JPS6366826A - High-frequency ion source appalied device - Google Patents

Abstract

PURPOSE:To suppress the high-frequency intrusion into ion extracting power supplies and stabilize the operation as an ion source by inserting a high-frequency attenuator reducing high-frequency propagation between an ion extracting device and both pole terminals of the power supplies feeding the voltage to the ion extracting device. CONSTITUTION:An ion extracting device is constituted of an extracting electrode 2 applied with the positive voltage with respect to the container potential of a machining chamber 4 and an accelerating electrode 3 applied with the negative voltage with respect to the container potential of the machining chamber 4, and the electric field for accelerating positive ions from a plasma chamber 1 toward the machining chamber 4 is formed between the electrodes 2 and 3. DC stabilized power supplied 15, 15' are connected to individual electrodes via high-frequency blocking filters 14, 14' and a filter 14'' between the container of the machining chamber 4 and the DC power supplies. In addition, if high-frequency blocking filters 17, 17' and insulating transformers 15, 15' are inserted in commercial-frequency power supplies 18, 18' for the DC stabilized power supplies, the high-frequency current intrusion into grounding cables 19, 19' of the commercial-frequency power supplies is blocked.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a high frequency ion source application device that generates plasma using high frequency waves and applies ions extracted from the plasma, and in particular, relates to a high frequency ion source application device that generates plasma using high frequency waves and applies ions extracted from the plasma. This invention relates to a high frequency ion source suitable for.

[Conventional technology]

Conventionally, the technology of generating plasma using high frequency waves and using it as an ion source is described in Journal of Vacuum Science and Technology, Volume A3 (3), (1985), pages 1218 to 1221.
VacuuIII Science and Techno
logic A3 (3) (1985) ppl 21
8-1221). However, the method for supplying voltage to the ion extraction device is not described.

Further, Japanese Patent Publication No. 60-30098 discloses a method in which when applying a DC voltage bias to a high frequency power source, the high frequency power source and the DC power source are not connected directly but are connected through a filter circuit. However, this is a case where it is necessary to supply voltage to the same electrode from a high frequency power source and a DC power source, and this is different from the configuration intended by the present invention.

Furthermore, as shown in FIG. 2, in Japanese Patent Application Laid-open No. 58-100430, high frequency power is supplied from a high frequency power source 7 between a mesh electrode 9 and a flat electrode 25, and a sample loading electrode 2
An embodiment is shown in which another mesh-like electrode 3 is inserted between the mesh-like electrode 1 and the mesh-like electrode 9, and a negative DC voltage is applied to this electrode from the DC power supply 15. It is disclosed that a filter 14 is inserted between the shaped electrodes 3. According to this embodiment, the terminal 26 of the sample loading electrode 21 and the positive terminal 26 of the DC power supply 15
' is connected as the ground point of the plasma processing apparatus itself, and since the sample loading electrode 21 and the mesh electrode 3 are coupled through the stray capacitance 25, the circuit 2
7 is formed. By inserting the filter 14,
High frequency current flowing through this circuit can be attenuated and blocked. However, in general, the DC power supply 15 receives power from the commercial frequency power supply 18, and in that case, one end 20 of the power supply is grounded. Therefore, in this case, a circuit 28 is formed from the sample loading electrode 21 to the earth point 20 through the DC power supply 15 via the terminals 26, 26', and the high frequency current passes through the DC power supply. This point was not taken into consideration in the embodiment disclosed in Japanese Patent Application Laid-Open No. 58-100430.

[Problem that the invention attempts to solve]

In the above-mentioned conventional technology, in an ion source that generates plasma using high frequency waves and extracts ions from the plasma, consideration is given to the fact that high-frequency current from the ion extraction device intrudes into the power supply that supplies voltage to the ion extraction device. However, when the high frequency power increases, there is a problem in that the operation of the ion extraction power source is adversely affected, such as fluctuations in the supply voltage.

An object of the present invention is to provide a high-frequency ion source application device that suppresses high-frequency waves from entering a power source for ion extraction and stabilizes the operation of the ion source.

[Means for solving problems]

The above purpose is to insert a high frequency blocking filter between the ion extraction device and the power supply that supplies voltage to it, so that the ion extraction device acts as an antenna and suppresses high frequencies from entering the extraction power source. This is achieved by

[Effect]

The high frequency for plasma generation is usually 13.56 MHz, which is allocated for industrial use, and this high frequency ionizes gas and turns it into plasma.

The ion extractor uses a DC electric field to extract ions from the accelerated plasma generation chamber to the processing chamber. By obtaining a stable DC electric field, it is possible to exhibit high quality and stable characteristics as an ion source. For this purpose, it is necessary that the power supply that supplies DC voltage to the extraction device operates stably, and for this reason, a stabilized power supply is generally used. When high frequencies enter this power supply, effects such as voltage fluctuations occur, but by inserting a filter that attenuates high frequencies between the extraction device and the terminals of the DC power supply, high frequencies can be suppressed from entering the stabilized power supply. As a result, stable ion source operation can be ensured.

〔Example〕

Hereinafter, details of the present invention will be explained using the drawings.

FIG. 1 shows an embodiment of a high frequency ion source application device.

a plasma chamber 1 for generating plasma by high frequency;
It consists of an extraction electrode 2.3 for extracting ions from the plasma chamber 1 and a processing chamber 4 for processing the material surface layer with the extracted ions, and the processing chamber 4 is connected to an exhaust device (not shown) through an exhaust passage 5. The plasma chamber 1 is connected to a gas supply device (not shown) through a gas inlet 6. The space within the apparatus consisting of the plasma chamber 1 and the processing chamber 4 is evacuated to a pressure of 10-8 Torr or less by a vacuum evacuation device, and then the sample gas is
″″Torr, and connect the high frequency power source 7 to the matching circuit 8.
high frequency power is supplied to the coil 9 through the coil 9 to generate plasma. The high frequency circuit is insulated from the plasma chamber 1 by an insulator of 1°. Moreover, the power supply circuit of the high frequency power supply 7 is
It is generally insulated and inductively coupled from a commercial frequency power supply 12 by an isolation transformer 11, and further a high frequency blocking filter 13 is inserted.

The ion extraction device is made up of an extraction electrode 2 to which a positive polarity voltage is applied with respect to the container potential of the processing chamber 4, and an acceleration electrode 3 to which a negative polarity voltage is applied to the container potential of the processing chamber 4. An electric field is formed between and 3 for accelerating positive ions from the plasma chamber 1 toward the processing chamber 4. A DC stabilized power source 15° 15' is connected to each electrode via a high frequency blocking filter 1.4.14' according to the present invention and a filter 14'I between the container of the processing chamber 4 and the DC power source. has been done.

Also, a high frequency blocking filter 17. '7' and isolation transformer 15
．． 15' may be inserted, increasing the effect of blocking high frequency current from flowing into the ground [19, 19' of the commercial frequency power supply.

The ion beam 19 extracted into the processing chamber 4 by the ion extraction device is irradiated onto the sample 21 held by the holder 20 within the processing chamber 4, thereby etching, milling, etc. the surface layer of the sample.

According to this embodiment, the coil 9 is arranged in the plasma chamber 1, and the high frequency circuit can be sufficiently shielded from electromagnetic waves, and the ion extraction electrodes 2, 3 and the plasma chamber 1,
The container of the processing chamber 4 will be placed in the high frequency electromagnetic wave radiation space. Therefore, if the high frequency blocking filter 14
．． If 14' and 14'' were not present, the electrodes 2 and 3 and the container would act as an antenna.

High-frequency electromagnetic waves invade a DC stabilized power supply, generating a high induced electric field, which can destroy electronic components with relatively low withstand voltage specifications or cause them to malfunction.

According to this embodiment, it is possible to suppress high frequency waves from entering the power supply section of the ion extraction device from the high frequency power source via the ion extraction device.

In the embodiment shown in FIG. 1, the coil for plasma generation is placed inside the plasma chamber, but the present invention can also be applied to a case where the coil is placed outside the plasma chamber.

FIG. 3 shows a high frequency ion source application device similar to the embodiment shown in FIG. 1, in which a high frequency blocking filter 41 is inserted between the container of the plasma chamber 1 and the ion extraction electrode 2. Plasma is generated between the coil 9 and the container of the plasma chamber 1, so that its resistance and stray capacitance pass through! , and a high-frequency current flows. This is effective in more effectively attenuating high frequency components entering from the container of the plasma chamber 1. Further, filters 14, 14', 14', and 14# are inserted on both pole sides of the DC power supplies 15, 15' to more reliably suppress the intrusion of high frequency current.

Further, in the embodiment shown in FIG. 3, a capacitor 42 is inserted between the high frequency power source 7 and the coil 9. This is to prevent direct current from flowing from the electrode 2 and the container of the plasma chamber 1 to the coil 9 through the plasma resistance when a DC voltage is supplied to the extraction electrode 2. A capacitor 43 of the matching circuit 8 is connected to one end of the coil 9, and conventionally, direct current flowing through this circuit is blocked. Compared to the structure shown in FIG. 1, the high frequency power supply is not charged to a high potential by direct current, so it is safe.

FIG. 4 shows a basic embodiment of a high frequency blocking filter, in which an inductance 51 is inserted in series with the circuit, and both ends of the inductance 51 are inserted in series with the circuit.
Alternatively, a capacitor 52 is connected between one end and the ground potential. It is preferable to connect this filter circuit to each device via a coaxial cable 53.

FIGS. 5 and 6 show other embodiments of the high frequency ion source application device. In this implementation, permanent magnets 30 are arranged radially outside the plasma chamber 1. The magnet 30 is
As shown in FIG. 5, an even number of permanent magnets are arranged so that their polarities are in the radial direction, and the polarities of adjacent magnets are in opposite directions. With such a magnet arrangement, a magnetic field is formed near the inner wall surface of the plasma chamber 1 in which adjacent magnetic fields have opposite polarities. If such a magnetic field exists near the wall of the plasma chamber, the plasma generated by the high-frequency coil 9 will have difficulty escaping to the wall, improving the plasma density.Furthermore, the density distribution within the plasma chamber will be made uniform, and ions will The ion beam extracted into the processing chamber 4 by the extraction device can be made homogeneous and have a high current density.

In this embodiment as well, eight frequency blocking filters 14.14' and 14 are used to prevent zero frequency from entering the DC stabilized power supply 15.15' that supplies DC voltage to the ion extraction electrodes 2 and 3.
', 14''.

According to this embodiment, an ion source application device with an ion source that generates plasma using high frequency can stably supply a large-area ion beam with uniform ion density, thereby providing an ion source application device with high processing efficiency. can.

Furthermore, although the present invention has been described with respect to a high frequency of 13.56 MHz, the present invention is not limited to this frequency, and can be sufficiently applied to high frequencies in the microwave region, and similar effects can be achieved. can.

〔Effect of the invention〕

According to the present invention, stable ion extraction characteristics can be obtained, and it is possible to perform processing and ion implantation with excellent performance as an ion source application device.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing one embodiment of the high-frequency ion source applied device of the present invention, Fig. 2 is a schematic diagram showing a conventional ion source applied device, and Fig. 3 is a cross-sectional view showing another embodiment of the present invention. Figure, 4th
FIG. 5 is a circuit diagram showing an example of a high frequency blocking filter, FIG. 5 is a sectional view showing still another embodiment of the present invention, and FIG. 1... Plasma chamber, 2, 3... Ion extraction electrode, 4... Processing chamber, 7... High frequency power supply, 9... Coil, 14° 14' 14. ' , 14'... High frequency blocking filter, 15.15'... Ion extraction power supply.

Claims (1)

[Scope of Claims] 1. A high-frequency ion source consisting of a plasma chamber that generates plasma using high-frequency waves, a high-frequency power source that supplies high-frequency current, an ion extractor that extracts ions from the plasma chamber, and its power source; In a high frequency ion source application device comprising a chamber with a device for utilizing ions generated from the source, reducing high frequency propagation between the ion extraction device and the polar terminals of a power supply that supplies voltage to the ion extraction device. A high-frequency ion source application device characterized in that a high-frequency attenuation device is inserted. 2. According to claim 1, magnets are arranged radially around the plasma chamber so that their polarities are in the radial direction, and the polarities of adjacent magnets are in opposite directions. High frequency ion source application equipment. 3. The high-frequency ion source applied device according to claim 1 or 2, characterized in that a capacitor is inserted in all of the circuits connecting the high-frequency circuit in the plasma chamber and the high-frequency power source.