JPH03266239A - Sputtering method for magneto-optical disk - Google Patents

Abstract

PURPOSE:To allow easy formation in a large quantity by specifying the rotation and revolution ratio to the rotation of a 2nd base body when the rotation of a 1st base body is determined as revolution and reference. CONSTITUTION:The rotation and revolution ratio to the rotation of the 2nd base body 4 is set in a range of equation I when the rotation of the 1st base body 3 is determined as the revolution and reference. Namely, the rotation of the 2nd base body 4 is so set as to deviate slightly each at every one revolution. Consequently, periodic multilayerd films are formed on a disk substrate 5. Namely, the film by a film forming source 1 and a film forming source 2 are alternately formed by one layer each at every one revolution of the 1st base body 3. The periodic multilayered films laminated with the layers having the relatively significant influence of the film forming source 1 and the layers having the significant influence of the film forming source 2 are formed on the disk substrate 5. The easy production in a large quantity is possible in this way.

Description

[Detailed Description of the Invention] [Summary] The present invention provides a periodic multilayer film in which a magnetic film containing a large amount of rare earth metal and a magnetic film containing a large amount of transition metal are alternately laminated on a magneto-optical disk substrate by sputtering film formation as a recording layer. The purpose of the present invention is to provide a sputtering method for a magneto-optical disk having a periodic multilayer film that can be manufactured easily and in large quantities, with the objective of providing a sputtering method for a magneto-optical disk having a periodic multilayer film, and a rare earth material in which the recording layer is formed by sputtering. A first film forming source for a magnetic film containing a large amount of metal and a second film forming source for a magnetic film containing a large amount of transition metal are prepared, a rotatable first substrate;
A second base body that is located on the first base body and is rotatable; and a magneto-optical disk substrate that is held in the diurnal part of the second base body and is located opposite to the film forming source. have,
When the rotation of the first base body is used as a reference, the rotation and revolution ratio with respect to the rotation of the second base body is 1±0.2.3±.
Sputtering is performed on the magneto-optical disk substrate while the first and second substrates rotate and revolve within the range of 0.2.5±0.2.7±0.2.9±0.2. A sputtering method for a magneto-optical disk characterized by forming a multilayer film.

[Industrial application field]

The present invention relates to a method for sputtering a magneto-optical disk having a periodic multilayer film as a recording layer, in which a magnetic film rich in rare earth metals and a magnetic film rich in transition metals are alternately laminated on a magneto-optical disk substrate by sputtering film formation.

[Conventional technology]

A rare earth-transition metal magnetic film constituting a magneto-optical recording medium such as a rewritable magneto-optical disk is usually composed of a magnetic film of a single composition (ie, a single layer film). This rare earth-transition metal magnetic film has opto-magnetic properties (recording/erasing properties, C
/N ratio, frequency characteristics, etc.) will change.

For example, rare earths with a high transition metal composition relative to the compensation composition -
In the case of a single layer of a transition metal-based magnetic film (hereinafter referred to as a transition metal-rich film), a large Kerr rotation angle can be obtained, so C/
High N ratio. Furthermore, since the magnetization can be easily reversed, the recording sensitivity is also high. However, in terms of erasing characteristics, the large surrounding magnetization makes the recorded bits magnetostatically stable, making erasing difficult. Furthermore, since the magnetization M is large, unless the perpendicular anisotropy field is large, the perpendicular anisotropy is poor and stable recording bits cannot be obtained. Therefore, the frequency characteristics deteriorate.

Next, a rare earth-transition metal magnetic film (hereinafter referred to as a rare earth metal-rich film) that has a higher rare earth metal composition than the compensation composition.
In the case of a single-layer film, the Kerr rotation angle is smaller than that of a single-transfer metal-rich film, so the C/N ratio is poor. Furthermore, recording sensitivity is low and high laser power is required. On the other hand, since the magnetization M is small, erasing is easy and the frequency characteristics are good.

Therefore, in order to take advantage of the advantages of transition metal-rich films and rare earth metal-rich films and compensate for their shortcomings, a rare earth-transition metal magnetic film was proposed and implemented in which these two layers are laminated in such a way that they are exchange-coupled with each other. has been done.

For example, as a well-known technology of a film structure (periodic multilayer film) in which a transition metal-rich film and a rare earth metal-rich film are alternately laminated, there is a technique known as "magneto-optical recording medium" published in Japanese Patent Application Laid-open No. 63-311641. ``Photothermal magnetic recording medium'' is disclosed in Publication No. 63-282944.

[Problem to be solved by the invention]

By the way, the conventional method of forming a periodic multilayer film involves sputtering alternately from two film forming sources to a thickness of several tens of layers (
The film is formed by stacking thin films of the order of 10 angstroms, or sputtering is performed by adjusting the power using multiple film forming sources (for example,
(See "Magneto-Optical Recording Media" in Publication No. 311641).

However, the conventional sputtering method is
Thin films are sputtered alternately or by adjusting the power, and both require complicated sputtering equipment and manufacturing methods, and the stability (quality) of the periodic N film after sputtering is affected.
There was a problem.

The present invention was devised in view of the above-mentioned problems, and an object of the present invention is to provide a sputtering method for magneto-optical disks that can easily produce large quantities of periodic multilayer film magneto-optical disks.

[Means to solve the problem]

In a sputtering method for a magneto-optical disk having a periodic multilayer film in which a magnetic film containing a large amount of rare earth metal and a magnetic film containing a large amount of transition metal are alternately laminated as a recording layer of the magneto-optical disk, referring to FIG. - First film formation source 1 for a rare earth metal-rich magnetic film where the layer is formed by sputtering
and a second film forming source 2 for forming a magnetic film containing a large amount of transition metal, a rotatable first base 3, and a rotatable second base on the first base 3. 4 and this second base 4
A magneto-optical disk substrate (hereinafter referred to as disk substrate) held on the circumference of the disk and located opposite to the film-forming source 12
5, and when the rotation of the first base body 3 is taken as a reference as the revolution, the rotation-revolution ratio with respect to the rotation of the second base body 4 is 1±0.2.
．． 3 ± 0.2.5 ± 0.2.7 ± 0.2.9 ± 0.2, and while the first and second base bodies 3.4 rotate and revolve, they are placed on the disk substrate 5. It is characterized by forming a periodic multilayer film by sputtering.

[Function] If the rotation and revolution ratio of the first and second base bodies 3.4 holding the disk substrate 5 is used as in the present invention, there will be a part on the orbit of the disk substrate 5 as shown in the X section in FIG. , the first film formation 'a
A portion with a long residence time on L and a short portion such as the Y portion appear, and the rotation of the second base 4 moves so as to shift little by little with each revolution of the first base 3.

As a result, in one rotation (revolution) of the first base 3, a film formed by sputtering of the film forming source 1 (filled part) and a film formed by sputtering of the film forming source 2 (
The white part) is deposited one layer at a time, but due to the characteristics of the trajectory shown in Figure 3, the ratio (thickness) changes little by little, and the fourth
As shown in the figure, the layer (
1st layer A1, 3rd layer A2...) and layers that are largely influenced by the film formation source 2 (2nd layer B5, 4th layer B2...) are laminated alternately. It becomes a membrane.

By using a magnetic material containing a large amount of rare earth metals in the film forming source 1 and a magnetic material containing a large amount of transition metals in the film forming source 2, the periodic multilayer film is formed on the disk substrate 5, and the magneto-optical disk can be easily manufactured. and in large quantities.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a configuration diagram of a sputtering apparatus which is an embodiment of the present invention, FIG. 2 is an explanatory diagram of the arrangement of a base body that holds a disk substrate and the disk substrate, and FIG. 3 is a diagram showing the rotation and revolution of this base body and the disk substrate. FIG. 4 is an explanatory diagram of the film-formed portion according to the present invention, FIG. 5 is a table showing changes in the Tb composition of this film-formed portion, and FIG. 6 is a diagram showing the C/N ratio of this film-formed portion. It is a frequency characteristic diagram.

In FIG. 1, 1 is a first film forming source for forming a magnetic film rich in rare earths by sputtering the recording layer, 1a is a target having a large amount of rare earths, and 1b is this target layer t-1.
1c is a high frequency power source.

2 is a second film forming source for sputtering a magnetic film containing a large amount of transition metal; 2a is a target containing a large amount of transition metal; 2b
is a backing plate that holds this target 2a,
2C is a high frequency power source.

3 is a rotatable first base; 4 is a rotatable second base on the first base 3; 5 is fixed to the circumference of the second base 4; This is a disk substrate located at a position facing the film forming source 1.2.

In the first base body 3 and the second base body 4 that hold the disk substrate, when the rotation of the first base body 3 is used as a reference, the rotation-revolution ratio with respect to the rotation of the second base body 4 is set to 1±0. 2.3
Set within the range of ±0.2.5±0.2.7±0.2.9±0.2. In other words, the rotation of the second base body 4 is set so as to deviate little by little every revolution.

6 is a vacuum room, and the room 6 is kept in an argon (Ar) atmosphere 7 of several milliTorr. Further, in this chamber 6, a disk substrate 5, which is a film-attaching member, is arranged so as to face the target plates 1a, 2a held by the backing plates 1b, 2b.

Furthermore, a film forming source 1.2 and a disk substrate 5 (or
The first and second substrates 3.4) are separated by a wall, and this wall includes first and second targets la and 2a corresponding to the sputtering positions of the sputtering targets la and 2a sputtered from the film forming sources 1 and 2, respectively. Second opening 1d.

2d is drilled.

Then, this disk substrate 5 is connected to the ground wire, and the backing plates lb and 2b are connected to high frequency power supplies 1c and 2c of 10 to 13 pins.

With such a stappering device, the first and second base bodies 3.4 are rotated around their axis, the ratio of their rotation and revolution is set to, for example, about 3.2, and Ar ions are directed to the target la,
Collision with 2a and target la.

The molecules of 2a are repelled, and the repelled molecules of Ia and 2a are inserted into the respective first and second openings 1.
It is attached to the disk substrate 5 via d and 2d.

As in this invention, if the rotation-revolution ratio of the first and second base bodies 3.4 holding the disk substrate 5 is used, in the orbit of the disk substrate 5, the traveling direction of the first base body 3 and the second base body 3. If the direction of movement of the substrate 4 is reversed, the time spent above the first deposition source 1 or the second deposition source 2 will be longer (see section X in Figure 3), and the first substrate 3 and the second base 4 travel in the same direction, the residence time becomes shorter (Y part in Figure 3,
), the rotation of the second base body 4 moves so as to be slightly shifted every revolution.

As a result, a periodic multilayer film shown in FIG. 4 is formed on the disk substrate 5. In the figure, in order to make it easier to distinguish between the film from deposition source 1 and the film from deposition source 2, the film formed from deposition source 1 is shown as a shaded area, and the film formed from deposition source 2 is shown as a shaded area. The resulting film is shown in white.

That is, one layer of film is formed alternately by the film forming source 1 and the film forming source 2 for each revolution of the first substrate 3, but the ratio (thickness) varies depending on the characteristics of the orbit of the disk substrate 5 shown in FIG. changes little by little. As shown in FIG. 4, the layers (first layer AH1 third layer A2...
), and the layers that are greatly influenced by the deposition source 2 (second layer B1, fourth layer
A periodic multilayer film in which layers B2, . . . ) are laminated is formed on the disk substrate 5 to produce a magneto-optical disk.

In addition, a, b, c of the first layer A1 and 1 of the second layer B2
The fine layer structure indicated by , m, and n can be created by reducing the thickness of each layer to about 1 angstrom or less.
It can be eliminated.

Figure 5 shows 26.5% Tb in target 1a of film deposition source 1.
Using a rare earth metal-rich material (TbFeCo) containing
A transition metal-rich material (TbFeCo) containing 21.5% Tb is used in the target layer 2a of the film forming source 2 to form the first and second layers.
This figure shows the change in composition when sputtering is performed at a rotation-revolution ratio of about 3.2 on a substrate 3.4. According to this figure, along the film cross-sectional direction on the horizontal axis, a magnetic film containing a large amount of transition metal (Tb22.5%) and a magnetic film containing a large amount of rare earth metal (Tb
25.8%) are alternately laminated.

As is clear from the C/N ratio/frequency characteristic diagram of the film-formed portion shown in Fig. 6, the magnetic properties of the present invention are significantly higher than the conventional magnetic film with uniform rare earth-transition metal (see ■ in Fig. 6). film(
6), a high C/N ratio can be obtained because a transition metal-rich film with a large Kerr rotation angle is used in the layer read out by the Kerr effect.

In addition, since the transition metal-rich film with high recording sensitivity is heated, writing can be performed with low laser power, resulting in high recording sensitivity. Furthermore, since the transition metal-rich film and the rare earth metal-rich film are exchange-coupled, the overall magnetization Ms is small.
Therefore, the erasing power is small and the erasing sensitivity is high.

Furthermore, since the perpendicular anisotropy of the transition metal-rich film is ensured by exchange coupling, the frequency characteristics are good.

〔Effect of the invention〕

As explained above, the present invention provides a first film formation source for forming a magnetic film containing a large amount of rare earth elements and a second film formation source for a magnetic film containing a large amount of transition metals for forming a recording layer by sputtering,
a rotatable first base; on the first base;
and a rotatable second base body, and a disk substrate held on a circumferential portion of the second base body and located at a position facing the film forming source, and the rotation of the first base body revolves around the rotation of the first base body. When using this as a reference, the rotation and revolution ratios of the second base body are 1±0.2.360, 2.5±0.2.7 and 0.2.9.
By sputtering and forming a periodic multilayer film on a magneto-optical disk substrate while rotating the first and second substrates within the range of ±0.2, a magneto-optical disk with a periodic multilayer film is formed. It can be easily produced in large quantities.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a configuration diagram of a sputtering apparatus which is an embodiment of the present invention, Fig. 2 is an explanatory diagram of the arrangement of a base body that holds a disk substrate and a disk substrate, and Fig. 3 is a diagram showing this base body. FIG. 4 is an explanatory diagram of the rotational and rotational movements of the disk substrate, FIG. 4 is an explanatory diagram of the film forming part according to the present invention, FIG. 5 is a table showing changes in the Tb composition of this film forming part, and FIG. It is a C/N ratio/frequency characteristic diagram of a part. DESCRIPTION OF SYMBOLS 1... First film formation source, 1a... Target/nod, 1b... Backing plate, 1c... High frequency power supply, 1d... First opening, 2... Second deposition source. Film source, 2a... Target, 2b... Backing plate, 2c... High frequency power supply, 2d... Second opening, 3... First base, 4... Second base, 5... Disk board.

Claims (1)

[Scope of Claims] A method for sputtering a magneto-optical disk having a periodic multilayer film in which a magnetic film containing a large amount of rare earth metal and a magnetic film containing a large amount of transition metal are alternately laminated as a recording layer of the magneto-optical disk, comprising the steps of: A first film forming source (1) for forming a magnetic film containing a large amount of rare earth metal by sputtering and a second film forming source (2) for forming a magnetic film containing a large amount of transition metal are prepared. on the base (3) and the first base (3),
and a rotatable second base (4);
4), and is held at the circumferential portion of the film forming source (1), (2).
), and when the rotation of the first base body (3) is used as a reference, the rotation of the second base body (4) is the same as the rotation of the second base body (4). Rotation ratio 1±0
．． 2,3±0.2,5±0.2,7±0.2,9±0.
The periodic multilayer film is formed by sputtering on the magneto-optical disk substrate (5) while rotating and revolving the first and second substrates (3) and (4) in a range of 2. sputtering method for magneto-optical disks.