JPH0772341B2 - Plasma generator with pressure gradient type plasma gun - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma generator using a pressure gradient type plasma gun.

[0002]

2. Description of the Related Art Conventionally, a plasma generator using a pressure gradient type plasma gun can prevent the cathode from being damaged by ion backflow from the anode region, can stably heat the cathode from the time of ignition of the discharge, and can also discharge the electron flow. Because of the good gas efficiency of the carrier gas for producing, it is used in plasma generators such as ion plating, sputtering, and plasma CVD.

In the plasma generator, as disclosed in, for example, Japanese Patent Laid-Open No. 62-103362,
An annular plasma converging coil is provided near the tip of the pressure gradient type plasma gun, and the magnetic field of the coil is used to prevent the generated plasma from spreading outward.

By the way, since the strength of the magnetic field appearing around the steady current is given by the Biot-Savart law,
As shown in FIG. 6, the distribution of the magnetic field by the plasma focusing coil is maximum in the central portion, and the directions of the magnetic fields are opposite to each other inside and outside the plasma focusing coil.

Therefore, for example, Japanese Patent Laid-Open No. 63-473.
As disclosed in Japanese Patent Laid-Open No. 62-62, in an apparatus in which a plurality of pressure gradient plasma guns are arranged in a processing chamber and a substrate is formed by plasma generated from each pressure gradient plasma gun,
An annular plasma focusing coil is provided in each pressure gradient type plasma gun, and the plasma generated from each pressure gradient type plasma gun is regulated by each plasma focusing coil.

[0006]

However, in the plasma generator having the above-mentioned structure, even if the currents flowing through the respective plasma focusing coils are matched, it is not possible to generate completely equal magnetic fields, and the adjacent plasma focusing coils are not converged. There is a problem in that the magnetic field between the coils becomes discontinuous and the plasma distribution becomes non-uniform, that is, the ionization and excitation of the vapor deposition become non-uniform, and a uniform film quality cannot be formed on the substrate.

An object of the present invention is to provide a plasma generator using a pressure gradient type plasma gun capable of uniformizing plasma generated by a plurality of pressure gradient type plasma guns.

According to the present invention, in order to achieve the above-mentioned object, a plurality of pressure gradient type plasma guns having a plasma generator arranged in parallel on the same plane, and generating from the pressure gradient type plasma gun. And an elliptic plasma converging coil that surrounds the entire plasma.

[0008]

Therefore, according to the present invention, a substantially uniform magnetic field is generated in the plasma focusing coil over a wide range, and the generated plasma from each of the pressure gradient type plasma guns receives the uniform magnetic field.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a plasma generator using a pressure gradient type plasma gun according to the present invention will be described with reference to FIGS. FIG. 1 shows a case where the present invention is applied to an ion plating apparatus. Reference numeral 1 denotes a substrate made of a strip, 2 denotes a rectangular evaporation source hearth containing a deposit, and 3 denotes a plasma generator according to the present invention, which is attached to a processing chamber (not shown).

The plasma generator 3 comprises three pressure gradient type plasma guns 4 and one plasma focusing coil 5. The pressure gradient type plasma guns 4 are well known in the related art, and are arranged in parallel on the same plane at predetermined intervals. On the other hand, the plasma focusing coil 5 is, as shown in FIG.
The three pressure gradient type plasma guns 4 have an elliptical shape having parallel straight line portions 5a, 5a which face each other.
It is located between a and 5a. A magnetic field based on the Biot-Savart law is formed in the plasma focusing coil 5.

Next, the ion plating by the plasma generator 3 having the above structure will be described. When a processing chamber accommodating the substrate 1 is kept under vacuum and a voltage is applied to the discharge cathode of each of the pressure gradient type plasma guns 4, a cylindrical plasma is generated. This cylindrical plasma
The sheet plasma 6 having a desired width, thickness and density is expanded and contracted by an elongated permanent magnet (not shown). The sheet plasma 6 is restricted from spreading outward by the magnetic field of the plasma focusing coil 5 and converges on the evaporation source hearth 2 to evaporate the deposit in the evaporation source hearth 2. At this time, the magnetic field generated in the plasma focusing coil 5 has a magnetic field of the same strength in the space between the parallel straight line portions 5a, 5a of the plasma focusing coil 5, as is clear from the Biot-Savart law described above. To be done. On the other hand, each pressure gradient type plasma gun 4 has a plasma focusing coil 5
Since it is located between the parallel straight line portions 5a, 5a, the sheet plasma 6 from each of the pressure gradient type plasma guns 4 receives a magnetic field of the same strength and has a uniform distribution. The vapor of the vapor deposition material (metal, carbon, etc.) in the evaporation source hearth 2 is ionized or excited by the sheet plasma 6 to form the belt-shaped substrate 1. In this way, each plasma generated from each pressure gradient type plasma gun 4 becomes a sheet plasma having a uniform distribution by receiving a magnetic field of substantially the same strength by the plasma converging coil 5, so that the vapor of the vapor deposition material. The uniform ionization or excitation of the film makes it possible to form a uniform thin film on the substrate 1.

In the above-mentioned embodiment, the apparatus for ion-plating the substrate 1 made of a strip using the sheet plasma has been described. However, as shown in FIG. Plasma may be used. Further, as shown in FIG. 4, a sputtering apparatus for disposing a plate-shaped substrate 1 and a target 9 with a sheet plasma 6 sandwiched therebetween to perform a sputtering process, or as shown in FIG. 5, a source gas and a reaction gas are supplied. Then, it can be adopted in a plasma CVD apparatus for decomposing and exciting the reaction gas. 4 and 5, reference numeral 8 is an anode, and 6 is an anode-side plasma focusing coil having the same shape as the plasma focusing coil 5.

By the way, the plasma focusing coil 5 is
Although it may have an elliptical ring shape, as in the above-mentioned embodiment, the elliptic ring shape having the parallel straight line portions 5a can obtain a magnetic field of the same strength over a wide range and is excellent in the uniformity of plasma distribution. ing.

[0014]

As apparent from the above description, in the plasma generator using the pressure gradient type plasma gun according to the present invention, the magnetic field generated by one elliptic plasma focusing coil is used to generate pressure from each pressure gradient type plasma gun. Since the generated plasma is regulated at once, the plasma becomes a uniform state, and as a result of forming a continuous plasma,
Evaporation, ionization or excitation of the deposit can be performed uniformly, and the substrate can be formed into a uniform film.

Further, since only one plasma focusing coil is required, the power supply device can be simplified as compared with the conventional one, and the mounting pitch of each pressure gradient type plasma gun can be reduced to improve the uniformity of plasma. .

[Brief description of drawings]

FIG. 1 is an ion plating device to which a plasma generator is applied.

FIG. 2 is a front view of a plasma generator.

FIG. 3 is an ion plating apparatus provided with a plurality of evaporation source hearths to which a plasma generator is applied.

FIG. 4 is a sputtering apparatus to which a plasma generator is applied.

FIG. 5: Plasma CVD using a plasma generator
It is a device.

FIG. 6 is a graph showing the magnetic field strength of a conventional annular plasma focusing coil.

[Explanation of symbols]

4 ... Pressure gradient type plasma gun, 5 ... Plasma focusing coil, 5a ... Parallel straight line portion, 6 ... Plasma.

Claims (1)

[Claims] 1. A plurality of pressure gradient type plasma guns arranged side by side on the same plane, and an elliptic plasma focusing coil surrounding the entire plasma generated from the pressure gradient type plasma guns. Plasma generator with pressure gradient type plasma gun.