WO1999051796A1 - Method for removing photoresist and plasma etch residues - Google Patents

Method for removing photoresist and plasma etch residues Download PDF

Info

Publication number
WO1999051796A1
WO1999051796A1 PCT/US1998/006907 US9806907W WO9951796A1 WO 1999051796 A1 WO1999051796 A1 WO 1999051796A1 US 9806907 W US9806907 W US 9806907W WO 9951796 A1 WO9951796 A1 WO 9951796A1
Authority
WO
WIPO (PCT)
Prior art keywords
cleaning composition
hydroxylammonium
substrate
group
water
Prior art date
Application number
PCT/US1998/006907
Other languages
French (fr)
Inventor
Vincent G. Leon
Kenji Honda
Eugene F. Rothgery
Original Assignee
Olin Microelectronic Chemicals, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Olin Microelectronic Chemicals, Inc. filed Critical Olin Microelectronic Chemicals, Inc.
Priority to JP2000542506A priority Critical patent/JP2002510752A/en
Priority to EP98915347A priority patent/EP1070157A4/en
Priority to KR1020007011074A priority patent/KR20010042461A/en
Priority to PCT/US1998/006907 priority patent/WO1999051796A1/en
Priority to AU69556/98A priority patent/AU6955698A/en
Publication of WO1999051796A1 publication Critical patent/WO1999051796A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
    • 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
    • H01L21/02041—Cleaning
    • H01L21/02057—Cleaning during device manufacture
    • H01L21/02068—Cleaning during device manufacture during, before or after processing of conductive layers, e.g. polysilicon or amorphous silicon layers
    • H01L21/02071—Cleaning during device manufacture during, before or after processing of conductive layers, e.g. polysilicon or amorphous silicon layers the processing being a delineation, e.g. RIE, of conductive layers
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
    • C11D3/39—Organic or inorganic per-compounds
    • C11D3/3942—Inorganic per-compounds
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
    • C11D7/02—Inorganic compounds
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
    • C11D7/02—Inorganic compounds
    • C11D7/04—Water-soluble compounds
    • C11D7/06—Hydroxides
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
    • C11D7/02—Inorganic compounds
    • C11D7/04—Water-soluble compounds
    • C11D7/08—Acids
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
    • C11D7/02—Inorganic compounds
    • C11D7/04—Water-soluble compounds
    • C11D7/10—Salts
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
    • C23G1/04—Cleaning or pickling metallic material with solutions or molten salts with acid solutions using inhibitors
    • C23G1/06—Cleaning or pickling metallic material with solutions or molten salts with acid solutions using inhibitors organic inhibitors
    • C23G1/061—Cleaning or pickling metallic material with solutions or molten salts with acid solutions using inhibitors organic inhibitors nitrogen-containing compounds
    • 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
    • G03F7/422—Stripping or agents therefor using liquids only
    • G03F7/425—Stripping or agents therefor using liquids only containing mineral alkaline compounds; containing organic basic compounds, e.g. quaternary ammonium compounds; containing heterocyclic basic compounds containing nitrogen
    • 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
    • H01L21/31105—Etching inorganic layers
    • H01L21/31111—Etching inorganic layers by chemical means
    • H01L21/31116—Etching inorganic layers by chemical means by dry-etching
    • C11D2111/22—

Definitions

  • This invention relates to a cleaning method for use in microelectronics manufacturing, and more particularly to a non-corrosive method for removing photoresist and plasma etch residues formed on wafer substrates after plasma etching of metal layers or oxide layers deposited on the substrates.
  • positive photoresists are used as an intermediate mask for transferring an original mask pattern of a reticule onto wafer substrates by means of a series of photolithography and plasma etching steps.
  • One of the final steps in the microcircuit manufacturing process is the removal of the patterned photoresist films from the substrates. In general, this step is affected by one of two methods.
  • One method involves a wet stripping step in which the photoresist-covered substrate is brought into contact with a photoresist stripper solution that consists primarily of an organic solvent and an amine.
  • stripper solutions cannot completely and reliably remove the photoresist films, especially if the photoresist films have been exposed to UV radiation and plasma treatments during fabrication.
  • An alternative method of removing a photoresist film involves exposing a photoresist-coated wafer to oxygen plasma in order to burn the resist film from the substrate surface in a process known as oxygen plasma ashing.
  • Oxygen plasma ashing has become more popular in the microcircuit manufacturing process because it is carried out in a vacuum chamber and, hence, is expected to be less susceptible to airborne particulate or metallic contamination.
  • EKC 265 available from EKC Technology, Inc.
  • ACT 935 available from Ashland Chemical
  • R-10 a post-strip rinse available from Mitsubishi Gas Chemical, is composed of water, alkanolamine and a sugar alcohol, wherein the sugar alcohol acts as a corrosion inhibitor.
  • Japanese Patent Application No. 7-028254 assigned to Kanto Kagaku, discloses a non-corrosive resist removal liquid comprising a sugar alcohol, an alcohol amine, water, and a quaternary ammonium hydroxide.
  • PCT Published Patent Application No. WO 88-05813 teaches a positive or negative photoresist stripper containing butyrolactone or caprolactone, quaternary ammonium hydroxide compound, and optionally, a nonionic surfactant.
  • U.S. Patent No. 4,239,661 to Muraoka et al. discloses a surface-treating agent comprising an aqueous solution of 0.01 % to 20% trialkyl (hydroxyalkyl) ammonium hydroxide. This agent is useful in removing organic and inorganic contaminants deposited on the surface of intermediate semiconductor products.
  • U.S. Patent No. 4,904,571 to Miyashita et al. teaches printed circuit board photoresist stripper composition containing a solvent (e.g., water, alcohols, ethers, ketones, and the like), an alkaline compound dissolved in the solvent, including quaternary ammonium hydroxide, and a borohydride compound dissolved in the solvent.
  • a solvent e.g., water, alcohols, ethers, ketones, and the like
  • an alkaline compound dissolved in the solvent including quaternary ammonium hydroxide, and a borohydride compound dissolved in the solvent.
  • U.S. Patent No. 5,091,103 to Dean et al. teaches a positive photoresist stripping composition containing: (A) N-alkyl-2-pyrrolidone; (B) 1,2-propanediol; and (C) tetraalkylammonium hydroxide.
  • U.S. Patent No. 5,139,607 to Ward et al. teaches positive and negative photoresist stripping composition containing: (A) tetrahydrofurfuryl alcohol; (B) a polyhydric alcohol (e.g., ethylene glycol or propylene glycol); (C) the reaction product of furfuryl alcohol and an alkylene oxide; (D) a water-soluble Bronstead base type hydroxide compound (e.g., alkali metal hydroxide, ammonium hydroxide and tetramethyl ammonium hydroxide); and (E) water.
  • the composition may also contain up to 1% of a nonionic surfactant.
  • U.S. Patent No. 5,174,816 to Aoyama et al. discloses a composition for removing chlorine remaining on the surface of an aluminum line pattern substrate after dry etching, which composition comprises an aqueous solution containing 0.01 to 15% by weight of a quaternary ammonium hydroxide, such as trimethyl (2-hydroxyethyl) ammonium hydroxide, and 0.1 to 20% by weight of sugar or sugar alcohol, such as xylitol, mannose, glucose and the like.
  • a quaternary ammonium hydroxide such as trimethyl (2-hydroxyethyl) ammonium hydroxide
  • sugar or sugar alcohol such as xylitol, mannose, glucose and the like.
  • compositions used to strip photoresist include a solution of H 2 SO and an oxidizing agent such as H 2 O 2 that oxidizes, and thus decomposes organic photoresists.
  • solutions containing strong acids and oxidizing agents are hazardous to handle, must be applied at elevated temperatures, and require a hot deionized (Dl) water rinse to prevent sulfates from crystallizing on the substrate.
  • Dl hot deionized
  • such solutions have a short active life as the oxidizing agent readily decomposes. Thus, it is necessary to frequently replenish the solutions. The need for solution replenishment renders the process both hazardous and economically inefficient.
  • the present invention is directed to a non-corrosive cleaning method useful for removing photoresist and plasma etch residues from a substrate.
  • the method comprises the steps of: (i) contacting the substrate with an aqueous based cleaning composition having a substantially neutral or mildly acidic pH; and (ii) rinsing the substrate with ozonated water.
  • the substrate is contacted with an aqueous-based cleaning composition having a substantially neutral or slightly acidic pH.
  • aqueous-based cleaning composition having a substantially neutral or slightly acidic pH.
  • One particularly suitable cleaning composition is Microstrip 5002, commercially available from Olin Microelectronic Materials. This stripping solution is described in copending U.S. Patent Application Serial No. 08/709,053, allowed February 20, 1998, the subject matter of which is incorporated herein by reference, and comprises (a) water; (b) at least one hydroxylammonium compound selected from the group consisting of hydroxylammonium salts of the formula (I):
  • Rj, R 2 and R 3 are individually selected from hydrogen, lower alkyl groups having 1 to 4 carbon atoms, lower alkoxy groups having 1 to 4 carbon atoms, hydroxyl and hydroxyl-substituted lower alkyl groups having 1 to 4 carbon atoms, with the proviso that at least two of R 1; R 2 and R 3 are either hydrogen, lower alkyl group or lower alkoxy group, and wherein X is an anionic moiety that is soluble in water and compatible with said quaternary ammonium hydroxide radical; and n is the valence of X and is from 1 to 3; and
  • the amount of acidic hydroxylammonium compound relative to the amount of basic amine and/or quaternary ammonium hydroxide is adjusted such that the pH of the overall composition is maintained within the range of about 2 to about 6, preferably within a range from about 2 to about 4.
  • the acidic hydroxylammonium compound inhibits metal attack. Due to the corrosion inhibiting action of acidic component, and the substantially neutral, or only mildly acidic pH, such compositions can be used in the absence of an additional corrosion inhibiting component.
  • Acidic hydroxylammonium compounds that can be used to form cleaning composition suitable for use with the cleaning method of the invention include hydroxylammonium salts such as hydroxylammonium nitrate (also referred to as HAN) , hydroxylammonium sulfate (also referred to as HAS), hydroxylammonium phosphate, hydroxylammoniun chloride, hydroxylammonium oxalate, hydroxylammonium citrate, hydroxylammonium fluoride, hydroxylammonium chloride, and the like.
  • Alkyl-substituted derivatives of hydroxylammonium salts are also useful: e.g. hydroxyl diethylammonium salts and the like.
  • the hydroxylammonium compound is present in the composition of the invention in the range of about 1% to about 70% by weight.
  • Amines that can be used as the basic component of cleaning compositions useful in the practice of the cleaning method of the invention include hydroxylamine and other alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, diethylene-glycolamine, N- hydroxylethylpiperazine, and the like.
  • Quaternary ammonium hydroxides that can be used as the basic component of cleaning compositions suitable for use in the practice of the cleaning method of the invention include tetraalkylammonium hydroxides having methyl, ethyl, propyl, butyl, hydroxyethyl, and the combinations thereof (e.g., tetramethylammonium hydroxide (hereinafter referred to as TMAH), tetraethyl-ammonium hydroxide, trimethyl hydroxyethylammonium hydroxide, methyl tri (hydroxyethyl) ammonium hydroxide, tetra (hydroxyethyl) ammonium hydroxide, benzyl trimethylammonium hydroxide and the like).
  • TMAH tetramethylammonium hydroxide
  • TMAH tetraethyl-ammonium hydroxide
  • trimethyl hydroxyethylammonium hydroxide methyl tri (hydroxyethyl) ammonium
  • a combination of ammonium hydroxide with one or more quaternary ammonium hydroxides may also be used.
  • the basic compound is present in the cleaning composition of the invention in the range of about 0.01% to about 10% by weight.
  • the balance of cleaning composition can comprise substantially of water.
  • a chelating stabilizer may be optionally included in the cleaning composition to stabilize the hydroxylammonium salts.
  • Suitable chelating stabilizers include triethylenetetramine (hereinafter referred to as TETA); 2,2'- [[methyl-lH-benzotriazol-l-yl)methyl]imino]bisethanol (Tradename is IRGAMET 42), (2-benzothiazolythio)succinic acid (Tradename is IRGACOR 252), tricine, bicine, and other water-soluble chelating compounds.
  • TETA triethylenetetramine
  • 2,2'- [[methyl-lH-benzotriazol-l-yl)methyl]imino]bisethanol Tradename is IRGAMET 42
  • (2-benzothiazolythio)succinic acid (Tradename is IRGACOR 252)
  • tricine, bicine and other water-soluble chelating compounds.
  • the stabilizer is present in the composition of the invention in the range of
  • a surfactant may also be optionally included in the cleaning composition so as to enhance the power of the plasma etching residue removal from the substrate.
  • Suitable surfactants are selected from nonionic types, cationic types and anionic types of surfactants.
  • a surfactant is present in the composition of the invention in the range of about 0.1 ppm to about 100 ppm by weight to a total weight of the cleaning composition.
  • the cleaning composition may also, optionally, contain a minor amount of a corrosion inhibitor such as sugar alcohols, catechol and the like.
  • the substrate can be contacted with the cleaning composition by any suitable method, such as by placing the cleaning composition into a tank and submerging the substrates into the cleaning composition.
  • the substrates are spray rinsed with the cleaning composition.
  • the substrates can then be contacted with the ozonated water using any suitable method, such as by placing the ozonated water into a tank where the substrates can be submerged into the water.
  • the substrates previously contacted with the cleaning composition are rinsed with the ozonated water using a spray rinse.
  • the ozonated water can be a simple mixture of ozone and ultra-pure water, e.g., Dl water.
  • the ozone can be generated by any conventional means, e.g., an ozone generator.
  • the mixing of the ozone and water may be achieved by any suitable method, such as jetting the ozone into the water by a gas feed nozzle; feeding the water and ozone into a spiral mixer; aspirating the gas into the flow of water; and feeding the ozone into a treatment tank regulated at a given pressure so that ozone is dissolved into the water.
  • the cleaning method of the present invention can also be used in combination with a dry stripping process. Dry stripping is typically conducted prior to the present cleaning method. Any suitable dry stripping process can be used including O 2 plasma ashing, ozone gas phase-treatment, fluorine plasma treatment, hot H 2 gas treatment (described in U.S. Pat. No. 5,691 ,117), and the like.
  • the preferred dry stripping process is O 2 plasma ashing.
  • the cleaning method can also be used in combination with a organic wet stripping method.
  • the organic wet strip can be performed either before, after, or both before and after the cleaning method of the present invention. Any conventional organic wet stripping solution can be used and a person skilled in the art would be able to choose the appropriate organic wet stripper.
  • the cleaning method of the invention can be used to replace the organic solvent-based post-strip rinse. Because the preferred cleaning composition is a non-corrosive and neutral to weakly acidic aqueous solution and 10
  • the cleaning compositions used in the present cleaning method may be disposed of in a regular drain system for aqueous chemical wastes.

Abstract

A method for the removing of plasma etch residues on a substrate comprising the steps of: (i) contacting the substrate with a cleaning composition, and (ii) contacting the substrate with ozonated water. The preferred cleaning composition has a pH from 2 to 6 and comprises: (A) water; (B) at least one selected hydroxylammonium compound; and (C) at least one basic compound; and optionally (D) a chelating stabilizer; and optionally (E) a surfactant.

Description

METHOD FOR REMOVING PHOTORESIST AND PLASMA ETCH
RESIDUES
BACKGROUND OF THE INVENTION
Field of The Invention
This invention relates to a cleaning method for use in microelectronics manufacturing, and more particularly to a non-corrosive method for removing photoresist and plasma etch residues formed on wafer substrates after plasma etching of metal layers or oxide layers deposited on the substrates.
Brief Description of Art
In the manufacture of microcircuits, positive photoresists are used as an intermediate mask for transferring an original mask pattern of a reticule onto wafer substrates by means of a series of photolithography and plasma etching steps. One of the final steps in the microcircuit manufacturing process is the removal of the patterned photoresist films from the substrates. In general, this step is affected by one of two methods. One method involves a wet stripping step in which the photoresist-covered substrate is brought into contact with a photoresist stripper solution that consists primarily of an organic solvent and an amine. However, stripper solutions cannot completely and reliably remove the photoresist films, especially if the photoresist films have been exposed to UV radiation and plasma treatments during fabrication. Some photoresist films become highly crosslinked by such treatments and are more difficult to dissolve in the stripper solution. In addition, the chemicals used in these conventional wet stripping methods are sometimes ineffective for removing inorganic residual materials formed during the plasma etching of metal or oxide layers with halogen- containing gases. An alternative method of removing a photoresist film involves exposing a photoresist-coated wafer to oxygen plasma in order to burn the resist film from the substrate surface in a process known as oxygen plasma ashing. Oxygen plasma ashing has become more popular in the microcircuit manufacturing process because it is carried out in a vacuum chamber and, hence, is expected to be less susceptible to airborne particulate or metallic contamination. However, oxygen plasma ashing is also not fully effective in removing plasma etching residues noted above. Instead, removal of these plasma etching residues must be accomplished by subsequently exposing the photoresist film to certain alkaline solutions. Several commercial products are now available to clean the plasma etching residues left by plasma etching followed by oxygen ashing. For example, EKC 265, available from EKC Technology, Inc., is a plasma etching cleaning solution composed of water, alkanolamine, catechol and hydroxylamine Such a composition is disclosed in U.S. Patent No. 5,279,771 to Lee. ACT 935, available from Ashland Chemical, is another plasma etching cleaning solution and is composed of water, alkanolamine and hydroxylamine. In both cases, hydroxylamine is used as a corrosion inhibitor. R-10, a post-strip rinse available from Mitsubishi Gas Chemical, is composed of water, alkanolamine and a sugar alcohol, wherein the sugar alcohol acts as a corrosion inhibitor.
Although these commercial products can effectively dissolve plasma etching residues, the combination of water and alkanolamine contained therein can also attack the metallic layers deposited patternwise on the substrate. The addition of a corrosion inhibitor to these products can mitigate to a certain extent, the unwanted attack on the metallic layers and oxide layers deposited on the substrate. However, since these products have a pH above 11, even in the presence of a corrosion inhibitor, they may attack certain corrosion-sensitive metal layers. Particularly, metal layers such as aluminum or aluminum alloys (e.g., Al-Cu-Si), titanium nitride, titanium tungsten and the like are particularly corrosion sensitive. Furthermore, while the addition of a suitable corrosion inhibitor is essential to prevent corrosion of the substrate metal layers, the corrosion inhibitor must not inhibit the removal of the plasma etching residue.
It is difficult to balance effective plasma etching residue removal corrosion inhibition because chemical compositions of the plasma etching residues are generally similar to those of the metal layers or oxide layers on the substrate. The alkanolamine used in the prior art cleaning compositions was oftentimes found to attack both the plasma etching residue and the substrate metal layers. Moreover, if a post-cleaner rinse such as isopropyl alcohol is not used, the corrosion could be very severe. In addition, some types of the corrosion inhibitors have been found to retard plasma etching residue removal. There has also always been a tradeoff between speed of plasma etching residue removal and substrate metal layer corrosion inhibition. Accordingly, there has remained a need for a method of quickly and effectively removing the plasma etching residues without causing metal layer corrosion
Several other patents in the photoresist stripper/cleaner application field exist as follows, although none of them disclose the use of the method or compositions of the present invention:
Japanese Patent Application No. 7-028254, assigned to Kanto Kagaku, discloses a non-corrosive resist removal liquid comprising a sugar alcohol, an alcohol amine, water, and a quaternary ammonium hydroxide.
PCT Published Patent Application No. WO 88-05813 teaches a positive or negative photoresist stripper containing butyrolactone or caprolactone, quaternary ammonium hydroxide compound, and optionally, a nonionic surfactant.
U.S. Patent No. 4,239,661 to Muraoka et al. discloses a surface-treating agent comprising an aqueous solution of 0.01 % to 20% trialkyl (hydroxyalkyl) ammonium hydroxide. This agent is useful in removing organic and inorganic contaminants deposited on the surface of intermediate semiconductor products.
U.S. Patent No. 4,904,571 to Miyashita et al. teaches printed circuit board photoresist stripper composition containing a solvent (e.g., water, alcohols, ethers, ketones, and the like), an alkaline compound dissolved in the solvent, including quaternary ammonium hydroxide, and a borohydride compound dissolved in the solvent.
U.S. Patent No. 5,091,103 to Dean et al. teaches a positive photoresist stripping composition containing: (A) N-alkyl-2-pyrrolidone; (B) 1,2-propanediol; and (C) tetraalkylammonium hydroxide.
U.S. Patent No. 5,139,607 to Ward et al. teaches positive and negative photoresist stripping composition containing: (A) tetrahydrofurfuryl alcohol; (B) a polyhydric alcohol (e.g., ethylene glycol or propylene glycol); (C) the reaction product of furfuryl alcohol and an alkylene oxide; (D) a water-soluble Bronstead base type hydroxide compound (e.g., alkali metal hydroxide, ammonium hydroxide and tetramethyl ammonium hydroxide); and (E) water. Optionally, the composition may also contain up to 1% of a nonionic surfactant.
U.S. Patent No. 5,174,816 to Aoyama et al. discloses a composition for removing chlorine remaining on the surface of an aluminum line pattern substrate after dry etching, which composition comprises an aqueous solution containing 0.01 to 15% by weight of a quaternary ammonium hydroxide, such as trimethyl (2-hydroxyethyl) ammonium hydroxide, and 0.1 to 20% by weight of sugar or sugar alcohol, such as xylitol, mannose, glucose and the like.
Other compositions used to strip photoresist include a solution of H2SO and an oxidizing agent such as H2O2 that oxidizes, and thus decomposes organic photoresists. However, solutions containing strong acids and oxidizing agents are hazardous to handle, must be applied at elevated temperatures, and require a hot deionized (Dl) water rinse to prevent sulfates from crystallizing on the substrate. Also, such solutions have a short active life as the oxidizing agent readily decomposes. Thus, it is necessary to frequently replenish the solutions. The need for solution replenishment renders the process both hazardous and economically inefficient.
Compared to the foregoing process, the use of a mixture of H2SO and ozone (O3) provides for improved active life since O3 can be bubbled continuously into the solution to maintain oxidation efficiency. However, when plasma etch or a high concentration of arsenic is used in ion implantation, the photoresist film is not completely removed. Also, O3 has limited solubility in H2SO4. U.S. Pat No. 5,378,317 discloses the application of a solution of H2SO4/H2O2 or oxygen plasma ashing followed by a treatment with ozone containing water. However, this process is not capable of removing plasma etch residues such as aluminum oxide, silicon oxide, or aluminum chloride.
Therefore, there remains a need for a method for removing photoresist and plasma etch residues from substrates. Additionally, there remains a need for such a method that does not deleteriously affect the substrate. Further, there remains a need for such a method that uses aqueous-based, non-hazardous cleaning compositions that will not harm the environment.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed to a non-corrosive cleaning method useful for removing photoresist and plasma etch residues from a substrate. The method comprises the steps of: (i) contacting the substrate with an aqueous based cleaning composition having a substantially neutral or mildly acidic pH; and (ii) rinsing the substrate with ozonated water.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
In the first step of the method of the present invention, the substrate is contacted with an aqueous-based cleaning composition having a substantially neutral or slightly acidic pH. One particularly suitable cleaning composition is Microstrip 5002, commercially available from Olin Microelectronic Materials. This stripping solution is described in copending U.S. Patent Application Serial No. 08/709,053, allowed February 20, 1998, the subject matter of which is incorporated herein by reference, and comprises (a) water; (b) at least one hydroxylammonium compound selected from the group consisting of hydroxylammonium salts of the formula (I):
n (NR!R2R3OH)+ (X'n) (I)
wherein Rj, R2 and R3 are individually selected from hydrogen, lower alkyl groups having 1 to 4 carbon atoms, lower alkoxy groups having 1 to 4 carbon atoms, hydroxyl and hydroxyl-substituted lower alkyl groups having 1 to 4 carbon atoms, with the proviso that at least two of R1; R2 and R3 are either hydrogen, lower alkyl group or lower alkoxy group, and wherein X is an anionic moiety that is soluble in water and compatible with said quaternary ammonium hydroxide radical; and n is the valence of X and is from 1 to 3; and
(c) at least one basic compound selected from the group consisting of amines and quaternary ammonium hydroxides. The amount of acidic hydroxylammonium compound relative to the amount of basic amine and/or quaternary ammonium hydroxide is adjusted such that the pH of the overall composition is maintained within the range of about 2 to about 6, preferably within a range from about 2 to about 4. In addition to contributing to the removal of the plasma etching residues, the acidic hydroxylammonium compound inhibits metal attack. Due to the corrosion inhibiting action of acidic component, and the substantially neutral, or only mildly acidic pH, such compositions can be used in the absence of an additional corrosion inhibiting component.
Acidic hydroxylammonium compounds that can be used to form cleaning composition suitable for use with the cleaning method of the invention include hydroxylammonium salts such as hydroxylammonium nitrate (also referred to as HAN) , hydroxylammonium sulfate (also referred to as HAS), hydroxylammonium phosphate, hydroxylammoniun chloride, hydroxylammonium oxalate, hydroxylammonium citrate, hydroxylammonium fluoride, hydroxylammonium chloride, and the like. Alkyl-substituted derivatives of hydroxylammonium salts are also useful: e.g. hydroxyl diethylammonium salts and the like. Preferably, the hydroxylammonium compound is present in the composition of the invention in the range of about 1% to about 70% by weight.
Amines that can be used as the basic component of cleaning compositions useful in the practice of the cleaning method of the invention include hydroxylamine and other alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, diethylene-glycolamine, N- hydroxylethylpiperazine, and the like. Quaternary ammonium hydroxides that can be used as the basic component of cleaning compositions suitable for use in the practice of the cleaning method of the invention include tetraalkylammonium hydroxides having methyl, ethyl, propyl, butyl, hydroxyethyl, and the combinations thereof (e.g., tetramethylammonium hydroxide (hereinafter referred to as TMAH), tetraethyl-ammonium hydroxide, trimethyl hydroxyethylammonium hydroxide, methyl tri (hydroxyethyl) ammonium hydroxide, tetra (hydroxyethyl) ammonium hydroxide, benzyl trimethylammonium hydroxide and the like). Additionally, a combination of ammonium hydroxide with one or more quaternary ammonium hydroxides may also be used. Preferably, the basic compound is present in the cleaning composition of the invention in the range of about 0.01% to about 10% by weight. The balance of cleaning composition can comprise substantially of water.
A chelating stabilizer may be optionally included in the cleaning composition to stabilize the hydroxylammonium salts. Suitable chelating stabilizers include triethylenetetramine (hereinafter referred to as TETA); 2,2'- [[methyl-lH-benzotriazol-l-yl)methyl]imino]bisethanol (Tradename is IRGAMET 42), (2-benzothiazolythio)succinic acid (Tradename is IRGACOR 252), tricine, bicine, and other water-soluble chelating compounds. Preferably, the stabilizer is present in the composition of the invention in the range of about 5 ppm to about 5000 ppm by weight based on the a total weight of cleaning composition.
A surfactant may also be optionally included in the cleaning composition so as to enhance the power of the plasma etching residue removal from the substrate. Suitable surfactants are selected from nonionic types, cationic types and anionic types of surfactants. Preferably, a surfactant is present in the composition of the invention in the range of about 0.1 ppm to about 100 ppm by weight to a total weight of the cleaning composition. The cleaning composition may also, optionally, contain a minor amount of a corrosion inhibitor such as sugar alcohols, catechol and the like.
The substrate can be contacted with the cleaning composition by any suitable method, such as by placing the cleaning composition into a tank and submerging the substrates into the cleaning composition. Preferably, the substrates are spray rinsed with the cleaning composition. The substrates can then be contacted with the ozonated water using any suitable method, such as by placing the ozonated water into a tank where the substrates can be submerged into the water. Preferably, the substrates previously contacted with the cleaning composition are rinsed with the ozonated water using a spray rinse.
The ozonated water can be a simple mixture of ozone and ultra-pure water, e.g., Dl water. The ozone can be generated by any conventional means, e.g., an ozone generator. The mixing of the ozone and water may be achieved by any suitable method, such as jetting the ozone into the water by a gas feed nozzle; feeding the water and ozone into a spiral mixer; aspirating the gas into the flow of water; and feeding the ozone into a treatment tank regulated at a given pressure so that ozone is dissolved into the water.
The cleaning method of the present invention can also be used in combination with a dry stripping process. Dry stripping is typically conducted prior to the present cleaning method. Any suitable dry stripping process can be used including O2 plasma ashing, ozone gas phase-treatment, fluorine plasma treatment, hot H2 gas treatment (described in U.S. Pat. No. 5,691 ,117), and the like. The preferred dry stripping process is O2 plasma ashing.
In addition, the cleaning method can also be used in combination with a organic wet stripping method. The organic wet strip can be performed either before, after, or both before and after the cleaning method of the present invention. Any conventional organic wet stripping solution can be used and a person skilled in the art would be able to choose the appropriate organic wet stripper. Thus, the cleaning method of the invention can be used to replace the organic solvent-based post-strip rinse. Because the preferred cleaning composition is a non-corrosive and neutral to weakly acidic aqueous solution and 10
will not harm the environment. Furthermore, the cleaning compositions used in the present cleaning method may be disposed of in a regular drain system for aqueous chemical wastes.
While the invention has been described above with reference to specific embodiments thereof, it is apparent that many changes, modifications and variations can be made without departing from the inventive concept disclosed herein. Accordingly, it is intended to embrace all such changes, modifications and variations that fall within the spirit and broad scope of the appended claims. All patent applications, patents and other publications cited herein are incorporated by reference in their entirety.

Claims

11WHAT IS CLAIMED IS:
1. A cleaning method for removing photoresist and plasma etch residues comprising the steps of: (i) contacting said substrate with an aqueous based cleaning composition having a pH of from about 2 to about 6; and
(ii) rinsing said substrate with ozonated water.
2. The method of claim 1, wherein said cleaning composition has a pH of from about 2 to about 4.
3. The method of claim 1, wherein said substrate is contacted with said aqueous based cleaning composition by spraying said substrate with said cleaning composition.
4. The method of claim 1, wherein said substrate is rinsed with said ozonated water by spray rinsing.
5. The method of claim 1 , further comprising a step of subjecting said substrate to dry stripping.
6. The method of claim 5, wherein said dry stripping is a plasma oxygen ashing.
7. The method of claim 5, wherein said step of dry stripping is conducted prior to contacting said substrate with said aqueous-based cleaning composition.
8. The method of claim 1 , further comprising a step of subjecting said substrate to organic wet stripping. 12
9. The method of claim 1 wherein said cleaning composition comprises: (A) water; (B) at least one acidic hydroxylammonium compound selected from the group consisting of hydroxylammonium salts of the formula:
n (NR!R2R3OH)+ (X"n)
wherein Rls R2 and R3 are individually selected from hydrogen, lower alkyl groups having 1 to 4 carbon atoms, lower alkoxy groups having 1 to 4 carbon atoms, hydroxyl and hydroxyl-substituted lower alkyl groups having 1 to 4 carbon atoms, with the proviso that at least two of R1; R2 and R3 are hydrogen, lower alkyl group or lower alkoxy group; and wherein X is an anionic moiety that is soluble in water and compatible with said amines or quaternary ammonium hydroxides; and n is the valence of X and is from 1 to 3; and
(C) at least one basic compound selected from amines and quaternary ammonium hydroxides.
10. The method of claim 9, wherein said hydroxylammonium compound is selected from the group consisting of hydroxylammonium nitrate, hydroxylammonium sulfate, hydroxylammonium phosphate, hydroxylammonium oxalate, hydroxylammonium citrate, hydroxylammonium fluoride and hydroxylammonium chloride.
11. The method of Claim 9, wherein the amount of hydroxylammonium compound is from about 1% to about 70% by weight of said cleaning composition. 13
12. The method of Claim 9, wherein said amine is selected from the group consisting of hydroxylamine, monoethanolamine, diethanolamine, triethanolamine, diethyleneglycolamine, and N-hydroxyethylpiperazine.s
13. The method of Claim 9, wherein said quaternary ammonium hydroxide is selected from the group consisting of tetramethylammonium hydroxide, tetraethyl-ammonium hydroxide, trimethyl hydroxyethylammonium hydroxide, methyl tri (hydroxyethyl) ammonium hydroxide, tetra(hydroxyethyl)ammonium hydroxide, and benzyl trimethylammonium hydroxide.
14. The method of claim 9, wherein the amount of said basic compound in the cleaning composition is from about 0.01% to about 10% by weight of said cleaning composition.
15 The method of claim 9, wherein said cleaning composition further comprises a chelating compound selected from the group consisting of triethylenetetramine, 2,2'-[[ (methyl- 1-H-benzotriazoil-l- yl)methyl]imino]bisethanol, and (2-benzothiazolythio) succinic acid.
16. The method of claim 9, wherein said cleaning composition further comprises a surfactant selected from the group consisting of nonionic surfactants, cationic surfactants and anionic surfactants.
17. The method of claim 9, wherein said cleaning composition further comprises a corrosion inhibitor.
18. The method of claim 9, wherein said cleaning composition has a pH of from about 2 to about 4.
PCT/US1998/006907 1998-04-06 1998-04-06 Method for removing photoresist and plasma etch residues WO1999051796A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
JP2000542506A JP2002510752A (en) 1998-04-06 1998-04-06 Method for removing photoresist and plasma etch residue
EP98915347A EP1070157A4 (en) 1998-04-06 1998-04-06 Method for removing photoresist and plasma etch residues
KR1020007011074A KR20010042461A (en) 1998-04-06 1998-04-06 Method for removing photoresist and plasma etch residues
PCT/US1998/006907 WO1999051796A1 (en) 1998-04-06 1998-04-06 Method for removing photoresist and plasma etch residues
AU69556/98A AU6955698A (en) 1998-04-06 1998-04-06 Method for removing photoresist and plasma etch residues

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1998/006907 WO1999051796A1 (en) 1998-04-06 1998-04-06 Method for removing photoresist and plasma etch residues

Publications (1)

Publication Number Publication Date
WO1999051796A1 true WO1999051796A1 (en) 1999-10-14

Family

ID=22266783

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1998/006907 WO1999051796A1 (en) 1998-04-06 1998-04-06 Method for removing photoresist and plasma etch residues

Country Status (5)

Country Link
EP (1) EP1070157A4 (en)
JP (1) JP2002510752A (en)
KR (1) KR20010042461A (en)
AU (1) AU6955698A (en)
WO (1) WO1999051796A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000066697A1 (en) * 1999-05-03 2000-11-09 Ekc Technology, Inc. Compositions for cleaning organic and plasma etched residues for semiconductor devices
CN109503395A (en) * 2018-12-26 2019-03-22 济南蓬勃生物技术有限公司 A kind of stable choline solution and preparation method thereof

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101443886B (en) * 2006-05-30 2012-06-27 Hoya株式会社 Mask blank manufacturing method and transfer mask manufacturing method
CN107589637A (en) * 2017-08-29 2018-01-16 昆山艾森半导体材料有限公司 A kind of fluorine-containing aluminum steel cleaning fluid

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5091103A (en) * 1990-05-01 1992-02-25 Alicia Dean Photoresist stripper
US5181985A (en) * 1988-06-01 1993-01-26 Wacker-Chemitronic Gesellschaft Fur Elektronik-Grundstoffe Mbh Process for the wet-chemical surface treatment of semiconductor wafers
US5314576A (en) * 1992-06-09 1994-05-24 Sony Corporation Dry etching method using (SN)x protective layer
US5494849A (en) * 1995-03-23 1996-02-27 Si Bond L.L.C. Single-etch stop process for the manufacture of silicon-on-insulator substrates
US5516730A (en) * 1994-08-26 1996-05-14 Memc Electronic Materials, Inc. Pre-thermal treatment cleaning process of wafers
US5527872A (en) * 1990-09-14 1996-06-18 At&T Global Information Solutions Company Electronic device with a spin-on glass dielectric layer
US5626681A (en) * 1994-10-21 1997-05-06 Shin-Etsu Handotai Co., Ltd. Method of cleaning semiconductor wafers
US5665168A (en) * 1994-08-30 1997-09-09 Shin-Etsu Handotai Co., Ltd. Method for cleaning semiconductor silicon wafer
US5780406A (en) * 1996-09-06 1998-07-14 Honda; Kenji Non-corrosive cleaning composition for removing plasma etching residues

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5378317A (en) * 1990-10-09 1995-01-03 Chlorine Engineers Corp., Ltd. Method for removing organic film
JP3325739B2 (en) * 1995-03-27 2002-09-17 株式会社ピュアレックス Silicon wafer cleaning method

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5181985A (en) * 1988-06-01 1993-01-26 Wacker-Chemitronic Gesellschaft Fur Elektronik-Grundstoffe Mbh Process for the wet-chemical surface treatment of semiconductor wafers
US5091103A (en) * 1990-05-01 1992-02-25 Alicia Dean Photoresist stripper
US5527872A (en) * 1990-09-14 1996-06-18 At&T Global Information Solutions Company Electronic device with a spin-on glass dielectric layer
US5314576A (en) * 1992-06-09 1994-05-24 Sony Corporation Dry etching method using (SN)x protective layer
US5516730A (en) * 1994-08-26 1996-05-14 Memc Electronic Materials, Inc. Pre-thermal treatment cleaning process of wafers
US5712198A (en) * 1994-08-26 1998-01-27 Memc Electronic Materials, Inc. Pre-thermal treatment cleaning process
US5665168A (en) * 1994-08-30 1997-09-09 Shin-Etsu Handotai Co., Ltd. Method for cleaning semiconductor silicon wafer
US5626681A (en) * 1994-10-21 1997-05-06 Shin-Etsu Handotai Co., Ltd. Method of cleaning semiconductor wafers
US5494849A (en) * 1995-03-23 1996-02-27 Si Bond L.L.C. Single-etch stop process for the manufacture of silicon-on-insulator substrates
US5780406A (en) * 1996-09-06 1998-07-14 Honda; Kenji Non-corrosive cleaning composition for removing plasma etching residues

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP1070157A4 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000066697A1 (en) * 1999-05-03 2000-11-09 Ekc Technology, Inc. Compositions for cleaning organic and plasma etched residues for semiconductor devices
CN109503395A (en) * 2018-12-26 2019-03-22 济南蓬勃生物技术有限公司 A kind of stable choline solution and preparation method thereof
CN109503395B (en) * 2018-12-26 2021-11-16 济南蓬勃生物技术有限公司 Stable choline solution and preparation method thereof

Also Published As

Publication number Publication date
KR20010042461A (en) 2001-05-25
EP1070157A4 (en) 2003-02-12
EP1070157A1 (en) 2001-01-24
AU6955698A (en) 1999-10-25
JP2002510752A (en) 2002-04-09

Similar Documents

Publication Publication Date Title
EP0944708B1 (en) Non-corrosive cleaning composition for removing plasma etching residues
EP1230334B1 (en) Non-corrosive cleaning composition for removing plasma etching residues
KR100620260B1 (en) A cleaning composition and a method for removing residues from a substrate using the same
EP3037511B1 (en) Semi-aqueous photoresist or semiconductor manufacturing residue stripping and cleaning composition with improved silicon passivation
US5977041A (en) Aqueous rinsing composition
US6103680A (en) Non-corrosive cleaning composition and method for removing photoresist and/or plasma etching residues
EP0829768B1 (en) Non-corrosive cleaning composition for removing plasma etching residues
US6245155B1 (en) Method for removing photoresist and plasma etch residues
US20020068684A1 (en) Stripping and cleaning compositions
WO1999051796A1 (en) Method for removing photoresist and plasma etch residues

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GE GH GM GW HU ID IL IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT UA UG UZ VN YU ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW SD SZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN ML MR NE SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 1020007011074

Country of ref document: KR

WWE Wipo information: entry into national phase

Ref document number: 1998915347

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 1998915347

Country of ref document: EP

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

WWP Wipo information: published in national office

Ref document number: 1020007011074

Country of ref document: KR

NENP Non-entry into the national phase

Ref country code: CA

WWW Wipo information: withdrawn in national office

Ref document number: 1998915347

Country of ref document: EP

WWR Wipo information: refused in national office

Ref document number: 1020007011074

Country of ref document: KR