JPH11232611A - Thin-film magnetic head and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin-film magnetic head having the low DC resistance of a coil without changing head performance and a head shape and without increasing a manufacturing process. SOLUTION: The thin-film magnetic head has a lower core 4, an upper core 12, an etching stop layer 16 formed to at least a part of the lower core 4, a coil-shaped groove section, in which a part is passed through an internal region between the lower core 4 and the upper core 12 and which is formed to insulating layers 5, 2 by etching so as to reach the etching stop layer 16 in an internal region layer and reach to a lower section from the top face of the lower core 4 on the outside of the internal region, and a coil 7 formed by filling the groove section with a conductive material. The coil 7 is insulated from the lower core 4 by the etching stop layer 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin-film magnetic head used in a magnetic recording / reproducing apparatus, and more particularly to a thin-film magnetic head in which the resistance of a thin-film coil is reduced.

[0002]

2. Description of the Related Art A magnetic recording / reproducing apparatus capable of easily recording an information signal on a recording medium and reproducing the information signal from the recording medium is provided with information signal recording / reproducing means in many technical fields. Has been adopted as.

In this magnetic recording / reproducing apparatus, in recent years,
Demands for high-density recording have increased, and thin-film magnetic heads have been adopted to meet such demands. The thin-film magnetic head is a head formed by sequentially laminating a lower core, an insulating layer, a coil, an insulating layer, an upper core, and the like on a nonmagnetic substrate by using photolithography and various film forming techniques. A practical example of such a thin-film magnetic head is, for example, a floating magnetic head in a fixed disk drive (HDD). There is also an attempt to use a thin film magnetic head as a rotary magnetic head for a VTR.

In general, in an induction type magnetic head, it is necessary to increase the number of turns of a coil in order to obtain a high output. The coil in the thin film magnetic head is formed by forming a thin film made of a conductive material into a spiral coil pattern. This coil pattern is formed around a connecting portion (intermediate core) between the lower core and the upper core. Therefore, a part of the coil is formed in a limited space between the lower core and the upper core, so that the number of turns of the coil cannot be increased without limit.

[0005] In a thin-film coil, when the winding width is increased, the coil resistance is reduced, but the head efficiency is reduced because the magnetic path length is increased. Conversely, reducing the coil winding width improves the head efficiency but increases the coil resistance. The magnetic path length is defined as the front magnetic gap between the front intermediate core disposed at the front of the thin-film magnetic head and the lower core, and the rear intermediate core disposed at the rear of the magnetic head. It refers to the distance between the lower magnetic core and the rear magnetic gap.

The characteristics required for a thin-film magnetic head differ depending on the purpose of the head. For example,
In a VTR, a magnetic head that satisfies various demands such as high quality of recorded / reproduced images and realization of high density recording / reproducing is required.

In a VTR, a magnetic head is used as a rotary head. To this end, the magnetic head transmits and receives signals to and from the electric circuit of the VTR via a rotary transformer.
There is a close relationship between the cutoff frequency of a signal that can be transmitted and the DC resistance of the magnetic head. FIG. 7 is a diagram showing an equivalent circuit (a) of the head rotary transformer and a relationship (b) between the low-frequency cutoff frequency and the DC resistance in the equivalent circuit. As can be seen from FIG. 7, as the DC resistance of the head increases, the lower cutoff frequency of the transmission signal increases in proportion thereto. The increase in the cutoff frequency causes a sag (distortion of a rectangular wave whose waveform apex is inclined to attenuate) in a waveform at the time of signal recording, thereby deteriorating the quality of a recorded signal. For this reason, the thin film magnetic head for the VTR is required to suppress the DC resistance of the thin film coil to be low and to improve the transmission characteristic of the low frequency band signal via the rotary transformer, unlike the thin film magnetic head for the HDD. . For example, if the cutoff frequency is set to 140 kHz or less under the conditions shown in FIG. 7, the DC resistance of the magnetic head must be set to an extremely low value of 3.8 Ω or less.

Generally, a thin film coil of a thin film magnetic head is
The cross-sectional area is smaller than that of a coil formed by winding a wire used in a conventional bulkhead. For this reason, the thin film coil generally has a high resistance value, which causes impedance noise. As described above, the thin-film coil is formed on a plane so as to be spirally wound around the rear magnetic gap of the thin-film magnetic head. In such a thin film coil, if the space for winding the coil is increased and the width or thickness of the coil is increased, the cross-sectional area is increased, and the resistance can be reduced.

However, the space width around which the coil is wound is limited in view of the performance of the head. For example, when the coil winding width is increased or the coil thickness is increased, the coil resistance is reduced, but the magnetic path length in the magnetic head is increased, and the head efficiency is reduced. Conversely, if the coil winding width is reduced or the coil thickness is increased,
The head efficiency improves, but the coil resistance increases.

That is, the width of the coil is limited by the distance between the front intermediate core and the rear intermediate core of the magnetic head,
Since the thickness of the coil is limited by the distance between the lower core upper surface and the upper core lower surface of the magnetic head, the resistance of the conventional thin-film coil can be suppressed to a lower level to some extent in consideration of head performance and head shape. It was difficult.

In order to solve the above-mentioned problem in the thin-film magnetic head, the present applicant has disclosed a thin-film magnetic head having a novel structure in Japanese Patent Application Laid-Open No. 7-272217. FIG.
8 is a diagram showing a thin film magnetic head disclosed in Japanese Patent Application Laid-Open No. 7-272217, FIG. 8A shows an outline of the thin film magnetic head, and FIG. Particularly, a portion including a core portion and a coil pattern is shown.
In FIG. 8, the direction indicated by the arrow is forward of the magnetic head.

As shown in FIG. 8, the thin film magnetic head has three insulating layers 2, 5 and 11 laminated on a substrate 1. A lower core 4 made of a soft magnetic material is arranged in the insulating layer 2, and an upper core 12 also made of the soft magnetic material is arranged in the insulating layer 11 so as to face the lower core 4. Have been. Intermediate cores 9a and 9b are arranged between the lower core 4 and the upper core 12, and form a kind of ring shape together with the upper core 12 and the lower core 4. A gap layer G made of an insulating layer is formed between the intermediate core 9a and the lower core 4 arranged on the front side of the head. Also, around the intermediate core 9b,
The coil conductor 7 is wound. Now, if the area between the upper core 12 and the lower core 4 is called an internal area and the other area is called an external area, the coil thickness of the coil conductor 7 is smaller than the distance between the upper core and the lower core in the internal area. In the outer region, it is larger. In the thin-film magnetic head disclosed in JP-A-7-272217 having such a configuration, since the cross-section of the thin-film coil in the outer region is larger than that in the inner region, the DC resistance of the coil is smaller than before. The effect has been obtained.

FIGS. 9 to 12 show Japanese Patent Application Laid-Open No. 7-272.
217 is a view illustrating a process of manufacturing the thin-film magnetic head disclosed in No. 217. In FIGS. 9 to 12, (A)
The one marked with is a sectional view of the thin-film magnetic head, the one marked with (B) is a partial plan view, and the left side of the paper is the front of the magnetic head. The method of manufacturing a thin film head disclosed in Japanese Patent Application Laid-Open No. 7-272217 will be briefly described below with reference to FIG.

First, a lower core 4 made of a soft magnetic material is formed on a substrate 1, and an insulating layer 2 is formed around the lower core 4 (FIG. 9A). Next, a spiral groove 7b is formed in the insulating layer 2, and a conductor film is formed in the groove 7b (FIG. 9B). The formed conductor film is on the lower layer side of the coil conductor 7. Next, the nonmagnetic layer 8 is formed on a part of the upper surface of the lower core 4, and the intermediate core 9a is further formed thereon. Here, the nonmagnetic layer 8 is a layer that becomes a magnetic gap G between the intermediate core 9a and the lower core 4. Also, the intermediate core 9b is connected to the lower core 4 at a position opposite to the side on which the intermediate core 9a is formed.
Formed on the upper surface of the substrate. Further, an insulating layer 5 is formed in other portions except for the intermediate cores 9a and 9b.
(A)).

Next, a spiral groove 7a is formed in the insulating layer 5 by the groove 7a.
b and their positions are exactly matched (FIG. 10
(B)). At this time, the groove 7a is formed by etching, and the etching time at that time is strictly controlled so that the groove 7a does not reach the upper surface of the lower core 4. Groove 7
After a is formed, a conductor film such as Cu is formed therein to complete the coil conductor 7 (FIG. 11A).

Next, an insulating layer 10 is formed in a portion excluding the two intermediate cores 9a and 9b (FIG. 11B). Also,
Forming an upper core 12 in a region above the lower core 4;
Further, the insulating layer 11 is formed leaving the upper core 12 (FIG. 12A).

Next, the coil conductor 7 is formed on the insulating layers 10 and 11.
Is formed and a conductor 13 is buried therein (FIG. 12B). Further, a lead portion 14 connected to the coil conductor 7 via the conductor 13 is formed. Finally, it is cut along a cutting line BB ′ in the figure, and this cut surface is used as a sliding surface. Further, as shown in FIG.
5. The thin film magnetic head is completed by sequentially providing the alloy layer 26 and the lead wire 27.

[0018]

However, Japanese Patent Application Laid-Open No. Hei 7-2
According to the thin-film magnetic head disclosed in Japanese Patent No. 72217, there is a problem that the number of steps for forming a coil is larger than that of a conventional thin-film magnetic head. That is, since the coil conductor 7 is composed of two layers, the lower layer formed in FIG. 9B described above and the upper layer formed in FIG. 10B and FIG. Therefore, the number of steps for forming the coil is twice as large as that in the related art.

Moreover, in the step shown in FIG.
When the groove 7a is formed, it must be formed so that its position exactly coincides with the lower layer side of the coil conductor 7, so that there is a problem that the mask pattern must be aligned with high accuracy. . Furthermore, the lower core 4
In the upper region, when the groove 7a is etched, the coil conductor 7 must be etched so as to leave a part of the insulating layer 5 so as to insulate the coil conductor 7 from the lower core 4, so that the etching time must be strictly controlled. There was also a problem that there is.

Even when the etching time is strictly controlled as described above, the bottom of the formed groove 7a has a relatively large etching depth distribution, so that the thickness of the remaining insulating layer is small. It will vary from place to place. For this reason, in order to prevent the groove 7a from partially reaching the lower core 4, it is necessary to set the etching time short so that the insulating layer is left with a thickness of 1 μm or more.
For this reason, there has been a problem that the cross-sectional area of the coil conductor in the internal region of the magnetic head is reduced, or the thickness of the entire thin film magnetic head cannot be reduced.

The present invention has been made in view of the above problems, and provides a thin-film magnetic head having a low DC resistance of a coil without changing the head performance and head shape and without increasing the number of manufacturing steps. It is intended to be.

[0022]

In order to achieve the above object, in a method of manufacturing a thin film magnetic head according to the present invention, a lower core and an upper part arranged to face the lower core at a predetermined distance are provided. A method for manufacturing a thin-film magnetic head, comprising: a core; and a coil at least partially passing through an internal region between the lower core and the upper core, wherein the lower core and a first insulating layer are formed on a substrate. A second step of forming an etching stop layer on at least a part of the upper surface of the lower core;
A third step of forming a second insulating layer on the insulating layer and the etching stop layer;
Is etched to the etching stop layer, and the second insulating layer and the first insulating layer are formed outside the internal region.
Forming a coil-shaped groove having a bottom surface partially below the upper surface of the lower core outside the inner region by etching the insulating layer.
And a fifth step of forming the coil by filling the groove with a conductive material, and a sixth step of forming the upper core above the second insulating layer. Therefore, in the manufacturing method according to the present invention, the groove for forming the coil having a large cross-sectional area that extends below the upper surface of the lower core outside the internal region of the magnetic head is formed.
It can be obtained by one-stage etching.

Further, according to the present invention, there is provided a thin film magnetic head comprising: a lower core formed in an insulating layer; an upper core formed above the lower core with the insulating layer interposed; and at least a part of the lower core. An etching stop layer formed on
A portion passes through an internal region between the lower core and the upper core, and reaches the etching stop layer in the internal region, and extends below the upper surface of the lower core outside the internal region. A coil-shaped groove provided in the insulating layer by etching, and a coil formed by filling the groove with a conductive material. The coil is insulated from the lower core by the etching stop layer. It is characterized by the following. Therefore,
The coil is reliably insulated from the lower core. Further, since the etching stop layer can be formed as a layer having a small etching depth distribution, the insulation can be ensured even with a small film thickness. Therefore, the thickness of the etching stop layer can be suppressed, the cross-sectional area of the coil in the internal region of the thin-film magnetic head can be increased, and the DC resistance of the coil can be reduced.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In the following description, FIGS.
2, the same parts and members as those in the thin film magnetic head according to Japanese Patent Application Laid-Open No. 7-272217 are denoted by the same reference numerals, and redundant description thereof will be omitted.

First Embodiment First, a first embodiment of the thin-film magnetic head according to the present invention will be described. FIG.
1 is a perspective view of a thin-film magnetic head according to the embodiment.
The thin-film magnetic head of the present embodiment has three insulating layers 2, 5, and 11 stacked, and the insulating layers 2 and 11 include:
The lower core 4 and the upper core 12 are formed to face each other with the insulating layer 5 interposed therebetween. Also, between the lower core 4 and the upper core 12, two intermediate cores 9a,
9b is arranged so that one is located at the front of the magnetic head and the other is located at the rear. Further, a spiral groove is formed around the intermediate core 9b by etching so that a part thereof passes between the lower core 4 and the upper core 12. In a region where the groove is not sandwiched between the lower core 4 and the upper core 12, the lower surface is a deep groove reaching below the upper surface of the lower core 4. The groove is filled with a conductive material, and the conductive material forms the coil conductor 7. On the other hand, on the upper surface of the lower core 4, an etching stop layer 16 for the insulating layer 5 is formed. The etching stop layer 16 is formed in a region corresponding to the lower surface of the coil conductor 7 and a region corresponding to the lower surface of the intermediate core 9a, and has a function of insulating the coil conductor 7 from the lower core 4; And a function as a gap layer between the core 4.

FIGS. 2 to 5 are diagrams schematically showing steps of manufacturing the thin-film magnetic head of the present embodiment. Hereinafter, a method of manufacturing the thin-film magnetic head according to the present embodiment will be described with reference to FIG.

(A) First, in step 1, FIG.
As shown in FIG. 5, a layer 15 made of a soft magnetic material is formed on a substrate 1. This layer is formed by a thin film forming technique such as sputtering or vapor deposition.

(B) In step 2, as shown in FIG. 2 (b), the soft magnetic layer 15 is formed by photolithography and etching to form the lower core 4.

[0030] In (c) step 3, as shown in FIG. 2 (c), on a substrate 1, an insulating layer 2 made of SiO ₂ is formed by a method such as sputtering or CVD. After the insulating layer 2 is formed to a thickness sufficient to embed the lower core 4 once, it is polished and smoothed until the upper surface of the lower core 4 is exposed.

(D) In step 4, as shown in FIG. 3A, an insulating layer 16 made of Al ₂ O ₃ is formed on the lower core 4 and the insulating layer 2 by a method such as sputtering or CVD. Is done.

(E) In step 5, as shown in FIG. 3B, the insulating layer 16 is formed into a predetermined shape by photolithography and etching. Here, the predetermined shape refers to, for example, a shape of a portion of the upper surface of the lower core 12 excluding a rear region where the intermediate core 9b is provided.

(F) In step 6, as shown in FIG. 3C, a layer 17 of a soft magnetic material is further formed on the substrate 1 obtained by the fifth step by a thin film forming technique such as sputtering or vapor deposition. Apply film.

(G) In step 7, as shown in FIG. 4A, the layer 1 is formed by photolithography and etching.
7, two intermediate cores 9a and 9b are formed. The intermediate core 9b is provided on the lower core 4 in a region where the insulating layer 16 is not provided. On the other hand, the intermediate core 9a
Are formed on the front upper surface of the lower core 4 via the insulating layer 16. By forming the intermediate core 9a in this way, the insulating layer 16 becomes a gap layer that forms an interval of a predetermined width between the intermediate core 9a and the lower core 4.

In step (h), as shown in FIG. 4B, an insulating layer 5 made of SiO ₂ is provided on the substrate 1 by a method such as sputtering or CVD. The insulating layer 5
Once the intermediate cores 9a and 9b are provided to a thickness sufficient to be embedded, they are polished and smoothed until the upper surfaces of the intermediate cores 9a and 9b are exposed.

In step (i), as shown in FIG. 4C, after a resist film is applied to the upper surface of the insulating layer 5, the pattern of the coil conductor 7 is formed on the resist film by photolithography or the like. Is formed so as to be located substantially at the center thereof. Further, after the resist film having the above pattern is formed, the insulating layer 5 and the insulating layer 2 are etched. For this etching, reactive ion etching (RIE) using an etching gas such as CF ₄ gas or CHF ₃ gas may be used. For example, if CHF ₃ gas is used, the insulating layer 5 (SiO ₂ ) and the insulating layer 16 (Al ₂ O
The etching can be performed under the condition that the etching rate ratio with ₃ ) is 20: 1. As a result, the insulating layer 16 functions as an etching stop layer for reactive ion etching. In the region above the lower core 4, the etching apparently stops when the etching reaches the insulating layer 16. on the other hand,
In a region where the lower core 4 does not exist, the etching proceeds to the inside of the insulating layer 2. By this one etching step, the depth does not reach the lower core 4 in the region where the lower core 4 is present, but is lower than the position where the upper surface of the lower core 4 is located in the region where the lower core 4 is not present. A groove 18 whose depth reaches the position is obtained.

(G) In step 10, as shown in FIG. 5A, a thin film forming technique such as sputtering or vapor deposition is used.
The groove 18 is filled with a conductive material, and the upper surface thereof is smoothed by polishing. By this step, the coil conductor 7 is formed in the groove 18. The coil conductor 7 is insulated from the lower core 4 by the insulating layer 16 above the lower core 4, and in a region where the lower core 4 does not exist, the lower core 4
And has a large cross-sectional area.
Here, as the conductive material, for example, copper (C
u), gold (Au), aluminum (Al), silver (Ag)
Can be used.

(G) In step 11, as shown in FIG. 5B, an insulating layer 10 is formed in a portion excluding the two intermediate cores 9a and 9b.

(ヲ) In step 12, as shown in FIG. 5C, an upper core 12 made of a soft magnetic material is formed at a position facing the lower core 4.

(W) Although the step 12 and subsequent steps are not shown in FIG. 2 and the like, according to the same steps as FIGS. 12A and 12B described in Japanese Patent Application Laid-Open No. 7-272217, the insulating layer 11 is formed. , Conductor 13 and lead wire 14 are formed. Finally, the head manufactured in any of the regions including the intermediate core 9a is cut, and a lead wire or the like is attached to complete the thin-film magnetic head.

As described above, in the thin-film magnetic head of this embodiment, since the etching stop layer is provided between the lower core 4 and the insulating layer 5, as described in Step 9, the insulating layer 2 5, it is possible to form one groove 18 having two different groove depths in one etching step. Therefore, when manufacturing a thin-film magnetic head having a low DC resistance of the coil, when forming the coil conductor 7 like a conventional thin-film magnetic head, the lower layer side and the upper layer side are separately formed, and the manufacturing process is performed. There is no problem that the number increases, and there is no manufacturing difficulty that the upper layer side must be accurately positioned and formed on the lower layer side. Further, since the etching of the insulating layer on the upper side of the lower core 4 substantially stops at the etching stop layer and does not reach the lower core 4, it is not necessary to strictly control the etching time of the insulating layer 5 as in the related art. Absent.

In this embodiment, the etching stop layer also serves as a gap layer between the intermediate core 9a and the lower core 4 at the same time. Therefore, the etching stop layer is formed simultaneously with the gap layer by the same process as that for forming the gap layer in the conventional thin film magnetic head. Therefore, also from this point, the present embodiment is
This makes it possible to manufacture a thin-film magnetic head having a low DC resistance of the coil without increasing the number of steps as compared with the related art.

Further, in the conventional thin-film magnetic head, the thickness of the bottom surface of the groove formed by etching becomes non-uniform, whereas an etching stop layer is formed on the upper surface of the lower core 4 as in this embodiment. In this case, since a flat layer can be formed relatively easily, it is not necessary to increase the thickness of the etching stop layer in obtaining an insulating film. The etching stop layer is made of Al ₂ O ₃ , Zr
The film thickness can be suppressed to be thin by being formed from a highly insulating material such as O ₂ . For example, when Al ₂ O ₃ is used as in this embodiment, the thickness of the etching stop layer can be reduced to about 10 nm. From this, in the thin-film magnetic head of the present embodiment,
The cross-sectional area of the coil conductor in the inner region of the head is enlarged to be larger than that of the thin-film magnetic head disclosed in Japanese Patent Application Laid-Open No. 7-272217, and the DC resistance of the coil is further reduced. The thickness of the entire thin-film magnetic head is suppressed while maintaining the thickness of the thin-film magnetic head, and the size of the entire thin-film magnetic head can be further reduced.

Furthermore, in the present embodiment, since the groove for the coil conductor in the outer region of the head is formed by one etching, a coil conductor having uniform vertical side walls can be obtained. When a groove is formed by two-stage etching as in the thin film magnetic head disclosed in Japanese Patent Application Laid-Open No. 7-272217, a step is formed between the upper layer and the lower layer of the coil conductor. However, such a problem can be avoided in the present embodiment.

(Second Embodiment) In the first embodiment, a case has been described in which a thin film magnetic head is manufactured by forming an etching stop layer also serving as a gap layer. However, the etching stop layer is not necessarily required to serve also as a gap layer. It is not necessary to form them, and they may be formed separately and independently. Here, as a second embodiment of the present invention,
A thin-film magnetic head in which an etching stop layer is formed independently of a gap layer will be described.

FIG. 6 is a view showing a part of the manufacturing process of the thin-film magnetic head according to the present embodiment. The manufacturing process of the thin film magnetic head according to the present embodiment is basically the same as the manufacturing process of the first embodiment shown in FIG.
Is replaced with steps 15 to 17 shown in FIG.

Here, steps 15 to 17 will be described as follows.

(F) First, in step 15, an insulating layer 20 made of Al ₂ O ₃ is formed on the upper surface of the lower core 4 and the insulating film 2 as shown in FIG. At this time, the insulating layer 20 is formed to a thickness of 10 nm to 1 μm. The thickness is set to 10 nm or more because this is the minimum thickness required to insulate the coil conductor 7 from the lower core 4.

(Y) Next, in step 16, as shown in FIG. 6B, the insulating layer 20 formed in the previous step is formed into a predetermined shape, and To obtain the etched top layer. Here, the predetermined shape refers to, for example, the upper surface of the lower core 4 and the intermediate cores 9a and 9
Refers to the shape of a part excluding a part of a front part and a rear part where b is formed.

(G) Next, in step 17, as shown in FIG. 6C, a non-magnetic layer 21 which will later become a gap layer between the intermediate core 9a and the lower core 4 is formed. Non-magnetic layer 21
Is formed on the front side of the thin-film magnetic head in a region on the upper surface of the lower core where the insulating layer 20 is not formed.

As described above, in this embodiment, since the etching stop layer is formed independently of the gap layer, the thickness of the etching stop layer can be determined independently of that of the gap layer. Therefore, the thin-film magnetic head of the present embodiment has the same effects as the thin-film magnetic head of the first embodiment, such as that the coil conductor and the lower core are reliably insulated from each other. This has the effect that the etching stop layer can be formed by freely setting the film thickness in accordance with the performance or the material forming the insulating layer or the film quality of the insulating layer.

(Other Embodiments) The present invention is not limited to the above embodiment. The above embodiment is merely an example, and any structure having substantially the same structure as the technical idea described in the claims of the present invention and having the same function and effect can be obtained. It is included in the technical scope of the present invention.

For example, in the above embodiment, the case where the insulating layers 2 and 5 are formed of SiO ₂ and the insulating layer 16 is formed of Al ₂ O ₃ has been described. In particular, when the etching is performed by the reactive ion etching method, the insulating layer 2
And 5, the insulating layer 16 can function as an etching stop layer, that is, if the etching rate ratio of those layers is sufficiently large, for example, 20: 1, the insulating layer 16 may be formed from another material. For example, the insulating layers 2 and 5 may be formed from TiO ₂ or Ta ₂ O ₅ or the like, and the insulating layer 16 may be formed from ZrO ₂ or the like.

The etching stop layer is used to prevent the lower core from being etched in the step 9 for forming the groove 18 and to prevent the coil conductor 7 from being etched.
It may be formed in the minimum area of the upper surface of the lower core required to insulate it from the upper surface of the lower core, and need not necessarily be formed in a wider area as in the above embodiment.

It should be noted that the reactive ion etching (RIE) is particularly referred to in this embodiment because the R
The IE can increase the selectivity between the etching stop layer and the etching stop layer, and has excellent etching directionality, and is suitable for processing a groove for forming a coil conductor to a high aspect ratio. Because there is.
Even if an etching method other than RIE is used, the groove may be formed by ECR or ion milling.

[0056]

As described above in detail, according to the present invention, a step of forming an etching stop layer for the second insulating layer on the upper surface of the lower core is provided.
When the second insulating layer is etched in the third step, the etching is stopped at the etching stop layer in the inner region, so that the etching time is not strictly controlled, and the groove portion outside the inner region can be formed in one etching step. Can be made larger than the cross-sectional area in the internal region, and it becomes possible to easily manufacture a thin-film magnetic head having a large cross-sectional area of the coil outside the internal region and a small DC resistance.

Further, according to the present invention, the coil is insulated from the lower core by the etching stop layer formed on the upper surface of the lower core. It is also possible to increase the cross-sectional area of the coil, and to provide a thin-film magnetic head having a smaller DC resistance of the coil.

Further, according to the present invention, since the etching stop layer also serves as the gap layer, the thin-film magnetic head having a small DC resistance of the coil without increasing the number of steps from the number of steps for forming the gap layer in the conventional thin-film magnetic head. It became possible to manufacture a head.

Further, according to the present invention, it becomes easy to manufacture a thin film magnetic head having a small DC resistance of a coil by using an etching method suitable for processing a groove having a high aspect ratio.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a thin-film magnetic head according to a first embodiment of the present invention.

FIG. 2 is a view schematically showing a step of manufacturing the thin-film magnetic head according to the first embodiment of the present invention.

FIG. 3 is a view schematically showing a step of manufacturing the thin-film magnetic head according to the first embodiment of the present invention, which is a continuation of FIG. 2;

FIG. 4 is a view schematically showing a step of manufacturing the thin-film magnetic head according to the first embodiment of the present invention, which is a continuation of FIG. 3;

FIG. 5 is a view schematically showing a step of manufacturing the thin-film magnetic head according to the first embodiment of the present invention, which is a continuation of FIG. 4;

FIG. 6 is a diagram showing a part of the manufacturing process of the thin-film magnetic head according to the second embodiment of the present invention.

FIG. 7 is a diagram illustrating an equivalent circuit of a head rotary transformer and a relationship between a low-frequency cutoff frequency and a DC resistance in the equivalent circuit.

FIG. 8 is a diagram showing a thin-film magnetic head disclosed in Japanese Patent Application Laid-Open No. 7-272217.

FIG. 9 is a diagram illustrating a manufacturing process of the thin-film magnetic head disclosed in Japanese Patent Application Laid-Open No. 7-272217.

10 is a view illustrating a step of manufacturing the thin-film magnetic head disclosed in JP-A-7-272217, which is a continuation of FIG. 9;

11 is a view illustrating a step of manufacturing the thin-film magnetic head disclosed in JP-A-7-272217, which is a continuation of FIG. 10;

12 is a view illustrating a step of manufacturing the thin-film magnetic head disclosed in JP-A-7-272217, which is a continuation of FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2, 5, 10, 11, 17, 20 Insulating layer 4 Lower core 7 Coil conductor 8 Non-magnetic layer 9 Intermediate core 12 Upper core G gap 15, 17 Layer made of soft magnetic material 16 Etching stop layer 18 Groove 21 Non Magnetic layer 25 Pad portion 26 Alloy layer 27 Lead wire

Claims (4)

[Claims] 1. A lower core, an upper core arranged to face the lower core at a predetermined distance, and a coil at least partially passing through an internal region between the lower core and the upper core. A method for manufacturing a thin-film magnetic head comprising: forming a first insulating layer on a substrate;
Forming a second insulating layer on the lower core, the first insulating layer, and the etching stop layer; forming a second insulating layer on at least a portion of the upper surface of the lower core; A third step of etching the second insulating layer to the etching stop layer in the internal region and etching the second insulating layer and the first insulating layer outside the internal region. A fourth step of forming a coil-shaped groove having a bottom surface below the upper surface of the lower core outside the inner region through the inner region, and forming the coil by filling the groove with a conductive material. A fifth step of forming the upper core above the second insulating layer;
And a method for manufacturing a thin-film magnetic head. 2. Between the second stage and the third stage,
An intermediate core disposed in the internal region, wherein one end is disposed on an upper surface of the etching stop layer to form an intermediate core having a predetermined gap with the lower core. Item 3. A method for manufacturing a thin film magnetic head according to Item 1. 3. A lower core formed in an insulating layer, an upper core formed above the lower core with the insulating layer interposed therebetween, and an etching stop layer formed on at least a part of the lower core. A portion partially passes through an internal region between the lower core and the upper core, and reaches the etching stop layer in the internal region, and extends below the upper surface of the lower core outside the internal region so as to reach the etching stop layer. A coil-shaped groove provided in the insulating layer by etching, and a coil formed by filling the groove with a conductive material, wherein the coil is insulated from the lower core by the etching stop layer. A thin-film magnetic head. 4. An intermediate core disposed in the inner region and having one end connected to the upper core, wherein the etching stop layer is provided between the other end of the intermediate core and the lower core. 4. The thin-film magnetic head according to claim 3, wherein said thin-film magnetic head also serves as a gap layer between said intermediate core and said lower core.