JP2000008169A - Antenna for generating discharge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of particles caused by the sputtering of a vacuum vessel by plasma without hardly changing a hardware. SOLUTION: An antenna 13 for generating discharge is formed in such a manner that the cross section vertical to the longitudinal direction has a flat shape. Moreover, this antenna 13 is arranged in such a manner that flat faces 131 and 132 are made almost parallel to the side wall 1a of a discharge generating part 112. In this way, in the antenna 13 for generating discharge, the face opposite to the side wall 1a of the discharge generating part 112 is formed in such a manner that plural electric lines of force outputted from this face or inputted to this face are made almost parallel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an annular discharge generating antenna for generating a discharge for generating plasma by an electrodeless discharge method.

[0002]

2. Description of the Related Art In recent years, CVD (Chemical Vapor Deposition) for forming a predetermined thin film on the surface of a wafer using a chemical reaction.
In the ition) device, plasma is attracting attention as energy for promoting a chemical reaction.

[0003] In order to realize this plasma CVD apparatus, it is necessary to generate plasma. In order to generate this plasma, it is necessary to generate a discharge.

Conventionally, various methods have been considered as a method for generating the discharge. One of them is an electrodeless discharge generation method. This electrodeless discharge generation method
In this method, a high-frequency power is applied to a discharge generating antenna to generate a discharge. This electrodeless discharge generation method has attracted attention as a discharge generation method capable of generating high-density plasma.

As an electrodeless discharge generation method, for example, an inductive coupling method (hereinafter referred to as “ICP (Inductive Coupled
Plasma) method. ). This ICP method is
This is a method in which high-frequency power is applied to a discharge generating antenna and a discharge is generated by high-frequency electromagnetic induction.

In a conventional plasma CVD apparatus using an ICP method as an electrodeless discharge generation method, a one-turn antenna formed of a copper tube is often used as a discharge generation antenna. In this case, a copper tube having a diameter of about １ ／ to ／ inch is usually used as the copper tube.

[0007]

However, in such a configuration, the reaction chamber (vacuum vessel) that provides a sealed film formation space, in other words, a plasma generation space, is sputtered by plasma, and There is a problem that particles are generated.

This will be described with reference to FIG. FIG.
1 is a side sectional view of a part of a plasma CVD apparatus. In the figure, 31 indicates a reaction vessel, and 32 indicates a discharge generating antenna. In addition, x1 indicates a plurality of lines of electric force output from or input to the surface of the discharge generating antenna 32, and x2 indicates an equipotential surface formed by the lines of electric force x1.

As shown, a plurality of electric lines of force x1 extend radially around the central axis of the discharge generating antenna 32. As a result, the line of electric force x1 is concentrated on a part of the reaction vessel 31. As a result, the electric field increases in a part of the reaction vessel 31. Thereby, the reaction vessel 31 is sputtered by plasma at this portion. As a result, the reaction vessel 3
Not only is the life of the device 1 shortened, but also particles are generated.

In order to solve this problem, conventionally, a plasma CVD apparatus using an antenna having a plurality of turns as a discharge generating antenna has been considered.

However, in such a configuration, there is a problem that a change in hardware of the plasma CVD apparatus becomes large.

That is, as a discharge generating antenna, 1
When using a turn antenna,
For example, a power supply having a frequency of 13.56 MHz is used. On the other hand, when using a two-turn antenna,
For example, a 2 MHz power supply is used. When an antenna having three or more turns is used, for example, 400 KHz
Power supply is used.

Thus, in such a configuration, it is necessary to change not only the discharge generating antenna but also the high frequency power supply. As a result, in such a configuration,
The change in hardware of the plasma CVD apparatus becomes large.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a discharge generating antenna capable of preventing generation of particles due to sputtering of a vacuum vessel by plasma without changing hardware of the apparatus so much. I do.

[0015]

According to a first aspect of the present invention, there is provided a discharge-generating antenna which is hermetically sealed in an annular discharge-generating antenna for generating a plasma-generating discharge by an electrodeless discharge method. The surface facing the vacuum vessel for providing a plasma generation space is formed such that a plurality of lines of electric force output from or input to this surface extend substantially in parallel. And

In the above configuration, a plurality of lines of electric force output from or input to the surface facing the vacuum vessel extend substantially in parallel. Thus, the plurality of lines of electric force do not concentrate in a part of the vacuum vessel. As a result, the electric field provided by the plurality of lines of electric force does not increase in a part of the vacuum vessel. Thus, it is possible to prevent generation of particles due to sputtering by plasma only by changing the discharge generating antenna without changing the high frequency power supply.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a side sectional view showing the structure of the first embodiment of the present invention. Before describing the configuration of the discharge generating antenna shown in FIG. 1, an example of the configuration and operation of a plasma CVD apparatus using this antenna will be described.

FIG. 3 is a sectional view showing an example of the configuration of the plasma CVD apparatus. In the drawing, a plasma CVD apparatus using a one-turn ICP type antenna as a discharge generation antenna is shown as a representative.

The plasma CVD apparatus shown in FIG.
, A chuck section 12, a discharge generating antenna 13, and a high-frequency oscillator 14.

Here, the reaction vessel 11 provides a closed reaction space for film formation. In other words, it provides a closed plasma generation space. This reaction vessel 11 is constituted by a vacuum vessel. The chuck section 12
Holds the film-forming wafer W. Further, the discharge generating antenna 13 generates a discharge for plasma generation. Further, the high-frequency oscillator 14 generates high-frequency power to be applied to the discharge generating antenna 13.

The reaction vessel 11 is formed, for example, in a cylindrical shape. This cylindrical reaction vessel 11 has a central axis Z
Are arranged so as to face the vertical direction. The reaction vessel 11 has a film forming unit 111 and a discharge generating unit 112. In the film forming unit 111, a film forming process is performed. In the discharge generator 112, a discharge for plasma generation is generated. These are formed coaxially. in this case,
The film forming unit 111 is positioned below, and the discharge generating unit 11
2 is positioned upward. Also, the film forming unit 111
Is set to be larger than the diameter of the discharge generating section 112.

The reaction vessel 11 is made of metal except for the side wall 1a of the discharge generating section 112. On the other hand, the side wall 1a of the discharge generating section 112 is formed of a dielectric such as quartz. This is to reduce high frequency loss. Thus, the side wall 1a of the discharge generating section 112 is a dielectric window.

The chuck section 12 is provided on the upper surface of the bottom plate 2a of the reaction vessel 11. A wafer W to be processed is placed on the upper surface of the chuck section 12.

The discharge generating antenna 13 is disposed so as to surround the side wall 1 a of the discharge generating section 112.
In this case, the antenna 13 is disposed coaxially with the discharge generating section 112 and in contact with the side wall 1a. The antenna 13 is disposed, for example, so as to be located at the axial center of the discharge generating section 112 with respect to the side wall 1a.

FIG. 4 is a perspective view showing the overall shape of the discharge generating antenna 13. As shown in FIG. As illustrated, the discharge generating antenna 13 is formed in an annular shape. Both ends of the antenna 13 are connected to a high-frequency oscillator 14.

In the above configuration, when performing the film forming process, first, the wafer W to be processed is placed on the upper surface of the chuck section 12. Further, the atmosphere inside the reaction vessel 11 is evacuated. When the pressure inside the processing container 11 reaches a predetermined pressure by this vacuum evacuation process, the reaction gas is supplied into the reaction container 11. Further, high frequency power is applied from the high frequency oscillator 14 to the discharge generating antenna 13. Thereby, plasma is formed inside the reaction vessel 11 by high-frequency electromagnetic induction. As a result, the processed wafer W
A predetermined thin film is formed on the surface of the substrate.

The above is the configuration and operation of the plasma CVD apparatus provided with the discharge generating antenna 13 of the present embodiment.

Next, the configuration of the discharge generating antenna 13 of the present embodiment will be described with reference to FIG. FIG. 1 is an enlarged side sectional view showing a configuration of a portion surrounded by a circle A in FIG.

As shown in FIG.
Is configured such that a cross section perpendicular to the length direction has a flat shape. The antenna 13 is, for example,
It is formed by a copper tube. Furthermore, this antenna 13
Is that the two flat surfaces 131 and 132 are
Are arranged substantially parallel to the side wall 1a. In other words, the flat surfaces 131 and 132 are provided so as to be substantially parallel to the central axis z of the reaction vessel 11.

In the above configuration, referring to FIG.
The operation will be described. FIG. 2 is a diagram showing distribution of lines of electric force in the present embodiment.

When high-frequency power is applied to the discharge generating antenna 13, a plurality of electric lines of force x1 are output from the surface of the antenna 13 or a plurality of electric lines of electric force x1 are input to the surface. The plurality of lines of electric force x1 are perpendicular to the surface of the discharge generating antenna 13. As a result, the plurality of electric lines of force x1 output from or input to the flat surface 132 (the surface facing the side wall 1a of the discharge generating portion 112) 132 inside the antenna 13 extend substantially in parallel.
As a result, the plurality of lines of electric force P are
Substantially perpendicularly across the side wall 1a.

In other words, in the above configuration, bar-shaped charges parallel to the side wall 1 a of the discharge generating section 112 are formed on the flat surface 132 of the discharge generating antenna 13. As a result, the electric lines of force x1 output from the flat surface 132 or input to the flat surface 132 extend substantially in parallel. as a result,
The plurality of electric lines of force x1 are
crosses a substantially vertically.

According to the present embodiment described in detail above, the discharge generating antenna 13 is formed such that the cross section perpendicular to the length direction has a flat shape. Further, the antenna 13 is disposed such that the flat surfaces 131 and 132 are substantially parallel to the side wall 1 a of the discharge generating section 112. As a result, in the discharge generating antenna 13, the surface (flat surface 132) facing the side wall 1 a of the discharge generating portion 112 extends substantially in parallel with the plurality of lines of electric force x <b> 1 output from or input to this surface. It is formed to exist.

As a result, it is possible to prevent a plurality of lines of electric force x1 from being concentrated on a part of the side wall 1a of the discharge generating part 112, and to prevent the electric field from becoming strong at this part. Accordingly, it is possible to prevent the generation of particles due to the side wall 1a being sputtered by the plasma only by changing the discharge generating antenna 13 without changing the high frequency power supply 14. As a result, it is possible to prevent the generation of particles due to sputtering by plasma without changing the hardware much.

FIG. 5 is a side sectional view showing the structure of the second embodiment of the present invention. In the figure, reference numeral 21 denotes a discharge generating antenna according to the present embodiment. This antenna 21
Is disposed at the axial center of the reaction vessel 11 with respect to the side wall 1a of the discharge generating section 112, as in the previous embodiment.

The discharge generating antenna 21 has an antenna body 211 and a conductor band 212. Here, the antenna main body 211 is formed in a ring shape. The antenna body 211 is formed such that a cross section perpendicular to the length direction is circular. The antenna body 2
Reference numeral 11 is made of, for example, a copper tube.

The conductor band 212 is formed in an annular shape.
The conductor band 212 is attached to an inner surface of the antenna body 211. In this case, the conductor band 212
Are mounted so as to be substantially parallel to the side wall 1a of the discharge generating section 112. The conductor band 212 is formed of, for example, a copper plate.

Even in such a configuration, the surface of the discharge generating antenna 21 facing the side wall 1a of the discharge generating portion 112 has a plurality of lines of electric force x1 output from or input to this surface as shown in FIG. It is formed so as to extend almost in parallel as shown. Thus, the plurality of electric lines of force x1 do not concentrate on a part of the side wall 1a. As a result, generation of particles due to sputtering can be prevented without changing the hardware much.

FIG. 7 is a side sectional view showing the configuration of the third embodiment of the present invention. In the figure, reference numeral 22 denotes the discharge generating antenna of the present embodiment.

In the above embodiment, the case where the discharge generating antennas 13 and 21 are provided in the discharge generating unit 112 has been described. On the other hand, in the present embodiment, as shown in FIG. 7, the discharge generating antenna 22 is disposed so as to extend between the film forming unit 111 and the discharge generating unit 112.

In this case, the discharge generating antenna 22 is formed so as to have a flat cross section, for example, as in the first embodiment. Also, this antenna 22
Is deformed according to the external shape of the boundary between the film forming unit 111 and the discharge generating unit 112. In the case of the illustrated example, the side wall 1a of the discharge generating unit 112 and the top plate 3a of the film forming unit 111
Are formed at right angles. For this reason, the antenna 22 is also formed so that the cross section becomes a right angle.
Thus, the antenna 22 has, as surfaces facing the reaction vessel 11, a flat surface 221 facing the side wall 1 a of the discharge generating unit 112 and a flat surface 222 facing the top plate 3 a of the film forming unit 111.

Also in such a configuration, in the discharge generating antenna 22, the surface (flat surface 221) facing the side wall 1a of the discharge generating portion 112 has a plurality of lines of electric force output from or input to this surface. x1 is formed so as to extend almost in parallel as shown in FIG. This allows
The plurality of lines of electric force x1 do not concentrate on a part of the side wall 1a.

Similarly, in the discharge generating antenna 22, the surface (the flat surface 22) of the film forming section 111 facing the top plate 3 a
2) is formed such that a plurality of electric lines of force x1 output from or input to this surface extend substantially in parallel as shown in FIG. Thus, the plurality of electric lines of force x1 do not concentrate on a part of the top plate 3a.

As described above, in the present embodiment, generation of particles due to sputtering can be prevented without changing the hardware much.

Although the three embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

(1) For example, in the above embodiment, the surfaces of the discharge generating antennas 13, 21, 22 facing the side wall 1a of the discharge generating unit 112 and the top plate 3a of the film forming unit 111 are parallel to these. Has been described. However, the present invention may be arranged to be inclined. Even in such a configuration, since the plurality of lines of electric force output from or input to the opposing surface extend substantially in parallel, the top wall of the side wall 1a of the discharge generating unit 112 and the film forming unit 111 It is possible to prevent the line of electric force x1 from being concentrated at a part of the plate 3a. Thereby, generation of particles due to sputtering by plasma can be prevented.

(2) In the above embodiment, the case where the present invention is applied to a discharge generating antenna provided outside the reaction vessel 11 has been described. However, the present invention can also be applied to a discharge generating antenna disposed inside the reaction vessel 11. In this case, the outer surface of the discharge generating antenna is formed such that the lines of electric force output from or input to this surface extend substantially in parallel. In short, the present invention is not limited as long as the surface facing the reaction vessel 11 is formed so that the lines of electric force output from or input to this surface extend substantially in parallel.

(3) In the above embodiment, the case where the present invention is applied to a one-turn antenna for generating discharge has been described. However, the present invention can also be applied to an antenna for generating a discharge of two or more turns.

FIG. 9 is a side sectional view showing a configuration of a plasma CVD apparatus using, for example, a two-turn discharge generating antenna 23, and FIG. 10 is a perspective view showing an external configuration of the antenna 23. Similarly, FIG. 11 shows, for example, plasma CVD using a four-turn discharge generating antenna 24.
FIG. 12 is a side sectional view showing a configuration of the device, and FIG. 12 is a perspective view showing an external configuration of the antenna 23.

The present invention can be applied to these two or more turns of the discharge generating antennas 23 and 24. As shown in FIG. 11, the four-turn discharge generating antenna 24 is formed, for example, in a spiral shape instead of a coil shape. In these figures, as the antennas 23 and 24, antennas having the same shape as in the first embodiment are shown as representatives.

(4) In the above embodiment, the case where the present invention is applied to an ICP type discharge generating antenna has been described. However, the present invention can also be applied to a discharge generating antenna of an electrodeless discharge method other than the ICP method. For example, the present invention can be applied to a helicon type discharge generating antenna.

(5) In addition, it goes without saying that the present invention can be variously modified and implemented without departing from the gist thereof.

[0054]

As described in detail above, according to the first aspect of the present invention, the surface facing the processing vessel has a plurality of lines of electric force output from or input to this surface. It is formed so as to be parallel. Thus, it is possible to prevent the plurality of lines of electric force from being concentrated on a part of the processing container. As a result, it is possible to prevent generation of particles due to sputtering of a part of the processing container by plasma.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a side sectional view for explaining the operation of the first exemplary embodiment of the present invention.

FIG. 3 is a side sectional view showing a configuration of an example of a plasma CVD apparatus using the discharge generating antenna according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing an external configuration of a discharge generation antenna according to the first embodiment of the present invention.

FIG. 5 is a side sectional view showing a configuration of a second exemplary embodiment of the present invention.

FIG. 6 is a side sectional view for explaining the operation of the second exemplary embodiment of the present invention.

FIG. 7 is a side sectional view showing a configuration of a third exemplary embodiment of the present invention.

FIG. 8 is a side sectional view for explaining the operation of the third embodiment of the present invention.

FIG. 9 is a side sectional view showing an example of a configuration of a plasma CVD apparatus having a two-turn discharge generation antenna to which the present invention can be applied.

FIG. 10 is a perspective view showing an external configuration of a two-turn discharge generating antenna.

FIG. 11 is a side sectional view showing an example of the configuration of a plasma CVD apparatus having a 4-turn discharge generating antenna to which the present invention can be applied.

FIG. 12 is a perspective view showing an external configuration of a four-turn discharge generating antenna.

FIG. 13 is a side sectional view showing a configuration of a conventional discharge generating antenna.

[Explanation of symbols]

11: reaction vessel, 12: chuck part, 13, 21,
2, 23, 24 ... discharge generating antenna, 14 ... high frequency oscillator, 111 ... film forming unit, 112 ... discharge generating unit, 131,
132 ... flat surface, 211 ... antenna body, 212 ... conductor band, 221, 222 ... flat surface, 1a ... side wall, 2a ... bottom plate, 3a ... top plate.

Claims (1)

[Claims] An annular discharge generating antenna for generating a discharge for plasma generation by an electrodeless discharge method, wherein a surface facing a vacuum vessel for providing a sealed plasma generation space has an output or output from this surface. A discharge generating antenna, wherein a plurality of lines of electric force input to this surface are formed so as to extend substantially in parallel.