Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09G—POLISHING COMPOSITIONS; SKI WAXES
  • C09G1/00—Polishing compositions
  • C09G1/02—Polishing compositions containing abrasives or grinding agents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D37/00—Processes of filtration
  • B01D37/02—Precoating the filter medium; Addition of filter aids to the liquid being filtered
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M133/00—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing nitrogen
  • C10M133/02—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing nitrogen having a carbon chain of less than 30 atoms
  • C10M133/04—Amines, e.g. polyalkylene polyamines; Quaternary amines
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D37/00—Processes of filtration
  • B01D37/03—Processes of filtration using flocculating agents
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K13/00—Etching, surface-brightening or pickling compositions
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M135/00—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing sulfur, selenium or tellurium
  • C10M135/02—Sulfurised compounds
  • C10M135/04—Hydrocarbons
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M137/00—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing phosphorus
  • C10M137/12—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing phosphorus having a phosphorus-to-carbon bond
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
  • C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
  • C22B3/42—Treatment or purification of solutions, e.g. obtained by leaching by ion-exchange extraction
• • 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
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F1/00—Etching metallic material by chemical means
  • C23F1/10—Etching compositions
  • C23F1/14—Aqueous compositions
  • C23F1/32—Alkaline compositions
  • C23F1/40—Alkaline compositions for etching other metallic material
• • 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
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F1/00—Etching metallic material by chemical means
  • C23F1/46—Regeneration of etching compositions
• • 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
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F3/00—Brightening metals by chemical means
  • C23F3/04—Heavy metals
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
  • H10P50/60—Wet etching
  • H10P50/64—Wet etching of semiconductor materials
  • H10P50/642—Chemical etching
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
  • H10P50/60—Wet etching
  • H10P50/66—Wet etching of conductive or resistive materials
  • H10P50/663—Wet etching of conductive or resistive materials by chemical means only
  • H10P50/667—Wet etching of conductive or resistive materials by chemical means only by liquid etching only
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
  • H10P50/69—Etching of wafers, substrates or parts of devices using masks for semiconductor materials
  • H10P50/691—Etching of wafers, substrates or parts of devices using masks for semiconductor materials for Group V materials or Group III-V materials
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P52/00—Grinding, lapping or polishing of wafers, substrates or parts of devices
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P52/00—Grinding, lapping or polishing of wafers, substrates or parts of devices
  • H10P52/40—Chemomechanical polishing [CMP]
  • H10P52/402—Chemomechanical polishing [CMP] of semiconductor materials

Definitions

• the present invention relates to a filtration lubricant, a polishing composition, and the like that suppress the reduction of onium salts during filtration in the manufacturing process of semiconductor devices.
• a wiring layer is formed in a semiconductor element for the purpose of extracting electrical signals generated by a transistor to the outside.
• Semiconductor elements are becoming smaller and smaller year by year, and if a material with low electromigration resistance or high resistance is used, the reliability of the semiconductor element will decrease and high-speed operation will be inhibited. Therefore, materials with high electromigration resistance and low resistance are desired as wiring materials.
• tungsten, cobalt, molybdenum, ruthenium, etc. are being considered.
• a process of processing the wiring material is included, and this process uses dry or wet etching.
• the dissolution rate of the wiring material that is, the etching rate is important. If the etching speed is high, the wiring material can be dissolved in a short time, so the number of wafers processed per unit time can be increased.
• RuO 4 - and RuO 4 2- change to RuO 4 in the treatment liquid, and a part of it is gasified and released into the gas phase. Since RuO 4 is strongly oxidizing, it is not only harmful to the human body, but also easily reduced to produce RuO 2 particles. In general, particles pose a serious problem in semiconductor formation processes because they cause a decrease in yield. Therefore, it is very important to suppress the generation of RuO 4 gas.
• Patent Document 1 proposes a processing liquid for semiconductor wafers containing hypobromite ions, which exhibits a good etching rate and stability of the etching rate, and is capable of suppressing the generation of RuO 4 gas.
• a wet etching apparatus for semiconductor wafers is equipped with a fine filter of several nanometers to several tens of nanometers for the purpose of removing particles from the processing solution. It has been found that when onium ions are added to a semiconductor processing solution and the solution is passed through a filter, the onium ion concentration in the solution decreases. It has become clear that this greatly reduces surface roughness during etching and the effect of suppressing RuO 4 gas.
• an object of the present invention is to provide a filtration lubricant that does not reduce the onium ion concentration in the treated liquid by filtration with a filter. Furthermore, it is an object of the present invention to use this filtration lubricant as a semiconductor processing solution to enable etching of wiring materials, especially ruthenium, contained in semiconductor wafers at a sufficient rate, and to etch RuO 4 gas at a sufficient rate. It is an object of the present invention to provide a filtration lubricant that can not only reduce generation but also prevent deterioration of etching properties upon reuse.
• the present inventors conducted extensive studies to solve the above problems. They have also discovered that by controlling the surface tension of the filtration lubricant, it is possible to suppress the decrease in onium ion concentration. As a result, it was possible to maintain the surface smoothness of the wiring material and generate RuO 4 gas. Furthermore, in addition to controlling the surface tension, by appropriately controlling the type and concentration of oxidizing agents that may be included in the filtration lubricant, and the type and concentration of onium ions, the processing liquid containing the filtration lubricant can be The present inventors have discovered that it is possible to suppress the deterioration of etching characteristics during reuse, and have completed the present invention.
• the configuration of the present invention is as follows.
• Item 1 A filtration lubricant containing onium ions and having a surface tension of 60 mN/m or more and 75 mN/m or less at 25°C.
• Item 2 The filtration lubricant according to item 1, 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. It is.
• At least one hydrogen in the aryl group and the ring of the aryl group in the aralkyl group is fluorine, chlorine, an alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, or 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 may be replaced with 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 is chlorine, bromine, fluorine, iodine, or 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 optionally substituted with at least one alkyl group having 1 to 9 carbon atoms, or at least one It may have an alicyclic group which may be substituted with an 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 optionally substituted with at least one alkyl group having 1 to 9 carbon atoms, or at least one alkyl group having 1 to 9 carbon atoms; It is an alicyclic group which may be substituted with ⁇ 9 alkyl groups.
• n is an integer of 1 or 2 and represents 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.
• Item 3 The filtration lubricant according to item 1 or 2, wherein the concentration of the onium ions is 1 mass ppm or more and 10,000 mass ppm or less.
• Item 4 The filtration lubricant according to any one of Items 1 to 3, further comprising 0.001 mol/L or more and 0.20 mol/L or less hypohalite ion.
• Item 5 The filtration lubricant according to any one of Items 1 to 4, further comprising periodate ion.
• the filtration lubricant is used for processing semiconductor wafers, and the semiconductor wafers include Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, Cu, Zr, Item 6.
• Item 7 The filtration lubricant according to any one of Items 1 to 5, wherein the semiconductor wafer contains Ru.
• Item 8 A method for etching a semiconductor wafer, comprising the step of bringing the filtration lubricant according to any one of Items 1 to 7 into contact with the semiconductor wafer.
• Item 9 A method for manufacturing a semiconductor device, comprising the steps of filtering the filtration lubricant according to any one of items 1 to 7, and subjecting the filtered lubricant to etching a semiconductor wafer.
• Item 10 The method for manufacturing a semiconductor device according to item 9, which includes the step of filtering the filtration lubricant a plurality of times.
• Item 11 A method for regenerating a used semiconductor processing liquid, comprising the step of adding the filtration lubricant according to any one of Items 1 to 7 to the used semiconductor processing liquid.
• Item 12 A polishing composition containing at least one selected from the group consisting of onium ions represented by the following formulas (1) to (6) and hypohalite ions.
• 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. It is.
• At least one hydrogen in the aryl group and the ring of the aryl group in the aralkyl group is fluorine, chlorine, an alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, or 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 may be replaced with 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 is chlorine, bromine, fluorine, iodine, or 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 optionally substituted with at least one alkyl group having 1 to 9 carbon atoms, or at least one It may have an alicyclic group which may be substituted with an 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 optionally substituted with at least one alkyl group having 1 to 9 carbon atoms, or at least one alkyl group having 1 to 9 carbon atoms; It is an alicyclic group which may be substituted with ⁇ 9 alkyl groups.
• n is an integer of 1 or 2 and represents 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.
• Item 13 A polishing composition comprising the filtration lubricant according to any one of Items 4 to 7.
• Item 14 A method of supplying a polishing composition to a polishing pad containing abrasive grains or a polishing pad not containing abrasive grains, bringing the surface to be polished of a semiconductor wafer into contact with the polishing pad, and polishing by relative movement between the two.
• Item 15 A metal recovery agent containing an onium ion coordinated to a metal oxide ion or metal hydroxide ion.
• Item 16 The metal recovery agent according to Item 15, wherein the onium ion is one or more selected from phosphonium ions and ammonium ions.
• Item 17 A method for recovering metal from a used semiconductor processing solution, comprising the step of adding the metal recovery agent according to item 15 or 16 to the used semiconductor processing solution.
• the present invention by controlling the surface tension of the filtration lubricant containing the onium salt, it is possible to suppress a decrease in the concentration of the onium salt during the filtration process. Therefore, when this filtration lubricant is used as a semiconductor processing liquid, it is possible to maintain good surface smoothness due to etching and further suppress the generation of RuO 4 gas. Furthermore, since filtration using a fine-mesh filter becomes possible, it is possible to improve the yield of semiconductor wafers by removing particles in the processing liquid. Furthermore, in addition to controlling surface tension, by appropriately controlling the type and concentration of oxidizing agents and onium salts, it is possible to suppress deterioration of etching properties when reusing processing solutions, which can significantly improve semiconductor wafer manufacturing. This makes it possible to reduce costs.
• FIG. 1 is a diagram schematically showing equipment used in an etching process in a method for manufacturing a semiconductor device.
• the filtration lubricant of the present invention is characterized in that it contains onium ions and has a surface tension of 60 mN/m or more and 75 mN/m or less.
• the interaction of onium ions with the metal surface of the semiconductor wafer makes it possible to suppress roughness of the metal surface.
• ruthenium when included in the semiconductor wafer, it interacts with RuO 4 - , RuO 4 2- , etc. generated during ruthenium etching, thereby suppressing the generation of RuO 4 gas and RuO 2 particles that are generated along with it. I can do that. Therefore, the filtration lubricant of the present invention can be suitably used as a semiconductor processing liquid as it is in an etching process, a residue removal process, a cleaning process, a CMP process, etc. in a semiconductor manufacturing process.
• the onium ions contained in the filtration lubricant of the present invention play various roles, but the surface tension of the filtration lubricant is the key to maintaining these effects at a high level.
• the surface tension of the filtration lubricant is less than 60 mN/m, onium ions contained in the filtration lubricant are easily removed during the filtration process, resulting in good surface smoothness and RuO 4 as explained above. It becomes difficult to maintain the gas suppression effect.
• One method for increasing the surface tension is to add a salt containing an anion with a high degree of hydration.
• anions with a high degree of hydration include fluoride ions, chloride ions, and bromide ions.
• the stability of the oxidizing agent may decrease due to the reaction between the salt and the oxidizing agent, and etching may be inhibited due to the high concentration of salt. There is.
• the surface tension is preferably 75 mN/m or less.
• the processing liquid is filtered in order to remove particles from the processing liquid.
• the wiring width is extremely narrow, ranging from several nanometers to several tens of nanometers, so the pore diameter of the filter used in the filtration process is required to be about the same size.
• the smaller the pore size of the filter the easier it is for onium salts or onium ions to be adsorbed and removed. As a result, the onium ion concentration in the processing liquid decreases, and the above-mentioned function as a processing liquid is impaired.
• the surface tension of the filtration lubricant used as the semiconductor processing liquid is around 73 mN/m at 25° C., and by bringing it close to this value, it is possible to suppress adsorption of onium salts or onium ions to the filter.
• the surface tension of the filtration lubricant is controlled to between 60 mN/m and 75 mN/m, adsorption of onium salts or onium ions to the filter is suppressed, and when the filtration lubricant is used as a processing liquid, Can be used without loss of functionality.
• the surface tension is 60 mN/m or more and 75 mN/m or less, preferably 68 mN/m or more and 75 mN/m or less, and most preferably 71 mN/m or more and 73 mN/m or less.
• the surface tension in this specification is a value at 25°C.
• the surface tension of the filtration lubricant can be adjusted, for example, by lowering the concentration of the onium salt added, changing the type of salt containing an anion with a high degree of hydration, or changing the surface tension into an appropriate range. This can be increased, such as by increasing the concentration.
• Surface tension can be adjusted in the same manner in other embodiments described below.
• onium ion Surface tension is influenced by onium ions contained in the filtration lubricant of the present invention. Therefore, by appropriately selecting the type and concentration of onium ions, it is possible to maintain the surface tension within an appropriate range. In order to maintain the surface tension within a preferable range, it is preferable to select at least one type selected from the group consisting of onium ions having the structures shown in formulas (1) to (6) below.
• 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. It is. Furthermore, at least one hydrogen in the aryl group and the ring of the aryl group in the aralkyl group is fluorine, chlorine, an alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, or an alkoxy group having 1 to 9 carbon atoms.
• Counter anions for the above onium ions include fluoride ion, chloride ion, bromide ion, iodide ion, hydroxide ion, nitrate ion, phosphate ion, sulfate ion, hydrogen sulfate ion, methane sulfate ion, and perchloride 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 is chlorine, bromine, fluorine, iodine, or 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 optionally substituted with at least one alkyl group having 1 to 9 carbon atoms, or at least one It may have an alicyclic group which may be substituted with an 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 optionally substituted with at least one alkyl group having 1 to 9 carbon atoms, or at least one alkyl group having 1 to 9 carbon atoms; It is an alicyclic group which may be substituted with ⁇ 9 alkyl groups.
• n is an integer of 1 or 2 and represents 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 hydrocarbon group represented by R in the formula The longer the hydrocarbon group represented by R in the formula, the higher the hydrophobicity. Therefore, the surface tension of the filtration lubricant tends to decrease as the filtration lubricant contains onium ions having a long-chain hydrocarbon group. On the other hand, if the hydrocarbon chain is too short, the effects of onium ions, such as improving surface smoothness and suppressing RuO 4 gas, will be limited. For these reasons, the number of carbon atoms in the hydrocarbon group is preferably within the above range.
• the concentration of onium ions in the filtration lubricant of the present invention is preferably 1 mass ppm or more and 10,000 mass ppm or less. If the amount of onium ions added is too small, when used as a semiconductor processing solution, not only will the interaction with RuO 4 - etc. be weakened and the RuO 4 gas suppressing effect will be reduced, but also the onium ions that adhere to the metal surface during etching will be reduced. Since the amount is insufficient, surface smoothness tends to decrease. On the other hand, if the amount added is too large, an excessive amount of onium ions will be adsorbed onto the metal surface, resulting in a decrease in the etching rate.
• the filtration lubricant of the present invention preferably contains onium ions 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 50 mass ppm or more and 2 ,000 mass ppm or less.
• onium ions when adding onium ions, 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 included, as long as the total concentration of onium ions is within the above concentration range, generation of RuO 4 gas can be effectively suppressed.
• onium ions examples include chlorocholine ion, trans-2-butene 1,4-bis(triphenylphosphonium ion), 1-hexyl-3-methylimidazolium ion, allyltriphenylphosphonium ion, and tetraphenyl ion.
• the effects of onium ions include suppressing surface roughness during etching and suppressing RuO 4 gas, but in addition to this, they also have the effect of increasing the number of reuses when used as a semiconductor processing solution. be.
• the metal In semiconductor wafer manufacturing facilities, it is common to circulate and reuse used processing liquids from the viewpoint of cost reduction.
• the metal begins to dissolve in the processing solution, so the composition of the processing solution differs before and after use. Taking etching of ruthenium with hypobromite ions as an example, ruthenium begins to dissolve as RuO 4 - under alkaline conditions.
• onium ions that can be used for such purposes are preferably phosphonium ions.
• ammonium ions there is a concern that amines may be produced by reaction with hypobromite ions, and this amine may decompose hypobromite ions.
• phosphonium ions generally have a larger molecular size than ammonium ions and easily form ion pairs with RuO 4 - generated by dissolution, so by binding RuO 4 - , RuO 4 - and hypobromine The effect of suppressing reactions with acid ions can also be obtained.
• onium ions examples include allyltriphenylphosphonium ion, tetraphenylphosphonium ion, trans-2-butene-1,4-bis(triphenylphosphonium ion), benzyltriphenylphosphonium ion, tetrabutylphosphonium ion, Examples include tributylhexylphosphonium ion, heptyltriphenylphosphonium ion, cyclopropyltriphenylphosphonium ion, (bromomethyl)triphenylphosphonium ion, (chloromethyl)triphenylphosphonium ion, and the like.
• the filtration lubricant of the present invention may contain an oxidizing agent.
• an oxidizing agent By including an oxidizing agent, it is possible to add the function of removing metals contained in semiconductor wafers, so it can be used as a semiconductor processing liquid as is. Furthermore, it can be suitably used in etching processes, cleaning processes, etc. of semiconductor wafers containing metal.
• the type of oxidizing agent is not particularly limited, but examples include hydrogen peroxide, ozone, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromous acid, bromous acid, bromate acid, perbromate acid, Hypoiodic acid, iodic acid, iodic acid, periodic acid, their salts, and the ions produced when these salts dissociate, as well as hydrogen peroxide, ozone, fluorine, chlorine, bromine, iodine, and permanganate. Salt, chromate, dichromate, and one or more selected from the group consisting of cerium salt.
• hypobromite ion is preferred, and hypochlorite ion is most preferred because of their strong oxidizing power, stability, and suitability for use in semiconductor applications.
• the periodate ion is an orthoperiodate ion or a metaperiodate ion.
• the concentration is not particularly limited as long as it does not depart from the purpose of the present invention, but preferably any Even in the case of 0.001 mol/L or more and 0.20 mol/L or less. If it is less than 0.001 mol/L, the metal etching rate is low and practicality is low. On the other hand, if it exceeds 0.20 mol/L, hypobromite ions tend to decompose, making it difficult to stabilize the metal etching rate.
• the concentration of the hypobromite ion is preferably 0.001 mol/L or more and 0.20 mol/L or less, and 0.005 mol/L or more and 0. It is more preferably .20 mol/L or less, and most preferably 0.01 mol/L or more and 0.10 mol/L or less.
• an oxidizing agent etches metal The mechanism by which an oxidizing agent etches metal will be explained using an example in which the oxidizing agent is hypobromite ion and the metal is ruthenium. It is presumed that hypobromite ions oxidize ruthenium in the filtration lubricant to form RuO 4 , RuO 4 - or RuO 4 2- , which is dissolved in the filtration lubricant. 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 filtration lubricant is preferably alkaline, more preferably the pH of the filtration lubricant is 8 or more and 14 or less; is more preferably 12 or more and 14 or less, and most preferably pH is 12 or more and less than 13. If the pH of the filtration lubricant is 12 or more and less than 13, ruthenium will be dissolved in the filtration lubricant as RuO 4 - or RuO 4 2- , which will greatly reduce the amount of RuO 4 gas generated and RuO 2 Generation of particles can be suppressed.
• the oxidizing agent contained in the filtration lubricant of the present invention may be one type or multiple types. By including multiple types, it may be possible to stabilize the etching rate or improve the stability when reusing the filtration lubricant. For example, when hypobromite ions are included as the first oxidizing agent, the hypobromite ions consumed in etching the metal lose their oxidizing power and change into bromide ions. In this case, the greater the amount converted to bromide ions, the lower the etching rate when used as a semiconductor processing solution.
• the filtration lubricant contains multiple types of oxidizing agents, for example, if it contains hypochlorite ions in addition to hypobromite ions, the bromide ions that have lost their oxidizing power will When oxidized by ions, it changes to hypobromite ions. Therefore, it is possible to suppress a decrease in the hypobromite ion concentration in the filtration lubricant, and even when the filtration lubricant is reused, the etching rate is less likely to decrease.
• the filtration lubricant of the present invention contains hypobromite ions
• the concentration of hypochlorite ion is not limited as long as it does not depart from the spirit of the present invention, but it is preferably 0.001 mol/l or more and 0.2 mol/l or less. If the concentration of hypochlorite ions is less than 0.001 mol/l, Br ⁇ cannot be efficiently oxidized, and the etching rate of ruthenium decreases.
• hypochlorite ion added if the amount of hypochlorite ion added is greater than 0.2 mol/l, the stability of hypochlorite ion will decrease, and the It is not suitable because it promotes the decomposition of bromate ions.
• concentration of hypochlorite ion is more preferably 0.005 mol/l or more and 0.10 mol/l or less, most preferably 0.01 mol/l or more and 0.05 mol/l or less.
• the filtration lubricant of the present invention may contain other additives conventionally used in semiconductor processing liquids within a range that does not impair the object of the present invention.
• other additives include acids, metal anticorrosive agents, water-soluble organic solvents, fluorine compounds, oxidizing agents, reducing agents, complexing agents, chelating agents, surfactants, antifoaming agents, pH adjusters, and stabilizing agents. etc. can be added. These additives may be added alone or in combination.
• An acid or alkali can be added to the filtration lubricant to adjust the pH of the filtration lubricant.
• the alkali it is preferable to use an organic alkali because it does not contain metal ions that cause problems in semiconductor manufacturing.
• the organic alkali is preferably tetraalkylammonium hydroxide, and tetramethylammonium hydroxide is preferable because it has a large number of hydroxide ions per unit weight and high purity products are easily available. It is more preferable.
• the filtration lubricant of the present invention may contain alkali metal ions, alkaline earth metal ions, etc. .
• the metal content in the filtration lubricant of the present invention is , specifically, any metal selected from, for example, lithium, sodium, potassium, aluminum, magnesium, calcium, chromium, manganese, iron, nickel, cobalt, copper, silver, cadmium, barium, zinc, and lead.
• the content of any one metal selected from iron, copper, and zinc is preferably 0.01 ppt or more and 1 ppb or less, more preferably 0.01 ppt or more and 0.5 ppb or less. It is preferably 0.01 ppt or more and 0.2 ppb or less, and most preferably 0.01 ppt or more and 0.1 ppb or less.
• ionic metals were mentioned above as metals that may be included in the filtration lubricant of the present invention, the present invention is not limited to this, and nonionic metals (particulate metals) may also be included.
• a particulate metal is contained alone, its concentration is preferably within the above range.
• ionic metals and particulate metals it is preferable that the total is within the above range.
• the water contained in the filtration lubricant of the present invention is preferably water from which metal ions, organic impurities, particles, etc. have been removed by distillation, ion exchange treatment, filter treatment, various adsorption treatments, etc., and especially pure water, ultra-high-quality water, etc. Pure water is preferred.
• Such water can be obtained by known methods widely used in semiconductor manufacturing.
• the filtration lubricant of the present invention is preferably stored at low temperatures and/or protected from light. By storing at low temperature and/or shielded from light, it can be expected to have the effect of suppressing the decomposition of oxidizing agents, onium ions, etc. in the filtration lubricant. Furthermore, the stability of the filtration lubricant can be maintained by storing the filtration lubricant in a container filled with inert gas to prevent carbon dioxide from being mixed in. Further, the inner surface of the container, that is, the surface that comes into contact with the filtration lubricant, is preferably formed of glass or an organic polymer material.
• the filtration lubricant of the present invention is a chemical solution that reduces the capture of onium salts by a filter in the filtration process included in the manufacturing method of semiconductor devices. It can also be said to be a reducing agent.
• Semiconductor wafers to which the filtration lubricant of the present invention is used in semiconductor processing preferably include Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, At least one metal selected from Cu, Zr, La, Mo, and W is included. These metals are deposited on semiconductor wafers by methods widely known in semiconductor manufacturing processes, such as CVD, ALD, PVD, sputtering, and plating. Since the filtration lubricant of the present invention contains onium ions and has the effect of suppressing RuO 4 gas, it can be particularly suitably used for ruthenium among these metals.
• Ruthenium is not limited to metallic ruthenium, and may include ruthenium alloys, ruthenium oxides (ruthenium dioxide, diruthenium trioxide, etc.), nitrides, oxynitrides, intermetallic compounds, Also includes ionic compounds, complexes, etc.
• the filtration lubricant of the present invention can etch a semiconductor wafer by bringing it into contact with the semiconductor wafer. That is, the semiconductor wafer etching method of the present invention includes the step of bringing the filtration lubricant into contact with the semiconductor wafer.
• the filtration lubricant of the present invention can be used as it is as a semiconductor processing solution, and when it contains the oxidizing agent described above, it can be preferably used as an etching solution for semiconductor wafers.
• a filtration lubricant is used as an etching solution, the conditions described above can be applied to the type of oxidizing agent and the concentration of the oxidizing agent in the filtration lubricant.
• a ruthenium wet etching process using the filtration lubricant of the present invention will be explained as an example.
• a base made of a semiconductor for example, Si
• the prepared base is subjected to oxidation treatment to form a silicon oxide film on the base.
• an interlayer insulating film made of a low dielectric constant (Low-k) film is formed, and via holes are formed at predetermined intervals.
• a ruthenium film is formed by thermal CVD.
• the temperature at which ruthenium is etched using the filtration lubricant of the present invention as a semiconductor processing solution is not particularly limited, but may be determined by taking into consideration the etching rate of ruthenium, the amount of RuO 4 gas generated, and the like. When the processing temperature is high, the amount of RuO 4 gas increases and the stability of hypobromite ions also decreases. On the other hand, the etching rate tends to decrease as the temperature decreases. For these reasons, the temperature at which ruthenium is etched is preferably 10°C to 90°C, more preferably 15°C to 60°C, and most preferably 25°C to 45°C.
• the method for manufacturing a semiconductor device of the present invention includes a step of filtering the above-mentioned filtering lubricant, and a step of using the filtered lubricant for etching a semiconductor wafer.
• the filtration lubricant of the present invention can be used as it is in the manufacturing method of semiconductor devices. Further, as for the etching process, the conditions explained above can be applied as they are. The metal to be etched can also be the same as above. In order to perform etching of semiconductor wafers, it is preferable that the filtration lubricant contains the above-mentioned oxidizing agent.
• the conditions explained above can be applied to the type of oxidizing agent and the concentration of the oxidizing agent in the filtration lubricant. Further, the surface tension of the filtration lubricant at 25° C. is 60 mN/m or more and 75 mN/m or less, and the preferable range is the same as the conditions described above. Furthermore, the contents explained above can also be applied to other conditions of the filtration lubricant.
• a filtration lubricant passes through filters 1 and 2 or 3 during the manufacture of semiconductor devices.
• the valve 10 in FIG. 1 is closed and the valve 9 is opened, the chemical solution in the chemical cabinet 6 is filtered by passing through the filters 1 and 2 by driving the pump 4.
• a filtration step of passing the chemical solution through the filters 1 and 2 may be performed multiple times.
• the number of filters to be passed during one filtration step can be, for example, 1 or more, and may be 2, 3, or 4 or more.
• the chemical solution in the chemical cabinet 6 is supplied to the etching table 8 by driving the pump 4, and the semiconductor wafer is etched. Further, in order to replenish the chemical solution in the chemical cabinet 6, the chemical solution in the chemical solution replenishment unit passes through the filter 3 and is replenished into the chemical cabinet 6 by driving the pump 5.
• the chemical liquid described here may be a filtration lubricant itself, or may be a chemical liquid obtained by adding a filtration lubricant to a chemical liquid other than the filtration lubricant. When adding a filtration lubricant to a chemical liquid other than the filtration lubricant, the surface tension of the mixed chemical liquid is adjusted to the range described above.
• the method for manufacturing a semiconductor device includes a known process used in a method for manufacturing a semiconductor device, such as one or more steps selected from a wafer fabrication process, an oxide film formation process, a transistor formation process, a wiring formation process, and a CMP process. May include. Further, the method for manufacturing a semiconductor device of the present invention may include as one step a method for recovering metal from a used semiconductor processing solution, which will be described later.
• the method for manufacturing a semiconductor element of the present invention includes a step of recovering a processing solution after etching a semiconductor wafer, a step of adding a metal recovery agent to be described later to the recovered processing solution, and a step of adding a metal recovery agent to the recovered processing solution.
• the manufacturing method may include a step of filtering the treatment liquid to which the metal is added, so that the metal in the treatment liquid is recovered.
• a method of making a filtration lubricant is provided.
• the method for producing a filtration lubricant at least onium ions and water are mixed and adjusted so that the surface tension at 25°C is 60 mN/m or more and 75 mN/m or less (25°C).
• the conditions regarding the type and concentration of onium ions used in the filtration lubricant listed above can be applied as they are.
• the surface tension of a solution containing onium ions and water can be adjusted, for example, by adjusting the type and concentration of onium ions.
• the range explained above can be applied as is.
• an oxidizing agent it may be added at the time of mixing onium ions and water, or it may be added to a solution in which onium ions and water are mixed in advance.
• the conditions explained above can be applied as they are.
• the conditions explained above can also be applied to conditions such as other additives contained in the filtration lubricant.
• Another embodiment of the present invention includes a step of adding the above-described filtration lubricant to a used semiconductor processing liquid (hereinafter also simply referred to as a regeneration method).
• used semiconductor processing liquid is recycled.
• the used semiconductor processing liquid here refers to a chemical liquid that has been used for etching or other processing at least once in the manufacture of semiconductor wafers, for example. Therefore, the used semiconductor processing liquid may contain an oxidizing agent. Examples of the oxidizing agent include those mentioned in the explanation of the filtration lubricant. Further, the surface tension at 25° C.
• the concentration of onium ions contained in the filtration lubricant to be added may be adjusted.
• the concentration of onium ions in the filtration lubricant to be added so that the concentration of onium ions contained in the regenerated chemical solution falls within the range described for the filtration lubricant above.
• the polishing composition of the present invention is characterized by containing one or more onium ions selected from the group consisting of onium ions represented by the following formulas (1) to (6), but is not limited thereto, Semiconductor wafers containing metal or metal oxides can be polished flat and smooth while maintaining a high polishing rate.
• 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. It is. Furthermore, at least one hydrogen in the aryl group and the ring of the aryl group in the aralkyl group is fluorine, chlorine, an alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, or an alkoxy group having 1 to 9 carbon atoms.
• Counter anions for the above onium ions include fluoride ion, chloride ion, bromide ion, iodide ion, hydroxide ion, nitrate ion, phosphate ion, sulfate ion, hydrogen sulfate ion, methane sulfate ion, and perchloride 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 is chlorine, bromine, fluorine, iodine, or 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 optionally substituted with at least one alkyl group having 1 to 9 carbon atoms, or at least one It may have an alicyclic group which may be substituted with an 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 optionally substituted with at least one alkyl group having 1 to 9 carbon atoms, or at least one alkyl group having 1 to 9 carbon atoms; It is an alicyclic group which may be substituted with ⁇ 9 alkyl groups.
• n is an integer of 1 or 2 and represents 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 onium ions generated by dissociation of the onium ions interact with the metal or metal oxide to be polished, resulting in a smooth polished surface.
• onium ions include the compounds described in the above-mentioned filtration lubricant of the present invention, and the preferred range of the onium ion concentration is also the same.
• the surface tension of the polishing composition of the present invention at 25° C. may be 60 mN/m or more and 75 mN/m or less.
• the surface tension at 25° C. of the polishing composition may be 68 mN/m or more and 75 mN/m or less, or 71 mN/m or more and 73 mN/m or less. When the surface tension of the polishing composition is within these ranges, a sufficient polishing rate can be obtained for the object to be polished, and it is also possible to finish the surface of the object to be polished in a preferable state.
• the polishing composition of the present invention may contain an oxidizing agent.
• the oxidizing agent is not particularly limited, but when polishing materials with high hardness and high chemical stability, in order to obtain a sufficiently high polishing rate, it is necessary to use hypohalite ions with high oxidizing power, especially hypochlorite. It is preferable to select chlorate ion, hypobromite ion, etc.
• the counter ion (cation) is preferably a quaternary ammonium ion such as a tetramethylammonium ion because it can suppress the metal content.
• the concentration is not particularly limited, but if it is too thin, the polishing rate will decrease, and if it is too thick, changes in concentration due to decomposition of hypohalite ions will increase.
• the concentration of hypohalite ions is preferably 0.001 mol/L or more and 0.20 mol/L or less, and 0.005 mol/L. It is more preferably 0.20 mol/L or more, and most preferably 0.01 mol/L or more and 0.10 mol/L or less.
• the same concentration range can also be applied when the hypohalite ion is one or more selected from hypochlorite ions and hypobromite ions.
• each concentration of halogen acid ions, halogen acid ions, and halide ions generated due to consumption of hypohalite ions during polishing or natural decomposition during storage etc. is 0.00001 mol/L or more and 0.10 mol/L or less, respectively. It is preferably 0.00001 mol/L or more and 0.02 mol/L or less, and most preferably 0.00001 mol/L or more and 0.01 mol/L or less.
• the pH of the polishing composition of the present invention is preferably 7 or more and 14 or less from the viewpoint of polishing properties and stability. If it is less than 7, the polishing rate may decrease and become unstable. For example, when hypohalite ions are included as an oxidizing agent, decomposition of the hypohalite ions occurs at a pH of less than 7. In addition, if the pH is less than 7, metal-containing particles may easily remain on the surface of the semiconductor wafer, and the amount of metal remaining on the wafer after polishing tends to increase.From this point of view, it is preferable that the pH is 7 or more. . Further, when colloidal silica is used as the abrasive grain, the colloidal silica may dissolve at pH 13 or higher. For these reasons, the pH is preferably 7 or more and 14 or less, more preferably 9 or more and 13 or less, and most preferably 11 or more and 12.5 or less.
• abrasive grains When the polishing composition of the present invention contains abrasive grains, known abrasive grains can be used without particular limitation.
• Preferred abrasive grains include silicon oxide (silica) particles, diamond particles, cerium oxide (ceria) particles, aluminum oxide (alumina) particles, zirconium oxide (zirconia) particles, and titanium oxide (titania) particles.
• concentration of these abrasives is not particularly limited, but if it is too thin, the polishing speed will decrease, and if it is too thick, the abrasive grains will aggregate and cause deterioration of the surface smoothness, so it should be 0.02 to 10.0 mass. %, more preferably 0.5 to 5.0% by weight.
• polishing method The polishing method using the polishing composition of the present invention can be carried out using a single-sided or double-sided polisher.
• An example of a polishing device includes a rotary table that fixes a surface plate, a wafer holder that holds a semiconductor wafer to be polished, and a rotating wafer that presses the held wafer against the polishing surface of the surface plate with a predetermined polishing load. It is possible to use a polishing device equipped with a pressurizing section having a rotating mechanism for this purpose.
• the polishing composition of the present invention with abrasive particles added thereto is applied, sprinkled, or dropped on a semiconductor wafer to be polished, and brought into contact with a polishing pad (sheet) that does not contain abrasive particles, resulting in relative movement between the two.
• the method of polishing involves applying, spraying, or dropping the polishing composition of the present invention onto a semiconductor wafer to be polished, bringing it into contact with a polishing pad (sheet) on which polishing particles are fixed, and polishing by relative movement between the two. It can be polished by other methods.
• Semiconductor wafers polished using the polishing liquid of the present invention can be polished using, for example, Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, Cu, Zr, La, Mo. , W, etc.
• the polishing composition of the present invention may contain a lubricant, a viscosity imparting agent, a viscosity modifier, a rust preventive, and the like as appropriate, as long as it does not go against the spirit of the present invention.
• a lubricant for example, it can be prepared by mixing abrasive grains (silica), an oxidizing agent (hypobromite ion), a pH adjuster (tetramethylammonium hydroxide), and ultrapure water.
• the metal recovery agent of the present invention is characterized in that it contains one or more onium ions selected from onium ions coordinating to metal oxide ions and metal hydroxide ions.
• onium ions selected from onium ions coordinating to metal oxide ions and metal hydroxide ions.
• the onium ion that coordinates with the metal oxide ion or metal hydroxide ion is preferably a phosphonium ion, a sulfonium ion, or an ammonium ion, and a phosphonium ion or ammonium ion that forms a stable ion complex with the metal oxide ion is preferable. More preferred. More specifically, any one or more selected from the group consisting of onium ions represented by formulas (1) to (6) explained in the section of filtration lubricants can be used.
• the metal oxide ion or metal hydroxide ion is a metal oxide or metal hydroxide ion that has a negative charge in the solution.
• oxide ions or hydroxide ions of Ru, Ta, Co, Cr, Os, Ni, Mn, Cu, Zr, Mo, and W are oxide ions or hydroxide ions of Ru, Ta, Co, Cr, Os, Ni, Mn, Cu, Zr, Mo, and W.
• onium ions By adding onium ions to a solution containing these ions, an ion complex is formed with the metal oxide ion or metal hydroxide ion, producing an insoluble salt.
• onium ions as those explained for the filtration lubricant can be used.
• the types of counter ions to the onium ion can also be the same as those explained for the filtration lubricant.
• the metal recovery agent preferably contains onium ions at a concentration of, for example, 1 mass ppm or more and 50 mass % or less, more preferably 10 mass ppm or more and 10 mass % or less, and 50 mass ppm or more and 10,000 mass ppm or more. It is more preferably contained at a concentration of 100 ppm or more and 5,000 ppm or less by mass, most preferably at a concentration of 100 ppm or more and 5,000 ppm or less. This concentration range can be similarly applied when the onium ion is one or more selected from the group consisting of onium ions represented by formulas (1) to (6).
• the surface tension of the metal recovery agent at 25° C. may be 60 mN/m or more and 75 mN/m or less.
• the surface tension at 25° C. of the polishing composition may be 68 mN/m or more and 75 mN/m or less, or 71 mN/m or more and 73 mN/m or less.
• the surface tension of the metal recovery agent is within these ranges, it becomes possible to use the used metal recovery agent after metal recovery by filtration or the like as a metal recovery agent again.
• Another embodiment of the present invention is a method for recovering metal from a used semiconductor processing solution (hereinafter also simply referred to as a recovery method), which includes a step of adding the metal recovery agent described above to the used semiconductor processing solution.
• the recovery method of the present invention is aimed at recovering metals from used semiconductor processing solutions.
• the used semiconductor processing liquid here refers to a chemical liquid that has been used for etching or other processing at least once in the manufacture of semiconductor wafers, for example. Therefore, the used semiconductor processing liquid may contain an oxidizing agent. Examples of the oxidizing agent include those mentioned in the explanation of the filtration lubricant.
• a metal recovery agent By adding a metal recovery agent to the used semiconductor processing solution, an insoluble salt containing metal is precipitated, and the metal can be recovered by passing through a step of filtering this.
• a filter used for metal filtration it is preferable to use, for example, a filter made of an organic polymer material or an inorganic material.
• filtration filters made of polyolefin (polypropylene, polyethylene, ultra-high molecular weight polyethylene), polysulfone, cellulose acetate, polyimide, polystyrene, fluororesin, and/or quartz fiber can be used.
• the fluororesin is not particularly limited as long as it is a resin (polymer) containing fluorine atoms, and any known fluororesin can be used.
• examples include trifluoroethylene-ethylene copolymers and perfluoro(butenyl vinyl ether) cyclized polymers.
• the pore size of the filtration filter is not particularly limited, a filtration filter with a pore size of 1 ⁇ m or more or a precision filtration filter can be used to remove coarse particles.
• a microfiltration filter, an ultrafiltration filter, or a nanofiltration membrane with a pore size of 0.001 ⁇ m or more and less than 1 ⁇ m can be used to remove fine particles.
• a semiconductor device manufacturing method includes the above-mentioned recovery method as a series of steps, for example, a step of recovering a used semiconductor processing solution, a step of adding a metal recovery agent to the recovered processing solution, and a step of adding a metal recovery agent to the recovered processing solution are performed. This may be combined with the step of filtering the added used semiconductor processing liquid. It is also possible to add a metal recovery agent to the semiconductor processing solution in advance, precipitate insoluble salts containing metals in the used semiconductor processing solution, and recover them in the subsequent filtration step. In these cases, it is also possible to reuse the used semiconductor processing liquid after metal recovery as a semiconductor processing liquid.
• the salt of metal oxide ions or metal hydroxide ions and onium ions recovered by the filtration filter can be eluted into a solvent by passing a solvent that can dissolve the salt through the filtration filter.
• Solvents that can dissolve the salt include, but are not limited to, water, acids, alkalis, alcohols, ethers, ketones, nitriles, amines, amides, carboxylic acids, and aldehydes. isn't it.
• solvents examples include hydrochloric acid, sulfuric acid, nitric acid, aqueous ammonia, tetramethylammonium hydroxide, ethyltrimethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, methanol, and ethanol.
• a piece of ruthenium membrane measuring 10 x 20 mm was immersed in the filtration lubricant for 1 minute at 30°C. After the etching process, the sheet resistance was similarly measured using a four-probe resistance measuring device and converted into film thickness, which was defined as the ruthenium film thickness after the etching process.
• the etching rate was calculated by dividing the amount of change in film thickness before and after the treatment by the immersion time, and evaluated based on the following criteria. In all cases, ratings A to C are acceptable, and rating D is unacceptable. A: >50 ⁇ /min B: 50 to 20 ⁇ /min C: Less than 20 ⁇ /min to 10 ⁇ /min (acceptable level) D: Etching not possible
• the amount of RuO 4 gas generated was measured using ICP-OES. Put 5 mL of the filtration lubricant obtained above into a closed container, and soak one 10 x 20 mm ruthenium film with a 1200 ⁇ thick ruthenium film at 30°C until all the ruthenium is dissolved. I let it happen. Thereafter, air was flowed into the sealed container, and the gas phase in the sealed container was bubbled into a container containing an absorption liquid (1 mol/L NaOH), so that the RuO 4 gas generated during immersion was trapped in the absorption liquid.
• an absorption liquid (1 mol/L NaOH
• the ruthenium surface before and after etching was observed using a field emission scanning electron microscope (JSM-7800F Prime, manufactured by JEOL Ltd.) to confirm the presence or absence of surface roughness, and evaluated based on the following criteria.
• the surface roughness is ranked A to D in descending order of surface roughness, with ratings A to C being acceptable levels and ratings D being unacceptable levels.
• D Roughness is observed on the entire surface and the roughness is deep
• etching rate 2 was similarly evaluated.
• the stability of the etching rate when the filtration lubricant was reused was defined as etching rate 2 divided by etching rate 1, and was evaluated based on the following criteria. If etching rate 1 and etching rate 2 do not change, it means that the performance of the filtration lubricant after reuse is maintained. Furthermore, even if there is a change, ratings A to C are at an acceptable level, and rating D is an unacceptable level.
• hypobromite ion and hypochlorite ion concentration The hypobromite ion and hypochlorite ion concentrations were measured using an ultraviolet-visible spectrophotometer (UV-2600, manufactured by Shimadzu Corporation). A calibration curve was created using an aqueous solution of hypobromite ion and hypochlorite ion with known concentrations, and the concentrations of hypobromite ion and hypochlorite ion in the produced filtration lubricant were determined. The hypobromite ion concentration was determined from measurement data when the absorption spectrum stabilized after mixing the bromine-containing compound, oxidizing agent, and basic compound.
• thermometer protection tube manufactured by Cosmos Bead, bottom sealed type
• a magnetic stirrer manufactured by AsOne, C-MAG HS10
• AsOne C-MAG HS10
• the flask was rotated and stirred at 300 rpm.
• chlorine gas manufactured by Fujiox, with specified purity
• Table 1 shows the composition of the treatment liquid (filtration lubricant) and the results of each evaluation.
• the onium salt concentration significantly decreased due to the filtration process, and the surface smoothness was unacceptable, so the etching rate, surface smoothness, RuO 4 gas amount, It was not possible to satisfy all of the stability requirements.
• the filtration lubricant of this example satisfied all of these evaluation items.
• the stability of the treated liquid during reuse was improved due to the effect of adding hypochlorite ion or phosphonium salt to the filtration lubricant.
• Comparative Example 3 in which a phosphonium salt was also added, the surface tension was low and the phosphonium salt was removed by filtration, so no improvement in stability was observed.
• Examples 16 to 18 First, an oxide film was formed on a silicon wafer using a batch type thermal oxidation furnace, and a ruthenium film of 1200 ⁇ ( ⁇ 10%) was formed thereon using a sputtering method. Next, 1800 g of colloidal silica (average particle size 80 nm, SiO 2 content 50%) and 2200 g of ultrapure water were added to 1000 g of a solution having the same composition as in Examples 10 to 12 to obtain a polishing composition. The surface tensions of the polishing compositions were 68, 68, and 68 mN/m, respectively. Thereafter, the ruthenium film-formed surface was polished using the prepared polishing composition under the following conditions.
• Polishing machine EJ-380IN manufactured by Engis Polishing pressure: 500gf/ cm2 Polishing pad: SUBA-800 Nittahas Co., Ltd.
• Surface plate rotation speed 120 rpm
• Supply amount of polishing composition 50ml/min
• Polishing time 10 minutes
• the sheet resistance was measured using a four-probe resistance measuring device (Loresta-GP, manufactured by Mitsubishi Chemical Analytic Corporation) and converted into film thickness, and the polishing rate of ruthenium was calculated.
• the polishing rate for ruthenium-containing wafers was 10 nm/min, which revealed that a sufficient polishing rate could be obtained. Further, when the polished surface was observed by SEM, it was confirmed that good surface smoothness was obtained.
• Example 19 A treatment solution containing hypobromite ions was prepared in the same manner as in Example 1 so as to have the composition shown in Table 2.
• a 10 ⁇ 10 mm ruthenium film piece with a 1200 ⁇ thick ruthenium film formed thereon was immersed in the obtained treatment solution until the ruthenium film was completely dissolved.
• a metal recovery agent having the composition shown in Table 2 was added to the treatment solution in which the ruthenium film was dissolved.
• the treatment solution containing the metal recovery agent was passed through a "Fluoroguard ATX filter (pore size: 0.05 ⁇ m)" made of polytetrafluoroethylene manufactured by Nippon Entegris.
• the onium ion concentration in the treated solution after filtration was measured in the same manner as in the above-mentioned "Evaluation of the residual rate of onium ions after filtration.” Further, the ruthenium concentration in the treated solution after filtration was measured by ICP-OES (iCAP6500 DUO, manufactured by Thermo Fisher Scientific).
• Example 4 A treatment solution after filtration was prepared in the same manner as in Example 19 except that no metal recovery agent was added to the treatment solution.
• the ruthenium concentration in the treated solution after filtration was measured by ICP-OES (iCAP6500 DUO, manufactured by Thermo Fisher Scientific).

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• 2023
  • 2023-03-30 JP JP2024512854A patent/JPWO2023190984A1/ja active Pending
  • 2023-03-30 US US18/852,780 patent/US20250235805A1/en active Pending
  • 2023-03-30 TW TW112112285A patent/TW202340532A/zh unknown
  • 2023-03-30 WO PCT/JP2023/013385 patent/WO2023190984A1/ja not_active Ceased
  • 2023-03-30 EP EP23780992.6A patent/EP4506982A4/en active Pending
  • 2023-03-30 KR KR1020247033245A patent/KR20240169635A/ko active Pending
  • 2023-03-30 CN CN202380031866.6A patent/CN118974895A/zh active Pending

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