WO2024071417A1 - Solution d'élimination de résidus de gravure sèche - Google Patents

Solution d'élimination de résidus de gravure sèche Download PDF

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WO2024071417A1
WO2024071417A1 PCT/JP2023/035770 JP2023035770W WO2024071417A1 WO 2024071417 A1 WO2024071417 A1 WO 2024071417A1 JP 2023035770 W JP2023035770 W JP 2023035770W WO 2024071417 A1 WO2024071417 A1 WO 2024071417A1
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ions
dry etching
ion
group
solution
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PCT/JP2023/035770
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English (en)
Japanese (ja)
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優人 鑓水
由樹 吉川
伴光 佐藤
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株式会社トクヤマ
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Publication of WO2024071417A1 publication Critical patent/WO2024071417A1/fr

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    • 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
    • C11D3/395—Bleaching agents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching

Definitions

  • the present invention relates to a residue removal solution for removing residues after dry etching in the manufacturing process of semiconductor devices.
  • wiring layers are formed for the purpose of extracting electrical signals generated by transistors to the outside.
  • Semiconductor devices are becoming finer year by year, and if a material with low electromigration resistance or high resistance is used, it will lead to a decrease in reliability of the semiconductor device and an impairment of high-speed operation. Therefore, materials with high electromigration resistance and low resistance are desired as wiring materials. For example, aluminum and copper have been used so far as such materials, and recently, tungsten, cobalt, molybdenum, ruthenium, etc. are being considered.
  • Forming a wiring layer on a semiconductor device includes a process of processing the wiring material, and this process uses dry or wet etching.
  • RuO 4 - or RuO 4 2- changes to RuO 4 in the residue remover, and a part of it gasifies and is released into the gas phase.
  • RuO 4 is not only harmful to the human body because of its strong oxidizing properties, but is also easily reduced to produce RuO 2 particles. In general, particles are a major problem in the semiconductor formation process because they cause a decrease in yield. In this context, it is very important to suppress the generation of RuO 4 gas.
  • Patent Document 1 proposes a semiconductor wafer residue remover solution that contains hypochlorite ions and exhibits a good etching rate and stability of the rate, and is also capable of suppressing the generation of RuO 4 gas.
  • Patent Document 2 proposes a semiconductor wafer residue remover solution that contains hypobromite ions and has a good etching rate and a stable etching rate, and is also capable of suppressing the generation of RuO4 gas.
  • an object of the present invention is to provide an etching residue removing solution which has a high etching residue removing effect and further has an oxidizing agent with good storage stability in the solution.
  • the present inventors have conducted extensive research to solve the above problems. That is, the present invention is configured as follows.
  • a dry etching residue removal solution for removing residues after dry etching comprising one or more oxidizing agents selected from the group consisting of hypobromite ions, bromite ions, bromate ions, hypochlorite ions, chlorite ions, and chlorate ions, one or more metals selected from the group consisting of Mg, Ca, Na, and K, and water;
  • the dry etching residue removing solution has a pH of 9.5 or more and 14 or less at 25° C., and the total content of Mg, Ca, Na, and K in the dry etching residue removing solution is 0.01 ppt or more and 1000 ppt or less.
  • Item 3. The dry etching residue removing solution according to Item 1, wherein the oxidizing agent is hypochlorite ions, and the concentration of the hypochlorite ions is 0.001 mol/L or more and 0.40 mol/L or less.
  • Item 4 The dry etching residue removing solution according to Item 2, wherein the oxidizing agent is hypobromite ions, and the concentration of the hypobromite ions is 0.001 mol/L or more and 0.20 mol/L or less.
  • the dry etching residue removing solution according to any one of Items 1 to 4, further comprising an onium ion, and the surface tension of the residue removing solution is 60 mN/m or more and 75 mN/m or less.
  • Item 6 The dry etching residue removing solution according to Item 5, wherein the onium ion is one or more selected from the group consisting of onium ions represented by formulas (1) to (6).
  • R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are independently an alkyl group having 2 to 9 carbon atoms, an allyl group, an aralkyl group having an alkyl group having 1 to 9 carbon atoms, or an aryl group.
  • At least one hydrogen atom in the aryl group in the aralkyl group and in the ring of the aryl group may be replaced by fluorine, chlorine, an alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, or an alkenyloxy group having 2 to 9 carbon atoms, and in these groups, at least one hydrogen atom may be replaced by fluorine, chlorine, bromine or iodine.
  • A is an ammonium ion or a phosphonium ion.
  • Z is an aromatic group or an alicyclic group which may contain nitrogen, sulfur or oxygen atoms, and in the aromatic group or the alicyclic group, carbon or nitrogen may have chlorine, bromine, fluorine, iodine, at least one alkyl group having 1 to 9 carbon atoms, at least one alkenyloxy group having 2 to 9 carbon atoms, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms.
  • R is chlorine, bromine, fluorine, iodine, an alkyl group having 1 to 9 carbon atoms, an allyl group, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms.
  • n is an integer of 1 or 2 and indicates the number of R. When n is 2, R may be the same or different and may form a ring.
  • a is an integer from 1 to 10.
  • a method for removing dry etching residues from a semiconductor wafer comprising the step of contacting the semiconductor wafer with the dry etching residue removing solution according to any one of items 1 to 7.
  • Item 9 A method for manufacturing a semiconductor device, comprising the steps of dry etching a semiconductor wafer and removing dry etching residues with the dry etching residue removing solution according to any one of Items 1 to 7.
  • Item 10 The method for producing a semiconductor device according to item 9, wherein the semiconductor wafer is a semiconductor wafer containing a ruthenium-based metal.
  • the present invention provides a dry etching residue removal solution that can remove residues on a substrate caused by dry etching in the manufacturing process of semiconductor devices with high efficiency, has excellent storage stability, and maintains the smoothness of the surface of the workpiece, as described below.
  • the dry etching residue removal solution of the present invention is characterized by being a composition containing a specific metal, which will be described later. Furthermore, in the present invention, the dry etching residue removal solution (i.e., the chemical solution used to remove residues after dry etching) is also referred to as the residue removal solution.
  • the workpiece (etching target) to which the residue removing solution of the present invention is applied is a semiconductor wafer containing a transition metal.
  • the manufacturing method of the workpiece is not particularly limited.
  • the workpiece is obtained by the following method.
  • a substrate such as silicon is subjected to an oxidation treatment to form a silicon oxide film on the substrate, and an interlayer insulating film is formed thereon.
  • a photoresist film is formed on the interlayer insulating film, and a via hole is formed in the interlayer insulating film.
  • a metal film is formed in the formed via hole.
  • transition metals include tantalum, silicon, copper, hafnium, zirconium, aluminum, vanadium, cobalt, nickel, manganese, gold, rhodium, palladium, titanium, tungsten, molybdenum, platinum, iridium, and ruthenium, and may contain oxides, nitrides, and silicides thereof. In terms of high electromigration resistance and low resistance value, tungsten, cobalt, molybdenum, and ruthenium are preferred, and ruthenium is particularly preferred.
  • the metal film contained in the workpiece may be formed by any method, such as CVD, ALD, PVD, sputtering, plating, and the like.
  • Dry etching residues are by-products generated by dry etching and are part of the above-mentioned processed object. Examples of the residues include Si-containing residues, metal-containing residues, and organic matter-containing residues derived from photoresist.
  • the dry etching residue removing solution (residue removing solution) of the present invention is a chemical solution used to remove residues generated on a substrate by performing dry etching.
  • the residue removing solution of the present invention contains one or more oxidizing agents selected from the group consisting of hypobromite ions, bromite ions, hypochlorite ions, and chlorate ions, a specific metal described below, and water.
  • Hypochlorite ions and hypobromite ions are oxidizing agents having strong oxidizing properties, and the residue removal solution of the present invention containing hypochlorite ions or hypobromite ions or the like can rapidly etch transition metals under alkaline conditions.
  • the object to be treated is ruthenium
  • the generation of RuO4 gas during etching can be suppressed. This not only improves the wafer processing efficiency per unit time, but also suppresses the yield reduction caused by RuO2 particles, and enables safe processing for the human body, achieving both manufacturing cost and safety.
  • ruthenium can be etched at a stable etching rate while suppressing the generation of RuO4 gas.
  • an oxidizing agent By adding an oxidizing agent to the dry etching residue removing solution of the present invention, it is possible to add a function of removing metals contained in dry etching residues. Furthermore, by adding an oxidizing agent to an alkaline dry etching residue removing solution, it has the effect of decomposing and peeling off organic matter-containing residues, and in an alkaline aqueous solution, the surface potential of the insoluble inorganic matter-containing residues and the treated object is negatively charged, so that the electrostatic repulsion effect prevents the insoluble inorganic matter-containing residues from reattaching to a substrate or the like.
  • the type of oxidizing agent is not particularly limited, and examples thereof include hydrogen peroxide, ozone, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromous acid, bromous acid, bromic acid, perbromic acid, hypoiodous acid, iodous acid, iodic acid, periodic acid (orthoperiodic acid, metaperiodic acid), salts thereof, and ions generated by dissociation of these salts, as well as one or more selected from the group consisting of hydrogen peroxide, ozone, fluorine, chlorine, bromine, iodine, permanganate, chromate, dichromate, and cerium salts.
  • hypobromite ion, bromite ion, bromate ion, hypochlorite ion, chlorite ion, chlorate ion, hypoiodite ion, iodite ion, iodate ion, and periodate ion are preferred because of their strong oxidizing power, stability, and suitability for use in semiconductor applications, and hypobromite ion, bromate ion, bromite ion, hypochlorite ion, chlorate ion, and chlorite ion are more preferred, and hypobromite ion, bromite ion, hypochlorite ion, and chlorate ion are even more preferred.
  • the concentration of the oxidizing agent in the residue removal solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but may be from 0.0001 mol/L to 0.50 mol/L, and preferably from 0.0001 mol/L to 0.40 mol/L. If the concentration is less than 0.0001 mol/L, the dry etching residue removal efficiency is low and the practicality is low. On the other hand, if the concentration exceeds 0.50 mol/L, the oxidizing agent is more likely to decompose, and the dry etching residue removal efficiency may become unstable.
  • the oxidizing agent contained in the residue removing solution of the present invention may be one or more kinds.
  • the type of the oxidizing agent contained in the second kind different from the first kind is not particularly limited, but for example, hydrogen peroxide, ozone, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromous acid, bromous acid, bromic acid, perbromic acid, hypoiodous acid, iodous acid, iodic acid, periodic acid, salts thereof, and ions generated by dissociation of these salts, and further, one or more kinds selected from the group consisting of hydrogen peroxide, ozone, fluorine, chlorine, bromine, iodine, permanganate, chromate, dichromate, and cerium salt can be mentioned.
  • the first kind of oxidizing agent can be hypobromite ion or hypochlorite ion.
  • the residue removal rate may be stabilized, and the stability when reusing the residue removal liquid may be improved.
  • hypobromite ions are included as the first type of oxidizing agent, the hypobromite ions consumed in etching the metal lose their oxidizing power and change to bromide ions. In this case, the more the amount of bromide ions that change to bromide ions, the lower the residue removal ability.
  • the residue removal liquid In semiconductor wafer manufacturing plants, it is common to circulate and reuse the processing liquid from the viewpoint of cost reduction, but if the residue removal ability decreases due to the reuse of the processing liquid, it becomes difficult to stably manufacture semiconductor wafers.
  • multiple types of oxidizing agents are included in the residue removal liquid, for example, when hypochlorite ions are included in addition to hypobromite ions, the bromide ions that have lost their oxidizing power are oxidized by hypochlorite ions and change to hypobromite ions. For this reason, it is possible to suppress the decrease in the concentration of hypobromite ions in the residue removal liquid, and even when the residue removal liquid is reused, the etching rate is less likely to decrease. Furthermore, when the residue removing solution of the present invention contains a plurality of types of oxidizing agents, the total concentration of the oxidizing agents is desirably 0.0001 mol/L or more and 0.40 mol/L or less.
  • the counter cation of the oxidizing agent is not particularly limited, but is preferably a metal ion or an onium ion described later.
  • metal ions include calcium ion, sodium ion, potassium ion, magnesium ion, iron ion, chromium ion, nickel ion, zinc ion, copper ion, and aluminum ion.
  • the counter cation of the oxidizing agent is preferably an onium ion.
  • hypobromite ions may be generated in the residue removal liquid, or may be added to the residue removal liquid as hypobromite.
  • the hypobromite salt referred to here is a salt containing hypobromite ions, or a solution containing the salt.
  • hypobromite ions also written as BrO - or BrO
  • bromine gas may be blown into the residue removal liquid.
  • the residue removal liquid is preferably at 50° C. or less. If the residue removal liquid is at 50° C.
  • the temperature of the residue removal liquid is more preferably at 30° C. or less, and most preferably at 25° C. or less.
  • the temperature of the residue removal solution is preferably ⁇ 35° C. or higher, more preferably ⁇ 15° C. or higher, and most preferably 0° C. or higher.
  • the pH of the residue removal solution into which the bromine gas is blown is blown, but if the pH of the residue removal solution is alkaline, it can be used to remove dry etching residues immediately after hypobromite ions are generated.
  • the solubility of bromine gas (Br 2 ) is improved if the residue removal liquid contains bromide ions (Br - ). This is because Br 2 dissolved in the residue removal liquid reacts with Br - or Br 3 - to form complex ions such as Br 3 - or Br 5 - , which are stabilized in the residue removal liquid.
  • a residue removal liquid containing a large amount of Br 2 , Br - , Br 3 - , Br 5 - or the like can generate more hypobromite ions, and is therefore suitable for use as the residue removal liquid of the present invention.
  • hypobromite ions can be produced in the residue removal solution by oxidizing bromine-containing compounds with an oxidizing agent.
  • hypobromite a compound to the residue removal solution
  • hypobromite, bromine water, and/or hypobromite may be added.
  • hypobromite sodium hypobromite, potassium hypobromite, and tetraalkylammonium hypobromite are preferable, and hypobromite or tetraalkylammonium hypobromite are more preferable because they are substantially free of metal ions that are problematic in semiconductor manufacturing.
  • tetraalkylammonium hypobromite can be easily obtained by passing bromine gas through a tetraalkylammonium hydroxide solution. It can also be obtained by mixing hypobromous acid with a tetraalkylammonium hydroxide solution. Furthermore, tetraalkylammonium hypobromite can also be obtained by replacing the cations contained in hypobromites such as sodium hypobromite with tetraalkylammonium ions using an ion exchange resin.
  • the concentration of the hypobromite ions in the residue removal solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.20 mol/L or less in terms of hypobromite ions. If the concentration is less than 0.001 mol/L, the dry etching residue removal efficiency is low and practicality is low. On the other hand, if the concentration exceeds 0.20 mol/L, decomposition of the hypobromite ions is likely to occur, making it difficult to stabilize the dry etching residue removal efficiency.
  • the concentration of the hypobromite ions is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.005 mol/L or more and 0.20 mol/L or less, and most preferably 0.01 mol/L or more and 0.10 mol/L or less.
  • the ratio of hypobromite ions in 1 mole of bromine element contained in the residue removal solution exceeds 0.5 moles.
  • hypobromite ions are easily converted to Br - by the oxidation reaction or decomposition reaction of ruthenium. Since Br - does not etch metal-containing residues, it is important for stable dry etching residue removal to quickly oxidize Br - in the residue removal solution to hypobromite ions and maintain a high concentration of chemical species (hypobromite ions; BrO - ) having high dry etching residue removal ability.
  • the ratio of hypobromite ions in 1 mole of bromine element contained in the residue removal solution of the present invention exceeds 0.5 moles, that is, when more than half of the bromine elements of the total bromine elements in the residue removal solution are present as BrO - , the concentration of chemical species having dry etching residue removal ability can be considered to be sufficiently high, and the dry etching residue removal efficiency is stabilized.
  • the concentration of hypobromite ions in the residue removal solution can be confirmed using widely known methods. For example, by using ultraviolet-visible spectrophotometry, the absorption caused by hypobromite ions can be easily confirmed, and the hypobromite ion concentration can be calculated from the intensity of the absorption peak (approximately around 330 nm, depending on the pH of the residue removal solution and the hypobromite ion concentration, etc.). Furthermore, the hypobromite ion concentration can also be calculated by iodine titration. The hypobromite ion concentration can also be calculated from the oxidation-reduction potential (ORP) of the residue removal solution.
  • ORP oxidation-reduction potential
  • Measurement by ultraviolet-visible spectrophotometry is the most preferable from the viewpoint of non-contact and continuous measurement. Note that when measuring the hypobromite ion concentration by ultraviolet-visible spectrophotometry, if there is absorption due to other chemical species, the hypobromite ion concentration can be calculated with sufficient accuracy by performing data processing such as spectrum division and baseline correction, and appropriate selection of a reference.
  • the storage stability of the solution can be improved when the concentration is 0.0001 mol/L or more and 0.40 mol/L or less.
  • the concentration of the bromite ion in the residue removing solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.20 mol/L or less in terms of the amount of bromite ion. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is low and practicality is low.
  • the concentration of the bromite ion is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.001 mol/L or more and 0.10 mol/L or less, and most preferably 0.001 mol/L or more and 0.05 mol/L or less.
  • the bromite ions may be generated in the residue removal solution, or may be added to the residue removal solution as a bromite salt.
  • the bromite salt referred to here means a salt containing bromite ions or a solution containing the salt.
  • bromite ions can be produced in the residue removal solution by oxidizing bromine-containing compounds with an oxidizing agent. To add bromite ions as a compound to the residue removal solution, bromite, bromine water, and/or a bromite may be added.
  • bromite sodium bromite, potassium bromite, and tetraalkylammonium bromite are preferable, and bromite or tetraalkylammonium bromite are more preferable in that they are substantially free of metal ions that are problematic in semiconductor manufacturing.
  • the concentration of bromite ions in the residue removal solution can be confirmed by using widely known methods. For example, by using ultraviolet-visible spectrophotometry, the absorption caused by bromite ions can be easily confirmed, and the bromite ion concentration can be calculated from the intensity of the absorption peak (approximately around 298 nm, depending on the pH of the residue removal solution and the bromite ion concentration, etc.). Furthermore, the bromite ion concentration can also be calculated by iodine titration. The bromite ion concentration can also be calculated from the oxidation-reduction potential (ORP) of the residue removal solution. Measurement by ultraviolet-visible spectrophotometry is the most preferable from the viewpoint of non-contact and continuous measurement.
  • the bromite ion concentration when measuring the bromite ion concentration by ultraviolet-visible spectrophotometry, if there is absorption due to other chemical species, the bromite ion concentration can be calculated with sufficient accuracy by performing data processing such as spectrum division and baseline correction, and appropriate selection of a reference.
  • the storage stability of the solution can be improved when the concentration is 0.0001 mol/L or more and 0.40 mol/L or less.
  • the concentration of the bromate ion in the residue removing solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.20 mol/L or less in terms of the amount of bromate ion. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is small and the practicality is low.
  • the concentration of the bromate ion is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.001 mol/L or more and 0.10 mol/L or less, and most preferably 0.001 mol/L or more and 0.05 mol/L or less.
  • the bromate ions may be generated in the residue-removing solution, or may be added to the residue-removing solution as a bromate salt.
  • the bromate referred to here means a salt containing bromate ions, or a solution containing the salt.
  • bromate ions can be produced in the residue removal solution by oxidizing a bromine-containing compound with an oxidizing agent.
  • Bromate ions can be added as a compound to the residue removal solution by adding bromic acid and/or a bromate salt.
  • the bromate salt sodium bromate, potassium bromate, and tetraalkylammonium bromate are preferable, and bromic acid or tetraalkylammonium bromate is more preferable in that it does not contain metal ions that are problematic in semiconductor manufacturing.
  • the concentration of bromate ions in the residue-removed liquid can be confirmed by using a widely known method.
  • the peak of bromate ions can be easily confirmed, and the concentration of bromate ions in the liquid can be obtained from the intensity and peak area of the absorption peak.
  • the concentration of bromate ions can be obtained from the oxidation-reduction potential (ORP) of the residue-removed liquid, liquid chromatography mass spectrometry (LC/MS), and tandem mass spectrometry (LC/MS/MS).
  • hypochlorite ion When the dry etching residue removing solution of the present invention contains hypochlorite ions (also written as ClO ⁇ or ClO), the storage stability of the chemical solution can be improved when the concentration is 0.001 mol/L or more and 0.40 mol/L or less.
  • the hypochlorite ions may be generated in the residue removing liquid, or may be added to the residue removing liquid as hypochlorite.
  • the hypochlorite salt referred to here is a salt containing hypochlorite ions, or a solution containing the salt.
  • chlorine gas may be blown into the residue removing liquid.
  • the residue removing liquid is preferably at 50°C or lower. If the residue removing liquid is at 50°C or lower, not only can hypochlorite ions be efficiently generated, but the generated hypochlorite ions can be stably used for removing dry etching residues. Furthermore, in order to dissolve more chlorine in the residue removing liquid, the temperature of the residue removing liquid is more preferably at 30°C or lower, and most preferably at 25°C or lower. The lower limit of the temperature of the residue removing liquid is not particularly limited, but it is preferable that the residue removing liquid does not freeze.
  • the residue removing liquid is preferably at -35°C or higher, more preferably at -15°C or higher, and most preferably at 0°C or higher.
  • the pH of the residue removal solution into which the chlorine gas is blown is not particularly limited, but if the pH of the residue removal solution is alkaline, it can be used to remove dry etching residues immediately after hypochlorite ions are generated.
  • hypochlorite ions when hypochlorite ions are generated by blowing chlorine gas into the residue removal liquid, the solubility of chlorine gas (Cl 2 ) is improved if the residue removal liquid contains chloride ions (Cl - ). This is because Cl 2 dissolved in the residue removal liquid reacts with Cl - or Cl 3 - to form complex ions such as Cl 3 - or Cl 5 - , which are stabilized in the residue removal liquid.
  • a residue removal liquid containing a large amount of Cl 2 , Cl - , Cl 3 - , Cl 5 - or the like can generate more hypochlorite ions, and therefore can be suitably used as the residue removal liquid of the present invention.
  • hypochlorite ions can be produced in the residue removal solution by oxidizing chlorine-containing compounds with an oxidizing agent.
  • hypochlorous acid chlorine water, and/or hypochlorite may be added.
  • hypochlorite sodium hypochlorite, potassium hypochlorite, and tetraalkylammonium hypochlorite are preferable, and hypochlorous acid or tetraalkylammonium hypochlorite is more preferable because it is substantially free of metal ions that are problematic in semiconductor manufacturing.
  • the tetraalkylammonium hypochlorite can be easily obtained by passing chlorine gas through a tetraalkylammonium hydroxide solution.
  • hypochlorous acid can also be mixed with a tetraalkylammonium hydroxide solution.
  • tetraalkylammonium hypochlorite can also be obtained by replacing the cation contained in hypochlorite such as sodium hypochlorite with tetraalkylammonium ion using ion exchange resin.
  • the concentration of the hypochlorite ions in the residue removal solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.40 mol/L or less in terms of hypochlorite ions. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is low and practicality is low. On the other hand, if it exceeds 0.40 mol/L, decomposition of the hypochlorite ions is likely to occur, and the dry etching residue removal efficiency becomes less stable.
  • the concentration of the hypochlorite ions is preferably 0.001 mol/L or more and 0.40 mol/L or less, more preferably 0.01 mol/L or more and 0.30 mol/L or less, and most preferably 0.1 mol/L or more and 0.20 mol/L or less.
  • the concentration of hypochlorite ions in the residue removal solution can be confirmed using widely known methods. For example, by using ultraviolet-visible spectrophotometry, the absorption caused by hypochlorite ions can be easily confirmed, and the hypochlorite ion concentration can be calculated from the intensity of the absorption peak (approximately around 292 nm, depending on the pH of the residue removal solution and the hypochlorite ion concentration, etc.). Furthermore, the hypochlorite ion concentration can also be calculated by iodometric titration. The hypochlorite ion concentration can also be calculated from the oxidation-reduction potential (ORP) of the residue removal solution.
  • ORP oxidation-reduction potential
  • Measurement by ultraviolet-visible spectrophotometry is the most preferable from the viewpoint of non-contact and continuous measurement. Note that when measuring the hypochlorite ion concentration by ultraviolet-visible spectrophotometry, if there is absorption due to other chemical species, the hypochlorite ion concentration can be calculated with sufficient accuracy by performing data processing such as spectrum division and baseline correction, and appropriate selection of a reference.
  • the storage stability of the chemical solution can be improved when the concentration is 0.0001 mol/L or more and 0.40 mol/L or less.
  • the concentration of the chlorite ion in the residue removing solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.20 mol/L or less as the amount of chlorite ion. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is small and practical.
  • the concentration of the chlorite ion is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.001 mol/L or more and 0.10 mol/L or less, and most preferably 0.001 mol/L or more and 0.05 mol/L or less.
  • the chlorite ion may be generated in the residue removing solution, or may be added to the residue removing solution as a chlorite.
  • the chlorite salt referred to here means a salt containing chlorite ion or a solution containing the salt.
  • chlorite ions can be produced in the residue removal solution by oxidizing chlorine-containing compounds with an oxidizing agent.
  • chlorous acid, chlorine water, and/or a chlorite may be added.
  • chlorite sodium chlorite, potassium chlorite, and tetraalkylammonium chlorite are preferable, and chlorous acid or tetraalkylammonium chlorite is more preferable in that it is substantially free of metal ions that are problematic in semiconductor manufacturing.
  • the concentration of chlorite ions in the residue removal solution can be confirmed by using a widely known method. For example, by using ion chromatography analysis, the peak of chlorite ions can be easily confirmed, and the concentration of chlorite ions in the solution can be obtained from the intensity and area of the absorption peak.
  • chlorate ion When the dry etching residue removing solution of the present invention contains chlorate ions (ClO 3 ⁇ , also written as ClO 3 ), the storage stability of the solution can be improved when the concentration is 0.0001 mol/L or more and 0.40 mol/L or less.
  • the concentration of the chlorate ion in the residue removing solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but preferably, the amount of chlorate ion is 0.001 mol/L or more and 0.20 mol/L or less. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is small and practical.
  • the concentration of the chlorate ion is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.001 mol/L or more and 0.10 mol/L or less, and most preferably 0.001 mol/L or more and 0.05 mol/L or less.
  • the chlorate ions may be generated in the residue-removing solution, or may be added to the residue-removing solution as a chlorate salt.
  • the chlorate referred to here means a salt containing chlorate ions, or a solution containing the salt.
  • chlorine-containing compounds can be oxidized with an oxidizing agent to produce chlorate ions in the residue removal solution.
  • chloric acid and/or a chlorate may be added.
  • sodium chlorate, potassium chlorate, and tetraalkylammonium chlorate are preferable, and chloric acid or tetraalkylammonium chlorate is more preferable because it does not contain metal ions that are problematic in semiconductor manufacturing.
  • the concentration of chlorate ion in the residue-removing solution can be confirmed by using a widely known method.For example, by using ion chromatography analysis, the peak of chlorate ion can be easily confirmed, and the concentration of chlorate ion in the solution can be obtained from the intensity and peak area of the absorption peak.Otherwise, the concentration of chlorate ion can be obtained from the oxidation-reduction potential (ORP) of the residue-removing solution.
  • ORP oxidation-reduction potential
  • the acid dissociation constant (pK a ) of hypobromous acid (HBrO) and hypobromite ion (BrO ⁇ ) is 8.6, and the acid dissociation constant (pK a ) of hypochlorous acid (HClO) and hypochlorite ion (ClO ⁇ ) is 7.5, so that when the pH is low, HBrO and BrO ⁇ , or HClO and ClO ⁇ may coexist depending on the pH of the residue removal solution.
  • the residue removal solution contains HBrO and BrO ⁇
  • the total concentration of HBrO and BrO ⁇ may be treated as the concentration of the hypobromite ion.
  • the residue removal solution contains HClO and ClO ⁇
  • the total concentration of HClO and ClO ⁇ may be treated as the concentration of the hypochlorite ion.
  • an acid or an alkali can be added to the residue removal solution.
  • the acid may be either an inorganic acid or an organic acid, and examples include hydrofluoric acid, hydrochloric acid, hydrobromic acid, nitric acid, acetic acid, sulfuric acid, peroxodisulfuric acid, formic acid, carboxylic acids such as acetic acid, and other widely known acids used in residue removal solutions for semiconductors can be used without any restrictions.
  • the alkali it is preferable to use an organic alkali because it does not contain metal ions that are problematic in semiconductor manufacturing.
  • tetraalkylammonium hydroxide which is composed of tetraalkylammonium ions and hydroxide ions.
  • examples of the tetraalkylammonium hydroxide include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, ethyltrimethylammonium hydroxide, propyltrimethylammonium hydroxide, and the like.
  • the organic alkali is preferably tetraalkylammonium hydroxide, and more preferably tetramethylammonium hydroxide, because it has a large number of hydroxide ions per unit weight and is easily available as a high-purity product.
  • the residue removing solution may contain one type of tetraalkylammonium ion, or a combination of two or more types of tetraalkylammonium ions.
  • the dry etching residue removal solution contains one or more metals selected from the group consisting of Mg, Ca, Na, and K in an amount of 0.01 ppt or more and 1000 ppt or less as specific metals, which further has the effect of maintaining the surface smoothness of the workpiece.
  • the target mixture is adsorbed onto the surface of the transition metal-containing material to homogenize the electronic state, and therefore, there is an effect of maintaining the smoothness of the surface of the treated object by containing one or more metals selected from the group consisting of Mg, Ca, Na, and K in the residue removal solution.
  • the total content of one or more metals selected from the group consisting of Mg, Ca, Na, and K contained in the residue removal solution is 0.01 ppt or more and 1000 ppt or less, more preferably 0.01 ppt or more and 200 ppt or less, and even more preferably 0.01 ppt or more and 50 ppt or less.
  • the dry etching residue removal solution may contain only Mg, only Ca, only Na, only K, Mg, Ca, Na, and K, Mg, Ca, and Na, only Mg, Ca, and K, only Mg, Na, and K, only Ca, Na, and K, only Mg and Ca, only Mg and Na, only Mg and K, only Ca and Na, only Ca and K, or only Na and K.
  • the content of a specific metal contained in the etching residue removal solution is the total content of all metals contained therein.
  • the dry etching residue removal solution may contain one or more metals selected from the group consisting of alkali metals other than Mg, Ca, Na, and K, alkaline earth metals, Fe, Cr, Ni, Zn, Cu, and Al. These do not contribute to the smoothness of the surface, but may be contained.
  • the dry etching residue removing solution of the present invention may contain chloride ions, bromide ions, and iodide ions derived from the manufacturing process or raw materials. The contents of these ions may be used without problems as long as they are at concentrations that do not affect the removal of dry etching residues, and each concentration of these ions preferably does not exceed 1 mass %.
  • the residue removal solution contains onium ions, which are effective in maintaining the smoothness of the surface. Since the surface of the workpiece is also etched by the residue removal step, it is required that the smoothness of the surface does not change before and after the treatment. In order to maintain the smoothness of the surface of the workpiece within a preferred range, it is preferable to select one or more types selected from the group consisting of onium ions having structures represented by the following formulas (1) to (6).
  • R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are independently an alkyl group having 2 to 9 carbon atoms, an allyl group, an aralkyl group having an alkyl group having 1 to 9 carbon atoms, or an aryl group.
  • At least one hydrogen atom in the aryl group in the aralkyl group and in the ring of the aryl group may be replaced by fluorine, chlorine, an alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, or an alkenyloxy group having 2 to 9 carbon atoms, and in these groups, at least one hydrogen atom may be replaced by fluorine, chlorine, bromine or iodine.
  • Examples of counter anions to the onium ions include fluoride ion, chloride ion, bromide ion, iodide ion, hydroxide ion, nitrate ion, phosphate ion, sulfate ion, hydrogen sulfate ion, methanesulfate ion, perchlorate ion, chlorate ion, chlorite ion, hypochlorite ion, perbromate ion, bromate ion, bromite ion, hypobromite ion, orthoperiodate ion, metaperiodate ion, iodate ion, iodite ion, hypoiodite ion, acetate ion, carbonate ion, hydrogen carbonate ion, fluoroborate ion, and trifluoroacetate ion.
  • A is an ammonium ion or a phosphonium ion.
  • Z is an aromatic group or an alicyclic group which may contain nitrogen, sulfur or oxygen atoms, and in the aromatic group or the alicyclic group, carbon or nitrogen may have chlorine, bromine, fluorine, iodine, at least one alkyl group having 1 to 9 carbon atoms, at least one alkenyloxy group having 2 to 9 carbon atoms, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms.
  • R is chlorine, bromine, fluorine, iodine, an alkyl group having 1 to 9 carbon atoms, an allyl group, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms.
  • n is an integer of 1 or 2 and indicates the number of R. When n is 2, R may be the same or different and may form a ring.
  • a is an integer from 1 to 10.
  • the residue removal solution contains onium ions, which can suppress the generation of gas due to metal oxides.
  • the object to be treated is ruthenium
  • the ruthenium is oxidized by the oxidizing agent in the residue removal solution to generate RuO 4 - , RuO 4 2- , etc.
  • the generated RuO 4 - , RuO 4 2- , etc. interact with the onium ions to suppress the generation of RuO 4 gas.
  • the concentration of the onium ion in the residue removing solution of the present invention is preferably 1 mass ppm or more and 10,000 mass ppm or less. If the amount of onium ion added is too small, not only the interaction with the workpiece such as RuO 4 - is weakened, for example, the RuO 4 gas suppression effect is reduced, but also the amount of onium ion attached to the metal surface during residue removal is insufficient, so that the surface smoothness tends to decrease. On the other hand, if the amount added is too large, the amount of onium ion adsorbed to the metal surface becomes excessive, and the residue removal rate decreases.
  • the residue removing solution of the present invention preferably contains onium ion in an amount of 1 mass ppm or more and 10,000 mass ppm or less, more preferably 10 mass ppm or more and 5,000 mass ppm or less, and even more preferably 50 mass ppm or more and 2000 mass ppm or less.
  • onium ions When onium ions are added, only one type may be added, or two or more types may be added in combination. Even when two or more types of onium ions are contained, so long as the total concentration of the onium ions is within the above concentration range, the generation of RuO4 gas can be effectively suppressed.
  • onium ions examples include chlorocholine ion, bromocholine, trans-2-butene 1,4-bis(triphenylphosphonium ion), 1-hexyl-3-methylimidazolium ion, allyltriphenylphosphonium ion, tetraphenylphosphonium ion, benzyltriphenylphosphonium ion, methyltriphenylphosphonium ion, (2-carboxyethyl)triphenylphosphonium ion, (3-carboxypropyl)triphenylphosphonium ion, (4-carboxybutyl)triphenylphosphonium ion, (5-carboxypentyl)triphenylphosphonium ion, cinnamyltriphenylphosphonium ion, (2-hydroxybenzyl)triphenylphosphonium ion, (1-naphthylmethyl)triphenylphosphonium ion,
  • the effects of onium ions include suppressing surface roughness during residue removal and suppressing RuO 4 gas, but in addition to this, they also have the effect of improving the number of times of reuse when used as a semiconductor residue removal solution.
  • used residue removal solutions are sometimes recycled through circulation filtration.
  • metals dissolve into the residue removal solution, so the composition of the residue removal solution differs before and after use.
  • ruthenium residue removal using hypobromite ions ruthenium dissolves as RuO 4 - under alkaline conditions.
  • hypobromite ions react with RuO 4 - or RuO 4 2- or RuO 4 generated by changing RuO 4 - , the concentration of hypobromite ions, which are chemical species effective for residue removal, decreases. Therefore, the more times the residue removal solution is reused and the longer the reuse time, the lower the residue removal rate.
  • the stability during reuse may be improved. That is, RuO 4 - and the like react positively with the onium ion, and it becomes possible to suppress the reaction between RuO 4 - and the like and hypobromite ion.
  • an onium ion that can be used for such a purpose a phosphonium ion is preferable.
  • ammonium ion there is a concern that an amine may be generated by reaction with hypobromite ion, and this amine may decompose hypobromite ion.
  • the residue removing liquid contains onium ions and has a surface tension of 60 mN/m or more and 75 mN/m or less. Note that the surface tension is measured at 25° C.
  • the residue removing solution of the present invention contains an oxidizing agent, in order to prevent the stability of the oxidizing agent from decreasing and the inhibition of residue removal from occurring, the surface tension is preferably set to 75 mN/m or less.
  • One method for increasing the surface tension of the residue removal solution is to add a salt containing an anion with a high degree of hydration.
  • a salt containing an anion with a high degree of hydration By adding an anion with a high degree of hydration, the neutralization of the charge of the onium ion by the anion is inhibited, and the electrical repulsion between the onium ions is maintained, thereby increasing the surface tension.
  • anions with a high degree of hydration include fluoride ions, chloride ions, and bromide ions.
  • the surface tension can be measured in accordance with JIS 2241 "Test method using a Wilhelmy surface tensiometer.”
  • onium ions examples include allyltriphenylphosphonium ion, tetraphenylphosphonium ion, trans-2-butene-1,4-bis(triphenylphosphonium ion), benzyltriphenylphosphonium ion, tetrabutylphosphonium ion, tributylhexylphosphonium ion, heptyltriphenylphosphonium ion, cyclopropyltriphenylphosphonium ion, (bromomethyl)triphenylphosphonium ion, (chloromethyl)triphenylphosphonium ion, etc.
  • Ruthenium which is an example of the object to be treated in the present invention, may be a ruthenium-based metal or a ruthenium alloy.
  • the material to be treated is a ruthenium-based metal and the pH is 9.5 or more and 14 or less at 25° C., harmful RuO 4 gas is unlikely to be generated and particles due to RuO 2 are also few.
  • hypobromite ions and hypochlorite ions dissolve ruthenium Although the details of the mechanism by which hypobromite ions and hypochlorite ions dissolve ruthenium are not necessarily clear, it is presumed that hypobromite ions or hypobromous acid generated from hypobromite ions in the residue removal solution, or hypochlorite ions or hypochlorite ions generated from hypochlorite ions in the residue removal solution, oxidize ruthenium to RuO 4 , RuO 4 - or RuO 4 2- , and dissolve in the residue removal solution. By dissolving ruthenium as RuO 4 - or RuO 4 2- , it is possible to reduce the amount of RuO 4 gas generated and suppress the generation of RuO 2 particles.
  • the pH of the residue removal solution is preferably 9.5 or more and 14 or less, more preferably 12 or more and 14 or less, and most preferably 12 or more and less than 13. If the pH of the residue removing solution is 12 or more but less than 13, ruthenium dissolves in the residue removing solution as RuO 4 - or RuO 4 2- , so that the amount of RuO 4 gas generated can be significantly reduced and the generation of RuO 2 particles can be suppressed.
  • ruthenium-based metal refers to ruthenium metal containing 70 atomic % or more of ruthenium, ruthenium oxide ( RuOx ), nitride (RuN), oxynitride (RuNO), etc.
  • ruthenium oxide refers to ruthenium dioxide and ruthenium trioxide (trihydrate).
  • ruthenium alloy refers to an alloy containing 70 atomic % or more and 99.99 atomic % or less of ruthenium and containing a metal other than ruthenium at a concentration higher than the concentration that is inevitably contained. In the present invention, when there is no need to particularly distinguish between ruthenium-based metal and ruthenium alloy, they are described as ruthenium.
  • the ruthenium alloy may contain any metal other than ruthenium.
  • metals contained in the ruthenium alloy include tantalum, silicon, copper, hafnium, zirconium, aluminum, vanadium, cobalt, nickel, manganese, gold, rhodium, palladium, titanium, tungsten, molybdenum, platinum, and iridium, and the alloy may contain oxides, nitrides, and silicides of these metals.
  • These ruthenium compounds may be intermetallic compounds, ionic compounds, or complexes. Ruthenium may be exposed on the surface of the wafer, or may be covered with other metals, metal oxide films, insulating films, resists, or the like.
  • the residue removing solution of the present invention can suppress RuO4 gas generated from very small amounts of dissolved ruthenium even in the case where ruthenium is not actively dissolved, that is, even in the case of a process in which ruthenium is the object of protection.
  • the method for producing a semiconductor device of the present invention includes a step of dry etching a semiconductor wafer, and a step of removing dry etching residues with the above-mentioned dry etching residue removing solution. Furthermore, the method may include a metal film forming step of forming a semiconductor wafer by forming a metal film on a semiconductor substrate before the step of dry etching the semiconductor wafer, and may include a step of rinsing the semiconductor wafer and a step of drying the semiconductor wafer before and/or after the step of removing the dry etching residues.
  • the residue can be removed more efficiently than when only dry etching is used. Furthermore, compared to when only wet etching is used, the surface smoothness of the metal film can be maintained.
  • the semiconductor wafer can be cleaned by contacting the semiconductor wafer with a rinsing liquid.
  • the rinsing liquid can be selected from the group consisting of water, functional water such as ozone water, radical water, and electrolytic ion water, organic solvents such as 2-propanol, ammonia-hydrogen peroxide mixtures, hydrochloric acid-hydrogen peroxide mixtures, sulfuric acid-hydrogen peroxide mixtures, nitric acid-hydrofluoric acid mixtures, hydrofluoric acid, sulfuric acid, phosphoric acid, nitric acid, buffered hydrofluoric acid, ammonia, hydrogen peroxide, hydrochloric acid, tetramethylammonium hydroxide (TMAH), and mixtures of these with water.
  • functional water such as ozone water, radical water, and electrolytic ion water
  • organic solvents such as 2-propanol
  • ammonia-hydrogen peroxide mixtures such as ozone water, radical water, and electrolytic ion water
  • organic solvents such as 2-propanol
  • the step of drying the semiconductor wafer is not particularly limited, but the drying can be performed by spin drying, IPA drying, Marangoni drying, Rotagoni drying, or the like.
  • the method for manufacturing a semiconductor device may also include known steps used in the manufacture of semiconductor devices, such as one or more steps selected from a wafer fabrication step, an oxide film formation step, a transistor formation step, a wiring formation step, and a CMP step.
  • the substrate on which the dry etching is performed is a semiconductor wafer containing a transition metal.
  • the transition metal film may be formed on the substrate by any method, such as CVD, ALD, PVD, sputtering, plating, etc.
  • the dry etching method is not particularly limited and can be performed by a known method, but it is preferable to dry etch using an O 2 /Cl 2 mixed gas.
  • the dry etching is preferably reactive ion etching.
  • capacitive coupled plasma-RIE capacitive coupled plasma-RIE, inductive coupled plasma-RIE, or ECR (Electron Cyclotron Resonance-RIE) is preferable.
  • ECR Electro Cyclotron Resonance-RIE
  • dry etching residues such as Si-containing residues, metal-containing residues, and organic substance-containing residues derived from photoresist are generated.
  • the residue removing solution of the present invention is suitably used for removing these dry etching residues.
  • the residue-removing solution of the present invention can remove dry etching residues from a semiconductor wafer by contacting the semiconductor wafer. That is, the method for removing dry etching residues from a semiconductor wafer of the present invention includes a step of contacting the semiconductor wafer with the residue-removing solution.
  • the method for removing dry etching residues of the present invention can also be used as a method for cleaning semiconductor wafers.
  • the method for cleaning semiconductor wafers also includes a step of contacting the semiconductor wafer with the above-mentioned residue removing solution, similar to the method for removing dry etching residues.
  • the method for bringing the semiconductor wafer into contact with the residue-removing liquid is not particularly limited, and may be appropriately selected according to the cleaning conditions of the cleaning device used and the semiconductor wafer used.
  • a method of spraying the residue-removing liquid onto the semiconductor wafer a method of immersing the semiconductor wafer in a container containing the residue-removing liquid, a method of dripping the residue-removing liquid onto the semiconductor wafer, a method of bringing the semiconductor wafer into contact with the residue-removing liquid and applying ultrasonic waves to promote residue removal, and any combination thereof.
  • the temperature at which the residue removing solution of the present invention is used is in the range of 10 to 80° C., preferably 20 to 70° C., and may be appropriately selected depending on the cleaning conditions of the cleaning device used and the semiconductor wafer used.
  • the time for which the residue removing solution of the present invention is used is 0.1 to 120 minutes, preferably 0.5 to 60 minutes, per wafer, and may be appropriately selected according to the cleaning conditions of the cleaning device used and the semiconductor wafer used.
  • the container for storing the residue removing liquid of the present invention is not particularly limited, but it is preferable that the container is highly clean and that impurities are less likely to be eluted from the container, and the inner surface of the container that comes into contact with the liquid is preferably made of an organic polymer material because it is less likely to elute metal components.
  • the organic polymer material used for the inner surface of the container vinyl chloride resins (soft and hard vinyl chloride resins), nylon resins, silicone resins, polyolefin resins (polyethylene, polypropylene), fluororesins, etc. can be used, and among them, polyolefin resins or fluororesins are preferable in consideration of ease of molding, solvent resistance, and less elution of impurities.
  • a substrate made of silicon was prepared.
  • the prepared substrate was subjected to an oxidation treatment to form a silicon oxide film of 500 nm on the silicon.
  • an interlayer insulating film of 50 nm made of a low dielectric constant (Low-k) film was formed, a photoresist film was formed on the interlayer insulating film, and a via hole was formed in the interlayer insulating film.
  • a ruthenium film of 20 nm was formed in the formed via hole.
  • the workpiece (semiconductor substrate) on which the ruthenium film was formed by the above method was subjected to dry etching treatment using a reactive ion etching apparatus (RIE-400IPC manufactured by Samco Corporation).
  • RIE-400IPC reactive ion etching apparatus
  • the workpiece dry-etched by the above method was cut into 10 x 20 mm pieces.
  • 60 mL of the dry etching residue removal solution was prepared in a fluororesin container with a lid (AsOne, PFA container 94.0 mL).
  • the workpiece after dry etching prepared by the above method was immersed in the dry etching residue removal solution at 30°C for 1 minute.
  • the residue removal rate X ( ⁇ - ⁇ ) / ⁇ ⁇ 100, and was evaluated according to the following criteria. In both cases, evaluations A to C were considered to be acceptable levels, and evaluation D was considered to be unacceptable levels.
  • the amount of RuO 4 gas generated was measured using ICP-OES. 5 mL of the dry etching residue removal solution was placed in a sealed container, and one 10 ⁇ 20 mm ruthenium film having a thickness of 120 nm was immersed at 30° C. until all of the ruthenium was dissolved. Thereafter, air was flowed into the sealed container, and the gas phase in the sealed container was bubbled into a container containing an absorbing solution (1 mol/L NaOH), and the RuO 4 gas generated during immersion was trapped in the absorbing solution.
  • the storage stability evaluation of the oxidizing agent in the residue removal solution was measured using an ultraviolet-visible spectrophotometer (UV-2600, manufactured by Shimadzu Corporation). 5 L of the dry etching residue removal solution was prepared in a light-shielding pure bottle (manufactured by Kodama Resin Industry Co., Ltd., PFA container 5 L) and stored at 25°C while being shielded from light. Thereafter, the oxidizing agent concentration in the dry etching residue removal solution was periodically measured for 6 months using an ultraviolet-visible spectrophotometer (UV-2600, manufactured by Shimadzu Corporation).
  • UV-2600 ultraviolet-visible spectrophotometer
  • the oxidizing agent concentration immediately after production was set to 100%, and the oxidizing agent concentration in the dry etching residue removal solution after 6 months was evaluated according to the following criteria. In both cases, evaluations A to C were considered to be acceptable levels, and evaluation D was considered to be unacceptable levels.
  • a rotor (AsOne, total length 30 mm x diameter 8 mm) was placed in a three-neck flask, a thermometer protection tube (Cosmos Bead, bottom-sealed type) and a thermometer were placed in one opening, a chlorine gas cylinder and a nitrogen gas cylinder were connected to the other opening, and the tip of a PFA tube (Flon Industries, F-8011-02) that was connected to a state in which chlorine gas/nitrogen gas could be switched at will was immersed in the bottom of the solution, and the remaining opening was connected to a gas washing bottle (AsOne, gas washing bottle, model number 2450/500) filled with a 5% by mass aqueous sodium hydroxide solution.
  • a gas washing bottle (AsOne, gas washing bottle, model number 2450/500) filled with a 5% by mass aqueous sodium hydroxide solution.
  • nitrogen gas with a carbon dioxide concentration of less than 1 ppm was flowed from the PFA tube at 0.289 Pa ⁇ m 3 /sec (at 0°C) for 20 minutes to expel carbon dioxide from the gas phase.
  • the carbon dioxide concentration in the gas phase was 1 ppm or less.
  • a magnetic stirrer (AsOne Corp., C-MAG HS10) was placed at the bottom of the three-neck flask and rotated and stirred at 300 rpm, and while the outer periphery of the three-neck flask was cooled with ice water, chlorine gas (Fujiox Corp., specification purity 99.4%) was supplied at 0.059 Pa ⁇ m 3 /sec (at 0°C) for 180 minutes to obtain a mixed solution of tetramethylammonium hypochlorite aqueous solution (oxidizing agent; equivalent to 3.51% by mass, 0.28 mol/L) and tetramethylammonium hydroxide (equivalent to 0.09% by mass, 0.0097 mol/L).
  • oxidizing agent equivalent to 3.51% by mass, 0.28 mol/L
  • tetramethylammonium hydroxide equivalent to 0.09% by mass, 0.0097 mol/L
  • the liquid temperature during the reaction was 11°C.
  • 0.1 g of sodium hydroxide aqueous solution (0.1 mol/L, Wako Pure Chemical Industries, Ltd.) was weighed into a 100 ml PFA bottle (AsOne, ACPFA100-N) and diluted to 100 ml.
  • 0.1 g of the diluted solution obtained by the above operation was weighed into a 100 ml PFA bottle (AsOne, ACPFA100-N) and diluted to 100 ml. In this way, a metal-containing liquid was obtained.
  • the tetramethylammonium hypochlorite solution obtained by the above operation, ultrapure water, onium salt, tetramethylammonium hydroxide (25% by mass, manufactured by Tokuyama Corporation), hydrochloric acid, and the metal-containing liquid obtained by the above operation were added and mixed to the concentrations shown in Tables 1 to 3 to obtain residue removing solutions having the compositions shown in Examples 19 to 29 and 40 to 42.
  • the metals contained in the residue removing solution are those shown in the metals contained in the dry etching residue removing solution, and the metal concentrations in the residue removing solution are concentrations calculated from the total contents of Mg, Ca, Na, and K contained in the residue removing solution.
  • Examples 2 to 12 and 36 to 38 were also manufactured and evaluated in the same manner.
  • the metals contained in the residue removal solution are the metals described in the metals contained in the dry etching residue removal solution, and the metal concentration in the residue removal solution is the concentration calculated from the total content of Mg, Ca, Na, and K contained in the residue removal solution.
  • the metals contained in the residue removing solution are the metals shown in the metals contained in the dry etching residue removing solution, and the metal concentrations in the residue removing solution are concentrations calculated from the total contents of Mg, Ca, Na, and K contained in the residue removing solution.
  • Commercially available sodium chlorite was added to ultrapure water to obtain a sodium chlorite solution.
  • This sodium chlorite solution was passed through an ion exchange resin that had been ion-exchanged to a tetramethylammonium type, and the sodium ions were replaced with tetramethylammonium ions to obtain a tetramethylammonium chlorite solution.
  • the metals contained in the residue removing solutions are the metals shown in the metals contained in the dry etching residue removing solutions, and the metal concentrations in the residue removing solutions are concentrations calculated from the total contents of Mg, Ca, Na, and K contained in the residue removing solutions.
  • the tetramethylammonium hypochlorite solution obtained by the above operation was mixed with equimolar tetramethylammonium bromide to obtain a tetramethylammonium hypobromite solution.
  • the tetramethylammonium hypochlorite solution obtained by the above operation, the tetramethylammonium bromite solution, the tetramethylammonium chlorate solution, the onium salt, the tetramethylammonium hydroxide (25% by mass, manufactured by Tokuyama Corporation), the hydrochloric acid, and the metal-containing solution obtained by the above operation were added to the tetramethylammonium hypobromite solution to the concentrations described in Table 4, and the residue-removing solution having the composition described in Examples 44 to 46 was obtained.
  • the metals contained in the residue-removing solution are the metals described in the metals contained in the dry etching residue-removing solution, and the metal concentration in the residue-removing solution is the concentration calculated from the total content of Mg, Ca, Na, and K contained in the residue-removing solution.
  • the amount of metal was measured using a triple quadrupole inductively coupled plasma mass spectrometer (ICP-8900, manufactured by Agilent Technologies). A calibration curve was created using standard elemental solutions for ICP analysis containing Mg, Ca, Na, K, Fe, Cr, Ni, Zn, Cu, and Al, and the metal concentration in the treatment solution was measured.
  • ICP-8900 triple quadrupole inductively coupled plasma mass spectrometer

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Abstract

L'invention concerne une solution d'élimination de résidus de gravure sèche contenant : au moins un oxydant choisi dans le groupe constitué par les ions hypobromite, les ions bromate, les ions bromite, les ions hypochlorite, les ions chlorate et les ions chlorite ; au moins un métal choisi dans le groupe constitué par Mg, Ca, Na et K ; et de l'eau, le pH de la solution d'élimination de résidus étant de 9,5-14 à 25 °C, et la teneur totale en Mg, Ca, Na et K dans la solution d'élimination de résidus de gravure sèche étant de 0,01 à 1000 ppt.
PCT/JP2023/035770 2022-09-29 2023-09-29 Solution d'élimination de résidus de gravure sèche WO2024071417A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019142788A1 (fr) * 2018-01-16 2019-07-25 株式会社トクヤマ Liquide de traitement pour tranches de semi-conducteur, qui contient des ions hypochlorite
WO2021060234A1 (fr) * 2019-09-27 2021-04-01 株式会社トクヤマ AGENT INHIBANT LA GENERATION DE GAZ RuO4 ET PROCEDE INHIBANT LA GENERATION DE GAZ RuO4
WO2021059666A1 (fr) * 2019-09-27 2021-04-01 株式会社トクヤマ Liquide de traitement pour semi-conducteur de ruthenium et procede de production de celui-ci

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019142788A1 (fr) * 2018-01-16 2019-07-25 株式会社トクヤマ Liquide de traitement pour tranches de semi-conducteur, qui contient des ions hypochlorite
WO2021060234A1 (fr) * 2019-09-27 2021-04-01 株式会社トクヤマ AGENT INHIBANT LA GENERATION DE GAZ RuO4 ET PROCEDE INHIBANT LA GENERATION DE GAZ RuO4
WO2021059666A1 (fr) * 2019-09-27 2021-04-01 株式会社トクヤマ Liquide de traitement pour semi-conducteur de ruthenium et procede de production de celui-ci

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