JPH0554327A - Pattern forming method and thin film magnetic head - Google Patents

Abstract

PURPOSE:To pattern a work, such as 'Permalloy(R)', with high accuracy by using a diamond film formed from a gaseous phase as a resist layer. CONSTITUTION:A resist pattern is transferred by an org. high-polymer layer 4 to a 1st layer 3 mainly consisting of diamond and the thin film to be worked is etched with this 1st layer 3 as a mask to form the prescribed pattern. The 1st layer 3 formed of the layer mainly consisting of the diamond has the resistance to high energy ions for ion milling, etc., higher by 5 to 10 times the resistance thereto of magnetic materials and zirconia and can be used as the sufficient etching mask even at a small film thickness. Finer track pitches are obtd. with higher accuracy in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finely processed surface and its method using a lithographic technique, and more particularly to a finely processed method by a physical sputtering method and a thin film magnetic head formed by this method.

[0002]

2. Description of the Related Art When conventional lithography techniques cannot be processed by wet etching or reactive dry etching, a resist pattern is formed on a thin film to be processed, and a material to be processed in a portion without a resist is removed by ion milling. Was there. This method is based on FeNi, CoTaZ
This method is indispensable for fine processing of magnetic materials such as r. For example, a phenol novolac resist was used for such etching. In the above ion milling, since the resist film is etched and consumed at the same time as the thin film to be processed, the etching resistance of the resist material is required. For example, ion milling using an Ar ion beam may require a resist film thickness that is at least twice as large as the film thickness to be processed, which causes a problem that the processing accuracy is not improved.

To solve the above problems, a thin and durable resist film is required, and along this line, JP-A-63-7643 is used.
Japanese Unexamined Patent Publication No. 8 discloses the use of a two-layer film composed of a carbonaceous thin film and an organic polymer thin film containing silicon. Further, Japanese Patent Laid-Open No. 63-168810 discloses that a magnetic material of a thin film magnetic head is patterned by using a two-layer film of sputtered carbon film and photoresist. Further, Japanese Unexamined Patent Publication No. 64-24049 discloses that a quartz substrate is etched using a film-shaped diamond pattern mask. The diamond layer can be formed, for example, by the vapor phase deposition method described in “Diamond Thin Film” by Nao Inuzuka, published by Sangyo Toshosha in 1987. Regarding the magnetic field microwave CVD method capable of depositing a diamond thin film at a relatively low temperature among the vapor phase deposition methods, Suzuki et al., Electronic Materials Journal, Vol. 28, No. 8, p51- 56, "Diamond synthesis by magnetic field plasma CVD method" is introduced.

[0004]

In order to reduce the thickness of the resist film in the above ion milling, it is necessary to slow the etching rate of the resist material. However, for example, in the method disclosed in JP-A-63-168810, the etching rate ratio between the sputtered carbon film (mask) and permalloy (processed film) is 1: 1 to 1: 1.
There are about five, which causes a problem that processing accuracy is restricted. An object of the present invention is to provide a pattern forming method and a thin film magnetic head capable of improving the processing accuracy by improving the problems of the above-mentioned conventional techniques.

[0005]

To solve the above problems, a film to be processed such as permalloy is patterned by ion milling using a resist layer of a diamond film formed from a vapor phase. Further, the magnetic track pattern of the thin film magnetic head is formed by the above method.

[0006]

According to the present invention, the resist pattern is transferred to the first layer mainly composed of diamond, the thin film to be processed is etched by using the first layer as a mask, and a predetermined pattern is accurately formed on the thin film to be processed. In this case, since the first layer is mainly formed of a diamond layer, it has a resistance to high-energy ions such as ion milling which is 5 to 10 times higher than that of a magnetic material or zirconia, and a thin film thickness provides a sufficient etching mask. be able to. Also, since it is easily etched by O ₂ plasma,
By combining with a resist containing Si, it becomes possible to easily form a highly precise pattern of a difficult-to-process material.

[0007]

1 is a process diagram of a pattern forming method according to the present invention. With this, for example, a magnetic track pattern of a thin film magnetic head can be formed. In the present invention, as shown in FIG. 1A, a permalloy film 2 laminated on a substrate 1 is processed by forming a pattern on a diamond layer 3 thereon. On the diamond layer 3 shown in FIG.
As shown in, for example, using a resist material described in Polymer Journal, Volume 463, No. 6 (1988), pages 460 to 463, an organic compound containing Si and containing high sensitivity to light or radiation is used. The molecular layer 4 is formed by a spin coat method (wet coating method). The organic polymer layer 4 can also be formed by a vapor deposition method such as a plasma polymerization method using an organic compound vapor or a vacuum vapor deposition method.

Then, as shown in FIG. 1 (c), a predetermined pattern is formed on the organic polymer layer 4 by a usual lithography (exposure, development) process. Then, as shown in FIG. 1D, a pattern is formed on the diamond layer 3 by a dry etching method using O ₂ using the pattern formed on the organic polymer layer 4 as a mask. At this time, the organic polymer layer 4
It is necessary that the etching rate of is less than the etching rate of the diamond layer 3. Reactive ion etching (RIE) having excellent anisotropy is desirable for the dry etching. Then, as shown in FIG. 1 (e), the organic polymer layer 4 is removed using a normal photoresist stripper. Then, as shown in FIG. 1F, the permalloy film 2 is formed by ion etching or ion milling with excellent anisotropy using the pattern of the diamond layer 3 as a mask.
Pattern. Finally, as shown in FIG.
_The diamond layer 3 is removed by dry etching using ₂ . If there is no problem, the diamond layer 3 is left as it is.

Next, a specific example of the process of the present invention will be described. Example 1 First, a silicon wafer having a diameter of 3 inches is used as a substrate 1 and a permalloy (NiF) having a thickness of 3 μm is formed thereon.
e) The film 2 is formed by the sputtering method. Next, the diamond layer 3 is formed by the following procedure. That is, the substrate 1 is placed on the electrodes of the magnetic field microwave CVD apparatus and
After heating to 00 ° C. and evacuating the vacuum chamber to a vacuum degree of 0.0001 Pa, a mixed gas of C ₂ H ₅ OH / H ₂ is supplied to keep the pressure at 100 mTorr. 2kW in this state
With the microwave power applied, plasma is generated 1
After holding for 0 hour, N ₂ purge is carried out, the pressure is returned to atmospheric pressure, and the substrate 1 is taken out to form a diamond layer 3 having a thickness of 0.6 μm. Then, an organic silicon resist (viscosity 15 cSt) was spin-coated on the diamond layer 3 to have a thickness of 1 μm.
A thick organic polymer layer 4 is formed. Then, 500 m of ultraviolet light (365 nm) was applied to the organic polymer layer 4 through a photomask having a line and space pattern of 5 μm.
The organic polymer layer 4 is patterned by exposing at an energy density of J / cm ² and immersing in a 0.7% aqueous solution of tetramethylammonium hydroxide for 2 minutes to develop (FIG. 1).
(C)).

Next, this substrate was placed in a high-frequency plasma apparatus, and after evacuation, O ₂ gas was introduced at a flow rate of 5 ml / min to 1.3 Pa, and 13.56 MHz, 200 W high-frequency power was discharged for 30 minutes. The O ₂ gas is stopped, the gas is evacuated and then returned to the atmospheric pressure. As a result, the pattern of the organic polymer layer 4 is transferred to the diamond layer 3 (FIG. 1 (d)). The removal of the permalloy film 2 in FIG. 1 (f) is performed as follows. The above substrate was installed in an ion milling apparatus, and ion milling was performed for 80 minutes under the conditions of an acceleration voltage of 700 V, a deceleration voltage of 200 V, an arc voltage of 80 V, an Ar flow rate of 15 ml / min, and an ion incident angle of 0 degree. To remove. Finally, the remaining diamond layer 3 is patterned (O ₂ etching) on this layer.
It is removed by the apparatus used for (FIG. 1 (g)). The pattern width of the permalloy film 2 formed by the above process is 5 ± 0.
It was in the range of 15 μm. 0.1 μm on average from this
It can be seen that a degree of pattern accuracy can be obtained.

Example 2 The organic polymer layer 4 was formed by plasma polymerization. The other steps are the same as those in the first embodiment. First, the substrate was placed on the ground-side electrode heated to 80 ° C. of the high-frequency plasma device used for patterning the diamond layer 3, the inside of the vacuum chamber was evacuated to 0.0001 Pa, and then methyl isopropenyl ketone and vinyl were added. A mixed gas of 1: 1 (flow rate ratio) of trimethylsilane was supplied at 5 ml per minute in terms of atmospheric pressure, and the exhaust speed was adjusted to maintain the internal pressure at 10 Pa. Next, high-frequency power of 13.56 MHz and 80 W was applied to the non-grounded electrode for 20 minutes for plasma polymerization to form an organic polymer layer 4 having a thickness of 0.3 μm. Next, this organic polymer layer 4 was irradiated with far ultraviolet rays of 254 nm at a density of 5000 mJ / cm ² through a quartz mask having a line-and-space pattern of 5 μm, and a 1: 4 (volume ratio) mixed solvent of water and isopropyl alcohol was mixed. To form a pattern. The pattern width of the permalloy film 2 formed by the pattern of the organic polymer layer 4 was within 4.9 ± 0.15 μm.

[Embodiment 3] FIG. 2A is a partial sectional view of a thin film magnetic head, and FIG. 2B is a top view of the thin film magnetic head. In this embodiment, the present invention is applied to width processing of a permalloy layer (magnetic track). Permalloy is sputtered to a thickness of 2.0 μm on the non-magnetic substrate 5, and the lower core layer 6 is formed by the photoetching technique. Then Al ₂ O ₃
Is formed to a thickness of 0.5 μm by sputtering, and the gap layer 7 is formed by using a photoetching technique.
Next, a polyimide resin (PIQ) is spin-coated, heat-cured, and patterned by photoetching technology to a thickness of 2
The insulating layer 8 has a thickness of μm. Next, Cu is formed in a thickness of 1.5 μm by a sputtering method, and is patterned into a spiral shape by a photoetching technique to form the coil 9.

An insulating film of polyimide resin having a thickness of 2.5 μm is formed thereon to form the insulating layer 10. Next, permalloy is sputtered to a thickness of 1.5 μm to form the upper core layer 11. The upper core layer 11 has a thickness of 0.3 μm.
Patterning is performed in the same manner as in Example 2 by using the diamond layer 3 and the 0.2 μm organic polymer layer 4 formed by plasma polymerization. The track width 12 at the tip of the upper core layer 11 shown in FIG. 2 (b) is within the range of 10 ± 0.5 μm, and the writing / reading characteristics should be sufficiently satisfactory for practical use. .. Finally, on the upper core layer 11, 1
A protective film is formed by sputtering Al ₂ O ₃ having a thickness of 0 μm.

[Comparative Example] In FIG. 1, when the diamond layer 3 is replaced with the conventional sputter carbon film 3 having a thickness of 2 μm, the track width 12 becomes 10 ± 1.0 μm, which is larger than that of the present invention. The variation doubled and sufficient processing accuracy could not be obtained.

[0015]

Since a diamond film having excellent resistance to ion milling is used, the resist film thickness can be greatly reduced.
It is possible to pattern a work material such as Malloy with high precision. Therefore, when the pattern forming method of the present invention is applied to the core portion forming the magnetic track of the thin film magnetic head, the track pitch can be made finer with high accuracy.

[Brief description of drawings]

FIG. 1 is a process diagram showing a pattern forming method according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view and a top view of a thin film magnetic head.

[Explanation of symbols] 1 substrate 2 permalloy film 3 diamond layer 4 organic polymer layer 5 non-magnetic substrate 6 lower core layer 7 gap layer 8 insulating layer 9 coil 10 insulating layer 11 upper core layer 12 track width

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Atsushi, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Ltd.

Claims (3)

[Claims] 1. A pattern forming method for removing a resist-free portion of a material to be processed on a surface of a substrate by physical sputtering, wherein a diamond film formed from a vapor phase is used as the resist layer. Forming method. 2. The workpiece according to claim 1, wherein the workpiece is a workpiece.
A pattern forming method characterized in that it is made of malloy. 3. A thin film magnetic head comprising a magnetic track of a permalloy layer which is patterned by using a diamond film formed from a vapor phase forming a magnetic track as a resist layer.