Next, the frame is removed, and portions of the electrode film except the portion below the first coil 13 are then removed by ion beam etching, for example.

Next, although not shown, a frame is formed on the first layer 10a and the insulating film 11 by photolithography. The frame will be used for forming the second layer 10b and the coupling layer 10c of the bottom pole layer 10 by frame plating.

FIG. 2A and FIG. 2B illustrate the following step. In the step electroplating is performed to form the second layer 10b and the coupling layer 10c, each of which is made of a magnetic material and has a thickness of 3.5 to 4.0 .mu.m, for example, on the first layer 10a. For example, the second layer 10b and the coupling layer 10c may be made of NiFe, CoNiFe or FeCo. In the present embodiment the second layer 10b and the coupling layer 10c are made of CoNiFe having a saturation flux density of 1.9 to 2.3 tesla (T) by way of example. In the embodiment, when the second layer 10b and the coupling layer 10c are formed by plating, no specific electrode film is provided, but the unpatterned first layer 10a is used as an electrode and a seed layer for plating.

Next, although not shown, a photoresist layer is formed to cover the first coil 13, the second layer 10b and the coupling layer 10c. Using the photoresist layer as a mask, the first layer 10a is selectively etched by reactive ion etching or ion beam etching, for example. The first layer 10a is thus patterned. Next, the photoresist layer is removed.

FIG. 3A and FIG. 3B illustrate the following step. In the step an insulating layer 15 made of photoresist, for example, is formed in a region in which a second coil 19 described later is to be located. The insulating layer 15 is formed so that at least the space between the second layer 10b and the first coil 13, the space between the turns of the first coil 13, and the space between the coupling layer 10c and the first coil 13 are filled with the insulating layer 15. Next, an insulating layer 16 made of alumina, for example, and having a thickness of 4 to 6 .mu.m is formed so as to cover the insulating layer 15.

FIG. 4A and FIG. 4B illustrate the following step. In the step the 10b and the first coil 13, the groove between the turns of the first coil 13, and the groove between the coupling layer 10c and the first coil 13, but is intended to cover the grooves, taking advantage of good step coverage of CVD. The first and second conductive films in combination are called an electrode film. The electrode film functions as an electrode and a seed layer for plating. Next, on the electrode film, a conductive layer 19p made of a metal such as Cu and having a thickness of 3 to 4 .mu.m, for example, is formed by plating. The electrode film and the conductive layer 19p are used for making the second coil 19. The conductive layer 19p of Cu is formed through plating on the second conductive film of Cu formed by CVD, so that the second coil 19 is properly formed in the space between the second layer 10b and the first coil 13, the space between the turns of the first coil 13, and the space between the coupling layer 10c and the first coil 13.

FIG. 6A and FIG. 6B illustrate the following step. In the step the conductive layer 19p is polished by CMP, for example, so that the second layer 10b, the coupling layer 10c, and the first coil 13 are exposed. As a result, the second coil 19 is made up of the conductive layer 19p and the electrode film that remain in the space between the second layer 10b and the first coil 13, the space between the turns of the first coil 13, and the space between the coupling layer 10c and the first coil 13. The above-mentioned polishing is performed such that each of the second layer 10b, the coupling layer 10c, the first coil 13 and the second coil 19 has a thickness of 2.0 to 3.0 .mu.m, for example. The second coil 19 has turns at least part of which is disposed between turns of the first coil 13. The second coil 19 is formed such that only the insulating film 17 is provided between the turns of the first coil 13 and the turns of the second coil 19.

FIG. 18 illustrates the first coil 13 and the second coil 19. FIG. 6A is a cross section taken along line 6A--6A of FIG. 18. Connecting layers 21, 46 and 47, the top pole layer 30 and the air bearing surface 42 that will be formed later are shown in FIG. 18, too. As shown in FIG. 18, a connecting portion 13a is provided near an inner end of the first coil 13. A connecting portion 13b is provided near an outer end of the first coil 13. A connecting portion 19a is provided near an inner end of the second coil 19. A connecting portion 19b is provided near an outer end of the second coil 19.

In the step of forming the first coil 13 or the step of forming the second coil 19, two lead layers 44 and 45 are formed to be disposed outside the first layer 10a of the bottom pole layer 10, as shown in FIG. 18. The lead layers 44 and 45 have connecting portions 44a and 45a, respectively.

The connecting portions 13a and 19b are connected to each other through a connecting layer 21 that will be formed later. The connecting portions 44a and 13b are connected to each other through a connecting layer 46 that will be formed later. The connecting portions 19a and 45a are connected to each other through a connecting layer 47 that will be formed later.

FIG. 7A and FIG. 7B illustrate the following step. In the step an insulating film 20 made of alumina, for example, and having a thickness of 0.1 to 0.3 .mu.m is formed to cover the entire top surface of the layered structure. Etching is selectively performed on the insulating film 20 in the portions corresponding to the second layer 10b, the coupling layer 10c, the two connecting portions 13a and 13b of the first coil 13, the two connecting portions 19a and 19b of the second coil 19, the connecting portion 44a of the lead layer 44, and the connecting portion 45a of the lead layer 45. The insulating film 20 thus etched covers the top surfaces of the coils 13 and 19 except the two connecting portions 13a and 13b of the first coil 13 and the two connecting portions 19a and 19b of the second coil 19.

Next, the connecting layers 21, 46 and 47 of FIG. 18 are formed by frame plating, for example. The connecting layers 21, 46 and 47 are made of a metal such as Cu and each have a thickness of 0.8 to 1.5 .mu.m, for example.

Next, a third layer 10d is formed on the second layer 10b, and a coupling layer 10e is formed on the coupling layer 10c each by frame plating, for example. The third layer 10d and the coupling layer 10e may be made of NiFe, CoNiFe or FeCo, for example. In the embodiment the third layer 10d and the coupling layer 10e are made of CoNiFe having a saturation flux density of 1.9 to 2.3 T by way of example. The third layer 10d and the coupling layer 10e each have a thickness of 0.8 to 1.5 .mu.m, for example.

Next, an insulating film 22 made of alumina, for example, and having a thickness of 1 to 2 .mu.m is formed to cover the entire top surface of the layered structure. The insulating film 22 is then polished by CMP, for example. This polishing is performed such that the top surfaces of the third layer 10d, the coupling layer 10e, the connecting layers 21, 46 and 47, and the insulating film 22 are flattened and each of these layers has a thickness of 0.3 to 1.0 .mu.m.

Next, although not shown, a magnetic layer made of a magnetic material and having a thickness of 0.3 to 0.5 .mu.m is formed by sputtering, so as to cover the entire top surface of the layered structure. The magnetic layer may be made of a high saturation flux density material such as CoFeN, FeAlN, FeN, FeCo, or FeZrN. In the embodiment the magnetic layer is made of CoFeN having a saturation flux density of 2.4 T by way of example.

FIG. 8A and FIG. 8B illustrate the following step. In the step, on the magnetic layer, an etching mask 24a is formed in the portion corresponding to the third layer 10d, and an etching mask 24b is formed in the portion corresponding to the coupling layer 10e. Each of the etching masks 24a and 24b has an undercut so that the bottom surface is smaller than the top surface in order to facilitate lift-off that will be performed later. Such etching masks 24a and 24b may be formed by patterning a resist layer made up of two stacked organic films, for example.

Next, the magnetic layer is selectively etched by ion beam etching, for example, through the use of the etching masks 24a and 24b. The fourth layer 10f and the coupling layer 10g are thereby formed on the third layer 10d and the coupling layer 10e, respectively. The fourth layer 10f and the coupling layer 10g are made up of portions of the magnetic layer remaining under the etching masks 24a and 24b after the etching. This etching is performed such that the direction in which ion beams move forms an angle in a range of 0 to 20 degrees inclusive with respect to the direction orthogonal to the top surface of the first layer 10a. Next, to remove deposits on the sidewalls of the magnetic layer 23 after the etching, another etching is performed such that the direction in which ion beams move forms an angle in a range of 60 to 75 degrees inclusive with respect to the direction orthogonal to the top surface of the first layer 10a.

Next, an insulating layer 25 made of alumina, for example, and having a thickness of 0.4 to 0.6 .mu.m is formed so as to cover the entire top surface of the layered structure while the etching masks 24a and 24b are left unremoved. The insulating layer 25 is formed in a self-aligned manner so as to fill the etched portion of the above-mentioned magnetic layer. The etching insulating layers 15 and 16 are polished by CMP, for example, so that the second layer 10b, the coupling layer 10c and the insulating layer 15 are exposed, and the top surfaces of the second layer 10b, the coupling layer 10c and the insulating layers 15 and 16 (which is not shown in FIG. 4A and FIG. 4B) are flattened.

FIG. 5A and FIG. 5B illustrate the following step. In the step the insulating layer 15 is removed, and an insulating film 17 made of alumina, for example, is then formed by CVD, for example, so as to cover the entire top surface of the layered structure. As a result, grooves covered with the insulating film 17 are formed in the space between the second layer 10b and the first coil 13, the space between the turns of the first coil 13, and the space between the coupling layer 10c and the first coil 13. The insulating film 17 has a thickness of 0.08 to 0.15 .mu.m, for example. The insulating film 17 may be formed by CVD, for example, wherein a gas of H.sub.2O, N.sub.2O, H.sub.2O.sub.2 or O.sub.3 (ozone) as a material used for making thin films and Al(CH.sub.3).sub.3 or AlCl.sub.3 as a material used for making thin films are alternately ejected in an intermittent manner under a reduced pressure at a temperature of 180 to 220.degree. C. Through this method, a plurality of thin alumina films are stacked so that the insulating film 17 that is closely-packed and exhibits a good step coverage, and has a desired thickness is formed.

Next, a first conductive film made of Cu, for example, and having a thickness of 50 nm, for example, is formed by sputtering so as to cover the entire top surface of the layered structure. On the first conductive film, a second conductive film made of Cu, for example, and having a thickness of 50 nm, for example, is formed by CVD. The second conductive film is not intended to be used for entirely filling the groove between the second layer masks 24a and 24b are then lifted off. Next, CMP is performed for a short period of time, for example, to polish and flatten the top surfaces of the fourth layer 10f, the coupling layer 10g and the insulating layer 25. This flattening removes small differences in levels between the fourth layer 10f and the insulating layer 25, and between the coupling layer 10g and the insulating l