JP2010086572A - Method for manufacturing magnetic head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently manufacture a reliable magnetic head. <P>SOLUTION: When forming a main magnetic pole of the magnetic head, a plated underlayer 31 is formed on a substrate 1. A magnetic film 32, a hard mask formed of mask layers 33 to 35, and a photoresist film 37 are laminated on the plated underlayer 31, and the magnetic film 32 is etched using them. After that, a photoresist film 41 is formed, and an opening 42 is provided, and thereafter tapered by reflow treatment. Using the tapered opening, a sacrifice layer 45 is deposited by a plating method, and the photoresist film 41 is removed. Thereafter, an ion beam is applied obliquely to process the sacrifice layer 45 and the magnetic film 32. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a magnetic head of a magnetic recording apparatus that reads and writes magnetic data.

  Among various recording devices used in computers, audios, and the like, magnetic recording devices have been used historically and have been widely used. As one of the magnetic recording apparatuses, there is a magnetic disk apparatus having a disk-shaped magnetic recording medium and a magnetic head that floats thereon.

  Most of the recording methods of the magnetic disk apparatus supplied to the market so far are called in-plane magnetic recording methods in which the direction of magnetization recorded on the recording layer is in the plane direction. In order to obtain a high recording density in this in-plane magnetic recording system, it is necessary to make the recording layer of the magnetic recording medium thin and make the magnetic crystal grains constituting the recording layer fine.

However, if the recording layer of the magnetic recording medium is thinned, a phenomenon that information is lost when heat is applied to the magnetic disk, that is, a thermal fluctuation phenomenon occurs, which is one factor that hinders an increase in recording density.
On the other hand, there is a perpendicular magnetic recording method in which the direction of magnetization in the recording layer is directed to the direction perpendicular to the surface of the recording layer, which has been put into practical use in recent years.

  The perpendicular magnetic recording method can reduce the area of each magnetic domain on the surface of the recording layer as compared with the in-plane magnetic recording method. For this reason, it is possible to achieve a higher recording density. Furthermore, since the recording magnetization is oriented in the direction perpendicular to the film surface of the recording layer, the occurrence of the thermal fluctuation phenomenon that occurs when the recording layer is thinned is prevented, and there is no inconvenience caused by increasing the thickness of the recording layer. .

In the perpendicular magnetic recording system, the tip of the main pole is formed in an inverted trapezoidal shape in order to achieve high-density recording and to suppress the side erase effect. In the main pole forming method using the conventional ion milling method, a non-magnetic material is previously laminated on the magnetic film to form a mask with a relatively slow etching rate, and the magnetic film is etched vertically using this mask. The basic pattern of the main pole was formed. At this time, the ion irradiation angle was set to 35 ° to 45 ° so that an etching product containing a magnetic material generated when the magnetic film was etched did not adhere to the side wall of the magnetic film. Next, the angle of the ion beam is changed, and a predetermined taper is provided on the side of the magnetic film so as to form an inverted trapezoid. The incident angle of the ion beam at this time was set to about 40 ° to 70 ° with respect to the normal direction of the substrate surface. (For example, see Patent Documents 1, 2, and 3)
JP 2005-42143 A Japanese Patent Laid-Open No. 2006-114076 JP 2007-184036 A

However, in the conventional manufacturing method, the etching amount in the width direction of the magnetic film is large, and the dimensional change (shift amount) before and after processing is large. If the dimensional change of the magnetic film during ion milling becomes large, dimensional errors in the width direction of the final pattern are likely to occur, or variations in the shape of each main pole in the substrate plane when a large number of main poles are formed on one substrate Is likely to occur.
The present invention has been made in view of such circumstances, and has as its main object to efficiently manufacture a highly reliable magnetic head.

  According to one aspect of the present application, a step of forming a magnetic film over a substrate, a step of laminating a mask layer on the magnetic film, a step of etching the magnetic film using the mask layer, and the magnetic A step of forming a sacrificial layer covering the side of the film; and a step of processing the sacrificial layer and the magnetic film by irradiating an ion beam from a direction intersecting a normal line of the substrate surface. A manufacturing method of the magnetic head was adopted.

  According to the present invention, after the magnetic film is patterned, the sacrificial layer and the magnetic film are processed with an ion beam so that the magnetic film can be easily formed into a desired tapered shape while reducing the processing amount of the magnetic film. Become. Therefore, shaping with an ion beam can be easily performed using a sacrificial layer, and the shift amount of the magnetic film can be suppressed, so that variations during processing can be prevented and a highly reliable magnetic head can be manufactured.

Embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a magnetic head according to an embodiment of the present invention. The magnetic head has a structure applied to, for example, a perpendicular magnetic recording system, and is made of a substrate 1 made of a nonmagnetic material such as AlTiC (Al ₂ O ₃ —TiC) and an insulating material such as alumina (Al ₂ O ₃ ). The magnetic reproducing head 10 is formed on the substrate 1 via the layer 2, and the magnetic recording head 20 is formed on the magnetic reproducing head 10 via the insulating separation layer 3 such as alumina.

  The nonmagnetic substrate 1 is processed into a slider shape by cutting, polishing or the like after the magnetic head is formed. After the slider processing, the magnetic head composed of the magnetic reproducing head 10 and the magnetic recording head 20 is disposed to face the recording surface of the magnetic recording medium 5.

On the substrate 1, the magnetic reproducing head 10 is disposed on the leading side with respect to the magnetic recording medium 5, and the magnetic recording head 20 is disposed on the trailing side.
The magnetic reproducing head 10 includes a lower magnetic shield layer 11, an insulating gap layer 12, and an upper magnetic shield layer 14 formed in order on the insulating layer 2, and a reproducing element 13 is formed in the insulating gap layer 12. Has been.

  The lower magnetic shield layer 11 and the upper magnetic shield layer 14 are made of a magnetic material, for example, an FeNi (for example, Fe: 20 mass%, Ni: 80 mass%) alloy layer. The insulating gap layer 12 is made of an insulating material such as alumina. The reproducing element 13 is connected to a pair of electrodes (not shown) formed in the insulating gap layer 12. Depending on the element structure, the lower and upper magnetic shield layers 11 and 14 are also used as a pair of electrodes. Sometimes.

As the reproducing element 13, for example, a magnetoresistive (MR) effect element, a giant magnetoresistance (GMR) effect element, or a tunneling magnetoresistance (TMR) effect element is formed.
The reproducing element 13 is formed in a region that becomes an air bearing surface (ABS surface) of the magnetic head with respect to the magnetic recording medium 5, that is, a medium facing surface.

  In the magnetic recording head 20, a main magnetic pole 21 is formed on the insulating separation layer 3, and a nonmagnetic gap layer 23 is provided on the main magnetic pole 21. Further, a planarization insulating layer 22 is formed around the main magnetic pole 21 and the nonmagnetic gap layer 23, and a base insulating layer 24 a is provided on the nonmagnetic gap layer 23 and the planarization insulating layer 22. .

  An exciting coil 25 is formed on the base insulating layer 24a, and the exciting coil 25 is covered with a covering insulating layer 24b. A return yoke 26 made of a magnetic film is provided on the trailing side of the covering insulating layer 24b. A trading-side magnetic shield layer 27 is connected to the tip of the return yoke 26 on the medium facing surface side. A trading-side magnetic shield layer 27 is provided close to the main magnetic pole 21 formed on the nonmagnetic gap layer 23. Further, the magnetic recording head 20 is also provided with a side magnetic shield (not shown) and the like that are arranged close to the cross track side of the main magnetic pole 21.

The magnetic recording head 20 has a structure in which an excitation coil and a return yoke are arranged not only on the trailing side of the main magnetic pole 21 but also on the leading side.
As shown in the perspective view of FIG. 2, the main magnetic pole 21 includes a rectangular yoke portion 21a, a tapered diaphragm (flare) section 21b protruding from the yoke section 21a toward the ABS surface (medium facing surface), and a diaphragm section. It is comprised from the striped front-end | tip part 21c which protrudes from the front-end | tip on the ABS surface side among 21b.

  The yoke portion 21 a of the main magnetic pole 21 is magnetically connected to the return yoke 26 through a contact hole 28 formed through a substantially central gap of the exciting coil 25. The upper surface of the tip 21c has a planar shape with a width of 50 nm to 120 nm and a length of 200 nm to 250 nm, for example.

Next, the process of forming the main magnetic pole 21 will be described with reference to FIGS. 3A to 3I. 3A to 3I are cross-sectional views of the forming process as seen from the line II in FIG.
First, steps required until a sectional structure shown in FIG.
First, a nonmagnetic plating base layer 31 is formed on the substrate 1 by sputtering. As shown in FIG. 1, an insulating layer 2, a magnetic reproducing head 10, an insulating separation layer 3 and the like are usually formed between the substrate 1 and the plating base layer 31, but here these are formed. A description of the process is omitted. For the plating base layer 31, Ta, Ru, or the like is used. When Ta is used, the crystallinity of the magnetic material layer to be formed next is improved.

A magnetic film 32 to be the main magnetic pole 21 is formed on the plating base layer 31. The magnetic film 32 is made of, for example, FeCo, and is formed to a predetermined thickness, for example, 200 nm to 250 nm by a sputtering method. Further, a first mask layer 33 made of a nonmagnetic material such as Al ₂ O _{3 is formed} on the magnetic film 32 by sputtering, for example, to a thickness of 700 nm to 800 nm. The first mask layer 33 is preferably made of a material that can make the etching rate smaller than that of the magnetic film 32.

  Here, as the magnetic film 32, for example, an FeCo layer containing 70% by mass of iron (Fe) and 30% by mass of cobalt (Co) is formed. As the magnetic film 32, a multilayer structure in which a plurality of high saturation magnetic flux density layers and antiferromagnetic layers are alternately formed by sputtering may be employed. For example, FeCo, iron / cobalt / nickel (FeCoNi) or the like is adopted as the high saturation magnetic flux density layer in the multilayer structure, and chromium (Cr) is adopted as the antiferromagnetic material layer. Further, a nonmagnetic layer such as alumina or ruthenium may be formed instead of the antiferromagnetic material layer. The magnetic film 32 has better magnetic properties when formed by a PVD method such as a sputtering method than when formed by a plating method.

  Further, a second mask layer 34 made of NiFe or the like is formed on the first mask layer 33. The second mask layer 34 is made of a material that can have an etching rate lower than that of the first mask layer 33, and is formed to have a film thickness sufficient for etching the first mask layer 33, for example, 100 nm to 150 nm.

  Next, a third mask layer 35 made of Ta or the like is formed on the second mask layer 34. The third mask layer 35 is made of a material whose etching rate can be made smaller than that of the second mask layer 34, and is formed to a thickness sufficient for etching the second mask layer 34, for example, 50 nm to 100 nm.

  Further, a photoresist film 37 is applied on the third mask layer 35 by a spin coat method or the like. The photoresist film is formed to a thickness sufficient for etching the third mask layer 35. Note that the photoresist film 37 is patterned in accordance with the planar shape of the main pole 21 by lithography.

  Thus, after forming the hard mask having the laminated structure of the first mask layer 33, the second mask layer 34, and the third mask layer 35, and the photoresist film 37, the RIE (not shown) is illustrated. The substrate 1 is carried into the chamber of the reactive ion etching apparatus and etching is performed.

First, as shown in FIG. 3B, a high frequency is applied to the electrode while supplying CF ₄ gas into the chamber, and the third mask layer 35 is etched using the photoresist film 37 as a mask. In this etching, the portion of the third mask layer 35 not covered with the photoresist film 37 is etched to expose the underlying second mask layer 34. As a result, the third mask layer 35 is left as a pattern substantially corresponding to the shape of the main magnetic pole 21.

Next, the gas supplied into the chamber is switched to CH ₃ OH gas, and the second mask layer 34 is etched using the third mask layer 35 as a mask. As shown in FIG. 3C, in this etching, the portion of the second mask layer 34 that is not covered with the third mask layer 35 is etched to expose the underlying first mask layer 33. As a result, the second mask layer 34 is left as a pattern substantially corresponding to the shape of the main magnetic pole 21.

Further, the gas supplied into the chamber is switched to BCl ₃ gas, and the first mask layer 33 is etched using the second mask layer 34 as a mask. As shown in FIG. 3D, the portion of the first mask layer 33 not covered with the second mask layer 34 is etched to expose the underlying magnetic film. As a result, at least the first mask layer 33 is left as a pattern substantially corresponding to the shape of the main magnetic pole 21. The first, second and third mask layers 33 to 35 may be etched by different chambers.

  After removing the substrate 1 from the RIE apparatus, the substrate 1 is carried into an ion milling apparatus. Then, as shown by an arrow in FIG. 3E, the ion beam is made substantially parallel to the normal of the substrate surface, that is, directly incident, and the magnetic film 32 is etched using the first mask layer 33 as a mask. When the portion of the magnetic film 32 not covered with the first mask layer 33 is etched and the plating base layer 31 is exposed, the etching is finished. As a result, the magnetic film 32 is left as a pattern substantially corresponding to the shape of the main magnetic pole 21. In order to prevent the etching product from adhering to the side surface of the pattern of the magnetic film 32, the ion beam may be irradiated from the direction intersecting the normal direction of the substrate surface.

Next, steps required until a sectional structure shown in FIG.
The substrate 1 is once taken out from the ion milling apparatus, and a photoresist film 41 is formed on the entire surface by a spin coating method. The photoresist film 41 is formed with an opening 42 having a predetermined shape and a space of a predetermined size around the pattern of the main magnetic pole 21 by a lithography technique. That is, the magnetic film 32, the first mask layer 33, and the plating base layer 31 around the magnetic film 32 are exposed from the opening 42 of the photoresist film 41. The opening 42 of the photoresist film 41 has a shape exposing at least the tip 21C of the main magnetic pole 21 and its periphery as shown in FIG.

  After patterning the photoresist film 41, the substrate 1 is carried into a reflow furnace (not shown), and the photoresist film 41 is heated. As a result, the photoresist film 41 is thermally contracted, and the side wall of the opening 42 is inclined with a predetermined taper angle α with respect to the normal line of the substrate surface. The taper angle α is preferably 10 ° to 15 ° corresponding to the taper angle of the main magnetic pole 21. The taper angle α of the side wall of the opening 42 can be controlled by the reflow temperature. For example, when heated at 154 ° C. for 300 seconds, it can be tilted by 10 ° with respect to the normal of the substrate surface.

  Thereafter, as shown in FIG. 3G, a sacrificial layer 45 is deposited on the plating base layer 31 exposed from the photoresist film 41 by electrolytic plating. For the sacrificial layer 45, for example, a material having a milling rate similar to that of the magnetic pole film 32 at the time of ion milling, such as NiFe, FeCo, or Cr, is used.

  Next, as shown in FIG. 3H, when the photoresist film 37 is removed, the sacrificial layer 45 having a reverse taper remains on both side portions 32A of the tip portion 21C of the magnetic pole film 32. That is, the sacrificial layers 45 are arranged one by one on the left and right sides with the magnetic film 32 in between, and the whole becomes an inverted trapezoid. A side wall 45A corresponding to an end portion in the arrangement direction (width direction) of each sacrificial layer 45 is inclined in accordance with the taper angle α of the photoresist film 41. The length of the upper surface of each sacrificial layer 45 in the width direction is preferably 20 nm to 50 nm, for example. If the length in the width direction of the sacrificial layer 45 is larger than this, it takes too much time for ion milling of the magnetic film 32 to be performed later. If the length of the sacrificial layer 45 in the width direction is shorter than this, the etching amount (shift amount) of the magnetic film 32 becomes large. In the present embodiment, the width of the sacrificial layer 45 is described as being thicker than the actual value for easy understanding. As described above, since the magnetic pole film 32 is formed to a thickness of, for example, 200 nm to 250 nm by sputtering, the thickness (height) of the sacrificial layer 45 in FIG. 3H is similarly 200 nm to 250 nm. Degree. On the other hand, the width of the sacrificial layer 45 in FIG. 3H is, for example, 20 nm to 50 nm, and when accurately depicted, the width of the sacrificial layer 45 is actually thinner than that illustrated in FIG. 3H.

Next, steps required until a sectional structure shown in FIG.
The substrate 1 is carried into the etching apparatus, and the sacrificial layer 45 and the magnetic film 32 are irradiated with an ion beam. The ion beam irradiation angle β is an angle with respect to the normal of the substrate surface, that is, a normal incidence angle of 60 ° to 80 °, more preferably about 70 °. At this time, since the side portion 32A of the magnetic film 32 is covered with the sacrificial layer 45, only the sacrificial layer 45 is gradually processed without processing the magnetic film 32 in the initial stage. Note that the first mask layer 33 that is not irradiated with the ion beam is not processed.

  Since the side wall 45A of the sacrificial layer 45 that is incident with the ion beam inclined and is exposed to the ion beam has a reverse taper shape, the substrate 1 side of the sacrificial layer 45 is removed first. Then, from the point where the sacrificial layer 45 is removed, the magnetic film 32 is gradually processed by the ion beam. In other words, when the processing of the magnetic film 32 on the substrate 1 side is started, the sacrificial layer 45 still remains on the first mask layer 33 side, and the magnetic film 32 in this region is not processed.

  Here, when the ion beam is incident at an angle of about 60 ° to 80 °, the substrate side of the side wall 45A is scraped off slightly on the side opposite to the substrate 1 side (first mask layer 33 side). This is presumably because the concentration of the ion beam on the substrate 1 side increases due to factors such as reflection of the ion beam on the substrate 1 side of the side wall 45A from the substrate 1.

  As a result, the magnetic film 32 is processed on the substrate 1 side more than the first mask layer 33 side, and the width of the portion on the substrate 1 side becomes smaller. As a result, the magnetic film 32 becomes the main magnetic pole 21 as shown in FIG. That is, the main magnetic pole 21 having the tip portion 21C having a reverse tapered shape is formed. The angle γ of the side surface 21D of the main magnetic pole 21 is about 10 ° to 15 ° with respect to the normal line of the substrate surface. The cross-sectional shape of the tip 21C of the main pole 21 is not limited to an inverted trapezoid, and may be an inverted triangle, for example.

Next, steps required until a sectional structure shown in FIG.
First, a planarization insulating layer 22 made of a nonmagnetic material is deposited by sputtering or the like so as to cover the plating base layer 31, the main magnetic pole 21, and the first mask layer 33. After the planarization insulating layer 22 is deposited, the surface is planarized by polishing again by the CMP method.

Thereafter, a nonmagnetic gap layer 23 made of alumina is formed on the main magnetic pole 21 and the planarizing insulating layer 22 by sputtering.
Next, the base insulating film 24a, the exciting coil 25, the clothing insulating layer 24b, the return yoke 26, and the like shown in FIG. 1 are formed on the planarizing insulating layer 22 and the nonmagnetic gap layer 23, whereby the magnetic head wafer is formed. To complete.

As described above, in the manufacturing method according to the present embodiment, the sacrificial layer 45 having a reverse taper is provided so as to cover the surface of the magnetic film 32 to be processed, and the sacrificial layer 45 is first formed by ion milling. Since the etching is performed, the magnetic film 32 can be formed into a desired shape by a minimum processing. In particular, by making the object to be irradiated with the ion beam into a reverse taper shape in advance, the processing becomes easier. For this reason, the difference in the in-plane distribution can be increased, and variations between the substrates 1 can be prevented.
For example, in the conventional method, when the width of the main magnetic pole 21 is set to 100 nm, the width of the magnetic film and the first mask layer before ion milling must be set to about 180 nm. On the other hand, in the manufacturing method according to the present embodiment, the widths of the magnetic film 32 and the first mask layer 33 before ion milling can be made the same as the width required for the main magnetic pole 21.

  Further, in the manufacturing method according to the present embodiment, the patterning shape defect caused by the first ion milling can be corrected by the sacrificial layer 45, so that the patterning accuracy after the second ion milling can be improved.

The configuration of the hard mask for etching the magnetic film 32 is not limited to the embodiment.
The sacrificial layer 45 can also be formed by sputtering instead of being deposited by plating. In this case, the plating base layer is unnecessary. Further, the sacrificial layer 45 may have a side wall substantially perpendicular to the substrate surface without having an inversely tapered shape. The milling rate of the sacrificial layer 45 may be different from the milling rate of the magnetic film 32.

(Additional remark 1) The process of forming a magnetic film above a board | substrate, The process of laminating | stacking a mask layer on the said magnetic film, The process of etching the said magnetic film using the said mask layer, The side part of the said magnetic film A step of forming a sacrificial layer covering the substrate, and a step of irradiating an ion beam from a direction intersecting a normal line of the substrate surface to process the sacrificial layer and the magnetic film. Method.
(Supplementary note 2) The magnetic head manufacturing method according to supplementary note 1, wherein the sacrificial layer is formed of a material having a milling rate substantially the same as that of the magnetic film.
(Supplementary note 3) The method of manufacturing a magnetic head according to supplementary note 1 or supplementary note 2, wherein the sacrificial layer has an inverse tapered shape in which a width on the substrate side is narrowed.
(Supplementary Note 4) A plating underlayer is provided between the substrate and the magnetic film, the resist film is applied after etching the magnetic film using the mask layer, and the magnetic layer is exposed to the resist film. 4. The method of manufacturing a magnetic head according to appendix 3, wherein an opening having a wide upper side is formed, and a sacrificial layer is deposited on the opening by plating.
(Additional remark 5) After forming the said opening part in the said resist film, the said resist film is heated, the side wall of the said opening part is inclined, and it is set as the reverse taper shape which the width | variety of the said opening part at the said substrate side becomes narrow. The method of manufacturing a magnetic head according to appendix 4, wherein:
(Additional remark 6) The manufacturing method of the magnetic head of Additional remark 5 characterized by making the inclination-angle of the side wall of the said opening part of the said resist film into 10 degrees-15 degrees with respect to the normal line of a substrate surface.
(Supplementary note 7) The method of manufacturing a magnetic head according to any one of supplementary notes 1 to 6, wherein the plating base layer is a nonmagnetic conductive film.
(Supplementary note 8) The method of manufacturing a magnetic head according to any one of supplementary notes 1 to 7, wherein the sacrificial layer is formed of any material of NiFe, FeCo, and Cr.
(Additional remark 9) The said plating base layer is formed from Ta or Ru, The manufacturing method of the magnetic head of Additional remark 4 characterized by the above-mentioned.
(Supplementary Note 10) The magnetic head manufacturing method according to any one of Supplementary notes 1 to 9, wherein an irradiation angle of the ion beam when processing the magnetic film is 60 ° to 80 °.

FIG. 1 is a cross-sectional view showing a magnetic head according to an embodiment of the present invention. FIG. 2 is a perspective view showing the main pole applied to the magnetic recording head in the magnetic head according to the embodiment of the present invention. 3A is a cross-sectional view (No. 1) showing a manufacturing process for obtaining a cross-sectional structure taken along the line II of FIG. FIG. 3B is a sectional view (No. 2) showing the manufacturing process for obtaining the sectional structure taken along the line II of FIG. FIG. 3C is a cross-sectional view (part 3) illustrating the manufacturing process for obtaining a cross-sectional structure taken along the line II of FIG. 2. FIG. 3D is a cross-sectional view (part 4) illustrating the manufacturing process for obtaining a cross-sectional structure taken along the line II of FIG. FIG. 3E is a sectional view (No. 5) showing a manufacturing step for obtaining a sectional structure taken along the line II of FIG. FIG. 3F is a sectional view (No. 6) showing the manufacturing process for obtaining the sectional structure taken along the line II of FIG. FIG. 3G is a sectional view (No. 7) showing the manufacturing process for obtaining the sectional structure taken along the line II of FIG. FIG. 3H is a sectional view (No. 8) showing a manufacturing step for obtaining a sectional structure taken along the line II of FIG. FIG. 3I is a sectional view (No. 9) showing a manufacturing step for obtaining a sectional structure taken along the line II of FIG. FIG. 3J is a sectional view (No. 10) showing a manufacturing step for obtaining a sectional structure taken along line II in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 21 Main pole 31 Plating underlayer 32 Magnetic film 33 First mask layer 34 Second mask layer 35 Third mask layer 37 Photoresist layer 41 Photoresist layer 42 Opening 45 Sacrificial layer

Claims (5)

Forming a magnetic film above the substrate;
Laminating a mask layer on the magnetic film;
Etching the magnetic film using the mask layer;
Forming a sacrificial layer covering the side of the magnetic film;
Irradiating an ion beam from a direction intersecting the normal of the substrate surface, and processing the sacrificial layer and the magnetic film;
A method of manufacturing a magnetic head, comprising:   2. The method of manufacturing a magnetic head according to claim 1, wherein the sacrificial layer is formed of a material having substantially the same milling rate as the magnetic film.   3. The method of manufacturing a magnetic head according to claim 1, wherein the sacrificial layer has an inversely tapered shape in which a width on the substrate side is narrowed.   A plating underlayer is provided between the substrate and the magnetic film, the resist film is applied after etching the magnetic film using the mask layer, and the upper side is widened so that the magnetic layer is exposed to the resist film. 4. The method of manufacturing a magnetic head according to claim 3, wherein an opening is formed and a sacrificial layer is deposited on the opening by plating.   The method of manufacturing a magnetic head according to claim 1, wherein the plating base layer is a nonmagnetic conductive film.

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