JP2007266005A - Spiral resonant device for plasma generation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spiral resonant device for plasma generation applied for a plasma treatment device giving treatment such as etching, ashing or CVD on a semiconductor substrate or the like, and improved for enabling to easily fit resonant characteristics coping with changes of treatment conditions. <P>SOLUTION: The spiral resonant device for plasma generation is equipped with a resonator (1) comprising a container (11) constituted to reduce pressure and supplied gas for plasma, a resonant coil (12), and an outer shield (13) grounded electrically, and a high-frequency power supply (2) for supplying high-frequency power to the resonant coil (12). The resonant coil (12) is constituted to select a grounding position according to treatment conditions to be matched between the load impedance of the resonator (1) and the impedance of the high-frequency power supply (2) side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention is a spiral resonator for plasma generation applied to a plasma processing apparatus that performs processing such as etching, ashing, and CVD on a semiconductor substrate and the like, and easily adapts resonance characteristics in response to changes in processing conditions. The present invention relates to a spiral resonator for plasma generation that can be performed.

The plasma processing apparatus is used for various dry processes such as dry etching, ion etching, ashing, and plasma deposition on a semiconductor substrate. Among these types of processing, for example, in CVD processing, it is required to promote reaction by radicals and to reduce ion damage as much as possible. That is, excessive ions cause mixing of materials between layers in the substrate, destruction of oxides, invasion of contaminants, phenotypic changes, and the like. Moreover, it is preferable to avoid ion bombardment that brings about low selectivity in an etching process or the like that prescribes the selection ratio with high accuracy.

As a result of diligent studies focusing on obtaining a low-potential plasma, the present inventors induced a standing wave by a coil that resonates in all-wavelength mode (helical resonance coil), and generated an induced electric field in the decompression vessel. Therefore, the technology related to the helical resonance device that can cancel the phase voltage and the antiphase voltage from each other and excite a plasma having a very low potential by inductive coupling at the phase voltage switching point, that is, a node where the potential is substantially zero. The patent application has already been filed as “Plasma Discharge Treatment Method by Inductive Coupling”.

Special Table 2000-501568

By the way, in the helical resonance apparatus as described above, when applied to only one type of processing, the resonance characteristics (resonance frequency and impedance) may be set to be constant in advance. In this case, the resistance component of the plasma itself and the capacitive coupling between the voltage part of the resonant coil and the plasma differ depending on the type of plasma (processing conditions). This causes a problem that the plasma potential is increased. In particular, mismatching of the load impedance of the plasma generation circuit with respect to the power supply side impedance due to plasma capacitive coupling or inductive coupling causes a reduction in effective load power.

However, the conventional coaxial power supply type or counter electrode type plasma apparatus is provided with an LC network circuit (matching circuit) for adjusting impedance fluctuations in the plasma generation circuit on the container side and increasing the power transfer efficiency. . However, since the matching circuit itself consumes power because it functions as a part of the plasma generation circuit, and the response speed of the variable capacitor is slow and the plasma state always fluctuates. The reality is that consistency is not achieved.

The present invention has been made in order to further enhance the utility of the above-described helical resonance apparatus, and its purpose is to generate plasma applied to a plasma processing apparatus that performs processes such as etching, ashing, and CVD on a semiconductor substrate and the like. An object of the present invention is to provide a spiral resonator for plasma generation which is improved so that the resonance characteristics can be easily adapted in response to changes in processing conditions.

In order to solve the above problems, a spiral resonator for plasma generation according to the present invention includes a container configured to be depressurized and supplied with a plasma gas, a resonance coil wound around the outer periphery of the container, A resonator comprising an outer shield disposed on the outer periphery of the resonance coil and electrically grounded; and a high-frequency power source for supplying high-frequency power of a predetermined frequency to the resonance coil; and In the spiral resonator for plasma generation, the length of which is set to an integral multiple of one wavelength at the predetermined frequency or a length corresponding to a half wavelength or a quarter wavelength, the resonant coil has a load impedance of the resonator. The grounding position can be selected according to the processing conditions so as to match the impedance on the high-frequency power source side.

In other words, the structure in which the grounding position can be selected in the resonance coil can immediately match the load impedance of the resonator with the impedance on the high frequency power supply side according to the processing conditions. In addition, high frequency power can be supplied to the maximum.

In the above-described plasma generating helical resonance apparatus, the grounding position of the resonance coil is switched by a vacuum relay interposed between the resonance coil and the outer shield in order to more easily select the grounding position of the resonance coil. It is preferable that it is configured.

Further, in each of the above-described spiral resonators for generating plasma, the reflected wave power detected by the reflected wave power meter installed on the output side of the high frequency power supply is minimized in order to further increase the power transfer efficiency. A frequency matching unit for adjusting the oscillation frequency may be attached as described above.

Further, in each of the above-described spiral resonators for generating plasma, in order to further increase the power transfer efficiency, the high-frequency power source has a phase difference between the voltage and current detected by the phase detector installed on the output side thereof. A frequency matching unit that adjusts the oscillation frequency so as to be 0 ° may be provided.

According to the spiral resonator for plasma generation according to the present invention, the grounding positions of a plurality of resonance coils provided corresponding to several preset processing conditions can be selected, and the resonator can be changed according to changes in the processing conditions. The load impedance on the side can be matched immediately, so there is no need to make initial adjustments every time the processing conditions are changed, and it is possible to respond quickly when the process is changed, and optimal resonance in the resonator Characteristics can be obtained and high-frequency power can be supplied to the maximum.

In addition, a frequency generator that adjusts the oscillation frequency so that the reflected wave power is minimized, a spiral resonator for plasma generation with a high-frequency power supply, and oscillation so that the phase difference between voltage and current is 0 ° According to the plasma generating helical resonance device in which the frequency matching device for adjusting the frequency is attached to the high frequency power supply, the frequency matching device can resonate accurately in response to a slight shift in the resonance state when the helical resonance device is operated. Since the high frequency power of the frequency is output to the high frequency power source, the power transfer efficiency can be further maximized. Therefore, a more accurate standing wave can be formed, and a stable plasma with a very low potential can be maintained.

An embodiment of a spiral resonator for plasma generation according to the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an outline of a spiral resonator for plasma generation applied to a plasma processing apparatus. FIG. 2 is a block diagram illustrating an example of a ground position selection unit in the resonance coil. 3 to 5 are waveform diagrams showing the relationship between the grounding position of the resonance coil and the electrical characteristics of the resonator. 6 and 7 are circuit block diagrams each showing a configuration example of a frequency matching unit provided in a high-frequency power source. Hereinafter, in the description of the embodiments, the spiral resonator for plasma generation is abbreviated as “spiral resonator”. Further, a semiconductor substrate or a semiconductor element as an object to be processed is abbreviated as “substrate”.

The helical resonance apparatus of the present invention is an apparatus mainly applied to a plasma processing apparatus. As shown in FIG. 1, a container (11) configured to be depressurized and supplied with plasma gas, and the container A resonator (1) comprising a resonance coil (12) wound around the outer periphery and an outer shield (13) disposed on the outer periphery of the resonance coil and electrically grounded, and the resonance coil (12). A high frequency power supply (2) for supplying high frequency power of a predetermined frequency is provided.

The container (11) is usually a so-called chamber formed in a cylindrical shape with high-purity quartz glass or ceramics. When applied to a plasma processing apparatus, the container (11) is usually arranged so that its axis is vertical, and the upper and lower ends are hermetically sealed by a top plate (42) and a substrate processing chamber (5) of the plasma processing apparatus described later. Sealed. Below the container (11) (substrate processing chamber of the plasma apparatus), an exhaust pipe (41) connected to a vacuum pump and for evacuating the inside of the container (11) is provided, and an upper part of the container (11) ( The top plate (42)) is provided with a gas supply pipe (43) that extends from the material gas supply facility and supplies a required plasma gas.

Since the resonant coil (12) forms a standing wave having a predetermined wavelength, the winding diameter, the winding pitch, and the number of turns are set so as to resonate in a constant wavelength mode. That is, the electrical length of the resonance coil (12) is an integral multiple (1 times, 2 times,...), Half wavelength or 1/4 wavelength of one wavelength at a predetermined frequency of power supplied from the high frequency power source (2). Is set to a length corresponding to.

Specifically, the resonance coil (12) takes into consideration the applied power, the generated magnetic field strength, the outer shape of the applied device, and the like, for example, 0.01 kHz to 800 kHz to 50 MHz and high frequency power of 0.5 to 5 kW. In order to generate a magnetic field of about 10 gauss, it has an effective sectional area of 50 to 300 mm ² and a coil diameter of 200 to 500 mm, and is wound about 2 to 60 times on the outer peripheral side of the container (1). The As a material constituting the resonance coil (12), a copper pipe, a copper thin plate, an aluminum pipe, an aluminum thin plate, a material obtained by evaporating copper or aluminum on a polymer belt, or the like is used. The resonance coil (12) is formed of an insulating material in a flat plate shape and is supported by a plurality of supports vertically provided on an upper end surface of a base plate (4) of a plasma processing apparatus described later.

Further, both ends of the resonance coil (12) are electrically grounded as fixed grounds. Usually, one end of the resonance coil (12) is a movable tap for fine adjustment of the electrical length of the resonance coil during the initial device assembly. Grounded via (15). Reference numeral (14) in FIG. 1 indicates the other fixed ground. Further, a waveform adjustment circuit comprising a coil and a shield is provided at one end (or the other end or both ends) of the resonance coil (12) so that the phase and antiphase currents flow symmetrically with respect to the electrical midpoint of the resonance coil (12). May be inserted. Such a waveform adjusting circuit is configured as an open circuit by setting the end of the resonance coil (12) to an electrically disconnected state or an electrically equivalent state. Further, the end of the resonance coil (12) may be ungrounded by a choke series resistor and may be DC-connected to a fixed reference potential.

The outer shield (13) is provided to shield an electric field outside the resonance coil (12) and to form a capacitance component necessary for forming a resonance circuit with the resonance coil (12). The outer shield (13) is generally configured in a cylindrical shape using a conductive material such as aluminum alloy, copper or copper alloy. The outer shield (13) is disposed about 5 to 150 mm away from the outer periphery of the resonance coil (12). In general, the outer shield (13) is grounded so that the potential is equal to both ends of the resonance coil (12). However, in order to accurately set the resonance number of the resonance coil (12), the outer shield (13). One or both ends of the tap may be adjustable in tap position, or a trimming capacitance may be inserted between the resonant coil (12) and the outer shield (13).

As the high-frequency power source (2), various power sources such as an Rf generator can be used as long as the power source can supply power of a voltage and frequency necessary for the resonator (1). For example, a high frequency generator capable of supplying power of about 0.5 to 5 kW at a frequency of 80 kHz to 800 MHz is used for the plasma processing apparatus including the resonator (1).

Specifically, examples of the power source include a fixed frequency type high frequency power source (frequency: 27.12 MHz, output: 3 kW) known as a trade name “CX-3000” manufactured by Comdel Inc. By using a high-power, high-bandwidth amplification known as the product name “TCCX3500” manufactured by IFI together with a pulse generator of 0-50 MHz known as the product name “HP116A” manufactured by Hewlett-Packard Company, 800 kHz to 50 MHz. A variable frequency power source capable of 2 kW output in the frequency range of can be configured.

The high-frequency power source (2) usually includes a control circuit including at least a preamplifier for defining an output, and an amplifier for amplifying to a predetermined output. That is, in the high frequency power source (2), the control circuit controls the output of the amplifier based on the output condition set in advance through the operation panel, and the amplifier transmits the transmission line (12) to the resonance coil (12) of the resonance device (1). 25) to output a constant high frequency power. The transmission line (25) is connected to a predetermined position between both grounded ends of the resonance coil (12) via a movable tap (28) in order to finely adjust the feeding position at the time of initial device assembly. May be.

By the way, the plasma generation circuit of the resonator (1) constituted by the resonance coil (12) is an RLC parallel resonance circuit, and the wavelength of the high-frequency power source (2) and the electrical length of the resonance coil (12) are the same. In this case, the resonance condition of the resonator (1) is that the reactance component created by the capacitive component and the inductive component of the resonator (1) is canceled out and becomes a pure resistance. However, in the resonator (1), capacitive coupling between the voltage part of the resonance coil (12) and the generated plasma or inductive coupling between the container (11) and the plasma depends on processing conditions (plasma type). Because of the difference, each time the processing conditions are changed, the actual impedance in the resonator (1) slightly varies.

Therefore, in the present invention, in order to quickly respond to the change in the processing conditions, the resonance coil (12) is configured so that the load impedance of the resonator (1) matches the impedance on the high frequency power source (2) side. The grounding position can be selected according to the situation. That is, in the helical resonance apparatus of the present invention, as shown in FIG. 2, a plurality of ground terminals of the resonance coil (12) including a fixed ground are provided corresponding to some preset process conditions. In operation, the ground terminal of the resonance coil (12) is selected according to the process conditions. With such a configuration, in the helical resonance apparatus of the present invention, the load impedance on the resonator (1) side can be optimally maintained regardless of changes in process conditions.

Specifically, as shown in FIG. 2, the grounding position of the resonance coil (12) can be switched by a vacuum relay (16) interposed between the resonance coil (12) and the outer shield (13). ing. As is well known, the vacuum relay (16) is a relay in which a solenoid and contacts are accommodated in a vacuum vessel, and is configured to open and close by the operation of a general relay of an external control circuit. Such a vacuum relay (16) is inserted in, for example, two places between the resonance coil (12) and the outer shield (13). The insertion positions are positions where the impedance of the resonator (1) is 50 ohms, for example, according to the scheduled process conditions. Thereby, the grounding position of the resonance coil (12) including the fixed ground (14) can be selected from, for example, three according to the change of the processing conditions.

The helical resonance apparatus of the present invention is applied to a high-frequency electrodeless discharge type plasma processing apparatus that performs dry processing such as etching, ashing, and CVD on a substrate or the like. As shown in FIG. 1, the plasma processing apparatus is configured by disposing the resonator (1) of the above-described helical resonator on a horizontal base plate (4) configured as a gantry. Under the resonator (1), a substrate processing chamber (5) formed, for example, in a substantially bottomed cylindrical shape with a short axis is provided through the opening of the base plate (4) to accommodate the substrate (W). And in a state continuous with the container (11).

The substrate processing chamber (5) is provided with a short-axis cylindrical susceptor (6) that holds the substrate (W) horizontally. The susceptor (6) may be provided with a commonly used electrostatic chuck. Further, the susceptor (6) may be configured to be movable up and down in order to load and unload the substrate (W) by a substrate transport mechanism (not shown). The substrate (W) is loaded and discharged through a gate valve (not shown) provided on the peripheral surface of the substrate processing chamber (5).

The inside of the container (11) of the spiral resonance apparatus and the substrate processing chamber (5) are configured to be depressurized to a predetermined degree of vacuum through the exhaust pipe (41) attached to the bottom of the substrate processing chamber. In addition, the material gas for plasma generation is supplied to the inside of the container (11) and the substrate processing chamber (5) through the gas supply pipe (43) provided on the top plate (42) at the upper end of the container (11). It is made like that.

In the plasma processing apparatus as described above, first, a substrate (W) as an object to be processed is loaded into the substrate processing chamber (5) and held on the susceptor (6). Next, the vacuum pump is driven to reduce the pressure through the exhaust pipe (41), and the inside of the container (11) and the substrate processing chamber (5) is reduced to, for example, 10 to 2000 mTorr. And the gas for plasma is supplied through a gas supply pipe | tube (43), maintaining the degree of vacuum in a container (11).

As the plasma gas, various material gases are used according to the process, as in the case of a conventional processing apparatus. For example, oxygen, hydrogen, argon, water, or the like is used in the ashing process, and fluorine, bromine, chlorine, or the like is used in the etching process. Then, high frequency power of 27.12 MHz, 2 KW, for example, is supplied from the high frequency power source (2) to the resonance coil (12) of the resonator (1). As a result, when the resonance coil (12) has a single wavelength, an induced electric field is generated around it, and a donut-shaped induction is generated at a middle height of the container (11) corresponding to the electrical midpoint of the resonance coil (12). Plasma is excited.

In the plasma processing apparatus as described above, the type and flow rate of the plasma gas to be supplied, the degree of vacuum of the container (11) of the resonator (1), and the high-frequency power to be applied are changed as the process is changed. As a result, the load impedance in the resonator (1) when plasma is generated differs. Incidentally, FIG. 3 shows the electrical characteristics of the resonator (1) in which the load impedance is adjusted to 50 ohms using a fixed ground, and FIG. The electrical characteristics of the resonator (1) changed to 60 ohms are shown.

On the other hand, since the helical resonance apparatus of the present invention can select the grounding position of the resonance coil (12) according to the processing conditions (process conditions), it can respond quickly. That is, in the helical resonance apparatus, the impedance in the resonator (1) fluctuates each time the processing conditions are changed. In the present invention, a plurality of resonances are provided corresponding to several preset process conditions. Since the ground terminal of the coil (12) can be selected by the switching operation of the vacuum relay (16), the load impedance on the resonator (1) side at the time of plasma generation is immediately reset to, for example, 50 ohms according to the change of process conditions. it can.

In other words, in the helical resonance apparatus of the present invention, the structure in which the grounding position can be selected in the resonance coil (12) is configured so that the load impedance of the resonator (1) is set on the high frequency power source (2) side according to the processing conditions. Can be immediately matched to the impedance. Therefore, it is not necessary to perform initial adjustment every time the processing conditions are changed, and the optimum resonance characteristics can be obtained in the resonator (1), so that high-frequency power can be supplied to the maximum. Incidentally, FIG. 5 shows the electrical characteristics of the resonator (1) in which the load impedance is reset to 50 ohms by turning on the vacuum relay according to the change of the processing conditions.

By the way, the electrical length of the resonance coil (12) in the helical resonance device is about 11 m in all wavelength modes in the case of 27.12 MHz, for example, whereas the adjustment of the load impedance of the resonator (1) is A ground terminal (fixed ground (14), vacuum relays (16, 16) set in advance at an interval of about 1 cm between the power feeding position of the resonance coil (12) and one of the ground positions is about 20 cm long. )) Is selected. Therefore, in adjusting the load impedance, it is possible to match only the impedance without substantially affecting the resonance frequency of the electrical characteristics.

However, when the grounding position of the resonance coil (12) is switched as described above, the electrical length of the resonance coil (12) changes as a result, and the resonance frequency also changes. Become. In addition, the resonance frequency is slightly increased due to the above-described capacitive coupling between the voltage portion of the resonance coil (12) and the plasma when the plasma is generated and the above-described inductive coupling variation between the container (11) and the plasma. While fluctuating. In practice, resonance occurs at a frequency slightly higher than the resonance point of the resonator (1) in the unloaded state. As a result, reflected wave power is generated at a fixed resonance frequency, and the transfer efficiency of high-frequency power is slightly reduced.

Therefore, in order to compensate for the decrease in the transfer efficiency of the high-frequency power due to the slight fluctuation of the resonance frequency as described above, in the preferred embodiment of the helical resonance device according to the present invention, as shown in FIG. Is provided with a frequency matching unit (3) for adjusting the oscillation frequency so that the reflected wave power detected by the reflected wave power meter (26) installed on the output side is minimized.

As shown in FIG. 6A, the frequency matching unit (3) is an A / D converter (31) for digitally converting a control analog signal into a frequency signal, and the value of the converted frequency signal is preset and stored. An arithmetic processing circuit (32) for calculating the oscillation frequency based on the value of the oscillation frequency, a D / A converter (33) for converting the frequency value obtained by the arithmetic processing into a voltage signal, and a D / A converter The voltage controlled oscillator (34) that oscillates in accordance with the applied voltage from (33).

Further, the frequency matching unit (3) digitally outputs the frequency value obtained by the arithmetic processing as shown in FIG. 6 (b) instead of the D / A converter (33) and the voltage controlled oscillator (34). Digital I / O (35) and a frequency generator of a direct digital synthesis system that synthesizes a digital signal according to a signal from the digital I / O (35) and generates a frequency signal based on the synthesized signal (36) may be comprised.

That is, in FIG. 6, a partial diagram (a) shows an aspect of a frequency matching unit (3) in which an analog voltage-controlled oscillator is used, and a partial diagram (b) uses a digital frequency generator. The aspect of the frequency matcher (3) is shown. Hereinafter, the sections (a) and (b) in the partial diagram in FIG.

The frequency matching unit (3) adjusts the oscillation frequency of the high frequency power source (2) so that the reflected wave power detected by the reflected wave power meter (26) installed on the output side of the high frequency power source (2) is minimized. By providing a function to adjust, it is possible to reliably compensate for a decrease in effective load power.

Specifically, a reflected wave power meter (26) as a part of the high frequency power source (2) is provided on the output side of the amplifier (24), and the reflected wave power in the transmission line (25) is detected, The voltage signal is fed back to the A / D converter (31) of the frequency matching unit (3). The frequency of the high-frequency power source (2) is increased or decreased so that the reflected wave power is minimized. Thereby, the slight mismatch of the frequency which arose in the spiral resonance apparatus (1) can be supplemented on the high frequency power supply (2) side.

In the spiral resonance apparatus, as described above, plasma is generated by supplying high-frequency power from the high-frequency power source (2). At that time, the reflected wave power meter (26) detects the reflected wave power and feeds it back to the A / D converter (31) of the frequency matcher (3). The arithmetic processing circuit (32) calculates the deviation of the resonance frequency corresponding to the reflected wave power, and outputs a corrected frequency signal so that the reflected wave power in the transmission line (25) approaches zero.

6 (a), the arithmetic processing circuit (32) outputs a voltage to the voltage controlled oscillator (34) via the D / A converter (33), and the voltage controlled oscillator (34) A frequency signal of a resonance frequency suitable for the device is applied to the amplifier (24). On the other hand, in the embodiment of FIG. 6B, the arithmetic processing circuit (32) digitally outputs to the frequency generator (36) via the digital I / O (35), and the frequency generator (36) A similar corrected frequency signal is provided to the amplifier (24).

That is, the frequency matching unit (3) responds to the deviation of the resonance state during the operation of the helical resonance device (1), in other words, a slight fluctuation of the resonance frequency, and responds quickly and accurately by signal processing. Since the high-frequency power having the frequency to be output is output to the high-frequency power source (2), the power transfer efficiency can be further maximized. Moreover, since the frequency matching unit (3) has no mechanical drive part and is not interposed in the middle of the transmission line (25), there is no power loss due to the matching unit itself. Therefore, in the helical resonance apparatus of the present invention, since the power of the actual resonance frequency is supplied, a more accurate standing wave can be formed and a stable plasma with a very low potential can be maintained.

The frequency matching unit (3) may be configured to adjust the oscillation frequency based on the phase difference between the voltage and current output from the high frequency power source (2). That is, as shown in FIG. 7, the frequency matching unit (3) has a voltage and current detected by the phase detector (7) on the transmission line (5) installed between the frequency matching unit (3) and the resonator (1). A function of adjusting the oscillation frequency of the high-frequency power source (2) is provided so that the phase difference becomes 0 °.

Specifically, a phase detector (27) is interposed on the output side of the high frequency power source (2), detects a phase difference between the voltage and current in the transmission line (25), and the voltage signal is used as a frequency matching unit. Feedback is made to the A / D converter (31) of (3). The oscillation frequency is increased or decreased so that the phase difference between the voltage and current becomes 0 °. Thereby, the frequency matching unit (3) can compensate for slight fluctuations in the resonance frequency in the resonator (1) on the high frequency power source (2) side.

That is, in the above spiral resonator, when the plasma is excited by the high frequency power, the phase detector (27) detects the phase difference between the voltage and current of the traveling wave power, and the A / of the frequency matching unit (3). Feedback is provided to the D converter (31). The arithmetic processing circuit (32) calculates the deviation of the resonance frequency corresponding to the phase deviation, and increases or decreases the predetermined frequency so that the phase difference of the traveling wave power in the transmission line (25) becomes 0 °.

As in the circuit of FIG. 6, in the embodiment of FIG. 7A, the arithmetic processing circuit (32) outputs a voltage to the voltage controlled oscillator (34) via the D / A converter (33) and is corrected. The obtained frequency signal is supplied to the amplifier (24). Similarly, in the embodiment of FIG. 7 (b), the arithmetic processing circuit (32) digitally outputs to the frequency generator (36) via the digital I / O (35), and the corrected frequency signal is supplied to the amplifier (24). ).

In other words, the frequency matching unit (3) shown in FIG. 7 does not have power loss and responds quickly by signal processing and accurately resonates at a high frequency, like the frequency matching unit of FIG. Since power is output to the power source (2), the power transfer efficiency to the resonator (1) can be maximized. As a result, in the helical resonance apparatus of the present invention, a more accurate standing wave can be formed, and a stable plasma with a very low potential can be formed.

Since the spiral resonator of the present invention can generate a plasma having a very low potential, and thus can easily control the generated plasma, dry etching including ashing, ion etching, remote plasma deposition, ion plasma It can be used for a wide range of processing techniques such as plasma chemical vapor deposition such as chemical vapor deposition. In addition to devices such as semiconductor elements, flat panel displays, and finely processed products, materials such as diamond and plastic can be processed.

Longitudinal sectional view showing an outline of a spiral resonator for plasma generation applied to a plasma processing apparatus Block diagram showing an example of means for selecting a ground position in a resonance coil Waveform diagram showing the relationship between the ground position of the resonant coil and the electrical characteristics of the resonator Waveform diagram showing the relationship between the ground position of the resonant coil and the electrical characteristics of the resonator Waveform diagram showing the relationship between the ground position of the resonant coil and the electrical characteristics of the resonator A circuit block diagram showing a configuration example of a frequency matching unit provided in a high-frequency power supply A circuit block diagram showing a configuration example of a frequency matching unit provided in a high-frequency power supply

Explanation of symbols

1: Resonator
11: Container
12: Resonant coil
13: Outer shield
14: Fixed ground
15: Movable tap (fixed ground)
41: exhaust pipe
43: Gas supply pipe
2: High frequency power supply
24: Amplifier
26: Reflected wave power meter
27: Phase detector
3: Frequency matcher
5: Substrate processing chamber
6: Susceptor
W: Substrate

Claims (3)

Resonance comprising a container configured to be depressurized and supplied with plasma gas, a resonance coil wound around the outer periphery of the container, and an outer shield disposed on the outer periphery of the resonance coil and electrically grounded And a high frequency power source for supplying high frequency power of a predetermined frequency to the resonance coil, and the electrical length of the resonance coil is an integral multiple of one wavelength or a half wavelength or a quarter wavelength at the predetermined frequency. In the spiral resonator for plasma generation set to the corresponding length,
Corresponding to some preset process conditions, a plurality of ground terminals of the resonance coil including a fixed ground are provided, and the load impedance of the resonator is matched with the impedance on the high frequency power source side during operation. A spiral resonance apparatus for plasma generation, wherein the ground terminal of the resonance coil is selected according to the process condition.
By selecting a plurality of the ground terminals of the resonance coil corresponding to some of the preset process conditions by switching operation of a vacuum relay interposed between the resonance coil and the outer shield The spiral resonance apparatus for generating plasma according to claim 1, wherein the load impedance on the resonator side at the time of plasma generation can be immediately reset according to the change of the process condition.
The process conditions are types of plasma, and various material gases used as plasma generation gas are hydrogen-containing gas in the case of ashing treatment, and halogen element-containing gas in the case of etching treatment. The spiral resonance device for plasma generation according to claim 1 or 2, wherein:

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