JP3199273B2 - Microwave discharge reactor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a microwave discharge reactor, and more particularly to a microwave discharge reactor suitable for a dry etching apparatus, a plasma CVD apparatus, a sputtering apparatus, a surface reforming apparatus, and the like.

[0002]

2. Description of the Related Art Many thin film forming and processing apparatuses utilizing microwaves have been known. Among them, there is an apparatus that utilizes the interaction between an electric field generated by a microwave and a magnetic field generated by a magnet. As one example, there is a type of ordinary microwave discharge device that uses electron cyclotron resonance (ECR) that can generate high-density plasma at low pressure. This device is also known as a microwave discharge reaction device that includes a magnetic field generating means using a solenoid coil or a permanent magnet, and forms and processes an extremely fine thin film.

[0003] As a microwave discharge reaction device using a magnetic field, a number of configuration examples using a solenoid coil have been proposed so far. However, microwave discharge reactors using only permanent magnets have been actively proposed.

In the configuration using a permanent magnet, when a large number of small magnets are used in combination, a large, heavy and expensive solenoid coil is used.
The entire device can be made compact and inexpensive. Further, since the influence area of the magnetic field can be limited to the vicinity of the magnet, the magnetic field near the substrate can be made substantially zero. Therefore, there is an advantage that it is not necessary to control the direction of the magnetic field lines near the substrate. As a microwave supply device,
Conventionally, waveguides have been exclusively used. At present, a configuration has been proposed in which microwaves are supplied to an antenna such as a slot antenna or a rigidano coil using a coaxial tube.
The configuration examples of these microwave supply apparatuses are made for the purpose of generating a large-diameter uniform and high-density plasma for processing a large-area substrate.

[0005]

Many of the conventional microwave discharge reactors proposed for forming a thin film or processing a substrate can maintain a discharge at a lower pressure and can cope with a substrate having a larger area. Points are placed at two points.

[0006] In recent years, many microwave discharge reactors using a solenoid coil, which can process a large-sized substrate and discharge at a low pressure, have been studied. However, in such an apparatus, it is usually necessary to make the inner diameter of the solenoid coil larger than the outer diameter of the substrate, and therefore, there is a problem that an extremely large, heavy, and expensive coil is required.

Further, when a solenoid coil is used, it is not easy to make the intensity and direction of the magnetic field near the substrate uniform.
Therefore, many devices for controlling the plasma state near the surface of the substrate are required. Among them, there has been proposed an apparatus for processing a large-area substrate by, for example, arranging a plurality of solenoid coils and combining them, or expanding the stable region of plasma by using a permanent magnet together with the solenoid. However, at the current technical level, an apparatus capable of processing a large amount of substrates at high speed and at low cost has not been developed.

In recent years, microwave discharge reactors using only a magnetic field generated by a permanent magnet have been actively proposed.
In the formation of a magnetic field using a permanent magnet, a strong magnetic field can be formed only in the vicinity of the magnet on another side, and a minimal magnetic field can be formed by devising the arrangement of the magnet.
Thus, plasma confinement and plasma generation 2
Various configurations are being considered for one purpose.

However, when plasma is generated only by permanent magnets, there is a problem that it is not easy to increase the plasma density on the front surface of the substrate only by arranging the magnets around the substrate. In order to solve this problem, a configuration in which a plurality of permanent magnets are disposed on the front surface of the substrate has been studied. In this configuration, the microwave is provided by a waveguide or antenna. In the supply by the waveguide, a circular waveguide having a size approximately equal to that of the substrate is used. Therefore, as the substrate area increases, there is a problem that a uniform plasma cannot be generated. On the other hand, when microwaves are supplied to the antenna using a coaxial tube, there is a problem that it is difficult to efficiently supply large power.

An object of the present invention is to use a permanent magnet to generate a large-diameter and uniform high-density plasma useful for processing a substrate having a large area. An object of the present invention is to provide a microwave discharge reactor that can be processed and can be manufactured at low cost.

[0011]

The microwave discharge reaction apparatus according to the present invention generates plasma in a depressurized internal space of a vacuum vessel based on microwaves introduced by a microwave introduction mechanism, and uses the plasma to generate a substrate. A microwave discharge reaction device that processes microwaves, which converts microwaves radiated from the microwave radiator of the microwave introduction mechanism into the vacuum vessel into plane-wave microwaves and widely supplies the microwaves to the front space of the substrate. The concave portion is provided with a parabolic wall provided facing the substrate , and the microwave radiator is disposed at the focal position toward the inner surface of the parabolic wall, and the parabolic wall and the microwave radiator are a substrate is placed in the microwave radiation chamber formed in a state that is isolated from the arrangement by the discharge chamber, between the discharge chamber and the microwave radiation chamber, separating both the chambers to and transmit microwave Las material is arranged parallel to the substrate, a glass material, a plurality of permanent magnets forming a magnetic field in the discharge chamber,
The magnetic poles are arranged so that their polarities are alternately reversed, and are configured to generate plasma in a predetermined space region of the discharge chamber by interaction between the microwave and the magnetic field.

[0012]

In the microwave discharge reaction device according to the present invention, a microwave reflecting member having a concave surface facing the substrate is provided opposite to the substrate, and the microwave reflecting member is a microwave radiator of a microwave introducing mechanism. Is converted into a plane-wave-like microwave by its reflection and supplied to the substrate. The microwave supplied to the substrate generates plasma capable of processing a large-area substrate with high uniformity in a wide area in front of the substrate. A member forming a parabolic wall is used as the microwave reflecting member. Further, the microwave radiator is arranged at the focal position with respect to the paraboloid wall. Further, in the front space of the substrate, a glass material for separating the discharge chamber and the microwave radiation chamber is arranged in parallel with the substrate, and a plurality of permanent magnets are provided on the glass material to generate a magnetic field that interacts with the electric field generated by the microwave. By placing permanent magnets in a limited predetermined area near the permanent magnets, high-density and highly uniform plasma can be formed in the front space of the substrate, and large-area substrates can be uniformed at high speed. Can handle well.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view of a main part of a microwave discharge reaction device according to the present invention, FIG. 2 is a diagram showing how microwaves are transmitted in a radiation chamber, and FIG. 3 is a diagram showing a plasma generation state near a permanent magnet. FIG. In FIG. 1, illustration of a microwave generation device and a supply device, a gas introduction system, an exhaust system, and the like are omitted for convenience of description.

First, FIG. 1 will be described. A is the discharge chamber,
B is a microwave radiation chamber. The discharge chamber A is formed by the discharge chamber housing 1, and the microwave radiation chamber B is formed by the radiation chamber housing 2. The discharge substance A and the microwave radiation substance B are installed adjacent to each other. Between them, a glass material 3 and a plurality of permanent magnets 4 arranged inside the glass material are provided. The permanent magnet 4 is fixed with a material that is very transparent to microwaves. The glass material 3 is plate-shaped and has a peripheral portion. The glass material 3 is fixed with its peripheral portion sandwiched between the discharge chamber housing 1 and the radiation chamber housing 2 described above. In this fixing, an O-ring 5 is used. Thus, the discharge chamber A and the microwave radiation chamber B are separated by the glass material 3. Further, a metal gasket 6 is provided at a contact portion of each of the housings 1 and 2 to maintain airtightness inside.

FIG. 3 is an enlarged view of a part of the structural part composed of the glass material 3 and the permanent magnet 4. As the glass material 3, for example, two quartz glass plates (3a, 3b) are prepared, and these are made to face each other. The permanent magnet 4 is fixed between the two quartz glass plates 3a and 3b via a spacer (not shown).

The required number of permanent magnets 4 are arranged. As the material of the permanent magnet 4, for example, a material having a small loss with respect to microwaves such as ferrite is used. The plurality of permanent magnets 4 are provided in the discharge chamber A in consideration of the positional relationship of the magnetic poles so that a required magnetic flux distribution 7 is formed. The ability of the permanent magnet to create a magnetic field
In the space near the front surface of the magnetic pole portion of the permanent magnet 4 on the side,
It is desirable to have a magnetic flux density or higher that satisfies the ECR condition (875 gauss for 2.45 GHz microwave).

A substrate support mechanism 8 and a substrate 9 supported by the substrate support mechanism 8 are arranged inside the discharge chamber housing 1. The substrate 9 is arranged in an upright state. Therefore, the substrate 9 faces the surface formed by one magnetic pole of the plurality of permanent magnets 4 installed in the glass material 3. The discharge chamber housing 1 has a gas introduction pipe 10 and an exhaust port 1.
1 is provided.

The left end of the radiation chamber housing 2 in FIG. 1 is open, and a member forming a parabolic wall 12 is fixed to the left end. A microwave introduction pipe 13 is connected to a center position of the paraboloid wall 12. Microwave introduction tube 13
Is extended and penetrated into the microwave radiation chamber B, and a microwave primary radiator 14 is provided at the right end in the figure. A microwave power supply, an isolator, a power monitor, and a microwave power supply attached to the left end of the microwave introduction pipe 13 in the drawing.
Illustration of a microwave supply device such as a tuner is omitted.

The operation of the microwave discharge reactor having the above configuration will be described. First, an exhaust system (not shown) is operated to exhaust air from the exhaust port 11, and the inside of the discharge chamber A is brought into a required vacuum state. Further, after that, a gas introduction system (not shown) is operated to introduce a predetermined gas into the discharge chamber A from the gas introduction pipe 10. Adjust the gas introduction flow rate and pumping speed appropriately,
A predetermined gas pressure state is created in the discharge chamber A. The pressure at this time is preferably about 10 ⁻³ Torr to about 10 ⁻⁶ Torr. When the discharge chamber A reaches such a condition, a microwave discharge is generated in the discharge chamber A.

In order to generate a microwave discharge, the microwave generated by the above-described microwave supply mechanism is applied to the radiation chamber B.
To supply. The microwave is introduced into the radiation chamber B by the microwave introduction tube 13. The microwave introduced by the microwave introduction tube 13 is radiated into the radiation chamber B by the microwave primary radiator 14. At this time, the microwave is radiated toward the inner surface (concave surface) of the parabolic wall 12, reflected by the inner surface of the parabolic wall 12, and supplied toward the discharge chamber A. The reflected microwave is transmitted through the transparent glass material 3 and supplied into the discharge chamber A. In the discharge chamber A, plasma is generated by interaction between electrons generated by microwave discharge and a magnetic field generated by the permanent magnet 4.

As shown in FIG. 2, the installation position of the microwave primary radiator 14 is the position of the focal point of the parabolic wall 12. Accordingly, the microwave 15 radiated from the microwave primary radiator 14 is reflected by the inner surface of the paraboloid wall 12, and is converted into a microwave in a plane wave state having a phase aligned in the radiation direction.

The microwave supplied as a plane wave in the direction of the discharge chamber A passes through the glass material 3 as shown in FIG. In the discharge chamber A, high-density plasma is generated in a restricted region 16 near the permanent magnet where the direction of the electric field of the microwave 15 and the direction of the magnetic field by the permanent magnet 4 are orthogonal. The plasma generated in the space region near the permanent magnet 4 is diffused freely inside the discharge chamber A at a location distant from the permanent magnet 4 because it is not substantially affected by the magnetic field. As a result, a predetermined limited space area in front space of the substrate with a large diameter, it is possible to form a good high-density plasma very uniformity in a wide area region corresponding to the substrate area of this. Thus, a large-area substrate can be processed at high speed and with good uniformity.

In the above embodiment, a wall having any shape can be provided in place of the parabolic wall 12 as long as it has a function of supplying a microwave having a plane wave shape to the discharge chamber A. The arrangement of the permanent magnets 4 is alternately arranged such that the magnetic pole arrangement of the permanent magnets on a plane opposed to the substrate 9 is different between adjacent ones so as to form a required magnetic field in the space in front of the substrate 9 in the discharge chamber A. Are arranged.

As another embodiment, even when a permanent magnet is not used, microwaves are injected into the entire discharge chamber based on the microwaves radiated from the microwave radiating chamber, and the same as in the above-described embodiment. A substrate having an area can be processed with good uniformity. Further, instead of using a permanent magnet, other magnetic generating means for generating a similar magnetic field can be used.

As still another embodiment, the microwave radiating chamber and the discharge chamber can be configured as one vacuum vessel without being provided separately.

In the illustrated example of the above embodiment, an example in which the substrate is set upright has been described.
The same configuration as the above embodiment can be applied.

[0027]

As is apparent from the above description, according to the present invention, in a microwave discharge reaction device, a microwave is converted into a plane wave by a reflection action and supplied to the front space of the substrate.
An interaction is generated between the electric field generated by the microwave and a magnetic field in a limited area formed by a plurality of permanent magnets and the like arranged in the front space of the substrate. A high-density plasma can be generated with high uniformity, so that a large amount of large-area substrates can be processed at high speed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a microwave discharge reaction device according to the present invention.

FIG. 2 is a diagram showing how a microwave is transmitted in a microwave radiation chamber.

FIG. 3 is a diagram showing a plasma generation state near a permanent magnet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge chamber housing 2 Radiation chamber housing 3 Glass material 4 Permanent magnet 7 Magnetic flux distribution 9 Substrate 12 Parabolic wall 13 Microwave introduction tube 14 Microwave primary radiator 15 Microwave 16 High density plasma generation area

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 16/00-16/56 H01L 21/205 H01L 21/3065 H01L 21/31

Claims (1)

(57) [Claims] 1. A vacuum vessel in which plasma is generated inside a vacuum-pressurized state, a gas introduction mechanism for introducing a predetermined processing gas into the vacuum vessel, and a microwave introduction for introducing microwaves into the vacuum vessel. And a substrate support mechanism for supporting the substrate. The microwave radiator of the microwave introduction mechanism emits light.
Is converted into a plane wave microwave,
The concave part that supplies widely to the front space of the substrate is
A parabolic wall provided opposite to the plate;
The wave radiator has its focal position facing the inner surface of the parabolic wall.
The parabolic wall and the microwave radiator are disposed on the substrate.
Placed in a microwave radiation chamber isolated from the placed discharge chamber
And generating the plasma based on the microwave and treating the substrate with the plasma, wherein the two chambers are isolated between the discharge chamber and the microwave emission chamber.
The glass material that transmits the microwave
Placed in parallel with the glass material, a magnetic field in the discharge chamber
A plurality of permanent magnets that form
The microwave and the magnetic field are provided in opposite directions.
Interacts with a predetermined space region of the discharge chamber.
A microwave discharge reactor characterized by generating plasma .