Classifications

• • 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
• • 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
  • C23F1/10—Etching compositions
  • C23F1/14—Aqueous compositions
  • C23F1/32—Alkaline compositions
  • C23F1/38—Alkaline compositions for etching refractory metals

Definitions

• the present invention relates to a processing liquid for a semiconductor wafer. More specifically, the present invention relates to a processing liquid for a semiconductor wafer, which has a sufficient etching rate for a metal used for a wiring layer of a semiconductor element and can suppress roughening of the metal surface due to etching.
• the wiring layer plays an important role of outputting an electric signal from a transistor to the outside.
• the design rules for semiconductor devices have been miniaturized, and the wiring resistance tends to increase.
• the high-speed operation of the semiconductor element is hindered, and countermeasures are required. Therefore, as the wiring material, a wiring material having higher electromigration resistance and a reduced resistance value than the conventional wiring material is desired.
• ruthenium Compared to conventional wiring materials such as aluminum and copper, ruthenium has high electromigration resistance and can reduce the resistance value of wiring, so it is particularly noteworthy as a wiring material with a semiconductor element design rule of 10 nm or less. Has been done. In addition to wiring materials, ruthenium can prevent electromigration even when copper is used as the wiring material, so it is also being considered to use ruthenium as a barrier metal for copper wiring. ..
• the wiring is formed by dry etching or wet etching as in the conventional wiring material.
• dry etching of ruthenium in-plane non-uniformity due to plasma distribution occurs, and the etching rate increases or decreases depending on the reaction species and the flux or energy of ions, which makes precision etching difficult and difficult.
• etching is hindered by the strong adhesion of Ru ⁇ 2 , which is a reaction product, to the wall surface of the pattern. Therefore, wet etching is attracting attention as a method for etching ruthenium more precisely.
• etch-back process is required to suppress the decrease in yield due to the above. That is, since the surface roughness generated by the etching of the metal forming the wiring layer increases the contact resistance between the wiring layers, the etching process that suppresses the roughness of the metal surface is regarded as one of the most important items.
• the melting rate of the metal that is, the etching rate is also important, and there is a demand for a processing liquid for semiconductors having a sufficient etching rate for the metal and less surface roughness after etching. There is.
• Patent Document 1 As a method for etching a ruthenium film, pH 12 or higher and a standard redox potential of 300 mV vs. A method of etching a ruthenium film using a chemical solution containing SHE (standard hydrogen electrode) or higher, specifically, a solution containing a halogen oxygen salt such as hypochlorite, chlorite or bromate. Proposed. Further, Patent Document 2 proposes a cleaning method for oxidizing, dissolving and removing ruthenium by using a removing solution in which a strong acid such as nitric acid is further added to cerium (IV) ammonium nitrate.
• a strong acid such as nitric acid is further added to cerium (IV) ammonium nitrate.
• Patent Document 3 has ruthenium as a treatment liquid used for etching a metal in a semiconductor wafer, which contains hypochlorite ion and a solvent and has a pH of more than 7 and less than 12.0 at 25 ° C. Wafer processing solutions have been proposed.
• the treatment liquids described in Patent Documents 1 to 3 contain an oxidizing agent for ruthenium and are removed by oxidizing ruthenium. These treatment liquids can remove ruthenium at a high etching rate, and are particularly useful for removing metals such as ruthenium adhering to the end face portion (bevel) and the back surface portion of a semiconductor wafer. Is.
• the present inventors have focused on the ion species contained in the treatment liquid containing the hypochlorite ion, and have focused on the hypochlorite ion and the hypochlorite ion.
• the etching rate can be controlled to 20 ⁇ / min or less, and the storage stability and etching rate of hypochlorite ion can be controlled. It has been found that precise control and surface roughness after etching can be suppressed (see Patent Document 4).
• the treatment liquid described in Patent Document 4 it is possible to perform etching while suppressing surface roughness after etching, and the treatment liquid is suitable for the etch back process.
• the treatment liquid has a very low etching rate and has a high etching rate, and there is still room for improvement in that surface roughness after etching is suppressed.
• an object of the present invention is to provide a processing liquid for a semiconductor wafer, which has a sufficient etching rate for a metal used for a wiring layer of a semiconductor element and can suppress metal surface roughness due to etching. ..
• the present inventors have conducted diligent studies to solve the above problems.
• the configuration of the present invention is as follows.
• Item 1 A processing liquid for semiconductor wafers.
• the treatment liquid contains at least one hypohalogenate ion and Containing at least one anionic species selected from halogenate ions, subhalogenates, and halide ions.
• Item 2 The processing liquid for a semiconductor wafer according to Item 1, which contains two or more types of anions as the anion species.
• Item 5 The treatment liquid for a semiconductor wafer according to any one of Items 1 to 4, which contains at least one selected from hypochlorite ion and hypobromous acid ion as the hypohalogenate ion.
• the treatment liquid for a semiconductor wafer according to Item 5 which contains hypochlorite ion and hypobromous acid ion as the hypohalogenate ion.
• the hypobromous acid ion contains at least hypobromous acid ion, and the content of the hypobromous acid ion is 0.0010 mol / L or more and 0.20 mol / L or less with respect to the treatment liquid.
• Item 3. The processing liquid for a semiconductor wafer according to any one of Items 1 to 6.
• the semiconductor wafer contains at least one metal selected from Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, Cu, Zr, La, Mo, and W.
• Item 11 A step of preparing a first solution containing at least one anion species selected from a halogenate ion, a subhalogenate ion, and a halide ion.
• a step of preparing a second solution containing hypohalogenate ions, and a step of mixing the first solution and the second solution are included.
• Item 15 The method for producing a processing liquid for a semiconductor wafer according to Item 14, wherein the first solution and the second solution each contain onium ions.
• Item 16 A kit for preparing a treatment liquid for a semiconductor wafer, which comprises a first solution containing at least one anion species selected from a halide ion, a hypohalite ion, and a halide ion, and a hypothesis.
• a kit comprising at least a second solution containing halide ions.
• kits according to Item 16 wherein the oxidizing power of the hypohalogenate ion contained in the second solution is higher than the oxidizing power of the anionic species contained in the first solution.
• Item 18 The item 16 or 17, wherein at least one of the anion species contained in the first solution is a bromide ion, and the hypochlorite ion contained in the second solution is a hypochlorite ion. kit.
• the processing liquid for a semiconductor wafer of the present invention maintains a sufficient etching rate for metals used in the wiring layer of semiconductor elements, particularly ruthenium, suppresses surface roughness due to etching, and further improves the stability of the treatment liquid. It is possible.
• the treatment liquid for the semiconductor wafer of the present invention (hereinafter, also simply referred to as “treatment liquid”) is selected from at least one hypohalogenate ion and at least one selected from halogenate ion, subhalogenate ion, and halide ion. It is characterized in that the content of at least one anion species including the anion species of the species is 0.30 mol / L to 6.00 mol / L.
• the processing liquid for a semiconductor wafer of the present invention can maintain a sufficient etching rate for ruthenium and the like, and can suppress surface roughness due to etching.
• the notation "A to B" for the numerical values A and B means “A or more and B or less”.
• the unit shall be applied to the numerical value A as well.
• the present inventors speculate as to the reason why the processing liquid for the semiconductor wafer of the present invention maintains a sufficient etching rate for ruthenium and suppresses surface roughness due to etching as follows. That is, when a treatment solution containing hypohalogenate ions is used as an etching solution for ruthenium, for example, when hypochlorite ions are used, it is presumed that ruthenium is oxidized and removed by the following reaction. (Equation 1). 2Ru + 7ClO- + H 2O ⁇ 2RuO 4- + 7Cl- + 2H + (Equation 1)
• the treatment liquid of the present invention is characterized in that it contains a specific amount of anion species selected from halogenate ions, subhalogenate ions, and halide ions in addition to hypohalogenate ions. Since these anionic species are presumed to be present even on the ruthenium surface to some extent in the treatment liquid, it is presumed that it is possible to control the ruthenium etching rate by hypohalogenate ions to some extent. Ru. It is presumed that the surface roughness due to etching can be suppressed by reducing the etching rate of ruthenium.
• hypohalogenate ions decrease in concentration in the treatment liquid due to the following disproportionation reaction (Equation 2). 2ClO- ⁇ ClO 2- + Cl- ( Equation 2)
• the treatment liquid of the present invention contains a specific amount of anionic species selected from halogenate ions, phobic acid ions, and halide ions, the reaction between the hypohalite ions is inhibited.
• anionic species selected from halogenate ions, phobic acid ions, and halide ions
• the reaction between the hypohalite ions is inhibited.
• the decrease in the hypohydranoic acid ion content is suppressed, and therefore, it is presumed that a high etching rate and good stability can be maintained. That is, the disproportionation reaction rate of hypobromous acid ion or hypobromous acid ion is obtained by preliminarily containing chloride ion or bromide ion, which is a decomposition product of the disproportionation reaction, in the treatment liquid of the present invention. Is considered to be able to be reduced.
• hypobromous acid ion or hypobromous acid ion which is a chemical species that etches ruthenium
• the change in the concentration of hypobromous acid ion or hypobromous acid ion becomes small, and not only the ruthenium etching rate is stabilized, but also the storage stability of the treatment liquid is improved.
• the life of the treatment liquid can be extended.
• the processing liquid for the semiconductor wafer of the present invention not only the wafer processing efficiency per unit time is improved, but also, for example, a semiconductor manufacturing process in which precise etching control is required for the wiring material. It can be suitably used as a treatment liquid for the metal etching back process in the above. Further, since it has the same effect on metals other than ruthenium, it can be used as a treatment liquid not only for ruthenium but also for metals contained in semiconductor wafers.
• hypohalogenate ion contained in the treatment liquid of the present invention acts as an oxidizing agent for metals such as ruthenium, and forms an oxide of the metal or changes the metal into an ionic species to form a metal layer. Etch.
• hypochlorite ion contained in the treatment liquid of the present invention examples include hypochlorite ion (ClO ⁇ ), hypobromous acid ion (BrO ⁇ ), and hypoiodous acid ion (IO ⁇ ).
• the hypochlorite ion may include at least one selected from hypochlorite ion and hypobromous acid ion in terms of etching rate with respect to metal, stability during storage or use, and the like. preferable.
• hypobromous acid ion is particularly preferable from the viewpoint of the etching rate for ruthenium and the ability to suppress the generation of toxic ruthenium gas (RuO 4 ) that is likely to be generated by the oxidation of ruthenium.
• the hypohalogenate ion only one kind may be used, or two or more kinds of hypohalogenate ions may be included and used.
• the treatment liquid of the present invention may contain two types of hypochlorite ions, hypochlorite ion and hypobromous acid ion.
• the hypohalogenate ion used in the present invention can be generated by dissolving hypohalogenate or hypohalite in a treatment solution.
• the hypohalite include alkali metal salts, alkaline earth metal salts, organic salts and the like.
• Specific examples of the alkali metal salt include sodium hypochlorite, sodium hypobromite, sodium hypoiodous acid and the like
• examples of the organic salt include tetramethylammonium hypochlorite and hypoiodous acid.
• examples thereof include organic salts containing onium ions such as tetramethylammonium or a quaternary alkylammonium salt such as tetramethylammonium hypoiodous acid.
• an organic salt containing onium ions such as a quaternary alkylammonium salt, which does not contain a metal that causes a decrease in yield in the semiconductor forming step, and in particular, tetramethylammonium hypochlorite or the following. It is preferable to use tetramethylammonium bromineate.
• the hypohalite may be an industrially available salt or may be prepared by a known method.
• the quaternary alkylammonium salt can be prepared by preparing an aqueous solution of tetramethylammonium hydroxide and injecting chlorine, bromine or the like. Further, the tetramethylammonium hydroxide solution is brought into contact with the cation exchange type ion exchange resin to convert the cations in the ion exchange resin into tetramethylammonium ions, and then the sodium hypophosphite solution is circulated to flow the sodium ion and tetramethyl.
• a solution containing a quaternary alkylammonium salt of hypohalogenate can also be prepared by exchanging ammonium ions.
• the concentration of hypohalogenate ion in the treatment liquid of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, and may be appropriately set according to the type of metal species to be etched and the etching site. Just do it.
• the concentration is preferably in the range of 0.0010 mol / L or more and 4.00 mol / L or less with respect to the treatment liquid from the viewpoint of etching rate with respect to metal, stability during storage or use, and the like.
• hypohalogenate ions it is more preferably in the range of 0.0050 mol / L or more and 2.00 mol / L or less, and particularly preferably in the range of 0.010 mol / L or more and 0.80 mol / L or less.
• concentration is also referred to as "content”.
• the concentration range of the hypochlorite ion is more preferably 0.020 mol / L or more and 3.00 mol / L or less, and further preferably. Is 0.060 mol / L or more and 2.00 mol / L or less, more preferably 0.10 mol / L or more and 1.20 mol / L or less, and particularly preferably 0.10 mol / L or more and 0.80 mol / L. It is L or less.
• the concentration range of the hypobromous acid ion is more preferably 0.0010 mol / L or more and 0.20 mol / L or less. If it is less than 0.0010 mol / L, the rate of etching the metal tends to be low. On the other hand, when it exceeds 0.20 mol / L, the decomposition of hypobromous acid ion is likely to occur, so that the etching rate for the metal becomes difficult to stabilize.
• the concentration of the hypobromous acid ion is more preferably 0.0010 mol / L or more and 0.20 mol / L or less, more preferably 0.0050 mol. It is more preferably / L or more and 0.20 mol / L or less, and most preferably 0.010 mol / L or more and 0.10 mol / L or less.
• hypobromous acid ion When hypobromous acid ion is used as the hypochlorite ion, it is preferable to further include hypochlorite ion.
• hypobromite ion When hypobromite ion is used, bromide ion is generated by reaction with a metal such as ruthenium.
• hypochlorite ion-chloride ion Since the redox potential (0.89 V (at 25 ° C., pH 14, vs. standard hydrogen electrode)) is higher than the redox potential of hypobromide ion-bromide ion (0.76 V (same as above)), the generated bromide ion Oxides to produce hypobromide ions.
• hypobromous acid ion when hypobromous acid ion is used, it is possible to maintain the hypobromous acid ion at a predetermined concentration by further including hypobromous acid ion, and the etching rate can be stably controlled. Is preferable because it facilitates.
• hypobromous acid ion When hypobromous acid ion is further included in the above hypobromous acid ion, the ratio of the content of hypobromous acid ion and hypobromous acid ion and the hypobromous acid ion from the viewpoint of stable control of the etching rate.
• the (mol) / hypobromous acid ion (mol) is preferably in the range of 0.001 or more and 100 or less, more preferably 0.1 or more and 50 or less, and 0.5 or more and 10 The following range is particularly preferable.
• the concentration of hypohalogenate ion in the above-mentioned treatment liquid can be obtained by calculation at the time of manufacturing the treatment liquid, or can be confirmed by using a known method. Specifically, as a measurement method, absorption caused by hypohydranoic acid ion is confirmed by the ultraviolet-visible absorptiometry method, and the absorption peak is prepared using a hypohalite ion solution whose absorption peak intensity and concentration are known. The hypohalogenate ion concentration can be obtained from the calibration line obtained.
• the treatment liquid of the present invention contains at least one anion species selected from halogenate ions, subhalogenates, and halide ions. It is presumed that the surface roughness is suppressed by the interaction of these anion species with the metal.
• the anion species include halogenate ions such as ClO 3- , BrO 3- , or IO 3- ; subhalogen ions such as ClO 2- , BrO 2- , or IO 2- ; Cl- , Br.
• Halogen ions such as - or I- or the like can be mentioned.
• One of these anion species may be contained in the treatment liquid, or two or more kinds of anion species may be contained.
• anion species when two or more kinds of anion species are contained, for example, when ions having the same oxidation number of halogen atoms are contained such that two kinds among halogenate ions are contained, or when one kind of subhalochloride ion and a halide are contained. It is possible to include ions having different oxidation numbers of halogen atoms so that one type of ion is included.
• anion species as used herein represents at least one anion species selected from halogenate ions, subhalogenate ions, and halide ions, unless otherwise specified.
• halide ions are used as the above-mentioned anion species, particularly as the anion species contained in the range of the anion species concentration described later, from the viewpoints of solubility in the treatment liquid, availability, storage stability, cost and the like. Is preferably contained.
• tetramethylammonium chloride which generates chloride ion, which is one of the halide ions by dissolving, has extremely high solubility (up to 70 wt% under the condition of 25 ° C.) and has a small temperature dependence of solubility.
• Precipitates that can cause a decrease in etching rate and an increase in surface roughness are unlikely to occur.
• the treatment liquid contains two or more kinds of anion species.
• the halide ion and the anion species having different oxidation numbers of halogen atoms from the halide ion are used from the viewpoint of effectively suppressing the roughness of the metal surface. It is particularly preferred that it be included.
• the anion species used in the present invention can be generated by dissolving an acid, a salt, or the like containing the anion species in a treatment liquid.
• Acids containing anionic species include halogen acids such as chloric acid, bromic acid, or iodic acid; chloronic acids such as chloric acid, bromine acid, or iodic acid; hydrogen chloride, hydrogen bromide, or iodide. Examples thereof include hydrogen halide such as hydrogen.
• the salt containing anionic species include alkali metal salts, alkaline earth metal salts, organic salts and the like.
• examples of the alkali metal salt include potassium chloride, sodium chlorite, potassium bromide, sodium bromine, potassium iodide, sodium iodate and the like
• examples of the organic salt include tetramethyl chloride.
• examples thereof include organic salts containing onium ions such as quaternary alkylammonium salts such as ammonium, tetramethylammonium bromide, or tetramethylammonium iodide.
• the hydrogen halide can also be generated by dissolving a halogen gas such as chlorine gas, bromine gas, or iodine gas in water.
• the organic salt contains onium ions such as a quaternary alkylammonium salt.
• the organic salts those that can be particularly preferably used in terms of stability, purity, and cost are chloride or bromide or tetramethylammonium iodide, or chloride or bromide or tetraethylammonium iodide, or. Chloride or bromide or tetrapropylammonium iodide and the like can be mentioned.
• the acid or salt containing the anion species used to generate the anion species in the treatment liquid an industrially available salt may be used or may be prepared by a known method.
• the quaternary alkylammonium salt containing the anion species can be prepared by preparing an aqueous solution of tetramethylammonium hydroxide and injecting chlorine, bromine or the like. Further, a tetramethylammonium hydroxide solution is brought into contact with a cation exchange type ion exchange resin to convert the cations in the ion exchange resin into tetramethylammonium ions, and then a halogen acid such as hydrochloric acid, bromic acid, or iodic acid is circulated.
• a solution containing a quaternary alkylammonium salt of the anion species can also be prepared by the method of exchanging ions.
• the concentration of at least one of the above anion species is 0.30 mol / L or more and 6.00 mol / L or less.
• the anion species needs to be contained in the treatment liquid at 0.30 mol / L or more and 6.00 mol / L or less.
• at least one of the contained anion species is contained in the treatment liquid at 0.30 mol / L or more and 6.00 mol / L or less.
• the concentration of the anion species is more preferably 0.30 mol / L or more and 3.00 mol / L or less, and 0.30 mol / L or more and 1.00 mol or less. Most preferably, it is / L or less. Further, the above range may be applied as the total concentration of anion species in the treatment liquid of the present invention.
• the anion species When two or more of the anion species are contained in the treatment liquid, they are contained at the above-mentioned concentrations of 0.30 mol / L or more, 6.00 mol / L or less, etc. from the viewpoint of achieving both sufficient etching rate and smoothness.
• the anion species is preferably a halide ion.
• the concentration of the anion species other than the anion species within the above concentration range is not particularly limited, and is appropriate depending on the type of the metal species to be etched and the etching site. It may be set, and the concentration of other anion species may be 0.30 mol / L or more and 6.00 mol / L or less.
• the total concentration is preferably 6.00 mol / L or less, more preferably 3.00 mol / L or less, and most preferably 1.00 mol / L or less.
• Ratio of concentration (mol / L) of at least one anion species to the above-mentioned concentration of hypohalogenate ion (mol / L) in the treatment liquid Is not particularly limited, but is usually 2 or more, preferably 4 or more, more preferably 6 or more, and further preferably 8 or more, from the viewpoint of effectively suppressing the roughness of the metal surface. It is preferable, usually 500 or less, preferably 200 or less, more preferably 50 or less, further preferably 10 or less, and usually 2 or more and 500 or less, 4 or more and 200 or less. It is preferably 6 or more and 50 or less, and further preferably 8 or more and 10 or less.
• the concentration of anionic species in the above treatment liquid can be measured by using an ion chromatograph method. By using this method, it is possible to identify and quantify anion species by appropriately setting the column type and conditions.
• the treatment liquid of the present invention further contains onium ions.
• onium ions in addition to the above-mentioned anion species, it becomes possible to further suppress the roughness of the metal surface.
• the present inventors speculate that the interaction between the onium ions and the anion species or the metal surface enables uniform etching of the metal.
• onium ion examples include ammonium ion (NH 4 + ), phosphonium ion (PH 4 + ), sulfonium ion (SH 3 + ), and the like.
• the hydrogen atoms of these onium ions may be independently substituted.
• Aryl groups and the like can be mentioned.
• the aryl group in the aralkyl group and the hydrogen atom in the aryl group may be substituted, and the substituent includes a fluorine atom, a chlorine atom, an alkyl group having 1 or more carbon atoms and 15 or less carbon atoms.
• the substituent includes a fluorine atom, a chlorine atom, an alkyl group having 1 or more carbon atoms and 15 or less carbon atoms. Examples thereof include an alkenyl group having 2 or more carbon atoms and 10 or less carbon atoms, an alkoxy group having 1 or more carbon atoms and 9 or less carbon atoms, and an alkenyloxy group having 2 or more carbon atoms and 9 or less carbon atoms.
• the onium ion from the viewpoint of having a high effect of suppressing the roughness of the metal surface, it is preferable that all the hydrogen atoms of the onium ion are independently substituted with an alkyl group having 1 or more carbon atoms and 25 or less carbon atoms. , It is more preferable that it is substituted with an alkyl group having 2 or more carbon atoms and 10 or less carbon atoms, and most preferably it is substituted with an alkyl group having 3 or more carbon atoms and 6 or less carbon atoms.
• Specific examples of such onium ions include tetrapropylammonium ions and tetrabutylammonium ions.
• onium ions may be bonded via an alkylene group.
• the carbon number of the alkylene group that bonds the two types of onium ions is preferably 2 or more and 10 or less.
• Specific examples of such onium ions include hexamethonium ions and decametonium ions.
• an onium ion may have an alicyclic structure or a heterocyclic structure in which two hydrogen atoms of an onium ion are bonded by an alkyl group or an alkylene group.
• onium ions include piperidinium ion, imidazolium ion, pyrrolidinium ion, oxazolium ion, pyridinium ion and the like.
• these ring structures may have a substituent.
• substituents include chlorine, bromine, fluorine, iodine, an alkyl group having 1 or more carbon atoms and 15 or less carbon atoms, an alkenyl group having 2 or more carbon atoms and 10 or less carbon atoms, an alkoxy group having 1 or more carbon atoms and 9 or less carbon atoms.
• an alkenyloxy group having 2 or more carbon atoms and 9 or less carbon atoms can be mentioned.
• onium ion having the above ring structure 1,1-dimethylpiperidinium ion, 1-butyl-2,3-dimethylimidazolium ion, 1-butyl-1-methylpyrrolidinium ion, 5-azoniaspiro [ 4,4] Nonan ion and the like can be mentioned.
• the two types of onium ions having the above ring structure may be bonded via an alkylene group.
• the carbon number of the alkylene group that bonds the two types of onium ions is preferably 2 or more and 10 or less.
• onium ion 3,3'-methylenebis (1-tert-butyl-3-imidazolium) ion or 3,3'-methylenebis (1- (2,6-diisopropylphenyl) -3) -Imidazolium) Ions and the like can be mentioned.
• the concentration of onium ions when the above-mentioned onium ions are contained in the treatment liquid of the present invention is not particularly limited, and may be appropriately determined in consideration of the metal species and the like to be the target of the treatment liquid. If the concentration of onium ions is too high, the etching rate tends to decrease and uneven etching tends to occur on the metal surface. On the other hand, if the concentration of onium ions is too low, not only the effect of suppressing surface roughness tends to decrease, but also the amount of metal that can be treated decreases, so that the number of times the treatment liquid is reused tends to decrease. It is in.
• the concentration of onium ion is usually 0.000010 mol / L or more and 7.00 mol / L or less, and usually 0.000010 mol / L or more and 6.00 mol / L or less, preferably 0.000010 mol / L. As mentioned above, it is more preferably 3.00 mol / L or less, further preferably 0.0010 mol / L or more and 2.00 mol / L or less, and 0.010 mol / L or more and 1.00 mol / L or less. Is particularly preferred.
• Examples of the method of adding onium ions to the treatment liquid of the present invention include a method of generating onium ions by dissolving an onium salt composed of onium ions and anions in the treatment liquid of the present invention.
• an onium ion is contained as a counter ion of the hypohalogenate ion and / or an anion species
• the concentration of the onium ion may be determined in consideration of the content of these onium ions. That is, when the hypohalogenate ion and / or the onium salt of the anionic species is used for the preparation of the treatment liquid of the present invention, the concentration of the onium salt to be added and the total of the onium ions to be added should be within the above range. It should be.
• the compound containing the onium ion is used so that the concentration of the onium ion to be added is within the above range. It may be added. When adding onium ions, only one type may be added, or two or more types may be added in combination. It may contain two or more types of onium ions.
• solvent In the treatment liquid of the present invention, the residue other than the hypohalogenate ion, the anion species, and other additives described in detail below is a solvent, and after preparing each component, the total amount is 100% by weight. The balance is adjusted with a solvent so as to be.
• Water is most preferably used as the solvent.
• the water contained in the treatment liquid of the present invention is preferably water from which metal ions, organic impurities, particles and the like have been removed by distillation treatment, ion exchange treatment, filter treatment, various adsorption treatments, etc., particularly pure water or ultrapure water. Water is preferred.
• an organic solvent may be used as long as the hypohalogenate ion is stably present.
• the organic solvent for example, acetonitrile, sulfolane and the like are used.
• water and an organic solvent may be used in combination as the solvent.
• the weight ratio of water and the organic solvent may be about 60/40 or more and 99.9 / 0.1 or less.
• the content of the solvent in the treatment liquid is not particularly limited, but is usually 30% by weight or more, preferably 80% by weight or more, preferably 90% by weight, from the viewpoint that the above components can be sufficiently dissolved.
• the above is more preferable, 94% by weight or more is further preferable, and usually 99% by weight or less, 98% by weight or less is preferable, and 97% by weight or less is more preferable.
• the treatment liquid of the present invention is derived from the addition of anionic species and onium ions, and also contains a metal (or a metal ion, hereinafter referred to as a metal including the case of a metal ion) in the production of the treatment liquid.
• a metal or a metal ion, hereinafter referred to as a metal including the case of a metal ion
• the contained metal include lithium, sodium, potassium, aluminum, magnesium, calcium, chromium, manganese, iron, nickel, cobalt, copper, silver, cadmium, barium, zinc, lead, or ions thereof. Can be mentioned. However, since these metals can affect the stability of alkylammonium salts, their abundance is preferably small.
• the metal acts as a catalyst for the decomposition of the alkyl group in alkali and promotes the decomposition reaction.
• the content of the metal in the treatment liquid should be small, but the inclusion of a small amount of metal makes it possible to maintain the flatness of the metal surface after the etching treatment (prevent surface roughness). Therefore, the metal content in the treatment liquid is selected from lithium, sodium, potassium, aluminum, magnesium, calcium, chromium, manganese, iron, nickel, cobalt, copper, silver, cadmium, barium, zinc, or lead.
• any one of the metals is 0.01 pt or more and 1 ppb or less, more preferably 1 pt or more and 1 ppb or less, further preferably 1 pt or more and 500 pt or less, and 10 pt or more. Most preferably, it is 200 ppt or less.
• the metal content in the treatment liquid can be measured using an inductively coupled plasma mass spectrometer (for example, ICP-MS, Agilent 8900, manufactured by Agilent Technologies) as described in Examples described later. When the metal content exceeds 1 ppb, the metal content can be suppressed to 1 ppb or less by filtration, distillation, ion exchange, or the like.
• the treatment liquid of the present invention may contain additives that have been conventionally used in the treatment liquid for semiconductors, as long as the object of the present invention is not impaired.
• an acid e.g., an acid, a metal anticorrosion agent, a fluorine compound, an oxidizing agent, a reducing agent, a chelating agent, a surfactant, a pH adjusting agent, an antifoaming agent and the like can be added.
• the pH of the treatment liquid is 7 or more. It is preferably 14 or less.
• the pH is less than 7, the etching rate tends to be unstable because the decomposition of hypohalogenate ion, which is an oxidizing agent, proceeds. Further, when the pH exceeds 14, it becomes difficult for the metal to dissolve, and it tends to be difficult to obtain a sufficient etching rate.
• the pH of the treatment liquid is more preferably 7 or more and 13 or less, more preferably 8 or more and 12 or more. It is more preferably 8.5 or more, and most preferably 11 or less.
• the pH of the treatment liquid is preferably 7 or more and 14 or less, and 8 or more and 14 or less for the same reason as described above. More preferably, it is 9 or more and less than 13.
• the pH of the treatment liquid is preferably 7 or more and 14 or less, preferably 8 or less, for the same reason as described above. As mentioned above, 14 or less is more preferable, and 9 or more and 13 or less are most preferable.
• Acid or alkali can be added to the treatment liquid to adjust the pH of the treatment liquid.
• the acid may be either an inorganic acid or an organic acid, and examples thereof include hydrofluoric acid, hydrochloric acid, hydrobromic acid, nitric acid, acetic acid, sulfuric acid, peroxodisulfate, and formic acid.
• a widely known acid used in a treatment liquid for semiconductors can be used without any limitation.
• the alkali it is preferable to use an organic alkali because it does not contain metal ions that cause a decrease in yield in semiconductor manufacturing.
• tetraalkylammonium hydroxide which is easily industrially available and can stably coexist with the oxidizing agent contained in the treatment liquid, is preferable.
• examples of such tetraalkylammonium hydroxide include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, choline and the like.
• the organic alkali is more preferably tetramethylammonium hydroxide because the number of hydroxide ions per unit weight is large and a high-purity product is easily available.
• the redox potential (at 25 ° C., pH 14, vs. standard hydrogen electrode) of the treatment liquid is not particularly limited, but is preferably 500 mV or more and 1500 mV or less, more preferably 550 mV.
• the above is 1500 mV or less, more preferably 650 mV or more, and 1500 mV or less.
• the redox potential is less than 500 mV, the oxidizing power tends to be low and the etching rate tends to be low.
• it exceeds 1500 mV although the oxidizing power is high, the hypohalogenate ion tends to be decomposed and the treatment liquid tends to be unstable.
• the redox potential of the treatment liquid is the type and / or concentration of hypohydric acid ion, halogenate ion, hypohalogenate ion, or halide ion contained in the treatment liquid, and the type and / of the above-mentioned other additives. Alternatively, it can be easily controlled by appropriately adjusting the concentration, the pH of the treatment liquid, the temperature of the treatment liquid, and the like.
• the processing liquid for the semiconductor wafer of the present invention having the redox potential in the above range adjusted in this manner can be suitably used as the processing liquid for the metal contained in the semiconductor wafer.
• the method for producing the processing liquid for the semiconductor wafer of the present invention is not particularly limited. Specifically, the hypohalogenate ion and the compound that generates the anion species are added to a solvent such as water so as to have a desired concentration, and further, an additive to be added as necessary is added. , The desired pH may be adjusted to obtain the treatment liquid of the present invention. Alternatively, a plurality of solutions (hereinafter, also referred to as “preparation materials”) in which each component is separately blended are prepared, and these preparation materials are mixed immediately before the processing of the semiconductor wafer to obtain the treatment liquid of the present invention. May be good.
• the components contained in the preparation materials include the preparation materials after the preparation materials are mixed.
• the reaction of the components may generate either the hypohalogenate ion and / or the anion species.
• the pH, composition, and the like of the treatment liquid may change due to changes over time, and the etching performance such as the etching rate may change. Therefore, from the viewpoint of suppressing deterioration of etching performance due to aging, it is preferable to prepare a plurality of preparation materials and mix these preparation materials immediately before processing the semiconductor wafer to obtain the treatment liquid of the present invention. ..
• the number of preparation materials may be prepared for each component, but it is preferable to use two types of preparation materials in consideration of operability at the time of mixing and the like. ..
• a method for producing a semiconductor wafer processing liquid specifically, a step of preparing a first solution (preparation material 1) (a step of preparing a first solution), a second step.
• Production comprising a step of preparing a solution (preparation material 2) (a second solution preparation step) and a step of mixing these preparation materials (preferably immediately before processing a semiconductor wafer) (mixing step).
• the method will be described in detail.
• the present production method may include steps other than the above-mentioned first solution adjusting step, second solution adjusting step, and mixing step.
• the advantage of using the two types of preparation materials, the first solution and the second solution is, for example, improvement of the stability of etching performance when relatively unstable hypohalogenate ions are to be used as the treatment liquid.
• the treatment liquid is one liquid, it takes time from the production of the hypohalogenate ion to the processing of the semiconductor wafer at the semiconductor manufacturing factory, so that the hypohalogenate ion decomposes. Etching performance such as etching speed may change.
• the treatment liquid is prepared as two kinds of preparation materials, the first solution and the second solution, and the preparation material 1 and the preparation material 2 are mixed to generate hypohalogenate ions.
• the semiconductor manufacturing plant manufactures a treatment solution containing hypohydranoic acid ions immediately before processing the semiconductor wafer, so that decomposition of hypohydranoic acid ions can be suppressed and stable. It is possible to exhibit the improved etching performance.
• the treatment liquid of the present invention is used in the etchback step, microfabrication is required, and precise etching rate and surface roughness control are required. Therefore, the above embodiment is preferable.
• the preparation material in the present specification may be treated as the above-mentioned semiconductor wafer processing liquid, and in this case, it may be referred to as a semiconductor wafer processing liquid preparation material.
• the components in the two kinds of solutions constituting each preparation material are as follows.
• the halide ions are contained in the first solution.
• the second solution may contain hypohalogenate ions having higher oxidizing power than the halide ions in the first solution.
• hypohalogenate ions include hypobromous acid ions for bromide ions, and hypobromous acid ions and hypobromous acid ions for iodide ions.
• the solution containing the bromide ion is used as the first solution, and the second solution is used.
• the solution may be a solution containing hypobromous acid ion.
• Hypochlorite ion-chloride ion redox potential (0.89 V (at 25 ° C, pH 14, vs. standard hydrogen electrode)) is hypochlorite ion-chloride ion redox potential (0.76 V (same as above))
• hypochlorite ions can oxidize bromide ions to generate hypochlorite ions, which can generate hypochlorite ions.
• a treatment liquid containing the above can be produced.
• the method for preparing the first solution is not particularly limited. Specifically, at least one anion species selected from a halogenate ion, a subhalogenate ion, and a halide ion can be added to a solvent such as water to prepare a first solution. Other additives and the like can be added to the first solution, if necessary.
• hypohalite ion is generated by mixing the two preparation materials of the first solution and the second solution, when the bromide ion or iodide ion is contained in the first solution.
• the ion can be obtained, for example, by dissolving a salt or the like that generates the ion at the time of dissolution in a solution.
• a salt or the like that generates the ion at the time of dissolution in a solution.
• metal salts such as sodium bromide and sodium iodide
• organic salts such as tetraalkylammonium bromide and tetraalkylammonium iodide
• halogen gas such as bromine gas or iodine gas
• hydrogen bromide or hydrogen iodide examples include hydrogen halide.
• organic salts, halogen gases, and hydrogen halides are preferable because they do not contain metals that cause a decrease in yield in semiconductor production.
• the raw material of the bromide ion or the iodide ion is an organic salt.
• organic salts those that can be particularly preferably used in terms of stability, purity, and cost are bromide or tetramethylammonium iodide, bromide or tetraethylammonium iodide, or bromide.
• an organic salt containing onium ion such as tetrapropylammonium iodide can be mentioned.
• organic salt used in the present invention for example, a salt obtained by producing tetraalkylammonium bromide from tetraalkylammonium ion and bromide ion can be used.
• the method for producing tetraalkylammonium bromide is simply to mix an aqueous solution containing tetraalkylammonium hydroxide and an aqueous solution containing bromide ions, or a bromine-containing gas that generates bromide ions when dissolved in water, such as hydrogen bromide. good.
• tetraalkylammonium hydroxide used for producing tetraalkylammonium bromide examples include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide. Among them, tetramethylammonium hydroxide is more preferable because the number of hydroxide ions per unit weight is large and a high-purity product is easily available.
• Bromide ion sources used to produce tetraalkylammonium bromide include hydrogen bromide, lithium bromide, sodium bromide, potassium bromide, rubidium bromide, cesium bromide, or bromide. Examples include ammonium. Among them, hydrogen bromide is preferable because it contains substantially no metal, is easily available industrially, and a high-purity product is easily available. In the above, bromide is taken up as an organic salt, but iodide can also be used in the same manner as described above.
• the concentration of at least one anion species selected from the halide ion, the subhalotic acid ion, and the halide ion contained in the first solution is mixed with the second solution to obtain the treatment solution of the present invention. If this is the case, the desired concentration may be appropriately set. For example, when the first solution and the second solution are mixed so as not to generate hypohalogenate ions, the anion species contained in the first solution in consideration of the volume of the treated liquid after mixing. You can set the concentration. On the other hand, when the first solution and the second solution are mixed to generate hypohalogenate ions, the concentration of halide ions contained in the first solution is the same as the generation of hypohalogenate ions. It may be set in consideration of the amount of halide ions consumed.
• the concentration of at least one anion species selected from the halogenate ion, the subhalogenate ion, and the halide ion in the first solution is usually 0 from the viewpoint of effectively suppressing the roughness of the metal surface. It is .4 mol / L or more, preferably 0.7 mol / L or more, more preferably 1.5 mol / L or more, and usually 6.0 mol / L or less, 2.5 mol / L. It is preferably less than or equal to, and more preferably 1.5 mol / L or less. Further, the above range may be applied as the total concentration of anion species in the first solution.
• the first solution may contain a component other than the halogenate ion, and may contain, for example, the above-mentioned solvent and other additives.
• the pH of the first solution is not particularly limited, and it is preferable to mix it with the second solution and appropriately set the pH to be, for example, the pH desired for the treatment liquid of the present invention.
• the pH is preferably 7 or more and 14 or less, and more preferably 8 or more and 14 or less.
• a solution in this pH range can reduce the pH drop that occurs when mixed with a second solution, which will be described later, and can stably produce, store, and use the finally obtained treatment solution. It becomes.
• the pH of the first solution is less than 8, adjust the pH and amount of the first solution so that the pH of the treated solution after mixing becomes alkaline when mixed with the second solution. Just do it.
• the other components contained in the first solution it is preferable to use the above-mentioned solvent described in the treatment liquid of the present invention, other additives, and a pH adjuster.
• the method for preparing the second solution is not particularly limited. Specifically, hypohalogenate ions can be added to a solvent such as water, and if necessary, an additive to be added can be added to obtain a second solution of the present invention.
• hypobromous acid ion for example, sodium hypochlorite, sodium hypobromous acid, tetraalkylammonium hypobromous acid, tetraalkylammonium hypobromous acid, or the like can be used.
• tetraalkylammonium hypochlorite or tetraalkylammonium hypobromous acid which does not contain a metal that causes a decrease in yield in the semiconductor forming step.
• the tetraalkylammonium hypohalide may be prepared by a known method.
• an aqueous solution containing tetraalkylammonium hypochlorous acid can be prepared by preparing an aqueous solution of tetraalkylammonium hydroxide and blowing chlorine into it.
• the tetraalkylammonary hydroxide solution is brought into contact with the cation exchange type ion exchange resin, the cation in the ion exchange resin is changed to the tetraalkylammonium ion, and then the sodium hypochlorite solution is circulated to form sodium ions and tetraalkyl.
• a solution containing tetraalkylammonary hypochlorite can also be prepared by exchanging ammonium ions.
• the concentration of the hypohalogenate ion contained in the second solution may be appropriately set so as to be a desired concentration when mixed with the first solution to prepare the treatment liquid of the present invention.
• the hypohalogenate contained in the second solution is taken into consideration in consideration of the volume of the treated liquid after mixing.
• the ion concentration may be set.
• the concentration of hypohalogenate ions contained in the second solution is that of hypohalogenate ions. It may be set in consideration of the amount of hypohalogenate ion consumed for generation.
• the concentration of hypohalogenate ion in the second solution is usually 0.05 mol / L or more, and 0.1 mol / L or more, from the viewpoint of effectively suppressing the roughness of the metal surface. It is more preferably 0.2 mol / L or more, and usually 3.5 mol / L or less, preferably 0.8 mol / L or less, and more preferably 0.3 mol / L or less. It is preferably 0.2 mol / L or less, and more preferably 0.2 mol / L or less.
• the ratio of the amount of the second solution used to the amount of the first solution used is not particularly limited, but effectively suppresses the roughness of the metal surface. From this point of view, the weight ratio is usually 0.1 or more, preferably 0.15 or more, more preferably 0.25 or more, and usually 10 or less, and 6 or less. Is preferable, and 4 or less is more preferable.
• Concentration of at least one anion species in the first solution (mol / L) relative to the concentration of hypohalogenate ions in the second solution (mol / L) (total of anion species in the first solution) is not particularly limited, but is usually 2 or more and 4 or more from the viewpoint of effectively suppressing the roughness of the metal surface. It is preferably 6 or more, more preferably 8 or more, and usually 500 or less, preferably 200 or less, more preferably 50 or less, and 10 or less. The following is more preferable.
• the second solution may contain components other than the anionic species, and may contain, for example, the above-mentioned solvent and other additives.
• the pH of the second solution is not particularly limited, and it is preferable to mix it with the first solution and appropriately set the pH to be, for example, the pH desired for the treatment liquid of the present invention.
• the pH is preferably 7 or more and 14 or less, more preferably 10 or more and 14 or less, and particularly preferably 12 or more and 14 or less.
• the pH drop that occurs when mixed with the first solution can be reduced, and the treatment solution of the present invention can be stably produced, stored, and used.
• the other components contained in the second solution it is preferable to use the above-mentioned solvent described in the treatment liquid of the present invention, other additives, and a pH adjuster.
• the oxidizing power of the anion species contained in the first solution and the oxidizing power of the hypohalogenate ion contained in the second solution are not particularly limited and can be appropriately set, but the roughness of the metal surface is effective. From the viewpoint of suppressing the above, the oxidizing power of the hypohalogenate ion is preferably higher than that of the anion species.
• the temperature is low, the light is shielded, and the amine is not contained.
• the amine is not contained.
• the temperature is low, the light is shielded, and the amine is not contained.
• the amine is not contained.
• the effect of suppressing the decomposition of oxidizing agents and anionic species in the treatment liquid can be expected.
• the treatment liquid and the preparation material in the container filled with the inert gas it is possible to prevent the contamination of carbon dioxide, so that the stability of the treatment liquid can be maintained.
• the inner surface of the container that is, the surface in contact with the treatment liquid, is made of glass or an organic polymer material. This is because if the inner surface of the reaction vessel is made of glass or an organic polymer material, impurities such as metals, metal oxides, and organic substances can be further reduced.
• At least one solution selected from the first solution and the second solution contains onium ions, and in particular, the first solution and the second solution. It is preferably contained in both solutions of 2.
• onium ion the same aspect as the onium ion described in the above-mentioned treatment liquid of the present invention can be applied.
• the concentration of onium ions in at least one solution selected from the first solution and the second solution is not particularly limited, but is usually 0.00002 mol / L or more from the viewpoint of effectively suppressing the roughness of the metal surface.
• the total concentration of onium ions contained in these solutions with respect to the total amount of the first solution and the second solution is not particularly limited, but is usually 0. It is 0.001 mol / L or more, preferably 0.001 mol / L or more, more preferably 0.01 mol / L or more, and usually 6.0 mol / L or less, 3.0 mol / L or less. It is preferably 2.0 mol / L or less, more preferably 1.0 mol / L or less.
• the concentration of each component contained in the two preparation materials of the first solution and the second solution in the method for producing the treatment liquid of the present invention is not particularly limited, and the preparation materials are mixed and then used as the treatment liquid. It may be prepared so as to have the desired formulation in the case.
• hypochlorite ion of 0.001 mol / L or more and 2.0 mol / L or less
• chloride ion is 0.30 mol / L or more and 5.00 mol / L or less
• chlorate ion is 0.30 mol / L or more and 5.00 mol / L or less
• chlorate ion is 0.60 mol / L or more, 6.0 mol / L or less, and chlorate ions.
• the second solution is a solution containing hypochlorite ions of 0.002 mol / L or more and 4.0 mol / L or less
• the semiconductor is used.
• these preparation materials may be mixed to prepare a processing liquid for a semiconductor wafer.
• the hypochlorous acid ion in the treatment solution contains hypochlorite ion and hypobromine acid ion 0.001 mol / L or more and 2.0 mol / L or less, and the chloride ion is 0.
• chloride ion is used as the first solution.
• the second solution is a solution containing hypochlorite ions of 0.002 or more and 4.0 mol / L or less, and these preparation materials are mixed before processing the semiconductor wafer to process the semiconductor wafer. And it is sufficient.
• a widely known method can be used as a mixing method of the semiconductor chemical solution.
• a method using a mixing tank, a method of mixing in the piping of a semiconductor manufacturing apparatus (in-line mixing), a method of mixing by simultaneously applying a plurality of liquids on a wafer, and the like can be preferably used.
• the preparation materials are mixed in advance from the viewpoint of reliably generating hypohalogenate ions, and then the next step is performed. It is preferable to contact the semiconductor wafer after sufficiently generating the hypohalogenate ion.
• the temperature at which the above-mentioned preparation materials are mixed is not particularly limited as long as the treatment liquid after mixing becomes uniform, and may be appropriately set in the range of usually 0 ° C. or higher and 80 ° C. or lower.
• the mixing time is short because the earlier the generation of the hypohalogenate ions is, the better.
• a method of raising the temperature at the time of mixing can be mentioned, but the higher the temperature, the more the decomposition of hypohalophobic acid ions contained in the second solution or the treatment liquid after mixing It tends to progress easily.
• the temperature at the time of mixing the preparation materials is more preferably 10 ° C. or higher and 60 ° C. or lower, more preferably 20 ° C. As mentioned above, it is most preferable that the temperature is 50 ° C. or lower.
• the mixing time of the preparation material when the first solution and the second solution are mixed and hypohalogenate ions are not generated, the temperature and composition concentration of the mixed treatment liquid are uniform. It may be done until it becomes, and usually it may be set appropriately within 30 minutes. On the other hand, when the first solution and the second solution are mixed to generate hypohalogenate ions, it is better that the mixing time is long in order to surely generate hypohalogenate ions. From the viewpoint of throughput, it may be appropriately set within 60 minutes, and the lower limit of the mixing time does not need to be set in particular, but is usually 5 minutes or more.
• a processing liquid for a semiconductor wafer particularly a processing liquid for a semiconductor wafer of the present invention can be manufactured.
• the processing liquid of the semiconductor wafer manufactured by this manufacturing method and the processing liquid of the present invention described above not only the wafer processing efficiency per unit time is improved, but also, for example, precise etching with respect to the wiring material is performed.
• It can be suitably used as a treatment liquid for a metal etchback process in a semiconductor manufacturing process, which requires control of the above.
• it since it has the same effect on metals other than ruthenium, it can be used as an etching solution not only for ruthenium but also for metals contained in semiconductor wafers.
• the treatment liquid for the semiconductor wafer of the present invention a method of using the processing liquid for the semiconductor wafer manufactured by the present manufacturing method or the above-mentioned treatment liquid (hereinafter, these are collectively referred to as “the treatment liquid for the semiconductor wafer of the present invention”) will be described.
• the preparation material according to another embodiment of the present invention is a first solution containing at least one anion species selected from a halogenate ion, a hypohalite ion, and a halide ion, and a hypohalogenate. It is a material for preparing a treatment liquid for a semiconductor wafer, which comprises a second solution containing ions, and the conditions of the first solution and the second solution described above are the conditions of the first solution and the second solution described above. The conditions can be applied as well.
• the contents of the first solution and the second solution contained in the preparation material of the present invention are not particularly limited, but the preparation material may be composed of only the first solution and the second solution.
• the content of the first solution in the preparation material is not particularly limited, but is usually 10% by weight or more, preferably 15% by weight or more, from the viewpoint of effectively suppressing the roughness of the metal surface. It is more preferably 20% by weight or more, and usually 90% by weight or less, preferably 60% by weight or less, more preferably 40% by weight or less, and more preferably 30% by weight or less. More preferred.
• the content of the second solution in the preparation material is not particularly limited, but is usually 10% by weight or more, preferably 40% by weight or more, from the viewpoint of effectively suppressing the roughness of the metal surface. It is more preferably 60% by weight or more, further preferably 70% by weight or more, and usually 90% by weight or less, preferably 85% by weight or less, and preferably 80% by weight or less. More preferred.
• kit A kit (also simply referred to as a "kit"), which is another embodiment of the present invention, is a kit for preparing a treatment solution for a semiconductor wafer, and is composed of a halide ion, a hypohalogenate ion, and a halide ion. It is a kit (kit for producing a processing liquid for a semiconductor wafer) including at least a first solution containing at least one selected anion species and a second solution containing hypochlorous acid ions. As the first solution and the second solution thereof, the above-mentioned first solution and the second solution can be used.
• the aspect of the kit is not particularly limited, and for example, a container containing (or storing or retaining) the above-mentioned first solution and a container containing (or storing or retaining) the above-mentioned second solution.
• the aspect as a container having two or more solution accommodating spaces and accommodating the first solution and the second solution in the two solution accommodating spaces, respectively. May be.
• the first solution and the second solution can be stored, transported, and used in a container. Further, by mixing each solution contained in such a kit, a processing liquid for a semiconductor wafer can be prepared.
• each container When used in the form of a kit comprising a container containing a first solution and a container containing the second solution described above, the aspect of each container is not particularly limited and the volume of each container is stored. It can be appropriately designed according to the amount of the solution, for example, it may be 20000 cm 3 or more and 200,000 cm 3 or less, and it may be 4000 cm 3 or more and 20000 cm 3 or less, and the material of each container may be. It is preferable that the material is a material that does not easily react with the contained solution and has little elution of impurities. Further, the amount of the solution contained in each container can be appropriately designed according to the amount of the treatment liquid to be finally obtained.
• the container for example, PP (polypropylene), PE (polyethylene), PTFE, PFA, etc., or other than these, a metal or glass container whose inner wall is coated with these materials can be used.
• the volume and container of the solution accommodating space in the embodiment as a container having two or more solution accommodating spaces and accommodating the first solution and the second solution in the two solution accommodating spaces, respectively.
• the above-mentioned volume and material can be similarly applied to the material of.
• the kit may be a kit containing only the first solution and the second solution, or may be a kit of three or more liquids further including solutions other than these solutions, but production of a treatment liquid. From the viewpoint of simplification of the process, it is preferable that the kit includes only the solution of the first solution and the solution of the second solution. Further, the method for manufacturing the kit is not particularly limited, and the kit can be manufactured by a known method according to each embodiment.
• the semiconductor wafer processing liquid of the present invention not only improves the wafer processing efficiency per unit time, but also requires, for example, precise etching control of the wiring material, which is a metal in a semiconductor manufacturing process. It can be suitably used as a treatment liquid for the etching back process of. Further, since it has the same effect on metals other than ruthenium, it can be used as an etching solution not only for ruthenium but also for metals contained in semiconductor wafers.
• the metal contained in the semiconductor wafer to which the treatment liquid of the present invention is applied Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, Cu, Zr, La, Mo , Or W and the like, and include at least one metal selected from these.
• These metals can be applied as single metal species or alloys of multiple metal species.
• it can be suitably used for metals such as Ru, Rh, Co, Cu, Mo, and W, which are useful as wiring layers.
• Ru, Co, Mo or W is preferable.
• the metal may be formed by any method, and methods widely known in the semiconductor manufacturing process, such as CVD, ALD, PVD, sputtering, or plating, can be used.
• the metal may be an intermetallic compound, an ionic compound, a complex or the like. Further, the metal may be exposed on the surface of the wafer, or may be covered with another metal, a metal oxide film, an insulating film, a resist, or the like. Even when the metal is covered with another material, when the metal comes into contact with the treatment liquid of the present invention and the metal is dissolved, a sufficient etching rate and surface roughness can be achieved at the same time.
• the treatment liquid of the present invention when used in the metal wiring forming step, it is as follows. First, a substrate made of a semiconductor (for example, Si) is prepared. The prepared substrate is subjected to an oxidation treatment to form a silicon oxide film on the substrate. After that, an interlayer insulating film made of a low dielectric constant (Low-k) film is formed, and via holes are formed at predetermined intervals. After forming the via hole, the metal is embedded in the via hole by thermal CVD, and a metal film is further formed. By treating this metal film with the treatment liquid of the present invention, it becomes possible to perform flattening while maintaining a sufficient etching rate.
• a substrate made of a semiconductor for example, Si
• the method of contacting the treatment liquid of the present invention with the semiconductor wafer on which the metal layer is formed is not particularly limited.
• the processing liquid of the present invention may be flowed on the wafer while rotating the semiconductor wafer, or the semiconductor wafer may be immersed in a container filled with the processing liquid of the present invention and brought into contact with the wafer.
• the temperature at which the metal is etched by the treatment liquid of the present invention is not particularly limited, and may be appropriately determined in consideration of the etching rate of the metal, the stability of the treatment liquid, and the like. The higher the temperature, the worse the stability of the treatment liquid tends to be. Therefore, it is preferable that the treatment temperature is low. On the other hand, the etching rate of the metal tends to increase as the temperature increases. From the viewpoint of achieving both the stability of the treatment liquid and the etching rate, the temperature for etching the metal is preferably 10 ° C. or higher and 90 ° C. or lower, more preferably 15 ° C. or higher and 70 ° C. or lower, and 20 ° C. or higher and 60 ° C. or lower. Is most preferable.
• the processing time when etching a metal with the processing liquid of the present invention is in the range of 0.1 minutes or more and 120 minutes or less, preferably 0.3 minutes or more and 60 minutes or less, and the etching conditions and the semiconductor element used. It may be selected as appropriate.
• the treatment liquid can be removed by cleaning the surface of the semiconductor wafer in contact with the treatment liquid with a rinsing liquid or the like.
• the rinsing liquid after using the treatment liquid of the present invention is not particularly limited, and an organic solvent such as alcohol or deionized water can be used.
• the rinsed semiconductor wafer can be used in the next step, such as laminating other wiring materials, after drying the wafer surface, if necessary.
• Tetramethylammonium hypochlorite, tetramethylammonium chlorate, and a semiconductor wafer for evaluation used in Examples and Comparative Examples were prepared by the following methods.
• concentration of metal and metal ions was measured by an inductively coupled plasma mass spectrometer (ICP-MS, Agent8900, manufactured by Azilent Technologies).
• Example 1 Li 0.01ppt, Na 8ppt, Mg 1ppt, Al 50ppt, K 2ppt, Ca 10ppt, Cr 8ppt, Mn 0.5ppt, Fe 11ppt, Co 3ppt, Ni 2ppt, Cu 0.2ppt, It was Zn 11 ppt, Ag 0.01 ppt, Cd 0.5 ppt, Ba 2 ppt, and Pb 10 ppt.
• the ruthenium film, molybdenum film, and tungsten film used in Examples and Comparative Examples were formed as follows.
• the ruthenium film and the molybdenum film were obtained by forming an oxide film on a silicon wafer using a batch thermal oxidation furnace and forming 1200 ⁇ of ruthenium or 1000 ⁇ of molybdenum on the oxide film by a sputtering method.
• the tungsten film was obtained by forming a thermal oxide film in the same manner and forming 8000 ⁇ of tungsten by the CVD method.
• the sheet resistance was measured by a four-probe resistance measuring device (Lorester GP, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) and converted into a film thickness, which was used as the metal film thickness before etching.
• thermometer protection tube manufactured by Cosmos Bead, bottom-sealed type
• thermometer manufactured by Cosmos Bead, bottom-sealed type
• the solution is provided at the tip of a PFA tube (manufactured by Freon Industries, Ltd., F-8011-02), which is connected to a chlorine gas bomb and a nitrogen gas bomb in one opening so that chlorine gas / nitrogen gas can be switched arbitrarily.
• gas cleaning bottle AsOne, gas cleaning bottle, model number 2450/500
• Carbon dioxide in the gas phase was expelled by flowing nitrogen gas from the PFA tube at 200 ccm (25 ° C.) for 20 minutes.
• a magnet stirrer (C-MAG HS10 manufactured by AsOne) was installed in the lower part of the three-necked flask, and while rotating at 300 rpm, the outer periphery of the three-necked flask was cooled with ice water and chlorine gas (manufactured by Fujiox, specification purity 99. 4%) was supplied at 200 ccm (25 ° C.) for 180 minutes, and a 0.75 mol / L tetramethylammonium hypochlorite solution (0.75 mol / L tetramethylammonium chloride, 0.1 mol / L tetramethylammonium hydroxide) was supplied. Included). At this time, the liquid temperature during the reaction was 11 ° C.
• a strongly acidic ion exchange resin (Amberlite IR-120BNa manufactured by Organo Corporation) was put into a glass column (Biocolumn CF-50TK manufactured by AsOne) having an inner diameter of about 45 mm.
• 1 L of 1N hydrochloric acid (manufactured by Wako Pure Chemical Industries, Ltd., for volumetric analysis) is passed through the ion exchange resin column to replace it with a hydrogen type, and 1 L of ultrapure water is added to wash the ion exchange resin with water. The liquid was passed.
• reagents used in Examples and Comparative Examples are as follows. Tetramethylammonium chloride ((CH 3 ) 4 NCl): manufactured by Tokyo Kasei Kogyo Co., Ltd. Tetramethyl ammonium bromide ((CH 3 ) 4 NBr): manufactured by Tokyo Kasei Kogyo Co., Ltd.
• Sodium hypochlorite pentahydrate (NaClO ⁇ 5H) 2 O): Sodium chloride (NaCl) manufactured by Wako Junyaku Kogyo Co., Ltd .: Sodium bromide (NaBr) manufactured by Fujifilm Wako Junyaku Co., Ltd .: Tetrapropylammonium chloride ((C 3H 7 ) 4 NCl) manufactured by Fujifilm Wako Junyaku Co., Ltd. ): Tokyo Kasei Kogyo Co., Ltd. 1,1-dimethylpiperidinium chloride (C 7H 16 NCl): Tokyo Kasei Kogyo Co., Ltd.
• hexamethonium chloride dihydrate (C 12H 30 N 2 Cl 2.2H 2 O) ): Tokyo Kasei Kogyo Co., Ltd. 15 wt% HCl: Kanto Chemical Co., Ltd. (prepared by diluting 35 wt% HCl with ultrapure water) 1mol / L NaOH: Wako Pure Chemical Industries, Ltd.
• Examples 1-38 Comparative Examples 1-27> (Manufacturing of processing liquid for semiconductor wafers) 0.75 mol / L tetramethylammonium hypochlorite aqueous solution, tetramethylammonium chlorate powder, tetramethylammonium chloride, tetramethylammonium bromide, ultrapure water, and 15 wt% HCl, 1 mol, obtained in the above production example. By mixing / LNaOH, 100 mL of a treatment solution having the composition shown in Tables 1 to 3 was obtained.
• Example 16 and 34 and Comparative Examples 8 and 21 sodium hypochlorite pentahydrate was used instead of the 0.75 mol / L tetramethylammonium hypochlorite aqueous solution, and chloride was used instead of tetramethylammonium chloride. Sodium was used instead of tetramethylammonium bromide.
• the concentration of hypohalogenate ion, the concentration of anionic species, and the pH in the treatment liquid of the obtained semiconductor wafer were measured by the following methods. Using the obtained treatment liquid, the etching performance of the metal shown below and the surface evaluation after etching were carried out. The results are shown in Tables 1 to 3.
• the concentration of anion species in the processing liquid of the semiconductor wafer was measured using an ion chromatography analyzer (DIONEX INTERGRON HPLC, manufactured by Thermo SCIENTIFIC). Using KOH as the eluent, 1.2 mL / min. The liquid was passed at the flow rate of. An anion analysis column for hydroxide-based eluent (AS15, manufactured by Thermo SCIENTIFIC) was used as the column, and the column temperature was 30 ° C. After removing the background noise with a suppressor, the anion species in the treatment liquid were quantified by the electric conductivity detector.
• DIONEX INTERGRON HPLC manufactured by Thermo SCIENTIFIC
• PH measurement method The pH of 10 mL of the treatment liquid prepared in Examples and Comparative Examples was measured using a tabletop pH meter (LAQUA F-73, manufactured by HORIBA, Ltd.). The pH measurement was carried out after the treatment liquid was prepared and stabilized at 25 ° C.
• evaluation of metal etching performance 60 mL of the treatment liquid of the example was prepared in a fluororesin container with a lid (manufactured by AsOne, PFA container 94.0 mL). Each evaluation semiconductor wafer piece having a size of 10 ⁇ 20 mm was immersed in a treatment liquid at 25 ° C. or 50 ° C. for 1 minute, and the value obtained by dividing the amount of film thickness change before and after the treatment by the immersion time was calculated as the etching rate. It was evaluated according to the following criteria. In both cases, evaluations A to C are acceptable levels, and evaluation D is an unacceptable level.
• Examples 39 to 41 Comparative Example 28> Prepare the first and second solutions (preparation materials) having the compositions shown in Table 4, and put each solution in a pure bottle (capacity 20 L, inner wall PE, light shielding, made of Kodama resin), N 2 sealed, 25. Stored separately under the conditions of ° C. The solutions stored in each container were mixed at the mixing ratio (volume ratio) shown in Table 4 to obtain a treatment liquid having the composition shown in Table 5. The etching rate and the smoothness of the metal surface were evaluated in the same manner as in Example 1. The results are shown in Table 5.
• Example 42 The treatment liquid of Example 35 and the treatment liquid of Example 41 (first and second solutions (preparation materials)) were prepared, and the day when the liquids were prepared was set as the first day, and the same as in Example 1. A storage test was carried out for 150 days (storage conditions: nitrogen-sealed, shaded, 25 ° C.). The treatment liquid of Example 41 was stored as a first and second solution and mixed immediately before the evaluation to prepare a treatment liquid. The results are shown in Table 6.
• Examples 43 to 56> A treatment liquid having the composition shown in Table 7 was obtained. The etching rate and the smoothness of the metal surface were evaluated in the same manner as in Example 1. The results are shown in Table 7.
• Example 57 The treatment liquid of Comparative Example 13 and the treatment liquid of Example 21 were prepared, and a storage test for 150 days was carried out in the same manner as in Example 1 with the day when the liquids were prepared as the first day (storage condition: nitrogen). Sealed, shaded, 25 ° C). The results are shown in Table 8.
• Example 58 The treatment liquid of Comparative Example 1 and the treatment liquid of Example 2 were prepared, and a storage test for 150 days was carried out in the same manner as in Example 1 with the day when the liquids were prepared as the first day (storage condition: nitrogen). Sealed, shaded, 25 ° C). The results are shown in Table 9.
• Example 42 the performances of the one-component and two-component type (kit) treatment solutions (Examples 35 and 41) are compared, but the metal is compared with the one-component type.
• the two-component type (kit) in which the treatment liquid was produced immediately before the treatment showed excellent etching rate and surface smoothness over a long period of time.
• Table 7 in Examples 43 to 56, the characteristics of the treatment liquid to which onium ion was added in addition to the anion species were evaluated, but the etching rate was maintained by adding onium ion. The surface smoothness was further improved.
• Tables 8 and 9 it was revealed that the treatment liquid according to the embodiment of the present invention containing more anion species was more stable in terms of etching rate and surface smoothness.

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