JPH07169594A - Radical source device - Google Patents

Abstract

PURPOSE:To restrain reduction in a radical flux quantity by constituting an extraction electrode system of an insulating material such as Pyrex glass, quartz, alumina. CONSTITUTION:A electrode system 27 constituted of an insulating material such as Pyrex glass, quartz, alumina is provided. In the insulating material, when a recombination coefficient of a radical by collision and recombination is set in about 10<-5>, since the radical disappearing probability becomes very small as compared with conventional metal having a recombination coefficient of about 10<-2>, reduction in a radical flux quantity can be restrained. When an electrode system of metal of an ion source device is replaced with an electrode system of the insulating material, the ion source device can be used as a radical source.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radical source device for irradiating a substrate with radicals to form a good quality thin film.

[0002]

2. Description of the Related Art A conventional ion source device, for example, an MP (microwave plasma) cathode type ion source device has a structure as shown in FIG. In the figure, 1 is a main housing made of a non-magnetic metal material, 2 is a main plasma chamber formed by the main housing 1, 3 is openings formed on both sides of the main housing 1,
Reference numeral 4 denotes a metal ion beam extraction electrode system attached to one opening 3, and is composed of an acceleration electrode 5, a deceleration electrode 6, and a ground electrode 7 having different potentials. 8 is an insulator interposed between the flange of the main housing 1 and each of the electrodes 5, 6 and 7,
Reference numeral 9 is a permanent magnet provided outside the main housing 1 for generating a cusp magnetic field.

Reference numeral 10 is a sub-casing made of a non-magnetic metal material attached to the other opening 3, 11 is a sub-plasma chamber formed by the sub-casing 10, and 12 and 13 are magnets on both sides of the sub-casing 10. A cover plate made of a body or a non-magnetic metal material, 14 is a cover plate 13
, 15 is an electron emission hole in the center, 15 is an insulator between the sub-casing 10 and the main casing 1, and 16 is a gas inlet to the sub-plasma chamber 11.

Reference numeral 17 is a coaxial cable for introducing microwaves,
Reference numeral 18 is an antenna at the tip of the coaxial cable 17, and reference numeral 19 is an annular permanent magnet provided outside the sub-casing 10, which generates a magnetic field in the sub-plasma chamber 11 above an electron cyclotron resonance (ECR) condition. Reference numeral 20 is a sub-casing 10, a sub-plasma chamber 11, lid plates 12 and 13, an electron emission hole 14, an inlet 1.
6, an MP cathode composed of a coaxial cable 17, an antenna 18, and a magnet 19.

Reference numeral 21 denotes an arc power source for direct current discharge, the negative electrode of which is connected to the cover plate 12, and the positive electrode of which is connected to the main housing 1. Reference numeral 22 is an accelerating power source whose positive electrode is connected to the positive electrode of the arc power source 21, and whose negative electrode is grounded. Reference numeral 23 denotes a high resistance resistor provided between the positive electrode of the acceleration power source 22 and the acceleration electrode 5, 24 denotes a deceleration power source whose negative electrode is connected to the deceleration electrode 6, and the positive electrode is grounded.

When the ion source device is used as an ion source for irradiating the substrate, the sub-casing 10 is maintained at the cathode potential, gas is supplied from the inlet 16, and the sub-plasma chamber 11 is supplied.
A microwave is introduced into the antenna via the coaxial cable 17 and the antenna 18 to generate a microwave discharge, and the gas from the inlet 16 is ionized to generate a sub-plasma 25.

Next, the electrons ionized by the generation of the sub-plasma 25 are discharged into the main plasma chamber 2 through the electron emission holes 14, and the ionized gas such as a rare gas in the main plasma chamber 2 is ionized to generate the main plasma. 26 is generated, and ions are extracted from the main plasma 26 by the extraction action of the extraction electrode system 4.

When the ion source device is used as a radical source, the acceleration power source 22 and the deceleration power source 24 are stopped, that is, the volume is lowered to OV, and only radicals having no electric charge are selected from the main plasma 26 due to the pressure difference. It is released as a target.

[0009]

When the above-mentioned conventional ion source is used as a radical source, since the electrode system 4 is made of metal, the radicals are likely to disappear by collision with the electrode system 4 and recombination. Is extremely high, and there is a problem that the radical flux amount after passing through the electrode system 4 is greatly reduced as compared with the radical density in the main plasma 26. An object of the present invention is to provide a radical source device capable of suppressing the reduction of the amount of radical flux in view of the above points.

[0010]

In order to solve the above-mentioned problems, a radical source device of the present invention is a radical source device comprising a housing for generating plasma and an extraction electrode system,
The electrode system is composed of an insulating material such as Pyrex glass, quartz, and alumina.

[0011]

In the radical source device of the present invention configured as described above, since the extraction electrode system is made of an insulating material such as Pyrex glass, quartz, or alumina, the probability of radical extinction due to collision with the electrode system and recombination is reduced. It is very small, and the reduction in the amount of radical flux is suppressed. Further, the ion source device can be used as a radical source device by replacing the metal electrode system of the ion source device with an insulator electrode system.

[0012]

EXAMPLE One example will be described with reference to FIG.
2, the same reference numerals as those in FIG. 2 indicate the same or corresponding ones, and the difference from FIG. 2 is that instead of the metal ion beam extraction electrode system 4 of FIG. 2, an insulating material such as Pyrex glass, quartz, alumina or the like is used. The extraction electrode system 27 configured as described above is provided. The insulator has a radical recombination coefficient of about 10 ⁻⁵ due to collision and recombination, and is a metal having a conventional recombination coefficient of about 10 ^−2. In comparison, the radical extinction probability is very small, and the reduction in the amount of radical flux can be suppressed.

Next, the experimental results will be described. When an MP cathode type ion source having an outlet diameter of φ114 mm is used as the radical source, a quartz oscillator provided with an Ag film is arranged at a position facing the radical source, and the Ag film is irradiated with oxygen radicals to form an oxide film. The thickness was measured with a crystal oscillator type film thickness meter to measure the amount of radicals. As a result, the oxide film thickness was 920Å.

On the other hand, a similar experiment was conducted using a conventional ion source device as a radical source, and as a result, the oxide film thickness was 44.
The amount of radicals was 0Å, and the radical amount of the example was more than double that of the conventional example. Although the electrode system 27 is formed of three electrodes in the experimental example, the number of electrodes may be any number. The present invention can also be applied to a bucket type or Kauffman type ion source device.

[0015]

Since the present invention is constructed as described above, it has the following effects. In the radical source device of the present invention, since the extraction electrode system 27 is made of an insulating material such as Pyrex glass, quartz, or alumina, the probability of radical annihilation due to collision or recombination with the electrode system 27 is very small, and the radical flux amount Reduction can be suppressed. Furthermore, by replacing the metal electrode system of the ion source device with an insulator electrode system, the ion source device can be used as a radical source.

[Brief description of drawings]

FIG. 1 is a cutaway front view of an embodiment of the present invention.

FIG. 2 is a cut front view of a conventional example.

[Explanation of symbols]

 1 case 26 plasma 27 extraction electrode system

Claims (1)

[Claims] 1. A radical source device comprising a housing for generating plasma and an extraction electrode system, wherein the electrode system is made of an insulating material such as Pyrex glass, quartz, or alumina.