JPS63259814A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To decrease DC electric resistance by specifying the coil wire width in a broad wiring part which is not covered by an upper magnetic core to the width of >=1.5 times the coil wire width in a wiring part which is covered by the upper magnetic core and specifying the change in the wire width in the curved part of coils at <=1.5 times. CONSTITUTION:The coil 2 of, for example, 3 turns formed via an insulating layer on a lower magnetic core 1 is the spiral type electromagnetic conversion coil formed by specifying the coil wire width in the wiring part to be uncored by the upper magnetic core 4 in the part Lb lower than a magnetic core contact part 6 to >=1.5 times the coil wire width of the wiring part to be covered by the upper magnetic core 4 in a range Lf from the contact part 6 to a magnetic gap part 5 and specifying the change in the coil wire width in the curved part where the coil wire width is changed to <=1.5 times. The influence of resist deformation is minimized and the DC electric resistance is decreased by using such coil.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thin film magnetic head, and particularly to its coil shape.

[Conventional technology]

Conventionally, thin-film magnetic heads have been manufactured using thin-film deposition and photolithography techniques, similar to the manufacturing process used for semiconductor ICs, etc., and because they can be formed into minute shapes, they are suitable for magnetic circuits and electrical circuits for signal conversion. The dimensions can be reduced, and therefore the magnetic head can be easily integrated. In addition, the inductance and capacitance of the circuit can be reduced, the resonance frequency can be easily placed in the high range, and the effective magnetic permeability can be increased in the high range by thinning the metal magnetic material. Because the generated magnetic field distribution is steep, it is useful as an electromagnetic conversion element in a high frequency region. Furthermore, as a feature of the process, it is advantageous for mass production of elements having the same shape and the same function.

Due to the above advantages, it has already been put into practical use as a magnetic head for computer hard disks, and it is expected that its range of use will expand to various magnetic recording and reproducing devices.

Furthermore, thin film magnetic heads are required to have more advanced microfabrication technology in order to improve recording and reproducing efficiency and to achieve higher integration.

In particular, the electromagnetic transducer coil in such a thin-film magnetic head has a winding portion with a film thickness of several μm, a pitch of 10 μm or less,
A pattern with a line width of several μm is required.

FIG. 5 is a schematic plan view of an upper notch showing an example of a conventional thin film magnetic head, FIG. 6 is an enlarged plan view of a coil pattern near the bent portion 2a of FIG. 5, and FIG. FIG. 7(a) is a cross-sectional view taken along line A-A' of the coil resist pattern in FIG. 6; FIG. 6 is a cross-sectional view taken along line BB' of the coil resist pattern in FIG. 6, and FIG. 8 is a diagram for explaining the schematic steps of a conventional gI film magnetic head coil wiring method.

In the figure, 1 is a lower magnetic core in which a magnetic film such as permalloy or sendust is formed on a magnetic substrate such as ferrite or a non-magnetic substrate, and 2 is a lower magnetic core formed on the lower magnetic core 1 with an insulating layer (not shown) interposed therebetween. For example, in a 3-turn coil, with respect to the coil line width of the wiring portion covered by the L portion magnetic core 4 in the range Lf from the contact portion 6 of the upper and lower magnetic cores to the magnetic gap portion 5, the coil width below the magnetic core contact portion 6 3 is an electromagnetic conversion coil with a larger coil wire width in the wiring portion not covered by the upper magnetic core 4; 3 is a coil lead wire;
4 is an upper magnetic core, 5 is a magnetic gap, 6 is a contact portion of the upper and lower magnetic cores, 7 is a conductive material, and 8 is a resist coated on the conductive material 7.

First, a conventional method for manufacturing a thin film magnetic head will be explained with reference to FIGS. 5 to 8.

Step 8a is performed to form a lower magnetic core made of a magnetic substrate such as ferrite, or a lower magnetic core formed by forming a magnetic film such as permalloy or sendust on a non-magnetic substrate. A spiral electromagnetic conversion coil forming step 8b is performed in which an insulating layer is formed on the coil, an insulation treatment is performed, and the coil line width is changed at the bent portion of the coil for wiring. Next, a coil lead wire forming step 8C is performed to form a coil lead wire 3 through an insulating layer, and a magnetic gap 510 is formed.
After depositing a nonmagnetic material such as No. 2 on the gear forming surface F of the lower magnetic core 1, an upper magnetic core forming step 8d is performed in which the upper magnetic core 4 is further formed via an insulating layer.

Further, the upper layer is covered with a protective film (not shown) to complete the QF process, and then a protective plate (not shown) is bonded, the chip is cut, and the shape is shaped to complete the thin film magnetic herad chip.

Next, the coil in the conventional thin film magnetic head will be described in detail, particularly the coil line width.

The recording and reproducing efficiency of a thin film magnetic head largely depends on the magnetic resistance of the magnetic core. The lower the magnetic resistance, the higher the recording and reproducing efficiency. This magnetic resistance becomes smaller as the length of the magnetic flux flowing through the magnetic core, that is, the magnetic path length becomes shorter.

From the magnetic gap 5 in FIG.
The length up to is required to be small for the reasons mentioned above.

Therefore, the electromagnetic conversion coil 2 in the range of length Lf, that is, the portion covered by the upper magnetic core 4, must be made finer in order to obtain the desired reproduction voltage by a predetermined number of turns.

On the other hand, in the range shown by the lengths t and h in FIG. 5, that is, in the wiring part of the electromagnetic conversion coil 2 that is not covered by the upper magnetic core 4, there is no relationship between the length Lb and the magnetic resistance. Rather, it is more effective to reduce head impedance noise by increasing the cross-sectional area of the conductive material and increasing the line width of the electromagnetic conversion coil 2 in order to reduce DC electrical resistance.

For example, in FIG. 5 showing a 3-turn electromagnetic transducer coil 2, the line width below the magnetic core contact part 6 extends from the magnetic core contact part 6 to the magnetic gap 5. It is a big deal.

According to this wiring method, an efficient thin film magnetic head with low magnetic resistance and low impedance noise can be obtained.

[The problem that the invention attempts to solve]

However, the bent portion 2 of the electromagnetic conversion coil 2 in FIG.
As shown in FIG. 6, which is an enlarged view of a, if the line width after a bend in the wiring is immediately changed at the bend in the wiring pattern, the following defects will occur.

A solid line 2b in FIG. 5 indicates a photomask pattern with a line width of several μm used to form the electromagnetic conversion coil 2. A resist coated on a conductive material is exposed through the photomask and developed. do.

As mentioned above, when the line width is 10 μm or less, it is advantageous to use a trial process, such as plasma etching, which causes less site etching compared to a wet process. required. That is, the post-bake after the resist phenomenon requires curing by high temperature treatment at 120''C or higher, for example.

This post-baking hardens the resist from the surface.

At the time of sand stopping, the ridge line of the resist surface is
It transforms as shown by the dotted chain line. A cross section in that case is shown in FIG. Figure 7 (b
) The deformation of the resist 8 of the conductive material 7'' is shown in FIG. 7(a).
The deformation of the resist 8 is larger than that of the resist 8, and the height is also lower.

The cause of this deformation is that when the resist 8 is cured, the surface tension moves and the bent portions are not pulled inward. This is because it is pulled toward the bottom of Figure 6.

For example, when etching is performed with the resist shape shown in FIG. 6, the coil line width at the section B-B' in FIG.
Since it is smaller than the area -A' and the thickness of the resist 8 is also thin, the electromagnetic conversion coil -F layer is overetched, causing defects such as increased electrical resistance and disconnection.

In particular, in order to increase the cross-sectional area of the electromagnetic conversion coil 2,
If it is desired to increase the aspect ratio of the pattern, a resist thickness of 8 μm or more is required.

As a result, the deformation effect due to post-baking becomes more pronounced, and there is a great possibility that the defective rate will increase.

Also, from the viewpoint of electrical resistance, the coil wire width of the thick part is
It is desirable that the coil line width be at least 1.5 times the width of the coil line at the thinnest part, but if the coil line width is changed by 1.5 times or more at the bent portion, the above-mentioned drawbacks will be noticeable and disadvantageous.

As shown in 1- above, in the conventional example, when performing the spiral electromagnetic conversion coil wiring process in which the coil wire width is changed by 1.5 times or more at the coil bending part on the lower magnetic core, There was a problem in that it caused defects such as an increase in electrical resistance and disconnection, and there was a great possibility that the defective rate would increase.

This invention was made to solve the above-mentioned conventional problems, and aims to provide a thin film magnetic head with low magnetic core and low coil electrical resistance, which is highly efficient and has low noise. shall be.

[Means for Solving the Problems] Therefore, in the present invention, a magnetic core, a spiral electromagnetic conversion coil arranged on the lower magnetic core, and a magnetic A Vi IIQ magnetic head having a gap and a partial magnetic core formed by depositing a magnetic thin film at a position facing the lower magnetic core across the magnetic gap and a part of the coil, , the coil line width of the wide wiring portion not covered by the upper magnetic core is at least 1.5 times the coil line width of the wiring portion covered by the upper magnetic core, and the line width changes at the coil bending portion. The aim is to solve the above-mentioned problems and achieve the objective by reducing the distance by 1.5 times or less.

[Effect]

In the thin film magnetic head of the present invention, for example, by making the change in the coil line width at the bending portion 1.5 times or more F,
It is possible to change the line width by 1.5 times or more while suppressing the deformation of the resist due to post-baking.

〔Example〕

FIG. 1 is a schematic cross-sectional view showing a pattern of a thin-film magnetic head according to an embodiment of the present invention, and FIG. 2 is an enlarged view of the coil pattern near the bent portion 1a of FIG. 3 is an enlarged plan explanatory view of the case where the coil line width changing portion C-C' in FIG. 2 is rectangular, and FIG. 4 is a pattern of a thin film magnetic head which is another embodiment of the present invention. It is an upper notch schematic bottom explanatory view showing.

In the figure, 2 is an insulating layer (not shown) on the magnetic core 1.
For example, a 3-turn coil is formed through the magnetic core contact portion 6 to the magnetic gap portion 5.
Compared to the coil line width of the wiring part covered by the upper magnetic core 4, the coil line width of the wiring part not covered by the upper magnetic core 4 in the part Lh below the magnetic core contact part 6 is 1
．． This is a spiral electromagnetic conversion coil in which the coil line width is changed by a factor of 5 or more, and the change in the coil line width at the bending portion where the coil line width is changed is 1.5 times or less.

In the drawings, the same or equivalent components as those in the conventional example are represented by the same reference numerals, and redundant explanation will be omitted.

In addition, the manufacturing process of the thin film magnetic head of this embodiment, mainly the coil wiring process, is the same as the process explained in the conventional example using the process diagram of FIG. 8, except for the electromagnetic conversion coil forming process 8b. Since it is a name, its repeated explanation will be omitted.

The coil 2, which is a feature of this embodiment, is similar to the electromagnetic conversion coil 2 shown in FIG. The width is set to be at least 1.5 times wider than the coil line width of the part covered by the L magnetic core 4, that is, the part of the wiring that straddles the L magnetic core 4, and the change in the coil line width at the coil bend part of the wiring is set to be 1.5 times or less, for example, The coil wire width is the same and the binding is the same.

In FIG. 2, which shows an enlarged view of the bent portion 1a of FIG. 1, the coil line width is approximately the line width W from the bent portion to C-
The C'' position is tapered and varied.

When the shape of the coil is determined in this way, B-B in Figure 2
The resist at the position IZ] r, l:I As shown by the resist ridge line after post-hake shown by the two-dot chain line, the deformation due to the post-hake can be suppressed to a small extent, and therefore the line width can be reduced to 1.
5(H'<<).

In Fig. 2, the coil line width changing portion C-C' changes into a tapered shape, but as shown in Fig. 3, the coil line width changing portion C-C'
-C' can also be rectangular.

However, as shown in Fig. 3, the resist deformation at the rectangular coil line width changing portion is larger than the tapered resist deformation shown in Fig. 2, and a new problem of coil thinning occurs.
The shape of the tapered coil line width changing portion shown in FIG. 2 is desirable.

Although the above embodiment has been described using a two-element thin film magnetic head as an example, a case in which the number of elements -r is one is also conceivable.

In the case of multiple elements with 3 or more elements, the width of the element (W valley in Fig. 5 of the conventional example) cannot be made smaller than the track pitch, but in the case of ■ elements (1 track), , is not limited by track pitch.

FIG. 4 shows another embodiment of the present invention in the case of two elements, and as shown in the figure, even if there are many elements, when the number of elements is two, the spacing between adjacent elements is limited. Of course,
The element width W can be made larger on the side opposite to the adjacent side.

Therefore, when the prime f number is 2 or less, it is possible to increase the coil line width by 1.5 times or more even on the side surface of the element.

In FIG. 4, the coil line width on the non-adjacent side 4a of the element is set at least 1.5 times larger, and the change in line width at the coil bending part is set at less than 15 times, and the line width is approximately the same as that at the coil bending part. After changing the length, the line width is changed to increase the line width by 1.5 times or more.

According to the thin film magnetic head of each of the embodiments described above, the influence of resist deformation can be suppressed to a small level, and since the proportion of the wiring length with a large coil line width increases, a large It's effective or effective.

In the embodiment described above, the bent portion of the coil wiring is bent at an angle of 90 degrees, but according to the inventor's experiments, the same effect was found even when the bent portion was bent at an angle of 120 degrees or more. The bending angle at the bending part of this invention is 90°.
It is not limited to b.

Furthermore, it has been found that the effects of the present invention can be observed even when the bent portion is arcuate and the radius is about four times the coil line width or less.

As explained above, in a thin film magnetic head, the coil line width of the wide wiring part not covered by the magnetic core is
1.5 of the coil line width of the wiring part covered by the upper magnetic core
By setting the coil line width to 1.5 times or more and making the change in the coil line width at the bending part where the coil line width is changed to 1.5 times or less,
This produces a similar effect.

(1) In one step of photolithography, deformation of the resist shape due to post-baking of the resist can be suppressed.

(2) Therefore, by increasing the post-baking temperature to improve the heat resistance of the resist, it is possible to form fine coils with good precision, including in the edging process.

(3) The area occupied by the coil wiring in the portion covered by the upper magnetic core 4 can be reduced, making it possible to manufacture a highly efficient thin-film magnetic head with a small core magnetic path length and, therefore, small magnetic resistance.

(4) Coil wiring with low DC electrical resistance is possible,
Effective in reducing head impedance noise.

(5) Increase in direct current resistance due to creases at bent portions of the coil wiring and disconnection are eliminated, making it possible to manufacture thin-film magnetic heads with high yield.

〔Effect of the invention〕

As explained above, according to the present invention, there is provided a magnetic core, a spiral electromagnetic conversion coil disposed on the lower magnetic core, a magnetic gap disposed on the lower magnetic core, and a magnetic gap disposed on the lower magnetic core. The above-mentioned - across the gap and a part of the surface coil
A thin film magnetic head having a first part magnetic core and a first part magnetic core formed by depositing a magnetic thin film at a position opposite to the first part magnetic core, the coil line width of a wide wiring part not covered by the first part magnetic core. , by making the coil line width at least 1.5 times the coil line width of the wiring part that is applied to the magnetic core at 4V, and by making the change in line width at the bending part of the coil at least 15 times F, the resist shape can be improved. This has the effect of reducing DC electrical resistance.

[Brief explanation of drawings]

FIG. 1 is an explanatory schematic plan view with an upper notch showing a pattern of a thin film magnetic head which is an embodiment of the present invention, FIG. 2 is an explanatory enlarged plan view of a coil pattern near the bent portion of FIG.
FIG. 3 is an enlarged plan view of the coil line width changing portion shown in FIG. 2 having a rectangular shape, and FIG. FIG. 5 is a schematic plan view of an upper notch showing an example of a conventional thin film magnetic head, FIG. 6 is an enlarged plan view of the coil pattern near the bend in FIG. 5, and FIG. Fig. 7(a) is a cross-sectional view taken along line A-A' of the coil resist pattern in Fig. 6; Figure (b) is
8 is a cross-sectional view taken along line B-B" of the coil resist pattern in FIG. Core 2... Electromagnetic conversion coil 3... Coil leader line 4... Upper magnetic core 5... Magnetic gap 6... Magnetic core contact Part 7... Conductive material 8... Resist

Claims (1)

[Claims] A lower magnetic core, an electromagnetic conversion coil that is insulated and wired in a spiral shape on the lower magnetic core, a magnetic gap arranged on the lower magnetic core, and a part of the magnetic gap and the coil. A thin film magnetic head having an upper magnetic core formed by depositing a magnetic thin film at a position facing the lower magnetic core with the coil line width of a wide wiring portion not covered by the upper magnetic core. of,
1 of the coil line width of the wiring portion covered by the upper magnetic core
．． 5 times or more, and a change in line width at a bent portion of the coil is 1.5 times or less.