WO2013118520A1 - Plasma treatment method and plasma treatment device - Google Patents

Plasma treatment method and plasma treatment device Download PDF

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Publication number
WO2013118520A1
WO2013118520A1 PCT/JP2013/050055 JP2013050055W WO2013118520A1 WO 2013118520 A1 WO2013118520 A1 WO 2013118520A1 JP 2013050055 W JP2013050055 W JP 2013050055W WO 2013118520 A1 WO2013118520 A1 WO 2013118520A1
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Prior art keywords
plasma
microwave
microwaves
processed
processing
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PCT/JP2013/050055
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French (fr)
Japanese (ja)
Inventor
俊彦 塩澤
準弥 宮原
藤野　豊
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東京エレクトロン株式会社
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Priority to KR1020147025025A priority Critical patent/KR101681061B1/en
Publication of WO2013118520A1 publication Critical patent/WO2013118520A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
    • H01J37/32192—Microwave generated discharge
    • H01J37/32201—Generating means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
    • H01J37/32192—Microwave generated discharge
    • H01J37/32211—Means for coupling power to the plasma
    • H01J37/32238—Windows
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
    • H01J37/32192—Microwave generated discharge
    • H01J37/32266—Means for controlling power transmitted to the plasma
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
    • H01J37/32192—Microwave generated discharge
    • H01J37/32311—Circuits specially adapted for controlling the microwave discharge
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
    • H01L21/02112—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer
    • H01L21/02123—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon
    • H01L21/02164—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon the material being a silicon oxide, e.g. SiO2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
    • H01L21/02112—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer
    • H01L21/02123—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon
    • H01L21/0217—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
    • H01L21/02227—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process
    • H01L21/0223—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate
    • H01L21/02233—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer
    • H01L21/02236—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer group IV semiconductor
    • H01L21/02238—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer group IV semiconductor silicon in uncombined form, i.e. pure silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
    • H01L21/02227—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process
    • H01L21/02247—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by nitridation, e.g. nitridation of the substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
    • H01L21/02227—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process
    • H01L21/02252—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by plasma treatment, e.g. plasma oxidation of the substrate
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/46—Generating plasma using applied electromagnetic fields, e.g. high frequency or microwave energy
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/46—Generating plasma using applied electromagnetic fields, e.g. high frequency or microwave energy
    • H05H1/461—Microwave discharges
    • H05H1/463—Microwave discharges using antennas or applicators

Definitions

  • the present invention relates to a plasma processing method for forming a thin film such as a silicon oxide film (SiO 2 film) and a silicon nitride film (SiN film) on an object to be processed using plasma, and a plasma processing apparatus used therefor.
  • a plasma processing method for forming a thin film such as a silicon oxide film (SiO 2 film) and a silicon nitride film (SiN film) on an object to be processed using plasma, and a plasma processing apparatus used therefor.
  • a film forming process such as an oxidation process or a nitriding process is performed on an object to be processed using plasma.
  • a film forming process such as an oxidation process or a nitriding process is performed on an object to be processed using plasma.
  • Patent Document 1 International Publication WO2002 / 058130 discloses a slot antenna that generates plasma by introducing a microwave into a processing container using a planar antenna having a plurality of slots.
  • a technique for forming a silicon oxide film using a plasma processing apparatus of the type has been proposed.
  • Patent Document 1 In the plasma processing method described in Patent Document 1, it is considered that a thin silicon oxide film of about 1.6 nm can be formed. However, in future device development, it is expected to form a thin film with a thinner film thickness.
  • the plasma processing method of the present invention is a method of forming a thin film on the surface of the object to be processed using a plasma processing apparatus for processing the object to be processed by generating plasma in a processing container using a plurality of microwaves.
  • the total power of microwaves when the plasma is ignited by the plurality of microwaves is 1 W / cm 2 or less per area of the object to be processed, and the film thickness of the thin film is It may be 1 nm or less.
  • the diameter of the object to be processed is 300 mm or more, the total power of microwaves when the plasma is ignited by the plurality of microwaves is 700 W or less, and the thin film The film thickness may be 1 nm or less.
  • the processing temperature for processing the object to be processed by the plasma is 100 ° C. or less.
  • the thin film may be a silicon oxide film in which silicon on the surface of the object to be processed is oxidized, or silicon nitride in which silicon on the surface of the object to be processed is nitrided It may be a membrane.
  • the plasma processing apparatus includes the processing container that houses the object to be processed, and a mounting surface that is disposed inside the processing container and mounts the object to be processed. You may provide the mounting base and the gas supply mechanism which supplies process gas in the said process container.
  • the plasma processing apparatus generates the microwave, distributes the microwave to a plurality of paths, and outputs the microwave, and outputs the microwave from the microwave output unit.
  • a plurality of antenna portions for introducing the plurality of microwaves into the processing container, and impedance between the microwave output portion and the processing container provided corresponding to the plurality of antenna portions, respectively. And a plurality of tuners to be matched.
  • the plasma processing apparatus is disposed in an upper part of the processing container, and is fitted into the conductive member having a plurality of openings and the plurality of openings, And a plurality of microwave transmission windows through which the microwave is transmitted.
  • the plasma may be generated by the plurality of microwaves introduced into the processing container from the plurality of microwave transmission windows.
  • the total power of the microwaves when the plasma is ignited by the plurality of microwaves is the total power of the microwaves when the object to be processed is processed by the plasma. May be larger.
  • the impedance matching may not be performed when the plasma is ignited by the plurality of microwaves, and the impedance matching may be performed when the object to be processed is processed by the plasma.
  • the plasma processing method of the present invention includes a step of igniting the plasma by supplying the plurality of microwaves from the microwave output unit with a first power for igniting the plasma, and a power of the microwave. May be changed to a second power lower than the first power, and the impedance matching may be performed in the state of the second power.
  • the plurality of microwave transmission windows surround one central microwave transmission window disposed in a central portion of the conductive member, and the central microwave transmission window, You may have the at least 6 outer side microwave transmission window arrange
  • the plasma processing apparatus of the present invention is a plasma processing apparatus that forms a thin film on the surface of an object to be processed by generating plasma in a processing container using a plurality of microwaves.
  • the plasma processing apparatus includes a processing container that accommodates an object to be processed, a mounting table that is disposed inside the processing container and has a mounting surface on which the object to be processed is mounted, and a processing gas that flows into the processing container. And a gas supply mechanism for supplying.
  • the plasma processing apparatus of the present invention generates a microwave, distributes the microwave to a plurality of paths, and outputs the microwave, and a plurality of microwaves output from the microwave output unit A plurality of antenna portions for introducing a plurality of antennas into the processing vessel, and a plurality of tuners provided corresponding to the plurality of antenna portions to match impedances between the microwave output portion and the processing vessel, respectively. It is equipped with. Furthermore, the plasma processing apparatus of the present invention is disposed at the upper portion of the processing container, and is fitted with the conductive member having a plurality of openings and the plurality of openings, and transmits the microwave into the processing container. And a plurality of microwave transmission windows to be introduced.
  • the total power of the microwaves when the plasma is ignited by the plurality of microwaves in the processing container is 1 W / cm 2 or less per area of the object to be processed.
  • a control unit is provided for controlling the film thickness of the thin film to 1 nm or less by introducing microwaves into the processing container from the plurality of microwave transmission windows.
  • a thin film having a thickness of, for example, 1 nm or less can be formed on the surface of an object to be processed with good controllability.
  • FIG. 1 It is sectional drawing which shows the schematic structure of the plasma processing apparatus used by embodiment of this invention. It is explanatory drawing which shows the structure of the control part shown in FIG. It is explanatory drawing which shows the structure of the microwave introduction apparatus shown in FIG. It is sectional drawing which shows the microwave introduction mechanism shown in FIG. It is a perspective view which shows the antenna part of the microwave introduction mechanism shown in FIG. It is a top view which shows the planar antenna of the microwave introduction mechanism shown in FIG. It is a bottom view of the ceiling part of the processing container shown in FIG. It is explanatory drawing which shows arrangement
  • 2 is a Paschen curve representing the relationship between pressure and ignition power in the plasma processing apparatus shown in FIG. It is a characteristic view which shows the relationship between the film thickness of a silicon oxide film at the time of performing plasma oxidation processing at different processing temperature, and processing time. It is a characteristic view which shows the relationship between the procedure of impedance matching at the time of igniting oxygen plasma with the plasma processing apparatus shown in FIG. 1, and plasma light emission. It is a characteristic view which shows the relationship between another procedure of impedance matching at the time of igniting oxygen plasma with the plasma processing apparatus shown in FIG. 1, and plasma light emission. It is a timing chart which shows the procedure of the impedance matching at the time of igniting oxygen plasma with the plasma processing apparatus shown in FIG.
  • FIG. 1 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus used in the present embodiment.
  • FIG. 2 is an explanatory diagram illustrating a configuration of the control unit illustrated in FIG. 1.
  • the plasma processing apparatus 1 used in the present embodiment involves, for example, plasma oxidation processing and plasma processing on a semiconductor wafer (hereinafter simply referred to as “wafer”) W for manufacturing semiconductor devices, with a plurality of continuous operations.
  • wafer semiconductor wafer
  • This is an apparatus for performing a film forming process such as a nitriding process.
  • the plasma processing apparatus 1 includes a processing container 2 that accommodates a wafer W that is an object to be processed, a mounting table 21 that is disposed inside the processing container 2 and has a mounting surface 21 a on which the wafer W is mounted, and a processing container 2.
  • a gas supply mechanism 3 for supplying gas therein and an exhaust device 4 for evacuating the inside of the processing container 2 under reduced pressure are provided.
  • the plasma processing apparatus 1 generates a microwave for generating plasma in the processing container 2 and introduces a microwave into the processing container 2, and each of the plasma processing apparatuses 1.
  • a control unit 8 for controlling the components.
  • an external gas supply mechanism that is not included in the configuration of the plasma processing apparatus 1 may be used instead of the gas supply mechanism 3.
  • the processing container 2 has a substantially cylindrical shape, for example.
  • the processing container 2 is made of a metal material such as aluminum and an alloy thereof.
  • the microwave introduction device 5 is provided in the upper part of the processing container 2 and functions as a plasma generating unit that introduces electromagnetic waves (microwaves) into the processing container 2 to generate plasma.
  • the configuration of the microwave introduction device 5 will be described in detail later.
  • the processing container 2 has a plate-like ceiling part 11 and a bottom part 13, and a side wall part 12 that connects the ceiling part 11 and the bottom part 13.
  • the ceiling part 11 has a plurality of openings.
  • the side wall portion 12 has a loading / unloading port 12 a for loading / unloading the wafer W to / from a transfer chamber (not shown) adjacent to the processing container 2.
  • a gate valve G is disposed between the processing container 2 and a transfer chamber (not shown).
  • the gate valve G has a function of opening and closing the loading / unloading port 12a.
  • the gate valve G hermetically seals the processing container 2 in the closed state, and enables the transfer of the wafer W between the processing container 2 and a transfer chamber (not shown) in the open state.
  • the bottom 13 has a plurality (two in FIG. 1) of exhaust ports 13a.
  • the plasma processing apparatus 1 further includes an exhaust pipe 14 that connects the exhaust port 13 a and the exhaust apparatus 4.
  • the exhaust device 4 includes an APC valve and a high-speed vacuum pump that can depressurize the internal space of the processing vessel 2 to a predetermined vacuum level at high speed. Examples of such a high-speed vacuum pump include a turbo molecular pump. By operating the high-speed vacuum pump of the exhaust device 4, the internal space of the processing container 2 is depressurized to a predetermined degree of vacuum, for example, 0.133 Pa.
  • the plasma processing apparatus 1 further includes a support member 22 that supports the mounting table 21 in the processing container 2 and an insulating member 23 made of an insulating material provided between the support member 22 and the bottom portion 13 of the processing container 2.
  • the mounting table 21 is used for horizontally mounting the wafer W, which is an object to be processed.
  • the support member 22 has a cylindrical shape extending from the center of the bottom portion 13 toward the internal space of the processing container 2.
  • the mounting table 21 and the support member 22 are made of, for example, AlN.
  • the plasma processing apparatus 1 further includes a high frequency bias power source 25 that supplies high frequency power to the mounting table 21 and a matching unit 24 provided between the mounting table 21 and the high frequency bias power source 25.
  • the high frequency bias power supply 25 supplies high frequency power to the mounting table 21 in order to attract ions to the wafer W.
  • the plasma processing apparatus 1 further includes a temperature control mechanism for heating or cooling the mounting table 21.
  • the temperature control mechanism controls the temperature of the wafer W within a range of 25 ° C. (room temperature) to 900 ° C.
  • the mounting table 21 has a plurality of support pins provided so as to be able to project and retract with respect to the mounting surface 21a.
  • the plurality of support pins are configured to be displaced up and down by an arbitrary lifting mechanism so that the wafer W can be transferred to and from a transfer chamber (not shown) at the raised position.
  • the plasma processing apparatus 1 further includes a gas introduction part 15 provided in the ceiling part 11 of the processing container 2.
  • the gas introduction part 15 has a plurality of nozzles 16 having a cylindrical shape.
  • the nozzle 16 has a gas hole 16a formed on the lower surface thereof. The arrangement of the nozzles 16 will be described later.
  • the gas supply mechanism 3 includes a gas supply device 3 a including a gas supply source 31, and a pipe 32 that connects the gas supply source 31 and the gas introduction unit 15.
  • a gas supply device 3 a including a gas supply source 31, and a pipe 32 that connects the gas supply source 31 and the gas introduction unit 15.
  • one gas supply source 31 is illustrated, but the gas supply device 3 a may include a plurality of gas supply sources according to the type of gas used.
  • the gas supply source 31 is used as a gas supply source of, for example, a rare gas for plasma generation or a processing gas used for oxidation treatment or nitridation treatment.
  • a rare gas for plasma generation or a processing gas used for oxidation treatment or nitridation treatment for example, Ar, Kr, Xe, He, or the like is used as a rare gas for generating plasma.
  • an oxidizing gas such as oxygen gas or ozone gas is used.
  • the processing gas used for the nitriding treatment for example, nitrogen gas, NH 3 gas or the like is used.
  • the rare gas may be used together with a processing gas for oxidation treatment or a processing gas for nitridation treatment.
  • the gas supply device 3a further includes a mass flow controller and an opening / closing valve provided in the middle of the pipe 32.
  • the types of gases supplied into the processing container 2 and the flow rates of these gases are controlled by a mass flow controller and an opening / closing valve.
  • the control unit 8 is typically a computer.
  • the control unit 8 includes a process controller 81 including a CPU, and a user interface 82 and a storage unit 83 connected to the process controller 81.
  • the process controller 81 is a component related to process conditions such as temperature, pressure, gas flow rate, high frequency power for bias application, microwave output, and the like (for example, high frequency bias power supply 25, gas supply device). 3a, the exhaust device 4, the microwave introduction device 5 and the like).
  • the user interface 82 includes a keyboard and a touch panel on which a process manager manages command input in order to manage the plasma processing apparatus 1, a display that visualizes and displays the operating status of the plasma processing apparatus 1, and the like.
  • the storage unit 83 stores a control program (software) for realizing various processes executed by the plasma processing apparatus 1 under the control of the process controller 81, a recipe in which processing condition data, and the like are recorded. .
  • the process controller 81 calls and executes an arbitrary control program or recipe from the storage unit 83 as necessary, such as an instruction from the user interface 82. Thus, a desired process is performed in the processing container 2 of the plasma processing apparatus 1 under the control of the process controller 81.
  • control program and recipe described above can be stored in a computer-readable storage medium such as a CD-ROM, hard disk, flexible disk, flash memory, DVD, or Blu-ray disk. Also, the above recipe can be transmitted from other devices as needed via, for example, a dedicated line and used online.
  • FIG. 3 is an explanatory diagram showing the configuration of the microwave introduction device 5.
  • FIG. 4 is a cross-sectional view showing the microwave introduction mechanism shown in FIG.
  • FIG. 5 is a perspective view showing an antenna portion of the microwave introduction mechanism shown in FIG.
  • FIG. 6 is a plan view showing a planar antenna of the microwave introduction mechanism shown in FIG.
  • the microwave introduction device 5 is provided on the upper portion of the processing container 2 and functions as a plasma generating means for introducing an electromagnetic wave (microwave) into the processing container 2 to generate plasma.
  • the microwave introduction device 5 is disposed on the upper portion of the processing container 2 and generates a microwave, and a ceiling portion 11 that is a conductive member having a plurality of openings, A microwave output unit 50 that distributes and outputs the microwaves to a plurality of paths, and an antenna unit 60 that introduces the microwaves output from the microwave output unit 50 into the processing container 2 are provided.
  • the ceiling portion 11 of the processing container 2 also serves as the conductive member of the microwave introduction device 5.
  • the microwave output unit 50 distributes the microwave amplified by the power supply unit 51, the microwave oscillator 52, the amplifier 53 that amplifies the microwave oscillated by the microwave oscillator 52, and the microwave amplified by the amplifier 53 to a plurality of paths. And a distributor 54.
  • the microwave oscillator 52 oscillates microwaves (for example, PLL oscillation) at a predetermined frequency (for example, 860 MHz).
  • the microwave frequency is not limited to 860 MHz, and may be 2.45 GHz, 8.35 GHz, 5.8 GHz, 1.98 GHz, or the like.
  • the distributor 54 distributes the microwave while matching the impedances of the input side and the output side.
  • the antenna unit 60 includes a plurality of antenna modules 61.
  • Each of the plurality of antenna modules 61 introduces the microwave distributed by the distributor 54 into the processing container 2.
  • the configurations of the plurality of antenna modules 61 are all the same.
  • Each antenna module 61 includes an amplifier unit 62 that mainly amplifies and outputs the distributed microwave, and a microwave introduction mechanism 63 that introduces the microwave output from the amplifier unit 62 into the processing container 2. ing.
  • the amplifier unit 62 includes a phase shifter 62A that changes the phase of the microwave, a variable gain amplifier 62B that adjusts the power level of the microwave input to the main amplifier 62C, a main amplifier 62C configured as a solid state amplifier, It includes an isolator 62D that separates reflected microwaves that are reflected by an antenna portion of a microwave introduction mechanism 63, which will be described later, and travel toward the main amplifier 62C.
  • the phase shifter 62A is configured to change the microwave radiation characteristic by changing the phase of the microwave.
  • the phase shifter 62A is used to change the plasma distribution by controlling the directivity of the microwave by adjusting the phase of the microwave for each antenna module 61, for example. If such adjustment of the radiation characteristics is not performed, the phase shifter 62A may not be provided.
  • variable gain amplifier 62B is used for adjusting variations of individual antenna modules 61 and adjusting plasma intensity. For example, by changing the variable gain amplifier 62B for each antenna module 61, the plasma distribution in the entire processing container 2 can be adjusted.
  • the main amplifier 62C includes, for example, an input matching circuit, a semiconductor amplifying element, an output matching circuit, and a high Q resonance circuit.
  • the semiconductor amplifying element for example, GaAs HEMT, GaN HEMT, and LD (Laterally Diffused) -MOS capable of class E operation are used.
  • the isolator 62D has a circulator and a dummy load (coaxial terminator).
  • the circulator guides the reflected microwave reflected by the antenna portion of the microwave introduction mechanism 63 described later to the dummy load.
  • the dummy load converts the reflected microwave guided by the circulator into heat.
  • a plurality of antenna modules 61 are provided, and a plurality of microwaves can be introduced into the processing container 2 by the respective microwave introduction mechanisms 63 of the plurality of antenna modules 61. . Therefore, each isolator 62D may be small, and the isolator 62D can be provided adjacent to the main amplifier 62C.
  • the microwave introduction mechanism 63 includes a tuner 64 that matches impedance, an antenna unit 65 that radiates the amplified microwave into the processing container 2, and a metal material.
  • a main body container 66 having a cylindrical shape extending in the direction, and an inner conductor 67 extending in the same direction as the main container container 66 extends in the main body container 66.
  • the main body container 66 and the inner conductor 67 constitute a coaxial tube.
  • the main body container 66 constitutes the outer conductor of this coaxial tube.
  • the inner conductor 67 has a rod shape or a cylindrical shape. A space between the inner peripheral surface of the main body container 66 and the outer peripheral surface of the inner conductor 67 forms a microwave transmission path 68.
  • the antenna module 61 further includes a power feeding conversion unit provided on the base end side (upper end side) of the main body container 66.
  • the power feeding conversion unit is connected to the main amplifier 62C via a coaxial cable.
  • the isolator 62D is provided in the middle of the coaxial cable.
  • the antenna unit 65 is provided on the opposite side of the main body container 66 from the power conversion unit. As will be described later, a portion of the main body container 66 closer to the base end than the antenna portion 65 is in an impedance adjustment range by the tuner 64.
  • the antenna unit 65 includes a planar antenna 71 connected to the lower end of the inner conductor 67, a microwave slow wave material 72 disposed on the upper surface side of the planar antenna 71, and a planar surface. And a microwave transmission plate 73 disposed on the lower surface side of the antenna 71.
  • the lower surface of the microwave transmission plate 73 is exposed in the internal space of the processing container 2.
  • the microwave transmission plate 73 is fitted into the opening of the ceiling portion 11 that is a conductive member of the microwave introduction device 5 through the main body container 66.
  • the microwave transmission plate 73 corresponds to the microwave transmission window in the present invention.
  • the planar antenna 71 has a disc shape.
  • the planar antenna 71 has a slot 71 a formed so as to penetrate the planar antenna 71.
  • a slot 71 a formed so as to penetrate the planar antenna 71.
  • four slots 71 a are provided, and each slot 71 a has an arc shape that is equally divided into four.
  • the number of slots 71a is not limited to four, but may be five or more, or may be one or more and three or less.
  • the microwave slow wave material 72 is formed of a material having a dielectric constant larger than that of a vacuum.
  • a material for forming the microwave slow wave material 72 for example, fluororesin such as quartz, ceramics, polytetrafluoroethylene resin, polyimide resin, or the like can be used. Microwaves have a longer wavelength in vacuum.
  • the microwave slow wave material 72 has a function of adjusting the plasma by shortening the wavelength of the microwave. Further, the phase of the microwave varies depending on the thickness of the microwave slow wave material 72. Therefore, by adjusting the phase of the microwave according to the thickness of the microwave slow wave material 72, the planar antenna 71 can be adjusted to be at the antinode position of the standing wave. Thereby, while being able to suppress the reflected wave in the planar antenna 71, the radiation energy of the microwave radiated
  • the microwave transmission plate 73 is made of a dielectric material.
  • a dielectric material for forming the microwave transmission plate 73 for example, quartz or ceramics is used.
  • the microwave transmission plate 73 has a shape capable of efficiently radiating microwaves in the TE mode. In the example shown in FIG. 5, the microwave transmission plate 73 has a rectangular parallelepiped shape.
  • the shape of the microwave transmission plate 73 is not limited to a rectangular parallelepiped shape, and may be, for example, a cylindrical shape, a pentagonal column shape, a hexagonal column shape, or an octagonal column shape.
  • the microwave amplified by the main amplifier 62C passes between the inner peripheral surface of the main body container 66 and the outer peripheral surface of the inner conductor 67 (microwave transmission path 68). It passes through the planar antenna 71, passes through the microwave transmitting plate 73 from the slot 71 a of the planar antenna 71, and is radiated to the internal space of the processing container 2.
  • the tuner 64 constitutes a slag tuner. Specifically, as shown in FIG. 4, the tuner 64 includes two slugs 74 ⁇ / b> A and 74 ⁇ / b> B disposed on the base end side (upper end side) of the antenna body 65 of the main body container 66, and 2 An actuator 75 for operating the two slugs 74A and 74B and a tuner controller 76 for controlling the actuator 75 are provided.
  • the slugs 74 ⁇ / b> A and 74 ⁇ / b> B have a plate shape and an annular shape, and are disposed between the inner peripheral surface of the main body container 66 and the outer peripheral surface of the inner conductor 67.
  • the slugs 74A and 74B are made of a dielectric material.
  • a dielectric material for forming the slags 74A and 74B for example, high-purity alumina having a relative dielectric constant of 10 can be used.
  • High-purity alumina usually has a relative dielectric constant larger than that of quartz (relative dielectric constant 3.88) or Teflon (registered trademark) (relative dielectric constant 2.03), which is used as a material for forming slag.
  • the thickness of 74A, 74B can be made small.
  • high-purity alumina has a feature that the dielectric loss tangent (tan ⁇ ) is smaller than that of quartz or Teflon (registered trademark), and the loss of microwaves can be reduced.
  • High-purity alumina further has a feature of low distortion and a feature of being resistant to heat.
  • the high-purity alumina is preferably an alumina sintered body having a purity of 99.9% or more. Further, single crystal alumina (sapphire) may be used as high purity alumina.
  • the tuner 64 moves the slugs 74A and 74B in the vertical direction by the actuator 75 based on a command from the tuner controller 76. Thereby, the tuner 64 adjusts the impedance. For example, the tuner controller 76 adjusts the positions of the slugs 74A and 74B so that the terminal impedance is 50 ⁇ .
  • the main amplifier 62C, the tuner 64, and the planar antenna 71 are arranged close to each other.
  • the tuner 64 and the planar antenna 71 constitute a lumped constant circuit and function as a resonator.
  • the tuner 64 can be tuned with high accuracy including plasma, and the influence of reflection on the planar antenna 71 can be eliminated.
  • the tuner 64 can eliminate impedance mismatch up to the planar antenna 71 with high accuracy, and can substantially make the mismatched portion a plasma space. Thereby, the tuner 64 enables high-precision plasma control.
  • FIG. 7 is a bottom view of the ceiling portion 11 of the processing container 2 shown in FIG.
  • FIG. 8 is an explanatory diagram showing the arrangement of a plurality of microwave transmission plates 73 in the present embodiment.
  • the main body container 66 is not shown.
  • the microwave transmission plate 73 has a cylindrical shape.
  • the microwave introduction device 5 includes a plurality of microwave transmission plates 73.
  • the microwave transmission plate 73 corresponds to the microwave transmission window in the present invention.
  • the plurality of microwave transmission plates 73 are fitted in a plurality of openings of the ceiling portion 11 that is a conductive member of the microwave introduction device 5, and are one virtual parallel to the mounting surface 21 a of the mounting table 21. It is arranged on a plane. Further, the plurality of microwave transmission plates 73 include three microwave transmission plates 73 whose distances between the center points are equal to or substantially equal to each other on the virtual plane.
  • the distances between the center points are substantially equal because the position of the microwave transmission plate 73 is determined from the viewpoint of the shape accuracy of the microwave transmission plate 73 and the assembly accuracy of the antenna module 61 (microwave introduction mechanism 63). It means that it may be slightly deviated from the desired position.
  • the plurality of microwave transmission plates 73 are composed of seven microwave transmission plates 73 arranged so as to have a hexagonal close-packed arrangement. Specifically, each of the plurality of microwave transmission plates 73 has six microwave transmission plates 73A to 73F arranged so that the center points thereof coincide with or substantially coincide with the vertices of a regular hexagon, and the center points thereof are regular six.
  • the microwave transmission plate 73G is arranged so as to coincide with or substantially coincide with the center of the square.
  • symbols P A to P G indicate the center points of the microwave transmission plates 73A to 73G, respectively.
  • substantially matching the vertex or center point means that the center point of the microwave transmitting plate 73 is from the viewpoint of the shape accuracy of the microwave transmitting plate 73 and the assembly accuracy of the antenna module 61 (microwave introducing mechanism 63). , Meaning that it may be slightly deviated from the above vertex or center.
  • the microwave transmission plate 73 ⁇ / b> G is disposed in the central portion of the ceiling portion 11.
  • the six microwave transmission plates 73A to 73F are arranged outside the central portion of the ceiling portion 11 so as to surround the microwave transmission plate 73G. Therefore, the microwave transmission plate 73G corresponds to the central microwave transmission window in the present invention, and the microwave transmission plates 73A to 73F correspond to the outer microwave transmission window in the present invention.
  • the central portion in the ceiling portion 11 means “the central portion in the planar shape of the ceiling portion 11”.
  • the microwave transmission plates 73A to 73G are arranged while satisfying the following first and second conditions.
  • the first condition is that six equilateral triangles are formed in a planar shape by connecting three adjacent central points among the central points P A to P G of the microwave transmitting plates 73A to 73G. is there.
  • the second condition is that a virtual regular hexagon is formed by these six regular triangles. As shown in FIG. 8, when the center points P A to P F of the microwave transmission plates 73A to 73F are connected so as to surround the microwave transmission plate 73G, the above-mentioned virtual regular hexagon is formed.
  • symbol W denotes a figure formed by projecting the planar shape of the wafer W onto a virtual plane on which a plurality of microwave transmission plates 73 are arranged (hereinafter simply referred to as the planar shape of the wafer W). .).
  • the planar shape of the wafer W is circular.
  • the regular hexagonal outer edge that serves as a reference for the center points P A to P F of the microwave transmission plates 73A to 73F includes the planar shape of the wafer W.
  • the center point P G of the microwave transmitting plate 73G is consistent or nearly coincides with the central point of the planar shape of the wafer W (circles).
  • the center points P A to P F of the microwave transmission plates 73A to 73F are arranged at equal or substantially equal intervals on the circumference of a concentric circle with respect to the planar shape of the wafer W.
  • the distances between the center points of arbitrary three microwave transmission plates 73 adjacent to each other are equal to or substantially equal to each other.
  • this will be described taking the microwave transmission plates 73A, 73B, and 73G as an example.
  • the center points P A and P B of the microwave transmission plates 73A and 73B coincide with two adjacent vertices of a regular hexagon.
  • the center point P G of the microwave transmitting plate 73G coincides with the regular hexagon of the center point.
  • the figure drawn by connecting the center points P A , P B , and P G is an equilateral triangle. Accordingly, the center point P A, P B, the distance between P G are equal to each other.
  • microwave transmission plates 73A, 73B, 73G are applicable to any combination of the three microwave transmission plates 73 adjacent to each other. Therefore, in the present embodiment, in all the microwave transmission plates 73, the distances between the center points of arbitrary three microwave transmission plates 73 adjacent to each other are equal to or substantially equal to each other.
  • the microwave introduction mechanism 63 has an integral structure including a microwave transmission plate 73.
  • the plurality of microwave introduction mechanisms 63 includes seven microwave introduction mechanisms 63. Each microwave introduction mechanism 63 is arranged corresponding to the position where the microwave transmission plate 73 shown in FIGS. 7 and 8 is arranged. Further, as shown in FIG. 7, the plurality of nozzles 16 of the gas introduction unit 15 surround the microwave transmission plate 73G between the microwave transmission plates 73A to 73F and the microwave transmission plate 73G. Has been placed.
  • a command is input from the user interface 82 to the process controller 81 so as to perform plasma oxidation processing in the plasma processing apparatus 1.
  • the process controller 81 receives this command, and reads a recipe stored in the storage unit 83 or a computer-readable storage medium.
  • each end device of the plasma processing apparatus 1 for example, the high frequency bias power supply 25, the gas supply apparatus 3a, the exhaust apparatus 4, and the microwave introduction is performed so that the plasma oxidation process is executed according to the conditions based on the recipe.
  • a control signal is sent to the apparatus 5 or the like.
  • the gate valve G is opened, and the wafer W is loaded into the processing container 2 through the gate valve G and the loading / unloading port 12a by a transfer device (not shown).
  • the wafer W is placed on the placement surface 21 a of the placement table 21.
  • the gate valve G is closed, and the inside of the processing container 2 is evacuated by the exhaust device 4.
  • the gas supply mechanism 3 introduces a rare gas and an oxygen-containing gas at a predetermined flow rate into the processing container 2 through the gas introduction unit 15.
  • the internal space of the processing container 2 is adjusted to a predetermined pressure by adjusting the exhaust amount and the gas supply amount.
  • the microwave to be introduced into the processing container 2 is generated in the microwave output unit 50.
  • the plurality of microwaves output from the distributor 54 of the microwave output unit 50 are input to the plurality of antenna modules 61 of the antenna unit 60 and are introduced into the processing container 2 by each antenna module 61.
  • the microwave propagates through the amplifier unit 62 and the microwave introduction mechanism 63.
  • the microwave that has reached the antenna unit 65 of the microwave introduction mechanism 63 passes through the microwave transmission plate 73 from the slot 71 a of the planar antenna 71 and is radiated to the space above the wafer W in the processing chamber 2. In this way, microwaves are individually introduced into the processing container 2 from the respective antenna modules 61.
  • the microwaves introduced into the processing container 2 from a plurality of parts as described above form an electromagnetic field in the processing container 2 respectively.
  • the processing gas such as a rare gas or an oxygen-containing gas introduced into the processing container 2 is turned into plasma.
  • the silicon surface of the wafer W is oxidized by the action of active species in the plasma, such as radicals or ions, to form a silicon oxide film SiO 2 thin film.
  • the wafer W can be nitrided to form a silicon nitride film SiN thin film.
  • the distance between the center points of the microwave transmission plates 73 adjacent to each other is set to be equal to or approximately equal to each other. If the plurality of adjacent microwave transmission plates 73 are arranged so that the distances between their center points are different, the plasma density is biased when the density distribution of the microwave plasma based on each microwave transmission plate 73 is the same. It becomes difficult to maintain the uniformity of processing within the surface of the wafer W.
  • the distance between the center points of the adjacent microwave transmission plates 73 is set to be equal to or substantially equal to each other, so that the density distribution of the microwave plasma is made uniform. Becomes easier. As described above, in the plasma processing apparatus 1, it is possible to make the density distribution of the microwave plasma uniform with a simple configuration, and the processing uniformity within the surface of the wafer W can be obtained.
  • the microwave transmission plate 73G is disposed at the center portion of the ceiling portion 11, and the six microwave transmission plates 73A to 73F are arranged on the ceiling portion 11 so as to surround the microwave transmission plate 73G. It is arrange
  • the configuration of the plurality of antenna modules 61 is the same. Thereby, in the plasma processing apparatus 1, the same plasma generation conditions can be used in each antenna module 61, and the adjustment of the density distribution of the microwave plasma is facilitated.
  • the plasma density below the region corresponding to the inside of the regular hexagon is larger than the plasma density below the region corresponding to the outside of the regular hexagon.
  • the outer edge of the regular hexagon serving as the reference of the center point of the microwave transmission plates 73A to 73F includes the planar shape of the wafer W. Thereby, in the plasma processing apparatus 1, the wafer W can be arrange
  • plasma is generated by a plurality of microwaves in the processing container 2 of the plasma processing apparatus 1 to process the wafer W, which is an object to be processed, and, for example, silicon on the surface of the wafer W is oxidized. Then, a silicon oxide film is formed.
  • total power during ignition the total of a plurality of microwave powers when the plasma is ignited by a plurality of microwaves
  • total power during process the microwave power when igniting plasma from one microwave is “power during ignition”, and the microwave power when processing the wafer W with plasma generated from one microwave is “process power”.
  • a plasma processing apparatus 1 of a plurality of microwaves that generates plasma by a plurality of microwaves in the processing container 2 is used, and the thickness is 1 nm (10 angstroms) or less, preferably 0.5 nm or more and 1 nm or less.
  • plasma oxidation is performed with low microwave power.
  • the total power upon ignition is set to 700 W or less, preferably 560 W or less, more preferably 420 W or less.
  • the total power at the time of ignition is specified as described above in the plasma processing method of the present embodiment.
  • the total power during ignition is about 2 to 3 times larger than the total power during processing. Therefore, if the total power at the time of ignition is 1 W / cm 2 or less per area of the wafer W, the total power during the process is approximately 1 W / cm 2 or less per area of the wafer W, and plasma processing with low power becomes possible.
  • FIG. 9 is a cross-sectional view schematically showing the configuration of a single microwave plasma processing apparatus 501 that generates plasma from one microwave in a processing container.
  • the plasma processing apparatus 501 includes a processing container 502, a mounting table 521, and a support member 522.
  • the configuration of the processing container 502, the mounting table 521, and the supporting member 522 is the same as the configuration of the processing container 2, the mounting table 21, and the supporting member 22 shown in FIG.
  • the plasma processing apparatus 501 includes a microwave introducing device 505 instead of the microwave introducing device 5 shown in FIGS. 1 and 3.
  • the microwave introduction device 505 is provided on the upper portion of the processing container 502.
  • a microwave introduction device having a known configuration including only one microwave transmission plate 573 can be used.
  • the microwave transmission plate 573 has, for example, a disk shape.
  • the diameter of the planar shape of the microwave transmission plate 573 is larger than the diameter of the wafer W, for example, 460 mm.
  • the planar shape of the microwave transmission plates 573 needs to be larger than the planar shape of the wafer W.
  • the microwave power necessary to stably ignite and discharge the plasma also increases.
  • the microwave power (ignition) required to stably ignite and discharge the plasma is 1000 W.
  • the area of the microwave transmission plate 73 can be made smaller than that of the microwave transmission plate 573 of the plasma processing apparatus 501.
  • the diameter of the planar shape of one microwave transmission plate 73 is, for example, in the range of 90 mm to 200 mm, preferably 90 mm to 150 mm. It can be within the following range.
  • the plasma processing apparatus 1 can reduce the microwave power necessary for stably igniting and maintaining discharge of the plasma as compared with the case where the plasma processing apparatus 501 is used.
  • the plasma processing apparatus 1 can perform plasma ignition and discharge maintenance with a low-power microwave, and is suitable for plasma processing in which a thin film having a thickness of 1 nm or less is formed while controlling the film thickness.
  • the main conditions for forming a silicon oxide film having a thickness of 1 nm or less using the plasma processing apparatus 1 are as follows: type and flow rate of processing gas, processing pressure, microwave power, processing temperature, oxidation rate, The processing time and impedance matching procedure will be described in detail. Note that these conditions are stored as recipes in the storage unit 83 of the control unit 8. Then, the process controller 81 reads out the recipe and sends a control signal to each component of the plasma processing apparatus 1, whereby the plasma oxidation process is performed under desired conditions.
  • a processing gas for the plasma oxidation treatment it is preferable to use a rare gas for generating plasma and an oxygen-containing gas.
  • a rare gas for example, Ar, Kr, Xe, He or the like can be used.
  • the oxygen-containing gas for example, O 2 gas, ozone gas, or the like can be used.
  • Ar gas is preferable as the rare gas
  • O 2 gas is preferable as the oxygen-containing gas.
  • the volume flow rate ratio of the oxygen-containing gas to the total processing gas in the processing vessel 2 makes it easy to form a thin film having a thickness of 1 nm or less by appropriately adjusting the oxidizing power. From the viewpoint of, for example, it is preferably in the range of 0.1% to 5%, and more preferably in the range of 0.5% to 3%.
  • the flow rate of the rare gas is set to the above flow rate ratio, for example, within a range of 100 mL / min (sccm) to 10000 mL / min (sccm). It is preferable to set the flow rate of the oxygen-containing gas so that the flow rate ratio is within the range of 0.1 mL / min (sccm) to 500 mL / min (sccm).
  • ⁇ Microwave power> In the plasma processing using the plasma processing apparatus 1, it is preferable to use a microwave of 860 MHz as the microwave. Moreover, the ignition time of the total power, from the viewpoint of facilitating the formation of the following film thickness of 1 nm, per area of the wafer W 1W / cm 2 or less, preferably 0.5 W / cm 2 or more 1W / cm 2 or less in the range among them, more preferably 0.5 W / cm 2 or more 0.8 W / cm 2 within the range, and most preferably 0.5 W / cm 2 or more 0.6 W / cm 2 within the following ranges.
  • the total power at the time of ignition can be 700 W or less, preferably 350 W or more and 700 W or less. If the total power during ignition exceeds 1 W / cm 2 or 700 W, the oxidation rate immediately after plasma ignition becomes high, and it becomes difficult to form a thin film having a thickness of 1 nm or less, or the controllability of the film thickness is remarkably deteriorated. .
  • the lower limit of the total power during ignition is preferably set to 0.5 W / cm 2 or more per area of the wafer W from the viewpoint of generating stable plasma.
  • the power at the time of ignition of the microwaves introduced from one microwave transmission plate 73 can be set to 100 W or less.
  • the total power during the process can be made smaller than the total power during ignition, for example, within a range of about 1/3 to 1/2 of the total power during ignition. can do.
  • the plasma processing apparatus 1 when processing a wafer W 300mm diameter, and the range of ignition when the total power 420W or 700W or less (per area of the wafer W 0.6 W / cm 2 or more 1W / cm 2 or less) Then, it can be in the range of 140W or more 350W less process time total power (per area of the wafer W 0.2 W / cm 2 or more 0.5 W / cm 2 or less).
  • the process power of the microwaves introduced from the one microwave transmission plate 73 can be 50 W or less. Further, depending on the conditions, the total power at the time of ignition can be used as the total power at the time of the process, or the total power at the time of the process can be set higher than the total power at the time of ignition.
  • the plasma processing apparatus 501 of the comparative example when processing a wafer W having a diameter of 300 mm, the minimum value of the ignition power and the process power is 1000 W (1.42 W / cm 2 ). If it is less than this value, stable plasma ignition and discharge maintenance are difficult. Therefore, compared with the plasma processing apparatus 1, the plasma processing apparatus 501 has a higher oxidation rate in the plasma oxidation process, and it is difficult to form a thin film having a thickness of 1 nm or less.
  • the treatment pressure is preferably in the range of 30 Pa to 600 Pa, and more preferably in the range of 80 Pa to 300 Pa.
  • FIG. 10 is a Paschen curve representing the relationship between the pressure and the ignition power when the plasma of Ar gas 100% is ignited using one microwave transmission plate 73 of the plasma processing apparatus 1.
  • the case where the diameter of the microwave transmission plate 73 is 90 mm is compared with the case where the diameter is 150 mm. From this Paschen curve, it is understood that the 90 mm diameter microwave transmission plate 73 may have a smaller ignition power than the 150 mm diameter.
  • the large microwave transmission plate 573 is used as described above, a larger ignition power is required.
  • the microwave transmission plate 73 has a diameter of 90 mm
  • the ignition power is substantially less than 100 W within a range of 30 Pa to 600 Pa, for example.
  • the microwave transmission plate 73 has a diameter of 150 mm, for example, the ignition power is less than about 100 W within a range of 80 Pa to 300 Pa.
  • the processing temperature of the wafer W is preferably, for example, in the range of room temperature (30 ° C.) to 200 ° C., and is preferably 100 ° C. or less. It is more preferable to set.
  • processing temperature means the temperature of the mounting base 21, and room temperature (30 degreeC) means not heating.
  • FIG. 11 is a characteristic diagram showing the relationship between the film thickness of the silicon oxide film and the processing time when the plasma oxidation processing is performed on the silicon on the surface of the wafer W at different processing temperatures.
  • the vertical axis in FIG. 11 indicates the film thickness of the silicon oxide film formed by plasma processing, and the horizontal axis indicates the process time.
  • shaft of FIG. 11 is the film thickness measured with the ellipsometer. In this specification, unless otherwise noted, the film thickness means a value measured by an ellipsometer.
  • the experiment was conducted under conditions a to c.
  • Conditions a and b used the plasma processing apparatus 1 including seven microwave transmission plates 73.
  • the processing temperature was room temperature (30 ° C.)
  • the processing temperature was 500 ° C.
  • a single microwave plasma processing apparatus 501 was used, and the processing temperature was 300 ° C.
  • Conditions other than the temperature of the plasma oxidation process using the plasma processing apparatus 1 are as follows.
  • the interval (gap) between the microwave transmission plate 73 and the wafer W was fixed to 85 mm.
  • the power of the microwave introduced from one microwave transmission plate 73 was set to 60 W during ignition and 20 W during process.
  • the pressure in the processing container 2 was 133 Pa.
  • 990 sccm (mL / min) Ar was used as a rare gas for plasma generation, and 10 sccm (mL / min) O 2 was used as an oxygen-containing gas.
  • the conditions c of the plasma oxidation process using the plasma processing apparatus 501 are as follows. First, the processing temperature (set temperature of the mounting table 521) was set to 300 ° C. The interval (gap) between the microwave transmission plate 573 and the wafer W was 85 mm, the microwave ignition power was 1000 W, and the process power was 1000 W. The pressure in the processing container 502 was 133 Pa. 1980 sccm (mL / min) Ar was used as a rare gas for plasma generation, and 20 sccm (mL / min) O 2 was used as an oxygen-containing gas.
  • the condition a using the plasma processing apparatus 1 for generating plasma with a plurality of microwaves is formed even in the same process time as compared with the condition c using the single microwave plasma processing apparatus 501.
  • the oxide film can be greatly thinned. Note that, in the condition b using the same plasma processing apparatus 1, the oxidation rate is higher than in the condition a, and the controllability in forming a thin film having a thickness of 1 nm or less is lower than the process in the condition a. This is presumably because the processing temperature is as high as 500 ° C. However, it can be seen from FIG. 11 that if the processing temperature is 100 ° C. or less, it is possible to form a silicon oxide film having a thickness of 1 nm or less with good controllability of film thickness.
  • the plasma processing method of the present embodiment is, for example, an average oxidation for 30 seconds after the microwave supply for plasma ignition is started (power ON).
  • the rate is preferably 0.03 nm / second or less, and more preferably 0.005 nm / second or more and 0.03 nm / second or less.
  • the processing time is not particularly limited as long as the silicon oxide film can be formed with a desired thickness of 1 nm or less.
  • the processing time is microscopic for plasma ignition. For example, it is preferably within a range of 10 seconds or more and 100 seconds or less with reference to the time point when the supply of wave power is started (power ON).
  • impedance matching procedure in the plasma processing method of the present embodiment will be described with reference to FIGS. 12A and 12B and FIGS. 13A and 13B.
  • impedance matching is not performed when plasma is ignited by a plurality of microwaves, and impedance matching is performed when the wafer W is processed by plasma generated by a plurality of microwaves.
  • impedance matching is performed by vertically moving the two slugs 74A and 74B of the tuner 64 (see FIG. 4).
  • FIGS. 12A and 12B show the relationship between the impedance matching procedure and plasma emission when a microwave is introduced from one microwave transmission plate 73 of the plasma processing apparatus 1 to ignite oxygen plasma, respectively.
  • the vertical axis of FIGS. 12A and 12B indicates the emission intensity ratio of oxygen radicals at a wavelength of 777 nm by emission spectroscopic analysis (OES), and the horizontal axis indicates the set power of the microwave.
  • the square plots (with matching) in FIGS. 12A and 12B are plasmas obtained by impedance matching using a mixed gas of Ar gas and O 2 gas containing 1% by volume of O 2 gas as a processing gas at a pressure of 133 Pa. 3 shows the relationship between the set power and the light emission intensity in the case of generating.
  • FIGS. 12A and 12B show plasma without impedance matching using a mixed gas of Ar gas and O 2 gas containing 1% by volume of O 2 gas as a processing gas at a pressure of 133 Pa. 3 shows the relationship between the set power and the light emission intensity in the case of generating.
  • FIGS. 13A and 13B are timing charts showing impedance matching procedures when a microwave is introduced from one microwave transmission plate 73 of the plasma processing apparatus 1 to ignite oxygen plasma.
  • the horizontal axis indicates time
  • t1 is the start of process gas introduction
  • t2 is plasma ignition by microwave introduction
  • t3 is switching to process power
  • t4 is process end (microwave stop)
  • t5 Indicates the timing of stopping the supply of the processing gas.
  • Ar gas and O 2 gas are simultaneously introduced into the processing container 2 as processing gases to ignite the plasma.
  • Ar gas is first introduced into the processing container 2. May be introduced to ignite the plasma, and O 2 gas may be introduced later.
  • Method A shows a method of starting impedance matching simultaneously with plasma ignition (hereinafter referred to as method A).
  • the change in emission intensity in this case is indicated by a thick arrow in FIG. 12A.
  • the plasma is ignited with an ignition power of 100 W (time t2), and simultaneously impedance matching is started with the ignition power, and the impedance is matched and the process power is shifted to 50 W ( Time t3).
  • FIG. 12B and FIG. 13B show a method of starting impedance matching (hereinafter referred to as method B) when the process is shifted to the process without starting impedance matching simultaneously with plasma ignition.
  • the change in emission intensity in this case is indicated by a thick arrow in FIG. 12B.
  • plasma is ignited with an ignition power of 100 W (time t2), and after ignition, the process shifts to a process power of 50 W without performing impedance matching (time t3), and impedance matching is started with the process power.
  • Method B impedance matching is not performed with ignition power, so that the amount of oxygen radicals, which are oxidation active species in plasma, can be greatly suppressed compared to Method A during plasma ignition.
  • FIGS. 12A and 12B show the case where plasma is generated by one microwave.
  • the method B similarly applies.
  • the amount of oxygen radicals, which are oxidation active species in plasma can be significantly suppressed during plasma ignition. Therefore, by adopting the procedure of the method B, compared with the procedure of the method A, in the formation of the thin film (silicon oxide film) using the plasma processing apparatus 1, the oxidation at the time of plasma ignition can be suppressed. Controllability is improved and further thinning is possible. The experimental results confirming this will be described with reference to FIG.
  • FIG. 14 is a characteristic diagram showing the relationship between the film thickness of the silicon oxide film formed by plasma processing and the process time.
  • the vertical axis in FIG. 14 indicates the film thickness of the silicon oxide film formed by plasma treatment, and the horizontal axis indicates the process time.
  • the experiment was performed under the following conditions 1 to 4.
  • Conditions 1 to 3 used the plasma processing apparatus 1 including seven microwave transmission plates 73, and
  • Condition 4 used a single microwave plasma processing apparatus 501 for comparison.
  • An ellipsometer was used to measure the thickness of the silicon oxide film.
  • Plasma generation method Multiple microwaves Total power at ignition: 420W Total power during process: 140W Power at ignition: 60W Process power: 20W Impedance matching: Method B ⁇ Condition 2> Plasma generation method: Multiple microwaves Total power at ignition: 700W Total power during process: 350W Ignition power: 100W Process power: 50W Impedance matching: Method B ⁇ Condition 3> Plasma generation method: Multiple microwaves Total power at ignition: 700W Total power during process: 350W Ignition power: 100W Process power: 50W Impedance matching: Method A ⁇ Condition 4> Plasma generation method: Single microwave Ignition power: 1000W Process power: 1000W Impedance matching: Method A
  • the interval (gap) between the microwave transmission plate 73 and the wafer W was fixed to 85 mm.
  • the pressure in the processing container 2 was 133 Pa.
  • 990 sccm (mL / min) Ar was used as a rare gas for plasma generation, and 10 sccm (mL / min) O 2 was used as an oxygen-containing gas.
  • the processing temperature was 30 ° C.
  • the interval (gap) between the microwave transmission plate 573 and the wafer W was set to 85 mm. 1980 sccm (mL / min) Ar was used as a rare gas for plasma generation, and 20 sccm (mL / min) O 2 was used as an oxygen-containing gas.
  • the processing temperature was 300 ° C.
  • the conditions 1 to 3 using the plasma processing apparatus 1 for generating plasma with a plurality of microwaves are compared to the condition 4 using the single microwave plasma processing apparatus 501 and the total power and process during ignition. Since both the time total power is small, the silicon oxide film formed even in the same process time can be greatly thinned.
  • the film thickness of the silicon oxide film was 1 nm or less even after 20 seconds had elapsed from the start of the process (process time 0), and impedance matching was performed by method A. Even when compared with condition 3, good results were obtained.
  • condition 4 since the oxidation rate is too large, it is practically impossible to control the thickness of the silicon oxide film to 1 nm or less.
  • the process time 0 is switched to the process power after the microwave power is turned on (ON) and the plasma is ignited and stabilized for 5 seconds in both the method A and the method B (FIG. 14). 13A and 13B at time t3), and the time at which the process power is stabilized for 5 seconds. Therefore, in FIG. 14, the process time 0 is about 10 seconds after the microwave power is turned on (ON) in both the method A and the method B. Therefore, under conditions 1 to 3 in FIG. 14, even if the process time is 0, the thickness of the silicon oxide film of about 0.9 nm has already been measured.
  • the average oxidation rate from the process time 0 to 20 seconds later is clearly about 0.005 nm / second.
  • plasma processing at such a low oxidation rate is possible.
  • the silicon oxide film can be formed with an arbitrary film thickness of 1 nm or less with good controllability.
  • a silicon oxide film having a thickness of 1 nm or less can be formed on the surface of the wafer W, which is an object to be processed, with good controllability of the thickness.
  • plasma processing method according to the second embodiment of the present invention performed using the plasma processing apparatus 1 is generated in a processing container 2 of a plasma processing apparatus 1 by a plurality of microwaves to process a wafer W as an object to be processed, for example, nitriding silicon on the surface of the wafer W Then, a silicon nitride film is formed.
  • a plasma processing apparatus 1 that generates plasma by a plurality of microwaves in the processing container 2 is used, and the thickness is 1 nm (10 angstroms) or less, preferably 0.5 nm or more and 1 nm or less.
  • plasma nitriding is performed with low microwave power.
  • the total power during ignition, per area of the wafer W 1W / cm 2 or less preferably 0.8 W / cm 2 or less, more preferably 0.6 W / cm 2 or less.
  • the total power upon ignition is set to 700 W or less, preferably 560 W or less, more preferably 420 W or less.
  • the main conditions for forming a silicon nitride film having a thickness of 1 nm or less using the plasma processing apparatus 1 are as follows: type and flow rate of processing gas, processing pressure, microwave power, processing temperature, nitriding rate, The processing time and impedance matching procedure will be described in detail. Note that these conditions are stored as recipes in the storage unit 83 of the control unit 8. Then, the process controller 81 reads the recipe and sends a control signal to each component of the plasma processing apparatus 1, so that the plasma nitriding process is performed under a desired condition.
  • a processing gas for plasma nitriding it is preferable to use a rare gas for generating plasma and a nitrogen-containing gas.
  • a rare gas for example, Ar, Kr, Xe, He or the like can be used.
  • the nitrogen-containing gas for example, nitrogen gas, NH 3 gas or the like is used.
  • Ar gas is preferable as the rare gas
  • N 2 gas is preferable as the nitrogen-containing gas.
  • the volume flow ratio of the nitrogen-containing gas to the total processing gas in the processing container 2 (nitrogen-containing gas flow rate / percentage of the total processing gas flow rate) is easy to form a thin film having a thickness of 1 nm or less by appropriately adjusting the nitriding power.
  • the flow rate of the rare gas is preferably set to be within the range of 100 mL / min (sccm) or more and 10000 mL / min (sccm) or less so that the above flow rate ratio is obtained.
  • the flow rate of the nitrogen-containing gas is preferably set to be within the range of 5 mL / min (sccm) or more and 2500 mL / min (sccm) or less so that the above flow rate ratio is obtained.
  • the total power during ignition is 1 W / cm 2 or less, preferably 0.5 W / cm 2 per area of the wafer W from the viewpoint of facilitating formation of a thin film having a thickness of 1 nm or less.
  • 1W / cm 2 within the range more preferably 0.5 W / cm 2 or more 0.8 W / cm 2 within the range, most preferably 0.5 W / cm 2 or more 0.6 W / cm 2 or less in the range Within.
  • the total power at the time of ignition can be 700 W or less, preferably 350 W or more and 700 W or less.
  • the lower limit of the total power during ignition is preferably set to 0.5 W / cm 2 or more per area of the wafer W from the viewpoint of generating stable plasma.
  • the power at the time of ignition of the microwaves introduced from one microwave transmission plate 73 can be set to 100 W or less.
  • the total power during the process can be made smaller than the total power during ignition, for example, within a range of about 1/3 to 1/2 of the total power during ignition. can do.
  • the plasma processing apparatus 1 when processing a wafer W 300mm diameter, and the range of ignition when the total power 420W or 700W or less (per area of the wafer W 0.6 W / cm 2 or more 1W / cm 2 or less) Then, it can be in the range of 140W or more 350W less process time total power (per area of the wafer W 0.2 W / cm 2 or more 0.5 W / cm 2 or less).
  • the process power of the microwaves introduced from the one microwave transmission plate 73 can be 50 W or less. Further, depending on the conditions, the total power at the time of ignition can be used as the total power at the time of the process, or the total power at the time of the process can be set higher than the total power at the time of ignition.
  • the minimum value of the ignition power and the process power is 1000 W. It is (1.42 W / cm 2 ), and it is difficult to stably ignite plasma and maintain discharge below this value. Therefore, in the plasma processing apparatus 501, compared with the plasma processing apparatus 1, the nitriding rate in the plasma nitriding process is high, and it is difficult to form a thin film having a thickness of 1 nm or less.
  • the treatment pressure is preferably in the range of 10 Pa to 600 Pa, and more preferably in the range of 20 Pa to 300 Pa.
  • the processing temperature of the wafer W is preferably, for example, in the range of room temperature (30 ° C.) to 200 ° C., and is preferably 100 ° C. or less. It is more preferable to set.
  • processing temperature means the temperature of the mounting base 21, and room temperature (30 degreeC) means not heating.
  • the plasma processing method of the present embodiment has an average nitriding rate for 30 seconds after the supply of microwaves for plasma ignition is started (power ON), for example. Is preferably 0.05 nm / second or less, and more preferably 0.005 nm / second or more and 0.05 nm / second or less.
  • the average nitriding rate is controlled in 30 seconds from the start of microwave supply to 0.05 nm / second or less, the controllability of the film thickness is enhanced even in a short processing time, and the film thickness is 1 nm or less, preferably 0.5 nm to 1 nm.
  • a thin film can be formed with a thickness.
  • the processing time is not particularly limited as long as the silicon nitride film can be formed with a desired thickness of 1 nm or less. For example, it is preferably within a range of 10 seconds or more and 100 seconds or less with reference to the time point when the supply of wave power is started (power ON).
  • the impedance matching procedure in the plasma processing method of the present embodiment is the same as the impedance matching procedure in the first embodiment. Also in this embodiment, by adopting the method B, nitriding at the time of plasma ignition can be suppressed in the formation of a thin film (silicon nitride film) using the plasma processing apparatus 1 as compared with the method A. The controllability of the film becomes better, and it becomes possible to further reduce the film thickness.
  • FIG. 15 is a characteristic diagram showing the relationship between the film thickness of the silicon nitride film formed by plasma processing and the process time.
  • the vertical axis in FIG. 15 indicates the film thickness of the silicon nitride film formed by plasma processing, and the horizontal axis indicates the process time.
  • the experiment was performed using the plasma processing apparatus 1 including seven microwave transmission plates 73 under the following conditions. The interval (gap) between the microwave transmission plate 73 and the wafer W was fixed to 85 mm. The total power during ignition was set to 700 W, the total power during process was set to 350 W, the power during ignition was set to 100 W, and the power during process was set to 50 W.
  • the pressure in the processing container 2 was 20 Pa. 1000 sccm (mL / min) Ar was used as a rare gas for plasma generation, and 20 sccm (mL / min) N 2 was used as a nitrogen-containing gas.
  • the processing temperature was 30 ° C. Impedance matching was performed by method B (see the first embodiment) in which impedance matching is not started at the same time as plasma ignition, but impedance matching is started when the process proceeds. An ellipsometer was used to measure the thickness of the silicon nitride film.
  • the process starts (process time 0). It was confirmed that the film thickness of the silicon nitride film could be controlled to 1 nm or less even after 10 seconds.
  • the process time 0 is the time when the microwave power is turned on (ON) and the plasma is ignited, and is stabilized for 5 seconds, and then switched to the process power. It means the time of stabilization over a second. Therefore, in FIG. 15, the process time 0 has passed about 10 seconds after the microwave power is turned on. Therefore, in FIG. 15, even when the process time is 0, the thickness of the silicon nitride film of about 0.5 nm has already been measured. Thus, considering the film thickness formed before the process time 0, the average nitridation rate from the process time 0 to 10 seconds later is clearly about 0.05 nm / sec. Further, by performing impedance matching by the method B, nitridation by plasma immediately after ignition until reaching the process time 0 can be effectively suppressed.
  • a silicon nitride film having a thickness of 1 nm or less can be formed on the surface of the wafer W that is an object to be processed with good controllability of the film thickness.
  • the plasma processing method of the present invention is not limited to a case where a semiconductor wafer is used as an object to be processed, but can also be applied to a case where, for example, a solar cell panel substrate or a flat panel display substrate is used as an object to be processed.
  • the processing target is not limited to silicon.
  • the target of the plasma oxidation process may be a silicon nitride film (SiN film), and the target of the plasma nitridation process may be a silicon oxide film (SiO 2 film) or another type of film.

Abstract

Using a plasma treatment device of a design whereby a plurality of microwaves are introduced into a treatment receptacle and a plasma is generated, the plasma is generated such that the total power of the plurality of microwaves is 1 W/cm2 or less per unit surface area of a wafer (W). For example, in a plasma oxidation treatment, employing an oxygen-containing gas and a noble gas for plasma generation, the treatment temperature is set to 100ºC or below, and the average oxidation rate during the 30 seconds following the outset of supply of microwaves to 0.03 nm/sec or less. In preferred practice, impedance matching takes placed when the wafer (W) is treated by the plasma, rather than impedance matching taking place when a plasma is ignited by the microwaves.

Description

プラズマ処理方法及びプラズマ処理装置Plasma processing method and plasma processing apparatus
　本発明は、プラズマを用いて被処理体にシリコン酸化膜（ＳｉＯ２膜）、シリコン窒化膜（ＳｉＮ膜）などの薄膜を形成するプラズマ処理方法及びこれに用いるプラズマ処理装置に関する。 The present invention relates to a plasma processing method for forming a thin film such as a silicon oxide film (SiO 2 film) and a silicon nitride film (SiN film) on an object to be processed using plasma, and a plasma processing apparatus used therefor.
　半導体デバイスの製造過程では、プラズマを用いて、被処理体に対して例えば酸化処理、窒化処理等の成膜処理が行われている。最近では、次世代以降のデバイス開発に向けて、微細化への対応が益々求められており、成膜処理においても、極薄膜を均一な厚みで形成する技術への要求が高まっている。 In the manufacturing process of a semiconductor device, a film forming process such as an oxidation process or a nitriding process is performed on an object to be processed using plasma. Recently, in order to develop devices for the next generation and beyond, there is an increasing demand for miniaturization, and there is an increasing demand for a technique for forming an ultrathin film with a uniform thickness in the film formation process.
　半導体ウエハ上への薄膜形成に関する従来技術として、特許文献１（国際公開ＷＯ２００２／０５８１３０）では、複数のスロットを有する平面アンテナを用いて処理容器内にマイクロ波を導入してプラズマを生成させるスロットアンテナ方式のプラズマ処理装置を用いて、シリコン酸化膜を形成する技術が提案されている。 As a conventional technique for forming a thin film on a semiconductor wafer, Patent Document 1 (International Publication WO2002 / 058130) discloses a slot antenna that generates plasma by introducing a microwave into a processing container using a planar antenna having a plurality of slots. A technique for forming a silicon oxide film using a plasma processing apparatus of the type has been proposed.
　上記特許文献１に記載されたプラズマ処理方法では、概ね１．６ｎｍ程度の薄いシリコン酸化膜を形成できると考えられる。しかし、今後、次世代以降のデバイス開発においては、さらに薄い膜厚で薄膜を形成することが期待される。 In the plasma processing method described in Patent Document 1, it is considered that a thin silicon oxide film of about 1.6 nm can be formed. However, in future device development, it is expected to form a thin film with a thinner film thickness.
　従って、プラズマを利用して、被処理体の表面に、例えば厚さ１ｎｍ以下の薄膜を、膜厚をコントロールしながら形成する方法が求められていた。 Therefore, there has been a demand for a method of forming a thin film having a thickness of, for example, 1 nm or less on the surface of an object to be processed while controlling the film thickness using plasma.
　本発明のプラズマ処理方法は、複数のマイクロ波により処理容器内にプラズマを生成させて被処理体を処理するプラズマ処理装置を用い、前記被処理体の表面に薄膜を形成する方法である。 The plasma processing method of the present invention is a method of forming a thin film on the surface of the object to be processed using a plasma processing apparatus for processing the object to be processed by generating plasma in a processing container using a plurality of microwaves.
　本発明のプラズマ処理方法は、前記複数のマイクロ波によりプラズマを着火するときのマイクロ波のパワーの合計が前記被処理体の面積当たり１Ｗ／ｃｍ２以下であり、かつ、前記薄膜の膜厚が１ｎｍ以下であってもよい。あるいは、本発明のプラズマ処理方法は、前記被処理体の径が３００ｍｍ以上であり、前記複数のマイクロ波によりプラズマを着火するときのマイクロ波のパワーの合計が７００Ｗ以下であり、かつ、前記薄膜の膜厚が１ｎｍ以下であってもよい。 In the plasma processing method of the present invention, the total power of microwaves when the plasma is ignited by the plurality of microwaves is 1 W / cm 2 or less per area of the object to be processed, and the film thickness of the thin film is It may be 1 nm or less. Alternatively, in the plasma processing method of the present invention, the diameter of the object to be processed is 300 mm or more, the total power of microwaves when the plasma is ignited by the plurality of microwaves is 700 W or less, and the thin film The film thickness may be 1 nm or less.
　また、本発明のプラズマ処理方法は、前記プラズマにより被処理体を処理する処理温度が、１００℃以下である。 Further, in the plasma processing method of the present invention, the processing temperature for processing the object to be processed by the plasma is 100 ° C. or less.
　また、本発明のプラズマ処理方法は、前記薄膜が、前記被処理体の表面のシリコンが酸化されたシリコン酸化膜であってもよいし、前記被処理体の表面のシリコンが窒化されたシリコン窒化膜であってもよい。 In the plasma processing method of the present invention, the thin film may be a silicon oxide film in which silicon on the surface of the object to be processed is oxidized, or silicon nitride in which silicon on the surface of the object to be processed is nitrided It may be a membrane.
　また、本発明のプラズマ処理方法において、前記プラズマ処理装置は、被処理体を収容する前記処理容器と、前記処理容器の内部に配置され、前記被処理体を載置する載置面を有する載置台と、前記処理容器内に処理ガスを供給するガス供給機構と、を備えていてもよい。また、本発明のプラズマ処理方法において、前記プラズマ処理装置は、前記マイクロ波を生成すると共に、該マイクロ波を複数の経路に分配して出力するマイクロ波出力部と、前記マイクロ波出力部から出力された複数のマイクロ波をそれぞれ前記処理容器内に導入する複数のアンテナ部と、前記複数のアンテナ部にそれぞれ対応して設けられて前記マイクロ波出力部と前記処理容器内との間のインピーダンスを整合させる複数のチューナと、を備えていてもよい。さらに、本発明のプラズマ処理方法において、前記プラズマ処理装置は、前記処理容器の上部に配置され、複数の開口部を有する導電性部材と、前記複数の開口部に嵌合し、前記処理容器内に前記マイクロ波を透過させて導入させる複数のマイクロ波透過窓と、を備えていてもよい。そして、本発明のプラズマ処理方法は、前記複数のマイクロ波透過窓からそれぞれ前記処理容器内に導入した前記複数のマイクロ波によって前記プラズマを生成するものであってもよい。 In the plasma processing method of the present invention, the plasma processing apparatus includes the processing container that houses the object to be processed, and a mounting surface that is disposed inside the processing container and mounts the object to be processed. You may provide the mounting base and the gas supply mechanism which supplies process gas in the said process container. In the plasma processing method of the present invention, the plasma processing apparatus generates the microwave, distributes the microwave to a plurality of paths, and outputs the microwave, and outputs the microwave from the microwave output unit. A plurality of antenna portions for introducing the plurality of microwaves into the processing container, and impedance between the microwave output portion and the processing container provided corresponding to the plurality of antenna portions, respectively. And a plurality of tuners to be matched. Furthermore, in the plasma processing method of the present invention, the plasma processing apparatus is disposed in an upper part of the processing container, and is fitted into the conductive member having a plurality of openings and the plurality of openings, And a plurality of microwave transmission windows through which the microwave is transmitted. In the plasma processing method of the present invention, the plasma may be generated by the plurality of microwaves introduced into the processing container from the plurality of microwave transmission windows.
　また、本発明のプラズマ処理方法において、前記複数のマイクロ波により前記プラズマを着火するときの前記マイクロ波のパワーの合計は、前記プラズマにより被処理体を処理するときの前記マイクロ波のパワーの合計よりも大きくてもよい。この場合、前記複数のマイクロ波により前記プラズマを着火するときには前記インピーダンスの整合を行わず、前記プラズマにより被処理体を処理するときに前記インピーダンスの整合を行ってもよい。 In the plasma processing method of the present invention, the total power of the microwaves when the plasma is ignited by the plurality of microwaves is the total power of the microwaves when the object to be processed is processed by the plasma. May be larger. In this case, the impedance matching may not be performed when the plasma is ignited by the plurality of microwaves, and the impedance matching may be performed when the object to be processed is processed by the plasma.
　また、本発明のプラズマ処理方法は、前記マイクロ波出力部から、前記複数のマイクロ波を、前記プラズマを着火させる第１のパワーで供給して前記プラズマを着火するステップと、前記マイクロ波のパワーを前記第１のパワーよりも低い第２のパワーに変更するステップと、前記第２のパワーの状態で前記インピーダンスの整合を行うステップと、を含んでいてもよい。 The plasma processing method of the present invention includes a step of igniting the plasma by supplying the plurality of microwaves from the microwave output unit with a first power for igniting the plasma, and a power of the microwave. May be changed to a second power lower than the first power, and the impedance matching may be performed in the state of the second power.
　また、本発明のプラズマ処理方法において、前記複数のマイクロ波透過窓は、前記導電性部材における中央部分に配置された１つの中心マイクロ波透過窓と、前記中心マイクロ波透過窓を囲むように、前記中央部分よりも外側に配置された少なくとも６つの外側マイクロ波透過窓とを有していてもよい。 Further, in the plasma processing method of the present invention, the plurality of microwave transmission windows surround one central microwave transmission window disposed in a central portion of the conductive member, and the central microwave transmission window, You may have the at least 6 outer side microwave transmission window arrange | positioned outside the said center part.
　本発明のプラズマ処理装置は、複数のマイクロ波により処理容器内にプラズマを生成させて被処理体の表面に薄膜を形成するプラズマ処理装置である。このプラズマ処理装置は、被処理体を収容する処理容器と、前記処理容器の内部に配置され、前記被処理体を載置する載置面を有する載置台と、前記処理容器内に処理ガスを供給するガス供給機構と、を備えている。また、本発明のプラズマ処理装置は、前記マイクロ波を生成すると共に、該マイクロ波を複数の経路に分配して出力するマイクロ波出力部と、前記マイクロ波出力部から出力された複数のマイクロ波をそれぞれ前記処理容器内に導入する複数のアンテナ部と、前記複数のアンテナ部にそれぞれ対応して設けられて前記マイクロ波出力部と前記処理容器内との間のインピーダンスを整合させる複数のチューナと、を備えている。さらに、本発明のプラズマ処理装置は、前記処理容器の上部に配置され、複数の開口部を有する導電性部材と、前記複数の開口部に嵌合し、前記処理容器内に前記マイクロ波を透過させて導入させる複数のマイクロ波透過窓と、を備えている。そして、本発明のプラズマ処理装置は、前記処理容器内で前記複数のマイクロ波によりプラズマを着火するときのマイクロ波のパワーの合計が、前記被処理体の面積当たり１Ｗ／ｃｍ２以下となるように、前記複数のマイクロ波透過窓から、それぞれ前記処理容器内にマイクロ波を導入することにより、前記薄膜の膜厚を１ｎｍ以下に制御する制御部を備えている。 The plasma processing apparatus of the present invention is a plasma processing apparatus that forms a thin film on the surface of an object to be processed by generating plasma in a processing container using a plurality of microwaves. The plasma processing apparatus includes a processing container that accommodates an object to be processed, a mounting table that is disposed inside the processing container and has a mounting surface on which the object to be processed is mounted, and a processing gas that flows into the processing container. And a gas supply mechanism for supplying. In addition, the plasma processing apparatus of the present invention generates a microwave, distributes the microwave to a plurality of paths, and outputs the microwave, and a plurality of microwaves output from the microwave output unit A plurality of antenna portions for introducing a plurality of antennas into the processing vessel, and a plurality of tuners provided corresponding to the plurality of antenna portions to match impedances between the microwave output portion and the processing vessel, respectively. It is equipped with. Furthermore, the plasma processing apparatus of the present invention is disposed at the upper portion of the processing container, and is fitted with the conductive member having a plurality of openings and the plurality of openings, and transmits the microwave into the processing container. And a plurality of microwave transmission windows to be introduced. In the plasma processing apparatus of the present invention, the total power of the microwaves when the plasma is ignited by the plurality of microwaves in the processing container is 1 W / cm 2 or less per area of the object to be processed. In addition, a control unit is provided for controlling the film thickness of the thin film to 1 nm or less by introducing microwaves into the processing container from the plurality of microwave transmission windows.
　本発明のプラズマ処理方法及びプラズマ処理装置によれば、被処理体の表面に、例えば１ｎｍ以下の膜厚の薄膜を制御性よく形成することができる。 According to the plasma processing method and the plasma processing apparatus of the present invention, a thin film having a thickness of, for example, 1 nm or less can be formed on the surface of an object to be processed with good controllability.
本発明の実施の形態で用いるプラズマ処理装置の概略の構成を示す断面図である。It is sectional drawing which shows the schematic structure of the plasma processing apparatus used by embodiment of this invention. 図１に示した制御部の構成を示す説明図である。It is explanatory drawing which shows the structure of the control part shown in FIG. 図１に示したマイクロ波導入装置の構成を示す説明図である。It is explanatory drawing which shows the structure of the microwave introduction apparatus shown in FIG. 図３に示したマイクロ波導入機構を示す断面図である。It is sectional drawing which shows the microwave introduction mechanism shown in FIG. 図４に示したマイクロ波導入機構のアンテナ部を示す斜視図である。It is a perspective view which shows the antenna part of the microwave introduction mechanism shown in FIG. 図４に示したマイクロ波導入機構の平面アンテナを示す平面図である。It is a top view which shows the planar antenna of the microwave introduction mechanism shown in FIG. 図１に示した処理容器の天井部の底面図である。It is a bottom view of the ceiling part of the processing container shown in FIG. 図１に示したマイクロ波導入装置における複数のマイクロ波透過板の配置を示す説明図であるIt is explanatory drawing which shows arrangement | positioning of the several microwave permeation | transmission board in the microwave introduction apparatus shown in FIG. 比較例のプラズマ処理装置の構成を模式的に示す断面図である。It is sectional drawing which shows typically the structure of the plasma processing apparatus of a comparative example. 図１に示したプラズマ処理装置における圧力と着火時パワーの関係を表すパッシェン（Paschen）カーブである。2 is a Paschen curve representing the relationship between pressure and ignition power in the plasma processing apparatus shown in FIG. 異なる処理温度でプラズマ酸化処理をした場合のシリコン酸化膜の膜厚と処理時間との関係を示す特性図である。It is a characteristic view which shows the relationship between the film thickness of a silicon oxide film at the time of performing plasma oxidation processing at different processing temperature, and processing time. 図１に示したプラズマ処理装置で酸素プラズマを着火させる際のインピーダンス整合の手順とプラズマ発光との関係を示す特性図である。It is a characteristic view which shows the relationship between the procedure of impedance matching at the time of igniting oxygen plasma with the plasma processing apparatus shown in FIG. 1, and plasma light emission. 図１に示したプラズマ処理装置で酸素プラズマを着火させる際のインピーダンス整合の別の手順とプラズマ発光との関係を示す特性図である。It is a characteristic view which shows the relationship between another procedure of impedance matching at the time of igniting oxygen plasma with the plasma processing apparatus shown in FIG. 1, and plasma light emission. 図１に示したプラズマ処理装置で酸素プラズマを着火させる際のインピーダンス整合の手順を示すタイミングチャートである。It is a timing chart which shows the procedure of the impedance matching at the time of igniting oxygen plasma with the plasma processing apparatus shown in FIG. 図１に示したプラズマ処理装置で酸素プラズマを着火させる際のインピーダンス整合の別の手順を示すタイミングチャートである。It is a timing chart which shows another procedure of the impedance matching at the time of igniting oxygen plasma with the plasma processing apparatus shown in FIG. プラズマ処理によって形成されたシリコン酸化膜の膜厚とプロセス時間との関係を示す特性図である。It is a characteristic view which shows the relationship between the film thickness of the silicon oxide film formed by plasma processing, and process time. プラズマ処理によって形成されたシリコン窒化膜の膜厚とプロセス時間との関係を示す特性図である。It is a characteristic view which shows the relationship between the film thickness of the silicon nitride film formed by plasma processing, and process time.
　以下、本発明の実施の形態について図面を参照して詳細に説明する。始めに、図１および図２を参照して、本発明の実施の形態のプラズマ処理方法に用いるプラズマ処理装置の構成例について説明する。図１は、本実施の形態で用いるプラズマ処理装置の概略の構成を示す断面図である。図２は、図１に示した制御部の構成を示す説明図である。本実施の形態で用いるプラズマ処理装置１は、連続する複数の動作を伴って、例えば半導体デバイス製造用の半導体ウエハ（以下、単に「ウエハ」と記す。）Ｗに対して、プラズマ酸化処理、プラズマ窒化処理などの成膜処理を施す装置である。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, a configuration example of a plasma processing apparatus used in the plasma processing method according to the embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus used in the present embodiment. FIG. 2 is an explanatory diagram illustrating a configuration of the control unit illustrated in FIG. 1. The plasma processing apparatus 1 used in the present embodiment involves, for example, plasma oxidation processing and plasma processing on a semiconductor wafer (hereinafter simply referred to as “wafer”) W for manufacturing semiconductor devices, with a plurality of continuous operations. This is an apparatus for performing a film forming process such as a nitriding process.
　プラズマ処理装置１は、被処理体であるウエハＷを収容する処理容器２と、処理容器２の内部に配置され、ウエハＷを載置する載置面２１ａを有する載置台２１と、処理容器２内にガスを供給するガス供給機構３と、処理容器２内を減圧排気する排気装置４と、を備えている。また、プラズマ処理装置１は、処理容器２内にプラズマを生成させるためのマイクロ波を発生させると共に、処理容器２内にマイクロ波を導入するマイクロ波導入装置５と、これらプラズマ処理装置１の各構成部を制御する制御部８とを備えている。なお、処理容器２内にガスを供給する手段としては、ガス供給機構３の代りに、プラズマ処理装置１の構成には含まれない外部のガス供給機構を使用してもよい。 The plasma processing apparatus 1 includes a processing container 2 that accommodates a wafer W that is an object to be processed, a mounting table 21 that is disposed inside the processing container 2 and has a mounting surface 21 a on which the wafer W is mounted, and a processing container 2. A gas supply mechanism 3 for supplying gas therein and an exhaust device 4 for evacuating the inside of the processing container 2 under reduced pressure are provided. Further, the plasma processing apparatus 1 generates a microwave for generating plasma in the processing container 2 and introduces a microwave into the processing container 2, and each of the plasma processing apparatuses 1. And a control unit 8 for controlling the components. As a means for supplying the gas into the processing container 2, an external gas supply mechanism that is not included in the configuration of the plasma processing apparatus 1 may be used instead of the gas supply mechanism 3.
　処理容器２は、例えば略円筒形状をなしている。処理容器２は、例えばアルミニウムおよびその合金等の金属材料によって形成されている。マイクロ波導入装置５は、処理容器２の上部に設けられ、処理容器２内に電磁波（マイクロ波）を導入してプラズマを生成するプラズマ生成手段として機能する。マイクロ波導入装置５の構成については、後で詳しく説明する。 The processing container 2 has a substantially cylindrical shape, for example. The processing container 2 is made of a metal material such as aluminum and an alloy thereof. The microwave introduction device 5 is provided in the upper part of the processing container 2 and functions as a plasma generating unit that introduces electromagnetic waves (microwaves) into the processing container 2 to generate plasma. The configuration of the microwave introduction device 5 will be described in detail later.
　処理容器２は、板状の天井部１１および底部１３と、天井部１１と底部１３とを連結する側壁部１２とを有している。天井部１１は、複数の開口部を有している。側壁部１２は、処理容器２に隣接する図示しない搬送室との間でウエハＷの搬入出を行うための搬入出口１２ａを有している。処理容器２と図示しない搬送室との間には、ゲートバルブＧが配置されている。ゲートバルブＧは、搬入出口１２ａを開閉する機能を有している。ゲートバルブＧは、閉状態で処理容器２を気密にシールすると共に、開状態で処理容器２と図示しない搬送室との間でウエハＷの移送を可能にする。 The processing container 2 has a plate-like ceiling part 11 and a bottom part 13, and a side wall part 12 that connects the ceiling part 11 and the bottom part 13. The ceiling part 11 has a plurality of openings. The side wall portion 12 has a loading / unloading port 12 a for loading / unloading the wafer W to / from a transfer chamber (not shown) adjacent to the processing container 2. A gate valve G is disposed between the processing container 2 and a transfer chamber (not shown). The gate valve G has a function of opening and closing the loading / unloading port 12a. The gate valve G hermetically seals the processing container 2 in the closed state, and enables the transfer of the wafer W between the processing container 2 and a transfer chamber (not shown) in the open state.
　底部１３は、複数（図１では２つ）の排気口１３ａを有している。プラズマ処理装置１は、更に、排気口１３ａと排気装置４とを接続する排気管１４を備えている。排気装置４は、図示は省略するが、ＡＰＣバルブと、処理容器２の内部空間を所定の真空度まで高速に減圧することが可能な高速真空ポンプとを有している。このような高速真空ポンプとしては、例えばターボ分子ポンプ等がある。排気装置４の高速真空ポンプを作動させることによって、処理容器２は、その内部空間が所定の真空度、例えば０．１３３Ｐａまで減圧される。 The bottom 13 has a plurality (two in FIG. 1) of exhaust ports 13a. The plasma processing apparatus 1 further includes an exhaust pipe 14 that connects the exhaust port 13 a and the exhaust apparatus 4. Although not shown, the exhaust device 4 includes an APC valve and a high-speed vacuum pump that can depressurize the internal space of the processing vessel 2 to a predetermined vacuum level at high speed. Examples of such a high-speed vacuum pump include a turbo molecular pump. By operating the high-speed vacuum pump of the exhaust device 4, the internal space of the processing container 2 is depressurized to a predetermined degree of vacuum, for example, 0.133 Pa.
　プラズマ処理装置１は、更に、処理容器２内において載置台２１を支持する支持部材２２と、支持部材２２と処理容器２の底部１３との間に設けられた絶縁材料よりなる絶縁部材２３とを備えている。載置台２１は、被処理体であるウエハＷを水平に載置するためのものである。支持部材２２は、底部１３の中央から処理容器２の内部空間に向かって延びる円筒状の形状を有している。載置台２１および支持部材２２は、例えばＡｌＮ等によって形成されている。 The plasma processing apparatus 1 further includes a support member 22 that supports the mounting table 21 in the processing container 2 and an insulating member 23 made of an insulating material provided between the support member 22 and the bottom portion 13 of the processing container 2. I have. The mounting table 21 is used for horizontally mounting the wafer W, which is an object to be processed. The support member 22 has a cylindrical shape extending from the center of the bottom portion 13 toward the internal space of the processing container 2. The mounting table 21 and the support member 22 are made of, for example, AlN.
　プラズマ処理装置１は、更に、載置台２１に高周波電力を供給する高周波バイアス電源２５と、載置台２１と高周波バイアス電源２５との間に設けられた整合器２４とを備えている。高周波バイアス電源２５は、ウエハＷにイオンを引き込むために、載置台２１に高周波電力を供給する。 The plasma processing apparatus 1 further includes a high frequency bias power source 25 that supplies high frequency power to the mounting table 21 and a matching unit 24 provided between the mounting table 21 and the high frequency bias power source 25. The high frequency bias power supply 25 supplies high frequency power to the mounting table 21 in order to attract ions to the wafer W.
　図示しないが、プラズマ処理装置１は、更に、載置台２１を加熱または冷却する温度制御機構を備えている。温度制御機構は、例えば、ウエハＷの温度を、２５℃（室温）以上９００℃以下の範囲内で制御する。また、載置台２１は、載置面２１ａに対して突没可能に設けられた複数の支持ピンを有している。複数の支持ピンは、任意の昇降機構により上下に変位し、上昇位置において、図示しない搬送室との間でウエハＷの受け渡しを行うことができるように構成されている。 Although not shown, the plasma processing apparatus 1 further includes a temperature control mechanism for heating or cooling the mounting table 21. For example, the temperature control mechanism controls the temperature of the wafer W within a range of 25 ° C. (room temperature) to 900 ° C. The mounting table 21 has a plurality of support pins provided so as to be able to project and retract with respect to the mounting surface 21a. The plurality of support pins are configured to be displaced up and down by an arbitrary lifting mechanism so that the wafer W can be transferred to and from a transfer chamber (not shown) at the raised position.
　プラズマ処理装置１は、更に、処理容器２の天井部１１に設けられたガス導入部１５を備えている。ガス導入部１５は、円筒形状をなす複数のノズル１６を有している。ノズル１６は、その下面に形成されたガス孔１６ａを有している。ノズル１６の配置については、後で説明する。 The plasma processing apparatus 1 further includes a gas introduction part 15 provided in the ceiling part 11 of the processing container 2. The gas introduction part 15 has a plurality of nozzles 16 having a cylindrical shape. The nozzle 16 has a gas hole 16a formed on the lower surface thereof. The arrangement of the nozzles 16 will be described later.
　ガス供給機構３は、ガス供給源３１を含むガス供給装置３ａと、ガス供給源３１とガス導入部１５とを接続する配管３２とを有している。なお、図１では、１つのガス供給源３１を図示しているが、ガス供給装置３ａは、使用されるガスの種類に応じて複数のガス供給源を含んでいてもよい。 The gas supply mechanism 3 includes a gas supply device 3 a including a gas supply source 31, and a pipe 32 that connects the gas supply source 31 and the gas introduction unit 15. In FIG. 1, one gas supply source 31 is illustrated, but the gas supply device 3 a may include a plurality of gas supply sources according to the type of gas used.
　ガス供給源３１は、例えば、プラズマ生成用の希ガスや、酸化処理や窒化処理に使用される処理ガス等のガス供給源として用いられる。なお、プラズマ生成用の希ガスとしては、例えば、Ａｒ、Ｋｒ、Ｘｅ、Ｈｅ等が使用される。酸化処理に使用される処理ガスとしては、例えば、酸素ガス、オゾンガス等の酸化性ガスが使用される。窒化処理に使用される処理ガスとしては、例えば、窒素ガス、ＮＨ３ガス等が使用される。なお、希ガスは酸化処理用の処理ガスや、窒化処理用の処理ガスと共に使用される場合もある。 The gas supply source 31 is used as a gas supply source of, for example, a rare gas for plasma generation or a processing gas used for oxidation treatment or nitridation treatment. For example, Ar, Kr, Xe, He, or the like is used as a rare gas for generating plasma. As the processing gas used for the oxidation treatment, for example, an oxidizing gas such as oxygen gas or ozone gas is used. As the processing gas used for the nitriding treatment, for example, nitrogen gas, NH 3 gas or the like is used. The rare gas may be used together with a processing gas for oxidation treatment or a processing gas for nitridation treatment.
　図示しないが、ガス供給装置３ａは、更に、配管３２の途中に設けられたマスフローコントローラおよび開閉バルブを含んでいる。処理容器２内に供給されるガスの種類や、これらのガスの流量等は、マスフローコントローラおよび開閉バルブによって制御される。 Although not shown, the gas supply device 3a further includes a mass flow controller and an opening / closing valve provided in the middle of the pipe 32. The types of gases supplied into the processing container 2 and the flow rates of these gases are controlled by a mass flow controller and an opening / closing valve.
　プラズマ処理装置１の各構成部は、それぞれ制御部８に接続されて、制御部８によって制御される。制御部８は、典型的にはコンピュータである。図２に示した例では、制御部８は、ＣＰＵを備えたプロセスコントローラ８１と、このプロセスコントローラ８１に接続されたユーザーインターフェース８２および記憶部８３とを備えている。 Each component of the plasma processing apparatus 1 is connected to the control unit 8 and controlled by the control unit 8. The control unit 8 is typically a computer. In the example illustrated in FIG. 2, the control unit 8 includes a process controller 81 including a CPU, and a user interface 82 and a storage unit 83 connected to the process controller 81.
　プロセスコントローラ８１は、プラズマ処理装置１において、例えば温度、圧力、ガス流量、バイアス印加用の高周波電力、マイクロ波出力等のプロセス条件に関係する各構成部（例えば、高周波バイアス電源２５、ガス供給装置３ａ、排気装置４、マイクロ波導入装置５等）を統括して制御する制御手段である。 In the plasma processing apparatus 1, the process controller 81 is a component related to process conditions such as temperature, pressure, gas flow rate, high frequency power for bias application, microwave output, and the like (for example, high frequency bias power supply 25, gas supply device). 3a, the exhaust device 4, the microwave introduction device 5 and the like).
　ユーザーインターフェース８２は、工程管理者がプラズマ処理装置１を管理するためにコマンドの入力操作等を行うキーボードやタッチパネル、プラズマ処理装置１の稼働状況を可視化して表示するディスプレイ等を有している。 The user interface 82 includes a keyboard and a touch panel on which a process manager manages command input in order to manage the plasma processing apparatus 1, a display that visualizes and displays the operating status of the plasma processing apparatus 1, and the like.
　記憶部８３には、プラズマ処理装置１で実行される各種処理をプロセスコントローラ８１の制御によって実現するための制御プログラム（ソフトウエア）や、処理条件データ等が記録されたレシピ等が保存されている。プロセスコントローラ８１は、ユーザーインターフェース８２からの指示等、必要に応じて、任意の制御プログラムやレシピを記憶部８３から呼び出して実行する。これにより、プロセスコントローラ８１による制御下で、プラズマ処理装置１の処理容器２内において所望の処理が行われる。 The storage unit 83 stores a control program (software) for realizing various processes executed by the plasma processing apparatus 1 under the control of the process controller 81, a recipe in which processing condition data, and the like are recorded. . The process controller 81 calls and executes an arbitrary control program or recipe from the storage unit 83 as necessary, such as an instruction from the user interface 82. Thus, a desired process is performed in the processing container 2 of the plasma processing apparatus 1 under the control of the process controller 81.
　上記の制御プログラムおよびレシピは、例えば、ＣＤ－ＲＯＭ、ハードディスク、フレキシブルディスク、フラッシュメモリ、ＤＶＤ、ブルーレイディスク等のコンピュータ読み取り可能な記憶媒体に格納された状態のものを利用することができる。また、上記のレシピは、他の装置から、例えば専用回線を介して随時伝送させてオンラインで利用することも可能である。 The control program and recipe described above can be stored in a computer-readable storage medium such as a CD-ROM, hard disk, flexible disk, flash memory, DVD, or Blu-ray disk. Also, the above recipe can be transmitted from other devices as needed via, for example, a dedicated line and used online.
　次に、図１、図３ないし図６を参照して、マイクロ波導入装置５の構成について詳しく説明する。図３は、マイクロ波導入装置５の構成を示す説明図である。図４は、図３に示したマイクロ波導入機構を示す断面図である。図５は、図４に示したマイクロ波導入機構のアンテナ部を示す斜視図である。図６は、図４に示したマイクロ波導入機構の平面アンテナを示す平面図である。 Next, the configuration of the microwave introduction device 5 will be described in detail with reference to FIGS. 1 and 3 to 6. FIG. 3 is an explanatory diagram showing the configuration of the microwave introduction device 5. FIG. 4 is a cross-sectional view showing the microwave introduction mechanism shown in FIG. FIG. 5 is a perspective view showing an antenna portion of the microwave introduction mechanism shown in FIG. FIG. 6 is a plan view showing a planar antenna of the microwave introduction mechanism shown in FIG.
　前述のように、マイクロ波導入装置５は、処理容器２の上部に設けられ、処理容器２内に電磁波（マイクロ波）を導入してプラズマを生成するプラズマ生成手段として機能する。図１および図３に示したように、マイクロ波導入装置５は、処理容器２の上部に配置され、複数の開口部を有する導電性部材である天井部１１と、マイクロ波を生成すると共に、マイクロ波を複数の経路に分配して出力するマイクロ波出力部５０と、マイクロ波出力部５０から出力されたマイクロ波を処理容器２に導入するアンテナユニット６０とを有している。本実施の形態では、処理容器２の天井部１１は、マイクロ波導入装置５の導電性部材を兼ねている。 As described above, the microwave introduction device 5 is provided on the upper portion of the processing container 2 and functions as a plasma generating means for introducing an electromagnetic wave (microwave) into the processing container 2 to generate plasma. As shown in FIG. 1 and FIG. 3, the microwave introduction device 5 is disposed on the upper portion of the processing container 2 and generates a microwave, and a ceiling portion 11 that is a conductive member having a plurality of openings, A microwave output unit 50 that distributes and outputs the microwaves to a plurality of paths, and an antenna unit 60 that introduces the microwaves output from the microwave output unit 50 into the processing container 2 are provided. In the present embodiment, the ceiling portion 11 of the processing container 2 also serves as the conductive member of the microwave introduction device 5.
　マイクロ波出力部５０は、電源部５１と、マイクロ波発振器５２と、マイクロ波発振器５２によって発振されたマイクロ波を増幅するアンプ５３と、アンプ５３によって増幅されたマイクロ波を複数の経路に分配する分配器５４とを有している。マイクロ波発振器５２は、所定の周波数（例えば、８６０ＭＨｚ）でマイクロ波を発振（例えば、ＰＬＬ発振）させる。なお、マイクロ波の周波数は、８６０ＭＨｚに限らず、２．４５ＧＨｚ、８．３５ＧＨｚ、５．８ＧＨｚ、１．９８ＧＨｚ等であってもよい。分配器５４は、入力側と出力側のインピーダンスを整合させながらマイクロ波を分配する。 The microwave output unit 50 distributes the microwave amplified by the power supply unit 51, the microwave oscillator 52, the amplifier 53 that amplifies the microwave oscillated by the microwave oscillator 52, and the microwave amplified by the amplifier 53 to a plurality of paths. And a distributor 54. The microwave oscillator 52 oscillates microwaves (for example, PLL oscillation) at a predetermined frequency (for example, 860 MHz). The microwave frequency is not limited to 860 MHz, and may be 2.45 GHz, 8.35 GHz, 5.8 GHz, 1.98 GHz, or the like. The distributor 54 distributes the microwave while matching the impedances of the input side and the output side.
　アンテナユニット６０は、複数のアンテナモジュール６１を含んでいる。複数のアンテナモジュール６１は、それぞれ、分配器５４によって分配されたマイクロ波を処理容器２内に導入する。本実施の形態では、複数のアンテナモジュール６１の構成は全て同一である。各アンテナモジュール６１は、分配されたマイクロ波を主に増幅して出力するアンプ部６２と、アンプ部６２から出力されたマイクロ波を処理容器２内に導入するマイクロ波導入機構６３とを有している。 The antenna unit 60 includes a plurality of antenna modules 61. Each of the plurality of antenna modules 61 introduces the microwave distributed by the distributor 54 into the processing container 2. In the present embodiment, the configurations of the plurality of antenna modules 61 are all the same. Each antenna module 61 includes an amplifier unit 62 that mainly amplifies and outputs the distributed microwave, and a microwave introduction mechanism 63 that introduces the microwave output from the amplifier unit 62 into the processing container 2. ing.
　アンプ部６２は、マイクロ波の位相を変化させる位相器６２Ａと、メインアンプ６２Ｃに入力されるマイクロ波の電力レベルを調整する可変ゲインアンプ６２Ｂと、ソリッドステートアンプとして構成されたメインアンプ６２Ｃと、後述するマイクロ波導入機構６３のアンテナ部で反射されてメインアンプ６２Ｃに向かう反射マイクロ波を分離するアイソレータ６２Ｄとを含んでいる。 The amplifier unit 62 includes a phase shifter 62A that changes the phase of the microwave, a variable gain amplifier 62B that adjusts the power level of the microwave input to the main amplifier 62C, a main amplifier 62C configured as a solid state amplifier, It includes an isolator 62D that separates reflected microwaves that are reflected by an antenna portion of a microwave introduction mechanism 63, which will be described later, and travel toward the main amplifier 62C.
　位相器６２Ａは、マイクロ波の位相を変化させて、マイクロ波の放射特性を変化させることができるように構成されている。位相器６２Ａは、例えば、アンテナモジュール６１毎にマイクロ波の位相を調整することによって、マイクロ波の指向性を制御してプラズマの分布を変化させることに用いられる。なお、このような放射特性の調整を行わない場合には、位相器６２Ａを設けなくてもよい。 The phase shifter 62A is configured to change the microwave radiation characteristic by changing the phase of the microwave. The phase shifter 62A is used to change the plasma distribution by controlling the directivity of the microwave by adjusting the phase of the microwave for each antenna module 61, for example. If such adjustment of the radiation characteristics is not performed, the phase shifter 62A may not be provided.
　可変ゲインアンプ６２Ｂは、個々のアンテナモジュール６１のばらつきの調整や、プラズマ強度の調整のために用いられる。例えば、可変ゲインアンプ６２Ｂをアンテナモジュール６１毎に変化させることによって、処理容器２内全体のプラズマの分布を調整することができる。 The variable gain amplifier 62B is used for adjusting variations of individual antenna modules 61 and adjusting plasma intensity. For example, by changing the variable gain amplifier 62B for each antenna module 61, the plasma distribution in the entire processing container 2 can be adjusted.
　図示しないが、メインアンプ６２Ｃは、例えば、入力整合回路、半導体増幅素子、出力整合回路および高Ｑ共振回路を含んでいる。半導体増幅素子としては、例えば、Ｅ級動作が可能なＧａＡｓＨＥＭＴ、ＧａＮＨＥＭＴ、ＬＤ（Laterally Diffused）－ＭＯＳが用いられる。 Although not shown, the main amplifier 62C includes, for example, an input matching circuit, a semiconductor amplifying element, an output matching circuit, and a high Q resonance circuit. As the semiconductor amplifying element, for example, GaAs HEMT, GaN HEMT, and LD (Laterally Diffused) -MOS capable of class E operation are used.
　アイソレータ６２Ｄは、サーキュレータとダミーロード（同軸終端器）とを有している。サーキュレータは、後述するマイクロ波導入機構６３のアンテナ部で反射された反射マイクロ波をダミーロードへ導くものである。ダミーロードは、サーキュレータによって導かれた反射マイクロ波を熱に変換するものである。なお、前述のように、本実施の形態では、複数のアンテナモジュール６１が設けられており、複数のアンテナモジュール６１の各々のマイクロ波導入機構６３によって処理容器２内に複数のマイクロ波を導入できる。そのため、個々のアイソレータ６２Ｄは小型のものでもよく、アイソレータ６２Ｄをメインアンプ６２Ｃに隣接して設けることができる。 The isolator 62D has a circulator and a dummy load (coaxial terminator). The circulator guides the reflected microwave reflected by the antenna portion of the microwave introduction mechanism 63 described later to the dummy load. The dummy load converts the reflected microwave guided by the circulator into heat. As described above, in the present embodiment, a plurality of antenna modules 61 are provided, and a plurality of microwaves can be introduced into the processing container 2 by the respective microwave introduction mechanisms 63 of the plurality of antenna modules 61. . Therefore, each isolator 62D may be small, and the isolator 62D can be provided adjacent to the main amplifier 62C.
　図１に示したように、複数のマイクロ波導入機構６３は、天井部１１に設けられている。図４に示したように、マイクロ波導入機構６３は、インピーダンスを整合させるチューナ６４と、増幅されたマイクロ波を処理容器２内に放射するアンテナ部６５と、金属材料よりなり、図４における上下方向に延びる円筒状の形状を有する本体容器６６と、本体容器６６内において本体容器６６が延びる方向と同じ方向に延びる内側導体６７とを有している。本体容器６６および内側導体６７は、同軸管を構成している。本体容器６６は、この同軸管の外側導体を構成している。内側導体６７は、棒状または筒状の形状を有している。本体容器６６の内周面と内側導体６７の外周面との間の空間は、マイクロ波伝送路６８を形成する。 As shown in FIG. 1, the plurality of microwave introduction mechanisms 63 are provided on the ceiling portion 11. As shown in FIG. 4, the microwave introduction mechanism 63 includes a tuner 64 that matches impedance, an antenna unit 65 that radiates the amplified microwave into the processing container 2, and a metal material. A main body container 66 having a cylindrical shape extending in the direction, and an inner conductor 67 extending in the same direction as the main container container 66 extends in the main body container 66. The main body container 66 and the inner conductor 67 constitute a coaxial tube. The main body container 66 constitutes the outer conductor of this coaxial tube. The inner conductor 67 has a rod shape or a cylindrical shape. A space between the inner peripheral surface of the main body container 66 and the outer peripheral surface of the inner conductor 67 forms a microwave transmission path 68.
　図示しないが、アンテナモジュール６１は、更に、本体容器６６の基端側（上端側）に設けられた給電変換部を有している。給電変換部は、同軸ケーブルを介してメインアンプ６２Ｃに接続されている。アイソレータ６２Ｄは、同軸ケーブルの途中に設けられている。 Although not shown, the antenna module 61 further includes a power feeding conversion unit provided on the base end side (upper end side) of the main body container 66. The power feeding conversion unit is connected to the main amplifier 62C via a coaxial cable. The isolator 62D is provided in the middle of the coaxial cable.
　アンテナ部６５は、本体容器６６における給電変換部とは反対側に設けられている。後で説明するように、本体容器６６におけるアンテナ部６５よりも基端側の部分は、チューナ６４によるインピーダンス調整範囲となっている。 The antenna unit 65 is provided on the opposite side of the main body container 66 from the power conversion unit. As will be described later, a portion of the main body container 66 closer to the base end than the antenna portion 65 is in an impedance adjustment range by the tuner 64.
　図４および図５に示したように、アンテナ部６５は、内側導体６７の下端部に接続された平面アンテナ７１と、平面アンテナ７１の上面側に配置されたマイクロ波遅波材７２と、平面アンテナ７１の下面側に配置されたマイクロ波透過板７３とを有している。マイクロ波透過板７３の下面は、処理容器２の内部空間に露出している。マイクロ波透過板７３は、本体容器６６を介して、マイクロ波導入装置５の導電性部材である天井部１１の開口部に嵌合している。マイクロ波透過板７３は、本発明におけるマイクロ波透過窓に対応する。 As shown in FIGS. 4 and 5, the antenna unit 65 includes a planar antenna 71 connected to the lower end of the inner conductor 67, a microwave slow wave material 72 disposed on the upper surface side of the planar antenna 71, and a planar surface. And a microwave transmission plate 73 disposed on the lower surface side of the antenna 71. The lower surface of the microwave transmission plate 73 is exposed in the internal space of the processing container 2. The microwave transmission plate 73 is fitted into the opening of the ceiling portion 11 that is a conductive member of the microwave introduction device 5 through the main body container 66. The microwave transmission plate 73 corresponds to the microwave transmission window in the present invention.
　平面アンテナ７１は、円板形状を有している。また、平面アンテナ７１は、平面アンテナ７１を貫通するように形成されたスロット７１ａを有している。図５および図６に示した例では、４つのスロット７１ａが設けられており、各スロット７１ａは、４つに均等に分割された円弧形状を有している。なお、スロット７１ａの数は、４つに限らず、５つ以上であってもよいし、１つ以上３つ以下であってもよい。 The planar antenna 71 has a disc shape. The planar antenna 71 has a slot 71 a formed so as to penetrate the planar antenna 71. In the example shown in FIGS. 5 and 6, four slots 71 a are provided, and each slot 71 a has an arc shape that is equally divided into four. The number of slots 71a is not limited to four, but may be five or more, or may be one or more and three or less.
　マイクロ波遅波材７２は、真空よりも大きい誘電率を有する材料によって形成されている。マイクロ波遅波材７２を形成する材料としては、例えば、石英、セラミックス、ポリテトラフルオロエチレン樹脂等のフッ素系樹脂、ポリイミド樹脂等を用いることができる。マイクロ波は、真空中ではその波長が長くなる。マイクロ波遅波材７２は、マイクロ波の波長を短くしてプラズマを調整する機能を有している。また、マイクロ波の位相は、マイクロ波遅波材７２の厚みによって変化する。そのため、マイクロ波遅波材７２の厚みによってマイクロ波の位相を調整することにより、平面アンテナ７１が定在波の腹の位置になるように調整することができる。これにより、平面アンテナ７１における反射波を抑制することができると共に、平面アンテナ７１から放射されるマイクロ波の放射エネルギーを大きくすることができる。つまり、これにより、マイクロ波のパワーを効率よく処理容器２内に導入することができる。 The microwave slow wave material 72 is formed of a material having a dielectric constant larger than that of a vacuum. As a material for forming the microwave slow wave material 72, for example, fluororesin such as quartz, ceramics, polytetrafluoroethylene resin, polyimide resin, or the like can be used. Microwaves have a longer wavelength in vacuum. The microwave slow wave material 72 has a function of adjusting the plasma by shortening the wavelength of the microwave. Further, the phase of the microwave varies depending on the thickness of the microwave slow wave material 72. Therefore, by adjusting the phase of the microwave according to the thickness of the microwave slow wave material 72, the planar antenna 71 can be adjusted to be at the antinode position of the standing wave. Thereby, while being able to suppress the reflected wave in the planar antenna 71, the radiation energy of the microwave radiated | emitted from the planar antenna 71 can be enlarged. In other words, this allows microwave power to be efficiently introduced into the processing container 2.
　マイクロ波透過板７３は、誘電体材料によって形成されている。マイクロ波透過板７３を形成する誘電体材料としては、例えば石英やセラミックス等が用いられる。マイクロ波透過板７３は、マイクロ波をＴＥモードで効率的に放射することができるような形状をなしている。図５に示した例では、マイクロ波透過板７３は、直方体形状を有している。なお、マイクロ波透過板７３の形状は、直方体形状に限らず、例えば円柱形状、五角形柱形状、六角形柱形状、八角形柱形状であってもよい。 The microwave transmission plate 73 is made of a dielectric material. As a dielectric material for forming the microwave transmission plate 73, for example, quartz or ceramics is used. The microwave transmission plate 73 has a shape capable of efficiently radiating microwaves in the TE mode. In the example shown in FIG. 5, the microwave transmission plate 73 has a rectangular parallelepiped shape. The shape of the microwave transmission plate 73 is not limited to a rectangular parallelepiped shape, and may be, for example, a cylindrical shape, a pentagonal column shape, a hexagonal column shape, or an octagonal column shape.
　上記のように構成されたマイクロ波導入機構６３では、メインアンプ６２Ｃで増幅されたマイクロ波は、本体容器６６の内周面と内側導体６７の外周面との間（マイクロ波伝送路６８）を通って平面アンテナ７１に達し、平面アンテナ７１のスロット７１ａからマイクロ波透過板７３を透過して処理容器２の内部空間に放射される。 In the microwave introduction mechanism 63 configured as described above, the microwave amplified by the main amplifier 62C passes between the inner peripheral surface of the main body container 66 and the outer peripheral surface of the inner conductor 67 (microwave transmission path 68). It passes through the planar antenna 71, passes through the microwave transmitting plate 73 from the slot 71 a of the planar antenna 71, and is radiated to the internal space of the processing container 2.
　チューナ６４は、スラグチューナを構成している。具体的には、図４に示したように、チューナ６４は、本体容器６６のアンテナ部６５よりも基端部側（上端部側）の部分に配置された２つのスラグ７４Ａ，７４Ｂと、２つのスラグ７４Ａ，７４Ｂを動作させるアクチュエータ７５と、このアクチュエータ７５を制御するチューナコントローラ７６とを有している。 The tuner 64 constitutes a slag tuner. Specifically, as shown in FIG. 4, the tuner 64 includes two slugs 74 </ b> A and 74 </ b> B disposed on the base end side (upper end side) of the antenna body 65 of the main body container 66, and 2 An actuator 75 for operating the two slugs 74A and 74B and a tuner controller 76 for controlling the actuator 75 are provided.
　スラグ７４Ａ，７４Ｂは、板状且つ環状の形状を有し、本体容器６６の内周面と内側導体６７の外周面との間に配置されている。また、スラグ７４Ａ，７４Ｂは、誘電体材料によって形成されている。スラグ７４Ａ，７４Ｂを形成する誘電体材料としては、例えば、比誘電率が１０の高純度アルミナを用いることができる。高純度アルミナは、通常、スラグを形成する材料として用いられている石英（比誘電率３．８８）やテフロン（登録商標）（比誘電率２．０３）よりも比誘電率が大きいため、スラグ７４Ａ，７４Ｂの厚みを小さくすることができる。また、高純度アルミナは、石英やテフロン（登録商標）に比べて、誘電正接（ｔａｎδ）が小さく、マイクロ波の損失を小さくすることができるという特徴を有している。高純度アルミナは、更に、歪みが小さいという特徴と、熱に強いという特徴も有している。高純度アルミナとしては、純度９９．９％以上のアルミナ焼結体であることが好ましい。また、高純度アルミナとして、単結晶アルミナ（サファイア）を用いてもよい。 The slugs 74 </ b> A and 74 </ b> B have a plate shape and an annular shape, and are disposed between the inner peripheral surface of the main body container 66 and the outer peripheral surface of the inner conductor 67. The slugs 74A and 74B are made of a dielectric material. As a dielectric material for forming the slags 74A and 74B, for example, high-purity alumina having a relative dielectric constant of 10 can be used. High-purity alumina usually has a relative dielectric constant larger than that of quartz (relative dielectric constant 3.88) or Teflon (registered trademark) (relative dielectric constant 2.03), which is used as a material for forming slag. The thickness of 74A, 74B can be made small. Further, high-purity alumina has a feature that the dielectric loss tangent (tan δ) is smaller than that of quartz or Teflon (registered trademark), and the loss of microwaves can be reduced. High-purity alumina further has a feature of low distortion and a feature of being resistant to heat. The high-purity alumina is preferably an alumina sintered body having a purity of 99.9% or more. Further, single crystal alumina (sapphire) may be used as high purity alumina.
　チューナ６４は、チューナコントローラ７６からの指令に基づいて、アクチュエータ７５によって、スラグ７４Ａ，７４Ｂを上下方向に移動させる。これにより、チューナ６４は、インピーダンスを調整する。例えば、チューナコントローラ７６は、終端部のインピーダンスが５０Ωになるように、スラグ７４Ａ，７４Ｂの位置を調整する。 The tuner 64 moves the slugs 74A and 74B in the vertical direction by the actuator 75 based on a command from the tuner controller 76. Thereby, the tuner 64 adjusts the impedance. For example, the tuner controller 76 adjusts the positions of the slugs 74A and 74B so that the terminal impedance is 50Ω.
　本実施の形態では、メインアンプ６２Ｃ、チューナ６４および平面アンテナ７１は、互いに近接して配置されている。特に、チューナ６４および平面アンテナ７１は、集中定数回路を構成し、且つ共振器として機能する。平面アンテナ７１の取り付け部分には、インピーダンス不整合が存在する。本実施の形態では、チューナ６４によって、プラズマを含めて高精度でチューニングすることができ、平面アンテナ７１における反射の影響を解消することができる。また、チューナ６４によって、平面アンテナ７１に至るまでのインピーダンス不整合を高精度で解消することができ、実質的に不整合部分をプラズマ空間とすることができる。これにより、チューナ６４によって、高精度のプラズマ制御が可能になる。 In the present embodiment, the main amplifier 62C, the tuner 64, and the planar antenna 71 are arranged close to each other. In particular, the tuner 64 and the planar antenna 71 constitute a lumped constant circuit and function as a resonator. There is an impedance mismatch in the mounting portion of the planar antenna 71. In the present embodiment, the tuner 64 can be tuned with high accuracy including plasma, and the influence of reflection on the planar antenna 71 can be eliminated. Further, the tuner 64 can eliminate impedance mismatch up to the planar antenna 71 with high accuracy, and can substantially make the mismatched portion a plasma space. Thereby, the tuner 64 enables high-precision plasma control.
　次に、図７および図８を参照して、マイクロ波透過板７３の配置について説明する。図７は、図１に示した処理容器２の天井部１１の底面図である。図８は、本実施の形態における複数のマイクロ波透過板７３の配置を示す説明図である。なお、図７では、本体容器６６の図示を省略している。また、以下の説明では、マイクロ波透過板７３は、円柱形状を有するものとする。 Next, the arrangement of the microwave transmission plate 73 will be described with reference to FIGS. FIG. 7 is a bottom view of the ceiling portion 11 of the processing container 2 shown in FIG. FIG. 8 is an explanatory diagram showing the arrangement of a plurality of microwave transmission plates 73 in the present embodiment. In FIG. 7, the main body container 66 is not shown. In the following description, it is assumed that the microwave transmission plate 73 has a cylindrical shape.
　マイクロ波導入装置５は、複数のマイクロ波透過板７３を含んでいる。前述のように、マイクロ波透過板７３は、本発明におけるマイクロ波透過窓に対応する。複数のマイクロ波透過板７３は、マイクロ波導入装置５の導電性部材である天井部１１の複数の開口部に嵌合した状態で、載置台２１の載置面２１ａに平行な１つの仮想の平面上に配置されている。また、複数のマイクロ波透過板７３は、上記仮想の平面において、その中心点間の距離が互いに等しいか、ほぼ等しい３つのマイクロ波透過板７３を含んでいる。なお、中心点間の距離がほぼ等しいというのは、マイクロ波透過板７３の形状精度やアンテナモジュール６１（マイクロ波導入機構６３）の組み立て精度等の観点から、マイクロ波透過板７３の位置は、所望の位置からわずかにずれていてもよいことを意味する。 The microwave introduction device 5 includes a plurality of microwave transmission plates 73. As described above, the microwave transmission plate 73 corresponds to the microwave transmission window in the present invention. The plurality of microwave transmission plates 73 are fitted in a plurality of openings of the ceiling portion 11 that is a conductive member of the microwave introduction device 5, and are one virtual parallel to the mounting surface 21 a of the mounting table 21. It is arranged on a plane. Further, the plurality of microwave transmission plates 73 include three microwave transmission plates 73 whose distances between the center points are equal to or substantially equal to each other on the virtual plane. Note that the distances between the center points are substantially equal because the position of the microwave transmission plate 73 is determined from the viewpoint of the shape accuracy of the microwave transmission plate 73 and the assembly accuracy of the antenna module 61 (microwave introduction mechanism 63). It means that it may be slightly deviated from the desired position.
　本実施の形態では、複数のマイクロ波透過板７３は、六方最密配置になるように配置された７つのマイクロ波透過板７３からなるものである。具体的には、複数のマイクロ波透過板７３は、その中心点がそれぞれ正六角形の頂点に一致またはほぼ一致するように配置された６つのマイクロ波透過板７３Ａ～７３Ｆと、その中心点が正六角形の中心に一致またはほぼ一致するように配置された１つのマイクロ波透過板７３Ｇからなるものである。図８において、符号ＰＡ～ＰＧは、それぞれ、マイクロ波透過板７３Ａ～７３Ｇの中心点を示している。なお、頂点または中心点にほぼ一致するというのは、マイクロ波透過板７３の形状精度やアンテナモジュール６１（マイクロ波導入機構６３）の組み立て精度等の観点から、マイクロ波透過板７３の中心点は、上記の頂点または中心からわずかにずれていてもよいことを意味する。 In the present embodiment, the plurality of microwave transmission plates 73 are composed of seven microwave transmission plates 73 arranged so as to have a hexagonal close-packed arrangement. Specifically, each of the plurality of microwave transmission plates 73 has six microwave transmission plates 73A to 73F arranged so that the center points thereof coincide with or substantially coincide with the vertices of a regular hexagon, and the center points thereof are regular six. The microwave transmission plate 73G is arranged so as to coincide with or substantially coincide with the center of the square. In FIG. 8, symbols P A to P G indicate the center points of the microwave transmission plates 73A to 73G, respectively. It should be noted that substantially matching the vertex or center point means that the center point of the microwave transmitting plate 73 is from the viewpoint of the shape accuracy of the microwave transmitting plate 73 and the assembly accuracy of the antenna module 61 (microwave introducing mechanism 63). , Meaning that it may be slightly deviated from the above vertex or center.
　図７に示したように、マイクロ波透過板７３Ｇは、天井部１１における中央部分に配置されている。６つのマイクロ波透過板７３Ａ～７３Ｆは、マイクロ波透過板７３Ｇを囲むように、天井部１１の中央部分よりも外側に配置されている。従って、マイクロ波透過板７３Ｇは、本発明における中心マイクロ波透過窓に対応し、マイクロ波透過板７３Ａ～７３Ｆは、本発明における外側マイクロ波透過窓に対応する。なお、本実施の形態において、「天井部１１における中央部分」というのは、「天井部１１の平面形状における中央部分」を意味する。 As shown in FIG. 7, the microwave transmission plate 73 </ b> G is disposed in the central portion of the ceiling portion 11. The six microwave transmission plates 73A to 73F are arranged outside the central portion of the ceiling portion 11 so as to surround the microwave transmission plate 73G. Therefore, the microwave transmission plate 73G corresponds to the central microwave transmission window in the present invention, and the microwave transmission plates 73A to 73F correspond to the outer microwave transmission window in the present invention. In the present embodiment, “the central portion in the ceiling portion 11” means “the central portion in the planar shape of the ceiling portion 11”.
　マイクロ波透過板７３Ａ～７３Ｇは、以下の第１および第２の条件を満たしながら配置されている。第１の条件は、マイクロ波透過板７３Ａ～７３Ｇの中心点ＰＡ～ＰＧのうち、互いに隣接する３つの中心点を結ぶことによって平面状に６個の正三角形が形成されるというものである。第２の条件は、これら６個の正三角形によって仮想の正六角形が形成されるというものである。図８に示したように、マイクロ波透過板７３Ａ～７３Ｆの中心点ＰＡ～ＰＦを、マイクロ波透過板７３Ｇを囲むように結ぶと、上記の仮想の正六角形が形成される。 The microwave transmission plates 73A to 73G are arranged while satisfying the following first and second conditions. The first condition is that six equilateral triangles are formed in a planar shape by connecting three adjacent central points among the central points P A to P G of the microwave transmitting plates 73A to 73G. is there. The second condition is that a virtual regular hexagon is formed by these six regular triangles. As shown in FIG. 8, when the center points P A to P F of the microwave transmission plates 73A to 73F are connected so as to surround the microwave transmission plate 73G, the above-mentioned virtual regular hexagon is formed.
　なお、図８において、符号Ｗは、ウエハＷの平面形状を、複数のマイクロ波透過板７３が配置された仮想の平面に投影して形成された図形（以下、単にウエハＷの平面形状と記す。）を示している。図８に示した例では、ウエハＷの平面形状は円形である。本実施の形態では、マイクロ波透過板７３Ａ～７３Ｆの中心点ＰＡ～ＰＦの基準となる正六角形の外縁は、ウエハＷの平面形状を包含している。マイクロ波透過板７３Ｇの中心点ＰＧは、ウエハＷの平面形状（円）の中心点に一致またはほぼ一致している。マイクロ波透過板７３Ａ～７３Ｆの中心点ＰＡ～ＰＦは、ウエハＷの平面形状に対する同心円の円周上において、均等またはほぼ均等の間隔で配置されている。 In FIG. 8, symbol W denotes a figure formed by projecting the planar shape of the wafer W onto a virtual plane on which a plurality of microwave transmission plates 73 are arranged (hereinafter simply referred to as the planar shape of the wafer W). .). In the example shown in FIG. 8, the planar shape of the wafer W is circular. In the present embodiment, the regular hexagonal outer edge that serves as a reference for the center points P A to P F of the microwave transmission plates 73A to 73F includes the planar shape of the wafer W. The center point P G of the microwave transmitting plate 73G is consistent or nearly coincides with the central point of the planar shape of the wafer W (circles). The center points P A to P F of the microwave transmission plates 73A to 73F are arranged at equal or substantially equal intervals on the circumference of a concentric circle with respect to the planar shape of the wafer W.
　本実施の形態では、全てのマイクロ波透過板７３において、互いに隣接する任意の３つのマイクロ波透過板７３の中心点間の距離は、互いに等しいか、ほぼ等しくなる。以下、これについて、マイクロ波透過板７３Ａ，７３Ｂ，７３Ｇを例にとって説明する。図８に示したように、マイクロ波透過板７３Ａ，７３Ｂの中心点ＰＡ，ＰＢは、正六角形の隣接する２つの頂点に一致している。また、マイクロ波透過板７３Ｇの中心点ＰＧは、正六角形の中心点に一致している。図８に示したように、中心点ＰＡ，ＰＢ，ＰＧを結んで描いた図形は、正三角形になる。従って、中心点ＰＡ，ＰＢ，ＰＧ間の距離は互いに等しくなる。 In the present embodiment, in all the microwave transmission plates 73, the distances between the center points of arbitrary three microwave transmission plates 73 adjacent to each other are equal to or substantially equal to each other. Hereinafter, this will be described taking the microwave transmission plates 73A, 73B, and 73G as an example. As shown in FIG. 8, the center points P A and P B of the microwave transmission plates 73A and 73B coincide with two adjacent vertices of a regular hexagon. The center point P G of the microwave transmitting plate 73G coincides with the regular hexagon of the center point. As shown in FIG. 8, the figure drawn by connecting the center points P A , P B , and P G is an equilateral triangle. Accordingly, the center point P A, P B, the distance between P G are equal to each other.
　上記のマイクロ波透過板７３Ａ，７３Ｂ，７３Ｇについての説明は、互いに隣接する３つのマイクロ波透過板７３の組み合わせのいずれについても当てはまる。従って、本実施の形態では、全てのマイクロ波透過板７３において、互いに隣接する任意の３つのマイクロ波透過板７３の中心点間の距離は、互いに等しいか、ほぼ等しくなる。 The above description of the microwave transmission plates 73A, 73B, 73G is applicable to any combination of the three microwave transmission plates 73 adjacent to each other. Therefore, in the present embodiment, in all the microwave transmission plates 73, the distances between the center points of arbitrary three microwave transmission plates 73 adjacent to each other are equal to or substantially equal to each other.
　図４に示したように、マイクロ波導入機構６３は、マイクロ波透過板７３を含んだ一体構造をなしている。本実施の形態では、複数のマイクロ波導入機構６３は、７つのマイクロ波導入機構６３からなるものである。各マイクロ波導入機構６３は、図７および図８に示したマイクロ波透過板７３が配置された位置に対応して配置されている。また、図７に示したように、ガス導入部１５の複数のノズル１６は、マイクロ波透過板７３Ａ～７３Ｆとマイクロ波透過板７３Ｇとの間において、マイクロ波透過板７３Ｇの周囲を囲むように配置されている。 As shown in FIG. 4, the microwave introduction mechanism 63 has an integral structure including a microwave transmission plate 73. In the present embodiment, the plurality of microwave introduction mechanisms 63 includes seven microwave introduction mechanisms 63. Each microwave introduction mechanism 63 is arranged corresponding to the position where the microwave transmission plate 73 shown in FIGS. 7 and 8 is arranged. Further, as shown in FIG. 7, the plurality of nozzles 16 of the gas introduction unit 15 surround the microwave transmission plate 73G between the microwave transmission plates 73A to 73F and the microwave transmission plate 73G. Has been placed.
　次に、プラズマ処理装置１におけるプラズマ処理の手順の一例について説明する。ここでは、処理ガスとして酸素を含有するガスを使用して、ウエハＷの表面に対してプラズマ酸化処理を施す場合を例に挙げて、プラズマ処理の手順について説明する。まず、例えばユーザーインターフェース８２から、プラズマ処理装置１においてプラズマ酸化処理を行うように、プロセスコントローラ８１に指令が入力される。次に、プロセスコントローラ８１は、この指令を受けて、記憶部８３またはコンピュータ読み取り可能な記憶媒体に保存されたレシピを読み出す。次に、レシピに基づく条件によってプラズマ酸化処理が実行されるように、プロセスコントローラ８１からプラズマ処理装置１の各エンドデバイス（例えば、高周波バイアス電源２５、ガス供給装置３ａ、排気装置４、マイクロ波導入装置５等）に制御信号が送出される。 Next, an example of a plasma processing procedure in the plasma processing apparatus 1 will be described. Here, the procedure of the plasma processing will be described by taking as an example a case where the surface of the wafer W is subjected to plasma oxidation using a gas containing oxygen as the processing gas. First, for example, a command is input from the user interface 82 to the process controller 81 so as to perform plasma oxidation processing in the plasma processing apparatus 1. Next, the process controller 81 receives this command, and reads a recipe stored in the storage unit 83 or a computer-readable storage medium. Next, each end device of the plasma processing apparatus 1 (for example, the high frequency bias power supply 25, the gas supply apparatus 3a, the exhaust apparatus 4, and the microwave introduction is performed so that the plasma oxidation process is executed according to the conditions based on the recipe. A control signal is sent to the apparatus 5 or the like.
　次に、ゲートバルブＧが開状態にされて、図示しない搬送装置によって、ウエハＷが、ゲートバルブＧおよび搬入出口１２ａを通って処理容器２内に搬入される。ウエハＷは、載置台２１の載置面２１ａに載置される。次に、ゲートバルブＧが閉状態にされて、排気装置４によって、処理容器２内が減圧排気される。次に、ガス供給機構３によって、所定の流量の希ガスおよび酸素含有ガスが、ガス導入部１５を介して処理容器２内に導入される。処理容器２の内部空間は、排気量およびガス供給量を調整することによって、所定の圧力に調整される。 Next, the gate valve G is opened, and the wafer W is loaded into the processing container 2 through the gate valve G and the loading / unloading port 12a by a transfer device (not shown). The wafer W is placed on the placement surface 21 a of the placement table 21. Next, the gate valve G is closed, and the inside of the processing container 2 is evacuated by the exhaust device 4. Next, the gas supply mechanism 3 introduces a rare gas and an oxygen-containing gas at a predetermined flow rate into the processing container 2 through the gas introduction unit 15. The internal space of the processing container 2 is adjusted to a predetermined pressure by adjusting the exhaust amount and the gas supply amount.
　次に、マイクロ波出力部５０において、処理容器２内に導入するマイクロ波を発生させる。マイクロ波出力部５０の分配器５４から出力された複数のマイクロ波は、アンテナユニット６０の複数のアンテナモジュール６１に入力され、各アンテナモジュール６１によって、処理容器２内に導入される。各アンテナモジュール６１では、マイクロ波は、アンプ部６２およびマイクロ波導入機構６３を伝搬する。マイクロ波導入機構６３のアンテナ部６５に到達したマイクロ波は、平面アンテナ７１のスロット７１ａから、マイクロ波透過板７３を透過して、処理容器２内におけるウエハＷの上方の空間に放射される。このようにして、各アンテナモジュール６１から、それぞれ別々にマイクロ波が処理容器２内に導入される。 Next, the microwave to be introduced into the processing container 2 is generated in the microwave output unit 50. The plurality of microwaves output from the distributor 54 of the microwave output unit 50 are input to the plurality of antenna modules 61 of the antenna unit 60 and are introduced into the processing container 2 by each antenna module 61. In each antenna module 61, the microwave propagates through the amplifier unit 62 and the microwave introduction mechanism 63. The microwave that has reached the antenna unit 65 of the microwave introduction mechanism 63 passes through the microwave transmission plate 73 from the slot 71 a of the planar antenna 71 and is radiated to the space above the wafer W in the processing chamber 2. In this way, microwaves are individually introduced into the processing container 2 from the respective antenna modules 61.
　上記のように複数の部位から処理容器２内に導入されたマイクロ波は、それぞれ処理容器２内に電磁界を形成する。これにより、処理容器２内に導入された希ガスや酸素含有ガス等の処理ガスをプラズマ化する。そして、プラズマ中の活性種、例えばラジカルやイオンの作用によって、ウエハＷのシリコン表面が酸化されてシリコン酸化膜ＳｉＯ２の薄膜が形成される。 The microwaves introduced into the processing container 2 from a plurality of parts as described above form an electromagnetic field in the processing container 2 respectively. Thereby, the processing gas such as a rare gas or an oxygen-containing gas introduced into the processing container 2 is turned into plasma. Then, the silicon surface of the wafer W is oxidized by the action of active species in the plasma, such as radicals or ions, to form a silicon oxide film SiO 2 thin film.
　プロセスコントローラ８１からプラズマ処理装置１の各エンドデバイスにプラズマ処理を終了させる制御信号が送出されると、マイクロ波の発生が停止されると共に、希ガスおよび酸素含有ガスの供給が停止されて、ウエハＷに対するプラズマ処理が終了する。次に、ゲートバルブＧが開状態にされて、図示しない搬送装置によって、ウエハＷが搬出される。 When a control signal for terminating the plasma processing is sent from the process controller 81 to each end device of the plasma processing apparatus 1, the generation of microwaves is stopped and the supply of rare gas and oxygen-containing gas is stopped, and the wafer is stopped. The plasma processing for W ends. Next, the gate valve G is opened, and the wafer W is unloaded by a transfer device (not shown).
　なお、酸素含有ガスの代りに窒素含有ガスを使用することにより、ウエハＷに対して窒化処理を施し、シリコン窒化膜ＳｉＮの薄膜を形成することができる。 Note that by using a nitrogen-containing gas instead of the oxygen-containing gas, the wafer W can be nitrided to form a silicon nitride film SiN thin film.
　プラズマ処理装置１では、互いに隣接するマイクロ波透過板７３の中心点間距離が、互いに等しいかほぼ等しくなるように設定される。隣接する複数のマイクロ波透過板７３の中心点間距離が異なるように配置されていると、各マイクロ波透過板７３に基づくマイクロ波プラズマの密度分布が全て同一の場合、プラズマ密度に偏りが生じ、ウエハＷの面内での処理の均一性を保つことが困難になる。これに対し、プラズマ処理装置１では、互いに隣接するマイクロ波透過板７３の中心点間距離が、互いに等しいかほぼ等しくなるように設定されることから、マイクロ波プラズマの密度分布を均一化することが容易になる。このように、プラズマ処理装置１では、簡単な構成で、マイクロ波プラズマの密度分布を均一化することが可能になり、ウエハＷの面内での処理の均一性が得られる。 In the plasma processing apparatus 1, the distance between the center points of the microwave transmission plates 73 adjacent to each other is set to be equal to or approximately equal to each other. If the plurality of adjacent microwave transmission plates 73 are arranged so that the distances between their center points are different, the plasma density is biased when the density distribution of the microwave plasma based on each microwave transmission plate 73 is the same. It becomes difficult to maintain the uniformity of processing within the surface of the wafer W. On the other hand, in the plasma processing apparatus 1, the distance between the center points of the adjacent microwave transmission plates 73 is set to be equal to or substantially equal to each other, so that the density distribution of the microwave plasma is made uniform. Becomes easier. As described above, in the plasma processing apparatus 1, it is possible to make the density distribution of the microwave plasma uniform with a simple configuration, and the processing uniformity within the surface of the wafer W can be obtained.
　また、プラズマ処理装置１では、マイクロ波透過板７３Ｇは、天井部１１における中央部分に配置され、６つのマイクロ波透過板７３Ａ～７３Ｆは、マイクロ波透過板７３Ｇを囲むように、天井部１１の中央部分よりも外側に配置されている。これにより、プラズマ処理装置１では、広い領域にわたって、マイクロ波プラズマの密度分布を均一化することが可能になる。また、プラズマ処理装置１では、複数のアンテナモジュール６１の構成は全て同一である。これにより、プラズマ処理装置１では、各アンテナモジュール６１において同様のプラズマ発生条件を用いることができ、マイクロ波プラズマの密度分布の調整が容易になる。なお、正六角形の内側に対応する領域の下方におけるプラズマ密度は、正六角形の外側に対応する領域の下方におけるプラズマ密度よりも大きくなる。本実施の形態では、図８を参照して説明したように、マイクロ波透過板７３Ａ～７３Ｆの中心点の基準となる正六角形の外縁は、ウエハＷの平面形状を包含している。これにより、プラズマ処理装置１では、プラズマ密度が大きい領域にウエハＷを配置することができる。 Further, in the plasma processing apparatus 1, the microwave transmission plate 73G is disposed at the center portion of the ceiling portion 11, and the six microwave transmission plates 73A to 73F are arranged on the ceiling portion 11 so as to surround the microwave transmission plate 73G. It is arrange | positioned outside the center part. Thereby, in the plasma processing apparatus 1, it is possible to make the density distribution of the microwave plasma uniform over a wide area. In the plasma processing apparatus 1, the configuration of the plurality of antenna modules 61 is the same. Thereby, in the plasma processing apparatus 1, the same plasma generation conditions can be used in each antenna module 61, and the adjustment of the density distribution of the microwave plasma is facilitated. The plasma density below the region corresponding to the inside of the regular hexagon is larger than the plasma density below the region corresponding to the outside of the regular hexagon. In the present embodiment, as described with reference to FIG. 8, the outer edge of the regular hexagon serving as the reference of the center point of the microwave transmission plates 73A to 73F includes the planar shape of the wafer W. Thereby, in the plasma processing apparatus 1, the wafer W can be arrange | positioned to the area | region where a plasma density is large.
［第１の実施の形態のプラズマ処理方法］
　次に、プラズマ処理装置１を用いて行われる本発明の第１の実施の形態に係るプラズマ処理方法について説明する。本実施の形態のプラズマ処理方法は、プラズマ処理装置１の処理容器２内で複数のマイクロ波によりプラズマを生成させて被処理体であるウエハＷを処理し、例えばウエハＷの表面のシリコンを酸化してシリコン酸化膜を形成する。なお、本明細書において、複数のマイクロ波によりプラズマを着火させるときの複数のマイクロ波パワーの合計を「着火時総パワー」、前記プラズマでウエハＷを処理するときの複数のマイクロ波パワーの合計を「プロセス時総パワー」とする。また、１つのマイクロ波からプラズマを着火させるときのマイクロ波パワーを「着火時パワー」、１つのマイクロ波から生成したプラズマでウエハＷを処理するときのマイクロ波パワーを「プロセス時パワー」とする。 [Plasma Processing Method of First Embodiment]
Next, a plasma processing method according to the first embodiment of the present invention performed using the plasma processing apparatus 1 will be described. In the plasma processing method of the present embodiment, plasma is generated by a plurality of microwaves in the processing container 2 of the plasma processing apparatus 1 to process the wafer W, which is an object to be processed, and, for example, silicon on the surface of the wafer W is oxidized. Then, a silicon oxide film is formed. In this specification, the total of a plurality of microwave powers when the plasma is ignited by a plurality of microwaves is referred to as “total power during ignition”, and the total of a plurality of microwave powers when the wafer W is processed with the plasma. Is “total power during process”. Further, the microwave power when igniting plasma from one microwave is “power during ignition”, and the microwave power when processing the wafer W with plasma generated from one microwave is “process power”. .
　本実施の形態では、処理容器２内に複数のマイクロ波によりプラズマを生成させる複数マイクロ波方式のプラズマ処理装置１を用い、厚さ１ｎｍ（１０オングストローム）以下、好ましくは０．５ｎｍ以上１ｎｍ以下の範囲内の極薄膜を形成するために、低いマイクロ波パワーでプラズマ酸化処理を行う。具体的には、本実施の形態のプラズマ処理方法では、着火時総パワーを、ウエハＷの面積当たり１Ｗ／ｃｍ２以下、好ましくは０．８Ｗ／ｃｍ２以下、より好ましくは０．６Ｗ／ｃｍ２以下とする。例えば、３００ｍｍ径のウエハＷを被処理体とする場合、着火時総パワーを７００Ｗ以下、好ましくは５６０Ｗ以下、より好ましくは４２０Ｗ以下とする。 In the present embodiment, a plasma processing apparatus 1 of a plurality of microwaves that generates plasma by a plurality of microwaves in the processing container 2 is used, and the thickness is 1 nm (10 angstroms) or less, preferably 0.5 nm or more and 1 nm or less. In order to form an ultrathin film within the range, plasma oxidation is performed with low microwave power. Specifically, in the plasma processing method of the present embodiment, the total power during ignition, per area of the wafer W 1W / cm 2 or less, preferably 0.8 W / cm 2 or less, more preferably 0.6 W / cm 2 or less. For example, when a wafer W having a diameter of 300 mm is used as an object to be processed, the total power upon ignition is set to 700 W or less, preferably 560 W or less, more preferably 420 W or less.
　本実施の形態のプラズマ処理方法で、着火時総パワーを上記のように規定する理由は以下のとおりである。一般に、マイクロ波透過板７３が小径であるプラズマ処理装置１において、着火時総パワーは、プロセス時総パワーに比べて、２～３倍程度大きい値となる。従って、着火時総パワーがウエハＷの面積当たり１Ｗ／ｃｍ２以下であれば、プロセス時総パワーは概ねウエハＷの面積当たり１Ｗ／ｃｍ２以下となり、低パワーでのプラズマ処理が可能になる。 The reason why the total power at the time of ignition is specified as described above in the plasma processing method of the present embodiment is as follows. In general, in the plasma processing apparatus 1 in which the microwave transmission plate 73 has a small diameter, the total power during ignition is about 2 to 3 times larger than the total power during processing. Therefore, if the total power at the time of ignition is 1 W / cm 2 or less per area of the wafer W, the total power during the process is approximately 1 W / cm 2 or less per area of the wafer W, and plasma processing with low power becomes possible.
　これに対し、大径のマイクロ波透過板を用いる単一マイクロ波方式のプラズマ処理装置では、着火時パワーが１Ｗ／ｃｍ２以下では、プラズマの着火が困難であり、また、極力低いパワーで着火させる場合には、安定したプラズマを維持する観点からも、概してプロセス時パワーと着火時パワーがほぼ等しい値になる場合が多い。 In contrast, in a single microwave plasma processing apparatus using a large-diameter microwave transmission plate, it is difficult to ignite plasma when the power during ignition is 1 W / cm 2 or less, and ignition is performed with as low a power as possible. In order to maintain a stable plasma, the power during the process and the power during the ignition are generally almost equal in many cases.
　ここで、本実施の形態のプラズマ処理方法の特徴をより明確にするため、比較例のプラズマ処理方法に用いるプラズマ処理装置について説明する。図９は、処理容器内で一つのマイクロ波からプラズマを生成させる単一マイクロ波方式のプラズマ処理装置５０１の構成を模式的に示す断面図である。プラズマ処理装置５０１は、処理容器５０２、載置台５２１および支持部材５２２を備えている。処理容器５０２、載置台５２１および支持部材５２２の構成は、図１に示した処理容器２、載置台２１および支持部材２２の構成と同じである。 Here, in order to clarify the characteristics of the plasma processing method of the present embodiment, a plasma processing apparatus used for the plasma processing method of the comparative example will be described. FIG. 9 is a cross-sectional view schematically showing the configuration of a single microwave plasma processing apparatus 501 that generates plasma from one microwave in a processing container. The plasma processing apparatus 501 includes a processing container 502, a mounting table 521, and a support member 522. The configuration of the processing container 502, the mounting table 521, and the supporting member 522 is the same as the configuration of the processing container 2, the mounting table 21, and the supporting member 22 shown in FIG.
　プラズマ処理装置５０１は、図１および図３に示したマイクロ波導入装置５の代りに、マイクロ波導入装置５０５を備えている。マイクロ波導入装置５０５は、処理容器５０２の上部に設けられる。マイクロ波導入装置５０５としては、マイクロ波透過板５７３を１個だけ含む既知の構成のマイクロ波導入装置を用いることができる。マイクロ波透過板５７３は、例えば円板形状を有している。マイクロ波透過板５７３の平面形状の直径は、ウエハＷの直径よりも大きく、例えば４６０ｍｍである。 The plasma processing apparatus 501 includes a microwave introducing device 505 instead of the microwave introducing device 5 shown in FIGS. 1 and 3. The microwave introduction device 505 is provided on the upper portion of the processing container 502. As the microwave introduction device 505, a microwave introduction device having a known configuration including only one microwave transmission plate 573 can be used. The microwave transmission plate 573 has, for example, a disk shape. The diameter of the planar shape of the microwave transmission plate 573 is larger than the diameter of the wafer W, for example, 460 mm.
　プラズマ処理装置５０１におけるその他の構成は、プラズマ処理装置１と同じである。 Other configurations of the plasma processing apparatus 501 are the same as those of the plasma processing apparatus 1.
　プラズマ処理装置５０１では、マイクロ波透過板５７３の数が１個であることから、マイクロ波透過板５７３の平面形状をウエハＷの平面形状よりも大きくする必要がある。マイクロ波透過板５７３の面積が大きくなると、プラズマを安定的に着火および放電させるために必要なマイクロ波のパワーも大きくなる。例えば、マイクロ波透過板５７３が円板形状を有し、マイクロ波透過板５７３の平面形状の直径が約５００ｍｍの場合、プラズマを安定的に着火および放電させるために必要なマイクロ波のパワー（着火時パワー及びプロセス時パワー）の最小値は１０００Ｗである。 In the plasma processing apparatus 501, since the number of the microwave transmission plates 573 is one, the planar shape of the microwave transmission plates 573 needs to be larger than the planar shape of the wafer W. As the area of the microwave transmission plate 573 increases, the microwave power necessary to stably ignite and discharge the plasma also increases. For example, when the microwave transmission plate 573 has a disk shape and the diameter of the planar shape of the microwave transmission plate 573 is about 500 mm, the microwave power (ignition) required to stably ignite and discharge the plasma. The minimum value of (hour power and process power) is 1000 W.
　一方、プラズマ処理装置１では、複数のマイクロ波透過板７３が設けられることから、プラズマ処理装置５０１のマイクロ波透過板５７３に比べて、マイクロ波透過板７３の面積を小さくすることができる。なお、プラズマ処理装置１のマイクロ波透過板７３が円柱形状を有している場合、１つのマイクロ波透過板７３の平面形状の直径は、例えば９０ｍｍ以上２００ｍｍ以下の範囲内、好ましくは９０ｍｍ以上１５０ｍｍ以下の範囲内とすることができる。その結果、プラズマ処理装置１では、プラズマ処理装置５０１を用いる場合に比べて、プラズマを安定的に着火および放電維持させるために必要なマイクロ波のパワーを小さくすることができる。これにより、プラズマ処理装置１では、低パワーのマイクロ波によるプラズマ着火及び放電維持が可能になり、厚さ１ｎｍ以下の薄膜を、膜厚を制御しながら形成するプラズマ処理に適している。 On the other hand, since the plurality of microwave transmission plates 73 are provided in the plasma processing apparatus 1, the area of the microwave transmission plate 73 can be made smaller than that of the microwave transmission plate 573 of the plasma processing apparatus 501. When the microwave transmission plate 73 of the plasma processing apparatus 1 has a cylindrical shape, the diameter of the planar shape of one microwave transmission plate 73 is, for example, in the range of 90 mm to 200 mm, preferably 90 mm to 150 mm. It can be within the following range. As a result, the plasma processing apparatus 1 can reduce the microwave power necessary for stably igniting and maintaining discharge of the plasma as compared with the case where the plasma processing apparatus 501 is used. As a result, the plasma processing apparatus 1 can perform plasma ignition and discharge maintenance with a low-power microwave, and is suitable for plasma processing in which a thin film having a thickness of 1 nm or less is formed while controlling the film thickness.
＜プラズマ酸化処理の条件＞
　次に、プラズマ処理装置１を用いて、１ｎｍ以下の膜厚のシリコン酸化膜を形成するための主要な条件として、処理ガスの種類と流量、処理圧力、マイクロ波パワー、処理温度、酸化レート、処理時間、インピーダンス整合手順を挙げて詳細に説明する。なお、これらの条件は、制御部８の記憶部８３にレシピとして保存されている。そして、プロセスコントローラ８１がそのレシピを読み出してプラズマ処理装置１の各構成部へ制御信号を送出することにより、所望の条件でプラズマ酸化処理が行われる。 <Plasma oxidation conditions>
Next, the main conditions for forming a silicon oxide film having a thickness of 1 nm or less using the plasma processing apparatus 1 are as follows: type and flow rate of processing gas, processing pressure, microwave power, processing temperature, oxidation rate, The processing time and impedance matching procedure will be described in detail. Note that these conditions are stored as recipes in the storage unit 83 of the control unit 8. Then, the process controller 81 reads out the recipe and sends a control signal to each component of the plasma processing apparatus 1, whereby the plasma oxidation process is performed under desired conditions.
＜処理ガスの種類と流量＞
　プラズマ酸化処理の処理ガスとしては、プラズマ生成用の希ガスと酸素含有ガスを用いることが好ましい。希ガスとしては、例えば、Ａｒ、Ｋｒ、Ｘｅ、Ｈｅ等を使用することができる。酸素含有ガスとしては、例えば、Ｏ２ガス、オゾンガス等を使用することができる。これらの中でも、希ガスとしてはＡｒガスが、酸素含有ガスとしてはＯ２ガスが、それぞれ好ましい。処理容器２内における全処理ガスに対する酸素含有ガスの体積流量比率（酸素含有ガス流量／全処理ガス流量の百分率）は、酸化力を適度に調節して厚さ１ｎｍ以下の薄膜の形成を容易にする観点から、例えば０．１％以上５％以下の範囲内とすることが好ましく、０．５％以上３％以下の範囲内とすることがより好ましい。プラズマ酸化処理では、希ガスの流量は、例えば１００ｍＬ／ｍｉｎ（ｓｃｃｍ）以上１００００ｍＬ／ｍｉｎ（ｓｃｃｍ）以下の範囲内から、上記流量比になるように設定することが好ましい。酸素含有ガスの流量は、例えば０．１ｍＬ／ｍｉｎ（ｓｃｃｍ）以上５００ｍＬ／ｍｉｎ（ｓｃｃｍ）以下の範囲内から、上記流量比になるように設定することが好ましい。 <Process gas types and flow rates>
As a processing gas for the plasma oxidation treatment, it is preferable to use a rare gas for generating plasma and an oxygen-containing gas. As the rare gas, for example, Ar, Kr, Xe, He or the like can be used. As the oxygen-containing gas, for example, O 2 gas, ozone gas, or the like can be used. Among these, Ar gas is preferable as the rare gas, and O 2 gas is preferable as the oxygen-containing gas. The volume flow rate ratio of the oxygen-containing gas to the total processing gas in the processing vessel 2 (oxygen-containing gas flow rate / percentage of the total processing gas flow rate) makes it easy to form a thin film having a thickness of 1 nm or less by appropriately adjusting the oxidizing power. From the viewpoint of, for example, it is preferably in the range of 0.1% to 5%, and more preferably in the range of 0.5% to 3%. In the plasma oxidation treatment, it is preferable that the flow rate of the rare gas is set to the above flow rate ratio, for example, within a range of 100 mL / min (sccm) to 10000 mL / min (sccm). It is preferable to set the flow rate of the oxygen-containing gas so that the flow rate ratio is within the range of 0.1 mL / min (sccm) to 500 mL / min (sccm).
＜マイクロ波パワー＞
　プラズマ処理装置１を用いるプラズマ処理において、マイクロ波としては８６０ＭＨｚのマイクロ波を用いることが好ましい。また、着火時総パワーは、厚さ１ｎｍ以下の薄膜の形成を容易にする観点から、ウエハＷの面積当たり１Ｗ／ｃｍ２以下、好ましくは０．５Ｗ／ｃｍ２以上１Ｗ／ｃｍ２以下の範囲内、より好ましくは０．５Ｗ／ｃｍ２以上０．８Ｗ／ｃｍ２以下の範囲内、最も好ましくは０．５Ｗ／ｃｍ２以上０．６Ｗ／ｃｍ２以下の範囲内とする。例えば、３００ｍｍ径のウエハＷを被処理体とする場合、着火時総パワーを７００Ｗ以下、好ましくは３５０Ｗ以上７００Ｗ以下の範囲内とすることができる。着火時総パワーが１Ｗ／ｃｍ２もしくは７００Ｗを超えると、プラズマ着火直後の酸化レートが高くなり、厚さ１ｎｍ以下の薄膜の形成が困難になるか、あるいは、膜厚の制御性が著しく悪化する。着火時総パワーの下限は、安定したプラズマを生成させる観点から、ウエハＷの面積当たり０．５Ｗ／ｃｍ２以上とすることが好ましい。なお、プラズマ処理装置１では、７つのマイクロ波透過板７３からマイクロ波を導入するため、１つのマイクロ波透過板７３から導入されるマイクロ波の着火時パワーは、１００Ｗ以下とすることができる。 <Microwave power>
In the plasma processing using the plasma processing apparatus 1, it is preferable to use a microwave of 860 MHz as the microwave. Moreover, the ignition time of the total power, from the viewpoint of facilitating the formation of the following film thickness of 1 nm, per area of the wafer W 1W / cm 2 or less, preferably 0.5 W / cm 2 or more 1W / cm 2 or less in the range among them, more preferably 0.5 W / cm 2 or more 0.8 W / cm 2 within the range, and most preferably 0.5 W / cm 2 or more 0.6 W / cm 2 within the following ranges. For example, when a wafer W having a diameter of 300 mm is used as the object to be processed, the total power at the time of ignition can be 700 W or less, preferably 350 W or more and 700 W or less. If the total power during ignition exceeds 1 W / cm 2 or 700 W, the oxidation rate immediately after plasma ignition becomes high, and it becomes difficult to form a thin film having a thickness of 1 nm or less, or the controllability of the film thickness is remarkably deteriorated. . The lower limit of the total power during ignition is preferably set to 0.5 W / cm 2 or more per area of the wafer W from the viewpoint of generating stable plasma. In the plasma processing apparatus 1, since microwaves are introduced from the seven microwave transmission plates 73, the power at the time of ignition of the microwaves introduced from one microwave transmission plate 73 can be set to 100 W or less.
　また、プラズマ処理装置１を用いるプラズマ処理において、プロセス時総パワーは、着火時総パワーよりも小さくすることが可能であり、例えば着火時総パワーの１／３から１／２程度の範囲内とすることができる。例えば、プラズマ処理装置１で、３００ｍｍ径のウエハＷを処理する場合、着火時総パワーを４２０Ｗ以上７００Ｗ以下（ウエハＷの面積あたり０．６Ｗ／ｃｍ２以上１Ｗ／ｃｍ２以下）の範囲内とすると、プロセス時総パワーを１４０Ｗ以上３５０Ｗ以下（ウエハＷの面積あたり０．２Ｗ／ｃｍ２以上０．５Ｗ／ｃｍ２以下）の範囲内とすることができる。なお、プラズマ処理装置１では、７つのマイクロ波透過板７３からマイクロ波を導入するため、１つのマイクロ波透過板７３から導入されるマイクロ波のプロセス時パワーは、５０Ｗ以下とすることができる。また、条件によっては、着火時総パワーをそのままプロセス時総パワーとすることや、着火時総パワーよりも高いプロセス時総パワーを設定することも可能である。 Further, in the plasma processing using the plasma processing apparatus 1, the total power during the process can be made smaller than the total power during ignition, for example, within a range of about 1/3 to 1/2 of the total power during ignition. can do. For example, in the plasma processing apparatus 1, when processing a wafer W 300mm diameter, and the range of ignition when the total power 420W or 700W or less (per area of the wafer W 0.6 W / cm 2 or more 1W / cm 2 or less) Then, it can be in the range of 140W or more 350W less process time total power (per area of the wafer W 0.2 W / cm 2 or more 0.5 W / cm 2 or less). In the plasma processing apparatus 1, since microwaves are introduced from the seven microwave transmission plates 73, the process power of the microwaves introduced from the one microwave transmission plate 73 can be 50 W or less. Further, depending on the conditions, the total power at the time of ignition can be used as the total power at the time of the process, or the total power at the time of the process can be set higher than the total power at the time of ignition.
　これに対し、比較例のプラズマ処理装置５０１の場合は、上述のとおり、３００ｍｍ径のウエハＷを処理する場合、着火時パワー及びプロセス時パワーの最小値は１０００Ｗ（１．４２Ｗ／ｃｍ２）であり、この値以下では安定したプラズマの着火及び放電維持は困難である。従って、プラズマ処理装置５０１では、プラズマ処理装置１に比べると、プラズマ酸化処理における酸化レートが高くなり、厚さ１ｎｍ以下の薄膜の形成は困難である。 On the other hand, in the case of the plasma processing apparatus 501 of the comparative example, as described above, when processing a wafer W having a diameter of 300 mm, the minimum value of the ignition power and the process power is 1000 W (1.42 W / cm 2 ). If it is less than this value, stable plasma ignition and discharge maintenance are difficult. Therefore, compared with the plasma processing apparatus 1, the plasma processing apparatus 501 has a higher oxidation rate in the plasma oxidation process, and it is difficult to form a thin film having a thickness of 1 nm or less.
＜処理圧力＞
　処理圧力は、着火時総パワーを下げて厚さ１ｎｍ以下の薄膜の形成を容易にする観点から、例えば３０Ｐａ以上６００Ｐａ以下の範囲内が好ましく、８０Ｐａ以上３００Ｐａ以下の範囲内がより好ましい。ここで、図１０は、プラズマ処理装置１の１つのマイクロ波透過板７３を用いてＡｒガス１００％のプラズマを着火させる場合における圧力と着火時パワーの関係を表すパッシェン（Paschen）カーブである。ここでは、マイクロ波透過板７３の径が９０ｍｍである場合と、１５０ｍｍである場合とを比較している。このパッシェンカーブから、マイクロ波透過板７３が小径である９０ｍｍ径の方が１５０ｍｍ径に比べて着火時パワーが小さくてよいことが理解される。なお、比較例の単一マイクロ波方式のプラズマ処理装置５０１では、上記のとおり大型のマイクロ波透過板５７３を用いるため、さらに大きな着火時パワーが必要になる。 <Processing pressure>
From the viewpoint of facilitating the formation of a thin film having a thickness of 1 nm or less by reducing the total power during ignition, the treatment pressure is preferably in the range of 30 Pa to 600 Pa, and more preferably in the range of 80 Pa to 300 Pa. Here, FIG. 10 is a Paschen curve representing the relationship between the pressure and the ignition power when the plasma of Ar gas 100% is ignited using one microwave transmission plate 73 of the plasma processing apparatus 1. Here, the case where the diameter of the microwave transmission plate 73 is 90 mm is compared with the case where the diameter is 150 mm. From this Paschen curve, it is understood that the 90 mm diameter microwave transmission plate 73 may have a smaller ignition power than the 150 mm diameter. In the single microwave plasma processing apparatus 501 of the comparative example, since the large microwave transmission plate 573 is used as described above, a larger ignition power is required.
　また、同じ大きさのマイクロ波透過板７３を用いる場合でも、着火時パワーを小さくできる圧力範囲が存在することがわかる。図１０の例では、マイクロ波透過板７３が９０ｍｍ径である場合、例えば３０Ｐａ以上６００Ｐａ以下の範囲内で着火時パワーがほぼ１００Ｗを下回っている。また、マイクロ波透過板７３が１５０ｍｍ径である場合、例えば８０Ｐａ以上３００Ｐａ以下の範囲内で着火時パワーがほぼ１００Ｗを下回っている。 It can also be seen that there is a pressure range where the power during ignition can be reduced even when the microwave transmitting plate 73 having the same size is used. In the example of FIG. 10, when the microwave transmission plate 73 has a diameter of 90 mm, the ignition power is substantially less than 100 W within a range of 30 Pa to 600 Pa, for example. Further, when the microwave transmission plate 73 has a diameter of 150 mm, for example, the ignition power is less than about 100 W within a range of 80 Pa to 300 Pa.
＜処理温度＞
　ウエハＷの処理温度は、酸化レートを下げて厚さ１ｎｍ以下の薄膜の形成を容易にする観点から、例えば室温（３０℃）以上２００℃以下の範囲内とすることが好ましく、１００℃以下に設定することがより好ましい。なお、処理温度は載置台２１の温度を意味し、室温（３０℃）は加熱しないことを意味する。 <Processing temperature>
From the viewpoint of facilitating the formation of a thin film having a thickness of 1 nm or less by reducing the oxidation rate, the processing temperature of the wafer W is preferably, for example, in the range of room temperature (30 ° C.) to 200 ° C., and is preferably 100 ° C. or less. It is more preferable to set. In addition, processing temperature means the temperature of the mounting base 21, and room temperature (30 degreeC) means not heating.
　ここで、図１１は、異なる処理温度でウエハＷ表面のシリコンに対してプラズマ酸化処理をした場合のシリコン酸化膜の膜厚と処理時間との関係を示す特性図である。図１１の縦軸は、プラズマ処理によって形成されたシリコン酸化膜の膜厚を示し、横軸はプロセス時間を示している。なお、図１１の縦軸は、エリプソメーターによって測定した膜厚である。本明細書においては、特に注記しない限り、膜厚はエリプソメーターにより測定された値を意味する。 Here, FIG. 11 is a characteristic diagram showing the relationship between the film thickness of the silicon oxide film and the processing time when the plasma oxidation processing is performed on the silicon on the surface of the wafer W at different processing temperatures. The vertical axis in FIG. 11 indicates the film thickness of the silicon oxide film formed by plasma processing, and the horizontal axis indicates the process time. In addition, the vertical axis | shaft of FIG. 11 is the film thickness measured with the ellipsometer. In this specification, unless otherwise noted, the film thickness means a value measured by an ellipsometer.
　実験は、条件ａ～ｃで実施した。条件ａ，ｂは、７個のマイクロ波透過板７３を含むプラズマ処理装置１を使用し、条件ａでは処理温度を室温（３０℃）、条件ｂでは処理温度を５００℃とした。条件ｃは、比較のため、単一マイクロ波方式のプラズマ処理装置５０１を使用し、処理温度を３００℃とした。 The experiment was conducted under conditions a to c. Conditions a and b used the plasma processing apparatus 1 including seven microwave transmission plates 73. In condition a, the processing temperature was room temperature (30 ° C.), and in condition b, the processing temperature was 500 ° C. For the condition c, for comparison, a single microwave plasma processing apparatus 501 was used, and the processing temperature was 300 ° C.
　プラズマ処理装置１を用いるプラズマ酸化処理の温度以外の条件は以下の通りである。マイクロ波透過板７３とウエハＷとの間の間隔（ギャップ）を８５ｍｍに固定した。１つのマイクロ波透過板７３から導入されるマイクロ波のパワーを着火時パワー６０Ｗ、プロセス時パワー２０Ｗとした。処理容器２内の圧力は１３３Ｐａとした。プラズマ生成用の希ガスとして９９０ｓｃｃｍ（ｍＬ／ｍｉｎ）のＡｒを用い、酸素含有ガスとして１０ｓｃｃｍ（ｍＬ／ｍｉｎ）のＯ２を用いた。 Conditions other than the temperature of the plasma oxidation process using the plasma processing apparatus 1 are as follows. The interval (gap) between the microwave transmission plate 73 and the wafer W was fixed to 85 mm. The power of the microwave introduced from one microwave transmission plate 73 was set to 60 W during ignition and 20 W during process. The pressure in the processing container 2 was 133 Pa. 990 sccm (mL / min) Ar was used as a rare gas for plasma generation, and 10 sccm (mL / min) O 2 was used as an oxygen-containing gas.
　プラズマ処理装置５０１を用いるプラズマ酸化処理の条件ｃは以下の通りである。まず、処理温度（載置台５２１の設定温度）を３００℃とした。マイクロ波透過板５７３とウエハＷとの間の間隔（ギャップ）を８５ｍｍとし、マイクロ波の着火時パワーを１０００Ｗ、プロセス時パワーを１０００Ｗとした。処理容器５０２内の圧力は１３３Ｐａとした。プラズマ生成用の希ガスとして１９８０ｓｃｃｍ（ｍＬ／ｍｉｎ）のＡｒを用い、酸素含有ガスとして２０ｓｃｃｍ（ｍＬ／ｍｉｎ）のＯ２を用いた。 The conditions c of the plasma oxidation process using the plasma processing apparatus 501 are as follows. First, the processing temperature (set temperature of the mounting table 521) was set to 300 ° C. The interval (gap) between the microwave transmission plate 573 and the wafer W was 85 mm, the microwave ignition power was 1000 W, and the process power was 1000 W. The pressure in the processing container 502 was 133 Pa. 1980 sccm (mL / min) Ar was used as a rare gas for plasma generation, and 20 sccm (mL / min) O 2 was used as an oxygen-containing gas.
　図１１より、複数のマイクロ波でプラズマを生成させるプラズマ処理装置１を用いた条件ａでは、単一マイクロ波方式のプラズマ処理装置５０１を用いた条件ｃに比べ、同じプロセス時間でも形成されるシリコン酸化膜を大幅に薄膜化できている。なお、同じプラズマ処理装置１を用いた条件ｂでは、条件ａに比べると、酸化レートが大きく、厚さ１ｎｍ以下の薄膜形成における制御性が条件ａでの処理に比べ低下している。これは処理温度が５００℃の高温であるためと考えられる。しかし、図１１より、処理温度が１００℃以下であれば、膜厚の制御性よく厚さ１ｎｍ以下のシリコン酸化膜を形成することが十分に可能であると考えられる。 From FIG. 11, the condition a using the plasma processing apparatus 1 for generating plasma with a plurality of microwaves is formed even in the same process time as compared with the condition c using the single microwave plasma processing apparatus 501. The oxide film can be greatly thinned. Note that, in the condition b using the same plasma processing apparatus 1, the oxidation rate is higher than in the condition a, and the controllability in forming a thin film having a thickness of 1 nm or less is lower than the process in the condition a. This is presumably because the processing temperature is as high as 500 ° C. However, it can be seen from FIG. 11 that if the processing temperature is 100 ° C. or less, it is possible to form a silicon oxide film having a thickness of 1 nm or less with good controllability of film thickness.
＜酸化レート＞
　本実施の形態のプラズマ処理方法は、厚さ１ｎｍ以下の薄膜の形成を容易にする観点から、例えば、プラズマ着火のためのマイクロ波の供給を開始（パワーＯＮ）してから３０秒間における平均酸化レートを０．０３ｎｍ／秒以下とすることが好ましく、０．００５ｎｍ／秒以上０．０３ｎｍ／秒以下とすることがより好ましい。マイクロ波の供給開始から３０秒間における平均酸化レートを０．０３ｎｍ／秒以下にすることによって、短い処理時間でも膜厚の制御性が高まり、１ｎｍ以下、好ましくは０．５ｎｍ以上１ｎｍ以下の範囲内の任意の厚みで薄膜を形成できる。 <Oxidation rate>
From the viewpoint of facilitating the formation of a thin film having a thickness of 1 nm or less, the plasma processing method of the present embodiment is, for example, an average oxidation for 30 seconds after the microwave supply for plasma ignition is started (power ON). The rate is preferably 0.03 nm / second or less, and more preferably 0.005 nm / second or more and 0.03 nm / second or less. By controlling the average oxidation rate in 30 seconds from the start of microwave supply to 0.03 nm / second or less, the controllability of the film thickness is improved even in a short processing time, and it is 1 nm or less, preferably 0.5 nm or more and 1 nm or less. A thin film can be formed with an arbitrary thickness.
＜処理時間＞
　本実施の形態のプラズマ処理方法において、処理時間は、１ｎｍ以下の所望の厚みでシリコン酸化膜の形成が可能であれば特に制限はないが、上記酸化レートを考慮すると、プラズマ着火のためのマイクロ波パワーの供給を開始（パワーＯＮ）する時点を基準に、例えば１０秒以上１００秒以下の範囲内とすることが好ましい。 <Processing time>
In the plasma processing method of the present embodiment, the processing time is not particularly limited as long as the silicon oxide film can be formed with a desired thickness of 1 nm or less. However, considering the oxidation rate, the processing time is microscopic for plasma ignition. For example, it is preferably within a range of 10 seconds or more and 100 seconds or less with reference to the time point when the supply of wave power is started (power ON).
＜インピーダンス整合手順＞
　次に、本実施の形態のプラズマ処理方法におけるインピーダンス整合手順について、図１２Ａ，１２Ｂ及び図１３Ａ及び図１３Ｂを参照しながら説明する。本実施の形態のプラズマ処理方法では、複数のマイクロ波によりプラズマを着火するときにはインピーダンス整合を行わず、複数のマイクロ波により生成したプラズマによりウエハＷを処理するときにインピーダンス整合を行うことが好ましい。なお、プラズマ処理装置１において、インピーダンス整合は、チューナ６４の２つのスラグ７４Ａ，７４Ｂを上下に変位させることにより行われる（図４参照）。 <Impedance matching procedure>
Next, an impedance matching procedure in the plasma processing method of the present embodiment will be described with reference to FIGS. 12A and 12B and FIGS. 13A and 13B. In the plasma processing method of this embodiment, it is preferable that impedance matching is not performed when plasma is ignited by a plurality of microwaves, and impedance matching is performed when the wafer W is processed by plasma generated by a plurality of microwaves. In the plasma processing apparatus 1, impedance matching is performed by vertically moving the two slugs 74A and 74B of the tuner 64 (see FIG. 4).
　図１２Ａ及び図１２Ｂは、それぞれ、プラズマ処理装置１の一つのマイクロ波透過板７３からマイクロ波を導入し、酸素プラズマを着火させる際のインピーダンス整合の手順とプラズマ発光との関係を示している。図１２Ａ，図１２Ｂの縦軸は、発光分光分析（ＯＥＳ）による波長７７７ｎｍにおける酸素ラジカルの発光強度比を示し、横軸は、マイクロ波の設定パワーを示している。図１２Ａ及び図１２Ｂ中の四角のプロット（マッチングあり）は、圧力１３３Ｐａで処理ガスとしてＯ２ガスを１体積％含有するＡｒガスとＯ２ガスとの混合ガスを用い、インピーダンス整合を行ってプラズマを生成させた場合の設定パワーと発光強度との関係を示している。図１２Ａ及び図１２Ｂ中のひし形のプロット（マッチングなし）は、圧力１３３Ｐａで処理ガスとしてＯ２ガスを１体積％含有するＡｒガスとＯ２ガスとの混合ガスを用い、インピーダンス整合を行わずプラズマを生成させた場合の設定パワーと発光強度との関係を示している。 12A and 12B show the relationship between the impedance matching procedure and plasma emission when a microwave is introduced from one microwave transmission plate 73 of the plasma processing apparatus 1 to ignite oxygen plasma, respectively. The vertical axis of FIGS. 12A and 12B indicates the emission intensity ratio of oxygen radicals at a wavelength of 777 nm by emission spectroscopic analysis (OES), and the horizontal axis indicates the set power of the microwave. The square plots (with matching) in FIGS. 12A and 12B are plasmas obtained by impedance matching using a mixed gas of Ar gas and O 2 gas containing 1% by volume of O 2 gas as a processing gas at a pressure of 133 Pa. 3 shows the relationship between the set power and the light emission intensity in the case of generating. The rhombus plots (no matching) in FIGS. 12A and 12B show plasma without impedance matching using a mixed gas of Ar gas and O 2 gas containing 1% by volume of O 2 gas as a processing gas at a pressure of 133 Pa. 3 shows the relationship between the set power and the light emission intensity in the case of generating.
　また、図１３Ａ及び図１３Ｂは、それぞれ、プラズマ処理装置１の一つのマイクロ波透過板７３からマイクロ波を導入し、酸素プラズマを着火させる際のインピーダンス整合の手順を示すタイミングチャートである。図１３Ａ及び図１３Ｂにおいて、横軸は時間を示し、ｔ１は処理ガス導入開始、ｔ２はマイクロ波導入によるプラズマ着火、ｔ３はプロセス時パワーへの切り替え、ｔ４はプロセス終了（マイクロ波停止）、ｔ５は処理ガス供給停止、のタイミングを示している。なお、図１３Ａ及び図１３Ｂに示すタイミングチャートでは、処理ガスとしてＡｒガスとＯ２ガスを同時に処理容器２内に導入してプラズマを着火しているが、例えばＡｒガスを先に処理容器２内に導入してプラズマを着火し、後からＯ２ガスの導入を行うようにしてもよい。 13A and 13B are timing charts showing impedance matching procedures when a microwave is introduced from one microwave transmission plate 73 of the plasma processing apparatus 1 to ignite oxygen plasma. In FIGS. 13A and 13B, the horizontal axis indicates time, t1 is the start of process gas introduction, t2 is plasma ignition by microwave introduction, t3 is switching to process power, t4 is process end (microwave stop), t5 Indicates the timing of stopping the supply of the processing gas. In the timing charts shown in FIGS. 13A and 13B, Ar gas and O 2 gas are simultaneously introduced into the processing container 2 as processing gases to ignite the plasma. For example, Ar gas is first introduced into the processing container 2. May be introduced to ignite the plasma, and O 2 gas may be introduced later.
　図１２Ａ及び図１３Ａは、プラズマ着火と同時に、インピーダンス整合を開始させる方法（以下、方法Ａと記す）を示している。この場合の発光強度の変化を図１２Ａ中に太い矢印で示している。具体的には、方法Ａの場合は、着火時パワー１００Ｗでプラズマを着火させ（時点ｔ２）、同時に着火時パワーでインピーダンス整合を開始し、インピーダンス整合をしながら、プロセス時パワー５０Ｗに移行する（時点ｔ３）。 12A and 13A show a method of starting impedance matching simultaneously with plasma ignition (hereinafter referred to as method A). The change in emission intensity in this case is indicated by a thick arrow in FIG. 12A. Specifically, in the case of Method A, the plasma is ignited with an ignition power of 100 W (time t2), and simultaneously impedance matching is started with the ignition power, and the impedance is matched and the process power is shifted to 50 W ( Time t3).
　一方、図１２Ｂ及び図１３Ｂは、プラズマ着火と同時には、インピーダンス整合を開始せず、プロセスに移行するときに、インピーダンス整合を開始する方法（以下、方法Ｂと記す）を示している。この場合の発光強度の変化を図１２Ｂ中に太い矢印で示している。方法Ｂでは、着火時パワー１００Ｗでプラズマを着火させ（時点ｔ２）、着火後、インピーダンス整合を行うことなくプロセス時パワー５０Ｗに移行し（時点ｔ３）、プロセス時パワーでインピーダンス整合を開始する。 On the other hand, FIG. 12B and FIG. 13B show a method of starting impedance matching (hereinafter referred to as method B) when the process is shifted to the process without starting impedance matching simultaneously with plasma ignition. The change in emission intensity in this case is indicated by a thick arrow in FIG. 12B. In the method B, plasma is ignited with an ignition power of 100 W (time t2), and after ignition, the process shifts to a process power of 50 W without performing impedance matching (time t3), and impedance matching is started with the process power.
　図１２Ａと図１２Ｂから、インピーダンス整合を行うタイミングの違いによって、着火時パワー及びプロセス時パワーが同じでも、方法Ｂでは方法Ａに比べ、酸素ラジカルの発光を大幅に抑制できていることが理解される。すなわち、方法Ｂでは、着火時パワーでインピーダンス整合を行わないことによって、プラズマ着火時において、プラズマ中の酸化活性種である酸素ラジカルの生成量を方法Ａよりも大幅に抑制できている。 From FIG. 12A and FIG. 12B, it is understood that the emission of oxygen radicals can be greatly suppressed by Method B compared to Method A even if the ignition power and the process power are the same due to the difference in the timing of impedance matching. The That is, in Method B, impedance matching is not performed with ignition power, so that the amount of oxygen radicals, which are oxidation active species in plasma, can be greatly suppressed compared to Method A during plasma ignition.
　図１２Ａ及び図１２Ｂは、一つのマイクロ波によりプラズマを生成させた場合について示したものであるが、プラズマ処理装置１によって複数のマイクロ波でプラズマを生成させた場合も、同様に、方法Ｂでは方法Ａよりも、プラズマ着火時においてプラズマ中の酸化活性種である酸素ラジカルの生成量を大幅に抑制できる。従って、方法Ｂの手順を採用することによって、方法Ａの手順に比べ、プラズマ処理装置１を用いる薄膜（シリコン酸化膜）の形成において、プラズマ着火時の酸化を抑制することができ、膜厚の制御性が良好になり、一層の薄膜化が可能になる。このことを確認した実験結果について、図１４を参照しながら説明する。 FIGS. 12A and 12B show the case where plasma is generated by one microwave. However, when plasma is generated by a plurality of microwaves by the plasma processing apparatus 1, the method B similarly applies. Compared with method A, the amount of oxygen radicals, which are oxidation active species in plasma, can be significantly suppressed during plasma ignition. Therefore, by adopting the procedure of the method B, compared with the procedure of the method A, in the formation of the thin film (silicon oxide film) using the plasma processing apparatus 1, the oxidation at the time of plasma ignition can be suppressed. Controllability is improved and further thinning is possible. The experimental results confirming this will be described with reference to FIG.
　図１４は、プラズマ処理によって形成されたシリコン酸化膜の膜厚とプロセス時間との関係を示す特性図である。図１４の縦軸は、プラズマ処理によって形成されたシリコン酸化膜の膜厚を示し、横軸はプロセス時間を示している。実験は、下記の条件１～４で実施した。条件１～３は、７個のマイクロ波透過板７３を備えたプラズマ処理装置１を使用し、条件４は、比較のため、単一マイクロ波方式のプラズマ処理装置５０１を使用した。なお、シリコン酸化膜の膜厚の測定には、エリプソメーターを使用した。 FIG. 14 is a characteristic diagram showing the relationship between the film thickness of the silicon oxide film formed by plasma processing and the process time. The vertical axis in FIG. 14 indicates the film thickness of the silicon oxide film formed by plasma treatment, and the horizontal axis indicates the process time. The experiment was performed under the following conditions 1 to 4. Conditions 1 to 3 used the plasma processing apparatus 1 including seven microwave transmission plates 73, and Condition 4 used a single microwave plasma processing apparatus 501 for comparison. An ellipsometer was used to measure the thickness of the silicon oxide film.
＜条件１＞
　プラズマ生成方式：複数マイクロ波
　着火時総パワー：４２０Ｗ
　プロセス時総パワー：１４０Ｗ
　着火時パワー：６０Ｗ
　プロセス時パワー：２０Ｗ
　インピーダンス整合：方法Ｂ
＜条件２＞
　プラズマ生成方式：複数マイクロ波
　着火時総パワー：７００Ｗ
　プロセス時総パワー：３５０Ｗ
　着火時パワー：１００Ｗ
　プロセス時パワー：５０Ｗ
　インピーダンス整合：方法Ｂ
＜条件３＞
　プラズマ生成方式：複数マイクロ波
　着火時総パワー：７００Ｗ
　プロセス時総パワー：３５０Ｗ
　着火時パワー：１００Ｗ
　プロセス時パワー：５０Ｗ
　インピーダンス整合：方法Ａ
＜条件４＞
　プラズマ生成方式：単一マイクロ波
　着火時パワー：１０００Ｗ
　プロセス時パワー：１０００Ｗ
　インピーダンス整合：方法Ａ <Condition 1>
Plasma generation method: Multiple microwaves Total power at ignition: 420W
Total power during process: 140W
Power at ignition: 60W
Process power: 20W
Impedance matching: Method B
<Condition 2>
Plasma generation method: Multiple microwaves Total power at ignition: 700W
Total power during process: 350W
Ignition power: 100W
Process power: 50W
Impedance matching: Method B
<Condition 3>
Plasma generation method: Multiple microwaves Total power at ignition: 700W
Total power during process: 350W
Ignition power: 100W
Process power: 50W
Impedance matching: Method A
<Condition 4>
Plasma generation method: Single microwave Ignition power: 1000W
Process power: 1000W
Impedance matching: Method A
　プラズマ処理装置１を用いるプラズマ酸化処理の他の条件は以下の通りである。マイクロ波透過板７３とウエハＷとの間の間隔（ギャップ）を８５ｍｍに固定した。処理容器２内の圧力は１３３Ｐａとした。プラズマ生成用の希ガスとして９９０ｓｃｃｍ（ｍＬ／ｍｉｎ）のＡｒを用い、酸素含有ガスとして１０ｓｃｃｍ（ｍＬ／ｍｉｎ）のＯ２を用いた。また、処理温度を３０℃とした。 Other conditions for the plasma oxidation process using the plasma processing apparatus 1 are as follows. The interval (gap) between the microwave transmission plate 73 and the wafer W was fixed to 85 mm. The pressure in the processing container 2 was 133 Pa. 990 sccm (mL / min) Ar was used as a rare gas for plasma generation, and 10 sccm (mL / min) O 2 was used as an oxygen-containing gas. The processing temperature was 30 ° C.
　プラズマ処理装置５０１を用いるプラズマ酸化処理の他の条件は以下の通りである。マイクロ波透過板５７３とウエハＷとの間の間隔（ギャップ）を８５ｍｍとした。プラズマ生成用の希ガスとして１９８０ｓｃｃｍ（ｍＬ／ｍｉｎ）のＡｒを用い、酸素含有ガスとして２０ｓｃｃｍ（ｍＬ／ｍｉｎ）のＯ２を用いた。また、処理温度を３００℃とした。 Other conditions for the plasma oxidation process using the plasma processing apparatus 501 are as follows. The interval (gap) between the microwave transmission plate 573 and the wafer W was set to 85 mm. 1980 sccm (mL / min) Ar was used as a rare gas for plasma generation, and 20 sccm (mL / min) O 2 was used as an oxygen-containing gas. The processing temperature was 300 ° C.
　図１４より、複数のマイクロ波でプラズマを生成させるプラズマ処理装置１を用いた条件１～３では、単一マイクロ波方式のプラズマ処理装置５０１を用いた条件４に比べ、着火時総パワー及びプロセス時総パワーの両方が小さいため、同じプロセス時間でも形成されるシリコン酸化膜を大幅に薄膜化できている。特に、インピーダンス整合を方法Ｂで行った条件１及び条件２では、プロセス開始（プロセス時間０）から２０秒経過後でもシリコン酸化膜の膜厚は１ｎｍ以下であり、インピーダンス整合を方法Ａで行った条件３に比べても良好な結果が得られた。一方、条件４では、酸化レートが大きすぎるため、シリコン酸化膜の膜厚を１ｎｍ以下に制御することは現実的に不可能である。 From FIG. 14, the conditions 1 to 3 using the plasma processing apparatus 1 for generating plasma with a plurality of microwaves are compared to the condition 4 using the single microwave plasma processing apparatus 501 and the total power and process during ignition. Since both the time total power is small, the silicon oxide film formed even in the same process time can be greatly thinned. In particular, in conditions 1 and 2 where impedance matching was performed by method B, the film thickness of the silicon oxide film was 1 nm or less even after 20 seconds had elapsed from the start of the process (process time 0), and impedance matching was performed by method A. Even when compared with condition 3, good results were obtained. On the other hand, under condition 4, since the oxidation rate is too large, it is practically impossible to control the thickness of the silicon oxide film to 1 nm or less.
　図１４において、プロセス時間０は、方法Ａ、方法Ｂともに、マイクロ波パワーをオン（ＯＮ）してプラズマを着火してから、５秒間かけて安定化させた後、プロセス時パワーに切り替え（図１３Ａ，１３Ｂの時点ｔ３）、さらにプロセス時パワーで５秒間かけて安定化させた時点を意味する。従って、図１４において、プロセス時間０は、方法Ａ，方法Ｂともに、マイクロ波パワーのオン（ＯＮ）から約１０秒程度経過している。このため、図１４の条件１～３では、プロセス時間０であっても、すでに０．９ｎｍ程度のシリコン酸化膜の膜厚が計測されている。このように、プロセス時間０までに形成される膜厚を考慮すると、条件１～３では、プロセス時間０から２０秒経過後までの平均酸化レートは、明らかに０．００５ｎｍ／秒程度である。条件１～３では、このような低酸化レートのプラズマ処理が可能であり、特に、インピーダンス整合を方法Ｂで行った条件１及び条件２では、プロセス時間０に至るまでの着火直後のプラズマによる酸化を効果的に抑制できるため、シリコン酸化膜の膜厚を１ｎｍ以下の任意の膜厚で制御性良く形成できる。 In FIG. 14, the process time 0 is switched to the process power after the microwave power is turned on (ON) and the plasma is ignited and stabilized for 5 seconds in both the method A and the method B (FIG. 14). 13A and 13B at time t3), and the time at which the process power is stabilized for 5 seconds. Therefore, in FIG. 14, the process time 0 is about 10 seconds after the microwave power is turned on (ON) in both the method A and the method B. Therefore, under conditions 1 to 3 in FIG. 14, even if the process time is 0, the thickness of the silicon oxide film of about 0.9 nm has already been measured. Thus, when the film thickness formed before the process time 0 is taken into consideration, under the conditions 1 to 3, the average oxidation rate from the process time 0 to 20 seconds later is clearly about 0.005 nm / second. Under conditions 1 to 3, plasma processing at such a low oxidation rate is possible. In particular, under conditions 1 and 2 where impedance matching is performed by method B, oxidation by plasma immediately after ignition until process time 0 is reached. Therefore, the silicon oxide film can be formed with an arbitrary film thickness of 1 nm or less with good controllability.
　以上、本実施の形態のプラズマ処理方法によれば、被処理体であるウエハＷの表面に、１ｎｍ以下の膜厚のシリコン酸化膜を、膜厚の制御性よく形成することができる。 As described above, according to the plasma processing method of the present embodiment, a silicon oxide film having a thickness of 1 nm or less can be formed on the surface of the wafer W, which is an object to be processed, with good controllability of the thickness.
［第２の実施の形態のプラズマ処理方法］
　次に、プラズマ処理装置１を用いて行われる本発明の第２の実施の形態に係るプラズマ処理方法について説明する。本実施の形態のプラズマ処理方法は、プラズマ処理装置１の処理容器２内に複数のマイクロ波によりプラズマを生成させて被処理体であるウエハＷを処理し、例えばウエハＷの表面のシリコンを窒化してシリコン窒化膜を形成する。 [Plasma Processing Method of Second Embodiment]
Next, a plasma processing method according to the second embodiment of the present invention performed using the plasma processing apparatus 1 will be described. In the plasma processing method of the present embodiment, plasma is generated in a processing container 2 of a plasma processing apparatus 1 by a plurality of microwaves to process a wafer W as an object to be processed, for example, nitriding silicon on the surface of the wafer W Then, a silicon nitride film is formed.
　本実施の形態では、処理容器２内に複数のマイクロ波によりプラズマを生成させる方式のプラズマ処理装置１を用い、厚さ１ｎｍ（１０オングストローム）以下、好ましくは０．５ｎｍ以上１ｎｍ以下の範囲内の極薄膜を形成するために、低いマイクロ波パワーでプラズマ窒化処理を行う。具体的には、本実施の形態のプラズマ処理方法では、着火時総パワーを、ウエハＷの面積当たり１Ｗ／ｃｍ２以下、好ましくは０．８Ｗ／ｃｍ２以下、より好ましくは０．６Ｗ／ｃｍ２以下とする。例えば、３００ｍｍ径のウエハＷを被処理体とする場合、着火時総パワーを７００Ｗ以下、好ましくは５６０Ｗ以下、より好ましくは４２０Ｗ以下とする。 In the present embodiment, a plasma processing apparatus 1 that generates plasma by a plurality of microwaves in the processing container 2 is used, and the thickness is 1 nm (10 angstroms) or less, preferably 0.5 nm or more and 1 nm or less. In order to form an ultrathin film, plasma nitriding is performed with low microwave power. Specifically, in the plasma processing method of the present embodiment, the total power during ignition, per area of the wafer W 1W / cm 2 or less, preferably 0.8 W / cm 2 or less, more preferably 0.6 W / cm 2 or less. For example, when a wafer W having a diameter of 300 mm is used as an object to be processed, the total power upon ignition is set to 700 W or less, preferably 560 W or less, more preferably 420 W or less.
　本実施の形態のプラズマ処理方法で、着火時総パワーを上記のように規定する理由は、第１の実施の形態と同様である。 The reason why the total power at the time of ignition is specified as described above in the plasma processing method of the present embodiment is the same as that of the first embodiment.
＜プラズマ窒化処理の条件＞
　次に、プラズマ処理装置１を用いて、１ｎｍ以下の膜厚のシリコン窒化膜を形成するための主要な条件として、処理ガスの種類と流量、処理圧力、マイクロ波パワー、処理温度、窒化レート、処理時間、インピーダンス整合手順を挙げて詳細に説明する。なお、これらの条件は、制御部８の記憶部８３にレシピとして保存されている。そして、プロセスコントローラ８１がそのレシピを読み出してプラズマ処理装置１の各構成部へ制御信号を送出することにより、所望の条件でプラズマ窒化処理が行われる。 <Conditions for plasma nitriding>
Next, the main conditions for forming a silicon nitride film having a thickness of 1 nm or less using the plasma processing apparatus 1 are as follows: type and flow rate of processing gas, processing pressure, microwave power, processing temperature, nitriding rate, The processing time and impedance matching procedure will be described in detail. Note that these conditions are stored as recipes in the storage unit 83 of the control unit 8. Then, the process controller 81 reads the recipe and sends a control signal to each component of the plasma processing apparatus 1, so that the plasma nitriding process is performed under a desired condition.
＜処理ガスの種類と流量＞
　プラズマ窒化処理の処理ガスとしては、プラズマ生成用の希ガスと窒素含有ガスを用いることが好ましい。希ガスとしては、例えば、Ａｒ、Ｋｒ、Ｘｅ、Ｈｅ等を使用することができる。窒素含有ガスとしては、例えば、窒素ガス、ＮＨ３ガス等が使用される。これらの中でも、希ガスとしてはＡｒガスが、窒素含有ガスとしてはＮ２ガスが、それぞれ好ましい。処理容器２内における全処理ガスに対する窒素含有ガスの体積流量比率（窒素含有ガス流量／全処理ガス流量の百分率）は、窒化力を適度に調節して厚さ１ｎｍ以下の薄膜の形成を容易にする観点から、例えば、５％以上２５％以下の範囲内とすることが好ましく、１０％以上２０％以下の範囲内とすることがより好ましい。プラズマ窒化処理では、例えば希ガスの流量は、１００ｍＬ／ｍｉｎ（ｓｃｃｍ）以上１００００ｍＬ／ｍｉｎ（ｓｃｃｍ）以下の範囲内から、上記流量比になるように設定することが好ましい。窒素含有ガスの流量は５ｍＬ／ｍｉｎ（ｓｃｃｍ）以上２５００ｍＬ／ｍｉｎ（ｓｃｃｍ）以下の範囲内から、上記流量比になるように設定することが好ましい。 <Process gas types and flow rates>
As a processing gas for plasma nitriding, it is preferable to use a rare gas for generating plasma and a nitrogen-containing gas. As the rare gas, for example, Ar, Kr, Xe, He or the like can be used. As the nitrogen-containing gas, for example, nitrogen gas, NH 3 gas or the like is used. Among these, Ar gas is preferable as the rare gas, and N 2 gas is preferable as the nitrogen-containing gas. The volume flow ratio of the nitrogen-containing gas to the total processing gas in the processing container 2 (nitrogen-containing gas flow rate / percentage of the total processing gas flow rate) is easy to form a thin film having a thickness of 1 nm or less by appropriately adjusting the nitriding power. Therefore, for example, it is preferably in the range of 5% to 25%, and more preferably in the range of 10% to 20%. In the plasma nitriding treatment, for example, the flow rate of the rare gas is preferably set to be within the range of 100 mL / min (sccm) or more and 10000 mL / min (sccm) or less so that the above flow rate ratio is obtained. The flow rate of the nitrogen-containing gas is preferably set to be within the range of 5 mL / min (sccm) or more and 2500 mL / min (sccm) or less so that the above flow rate ratio is obtained.
＜マイクロ波パワー＞
　プラズマ処理装置１を用いるプラズマ処理において、着火時総パワーは、厚さ１ｎｍ以下の薄膜の形成を容易にする観点から、ウエハＷの面積当たり１Ｗ／ｃｍ２以下、好ましくは０．５Ｗ／ｃｍ２以上１Ｗ／ｃｍ２以下の範囲内、より好ましくは０．５Ｗ／ｃｍ２以上０．８Ｗ／ｃｍ２以下の範囲内、最も好ましくは０．５Ｗ／ｃｍ２以上０．６Ｗ／ｃｍ２以下の範囲内とする。例えば、３００ｍｍ径のウエハＷを被処理体とする場合、着火時総パワーを７００Ｗ以下、好ましくは３５０Ｗ以上７００Ｗ以下の範囲内とすることができる。着火時総パワーが１Ｗ／ｃｍ２もしくは７００Ｗを超えると、プラズマ着火直後の窒化レートが高くなり、厚さ１ｎｍ以下の薄膜の形成が困難になるか、あるいは、膜厚の制御性が著しく悪化する。着火時総パワーの下限は、安定したプラズマを生成させる観点から、ウエハＷの面積当たり０．５Ｗ／ｃｍ２以上とすることが好ましい。なお、プラズマ処理装置１では、７つのマイクロ波透過板７３からマイクロ波を導入するため、１つのマイクロ波透過板７３から導入されるマイクロ波の着火時パワーは、１００Ｗ以下とすることができる。 <Microwave power>
In plasma processing using the plasma processing apparatus 1, the total power during ignition is 1 W / cm 2 or less, preferably 0.5 W / cm 2 per area of the wafer W from the viewpoint of facilitating formation of a thin film having a thickness of 1 nm or less. above 1W / cm 2 within the range, more preferably 0.5 W / cm 2 or more 0.8 W / cm 2 within the range, most preferably 0.5 W / cm 2 or more 0.6 W / cm 2 or less in the range Within. For example, when a wafer W having a diameter of 300 mm is used as the object to be processed, the total power at the time of ignition can be 700 W or less, preferably 350 W or more and 700 W or less. When the total power during ignition exceeds 1 W / cm 2 or 700 W, the nitriding rate immediately after plasma ignition becomes high, and it becomes difficult to form a thin film having a thickness of 1 nm or less, or the controllability of the film thickness is remarkably deteriorated. . The lower limit of the total power during ignition is preferably set to 0.5 W / cm 2 or more per area of the wafer W from the viewpoint of generating stable plasma. In the plasma processing apparatus 1, since microwaves are introduced from the seven microwave transmission plates 73, the power at the time of ignition of the microwaves introduced from one microwave transmission plate 73 can be set to 100 W or less.
　また、プラズマ処理装置１を用いるプラズマ処理において、プロセス時総パワーは、着火時総パワーよりも小さくすることが可能であり、例えば着火時総パワーの１／３から１／２程度の範囲内とすることができる。例えば、プラズマ処理装置１で、３００ｍｍ径のウエハＷを処理する場合、着火時総パワーを４２０Ｗ以上７００Ｗ以下（ウエハＷの面積あたり０．６Ｗ／ｃｍ２以上１Ｗ／ｃｍ２以下）の範囲内とすると、プロセス時総パワーを１４０Ｗ以上３５０Ｗ以下（ウエハＷの面積あたり０．２Ｗ／ｃｍ２以上０．５Ｗ／ｃｍ２以下）の範囲内とすることができる。なお、プラズマ処理装置１では、７つのマイクロ波透過板７３からマイクロ波を導入するため、１つのマイクロ波透過板７３から導入されるマイクロ波のプロセス時パワーは、５０Ｗ以下とすることができる。また、条件によっては、着火時総パワーをそのままプロセス時総パワーとすることや、着火時総パワーよりも高いプロセス時総パワーを設定することも可能である。 Further, in the plasma processing using the plasma processing apparatus 1, the total power during the process can be made smaller than the total power during ignition, for example, within a range of about 1/3 to 1/2 of the total power during ignition. can do. For example, in the plasma processing apparatus 1, when processing a wafer W 300mm diameter, and the range of ignition when the total power 420W or 700W or less (per area of the wafer W 0.6 W / cm 2 or more 1W / cm 2 or less) Then, it can be in the range of 140W or more 350W less process time total power (per area of the wafer W 0.2 W / cm 2 or more 0.5 W / cm 2 or less). In the plasma processing apparatus 1, since microwaves are introduced from the seven microwave transmission plates 73, the process power of the microwaves introduced from the one microwave transmission plate 73 can be 50 W or less. Further, depending on the conditions, the total power at the time of ignition can be used as the total power at the time of the process, or the total power at the time of the process can be set higher than the total power at the time of ignition.
　これに対し、第１の実施の形態で説明した比較例のプラズマ処理装置５０１の場合は、上述のとおり、３００ｍｍ径のウエハＷを処理する場合、着火時パワー及びプロセス時パワーの最小値は１０００Ｗ（１．４２Ｗ／ｃｍ２）であり、この値以下では安定したプラズマの着火及び放電維持は困難である。従って、プラズマ処理装置５０１では、プラズマ処理装置１に比べると、プラズマ窒化処理における窒化レートが高くなり、厚さ１ｎｍ以下の薄膜の形成は困難である。 On the other hand, in the case of the plasma processing apparatus 501 of the comparative example described in the first embodiment, as described above, when processing a wafer W having a diameter of 300 mm, the minimum value of the ignition power and the process power is 1000 W. It is (1.42 W / cm 2 ), and it is difficult to stably ignite plasma and maintain discharge below this value. Therefore, in the plasma processing apparatus 501, compared with the plasma processing apparatus 1, the nitriding rate in the plasma nitriding process is high, and it is difficult to form a thin film having a thickness of 1 nm or less.
＜処理圧力＞
　処理圧力は、着火時総パワーを下げて厚さ１ｎｍ以下の薄膜の形成を容易にする観点から、例えば１０Ｐａ以上６００Ｐａ以下の範囲内が好ましく、２０Ｐａ以上３００Ｐａ以下の範囲内がより好ましい。 <Processing pressure>
From the viewpoint of facilitating the formation of a thin film having a thickness of 1 nm or less by reducing the total power during ignition, the treatment pressure is preferably in the range of 10 Pa to 600 Pa, and more preferably in the range of 20 Pa to 300 Pa.
＜処理温度＞
　ウエハＷの処理温度は、窒化レートを下げて厚さ１ｎｍ以下の薄膜の形成を容易にする観点から、例えば室温（３０℃）以上２００℃以下の範囲内とすることが好ましく、１００℃以下に設定することがより好ましい。なお、処理温度は載置台２１の温度を意味し、室温（３０℃）は加熱しないことを意味する。 <Processing temperature>
From the viewpoint of facilitating the formation of a thin film having a thickness of 1 nm or less by lowering the nitriding rate, the processing temperature of the wafer W is preferably, for example, in the range of room temperature (30 ° C.) to 200 ° C., and is preferably 100 ° C. or less. It is more preferable to set. In addition, processing temperature means the temperature of the mounting base 21, and room temperature (30 degreeC) means not heating.
＜窒化レート＞
　本実施の形態のプラズマ処理方法は、厚さ１ｎｍ以下の薄膜の形成を容易にする観点から、例えばプラズマ着火のためのマイクロ波の供給を開始（パワーＯＮ）してから３０秒間における平均窒化レートが０．０５ｎｍ／秒以下であることが好ましく、０．００５ｎｍ／秒以上０．０５ｎｍ／秒以下であることがより好ましい。マイクロ波の供給開始から３０秒間における平均窒化レートを０．０５ｎｍ／秒以下にすることによって、短い処理時間でも膜厚の制御性が高まり、１ｎｍ以下、好ましくは０．５ｎｍ以上１ｎｍ以下の任意の厚みで薄膜を形成できる。 <Nitriding rate>
From the viewpoint of facilitating the formation of a thin film having a thickness of 1 nm or less, the plasma processing method of the present embodiment has an average nitriding rate for 30 seconds after the supply of microwaves for plasma ignition is started (power ON), for example. Is preferably 0.05 nm / second or less, and more preferably 0.005 nm / second or more and 0.05 nm / second or less. By controlling the average nitriding rate in 30 seconds from the start of microwave supply to 0.05 nm / second or less, the controllability of the film thickness is enhanced even in a short processing time, and the film thickness is 1 nm or less, preferably 0.5 nm to 1 nm. A thin film can be formed with a thickness.
＜処理時間＞
　本実施の形態のプラズマ処理方法において、処理時間は、１ｎｍ以下の所望の厚みでシリコン窒化膜の形成が可能であれば特に制限はないが、上記窒化レートを考慮すると、プラズマ着火のためのマイクロ波パワーの供給を開始（パワーＯＮ）する時点を基準に、例えば１０秒以上１００秒以下の範囲内とすることが好ましい。 <Processing time>
In the plasma processing method of the present embodiment, the processing time is not particularly limited as long as the silicon nitride film can be formed with a desired thickness of 1 nm or less. For example, it is preferably within a range of 10 seconds or more and 100 seconds or less with reference to the time point when the supply of wave power is started (power ON).
＜インピーダンス整合手順＞
　本実施の形態のプラズマ処理方法におけるインピーダンス整合手順は、第１の実施の形態におけるインピーダンス整合手順と同様である。本実施の形態においても、方法Ｂを採用することによって、方法Ａに比べ、プラズマ処理装置１を用いる薄膜（シリコン窒化膜）の形成において、プラズマ着火時の窒化を抑制することができ、膜厚の制御性が良好になり、一層の薄膜化が可能になる。 <Impedance matching procedure>
The impedance matching procedure in the plasma processing method of the present embodiment is the same as the impedance matching procedure in the first embodiment. Also in this embodiment, by adopting the method B, nitriding at the time of plasma ignition can be suppressed in the formation of a thin film (silicon nitride film) using the plasma processing apparatus 1 as compared with the method A. The controllability of the film becomes better, and it becomes possible to further reduce the film thickness.
　次に、本実施の形態のプラズマ処理方法の効果を示す実験結果について、図１５を参照して説明する。図１５は、プラズマ処理によって形成されたシリコン窒化膜の膜厚とプロセス時間との関係を示す特性図である。図１５の縦軸は、プラズマ処理によって形成されたシリコン窒化膜の膜厚を示し、横軸はプロセス時間を示している。実験は、７個のマイクロ波透過板７３を備えたプラズマ処理装置１を使用して以下の条件で実施した。マイクロ波透過板７３とウエハＷとの間の間隔（ギャップ）は８５ｍｍに固定した。着火時総パワーは７００Ｗ、プロセス時総パワーは３５０Ｗ、着火時パワーは１００Ｗ、プロセス時パワーは５０Ｗに設定した。処理容器２内の圧力は２０Ｐａとした。プラズマ生成用の希ガスとして１０００ｓｃｃｍ（ｍＬ／ｍｉｎ）のＡｒを用い、窒素含有ガスとして２０ｓｃｃｍ（ｍＬ／ｍｉｎ）のＮ２を用いた。また、処理温度を３０℃とした。インピーダンス整合は、プラズマ着火と同時には、インピーダンス整合を開始せず、プロセスに移行するときに、インピーダンス整合を開始する方法Ｂ（第１の実施の形態を参照）により実施した。シリコン窒化膜の膜厚の測定には、エリプソメーターを使用した。 Next, experimental results showing the effects of the plasma processing method of the present embodiment will be described with reference to FIG. FIG. 15 is a characteristic diagram showing the relationship between the film thickness of the silicon nitride film formed by plasma processing and the process time. The vertical axis in FIG. 15 indicates the film thickness of the silicon nitride film formed by plasma processing, and the horizontal axis indicates the process time. The experiment was performed using the plasma processing apparatus 1 including seven microwave transmission plates 73 under the following conditions. The interval (gap) between the microwave transmission plate 73 and the wafer W was fixed to 85 mm. The total power during ignition was set to 700 W, the total power during process was set to 350 W, the power during ignition was set to 100 W, and the power during process was set to 50 W. The pressure in the processing container 2 was 20 Pa. 1000 sccm (mL / min) Ar was used as a rare gas for plasma generation, and 20 sccm (mL / min) N 2 was used as a nitrogen-containing gas. The processing temperature was 30 ° C. Impedance matching was performed by method B (see the first embodiment) in which impedance matching is not started at the same time as plasma ignition, but impedance matching is started when the process proceeds. An ellipsometer was used to measure the thickness of the silicon nitride film.
　図１５より、複数のマイクロ波でプラズマを生成させるプラズマ処理装置１を用い、着火時総パワー及びプロセス時総パワーの両方を小さく抑えてプラズマ処理を行うことにより、プロセス開始（プロセス時間０）から１０秒経過後でもシリコン窒化膜の膜厚を１ｎｍ以下にコントロールできることが確認できた。 From FIG. 15, by using the plasma processing apparatus 1 that generates plasma with a plurality of microwaves and performing plasma processing while suppressing both the total power during ignition and the total power during process, the process starts (process time 0). It was confirmed that the film thickness of the silicon nitride film could be controlled to 1 nm or less even after 10 seconds.
　また、図１５において、プロセス時間０は、マイクロ波パワーをオン（ＯＮ）してプラズマを着火してから、５秒間かけて安定化させた後、プロセス時パワーに切り替え、さらにプロセス時パワーで５秒間かけて安定化させた時点を意味する。従って、図１５において、プロセス時間０は、マイクロ波パワーのオン（ＯＮ）から約１０秒程度経過している。このため、図１５では、プロセス時間０であっても、すでに０．５ｎｍ程度のシリコン窒化膜の膜厚が計測されている。このように、プロセス時間０までに形成される膜厚を考慮すると、プロセス時間０から１０秒経過後までの平均窒化レートは、明らかに０．０５ｎｍ／ｓｅｃ程度である。また、インピーダンス整合を方法Ｂで行うことによって、プロセス時間０に至るまでの着火直後のプラズマによる窒化を効果的に抑制できている。 Further, in FIG. 15, the process time 0 is the time when the microwave power is turned on (ON) and the plasma is ignited, and is stabilized for 5 seconds, and then switched to the process power. It means the time of stabilization over a second. Therefore, in FIG. 15, the process time 0 has passed about 10 seconds after the microwave power is turned on. Therefore, in FIG. 15, even when the process time is 0, the thickness of the silicon nitride film of about 0.5 nm has already been measured. Thus, considering the film thickness formed before the process time 0, the average nitridation rate from the process time 0 to 10 seconds later is clearly about 0.05 nm / sec. Further, by performing impedance matching by the method B, nitridation by plasma immediately after ignition until reaching the process time 0 can be effectively suppressed.
　以上、本実施の形態のプラズマ処理方法によれば、被処理体であるウエハＷの表面に、１ｎｍ以下の膜厚のシリコン窒化膜を、膜厚の制御性よく形成することができる。 As described above, according to the plasma processing method of the present embodiment, a silicon nitride film having a thickness of 1 nm or less can be formed on the surface of the wafer W that is an object to be processed with good controllability of the film thickness.
　なお、本発明は、上記各実施の形態に限定されず、種々の変更が可能である。例えば、本発明のプラズマ処理方法は、半導体ウエハを被処理体とする場合に限らず、例えば太陽電池パネルの基板やフラットパネルディスプレイ用基板を被処理体とする場合にも適用できる。 The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the plasma processing method of the present invention is not limited to a case where a semiconductor wafer is used as an object to be processed, but can also be applied to a case where, for example, a solar cell panel substrate or a flat panel display substrate is used as an object to be processed.
　また、上記実施の形態では、ウエハＷの表面のシリコンをプラズマ酸化処理又はプラズマ窒化処理する場合を例に挙げたが、処理対象はシリコンに限るものではない。例えば、プラズマ酸化処理の対象は、シリコン窒化膜（ＳｉＮ膜）でもよいし、プラズマ窒化処理の対象は、シリコン酸化膜（ＳｉＯ２膜）でもよく、さらに別の種類の膜でもよい。 In the above embodiment, the case where the silicon on the surface of the wafer W is subjected to the plasma oxidation process or the plasma nitridation process has been described as an example. However, the processing target is not limited to silicon. For example, the target of the plasma oxidation process may be a silicon nitride film (SiN film), and the target of the plasma nitridation process may be a silicon oxide film (SiO 2 film) or another type of film.
　本国際出願は、２０１２年２月６日に出願された日本国特許出願２０１２－０２３０３８号に基づく優先権を主張するものであり、この出願の全内容をここに援用する。
 
 
  This international application claims priority based on Japanese Patent Application No. 2012-023038 filed on February 6, 2012, the entire contents of which are incorporated herein by reference.


Claims (17)

  1. 　複数のマイクロ波により処理容器内にプラズマを生成させて被処理体を処理するプラズマ処理装置を用い、前記被処理体の表面に薄膜を形成するプラズマ処理方法であって、
    　前記複数のマイクロ波によりプラズマを着火するときのマイクロ波のパワーの合計が前記被処理体の面積当たり１Ｗ／ｃｍ２以下であり、かつ、前記薄膜の膜厚が１ｎｍ以下であることを特徴とするプラズマ処理方法。     A plasma processing method for forming a thin film on a surface of a target object using a plasma processing apparatus that generates a plasma in a processing container by a plurality of microwaves to process the target object,
    The total microwave power when the plasma is ignited by the plurality of microwaves is 1 W / cm 2 or less per area of the object to be processed, and the thickness of the thin film is 1 nm or less. A plasma processing method.
  2. 　複数のマイクロ波により処理容器内にプラズマを生成させて被処理体を処理するプラズマ処理装置を用い、前記被処理体の表面に薄膜を形成するプラズマ処理方法であって、
    　前記被処理体の径が３００ｍｍ以上であり、
    　前記複数のマイクロ波によりプラズマを着火するときのマイクロ波のパワーの合計が７００Ｗ以下であり、かつ、前記薄膜の膜厚が１ｎｍ以下であることを特徴とするプラズマ処理方法。     A plasma processing method for forming a thin film on a surface of a target object using a plasma processing apparatus that generates a plasma in a processing container by a plurality of microwaves to process the target object,
    The diameter of the object to be processed is 300 mm or more,
    A plasma processing method, wherein the total power of microwaves when the plasma is ignited by the plurality of microwaves is 700 W or less, and the thickness of the thin film is 1 nm or less.
  3. 　前記プラズマにより被処理体を処理する処理温度が、１００℃以下である請求項１に記載のプラズマ処理方法。 The plasma processing method according to claim 1, wherein a processing temperature for processing an object to be processed with the plasma is 100 ° C. or less.
  4. 　前記薄膜が、前記被処理体の表面のシリコンが酸化されたシリコン酸化膜である請求項１に記載のプラズマ処理方法。 2. The plasma processing method according to claim 1, wherein the thin film is a silicon oxide film in which silicon on a surface of the object to be processed is oxidized.
  5. 　前記薄膜が、前記被処理体の表面のシリコンが窒化されたシリコン窒化膜である請求項１に記載のプラズマ処理方法。 2. The plasma processing method according to claim 1, wherein the thin film is a silicon nitride film in which silicon on the surface of the object to be processed is nitrided.
  6. 　前記プラズマ処理装置は、被処理体を収容する前記処理容器と、
    　前記処理容器の内部に配置され、前記被処理体を載置する載置面を有する載置台と、
    　前記処理容器内に処理ガスを供給するガス供給機構と、
    　前記マイクロ波を生成すると共に、該マイクロ波を複数の経路に分配して出力するマイクロ波出力部と、
    　前記マイクロ波出力部から出力された複数のマイクロ波をそれぞれ前記処理容器内に導入する複数のアンテナ部と、
    　前記複数のアンテナ部にそれぞれ対応して設けられて前記マイクロ波出力部と前記処理容器内との間のインピーダンスを整合させる複数のチューナと、
    　前記処理容器の上部に配置され、複数の開口部を有する導電性部材と、
    　前記複数の開口部に嵌合し、前記処理容器内に前記マイクロ波を透過させて導入させる複数のマイクロ波透過窓と、
    を備え、
    　前記複数のマイクロ波透過窓からそれぞれ前記処理容器内に導入した前記複数のマイクロ波によって前記プラズマを生成するものである請求項１に記載のプラズマ処理方法。     The plasma processing apparatus includes the processing container for storing an object to be processed;
    A mounting table disposed inside the processing container and having a mounting surface on which the object to be processed is mounted;
    A gas supply mechanism for supplying a processing gas into the processing container;
    A microwave output unit that generates the microwave and distributes and outputs the microwave to a plurality of paths;
    A plurality of antenna units for introducing a plurality of microwaves output from the microwave output unit into the processing vessel, respectively;
    A plurality of tuners provided corresponding to the plurality of antenna units, respectively, to match impedances between the microwave output unit and the inside of the processing container;
    A conductive member disposed at an upper portion of the processing container and having a plurality of openings;
    A plurality of microwave transmission windows that fit into the plurality of openings and allow the microwaves to pass through the processing vessel;
    With
    The plasma processing method according to claim 1, wherein the plasma is generated by the plurality of microwaves introduced into the processing container from the plurality of microwave transmission windows.
  7. 　前記複数のマイクロ波により前記プラズマを着火するときの前記マイクロ波のパワーの合計は、前記プラズマにより被処理体を処理するときの前記マイクロ波のパワーの合計よりも大きく、
    　前記複数のマイクロ波により前記プラズマを着火するときには前記インピーダンスの整合を行わず、前記プラズマにより被処理体を処理するときに前記インピーダンスの整合を行う請求項６に記載のプラズマ処理方法。     The total power of the microwaves when the plasma is ignited by the plurality of microwaves is greater than the total power of the microwaves when the object is processed by the plasma,
    The plasma processing method according to claim 6, wherein the impedance matching is not performed when the plasma is ignited by the plurality of microwaves, and the impedance matching is performed when the object to be processed is processed by the plasma.
  8. 　前記マイクロ波出力部から、前記複数のマイクロ波を、前記プラズマを着火させる第１のパワーで供給して前記プラズマを着火するステップと、
    　前記マイクロ波のパワーを前記第１のパワーよりも低い第２のパワーに変更するステップと、
    　前記第２のパワーの状態で前記インピーダンスの整合を行うステップと、
    を含む請求項６に記載のプラズマ処理方法。     Supplying the plurality of microwaves from the microwave output unit with a first power for igniting the plasma to ignite the plasma; and
    Changing the power of the microwave to a second power lower than the first power;
    Matching the impedance in the second power state;
    The plasma processing method of Claim 6 containing this.
  9. 　前記複数のマイクロ波透過窓は、前記導電性部材における中央部分に配置された１つの中心マイクロ波透過窓と、前記中心マイクロ波透過窓を囲むように、前記中央部分よりも外側に配置された少なくとも６つの外側マイクロ波透過窓とを有している請求項６に記載のプラズマ処理方法。 The plurality of microwave transmission windows are disposed outside the central portion so as to surround one central microwave transmission window disposed in the central portion of the conductive member and the central microwave transmission window. The plasma processing method according to claim 6, comprising at least six outer microwave transmission windows.
  10. 　前記プラズマにより被処理体を処理する処理温度が、１００℃以下である請求項２に記載のプラズマ処理方法。 The plasma processing method according to claim 2, wherein a processing temperature for processing an object to be processed by the plasma is 100 ° C. or less.
  11. 　前記薄膜が、前記被処理体の表面のシリコンが酸化されたシリコン酸化膜である請求項２に記載のプラズマ処理方法。 3. The plasma processing method according to claim 2, wherein the thin film is a silicon oxide film in which silicon on the surface of the object to be processed is oxidized.
  12. 　前記薄膜が、前記被処理体の表面のシリコンが窒化されたシリコン窒化膜である請求項２に記載のプラズマ処理方法。 3. The plasma processing method according to claim 2, wherein the thin film is a silicon nitride film in which silicon on the surface of the object to be processed is nitrided.
  13. 　前記プラズマ処理装置は、被処理体を収容する前記処理容器と、
    　前記処理容器の内部に配置され、前記被処理体を載置する載置面を有する載置台と、
    　前記処理容器内に処理ガスを供給するガス供給機構と、
    　前記マイクロ波を生成すると共に、該マイクロ波を複数の経路に分配して出力するマイクロ波出力部と、
    　前記マイクロ波出力部から出力された複数のマイクロ波をそれぞれ前記処理容器内に導入する複数のアンテナ部と、
    　前記複数のアンテナ部にそれぞれ対応して設けられて前記マイクロ波出力部と前記処理容器内との間のインピーダンスを整合させる複数のチューナと、
    　前記処理容器の上部に配置され、複数の開口部を有する導電性部材と、
    　前記複数の開口部に嵌合し、前記処理容器内に前記マイクロ波を透過させて導入させる複数のマイクロ波透過窓と、
    を備え、
    　前記複数のマイクロ波透過窓からそれぞれ前記処理容器内に導入した前記複数のマイクロ波によって前記プラズマを生成するものである請求項２に記載のプラズマ処理方法。     The plasma processing apparatus includes the processing container for storing an object to be processed;
    A mounting table disposed inside the processing container and having a mounting surface on which the object to be processed is mounted;
    A gas supply mechanism for supplying a processing gas into the processing container;
    A microwave output unit that generates the microwave and distributes and outputs the microwave to a plurality of paths;
    A plurality of antenna units for introducing a plurality of microwaves output from the microwave output unit into the processing vessel, respectively;
    A plurality of tuners provided corresponding to the plurality of antenna units, respectively, to match impedances between the microwave output unit and the inside of the processing container;
    A conductive member disposed at an upper portion of the processing container and having a plurality of openings;
    A plurality of microwave transmission windows that fit into the plurality of openings and allow the microwaves to pass through the processing vessel;
    With
    The plasma processing method according to claim 2, wherein the plasma is generated by the plurality of microwaves introduced into the processing container from the plurality of microwave transmission windows.
  14. 　前記複数のマイクロ波により前記プラズマを着火するときの前記マイクロ波のパワーの合計は、前記プラズマにより被処理体を処理するときの前記マイクロ波のパワーの合計よりも大きく、
    　前記複数のマイクロ波により前記プラズマを着火するときには前記インピーダンスの整合を行わず、前記プラズマにより被処理体を処理するときに前記インピーダンスの整合を行う請求項１３に記載のプラズマ処理方法。     The total power of the microwaves when the plasma is ignited by the plurality of microwaves is greater than the total power of the microwaves when the object is processed by the plasma,
    The plasma processing method according to claim 13, wherein the impedance matching is not performed when the plasma is ignited by the plurality of microwaves, and the impedance matching is performed when the object to be processed is processed by the plasma.
  15. 　前記マイクロ波出力部から、前記複数のマイクロ波を、前記プラズマを着火させる第１のパワーで供給して前記プラズマを着火するステップと、
    　前記マイクロ波のパワーを前記第１のパワーよりも低い第２のパワーに変更するステップと、
    　前記第２のパワーの状態で前記インピーダンスの整合を行うステップと、
    を含む請求項１３に記載のプラズマ処理方法。     Supplying the plurality of microwaves from the microwave output unit with a first power for igniting the plasma to ignite the plasma; and
    Changing the power of the microwave to a second power lower than the first power;
    Matching the impedance in the second power state;
    The plasma processing method of Claim 13 containing these.
  16. 　前記複数のマイクロ波透過窓は、前記導電性部材における中央部分に配置された１つの中心マイクロ波透過窓と、前記中心マイクロ波透過窓を囲むように、前記中央部分よりも外側に配置された少なくとも６つの外側マイクロ波透過窓とを有している請求項１３に記載のプラズマ処理方法。 The plurality of microwave transmission windows are disposed outside the central portion so as to surround one central microwave transmission window disposed in the central portion of the conductive member and the central microwave transmission window. The plasma processing method according to claim 13, comprising at least six outer microwave transmission windows.
  17. 　複数のマイクロ波により処理容器内にプラズマを生成させて被処理体の表面に薄膜を形成するプラズマ処理装置であって、
    　被処理体を収容する処理容器と、
    　前記処理容器の内部に配置され、前記被処理体を載置する載置面を有する載置台と、
    　前記処理容器内に処理ガスを供給するガス供給機構と、
    　前記マイクロ波を生成すると共に、該マイクロ波を複数の経路に分配して出力するマイクロ波出力部と、
    　前記マイクロ波出力部から出力された複数のマイクロ波をそれぞれ前記処理容器内に導入する複数のアンテナ部と、
    　前記複数のアンテナ部にそれぞれ対応して設けられて前記マイクロ波出力部と前記処理容器内との間のインピーダンスを整合させる複数のチューナと、
    　前記処理容器の上部に配置され、複数の開口部を有する導電性部材と、
    　前記複数の開口部に嵌合し、前記処理容器内に前記マイクロ波を透過させて導入させる複数のマイクロ波透過窓と、
    　前記処理容器内で前記複数のマイクロ波によりプラズマを着火するときのマイクロ波のパワーの合計が、前記被処理体の面積当たり１Ｗ／ｃｍ２以下となるように、前記複数のマイクロ波透過窓から、それぞれ前記処理容器内にマイクロ波を導入することにより、前記薄膜の膜厚を１ｎｍ以下に制御する制御部と、
    を備えたことを特徴とするプラズマ処理装置。
          A plasma processing apparatus for generating plasma in a processing container by a plurality of microwaves to form a thin film on the surface of an object to be processed,
    A processing container for storing an object to be processed;
    A mounting table disposed inside the processing container and having a mounting surface on which the object to be processed is mounted;
    A gas supply mechanism for supplying a processing gas into the processing container;
    A microwave output unit that generates the microwave and distributes and outputs the microwave to a plurality of paths;
    A plurality of antenna units for introducing a plurality of microwaves output from the microwave output unit into the processing vessel, respectively;
    A plurality of tuners provided corresponding to the plurality of antenna units, respectively, for matching impedance between the microwave output unit and the inside of the processing container;
    A conductive member disposed at an upper portion of the processing container and having a plurality of openings;
    A plurality of microwave transmission windows that fit into the plurality of openings and allow the microwaves to pass through the processing vessel;
    From the plurality of microwave transmission windows, the total power of the microwaves when the plasma is ignited by the plurality of microwaves in the processing container is 1 W / cm 2 or less per area of the object to be processed. A control unit for controlling the film thickness of the thin film to 1 nm or less by introducing a microwave into the processing container,
    A plasma processing apparatus comprising:
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