JP2005285564A - Plasma treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment device for applying plasma treatment on a base capable of generating plasma stably even when applying plasma treatment on the base having large area to realize uniform plasma treatment. <P>SOLUTION: A plurality of coil antennas 20 around which conductor lines radiating electromagnetic waves having substantially same length are wound in the same shape are arranged like array in different regions on an outer side of a chamber 14 for generating plasma by introducing raw material gas. High frequency electric power having the same phase is fed into the plurality of these coil antennas 20. Length of the conductor line of the coil antenna 20 is one-seventh or less of transmission wavelength when high frequency electric power is transmitted as a signal. The plurality of coil antennas 20 are arranged in an antenna storage chamber 16 provided adjacent to the chamber 14. The plurality of coil antennas 20 are separated from each other by an electrical conductive plate member 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plasma processing apparatus that performs plasma processing on a substrate using plasma. For example, the present invention relates to a CVD apparatus (Chemical Vapor Deposition), an etching apparatus, or a sputtering apparatus that forms a thin film using plasma.

Today, various substrates such as semiconductor devices, solar cells, flat panel displays, etc. are processed with high precision using film formation processing and etching processing using plasma, such as CVD, etching and sputtering. .
For example, a plasma induction type processing apparatus that induces plasma in a processing chamber (chamber) by supplying high-frequency power to a coil antenna to emit electromagnetic waves is used.
On the other hand, Si wafers processed using plasma (plasma processing) in semiconductor devices, glass substrates used for flat panel displays, and the like are steadily increasing in size. Correspondingly, the vacuum processing chamber of the processing apparatus for performing the plasma processing is also enlarged, and in this vacuum processing chamber, radicals and ions in the reactive plasma that have a large influence on the processing accuracy of the substrate are uniformly generated and the substrate is generated. There is a growing need for highly accurate plasma processing.

By the way, in the following Patent Document 1, a plasma induction type processing apparatus for generating plasma by applying high-frequency power is proposed. Specifically, a plurality of high-frequency antennas formed in a planar spiral coil shape are provided outside the processing chamber, and a matching circuit and a high-frequency power source are provided for each of these high-frequency antennas in a one-to-one correspondence (Patent Document) 1 (see FIG. 12).
Thus, in a plasma processing apparatus that performs plasma processing on a target object having a relatively large area, high-density and uniform high-frequency plasma can be excited and high-precision plasma etching can be performed.
Patent Document 2 below proposes a plasma processing apparatus having an additional coil structure in the peripheral part of the main coil part.

  However, even if these plasma processing apparatuses are used, it may be difficult to perform uniform plasma processing on a large-sized substrate, and satisfactory plasma processing is not always realized. In particular, for a substrate whose plasma processing apparatus is subject to plasma processing such as a size of 730 mm × 920 mm, such as a substrate having a side length of 700 mm or more than 1000 mm, inductively coupled plasma is stably excited to perform uniform plasma processing. There was a problem that it was difficult to realize.

JP 2002-176038 A JP-T-2001-516944

  Accordingly, in order to solve the above problems, the present invention provides a plasma processing apparatus that stably generates plasma and realizes uniform plasma processing even when performing plasma processing on a large-area substrate. The purpose is to provide.

  In order to achieve the above object, the present invention is a plasma processing apparatus for performing plasma processing on a substrate using plasma, and is provided outside a chamber for generating plasma by introducing a raw material gas, An antenna around which a conductor wire is wound, which emits electromagnetic waves that generate plasma from the raw material gas introduced into the chamber by applying high-frequency power, the conductor wire being wound in the same shape, A plasma processing apparatus comprising: a plurality of planarly arranged coil antennas in different outer regions; and a single high-frequency power source that supplies high-frequency power having the same phase to the plurality of coil antennas.

Here, the length of each conductor wire of the coil antenna is 1/7 or less with respect to the propagation wavelength when the high-frequency power propagates as a signal through the conductor wire.
The plurality of coil antennas are preferably arranged in an antenna room provided adjacent to the chamber and separated from each other by using a conductive plate member as a partition wall.
Each of the plurality of coil antennas is spirally wound in the same direction and provided in different regions.

The plasma processing apparatus further includes one matching unit connected to the high-frequency power source for matching with the impedances of the plurality of coil antennas, and distributes the high-frequency power from the matching unit to each of the coil antennas to form a tournament. Power the formula. The tournament method is a method of supplying power to each coil antenna by providing a plurality of branch points for branching a conductor wire for transmitting high-frequency power into two and sequentially branching them. With this method, the conductor wire of each coil antenna is configured with the same length.
The plasma processing apparatus is further connected to the high-frequency power source, and distributes the high-frequency power from the high-frequency power source. A matching unit that distributes high-frequency power from the high-frequency power source, and feeds the distributed high-frequency power to each coil antenna via the matching unit.

  The present invention is also a plasma processing apparatus for performing plasma processing on a substrate using plasma, and a chamber for generating plasma by introducing a raw material gas, provided outside the chamber, and applying high-frequency power. An antenna that radiates an electromagnetic wave that generates plasma from the source gas introduced into the chamber and is wound with a conductor wire, and the conductor wire is wound in the same shape and is flattened in different regions outside the chamber. A plurality of coil antennas, and one power supply device that feeds the plurality of coil antennas with high-frequency power having the same phase, and the power supply device includes one oscillator that generates a high-frequency signal. , A distributor that distributes the high-frequency signal generated by the oscillator, a variable attenuator that separately controls the power of the distributed high-frequency signal, An amplifier for separately amplifying each controlled high-frequency signal, and a matching unit for matching with the impedance of each of the coil antennas. A plasma processing apparatus is provided in which power is supplied to a coil antenna in the same phase.

  Such a plasma processing apparatus can be suitably used for a dry etching apparatus or a CVD apparatus.

In order to generate plasma, the plasma processing apparatus of the present invention has a plurality of coil antennas in which conductor wires are wound in the same shape and are arranged in different regions outside the chamber. High frequency power is supplied in the same phase from a high frequency power supply or a power supply device. Thereby, the electric current which flows into a coil antenna makes electrical mirror image relation, and can align the phase of the electromagnetic waves radiated | emitted from each coil antenna. Further, by supplying the same high frequency power to the coil antenna, interference between the coil antennas is eliminated. Thereby, plasma can be generated stably and uniformly. The plasma processing apparatus of the present invention distributes high-frequency power using a single high-frequency power supply or power supply device, unlike a power supply method that independently supplies high-frequency power to a plurality of coil antennas as in Patent Document 1. In this distribution system, power is supplied to a plurality of coil antennas in the same phase. For this reason, since only one high frequency power supply or power supply device is required, the cost can be suppressed.
Further, the length of the conductor wire of the coil antenna is set to 1/7 or less of the propagation wavelength when high-frequency power propagates as a signal through the conductor wire. For this reason, the coil antenna functions as a lumped constant circuit in feeding high-frequency power, and does not generate a current distribution in which the current varies depending on the location of the conductor wire. For this reason, the coil antenna radiates electromagnetic waves of uniform strength. In particular, it can be effectively used in an apparatus for performing plasma treatment on a large-area substrate such as a liquid crystal substrate (size: 730 mm × 920 mm or more).
In addition, by providing a conductive plate material as a partition wall that separates the plurality of coil antennas on the surface that forms the electrical mirror image relationship described above, the electromagnetic waves radiated from the coil antennas can be further prevented from interfering with each other, and the same in an impedance-matched state. A high-frequency phase can be supplied.

  Hereinafter, the plasma processing apparatus of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 is a schematic configuration diagram of an inductively coupled plasma processing apparatus (hereinafter referred to as an apparatus) 10 which is an embodiment of the plasma processing apparatus of the present invention. The apparatus 10 is a processing apparatus suitably used for a large-area substrate having a substrate size of 730 mm × 920 mm or more.
The apparatus 10 has a rectangular processing container 12 made of aluminum or stainless steel, and the processing container 12 is provided with a plasma processing chamber (chamber) 14 and an antenna storage chamber 16.

The storage container 12 is provided with a quartz glass plate 18, and the chamber 14 and the antenna storage chamber 16 are separated by the quartz glass plate 18. In the antenna storage chamber 16, nine coil antennas 20 (3 × 3) are provided outside the chamber 14 in the form of an array in which conductor wires are drawn from the wall surface of the storage container 12 and wound in the same direction. (See FIG. 2). The conductor wires of the coil antennas 20 have substantially the same length and the same spiral shape. The coil antennas 20 provided in the respective antenna storage chambers 16 are arranged in different areas, and are separated from each other with the conductive plate 22 as a partition.
The reason why the coil antennas 20 are separated by using the conductive plate material 22 is to prevent interference between electromagnetic waves radiated from the coil antennas 20 adjacent to each other, and to prevent the load characteristics of the antenna from being affected, as will be described later. Because. Thereby, the radiation intensity of the electromagnetic wave from each coil antenna 20 can be made uniform. For example, a metal plate made of a non-magnetic material is used as the conductive plate material 22.

  The conductive plate 22 that partitions the antenna storage chamber 16 for each coil antenna 20 is integrated with a frame 19 provided with a metal reinforcing beam made of a non-magnetic material to support the quartz glass plate 18. The quartz glass plate 18 is mounted on the frame body 19 as a dielectric window material and is disposed at a predetermined position in the chamber 14. The frame 19 has a strength that resists the pressure that the quartz glass plate 18 and the like receives from the atmospheric pressure due to the reduced pressure of the chamber 14. In particular, in a plasma processing apparatus for processing a substrate having a large area, it is important to firmly support the quartz glass plate 18 that is wide according to the area of the chamber 14 so as not to be damaged due to the atmospheric pressure.

  Each conductor wire of the coil antenna 20 is connected to a matching box (matching unit) 25 provided on the outer side of the storage container 12 in a one-to-one correspondence with the coil antenna 20. The matching box 22 is connected to a high frequency power supply 24 that supplies high frequency power to the coil antenna 20 via a distributor 26. That is, the high frequency power generated by the high frequency power supply 24 is distributed to the nine matching boxes 25 via the distributor 26 and is supplied to each coil antenna 20.

  Although not shown, the high-frequency power source 24 combines, for example, one oscillator, a distributor that distributes the oscillated low-power signal, an amplifier that amplifies each distributed low-power signal, and the amplified signal. And a coupler.

Further, the storage container 12 is provided with a gas inlet 28 for introducing a source gas for generating plasma, and is connected to a source gas supply source 30.
On the other hand, a lower electrode 34 that also serves as a mounting table on which a substrate 32 to be plasma-processed is placed is provided below the storage container 12, and is connected to a high-frequency power source 36 provided outside the storage container 12. Further, an exhaust port 38 for maintaining the decompressed state in the chamber 14 is provided at the lower portion of the storage container 12 and is connected to a vacuum pump (not shown).

FIG. 2 is a diagram schematically showing the arrangement of the coil antenna 20 of the device 10. In FIG. 2, the conductive plate member 22 is omitted.
In the apparatus 10, the conductor wires of nine coil antennas 20 are spirally wound to form a rectangular shape and arranged in an array above the quartz glass 18. In these coil antennas 20, the conductor wires are formed in the same shape so as to have the same radiation characteristics, and the length of the conductor wires is 1/7 of the propagation wavelength of the signal of the high frequency power. It is as follows.
That is, as shown in FIG. 3, the total length L of the conductor wire extending from the matching box 25 and returning to the matching box 25 of one coil antenna 20 is 1/7 or less of the propagation wavelength λ of the signal of the high frequency power. ing. Thus, the length of the conductor wire of the coil antenna 20 is limited.

  For example, when the coil antenna 20 is fed with a high frequency of 13.56 MHz, the coil antenna 20 functions as a distributed constant circuit, and a current distribution is generated depending on the location of the conductor wire. This is for avoiding the distribution of the intensity of the radiated electromagnetic wave. For this reason, the coil antenna 20 is caused to function as a lumped constant circuit by setting it to 1/7 or less of the propagation wavelength λ of the signal of the high frequency power, and the current that affects the radiation of the electromagnetic wave changes depending on the location of the conductor line L Things will disappear. In particular, since the uniform current distribution can be ensured over the entire length L of the coil antenna by setting it to 1/10 or less of the propagation wavelength λ of the signal of the high frequency power, it is more preferable that the propagation wavelength λ is 10 minutes. 1 or less.

  For example, when high frequency power (13.56 MHz) having a propagation wavelength λ of 22.12 m is supplied to a coil antenna having a total length L of the conductor wire of 3.2 m, that is, the length of the coil antenna (the total length L of the conductor wire) is If the propagation wavelength λ is 1/7 (= 3.2 / 22.12), the coil antenna 20 functions as a lumped constant circuit, and the current that affects the radiation of electromagnetic waves does not change depending on the location of the conductor wire. It has been confirmed that it emits uniform electromagnetic waves. Therefore, the total length L of the coil antenna 20 needs to be at least 1/7 or less. In particular, when plasma processing is performed on a substrate having a large area exceeding 1000 mm × 1000 mm, it is important to limit the length of the conductor wire of the coil antenna 20 because the coil antenna needs to function as a lumped constant circuit. Since the length of the conductor wire of the coil antenna 20 is limited, the number of coil antennas 20 arranged in an array increases.

  On the other hand, the conductive plate 22 is a partition material that functions so that electromagnetic waves generated by adjacent coil antennas 20 do not interfere with each other as shown in FIG. When an electromagnetic wave generated by one of the adjacent coil antennas 20 acts on the adjacent coil antenna 20, the reactance component of the coil antenna 20 changes and the load characteristics of the coil antenna 20 change. Thereby, impedance matching collapses. As a result, the feeding of high-frequency power is affected, and the generation of electromagnetic waves is non-uniform for each coil antenna. The conductive plate 22 prevents such a state from occurring. In particular, the currents flowing through adjacent coil antennas 20 having the same shape have a mirror image relationship, and the radiation form of the radiated electromagnetic waves has a mirror image relationship. For this reason, even if the electroconductive board | plate material 22 is provided on the boundary line (center line) of the adjacent coil antenna 20, the radiation distribution of electromagnetic waves is not disturbed. For this reason, even if the radiation intensity changes between the coil antennas 20 and becomes unbalanced, or the radiation phase is slightly shifted, interference of electromagnetic waves between the coil antennas 20 can be effectively suppressed.

In the device 10, interference of electromagnetic waves between the coil antennas 20 is suppressed by providing the conductive plate 22. However, in the present invention, the conductive plate 22 is not necessarily provided as long as high-frequency power is fed in the same phase. It does not have to be provided.
As shown in FIG. 5 (a), electromagnetic waves do not interfere with each other by supplying high-frequency power in the same phase in order to make the radiant intensity of electromagnetic waves generated by adjacent coil antennas 20 substantially equal. , Electromagnetic waves are not emitted unevenly. When electromagnetic waves are generated in opposite phases as shown in FIG. 5B, the electromagnetic waves easily interfere with each other to change the load characteristics of the coil antenna. For this reason, impedance matching cannot be achieved and the generated plasma becomes unstable. For this reason, it is necessary to supply high-frequency power to the coil antenna 20 in the same phase, and it is not always necessary to provide the conductive plate 22 as long as this is the case. However, it is preferable to provide the conductive plate 22 from the viewpoint of effectively and stably suppressing interference of electromagnetic waves.

In the apparatus 10, as shown in FIG. 2, the high frequency power generated by one high frequency power supply 24 is distributed by the distributor 26 and the high frequency power is supplied to the coil antenna 20 in the same phase. In this case, the matching unit 24 performs impedance matching by the matching box 25 according to the load characteristics of the coil antenna 20.
The coil antenna 20 has the same conductor wire length, has a spiral shape of the same size, and further includes a conductive plate member 22 so that electromagnetic waves do not interfere with each other. It can be aligned with the phase.
In the present embodiment, the high frequency power can be supplied to the plurality of coil antennas by using one high frequency power source and a distributor because the high frequency power is supplied to the coil antennas in the same phase.

  In the above embodiment, one high-frequency power source 24, a distributor 26 that is connected to the high-frequency power source 24 and distributes high-frequency power from the high-frequency power source 24, and a matching box 25 provided corresponding to each of the coil antennas 20 The high frequency power from the high frequency power supply 24 is distributed, and the distributed high frequency power is supplied to each coil antenna 20 via the matching box 25. Thereby, electromagnetic waves can be radiated from the coil antenna 20 in the same phase.

  In such a plasma processing apparatus, for example, a process processing apparatus that performs a process on a substrate having a size of 730 mm × 920 mm, four coil antennas are provided in an array, and the total length L of one coil antenna is 1.9 m, for example, 13 The propagation wavelength λ (22.12 m) of a high frequency signal of .56 MHz can be set to 1/7 or less. In a process processing apparatus for processing a substrate having a size of 2000 mm × 2000 mm, nine coil antennas are provided in an array (3 × 3), the total length L of the coil antenna is 3.1 m, and a high frequency of, for example, 13.56 MHz. 1/7 or less of the wavelength λ (22.12 m) of the propagation signal. Thus, the number of coil antennas arranged in an array fed with the same phase is determined according to the length of the coil antenna determined by the frequency of the high frequency power to be used.

In the plasma processing apparatus 10 of this embodiment, a matching box 25 is provided corresponding to each of the coil antennas 20 arranged in an array, and each coil antenna 20 is routed from one high-frequency power supply 24 via each matching box 25. However, the power supply method of the present invention is not limited to this.
FIG. 6 is a diagram illustrating an example of another power feeding method for feeding power to the coil antenna. 6 is a system in which power is supplied to each coil antenna 20 in a tournament format via one matching box 25 connected to one high-frequency power supply 24. The tournament method is a method of supplying power to each coil antenna by providing a plurality of branch points for branching a conductor wire for transmitting high-frequency power into two and sequentially branching them. This method enables compact conductor wiring. In this case, the total length L of the conductor wire extending from the matching box 25 and returning to the matching box 25 via each coil antenna 20 (in FIG. 6, point A to point B, point A to point C, point A to point D, The lengths of the conductor lines from point A to point E) are the same, and are equal to or less than one-seventh of the propagation wavelength λ of the high-frequency power signal. As a result, the coil antenna 20 can function as a lumped constant circuit, and uniform plasma can be generated. Note that the embodiment shown in FIG. 6 is an example in which four coil antennas 20 are provided.

The plasma processing apparatus of the present invention can also be configured using a power supply apparatus as shown in FIG.
FIG. 7 is a diagram showing a circuit configuration for supplying power to the coil antenna 66 in the same phase.
The power supply device 50 that supplies power to the coil antenna 66 includes one oscillator 54 that generates a high-frequency signal of about 10 W or less, a distributor 56 that distributes the high-frequency signal generated by the oscillator 54, and the power of the distributed high-frequency signal. The variable attenuator 58 that controls the power separately, the amplifier 60 that amplifies each high-frequency signal whose power is controlled separately, and the matching box 62 that matches the impedance of the coil antenna 66. The power supply device 50 supplies the amplified high frequency signal to each coil antenna 66 via the matching box 62 as high frequency power.

  The matching box 62 is provided with a current / voltage detection sensor 64 that detects the current and voltage of the high-frequency power to be fed, and a controller (not shown) that controls the variable attenuator 58 according to the detected current and voltage. ing. This controller controls the value of electric power applied to each coil antenna 66 so that each coil antenna 66 radiates electromagnetic waves with substantially the same radiation intensity. In addition, the controller adjusts the reactance element in the matching box 62 in accordance with the detected current and voltage for impedance matching in the matching box 62.

  With such a configuration, the amplifier 60 and the matching box 62 can be provided close to each other, and it is not necessary to use a dedicated transmission cable for transmitting high-frequency power. For this reason, transmission loss due to the transmission cable is eliminated. Furthermore, it is not necessary to match the output impedance (several Ω) of the amplifier 60 with the impedance 50Ω of the transmission cable, and an impedance converter is not required. For this reason, the power loss due to the impedance converter is eliminated.

The voltage of the output signal (high frequency signal) from the amplifier 60 is adjusted by the control of the variable attenuator 58. This adjustment is performed based on the current and voltage detection results detected by the current / voltage detection sensor 64 provided in the matching box 62. Further, impedance matching in the matching box 62 is performed based on the detection results of the current and voltage. As a result, electromagnetic waves are radiated from the coil antenna 66 in a state of impedance matching and in the same phase to generate plasma.
Thus, in this embodiment, the high frequency power can be supplied to the plurality of coil antennas using one oscillator and a distributor because the high frequency power is supplied to the coil antennas in the same phase.

  The plasma processing apparatus of the present invention has been described in detail above. However, the present invention is not limited to the above embodiment, and various modifications and changes may be made without departing from the spirit of the present invention. is there.

It is a schematic block diagram of the inductively coupled plasma processing apparatus which is one Embodiment of the plasma processing apparatus of this invention. It is the figure which represented typically arrangement | positioning of the coil antenna of the apparatus shown in FIG. It is a figure explaining the length of the conductor wire of the coil antenna in the plasma processing apparatus of this invention. It is a figure explaining the electroconductive board | plate material used as a partition of the coil antenna in the plasma processing apparatus of this invention. (A) And (b) is a figure explaining the mutual interference of the electromagnetic waves radiated | emitted with a coil antenna. It is a figure explaining the other electric power feeding system electrically fed to the coil antenna in the plasma processing apparatus of this invention. It is a figure which shows the other electric power feeding circuit structure of the coil antenna of the inductively coupled plasma processing apparatus which is one Embodiment of the plasma processing apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inductively coupled plasma processing apparatus 12 Processing container 14 Plasma processing chamber (chamber)
16 Antenna storage chamber 18 Quartz glass plate 20, 66 Coil antenna 24, 36 High frequency power supply 25, 62 Matching box 26 Distributor 28 Gas inlet 30 Raw material gas supply source 32 Substrate 34 Lower electrode 38 Exhaust port 50 Power supply device 54 Oscillator 56 Distributor 58 Variable attenuator 60 Amplifier 64 Current / voltage detection sensor

Claims (7)

A plasma processing apparatus for performing plasma processing on a substrate using plasma,
A chamber for introducing a source gas to generate plasma;
An antenna that is provided outside the chamber and that emits electromagnetic waves that generate plasma from the source gas introduced into the chamber by applying high-frequency power, and is wound around a conductor wire, the conductor wire having the same shape A plurality of coil antennas wound around and disposed in different areas outside the chamber;
A plasma processing apparatus, comprising: one high frequency power source that supplies high frequency power having the same phase to the plurality of coil antennas.   The plasma processing apparatus according to claim 1, wherein the length of each conductor wire of the coil antenna is 1/7 or less with respect to a propagation wavelength when the high-frequency power propagates as a signal through the conductor wire.   3. The plasma processing apparatus according to claim 1, wherein the plurality of coil antennas are arranged in an antenna room provided adjacent to the chamber and separated from each other by using a conductive plate member as a partition wall.   The plasma processing apparatus according to claim 1, wherein each of the plurality of coil antennas is spirally wound in the same direction and provided in different regions. And further comprising one matching unit connected to the high-frequency power source to match the impedance of the plurality of coil antennas,
The plasma processing apparatus according to claim 4, wherein high-frequency power is distributed from the matching unit to each of the coil antennas and is fed in a tournament manner. Furthermore, a distributor that is connected to the high-frequency power source and distributes high-frequency power from the high-frequency power source, and a matching unit that is provided corresponding to each of the coil antennas and that matches each impedance of the coil antenna, Prepared,
The plasma processing apparatus of Claim 4 which distributes the high frequency electric power from the said high frequency power supply, and supplies the distributed high frequency electric power to each coil antenna via the said matching device. A plasma processing apparatus for performing plasma processing on a substrate using plasma,
A chamber for introducing a source gas to generate plasma;
An antenna that is provided outside the chamber and that emits electromagnetic waves that generate plasma from the source gas introduced into the chamber by applying high-frequency power, and is wound around a conductor wire, the conductor wire having the same shape A plurality of coil antennas wound around and disposed in different areas outside the chamber;
A power supply device that feeds the plurality of coil antennas with high-frequency power having the same phase, and
This power supply device includes one oscillator that generates a high-frequency signal, a distributor that distributes the high-frequency signal generated by the oscillator, a variable attenuator that separately controls the power of the distributed high-frequency signal, An amplifier that amplifies each controlled high-frequency signal separately, and a matching unit that matches the impedance of each of the coil antennas, and the amplified high-frequency signal as high-frequency power via the matching unit, A plasma processing apparatus, wherein the coil antenna is fed in the same phase.

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