JPS63111173A - Sputtering device - Google Patents

Abstract

PURPOSE:To facilitate the migration of a charge on the surface of a target and to inhibit sudden temp. rise of a base plate by doping at least one of P, B, Sb, As and Ga into an Si-target and lowering the resistance of Si. CONSTITUTION:At least one of P, B, Sb, As and Ga is doped into the Si target 3 to lower the resistance thereof and the migration of a charge on the surface is facilitated. Both the Si target 3 and a base plate 4 opposed parallel thereto are provided. Then DC fed from a DC power source 7 is impressed in the mixed atmosphere of gaseous Ar and gaseous O2 or gaseous N2. A film of SiO2, SiO or Si3N4 is formed by a DC magnetron active sputtering method. Thereby an optical transparent film or a protective film in a photomagnetic recording medium is obtained.

Description

Detailed Description of the Invention (Industrial Application Field) This invention creates a sputtered film with high productivity by suppressing the rapid temperature rise of the substrate when creating a magneto-optical recording medium by the sputter link method. The present invention relates to a sputtering device capable of sputtering.

(Prior Art) FIGS. 4(a) and 4(b) show typical cross-sectional structures of magneto-optical recording media. The magneto-optical recording medium has a recording film 1
and an optically transparent film 2, and the optically transparent film 2 is also required to function as a protective film. This optically transparent film 2 needs to have chemical stability while maintaining appropriate optical properties, and be dense in terms of water permeation resistance. Traditionally, S has been used as a membrane material that has both of the above functions.
iO,5i02,AIN,Al5iN,Al5iO1S
iN, etc. are being considered, and each has its own characteristics.

Currently, sputtering equipment used to deposit 5102, SiO, or Si3N4 films uses RF magnetron sputtering using a SiO3 or Si3N4 target, or a high-purity Si target. The film is deposited by RF magnetrosiliactive sputtering in a mixed atmosphere.

In this case, the target 3 and the substrate 4 are positioned opposite each other, and the film is deposited either with the substrate stationary relative to the target as shown in FIG. 5, or as shown in FIG. This is done by rotating the substrate 4.

(Problems to be Solved by the Invention) However, according to the RF magnetron sputtering method, since the temperature of the substrate inside the film increases rapidly, the input power must be reduced in order to suppress this rate of increase. Accordingly, film application had to be carried out for a long time, resulting in poor productivity.

In addition, a necessary condition for an optically transparent film is that it has a good film thickness distribution, but when mass-produced using RF magnetron sputtering in mass production equipment, it is necessary to ensure uniformity of film thickness distribution using DC magnetron sputtering. difficult compared to.

This is because in RF discharge, for example, if the device structure is such that a film is applied while rotating the substrate, the plasma space changes, which has a large effect on the discharge characteristics.

Further, a discharge device using RF requires a matching device, and the power source is expensive.

The present invention has been made to solve the above-mentioned conventional problems, and its purpose is to
It is an object of the present invention to provide a sputtering apparatus that can deposit an i3N4 film by a DC magnetron reactive sputtering method, suppress a rise in temperature of a substrate, increase productivity, and ensure uniformity of film thickness distribution.

(Means for Solving the Problems) In order to achieve the above object, the present invention is configured as follows. That is, in a sputtering apparatus that uses Si as a target to create films such as TSi02, SiO, or Si3N as optically transparent films or protective films in magneto-optical recording media by RF magnetron sputtering, (7) P, B, Sb, As, It is characterized in that it is equipped with a Si target doped with at least one of Ga and a DC power source, and the above-mentioned desired film is created by a DC magnetron reactive sputtering method in a mixed atmosphere of Ar gas and 0□ gas or N2 gas. This is a sputtering device.

(Function) In the present invention having the above configuration, P, B, Sb, As
Doping a Si target with at least one of S Ga makes Si low resistance.

That is, the surface charge can be easily moved, and discharge can be performed even with DC.

(Example) FIG. 1 shows an embodiment of the invention.

That is, a substrate 4 held by a substrate holder 6 is held parallel to and opposed to an S1 target 3 fixed to a cathode 5 having a built-in magnet (not shown). Then, the film is formed in a mixed gas atmosphere of Ar gas and O2 gas or N2 scum.

The Si target 3 has P, B, Sb, A
Use a material doped with at least one of S and Ga to have a low resistance of 1Ω or less.

In order to obtain such a resistance value, it is necessary to perform doping of 0.5 ppm or more.

Then, when the Si target 3 is doped as described above to lower the specific resistance value of the target, charge movement on the target surface becomes easier, and discharge becomes possible even with DC. Therefore, a DC power supply 7 is used as the power supply.

However, as mentioned above, even though the resistance is low, the charge movement is poor compared to ordinary metals, so the charge tends to accumulate on the target surface, which causes abnormal discharge (arc discharge). It becomes easier. In order to prevent such abnormal discharge, it is effective to use an LC arc extinguishing circuit (surge current prevention circuit). Generally, when the duration of abnormal discharge exceeds milliseconds, the amount of dirt (splats) on the membrane increases rapidly, so by extinguishing the discharge in about 10 μs, it is possible to almost prevent the occurrence of sprats.

The arc extinguishing circuit is provided with an LC circuit formed by a coil (hereinafter referred to as "C") and a capacitor (hereinafter referred to as "C") between the DC power source 7 and the discharge chamber, and when an abnormal discharge occurs, the By free imaging as a transient phenomenon occurring in the LC circuit and the LC circuit, the voltage between the electrodes in the chamber is reduced to 0, thereby extinguishing the arc discharge at that point. If the arc is extinguished by -degree in this way, the discharge returns to normal glow discharge.

Fig. 1 shows the case where the LC arc extinguishing circuit is provided on the cathode 5 side, and Fig. 2 shows the case where the LC arc extinguishing circuit is provided on the D side.
The case where it is provided on the C power supply 7 side is shown. All of these are effective as surge current prevention circuits.

Figure 3 takes the case of creating a 1000A Si3N4 film as an example, and shows the case where RF discharge was performed using a Si target and the case where an Si target doped with As (specific resistance 0).
．． 100 m or less) or a P-doped Si target (specific resistance of 0.08 Ω or less) for DC discharge. The board at this time was φ120mm,
1. It is a 2mm thick PC (polycarbonate) disk. According to this, in the case of DC, the substrate temperature drops to half the value at 1000w0 compared to the case of RF.

Regarding film quality, the refractive index n is 2 for both RF and DC.
．． There was almost no difference in composition around 0. In addition, there was no particular difference between the BHF etch rate and the RFO film density evaluation.

When the LC arc-extinguishing circuit was not provided, 100 to 1000 sburats were observed on the film per 1 cTn2, but by providing the above circuit, almost no sburats were observed.

In the above example, the film was applied with the substrate stationary; however, the present invention is not limited to this, and during film application, the substrate was rotated as shown in Fig. 6. Also good.

(Effects of the Invention) According to the sputtering apparatus of the present invention, rapid temperature rise of the substrate can be suppressed, productivity can be increased, and abnormal discharge can be extinguished to prevent damage to the substrate and film formation. It is possible to prevent the occurrence of splats that adhere to the surface.

[Brief explanation of the drawing]

Figures 1 and 2 are schematic diagrams of a DC sputtering apparatus showing an embodiment of the present invention, Figure 3 is a graph showing the relationship between substrate temperature and input power, and Figure 4 (aXb) is a graph showing magneto-optical recording. 5 and 6, which are cross-sectional views showing typical structures of the medium, are schematic diagrams of a conventional RF sputtering apparatus. 2... Optical transparent film, 3... Si target, 4...
... Substrate, 5... Cathode, 6... Substrate holder,
7...DC power supply.

Claims (2)

[Claims] (1) SiO_2, SiO or Si_
A sputtering apparatus for forming each film of 3N_4 includes a Si target doped with at least one of P, B, Sb, As, and Ga, and a DC power source.
D in a mixed atmosphere of r gas and O_2 gas or N_2 gas
A sputtering apparatus characterized in that the above-mentioned required film is formed by a C magnetron reactive sputtering method. (2) The sputtering apparatus according to claim (1), characterized in that the apparatus is provided with a surge current prevention circuit.