JPS63114985A - Plasma device - Google Patents

Abstract

PURPOSE:To enhance the efficiency of effective utilization of a gaseous raw material by providing a gas transport pipe along a plasma flow between a window for drawing out plasma and a placing base of a sample and surely introducing the gaseous raw material into the flow of plasma. CONSTITUTION:A gas transport pipe 6 is provided to the interval reaching a placing base 5 of a sample from a window 1d for drawing out plasma generat ed in a plasma formation chamber 1. The inner diameter of the upper end of the gas transport pipe 6 is set nearly equally to the diameter of the window 1d and the inner diameter of the lower end part thereof is set nearly equally to the diameter of the placing base 5 by expanding the inner diameter toward the lower end part. Plasma generated in the plasma formation chamber 1 is projected around the sample S put in a reaction chamber 3 through the window 1d by means of action of the magnetic field formed with an exciting coil 4. Process gas fed through a gas feed pipe 3g is directly introduced into a plasma flow through the gas transport pipe 6. Therefore chance of bringing the process gas into contact with the plasma flow is increased and thereby the process gas is not wasted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is mainly directed to CVD (CVD) for manufacturing highly integrated semiconductor devices.
Chemical Vapor Deposition
), etching equipment, sputtering equipment, etc.

[Prior art]

Plasma equipment using electron cyclotron resonance can generate highly active plasma at low gas pressure, allows a wide range of ion energies to be selected, and has a large ion current, with excellent directionality and uniformity of ion flow. Because of these advantages, research and development are progressing on it as an indispensable part of the film formation and etching processes required to manufacture highly integrated semiconductor devices.

FIG. 3 is a vertical cross-sectional view of a conventional plasma device using electron cyclotron resonance configured as a CVD device.
31 indicates a plasma generation chamber.

The plasma generation chamber 31 has a double structure around the surrounding wall and is equipped with a cooling water circulation chamber 31a, and a microwave inlet 31c sealed with a quartz glass plate 31b in the center of the upper wall, and a microwave inlet 31c sealed with a quartz glass plate 31b in the center of the lower wall. A circular plasma extraction window 31d is provided at a position facing the microwave inlet 31c, and one end of a waveguide 32 whose other end is connected to a microwave oscillator (not shown) is connected to the microwave inlet 31c. In addition, a reaction chamber 33 is arranged facing the plasma extraction window 31d, and is further surrounded by a plasma generation chamber 31 and one end of a waveguide 32 connected to the plasma generation chamber 31. A coil 34 is provided.

A disk-shaped mounting table 38 is disposed in the reaction chamber 33 so as to face the plasma extraction window 31d, and a disk-shaped sample 37 such as a wafer is placed thereon as is or by means such as electrostatic adsorption. The reaction chamber 33 is removably placed therein, and an exhaust port 33a connected to an exhaust device (not shown) is opened in the lower wall of the reaction chamber 33. 31g.

33g is a raw material gas supply pipe.

In such a CVD apparatus, while heating and maintaining the sample 37 at a predetermined temperature, the source gas is supplied into the plasma generation chamber 315 and the reaction chamber 33, which are set at a required degree of vacuum, while the excitation coil 34 is heated and maintained. A microwave is introduced into the plasma generation chamber 31 while forming a magnetic field to generate plasma, which is then passed through the plasma extraction window 31 formed by the exciting coil 34
d A diverging magnetic field whose magnetic flux density decreases toward the front reaction chamber 33 side is projected around the sample 37 on the mounting table 38 in the reaction chamber 33 to form a film on the surface of the sample 37 (specially (No. 155535, 1973).

[Problem that the invention seeks to solve]

By the way, in general, in this type of plasma apparatus, when forming a SiO film on the surface of the sample 37, for example, 0□ is connected to the gas supply pipe 31g, and 5il1 is connected to the gas supply pipe 33g.
4 respectively and decompose these gases.

The film is formed by turning it into plasma. However, in the conventional plasma apparatus, the plasma generated in the plasma generation chamber 31 is guided into the reaction chamber 33 through the circular plasma extraction window 31d, and the projection area is gradually expanded.
The plasma is projected onto a wider circular area around the sample 37 on 8, but since the area of the reaction chamber 33 is wider than this plasma projection area, the gas supply pipe on the wall of the reaction chamber 33 The separation method between the 33g opening and the ion projection area is large (SiL supplied from the gas supply pipe 33g).
Most of the ions are exhausted through the exhaust port 33a without crossing the ion projection area, and the contribution rate to film formation, that is, the utilization efficiency is low.
There was also a problem that the film formation rate of Sing was slow.

The present invention has been made in view of the above circumstances, and its purpose is to provide a plasma device that can significantly improve the efficiency of effective utilization of raw material gas.

[Means for solving problems]

In the first aspect of the present invention, a gas transport pipe is disposed along the plasma flow between the plasma extraction window of the plasma generation chamber and the sample mounting table. In the second aspect of the present invention, the peripheral wall of the sample chamber itself is formed along the plasma flow.

[Effect]

This makes it possible in the present invention to reliably introduce the raw material gas supplied from the gas supply pipe into the plasma flow.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention configured as a CVD apparatus will be specifically described below with reference to the drawings. FIG. 1 is a longitudinal cross-sectional view of a plasma device according to the present invention (hereinafter referred to as the device of the present invention), in which 1 is a plasma generation chamber, 2 is a waveguide, and 3 is a sample chamber in which film formation is performed on a sample S. A barrel reaction chamber, 4 indicates an excitation coil.

The plasma generation chamber 1 is made of stainless steel and is formed into a hollow cylindrical shape with a double-walled surrounding wall and a water-cooled jacket Ha, and a microwave inlet 1c closed with a quartz glass plate ib in the center of the upper wall. In addition, a microwave extraction window 1d is provided at the center of the lower wall at a position facing the microwave introduction port 1c, one end of the waveguide 2 is connected to the microwave introduction port IC, and a plasma extraction window 1d is provided.
A reaction chamber 3 is disposed facing this, and an excitation coil 4 is disposed around the plasma generation chamber 1 and one end of a waveguide 2 connected thereto.

1g indicates a plasma maintenance gas supply pipe 1h connected to the plasma generation chamber 1, and li indicates a cooling water supply pipe and a discharge pipe connected to the water cooling jacket 1a, respectively.

The other end of the waveguide 2 is connected to a microwave oscillator (not shown), and the microwaves emitted here are introduced into the plasma generation chamber 1 through the microwave introduction port 1c. The excitation coil 4 is connected to a DC power source (not shown), and by passing a DC current, it forms a magnetic field so that plasma can be generated by introducing microwaves into the plasma generation chamber l, and also generates a magnetic field toward the reaction chamber 3 side. A diverging magnetic field with a low magnetic flux density is formed, and the plasma generated in the plasma generation chamber 1 is introduced into the reaction chamber 3.

The reaction chamber 3 is formed into a hollow cylindrical shape, and has a plasma extraction window 1.
An exhaust port 3a connected to an exhaust device (not shown) is opened in the bottom wall facing d, and a sample mounting table 5 is disposed in the reaction chamber 3 at a position facing the plasma extraction window 1d. .

In the present invention, a gas transport pipe 6 is disposed between the plasma extraction window 1d and the mounting table 5. This gas transport pipe 6 has a cylindrical shape, and the inner diameter at the upper end is set approximately equal to the diameter of the plasma extraction window 1d, and the inner diameter increases from there toward the lower end. The upper end is fixed concentrically to the opening of the plasma extraction window 1d on the reaction chamber side, and the upper end is placed above the mounting table 5 with a required distance between it and this. They are extended to be located at intervals. 3
A gas supply pipe g for supplying process gas extends through the side wall of the reaction chamber 3 and the peripheral wall of the gas transport pipe 6, and its tip is opened at the inner surface of the peripheral wall of the gas transport pipe 6.

Therefore, in the apparatus of the present invention, the sample S is mounted on the mounting table 5 of the reaction chamber 3, heated and maintained at a predetermined temperature, and the inside of the plasma generation chamber 12 and the reaction chamber 3 is set to the required degree of vacuum. rear,
Raw material gas is supplied into the plasma generation chamber l1 reaction chamber 3 through the gas supply pipes 1g and 3g, a direct current is passed through the excitation coil 4, and microwaves are introduced through the waveguide 2 to establish electron cyclotron resonance conditions. Establish it and generate plasma. The generated plasma is projected around the sample S in the reaction chamber 3 through the plasma extraction window 1d by the action of the magnetic field formed by the excitation coil 4.

In such an embodiment, the process gas supplied from the gas supply pipe 3g is guided directly into the plasma flow through the gas transport pipe 6 arranged along the plasma projection area, and there is no chance of contact with the plasma flow. There is no waste in the process gas.

FIG. 2 is a schematic sectional view showing another embodiment of the present invention, in which the gas transport pipe shown in FIG. 1 is constructed by the peripheral wall of the reaction chamber itself.

That is, the portion of the peripheral wall of the reaction chamber 13 that corresponds between the plasma extraction window 1d and the mounting table 5 is set so that its inner diameter at the upper end is approximately equal to the diameter of the plasma extraction window 1d, and from there the lower end The diameter of the inner wall expands toward the side so as to substantially follow the plasma flow, and the inner diameter of the lower end is set to be approximately equal to the diameter of the mounting table 5 to form the transport pipe section 13b, and is connected to the transport pipe section 13b. A mounting table 5 is placed on the lower end of the lever.
It is configured by forming a cylindrical portion 13c in which the An exhaust port 13a is opened at the center of the lower end of the cylindrical portion 13c, and a gas pipe 13g for supplying process gas is connected to the peripheral wall of the intermediate portion of the transport pipe portion 13b.

The other configurations are substantially the same as the embodiment shown in FIG. 1,
Corresponding parts are denoted by the same reference numerals and their explanation will be omitted.

Next, the results of a comparative test between the device of the present invention and the conventional device will be explained using specific numerical values.

0□ from gas supply pipes 1g and 31g 35 s c, c
into the plasma generation chamber l, 31 at a ratio of m, and a gas supply pipe 3g.

5iHa was introduced from 13g and 33g into the reaction chamber 3°13, 33 at a rate of 28 sec, and the gas pressure was increased to 1,4
When SiO□ was deposited on a Si wafer on a 5°35 mounting table while maintaining the pressure at 3×10-” Torr and the microwave input was 300 W, the gas utilization efficiency was 8.5 with the conventional device (Fig. 3). %, and the deposition rate was 1,960 people/min, but in the apparatus of the present invention (each example shown in FIGS. 1 and 3), the gas utilization efficiency was improved to 11.5%, and the deposition rate was 2,650 people/min.

In such embodiments of the present invention, the volume of the reaction chamber is significantly reduced, making it possible to reduce the size of the entire apparatus, as well as increasing the effective utilization efficiency and further reducing raw material gas. be.

Although each of the embodiments described above shows a configuration in which the apparatus of the present invention is applied to a CVO apparatus, the present invention is not limited to this in any way, and it goes without saying that the apparatus can also be applied to, for example, an etching apparatus, a sputtering apparatus, and the like.

〔effect〕

As described above, the present invention includes a gas transport pipe or a transport pipe portion whose cross-sectional area increases from the plasma draw-out window toward the processing table along the plasma flow between the plasma draw-out window and the sample mounting table. Therefore, wasteful discharge of the supplied raw material gas is reduced, the effective utilization efficiency is high, and process processing efficiency such as film formation and etching is improved accordingly. Further, if such a gas transport pipe is configured to be used also on the peripheral wall of the reaction chamber itself, the sample chamber becomes extremely compact, and the present invention has excellent effects such as further saving of raw material gas.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view showing an embodiment of the present invention;
- FIG. 2 is a schematic vertical sectional view showing another embodiment of the present invention;
FIG. 3 is a schematic vertical sectional view of a conventional device. 1... Plasma generation chamber 1d... Plasma drawer window 1
g...Gas supply pipe 2...Waveguide 3, 13...
Reaction chambers 3g, 13g...Gas supply pipe 4...Excitation coil 6...Transportation pipe 13b...Gas transport pipe section
S...Sample time Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono No. I E No. z Figure

Claims (1)

[Claims] 1. In a plasma apparatus provided with a sample chamber equipped with a mounting table facing a plasma extraction window of a plasma generation chamber that generates plasma using electron cyclotron resonance, the plasma extraction window and the sample A plasma device characterized by comprising a gas transport pipe that is installed along a plasma flow across a mounting table in a room, and whose cross-sectional area increases as it goes from a plasma extraction window toward the mounting table. 2. The plasma device according to claim 1, wherein the gas transport pipe has a gas inlet opening in its peripheral wall. 3. In a plasma apparatus having a sample chamber equipped with a mounting table facing the plasma extraction window of a plasma generation chamber that generates plasma using electron cyclotron resonance, the peripheral wall of the sample chamber is connected to the plasma extraction window and the mounting table. What is claimed is: 1. A plasma device comprising: a transport pipe portion formed such that its cross-sectional area increases along the plasma flow from the plasma extraction window toward the mounting table. 4. The plasma apparatus according to claim 3, wherein a gas inlet is opened in the peripheral wall of the sample chamber.