JP2534082B2 - Thin film magnetic head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head used in a PCM (Pulse Code Modulation) recording / reproducing device, an electronic still camera and the like, and in particular, an improvement of a coil conductor of an embedded multilayer spiral thin film magnetic head. Regarding

[Prior Art] A thin film magnetic head is a so-called multi-layer spiral thin film magnetic head in which a plurality of spiral coil conductors are formed in order to improve recording / reproducing efficiency by increasing the number of windings. Therefore, an embedded multi-layer spiral type thin film magnetic head has been put to practical use.

The embedded multi-layer spiral type thin film magnetic head has a third
As shown in FIGS. (A), (B) and (C), a lower magnetic body 50a made of amorphous or sendust or the like is formed on a magnetic or non-magnetic substrate 50, and SiO ₂ is further formed thereon.
The first insulating layer 51 made of, for example, is formed by sputtering, vapor deposition, or the like. Next, a lower layer coil conductor 52 made of Cu is formed thereon, then a second insulating layer 53 is formed on the lower layer coil conductor 52, and then an upper layer coil conductor 54 is formed between the lower layer coil conductors 52. Form the third insulating layer 55 on top,
Taper etching is performed to open a window for magnetically coupling the upper magnetic body 57 and the lower magnetic body 50a, and then a gap layer (not shown) made of SiO ₂ or the like is formed, and an amorphous or sendust layer is formed thereon. And the upper magnetic body 57 is formed.

[Problems to be Solved by the Invention] In the embedded multi-layer spiral thin film magnetic head described above, due to its structure, a large step is generated unless the upper coil conductor layer is optimally arranged in the lower coil conductor interval. [Fig. 3 (B), (C)].

When such a large step is generated, the third insulating layer 55 and the upper magnetic body 57 formed by a method such as sputtering.
The third insulating layer 55a and the upper magnetic body 57a located in the step portion are thinly deposited as compared with the flat portion. Therefore, in etching the upper magnetic body, the etching time of the upper magnetic body 57a located at the step portion is shorter than that of the upper magnetic body 57 located at the flat portion.

Therefore, when the etching of the upper magnetic body 57 located in the flat portion is completed, the third insulating layer 55a located in the step portion is completed.
May be over-etched and cause dielectric breakdown. In addition, the lower coil conductor 52 and the upper coil conductor 54
A particularly steep step occurs at the intersection of and. Therefore, in the thin film magnetic head disclosed in Japanese Unexamined Patent Publication No. 62-22218, the upper layer coil conductor and the lower layer coil conductor intersect as shown in FIGS. 4 (A), (B) and (C). A projecting portion 52a is provided on the lower coil conductor 52 at a portion to eliminate the step. In this case, the step is certainly eliminated in the part where the upper coil passes over the lower coil,
As can be seen from FIG. 4 (C), since the upper layer coil 54 is completely disposed on the lower layer coil 52 in other portions, the step is not eliminated, and the dielectric breakdown of the insulating layer 55 occurs in this portion. Will end up. Further, in the portion rearward of the upper magnetic pole, the distance l between the lower layer coils is set to about 20 to 30 μ, so the total length of the coils becomes long, the DC resistance becomes high, and noise due to the impedance of the head increases, S / N
May be deteriorated.

That is, in the conventional embedded multi-layer spiral thin film magnetic head, as described above, there was a problem that dielectric breakdown or conductor breakage of the upper coil during etching of the upper magnetic material, and S / N reduction due to increased DC resistance occurred. .

As a result of intensive experiments, the inventors of the present invention have shown that when the upper coil conductor 54 is disposed on the lower coil conductor space S, the amount δ of protrusion onto the lower coil conductor 52 [see FIG. 3 (B)]. ]
When the thickness is 20 μm or more, the level difference in the raised portion becomes large and the above problem occurs, but it was found that the level difference is reduced by setting the thickness to 20 μm or less.

Therefore, the present invention has been proposed in order to solve the above-mentioned drawbacks and does not cause dielectric breakdown or conductor breakage even when etching the upper magnetic body, and minimizes DC resistance to reduce S / N. An object is to provide a thin film head which can be improved.

[Means for Solving the Problems] In order to achieve the above object, the present invention is configured by stacking a plurality of layers of spiral coil conductors and an upper magnetic body on a lower magnetic body via an insulating layer. A thin-film magnetic head, characterized in that a coil conductor shape of a coil conductor region which is etched and not covered with an upper magnetic body having a predetermined shape is as follows.

i) 45 ° ≤ θ ≤ 60 °, 1.5S ≤ L ≤ 4.5S, where θ is the lower layer coil conductor inclination angle not covered by the upper magnetic body after etching L: Upper layer not covered by the upper magnetic body after etching Coil conductor width (μm) S: Lower coil conductor spacing (μm) that is not covered by the upper magnetic body after etching, and ii) In the region where the upper coil is crossed with the lower coil, The area CS of the space surrounded by the upper coil is 49 (μm ² ) ≦ CS ≦ 225 (μm ² ).

[Operation] As described above, the coil conductor shape of the coil conductor region which is etched and not covered with the upper magnetic body having a predetermined shape is i) 45 ° ≦ θ ≦ 60 °, 1.5S ≦ L ≦ 4.5S θ: Inclination angle of lower coil conductor that is not covered by upper magnetic body after etching L: Conductor width of upper coil that is not covered by upper magnetic body after etching (μm) S: Not covered by upper magnetic body after etching The lower-layer coil conductor spacing (μm) and ii) the area CS where the lower-layer coil and the upper-layer coil are surrounded by the area CS in which the lower-layer coil intersects with the upper-layer coil is 49 (μm ² ) ≤ Since it is arranged so as to satisfy CS ≦ 225 (μm ² ), the amount of step difference is extremely small, and even if the upper magnetic body is removed by etching,
Excessive over-etching of the insulating layer and etching of the upper coil conductor are eliminated. Further, a lower coil conductor spacing or the upper coil conductor spacing, the space area surrounded by these (CS) of 49 .mu.m ² or 225μm less than ^2, i.e. by a 7μm or 15μm or less in length. Since the coil length can be shortened, the DC resistance can be reduced and S /
N can be improved.

[Examples] Hereinafter, an example of the present invention will be described with reference to FIG.
This will be described in detail with reference to (B) and (C).

In the thin film magnetic head of the present invention, as the lower magnetic body 1, a ferromagnetic oxide substrate 10 such as Mn-Zn ferrite or Ni-Zn ferrite, or Fe-Ni system on a non-magnetic substrate such as ceramic. Alloy (Permalloy), Fe-Al-Si alloy (Sendust), Co-Nb-Zr alloy (Amorphous), or other composite substrate in which ferromagnetic metal materials are laminated, or Permalloy on the above-mentioned ferromagnetic oxide substrate. A composite substrate or the like in which ferromagnetic metal materials such as sendust or amorphous are laminated is used. The first insulating layer 2 made of SiO ₂ or the like is formed on the lower magnetic body 1 by sputtering or the like. Next, the lower layer coil conductor 3 made of a metal conductor such as Cu or Al is formed in a spiral shape at a predetermined interval.

Here, in the present invention, the lower layer coil conductor spacing S is set to 7 μm or more and 15 μm or less in order to minimize the coil DC resistance. Further, in order to make the dimensions of the photoresist to be the same as the photoresist after etching (pattern conversion difference = 0), after the after-baking is applied to the photoresist to be the mask when etching by ion milling, the incident angle of the ion beam ( Etching is performed at an angle of 0 ° to 15 ° with respect to the normal direction of the upper surface of the photoresist. By doing so, the coil conductor spacing after etching becomes the same as the photoresist pattern spacing, facilitating the photomask pattern design. Next, after depositing a second insulating layer 4 made of SiO ₂ or the like, a contact window (not shown) for connecting the lower layer coil conductor 3 and the upper layer coil conductor 5 is opened, and then the second insulating layer is formed. A metal conductor made of Cu, Al or the like is deposited so as to cover 4 and is etched by ion milling to form the upper coil conductor 5. At this time, as shown in FIG. 1 (A), the upper-layer coil conductor 5 has a coil conductor shape in a coil conductor region which is etched and not covered with the upper magnetic body having a predetermined shape, i) 45 ° ≦ θ ≦ 60 °, 1.5S ≤ L ≤ 4.5S, where θ: Inclination angle of lower coil conductor not covered by upper magnetic body after etching L: Conductor width of upper layer coil not covered by upper magnetic body after etching (μm) S : Lower coil conductor spacing (μm) that is not covered by the upper magnetic body after etching, and ii) Space where the upper coil crosses the lower coil and is surrounded by the lower coil and the upper coil. The area CS is arranged so as to satisfy 49 (μm ² ) ≦ CS ≦ 225 (μm ² ). Furthermore, in order to reduce the DC resistance of the upper layer coil conductor,
Since the space area (CS) is 49 μm ² or more and less than 225 μm ^2, it should be 7 μm or more and 15 μm or less like the lower layer coil conductor. If the incident angle of the ion beam when forming the upper layer coil conductor is set to 0 to 15 °, the region surrounded by the lower layer coil and the upper layer coil (A portion) will be an ion beam up to a region of 7 × 7 μm ^2. It was found that the short circuit between the upper coil did not occur and the short circuit did not occur. Further, when the distance S between the conductors is 15 μm or more, the DC resistance increases. If the spacing S is further large, when a photoresist serving as a mask is applied during pattern etching of the upper magnetic body 7 formed on the third insulating layer 6 via the third insulating layer 6, the photoresist is a lower coil and an upper coil. Since a sharp step difference is formed in the enclosed area (A portion), the film thickness of the portion of the upper magnetic body 7 where the photoresist is to be patterned fluctuates, and especially the film thickness of the upper magnetic body 7 avoids magnetic saturation. Therefore, when it is desired to increase the thickness to more than 10 μm, it is found from the experiment that the upper magnetic body 7 to be left is etched due to the variation in the film thickness.

Further, when an experiment was conducted by combining the upper layer coil conductor width L with the lower layer conductor spacing S as shown in Table 1 below, the lower layer coil conductor spacing S and the upper layer coil conductor width L were 1.5S ≦ L ≦ It meets 4.5S.

At this time, the inclination angle θ of the lower layer coil conductor after etching is
The angle was 45 ° to 60 °, and the level difference in the part where the upper and lower coil conductors exist was very gentle. Then, in the pattern etching of the upper magnetic body 7 formed on the upper layer coil conductor, the upper magnetic body can be uniformly etched, dielectric breakdown due to overetching of the third insulating layer 6, or the upper coil conductor 5 is also etched. And there was no disconnection.

By the way, the upper coil conductor 5 has a portion near the front gap (a portion where the above-mentioned upper magnetic body 7 is formed).
In the above, since the gaps are formed so as to fill the gaps between the lower coil conductors 3, the surfaces of these coil conductors 3 and 5 are formed to be substantially flat, and as a result, the upper magnetic body 7 is formed to be substantially flat. It is designed to obtain magnetic characteristics.

Next, FIG. 2 shows another embodiment of the present invention. In this embodiment, the upper coil conductor is formed as shown in the drawing, and similarly to the first embodiment, the upper coil conductor is a coil in the coil conductor region which is etched and is not covered with the upper magnetic body 7 having a predetermined shape. The conductor shape is i) 45 ° ≤ θ ≤ 60 °, 1.5S ≤ L ≤ 4.5S, where θ: Inclination angle of the lower coil conductor that is not covered by the upper magnetic body after etching L: Upper magnetic body after etching Conductor width of uncovered upper coil (μm) S: Lower coil conductor spacing (μm) not covered by the upper magnetic body after etching, and ii) in the region where the upper coil is arranged across the lower coil , The area CS of the space surrounded by the lower layer coil and the upper layer coil is arranged so as to satisfy 49 (μm ² ) ≤ CS ≤ 225 (μm ² ) and the direct current of the upper layer coil conductor is Lower layer coil conductor 3 to reduce resistance The width of the upper coil conductor 5 perpendicular taking large.

Also in this example, good magnetic characteristics were obtained without causing dielectric breakdown of the insulating layer formed in the lower layer or disconnection of the upper layer coil conductor as in the previous example.

Although the thin film magnetic head in which two layers of coil conductors are laminated has been described in each of the above embodiments, the present invention is also applicable to a thin film head in which two or more layers of spiral coil conductors are laminated.

Further, in each embodiment, the one-channel thin film magnetic head has been described, but the present invention is also applied to a so-called multi-channel thin film magnetic head having a plurality of thin film magnetic head elements.

[Advantages of the Invention] In a thin film magnetic head of the present invention, a plurality of layers of spiral coil conductors and an upper magnetic substance are laminated on a lower magnetic substance of a thin film magnetic head with an insulating layer interposed therebetween. The shape of the coil conductor in the coil conductor region which is not covered with the upper magnetic body having: i) 45 ° ≦ θ ≦ 60 °, 1.5S ≦ L ≦ 4.5S, where θ: is not covered with the upper magnetic body after etching Inclination angle of lower layer coil conductor L: Conductor width of upper layer coil which is not covered by upper magnetic body after etching (μm) S: Lower layer coil conductor interval (μm) which is not covered by upper magnetic body after etching and ii) In the area where the upper coil is arranged intersecting the lower coil, the area CS of the space surrounded by the lower coil and the upper coil is 49 (μm ² ) ≦ CS ≦ 225 (μm ² ). And As a result, even when the pattern of the upper magnetic body is etched, the insulating layer and the upper coil conductor are not etched, and the yield is improved.
In addition, the direct current resistance can be reduced and a thin film head with a good S / N can be provided.

[Brief description of drawings]

FIG. 1 (A) is a plan view showing an embodiment of the present invention, FIG. 1 (B) is a sectional view taken along the line aa in FIG. 1 (A), and FIG.
(A) bb sectional view, FIG. 2 is a plan view showing another embodiment according to the present invention, and FIGS. 3 and 4 are views for explaining a conventional thin film magnetic head. ) Is a plan view thereof, each (B) diagram is a sectional view taken along the line aa, and each (C) diagram is a sectional view taken along the line bb. 1 ... Lower magnetic body, 2,4,6 ... Insulating layer 3 ... Lower layer coil conductor, 5 ... Upper layer coil conductor 7 ... Upper magnetic body L ... Upper layer coil conductor width S ... Lower layer coil conductor spacing

Claims (1)

(57) [Claims] 1. A thin-film magnetic head comprising a plurality of spiral coil conductors and an upper magnetic body laminated on a lower magnetic body with an insulating layer interposed between the upper magnetic body and the upper magnetic body having a predetermined shape. A thin film magnetic head characterized in that the shape of the coil conductor in the uncovered coil conductor region is as follows. 45 ° ≤ θ ≤ 60 °, 1.5S ≤ L ≤ 4.5S, where θ: Inclination angle of lower layer coil conductor not covered by upper magnetic body after etching L: Upper layer coil not covered by upper magnetic body after etching Conductor width (μm) S: Lower coil conductor spacing (μm) that is not covered by the upper magnetic body after etching, and in the region where the upper coil is disposed across the lower coil, the lower coil and the upper coil The area CS of the enclosed space is 49 (μm ² ) ≦ CS ≦ 225 (μm ² ).