JPH0845126A - Film forming method - Google Patents

Abstract

PURPOSE:To decrease the time for film forming by etching a base dielectric layer simultaneously with forming a film. CONSTITUTION:A base dielectric layer (S layer) is formed on the surface of a substrate attached to a turntable T2 by impressing a high frequency electric field produced by 600W power between a SiN target ST4 and a chamber C1 for 20min to produce plasma discharge of the ST4 while the turntable T2 is rotated. While T2 is rotated, a high frequency electric field produced by 600W power is impressed for 15min to produce plasma discharge of the ST4 to from a S layer. At the same time, a high frequency electric field produced by 200W power is impressed between C1 and T2 for 15min to produce plasma discharge near T2 to etch the S layer. Then, while T2 is rotated, a high frequency electric field produced by 100W power is impressed between a Pt target 6 and C1 and between a Co target 5 and C1 to produce plasma discharge of the targets 6, 5 to alternately form Pt layers and Co layers to total 15 layers on the S layer. Thus, the required time to form films for a magneto-optical disk is decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a base dielectric layer on a substrate by a sputtering method and forming a recording magnetic layer on the base dielectric layer.

[0002]

2. Description of the Related Art A magneto-optical recording method for recording / reproducing by using a laser beam has a higher recording density than a magnetic recording method using a magnetic head, and a head and a recording medium at the time of recording / reproducing. Since and are not in contact with each other, they have an advantage of high reliability. Therefore, as a result of vigorous research, it has reached the level of practical use at present.

The wavelength of the currently used laser beam for magneto-optical recording is mainly 780 nm infrared light. Further, a rare earth-transition metal alloy represented by a TbFeCo film, which has a large magneto-optical effect (Kerr effect) near the infrared wavelength, is often used for the recording magnetic layer. In order to meet the demand for higher density in the future, the shorter the wavelength of the laser light source, the more the light flux can be narrowed down. Therefore, it becomes possible to write smaller pits. Research on high-power blue laser light source of AK has been actively conducted. Further, in the above rare earth-transition metal alloy-based material, the magneto-optical effect is deteriorated when the laser light has a short wavelength. Therefore, a Pt / Co laminated film having a large magneto-optical effect in the blue to green short wavelength region is formed. , Is being studied as a recording magnetic layer for future high-density magneto-optical recording.

In either case of the rare earth-based recording magnetic layer or the Pt / Co laminated film recording magnetic layer, a base dielectric layer is provided between the substrate and the recording magnetic layer to improve the carrier level. The magneto-optical effect at a certain specific wavelength is increased by utilizing the interference effect of light. Conventionally, after the underlying dielectric layer is formed and before the recording magnetic layer is formed, the underlying dielectric layer surface is reverse-sputtered to smooth the surface.
This is called an etching process. In particular, in the Pt / Co laminated film, there is a large change in the perpendicular magnetic anisotropy and the magnetization characteristic between when the etching process is performed and when it is not performed. For example, in a magneto-optical recording medium, it is required that the perpendicular direction to the film surface is a perpendicular magnetization film whose easy axis is the axis of magnetization. It has been found that even if there is no such film, a completely perpendicular magnetization film having a squareness ratio of 100% can be obtained by performing the etching process.

A conventional film forming method by sputtering will be described with reference to FIG. In FIG. 2, 1 is a chamber of an RF magnetron sputtering apparatus, 2 is a turntable for mounting a substrate (not shown) on the lower surface side, 3 is a rotary shaft for rotating the turntable 2, and 4 is Si for an underlying dielectric layer.
N target, 5 Co target, 6 Pt target, and 7 discharge plasma. First, turntable 2
While rotating the SiN, a high frequency electric field is applied between the SiN target 4 and the chamber 1 as shown in FIG.
The target 4 is plasma-discharged to form a SiN layer (base dielectric layer) on the substrate surface on the lower surface side of the turntable 2, and then the chamber 1 and the turntable (= substrate) as shown in FIG. 2B. A high-frequency electric field is applied between the SiN and
The layer is subjected to an etching treatment, and then a high frequency electric field is applied between the Pt target 6 and the chamber 1 and the Co target 5 and the chamber 1 as shown in FIG. 2C to plasma discharge the Pt target 6 and the Co target 5. Then, Pt layers and Co layers are alternately laminated on the SiN layer. In this way, the underlying dielectric layer and the recording magnetic layer are formed.

[0006]

In the above-mentioned conventional film forming method, it takes time for the etching process between the step of forming the underlying dielectric layer and the step of forming the recording magnetic layer. However, the film formation time is prolonged, which is an obstacle to cost reduction. It is an object of the present invention to shorten the film forming time and reduce the manufacturing cost in the film forming method of a magnetic recording medium by the sputtering method.

[0007]

The present invention relates to a film forming method for forming a base dielectric layer on a surface of a substrate by a sputtering method and then forming a recording magnetic layer on the base dielectric layer. The film forming method is characterized in that an etching process is performed at the time of forming the underlying dielectric layer. Further, the present invention, the substrate and the target are arranged in the chamber so as to face each other, by a sputtering method of applying a high frequency electric field between the chamber and the target, after forming a base dielectric layer on the substrate surface, In a film forming method for forming a recording magnetic layer on the underlying dielectric layer, the underlying layer is formed by applying a high frequency electric field between the turntable and the chamber when forming the underlying dielectric layer. The film forming method is characterized in that the dielectric layer is subjected to etching treatment. The etching process may be started after a lapse of a predetermined time from the start of forming the underlying dielectric layer. Further, the high frequency electric field applied between the substrate and the chamber may be turned on / off at a predetermined cycle.

[0008]

Function: An underlying dielectric layer is formed on a substrate by a sputtering method in which a high frequency electric field is applied between a chamber and a dielectric target, and at the same time, an etching is performed in which a high frequency electric field is applied between the turntable (= substrate) and the chamber. Treatment is applied to the underlying dielectric layer being deposited. After that, a recording magnetic layer is formed on the underlying dielectric layer by a sputtering method in which a high frequency electric field is applied between the chamber and the recording magnetic target.

[0009]

EXAMPLE An example of the present invention will be described below. FIG. 1 is an explanatory view showing a film forming method of the embodiment, FIG. 3 is a schematic view showing a sectional structure of a magneto-optical disk formed by the embodiment method, and FIG.
5 is a characteristic diagram showing a Kerr loop of a magneto-optical disk manufactured by using the film forming method of the embodiment, and FIG. 5 is a characteristic diagram showing a Kerr loop of a magneto-optical disk manufactured by using a conventional film forming method.

In FIG. 1, 1 is a chamber of an RF bipolar magnetron sputtering apparatus, 2 is a turntable for mounting a substrate on the lower surface side, 3 is a rotary shaft for rotating the turntable 2, and 4 is SiN for an underlying dielectric layer. Target 5 is a Co target, 6 is a Pt target, and 7 is discharge plasma. Here, SiN target 4 and Co
The target 5 and the Pt target 6 have a diameter of 5 inches. The ultimate vacuum of the chamber 1 is 1 × 10 -6 To
rr or less, the Ar gas flow rate during film formation is 56 SCCM, Ar
The pressure is 7.5 mTorr. In addition, in FIG.
8 is a substrate, 17 is a SiN layer (underlying dielectric layer) formed on the substrate 18, 15 is a Pt layer, 16 is a Co layer, S
The film thickness of the iN layer is 800Å, and the film thicknesses of the Pt layer 15 and the Co layer 16 are 7Å and 4Å, respectively.

* Manufacture of Example Samples A film forming process and an etching process were performed as follows. First, while rotating the turntable 2 having the substrate attached thereto, a high frequency electric field was applied between the SiN target 4 and the chamber 1 at an applied power of 600 W for 20 minutes as shown in FIG. Then, a SiN layer (underlying dielectric layer) was formed on the substrate surface on the lower surface side of the turntable 2.

Next, the turntable 2 with the substrate attached
As shown in FIG. 1B, a high frequency electric field is applied between the SiN target 4 and the chamber 1 at a power of 600 W for 15 minutes while rotating the SiN target 4 to plasma-discharge the SiN target 4 and the substrate on the lower surface of the turntable 2. SiN on the surface
While depositing a layer (underlying dielectric layer), an electric power of 20 is applied between the chamber 1 and the turntable (= substrate) 2 at the same time.
Apply high frequency electric field for 15 minutes at 0 W and turntable 2
Plasma discharge was performed in the vicinity of to etch the SiN layer.

Next, the turntable 2 with the substrate attached
While rotating, the Pt target 6 and the chamber 1 and the Co target 5 and the chamber 1 as shown in FIG.
A high frequency electric field is applied with an applied power of 100 W between them to plasma discharge the Pt target 6 and the Co target 5 to alternately form 15 layers of Pt layers and Co layers on the SiN layer to form a recording magnetic layer. did. In this way, a magneto-optical disk having the structure shown in FIG. 3 was obtained.

* Comparison of Characteristics between Example Sample and Conventional Example Sample The characteristics of the example sample manufactured by the above method and the conventional example sample manufactured by the conventional method were compared as follows. Here, the conventional sample is a light produced by performing only film formation of the SiN layer (underlying dielectric layer) at an applied power of 600 W for 35 minutes and then performing only an etching process at an applied power of 200 W for 15 minutes. This is a magnetic disk, and the recording magnetic layer is formed by the same method as the above-described example samples.

FIG. 4 shows the Kerr loop of the example sample measured with a laser beam having a wavelength of 780 nm, and FIG. 5 shows the Kerr loop of the conventional example sample measured under the same conditions as the example sample. The characteristics such as the size of the Kerr loop, the coercive force of the loop, and the squareness have a great influence on the recording / reproducing characteristics of the magneto-optical disk, but as is clear from the comparison between FIG. 4 and FIG. The rotation angle is 0.84 deg and the coercive force is about 1.2 kOe, showing almost the same characteristics. It also has good squareness.

Next, the write laser power vs. CNR (carrier to noise ratio) characteristics in the optical modulation recording method were measured for each of the magneto-optical disks of the example sample and the conventional example sample. A rotation frequency of the magneto-optical disk was set to 1800 rpm, and a frequency signal of 1 MHz was recorded at a disk radius of 40 mm using a laser beam having a wavelength of 830 nm and a duty ratio of 50%. The recording pit length is about 3.7 μm.
The externally applied magnetic field at the time of recording was 200 Oe, and the laser power was changed from 2 mW to 10 mW in steps of 2 mW. When the signal thus recorded was read out with a laser power of 1 mW, the CNR exhibited substantially the same characteristics in each of the magneto-optical disks of the example sample and the conventional example sample. For example, when the writing laser power was 6 mW, the magneto-optical disk of the example sample had a gain of 50.6 dB, and the magneto-optical disk of the conventional sample had a gain of 50.4 dB. From the above results, it can be seen that the magneto-optical disk of the example sample and the magneto-optical disk of the conventional sample have the same characteristics.

In the above embodiment, the etching process is performed in parallel during the final 15 minutes of the film formation process of the base dielectric layer for 35 minutes. Not limited to. Further, the etching process and / or the film forming process of the underlying dielectric layer performed in parallel may be periodically turned on / off. Further, for example, a plurality of substrates are attached to the turntable, and a substrate on which the underlying dielectric layer is being formed and a substrate on which the underlying dielectric layer is not being formed are
When they exist periodically (every time the turntable rotates), the etching treatment may be repeated cyclically only on the substrate that is not being film-formed. Further, the present invention can be applied not only to a magneto-optical disk but also to a film forming method for a magnetic recording medium by a sputtering method.

[0018]

According to the present invention, since the etching process of the underlying dielectric layer is performed concurrently with the film formation of the underlying dielectric layer, the time required for the film formation can be shortened, and therefore the manufacturing cost of the recording medium can be reduced. It can be reduced. Further, the characteristics of the recording medium thus formed are comparable to those of the recording medium formed by the conventional method.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a film forming method of an example.

FIG. 2 is an explanatory view showing a conventional film forming method.

FIG. 3 is a schematic diagram showing a cross-sectional structure of a magneto-optical disk formed by an example method.

FIG. 4 is a characteristic diagram showing a Kerr loop of a magneto-optical disk manufactured by using an example method.

FIG. 5 is a characteristic diagram showing a Kerr loop of a magneto-optical disk manufactured by a conventional method.

[Explanation of symbols]

 1 chamber 2 turntable 3 rotating shaft 4 SiN target 5 Co target 6 Pt target 7 discharge plasma

Claims (4)

[Claims] 1. A method for forming a base magnetic layer on a surface of a substrate by a sputtering method, and then forming a recording magnetic layer on the base dielectric layer, the method comprising forming the base dielectric layer. A film forming method, characterized in that the underlying dielectric layer is subjected to etching treatment during film formation. 2. A substrate and a target are arranged to face each other in a chamber, and a base dielectric layer is formed on the surface of the substrate by a sputtering method in which a high frequency electric field is applied between the chamber and the target, In a film forming method for forming a recording magnetic layer on a base dielectric layer, an etching process for applying a high frequency electric field between the substrate and the chamber is performed at the time of forming the base dielectric layer. Characteristic film forming method. 3. The film forming method according to claim 2, wherein the etching process is started after a lapse of a predetermined time after the film formation of the underlying dielectric layer is started. 4. The film forming method according to claim 2, wherein the high frequency electric field applied between the substrate and the chamber is turned on / off at a predetermined cycle.