JPH08316198A - Plasma equipment - Google Patents

Abstract

(57) [Summary] [Construction] One microwave oscillator 26, a plurality of dielectric layers 21a and 21b, and a microwave for branching and propagating a microwave from the microwave oscillator 26 to the plurality of dielectric layers 21a and 21b. A plurality of dielectric layers 21a, 21b, each of which is provided with a wave waveguide 23 and a reaction container having a microwave introduction window 4.
Are arranged in parallel, and the dielectric layers 21 are arranged in parallel.
A plasma apparatus in which a reaction vessel is arranged so that the microwave introduction window 4 faces a and 21b. [Effect] A large area substrate such as a glass substrate for a liquid crystal display can be stably and uniformly plasma-treated with an easy structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma device suitable for performing processing such as etching, ashing, and CVD using plasma on semiconductor element substrates, glass substrates for liquid crystal displays and the like.

[0002]

2. Description of the Related Art Plasma generated when energy is externally applied to a reaction gas is widely used in LSI and LCD manufacturing processes. In particular, the dry etching technique using plasma has become an indispensable basic technique for LSI and LCD manufacturing processes.

Although RF (high frequency) of 13.56 MHz is often used as an excitation means for generating plasma, high density plasma can be obtained at low temperature, and the structure and operation of the device are simple. Because of the advantages of
Microwaves are also being used. However, in a conventional plasma device using microwaves, it is difficult to generate uniform plasma in a large area, and thus it is difficult to uniformly process a large-diameter semiconductor substrate and an LCD glass substrate. .

In this regard, the present applicant has proposed, as a plasma device capable of uniformly generating a microwave plasma in a large area, in Japanese Patent Laid-Open Nos. 62-5600 and 62-62.
In Japanese Patent Publication No. 99481, a method using a dielectric layer is proposed.

FIG. 9, FIG. 10 and FIG. 11 are a schematic plan view, a partial vertical sectional view and a side sectional view of a plasma device using this dielectric layer.

In this device, microwaves are introduced from the microwave oscillator 26 into the dielectric layer 21 through the microwave waveguide 23 formed of a waveguide. An electric field is formed in the lower space 20 by the microwave propagating through the dielectric layer 21, the electric field is transmitted through the microwave introduction window 4 and supplied into the reaction chamber 2, and plasma is generated.
The plasma treatment is applied to the surface of the sample S by this plasma.

The dielectric layer has an introduction portion 211 and a taper portion 212.
And a flat plate portion 213. The introduction of microwaves from the microwave waveguide 23 to the dielectric layer 21 is performed by introducing the microwaves from the waveguide into the dielectric layer at the introduction portion 211, expanding the width direction at the taper portion 212, and introducing into the flat plate portion 213. Be seen. By doing so, the microwave can be uniformly propagated in the width direction in the flat plate portion 213 facing the microwave introduction window 4.

Since the plasma device utilizing this dielectric layer generates plasma under the dielectric layer along the traveling direction of the microwave, the microwave introducing port 3 opened at the upper part of the reaction chamber 2 By enlarging the microwave introduction window 4 and the dielectric layer 21 to be sealed, a large-area microwave plasma can be easily generated.

[0009]

In recent years, the size of glass substrates for liquid crystals has increased, and there is an increasing demand for an apparatus capable of uniformly processing glass substrates of 400 mm × 400 mm or more. In the plasma device using this dielectric layer, large-area plasma can be generated by increasing the microwave inlet, the microwave inlet window, and the dielectric layer as described above.

However, if the area of this dielectric layer is increased, the width of the dielectric layer in the taper portion of the dielectric layer can be increased in order to introduce the microwaves uniformly in the width direction of the dielectric layer. It is necessary to take measures such as making the taper angle that widens in the direction more gentle. Therefore, there is a problem that the tapered portion becomes large.

When the area of the dielectric layer becomes large, uneven heating of the dielectric layer due to uneven propagation of microwaves is emphasized, and the in-plane temperature distribution of the dielectric layer becomes uneven,
There is a problem that the dielectric layer is deformed, which adversely affects the reproducibility of the processing speed in the plasma processing.

Further, since the plasma is generated in a state where the inside of the reaction vessel is depressurized, the microwave introduction window is required to have a pressure resistance strength due to a pressure difference inside and outside the reaction vessel. Therefore, when the size of the microwave introduction window becomes large, it is necessary to increase the pressure resistance against the pressure difference between the inside and outside of the reaction container, and it is necessary to make the microwave introduction window thicker.

However, if the microwave introducing window is made thick, the temperature difference between the surface on the reaction chamber side and the surface on the opposite side of the microwave introducing window becomes large due to plasma heating during plasma generation.
There is a problem that the microwave introduction window may be damaged by the thermal strain.

The present invention has been made in view of the above problems, and provides a plasma apparatus capable of stably and uniformly plasma-treating a large-area substrate such as a glass substrate for a liquid crystal display with a simple structure. It is an object of the present invention to provide a plasma device in which the microwave introduction window is less likely to be damaged by thermal strain.

[0015]

The present invention, as shown in FIG. 1, FIG. 2 and FIG.
, A plurality of dielectric layers 21a, 21b, a microwave waveguide 23 for branching and propagating microwaves from the microwave oscillator 26 to the plurality of dielectric layers 21a, 21b, and a reaction vessel 1 having a microwave introduction window 4. A plasma in which a plurality of dielectric layers 21a and 21b are arranged in parallel, and the reaction vessel 1 is arranged such that the microwave introduction windows 4 face the dielectric layers 21a and 21b arranged in parallel. The invention is based on a device, and the present invention is based on FIGS. 5, 6 and 7.
As shown in FIG. 5, a plurality of microwave introduction windows 4 are provided corresponding to the plurality of dielectric layers 21a and 21b.
The gist is a plasma device divided into a and 4b.

[0016]

In the plasma device of the present invention, the dielectric layer facing the microwave introduction window is divided into a plurality of layers, and the microwave waveguide is branched from one microwave oscillator and connected to each of the plurality of dielectric layers. are doing. By doing so, it is possible to easily introduce a uniform microwave in the width direction of the dielectric layer without increasing the tapered portion.

Moreover, since the microwave propagation through the dielectric layer can be made uniform, the dielectric layer is deformed due to the non-uniform heating of the dielectric layer due to the non-uniform propagation of the microwave, and the reproducibility of plasma processing is deteriorated. Can be prevented.

In the plasma device of the present invention, the area of each microwave introduction window can be reduced by dividing the microwave introduction window according to the plurality of dielectric layers. By doing so, it is not necessary to increase the thickness of each microwave introduction window, and the risk of damage due to thermal strain can be reduced.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the plasma device of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic plan view of a plasma device according to an embodiment of the present invention, which illustrates introduction of microwaves into a dielectric layer. The microwave waveguide 23 is composed of a waveguide and is branched into two in the middle. A microwave distributor (not shown) is provided in the middle of the microwave waveguide 23, and the microwaves are equally divided and supplied to the two waveguides. Via this microwave waveguide 23,
The microwave oscillator 26 and the dielectric layers 21a and 21b are connected. Two upper surfaces of the dielectric layers 21a and 21b are covered with a metal plate 22. Fluorine resin such as Teflon (registered trademark) is used for the dielectric layers 21a and 21b.
The metal plate 22 is made of aluminum or the like. Tuners 24a and 24b for matching the microwaves are provided in the microwave waveguide 23, respectively.
In addition, an isolator 25 for removing the reflected wave of the microwave
a and 25b are provided. By providing a tuner and an isolator for each, matching adjustment can be performed independently for each dielectric layer, and the adverse effect of each reflected wave can be eliminated.

After the microwave is oscillated by the microwave oscillator 26, it is branched into two in the middle of the microwave waveguide 23 and introduced into the dielectric layers 21a and 21b, respectively. Then, in each of the dielectric layers 21a and 21b, it is introduced from the waveguide into the dielectric layer in the introduction portions 211a and 211b, expanded in the width direction in the tapered portions 212a and 212b, and introduced into the flat plate portions 213a and 213b. It Thus, the microwaves are uniformly propagated in the flat plate portions 213a and 213b facing the microwave introduction port 3 and the microwave introduction window 4.

FIG. 2 is a schematic partial cross-sectional view of the plasma apparatus of this embodiment, which illustrates the reaction vessel and the arrangement of the reaction vessel and the dielectric layer.

In the figure, reference numeral 1 denotes a hollow rectangular parallelepiped reaction container. The reaction container 1 is formed using a metal such as aluminum (Al). A reaction chamber 2 is provided inside the reaction container 1. A microwave introducing port 3 is opened at the upper part of the reaction vessel 1, and the microwave introducing port 3 is hermetically sealed by sandwiching an O-ring 9 between the microwave introducing window 4 and the upper wall of the reaction vessel 1. It is sealed. The microwave introduction window 4 has heat resistance and microwave transparency, and has a small dielectric loss such as quartz glass (SiO ₂ ), alumina (A ₂
It is formed of a dielectric material such as l ₂ O ₃ ).

In the reaction chamber 2, a sample table 7 on which the sample S is placed is arranged at a position facing the microwave introduction window 4. A gas introduction hole 5 for introducing a reaction gas and an exhaust port 6 connected to an exhaust device (not shown) are provided. A solvent passage 8 is formed on the peripheral wall of the reaction container 1, and the peripheral wall of the reaction container 1 is maintained at a predetermined temperature by circulating a solvent having a predetermined temperature.

Above the reaction container 1, the dielectric layers 21a and 21a face the microwave introduction window 4 and cover it.
b (not shown) is located.

FIG. 3 is a schematic side sectional view of the plasma device of this embodiment. Dielectric layers 21a and 21b are arranged in parallel so as to face the microwave introduction window 4.

The apparatus of this embodiment has a plasma generation area of 50.
The size was 0 mm × 500 mm. The dimensions and materials of the main part are as follows. The microwave inlet 3 is 500 mm × 500 mm. The microwave introducing window 4 is a quartz plate having a size of 600 mm × 600 mm and a thickness of 20 mm. The flat plate portions of the dielectric layers 21a and 21b are 600 mm × 3
It is Teflon having a thickness of 00 mm and a thickness of 20 mm.

A case will be described where the surface of the sample S placed on the sample table is subjected to plasma treatment in the plasma apparatus of the present invention. First, a solvent having a predetermined temperature is circulated in the solvent passage 8. After exhausting from the exhaust port 6 to exhaust the inside of the reaction chamber 2 to a required pressure, the reaction gas is supplied from the gas introduction hole 5 provided in the peripheral wall to bring the inside of the reaction chamber 2 to a predetermined pressure.

A microwave is oscillated by the microwave oscillator 26 and is branched into two waveguides in the middle of the microwave waveguide 23 so that the dielectric layers 21a and 21b respectively.
To be introduced. Space 20 below the dielectric layers 21a and 21b
An electric field is formed in the reaction chamber 2 and the electric field is transmitted through the microwave introduction window 4 and supplied into the reaction chamber 2 to generate plasma. The plasma treatment is applied to the surface of the sample S by this plasma.

The ion current distribution was measured in order to evaluate the plasma uniformity in the plasma apparatus of this example. The measurement was performed in the microwave traveling direction Z centering on the center position of the sample stage and in the Y direction perpendicular thereto. The measurement position is 100 mm from the microwave introduction window. Plasma generation uses Ar gas, pressure 10mT
Orr was performed at a microwave power of 3 kW.

FIG. 4 is a graph showing the measurement result of the ion current distribution. As is clear from FIG. 4, plasma can be generated almost uniformly.

Another embodiment of the plasma device of the present invention will be described with reference to the drawings. FIG. 5, FIG. 6 and FIG. 7 are a schematic plan view, a partial vertical sectional view and a side sectional view of a plasma device according to another embodiment of the present invention.

The present embodiment is different from the previous embodiment in that a beam 31 is provided and the microwave introduction port is divided into two portions 3a and 3b, so that the microwave introduction window is divided into two portions 4a and 4b. And also by the metal wall 30 the dielectric layer 4a,
The difference is that the interference of the microwave propagating through 4b is eliminated. After the microwave is oscillated by the microwave oscillator 26, the microwave is branched into two waveguides in the middle of the microwave waveguide 23 and introduced into the dielectric layers 21a and 21b, respectively, and transmitted through the microwave introduction windows 4a and 4b. And is supplied into the reaction chamber 2 to generate plasma.

The apparatus of this embodiment has a plasma generation area of 50.
The size was 0 mm × 500 mm. The dimensions of the main part are as follows. Microwave inlet 3 is 500 mm
× 210 mm. Microwave introduction window 4 is 620 mm
It is a quartz plate having a thickness of × 290 mm and a thickness of 20 mm. Beam 31
Has a width of 80 mm. The flat plate portions of the dielectric layers 21a and 21b are Teflon having a thickness of 20 mm and a size of 620 mm × 290 mm.

In order to evaluate the plasma uniformity in the plasma apparatus of this embodiment, the ion current distribution was measured as in the previous embodiment. Measurement was performed at a position of 100 mm from the beam in the traveling direction Z of the microwave and the Y direction perpendicular thereto with the center position of the sample stand as the center. As in the previous embodiment, plasma was generated using Ar gas at a pressure of 10 mTorr,
The microwave power was 3 kW.

FIG. 8 is a graph showing the measurement result of the ion current distribution. Despite the presence of the beam 31, plasma can be generated almost uniformly at a position 100 mm away from the beam 31. It is considered that this is because the plasma was sufficiently diffused because it was sufficiently separated from the beam.

[0037]

As described above in detail, in the apparatus of the present invention, a large-area substrate such as a glass substrate for a liquid crystal display can be stably and uniformly plasma-treated with an easy structure. Moreover, since only one microwave oscillator is required, the cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic plan view of an embodiment of a plasma device of the present invention.

FIG. 2 is a schematic partial vertical sectional view of an embodiment of the plasma device of the present invention.

FIG. 3 is a schematic side sectional view of an embodiment of the plasma device of the present invention.

FIG. 4 is a graph showing measurement results of ion current distribution.

FIG. 5 is a schematic plan view of another embodiment of the plasma device of the present invention.

FIG. 6 is a schematic partial vertical cross-sectional view of another embodiment of the plasma device of the present invention.

FIG. 7 is a schematic side sectional view of another embodiment of the plasma device of the present invention.

FIG. 8 is a graph showing measurement results of ion current distribution.

FIG. 9 is a schematic plan view of an example of a conventional plasma device.

FIG. 10 is a schematic partial vertical sectional view of an example of a conventional plasma device.

FIG. 11 is a schematic side sectional view of an example of a conventional plasma device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction container 2 Reaction chamber 3, 3a, 3b Microwave introduction port 4, 4a, 4b Microwave introduction window 5 Gas introduction hole 6 Gas exhaust port 7 Sample stage 8 Solvent flow passage 20, 20a, 20b Space 21, 21a, 21b Dielectric layer 22 Metal plate 23 Microwave waveguide 24, 24a, 24b Tuner 25, 25a, 25b Isolator 26 Microwave oscillator 30 Metal wall 31 Beam 211, 211a, 211b (Dielectric layer) introduction part 212, 212a, 212b ( Tapered part (of dielectric layer) 213, 213a, 213b Flat part (of dielectric layer)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiki Ebata 4-533 Kitahama, Chuo-ku, Osaka-shi, Osaka Sumitomo Metal Industries, Ltd. (72) Inventor Kyoichi Komachi 4-chome, Kitahama, Chuo-ku, Osaka-shi, Osaka 5th 33th Sumitomo Metal Industries, Ltd.

Claims (2)

[Claims] 1. A microwave oscillator, a plurality of dielectric layers, and a microwave waveguide for branching and propagating microwaves from the microwave oscillator to the plurality of dielectric layers.
A reaction container having a microwave introduction window, the plurality of dielectric layers are arranged in parallel, and the reaction container is arranged so that the microwave introduction windows face the dielectric layers arranged in parallel. A plasma device characterized by the above. 2. The plasma device according to claim 1, wherein the microwave introduction window is divided according to the plurality of dielectric layers.