JPH0448451A - Manufacture of magnetic head for magneto-optical recording - Google Patents

Abstract

PURPOSE:To manufacture the magnetic head of high performance with good yield by laminating a coil conductor with repeated processes to form the coil conductor by using the photoresist mask of film thinner than the film thickness of the coil conductor obtained finally and forming the coil conductor of required thickness finally. CONSTITUTION:Since a photoresist mask is formed by using what is called lithography technique and a coil conductor is formed through the photoresist mask, the coil conductor of which width and height are high accurate is formed. Moreover, a process to form coil conductors 281, 282 and 283 through photoresist masks 271, 272 and 273 thinner than the thickness of a required final conductor 28 is repeated plural number of times and the coil conductor 28 of the required thickness is formed. That is, since the photoresist masks 271, 27>=2 and 273 are thin, the patterning accuracy of the respective photoresist masks 271, 272 and 273 becomes good. Thus, the coil conductor 28 with the good accuracy is formed finally and a magnetic head 29 of high performance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a magnetic head for magneto-optical recording that records information on a magneto-optical recording medium by magnetic field modulation.

[Summary of the invention]

In a method for manufacturing a magnetic head for magneto-optical recording, the present invention involves repeating the process of forming a coil conductor in a predetermined pattern on a substrate through a photosensitive resist mask having a predetermined film thickness multiple times to form a desired pattern on the substrate. By forming coil conductors laminated in a thick layer, it is possible to manufacture a magnetic head for magneto-optical recording having highly accurate coil conductors.

[Conventional technology]

As a recording method for a magneto-optical disk, a so-called magnetic field modulation method is known in which recording is performed using a magnetic field from a magnetic head while irradiating a magneto-optical disk with a laser beam.

FIG. 6 shows a schematic configuration of a magneto-optical disk recorder using this magnetic field modulation method. In the figure, (1) is a magneto-optical disk, (2) is an optical head arranged facing the - side of the magneto-optical disk (1), and (3) is the other side of the magneto-optical disk (1). A magnetic head, which is a source of an external magnetic field, is shown facing the optical head (2) on its surface.

The optical head (2) also functions as a pickup during playback, and has a laser diode (4) that is a laser light source.
), a polarizer (5), a hems flitter (6), an objective lens (7), a 172 wavelength plate [8), a polarizing beam splitter (9), photodetectors (10), (11), etc. On the other hand, the magnetic head (3) generally has a configuration in which, as shown in FIG. 7, a spiral coil conductor (13) is formed on a magnetic substrate (12), for example, when viewed from above. In such a magnetic head [3], the width T1 and pitch P (=T+G) of the coil conductor (13) are required to be on the order of several tens of micrometers due to the required specifications of the system in which it is used.

Conventionally, as a manufacturing method for such a magnetic head (3), a coil conductor (1) is printed on a magnetic substrate (12) by a screen printing method.
3), and a method of forming a coil conductor (13) by winding a single wire or a litz wire (several tens of micrometers in diameter) at a predetermined pitch on a magnetic substrate (12).

[Problem to be solved by the invention]

By the way, in the manufacturing method of the conventional magnetic head (3) described above, the yield rate in industrial production is extremely low and costs are inevitably high. In addition, in a system in which the magneto-optical disk is rotated at high speed and the distance between the magnetic head (3) and the magneto-optical disk (1) is Q, 1 mm, the height direction of the coil conductor (3) of the magnetic herad is Accuracy is strictly required, but the conventional magnetic head manufacturing method described above cannot achieve the accuracy in the height direction that meets this requirement. A method for manufacturing a magnetic head for magneto-optical recording having a conductor is provided.

Means for Solving the Problem 2 The present invention provides a predetermined pattern of coil conductors (28, ,)((28□), (2
83)) is repeated multiple times to form the substrate (21).
) A coil conductor (28) laminated to a desired thickness is formed to manufacture a magnetic helad (29) for magneto-optical recording.

[Two effects] In the manufacturing method of the present invention, a photosensitive resist mask is formed using a so-called phosphorography technique, and a coil conductor is formed through this photosensitive resist mask, so the coil conductor has high precision in both width and height. is formed.

Furthermore, the photosensitive resist mask (27,) ((272) is thinner than the desired final thickness of the coil conductor (28).
(27,)) through the coil conductor (28,) ((28
2) The process of forming (283)) is repeated multiple times to form a coil conductor (28) with a desired thickness. That is, the photosensitive resist mask (27,) (27°) (27,
) is thin, so each photosensitive resist mask (27, )(
The patterning accuracy of 27□) (27,) is good, and a coil conductor (28) with good precision is finally formed, resulting in a high-performance magnetic helad (29).

〔Example〕

Embodiments of the method for manufacturing a magnetic head for magneto-optical recording according to the present invention will be described below with reference to the drawings.

A method for manufacturing a magnetic head for magneto-optical recording using lithography technology will be described with reference to FIG.

First, as shown in FIG. 2A, after cleaning a magnetic substrate (for example, a ferrite substrate (21)), the ferrite substrate (21) is cleaned.
A photoresist mask (2
2) Form.

Next, as shown in FIG. 2C, a photoresist mask (
After forming the conductor (23a) by plating, evaporation, sputtering, etc. through the conductor (22), the photoresist mask (21) is lifted off, and as shown in the second diagram,
A desired magnetic head (24) is obtained by forming a spiral coil conductor (23) on a ferrite substrate (21).

According to this manufacturing method, if the dimensional accuracy of the ferrite substrate (21) is maintained, the width T and height d of the coil conductor (23) can be
Since the dimensional accuracy in the direction, that is, the tolerance, can be obtained on the order of 1 μm to 0.1 μm, the magnetic head (24) including the ferrite substrate (21) and the coil conductor (23) has extremely high precision.
is obtained. Therefore, advantages can be expected, such as increased mass productivity and cost reduction, less variation in properties and good yield, and the possibility of forming fine shapes.

By the way, in general, when exposing a photoresist film, when the pattern depth is deep, for example, about 15 μm, as in the target magnetic head for magneto-optical recording, a trapezoidal profile is formed as shown in FIG. 3A ( (The figure shows the case of a positive photoresist film).

The conductor (
When the photoresist mask (22) is plated and the photoresist mask (22) is lifted off, the shape of the coil conductor (23) becomes an inverted trapezoidal cross section as shown in FIG. 3C.

However, if this shape becomes extreme, the adjacent upper ends of the conductor plating will connect with each other, making it impossible to obtain a good coil conductor (23).

FIG. 1 shows an embodiment that improves this point. In this example, as shown in FIG. 1A, a magnetic substrate such as a ferrite substrate (21) is prepared, and after cleaning, the -
A conductive base film (26) is formed on the surface.

Next, as shown in FIG.
) is deposited with a thinner film thickness, e.g. 5 μm, exposed,
It is developed to form a first photoresist mask (27+) having a predetermined spiral pattern.

Next, as shown in FIG. 1C, conductor plating is applied to the substrate (21) through the first photoresist mask (27,), and a spiral-shaped first coil conductor (27,) with a film thickness of 5 μm is formed.
2B□) is deposited and formed.

Next, as shown in the first diagram, the first photoresist mask (27,) is removed.

Next, as shown in Figure 1, a positive photoresist film (28) is applied to the entire surface including the spiral coil conductor (28,).
7a=) is applied. Second positive photoresist film (27
The film thickness of a,) is t for the coil conductor (28+).
1-5 μm, and the groove between the coil conductors (28,) is t.

The thickness is 10 μm, and the entire surface is flat.

Next, the positive photoresist film (27a2) is exposed using an optical mask with the same pattern as above, and developed to form a spiral shape in which the top of the coil conductor (28,) is exposed, as shown in FIG. 1F. Second photoresist mask (272
> form.

Then, as shown in the 11th MG, conductor plating is applied through the second photoresist mask (272), and a second coil conductor (thickness: 5 μm) made of the same material is placed on the first coil conductor (28,). □) is laminated.

The second photoresist mask (272) is then removed as shown in FIG. 1H.

Next, as shown in FIG. 1, a positive photoresist film (27a3) is further deposited on the entire surface including the spirally laminated coil conductors (28,) and (28□).

This positive type photoresist film (27a3) has a film thickness of t3-5 μm on the coil conductor (28□) and t4=15 μm on the groove between the coil conductors, and is formed flat as a whole.

Next, the positive photoresist film (27a,) is exposed using an optical mask with the same pattern as above, and developed to form a third spiral photoresist mask (27,) as shown in FIG. 1J. do.

Then, as shown in the first ffiK, conductor plating is applied through the third photoresist mask (27,) and the second
A third coil conductor (film thickness: 5 μm> (283)) made of the same material is laminated on top of the coil conductor (28°).

Thereafter, the third photoresist mask (273) is removed (FIG. 1L), and the conductor base film (26) facing between the coil conductors is selectively removed.
1) On top of the coil conductor (2g, ), (28°) and (2
83> are laminated to form a coil conductor (28) with a desired film thickness (for example, d=15 μm thick) to obtain a desired magnetic head (29).

According to this manufacturing method, the desired coil conductor (28
) Photoresist film (27a1) (27a
2), (27a,) are applied, exposed and developed to form photoresist masks (27,), (272), (2), respectively.
73), so each photoresist mask (2
The cross-sectional shapes of the openings 7,), (27,), and (273) are not trapezoidal but substantially vertical rectangular, and a highly accurate photoresist mask can be obtained. Therefore, each photoresist mask (27□), (272), (273
), the first, second, and third coil conductors (28,) and (28□
), (283) are formed. The steps of forming the photoresist mask and plating the conductor are repeated multiple times to form the first, second, and third coil conductors (28,), respectively.
, (282), and (283) to form a coil conductor (28) with a desired thickness, it is possible to finally manufacture a highly accurate magnetic head (29).

In the above example, the photoresist mask is removed after each conductor plating and a new photoresist mask is formed, but in other cases, the photoresist mask is left after conductor plating in the previous process and the next step is performed. It is also possible to deposit a photoresist film and pattern it in the same way to form the next photoresist mask. However, in the former method, there is no problem even if the thickness of the conductor plating varies slightly, and the work is easier. However, in the latter case, it is necessary to strictly control the conductor plating film thickness, that is, to control the thickness of the conductor plating so that the top surface of the photoresist mask and the top surface of the conductor plating are the same.

Furthermore, although a positive type photoresist film was used as the photoresist film in the above example, a negative type photoresist film may also be used. However, at present, positive photoresists have better accuracy.

Further, although a magnetic substrate such as a ferrite substrate is used as the substrate (21), a non-magnetic substrate (ceramic or the like) may also be used.

On the other hand, when wet plating is used for conductor plating in manufacturing magnetic heads using the above-mentioned phosphorography technology and plating technology, if the width and pinch of the coil conductor become fine, problems may occur during conductor plating. There is. That is, if air is trapped in the spiral opening of the photoresist mask immediately before plating, and the plating continues, the coil conductor (31 ) a local constriction (32) occurs.

Here's how to improve this. That is, to form the spiral coil conductor (31) by wet plating, as described above, a photoresist film is applied, exposed, developed, and post-baked to form a photoresist mask, and then wet plating is performed to form the coil conductor (31). 31). In this example, between the boss baking and the wet plating process, the substrate (21) having the photoresist mask is swung in water or an alcohol bath to degas the spiral opening of the photoresist mask. Thereafter, conductor plating is applied in a leaky state, for example, in a copper plating bath to form a coil conductor (31). Here, it is possible to degas by shaking in the plating bath, but since the copper plating bath is an acidic bath, after placing the board (21) in the copper plating bath, immediately turn on the electricity and start plating. If this is not started, the conductor base film will be oxidized and the plating will be difficult to adhere to. Therefore, deaeration cannot be performed in the plating bath. In this example, it is important to degas it in water or an alcohol solution before putting it into the plating bath. By doing so, a magnetic head having a thin film coil conductor (31) without constrictions and having a uniform width and pitch can be obtained with a high yield. Furthermore, by performing deaeration treatment in water or an alcohol solution, it is possible to easily check which portions air is trapped in.

〔Effect of the invention〕

According to the present invention, the coil conductors are laminated by repeating the process of forming the coil conductor using a photoresist mask having a film thickness thinner than the film thickness of the coil conductor to be finally obtained, and finally the coil conductor with the desired thickness is formed. By forming this, a highly accurate coil conductor can be obtained, and a high-performance magnetic head can be manufactured with high yield.

[Brief explanation of drawings]

FIG. 1 is a manufacturing process diagram showing an example of a method for manufacturing a magnetic head for magneto-optical recording according to the present invention, FIG. 2 is a manufacturing process diagram showing a basic example of a manufacturing method for a magnetic head according to the present invention, and FIG. FIG. 4 is an explanatory diagram of a coil conductor used to explain the present invention, FIG. 5 is a sectional view taken along line A-A in FIG. 4, and FIG. A schematic configuration diagram of a magnetic disk recorder, FIG. 7 is a perspective view showing an example of a conventional magnetic head for magneto-optical recording. (21) is a ferrite substrate, (22), (27,),
(27□). (273) is a photoresist mask, (23) ,
(2g) [(28,)(282), (283)] is a coil conductor. Fig. 1 (Zonori Fig. (3 of ¥) Fig. (2 of Amount) 27, , 272.273 27α2, 27123 28, 281, 282.283 Ferrite substrate guide Kinoshita tcM photoresist cyst mask photoresist Hesho Coil fLa Sakitama Nayu - To Ishigoya for Kotokisho Collection / To No. 4 (Zono 4) 23. 4-m - Noelite Toshiki Soho - Tresist Mask Coil Guide Book + IJ Kinki Akiseki A Biography, To/Do Book Release January 1-Related! #6 Basics of Law/Process Figure 4 Cross-sectional view on line A-A Figure 5 3a 6-- &-- 9 -・-・lαl!-・Light, conspiracy Tizuku especially head- Stone direct (Here, diode polarization electrons-Mus aso 7 evening power wings kiss) η wave 1L nuclear deflection L°- 4 Nufsonta was investigated, and a summary of the dead stones and ki tennuku of the Ishizukkai party research group 11
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Claims (1)

[Claims] The process of forming a coil conductor in a predetermined pattern on a substrate through a photosensitive resist mask with a predetermined film thickness is repeated multiple times to form a coil conductor laminated to a desired thickness on the substrate. 1. A method for manufacturing a magnetic head for magneto-optical recording, characterized by forming a magnetic head.