JPH1036963A - Sputtering device and formation of soft magnetic coating using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sputtering device capable of forming soft magnetic coating free from magnetic anisotropy and small in coercive force at the time of forming thin coating film by a sputtering method and to provide a method for forming soft magnetic coating film using this. SOLUTION: This device is provided with a target 5 arranged on a cathode part 3, a substrate 6 arranged opposite to the target 5 and a coating thickness correcting board 7 arranged between the target 5 and the substrate 6, and the coating thickness correcting board 7 has an opening part 7a having a shape by which the distribution of the coating film thickness is considered. Then, the opening part 7a has plural slits partitioned by walls in the approximately orthogonal direction to the substrate face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for forming a soft magnetic film constituting a thin film magnetic head using a magnetoresistive effect element, and a film forming apparatus used therefor.

[0002]

2. Description of the Related Art A magnetoresistive thin film magnetic head (hereinafter referred to as MR) which detects a resistance change of a magnetoresistive element film (hereinafter referred to as MR element) whose resistance changes by a signal magnetic field from a magnetic recording medium as a reproduction output. It is called a head.)
Has a feature that its reproduction output does not depend on the medium speed, and a high output can be obtained even when the medium speed is low. For example, it is attracting attention as a magnetic head for realizing a small-sized and large-capacity hard disk device. .

The MR head includes a lower shield made of a soft magnetic film, a lower gap layer made of a nonmagnetic material formed on the lower shield, an MR element formed on the lower gap layer, and an MR element formed on the lower gap layer. A first insulating layer formed thereon, a sense current conductor layer formed so as to partially overlap a rear end of the MR element, and a first insulating layer formed so as to cross over the MR element. A reproduction made of a non-magnetic material formed so as to be connected at the tip of the MR element, and a second insulating layer formed to cover the formed bias current conductor layer, the bias current conductor layer, and the MR element. It comprises an upper gap layer and an upper shield made of a soft magnetic film formed on the reproducing upper gap layer.

When reproducing a signal from a magnetic recording medium with such an MR head, a bias magnetic field is applied to the MR element by a current flowing through a bias current conductor layer, and a sense current conductor layer and an upper shield are applied to the MR element. Through,
A sense current is supplied to the MR element. Then, a signal from the magnetic recording medium is reproduced based on a change in resistance of the MR element depending on the magnitude of a signal magnetic field drawn into the MR element from the magnetic recording medium.

Incidentally, the MR element is generally formed by a sputtering method. The sputtering device forms a thin film on the substrate by sputtering ionized Ar gas and the like on the target plate placed on the cathode and depositing sputtered atoms jumping out of the target plate on the substrate placed on the anode. It is a device to do.

That is, in a sputtering apparatus, Ar gas is introduced as a sputtering gas into a high vacuum chamber to load a negative charge on a cathode, that is, a target plate. Then, an electric field is generated between the cathode and the anode as a pair of electrodes, glow discharge occurs, and ionized Ar gas in the plasma sputters the target plate. As a result, the sputtered atoms are knocked out of the target plate, and the sputtered atoms are deposited on the surface of the substrate arranged opposite to the target plate to form a thin film.

Here, sputtered atoms sputtered from the target plate tend to diverge in a non-uniform manner. As a result, the distribution of the sputtered atoms with respect to the substrate is biased and the thickness of the thin film attached to the substrate is reduced. Often become non-uniform. Therefore, in order to make the film thickness distribution of the thin film formed on the substrate uniform, between the target plate and the substrate,
A film thickness correction plate is provided. This film thickness correction plate 100
As shown in FIGS. 16A and 16B, an opening 100a having a shape considering the film thickness distribution is formed. Then, as shown in FIG. 17, the film thickness compensating plate 100 cuts off a part of the target plate 102 arranged on the cathode portion 101 so that the target plate 102 and the substrate holder 1 are cut off.
03 and the substrate 104 housed in the storage unit 03. Then, sputter atoms are deposited on the surface of the substrate 104 to form a thin film.

[0008]

However, in the sputtering apparatus provided with the film thickness correcting plate 100 as described above, generally, sputtered atoms jumping out of the target plate 102 form a stable film by increasing the film forming speed. for,
The trajectory is given by the magnetic flux generated from the erosion magnet mounted on the target plate 102. Therefore, the direction in which sputtered atoms fly out of the target plate 102 and pass through the opening 100a of the film thickness correction plate 100 is not constant, and the sputtered atoms
The angle at which it adheres to the surface 04 differs for each sputtered atom. This causes a problem that the magnetic anisotropy of the formed magnetic film is dispersed and a magnetic film having a large coercive force is formed.

In particular, the soft magnetic thin film constituting the thin film magnetic head is required to have a small magnetic anisotropy dispersion of the magnetic film and a small coercive force. When the coercive force of the magnetic film of the thin film magnetic head is large, the recorded magnetic tape is demagnetized due to the magnetization of the thin film magnetic head, thereby deteriorating the S / N ratio, increasing tape noise, or reducing the reproduction signal. There is a possibility that distortion may increase.

In order to suppress the dispersion of the magnetic anisotropy of the magnetic film, in the film forming step, the Ar gas pressure during the film forming is made as small as possible and the mean free step is made as long as possible.
It was also considered to make the angle of attachment to the substrate 104 constant, but the film formation efficiency was poor and sufficient effects could not be obtained.

Accordingly, the present invention has been made in view of the above-described problems, and when forming a thin film by a sputtering method, a soft magnetic film having no magnetic anisotropy and a small coercive force is formed. It is an object of the present invention to provide a sputtering apparatus capable of performing the above-described steps and a method for forming a soft magnetic film using the same.

[0012]

SUMMARY OF THE INVENTION A sputtering apparatus according to the present invention has been proposed to solve the above-mentioned problem, and has a target disposed on a cathode and a substrate disposed opposite the target. And a film thickness correction plate disposed between the target and the substrate, wherein the film thickness correction plate has an opening having a shape in consideration of the film thickness distribution, and the opening is formed on the substrate surface. On the other hand, it is characterized by comprising a plurality of slits partitioned by walls in a substantially orthogonal direction.

Further, the method for forming a soft magnetic film according to the present invention is characterized in that, when a soft magnetic film is formed by a sputtering method, a target disposed on a cathode and a substrate disposed opposite to the target are disposed. A thickness correction plate having a shape in consideration of the film thickness distribution, and a film thickness correction plate including a plurality of slits whose openings are partitioned by walls in a direction substantially perpendicular to the substrate surface; A soft magnetic film is formed on the substrate surface by passing the sputtered atoms protruding from the opening through the opening.

According to the sputtering apparatus of the present invention and the method of forming a soft magnetic thin film using the same, the scattering direction of the sputtered atoms jumping out of the target plate is limited by the slit of the film thickness compensator, and the sputtered atoms are reduced. Since it adheres to the substrate surface at a fixed angle, the thickness distribution of the formed soft magnetic film can be easily and accurately uniformized, and
A soft magnetic film having a small coercive force can be obtained while suppressing dispersion of magnetic anisotropy.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments to which the present invention is applied will be described below in detail with reference to the drawings.

As shown in FIG. 1, a sputtering apparatus to which the present invention is applied includes a high vacuum chamber 1 which is a film forming chamber, and a vacuum controller (not shown) for controlling a vacuum state in the high vacuum chamber 1. And a power source (not shown) for plasma discharge, and a sputter gas inlet 2 for supplying a sputter gas such as Ar into the high vacuum chamber 1. In the high vacuum chamber 1, a cathode unit 3 connected to a power supply by a power supply line and a substrate holder 4 opposed to the cathode unit 3 at a predetermined distance are arranged.

A target plate 5 is disposed on the cathode section 3, and an erosion magnet (not shown) is provided on the back of the target plate 5. On the substrate holder 4, a substrate 6, which is a film-forming target, is arranged. Cathode section 3
A shutter (not shown) for shutting off the target plate 5 at the time of pre-sputtering and a film thickness correction plate 7 for correcting the film thickness distribution are arranged between the substrate holder 4 and the substrate holder 4.

The cathode portion 3 and the substrate holder 4 constitute a pair of electrodes. The orbit of the sputtered atoms jumping out of the target plate 5 is given by the magnetic flux generated from the erosion magnet. The sputtered atoms passing through the portion 7a adhere to the surface of the substrate 6.

Here, the film thickness compensating plate 7 is shown in FIG.
As shown in FIG. 2, an opening 7a having a shape considering the film thickness distribution is provided. As shown in FIG. 2B, when viewed from the side, the opening 7a is partitioned into a wall substantially perpendicular to the substrate surface. Composed of a plurality of slits, for example, a width of 7 mm × 7 mm and a length of 10
It is formed in a lattice as an aggregate of slits of about mm. The shape of the opening 7a, the shape of the slit, and the form of the slit assembly are not particularly limited, and may be any as long as the direction in which the sputtered atoms protrude from the target plate 5 scatter can be limited.

Therefore, as shown in FIG. 3, the direction of the sputtered atoms jumping out of the target plate 5 is restricted by the plurality of slit-partitioned openings 7a, and is deposited on the surface of the substrate 6 at a constant angle. That is, only sputtered atoms scattered in a direction substantially perpendicular to the surface of the substrate 6 adhere to the surface of the substrate 6. The sputtering apparatus provided with the film thickness compensating plate 7 can easily and accurately equalize the film thickness distribution of the formed magnetic film, suppress the dispersion of magnetic anisotropy, and produce a soft film having a small coercive force. A magnetic film can be obtained.

Next, an embodiment in which a thin-film magnetic head is manufactured by using the above-described sputtering apparatus will be described.

First, as shown in FIG. 4, a substrate 11 made of an Altic material (Al ₂ O ₃ / Ti / C) is prepared.
An alumina film 12 is formed by sputtering. A lower shield 13 made of a soft magnetic material such as Fe-Ni is formed thereon as a magnetic path for reproduction by sputtering or plating.

Next, as shown in FIG. 5, the wiring pattern of the portion which does not overlap the lower layer
This is used as a lead electrode 14. Further, as shown in FIGS. 6 and 7, an alumina film 15 is formed thereon by sputtering, and then flattened and polished by using a mechanical polishing method, so that the lower shield 13 and the lead electrode 14 are exposed.

Next, on the lower shield 13, a reproducing lower gap layer 16 made of a nonmagnetic material that is electrically non-conductive such as alumina is formed by sputtering to improve the surface roughness and further reduce the edge. The intended chemical polishing is performed to form a contact hole on the lead electrode 14. Then, as shown in FIG. 8, an MR film made of a soft magnetic material such as Fe-Ni is formed as the MR element 17 on the lower reproducing gap layer 16 by sputtering. The reproducing lower gap layer 16 electrically insulates the lower part of the MR element 17 and forms a magnetic gap under the MR element 17.
On the other hand, the MR element 17 serves as a magnetic sensing part of the MR head, and is made of a material having a magnetoresistance effect. By this step, it is possible to form a structure having a predetermined gap length and a sufficient distance between the MR element 17 and the lower shield 13 after the depth “0” to reduce the interaction.

Next, as shown in FIG. 9, a first insulating layer 18 made of SiO ₂ or the like is formed on the MR element 17 by sputtering, and as shown in FIG. Part 1
7a and a contact hole are formed on the lead electrode 14. The first insulating layer 18 is formed for insulation between the MR element 17 and a conductor layer described later.

Then, as shown in FIG.
7 so as to be electrically connected to the rear end 1 of the MR element 17.
7a, a sense current conductor layer 19 is formed on
A bias current conductor layer is formed on the first insulating layer so as to cross over the MR element. The conductor layer 19 for the sense current and the conductor layer 20 for the bias current are made of Ti / Cu /
It is formed by depositing an electrode material made of Ti or the like by sputtering and processing it into a predetermined shape. Here, the sense current conductor layer 19 is for supplying a sense current to the MR element 17, and the bias current conductor layer 20 is provided.
Is for applying a bias magnetic field to the MR element 17.

Next, as shown in FIG. 12, a second insulation layer 21 is formed on the sense current conductor layer 19, the bias current conductor layer 20, and the first insulation layer 18 by sputtering. Then, as shown in FIG.
A contact hole is formed. The second insulating layer 21
Conductor layer 19 for sense current, conductor layer 20 for bias current,
And for insulation with an upper layer shield described later.

Next, as shown in FIG.
A reproducing upper gap layer 22 made of a metal film of Ti or the like is formed by sputtering on the front end portion 17b and the second insulating layer 21. After that, the upper shield 23 serving as a magnetic path during reproduction
Is formed similarly to the lower shield 13.

After the above steps, the MR head is completed by cutting it into a predetermined shape. However, since the MR head is a read-only magnetic head, a recording magnetic head may be laminated on the MR head in order to form a recording / reproducing magnetic head. Therefore, as shown in FIG.
A method for forming an inductive head using the upper shield 23 of the MR head as a recording magnetic core on the MR head will be described below.

The above MR head has an upper shield 2
Reference numeral 3 denotes a three-pole type functioning as a recording magnetic core. In the case of the four-pole type, an alumina film is formed on the upper shield 23 to separate the reproducing head from the recording head, and then a lower core is formed, and a recording magnetic head described later is formed thereon. Good.

When forming an inductive head as shown in FIG. 15, first, a recording gap layer 24 made of alumina or the like is formed by sputtering on an upper shield 23 functioning as one recording magnetic core. . And
A part of the recording gap layer 24 is removed to form a contact hole for achieving magnetic coupling between the upper shield 23 functioning as one recording magnetic core and the other recording magnetic core formed in a later step. I do.

Next, in order to insulate the upper shield 23 from the recording coil formed in a later step and obtain a flat coil formation surface, the planarizing layer 2 made of an organic material or the like is used.
5 is formed on the recording gap layer 24.

Next, a good conductive metal such as Cu is pattern-plated to form a recording coil 26 in a spiral shape on the flattening layer.

Next, on the recording coil 26, an organic material is used to insulate the recording coil 26 from a recording magnetic core formed in a later step and obtain a flat magnetic core forming surface. Is formed on the flattening layer 25 and the recording coil.

Next, a recording magnetic core 28 made of a soft magnetic material such as Fe-Ni is formed on the flattening layer 27 by sputtering or plating, and processed into a predetermined shape.

Next, a protective film (not shown) made of alumina or the like is formed on the recording magnetic core by sputtering, and then a terminal (not shown) for connecting an external circuit to the recording coil 26 is formed. ) Are formed.

Through the above steps, an inductive head in which the recording gap 24 is formed between the upper shield 23 functioning as a recording magnetic core and the recording magnetic core 28 is formed on the MR head, and the reproducing MR head is formed. Head and
A composite thin-film magnetic head for recording / reproducing including an inductive head for recording is completed.

By the way, in the above-described step, the above M
When a thin film made of a soft magnetic material such as the R element 17 is formed, the coercive force without magnetic anisotropy can be obtained by forming the soft magnetic film using a sputtering apparatus having the above-described thickness correction plate 7. The soft magnetic film having a small value can be formed.

For example, M
When forming the R element 17 to a thickness of 20 μm, for example, a soft magnetic material (Ni / Fe) is used for the target plate 5, the distance between the target plate 5 and the substrate 6 is about 40 mm, the target input power is 2 kW, and Ar gas is used. Flow rate 30 sccm, Ar
An MR film can be formed under a film forming condition of a gas pressure of 1.2 mT.

It is not necessary to use the film thickness compensating plate 7 in all of the sputtering devices used in the above-described steps, and the sputtering device can be used in combination with a conventionally used sputtering device. May be changed as appropriate.

The film thickness compensating plate 7 described above has a great effect when used when forming a soft magnetic film. That is, in the soft magnetic film obtained by the sputtering apparatus provided with the film thickness compensating plate 7, the scattering direction of the atoms ejected from the target plate 5 is limited by the slit, and the sputtered atoms adhere to the surface of the substrate 6 at a certain angle. Therefore, dispersion of magnetic anisotropy is suppressed. Therefore, according to the method for forming a soft magnetic thin film using the above-described sputtering apparatus, the film thickness distribution can be easily and accurately made uniform, and the dispersion of the magnetic anisotropy can be suppressed to reduce the coercive force. A magnetic film can be obtained, and the reproduction output characteristics of the thin-film magnetic head can be improved.

[0042]

As is clear from the above description, according to the sputtering apparatus of the present invention and the method of forming a soft magnetic thin film using the same, the direction of the scattering of the sputtered atoms jumping out of the target plate is determined by the film thickness. Limited by the slit of the compensator, sputtered atoms adhere to the substrate surface at a certain angle, so that the thickness distribution of the formed soft magnetic film can be easily and accurately uniformized, and the magnetic anisotropy can be improved. A soft magnetic film having a small coercive force can be obtained while suppressing the dispersion of properties.
Further, by using such a soft magnetic film for an MR element or the like, a thin-film magnetic head having excellent reproduction output characteristics can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a sputtering apparatus to which the present invention is applied.

FIG. 2A is a plan view of a film thickness correction plate to which the present invention is applied, and FIG. 2B is a side view of the film thickness correction plate.

FIG. 3 is a side view of a main part of a sputtering gas apparatus to which the present invention is applied.

FIG. 4 is a fragmentary cross-sectional view showing a step of forming a lower-layer shield.

FIG. 5 is a fragmentary cross-sectional view showing a step of forming a lead electrode;

FIG. 6 is a fragmentary cross-sectional view showing a step of forming an alumina film.

FIG. 7 is a fragmentary cross-sectional view showing a step in which planarization polishing of the alumina film is performed.

FIG. 8 is a fragmentary cross-sectional view showing a step of forming a reproducing lower gap layer and an MR element on a lower shield.

FIG. 9 is a fragmentary cross-sectional view showing a step of forming the first insulating film;

FIG. 10 is a fragmentary cross-sectional view showing a step of forming a contact hole with the MR element.

FIG. 11 is a fragmentary cross-sectional view showing a step of forming a conductor layer for sense current and a conductor layer for bias current.

FIG. 12 is a fragmentary cross-sectional view showing a step of forming a second insulating film;

FIG. 13 is a fragmentary cross-sectional view showing a step of forming a contact hole with the MR element.

FIG. 14 is a fragmentary cross-sectional view showing a step of forming a reproducing upper gap layer and an upper shield.

FIG. 15 is a cross-sectional view of a main part showing one configuration example of an inductive head formed on an MR head.

16A is a plan view of a film thickness correction plate of a conventional sputtering apparatus, and FIG. 16B is a side view of a main part of the film thickness correction plate.

FIG. 17 is a side view of a main part of a conventional sputtering apparatus.

[Explanation of symbols]

1 High vacuum chamber, 2 Sputter gas inlet, 3
Cathode, 4 substrate holder, 5 target plate, 6
Substrate, 7, thickness correction plate, 11 substrate, 12 alumina film, 13 lower shield, 14 lead electrode, 15 alumina film, 16 reproducing lower gap layer, 17 MR element,
18 first insulating layer, 19 conductive layer for sense current, 20
Conductor layer for bias current, 21 second insulating layer, 22
Reproducing upper gap layer, 23 upper shield, 24 recording gap layer, 25 flattening layer, 26 recording coil, 2
7 flattening layer, 28 magnetic core for recording

Claims (2)

[Claims] 1. A target comprising: a target disposed on a cathode; a substrate disposed opposite to the target; and a film thickness correction plate disposed between the target and the substrate. Is a sputtering apparatus characterized by having an opening having a shape in consideration of the film thickness distribution, and the opening comprising a plurality of slits separated by walls in a direction substantially perpendicular to the substrate surface. 2. When forming a soft magnetic film by a sputtering method, an opening having a shape considering a film thickness distribution is formed between a target disposed on a cathode and a substrate disposed opposite to the target. And a film thickness correction plate having a plurality of slits whose openings are partitioned by walls in a direction substantially orthogonal to the substrate surface, and allowing sputter atoms jumping out of the target plate to pass through the openings. Forming a soft magnetic film on a substrate surface by using the method.