JPH11120637A - Deposition method and production of optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deposition method capable of easily forming films having a laminar structure simply by only using one target and mounting the target on a single substrate type sputtering apparatus and a process for producing an optical disk by using the same. SOLUTION: At the time of repetitively depositing basic layers laminated with plural layers consisting of different materials on a substrate 21, the one target 11 divided with the materials constituting the respective layers of the basic layers circumferentially to regions 11a, 11b by each of the respective materials is arranged to face the substrate 21 and sputtering is executed while the substrate 21 and the target 11 are relatively rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a film by a sputtering method and a method for manufacturing an optical disk.

[0002]

2. Description of the Related Art In recent years, optical disks have attracted attention as recording media for audio and computers, since they can record information at high density and reproduce at high speed. Among such optical disks, there are various types of recording systems. Among them, a magneto-optical type optical disk (magneto-optical disk) that can perform information rewriting and overwrite recording is of particular interest. .

In this magneto-optical disk, a memory film for recording information is composed of a magnetic material (perpendicular magnetization film) whose magnetization is oriented perpendicular to the film surface. The information is expressed in the direction of. Such a memory film is generally composed of a uniform alloy film of a rare earth metal and a transition metal. Here, the formation of the memory film is performed using a known single-wafer sputtering apparatus. In this case, in the single-wafer sputtering apparatus, one alloy target in which a rare earth metal and a transition metal are mixed according to the composition of the memory film is arranged to face the substrate.

Meanwhile, in a magneto-optical disk, it is necessary to further increase the coercive force of a memory film in order to enhance the stability as an information recording medium. Therefore,
In recent years, it has been proposed that the memory film has a layer structure (multilayer) in which a layer mainly composed of a rare earth metal and a layer mainly composed of a transition metal are alternately and repeatedly laminated.

When the memory film has a layer structure as described above, the coercive force of the memory film is higher than the coercive force of the memory film of a uniform alloy. However, a memory film having a layer structure could not be formed using a single-wafer sputtering apparatus. This is because a single alloy target placed in a single-wafer sputtering apparatus cannot separately and repeatedly laminate a layer mainly composed of a rare earth metal and a layer mainly composed of a transition metal.

Therefore, a co-sputtering apparatus has conventionally been used to form a memory film having a layer structure. FIG. 6 shows a simultaneous sputtering apparatus 60 for forming a memory film having a layer structure. In the simultaneous sputtering apparatus 60, a rare earth metal target 61 and a transition metal target 62 are separately arranged. Also, as shown in FIG.
Attached to a holder 64 that rotates about 0,
It is revolved by the rotation of the holder 64.

Therefore, at the time of sputtering, the substrate 6
As the orbit 3 revolves, the substrate 63 alternately faces the rare earth metal target 61 and the transition metal target 62. As a result, a layer mainly composed of a rare earth metal and a layer mainly composed of a transition metal are alternately and repeatedly laminated on the substrate 63. As described above, conventionally, a memory film having a layered structure has been formed by the simultaneous sputtering apparatus 60.

[0008]

However, as described above, in a simultaneous sputtering apparatus for forming a memory film having a layer structure, a plurality of targets are separately arranged inside the apparatus, and a cathode and a power Since it is necessary to provide a plurality of optical discs, the apparatus configuration is complicated and expensive, and the manufacturing cost of the magneto-optical disk has to be increased.

Further, in general, during sputtering, it is necessary to evacuate the inside of the apparatus, so that the apparatus itself is desirably small. However, in the simultaneous sputtering apparatus in which a plurality of targets and the like are arranged as described above, the apparatus itself becomes large, so that it takes time to reduce the vacuum and the throughput is reduced.

An object of the present invention is to provide a film forming method which can easily form a film having a layer structure simply by using a single target and mounting the same on a single-wafer sputtering apparatus, and an optical disk using the same. It is to provide a manufacturing method of.

[0011]

According to the first aspect of the present invention, when a basic layer in which a plurality of layers made of different materials are laminated is repeatedly formed on a substrate, each of the basic layers is formed. One target in which a substance is divided into regions in the circumferential direction for each substance is arranged to face the substrate, and sputtering is performed while rotating the substrate and the target relatively.

According to a second aspect of the present invention, in the film forming method according to the first aspect, the target is divided into regions according to the number of substances constituting the basic layer, and each divided region of the target is divided into the basic layer. Is composed of the substances constituting the above. According to a third aspect of the present invention, in the film forming method of the second aspect, the area ratio of each region of the target is determined by the ratio of the thickness of each layer constituting the basic layer to the ratio of the sputtering rate of the material of each layer. Is determined based on the above.

According to a fourth aspect of the present invention, there is provided a method of manufacturing an optical disk using the film forming method according to any one of the first to third aspects.
One region is composed of a rare earth metal, and the other region is composed of a transition metal.

According to a fifth aspect of the present invention, in the method of manufacturing an optical disk according to the fourth aspect, the rare earth metal is terbium and the transition metal is iron or an alloy of iron and cobalt. The invention according to claim 6 is the invention according to claim 5
In the method of manufacturing an optical disk described in the above item, each layer of the basic layer is formed on the substrate of the optical disk to a thickness of more than 0.2 nm
It grows to a predetermined thickness smaller than nm.

According to a seventh aspect of the present invention, in the film forming method of the first aspect, when the sputtering rate is R, the relative rotation speed between the substrate and the target is R
/ 6 <relative rotation speed <R / 0.4.

(Function) According to the film forming method of the first aspect, sputtering is performed using a single-wafer sputtering apparatus while rotating one target and the substrate relatively, so that the sputtering method is performed on the substrate. A plurality of layers (basic layers) made of different substances can be repeatedly formed.

According to the film forming method of the present invention, one basic layer composed of a plurality of layers made of different substances is laminated on the substrate each time the target and the substrate are rotated by one revolution. You. Then, by continuously performing the relative rotation, the basic layer can be repeatedly formed on the substrate. According to the film forming method of the third aspect, even if the sputter rates are different from each other, it is possible to form a basic layer in which a plurality of layers made of these different materials are stacked at a desired thickness.

According to the optical disk manufacturing method of the present invention, the sputtering is performed while rotating one target and the substrate relative to each other by using the single-wafer sputtering apparatus, so that at least one target is formed on the substrate. A basic layer in which one rare earth metal layer and one transition metal layer are stacked can be repeatedly formed.

According to a fifth aspect of the present invention, a terbium layer and an alloy layer of iron and cobalt are alternately and repeatedly laminated using a single-wafer sputtering apparatus, or terbium. A magnetic film (for example, a memory film) having a layered structure in which a layer of iron and a layer of iron are alternately and repeatedly laminated can be formed on the substrate.
According to the optical disk manufacturing method of the sixth aspect, the base layer in which each layer having a thickness greater than 0.2 nm and smaller than 3 nm is repeated using a single-wafer sputtering apparatus to form a magnetic film ( For example, a memory film is formed on the substrate.

According to the film forming method of the present invention, when the sputtering rate is R, one target and the substrate are rotated at a relative rotational speed satisfying R / 6 <relative rotational speed <R / 0.4. By performing the sputtering while rotating the substrate, a plurality of layers (basic layers) made of different substances can be repeatedly formed on the substrate.

[0021]

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

(First Embodiment) This first embodiment corresponds to claims 1 to 7. FIG. 1 shows a single-wafer sputtering apparatus 10 and a target 1 according to a first embodiment.
FIG. 2 is an explanatory diagram showing a configuration of No. 1. Here, prior to the description of the single-wafer sputtering apparatus 10, the optical disc 20 on which the memory film 23 formed by the single-wafer sputtering apparatus 10 is formed will be described with reference to FIGS.

As shown in FIG. 2, the optical disk 20 has a lower protective film 22 and a memory film 2 on a substrate 21.
3 and an upper protective film 24 are sequentially stacked.
The memory film 23 is a film on which information is recorded, and is protected by the lower protective film 22 and the upper protective film 24.

In particular, the memory film 23 of the optical disc 20
As shown in FIG. 3, a layer 23-1 of terbium (Tb) as a rare earth metal and a layer 23-2 of an alloy of iron and cobalt (FeCo) as a transition metal are alternately repeated. It has a laminated layer structure. Here, the combination of the two adjacent layers 23-1 and 23-2 is the base layer 23.
a.

Next, the memory film 23 having a layer structure is
A single-wafer sputtering apparatus 10 to be formed thereon and a target 11 mounted thereon will be described with reference to FIG. As shown in FIG. 1, one target 11 is arranged in the single-wafer sputtering apparatus 10.

The target 11 is made of the base layer 2 described above.
The material constituting 3a is divided into regions in the circumferential direction for each material. In the first embodiment, the basic layer 23
The substances constituting a are Tb alone and an FeCo alloy. As described above, the target 11 is divided into two fan-shaped regions 11a and 11b in the circumferential direction because there are two kinds of substances constituting the basic layer 23a. One region 11a is composed of Tb alone of the basic layer 23a, and the other region 11b is composed of an FeCo alloy.

Here, each area 11a of the target 11
The area ratio of the center angles θ1a and θ1b (θ
1a: θ1b). Ratio θ1 representing this area ratio
a: θ1b is a ratio (D11: D11: D11: D12) of the two layers 23-1, 23-2 constituting the basic layer 23a.
D12) and Tb sputter rate S11 and FeCo under the same conditions (ion energy, incident angle, etc.)
Is determined based on the ratio (S11: S12) to the sputtering rate S12. That is, θ1a: θ1b = D11
/ S11: D12 / S12.

In the first embodiment, each area 11a, 11b
Is a ratio D11: D1 of the thicknesses of the two layers 23-1 and 23-2 constituting the basic layer 23a.
2 is set to be approximately 1: 1. By the way, if the thickness ratio D11: D12 of the layers 23-1 and 23-2 is set to approximately 1: 1 as described above, the ratio of the sputter rate of the material constituting each of the layers 23-1 and 23-2 is determined. In consideration of S11: S12, the area ratio is determined to be approximately 1: 3 (center angle θ1
a is approximately 90 degrees, and the central angle θ1b is approximately 270 degrees).

The target 11 in which the area ratio of each of the regions 11a and 11b is determined as described above is coaxially arranged facing the substrate 21 in the single-wafer sputtering apparatus 10, as shown in FIG. In the single-wafer sputtering apparatus 10 in which the targets 11 are arranged as described above, a predetermined power is supplied to the targets 11 during sputtering. In addition, the substrate 21 is rotated at a predetermined rotational speed about the axis L10 during sputtering.

Here, the power of the electric power supplied to the target 11 and the rotation speed of the substrate 21 are controlled by the thicknesses D11 and D12 of the two layers 23-1 and 23-2 constituting the basic layer 23a.
Is determined according to. For example, if the thicknesses D11 and D12 are 0.6 nm, the power may be 950 W and the number of rotations may be 40 rpm. Further, the inside of the single-wafer sputtering apparatus 10 temporarily
It is evacuated until the pressure becomes 0 ^-6 Torr or less.
Argon gas is introduced and maintained at 5 × 10 ⁻³ Torr.

Such a single-wafer sputtering apparatus 10
While rotating the substrate 21 at the above rotation speed (40 rpm) with respect to the target 11, the predetermined power (950
When the sputtering is performed in the step W), the Tb layer 23-1 and the FeCo layer 23-2 are laminated on the substrate 21 each time the substrate 21 rotates once, thereby forming one basic layer 23a ( (Fig. 2).

As described above, the single-wafer sputtering apparatus 1
The central angle θ1a of the region 11a of the target 11 disposed in the area 0 is approximately 90 degrees, and the central angle θ1b of the region 11b is approximately 27.
By setting it to 0 degree, the thickness ratio D1 of the two layers 23-1 and 23-2 made of materials having different sputter rates from each other is obtained.
1: D12 can be approximately 1: 1. Further, as described above, the power of the power input to the target 11 is set to 9
By setting the rotation speed of the substrate 21 to 50 W and 40 rpm,
Both the thickness D11 of the Tb layer 23-1 and the thickness D12 of the FeCo layer 23-2 can be approximately 0.6 nm.

The ratio D1 of the thickness of each of the layers 23-1 and 23-2 is represented by D1.
The basic layer 23a in which the ratio of 1: D12 is approximately 1: 1 (the thickness is both 0.6 nm) is repeatedly laminated on the substrate 21 by continuing the rotation of the substrate 21 (FIG. 3), and the memory having the layer structure is formed. A film 23 is formed. The formation of the memory film 23 having this layer structure is performed until the film thickness becomes 50 nm.
The memory film 23 having the above-described layer structure (the layer 23 of Tb)
-1 and the thickness ratio D11: D12 of the FeCo layer 23-2 is approximately 1: 1), the composition ratio is macroscopically expressed in atomic percentage, Tb is 20 atomic%, and Fe is 64 atomic%. Atomic%, C
o is 16 atomic%.

Further, the lower protective film 22 and the upper protective film 24 protecting the memory film 23 having the above-mentioned layer structure (FIG. 2).
Are silicon nitride films, each having a thickness of 70 nm. The lower protective film 22 and the upper protective film 24 are formed by a well-known reactive sputtering method using a single-wafer sputtering apparatus as in the case of the memory film 23 described above.

The substrate 21 is made of 2P (photo-polymeriz
ation) method glass substrate (diameter 86mm)
It is. As described above, in the first embodiment, Tb
Is performed while rotating the substrate 21 on one target 11 divided into two regions, that is, the region 11a of FeCo and the region 11b of FeCo. Membrane 23
Can be formed.

The memory film 23 having a layer structure formed as described above can have not only the characteristic that the magnetization is oriented vertically like a uniform alloy but also the characteristic that the coercive force is high. . In addition, in the single-wafer sputtering apparatus 10 for forming the memory film 23 having a layer structure, the number of targets 11 disposed therein is one, so that the apparatus configuration is simple, and the memory film 23 having a layer structure is formed. The cost for film formation can be kept low.

The single-wafer sputtering apparatus 10 for forming the memory film 23 having a layered structure has a structure in which one target 11 is arranged as described above, so that the apparatus itself is small. Therefore, the inside of the apparatus can be evacuated in a short time, and the throughput can be improved. Further, in the first embodiment, since the substrate 21 and the target 11 are coaxially arranged, there is no occurrence of composition unevenness in the memory film 23 having a layer structure.

In the first embodiment, in the memory film 23 having a layer structure, each of the layers 23-
Although the example in which the thicknesses D11 and D12 of 1, 23-2 are both 0.6 nm has been described, these thicknesses D11 and D12
Can be set to any value within the range greater than 0.2 nm and less than 3 nm. This is for each thickness D1
This is because if 1,1 and D12 are within the above range, the memory film 23 having a layer structure becomes a perpendicular magnetization film having a high coercive force. In order to set the thicknesses D11 and D12 to arbitrary values,
The power of the electric power supplied to the target 11 or the substrate 2
The number of rotations of 1 may be set to a desired value. Incidentally, the minimum value 0.2 of the thicknesses D11 and D12 of the layers 23-1 and 23-2 is 0.2.
nm corresponds to the thickness of one atom constituting each of the layers 23-1 and 23-2.

Further, in the first embodiment, in the memory film 23 having a layer structure, the thickness ratio D of each of the layers 23-1 and 23-2 is D.
11: D12 has been described with an example of approximately 1: 1.
The thickness ratio D11: D12 is determined according to the composition ratio of the memory film to be formed. Also in this case, each of the thicknesses D11 and D12 is set to an arbitrary value within a range larger than 0.2 nm and smaller than 3 nm. It should be noted that the thickness ratio D11: D12 corresponds to each region 11a, 1
It can be freely determined by the area ratio of 1b (ratio θ1a: θ1b).

Further, in the first embodiment, when forming the memory film 23 having a layer structure, the substrate 21 is rotated with respect to the target 11 so that the substrate 21 and the target 11 are rotated relatively. Alternatively, the substrate 21 may be fixed, and the target 11 may be rotated with respect to the substrate 21. Further, a magnet may be provided on the back surface of the target 11 of the first embodiment, and the memory film 23 may be formed by a rotary magnet method in which sputtering is performed while rotating the magnet. In this case, the entire surface of the target larger than the substrate is uniformly used for sputtering, and the layer 2 forming the basic layer 23a of the memory film 23 is formed.
The thickness of 3-1 and 23-2 can be made more uniform.

Further, in the first embodiment, when forming the memory film 23 having a layer structure, the target 11 in which Tb alone and the FeCo alloy are divided into regions is used. And a powder obtained by mixing Fe and Co into a desired composition are filled in a predetermined mold so as to form a sector having a predetermined central angle, and then heated under pressure (known hot pressing). It is made with.
In this case, instead of powder, Tb and FeCo alloys may be combined in a sector-shaped solid combination.

(Second Embodiment) Next, a second embodiment will be described. This second embodiment also corresponds to claims 1 to 7. The second embodiment is for forming the memory film 33 having the layer structure shown in FIG. 4. The target 31 shown in FIG. 5 is mounted on the single-wafer sputtering apparatus 10 of the first embodiment. The film is formed.

As shown in FIG. 4, the memory film 33 formed according to the second embodiment has a Tb layer 33-1,
It has a layer structure in which three layers of an Fe layer 33-2 and a Co layer 33-3 are alternately and repeatedly laminated. That is, the combination of the three adjacent layers 33-1 to 33-3 becomes the basic layer 33a. In the second embodiment, the material forming the basic layer 33a is Tb, Fe, Co.
There are three types.

In forming the memory film 33 having such a layer structure, a target 31 (FIG. 5) is used instead of the target 11 of the single-wafer sputtering apparatus 10 (FIG. 1) of the first embodiment. Be placed. The target 31 of the second embodiment is divided into three fan-shaped regions 31a, 31b, and 31c in the circumferential direction. in this case,
The region 31a is composed of only Tb of the basic layer 33a, the region 31b is composed of Fe alone, and the region 31c is composed of Co alone.

Here, each region 31a of the target 31
The area ratio of 31b, 31c (represented by θ3a: θ3b: θ3c) is determined by the layers 33-1 and 33- constituting the basic layer 33a.
2, the ratio of the thicknesses D31, D32, D33 of 33-3, and the T under the same conditions (ion energy, incident angle, etc.)
b, Fe, Co sputtering rates S31, S32, S3
Determined based on a ratio of three.

In the second embodiment, the area ratio (θ
3a: θ3b: θ3c) are the thickness D31 of the rare earth metal layer (Tb layer 33-1) constituting the basic layer 33a, the transition metal layer (Fe layer 33-2, Co layer 33-3). ) Thickness D
The ratio with 32 + D33 is determined to be approximately 1: 1. That is, θ3a: θ3b: θ3c = D31 / S3
1: D32 / S32: D33 / S33.

By the way, if the thickness ratio D31: D32 + D33 of the rare earth metal layer and the transition metal layer is approximately 1: 1 as described above, each of the layers 33-1, 33-2, 33-3.
The ratio of the sputter rate of the material constituting S31: S32:
In view of S33, the area ratio of each region 31a, 31b, 31c is determined to be approximately 9: 22: 5 (θ3a = 90 degrees, θ
3b = 220 degrees, θ3c = 50 degrees).

In the single-wafer sputtering apparatus 10 equipped with such a target 31, sputtering is continuously performed at a predetermined power (950 W) while rotating the substrate at a predetermined rotation speed (40 rpm) with respect to the target 31. When performed, the basic layer 33 composed of three layers 33-1 to 33-3
a is repeatedly laminated on the substrate as in the first embodiment (FIG. 4), and the memory film 33 having a layer structure is formed.

Here, in the second embodiment, the target 3
1, the central angle θ3a of the region 31a = 90 degrees, the central angle θ3b of the region 31b = 220 degrees, the central angle θ3c of the region 31c =
By setting the input power to 950 W and the rotation speed of the substrate to 40 rpm at 50 degrees, the three layers 33-1 to 33-3 made of materials having different sputter rates from each other,
The thickness D31 of the rare earth metal layer and the thickness D of the transition metal layer
32 + D33 can be set to approximately 0.6 nm.

The memory film 33 having the above-mentioned layer structure is used.
Is also formed until the film thickness becomes 50 nm. The composition ratio at this time is macroscopically similar to the composition ratio of the memory film 23 formed according to the first embodiment.
Fe is 64 atomic% and Co is 16 atomic%. As described above, in the second embodiment, the region 31 of Tb
Since sputtering is performed while rotating the substrate on one target 31 divided into three regions a, Fe region 31b, and Co region 31b, the single-wafer sputtering apparatus is similar to the first embodiment. Can be used to form the memory film 33 having a layer structure.

The memory film 33 having a layer structure formed in this manner can have not only the characteristic that the magnetization is vertically oriented as in the case of the uniform alloy but also the characteristic that the coercive force is high. . In the second embodiment, in the memory film 33 having a layered structure, the thickness D31 of the rare earth metal forming the base layer 33a and the thickness D3 of the transition metal
2 + D33 is 0.6 nm, but the thickness D31, D3 of each layer 33-1 33-2 33-3 is described.
2, D33 can be set to any value within a range greater than 0.2 nm and less than 3 nm. This is because, as in the first embodiment, if each of the thicknesses D31, D32, and D33 is within the above range, the memory film 33 having the layer structure becomes
This is because a perpendicular magnetization film having a high coercive force is obtained. In order to set the thicknesses D31, D32, and D33 to arbitrary values, the power supplied to the target 31 and the number of rotations of the substrate may be set to desired values, as in the first embodiment.

Further, in the second embodiment, in the memory film 33 having the layer structure, the thickness D31 of the rare earth metal layer
Although an example in which the ratio of the transition metal layer to the thickness D32 + D33 is approximately 1: 1 has been described, this thickness ratio D31: D3 is used.
2 + D33 is determined according to the composition ratio of the memory film to be formed. Also in this case, similarly to the first embodiment, each of the thicknesses D31, D32, and D33 is larger than 0.2 nm and 3
It is set to an arbitrary value within a range smaller than nm. In addition,
The thickness ratio D31: D32: D33 is determined by the area ratio of each region 31a, 31b, 31c of the target 31 (ratio θ3a: θ
3b: θ3c).

In the first and second embodiments described above, an optical disk in which one magnetic film (ie, a memory film) is formed on a substrate is taken as an example, and the memory film is formed in a layer structure. Although the case has been described, in an optical disk in which a plurality of magnetic films are formed on a substrate (for example, an optical disk of a magnetic super-resolution reproducing method or a direct overwrite recording method), a memory film or another magnetic film (for example, a recording film) is used. The present invention is also applicable to a case where a film, an initialization film, and a switching film) are formed in a layered structure.

In the above-described embodiment, an example was described in which a magnetic film of TbFeCo having a composition ratio of 20 atomic% of Tb, 64 atomic% of Fe, and 16 atomic% of Co was formed in a layer structure. Tb having a different composition ratio from the above embodiment
A magnetic film of FeCo can be formed in a layer structure. In this case, the area ratio of each region of the target may be determined according to the composition ratio of the TbFeCo magnetic film.

In the above embodiment, TbFeC
In the above description, an example in which the magnetic film composed of O is formed in a layer structure is described. For example, TbFe, DyFeCo, GdFeC
Another magnetic film composed of o may be formed in a layered structure. In this case, by determining the area ratio of each region of the target according to the sputter rate and the composition ratio of the substance constituting the magnetic film, each layer can be formed into a layer structure having a predetermined thickness.

In the above-described embodiment, the case where a magnetic film is formed in a layer structure is described by taking a magneto-optical disk as an example. However, a phase change medium is formed in a layer structure in a phase change type optical disk. In this case, the present invention can be applied.
Further, the present invention is not limited to the above-described film formation of the magnetic film or the phase change medium, but can be applied to a case where a film made of a superconducting material is formed in a layer structure.

Further, the present invention can be applied to a technical field other than the film formation of an optical disk, for example, a film formation of a metal wiring of a semiconductor device.

[0058]

As described above, according to the film forming method according to any one of the first to third and seventh aspects, it is only necessary to use one target and mount this target on a single-wafer sputtering apparatus. Since a film having a layered structure can be formed, the cost for forming a film having a layered structure can be reduced, and the throughput can be improved.

Further, according to the optical disk manufacturing method of the present invention, a magnetic film having a layer structure can be formed simply by using one target and mounting the target in a single-wafer sputtering apparatus. Therefore, the cost for forming a magnetic film having a layer structure can be reduced, and the throughput can be improved. In addition, by forming the memory film of the optical disc into a layered structure, the memory film can have not only the characteristic that magnetization is vertically oriented as in the case of a uniform alloy but also the characteristic that the coercive force is high. .

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a single-wafer sputtering apparatus 10 and a target 11 according to a first embodiment.

FIG. 2 is a cross-sectional view illustrating a configuration of an optical disc 20.

FIG. 3 is a cross-sectional view illustrating a configuration of a memory film 23 formed on the optical disc 20.

FIG. 4 is a memory film 3 formed according to a second embodiment.
3 is a cross-sectional view illustrating the configuration of FIG.

FIG. 5 is an explanatory diagram showing a configuration of a target 31 used for forming the memory film 33 shown in FIG.

FIG. 6 is an explanatory diagram showing a configuration of a conventional simultaneous sputtering apparatus 60.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Single-wafer sputtering apparatus 11, 31, 61, 62 Target 20 Optical disk 21, 63 Substrate 22 Lower protective film 23, 33 Memory film 23a, 33a Basic layer 24 Upper protective film 60 Simultaneous sputtering device 64 Holder

Claims (7)

[Claims] When a basic layer in which a plurality of layers made of different substances are laminated is repeatedly formed on a substrate, a material constituting each layer of the basic layer is circumferentially divided for each substance. A film forming method, comprising: arranging one target so as to face the substrate, and performing sputtering while relatively rotating the substrate and the target. 2. The film forming method according to claim 1, wherein the target is divided into regions according to the number of substances constituting the basic layer, and each region of the target is formed of a substance constituting the basic layer. A film forming method comprising: 3. The film formation method according to claim 2, wherein an area ratio of each region of the target is a ratio of a thickness of each layer constituting the basic layer and a ratio of a sputtering rate of a substance of each layer. A film forming method characterized by being determined based on the above. 4. A method of manufacturing an optical disk using the film forming method according to claim 1, wherein one of the regions of the target is made of a rare earth metal. A method for manufacturing an optical disc, wherein the other area is made of a transition metal. 5. The method of manufacturing an optical disk according to claim 4, wherein the rare earth metal is terbium, and the transition metal is iron or an alloy of iron and cobalt. Method. 6. The method for manufacturing an optical disk according to claim 5, wherein each of the basic layers is formed on a substrate of the optical disk by 0.2 n.
A method for manufacturing an optical disk, comprising growing a substrate to a predetermined thickness greater than m and less than 3 nm. 7. The film forming method according to claim 1, wherein when a sputtering rate is R, a relative rotation number between the substrate and the target is R / 6 <Relative rotation number <R.
/0.4.