WO2014046229A1 - Cleaning method and cleaning device - Google Patents

Cleaning method and cleaning device Download PDF

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Publication number
WO2014046229A1
WO2014046229A1 PCT/JP2013/075428 JP2013075428W WO2014046229A1 WO 2014046229 A1 WO2014046229 A1 WO 2014046229A1 JP 2013075428 W JP2013075428 W JP 2013075428W WO 2014046229 A1 WO2014046229 A1 WO 2014046229A1
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Prior art keywords
cleaning
sulfuric acid
acid solution
electrolytic
liquid
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PCT/JP2013/075428
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French (fr)
Japanese (ja)
Inventor
融 正岡
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栗田工業株式会社
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Publication of WO2014046229A1 publication Critical patent/WO2014046229A1/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
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67017—Apparatus for fluid treatment
    • H01L21/67028—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
    • H01L21/6704—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing
    • H01L21/67057—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing with the semiconductor substrates being dipped in baths or vessels
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/26—Processing photosensitive materials; Apparatus therefor
    • G03F7/42—Stripping or agents therefor
    • 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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System 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
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3105—After-treatment
    • H01L21/311—Etching the insulating layers by chemical or physical means
    • H01L21/31127—Etching organic layers
    • H01L21/31133—Etching organic layers by chemical means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
    • B08B3/04—Cleaning involving contact with liquid
    • B08B3/10—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
    • B08B3/12—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration by sonic or ultrasonic vibrations

Definitions

  • the present invention relates to a cleaning method and a cleaning apparatus that use an electrolyzed sulfuric acid solution as a cleaning liquid.
  • the process of manufacturing a semiconductor, a liquid crystal substrate, or the like includes a resist stripping process that removes a resist applied as a protective film in a dose implantation process or a dry etching process. Since the resist is an organic substance, it is generally removed by an organic solvent or sulfuric acid / hydrogen peroxide (SPM). However, under the conditions of high dose implantation and high-speed dry etching, the resist is cured by high-energy ion implantation, and peeling with a conventional organic solvent or SPM becomes difficult. A part of the cured resist is graphitized and is fixed to the material surface. An improved method using SPM has been proposed with the intention of peeling such a cured resist (Patent Document 1). That is, Patent Document 1 discloses a cleaning method in which SPM to which ultrasonic vibration is applied is supplied to the surface of the substrate, and the cured layer is peeled off while being destroyed by the physical energy of ultrasonic vibration.
  • SPM sulfuric acid / hydrogen peroxide
  • SPM is a mixed liquid of sulfuric acid and hydrogen peroxide, and contains caroic acid generated by the following reaction.
  • the mechanism by which the cleaning effect is lost by foaming is as follows. Due to the generation of bubbles, the cleaning effect is lost by the following two mechanisms. (1) Since the ultrasonic wave propagates in a straight flow, if there are fine bubbles, the straight travel is blocked and the cleaning effect is lost. (2) SPM in the O 2 gas generated O 2 is supersaturated. One of the ultrasonic cleaning effects is cavitation (energy generation due to generation and disappearance of vacuum bubbles), but if dissolved gas is present, the gas enters the cavitation and the effect is lost. If the cavitation effect is lost, the resist stripping effect due to the activation of caloic acid and cavitation cannot be exhibited, and cleaning cannot be performed.
  • the present invention has been made against the background of the above circumstances, and a cleaning method capable of sufficiently exerting an ultrasonic cleaning effect by using ultrasonic waves in combination with an electrolytic sulfuric acid solution generated by electrolyzing a sulfuric acid solution. And it aims at providing a washing device.
  • the first present invention provides ultrasonic waves to an electrolytic sulfuric acid solution generated by electrolyzing a sulfuric acid solution, and the electrolytic sulfuric acid solution to which the ultrasonic waves are applied is used to clean the material to be cleaned. Surface cleaning is performed.
  • the cleaning method of the second aspect of the present invention is characterized in that, in the first aspect of the present invention, the temperature of the electrolytic sulfuric acid solution used for the cleaning is 40 ° C. or higher.
  • the cleaning method of the third aspect of the present invention is characterized in that, in the first or second aspect of the present invention, the temperature of the electrolytic sulfuric acid solution used for the cleaning is 95 ° C. or less.
  • the cleaning method of the fourth aspect of the present invention is characterized in that, in any of the first to third aspects of the present invention, the frequency of the ultrasonic wave is 20 kHz to 5 MHz.
  • the cleaning method of the fifth aspect of the present invention is characterized in that, in any of the first to fourth aspects of the present invention, the material to be cleaned is an electronic material to which a resist is attached.
  • the cleaning method of the sixth aspect of the present invention is characterized in that in any one of the first to fifth aspects of the present invention, the electrolytic sulfuric acid solution is subjected to gas-liquid separation before applying ultrasonic waves to the electrolytic sulfuric acid solution. .
  • the electrolytic sulfuric acid solution is degassed before applying ultrasonic waves to the electrolytic sulfuric acid solution. It is characterized by.
  • the cleaning device of the eighth aspect of the present invention includes an electrolytic device for electrolyzing a sulfuric acid solution, A cleaning section for cleaning the material to be cleaned using an electrolytic sulfuric acid solution generated by electrolysis in the electrolysis apparatus as a cleaning liquid; A cleaning liquid supply line for supplying an electrolytic sulfuric acid solution electrolyzed by the electrolytic device to the cleaning unit; And an ultrasonic application device that applies ultrasonic waves to the electrolytic sulfuric acid solution used in the cleaning section.
  • the cleaning apparatus according to a ninth aspect of the present invention is the cleaning apparatus according to the eighth aspect, further comprising a gas-liquid separation unit that performs gas-liquid separation of the electrolytic sulfuric acid solution before applying the ultrasonic wave.
  • a cleaning apparatus is the cleaning apparatus according to the ninth aspect, further comprising a deaeration unit that degass the electrolytic sulfuric acid solution before the ultrasonic wave application after the gas-liquid separation unit.
  • the eleventh aspect of the present invention is the cleaning apparatus according to any one of the eighth to tenth aspects of the present invention, further comprising a heating unit for heating the electrolytic sulfuric acid solution used in the cleaning unit.
  • the cleaning apparatus of the twelfth aspect of the present invention is the batch type according to any one of the eighth to eleventh aspects of the present invention, wherein the cleaning section immerses and cleans one or two or more materials to be cleaned in a cleaning liquid in a cleaning tank. And the ultrasonic wave imparting device propagates ultrasonic waves to the cleaning tank.
  • a cleaning apparatus is the cleaning apparatus according to any one of the eighth to eleventh aspects, wherein the cleaning section contacts and cleans one or more materials to be cleaned while feeding the cleaning liquid.
  • the ultrasonic applicator propagates the ultrasonic wave to the material to be cleaned in a nozzle that feeds the cleaning liquid toward the material to be cleaned.
  • an electrolytic sulfuric acid solution obtained by electrolyzing a sulfuric acid solution is used as a cleaning liquid.
  • the electrolytic sulfuric acid solution has an extremely low amount of bubbles generated when ultrasonic waves are used, although the reason is not clear. For this reason, even if ultrasonic waves are used in combination, it is considered that the straight flow / cavitation effect is not reduced by bubbles and a sufficient cleaning effect can be exhibited.
  • the electrolytic sulfuric acid solution contains an oxidizing agent such as peroxodisulfuric acid, the organic contaminant removal effect is higher than that of the sulfuric acid solution.
  • the electrode material for electrolyzing the sulfuric acid solution is not particularly limited, but a material having a high oxygen generation overvoltage is preferable, and a diamond electrode doped with a conductive substance such as boron is more preferable.
  • the diamond electrode is preferably provided at a site in contact with the sulfuric acid solution, and particularly preferably used for the anode. Similarly, a diamond electrode can be used for the cathode.
  • the concentration of the sulfuric acid solution to be electrolyzed is not particularly limited. When used for pickling stainless steel, etc., dilute sulfuric acid (20% or less by mass) is preferable. When used for removing a cured resist, 75 to 96% by mass is used because of the permeation power of sulfuric acid into the resist. More preferably, it is 80 to 92%.
  • the current density during electrolysis is preferably 10 to 10,000 A / m 2 with respect to the electrode area, and the sulfuric acid solution is applied in the direction parallel to the electrode surface to 1 to 10,000 m / hr. It is preferable to carry out the contact treatment while passing the liquid at a linear velocity.
  • the liquid temperature during electrolysis is preferably 10 to 90 ° C. in order to prevent electrolysis efficiency and self-decomposition of the oxidizing agent in the electrolytic solution.
  • the pretreatment method of the electrolytic sulfuric acid solution is not particularly limited, but oxygen gas or hydrogen gas is generated on the electrode surface during electrolysis and mixed with the liquid, so that it is preliminarily gas-liquid separated and then degassed before applying ultrasonic waves.
  • oxygen gas or hydrogen gas is generated on the electrode surface during electrolysis and mixed with the liquid, so that it is preliminarily gas-liquid separated and then degassed before applying ultrasonic waves.
  • gas-liquid separation one using power or centrifugal force or one using a permeable membrane can be used, but the invention is not limited to this, and the electrolytic solution can be used by separating the electrolytic solution and the electrolytic gas. If it is.
  • a degassing membrane or an aspirator can be used for degassing.
  • the deaeration time is preferably 5 to 10 minutes.
  • the frequency of the ultrasonic wave applied to the electrolytic sulfuric acid solution is 20 kHz or more and 5 MHz or less. It is desirable that the electrolytic sulfuric acid solution used for cleaning by applying ultrasonic waves has a liquid temperature of 40 ° C. or higher. If it is less than 40 degreeC, the oxidizing agent in electrolyte solution will be hard to activate.
  • the liquid temperature is desirably 95 ° C. or lower. If the liquid temperature exceeds 95 ° C., it is necessary to change the material and the solvent for propagating ultrasonic waves to those having a high boiling point such as silicon oil. In addition, when the temperature is high, the self-decomposition tends to proceed early.
  • the action of cavitation by ultrasonic waves and the action of persulfuric acid can be sufficiently obtained, and a high cleaning action can be obtained.
  • a high cleaning action can be obtained.
  • even in a resist cured with a semiconductor material there is an effect of effective peeling. .
  • the cleaning device 1 includes an electrolysis device 10 and a cleaning unit 20.
  • the electrolyzer 10 is a non-diaphragm type, and an anode 11a and a cathode 11b each having at least a portion in contact with a sulfuric acid solution as a diamond electrode are arranged inside without being separated by a diaphragm, and a DC power source (not shown) is connected to both electrodes. ing.
  • the electrolysis apparatus may be configured as a diaphragm type, or may be a non-diaphragm type in which a bipolar electrode is disposed between the anode 11a and the cathode 11b.
  • An electrolytic solution storage tank 15 is connected to the electrolyzer 10 through an electrolytic side circulation line 12 so as to be circulated.
  • a circulation pump 13 for circulating the sulfuric acid solution and a cooler 14 are provided in this order on the electrolytic side circulation line 12 on the feed side from the electrolytic solution storage tank 15 toward the electrolytic device 10.
  • a gas-liquid separator 16 is interposed in the return-side electrolysis-side circulation line 12 from the electrolyzer 10 toward the electrolyte storage tank 15.
  • the gas-liquid separator 16 corresponds to a gas-liquid separator.
  • the gas-liquid separator 16 can be configured by using gravity or centrifugal force, but the present invention is not limited to a specific configuration.
  • a liquid feed line 22 is connected to the electrolytic solution storage tank 15 via a liquid feed pump 23.
  • the liquid feed line 22 corresponds to a cleaning liquid supply line.
  • a degassing device 24 is provided in the liquid feed line 22 on the downstream side of the liquid feed pump 23.
  • the deaeration device 24 corresponds to a deaeration unit.
  • the deaeration device 24 can be constituted by a deaeration membrane or an aspirator, but the present invention is not limited to a specific configuration.
  • the liquid feed front end side of the liquid feed line 22 is connected to the cleaning tank 21 of the batch type cleaning unit 20.
  • the cleaning tank 21 is provided with a heater 25 for heating the stored cleaning liquid. For example, the cleaning liquid is heated to a liquid temperature of 40 to 95 ° C.
  • the cleaning tank 21 is housed in the outer tank 31 as an inner tank, and between the inner and outer tanks, silicon oil or the like is filled as the propagation liquid 33.
  • the type of the propagating liquid is not particularly limited, but it is desirable that the propagating liquid has high heat resistance with respect to the temperature of the cleaning liquid and can transmit ultrasonic waves efficiently.
  • An ultrasonic transducer 32 is attached to the outer wall of the outer tub 31.
  • An ultrasonic applicator 30 is configured by the ultrasonic transducer 32, the outer tank 31, and the propagation liquid 33.
  • the ultrasonic wave applying device may be configured by directly attaching the ultrasonic vibrator to the cleaning tank 21.
  • the ultrasonic transducer 32 one that generates ultrasonic waves having a frequency of 20 kHz or more and 5 MHz or less is used.
  • a drain line 26 is connected to the cleaning tank 21.
  • a cooler 27 is interposed in the drainage line 26 to cool the cleaning liquid flowing through the drainage line 26 to an appropriate temperature.
  • the front end side of the drainage line 26 is connected to the electrolyte storage tank 15.
  • the semiconductor material 100 subjected to high dose implantation is used as the cleaning target material.
  • an electronic material or the like to which a resist is attached can be used as a material to be cleaned.
  • the electrolytic solution storage tank 15 a sulfuric acid solution having a sulfuric acid concentration of 75 to 96% by mass (preferably 80 to 92% by mass) is stored.
  • the sulfuric acid solution is fed through the electrolysis-side circulation line 12 by the circulation pump 13, cooled by the cooler 14 (temperature in the electrolysis apparatus 10) to 10 to 90 ° C., and then enters the electrolysis apparatus 10. Introduced on the side.
  • a DC power source is energized between the anode 11a and the cathode 11b so that the current density is 10 to 10,000 A / m 2 with respect to the electrode area, and the sulfuric acid solution introduced into the electrolyzer 10 is the electrode surface. 1 to 10,000 m / hr. Electrolysis is performed while passing the liquid at a linear speed of. The linear speed can be adjusted by the feed amount of the circulation pump 13. In the electrolysis apparatus 10, an oxidizing substance containing persulfuric acid is generated on the anode 11a side by electrolysis.
  • the oxidizing substance is sent to the outside of the electrolysis apparatus 10 in a state of being mixed with the sulfuric acid solution, separated into gas and liquid by the gas / liquid separator 16, and then returned to the electrolyte storage tank 15 through the electrolysis side circulation line 12. .
  • the sulfuric acid solution contains persulfuric acid, is returned to the electrolytic solution storage tank 15 through the electrolytic side circulation line 12, and then repeatedly sent to the electrolyzer 10, where the concentration of persulfuric acid is increased by electrolysis.
  • the persulfuric acid concentration include 2 to 20 g as S 2 O 8 2 ⁇ / L in units of peroxodisulfuric acid.
  • the persulfuric acid concentration becomes moderate, a part of the sulfuric acid solution in the electrolytic solution storage tank 15 is fed through the liquid feeding line 22 by the liquid feeding pump 23.
  • the sulfuric acid solution flowing through the liquid feed line 22 is deaerated by the deaerator 24, then sent to the washing tank 21, and heated to an appropriate temperature (40 ° C. to 90 ° C.) by the heater 25. If the electrolytic sulfuric acid solution to be fed has the appropriate liquid temperature, heating by the heater 25 is not necessarily required.
  • ultrasonic waves of 20 kHz or more and 5 MHz or less are applied by the ultrasonic wave applying device 30.
  • the ultrasonic wave is transmitted to the cleaning tank 21 through the outer tank 31 and the propagation liquid 33, and further, the ultrasonic wave is applied to the internal cleaning liquid to enhance the cleaning effect.
  • the semiconductor material 100 is disposed in the cleaning tank 21 so as to be immersed in the cleaning liquid in this state, the cured resist attached to the surface of the semiconductor material 100 by the cleaning liquid to which the ultrasonic action is applied is effectively used. Removed.
  • the amount of dissolved gas in the cleaning liquid is sufficiently low, and the action of ultrasonic waves is sufficiently obtained.
  • An appropriate number of semiconductor materials 100 can be washed at a time. The cleaning time can be appropriately set according to the cleaning effect and the like.
  • the cleaning may be performed while feeding the electrolytic sulfuric acid solution by the liquid feeding pump 23.
  • the excess cleaning liquid is drained from the cleaning tank 21, cooled to an appropriate temperature, for example, 10 to 90 ° C. by the cooler 27 through the drain line 26, and moved to the electrolyte storage tank 15.
  • the cleaning tank 21 is installed at a position higher than the electrolytic solution storage tank 15, the cleaning liquid moves from the cleaning tank 21 to the electrolytic solution storage tank 15 by atmospheric pressure. If movement by atmospheric pressure is impossible, a reflux pump or the like is installed in the drain line 26 to forcibly feed the liquid.
  • the cleaning liquid sent to the electrolytic solution storage tank 15 is further fed by the circulation pump 13 through the electrolysis side circulation line 12 and cooled by the cooler 14 and is sent to the electrolysis apparatus 10, and is passed through as described above.
  • electrolysis can be performed.
  • the cleaning liquid can be regenerated as an electrolytic sulfuric acid solution, and electrolysis and degassing are repeated through the electrolytic side circulation line 12.
  • the persulfuric acid concentration of the electrolytic sulfuric acid solution can be used for cleaning while maintaining it in an appropriate range.
  • drainage, electrolysis, and supply may be performed continuously or intermittently.
  • the cleaning device 1 a includes an electrolysis device 10 and a cleaning unit 40.
  • the electrolyzer 10 is a non-diaphragm type, and an anode 11a and a cathode 11b each having at least a portion in contact with a sulfuric acid solution as a diamond electrode are arranged inside without being separated by a diaphragm, and a DC power source (not shown) is connected to both electrodes.
  • An electrolytic solution storage tank 15 is connected to the electrolysis apparatus 10 through an electrolysis-side circulation line 12 so as to be able to circulate, and the electrolysis-side circulation line 12 on the feed side is cooled with a circulation pump 13 for circulating a sulfuric acid solution.
  • a container 14 is interposed in order.
  • a gas-liquid separator 16 is interposed in the return-side electrolysis-side circulation line 12.
  • the gas-liquid separator 16 corresponds to the gas-liquid separator of the present invention.
  • the gas-liquid separator 16 can be configured by using gravity or centrifugal force, but the present invention is not limited to a specific configuration.
  • a liquid supply line 22 is connected to the electrolytic solution storage tank 15 via a liquid supply pump 23.
  • the liquid feed line 22 corresponds to the cleaning liquid supply line of the present invention.
  • a degassing device 24 is provided in the liquid feed line 22 on the downstream side of the liquid feed pump 23.
  • the deaeration device 24 corresponds to the deaeration unit of the present invention.
  • the deaeration device 24 can be constituted by a deaeration membrane or an aspirator, but the present invention is not limited to a specific configuration.
  • the liquid feed line 22 is provided with a heater 28 on the downstream side of the deaeration device 24, and for example, the cleaning liquid is heated to a liquid temperature of 40 to 95 ° C. in a transient manner.
  • the heater 28 has a pipeline made of, for example, quartz, and heats the electrolytic sulfuric acid solution in a transient manner with a near infrared heater.
  • the liquid feed front end side of the liquid feed line 22 is connected to the nozzle 41 of the single wafer cleaning unit 40.
  • the ultrasonic transducer 35 is disposed inside the nozzle 41, and ultrasonic waves are applied to the electrolytic sulfuric acid solution flowing through the nozzle 41. Therefore, the nozzle 41 also has a function as an ultrasonic wave imparting device.
  • the nozzle 41 is installed so that the nozzle 41 is positioned toward the semiconductor material 100 carried in, and an electrolytic sulfuric acid solution as a cleaning solution is sprayed from the nozzle 41 or a small amount. It flows down one by one. In the spray direction and the flow-down direction, a turntable 42 for placing and rotating the semiconductor material 100 is provided.
  • a cleaning liquid disposal line 43 and a drainage line 44 are connected to the cleaning unit 40.
  • a first circulating pump 45 is interposed in the drainage line 44, and a decomposition tank 46 for temporarily storing the cleaning liquid is interposed in the drainage line 44 on the downstream side thereof.
  • a second circulating pump 47 is further provided in the drainage line 44, and on the downstream side thereof, the downstream end of the drainage line 44 is connected to the electrolyte storage tank 15 via the cooler 48. ing.
  • the semiconductor material 100 with high dose implantation is used as a material to be cleaned, and is placed on the turntable 42.
  • the electrolytic solution storage tank 15 a sulfuric acid solution having a sulfuric acid concentration of 75 to 96% by mass (preferably 80 to 92% by mass) is stored.
  • the sulfuric acid solution is fed through the electrolysis-side circulation line 12 by the circulation pump 13, cooled by the cooler 14 (temperature in the electrolysis apparatus 10) to 10 to 90 ° C., and then enters the electrolysis apparatus 10. Introduced on the side.
  • a DC power source is energized between the anode 11a and the cathode 11b so that the current density is 10 to 10,000 A / m 2 with respect to the electrode area, and the sulfuric acid solution introduced into the electrolyzer 10 is the electrode surface. 1 to 10,000 m / hr. Electrolysis is performed while passing the liquid at a linear speed of. In the electrolysis apparatus 10, an oxidizing substance containing persulfuric acid is generated on the anode 11a side by electrolysis.
  • the oxidizing substance is sent to the outside of the electrolysis apparatus 10 in a state of being mixed with the sulfuric acid solution, separated into gas and liquid by the gas / liquid separator 16, and then returned to the electrolyte storage tank 15 through the electrolysis side circulation line 12. .
  • the sulfuric acid solution is returned to the electrolytic solution storage tank 15 through the electrolytic side circulation line 12, and then repeatedly sent to the electrolytic device 10, where the concentration of persulfuric acid is increased by electrolysis.
  • the persulfuric acid concentration include 2 to 20 g as S 2 O 8 2 ⁇ / L in units of peroxodisulfuric acid.
  • the persulfuric acid concentration becomes moderate, a part of the sulfuric acid solution in the electrolytic solution storage tank 15 is fed through the liquid feeding line 22 by the liquid feeding pump 23.
  • the sulfuric acid solution flowing through the liquid feed line 22 is deaerated by the deaerator 24, heated to 40 to 95 ° C. by the heater 28, and sent to the cleaning unit 40. If the electrolytic sulfuric acid solution to be fed has the appropriate liquid temperature, heating by the heater 28 is not necessarily required.
  • the electrolytic sulfuric acid solution is sent to the nozzle 41, and ultrasonic waves of 20 kHz to 5 MHz are applied to the electrolytic sulfuric acid solution flowing in the nozzle 41 by the operation of the ultrasonic vibrator 35 in the nozzle 41.
  • the electrolytic sulfuric acid solution comes into contact with the semiconductor material 100 on the turntable 42 as a cleaning liquid by spraying or flowing down, and adheres to the surface of the semiconductor material 100 by the cleaning liquid provided with ultrasonic action.
  • the cured resist that is present is effectively removed.
  • the cleaning time can be appropriately set according to the cleaning effect and the like.
  • the cleaning liquid used for the cleaning gradually flows down in the main body of the cleaning unit 40 and is taken out by the waste line 43 and the drain line 44.
  • the disposal line 43 can dispose of unnecessary cleaning liquid outside the system by opening an on-off valve (not shown) as needed.
  • the cleaning liquid taken out from the drainage line 44 is temporarily stored in the decomposition tank 46 by the first recirculation pump 45 and decomposes the resist removed from the semiconductor material 100.
  • the temporary storage time can be set as appropriate.
  • the cleaning solution temporarily stored in the decomposition tank 46 is further sent by the second circulation pump 47 through the drainage line 44 on the downstream side, and cooled to an appropriate temperature, for example, 10 to 90 ° C. by the cooler 48, and is stored in the electrolyte storage tank 15. Sent to.
  • the cleaning liquid sent to the electrolytic solution storage tank 15 is further fed by the circulation pump 13 through the electrolysis side circulation line 12 and cooled by the cooler 14 and is sent to the electrolysis apparatus 10, and is passed through as described above.
  • electrolysis can be performed.
  • the cleaning liquid can be regenerated as an electrolytic sulfuric acid solution, and electrolysis and degassing are repeated through the electrolytic side circulation line 12.
  • the persulfuric acid concentration of the electrolytic sulfuric acid solution can be used for cleaning while maintaining it in an appropriate range.
  • an oxidizing agent activation test and a cured resist peeling test were performed by the following methods.
  • Test conditions / Examples The temperature of the electrolytic sulfuric acid solution was set to 20, 40, 60, and 80 ° C., and ultrasonic waves of 28, 45, 100, and 750 kHz were irradiated for 30 minutes.
  • the oxidant concentration before and after ultrasonic irradiation was titrated with potassium iodide to determine the presence or absence of activation.
  • Table 1 shows the test results.
  • Table 1 shows the oxidant decomposition rate (%) when the electrolytic sulfuric acid solution was treated for 30 minutes. In the examples, it can be seen that when the liquid temperature is set to 40 ° C. or higher, the oxidant concentration is lowered and activated. Under any condition, the oxidizing agent was not decomposed. On the other hand, the decomposition rate of SPM was less than 5% and hardly decomposed.
  • Test conditions and examples The liquid temperature was set to 60 and 80 ° C., the Si wafer was immersed in the treatment solution, and ultrasonic waves of 28, 45, 100 and 750 kHz were irradiated for 10 minutes. Comparative Example: The liquid temperature was set to 60 ° C., the Si wafer was immersed, and irradiated with 45 kHz ultrasonic waves for 10 minutes.
  • FIGS. 4 (a) and 4 (b) Test results and post-test Si wafer micrographs (surface laser micrograph magnification 500 times) are shown in FIGS. 4 (a) and 4 (b).
  • FIG. 4A is an example, which was tested at a liquid temperature of 60 ° C. and an ultrasonic wave of 45 kHz
  • FIG. 4B was a comparative example, which was tested at a liquid temperature of 60 ° C. and an ultrasonic wave of 45 kHz. Is.
  • the resist was completely peeled off under any condition, but in the comparative example, the resist was not completely peeled off and partly remained.

Abstract

Using a cleaning device provided with an electrolysis device (10) that carries out electrolysis of a sulfuric acid solution, a cleaning unit (20) that cleans a material to be cleaned (100) with an electrolyzed sulfuric acid solution, which has been electrolyzed and generated by the electrolysis device (10), as a cleaning fluid, a cleaning fluid supply line (22) that supplies the electrolyzed sulfuric acid solution that has been electrolyzed by the electrolysis device (10) to the cleaning unit (20), and an ultrasonic wave application device (30), which applies ultrasonic waves to the electrolyzed sulfuric acid solution used by the cleaning unit (20), ultrasonic waves are applied to the electrolyzed sulfuric acid solution electrolyzed and generated from the sulfuric acid solution, and surface cleaning is carried out on the material to be cleaned (100) by the electrolyzed sulfuric acid solution to which the ultrasonic waves have been applied. Thereby, a cleaning effect sufficient even for semiconductor materials to which hardened resist has adhered can be exhibited without reducing streaming and cavitation effects due to the ultrasonic waves.

Description

洗浄方法および洗浄装置Cleaning method and cleaning device
　この発明は、電解した硫酸溶液を洗浄液として使用する洗浄方法および洗浄装置に関する。 The present invention relates to a cleaning method and a cleaning apparatus that use an electrolyzed sulfuric acid solution as a cleaning liquid.
　半導体や液晶基板などを製造する工程では、ドーズインプラ工程やドライエッチング工程で保護膜として塗布したレジストを除去するレジスト剥離工程が含まれる。
　レジストは有機物であるため、一般には有機溶媒や硫酸／過酸化水素（ＳＰＭ：Sulfuric Acid Hydrogen Peroxide Mixture）により剥離する。ところが、高ドーズインプラや高速ドライエッチングの条件では、高エネルギーのイオン注入によりレジストが硬化し、従来の有機溶媒やＳＰＭによる剥離が困難になる。
　硬化レジストは一部がグラファイト化しており、材料表面に固着している。このような硬化レジストを剥離することを意図してＳＰＭを用いた改良方法が提案されている（特許文献１）。
　すなわち、特許文献１には、超音波振動が付与されたＳＰＭを基板の表面に供給し、硬化層を超音波振動の物理的なエネルギーによって破壊しつつ剥離する洗浄方法が開示されている。 The process of manufacturing a semiconductor, a liquid crystal substrate, or the like includes a resist stripping process that removes a resist applied as a protective film in a dose implantation process or a dry etching process.
Since the resist is an organic substance, it is generally removed by an organic solvent or sulfuric acid / hydrogen peroxide (SPM). However, under the conditions of high dose implantation and high-speed dry etching, the resist is cured by high-energy ion implantation, and peeling with a conventional organic solvent or SPM becomes difficult.
A part of the cured resist is graphitized and is fixed to the material surface. An improved method using SPM has been proposed with the intention of peeling such a cured resist (Patent Document 1).
That is, Patent Document 1 discloses a cleaning method in which SPM to which ultrasonic vibration is applied is supplied to the surface of the substrate, and the cured layer is peeled off while being destroyed by the physical energy of ultrasonic vibration.
特開２００８－４８７９号公報JP 2008-4879 A
　しかしながら、特許文献１で提案されている洗浄方法によっても、十分な洗浄効果が得られるにはいたっていない。その原因は、ＳＰＭが超音波振動時に発泡するため超音波洗浄効果の大半が失われてしまうためである。
　超音波照射によりＳＰＭが発泡する原理を以下に示す。
　ＳＰＭは硫酸と過酸化水素の混合液であり、以下の反応により生成したカロ酸を含んでいる。
　　Ｈ２ＳＯ４＋Ｈ２Ｏ２　→　Ｈ２ＳＯ５（カロ酸）＋Ｈ２Ｏ
　カロ酸は外部エネルギー（熱など）やレジストとの反応によりＨ２ＳＯ４とＯ２ガスに分解し、分解時のラジカル作用（＝活性化）によりレジストの酸化分解・剥離を促進する。したがってＳＰＭを洗浄に使用する際、溶液はＯ２ガスの微細気泡が発生し白濁する。 However, even the cleaning method proposed in Patent Document 1 does not provide a sufficient cleaning effect. The reason is that the SPM foams during ultrasonic vibration, so that most of the ultrasonic cleaning effect is lost.
The principle of foaming of SPM by ultrasonic irradiation is shown below.
SPM is a mixed liquid of sulfuric acid and hydrogen peroxide, and contains caroic acid generated by the following reaction.
H 2 SO 4 + H 2 O 2 → H 2 SO 5 (caroic acid) + H 2 O
Caroic acid is decomposed into H 2 SO 4 and O 2 gas by reaction with external energy (heat, etc.) and resist, and promotes oxidative decomposition and peeling of the resist by radical action (= activation) at the time of decomposition. Therefore, when the SPM is used for cleaning, fine bubbles of O 2 gas are generated in the solution and become cloudy.
　発泡により洗浄効果が失われる機構は以下の理由による。
　気泡発生により、以下２つの機構で洗浄効果が失われる。
（１）超音波は直進流で伝搬するため、微細気泡があると直進性が遮られ洗浄効果が失われる。
（２）Ｏ２ガス発生によりＳＰＭ中はＯ２が過飽和状態である。超音波の洗浄効果の一つはキャビテーション（真空気泡の発生と消失によるエネルギー発生）であるが、溶存ガスが存在するとキャビテーション中にガスが入り込み、その効果が失われる。
　キャビテーション効果が失われるとカロ酸の活性化やキャビテーションによるレジスト剥離効果が発揮できず、洗浄できない。 The mechanism by which the cleaning effect is lost by foaming is as follows.
Due to the generation of bubbles, the cleaning effect is lost by the following two mechanisms.
(1) Since the ultrasonic wave propagates in a straight flow, if there are fine bubbles, the straight travel is blocked and the cleaning effect is lost.
(2) SPM in the O 2 gas generated O 2 is supersaturated. One of the ultrasonic cleaning effects is cavitation (energy generation due to generation and disappearance of vacuum bubbles), but if dissolved gas is present, the gas enters the cavitation and the effect is lost.
If the cavitation effect is lost, the resist stripping effect due to the activation of caloic acid and cavitation cannot be exhibited, and cleaning cannot be performed.
　本発明は、上記事情を背景としてなされたものであり、硫酸溶液を電気分解して生成した電解硫酸溶液に超音波を併用することで、超音波洗浄効果を十分に発揮できるようにした洗浄方法および洗浄装置を提供することを目的とする。 The present invention has been made against the background of the above circumstances, and a cleaning method capable of sufficiently exerting an ultrasonic cleaning effect by using ultrasonic waves in combination with an electrolytic sulfuric acid solution generated by electrolyzing a sulfuric acid solution. And it aims at providing a washing device.
　すなわち、本発明の洗浄方法のうち、第１の本発明は、硫酸溶液を電気分解し生成した電解硫酸溶液に超音波を付与し、前記超音波を付与した前記電解硫酸溶液で被洗浄材の表面洗浄を行うことを特徴とする。 That is, among the cleaning methods of the present invention, the first present invention provides ultrasonic waves to an electrolytic sulfuric acid solution generated by electrolyzing a sulfuric acid solution, and the electrolytic sulfuric acid solution to which the ultrasonic waves are applied is used to clean the material to be cleaned. Surface cleaning is performed.
　第２の本発明の洗浄方法は、前記第１の本発明において、前記洗浄に用いる前記電解硫酸溶液の温度が４０℃以上であることを特徴とする。 The cleaning method of the second aspect of the present invention is characterized in that, in the first aspect of the present invention, the temperature of the electrolytic sulfuric acid solution used for the cleaning is 40 ° C. or higher.
　第３の本発明の洗浄方法は、前記第１または第２の本発明において、前記洗浄に用いる前記電解硫酸溶液の温度が９５℃以下であることを特徴とする。 The cleaning method of the third aspect of the present invention is characterized in that, in the first or second aspect of the present invention, the temperature of the electrolytic sulfuric acid solution used for the cleaning is 95 ° C. or less.
　第４の本発明の洗浄方法は、前記第１～第３の本発明のいずれかにおいて、前記超音波の周波数を２０ｋＨｚ～５ＭＨｚとすることを特徴とする。 The cleaning method of the fourth aspect of the present invention is characterized in that, in any of the first to third aspects of the present invention, the frequency of the ultrasonic wave is 20 kHz to 5 MHz.
　第５の本発明の洗浄方法は、前記第１～第４の本発明のいずれかにおいて、前記被洗浄材がレジストが付着した電子材料であることを特徴とする。 The cleaning method of the fifth aspect of the present invention is characterized in that, in any of the first to fourth aspects of the present invention, the material to be cleaned is an electronic material to which a resist is attached.
　第６の本発明の洗浄方法は、前記第１～５の本発明のいずれかにおいて、前記電解硫酸溶液に超音波を付与する前に前記電解硫酸溶液の気液分離を行うことを特徴とする。 The cleaning method of the sixth aspect of the present invention is characterized in that in any one of the first to fifth aspects of the present invention, the electrolytic sulfuric acid solution is subjected to gas-liquid separation before applying ultrasonic waves to the electrolytic sulfuric acid solution. .
　第７の本発明の洗浄方法は、前記第６の本発明において、前記気液分離をした後、前記電解硫酸溶液に超音波を付与する前に、前記電解硫酸溶液の脱気処理を行うことを特徴とする。 In the cleaning method of the seventh aspect of the present invention, in the sixth aspect of the present invention, after the gas-liquid separation, the electrolytic sulfuric acid solution is degassed before applying ultrasonic waves to the electrolytic sulfuric acid solution. It is characterized by.
　第８の本発明の洗浄装置は、硫酸溶液を電解する電解装置と、
　前記電解装置で電解されて生成された電解硫酸溶液を洗浄液として被洗浄材を洗浄する洗浄部と、
　前記電解装置で電解された電解硫酸溶液を前記洗浄部に供給する洗浄液供給ラインと、
　前記洗浄部で使用される前記電解硫酸溶液に超音波を付与する超音波付与装置と、を備えることを特徴とする。 The cleaning device of the eighth aspect of the present invention includes an electrolytic device for electrolyzing a sulfuric acid solution,
A cleaning section for cleaning the material to be cleaned using an electrolytic sulfuric acid solution generated by electrolysis in the electrolysis apparatus as a cleaning liquid;
A cleaning liquid supply line for supplying an electrolytic sulfuric acid solution electrolyzed by the electrolytic device to the cleaning unit;
And an ultrasonic application device that applies ultrasonic waves to the electrolytic sulfuric acid solution used in the cleaning section.
　第９の本発明の洗浄装置は、前記第８の本発明において、前記超音波付与の前に前記電解硫酸溶液の気液分離を行う気液分離部をさらに備えることを特徴とする。 The cleaning apparatus according to a ninth aspect of the present invention is the cleaning apparatus according to the eighth aspect, further comprising a gas-liquid separation unit that performs gas-liquid separation of the electrolytic sulfuric acid solution before applying the ultrasonic wave.
　第１０の本発明の洗浄装置は、前記第９の本発明において、前記気液分離部の後に、前記超音波付与の前に前記電解硫酸溶液の脱気を行う脱気部を備えることを特徴とする。 A cleaning apparatus according to a tenth aspect of the present invention is the cleaning apparatus according to the ninth aspect, further comprising a deaeration unit that degass the electrolytic sulfuric acid solution before the ultrasonic wave application after the gas-liquid separation unit. And
　第１１の本発明の洗浄装置は、前記第８～第１０の本発明のいずれかにおいて、さらに、前記洗浄部で用いられる前記電解硫酸溶液を加熱する加熱部を備えることを特徴とする。 The eleventh aspect of the present invention is the cleaning apparatus according to any one of the eighth to tenth aspects of the present invention, further comprising a heating unit for heating the electrolytic sulfuric acid solution used in the cleaning unit.
　第１２の本発明の洗浄装置は、前記第８～第１１の本発明のいずれかにおいて、前記洗浄部が、１または２以上の被洗浄材を洗浄槽の洗浄液に浸漬して洗浄するバッチ式であり、前記超音波付与装置は、前記洗浄槽に超音波を伝播させるものであることを特徴とする。 The cleaning apparatus of the twelfth aspect of the present invention is the batch type according to any one of the eighth to eleventh aspects of the present invention, wherein the cleaning section immerses and cleans one or two or more materials to be cleaned in a cleaning liquid in a cleaning tank. And the ultrasonic wave imparting device propagates ultrasonic waves to the cleaning tank.
　第１３の本発明の洗浄装置は、前記第８～第１１の本発明のいずれかにおいて、前記洗浄部が１または２以上の被洗浄材に洗浄液を送液しつつ接触させて洗浄する枚葉式であり、前記超音波付与装置は、前記洗浄液を前記被洗浄材に向けて送液するノズル内で前記被洗浄材に前記超音波を伝播させるものであることを特徴とする。 A cleaning apparatus according to a thirteenth aspect of the present invention is the cleaning apparatus according to any one of the eighth to eleventh aspects, wherein the cleaning section contacts and cleans one or more materials to be cleaned while feeding the cleaning liquid. The ultrasonic applicator propagates the ultrasonic wave to the material to be cleaned in a nozzle that feeds the cleaning liquid toward the material to be cleaned.
　本発明では、上記したように、硫酸溶液を電解して得た電解硫酸溶液が洗浄液として用いられる。電解硫酸溶液はＳＰＭと比べ、理由は明らかでないが超音波併用時の気泡の発生量が著しく低い。このため超音波を併用しても、その直進流・キャビテーション効果が気泡により低減せず十分な洗浄効果を発揮できると考えられる。しかも、電解硫酸溶液にはペルオキソ二硫酸などの酸化剤が含まれるため、硫酸溶液よりも有機汚染物の除去効果が高い。 In the present invention, as described above, an electrolytic sulfuric acid solution obtained by electrolyzing a sulfuric acid solution is used as a cleaning liquid. Compared with SPM, the electrolytic sulfuric acid solution has an extremely low amount of bubbles generated when ultrasonic waves are used, although the reason is not clear. For this reason, even if ultrasonic waves are used in combination, it is considered that the straight flow / cavitation effect is not reduced by bubbles and a sufficient cleaning effect can be exhibited. Moreover, since the electrolytic sulfuric acid solution contains an oxidizing agent such as peroxodisulfuric acid, the organic contaminant removal effect is higher than that of the sulfuric acid solution.
　硫酸溶液を電解する際の電極材料は特に限定しないが、酸素発生過電圧が高い材料が好ましく、ホウ素等の導電性物質をドープしたダイヤモンド電極が更に好ましい。ダイヤモンド電極は、硫酸溶液と接液する部位に設けるのが望ましく、特に陽極に用いるのが望ましい。同様に陰極にダイヤモンド電極を用いることができる。 The electrode material for electrolyzing the sulfuric acid solution is not particularly limited, but a material having a high oxygen generation overvoltage is preferable, and a diamond electrode doped with a conductive substance such as boron is more preferable. The diamond electrode is preferably provided at a site in contact with the sulfuric acid solution, and particularly preferably used for the anode. Similarly, a diamond electrode can be used for the cathode.
　電解される硫酸溶液の濃度は特に限定しない。ステンレス鋼の酸洗などに用いる場合は、希硫酸（質量％で２０％以下）が好ましく、硬化レジスト剥離に用いる場合は硫酸のレジスト内部への浸透力の関係から質量％で７５～９６％が好ましく、更に８０～９２％が好ましい。 The concentration of the sulfuric acid solution to be electrolyzed is not particularly limited. When used for pickling stainless steel, etc., dilute sulfuric acid (20% or less by mass) is preferable. When used for removing a cured resist, 75 to 96% by mass is used because of the permeation power of sulfuric acid into the resist. More preferably, it is 80 to 92%.
　電解時の電流密度は電極面積に対し１０～１０，０００Ａ／ｍ２が好ましく、硫酸溶液を電極面と並行方向に、１～１０，０００ｍ／ｈｒ．の線速で通液しつつ接触処理させるのが好ましい。
　電解時の液温度は、電解効率や電解液中酸化剤の自己分解を防ぐため１０～９０℃が好ましい。 The current density during electrolysis is preferably 10 to 10,000 A / m 2 with respect to the electrode area, and the sulfuric acid solution is applied in the direction parallel to the electrode surface to 1 to 10,000 m / hr. It is preferable to carry out the contact treatment while passing the liquid at a linear velocity.
The liquid temperature during electrolysis is preferably 10 to 90 ° C. in order to prevent electrolysis efficiency and self-decomposition of the oxidizing agent in the electrolytic solution.
　電解硫酸溶液の前処理方法は特に限定しないが、電解時に電極表面で酸素ガスや水素ガスが発生し液と混合するため超音波を付与する前に予め気液分離し、さらに脱気するのが好ましい。気液分離には動力や遠心力を利用したものや透過膜を利用したものを用いることができるがこれに限定されず、電解液と電解ガスとを分離して電解液を利用可能とするものであればよい。脱気には脱気膜やアスピレーターを用いることができる。脱気時間は５～１０分が好ましい。 The pretreatment method of the electrolytic sulfuric acid solution is not particularly limited, but oxygen gas or hydrogen gas is generated on the electrode surface during electrolysis and mixed with the liquid, so that it is preliminarily gas-liquid separated and then degassed before applying ultrasonic waves. preferable. For gas-liquid separation, one using power or centrifugal force or one using a permeable membrane can be used, but the invention is not limited to this, and the electrolytic solution can be used by separating the electrolytic solution and the electrolytic gas. If it is. A degassing membrane or an aspirator can be used for degassing. The deaeration time is preferably 5 to 10 minutes.
　また、電解硫酸溶液に付与する超音波の周波数は２０ｋＨｚ以上５ＭＨｚ以下が例示される。
　超音波を付与して洗浄に用いる電解硫酸溶液は、液温を４０℃以上にするのが望ましい。４０℃未満では電解液中の酸化剤が活性化しにくい。
　また、液温は、９５℃以下とするのが望ましい。液温度を９５℃超とすると、材料や超音波伝播用の溶媒をシリコンオイル等沸点の高いものに変更する必要がある。また、温度が高いと自己分解が早期に進行しやすい。 The frequency of the ultrasonic wave applied to the electrolytic sulfuric acid solution is 20 kHz or more and 5 MHz or less.
It is desirable that the electrolytic sulfuric acid solution used for cleaning by applying ultrasonic waves has a liquid temperature of 40 ° C. or higher. If it is less than 40 degreeC, the oxidizing agent in electrolyte solution will be hard to activate.
The liquid temperature is desirably 95 ° C. or lower. If the liquid temperature exceeds 95 ° C., it is necessary to change the material and the solvent for propagating ultrasonic waves to those having a high boiling point such as silicon oil. In addition, when the temperature is high, the self-decomposition tends to proceed early.
　すなわち、本発明によれば、超音波によるキャビテーション作用と過硫酸との作用が十分に得られ、高い洗浄作用が得られ、例えば、半導体材料の硬化したレジストにおいても効果的に剥離する効果がある。 That is, according to the present invention, the action of cavitation by ultrasonic waves and the action of persulfuric acid can be sufficiently obtained, and a high cleaning action can be obtained. For example, even in a resist cured with a semiconductor material, there is an effect of effective peeling. .
本発明の一実施形態の洗浄装置を示す図である。It is a figure which shows the washing | cleaning apparatus of one Embodiment of this invention. 同じく、他の実施形態の洗浄装置を示す図である。Similarly, it is a figure which shows the washing | cleaning apparatus of other embodiment. 同じく、ノズルの内部を示す拡大図である。Similarly, it is an enlarged view showing the inside of a nozzle. 同じく、実施例における洗浄効果を示す半導体材料のレジスト剥離写真を示す図である。Similarly, it is a figure which shows the resist peeling photograph of the semiconductor material which shows the cleaning effect in an Example.
（実施形態１）
　以下、この発明の洗浄装置の実施形態を、図１に基づいて説明する。
　洗浄装置１は、電解装置１０と、洗浄部２０とを備えている。
　電解装置１０は無隔膜型であり、少なくとも硫酸溶液と接液する部分をダイヤモンド電極とした陽極１１ａおよび陰極１１ｂが隔膜で隔てることなく内部に配置され、両電極には図示しない直流電源が接続されている。なお、本発明としては、電解装置を隔膜型によって構成することも可能であり、また無隔膜型であってバイポーラ電極を陽極１１ａと陰極１１ｂの間に配置したものであってもよい。
　上記電解装置１０には、電解液貯留槽１５が電解側循環ライン１２を介して循環通液可能に接続されている。電解液貯留槽１５から電解装置１０に向けた送り側の電解側循環ライン１２には、硫酸溶液を循環させる循環ポンプ１３と冷却器１４とが順に介設されている。また、電解装置１０から電解液貯留槽１５に向けた戻り側の電解側循環ライン１２には、気液分離器１６が介設されている。気液分離器１６は、気液分離部に相当する。気液分離器１６としては重力や遠心力を利用したものにより構成することができるが、本発明としては特定の構成に限定されない。 (Embodiment 1)
Hereinafter, an embodiment of a cleaning apparatus of the present invention will be described with reference to FIG.
The cleaning device 1 includes an electrolysis device 10 and a cleaning unit 20.
The electrolyzer 10 is a non-diaphragm type, and an anode 11a and a cathode 11b each having at least a portion in contact with a sulfuric acid solution as a diamond electrode are arranged inside without being separated by a diaphragm, and a DC power source (not shown) is connected to both electrodes. ing. In the present invention, the electrolysis apparatus may be configured as a diaphragm type, or may be a non-diaphragm type in which a bipolar electrode is disposed between the anode 11a and the cathode 11b.
An electrolytic solution storage tank 15 is connected to the electrolyzer 10 through an electrolytic side circulation line 12 so as to be circulated. A circulation pump 13 for circulating the sulfuric acid solution and a cooler 14 are provided in this order on the electrolytic side circulation line 12 on the feed side from the electrolytic solution storage tank 15 toward the electrolytic device 10. A gas-liquid separator 16 is interposed in the return-side electrolysis-side circulation line 12 from the electrolyzer 10 toward the electrolyte storage tank 15. The gas-liquid separator 16 corresponds to a gas-liquid separator. The gas-liquid separator 16 can be configured by using gravity or centrifugal force, but the present invention is not limited to a specific configuration.
　電解液貯留槽１５には、送液ポンプ２３を介して送液ライン２２が接続されている。送液ライン２２は、洗浄液供給ラインに相当する。また、送液ライン２２には送液ポンプ２３の下流側に脱気装置２４が設けられている。脱気装置２４は、脱気部に相当する。脱気装置２４としては、脱気膜やアスピレーターなどにより構成することができるが、本発明としては特定の構成に限定されない。
　送液ライン２２の送液先端側は、バッチ式の洗浄部２０の洗浄槽２１に接続されている。洗浄槽２１には、収容した洗浄液を加熱する加熱器２５が備えられており、例えば洗浄液を４０～９５℃の液温に加熱する。 A liquid feed line 22 is connected to the electrolytic solution storage tank 15 via a liquid feed pump 23. The liquid feed line 22 corresponds to a cleaning liquid supply line. Further, a degassing device 24 is provided in the liquid feed line 22 on the downstream side of the liquid feed pump 23. The deaeration device 24 corresponds to a deaeration unit. The deaeration device 24 can be constituted by a deaeration membrane or an aspirator, but the present invention is not limited to a specific configuration.
The liquid feed front end side of the liquid feed line 22 is connected to the cleaning tank 21 of the batch type cleaning unit 20. The cleaning tank 21 is provided with a heater 25 for heating the stored cleaning liquid. For example, the cleaning liquid is heated to a liquid temperature of 40 to 95 ° C.
　洗浄槽２１は、内槽として外槽３１内に収容されており、内外槽間には、伝搬液３３としてシリコンオイルなどが満たされている。伝搬液の種別は特に限定されないが、洗浄液の温度に対する耐熱性を有し、また超音波を効率よく伝搬できるように、粘度の高いものが望ましい。
　外槽３１の外壁には超音波振動子３２が取り付けられている。超音波振動子３２、外槽３１、伝搬液３３により超音波付与装置３０が構成されている。なお、超音波振動子を直接洗浄槽２１に取り付けて超音波付与装置を構成するものであってもよい。超音波振動子３２には、周波数２０ｋＨｚ以上、５ＭＨｚ以下の超音波を発生するものを用いる。 The cleaning tank 21 is housed in the outer tank 31 as an inner tank, and between the inner and outer tanks, silicon oil or the like is filled as the propagation liquid 33. The type of the propagating liquid is not particularly limited, but it is desirable that the propagating liquid has high heat resistance with respect to the temperature of the cleaning liquid and can transmit ultrasonic waves efficiently.
An ultrasonic transducer 32 is attached to the outer wall of the outer tub 31. An ultrasonic applicator 30 is configured by the ultrasonic transducer 32, the outer tank 31, and the propagation liquid 33. Note that the ultrasonic wave applying device may be configured by directly attaching the ultrasonic vibrator to the cleaning tank 21. As the ultrasonic transducer 32, one that generates ultrasonic waves having a frequency of 20 kHz or more and 5 MHz or less is used.
　また、洗浄槽２１には、排液ライン２６が接続されている。排液ライン２６には、冷却器２７が介設されており、排液ライン２６を流れる洗浄液を適宜の温度に冷却する。排液ライン２６の先端側は、電解液貯留槽１５に接続されている。 Further, a drain line 26 is connected to the cleaning tank 21. A cooler 27 is interposed in the drainage line 26 to cool the cleaning liquid flowing through the drainage line 26 to an appropriate temperature. The front end side of the drainage line 26 is connected to the electrolyte storage tank 15.
　次に、上記構成からなる洗浄装置の動作について説明する
　この実施形態では、高ドーズインプラがされた半導体材料１００を被洗浄材とする。本実施形態等では、レジストが付着した電子材料などを被洗浄材とすることができる。
　電解液貯留槽１５には、硫酸濃度７５～９６質量％（好適には８０～９２質量％）の硫酸溶液が貯留される。前記硫酸溶液は、循環ポンプ１３により電解側循環ライン１２を通じて送液され、冷却器１４で（電解装置１０内での温度が）１０～９０℃になるように冷却されて電解装置１０の入液側に導入される。 Next, the operation of the cleaning apparatus having the above-described configuration will be described. In this embodiment, the semiconductor material 100 subjected to high dose implantation is used as the cleaning target material. In this embodiment and the like, an electronic material or the like to which a resist is attached can be used as a material to be cleaned.
In the electrolytic solution storage tank 15, a sulfuric acid solution having a sulfuric acid concentration of 75 to 96% by mass (preferably 80 to 92% by mass) is stored. The sulfuric acid solution is fed through the electrolysis-side circulation line 12 by the circulation pump 13, cooled by the cooler 14 (temperature in the electrolysis apparatus 10) to 10 to 90 ° C., and then enters the electrolysis apparatus 10. Introduced on the side.
　電解装置１０では、直流電源によって陽極１１ａ、陰極１１ｂ間に電流密度が電極面積に対し１０～１０，０００Ａ／ｍ２となるように通電され、電解装置１０内に導入された硫酸溶液が電極面と並行方向に、１～１０，０００ｍ／ｈｒ．の線速で通液しつつ電解される。線速は、循環ポンプ１３の送量によって調整できる。
　電解によって電解装置１０では、陽極１１ａ側で過硫酸を含む酸化性物質が生成される。酸化性物質は、前記硫酸溶液と混在した状態で電解装置１０外に送液され、気液分離器１６で気液分離された後、電解側循環ライン１２を通じて電解液貯留槽１５に返送される。硫酸溶液は、過硫酸を含んでおり、電解側循環ライン１２を通じて、電解液貯留槽１５に戻された後、繰り返し電解装置１０に送られ、電解により過硫酸の濃度が高められる。過硫酸濃度としては、例えばペルオキソ二硫酸の単位で２～２０ｇ　ａｓ　Ｓ２Ｏ８ ２－ ／Ｌが挙げられる。 In the electrolyzer 10, a DC power source is energized between the anode 11a and the cathode 11b so that the current density is 10 to 10,000 A / m 2 with respect to the electrode area, and the sulfuric acid solution introduced into the electrolyzer 10 is the electrode surface. 1 to 10,000 m / hr. Electrolysis is performed while passing the liquid at a linear speed of. The linear speed can be adjusted by the feed amount of the circulation pump 13.
In the electrolysis apparatus 10, an oxidizing substance containing persulfuric acid is generated on the anode 11a side by electrolysis. The oxidizing substance is sent to the outside of the electrolysis apparatus 10 in a state of being mixed with the sulfuric acid solution, separated into gas and liquid by the gas / liquid separator 16, and then returned to the electrolyte storage tank 15 through the electrolysis side circulation line 12. . The sulfuric acid solution contains persulfuric acid, is returned to the electrolytic solution storage tank 15 through the electrolytic side circulation line 12, and then repeatedly sent to the electrolyzer 10, where the concentration of persulfuric acid is increased by electrolysis. Examples of the persulfuric acid concentration include 2 to 20 g as S 2 O 8 2− / L in units of peroxodisulfuric acid.
　過硫酸濃度が適度になると、電解液貯留槽１５内の硫酸溶液の一部は送液ポンプ２３によって送液ライン２２を通じて送液される。送液ライン２２を流れる硫酸溶液は、脱気装置２４で脱気された後、洗浄槽２１に送液され、加熱器２５で適温（４０℃～９０℃）に加熱される。なお、送液される電解硫酸溶液が前記適温の液温を有していれば、加熱器２５による加熱を必ずしも要しない。 When the persulfuric acid concentration becomes moderate, a part of the sulfuric acid solution in the electrolytic solution storage tank 15 is fed through the liquid feeding line 22 by the liquid feeding pump 23. The sulfuric acid solution flowing through the liquid feed line 22 is deaerated by the deaerator 24, then sent to the washing tank 21, and heated to an appropriate temperature (40 ° C. to 90 ° C.) by the heater 25. If the electrolytic sulfuric acid solution to be fed has the appropriate liquid temperature, heating by the heater 25 is not necessarily required.
　さらに、洗浄槽２１では、超音波付与装置３０により２０ｋＨｚ以上５ＭＨｚ以下の超音波が付与される。具体的には、超音波振動子３２を動作させると、超音波は、外槽３１、伝搬液３３を通して洗浄槽２１に伝達され、さらに内部の洗浄液に超音波が付与されて洗浄効果が高められる。この状態で洗浄槽２１内に半導体材料１００が洗浄液に浸漬するように配置されていると、超音波作用が与えられた洗浄液によって半導体材料１００の表面に付着している硬化したレジストが効果的に除去される。特に洗浄液は、溶存ガス量が十分に低くなっており、超音波の作用が十分に得られる。半導体材料１００は収納可能な適宜数を一度に洗浄することができる。洗浄時間は、洗浄効果などに応じて適宜設定することができる。 Furthermore, in the cleaning tank 21, ultrasonic waves of 20 kHz or more and 5 MHz or less are applied by the ultrasonic wave applying device 30. Specifically, when the ultrasonic transducer 32 is operated, the ultrasonic wave is transmitted to the cleaning tank 21 through the outer tank 31 and the propagation liquid 33, and further, the ultrasonic wave is applied to the internal cleaning liquid to enhance the cleaning effect. . If the semiconductor material 100 is disposed in the cleaning tank 21 so as to be immersed in the cleaning liquid in this state, the cured resist attached to the surface of the semiconductor material 100 by the cleaning liquid to which the ultrasonic action is applied is effectively used. Removed. In particular, the amount of dissolved gas in the cleaning liquid is sufficiently low, and the action of ultrasonic waves is sufficiently obtained. An appropriate number of semiconductor materials 100 can be washed at a time. The cleaning time can be appropriately set according to the cleaning effect and the like.
　洗浄に際しては、送液ポンプ２３によって電解硫酸溶液を送液しつつ行ってもよい。この場合、過剰な洗浄液は、洗浄槽２１から排液され、排液ライン２６を通して冷却器２７で適温、例えば１０～９０℃に冷却されて電解液貯留槽１５に移動する。洗浄槽２１を電解液貯留槽１５よりも高い位置に設置しておけば、大気圧によって洗浄液は洗浄槽２１から電解液貯留槽１５へと移動する。大気圧による移動が不可の場合には、環流ポンプなどを排液ライン２６に設置して強制的に送液する。 The cleaning may be performed while feeding the electrolytic sulfuric acid solution by the liquid feeding pump 23. In this case, the excess cleaning liquid is drained from the cleaning tank 21, cooled to an appropriate temperature, for example, 10 to 90 ° C. by the cooler 27 through the drain line 26, and moved to the electrolyte storage tank 15. If the cleaning tank 21 is installed at a position higher than the electrolytic solution storage tank 15, the cleaning liquid moves from the cleaning tank 21 to the electrolytic solution storage tank 15 by atmospheric pressure. If movement by atmospheric pressure is impossible, a reflux pump or the like is installed in the drain line 26 to forcibly feed the liquid.
　電解液貯留槽１５に送られた洗浄液は、さらに、電解側循環ライン１２を通して循環ポンプ１３による送液、冷却器１４による冷却を受けて電解装置１０へと送液され、前記したように通液しつつ電解を行うことができる。これにより洗浄液は電解硫酸溶液として再生することができ、電解側循環ライン１２を通して電解、脱ガスが繰り返される。
　これらの動作により、電解硫酸溶液の過硫酸濃度を適当な範囲に維持しつつ洗浄に供することができる。なお、排液、電解、供給は、連続して行ってもよく、また、間欠的に行ってもよい。 The cleaning liquid sent to the electrolytic solution storage tank 15 is further fed by the circulation pump 13 through the electrolysis side circulation line 12 and cooled by the cooler 14 and is sent to the electrolysis apparatus 10, and is passed through as described above. However, electrolysis can be performed. As a result, the cleaning liquid can be regenerated as an electrolytic sulfuric acid solution, and electrolysis and degassing are repeated through the electrolytic side circulation line 12.
By these operations, the persulfuric acid concentration of the electrolytic sulfuric acid solution can be used for cleaning while maintaining it in an appropriate range. Note that drainage, electrolysis, and supply may be performed continuously or intermittently.
（実施形態２）
　次に、他の実施形態の洗浄装置１ａを図２、３に基づいて説明する。この形態は、洗浄部として枚葉式の洗浄機を備えるものである。なお、前記実施形態と同様の構成については同一の符号を付してその説明を省略または簡略化する。 (Embodiment 2)
Next, a cleaning apparatus 1a according to another embodiment will be described with reference to FIGS. In this embodiment, a single-wafer type washing machine is provided as a washing unit. In addition, the same code | symbol is attached | subjected about the structure similar to the said embodiment, and the description is abbreviate | omitted or simplified.
　洗浄装置１ａは、電解装置１０と、洗浄部４０とを備えている。
　電解装置１０は無隔膜型であり、少なくとも硫酸溶液と接液する部分をダイヤモンド電極とした陽極１１ａおよび陰極１１ｂが隔膜で隔てることなく内部に配置され、両電極には図示しない直流電源が接続されている。
　上記電解装置１０には、電解液貯留槽１５が電解側循環ライン１２を介して循環通液可能に接続され、送り側の電解側循環ライン１２には、硫酸溶液を循環させる循環ポンプ１３と冷却器１４とが順に介設されている。戻り側の電解側循環ライン１２には、気液分離器１６が介設されている。気液分離器１６は本発明の気液分離部に相当する。気液分離器１６としては重力や遠心力を利用したものにより構成することができるが本発明としては特定の構成に限定されない。 The cleaning device 1 a includes an electrolysis device 10 and a cleaning unit 40.
The electrolyzer 10 is a non-diaphragm type, and an anode 11a and a cathode 11b each having at least a portion in contact with a sulfuric acid solution as a diamond electrode are arranged inside without being separated by a diaphragm, and a DC power source (not shown) is connected to both electrodes. ing.
An electrolytic solution storage tank 15 is connected to the electrolysis apparatus 10 through an electrolysis-side circulation line 12 so as to be able to circulate, and the electrolysis-side circulation line 12 on the feed side is cooled with a circulation pump 13 for circulating a sulfuric acid solution. A container 14 is interposed in order. A gas-liquid separator 16 is interposed in the return-side electrolysis-side circulation line 12. The gas-liquid separator 16 corresponds to the gas-liquid separator of the present invention. The gas-liquid separator 16 can be configured by using gravity or centrifugal force, but the present invention is not limited to a specific configuration.
　電解液貯留槽１５には、送液ポンプ２３を介して送液ライン２２が接続されている。送液ライン２２は、本発明の洗浄液供給ラインに相当する。また、送液ライン２２には送液ポンプ２３の下流側に脱気装置２４が設けられている。脱気装置２４は、本発明の脱気部に相当する。脱気装置２４としては、脱気膜やアスピレーターなどにより構成することができるが、本発明としては特定の構成に限定されない。また、送液ライン２２には、脱気装置２４の下流側に加熱器２８が備えられており、例えば洗浄液を一過式で４０～９５℃の液温に加熱する。加熱器２８は、例えば石英製の管路を有し、近赤外線ヒータによって電解硫酸溶液を一過式で加熱する。 A liquid supply line 22 is connected to the electrolytic solution storage tank 15 via a liquid supply pump 23. The liquid feed line 22 corresponds to the cleaning liquid supply line of the present invention. Further, a degassing device 24 is provided in the liquid feed line 22 on the downstream side of the liquid feed pump 23. The deaeration device 24 corresponds to the deaeration unit of the present invention. The deaeration device 24 can be constituted by a deaeration membrane or an aspirator, but the present invention is not limited to a specific configuration. In addition, the liquid feed line 22 is provided with a heater 28 on the downstream side of the deaeration device 24, and for example, the cleaning liquid is heated to a liquid temperature of 40 to 95 ° C. in a transient manner. The heater 28 has a pipeline made of, for example, quartz, and heats the electrolytic sulfuric acid solution in a transient manner with a near infrared heater.
　送液ライン２２の送液先端側は、枚葉式の洗浄部４０のノズル４１に接続されている。
　ノズル４１は、図３に示すように、内部に超音波振動子３５が配置されており、ノズル４１内を流れる電解硫酸溶液に超音波が付与される。したがって、ノズル４１は、超音波付与装置としての機能も有している。
　枚葉式の洗浄部４０では、搬入された半導体材料１００に向けて前記ノズル４１が位置するようにノズル４１が設置されしており、ノズル４１から洗浄液としての電解硫酸溶液がスプレーされるか少量ずつ流下される。そのスプレー方向や流下方向には、半導体材料１００を載置して回転させる回転台４２を備える。 The liquid feed front end side of the liquid feed line 22 is connected to the nozzle 41 of the single wafer cleaning unit 40.
As shown in FIG. 3, the ultrasonic transducer 35 is disposed inside the nozzle 41, and ultrasonic waves are applied to the electrolytic sulfuric acid solution flowing through the nozzle 41. Therefore, the nozzle 41 also has a function as an ultrasonic wave imparting device.
In the single wafer cleaning unit 40, the nozzle 41 is installed so that the nozzle 41 is positioned toward the semiconductor material 100 carried in, and an electrolytic sulfuric acid solution as a cleaning solution is sprayed from the nozzle 41 or a small amount. It flows down one by one. In the spray direction and the flow-down direction, a turntable 42 for placing and rotating the semiconductor material 100 is provided.
　さらに、洗浄部４０には、洗浄液の廃棄ライン４３と、排液ライン４４とが接続されている。排液ライン４４には第１環流ポンプ４５が介設され、その下流側で排液ライン４４に、洗浄液を一時的に貯留する分解槽４６が介設されている。分解槽４６の下流側では、排液ライン４４にさらに第２環流ポンプ４７が介設され、その下流側で冷却器４８を介して排液ライン４４の下流端が電解液貯留槽１５に接続されている。 Furthermore, a cleaning liquid disposal line 43 and a drainage line 44 are connected to the cleaning unit 40. A first circulating pump 45 is interposed in the drainage line 44, and a decomposition tank 46 for temporarily storing the cleaning liquid is interposed in the drainage line 44 on the downstream side thereof. On the downstream side of the decomposition tank 46, a second circulating pump 47 is further provided in the drainage line 44, and on the downstream side thereof, the downstream end of the drainage line 44 is connected to the electrolyte storage tank 15 via the cooler 48. ing.
　次に、上記構成からなる洗浄装置の動作について説明する。
　この実施形態でも、高ドーズインプラがされた半導体材料１００を被洗浄材とし、回転台４２上に載置される。
　電解液貯留槽１５には、硫酸濃度７５～９６質量％（好適には８０～９２質量％）の硫酸溶液が貯留される。前記硫酸溶液は、循環ポンプ１３により電解側循環ライン１２を通じて送液され、冷却器１４で（電解装置１０内での温度が）１０～９０℃になるように冷却されて電解装置１０の入液側に導入される。 Next, the operation of the cleaning apparatus having the above configuration will be described.
Also in this embodiment, the semiconductor material 100 with high dose implantation is used as a material to be cleaned, and is placed on the turntable 42.
In the electrolytic solution storage tank 15, a sulfuric acid solution having a sulfuric acid concentration of 75 to 96% by mass (preferably 80 to 92% by mass) is stored. The sulfuric acid solution is fed through the electrolysis-side circulation line 12 by the circulation pump 13, cooled by the cooler 14 (temperature in the electrolysis apparatus 10) to 10 to 90 ° C., and then enters the electrolysis apparatus 10. Introduced on the side.
　電解装置１０では、直流電源によって陽極１１ａ、陰極１１ｂ間に電流密度が電極面積に対し１０～１０，０００Ａ／ｍ２となるように通電され、電解装置１０内に導入された硫酸溶液が電極面と並行方向に、１～１０，０００ｍ／ｈｒ．の線速で通液しつつ電解される。電解によって電解装置１０では、陽極１１ａ側で過硫酸を含む酸化性物質が生成される。酸化性物質は、前記硫酸溶液と混在した状態で電解装置１０外に送液され、気液分離器１６で気液分離された後、電解側循環ライン１２を通じて電解液貯留槽１５に返送される。硫酸溶液は、電解側循環ライン１２を通じて、電解液貯留槽１５に戻された後、繰り返し電解装置１０に送られ、電解により過硫酸の濃度が高められる。過硫酸濃度としては、例えばペルオキソ二硫酸の単位で２～２０ｇ　ａｓ　Ｓ２Ｏ８ ２－ ／Ｌが挙げられる。
In the electrolyzer 10, a DC power source is energized between the anode 11a and the cathode 11b so that the current density is 10 to 10,000 A / m 2 with respect to the electrode area, and the sulfuric acid solution introduced into the electrolyzer 10 is the electrode surface. 1 to 10,000 m / hr. Electrolysis is performed while passing the liquid at a linear speed of. In the electrolysis apparatus 10, an oxidizing substance containing persulfuric acid is generated on the anode 11a side by electrolysis. The oxidizing substance is sent to the outside of the electrolysis apparatus 10 in a state of being mixed with the sulfuric acid solution, separated into gas and liquid by the gas / liquid separator 16, and then returned to the electrolyte storage tank 15 through the electrolysis side circulation line 12. . The sulfuric acid solution is returned to the electrolytic solution storage tank 15 through the electrolytic side circulation line 12, and then repeatedly sent to the electrolytic device 10, where the concentration of persulfuric acid is increased by electrolysis. Examples of the persulfuric acid concentration include 2 to 20 g as S 2 O 8 2− / L in units of peroxodisulfuric acid.
　過硫酸濃度が適度になると、電解液貯留槽１５内の硫酸溶液の一部は送液ポンプ２３によって送液ライン２２を通じて送液される。送液ライン２２を流れる硫酸溶液は、脱気装置２４で脱気された後、加熱器２８で４０～９５℃に加熱されて洗浄部４０に送液される。なお、送液される電解硫酸溶液が前記適温の液温を有していれば、加熱器２８による加熱を必ずしも要しない。 When the persulfuric acid concentration becomes moderate, a part of the sulfuric acid solution in the electrolytic solution storage tank 15 is fed through the liquid feeding line 22 by the liquid feeding pump 23. The sulfuric acid solution flowing through the liquid feed line 22 is deaerated by the deaerator 24, heated to 40 to 95 ° C. by the heater 28, and sent to the cleaning unit 40. If the electrolytic sulfuric acid solution to be fed has the appropriate liquid temperature, heating by the heater 28 is not necessarily required.
　洗浄部４０では、ノズル４１に電解硫酸溶液が送液され、ノズル４１内で超音波振動子３５の動作により２０ｋＨｚ以上５ＭＨｚ以下の超音波がノズル４１内を流れる電解硫酸溶液に付与される。この状態で回転台４２を回転させつつ回転台４２上の半導体材料１００に電解硫酸溶液が洗浄液としてスプレー又は流下によって接触し、超音波作用が与えられた洗浄液によって半導体材料１００の表面に付着している硬化したレジストが効果的に除去される。洗浄時間は、洗浄効果などに応じて適宜設定することができる。 In the cleaning unit 40, the electrolytic sulfuric acid solution is sent to the nozzle 41, and ultrasonic waves of 20 kHz to 5 MHz are applied to the electrolytic sulfuric acid solution flowing in the nozzle 41 by the operation of the ultrasonic vibrator 35 in the nozzle 41. In this state, while rotating the turntable 42, the electrolytic sulfuric acid solution comes into contact with the semiconductor material 100 on the turntable 42 as a cleaning liquid by spraying or flowing down, and adheres to the surface of the semiconductor material 100 by the cleaning liquid provided with ultrasonic action. The cured resist that is present is effectively removed. The cleaning time can be appropriately set according to the cleaning effect and the like.
　洗浄に使用された洗浄液は、洗浄部４０の本体内を次第に流れ落ちて廃棄ライン４３、排液ライン４４で取り出される。廃棄ライン４３は、適宜時機に図示しない開閉弁を開放するなどして不要な洗浄液を系外に廃棄することができる。常時には、排液ライン４４から取り出された洗浄液は、第１環流ポンプ４５で分解槽４６に一時貯留され、半導体材料１００から除去されたレジスト等の分解処理を行う。一時貯留時間は適宜設定することができる。分解槽４６で一時貯留された洗浄液は、さらに下流側の排液ライン４４を通して第２循環ポンプ４７で送液され、冷却器４８で適温、例えば１０～９０℃に冷却されて電解液貯留槽１５に送られる。 The cleaning liquid used for the cleaning gradually flows down in the main body of the cleaning unit 40 and is taken out by the waste line 43 and the drain line 44. The disposal line 43 can dispose of unnecessary cleaning liquid outside the system by opening an on-off valve (not shown) as needed. At all times, the cleaning liquid taken out from the drainage line 44 is temporarily stored in the decomposition tank 46 by the first recirculation pump 45 and decomposes the resist removed from the semiconductor material 100. The temporary storage time can be set as appropriate. The cleaning solution temporarily stored in the decomposition tank 46 is further sent by the second circulation pump 47 through the drainage line 44 on the downstream side, and cooled to an appropriate temperature, for example, 10 to 90 ° C. by the cooler 48, and is stored in the electrolyte storage tank 15. Sent to.
　電解液貯留槽１５に送られた洗浄液は、さらに、電解側循環ライン１２を通して循環ポンプ１３による送液、冷却器１４による冷却を受けて電解装置１０へと送液され、前記したように通液しつつ電解を行うことができる。これにより洗浄液は電解硫酸溶液として再生することができ、電解側循環ライン１２を通して電解、脱ガスが繰り返される。
　これらの動作により、電解硫酸溶液の過硫酸濃度を適当な範囲に維持しつつ洗浄に供することができる。 The cleaning liquid sent to the electrolytic solution storage tank 15 is further fed by the circulation pump 13 through the electrolysis side circulation line 12 and cooled by the cooler 14 and is sent to the electrolysis apparatus 10, and is passed through as described above. However, electrolysis can be performed. As a result, the cleaning liquid can be regenerated as an electrolytic sulfuric acid solution, and electrolysis and degassing are repeated through the electrolytic side circulation line 12.
By these operations, the persulfuric acid concentration of the electrolytic sulfuric acid solution can be used for cleaning while maintaining it in an appropriate range.
　硫酸を電解して生成した電解液を用い、以下の方法により酸化剤の活性化試験、硬化レジストの剥離試験を行った。
〔酸化剤の活性化試験〕
１）処理溶液
・実施例：８５％硫酸を電流密度０．５　Ａ／ｃｍ２で電解した電解硫酸溶液
　（過硫酸濃度　１０ｇ　ａｓ　Ｓ２Ｏ８ ２－／Ｌ）
・比較例：ＳＰＭ（硫酸：過酸化水素＝５：１、硫酸濃度８５％相当） Using an electrolytic solution generated by electrolyzing sulfuric acid, an oxidizing agent activation test and a cured resist peeling test were performed by the following methods.
[Activation test of oxidizing agent]
1) Treatment solution / Example: electrolytic sulfuric acid solution obtained by electrolyzing 85% sulfuric acid at a current density of 0.5 A / cm 2 (persulfuric acid concentration 10 g as S 2 O 8 2− / L)
Comparative example: SPM (sulfuric acid: hydrogen peroxide = 5: 1, sulfuric acid concentration equivalent to 85%)
２）試験条件
・実施例：電解硫酸溶液の温度を２０、４０、６０、８０℃に設定し、２８、４５、１００、７５０ｋＨｚの超音波を３０分照射した。
・比較例：ＳＰＭを６０℃に設定し、４５ｋＨｚの超音波を３０分照射した。
　実施例、比較例ともに、超音波照射前後の酸化剤濃度をヨウ化カリウムで滴定測定し、活性化の有無を判断した。 2) Test conditions / Examples: The temperature of the electrolytic sulfuric acid solution was set to 20, 40, 60, and 80 ° C., and ultrasonic waves of 28, 45, 100, and 750 kHz were irradiated for 30 minutes.
-Comparative example: SPM was set to 60 degreeC and the 45-kHz ultrasonic wave was irradiated for 30 minutes.
In both Examples and Comparative Examples, the oxidant concentration before and after ultrasonic irradiation was titrated with potassium iodide to determine the presence or absence of activation.
３）試験結果
　試験結果を表１に示す。表１は電解硫酸溶液を３０分処理した時の酸化剤分解率（％）を示す。
　実施例では液温を４０℃以上とすることで、酸化剤濃度が低下しており、活性化していることが分かる。いずれの条件においても酸化剤は分解しなかった。
　一方、ＳＰＭの分解率は５％未満であり殆ど分解しなかった。 3) Test results Table 1 shows the test results. Table 1 shows the oxidant decomposition rate (%) when the electrolytic sulfuric acid solution was treated for 30 minutes.
In the examples, it can be seen that when the liquid temperature is set to 40 ° C. or higher, the oxidant concentration is lowered and activated. Under any condition, the oxidizing agent was not decomposed.
On the other hand, the decomposition rate of SPM was less than 5% and hardly decomposed.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
〔硬化レジスト剥離試験〕
１）供試サンプル
・有機レジストを塗布したＳｉウェハにＥ１６（ａｔｏｍｓ／ｃｍ２）のドーズ量でドーズをインプラしたもの [Hardened resist peeling test]
1) Sample sample / Si wafer coated with organic resist, dose implanted at a dose of E16 (atoms / cm 2 )
２）処理溶液
・実施例：８５％硫酸を電流密度０．５　Ａ／ｃｍ２で電解した電解硫酸溶液
　（過硫酸濃度　１０ｇ　ａｓ　Ｓ２Ｏ８ ２－／Ｌ）
・比較例：ＳＰＭ（硫酸：過酸化水素＝５：１、硫酸濃度８５％相当） 2) Treatment Solution / Example: Electrolytic sulfuric acid solution obtained by electrolyzing 85% sulfuric acid at a current density of 0.5 A / cm 2 (persulfuric acid concentration 10 g as S 2 O 8 2− / L)
Comparative example: SPM (sulfuric acid: hydrogen peroxide = 5: 1, sulfuric acid concentration equivalent to 85%)
３）試験条件
・実施例：液温を６０、８０℃に設定し、処理溶液にＳｉウェハを浸漬させ、２８、４５、１００、７５０ｋＨｚの超音波を１０分照射した。
・比較例：液温を６０℃に設定し、Ｓｉウェハを浸漬させ、４５ｋＨｚの超音波で１０分照射した。 3) Test conditions and examples: The liquid temperature was set to 60 and 80 ° C., the Si wafer was immersed in the treatment solution, and ultrasonic waves of 28, 45, 100 and 750 kHz were irradiated for 10 minutes.
Comparative Example: The liquid temperature was set to 60 ° C., the Si wafer was immersed, and irradiated with 45 kHz ultrasonic waves for 10 minutes.
４）試験結果
・試験後のＳｉウェハ顕微鏡写真（表面のレーザ顕微鏡写真　倍率５００倍）を図４（ａ）（ｂ）に示す。
　図４（ａ）は、実施例であり、液温６０℃、超音波４５ｋＨｚで試験したものであり、図４（ｂ）は、比較例であり、液温６０℃、超音波４５ｋＨｚで試験したものである。
　実施例ではいずれの条件でもレジストが完全剥離したが、比較例ではレジストが剥離しきれず一部残留した。 4) Test results and post-test Si wafer micrographs (surface laser micrograph magnification 500 times) are shown in FIGS. 4 (a) and 4 (b).
FIG. 4A is an example, which was tested at a liquid temperature of 60 ° C. and an ultrasonic wave of 45 kHz, and FIG. 4B was a comparative example, which was tested at a liquid temperature of 60 ° C. and an ultrasonic wave of 45 kHz. Is.
In the examples, the resist was completely peeled off under any condition, but in the comparative example, the resist was not completely peeled off and partly remained.
　以上、本発明について上記実施形態及び実施例に基づいて説明を行ったが、本発明は上記説明に限定されるものではなく、本発明を逸脱しない限りは適宜の変更が可能である。 As mentioned above, although this invention was demonstrated based on the said embodiment and Example, this invention is not limited to the said description, As long as it does not deviate from this invention, an appropriate change is possible.
　１　　洗浄装置
　１ａ　洗浄装置
１０　　電解装置
１１ａ　陽極
１１ｂ　陰極
１５　　電解液貯留槽
１６　　気液分離器
２０　　洗浄部
２１　　洗浄槽
２２　　送液ライン
２４　　脱気部
２５　　加熱器
３０　　超音波付与装置
３２　　超音波振動子
３５　　超音波振動子
４０　　洗浄部
４１　　ノズル
１００　半導体材料 DESCRIPTION OF SYMBOLS 1 Cleaning apparatus 1a Cleaning apparatus 10 Electrolytic apparatus 11a Anode 11b Cathode 15 Electrolyte storage tank 16 Gas-liquid separator 20 Cleaning part 21 Cleaning tank 22 Liquid feed line 24 Deaeration part 25 Heater 30 Ultrasonic applicator 32 Ultrasonic vibrator 35 Ultrasonic vibrator 40 Cleaning unit 41 Nozzle 100 Semiconductor material

Claims (13)

  1. 　硫酸溶液を電気分解し生成した電解硫酸溶液に超音波を付与し、前記超音波を付与した前記電解硫酸溶液で被洗浄材の表面洗浄を行うことを特徴とする洗浄方法。 A cleaning method comprising applying ultrasonic waves to an electrolytic sulfuric acid solution generated by electrolyzing a sulfuric acid solution, and cleaning the surface of the material to be cleaned with the electrolytic sulfuric acid solution applied with the ultrasonic waves.
  2. 　前記洗浄に用いる前記電解硫酸溶液の温度が４０℃以上であることを特徴とする請求項１記載の洗浄方法。 The cleaning method according to claim 1, wherein the temperature of the electrolytic sulfuric acid solution used for the cleaning is 40 ° C or higher.
  3. 　前記洗浄に用いる前記電解硫酸溶液の温度が９５℃以下であることを特徴とする請求項１または２に記載の洗浄方法。 The cleaning method according to claim 1 or 2, wherein the temperature of the electrolytic sulfuric acid solution used for the cleaning is 95 ° C or lower.
  4. 　前記超音波の周波数を２０ｋＨｚ～５ＭＨｚとすることを特徴とする請求項１～３のいずれかに記載の洗浄方法。 The cleaning method according to any one of claims 1 to 3, wherein the frequency of the ultrasonic wave is 20 kHz to 5 MHz.
  5. 　前記被洗浄材がレジストが付着した電子材料であることを特徴とする請求項１～４のいずれかに記載の洗浄方法。 5. The cleaning method according to claim 1, wherein the material to be cleaned is an electronic material to which a resist is attached.
  6. 　前記電解硫酸溶液に前記超音波を付与する前に、前記電解硫酸溶液の気液分離を行うことを特徴とする請求項１～５のいずれかに記載の洗浄方法。 6. The cleaning method according to claim 1, wherein the electrolytic sulfuric acid solution is subjected to gas-liquid separation before applying the ultrasonic wave to the electrolytic sulfuric acid solution.
  7. 　前記気液分離をした後、前記電解硫酸溶液に超音波を付与する前に、前記電解硫酸溶液の脱気処理を行うことを特徴とする請求項６に記載の洗浄方法。 The cleaning method according to claim 6, wherein after the gas-liquid separation, the electrolytic sulfuric acid solution is degassed before applying ultrasonic waves to the electrolytic sulfuric acid solution.
  8. 　硫酸溶液を電解する電解装置と、
    　前記電解装置で電解されて生成された電解硫酸溶液を洗浄液として被洗浄材を洗浄する洗浄部と、
    　前記電解装置で電解された電解硫酸溶液を前記洗浄部に供給する洗浄液供給ラインと、
    　前記洗浄部で使用される前記電解硫酸溶液に超音波を付与する超音波付与装置と、を備えることを特徴とする洗浄装置。     An electrolyzer for electrolyzing a sulfuric acid solution;
    A cleaning section for cleaning the material to be cleaned using an electrolytic sulfuric acid solution generated by electrolysis in the electrolysis apparatus as a cleaning liquid;
    A cleaning liquid supply line for supplying an electrolytic sulfuric acid solution electrolyzed by the electrolytic device to the cleaning unit;
    An ultrasonic application device that applies ultrasonic waves to the electrolytic sulfuric acid solution used in the cleaning unit.
  9. 　前記超音波付与の前に前記電解硫酸溶液の気液分離を行う気液分離部をさらに備えることを特徴とする請求項８記載の洗浄装置。 The cleaning apparatus according to claim 8, further comprising a gas-liquid separation unit that performs gas-liquid separation of the electrolytic sulfuric acid solution before applying the ultrasonic wave.
  10. 　前記気液分離部の後に前記超音波付与の前に前記電解硫酸溶液の脱気を行う脱気部を備えることを特徴とする請求項９記載の洗浄装置。 The cleaning apparatus according to claim 9, further comprising a deaeration unit that deaerates the electrolytic sulfuric acid solution after the gas-liquid separation unit and before applying the ultrasonic wave.
  11. 　さらに、前記洗浄部で用いられる前記電解硫酸溶液を加熱する加熱部を備えることを特徴とする請求項８～１０のいずれかに記載の洗浄装置。 11. The cleaning apparatus according to claim 8, further comprising a heating unit that heats the electrolytic sulfuric acid solution used in the cleaning unit.
  12. 　前記洗浄部が、１または２以上の被洗浄材を洗浄槽の洗浄液に浸漬して洗浄するバッチ式であり、前記超音波付与装置は、前記洗浄槽に超音波を伝播させるものであることを特徴とする請求項８～１１のいずれかに記載の洗浄装置。 The cleaning unit is a batch type in which one or two or more materials to be cleaned are immersed in a cleaning liquid in a cleaning tank for cleaning, and the ultrasonic wave imparting device propagates ultrasonic waves to the cleaning tank. The cleaning device according to any one of claims 8 to 11, wherein
  13. 　前記洗浄部が、１または２以上の被洗浄材に洗浄液を送液しつつ接触させて洗浄する枚葉式であり、前記超音波付与装置は、前記洗浄液を前記被洗浄材に向けて送液するノズル内で前記被洗浄材に前記超音波を伝播させるものであることを特徴とする請求項８～１１のいずれかに記載の洗浄装置。 The cleaning unit is a single-wafer type in which cleaning liquid is brought into contact with one or more materials to be cleaned while being brought into contact with the cleaning material, and the ultrasonic wave applicator supplies the cleaning liquid toward the material to be cleaned. The cleaning apparatus according to any one of claims 8 to 11, wherein the ultrasonic wave is propagated through the nozzle to be cleaned to the material to be cleaned.
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CN116936348B (en) * 2023-09-07 2024-01-30 浙江晶越半导体有限公司 Wafer surface cleaning method

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