WO2020145002A1 - Substrate processing device and substrate processing method - Google Patents

Substrate processing device and substrate processing method Download PDF

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Publication number
WO2020145002A1
WO2020145002A1 PCT/JP2019/048272 JP2019048272W WO2020145002A1 WO 2020145002 A1 WO2020145002 A1 WO 2020145002A1 JP 2019048272 W JP2019048272 W JP 2019048272W WO 2020145002 A1 WO2020145002 A1 WO 2020145002A1
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WIPO (PCT)
Prior art keywords
unit
dissolved
chemical liquid
nitrogen gas
nitrogen concentration
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PCT/JP2019/048272
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French (fr)
Japanese (ja)
Inventor
貴士 藪田
一剛 水本
秀俊 中尾
史洋 上村
秀雄 中野
郁雄 須中
政俊 笠原
Original Assignee
東京エレクトロン株式会社
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Publication of WO2020145002A1 publication Critical patent/WO2020145002A1/en

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    • 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
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
    • 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
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
    • H01L21/308—Chemical or electrical treatment, e.g. electrolytic etching using masks

Definitions

  • the present disclosure relates to a substrate processing apparatus and a substrate processing method.
  • the substrate processing method described in Patent Document 1 etches the polysilicon film formed on the substrate by discharging a TMAH (tetramethylammonium hydroxide)-containing chemical solution in which oxygen gas is dissolved from a chemical solution nozzle.
  • This substrate processing method measures the dissolved oxygen concentration of a TMAH-containing chemical solution.
  • nitrogen gas is dissolved in the TMAH-containing chemical solution to reduce the etching rate.
  • oxygen gas is dissolved in the TMAH-containing chemical solution to increase the etching rate.
  • One aspect of the present disclosure provides a technique capable of accurately controlling the etching rate of a polysilicon film or an amorphous silicon film with an alkaline chemical solution.
  • a substrate processing apparatus A processing unit for etching the polysilicon film or the amorphous silicon film formed on the substrate with an alkaline chemical solution in which nitrogen gas is previously dissolved, A measuring unit for measuring the dissolved nitrogen concentration of the chemical solution, A dissolving portion for dissolving nitrogen gas in the chemical solution, And a control unit that determines the amount of nitrogen gas to be dissolved in the chemical liquid per unit time by the dissolution unit based on the dissolved nitrogen concentration measured by the measurement unit.
  • FIG. 1 is a diagram showing a substrate processing apparatus according to an embodiment.
  • FIG. 2 is a diagram illustrating a processing unit according to an embodiment.
  • FIG. 3 is a flowchart showing a part of the substrate processing method according to the embodiment.
  • FIG. 4 is a flowchart showing another part of the substrate processing method according to the embodiment.
  • FIG. 5 is a flowchart showing an example of the process of determining the dissolution amount.
  • FIG. 6 is a flowchart showing yet another part of the substrate processing method according to the embodiment.
  • FIG. 7 is a flowchart showing an example of a step of determining the set value of the dissolved nitrogen concentration.
  • FIG. 8 is a diagram showing an example of the upstream recovery line dissolving unit shown in FIG. 1.
  • 9 is a figure which shows the modification of the dissolving
  • the same or corresponding components are designated by the same or corresponding reference numerals, and description thereof may be omitted.
  • the lower side means the lower side in the vertical direction
  • the upper side means the upper side in the vertical direction.
  • FIG. 1 is a diagram showing a substrate processing apparatus according to an embodiment.
  • the substrate processing apparatus 1 includes a processing unit 10, for example.
  • the processing unit 10 etches the polysilicon film formed on the substrate 2 (see FIG. 2) with the alkaline chemical liquid 3 in which nitrogen gas is dissolved in advance.
  • the chemical solution 3 may etch an amorphous silicon film formed instead of the polysilicon film.
  • the amorphous silicon film is also etched similarly to the polysilicon film. Both the polysilicon film and the amorphous silicon film may be oxidized by the dissolved gas in the chemical liquid 3. The oxidation with the dissolved gas will be described later.
  • FIG. 2 is a diagram showing a processing unit according to one embodiment.
  • the processing unit 10 includes, for example, a processing container 11, a substrate holding unit 13, a rotation driving mechanism 16, a nozzle 20, and a cup 25.
  • the processing unit 10 is a single-wafer type that processes the substrates 2 one by one, but may be a batch type that simultaneously processes a plurality of substrates 2.
  • the processing unit 10 has a processing container 11 whether it is a single-wafer type or a batch type.
  • the processing container 11 accommodates the substrate 2 inside.
  • the processing container 11 has a gate for loading the substrate 2 into the processing container 11 from the outside of the processing container 11, and a gate valve for opening and closing the gate.
  • the substrate 2 processed inside the processing container 11 is carried out of the processing container 11 through the gate.
  • the substrate holding unit 13 horizontally holds the substrate 2 loaded in the processing container 11.
  • the substrate holding unit 13 holds the substrate 2 horizontally with the surface of the substrate 2 on which the polysilicon film is formed facing upward.
  • the substrate holding unit 13 is a mechanical chuck in FIG. 2, it may be a vacuum chuck or an electrostatic chuck.
  • the substrate holding part 13 has a rotating shaft part 14 arranged vertically.
  • the rotating shaft portion 14 is rotatably supported by a bearing 15.
  • the rotation drive mechanism 16 rotates the substrate holding unit 13.
  • the rotary drive mechanism 16 includes a rotary motor 17 and a transmission mechanism 18 that transmits the rotary motion of the rotary motor 17 to the rotary shaft portion 14.
  • the transmission mechanism 18 includes, for example, a pulley and a timing belt.
  • the transmission mechanism 18 may be composed of a gear or the like.
  • the nozzle 20 supplies the alkaline chemical liquid 3 in which nitrogen gas is dissolved in advance to the substrate 2 held by the substrate holding portion 13.
  • the nozzle 20 has a discharge port 21 for discharging the chemical liquid 3.
  • the nozzle 20 is arranged above the substrate 2 with the ejection port 21 facing downward.
  • the nozzle 20 is movable in the radial direction of the substrate 2 above the substrate 2.
  • the nozzle 20 supplies the chemical liquid 3 to the central portion of the substrate 2 rotating together with the substrate holding unit 13, for example.
  • the chemical liquid 3 supplied to the central portion of the rotating substrate 2 wets and spreads over the entire upper surface of the substrate 2 due to a centrifugal force to form a liquid film.
  • the liquid film etches the polysilicon film.
  • the chemical liquid 3 is a TMAH-containing chemical liquid containing TMAH (tetramethylammonium hydroxide), for example.
  • TMAH tetramethylammonium hydroxide
  • the chemical liquid 3 is the TMAH-containing chemical liquid in this embodiment, it may be any liquid as long as it etches the polysilicon film.
  • the drug solution 3 may be an ammonia solution or a choline solution.
  • the nozzle 20 may discharge a rinse liquid and a drying liquid in addition to the chemical liquid 3 for etching.
  • the liquid that processes the substrate 2, such as the chemical liquid 3, the rinse liquid, and the drying liquid, is also referred to as a “processing liquid”.
  • One nozzle 20 may eject a plurality of types of treatment liquids in order, or a plurality of nozzles 20 may eject different treatment liquids.
  • the rinse liquid is not particularly limited, but DIW (deionized water) is used, for example.
  • the rinse liquid is used after the chemical liquid 3.
  • the rinsing liquid wets and spreads from the central portion of the substrate 2 to the outer peripheral portion of the substrate 2 by the centrifugal force while replacing the chemical liquid 3 to form a liquid film.
  • the rinse liquid is not particularly limited, but water such as DIW (deionized water) is used, for example.
  • the drying liquid is not particularly limited as long as it is more volatile than the rinse liquid, but IPA (isopropyl alcohol) is used, for example. While substituting the rinse liquid, the drying liquid wets and spreads from the central portion of the substrate 2 to the outer peripheral portion of the substrate 2 by a centrifugal force, forming a liquid film.
  • the drying liquid is not particularly limited, but an organic solvent such as IPA (isopropyl alcohol) is used.
  • the nozzle 20 may eject a chemical liquid different from the chemical liquid 3 for etching, for example, a chemical liquid for cleaning may be ejected before the chemical liquid 3 for etching.
  • a chemical liquid for cleaning may be ejected before the chemical liquid 3 for etching.
  • the contaminants on the polysilicon film before etching can be removed with a cleaning chemical.
  • the cleaning chemicals include DHF (dilute hydrofluoric acid), SC-1 (aqueous solution containing ammonium hydroxide and hydrogen peroxide), or SC-2 (aqueous solution containing hydrogen chloride and hydrogen peroxide). Can be mentioned.
  • the cup 25 is arranged so as to surround the substrate holding unit 13, and collects the processing liquid such as the chemical liquid 3 scattered from the substrate 2 rotating with the substrate holding unit 13.
  • a drain pipe 26 and an exhaust pipe 27 are provided at the bottom of the cup 25. The drain pipe 26 discharges the processing liquid in the cup 25, and the exhaust pipe 27 discharges the gas in the cup 25.
  • the cup 25 holds the bearing 15 that rotatably supports the substrate holding unit 13, and does not rotate together with the substrate holding unit 13. Although the cup 25 does not rotate with the substrate holding unit 13 in this embodiment, it may rotate with the substrate holding unit 13.
  • the substrate processing apparatus 1 includes a control unit 90 as shown in FIG.
  • the control unit 90 is configured by, for example, a computer, and includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as a memory.
  • the storage medium 92 stores programs that control various processes executed in the substrate processing apparatus 1.
  • the control unit 90 controls the operation of the substrate processing apparatus 1 by causing the CPU 91 to execute the program stored in the storage medium 92.
  • the controller 90 also includes an input interface 93 and an output interface 94. In the control unit 90, the input interface 93 receives a signal from the outside, and the output interface 94 transmits the signal to the outside.
  • the program may be stored in a computer-readable storage medium, and may be installed in the storage medium 92 of the control unit 90 from the storage medium.
  • Examples of the computer-readable storage medium include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical desk (MO), and a memory card.
  • the program may be downloaded from the server via the Internet and installed in the storage medium 92 of the control unit 90.
  • FIG. 3 is a flowchart showing a part of the substrate processing method according to the embodiment. Steps S101 to S106 shown in FIG. 3 are performed under the control of the controller 90, and are repeatedly performed by changing the substrate 2.
  • the substrate processing method has a step S101 of loading the substrate 2 into the processing container 11.
  • the transfer device carries the substrate 2 into the processing container 11 from the outside of the processing container 11, and transfers the carried-in substrate 2 to the substrate holding unit 13.
  • the substrate holding unit 13 holds the substrate 2 horizontally with the surface of the substrate 2 on which the polysilicon film is formed facing upward.
  • the substrate processing method includes a step S102 of supplying the chemical liquid 3 to the upper surface of the substrate 2.
  • the chemical liquid 3 is supplied from above to the central portion of the substrate 2 in which the nozzle 20 is rotating together with the substrate holding portion 13.
  • the supplied chemical liquid 3 wets and spreads over the entire upper surface of the substrate 2 due to a centrifugal force to form a liquid film.
  • the liquid film etches the polysilicon film formed on the substrate 2.
  • the substrate processing method has a step S103 of supplying a rinse liquid to the upper surface of the substrate 2.
  • the rinse liquid is supplied from above to the central portion of the substrate 2 in which the nozzle 20 is rotating together with the substrate holding portion 13.
  • the supplied rinsing liquid replaces the chemical liquid 3 and wets and spreads over the entire upper surface of the substrate 2 by a centrifugal force to form a liquid film.
  • the chemical liquid 3 is replaced with the rinse liquid and removed.
  • the substrate processing method has a step S104 of supplying a drying liquid onto the upper surface of the substrate 2.
  • the drying liquid is supplied from above to the central portion of the substrate 2 in which the nozzle 20 is rotating together with the substrate holding portion 13.
  • the supplied drying liquid replaces the rinsing liquid and spreads over the entire upper surface of the substrate 2 by centrifugal force to form a liquid film.
  • the rinse liquid is replaced with a dry liquid and removed.
  • the substrate processing method includes a step S105 of drying the substrate 2.
  • the nozzle 20 stops the discharge of the drying liquid, and the rotation drive mechanism 16 rotates the substrate 2 together with the substrate holding unit 13.
  • the drying liquid remaining on the substrate 2 is shaken off from the substrate 2 by the centrifugal force. Thereby, the substrate 2 is dried.
  • the substrate processing method has a step S106 of unloading the substrate 2 from the inside of the processing container 11 to the outside of the processing container 11.
  • step S106 the substrate holding unit 13 first releases the holding of the substrate 2.
  • the transfer device receives the substrate 2 from the substrate holder 13 and carries the received substrate 2 out of the processing container 11 to the outside of the processing container 11.
  • step S104 of supplying the drying liquid may not be performed.
  • step S105 of drying the substrate 2 the nozzle 20 stops discharging the rinse liquid, and the rotation drive mechanism 16 rotates the substrate 2 together with the substrate holding unit 13.
  • the rinse liquid remaining on the substrate 2 is shaken off from the substrate 2 by the centrifugal force. Thereby, the substrate 2 is dried.
  • the substrate processing apparatus 1 includes a storage unit 30 that stores the chemical liquid 3, and a supply line 31 that supplies the chemical liquid 3 from the storage unit 30 to the processing unit 10.
  • the storage unit 30 is, for example, a tank that stores the chemical liquid 3.
  • the supply line 31 has, for example, a circulation line 32, a first branch line 33, and a second branch line 34.
  • the circulation line 32 returns the drug solution 3 taken out from the storage section 30 to the storage section 30.
  • the upstream end 32a of the circulation line 32 is connected to the storage part 30, and the downstream end 32b of the circulation line 32 is also connected to the storage part 30.
  • a pump 35 that sends out the chemical liquid 3, a filter 36 that collects foreign substances in the chemical liquid 3, and a heater 37 that heats the chemical liquid 3 are arranged in the circulation line 32. Under the control of the controller 90, the heater 37 heats the chemical liquid 3 so that the temperature measured by a thermometer (not shown) reaches the set temperature. The temperature of the chemical liquid 3 supplied to the processing unit 10 can be maintained at the set temperature.
  • the order of the pump 35, the filter 36, and the heater 37 is not limited to the order shown in FIG.
  • the first branch line 33 branches from the first branch point 38 of the circulation line 32 and extends to the processing unit 10.
  • the upstream end of the first branch line 33 is connected to the first branch point 38 of the circulation line 32, and the downstream end of the first branch line 33 is connected to the processing unit 10.
  • the chemical liquid 3 taken out from the storage unit 30 flows from the upstream end 32 a of the circulation line 32 to the first branch point 38 of the circulation line 32, and then passes through the first branch line 33 and is supplied to the processing unit 10.
  • the first branch line 33 is provided for each processing unit 10.
  • An opening/closing valve 39 that opens and closes the flow path of the first branch line 33 is provided in the middle of the first branch line 33. The opening and closing of the on-off valve 39 is controlled by the control unit 90.
  • the second branch line 34 branches from the second branch point 40 of the circulation line 32 and extends to the storage section 30.
  • the second branch point 40 is arranged closer to the upstream end 32a of the circulation line 32 than all the first branch points 38.
  • the upstream end of the second branch line 34 is connected to the second branch point 40 of the circulation line 32, and the downstream end of the second branch line 34 is connected to the storage section 30.
  • the chemical liquid 3 taken out from the storage section 30 flows from the upstream end 32 a of the circulation line 32 to the second branch point 40 of the circulation line 32, and then passes through the second branch line 34 and is returned to the storage section 30.
  • a dissolved nitrogen concentration meter 51 described later is arranged in the middle of the second branch line 34.
  • the substrate processing apparatus 1 includes a recovery line 41 that returns the chemical liquid 3 from the processing unit 10 to the storage unit 30.
  • the recovery line 41 has a main line 42 and a sub line 43.
  • the main line 42 extends from the one processing unit 10 to the storage unit 30.
  • the sub line 43 extends from the other one processing unit 10 to the middle of the main line 42.
  • the number of the sub-lines 43 is one in FIG. 1, it may be plural.
  • the number of sub-lines 43 may be one less than the number of processing units 10.
  • the chemical liquid 3 discharged from the nozzle 20 passes through the recovery line 41 and is returned to the storage unit 30. The amount of the chemical solution 3 to be discarded can be reduced. It should be noted that part of the chemical liquid 3 discharged from the nozzle 20 may be discarded without being returned to the storage section 30.
  • the etching rate ER of the polysilicon film by the chemical liquid 3 is determined by the dissolved oxygen concentration of the chemical liquid 3 and the like.
  • Dissolved oxygen is molecular oxygen (O 2 ) dissolved in a liquid. The larger the dissolved oxygen concentration (unit: mg/L), the more easily the polysilicon film is oxidized and the more easily the oxide film is formed.
  • the etching rate ER of the polysilicon film decreases as the oxidation of the polysilicon film progresses. This is because the TMAH-containing chemical solution is not good at etching the oxide film.
  • the etching rate ER of the polysilicon film increases as the oxidation of the polysilicon film progresses. This is because the ammonia solution and the choline solution are good at etching the oxide film.
  • the chemical solution 3 is an ammonia solution or a choline solution
  • medical solution 3 is measured.
  • Oxygen (O 2 ) is one of the dissolved gases that oxidize the polysilicon film, but not all.
  • ozone (O 3 ) is also a dissolved gas that oxidizes the polysilicon film.
  • the substrate processing apparatus 1 of the present embodiment measures the dissolved nitrogen concentration DN (unit: mg/L) of the chemical liquid 3.
  • the difference ⁇ DN obtained by subtracting the measured dissolved nitrogen concentration DN from the saturated dissolved nitrogen concentration represents the partial pressure of all dissolved gases other than nitrogen. All dissolved gases other than nitrogen include all dissolved gases that contribute to oxidation.
  • the saturated dissolved nitrogen concentration is constant, the smaller the measured dissolved nitrogen concentration DN, the larger the difference ⁇ DN.
  • the larger the total partial pressure of all dissolved gases that contribute to oxidation the greater the total concentration of all dissolved gases that contribute to oxidation. Therefore, the smaller the measured dissolved nitrogen concentration DN, the larger the total concentration of all dissolved gases that contribute to oxidation.
  • the substrate processing apparatus 1 includes a measuring unit 50 that measures the dissolved nitrogen concentration DN of the chemical liquid 3 and a dissolving unit 60 that dissolves nitrogen gas in the chemical liquid 3.
  • the control unit 90 determines the amount of nitrogen gas to be dissolved in the chemical liquid 3 per unit time by the dissolving unit 60 based on the dissolved nitrogen concentration DN measured by the measuring unit 50.
  • concentration DN of dissolved nitrogen that does not contribute to oxidation
  • the total concentration of all dissolved gases that contribute to oxidation can be controlled, so that the etching rate ER of the polysilicon film by the chemical solution 3 can be controlled accurately.
  • the etching rate ER of the polysilicon film with the chemical solution 3 will be simply referred to as “etching rate ER”.
  • the measurement unit 50 has a dissolved nitrogen concentration meter 51 that measures the dissolved nitrogen concentration DN of the chemical liquid 3.
  • the dissolved nitrogen concentration meter 51 generates hydrogen radicals by irradiating the chemical liquid 3 with ultrasonic waves, for example.
  • the reaction of hydrogen radicals with dissolved nitrogen produces nitrogen compounds (eg NO X ⁇ , NH 4 + ).
  • the dissolved nitrogen concentration meter 51 measures the amount of ions derived from dissolved nitrogen with a resistivity meter and calculates the dissolved nitrogen concentration DN based on the measured amount of ions.
  • the dissolved nitrogen concentration meter 51 transmits a signal indicating the measurement result to the control unit 90.
  • the dissolved nitrogen concentration meter 51 may be arranged in either the supply line 31 or the recovery line 41, or both, but in the present embodiment, it is arranged in the middle of the supply line 31.
  • the supply line 31 supplies the chemical liquid 3 from the storage unit 30 to the processing unit 10.
  • the supply line 31 has the circulation line 32 in which the heater 37 is arranged and the first branch line 33 for the purpose of controlling the temperature of the chemical liquid 3.
  • the circulation line 32 returns the chemical liquid 3 taken out from the storage section 30 to the storage section 30.
  • the upstream end 32a of the circulation line 32 is connected to the storage part 30, and the downstream end 32b of the circulation line 32 is also connected to the storage part 30.
  • the first branch line 33 branches from the first branch point 38 of the circulation line 32 and extends to the processing unit 10.
  • the first branch line 33 is provided for each processing unit 10.
  • the dissolved nitrogen concentration meter 51 is arranged closer to the upstream end 32a of the circulation line 32 than all the first branch points 38 of the circulation line 32.
  • the dissolved nitrogen concentration DN of the chemical liquid 3 at the time of etching the polysilicon film can be controlled, and the etching rate ER can be controlled accurately.
  • the dissolved nitrogen concentration meter 51 is arranged on the upstream end 32a side of the circulation line 32 with respect to all the first branch points 38 of the circulation line 32.
  • the dissolved nitrogen concentration meter 51 is arranged in the second branch line 34.
  • the second branch line 34 branches from the second branch point 40 of the circulation line 32 and extends to the storage section 30.
  • the dissolved nitrogen concentration meter 51 may be arranged on the upstream end 32a side of the circulation line 32 with respect to all the first branch points 38 of the circulation line 32, or may be arranged on the circulation line 32.
  • the dissolving section 60 has a dissolving unit that dissolves nitrogen gas in the chemical liquid 3. By dissolving nitrogen gas in the chemical liquid 3, the dissolved nitrogen concentration DN of the chemical liquid 3 can be increased. The dissolved nitrogen concentration DN of the chemical liquid 3 never exceeds the saturated dissolved nitrogen concentration of the chemical liquid 3.
  • the nitrogen gas one having a high purity is used, for example, one having a purity of 99.9% by mass or more is used.
  • the dissolution unit for example, a bubbling unit, a purge unit or a mixing unit is used.
  • the bubbling unit has a bubbling pipe provided with a discharge port for discharging nitrogen gas inside the chemical liquid 3 stored in the container.
  • the purge unit has a purge pipe provided with a discharge port for discharging nitrogen gas in an upper space formed above the chemical liquid 3 stored in the container.
  • the purge pipe discharges nitrogen gas to replace the gas in the upper space of the container with nitrogen gas.
  • the mixing unit has a gas pipe for supplying nitrogen gas into the chemical liquid pipe through which the chemical liquid 3 flows, and a stirring blade for stirring the nitrogen gas and the chemical liquid 3 inside the chemical liquid pipe.
  • the dissolution unit only needs to have a function of dissolving nitrogen gas in the chemical liquid 3, and may further have a function of dissolving oxygen gas in the chemical liquid 3.
  • the dissolved oxygen concentration of the chemical liquid 3 can be increased.
  • the dissolved oxygen partial pressure of the chemical liquid 3 increases, so that the dissolved nitrogen partial pressure of the chemical liquid 3 decreases.
  • the dissolved nitrogen concentration DN of the chemical liquid 3 becomes smaller.
  • the oxygen gas is supplied as air, for example. As air, dry air having a dew point of -10°C or lower is used.
  • the dissolving unit dissolves oxygen gas in the chemical liquid 3 in the same manner as nitrogen gas.
  • the bubbling unit has a bubbling pipe provided with a discharge port for discharging oxygen gas inside the chemical liquid 3 stored in the container.
  • the purge unit has a purge pipe provided with a discharge port for discharging oxygen gas in an upper space formed above the chemical liquid 3 stored in the container.
  • the purge pipe discharges oxygen gas to replace the gas in the upper space of the container with oxygen gas.
  • the mixing unit has a gas pipe for supplying oxygen gas into the chemical liquid pipe through which the chemical liquid 3 flows, and a stirring blade for stirring the oxygen gas and the chemical liquid 3 inside the chemical liquid pipe.
  • the dissolution unit is installed in one or more selected from the storage unit 30, the supply line 31, the processing unit 10, and the recovery line 41. Note that a plurality of melting units may be installed in one selected from these. For example, both the bubbling unit and the purging unit may be installed in the storage unit 30.
  • the dissolving section 60 has, for example, a storing section dissolving unit 61, recovery line dissolving units 64A and 64B, and a processing section dissolving unit 67.
  • the storage unit dissolution unit 61 is a dissolution unit installed in the storage unit 30.
  • the recovery line dissolution units 64A and 64B are dissolution units installed in the recovery line 41.
  • the processing unit dissolution unit 67 is a dissolution unit installed in the processing unit 10.
  • the storage unit dissolution unit 61 supplies nitrogen gas to the storage unit 30 to dissolve the nitrogen gas in the chemical liquid 3.
  • the control unit 90 determines the amount of nitrogen gas to be dissolved in the chemical liquid 3 per unit time by the storage unit dissolution unit 61 based on the dissolved nitrogen concentration DN measured by the measurement unit 50.
  • the storage unit dissolution unit 61 includes a bubbling pipe 62.
  • the bubbling pipe 62 generates nitrogen gas bubbles inside the chemical liquid 3 by discharging nitrogen gas into the chemical liquid 3.
  • the amount of nitrogen gas used can be reduced as compared with the case where a purge pipe is used instead of the bubbling pipe 62. This is because the nitrogen gas and the chemical liquid 3 can be efficiently brought into contact with each other before the nitrogen gas is exhausted from the inside of the storage portion 30 to the outside of the storage portion 30.
  • a flow rate adjusting valve 72 is arranged in the middle of the bubbling pipe 62.
  • the flow rate adjusting valve 72 adjusts the flow rate of the nitrogen gas discharged from the bubbling pipe 62 into the chemical liquid 3 under the control of the control unit 90.
  • the control unit 90 determines the flow rate of the nitrogen gas discharged from the bubbling pipe 62 into the chemical liquid 3 based on the dissolved nitrogen concentration DN measured by the measuring unit 50. As the flow rate of nitrogen gas increases, the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time increases, and the dissolved nitrogen concentration DN of the chemical liquid 3 increases. The dissolved nitrogen concentration DN never exceeds the saturated dissolved nitrogen concentration.
  • the storage unit dissolution unit 61 supplies oxygen gas to the storage unit 30 under the control of the control unit 90 to dissolve the oxygen gas in the chemical liquid 3.
  • the control unit 90 determines the amount of oxygen gas to be dissolved in the chemical liquid 3 per unit time by the storage unit dissolution unit 61 based on the dissolved nitrogen concentration DN measured by the measurement unit 50.
  • the storage unit dissolution unit 61 includes a bubbling pipe 63.
  • the bubbling pipe 63 discharges oxygen gas into the chemical liquid 3 to generate bubbles of oxygen gas inside the chemical liquid 3.
  • the amount of oxygen gas used can be reduced as compared with the case where a purge pipe is used instead of the bubbling pipe 63. This is because the oxygen gas and the chemical liquid 3 can be efficiently brought into contact with each other before the oxygen gas is exhausted from the inside of the reservoir 30 to the outside of the reservoir 30.
  • a flow rate adjusting valve 73 is arranged in the middle of the bubbling pipe 63.
  • the flow rate adjusting valve 73 adjusts the flow rate of the oxygen gas discharged from the bubbling pipe 63 into the chemical liquid 3 under the control of the control unit 90.
  • the control unit 90 determines the flow rate of the oxygen gas discharged from the bubbling pipe 63 into the chemical liquid 3 based on the dissolved nitrogen concentration DN measured by the measurement unit 50. As the flow rate of oxygen gas increases, the amount of oxygen gas dissolved in the chemical liquid 3 per unit time increases, and the dissolved nitrogen concentration DN of the chemical liquid 3 decreases.
  • the storage unit dissolution unit 61 has a function of dissolving oxygen gas in the chemical liquid 3, but the technique of the present disclosure is not limited to this.
  • the recovery line dissolution units 64A and 64B may have a function of dissolving oxygen gas in the chemical liquid 3.
  • the processing unit dissolution unit 67 may have a function of dissolving oxygen gas in the chemical liquid 3.
  • the recovery line dissolution units 64A and 64B are provided in the main line 42 of the recovery line 41, as shown in FIG.
  • the one recovery line dissolution unit 64A is provided further upstream than the most upstream sub line 43.
  • the other recovery line dissolving unit 64B is provided further downstream than the most downstream side sub-line 43.
  • the recovery line dissolution unit 64A is, for example, a purge unit, as shown in FIG.
  • the recovery line dissolution unit 64A has a purge pipe 65.
  • the purge pipe 65 replaces the gas in the upper space of the recovery line 41 with the nitrogen gas by discharging the nitrogen gas into the upper space inside the recovery line 41.
  • a flow rate adjustment valve 66 is provided in the middle of the purge pipe 65.
  • the flow rate adjusting valve 66 adjusts the flow rate of the nitrogen gas discharged from the purge pipe 65 into the recovery line 41 under the control of the control unit 90. As the flow rate of nitrogen gas increases, the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time increases, and the dissolved nitrogen concentration DN of the chemical liquid 3 increases.
  • the recovery line dissolving units 64A and 64B supply nitrogen gas to the recovery line 41 to dissolve the nitrogen gas in the chemical liquid 3.
  • the control unit 90 determines the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time by the recovery line dissolution units 64A and 64B based on the dissolved nitrogen concentration DN measured by the measurement unit 50.
  • the chemical liquid 3 is discharged into the processing container 11 of the processing unit 10, passes through the recovery line 41 extending from the processing unit 10 to the storage unit 30, and returns to the storage unit 30. Unlike the supply line 31, the recovery line 41 does not always flow the chemical liquid 3. Since there is a space inside the recovery line 41, the oxygen gas in the space may dissolve in the chemical liquid 3. Therefore, while the chemical liquid 3 passes through the recovery line 41, the dissolved oxygen concentration of the chemical liquid 3 may increase and the dissolved nitrogen concentration DN of the chemical liquid 3 may decrease.
  • the recovery line dissolution units 64A and 64B dissolve nitrogen gas in the chemical liquid 3 in the middle of the recovery line 41.
  • the difference in the dissolved nitrogen concentration DN between the chemical liquid 3 returning from the recovery line 41 to the storage unit 30 and the chemical liquid 3 stored in advance in the storage unit 30 can be reduced. Therefore, the uniformity of the dissolved nitrogen concentration DN of the chemical liquid 3 inside the reservoir 30 can be improved.
  • the recovery line dissolution unit 64A is provided further upstream than the most upstream sub line 43. Since nitrogen gas can be supplied to the upstream portion of the recovery line 41, contact between the chemical liquid 3 flowing through the recovery line 41 and oxygen gas can be suppressed, and a decrease in the dissolved nitrogen concentration DN of the chemical liquid 3 can be suppressed.
  • the recovery line dissolution unit 64B is provided further downstream than the most downstream sub line 43. Since nitrogen gas can be supplied to the downstream portion of the recovery line 41, the once lowered dissolved nitrogen concentration DN can be returned to the original value again.
  • the downstream recovery line dissolution unit 64B discharges nitrogen gas into the recovery line 41 when the upstream recovery line dissolution unit 64A cannot sufficiently suppress the decrease in the dissolved nitrogen concentration DN of the chemical liquid 3. ..
  • the control unit 90 determines the amount of nitrogen gas to be dissolved in the chemical liquid 3 per unit time by the recovery line dissolution units 64A and 64B based on the dissolved nitrogen concentration DN measured by the dissolved nitrogen concentration meter 51.
  • the dissolved nitrogen concentration meter 51 is installed in the supply line 31 in the present embodiment, it may be installed in the recovery line 41.
  • the dissolved nitrogen concentration meter 51 is installed in the recovery line 41, the dissolved nitrogen concentration DN of the chemical liquid 3 in the recovery line 41 can be measured. Therefore, it is easy to reduce the difference in the dissolved nitrogen concentration DN between the chemical liquid 3 returning from the recovery line 41 to the storage portion 30 and the chemical liquid 3 stored in advance in the storage portion 30.
  • the dissolved nitrogen concentration meter 51 When installed in the recovery line 41, the dissolved nitrogen concentration meter 51 may be arranged upstream of the recovery line dissolution unit 64A, or may be disposed downstream of the recovery line dissolution unit 64B, It may be disposed between the two recovery line dissolution units 64A and 64B. In any case, it is easy to reduce the difference in the dissolved nitrogen concentration DN between the chemical liquid 3 returning from the recovery line 41 to the storage portion 30 and the chemical liquid 3 stored in advance in the storage portion 30.
  • the oxygen gas may dissolve in the chemical liquid 3 inside the processing container 11 of the processing unit 10.
  • the processing unit dissolution unit 67 is used in order to suppress a decrease in the dissolved nitrogen concentration DN inside the processing container 11.
  • the processing unit dissolution unit 67 supplies nitrogen gas into the processing container 11 to dissolve the nitrogen gas in the chemical liquid 3.
  • the control unit 90 determines the amount of nitrogen gas to be dissolved in the chemical liquid 3 per unit time by the processing unit dissolution unit 67 based on the dissolved nitrogen concentration DN measured by the measurement unit 50.
  • the processing unit dissolution unit 67 includes a purge pipe 68.
  • the purge pipe 68 discharges nitrogen gas into the processing container 11 to replace the gas inside the processing container 11 with nitrogen gas.
  • a flow rate adjusting valve 78 is arranged in the middle of the purge pipe 68.
  • the flow rate adjusting valve 78 adjusts the flow rate of the nitrogen gas discharged from the purge pipe 68 into the processing container 11 under the control of the control unit 90.
  • the control unit 90 determines the flow rate of the nitrogen gas discharged from the purge pipe 68 into the processing container 11 based on the dissolved nitrogen concentration DN measured by the measurement unit 50. As the flow rate of nitrogen gas increases, the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time increases, and the dissolved nitrogen concentration DN of the chemical liquid 3 increases. The dissolved nitrogen concentration DN never exceeds the saturated dissolved nitrogen concentration.
  • the dissolution unit for adjusting the dissolved nitrogen concentration DN of the chemical liquid 3 which of the storage unit dissolution unit 61, the recovery line dissolution units 64A and 64B, and the processing unit dissolution unit 67 is to be used is For example, it is determined based on whether the open/close valve 39 of the first branch line 33 is open or closed. When the open/close valve 39 is open, the chemical liquid 3 flows into the recovery line 41 from the processing container 11 of the processing unit 10. On the other hand, when the open/close valve 39 is closed, the chemical liquid 3 does not flow from the processing container 11 of the processing unit 10 into the recovery line 41.
  • the recovery line dissolution unit 64A on the upstream side discharges the nitrogen gas into the recovery line 41 to suppress a decrease in the dissolved nitrogen concentration DN of the chemical liquid 3.
  • the downstream recovery line dissolution unit 64B discharges the nitrogen gas into the recovery line 41 to restore the lowered dissolved nitrogen concentration DN to the original value.
  • the processing unit dissolution unit 67 may be used in place of the downstream recovery line dissolution unit 64B or together with the downstream recovery line dissolution unit 64B.
  • the processing unit dissolution unit 67 does not discharge the nitrogen gas into the processing container 11. Further, in this case, since the chemical liquid 3 does not flow inside the recovery line 41, the recovery line dissolution units 64A and 64B do not discharge the nitrogen gas into the recovery line 41. In this case, the storage unit dissolution unit 61 adjusts the dissolved nitrogen concentration DN.
  • FIG. 4 is a flowchart showing another part of the substrate processing method according to the embodiment. Steps S111 to S113 shown in FIG. 4 are repeated at predetermined time intervals. The steps S111 to S113 shown in FIG. 4 may be performed in parallel with the steps S101 to S106 shown in FIG. 3, or may be performed when the steps S101 to S106 shown in FIG. 3 are interrupted.
  • the substrate processing method has a step S111 of measuring the dissolved nitrogen concentration DN of the chemical liquid 3.
  • the measurement unit 50 measures the dissolved nitrogen concentration DN of the chemical liquid 3 and sends a signal indicating the measurement result to the control unit 90.
  • the substrate processing method has a step S112 of determining the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time based on the measured dissolved nitrogen concentration DN.
  • the control unit 90 determines the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time by the dissolution unit 60.
  • the control unit 90 determines the amount of nitrogen gas to be dissolved in the chemical liquid 3 per unit time by the dissolution unit by determining the flow rate of nitrogen gas at the location where the dissolution unit is installed for each dissolution unit that constitutes the dissolution unit 60. Decide This amount is also called "dissolved amount”.
  • the substrate processing method includes a step S113 of dissolving a predetermined amount of nitrogen gas in the chemical liquid 3.
  • the dissolving section 60 causes the chemical solution 3 to dissolve nitrogen gas under the control of the control section 90.
  • the controller 90 supplies the nitrogen gas at a flow rate determined for each melting unit to the place where each melting unit is installed.
  • the concentration DN of dissolved nitrogen that does not contribute to oxidation by controlling the concentration DN of dissolved nitrogen that does not contribute to oxidation, the total concentration of all dissolved gases that contribute to oxidation can be controlled, so that the etching rate ER can be accurately controlled.
  • FIG. 5 is a flowchart showing an example of the process of determining the dissolution amount. The steps S121 to S125 shown in FIG. 5 are performed by the control unit 90.
  • the control unit 90 determines whether or not the measured dissolved nitrogen concentration DN is equal to or higher than the set value DN1 (S121).
  • the set value DN1 is a lower limit value and is predetermined based on the etching rate ER.
  • the set value DN1 is determined so that the etching rate ER falls within a desired range. A detailed method of determining the set value DN1 will be described later.
  • the control unit 90 increases the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time by the dissolution unit 60 (S122). From the next time onward, the dissolved nitrogen concentration DN can be increased, and the dissolved nitrogen concentration DN can be controlled to be equal to or higher than the set value DN1. After that, the control unit 90 ends this processing.
  • the number of dissolution units that increase the dissolution amount in S122 may be one or more. Which dissolution unit to increase the dissolution amount of the plurality of dissolution units is determined, for example, based on whether the on-off valve 39 of the first branch line 33 is in the open state or the closed state, as described above. Note that which of the plurality of dissolution units is to be increased in dissolution amount may be determined based on the measurement results of the plurality of dissolved nitrogen concentration meters 51 installed at different locations.
  • the control unit 90 determines whether the measured dissolved nitrogen concentration DN is equal to or lower than the set value DN2 (S123).
  • the set value DN2 is an upper limit value and is the same value as the set value DN1 or a value larger than the set value DN1.
  • the set value DN2 is predetermined based on the etching rate ER.
  • the set value DN2 is determined so that the etching rate ER falls within a desired range. A detailed method of determining the set value DN2 will be described later.
  • the control unit 90 When the measured dissolved nitrogen concentration DN is larger than the set value DN2 (S123, NO), the control unit 90 reduces the amount of nitrogen gas dissolved in the chemical liquid 3 by the dissolving unit 60 per unit time (S124). From the next time onward, the dissolved nitrogen concentration DN can be reduced, and the dissolved nitrogen concentration DN can be controlled to be equal to or lower than the set value DN2. After that, the control unit 90 ends this processing.
  • the number of dissolution units that reduce the dissolution amount in S124 may be one or more.
  • which dissolving unit to reduce the dissolving amount is determined based on whether the on-off valve 39 of the first branch line 33 is in the open state or the closed state, as described above. It should be noted that which of the plurality of dissolution units is to be reduced in dissolution amount may be determined based on the measurement results of the plurality of dissolved nitrogen concentration meters 51 installed at different locations.
  • the control unit 90 maintains the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time by the dissolution unit 60 (S125). From the next time onward, the dissolved nitrogen concentration DN can be maintained at the same level. After that, the control unit 90 ends this processing.
  • the etching rate ER can be kept within a desired range.
  • the dissolved nitrogen concentration DN of the chemical liquid 3 is a control amount, and the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time is an operation amount.
  • FIG. 6 is a flowchart showing another part of the substrate processing method according to the embodiment. Steps S131 to S132 shown in FIG. 6 are repeated at predetermined time intervals. The steps S131 to S132 shown in FIG. 6 may be performed in parallel with the steps S101 to S106 shown in FIG. 3, or may be performed when the steps S101 to S106 shown in FIG. 3 are interrupted.
  • the substrate processing method has a step S131 of measuring the etching rate ER.
  • the etching rate measuring unit 80 (see FIG. 1) measures the etching rate ER.
  • the etching rate measurement unit 80 first measures the film thickness of the polysilicon film after etching, and calculates the film thickness difference of the polysilicon film before and after etching.
  • the etching rate measurement unit 80 calculates the etching rate ER by dividing the calculated film thickness difference by the etching time.
  • the etching rate measurement unit 80 transmits a signal indicating the measurement result to the control unit 90.
  • the substrate processing method has a step S132 of determining the set values DN1 and DN2 of the dissolved nitrogen concentration DN based on the measured etching rate ER. This step S132 is performed by the controller 90. Details of this step S132 will be described later.
  • FIG. 7 is a flowchart showing an example of a process of determining the set value of the dissolved nitrogen concentration. Steps S141 to S145 shown in FIG. 7 are performed by the control unit 90. The flowchart shown in FIG. 7 is for the case where the chemical liquid 3 is the TMAH-containing chemical liquid.
  • the concentration DN of dissolved nitrogen that does not contribute to oxidation the greater the total concentration of all dissolved gases that contribute to oxidation. Therefore, regardless of the type of the chemical liquid 3, the smaller the concentration DN of the dissolved nitrogen that does not contribute to the oxidation, the easier the oxidation of the polysilicon film.
  • the etching rate ER decreases as the oxidation of the polysilicon film progresses. This is because the TMAH-containing chemical solution is not good at etching the oxide film.
  • the chemical solution 3 is a TMAH-containing chemical solution
  • the concentration DN of dissolved nitrogen that does not contribute to oxidation the higher the total concentration of all dissolved gases that contribute to oxidation, and the smaller the etching rate ER.
  • the substrate processing method has a step S141 of determining whether or not the measured etching rate ER is equal to or higher than a threshold value ER1.
  • the threshold value ER1 is a lower limit value and is determined so that the number of processed substrates 2 per unit time is equal to or larger than the set number.
  • the control unit 90 increases the set values DN1 and DN2 of the dissolved nitrogen concentration DN (S142). From the next time onward, since the dissolved nitrogen concentration DN can be increased, the etching rate ER can be increased, and the etching rate ER can be controlled to be equal to or higher than the threshold value ER1. After that, the control unit 90 ends this processing.
  • the control unit 90 determines whether the measured etching rate ER is less than or equal to the threshold ER2 (S143).
  • the threshold value ER2 is an upper limit value and is the same value as the threshold value ER1 or a value larger than the threshold value ER1.
  • the threshold value ER2 is predetermined so that unintentional damage does not occur due to etching.
  • the controller 90 When the measured etching rate ER is larger than the threshold value ER2 (S143, NO), the controller 90 reduces the set values DN1 and DN2 of the dissolved nitrogen concentration DN (S144). From the next time onward, since the dissolved nitrogen concentration DN can be reduced, the etching rate ER can be reduced, and the etching rate ER can be controlled to be equal to or lower than the threshold value ER2. After that, the control unit 90 ends this processing.
  • the control unit 90 maintains the set values DN1 and DN2 of the dissolved nitrogen concentration DN (S145). From the next time onward, the etching rate ER can be maintained at the same level. After that, the control unit 90 ends this processing.
  • the etching rate ER is feedback-controlled, it is possible to keep the etching rate ER within a desired range.
  • the etching rate ER is the controlled variable, and the set values DN1 and DN2 of the dissolved nitrogen concentration DN are the manipulated variables.
  • the process of determining the set values DN1 and DN2 of the dissolved nitrogen concentration DN when the chemical liquid 3 is an ammonia solution or a choline solution will be described mainly with respect to the difference from FIG. 7.
  • the controller 90 decreases the set values DN1 and DN2 of the dissolved nitrogen concentration DN instead of increasing them (S142) (S144). ).
  • the control unit 90 increases the set values DN1 and DN2 of the dissolved nitrogen concentration DN instead of decreasing them (S144) (S142).
  • the etching rate ER can be kept within a desired range.
  • FIG. 9 is a diagram showing a modification of the storage unit dissolution unit shown in FIG. 1.
  • the storage unit dissolution unit 61 may include a purge pipe 62.
  • the purge pipe 62 discharges nitrogen gas into the upper space of the storage section 30.
  • the upper space of the reservoir 30 is a space above the liquid surface of the chemical liquid 3.
  • a flow rate adjusting valve 72 is arranged in the middle of the purge pipe 62. As the flow rate of nitrogen gas increases, the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time increases, and the dissolved nitrogen concentration DN of the chemical liquid 3 increases.
  • the storage unit dissolution unit 61 may include a drainage line 81.
  • the liquid drain line 81 discharges the chemical liquid 3 from the storage unit 30 when the height of the liquid surface of the chemical liquid 3 stored in the storage unit 30 reaches a set value, for example.
  • One end of the drainage line 81 is joined, for example, in the middle of the purge pipe 62.
  • One end of the purge pipe 62 opens at the ceiling of the storage unit 30, for example.
  • one end of the purge pipe 62 is open at the ceiling of the storage part 30 in FIG. 9, but may be projected downward from the ceiling of the storage part 30. In this case, if the height of the liquid surface of the chemical liquid 3 rises to one end of the purge pipe 62 before the storage portion 30 is filled with the chemical liquid 3, the chemical liquid 3 is discharged from the storage portion 30 to the drain line 81. Further, one end of the purge pipe 62 may be opened at the upper portion of the side wall of the storage section 30 or may be protruded inward from the upper side of the side wall of the storage section 30.
  • the drainage line 81 may be connected in the middle of the purge pipe 62 for nitrogen gas in FIG. 9, it may not be connected.
  • the drainage line 81 may be provided separately from the purge pipe 62.
  • a purge pipe for oxygen gas may be provided, and one end of the drainage line 81 may be joined in the middle of the purge pipe.
  • An opening/closing valve 82 is provided in the middle of the drainage line 81.
  • a liquid level sensor 83 is provided inside the storage unit 30. The liquid surface level sensor 83 detects whether or not the height of the liquid surface of the chemical liquid 3 has reached a set value.
  • the on-off valve 82 opens and closes the flow path of the drainage line 81 according to the detection result of the liquid level sensor 83.
  • the open/close valve 82 opens the flow path of the drain line 81. As a result, the chemical liquid 3 is discharged from the reservoir 30 to the drain line 81.
  • the open/close valve 82 closes the flow path of the drain line 81. It is possible to prevent the atmospheric pressure in the upper space of the storage unit 30 from becoming a negative pressure lower than the atmospheric pressure, and to prevent the chemical liquid 3 from volatilizing inside the storage unit 30.
  • the discharge destination of the chemical liquid 3 through the drain line 81 may be negative pressure. In this case, if the opening/closing valve 82 is not provided, the atmospheric pressure in the upper space of the storage section 30 is likely to be negative.
  • the storage unit dissolution unit 61 may include an exhaust line 84.
  • the exhaust line 84 releases the gas accumulated in the upper space of the storage unit 30 to the outside in order to suppress the atmospheric pressure of the upper space of the storage unit 30 from becoming a positive pressure higher than the atmospheric pressure.
  • One end of the exhaust line 84 is joined, for example, in the middle of the purge pipe 62.
  • the exhaust line 84 is connected to the purge pipe 62 at a point farther from the storage section 30 than the drainage line 81 so that the chemical liquid 3 does not flow into the exhaust line 84.

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Abstract

This substrate processing device is provided with: a processing unit for etching a polysilicon film or an amorphous silicon film formed on a substrate by using an alkaline chemical liquid in which nitrogen gas has been dissolved; a measurement unit that measures a dissolved nitrogen concentration in the chemical liquid; a dissolving unit that dissolves the nitrogen gas in the chemical liquid; and a control unit that determines the amount of nitrogen gas to be dissolved, per unit time, in the chemical liquid by the dissolving unit on the basis of the dissolved nitrogen concentration measured by the measurement unit.

Description

基板処理装置、および基板処理方法Substrate processing apparatus and substrate processing method
　本開示は、基板処理装置、および基板処理方法に関する。 The present disclosure relates to a substrate processing apparatus and a substrate processing method.
　特許文献１に記載の基板処理方法は、酸素ガスを溶解させたＴＭＡＨ（水酸化テトラメチルアンモニウム）含有薬液を薬液ノズルから吐出することにより、基板に形成されたポリシリコン膜をエッチングする。この基板処理方法は、ＴＭＡＨ含有薬液の溶存酸素濃度を測定する。この基板処理方法は、測定した溶存酸素濃度が予め定めた濃度よりも高い場合、ＴＭＡＨ含有薬液に窒素ガスを溶解させて、エッチングレートを下げる。また、この基板処理方法は、測定した溶存酸素濃度が予め定めた濃度よりも低い場合、ＴＭＡＨ含有薬液に酸素ガスを溶解させて、エッチングレートを上げる。 The substrate processing method described in Patent Document 1 etches the polysilicon film formed on the substrate by discharging a TMAH (tetramethylammonium hydroxide)-containing chemical solution in which oxygen gas is dissolved from a chemical solution nozzle. This substrate processing method measures the dissolved oxygen concentration of a TMAH-containing chemical solution. In this substrate processing method, when the measured dissolved oxygen concentration is higher than a predetermined concentration, nitrogen gas is dissolved in the TMAH-containing chemical solution to reduce the etching rate. Further, in this substrate processing method, when the measured dissolved oxygen concentration is lower than a predetermined concentration, oxygen gas is dissolved in the TMAH-containing chemical solution to increase the etching rate.
日本国特開２０１３－２５８３９１号公報Japanese Patent Laid-Open No. 2013-258391
　本開示の一態様は、アルカリ性の薬液による、ポリシリコン膜またはアモルファスシリコン膜のエッチングレートを精度良く管理できる、技術を提供する。 One aspect of the present disclosure provides a technique capable of accurately controlling the etching rate of a polysilicon film or an amorphous silicon film with an alkaline chemical solution.
　本開示の一態様に係る基板処理装置は、
　基板に形成されたポリシリコン膜またはアモルファスシリコン膜を、窒素ガスを予め溶解させたアルカリ性の薬液でエッチングする処理部と、
　前記薬液の溶存窒素濃度を測定する測定部と、
　前記薬液に窒素ガスを溶解させる溶解部と、
　前記測定部によって測定した溶存窒素濃度を基に、前記溶解部によって単位時間当たりに前記薬液に溶解させる窒素ガスの量を決める制御部とを備える。 A substrate processing apparatus according to one aspect of the present disclosure,
A processing unit for etching the polysilicon film or the amorphous silicon film formed on the substrate with an alkaline chemical solution in which nitrogen gas is previously dissolved,
A measuring unit for measuring the dissolved nitrogen concentration of the chemical solution,
A dissolving portion for dissolving nitrogen gas in the chemical solution,
And a control unit that determines the amount of nitrogen gas to be dissolved in the chemical liquid per unit time by the dissolution unit based on the dissolved nitrogen concentration measured by the measurement unit.
　本開示の一態様によれば、アルカリ性の薬液による、ポリシリコン膜またはアモルファスシリコン膜のエッチングレートを精度良く管理できる。 According to one aspect of the present disclosure, it is possible to accurately control the etching rate of a polysilicon film or an amorphous silicon film with an alkaline chemical solution.
図１は、一実施形態に係る基板処理装置を示す図である。FIG. 1 is a diagram showing a substrate processing apparatus according to an embodiment. 図２は、一実施形態に係る処理部を示す図である。FIG. 2 is a diagram illustrating a processing unit according to an embodiment. 図３は、一実施形態に係る基板処理方法の一部を示すフローチャートである。FIG. 3 is a flowchart showing a part of the substrate processing method according to the embodiment. 図４は、一実施形態に係る基板処理方法の別の一部を示すフローチャートである。FIG. 4 is a flowchart showing another part of the substrate processing method according to the embodiment. 図５は、溶解量を決定する工程の一例を示すフローチャートである。FIG. 5 is a flowchart showing an example of the process of determining the dissolution amount. 図６は、一実施形態に係る基板処理方法のさらに別の一部を示すフローチャートである。FIG. 6 is a flowchart showing yet another part of the substrate processing method according to the embodiment. 図７は、溶存窒素濃度の設定値を決める工程の一例を示すフローチャートである。FIG. 7 is a flowchart showing an example of a step of determining the set value of the dissolved nitrogen concentration. 図８は、図１に示す上流側の回収ライン用溶解ユニットの一例を示す図である。FIG. 8 is a diagram showing an example of the upstream recovery line dissolving unit shown in FIG. 1. 図９は、図１に示す貯留部用溶解ユニットの変形例を示す図である。9: is a figure which shows the modification of the dissolving|melting unit for storage parts shown in FIG.
　以下、本開示の実施形態について図面を参照して説明する。尚、各図面において同一の又は対応する構成には同一の又は対応する符号を付し、説明を省略することがある。本明細書において、下方とは鉛直方向下方を意味し、上方とは鉛直方向上方を意味する。 Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding components are designated by the same or corresponding reference numerals, and description thereof may be omitted. In the present specification, the lower side means the lower side in the vertical direction, and the upper side means the upper side in the vertical direction.
　図１は、一実施形態に係る基板処理装置を示す図である。基板処理装置１は、例えば、処理部１０を備える。処理部１０は、基板２（図２参照）に形成されたポリシリコン膜を、窒素ガスを予め溶解させたアルカリ性の薬液３でエッチングする。 FIG. 1 is a diagram showing a substrate processing apparatus according to an embodiment. The substrate processing apparatus 1 includes a processing unit 10, for example. The processing unit 10 etches the polysilicon film formed on the substrate 2 (see FIG. 2) with the alkaline chemical liquid 3 in which nitrogen gas is dissolved in advance.
　薬液３は、ポリシリコン膜の代わりに形成される、アモルファスシリコン膜をエッチングしてもよい。アモルファスシリコン膜も、ポリシリコン膜と同様にエッチングされる。ポリシリコン膜もアモルファスシリコン膜も、薬液３中の溶存ガスによって酸化されることがある。溶存ガスによる酸化については、後述する。 The chemical solution 3 may etch an amorphous silicon film formed instead of the polysilicon film. The amorphous silicon film is also etched similarly to the polysilicon film. Both the polysilicon film and the amorphous silicon film may be oxidized by the dissolved gas in the chemical liquid 3. The oxidation with the dissolved gas will be described later.
　図２は、一実施形態に係る処理部を示す図である。処理部１０は、例えば、処理容器１１と、基板保持部１３と、回転駆動機構１６と、ノズル２０と、カップ２５とを有する。処理部１０は、本実施形態では基板２を一枚ずつ処理する枚葉式であるが、基板２を複数枚ずつ同時に処理するバッチ式でもよい。処理部１０は、枚葉式であってもバッチ式であっても、処理容器１１を有する。 FIG. 2 is a diagram showing a processing unit according to one embodiment. The processing unit 10 includes, for example, a processing container 11, a substrate holding unit 13, a rotation driving mechanism 16, a nozzle 20, and a cup 25. In the present embodiment, the processing unit 10 is a single-wafer type that processes the substrates 2 one by one, but may be a batch type that simultaneously processes a plurality of substrates 2. The processing unit 10 has a processing container 11 whether it is a single-wafer type or a batch type.
　処理容器１１は、基板２を内部に収容する。処理容器１１は、基板２が処理容器１１の外部から処理容器１１の内部に搬入されるゲートと、ゲートを開閉するゲートバルブとを有する。処理容器１１の内部で処理された基板２は、ゲートを通り処理容器１１の外部に搬出される。 The processing container 11 accommodates the substrate 2 inside. The processing container 11 has a gate for loading the substrate 2 into the processing container 11 from the outside of the processing container 11, and a gate valve for opening and closing the gate. The substrate 2 processed inside the processing container 11 is carried out of the processing container 11 through the gate.
　基板保持部１３は、処理容器１１の内部に搬入された基板２を水平に保持する。基板保持部１３は、基板２のポリシリコン膜が形成された面を上に向けて、基板２を水平に保持する。基板保持部１３は、図２ではメカニカルチャックであるが、真空チャックまたは静電チャックなどであってもよい。基板保持部１３は、鉛直に配置される回転軸部１４を有する。回転軸部１４は、軸受１５によって回転自在に支持される。 The substrate holding unit 13 horizontally holds the substrate 2 loaded in the processing container 11. The substrate holding unit 13 holds the substrate 2 horizontally with the surface of the substrate 2 on which the polysilicon film is formed facing upward. Although the substrate holding unit 13 is a mechanical chuck in FIG. 2, it may be a vacuum chuck or an electrostatic chuck. The substrate holding part 13 has a rotating shaft part 14 arranged vertically. The rotating shaft portion 14 is rotatably supported by a bearing 15.
　回転駆動機構１６は、基板保持部１３を回転させる。回転駆動機構１６は、回転モータ１７と、回転モータ１７の回転運動を回転軸部１４に伝達する伝達機構１８とを有する。伝達機構１８は、例えばプーリとタイミングベルトとで構成される。なお、伝達機構１８は、ギヤなどで構成されてもよい。 The rotation drive mechanism 16 rotates the substrate holding unit 13. The rotary drive mechanism 16 includes a rotary motor 17 and a transmission mechanism 18 that transmits the rotary motion of the rotary motor 17 to the rotary shaft portion 14. The transmission mechanism 18 includes, for example, a pulley and a timing belt. The transmission mechanism 18 may be composed of a gear or the like.
　ノズル２０は、基板保持部１３に保持されている基板２に対し、窒素ガスを予め溶解させたアルカリ性の薬液３を供給する。ノズル２０は、薬液３を吐出する吐出口２１を有する。ノズル２０は、吐出口２１を下に向けて基板２の上方に配置される。ノズル２０は、基板２の上方において、基板２の径方向に移動可能である。 The nozzle 20 supplies the alkaline chemical liquid 3 in which nitrogen gas is dissolved in advance to the substrate 2 held by the substrate holding portion 13. The nozzle 20 has a discharge port 21 for discharging the chemical liquid 3. The nozzle 20 is arranged above the substrate 2 with the ejection port 21 facing downward. The nozzle 20 is movable in the radial direction of the substrate 2 above the substrate 2.
　ノズル２０は、例えば、基板保持部１３と共に回転している基板２の中心部に、薬液３を供給する。回転している基板２の中心部に供給された薬液３は、遠心力によって基板２の上面全体に濡れ広がり、液膜を形成する。液膜は、ポリシリコン膜をエッチングする。 The nozzle 20 supplies the chemical liquid 3 to the central portion of the substrate 2 rotating together with the substrate holding unit 13, for example. The chemical liquid 3 supplied to the central portion of the rotating substrate 2 wets and spreads over the entire upper surface of the substrate 2 due to a centrifugal force to form a liquid film. The liquid film etches the polysilicon film.
　薬液３は、例えばＴＭＡＨ（水酸化テトラメチルアンモニウム）を含むＴＭＡＨ含有薬液である。薬液３は、本実施形態ではＴＭＡＨ含有薬液であるが、ポリシリコン膜をエッチングするものであればよい。例えば、薬液３はアンモニア溶液またはコリン溶液などであってもよい。 The chemical liquid 3 is a TMAH-containing chemical liquid containing TMAH (tetramethylammonium hydroxide), for example. Although the chemical liquid 3 is the TMAH-containing chemical liquid in this embodiment, it may be any liquid as long as it etches the polysilicon film. For example, the drug solution 3 may be an ammonia solution or a choline solution.
　なお、ノズル２０は、エッチング用の薬液３の他、リンス液、および乾燥液を吐出してもよい。薬液３、リンス液、および乾燥液など、基板２を処理する液を「処理液」とも呼ぶ。一のノズル２０が複数種類の処理液を順番に吐出してもよいし、複数のノズル２０が異なる処理液を吐出してもよい。 Note that the nozzle 20 may discharge a rinse liquid and a drying liquid in addition to the chemical liquid 3 for etching. The liquid that processes the substrate 2, such as the chemical liquid 3, the rinse liquid, and the drying liquid, is also referred to as a “processing liquid”. One nozzle 20 may eject a plurality of types of treatment liquids in order, or a plurality of nozzles 20 may eject different treatment liquids.
　リンス液としては、特に限定されないが、例えばＤＩＷ（脱イオン水）が用いられる。リンス液は、薬液３に続いて用いられる。リンス液は、薬液３を置換しながら、遠心力によって基板２の中心部から基板２の外周部に濡れ広がり、液膜を形成する。リンス液としては、特に限定されないが、例えばＤＩＷ（脱イオン水）などの水が用いられる。 The rinse liquid is not particularly limited, but DIW (deionized water) is used, for example. The rinse liquid is used after the chemical liquid 3. The rinsing liquid wets and spreads from the central portion of the substrate 2 to the outer peripheral portion of the substrate 2 by the centrifugal force while replacing the chemical liquid 3 to form a liquid film. The rinse liquid is not particularly limited, but water such as DIW (deionized water) is used, for example.
　乾燥液としては、リンス液より揮発性が高ければ特に限定されないが、例えばＩＰＡ（イソプロピルアルコール）が用いられる。乾燥液は、リンス液を置換しながら、遠心力によって基板２の中心部から基板２の外周部に濡れ広がり、液膜を形成する。乾燥液としては、特に限定されないが、例えばＩＰＡ（イソプロピルアルコール）などの有機溶媒が用いられる。 The drying liquid is not particularly limited as long as it is more volatile than the rinse liquid, but IPA (isopropyl alcohol) is used, for example. While substituting the rinse liquid, the drying liquid wets and spreads from the central portion of the substrate 2 to the outer peripheral portion of the substrate 2 by a centrifugal force, forming a liquid film. The drying liquid is not particularly limited, but an organic solvent such as IPA (isopropyl alcohol) is used.
　なお、ノズル２０は、エッチング用の薬液３とは別の薬液を吐出してもよく、例えばエッチング用の薬液３の前に洗浄用の薬液を吐出してもよい。エッチング前のポリシリコン膜の汚染物を洗浄用の薬液によって除去できる。洗浄用の薬液としては、例えばＤＨＦ（希フッ酸）、ＳＣ－１（水酸化アンモニウムと過酸化水素とを含む水溶液）、またはＳＣ－２（塩化水素と過酸化水素とを含む水溶液）などが挙げられる。 The nozzle 20 may eject a chemical liquid different from the chemical liquid 3 for etching, for example, a chemical liquid for cleaning may be ejected before the chemical liquid 3 for etching. The contaminants on the polysilicon film before etching can be removed with a cleaning chemical. Examples of the cleaning chemicals include DHF (dilute hydrofluoric acid), SC-1 (aqueous solution containing ammonium hydroxide and hydrogen peroxide), or SC-2 (aqueous solution containing hydrogen chloride and hydrogen peroxide). Can be mentioned.
　カップ２５は、基板保持部１３を取り囲むように配置され、基板保持部１３と共に回転している基板２から飛散する薬液３などの処理液を捕集する。カップ２５の底部には、排液管２６と排気管２７とが設けられる。排液管２６はカップ２５内の処理液を排出し、排気管２７はカップ２５内のガスを排出する。 The cup 25 is arranged so as to surround the substrate holding unit 13, and collects the processing liquid such as the chemical liquid 3 scattered from the substrate 2 rotating with the substrate holding unit 13. A drain pipe 26 and an exhaust pipe 27 are provided at the bottom of the cup 25. The drain pipe 26 discharges the processing liquid in the cup 25, and the exhaust pipe 27 discharges the gas in the cup 25.
　カップ２５は、基板保持部１３を回転自在に支持する軸受１５を保持しており、基板保持部１３と共に回転しない。なお、カップ２５は、本実施形態では基板保持部１３と共に回転しないが、基板保持部１３と共に回転してもよい。 The cup 25 holds the bearing 15 that rotatably supports the substrate holding unit 13, and does not rotate together with the substrate holding unit 13. Although the cup 25 does not rotate with the substrate holding unit 13 in this embodiment, it may rotate with the substrate holding unit 13.
　基板処理装置１は、図１に示すように、制御部９０を備える。制御部９０は、例えばコンピュータで構成され、ＣＰＵ（Central Processing Unit）９１と、メモリなどの記憶媒体９２とを備える。記憶媒体９２には、基板処理装置１において実行される各種の処理を制御するプログラムが格納される。制御部９０は、記憶媒体９２に記憶されたプログラムをＣＰＵ９１に実行させることにより、基板処理装置１の動作を制御する。また、制御部９０は、入力インターフェース９３と、出力インターフェース９４とを備える。制御部９０は、入力インターフェース９３で外部からの信号を受信し、出力インターフェース９４で外部に信号を送信する。 The substrate processing apparatus 1 includes a control unit 90 as shown in FIG. The control unit 90 is configured by, for example, a computer, and includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as a memory. The storage medium 92 stores programs that control various processes executed in the substrate processing apparatus 1. The control unit 90 controls the operation of the substrate processing apparatus 1 by causing the CPU 91 to execute the program stored in the storage medium 92. The controller 90 also includes an input interface 93 and an output interface 94. In the control unit 90, the input interface 93 receives a signal from the outside, and the output interface 94 transmits the signal to the outside.
　かかるプログラムは、コンピュータによって読み取り可能な記憶媒体に記憶されていたものであって、その記憶媒体から制御部９０の記憶媒体９２にインストールされたものであってもよい。コンピュータによって読み取り可能な記憶媒体としては、例えば、ハードディスク（ＨＤ）、フレキシブルディスク（ＦＤ）、コンパクトディスク（ＣＤ）、マグネットオプティカルデスク（ＭＯ）、メモリーカードなどが挙げられる。なお、プログラムは、インターネットを介してサーバからダウンロードされ、制御部９０の記憶媒体９２にインストールされてもよい。 The program may be stored in a computer-readable storage medium, and may be installed in the storage medium 92 of the control unit 90 from the storage medium. Examples of the computer-readable storage medium include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical desk (MO), and a memory card. The program may be downloaded from the server via the Internet and installed in the storage medium 92 of the control unit 90.
　図３は、一実施形態に係る基板処理方法の一部を示すフローチャートである。図３に示す工程Ｓ１０１～Ｓ１０６は、制御部９０による制御下で実施され、基板２を替えて繰り返し行われる。 FIG. 3 is a flowchart showing a part of the substrate processing method according to the embodiment. Steps S101 to S106 shown in FIG. 3 are performed under the control of the controller 90, and are repeatedly performed by changing the substrate 2.
　基板処理方法は、基板２を処理容器１１の内部に搬入する工程Ｓ１０１を有する。この工程Ｓ１０１では、搬送装置が、処理容器１１の外部から処理容器１１の内部に基板２を搬入し、搬入した基板２を基板保持部１３に受け渡す。基板保持部１３は、基板２のポリシリコン膜が形成された面を上に向けて、基板２を水平に保持する。 The substrate processing method has a step S101 of loading the substrate 2 into the processing container 11. In this step S101, the transfer device carries the substrate 2 into the processing container 11 from the outside of the processing container 11, and transfers the carried-in substrate 2 to the substrate holding unit 13. The substrate holding unit 13 holds the substrate 2 horizontally with the surface of the substrate 2 on which the polysilicon film is formed facing upward.
　基板処理方法は、基板２の上面に薬液３を供給する工程Ｓ１０２を有する。この工程Ｓ１０２では、ノズル２０が基板保持部１３と共に回転している基板２の中心部に、上方から薬液３を供給する。供給された薬液３は、遠心力によって基板２の上面全体に濡れ広がり、液膜を形成する。液膜は、基板２に形成されたポリシリコン膜をエッチングする。 The substrate processing method includes a step S102 of supplying the chemical liquid 3 to the upper surface of the substrate 2. In this step S102, the chemical liquid 3 is supplied from above to the central portion of the substrate 2 in which the nozzle 20 is rotating together with the substrate holding portion 13. The supplied chemical liquid 3 wets and spreads over the entire upper surface of the substrate 2 due to a centrifugal force to form a liquid film. The liquid film etches the polysilicon film formed on the substrate 2.
　基板処理方法は、基板２の上面にリンス液を供給する工程Ｓ１０３を有する。この工程Ｓ１０３では、ノズル２０が基板保持部１３と共に回転している基板２の中心部に、上方からリンス液を供給する。供給されたリンス液は、薬液３を置換しながら、遠心力によって基板２の上面全体に濡れ広がり、液膜を形成する。薬液３は、リンス液に置換され、除去される。 The substrate processing method has a step S103 of supplying a rinse liquid to the upper surface of the substrate 2. In this step S103, the rinse liquid is supplied from above to the central portion of the substrate 2 in which the nozzle 20 is rotating together with the substrate holding portion 13. The supplied rinsing liquid replaces the chemical liquid 3 and wets and spreads over the entire upper surface of the substrate 2 by a centrifugal force to form a liquid film. The chemical liquid 3 is replaced with the rinse liquid and removed.
　基板処理方法は、基板２の上面に乾燥液を供給する工程Ｓ１０４を有する。この工程Ｓ１０４では、ノズル２０が基板保持部１３と共に回転している基板２の中心部に、上方から乾燥液を供給する。供給された乾燥液は、リンス液を置換しながら、遠心力によって基板２の上面全体に濡れ広がり、液膜を形成する。リンス液は、乾燥液に置換され、除去される。 The substrate processing method has a step S104 of supplying a drying liquid onto the upper surface of the substrate 2. In this step S104, the drying liquid is supplied from above to the central portion of the substrate 2 in which the nozzle 20 is rotating together with the substrate holding portion 13. The supplied drying liquid replaces the rinsing liquid and spreads over the entire upper surface of the substrate 2 by centrifugal force to form a liquid film. The rinse liquid is replaced with a dry liquid and removed.
　基板処理方法は、基板２を乾燥する工程Ｓ１０５を有する。この工程では、ノズル２０が乾燥液の吐出を停止すると共に、回転駆動機構１６が基板保持部１３と共に基板２を回転する。基板２に残る乾燥液は、遠心力によって基板２から振り切られる。これにより、基板２の乾燥が行われる。 The substrate processing method includes a step S105 of drying the substrate 2. In this step, the nozzle 20 stops the discharge of the drying liquid, and the rotation drive mechanism 16 rotates the substrate 2 together with the substrate holding unit 13. The drying liquid remaining on the substrate 2 is shaken off from the substrate 2 by the centrifugal force. Thereby, the substrate 2 is dried.
　基板処理方法は、基板２を処理容器１１の内部から処理容器１１の外部に搬出する工程Ｓ１０６を有する。この工程Ｓ１０６では、先ず、基板保持部１３が基板２の保持を解除する。次に、搬送装置が基板保持部１３から基板２を受け取り、受け取った基板２を処理容器１１の内部から処理容器１１の外部に搬出する。 The substrate processing method has a step S106 of unloading the substrate 2 from the inside of the processing container 11 to the outside of the processing container 11. In step S106, the substrate holding unit 13 first releases the holding of the substrate 2. Next, the transfer device receives the substrate 2 from the substrate holder 13 and carries the received substrate 2 out of the processing container 11 to the outside of the processing container 11.
　なお、図３に示す工程の一部は実施されなくてもよい。例えば、乾燥液を供給する工程Ｓ１０４は実施されなくてもよい。この場合、基板２を乾燥する工程Ｓ１０５では、ノズル２０がリンス液の吐出を停止すると共に、回転駆動機構１６が基板保持部１３と共に基板２を回転する。基板２に残るリンス液は、遠心力によって基板２から振り切られる。これにより、基板２の乾燥が行われる。 Note that some of the steps shown in FIG. 3 may not be performed. For example, step S104 of supplying the drying liquid may not be performed. In this case, in step S105 of drying the substrate 2, the nozzle 20 stops discharging the rinse liquid, and the rotation drive mechanism 16 rotates the substrate 2 together with the substrate holding unit 13. The rinse liquid remaining on the substrate 2 is shaken off from the substrate 2 by the centrifugal force. Thereby, the substrate 2 is dried.
　次に、図１を再度参照して、薬液３の流体回路について説明する。基板処理装置１は、薬液３を貯留する貯留部３０と、貯留部３０から処理部１０に薬液３を供給する供給ライン３１とを備える。貯留部３０は、例えば、薬液３を貯留するタンクである。供給ライン３１は、例えば、循環ライン３２と、第１分岐ライン３３と、第２分岐ライン３４とを有する。 Next, referring again to FIG. 1, the fluid circuit of the chemical liquid 3 will be described. The substrate processing apparatus 1 includes a storage unit 30 that stores the chemical liquid 3, and a supply line 31 that supplies the chemical liquid 3 from the storage unit 30 to the processing unit 10. The storage unit 30 is, for example, a tank that stores the chemical liquid 3. The supply line 31 has, for example, a circulation line 32, a first branch line 33, and a second branch line 34.
　循環ライン３２は、貯留部３０から取り出した薬液３を貯留部３０に戻す。循環ライン３２の上流端３２ａは貯留部３０に結合し、循環ライン３２の下流端３２ｂも貯留部３０に結合する。循環ライン３２の途中には、薬液３を送り出すポンプ３５と、薬液３中の異物を捕集するフィルター３６と、薬液３を加熱するヒータ３７とが配置される。ヒータ３７は、制御部９０による制御下で、不図示の温度計の計測温度が設定温度になるように薬液３を加熱する。処理部１０に供給される薬液３の温度を設定温度に維持できる。なお、ポンプ３５と、フィルター３６と、ヒータ３７との順番は、図１に示す順番には限定されない。 The circulation line 32 returns the drug solution 3 taken out from the storage section 30 to the storage section 30. The upstream end 32a of the circulation line 32 is connected to the storage part 30, and the downstream end 32b of the circulation line 32 is also connected to the storage part 30. A pump 35 that sends out the chemical liquid 3, a filter 36 that collects foreign substances in the chemical liquid 3, and a heater 37 that heats the chemical liquid 3 are arranged in the circulation line 32. Under the control of the controller 90, the heater 37 heats the chemical liquid 3 so that the temperature measured by a thermometer (not shown) reaches the set temperature. The temperature of the chemical liquid 3 supplied to the processing unit 10 can be maintained at the set temperature. The order of the pump 35, the filter 36, and the heater 37 is not limited to the order shown in FIG.
　第１分岐ライン３３は、循環ライン３２の第１分岐点３８から分岐し、処理部１０まで延びる。第１分岐ライン３３の上流端は循環ライン３２の第１分岐点３８に結合し、第１分岐ライン３３の下流端は処理部１０に結合する。貯留部３０から取り出された薬液３は、循環ライン３２の上流端３２ａから循環ライン３２の第１分岐点３８まで流れ、その後、第１分岐ライン３３を通り、処理部１０に供給される。第１分岐ライン３３は、処理部１０毎に設けられる。第１分岐ライン３３の途中には、第１分岐ライン３３の流路を開閉する開閉弁３９が設けられる。開閉弁３９の開閉は、制御部９０によって制御される。 The first branch line 33 branches from the first branch point 38 of the circulation line 32 and extends to the processing unit 10. The upstream end of the first branch line 33 is connected to the first branch point 38 of the circulation line 32, and the downstream end of the first branch line 33 is connected to the processing unit 10. The chemical liquid 3 taken out from the storage unit 30 flows from the upstream end 32 a of the circulation line 32 to the first branch point 38 of the circulation line 32, and then passes through the first branch line 33 and is supplied to the processing unit 10. The first branch line 33 is provided for each processing unit 10. An opening/closing valve 39 that opens and closes the flow path of the first branch line 33 is provided in the middle of the first branch line 33. The opening and closing of the on-off valve 39 is controlled by the control unit 90.
　第２分岐ライン３４は、循環ライン３２の第２分岐点４０から分岐し、貯留部３０まで延びる。第２分岐点４０は、全ての第１分岐点３８よりも、循環ライン３２の上流端３２ａ側に配置される。第２分岐ライン３４の上流端は循環ライン３２の第２分岐点４０に結合し、第２分岐ライン３４の下流端は貯留部３０に結合する。貯留部３０から取り出された薬液３は、循環ライン３２の上流端３２ａから循環ライン３２の第２分岐点４０まで流れ、その後、第２分岐ライン３４を通り、貯留部３０まで戻される。第２分岐ライン３４の途中には、後述の溶存窒素濃度計５１が配置される。 The second branch line 34 branches from the second branch point 40 of the circulation line 32 and extends to the storage section 30. The second branch point 40 is arranged closer to the upstream end 32a of the circulation line 32 than all the first branch points 38. The upstream end of the second branch line 34 is connected to the second branch point 40 of the circulation line 32, and the downstream end of the second branch line 34 is connected to the storage section 30. The chemical liquid 3 taken out from the storage section 30 flows from the upstream end 32 a of the circulation line 32 to the second branch point 40 of the circulation line 32, and then passes through the second branch line 34 and is returned to the storage section 30. A dissolved nitrogen concentration meter 51 described later is arranged in the middle of the second branch line 34.
　基板処理装置１は、処理部１０から貯留部３０に薬液３を戻す回収ライン４１を備える。回収ライン４１は、主ライン４２と、副ライン４３とを有する。主ライン４２は、一の処理部１０から貯留部３０まで延びる。副ライン４３は、他の一の処理部１０から主ライン４２の途中まで延びる。副ライン４３の数は、図１では１つであるが、複数でもよい。副ライン４３の数は、処理部１０の数よりも１つ少なければよい。処理部１０の処理容器１１の内部で、ノズル２０から吐出された薬液３は、回収ライン４１を通り、貯留部３０に戻される。薬液３の廃棄量を減らすことができる。なお、ノズル２０から吐出された薬液３の一部は、貯留部３０に戻されることなく、廃棄されてもよい。 The substrate processing apparatus 1 includes a recovery line 41 that returns the chemical liquid 3 from the processing unit 10 to the storage unit 30. The recovery line 41 has a main line 42 and a sub line 43. The main line 42 extends from the one processing unit 10 to the storage unit 30. The sub line 43 extends from the other one processing unit 10 to the middle of the main line 42. Although the number of the sub-lines 43 is one in FIG. 1, it may be plural. The number of sub-lines 43 may be one less than the number of processing units 10. Inside the processing container 11 of the processing unit 10, the chemical liquid 3 discharged from the nozzle 20 passes through the recovery line 41 and is returned to the storage unit 30. The amount of the chemical solution 3 to be discarded can be reduced. It should be noted that part of the chemical liquid 3 discharged from the nozzle 20 may be discarded without being returned to the storage section 30.
　ところで、薬液３によるポリシリコン膜のエッチングレートＥＲは、薬液３の溶存酸素濃度などで決まる。溶存酸素とは、液体中に溶解している分子状の酸素（Ｏ２）のことである。溶存酸素濃度（単位：ｍｇ／Ｌ）が大きいほど、ポリシリコン膜が酸化されやすく、酸化膜が形成されやすい。 By the way, the etching rate ER of the polysilicon film by the chemical liquid 3 is determined by the dissolved oxygen concentration of the chemical liquid 3 and the like. Dissolved oxygen is molecular oxygen (O 2 ) dissolved in a liquid. The larger the dissolved oxygen concentration (unit: mg/L), the more easily the polysilicon film is oxidized and the more easily the oxide film is formed.
　薬液３がＴＭＡＨ含有薬液である場合、ポリシリコン膜の酸化が進むほど、ポリシリコン膜のエッチングレートＥＲが小さくなる。ＴＭＡＨ含有薬液は、酸化膜のエッチングが不得手だからである。 When the chemical liquid 3 is a TMAH-containing chemical liquid, the etching rate ER of the polysilicon film decreases as the oxidation of the polysilicon film progresses. This is because the TMAH-containing chemical solution is not good at etching the oxide film.
　従って、薬液３がＴＭＡＨ含有薬液である場合、薬液３の溶存酸素濃度が大きいほど、薬液３によるポリシリコン膜のエッチングレートＥＲが小さくなる。この傾向は、特許文献１に記載された傾向とは逆の傾向である。 Therefore, when the chemical liquid 3 is a TMAH-containing chemical liquid, the higher the dissolved oxygen concentration of the chemical liquid 3, the smaller the etching rate ER of the polysilicon film by the chemical liquid 3. This tendency is opposite to the tendency described in Patent Document 1.
　なお、薬液３がアンモニア溶液またはコリン溶液である場合、ポリシリコン膜の酸化が進むほど、ポリシリコン膜のエッチングレートＥＲが大きくなる。アンモニア溶液及びコリン溶液は、酸化膜のエッチングが得意だからである。 When the chemical solution 3 is an ammonia solution or a choline solution, the etching rate ER of the polysilicon film increases as the oxidation of the polysilicon film progresses. This is because the ammonia solution and the choline solution are good at etching the oxide film.
　従って、薬液３がアンモニア溶液またはコリン溶液である場合、薬液３の溶存酸素濃度が大きいほど、薬液３によるポリシリコン膜のエッチングレートＥＲが大きくなる。 Therefore, when the chemical solution 3 is an ammonia solution or a choline solution, the higher the dissolved oxygen concentration of the chemical solution 3, the greater the etching rate ER of the polysilicon film by the chemical solution 3.
　上記特許文献１では、薬液３の溶存酸素濃度を測定する。酸素（Ｏ２）は、ポリシリコン膜を酸化させる溶存ガスの１つであって、全てではない。例えばオゾン（Ｏ３）なども、ポリシリコン膜を酸化させる溶存ガスである。上記特許文献１では、酸化に寄与する溶存ガスの合計の濃度を測定しないので、薬液３によるポリシリコン膜のエッチングレートＥＲの精度が低くなってしまう。 In the said patent document 1, the dissolved oxygen concentration of the chemical|medical solution 3 is measured. Oxygen (O 2 ) is one of the dissolved gases that oxidize the polysilicon film, but not all. For example, ozone (O 3 ) is also a dissolved gas that oxidizes the polysilicon film. In Patent Document 1 described above, since the total concentration of the dissolved gas that contributes to oxidation is not measured, the accuracy of the etching rate ER of the polysilicon film by the chemical liquid 3 becomes low.
　これに対し、本実施形態の基板処理装置１は、薬液３の溶存窒素濃度ＤＮ（単位：ｍｇ／Ｌ）を測定する。ヘンリーの法則（Henry’s Law）によれば、飽和溶存窒素濃度から、測定した溶存窒素濃度ＤＮを引いた差ΔＤＮは、窒素以外の全ての溶存ガスの分圧を表す。窒素以外の全ての溶存ガスには、酸化に寄与する全ての溶存ガスが含まれる。 On the other hand, the substrate processing apparatus 1 of the present embodiment measures the dissolved nitrogen concentration DN (unit: mg/L) of the chemical liquid 3. According to Henry's Law, the difference ΔDN obtained by subtracting the measured dissolved nitrogen concentration DN from the saturated dissolved nitrogen concentration represents the partial pressure of all dissolved gases other than nitrogen. All dissolved gases other than nitrogen include all dissolved gases that contribute to oxidation.
　飽和溶存窒素濃度は一定であるので、測定した溶存窒素濃度ＤＮが小さいほど、差ΔＤＮが大きい。差ΔＤＮが大きいほど、窒素以外の全ての溶存ガスの分圧が大きく、酸化に寄与する全ての溶存ガスの合計分圧が大きい。ヘンリーの法則によれば、酸化に寄与する全ての溶存ガスの合計分圧が大きいほど、酸化に寄与する全ての溶存ガスの合計濃度が大きい。従って、測定した溶存窒素濃度ＤＮが小さいほど、酸化に寄与する全ての溶存ガスの合計濃度が大きい。 Since the saturated dissolved nitrogen concentration is constant, the smaller the measured dissolved nitrogen concentration DN, the larger the difference ΔDN. The larger the difference ΔDN, the larger the partial pressure of all dissolved gases other than nitrogen, and the larger the total partial pressure of all dissolved gases that contribute to oxidation. According to Henry's law, the larger the total partial pressure of all dissolved gases that contribute to oxidation, the greater the total concentration of all dissolved gases that contribute to oxidation. Therefore, the smaller the measured dissolved nitrogen concentration DN, the larger the total concentration of all dissolved gases that contribute to oxidation.
　基板処理装置１は、薬液３の溶存窒素濃度ＤＮを測定する測定部５０と、薬液３に窒素ガスを溶解させる溶解部６０とを備える。制御部９０は、測定部５０によって測定した溶存窒素濃度ＤＮを基に、溶解部６０によって単位時間当たりに薬液３に溶解させる窒素ガスの量を決める。酸化に寄与しない溶存窒素の濃度ＤＮを管理することで、酸化に寄与する全ての溶存ガスの合計濃度を管理できるので、薬液３によるポリシリコン膜のエッチングレートＥＲを精度良く管理できる。以下、薬液３によるポリシリコン膜のエッチングレートＥＲを、単に「エッチングレートＥＲ」とも呼ぶ。 The substrate processing apparatus 1 includes a measuring unit 50 that measures the dissolved nitrogen concentration DN of the chemical liquid 3 and a dissolving unit 60 that dissolves nitrogen gas in the chemical liquid 3. The control unit 90 determines the amount of nitrogen gas to be dissolved in the chemical liquid 3 per unit time by the dissolving unit 60 based on the dissolved nitrogen concentration DN measured by the measuring unit 50. By controlling the concentration DN of dissolved nitrogen that does not contribute to oxidation, the total concentration of all dissolved gases that contribute to oxidation can be controlled, so that the etching rate ER of the polysilicon film by the chemical solution 3 can be controlled accurately. Hereinafter, the etching rate ER of the polysilicon film with the chemical solution 3 will be simply referred to as “etching rate ER”.
　測定部５０は、薬液３の溶存窒素濃度ＤＮを測定する溶存窒素濃度計５１を有する。溶存窒素濃度計５１は、例えば薬液３に超音波を照射することにより、水素ラジカルを発生させる。水素ラジカルが溶存窒素と反応することで、窒素化合物（例えばＮＯＸ －、ＮＨ４ ＋）が生じる。溶存窒素濃度計５１は、溶存窒素由来のイオン量を比抵抗計で測定し、測定したイオン量を基に溶存窒素濃度ＤＮを算出する。溶存窒素濃度計５１は、測定結果を示す信号を制御部９０に送信する。 The measurement unit 50 has a dissolved nitrogen concentration meter 51 that measures the dissolved nitrogen concentration DN of the chemical liquid 3. The dissolved nitrogen concentration meter 51 generates hydrogen radicals by irradiating the chemical liquid 3 with ultrasonic waves, for example. The reaction of hydrogen radicals with dissolved nitrogen produces nitrogen compounds (eg NO X − , NH 4 + ). The dissolved nitrogen concentration meter 51 measures the amount of ions derived from dissolved nitrogen with a resistivity meter and calculates the dissolved nitrogen concentration DN based on the measured amount of ions. The dissolved nitrogen concentration meter 51 transmits a signal indicating the measurement result to the control unit 90.
　溶存窒素濃度計５１は、供給ライン３１と回収ライン４１のどちらに配置されてもよく、両方に配置されてもよいが、本実施形態では供給ライン３１の途中に配置される。供給ライン３１は、貯留部３０から処理部１０に薬液３を供給する。供給ライン３１の途中に溶存窒素濃度計５１が配置されることで、ポリシリコン膜のエッチング時の薬液３の溶存窒素濃度ＤＮを管理でき、エッチングレートＥＲを精度良く管理できる。 The dissolved nitrogen concentration meter 51 may be arranged in either the supply line 31 or the recovery line 41, or both, but in the present embodiment, it is arranged in the middle of the supply line 31. The supply line 31 supplies the chemical liquid 3 from the storage unit 30 to the processing unit 10. By disposing the dissolved nitrogen concentration meter 51 in the middle of the supply line 31, the dissolved nitrogen concentration DN of the chemical liquid 3 at the time of etching the polysilicon film can be controlled, and the etching rate ER can be controlled accurately.
　供給ライン３１は、上述の如く、薬液３の温度を管理する目的で、途中にヒータ３７が配置される循環ライン３２と、第１分岐ライン３３とを有する。循環ライン３２は、貯留部３０から取り出した薬液３を貯留部３０に戻す。循環ライン３２の上流端３２ａは貯留部３０に結合し、循環ライン３２の下流端３２ｂも貯留部３０に結合する。第１分岐ライン３３は、循環ライン３２の第１分岐点３８から分岐し、処理部１０まで延びる。第１分岐ライン３３は、処理部１０毎に設けられる。 As described above, the supply line 31 has the circulation line 32 in which the heater 37 is arranged and the first branch line 33 for the purpose of controlling the temperature of the chemical liquid 3. The circulation line 32 returns the chemical liquid 3 taken out from the storage section 30 to the storage section 30. The upstream end 32a of the circulation line 32 is connected to the storage part 30, and the downstream end 32b of the circulation line 32 is also connected to the storage part 30. The first branch line 33 branches from the first branch point 38 of the circulation line 32 and extends to the processing unit 10. The first branch line 33 is provided for each processing unit 10.
　供給ライン３１が循環ライン３２と第１分岐ライン３３とを有する場合、溶存窒素濃度計５１は循環ライン３２の全ての第１分岐点３８よりも循環ライン３２の上流端３２ａ側に配置される。全ての処理部１０において、ポリシリコン膜のエッチング時の薬液３の溶存窒素濃度ＤＮを管理でき、エッチングレートＥＲを精度良く管理できる。 When the supply line 31 has the circulation line 32 and the first branch line 33, the dissolved nitrogen concentration meter 51 is arranged closer to the upstream end 32a of the circulation line 32 than all the first branch points 38 of the circulation line 32. In all the processing parts 10, the dissolved nitrogen concentration DN of the chemical liquid 3 at the time of etching the polysilicon film can be controlled, and the etching rate ER can be controlled accurately.
　溶存窒素濃度計５１は、循環ライン３２の全ての第１分岐点３８よりも循環ライン３２の上流端３２ａ側に配置される。例えば、溶存窒素濃度計５１は、第２分岐ライン３４に配置される。第２分岐ライン３４は、循環ライン３２の第２分岐点４０から分岐し、貯留部３０まで延びる。なお、溶存窒素濃度計５１は、循環ライン３２の全ての第１分岐点３８よりも循環ライン３２の上流端３２ａ側に配置されればよく、循環ライン３２に配置されてもよい。 The dissolved nitrogen concentration meter 51 is arranged on the upstream end 32a side of the circulation line 32 with respect to all the first branch points 38 of the circulation line 32. For example, the dissolved nitrogen concentration meter 51 is arranged in the second branch line 34. The second branch line 34 branches from the second branch point 40 of the circulation line 32 and extends to the storage section 30. The dissolved nitrogen concentration meter 51 may be arranged on the upstream end 32a side of the circulation line 32 with respect to all the first branch points 38 of the circulation line 32, or may be arranged on the circulation line 32.
　溶解部６０は、薬液３に窒素ガスを溶解させる溶解ユニットを有する。薬液３に窒素ガスを溶解させることにより、薬液３の溶存窒素濃度ＤＮを大きくできる。なお、薬液３の溶存窒素濃度ＤＮが薬液３の飽和溶存窒素濃度を超えることはない。窒素ガスとしては、純度の高いものが用いられ、例えば純度９９．９質量％以上のものが用いられる。 The dissolving section 60 has a dissolving unit that dissolves nitrogen gas in the chemical liquid 3. By dissolving nitrogen gas in the chemical liquid 3, the dissolved nitrogen concentration DN of the chemical liquid 3 can be increased. The dissolved nitrogen concentration DN of the chemical liquid 3 never exceeds the saturated dissolved nitrogen concentration of the chemical liquid 3. As the nitrogen gas, one having a high purity is used, for example, one having a purity of 99.9% by mass or more is used.
　溶解ユニットとしては、例えば、バブリングユニット、パージユニットまたはミキシングユニットなどが用いられる。バブリングユニットは、容器の内部に貯留されている薬液３の内部に、窒素ガスを吐出する吐出口が設けられるバブリング配管を有する。パージユニットは、容器の内部に貯留されている薬液３の上方に形成される上部空間に、窒素ガスを吐出する吐出口が設けられるパージ配管を有する。パージ配管は、窒素ガスを吐出することにより、容器の上部空間のガスを窒素ガスに置き換える。ミキシングユニットは、薬液３が流れる薬液配管の内部に窒素ガスを供給するガス配管と、薬液配管の内部において窒素ガスと薬液３とを撹拌する撹拌翼とを有する。 As the dissolution unit, for example, a bubbling unit, a purge unit or a mixing unit is used. The bubbling unit has a bubbling pipe provided with a discharge port for discharging nitrogen gas inside the chemical liquid 3 stored in the container. The purge unit has a purge pipe provided with a discharge port for discharging nitrogen gas in an upper space formed above the chemical liquid 3 stored in the container. The purge pipe discharges nitrogen gas to replace the gas in the upper space of the container with nitrogen gas. The mixing unit has a gas pipe for supplying nitrogen gas into the chemical liquid pipe through which the chemical liquid 3 flows, and a stirring blade for stirring the nitrogen gas and the chemical liquid 3 inside the chemical liquid pipe.
　溶解ユニットは、薬液３に窒素ガスを溶解させる機能を有すればよく、薬液３に酸素ガスを溶解させる機能をさらに有してもよい。薬液３に酸素ガスを溶解させることにより、薬液３の溶存酸素濃度を大きくできる。薬液３の溶存酸素濃度が大きくなると、薬液３の溶存酸素分圧が大きくなるので、薬液３の溶存窒素分圧が小さくなる。その結果、薬液３の溶存窒素濃度ＤＮが小さくなる。酸素ガスは、例えば空気として供給される。空気としては、露点が－１０℃以下であるドライエアが用いられる。 The dissolution unit only needs to have a function of dissolving nitrogen gas in the chemical liquid 3, and may further have a function of dissolving oxygen gas in the chemical liquid 3. By dissolving oxygen gas in the chemical liquid 3, the dissolved oxygen concentration of the chemical liquid 3 can be increased. When the dissolved oxygen concentration of the chemical liquid 3 increases, the dissolved oxygen partial pressure of the chemical liquid 3 increases, so that the dissolved nitrogen partial pressure of the chemical liquid 3 decreases. As a result, the dissolved nitrogen concentration DN of the chemical liquid 3 becomes smaller. The oxygen gas is supplied as air, for example. As air, dry air having a dew point of -10°C or lower is used.
　溶解ユニットは、窒素ガスと同様にして、酸素ガスを薬液３に溶解させる。例えば、バブリングユニットは、容器の内部に貯留されている薬液３の内部に、酸素ガスを吐出する吐出口が設けられるバブリング配管を有する。パージユニットは、容器の内部に貯留されている薬液３の上方に形成される上部空間に、酸素ガスを吐出する吐出口が設けられるパージ配管を有する。パージ配管は、酸素ガスを吐出することにより、容器の上部空間のガスを酸素ガスに置き換える。ミキシングユニットは、薬液３が流れる薬液配管の内部に酸素ガスを供給するガス配管と、薬液配管の内部において酸素ガスと薬液３とを撹拌する撹拌翼とを有する。 The dissolving unit dissolves oxygen gas in the chemical liquid 3 in the same manner as nitrogen gas. For example, the bubbling unit has a bubbling pipe provided with a discharge port for discharging oxygen gas inside the chemical liquid 3 stored in the container. The purge unit has a purge pipe provided with a discharge port for discharging oxygen gas in an upper space formed above the chemical liquid 3 stored in the container. The purge pipe discharges oxygen gas to replace the gas in the upper space of the container with oxygen gas. The mixing unit has a gas pipe for supplying oxygen gas into the chemical liquid pipe through which the chemical liquid 3 flows, and a stirring blade for stirring the oxygen gas and the chemical liquid 3 inside the chemical liquid pipe.
　溶解ユニットは、貯留部３０、供給ライン３１、処理部１０、および回収ライン４１から選ばれる１つ以上に設置される。なお、これらのうちから選ばれる１つに、複数の溶解ユニットが設置されてもよい。例えば、貯留部３０に、バブリングユニットとパージユニットの両方が設置されてもよい。 The dissolution unit is installed in one or more selected from the storage unit 30, the supply line 31, the processing unit 10, and the recovery line 41. Note that a plurality of melting units may be installed in one selected from these. For example, both the bubbling unit and the purging unit may be installed in the storage unit 30.
　溶解部６０は、例えば、貯留部用溶解ユニット６１と、回収ライン用溶解ユニット６４Ａ、６４Ｂと、処理部用溶解ユニット６７とを有する。貯留部用溶解ユニット６１は、貯留部３０に設置される溶解ユニットである。回収ライン用溶解ユニット６４Ａ、６４Ｂは、回収ライン４１に設置される溶解ユニットである。処理部用溶解ユニット６７は、処理部１０に設置される溶解ユニットである。 The dissolving section 60 has, for example, a storing section dissolving unit 61, recovery line dissolving units 64A and 64B, and a processing section dissolving unit 67. The storage unit dissolution unit 61 is a dissolution unit installed in the storage unit 30. The recovery line dissolution units 64A and 64B are dissolution units installed in the recovery line 41. The processing unit dissolution unit 67 is a dissolution unit installed in the processing unit 10.
　貯留部用溶解ユニット６１は、制御部９０による制御下で、貯留部３０に窒素ガスを供給することにより、薬液３に窒素ガスを溶解させる。制御部９０は、測定部５０によって測定した溶存窒素濃度ＤＮを基に、貯留部用溶解ユニット６１によって単位時間当たりに薬液３に溶解させる窒素ガスの量を決める。 Under the control of the control unit 90, the storage unit dissolution unit 61 supplies nitrogen gas to the storage unit 30 to dissolve the nitrogen gas in the chemical liquid 3. The control unit 90 determines the amount of nitrogen gas to be dissolved in the chemical liquid 3 per unit time by the storage unit dissolution unit 61 based on the dissolved nitrogen concentration DN measured by the measurement unit 50.
　例えば、貯留部用溶解ユニット６１は、バブリング配管６２を含む。バブリング配管６２は、薬液３の内部に窒素ガスを吐出することにより、薬液３の内部に窒素ガスの気泡を発生させる。バブリング配管６２の代わりに、パージ配管が用いられる場合に比べて、窒素ガスの使用量を低減できる。窒素ガスが貯留部３０の内部から貯留部３０の外部に排気されるまでの間に、窒素ガスと薬液３とを効率良く接触できるからである。 For example, the storage unit dissolution unit 61 includes a bubbling pipe 62. The bubbling pipe 62 generates nitrogen gas bubbles inside the chemical liquid 3 by discharging nitrogen gas into the chemical liquid 3. The amount of nitrogen gas used can be reduced as compared with the case where a purge pipe is used instead of the bubbling pipe 62. This is because the nitrogen gas and the chemical liquid 3 can be efficiently brought into contact with each other before the nitrogen gas is exhausted from the inside of the storage portion 30 to the outside of the storage portion 30.
　バブリング配管６２の途中には、流量調整弁７２が配置される。流量調整弁７２は、制御部９０による制御下で、バブリング配管６２から薬液３の内部に吐出される窒素ガスの流量を調整する。制御部９０は、測定部５０によって測定した溶存窒素濃度ＤＮを基に、バブリング配管６２から薬液３の内部に吐出される窒素ガスの流量を決める。窒素ガスの流量が多いほど、単位時間当たりに薬液３に溶解させる窒素ガスの量が増え、薬液３の溶存窒素濃度ＤＮが大きくなる。なお、溶存窒素濃度ＤＮが、飽和溶存窒素濃度を超えることはない。 A flow rate adjusting valve 72 is arranged in the middle of the bubbling pipe 62. The flow rate adjusting valve 72 adjusts the flow rate of the nitrogen gas discharged from the bubbling pipe 62 into the chemical liquid 3 under the control of the control unit 90. The control unit 90 determines the flow rate of the nitrogen gas discharged from the bubbling pipe 62 into the chemical liquid 3 based on the dissolved nitrogen concentration DN measured by the measuring unit 50. As the flow rate of nitrogen gas increases, the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time increases, and the dissolved nitrogen concentration DN of the chemical liquid 3 increases. The dissolved nitrogen concentration DN never exceeds the saturated dissolved nitrogen concentration.
　また、貯留部用溶解ユニット６１は、制御部９０による制御下で、貯留部３０に酸素ガスを供給することにより、薬液３に酸素ガスを溶解させる。制御部９０は、測定部５０によって測定した溶存窒素濃度ＤＮを基に、貯留部用溶解ユニット６１によって単位時間当たりに薬液３に溶解させる酸素ガスの量を決める。 Further, the storage unit dissolution unit 61 supplies oxygen gas to the storage unit 30 under the control of the control unit 90 to dissolve the oxygen gas in the chemical liquid 3. The control unit 90 determines the amount of oxygen gas to be dissolved in the chemical liquid 3 per unit time by the storage unit dissolution unit 61 based on the dissolved nitrogen concentration DN measured by the measurement unit 50.
　例えば、貯留部用溶解ユニット６１は、バブリング配管６３を含む。バブリング配管６３は、薬液３の内部に酸素ガスを吐出することにより、薬液３の内部に酸素ガスの気泡を発生させる。バブリング配管６３の代わりに、パージ配管が用いられる場合に比べて、酸素ガスの使用量を低減できる。酸素ガスが貯留部３０の内部から貯留部３０の外部に排気されるまでの間に、酸素ガスと薬液３とを効率良く接触できるからである。 For example, the storage unit dissolution unit 61 includes a bubbling pipe 63. The bubbling pipe 63 discharges oxygen gas into the chemical liquid 3 to generate bubbles of oxygen gas inside the chemical liquid 3. The amount of oxygen gas used can be reduced as compared with the case where a purge pipe is used instead of the bubbling pipe 63. This is because the oxygen gas and the chemical liquid 3 can be efficiently brought into contact with each other before the oxygen gas is exhausted from the inside of the reservoir 30 to the outside of the reservoir 30.
　バブリング配管６３の途中には、流量調整弁７３が配置される。流量調整弁７３は、制御部９０による制御下で、バブリング配管６３から薬液３の内部に吐出される酸素ガスの流量を調整する。制御部９０は、測定部５０によって測定した溶存窒素濃度ＤＮを基に、バブリング配管６３から薬液３の内部に吐出される酸素ガスの流量を決める。酸素ガスの流量が多いほど、単位時間当たりに薬液３に溶解させる酸素ガスの量が増え、薬液３の溶存窒素濃度ＤＮが小さくなる。 A flow rate adjusting valve 73 is arranged in the middle of the bubbling pipe 63. The flow rate adjusting valve 73 adjusts the flow rate of the oxygen gas discharged from the bubbling pipe 63 into the chemical liquid 3 under the control of the control unit 90. The control unit 90 determines the flow rate of the oxygen gas discharged from the bubbling pipe 63 into the chemical liquid 3 based on the dissolved nitrogen concentration DN measured by the measurement unit 50. As the flow rate of oxygen gas increases, the amount of oxygen gas dissolved in the chemical liquid 3 per unit time increases, and the dissolved nitrogen concentration DN of the chemical liquid 3 decreases.
　なお、本実施形態では貯留部用溶解ユニット６１のみが薬液３に酸素ガスを溶解させる機能を有するが、本開示の技術はこれに限定されない。例えば、回収ライン用溶解ユニット６４Ａ、６４Ｂが薬液３に酸素ガスを溶解させる機能を有してもよい。また、処理部用溶解ユニット６７が薬液３に酸素ガスを溶解させる機能を有してもよい。 Note that in the present embodiment, only the storage unit dissolution unit 61 has a function of dissolving oxygen gas in the chemical liquid 3, but the technique of the present disclosure is not limited to this. For example, the recovery line dissolution units 64A and 64B may have a function of dissolving oxygen gas in the chemical liquid 3. Further, the processing unit dissolution unit 67 may have a function of dissolving oxygen gas in the chemical liquid 3.
　回収ライン用溶解ユニット６４Ａ、６４Ｂは、図１に示すように、回収ライン４１の主ライン４２に設けられる。一の回収ライン用溶解ユニット６４Ａは、最も上流側の副ライン４３よりもさらに上流側に設けられる。他の一の回収ライン用溶解ユニット６４Ｂは、最も下流側の副ライン４３よりもさらに下流側に設けられる。 The recovery line dissolution units 64A and 64B are provided in the main line 42 of the recovery line 41, as shown in FIG. The one recovery line dissolution unit 64A is provided further upstream than the most upstream sub line 43. The other recovery line dissolving unit 64B is provided further downstream than the most downstream side sub-line 43.
　回収ライン用溶解ユニット６４Ａは、図８に示すように、例えばパージユニットである。回収ライン用溶解ユニット６４Ａは、パージ配管６５を有する。パージ配管６５は、回収ライン４１の内部の上部空間に窒素ガスを吐出することにより、回収ライン４１の上部空間のガスを窒素ガスに置き換える。 The recovery line dissolution unit 64A is, for example, a purge unit, as shown in FIG. The recovery line dissolution unit 64A has a purge pipe 65. The purge pipe 65 replaces the gas in the upper space of the recovery line 41 with the nitrogen gas by discharging the nitrogen gas into the upper space inside the recovery line 41.
　パージ配管６５の途中には、流量調整弁６６が設けられる。流量調整弁６６は、制御部９０による制御下で、パージ配管６５から回収ライン４１の内部に吐出される窒素ガスの流量を調整する。窒素ガスの流量が多いほど、単位時間当たりに薬液３に溶解させる窒素ガスの量が増え、薬液３の溶存窒素濃度ＤＮが大きくなる。 A flow rate adjustment valve 66 is provided in the middle of the purge pipe 65. The flow rate adjusting valve 66 adjusts the flow rate of the nitrogen gas discharged from the purge pipe 65 into the recovery line 41 under the control of the control unit 90. As the flow rate of nitrogen gas increases, the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time increases, and the dissolved nitrogen concentration DN of the chemical liquid 3 increases.
　回収ライン用溶解ユニット６４Ａ、６４Ｂは、制御部９０による制御下で、回収ライン４１に窒素ガスを供給することにより、薬液３に窒素ガスを溶解させる。制御部９０は、測定部５０によって測定した溶存窒素濃度ＤＮを基に、回収ライン用溶解ユニット６４Ａ、６４Ｂによって単位時間当たりに薬液３に溶解させる窒素ガスの量を決める。 Under the control of the controller 90, the recovery line dissolving units 64A and 64B supply nitrogen gas to the recovery line 41 to dissolve the nitrogen gas in the chemical liquid 3. The control unit 90 determines the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time by the recovery line dissolution units 64A and 64B based on the dissolved nitrogen concentration DN measured by the measurement unit 50.
　薬液３は、処理部１０の処理容器１１の内部に吐出され、処理部１０から貯留部３０まで延びる回収ライン４１を通り、貯留部３０まで戻る。回収ライン４１は、供給ライン３１とは異なり、薬液３が常に流れない。回収ライン４１の内部には空間が存在するので、空間の酸素ガスが薬液３に溶解することがある。従って、薬液３が回収ライン４１を通る間に、薬液３の溶存酸素濃度が大きくなり、薬液３の溶存窒素濃度ＤＮが小さくなることがある。 The chemical liquid 3 is discharged into the processing container 11 of the processing unit 10, passes through the recovery line 41 extending from the processing unit 10 to the storage unit 30, and returns to the storage unit 30. Unlike the supply line 31, the recovery line 41 does not always flow the chemical liquid 3. Since there is a space inside the recovery line 41, the oxygen gas in the space may dissolve in the chemical liquid 3. Therefore, while the chemical liquid 3 passes through the recovery line 41, the dissolved oxygen concentration of the chemical liquid 3 may increase and the dissolved nitrogen concentration DN of the chemical liquid 3 may decrease.
　回収ライン用溶解ユニット６４Ａ、６４Ｂは、回収ライン４１の途中で薬液３に窒素ガスを溶解させる。回収ライン４１から貯留部３０に戻る薬液３と、貯留部３０に予め貯留されている薬液３とで、溶存窒素濃度ＤＮの差を小さくできる。従って、貯留部３０の内部における薬液３の溶存窒素濃度ＤＮの均一性を向上できる。 The recovery line dissolution units 64A and 64B dissolve nitrogen gas in the chemical liquid 3 in the middle of the recovery line 41. The difference in the dissolved nitrogen concentration DN between the chemical liquid 3 returning from the recovery line 41 to the storage unit 30 and the chemical liquid 3 stored in advance in the storage unit 30 can be reduced. Therefore, the uniformity of the dissolved nitrogen concentration DN of the chemical liquid 3 inside the reservoir 30 can be improved.
　回収ライン用溶解ユニット６４Ａは、最も上流側の副ライン４３よりもさらに上流側に設けられる。回収ライン４１の上流部に窒素ガスを供給できるので、回収ライン４１を流れる薬液３と酸素ガスとの接触を抑制でき、薬液３の溶存窒素濃度ＤＮの低下を抑制できる。 The recovery line dissolution unit 64A is provided further upstream than the most upstream sub line 43. Since nitrogen gas can be supplied to the upstream portion of the recovery line 41, contact between the chemical liquid 3 flowing through the recovery line 41 and oxygen gas can be suppressed, and a decrease in the dissolved nitrogen concentration DN of the chemical liquid 3 can be suppressed.
　一方、回収ライン用溶解ユニット６４Ｂは、最も下流側の副ライン４３よりもさらに下流側に設けられる。回収ライン４１の下流部に窒素ガスを供給できるので、一旦低下した溶存窒素濃度ＤＮを再び元の値まで戻すことができる。下流側の回収ライン用溶解ユニット６４Ｂは、例えば上流側の回収ライン用溶解ユニット６４Ａで薬液３の溶存窒素濃度ＤＮの低下を十分に抑制できない場合に、窒素ガスを回収ライン４１の内部に吐出する。 On the other hand, the recovery line dissolution unit 64B is provided further downstream than the most downstream sub line 43. Since nitrogen gas can be supplied to the downstream portion of the recovery line 41, the once lowered dissolved nitrogen concentration DN can be returned to the original value again. The downstream recovery line dissolution unit 64B, for example, discharges nitrogen gas into the recovery line 41 when the upstream recovery line dissolution unit 64A cannot sufficiently suppress the decrease in the dissolved nitrogen concentration DN of the chemical liquid 3. ..
　制御部９０は、溶存窒素濃度計５１によって測定した溶存窒素濃度ＤＮを基に、回収ライン用溶解ユニット６４Ａ、６４Ｂによって単位時間当たりに薬液３に溶解させる窒素ガスの量を決める。溶存窒素濃度計５１は、本実施形態では供給ライン３１に設置されるが、回収ライン４１に設置されてもよい。 The control unit 90 determines the amount of nitrogen gas to be dissolved in the chemical liquid 3 per unit time by the recovery line dissolution units 64A and 64B based on the dissolved nitrogen concentration DN measured by the dissolved nitrogen concentration meter 51. Although the dissolved nitrogen concentration meter 51 is installed in the supply line 31 in the present embodiment, it may be installed in the recovery line 41.
　溶存窒素濃度計５１が回収ライン４１に設置されていれば、回収ライン４１における薬液３の溶存窒素濃度ＤＮを測定できる。従って、回収ライン４１から貯留部３０に戻る薬液３と、貯留部３０に予め貯留されている薬液３とで、溶存窒素濃度ＤＮの差を小さくすることが容易である。 If the dissolved nitrogen concentration meter 51 is installed in the recovery line 41, the dissolved nitrogen concentration DN of the chemical liquid 3 in the recovery line 41 can be measured. Therefore, it is easy to reduce the difference in the dissolved nitrogen concentration DN between the chemical liquid 3 returning from the recovery line 41 to the storage portion 30 and the chemical liquid 3 stored in advance in the storage portion 30.
　溶存窒素濃度計５１は、回収ライン４１に設置される場合、回収ライン用溶解ユニット６４Ａの上流側に配置されてもよいし、回収ライン用溶解ユニット６４Ｂの下流側に配置されてもよいし、２つの回収ライン用溶解ユニット６４Ａ、６４Ｂの間に配置されてもよい。いずれにしろ、回収ライン４１から貯留部３０に戻る薬液３と、貯留部３０に予め貯留されている薬液３とで、溶存窒素濃度ＤＮの差を小さくすることが容易である。 When installed in the recovery line 41, the dissolved nitrogen concentration meter 51 may be arranged upstream of the recovery line dissolution unit 64A, or may be disposed downstream of the recovery line dissolution unit 64B, It may be disposed between the two recovery line dissolution units 64A and 64B. In any case, it is easy to reduce the difference in the dissolved nitrogen concentration DN between the chemical liquid 3 returning from the recovery line 41 to the storage portion 30 and the chemical liquid 3 stored in advance in the storage portion 30.
　ところで、上述の如く回収ライン４１の内部で酸素ガスが薬液３に溶解する他、処理部１０の処理容器１１の内部で酸素ガスが薬液３に溶解することもある。処理容器１１の内部での溶存窒素濃度ＤＮの低下を抑制すべく、処理部用溶解ユニット６７が用いられる。 By the way, as described above, in addition to the oxygen gas dissolving in the chemical liquid 3 inside the recovery line 41, the oxygen gas may dissolve in the chemical liquid 3 inside the processing container 11 of the processing unit 10. The processing unit dissolution unit 67 is used in order to suppress a decrease in the dissolved nitrogen concentration DN inside the processing container 11.
　処理部用溶解ユニット６７は、制御部９０による制御下で、処理容器１１の内部に窒素ガスを供給することにより、薬液３に窒素ガスを溶解させる。制御部９０は、測定部５０によって測定した溶存窒素濃度ＤＮを基に、処理部用溶解ユニット６７によって単位時間当たりに薬液３に溶解させる窒素ガスの量を決める。 Under the control of the control unit 90, the processing unit dissolution unit 67 supplies nitrogen gas into the processing container 11 to dissolve the nitrogen gas in the chemical liquid 3. The control unit 90 determines the amount of nitrogen gas to be dissolved in the chemical liquid 3 per unit time by the processing unit dissolution unit 67 based on the dissolved nitrogen concentration DN measured by the measurement unit 50.
　例えば、処理部用溶解ユニット６７は、パージ配管６８を含む。パージ配管６８は、処理容器１１の内部に窒素ガスを吐出することにより、処理容器１１の内部のガスを窒素ガスに置き換える。パージ配管６８の途中には、流量調整弁７８が配置される。流量調整弁７８は、制御部９０による制御下で、パージ配管６８から処理容器１１の内部に吐出される窒素ガスの流量を調整する。制御部９０は、測定部５０によって測定した溶存窒素濃度ＤＮを基に、パージ配管６８から処理容器１１の内部に吐出される窒素ガスの流量を決める。窒素ガスの流量が多いほど、単位時間当たりに薬液３に溶解させる窒素ガスの量が増え、薬液３の溶存窒素濃度ＤＮが大きくなる。なお、溶存窒素濃度ＤＮが、飽和溶存窒素濃度を超えることはない。 For example, the processing unit dissolution unit 67 includes a purge pipe 68. The purge pipe 68 discharges nitrogen gas into the processing container 11 to replace the gas inside the processing container 11 with nitrogen gas. A flow rate adjusting valve 78 is arranged in the middle of the purge pipe 68. The flow rate adjusting valve 78 adjusts the flow rate of the nitrogen gas discharged from the purge pipe 68 into the processing container 11 under the control of the control unit 90. The control unit 90 determines the flow rate of the nitrogen gas discharged from the purge pipe 68 into the processing container 11 based on the dissolved nitrogen concentration DN measured by the measurement unit 50. As the flow rate of nitrogen gas increases, the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time increases, and the dissolved nitrogen concentration DN of the chemical liquid 3 increases. The dissolved nitrogen concentration DN never exceeds the saturated dissolved nitrogen concentration.
　薬液３の溶存窒素濃度ＤＮを調整する溶解ユニットとして、貯留部用溶解ユニット６１と、回収ライン用溶解ユニット６４Ａ、６４Ｂと、処理部用溶解ユニット６７のうちのどの溶解ユニットを使用するのかは、例えば、第１分岐ライン３３の開閉弁３９が開状態か閉状態かに基づいて決定される。開閉弁３９が開状態である場合、薬液３が処理部１０の処理容器１１から回収ライン４１に流れ込む。一方、開閉弁３９が閉状態である場合、薬液３が処理部１０の処理容器１１から回収ライン４１に流れ込まない。 As the dissolution unit for adjusting the dissolved nitrogen concentration DN of the chemical liquid 3, which of the storage unit dissolution unit 61, the recovery line dissolution units 64A and 64B, and the processing unit dissolution unit 67 is to be used is For example, it is determined based on whether the open/close valve 39 of the first branch line 33 is open or closed. When the open/close valve 39 is open, the chemical liquid 3 flows into the recovery line 41 from the processing container 11 of the processing unit 10. On the other hand, when the open/close valve 39 is closed, the chemical liquid 3 does not flow from the processing container 11 of the processing unit 10 into the recovery line 41.
　先ず、開閉弁３９が開状態である場合、つまり、薬液３が処理部１０の処理容器１１から回収ライン４１に流れ込み中である場合について説明する。この場合、先ず、上流側の回収ライン用溶解ユニット６４Ａが、回収ライン４１の内部に窒素ガスを吐出し、薬液３の溶存窒素濃度ＤＮの低下を抑制する。その効果が十分ではない場合、下流側の回収ライン用溶解ユニット６４Ｂが、窒素ガスを回収ライン４１の内部に吐出し、低下した溶存窒素濃度ＤＮを元の値に戻す。下流側の回収ライン用溶解ユニット６４Ｂに代えて、または下流側の回収ライン用溶解ユニット６４Ｂと共に、処理部用溶解ユニット６７が使用されてもよい。薬液３が処理部１０から回収ライン４１に流れ込み中である場合、その直前と同じ設定で貯留部用溶解ユニット６１は制御される。 First, the case where the on-off valve 39 is in the open state, that is, the case where the chemical liquid 3 is flowing into the recovery line 41 from the processing container 11 of the processing unit 10 will be described. In this case, first, the recovery line dissolution unit 64A on the upstream side discharges the nitrogen gas into the recovery line 41 to suppress a decrease in the dissolved nitrogen concentration DN of the chemical liquid 3. When the effect is not sufficient, the downstream recovery line dissolution unit 64B discharges the nitrogen gas into the recovery line 41 to restore the lowered dissolved nitrogen concentration DN to the original value. The processing unit dissolution unit 67 may be used in place of the downstream recovery line dissolution unit 64B or together with the downstream recovery line dissolution unit 64B. When the chemical liquid 3 is flowing into the recovery line 41 from the processing unit 10, the storage unit dissolution unit 61 is controlled with the same settings as immediately before that.
　次に、開閉弁３９が閉状態である場合、つまり、薬液３が処理部１０の処理容器１１から回収ライン４１に流れ込み中ではない場合について説明する。この場合、処理容器１１の内部で薬液３が流れないので、処理部用溶解ユニット６７は処理容器１１の内部に窒素ガスを吐出しない。また、この場合、回収ライン４１の内部で薬液３が流れないので、回収ライン用溶解ユニット６４Ａ、６４Ｂは回収ライン４１の内部に窒素ガスを吐出しない。この場合、貯留部用溶解ユニット６１が、溶存窒素濃度ＤＮを調整する。 Next, the case where the open/close valve 39 is closed, that is, the case where the chemical liquid 3 is not flowing from the processing container 11 of the processing unit 10 into the recovery line 41 will be described. In this case, since the chemical liquid 3 does not flow inside the processing container 11, the processing unit dissolution unit 67 does not discharge the nitrogen gas into the processing container 11. Further, in this case, since the chemical liquid 3 does not flow inside the recovery line 41, the recovery line dissolution units 64A and 64B do not discharge the nitrogen gas into the recovery line 41. In this case, the storage unit dissolution unit 61 adjusts the dissolved nitrogen concentration DN.
　図４は、一実施形態に係る基板処理方法の別の一部を示すフローチャートである。図４に示す工程Ｓ１１１～Ｓ１１３は、予め定められた時間毎に繰り返し行われる。図４に示す工程Ｓ１１１～Ｓ１１３は、図３に示す工程Ｓ１０１～Ｓ１０６と並行して行われてもよいし、図３に示す工程Ｓ１０１～Ｓ１０６の中断時に行われてもよい。 FIG. 4 is a flowchart showing another part of the substrate processing method according to the embodiment. Steps S111 to S113 shown in FIG. 4 are repeated at predetermined time intervals. The steps S111 to S113 shown in FIG. 4 may be performed in parallel with the steps S101 to S106 shown in FIG. 3, or may be performed when the steps S101 to S106 shown in FIG. 3 are interrupted.
　基板処理方法は、薬液３の溶存窒素濃度ＤＮを測定する工程Ｓ１１１を有する。この工程Ｓ１１１では、測定部５０が、薬液３の溶存窒素濃度ＤＮを測定し、測定結果を示す信号を制御部９０に送信する。 The substrate processing method has a step S111 of measuring the dissolved nitrogen concentration DN of the chemical liquid 3. In step S111, the measurement unit 50 measures the dissolved nitrogen concentration DN of the chemical liquid 3 and sends a signal indicating the measurement result to the control unit 90.
　基板処理方法は、測定した溶存窒素濃度ＤＮを基に、単位時間当たりに薬液３に溶解させる窒素ガスの量を決める工程Ｓ１１２を有する。この工程Ｓ１１２では、制御部９０が、溶解部６０によって単位時間当たりに薬液３に溶解させる窒素ガスの量を決める。制御部９０は、溶解部６０を構成する溶解ユニット毎に、溶解ユニットが設置される場所における窒素ガスの流量を決めることで、溶解ユニットによって単位時間当たりに薬液３に溶解させる窒素ガスの量を決める。この量を、「溶解量」とも呼ぶ。 The substrate processing method has a step S112 of determining the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time based on the measured dissolved nitrogen concentration DN. In this step S112, the control unit 90 determines the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time by the dissolution unit 60. The control unit 90 determines the amount of nitrogen gas to be dissolved in the chemical liquid 3 per unit time by the dissolution unit by determining the flow rate of nitrogen gas at the location where the dissolution unit is installed for each dissolution unit that constitutes the dissolution unit 60. Decide This amount is also called "dissolved amount".
　基板処理方法は、決めた量の窒素ガスを薬液３に溶解させる工程Ｓ１１３とを有する。この工程Ｓ１１３では、溶解部６０が、制御部９０による制御下で、薬液３に窒素ガスを溶解させる。制御部９０は、溶解ユニット毎に決めた流量の窒素ガスを、それぞれの溶解ユニットが設置される場所に供給する。 The substrate processing method includes a step S113 of dissolving a predetermined amount of nitrogen gas in the chemical liquid 3. In this step S113, the dissolving section 60 causes the chemical solution 3 to dissolve nitrogen gas under the control of the control section 90. The controller 90 supplies the nitrogen gas at a flow rate determined for each melting unit to the place where each melting unit is installed.
　本実施形態によれば、酸化に寄与しない溶存窒素の濃度ＤＮを管理することで、酸化に寄与する全ての溶存ガスの合計濃度を管理できるので、エッチングレートＥＲを精度良く管理できる。 According to the present embodiment, by controlling the concentration DN of dissolved nitrogen that does not contribute to oxidation, the total concentration of all dissolved gases that contribute to oxidation can be controlled, so that the etching rate ER can be accurately controlled.
　図５は、溶解量を決定する工程の一例を示すフローチャートである。図５に示す工程Ｓ１２１～Ｓ１２５は、制御部９０によって実施される。 FIG. 5 is a flowchart showing an example of the process of determining the dissolution amount. The steps S121 to S125 shown in FIG. 5 are performed by the control unit 90.
　先ず、制御部９０は、測定した溶存窒素濃度ＤＮが設定値ＤＮ１以上であるか否かを判定する（Ｓ１２１）。設定値ＤＮ１は、下限値であって、エッチングレートＥＲを基に予め決められる。設定値ＤＮ１は、エッチングレートＥＲが所望の範囲内に収まるように決められる。設定値ＤＮ１の詳細な決定方法については、後述する。 First, the control unit 90 determines whether or not the measured dissolved nitrogen concentration DN is equal to or higher than the set value DN1 (S121). The set value DN1 is a lower limit value and is predetermined based on the etching rate ER. The set value DN1 is determined so that the etching rate ER falls within a desired range. A detailed method of determining the set value DN1 will be described later.
　測定した溶存窒素濃度ＤＮが設定値ＤＮ１よりも小さい場合（Ｓ１２１、ＮＯ）、制御部９０は溶解部６０によって単位時間当たりに薬液３に溶解させる窒素ガスの量を増やす（Ｓ１２２）。次回以降、溶存窒素濃度ＤＮを大きくでき、溶存窒素濃度ＤＮを設定値ＤＮ１以上に制御できる。その後、制御部９０は、今回の処理を終了する。 When the measured dissolved nitrogen concentration DN is smaller than the set value DN1 (S121, NO), the control unit 90 increases the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time by the dissolution unit 60 (S122). From the next time onward, the dissolved nitrogen concentration DN can be increased, and the dissolved nitrogen concentration DN can be controlled to be equal to or higher than the set value DN1. After that, the control unit 90 ends this processing.
　なお、Ｓ１２２において溶解量を増やす溶解ユニットの数は、１つでもよいし、複数でもよい。複数の溶解ユニットのうち、どの溶解ユニットの溶解量を増やすのかは、例えば、既述の如く、第１分岐ライン３３の開閉弁３９が開状態か閉状態かに基づき決定される。なお、複数の溶解ユニットのうち、どの溶解ユニットの溶解量を増やすのかは、異なる場所に設置される複数の溶存窒素濃度計５１の測定結果に基づき決定されてもよい。 Note that the number of dissolution units that increase the dissolution amount in S122 may be one or more. Which dissolution unit to increase the dissolution amount of the plurality of dissolution units is determined, for example, based on whether the on-off valve 39 of the first branch line 33 is in the open state or the closed state, as described above. Note that which of the plurality of dissolution units is to be increased in dissolution amount may be determined based on the measurement results of the plurality of dissolved nitrogen concentration meters 51 installed at different locations.
　一方、測定した溶存窒素濃度ＤＮが設定値ＤＮ１以上である場合（Ｓ１２１、ＹＥＳ）、制御部９０は測定した溶存窒素濃度ＤＮが設定値ＤＮ２以下であるか否かを判定する（Ｓ１２３）。設定値ＤＮ２は、上限値であって、設定値ＤＮ１と同じ値であるか、設定値ＤＮ１よりも大きい値である。設定値ＤＮ２は、エッチングレートＥＲを基に予め決められる。設定値ＤＮ２は、エッチングレートＥＲが所望の範囲内に収まるように決められる。設定値ＤＮ２の詳細な決定方法については、後述する。 On the other hand, when the measured dissolved nitrogen concentration DN is equal to or higher than the set value DN1 (S121, YES), the control unit 90 determines whether the measured dissolved nitrogen concentration DN is equal to or lower than the set value DN2 (S123). The set value DN2 is an upper limit value and is the same value as the set value DN1 or a value larger than the set value DN1. The set value DN2 is predetermined based on the etching rate ER. The set value DN2 is determined so that the etching rate ER falls within a desired range. A detailed method of determining the set value DN2 will be described later.
　測定した溶存窒素濃度ＤＮが設定値ＤＮ２よりも大きい場合（Ｓ１２３、ＮＯ）、制御部９０は溶解部６０によって単位時間当たりに薬液３に溶解させる窒素ガスの量を減らす（Ｓ１２４）。次回以降、溶存窒素濃度ＤＮを小さくでき、溶存窒素濃度ＤＮを設定値ＤＮ２以下に制御できる。その後、制御部９０は、今回の処理を終了する。 When the measured dissolved nitrogen concentration DN is larger than the set value DN2 (S123, NO), the control unit 90 reduces the amount of nitrogen gas dissolved in the chemical liquid 3 by the dissolving unit 60 per unit time (S124). From the next time onward, the dissolved nitrogen concentration DN can be reduced, and the dissolved nitrogen concentration DN can be controlled to be equal to or lower than the set value DN2. After that, the control unit 90 ends this processing.
　なお、Ｓ１２４において溶解量を減らす溶解ユニットの数は、１つでもよいし、複数でもよい。複数の溶解ユニットのうち、どの溶解ユニットの溶解量を減らすのかは、例えば、既述の如く、第１分岐ライン３３の開閉弁３９が開状態か閉状態かに基づき決定される。なお、複数の溶解ユニットのうち、どの溶解ユニットの溶解量を減らすのかは、異なる場所に設置される複数の溶存窒素濃度計５１の測定結果に基づき決定されてもよい。 Note that the number of dissolution units that reduce the dissolution amount in S124 may be one or more. Of the plurality of dissolving units, which dissolving unit to reduce the dissolving amount is determined based on whether the on-off valve 39 of the first branch line 33 is in the open state or the closed state, as described above. It should be noted that which of the plurality of dissolution units is to be reduced in dissolution amount may be determined based on the measurement results of the plurality of dissolved nitrogen concentration meters 51 installed at different locations.
　一方、測定した溶存窒素濃度ＤＮが設定値ＤＮ２以下である場合（Ｓ１２３、ＹＥＳ）、制御部９０は溶解部６０によって単位時間当たりに薬液３に溶解させる窒素ガスの量を維持する（Ｓ１２５）。次回以降、溶存窒素濃度ＤＮを同程度に維持できる。その後、制御部９０は、今回の処理を終了する。 On the other hand, when the measured dissolved nitrogen concentration DN is equal to or lower than the set value DN2 (S123, YES), the control unit 90 maintains the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time by the dissolution unit 60 (S125). From the next time onward, the dissolved nitrogen concentration DN can be maintained at the same level. After that, the control unit 90 ends this processing.
　本実施形態によれば、溶存窒素濃度ＤＮをフィードバック制御するので、エッチングレートＥＲを所望の範囲内に収めることができる。図５では、薬液３の溶存窒素濃度ＤＮが制御量であり、単位時間当たりに薬液３に溶解させる窒素ガスの量が操作量である。 According to the present embodiment, since the dissolved nitrogen concentration DN is feedback-controlled, the etching rate ER can be kept within a desired range. In FIG. 5, the dissolved nitrogen concentration DN of the chemical liquid 3 is a control amount, and the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time is an operation amount.
　図６は、一実施形態に係る基板処理方法の別の一部を示すフローチャートである。図６に示す工程Ｓ１３１～Ｓ１３２は、予め定められた時間毎に繰り返し行われる。図６に示す工程Ｓ１３１～Ｓ１３２は、図３に示す工程Ｓ１０１～Ｓ１０６と並行して行われてもよいし、図３に示す工程Ｓ１０１～Ｓ１０６の中断時に行われてもよい。 FIG. 6 is a flowchart showing another part of the substrate processing method according to the embodiment. Steps S131 to S132 shown in FIG. 6 are repeated at predetermined time intervals. The steps S131 to S132 shown in FIG. 6 may be performed in parallel with the steps S101 to S106 shown in FIG. 3, or may be performed when the steps S101 to S106 shown in FIG. 3 are interrupted.
　基板処理方法は、エッチングレートＥＲを測定する工程Ｓ１３１を有する。この工程Ｓ１３１では、エッチングレート測定部８０（図１参照）が、エッチングレートＥＲを測定する。エッチングレート測定部８０は、先ず、エッチング後のポリシリコン膜の膜厚を測定し、エッチング前後でのポリシリコン膜の膜厚差を算出する。次に、エッチングレート測定部８０は、算出した膜厚差をエッチング時間で除すことにより、エッチングレートＥＲを算出する。エッチングレート測定部８０は、その測定結果を示す信号を制御部９０に送信する。 The substrate processing method has a step S131 of measuring the etching rate ER. In this step S131, the etching rate measuring unit 80 (see FIG. 1) measures the etching rate ER. The etching rate measurement unit 80 first measures the film thickness of the polysilicon film after etching, and calculates the film thickness difference of the polysilicon film before and after etching. Next, the etching rate measurement unit 80 calculates the etching rate ER by dividing the calculated film thickness difference by the etching time. The etching rate measurement unit 80 transmits a signal indicating the measurement result to the control unit 90.
　基板処理方法は、測定したエッチングレートＥＲを基に、溶存窒素濃度ＤＮの設定値ＤＮ１、ＤＮ２を決める工程Ｓ１３２を有する。この工程Ｓ１３２は、制御部９０によって行われる。この工程Ｓ１３２の詳細については、後述する。 The substrate processing method has a step S132 of determining the set values DN1 and DN2 of the dissolved nitrogen concentration DN based on the measured etching rate ER. This step S132 is performed by the controller 90. Details of this step S132 will be described later.
　図７は、溶存窒素濃度の設定値を決定する工程の一例を示すフローチャートである。図７に示す工程Ｓ１４１～Ｓ１４５は、制御部９０によって実施される。なお、図７に示すフローチャートは、薬液３がＴＭＡＨ含有薬液である場合のものである。 FIG. 7 is a flowchart showing an example of a process of determining the set value of the dissolved nitrogen concentration. Steps S141 to S145 shown in FIG. 7 are performed by the control unit 90. The flowchart shown in FIG. 7 is for the case where the chemical liquid 3 is the TMAH-containing chemical liquid.
　薬液３の種類に関係なく、酸化に寄与しない溶存窒素の濃度ＤＮが小さいほど、酸化に寄与する全ての溶存ガスの合計濃度が大きい。従って、薬液３の種類に関係なく、酸化に寄与しない溶存窒素の濃度ＤＮが小さいほど、ポリシリコン膜の酸化が進みやすい。 Regardless of the type of chemical liquid 3, the smaller the concentration DN of dissolved nitrogen that does not contribute to oxidation, the greater the total concentration of all dissolved gases that contribute to oxidation. Therefore, regardless of the type of the chemical liquid 3, the smaller the concentration DN of the dissolved nitrogen that does not contribute to the oxidation, the easier the oxidation of the polysilicon film.
　薬液３がＴＭＡＨ含有薬液である場合、ポリシリコン膜の酸化が進むほど、エッチングレートＥＲが小さくなる。ＴＭＡＨ含有薬液は、酸化膜のエッチングが不得手だからである。 When the chemical liquid 3 is the TMAH-containing chemical liquid, the etching rate ER decreases as the oxidation of the polysilicon film progresses. This is because the TMAH-containing chemical solution is not good at etching the oxide film.
　従って、薬液３がＴＭＡＨ含有薬液である場合、酸化に寄与しない溶存窒素の濃度ＤＮが小さいほど、酸化に寄与する全ての溶存ガスの合計濃度が大きくなるので、エッチングレートＥＲが小さくなる。 Therefore, when the chemical solution 3 is a TMAH-containing chemical solution, the smaller the concentration DN of dissolved nitrogen that does not contribute to oxidation, the higher the total concentration of all dissolved gases that contribute to oxidation, and the smaller the etching rate ER.
　基板処理方法は、測定したエッチングレートＥＲが閾値ＥＲ１以上であるか否かを判定する工程Ｓ１４１を有する。閾値ＥＲ１は、下限値であって、単位時間当たりの基板２の処理枚数が設定枚数以上になるように決められる。 The substrate processing method has a step S141 of determining whether or not the measured etching rate ER is equal to or higher than a threshold value ER1. The threshold value ER1 is a lower limit value and is determined so that the number of processed substrates 2 per unit time is equal to or larger than the set number.
　測定したエッチングレートＥＲが閾値ＥＲ１よりも小さい場合（Ｓ１４１、ＮＯ）、制御部９０は溶存窒素濃度ＤＮの設定値ＤＮ１、ＤＮ２を大きくする（Ｓ１４２）。次回以降、溶存窒素濃度ＤＮを大きくできるので、エッチングレートＥＲを大きくでき、エッチングレートＥＲを閾値ＥＲ１以上に制御できる。その後、制御部９０は、今回の処理を終了する。 When the measured etching rate ER is smaller than the threshold value ER1 (S141, NO), the control unit 90 increases the set values DN1 and DN2 of the dissolved nitrogen concentration DN (S142). From the next time onward, since the dissolved nitrogen concentration DN can be increased, the etching rate ER can be increased, and the etching rate ER can be controlled to be equal to or higher than the threshold value ER1. After that, the control unit 90 ends this processing.
　一方、測定したエッチングレートＥＲが閾値ＥＲ１以上である場合（Ｓ１４１、ＹＥＳ）、制御部９０は測定したエッチングレートＥＲが閾値ＥＲ２以下であるか否かを判定する（Ｓ１４３）。閾値ＥＲ２は、上限値であって、閾値ＥＲ１と同じ値であるか、閾値ＥＲ１よりも大きい値である。閾値ＥＲ２は、意図しないダメージがエッチングによって発生しないように予め決められる。 On the other hand, if the measured etching rate ER is greater than or equal to the threshold ER1 (S141, YES), the control unit 90 determines whether the measured etching rate ER is less than or equal to the threshold ER2 (S143). The threshold value ER2 is an upper limit value and is the same value as the threshold value ER1 or a value larger than the threshold value ER1. The threshold value ER2 is predetermined so that unintentional damage does not occur due to etching.
　測定したエッチングレートＥＲが閾値ＥＲ２よりも大きい場合（Ｓ１４３、ＮＯ）、制御部９０は溶存窒素濃度ＤＮの設定値ＤＮ１、ＤＮ２を小さくする（Ｓ１４４）。次回以降、溶存窒素濃度ＤＮを小さくできるので、エッチングレートＥＲを小さくでき、エッチングレートＥＲを閾値ＥＲ２以下に制御できる。その後、制御部９０は、今回の処理を終了する。 When the measured etching rate ER is larger than the threshold value ER2 (S143, NO), the controller 90 reduces the set values DN1 and DN2 of the dissolved nitrogen concentration DN (S144). From the next time onward, since the dissolved nitrogen concentration DN can be reduced, the etching rate ER can be reduced, and the etching rate ER can be controlled to be equal to or lower than the threshold value ER2. After that, the control unit 90 ends this processing.
　一方、測定したエッチングレートＥＲが閾値ＥＲ２以下である場合（Ｓ１４３、ＹＥＳ）、制御部９０は溶存窒素濃度ＤＮの設定値ＤＮ１、ＤＮ２を維持する（Ｓ１４５）。次回以降、エッチングレートＥＲを同程度に維持できる。その後、制御部９０は、今回の処理を終了する。 On the other hand, when the measured etching rate ER is less than or equal to the threshold value ER2 (S143, YES), the control unit 90 maintains the set values DN1 and DN2 of the dissolved nitrogen concentration DN (S145). From the next time onward, the etching rate ER can be maintained at the same level. After that, the control unit 90 ends this processing.
　本実施形態によれば、エッチングレートＥＲをフィードバック制御するので、エッチングレートＥＲを所望の範囲内に収めることができる。図７では、エッチングレートＥＲが制御量であり、溶存窒素濃度ＤＮの設定値ＤＮ１、ＤＮ２が操作量である。 According to the present embodiment, since the etching rate ER is feedback-controlled, it is possible to keep the etching rate ER within a desired range. In FIG. 7, the etching rate ER is the controlled variable, and the set values DN1 and DN2 of the dissolved nitrogen concentration DN are the manipulated variables.
　なお、薬液３がＴＭＡＨ含有薬液である場合と、薬液３がアンモニア溶液またはコリン溶液である場合とでは、設定値ＤＮ１、ＤＮ２の操作が逆になる。薬液３がアンモニア溶液またはコリン溶液である場合、薬液３がＴＭＡＨ含有薬液とは異なり、ポリシリコン膜の酸化が進むほど、エッチングレートＥＲが大きくなるからである。 Note that the operation of the set values DN1 and DN2 is reversed when the chemical liquid 3 is the TMAH-containing chemical liquid and when the chemical liquid 3 is the ammonia solution or the choline solution. This is because when the chemical liquid 3 is an ammonia solution or a choline solution, the chemical liquid 3 is different from the TMAH-containing chemical liquid, and the etching rate ER increases as the oxidation of the polysilicon film progresses.
　ここで、薬液３がアンモニア溶液またはコリン溶液である場合に溶存窒素濃度ＤＮの設定値ＤＮ１、ＤＮ２を決定する工程について、図７との相違点を主に説明する。先ず、測定したエッチングレートＥＲが閾値ＥＲ１よりも小さい場合（Ｓ１４１、ＮＯ）、制御部９０は、溶存窒素濃度ＤＮの設定値ＤＮ１、ＤＮ２を、大きくする（Ｓ１４２）のではなく、小さくする（Ｓ１４４）。また、測定したエッチングレートＥＲが閾値ＥＲ２よりも大きい場合（Ｓ１４３、ＮＯ）、制御部９０は、溶存窒素濃度ＤＮの設定値ＤＮ１、ＤＮ２を、小さくする（Ｓ１４４）のではなく、大きくする（Ｓ１４２）。これにより、エッチングレートＥＲを所望の範囲内に収めることができる。 Here, the process of determining the set values DN1 and DN2 of the dissolved nitrogen concentration DN when the chemical liquid 3 is an ammonia solution or a choline solution will be described mainly with respect to the difference from FIG. 7. First, when the measured etching rate ER is smaller than the threshold value ER1 (S141, NO), the controller 90 decreases the set values DN1 and DN2 of the dissolved nitrogen concentration DN instead of increasing them (S142) (S144). ). When the measured etching rate ER is larger than the threshold value ER2 (S143, NO), the control unit 90 increases the set values DN1 and DN2 of the dissolved nitrogen concentration DN instead of decreasing them (S144) (S142). ). Thereby, the etching rate ER can be kept within a desired range.
　以上、本開示に係る基板処理装置および基板処理方法の実施形態について説明したが、本開示は上記実施形態などに限定されない。特許請求の範囲に記載された範疇内において、各種の変更、修正、置換、付加、削除、および組合わせが可能である。それらについても当然に本開示の技術的範囲に属する。 Although the embodiments of the substrate processing apparatus and the substrate processing method according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments and the like. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. Naturally, those are also within the technical scope of the present disclosure.
　図９は、図１に示す貯留部用溶解ユニットの変形例を示す図である。図９に示すように、貯留部用溶解ユニット６１は、パージ配管６２を含んでもよい。パージ配管６２は、貯留部３０の上部空間に窒素ガスを吐出する。貯留部３０の上部空間は、薬液３の液面よりも上方の空間である。パージ配管６２の途中には、流量調整弁７２が配置される。窒素ガスの流量が多いほど、単位時間当たりに薬液３に溶解させる窒素ガスの量が増え、薬液３の溶存窒素濃度ＤＮが大きくなる。 FIG. 9 is a diagram showing a modification of the storage unit dissolution unit shown in FIG. 1. As shown in FIG. 9, the storage unit dissolution unit 61 may include a purge pipe 62. The purge pipe 62 discharges nitrogen gas into the upper space of the storage section 30. The upper space of the reservoir 30 is a space above the liquid surface of the chemical liquid 3. A flow rate adjusting valve 72 is arranged in the middle of the purge pipe 62. As the flow rate of nitrogen gas increases, the amount of nitrogen gas dissolved in the chemical liquid 3 per unit time increases, and the dissolved nitrogen concentration DN of the chemical liquid 3 increases.
　貯留部用溶解ユニット６１は、排液ライン８１を含んでもよい。排液ライン８１は、例えば、貯留部３０に貯留された薬液３の液面の高さが設定値に達すると、貯留部３０から薬液３を排出する。排液ライン８１の一端は、例えばパージ配管６２の途中に結合される。パージ配管６２の一端は、例えば貯留部３０の天井にて開口する。貯留部３０が薬液３で満たされると、薬液３が貯留部３０から排液ライン８１に排出される。 The storage unit dissolution unit 61 may include a drainage line 81. The liquid drain line 81 discharges the chemical liquid 3 from the storage unit 30 when the height of the liquid surface of the chemical liquid 3 stored in the storage unit 30 reaches a set value, for example. One end of the drainage line 81 is joined, for example, in the middle of the purge pipe 62. One end of the purge pipe 62 opens at the ceiling of the storage unit 30, for example. When the storage portion 30 is filled with the chemical liquid 3, the chemical liquid 3 is discharged from the storage portion 30 to the drain line 81.
　なお、パージ配管６２の一端は、図９では貯留部３０の天井にて開口するが、貯留部３０の天井から下方に突出していてもよい。この場合、貯留部３０が薬液３で満たされる前に、薬液３の液面の高さがパージ配管６２の一端まで上昇すると、薬液３が貯留部３０から排液ライン８１に排出される。また、パージ配管６２の一端は、貯留部３０の側壁の上部にて開口してもよいし、貯留部３０の側壁の上部から内側に突出してもよい。 Note that one end of the purge pipe 62 is open at the ceiling of the storage part 30 in FIG. 9, but may be projected downward from the ceiling of the storage part 30. In this case, if the height of the liquid surface of the chemical liquid 3 rises to one end of the purge pipe 62 before the storage portion 30 is filled with the chemical liquid 3, the chemical liquid 3 is discharged from the storage portion 30 to the drain line 81. Further, one end of the purge pipe 62 may be opened at the upper portion of the side wall of the storage section 30 or may be protruded inward from the upper side of the side wall of the storage section 30.
　なお、排液ライン８１の一端は、図９では窒素ガス用のパージ配管６２の途中に結合されるが、結合されてなくてもよい。排液ライン８１は、パージ配管６２とは別に設けられてもよい。例えば、酸素ガス用のバブリング配管６３の代わりに、酸素ガス用のパージ配管が設けられ、そのパージ配管の途中に排液ライン８１の一端が結合されてもよい。 Note that, although one end of the drainage line 81 is connected in the middle of the purge pipe 62 for nitrogen gas in FIG. 9, it may not be connected. The drainage line 81 may be provided separately from the purge pipe 62. For example, instead of the bubbling pipe 63 for oxygen gas, a purge pipe for oxygen gas may be provided, and one end of the drainage line 81 may be joined in the middle of the purge pipe.
　排液ライン８１の途中には、開閉弁８２が設けられる。貯留部３０の内部には、液面レベルセンサ８３が設けられる。液面レベルセンサ８３は、薬液３の液面の高さが設定値に達したか否かを検出する。液面レベルセンサ８３の検出結果に応じて、開閉弁８２が排液ライン８１の流路を開閉する。 An opening/closing valve 82 is provided in the middle of the drainage line 81. A liquid level sensor 83 is provided inside the storage unit 30. The liquid surface level sensor 83 detects whether or not the height of the liquid surface of the chemical liquid 3 has reached a set value. The on-off valve 82 opens and closes the flow path of the drainage line 81 according to the detection result of the liquid level sensor 83.
　液面レベルセンサ８３が薬液３の液面の高さが設定値に達したことを検出すると、開閉弁８２が排液ライン８１の流路を開放する。その結果、薬液３が貯留部３０から排液ライン８１に排出される。 When the liquid level sensor 83 detects that the liquid level of the chemical liquid 3 has reached the set value, the open/close valve 82 opens the flow path of the drain line 81. As a result, the chemical liquid 3 is discharged from the reservoir 30 to the drain line 81.
　一方、液面レベルセンサ８３が薬液３の液面の高さが設定値に達していないことを検出すると、開閉弁８２が排液ライン８１の流路を閉塞する。貯留部３０の上部空間の気圧が大気圧よりも低い負圧になるのを抑制でき、貯留部３０の内部にて薬液３が揮発してしまうのを抑制できる。排液ライン８１による薬液３の排出先は、負圧であってもよい。この場合に、開閉弁８２が無いと、貯留部３０の上部空間の気圧が負圧になりやすい。 On the other hand, when the liquid level sensor 83 detects that the liquid level of the chemical liquid 3 has not reached the set value, the open/close valve 82 closes the flow path of the drain line 81. It is possible to prevent the atmospheric pressure in the upper space of the storage unit 30 from becoming a negative pressure lower than the atmospheric pressure, and to prevent the chemical liquid 3 from volatilizing inside the storage unit 30. The discharge destination of the chemical liquid 3 through the drain line 81 may be negative pressure. In this case, if the opening/closing valve 82 is not provided, the atmospheric pressure in the upper space of the storage section 30 is likely to be negative.
　また、貯留部用溶解ユニット６１は、排気ライン８４を含んでもよい。排気ライン８４は、貯留部３０の上部空間の気圧が大気圧よりも高い正圧になるのを抑制すべく、貯留部３０の上部空間に溜まったガスを外部に放出する。排気ライン８４の一端は、例えばパージ配管６２の途中に結合される。排気ライン８４に薬液３が流れ込まないように、排気ライン８４は排液ライン８１よりも貯留部３０から遠い地点でパージ配管６２に結合される。 Further, the storage unit dissolution unit 61 may include an exhaust line 84. The exhaust line 84 releases the gas accumulated in the upper space of the storage unit 30 to the outside in order to suppress the atmospheric pressure of the upper space of the storage unit 30 from becoming a positive pressure higher than the atmospheric pressure. One end of the exhaust line 84 is joined, for example, in the middle of the purge pipe 62. The exhaust line 84 is connected to the purge pipe 62 at a point farther from the storage section 30 than the drainage line 81 so that the chemical liquid 3 does not flow into the exhaust line 84.
　本出願は、２０１９年１月１０日に日本国特許庁に出願した特願２０１９－００２９４９号に基づく優先権を主張するものであり、特願２０１９－００２９４９号の全内容を本出願に援用する。 This application claims priority based on Japanese Patent Application No. 2019-002949 filed with the Japan Patent Office on January 10, 2019, and the entire contents of Japanese Patent Application No. 2019-002949 are incorporated into the present application. ..
１　　基板処理装置
２　　基板
３　　薬液
１０　処理部
１１　処理容器
３０　貯留部
３１　供給ライン
４１　回収ライン
５０　測定部
５１　溶存窒素濃度計
６０　溶解部
６１　貯留部用溶解ユニット
６２　バブリング配管
６４Ａ　回収ライン用溶解ユニット
６４Ｂ　回収ライン用溶解ユニット
６７　処理部用溶解ユニット
９０　制御部 DESCRIPTION OF SYMBOLS 1 Substrate processing apparatus 2 Substrate 3 Chemical solution 10 Processing part 11 Processing container 30 Storage part 31 Supply line 41 Recovery line 50 Measuring part 51 Dissolved nitrogen concentration meter 60 Dissolution part 61 Storage part dissolution unit 62 Bubbling piping 64A Recovery line dissolution unit 64B Dissolution unit 67 for recovery line Dissolution unit 90 for processing unit Control unit

Claims (17)

  1. 　基板に形成されたポリシリコン膜またはアモルファスシリコン膜を、窒素ガスを予め溶解させたアルカリ性の薬液でエッチングする処理部と、
    　前記薬液の溶存窒素濃度を測定する測定部と、
    　前記薬液に窒素ガスを溶解させる溶解部と、
    　前記測定部によって測定した溶存窒素濃度を基に、前記溶解部によって単位時間当たりに前記薬液に溶解させる窒素ガスの量を決める制御部とを備える、基板処理装置。     A processing unit for etching the polysilicon film or the amorphous silicon film formed on the substrate with an alkaline chemical solution in which nitrogen gas is previously dissolved,
    A measuring unit for measuring the dissolved nitrogen concentration of the chemical solution,
    A dissolving portion for dissolving nitrogen gas in the chemical solution,
    A substrate processing apparatus comprising: a control unit that determines the amount of nitrogen gas dissolved in the chemical solution per unit time by the dissolution unit based on the dissolved nitrogen concentration measured by the measurement unit.
  2. 　前記薬液を貯留する貯留部と、
    　前記貯留部から前記処理部に前記薬液を供給する供給ラインとを備える、請求項１に記載の基板処理装置。     A storage part for storing the chemical liquid,
    The substrate processing apparatus according to claim 1, further comprising: a supply line that supplies the chemical liquid from the storage unit to the processing unit.
  3. 　前記溶解部は、前記貯留部に窒素ガスを供給することにより、前記薬液に窒素ガスを溶解させる貯留部用溶解ユニットを有する、請求項２に記載の基板処理装置。 The substrate processing apparatus according to claim 2, wherein the dissolution unit has a storage unit dissolution unit that dissolves the nitrogen gas in the chemical liquid by supplying nitrogen gas to the storage unit.
  4. 　前記貯留部用溶解ユニットは、前記貯留部に貯留されている前記薬液の内部に窒素ガスを吐出するバブリング配管を含む、請求項３に記載の基板処理装置。 The substrate processing apparatus according to claim 3, wherein the storage unit dissolution unit includes a bubbling pipe that discharges nitrogen gas into the chemical liquid stored in the storage unit.
  5. 　前記処理部から前記貯留部に前記薬液を戻す回収ラインを備え、
    　前記溶解部は、前記回収ラインの途中に、前記薬液に窒素ガスを溶解させる回収ライン用溶解ユニットを有する、請求項２～４のいずれか１項に記載の基板処理装置。     A recovery line for returning the chemical liquid from the processing unit to the storage unit is provided,
    The substrate processing apparatus according to any one of claims 2 to 4, wherein the dissolution unit has a recovery line dissolution unit that dissolves nitrogen gas in the chemical solution in the middle of the recovery line.
  6. 　前記測定部は、前記供給ラインの途中に、前記供給ラインを流れる前記薬液の溶存窒素濃度を測定する溶存窒素濃度計を有する、請求項２～５のいずれか１項に記載の基板処理装置。 The substrate processing apparatus according to any one of claims 2 to 5, wherein the measuring unit has, in the middle of the supply line, a dissolved nitrogen concentration meter that measures a dissolved nitrogen concentration of the chemical liquid flowing through the supply line.
  7. 　前記処理部は、前記基板を収容する処理容器を有し、
    　前記溶解部は、前記処理容器の内部に窒素ガスを供給することにより、前記薬液に窒素ガスを溶解させる処理部用溶解ユニットを有する、請求項１～６のいずれか１項に記載の基板処理装置。     The processing unit has a processing container that accommodates the substrate,
    The substrate processing according to any one of claims 1 to 6, wherein the dissolution unit has a processing unit dissolution unit that dissolves nitrogen gas into the chemical liquid by supplying nitrogen gas into the processing container. apparatus.
  8. 　前記制御部は、
    　測定した溶存窒素濃度が設定値よりも小さい場合に、前記溶解部によって単位時間当たりに前記薬液に溶解させる窒素ガスの量を増やし、
    　測定した溶存窒素濃度が設定値よりも大きい場合に、前記溶解部によって前記薬液に溶解させる窒素ガスの量を減らす、請求項１～７のいずれか１項に記載の基板処理装置。     The control unit is
    When the measured dissolved nitrogen concentration is lower than the set value, the amount of nitrogen gas dissolved in the chemical solution per unit time by the dissolving unit is increased,
    The substrate processing apparatus according to claim 1, wherein when the measured dissolved nitrogen concentration is higher than a set value, the amount of nitrogen gas dissolved in the chemical liquid by the dissolving unit is reduced.
  9. 　前記薬液はＴＭＡＨ（水酸化テトラメチルアンモニウム）を含み、
    　前記薬液のエッチングレートを測定するエッチングレート測定部を備え、
    　前記制御部は、
    　測定した前記エッチングレートが閾値よりも小さい場合に、溶存窒素濃度の設定値を大きくし、
    　測定した前記エッチングレートが閾値よりも大きい場合に、溶存窒素濃度の設定値を小さくする、請求項１～８のいずれか１項に記載の基板処理装置。     The chemical solution contains TMAH (tetramethylammonium hydroxide),
    An etching rate measuring unit for measuring the etching rate of the chemical solution is provided,
    The control unit is
    When the measured etching rate is smaller than the threshold value, increase the set value of the dissolved nitrogen concentration,
    9. The substrate processing apparatus according to claim 1, wherein the set value of the dissolved nitrogen concentration is reduced when the measured etching rate is higher than a threshold value.
  10. 　基板に形成されたポリシリコン膜またはアモルファスシリコン膜を、窒素ガスを予め溶解させたアルカリ性の薬液でエッチングする工程と、
    　前記薬液の溶存窒素濃度を測定する工程と、
    　測定した溶存窒素濃度を基に、単位時間当たりに前記薬液に溶解させる窒素ガスの量を決める工程と、
    　決めた量の窒素ガスを前記薬液に溶解させる工程とを有する、基板処理方法。     A step of etching the polysilicon film or the amorphous silicon film formed on the substrate with an alkaline chemical solution in which nitrogen gas is previously dissolved,
    A step of measuring the dissolved nitrogen concentration of the chemical solution,
    Based on the measured dissolved nitrogen concentration, a step of determining the amount of nitrogen gas dissolved in the chemical solution per unit time,
    And a step of dissolving a predetermined amount of nitrogen gas in the chemical solution.
  11. 　前記薬液を貯留部に貯留する工程と、
    　前記薬液を前記貯留部から、前記基板の前記薬液によるエッチングが行われる処理部に供給する工程とを有する、請求項１０に記載の基板処理方法。     A step of storing the drug solution in a storage part,
    The substrate processing method according to claim 10, further comprising: supplying the chemical solution from the storage section to a processing section in which the substrate is etched by the chemical solution.
  12. 　前記貯留部に貯留されている前記薬液の内部で窒素ガスを吐出することにより、前記薬液の内部に窒素ガスの気泡を発生させる工程を含む、請求項１１に記載の基板処理方法。 The substrate processing method according to claim 11, comprising a step of generating nitrogen gas bubbles inside the chemical liquid by discharging nitrogen gas inside the chemical liquid stored in the storage section.
  13. 　前記処理部から前記貯留部まで延びる回収ラインによって、前記薬液を前記処理部から前記貯留部に戻す工程を有し、
    　前記薬液に窒素ガスを溶解させる工程は、前記回収ラインの途中で、前記薬液に窒素ガスを溶解させる工程を有する、請求項１１または１２に記載の基板処理方法。     A recovery line extending from the processing unit to the storage unit, including a step of returning the chemical liquid from the processing unit to the storage unit,
    The substrate processing method according to claim 11 or 12, wherein the step of dissolving nitrogen gas in the chemical liquid has a step of dissolving nitrogen gas in the chemical liquid in the middle of the recovery line.
  14. 　前記薬液の溶存窒素濃度を測定する工程は、前記貯留部から前記処理部に前記薬液を供給する供給ラインの途中に配置される溶存窒素濃度計で、前記供給ラインを流れる前記薬液の溶存窒素濃度を測定する工程を含む、請求項１１～１３のいずれか１項に記載の基板処理方法。 The step of measuring the dissolved nitrogen concentration of the chemical liquid is a dissolved nitrogen concentration meter arranged in the middle of a supply line for supplying the chemical liquid from the storage unit to the processing unit, and the dissolved nitrogen concentration of the chemical liquid flowing through the supply line. The substrate processing method according to claim 11, further comprising the step of measuring
  15. 　前記エッチングする工程は、処理容器の内部に収容された前記基板に向けて、前記薬液を吐出する工程を含み、
    　前記薬液に窒素ガスを溶解させる工程は、前記処理容器の内部に窒素ガスを供給することにより、前記薬液に窒素ガスを溶解させる工程を含む、請求項１０～１４のいずれか１項に記載の基板処理方法。     The etching step includes a step of discharging the chemical solution toward the substrate housed inside a processing container,
    15. The step of dissolving nitrogen gas in the chemical liquid includes the step of dissolving nitrogen gas in the chemical liquid by supplying nitrogen gas to the inside of the processing container. Substrate processing method.
  16. 　単位時間当たりに前記薬液に溶解させる窒素ガスの量を決める工程は、
    　測定した溶存窒素濃度が設定値よりも小さい場合に、単位時間当たりに前記薬液に溶解させる窒素ガスの量を増やす工程と、
    　測定した溶存窒素濃度が設定値よりも大きい場合に、単位時間当たりに前記薬液に溶解させる窒素ガスの量を減らす工程とを有する、請求項１０～１５のいずれか１項に記載の基板処理方法。     The step of determining the amount of nitrogen gas dissolved in the chemical solution per unit time is
    When the measured dissolved nitrogen concentration is lower than the set value, a step of increasing the amount of nitrogen gas dissolved in the chemical solution per unit time,
    The substrate processing method according to any one of claims 10 to 15, further comprising a step of reducing the amount of nitrogen gas dissolved in the chemical solution per unit time when the measured dissolved nitrogen concentration is higher than a set value. ..
  17. 　前記薬液はＴＭＡＨ（水酸化テトラメチルアンモニウム）を含み、
    　ポリシリコン膜またはアモルファスシリコン膜の前記薬液によるエッチングレートを測定する工程と、
    　測定した前記エッチングレートが閾値よりも小さい場合に、溶存窒素濃度の設定値を大きくする工程と、
    　測定した前記エッチングレートが閾値よりも大きい場合に、溶存窒素濃度の設定値を小さくする工程とを有する、請求項１０～１６のいずれか１項に記載の基板処理方法。     The chemical solution contains TMAH (tetramethylammonium hydroxide),
    Measuring the etching rate of the polysilicon film or the amorphous silicon film by the chemical solution,
    When the measured etching rate is smaller than the threshold value, a step of increasing the set value of the dissolved nitrogen concentration,
    The substrate processing method according to any one of claims 10 to 16, further comprising a step of reducing a set value of the dissolved nitrogen concentration when the measured etching rate is higher than a threshold value.
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