JPH05144772A - Plasma apparatus - Google Patents

Abstract

PURPOSE:To prevent the ununiformity in density of generated plasma even when a gas flow velocity and a gas exhaustion velocity are increased in a microwave plasma apparatus for processing a substrate. CONSTITUTION:A gas introducing pipe 6 is connected with a waveguide 2, the gas entering waveguide 2 is then led to a plasma generating chamber 17 depending on the flow 12 of gas and the gas is equally supplied into the region of plasma 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a structure of a plasma device,
In particular, it relates to the structure of the gas introduction pipe of the plasma generation chamber.

[0002]

2. Description of the Related Art A conventional plasma apparatus will be described by taking an ECR plasma etching apparatus, which is one of plasma apparatuses using a waveguide, as an example for the sake of clarity. In the ECR plasma etching apparatus, plasma is generated by the following mechanism. That is, the microwave generated by the transmitter tube 1 (usually 2.45 GH
z) is introduced into the sample chamber using the waveguide 2, and 875G
In the magnetic field of (2.45 GHz), the electric field energy is supplied by resonating with the electron that makes a turning motion (electron cyclotron resonance).

The electrons that make a swirling motion collide with gas molecules to ionize the gas molecules and generate a plasma 11 composed of ions and electrons. Since the electrons make a swirling motion, the collision frequency is higher than that in the absence of a magnetic field, and stable plasma is generated even at a low pressure of the order of 10 ⁻⁴ Torr, which is difficult when no magnetic field is present.

At this time, the material to be etched can be physically and chemically etched by using a reactive gas as the gas. In particular, by performing the etching at a low pressure of 10 ⁻⁴ Torr, the radical density, which is the main factor of the side etching, can be kept small, and anisotropic processing can be performed even with a small ion energy.

Since electron cyclotron resonance (ECR) occurs only in a region having a magnetic field strength of 875 G, this region is called an ECR region. By forming this region in a large area in a planar shape, it is possible to form a uniform large area. The planar plasma 11 can be generated. When the substrate 10 is arranged so as to be in contact with the planar plasma 11, even a large area substrate is uniformly etched.

In etching and deposition using plasma, it is important to efficiently exhaust reaction products on the surface of the substrate, and usually a large evacuation device is used to ensure a sufficient evacuation speed. There is. At the same time, in order to maintain the pressure of 10 ⁻⁴ to 10 ⁻³ Torr used in the ECR plasma device, the flow rate of gas is increased and adjusted.

As shown in FIG. 2, in the ECR plasma etching apparatus, the waveguide 2 is usually connected to a portion of the plasma generating chamber 17 which is located directly above the substrate 10, and is guided by the introduced microwave 5. The generated plasma 11 is located directly above the substrate 10. Since the waveguide 2 is located directly above the substrate 10, the gas introduction pipe 6 is connected to the portion of the plasma generation chamber 18 that is off the substrate 10. In the figure, 16 is an evacuation device, and 13 is a flow of exhaust gas. Portions common in structure to the present invention are designated by the same reference numerals and description thereof will be omitted.

[0008]

When a vacuum exhaust device with a large displacement is used to increase the exhaust velocity of the reaction product and the gas inflow velocity is increased, the residence time of gas molecules in the plasma generation chamber 17 is increased. Since the length of the gas is shortened and sufficient diffusion does not occur until the gas molecules are exhausted, the gas is coarse and dense in the plasma generation chamber 17. Gas introduction pipe 6
Is connected to the position deviating from above the center of the board,
The density of the gas is likely to occur in the direction parallel to the substrate, resulting in non-uniformity in the density and flow of the generated plasma, which affects the etching rate and the processed shape.

An object of the present invention is to provide a plasma device that solves the above-mentioned problems in a plasma device in which plasma is generated in a plasma generation chamber by a microwave introduced using a waveguide to process a substrate. It is in.

[0010]

To achieve the above object, in a plasma device according to the present invention, a plasma is generated by using an electromagnetic wave introduced into a plasma generation chamber through a waveguide, and the plasma is utilized. In a plasma apparatus for processing a sample, a gas introducing pipe is connected to the waveguide, and the waveguide is used as a gas introducing passage.

[0011]

When the gas is introduced from the waveguide, the gas molecules are uniformly supplied to the plasma generation region even if the diffusion of the gas molecules does not sufficiently occur, and the plasma having a uniform density can be obtained. Also, if the waveguide is located right above the substrate, the average movement direction of gas molecules will be almost vertical on the entire surface of the substrate, and the processing shape in the substrate plane due to the difference in the movement direction of gas molecules It is possible to reduce the variation of

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, the plasma device has a microwave generation tube 1 and a vacuum exhaust device 6 connected to a plasma generation chamber 17 containing a substrate support 9. The microwave transmission tube 1 and the plasma generation chamber 17 are connected by a waveguide 2 having a microwave introduction window 4, and the waveguide 2 at the mounting portion of the plasma generation chamber 17 is expanded to form a tapered waveguide. It is 3. Around the plasma generating chamber 17, a main coil 7 and a sub coil 8 are installed. The substrate support 9 is connected to a high frequency power supply 15 and sealed by a shield 14.

In the present invention, the gas introduction pipe 6 is connected to the waveguide 2 immediately below the microwave introduction window 4.

Microwave 5 generated by transmitting tube 1
Is introduced into the plasma generation chamber 17, and the gas introduced into the waveguide 2 from the gas introduction pipe 6 is introduced into the plasma generation chamber 17 according to the flow 12 of the gas. By colliding with the gas molecules, the gas molecules are ionized to generate plasma, contact the substrate 10 mounted on the substrate support 9, further sucked by the vacuum exhaust device 13, and flow out as a flow 13 of exhaust gas. .

In the present invention, even if the diffusion of gas molecules does not sufficiently occur, the gas molecules are uniformly supplied to the plasma generation region, and the plasma 11 having a uniform density can be formed and acted on the substrate 10. .

[0016]

As described above, according to the present invention, in the plasma apparatus for generating plasma by the microwave introduced by the waveguide and processing the substrate, the reaction product can be efficiently exhausted. Even if the amount of exhaust gas and the introduction of a large amount of gas are introduced, uniform plasma can be generated and the in-plane uniformity of etching or film deposition on the substrate can be improved. As a result, etching or film deposition on a large area substrate can be performed uniformly, and productivity is improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a plasma device according to the present invention.

FIG. 2 is an explanatory diagram of a conventional plasma device that does not use the present invention.

[Explanation of symbols]

 1 Microwave Sending Tube 2 Waveguide 3 Tapered Waveguide 4 Microwave Introducing Window 5 Microwave 6 Gas Introducing Tube 7 Main Coil 8 Subcoil 9 Substrate Support 10 Substrate 11 Plasma 12 Gas Flow 13 Exhaust Gas Flow 14 Shield 15 High frequency power supply 16 Vacuum exhaust device 17 Plasma generation chamber

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H05H 1/46 9014-2G // C23C 14/34 8414-4K

Claims (1)

[Claims] 1. In a plasma apparatus for generating a plasma by using an electromagnetic wave introduced into a plasma generation chamber through a waveguide and processing a sample using the plasma, a gas introduction pipe is connected to the waveguide. A plasma apparatus, wherein the waveguide is used together with a gas introduction path.