JPH01173309A - Manufacture of thin-film magnetic head - Google Patents

Abstract

PURPOSE:To form an upper magnetic core layer with high accuracy by applying a coating type inorg. film on a resist pattern and calcining said film, then etching an upper core magnetic layer with the crosslinked pattern as a mask. CONSTITUTION:An underlying layer 5 and the magnetic core layer 6 are formed on a lower core layer at the time of forming the upper magnetic core layer. Said resist layer is exposed through a prescribed mask to form the resist pattern 7 and, for example, spin-on-glass coating agent produced by Chisso Co., Ltd. is applied as a coating type inorg. film 8 thereon and is calcined. The magnetic layer 6 is etched with the crosslinked resist pattern 7 as a mask to form the upper magnetic core layer. The inorg. film 8 does not collapse in the calcination stage and the pattern 7 after the calcination is crosslinked and does not collapse. The upper magnetic core layer is thus formed with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a thin film magnetic head which is excellent in high-density recording and is obtained by processing a thick magnetic core with high precision.

[Conventional technology]

The conventional wire-wound thin film magnetic head, as shown in Figure 4,
A lower magnetic core layer 2 is laminated on a substrate l. On the lower magnetic core layer 2, winding conductor layers 3 are disposed and covered with an insulating layer (not shown). moreover,
Upper magnetic core layers 4, 4 made of Ni-Fe, FeAJSi, Co-Zr, etc. are provided on the above-mentioned insulating layers, winding conductor layers 3, 3, and lower magnetic core layer 2. .

The magnetic core of the wire-wound thin-film magnetic head with the above structure has the ability to sufficiently magnetize high coercive force media, as the coercive force of magnetic recording media has been promoted with the recent increase in recording density. requested. Therefore, the upper magnetic core layers 4 tend to become thicker as the coercive force of the medium improves, and a magnetic thin film of about 5 to 30 μm is used.

A magnetic thin film having such a thickness is deposited on a predetermined upper magnetic core layer 4.
The conventional manufacturing method for thin film magnetic heads is as follows:
First, a lower magnetic core layer 2 is laminated on a substrate 1, and an insulating layer, a winding conductor layer 3, an insulating layer, a winding conductor layer 3, and an insulating layer are laminated on the top surface of the lower magnetic core layer 2 in this order. Stack layers. Next, a predetermined resist layer is patterned on the upper core magnetic layer. Thereafter, using the resist layer as a mask, the upper core magnetic layer is etched by sputter etching, ion milling, active ion etching, etc. to obtain the upper magnetic core layer 4.

[Problem that the invention seeks to solve]

However, the conventional method described above has a problem in that the upper magnetic core layer 4 cannot be formed with high precision.

That is, the upper magnetic core layer 4 is made of Ni-Fe as described above.
, FeAj! It is made of materials such as Si or Go-Zr, but methods for processing these materials with high precision include:
At present, the ion milling method is the most superior, and other methods are insufficient in terms of accuracy. However, since the method of forming the upper magnetic core layer 4 by the ion milling method is physical etching of Ar ions without any chemical reaction, for example, as shown in Table 1, photoresist as a mask material and other materials are used. The etching selectivity ratio with respect to the magnetic material described in 1 is approximately 1:1. Therefore,
In order to etch a magnetic film of about 2 to 30 μm,
The thickness of the resist pattern 7 shown in FIG. 5(a) is required to be approximately equal to or greater than the thickness of the magnetic material.

(Margin below) Table 1 The above resist pattern 7 was created by photolithography in the resist coating process (Sl
l), the exposure/development process (S12), and the post-baking process (S13), as shown in FIG. 5(a), are formed on the upper core magnetic layer 6 on the magnetic core underlayer 5. .

Immediately after development during the photolithography process, a resist film having a thick film thickness as described above, Yukiga 77. The angle is 7o to 8o, forming a square shape with an edge 7a.

However, due to the temperature increase during the post-baking process, approximately 1
When the temperature is 20° C. or higher, the viscosity decreases, and as shown in FIG. 2(b), the corners become rounded and the taper angle β becomes small. And the temperature will rise further
Alternatively, if time passes under the above temperature, the same figure (C
), the edge portion 7a of the resist pattern 7 begins to flow and the dimensions become irregular. The magnitude of this tendency depends on the thickness of the resist pattern 7, and is noticeable in the thick resist pattern 7 as described above. Such collapse of the shape of the resist pattern 7 can be seen in the same figure (c
In addition to the dimensional deviation shown in ), the change in the taper angle β of the edge portion 7a of the resist pattern 7 shown in FIG. 7B also has an adverse effect on the formation of the upper magnetic core layer 4.

On the other hand, the resist pattern 7 originally has a sixth pattern due to the dependence on the incident angle during etching using the ion milling method.
As shown in Figure (a), the edge portion 7a is highlighted and transferred onto the upper core magnetic layer 6. Then, as shown in FIG. 3B, the upper core magnetic layer 6 is processed by ion milling using the resist pattern 7 as a mask, and the upper magnetic core layer 4 is formed. The taper angle α of the upper magnetic core layer 4 is smaller than the taper angle β of the resist pattern 7. Furthermore, in actual etching, the rise in temperature of the substrate 1 during ion milling adds distortion as shown in FIG. 5(b). is an even smaller angle. Therefore, it becomes difficult to process the upper magnetic core layer 4 with high precision, and the cross-sectional area of the upper magnetic core layer 4 is reduced due to the taper of the edge portion 7a of the resist pattern 7. Here, in order to prevent the resist pattern 7 shown in FIGS. 5(b) and 5(c) from collapsing, it is possible to set the power input amount low during ion milling to suppress the temperature rise, but such a method In this case, the etching rate would be about 1/10 of the values shown in Table 1, so it would be completely impractical.

Therefore, in order to obtain a highly accurate upper magnetic core layer 4 by the ion milling method, it is necessary to crosslink the resist pattern 7 before performing ion milling so that the viscosity does not decrease due to temperature rise. For this purpose,
Conventionally, to prevent the resist pattern 7 from flowing, Dee
A method has been adopted in which the resist surface is crosslinked by irradiation with pUV (ultraviolet) light and then baked at a high temperature of about 160 to 250° C. (hereinafter referred to as UV cure).

However, with the above UV cure, if the resist pattern 7 has a relatively thin film thickness of around 1 μm, it is possible to crosslink it by high-temperature baking without destroying the shape of the resist pattern 7; When the thickness is 2 μm or more, the irradiation effect of Deep UV light is limited to only the surface layer, so if high temperature firing is performed,
Conversely, the resist pattern 7 will collapse.

[Means for solving problems]

In order to solve the above problems, the method for manufacturing a thin film magnetic head of the present invention uses a resist pattern patterned in a shape corresponding to the upper magnetic core layer as a mask to form an upper core magnetic layer for forming the upper magnetic core layer. In a method for manufacturing a thin film magnetic head in which an upper magnetic core layer is formed above a lower magnetic core layer by etching, a photoresist layer for pattern formation is exposed and developed to form a resist pattern, and this resist is After applying a coated inorganic film to the pattern, the resist pattern is fired to crosslink it, then the inorganic film on the resist pattern is removed, and the upper core magnetic layer is etched using this resist pattern as a mask. This is a configuration for forming a magnetic core layer.

[For production]

A photoresist layer is exposed and developed to form a resist pattern, and when a coated inorganic film is applied to this resist pattern, the coated inorganic film quickly dries and hardens, reinforcing and protecting the resist pattern from the outside. Therefore, in the next baking step, even if the viscosity of the resist pattern decreases and becomes soft due to a rise in temperature, the resist pattern will not lose its shape. After baking, the resist pattern is crosslinked and cured, so that even if the coated inorganic film is removed, the resist pattern does not lose its shape and maintains a predetermined shape. Thereby, when the upper core magnetic layer is etched using the above resist pattern as a mask, the upper magnetic core layer can be formed with high precision.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 to 4. In this embodiment, for convenience of explanation, FIG. 4 is used again.

The wire-wound thin film magnetic head manufactured by the method for manufacturing a thin film magnetic head according to the present invention has a substrate 1,
A lower magnetic core layer 2 is laminated thereon, and a winding conductor layer 3 is formed on the lower magnetic core layer 2 by an insulating layer (not shown).
3 is covered and disposed. Furthermore, upper magnetic core layers 4 made of Ni-Fe, FeAlSi, Co-Zr, etc. are provided on the above-mentioned insulating layer, the winding conductor layers 3, and the lower magnetic core layer 2. I'm there.

In the above structure, a method for forming the upper magnetic core layer 4 will be described below along the flowchart of FIG.

To form the upper magnetic core layer 4, first, as shown in FIG.
As shown in , a photoresist having a thickness of 2 to 40 μm corresponding to the thickness of the upper core magnetic layer 6 is coated on the upper core magnetic layer 6 by a method such as spin cording or dipping, and the photoresist layer is formed. form 9 (S
l).

Next, as shown in FIG. 2B, the photoresist layer 9 is exposed to light using a predetermined photomask and developed (S2>
, patterned into the shape of the upper magnetic core layer 4 to obtain a resist pattern 7. This resist pattern 7 is immersed in xylene to make the surface insoluble in ethyl alcohol.

This step is to prevent the resist pattern 7 from being damaged in the next step of coating the metal alkoxide hydrolyzate, since this metal alkoxide hydrolyzate generally uses alcohol as a solvent. Note that this step can be omitted if the resist pattern 7 is not damaged by the solvent.

Next, as shown in FIG.
is applied by a method such as a spin cord or dipping (S3). This coatable inorganic film 8 is one that hardens immediately after being coated, and for example, spin glass manufactured by Chisso ■ can be used. At this time, as shown in the figure, the coated inorganic film 8 tends to accumulate in the recesses 11 between the resist patterns 7, and is particularly thickly deposited on the edge portions 7a of the resist patterns 7. Thereafter, the viscosity of the resist pattern 7 does not decrease and the coated inorganic film 8 hardens.
The resist pattern 7 is baked, ie, post-baked, for about 30 minutes at a temperature of about .degree. C. (S4). Next, 160
Main baking of the resist pattern 7 is performed at ~250° C. for about 30 minutes (S5) to crosslink and harden the resist pattern 7. Although the viscosity of the resist pattern 7 decreases during this main baking process, the resist pattern 7 is not deformed because the periphery is covered with the hard coating-type inorganic film 8. Therefore, the resist pattern 7 is crosslinked while maintaining its square shape.

Next, the coated inorganic film 8 is removed using an etchant such as an ammonium fluoride solution (S7), as shown in FIG. 2D, to obtain a resist pattern 7 having a predetermined shape.

After etching the upper core magnetic layer 6 by ion milling using the resist pattern 7 as a mask, the resist pattern 7 is removed and the upper magnetic core layer 6 is etched into a predetermined shape as shown in FIG. get.

In the above configuration, the resist pattern 7 is fired while being covered with the coated inorganic film 8, so that it is protected by the hard coated inorganic film 8 during the firing process and is crosslinked without being shaved. Ru. Moreover, the coated inorganic film 8 applied to the resist pattern 7 is
7 and the edge portion 7 of the resist pattern 7
Since it accumulates in the resist pattern 7a, it does not peel off from the resist pattern 7, and in particular, the edge portion 7a of the resist pattern 7 is reliably protected.

Since the resist pattern 7 is crosslinked as described above, the resist pattern 7 does not lose its shape even when the temperature rises during the ion milling process. Therefore,
The upper magnetic core layer 4 formed by this resist pattern 7 can have a large taper angle α of the edge portion 4a, has a nearly rectangular shape, and can obtain high magnetic properties.

That is, when comparing the upper magnetic core layer 4 formed by the manufacturing method according to the present invention shown in FIG. 2 with the upper magnetic core layer 4 formed by the conventional manufacturing method shown in FIG. ,
Although the track width Tw is the same 50 μm1 and the core thickness TC is the same 10 μm, the cross-sectional area of the upper magnetic core layer 4 shown in FIG. 2 is 30% larger, and it is significantly superior in terms of efficiency. I understand. The above-mentioned difference in cross-sectional area becomes more pronounced as the track width Tw becomes narrower, and the thin-film magnetic head manufactured by the manufacturing method according to the present invention is advantageous for high-density recording.

〔Effect of the invention〕

As described above, the method for manufacturing a thin film magnetic head of the present invention includes:
An upper magnetic core layer is formed above the lower magnetic core layer by etching the upper core magnetic layer for forming the upper magnetic core layer using a resist pattern patterned in a shape corresponding to the upper magnetic core layer as a mask. In a method for manufacturing a thin film magnetic head, a photoresist layer for pattern formation is exposed and developed to form a resist pattern, a coated inorganic film is applied to the resist pattern, and the resist pattern is fired to crosslink it. Thereafter, the inorganic film on the resist pattern is removed, and the upper core magnetic layer is etched using the resist pattern as a mask to form the upper magnetic core layer.

Therefore, since the resist pattern can maintain a predetermined shape without causing wall warping, the upper magnetic core layer can be formed with high precision according to this resist pattern. Therefore, it is possible to obtain an upper magnetic core layer with a large cross-sectional area for the same track width, and the efficiency of the thin-film magnetic head can be greatly improved.
Effects such as being able to obtain a thin-film magnetic head suitable for high-density recording are achieved.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, in which (a) to (d) of FIG. 1 are cross-sectional views showing the process of forming a resist pattern, and FIG. 3 is a sectional view showing the upper magnetic core layer on the geological layer, FIG. 3 is a flowchart showing the process of forming a resist pattern, FIGS. 4 to 8 show conventional examples, and FIG. A perspective view showing the structure; FIGS. 5A to 5C are cross-sectional views showing the deformation process of the resist pattern due to temperature rise;
a) is a cross-sectional view showing the resist pattern transferred onto the upper core magnetic layer, FIG. 7(b) is a cross-sectional view showing the upper magnetic core layer formed by the resist pattern, and FIG.
FIG. 8 is a cross-sectional view showing an actual upper magnetic core layer having a smaller taper angle α than the upper magnetic core layer shown in FIG. 8B, and a flowchart showing the process of forming a resist pattern. 1 is a substrate, 2 is a lower magnetic core layer, 3 is a winding conductor layer, 4 is an upper magnetic core layer, 4a is an edge portion, 5 is a magnetic core base layer, 6 is an upper core magnetic layer, 7 is a resist pattern, 7a 8 is an edge portion, 8 is a coated inorganic film, and 9 is a photoresist layer. Fig. 1 (a) h 1 Fig. (C) Fig. 1 (b) Fig. 1 (d) Fig. 2 ) Figure 8 To ion millimeter

Claims (1)

[Claims] 1. By etching the upper core magnetic layer for forming the upper magnetic core layer using a resist pattern patterned in a shape corresponding to the upper magnetic core layer as a mask, above the lower magnetic core layer, In a method for manufacturing a thin-film magnetic head in which an upper magnetic core layer is formed, a photoresist layer for pattern formation is exposed and developed to form a resist pattern, a coatable inorganic film is applied to this resist pattern, and then a resist pattern is formed. A thin film magnetic film characterized in that the inorganic film on the resist pattern is removed, and the upper core magnetic layer is etched using the resist pattern as a mask to form the upper magnetic core layer. Head manufacturing method.