JP2646664B2 - Microwave plasma film deposition equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave plasma film deposition apparatus that can be used in a process of forming a thin film in the semiconductor industry or the like.

2. Description of the Related Art As an example of a conventional metal thin film deposition apparatus using microwaves, a plasma generation chamber and a sample chamber are configured, and a plasma extraction window having a target is provided therebetween to supply gas to both chambers. Applicable plasma film deposition system
It is proposed in 57-1556843. According to this method, low-temperature deposition, which is an advantage of the electron cyclotron resonance (hereinafter referred to as ECR) plasma deposition method, is possible.
Metal compounds and the like are characterized in that a high-quality film having a high adhesion strength can be deposited.

FIG. 3 shows a conventional example of the above-mentioned plasma film deposition apparatus. In the figure, 1 is a plasma generation chamber, and 2 is a sample chamber. Reference numeral 3 denotes a microwave introduction window, which uses quartz glass. The microwave is guided from the rectangular waveguide 4 to the plasma generation chamber 1 through the microwave introduction window 3. In the plasma generation chamber 1, a plasma extraction window 5 is provided opposite to the microwave introduction window 3, and plasma is supplied to a sample stage 8 on which a sample substrate 7 is installed.
Guide up. The sample chamber 2 is connected to an exhaust system 9. A magnetic coil 10 is provided on the outer periphery of the plasma generation chamber 1, and the intensity of the magnetic field generated by the magnetic coil 10 is set so that the condition of ECR resonance by microwave is satisfied in the plasma generation chamber 1. The gas introduction system has two systems, a first gas introduction system 12 for introducing a gas for plasma generation and a second gas introduction system 13 for introducing a source gas to the sample chamber 2. Further, the plasma generating chamber 1 is cooled by passing cooling water through 14 to 15. Further, a target electrode 17 containing a sputtering material 16 is provided so as to surround the plasma flow 6,
It is connected to a power supply 19 for sputtering.

Problems to be Solved by the Invention This metal thin film deposition apparatus using ECR plasma and sputtering is a thin film deposition method that makes use of the advantages of ECR plasma. However, in the case of a thin film having conductivity, metal atoms sputtered from a sputter target diffuse into the plasma generation chamber 1 and a metal thin film is deposited on the microwave introduction window 3 to hinder microwave propagation and stably. There was a problem that the discharge became impossible and the thin film could not be continuously deposited.

The present invention has been made in view of the above problems, and provides a microwave plasma film deposition apparatus for processing a substrate with good reproducibility.

Means for Solving the Problems In order to solve the above problems, the microwave plasma film deposition apparatus of the present invention is connected to the microwave introduction port as a means for transmitting microwaves to the microwave introduction port. A waveguide having a supply port for nitrogen gas, oxygen gas, inert gas or a mixed gas thereof, an insulator for keeping the waveguide in a vacuum, and an influence of a magnetic field of the magnetic coil in the waveguide And a ferromagnetic material provided so as to surround the waveguide so as not to affect the waveguide.

Action The present invention, by the above configuration, nitrogen gas or hydrogen gas supplied from the waveguide, or an inert gas,
The plasma is generated in the plasma generation chamber by the microwave and the magnetic field generated by the magnetic coil, and the plasma is generated. In addition, since the circumference of the waveguide is surrounded by a ferromagnetic material, there is almost no magnetic field in the waveguide, so that no discharge occurs. Therefore, the problem that the microwave is reflected in the waveguide does not occur. Ions, electrons, and radicals of the gas discharged in the plasma generation chamber are transported to the reaction chamber by the action and diffusion of the magnetic field, and decompose the reaction gas supplied to the reaction chamber. The decomposed reaction gas reaches the substrate and forms a film. The reaction gas supplied to the reaction chamber reaches the generation chamber by diffusion, is decomposed, and further reaches the waveguide. However, since nitrogen gas, hydrogen gas, or an inert gas is supplied, the And scatters in the horizontal direction to reach the waveguide wall. In addition, since no discharge occurs in the waveguide, it is adsorbed on the waveguide wall surface at room temperature. As a result, the rate at which the reaction gas reaches the insulator that can transmit microwaves is reduced.

Embodiment Hereinafter, a microwave plasma film deposition apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view of a microwave plasma film deposition apparatus according to a first embodiment of the present invention.

In FIG. 1, a vacuum chamber 20 includes a first simultaneous tube 21, a discharge chamber 22, and a reaction chamber 23. The first coaxial tube 21 has a discharge gas inlet 24, and a reaction chamber 23 has a reaction gas inlet 25, a vacuum exhaust port 26, and a substrate table 28 on which a processing substrate 27 is placed.
An antenna 30 serving to radiate a microwave (in this case, the central conductor 29 is directly extended to the reaction chamber 23) is connected to a central conductor 29 of the first coaxial waveguide 21. A second simultaneous tube 31 is connected to the first coaxial tube 21 via a ceramic plate (for example, alumina) 32 for maintaining the vacuum chamber 20 in a vacuum. 33 is a magnet coil for applying a magnetic field in the axial direction in the discharge chamber 22, and 34 is the first coaxial tube 21.
To block the magnetic field so that there is no magnetic field inside
This is a shielding plate made of a ferromagnetic material (for example, iron) surrounding the coaxial tube 21.

The microwave plasma film deposition apparatus configured as described above will be described with reference to FIG.
The case of depositing a film will be described. The vacuum chamber 20 is maintained at a vacuum of about 5 × 10 ⁻⁴ Torr with 15 SCCM of hydrogen gas flowing from the discharge gas inlet 24 and 30 SCCM of trimethylaluminum (TMA) gas flowing from the reaction gas inlet 25. The hydrogen gas supplied from the discharge gas inlet 25 receives the microwave transmitted through the second coaxial tube 31 and the first coaxial tube 21 and the magnet coil.
The axial magnetic field (875 Gauss) according to 33 satisfies the electron cyclotron (ECR) resonance conditions and discharges. At this time, since there is a shielding plate 34 made of a ferromagnetic material around the first coaxial tube 21 to block the magnetic field, no discharge occurs in the first coaxial tube 21 and microwaves are efficiently transmitted to the discharge chamber 22. Can be supplied. Hydrogen ions, radicals and electrons generated by the discharge in the discharge chamber 22 reach the reaction chamber 23 by the action and diffusion of the magnetic field, and decompose the trimethylaluminum supplied from the reaction gas inlet 25. Decomposed ions, electrons and radicals of trimethylaluminum also reach the processing substrate 27 by the action and diffusion of the magnetic field, and deposit an aluminum film. Also by diffusion,
The decomposed trimethylaluminum gas moved in the direction of the first coaxial tube 21 collides with hydrogen gas molecules supplied from the discharge gas inlet 24, is scattered, and is adsorbed on the wall surface of the first coaxial tube 21 at room temperature. As a result, the ratio reaching the ceramic plate 32 for vacuum sealing is reduced, and almost no film is deposited on the ceramic plate 32, and the film can be deposited with good reproducibility without interrupting the supply of microwaves.

As described above, according to the present embodiment, the first coaxial tube 21 that transmits microwaves to the discharge chamber 22 can be maintained in a vacuum, and a discharge gas is supplied to the first coaxial tube 21. Further, by providing a shield plate 34 made of a ferromagnetic material around the first coaxial waveguide 21, an aluminum film is not easily deposited on the ceramic plate 32, and plasma is not generated in the first coaxial waveguide 21. A film can be deposited with good reproducibility without interrupting the supply of microwaves.

Next, a microwave plasma film deposition apparatus according to a second embodiment of the present invention will be described with reference to the drawings. Second
The figure shows a sectional view of a microwave plasma film deposition apparatus according to a second embodiment of the present invention.

FIG. 2 differs from FIG. 1 in that there is no ferromagnetic shield plate 34, and instead the first coaxial waveguide 21a is made of a ferromagnetic material.

The microwave plasma film deposition apparatus configured as described above will be described with reference to FIG.
The case of depositing a film will be described. Basically, it is the same as in FIG.
SCCM, trimethylaluminum (T
MA) With a gas flow of 30 SCCM, a vacuum of about 5 × 10 ⁻⁴ Torr is maintained. Hydrogen gas supplied from the discharge gas inlet 25 is subjected to electron cyclotron (ECR) resonance by the microwave transmitted through the second coaxial tube 31 and the first coaxial tube 21a and the axial magnetic field (875 Gauss) by the magnet coil 33. The condition is satisfied and discharge occurs. At this time, since the first coaxial tube 21a is made of a ferromagnetic material, the magnetic field is cut off, and there is almost no magnetic field on the first coaxial tube 21a, so that discharge is unlikely to occur and microwaves are efficiently transmitted to the discharge chamber 22. Can be supplied.
Hydrogen ions, radicals and electrons generated by the discharge in the discharge chamber 22 reach the reaction chamber 23 by the action and diffusion of the magnetic field, and decompose the trimethylaluminum supplied from the reaction gas inlet 25. Decomposed ions, electrons and radicals of trimethylaluminum also reach the processing substrate 27 by the action and diffusion of the magnetic field, and deposit an aluminum film. Further, the decomposed trimethylaluminum gas that has moved in the direction of the first coaxial tube 21a due to the diffusion collides with the hydrogen gas molecules supplied from the discharge gas inlet 24, is scattered, and is dispersed on the inner wall surface of the first coaxial tube 21a at room temperature. Adsorbed. As a result, the number of cases reaching the ceramic plate for vacuum sealing is reduced, the film hardly deposits on the ceramic plate 31, and the film can be deposited with good reproducibility without interrupting the supply of microwaves.

As described above, according to the present embodiment, the first coaxial tube 21a that transmits microwaves to the discharge chamber 22 can be maintained in a vacuum, and the discharge gas is supplied to the first coaxial tube 21a. Further, since the first coaxial waveguide 21a is made of a ferromagnetic material, an aluminum film is less likely to be deposited on the ceramic plate 32, and no plasma is generated in the first coaxial waveguide 21a. A film can be deposited with good reproducibility without interfering.

In the above embodiment, the case of depositing an aluminum film has been described. However, the present invention can be applied to deposition of a high melting point metal such as tungsten and other films.

In the above embodiment, the gas flowing from the discharge gas inlet 24 is hydrogen, but may be nitrogen or an inert gas depending on the film to be deposited.

In the above embodiment, the ceramic plate 32 is used.
Any insulator that can transmit microwaves and maintain a vacuum can be used.

Needless to say, the first coaxial waveguides 21 and 21a have the same effect even if they are waveguides.

Effects of the Invention As described above, according to the present invention, the first coaxial waveguide for transmitting microwaves to the discharge chamber is kept in a vacuum with an insulator, and a discharge gas is supplied to the first coaxial waveguide. By surrounding the first coaxial waveguide with a ferromagnetic material or by making the first coaxial waveguide itself a ferromagnetic material, it is difficult to deposit a film on the insulator and to prevent generation of plasma in the first coaxial waveguide. Thus, a microwave can be supplied efficiently, and a film can be deposited with good reproducibility.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a microwave plasma film deposition apparatus according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a microwave plasma film deposition apparatus according to a second embodiment of the present invention, and FIG. It is sectional drawing of the conventional microwave plasma film deposition apparatus. 21, 21a ... first coaxial tube, 22 ... discharge chamber, 23 ... reaction chamber,
24 …… Discharge gas inlet, 25 …… Reaction gas inlet, 26 ……
Vacuum exhaust port, 27 Processing substrate, 30 Antenna, 32
Ceramic plate, 33 ... Magnet coil, 34 ... Shield plate made of ferromagnetic.

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-63-278221 (JP, A) JP-A-63-137168 (JP, A) JP-A-1-100276 (JP, A) JP-A-59-1984 103331 (JP, A)

Claims (3)

(57) [Claims] 1. A plasma generation chamber for introducing a microwave through a microwave introduction port to generate plasma by a magnetic field generated by a magnetic coil, a reaction chamber connected to the plasma generation chamber and having a reaction gas introduction port and a vacuum exhaust port. And a microwave plasma film deposition apparatus provided with a substrate stage on which a substrate is placed in the reaction chamber, wherein the microwave introduction port is connected to the microwave introduction port as transmission means for transmitting microwaves to the microwave introduction port; A first waveguide having a supply port for a gas, an oxygen gas, an inert gas or a mixed gas thereof, an insulator for keeping the first waveguide in a vacuum, and the first waveguide passing through the insulator. A second waveguide for transmitting microwaves to the tube, and a ferromagnetic provided around the first waveguide to prevent the magnetic field of the magnetic coil from affecting the first waveguide. Microwave plasma film deposition apparatus comprising a. 2. A coaxial waveguide as a first waveguide, wherein a central conductor of the coaxial waveguide extends to the plasma generation chamber, and an extension of the central conductor is formed by a straight rod or a spiral coil. 2. The microwave plasma film deposition apparatus according to claim 1, wherein the apparatus is used as an antenna for a plasma. 3. The microwave plasma film deposition apparatus according to claim 1, wherein the first waveguide itself is made of a ferromagnetic material instead of the ferromagnetic material provided around the first waveguide. .