JPS63214345A - Plasma processing apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention mainly applies to CVD (Che+5ical vapor
The present invention relates to a plasma processing apparatus used as a deposition apparatus, etc.

[Prior art]

In general, radio waves (RF waves) or microwaves are used as an excitation means for generating low-temperature plasma, but microwaves have lower temperature and higher density than radio waves. It has advantages such as being able to obtain plasma, being free from electrode contamination, and being easy to use and operate the device.

Conventionally, the electron cyclotron resonance (ECR) method is widely known as a plasma processing device that uses microwaves (Japanese Patent Application Laid-open No. 141729/1983), but this method uses a magnetic field, so it has good directivity, and Although it has the advantage of good film quality because plasma is generated under high vacuum,
The problem was that the processing area was small. A method that can obtain a larger processing area than this electron cyclotron resonance method is a method in which microwaves are introduced into the plasma generation chamber using an antenna (Japanese Patent Application Laid-Open No. 56-41382, 57-9868).
), but this method is difficult to match with the antenna,
There was a problem that the plasma distribution tended to become non-uniform.

For this reason, in recent years, a method using a ladder-like periodic structure (The Large Volume Micro
avePlasma Generator J, Mi
Crowave Power 7 (4) 1972)
Alternatively, methods using dielectric covered lines have been attempted, and the present inventors have already proposed a method using dielectric covered lines (Japanese Patent Application No. 14303/1986).
No. 6, No. 60-240070).

[Problem that the invention seeks to solve]

By the way, although the plasma processing apparatus of the above-mentioned type can set a wide processing area, the directivity of the plasma is not sufficient and there is a problem with the uniformity of processing.Also, since the sample is placed inside the plasma generation chamber, there are problems during film formation. There were problems such as large ion bombardment, poor film quality, and furthermore, when a reactive gas was supplied into the plasma generation chamber, a large amount of film was deposited on the wall surface of the plasma generation chamber, making plasma generation unstable.

The present invention has been developed in view of the above circumstances, and its purpose is to generate plasma over a large area using microwaves, increase directivity, and enable uniform treatment of the sample surface. Another object of the present invention is to provide a plasma processing apparatus that eliminates film adhesion to the wall surface of a plasma generation chamber, prevents instability of plasma generation, and enables effective use of reaction gas.

[Means for solving problems]

The apparatus of the present invention includes a plasma generation chamber at least partially formed of a heat-resistant wall through which microwaves can pass, a sample processing chamber in which a sample is placed, and a plasma generation chamber along the sample processing chamber. a means for introducing microwaves so that a standing microwave wave is formed; and a chamber formed by dividing the plasma generation chamber and having a low electric field strength including a node of the standing wave and an antinode of the standing wave. A chamber with a high electric field strength and a material that blocks microwaves are arranged to separate the plasma generation chamber and the sample processing chamber, and each chamber with a low electric field strength and a chamber with a high electric field strength are arranged to separate the plasma generation chamber and the sample processing chamber. It is equipped with a partition wall with a communication port connecting it to the sample processing room.

[Effect]

According to the present invention, this makes it possible to uniformly direct the plasma toward the sample, eliminate film adhesion to the inside of the plasma generation chamber, stabilize plasma generation, and effectively utilize reactant gas and the like.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on drawings showing embodiments thereof. FIG. 1 shows a plasma process apparatus (
1 is a schematic cross-sectional view of the device (hereinafter referred to as the device of the present invention).
2 shows a reactor, and 2 shows a dielectric covered line.

A gas introduction system 3 and an exhaust system 4 are connected to the reactor 1, and a microwave oscillator 6 is connected to the dielectric covered line 2 via a waveguide 5; The reactor 1 is arranged substantially horizontally, while the reactor 1 is located below the dielectric covered line 2 and is arranged slightly inclined so that its upper surface faces the waveguide 5 side.

Figure 2 (a) is an enlarged sectional view of reactor 1, and Figure 2 (b) is a waveform diagram of standing microwave waves formed in the plasma generation chamber inside the reactor. It has a rectangular parallelepiped shape and is entirely made of metal except for the upper wall, and the surrounding wall in particular has a double structure and is equipped with a circulation chamber 11 for cooling water inside.
The upper wall of the reactor 1 is hermetically sealed with a heat-resistant plate 12 with low dielectric loss that allows microwave transmission, such as quartz glass or Pyrex glass, and is opposed to this heat-resistant plate 12 with low dielectric loss. The dielectric covered lines 2 described above are arranged facing each other.

The inside of the reactor 1 is divided into upper and lower parts by a partition wall 13 arranged parallel to the heat-resistant plate 12 near the upper end.
The upper part of 3 is a plasma generation chamber 14, and the lower part of the partition wall 13 is a sample processing chamber 15. Microwaves are introduced into the plasma generation chamber 14 by passing through the heat-resistant plate 12 at the upper part. A standing wave as shown in FIG. 2(b) is likely to be formed.

Inside the plasma generation chamber 14, a partition wall 14a is passed between the partition wall 13 and the heat-resistant plate 12 to create a chamber A+ with a low electric field strength that includes nodes of standing waves and a chamber with a high electric field strength that includes antinodes of standing waves. The chamber A0, which has a large electric field strength including the antinode of the standing wave, has a supply pipe 3a for plasma source gas constituting the gas supply system 3 at one end, and a chamber A0 which has a node of the standing wave. The chamber A containing a small electric field strength has a reactive gas supply pipe 3b, which also constitutes the gas supply system 3, at one end thereof.
are connected to each other. On the other hand, the sample processing chamber 15 is connected to an exhaust pipe 4a constituting the exhaust system 4, and inside the sample 16 is arranged on a support (not shown) in front of the partition wall 13 at a required distance β and substantially parallel to the partition wall 13. It is set up.

The partition wall 13 is made of a material capable of shielding microwaves, mainly metal such as stainless steel.
Slit-shaped communication ports 13a and 13b communicating with the sample processing chamber 15 are opened at positions facing O and A+, respectively, and the gas supplied to the chamber A0 is plasma decomposed, and the generated plasma, radicals, etc. are communicated. The reactive gas supplied to the chamber Al through the port 13a is slightly excited and then passes through the communication port 13b to the sample processing chamber 15 due to the pressure difference formed between the chambers A, A and the sample processing chamber 15. It is designed so that it can be guided into the processing chamber 15 and directed toward the surface of the sample 16.

Although the shape of the communication ports 13a and 13b has been described as a slit shape, the shape is not limited to this in any way (for example, it is of course possible to have a large number of circular or square pores).

The dimension l between the sample 16 and the partition wall 13 is not particularly limited to this, but for example, if the mean free path of the gas is λ and it is set so that β≦λ, the plasma will move between the sample 16 and the sample 16 without collision between particles. As a result, a plasma beam with excellent upward movement can be obtained.

In addition,! If l is made small, the beam spread will be small and the amount of ions in the beam will be large. Conversely, if l is made large, the beam spread will be large and most of the beam will be a radical beam, so the size of the sample 16 and the properties of the beam will be The dimension i may be determined by taking these factors into consideration.

In the above embodiment, the case where the pressure difference between the plasma generation chamber 14 and the sample processing chamber 15 is controlled by controlling the gas supply system 3 and the exhaust system 4 has been described, but this is not limited to this. 13 communication port 13a.

The pressure difference may be changed by changing the size and number of the 13b.

Furthermore, the pressure difference can be changed by differentially pumping the plasma generation chamber and sample processing chamber.

On the other hand, the dielectric covered line 2 is constructed by fixing a dielectric layer 2b to the lower surface of an AI plate 2a that is large enough to cover the upper surface of the reactor l and facing the upper surface of the heat-resistant plate 12. is,
One end of the periphery is connected to the waveguide 5, and the other end has a reflecting plate 2c fixed thereto.

Materials for the dielectric layer 2b include Teflon, polystyrene,
A material with low dielectric loss, such as polyethylene, is used.

The dielectric layer 2b concentrates the electromagnetic field as a surface wave waveguide,
Chamber A6 of the plasma generation chamber 14 through the heat-resistant plate 12. A
Introduced into I.

In the apparatus of the present invention as described above, chamber A0. of the plasma generation chamber 14 in the reactor 1. A. , Sample processing chamber 15
After setting the inside to a predetermined degree of vacuum, the chamber A in the plasma generation chamber 14 is heated while the sample 16 is heated with a heater (not shown).
A reactive gas is supplied to the chamber A0, and a raw material gas for plasma such as Ar is supplied to the chamber A0 through the supply pipes 3a and 3b of the gas supply system 3, respectively. Supply microwave. The Ar gas supplied to the chamber ○ of the plasma generation chamber 14 is excited by a strong electric field and is plasma decomposed, and the reactive gas supplied to the large chamber AI is lightly excited but is not turned into plasma. According to the pressure difference between each chamber A, AI and the sample processing chamber 15, the sample is drawn out into the sample processing chamber 15 through the communication ports 13a and 13b of the partition wall 13, reaches the surface of the sample 16, and undergoes a gas phase reaction to form a film. will be done.

Therefore, since there is no reactive gas in chamber A, no film is generated here (the generation of plasma is maintained stably).

[Test example]

The dimensions and test conditions of reactor 1 are as follows.

The partition wall 13 of the reactor 1 is 5tlS30 with a thickness of 1.
A four-wire plate is used, and the plasma generation chamber 14 has 318 lengths in the direction of microwave propagation and 200 lengths in width, and is divided into approximately 53 lengths in the direction of microwave propagation, which corresponds to 172 wavelengths of the standing wave. Slit-shaped communication ports with a width of 0.1 mm were opened as communication ports 13a and 13b communicating with the sample processing chamber 15, respectively, in the partition wall 13 at the portion facing each chamber A6°A. .

On the other hand, the dielectric covered line 2 is constructed by pasting Teflon as a dielectric material on the lower surface of an Al frame having a width of 600H. The length of Teflon in the microwave propagation direction is 4
84 m, diameter 200B, and thickness 20 mm were used. Also, the distance between the Teflon lower surface and the heat-resistant plate 12 is 80 mm.
m+ closed.

From gas supply system 3, N2 gas is supplied to chamber A0, and chamber A,
As a result, a substantially uniform SiN film was deposited on a 6-inch Si wafer placed in the sample processing chamber 15.

Although the above-mentioned embodiments have been described with reference to the case where they are applied to a CVD apparatus, the present invention is not limited to this, but can also be applied to, for example, an epitaxial growth apparatus, an amorphous silicon manufacturing apparatus, and the formation of an organic polymer film using an organic diammonium. Needless to say, you can get it.

FIG. 3 is a schematic diagram showing another embodiment of the present invention, in which a horn 19 is arranged in the shape of a square pyramid above the heat-resistant plate 12, and a waveguide 5 is vertically connected to the upper end of the horn 19. The structure is such that the microwave is made to enter the heat-resistant plate 12 perpendicularly.

〔effect〕

As described above, in the apparatus of the present invention, the plasma generation chamber is divided into a chamber with a low electric field strength including nodes of microwave standing waves and a chamber with a high electric field strength including an antinode, and reactive gases etc. are Since the plasma is supplied to the sample processing chamber through a small chamber, the film does not adhere to the inner wall of the plasma generation chamber, allowing stable plasma generation to be maintained and high-quality film formation with less ion bombardment. The present invention has excellent effects such as being able to perform processing in a low vacuum where plasma is easily generated and in a high vacuum where there is less contamination.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the apparatus of the present invention, Figure 2 is an explanatory diagram showing the positional relationship between the reaction vessel in the apparatus of the present invention and the waveform of the microwave standing wave formed in its plasma generation chamber, and Figure 3 is It is a schematic diagram which shows another Example of this invention. 1...Reactor 2...Dielectric coated line 3...Gas supply system 4...Exhaust system 5...Waveguide 6...
Microwave oscillator 12... Heat-resistant plate 13... Partition walls 13a, 13b... Communication port 14... Plasma generation chamber 15... Sample processing chamber 16... Sample A
o, A+... Home ownership Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono Mistake 3
figure

Claims (1)

[Claims] 1. A plasma generation chamber at least partially formed of a heat-resistant wall through which microwaves can pass, a sample processing chamber in which a sample is placed, and a microwave standing wave in the plasma generation chamber along the sample processing chamber. a means for introducing microwaves so that the plasma generation chamber is formed, and a chamber with a low electric field strength including nodes of standing waves and a chamber with high electric field strength including an antinode of the standing waves, which are formed by dividing the plasma generation chamber. , is formed of a material that blocks microwaves, is arranged to separate the plasma generation chamber from the sample processing chamber, and connects each of the chambers with low electric field strength and the chamber with high electric field strength to the sample treatment chamber. A plasma processing device characterized by comprising a partition wall having a communication port.