WO2014115758A1 - Etching solution - Google Patents

Etching solution Download PDF

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Publication number
WO2014115758A1
WO2014115758A1 PCT/JP2014/051237 JP2014051237W WO2014115758A1 WO 2014115758 A1 WO2014115758 A1 WO 2014115758A1 JP 2014051237 W JP2014051237 W JP 2014051237W WO 2014115758 A1 WO2014115758 A1 WO 2014115758A1
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Prior art keywords
etching solution
acid
solution according
nickel
nickel platinum
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PCT/JP2014/051237
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French (fr)
Japanese (ja)
Inventor
斉藤　康夫
冬樹 佐藤
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昭和電工株式会社
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Publication of WO2014115758A1 publication Critical patent/WO2014115758A1/en

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    • 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
    • C23F1/16—Acidic compositions
    • C23F1/30—Acidic 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
    • C23F1/44—Compositions for etching metallic material from a metallic material substrate of different composition
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
    • H01L21/321—After treatment
    • H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
    • H01L21/32133—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only
    • H01L21/32134—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by liquid etching only
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268

Definitions

  • the present invention relates to an etching solution. More particularly, the present invention relates to an etching solution that can selectively remove nickel platinum alloy-based metals without attacking silicon-based materials and other metals and metal compounds.
  • contact resistance is reduced by siliciding electrodes such as a gate, a source, and a drain for miniaturization, power saving, and speeding up of a MOS transistor.
  • siliciding electrodes such as a gate, a source, and a drain for miniaturization, power saving, and speeding up of a MOS transistor.
  • nickel, cobalt, titanium, or tungsten silicide has been used as a metal used for an electrode.
  • nickel platinum silicide is formed using, for example, an alloy obtained by adding several atomic percent to several tens atomic percent of platinum to nickel to further reduce the contact resistance of the electrode and control heat resistance, overgrowth, and the like. The way is done.
  • nickel silicide not containing platinum when nickel silicide not containing platinum is used, as an example, a nickel thin film is formed on a polysilicon surface, nickel silicide is formed in a self-aligning manner by heat treatment (salicide process), and SPM often used in RCA cleaning.
  • a method of removing excess nickel by treatment with (sulfuric acid / hydrogen peroxide (sulfuric acid / hydrogen peroxide)) or HPM (hydrochloric acid / hydrogen peroxide (hydrochloric acid / hydrogen peroxide)) has been used.
  • the above method is not sufficient for the production of a device using nickel platinum silicide.
  • Platinum is a metal with very strong corrosion resistance, and when it is treated with a chemical solution generally used for removing nickel or the like, or SPM or HPM, a residue mainly composed of platinum remains on the surface of the semiconductor device substrate. Such residues cause problems in the electrical characteristics, reliability, yield, and the like of the semiconductor device.
  • aqua regia having a general composition
  • the surface of the material that comes into contact with the liquid, such as silicide is likely to be rough or change in film thickness, which similarly adversely affects the characteristics of the semiconductor device. Therefore, a method of selectively removing the nickel platinum alloy without damaging silicide or other metals has been studied.
  • Patent Document 1 discloses a chemical containing a substance having a property of coordinating with nickel, such as an aqueous solution containing ammonia water or cyanide, in order to first remove most of nickel by SPM and then protect nickel platinum silicide. After the treatment, a method of dissolving and removing platinum with aqua regia having a general composition is disclosed. However, this method is difficult to handle because it uses aqua regia having a strong corrosive force, harmful cyanide and the like.
  • Patent Document 2 discloses a method in which a nickel platinum alloy (hereinafter also referred to as NiPt) is removed with a composition containing methanesulfonic acid, halogen ions, nitric acid, and water, and Al is not damaged.
  • NiPt nickel platinum alloy
  • methanesulfonic acid needs to be purified by distillation or the like for semiconductors, it has a drawback that the cost of the chemical solution is high because of its highly corrosive substance, resulting in high cost of the chemical solution.
  • Patent Document 3 discloses that Ni, Pd or a laminated film thereof functioning as a barrier metal film of a solder bump is removed with an etching solution containing acetic acid, hydrochloric acid, nitric acid and water.
  • an etching solution containing acetic acid, hydrochloric acid, nitric acid and water.
  • aqua regia or a mixed solution of hydrochloric acid, nitric acid and acetic acid is used when Pd is etched. When such an etching solution is used, etching is performed. It is described that there is a problem that the metal for bump electrodes corrodes and lacks, and some of them are dissolved during etching.
  • etching solution diluted 20 to 25 times with acetic acid.
  • corrosion of solder bumps occurs when the reverse aqua regia is diluted 11 times or 51 times.
  • Patent Document 3 does not describe that NiPt can be etched with the above etching solution, or damage to Al, nickel silicide, nickel platinum silicide (hereinafter also referred to as NiPtSi), W, Ti, and the like.
  • JP 2009-176818 A US Patent Application Publication No. 2012/0231632 JP-A-9-213700
  • An object of the present invention is to provide silicon-based materials (Si, SiO 2 , Si 3 N 4 , nickel silicide, NiPtSi, etc.) and nickel platinum alloy-based metals without damaging Al, W, Ti, TiN and TaN. It is an object of the present invention to provide an etching solution that can selectively remove the.
  • an etching solution containing carboxylic acid, an oxidizing halogen compound, and water can contain Si, SiO 2, Si 3 N 4 .
  • nickel platinum alloys can be selectively removed without damaging silicon-based materials such as nickel silicide and nickel platinum silicide, and Al, W, Ti, TiN and TaN, and have completed the present invention. That is, the present invention includes the following matters.
  • An etchant that is 4-55 mmol / kg.
  • the etching solution according to [1] which is for removing nickel platinum alloy-based metals.
  • the halogen compound having oxidizing properties is selected from the group consisting of hypochlorous acid, chloric acid, hypobromous acid, bromic acid, iodic acid, hypoiodous acid, chlorine, bromine, iodine and nitrosyl halide.
  • the halogen compound having oxidizing properties includes a compound produced by mixing a halogen source and an oxidizing agent, and the halogen source is hydrochloric acid, hydrobromic acid, ammonium chloride, ammonium bromide, bromine, chlorine, and 1,
  • the etching solution according to [6], wherein the oxidizing agent is nitric acid.
  • the etching solution according to any one of [1] to [7] further comprising an anionic surfactant.
  • a first liquid containing a halogen source and a second liquid containing an oxidizing agent, wherein at least one of the first liquid and the second liquid contains a carboxylic acid, and the first liquid An etching solution kit in which at least one of the liquid and the second liquid contains water, and the first liquid and the second liquid are mixed immediately before use, according to any one of [1] to [10]
  • An etchant kit that produces an etchant.
  • a method of selectively removing using the etching solution according to any one of [10] to [10].
  • the etching solution of the present invention can selectively remove nickel platinum alloy without damaging silicon-based materials (Si, SiO 2 , Si 3 N 4 , nickel silicide, NiPtSi, etc.). Therefore, it is extremely effective for manufacturing semiconductor devices such as MOS transistors.
  • Example No. of the present invention An Si substrate with a SiO 2 film was formed as Example No. of the present invention.
  • 4 is a SEM image of the surface of SiO 2 after being treated at 50 ° C. for 3 minutes using an etching solution having a composition of 4.
  • the Si substrate with the Si 3 N 4 film is referred to as Example No. 1 of the present invention.
  • 4 is an SEM image of the surface of Si 3 N 4 after being treated at 50 ° C. for 3 minutes using an etching solution having a composition of 4 .
  • the etching solution of the present invention includes a carboxylic acid, an oxidizing halogen compound, and water, and can selectively remove nickel platinum alloy-based metals with respect to silicon-based materials and Al, W, Ti, TiN, and TaN. It is possible to do.
  • the action mechanism of the etching of the nickel platinum alloy by the etching solution of the present invention is estimated as follows. That is, the nickel in the nickel platinum alloy is dissolved by the acid in the etching solution. Platinum is oxidized by a halogen compound having an oxidizing property, and platinum oxide and halogen are further formed into a complex, whereby the compound is easily dissolved in the etching solution. Carboxylic acid improves the wettability of the etching solution with the nickel platinum alloy, and the halogen compound having an oxidizing property easily attacks the surface of the nickel platinum alloy.
  • the carboxylic acid also has a role of controlling the oxidizing halogen compound so as not to corrode materials such as Al, W, Ti, and NiPtSi.
  • the etching solution of the present invention it is possible to provide a processing means effective for a semiconductor device forming method using a salicide process. Furthermore, by optimizing the composition of the etching solution of the present invention, the surface of the substrate treated with this etching solution can be brought into a state where there are very few nickel and platinum residues.
  • the carboxylic acid used in the etching solution of the present invention is preferably a liquid at room temperature.
  • examples thereof include formic acid, acetic acid, propionic acid, butyric acid, pentanoic acid, hexanoic acid, lactic acid as hydroxy acid, and oxalic acid as dicarboxylic acid, which are saturated monocarboxylic acids having 1 to 6 carbon atoms.
  • a saturated monocarboxylic acid having 1 to 6 carbon atoms is preferable, and acetic acid or propionic acid is more preferable because a high-purity product suitable for a semiconductor manufacturing process is easily available and inexpensive.
  • the carboxylic acid is blended in the etching solution in an amount of 75 to 99% by mass, preferably 80 to 95% by mass, more preferably 85 to 95% by mass.
  • carboxylic acid concentration is lower than 75% by mass, the etching rate of NiPt decreases, and NiPt cannot be efficiently removed.
  • carboxylic acid concentration exceeds 99% by mass and approaches 100% by mass, the concentration of the halogen compound having oxidizing properties decreases, and the etching rate of NiPt decreases.
  • a plurality of the above carboxylic acids may be used in combination. Other saturated carboxylic acids, unsaturated carboxylic acids, aromatic carboxylic acids, dicarboxylic acids, hydroxy acids, carboxylic acid derivatives, etc.
  • these acids or derivatives thereof include succinic acid, malonic acid, malic acid, citric acid, tartaric acid, benzoic acid, phthalic acid, and gallic acid.
  • ascorbic acid may be added.
  • halogen compounds having oxidative properties include halogen alone, hypohalous acid, halogen acid, nitrosyl halide, etc., hypochlorous acid, chloric acid, hypobromite, bromic acid, iodic acid, hypoiodine Acid, chlorine (Cl 2 ), bromine (Br 2 ), iodine and nitrosyl halide are preferred.
  • the halogen alone, the halogen acid, and the hypohalous acid can be included in the etching solution by blowing fluorine or chlorine as a gas into an etching solution containing water, for example. Bromine (liquid) or iodine (solid) may be introduced into the etching solution.
  • a halogen compound having oxidizing properties can be generated in the etching solution.
  • the halogen source fluorine, hydrofluoric acid, chlorine (Cl 2 ), hydrochloric acid, bromine (Br 2 ), hydrobromic acid, iodine, iodic acid, ammonium fluoride, ammonium chloride, ammonium bromide, 1, 3
  • organic compounds that release halogen (in the liquid) such as dichloro-5,5-dimethylhydantoin.
  • the oxidizing agent include nitric acid, hydrogen peroxide, and ammonium persulfate.
  • halogen source and the oxidizing agent may be used alone or in combination.
  • Most halogenated compounds that are oxidizable are unstable and decompose over time, and it is difficult to obtain high-purity products for semiconductors. Therefore, in consideration of safety and quality, a halogen source and an oxidizing agent are practically used. It is preferable to produce by mixing.
  • combinations of halogen sources and oxidizing agents include the group consisting of hydrochloric acid, hydrobromic acid, ammonium chloride, ammonium bromide, bromine, chlorine, and 1,3-dichloro-5,5-dimethylhydantoin as the halogen source.
  • a combination of at least one selected from nitric acid and nitric acid as an oxidizing agent is mentioned, but considering safety, availability of high-purity products suitable for semiconductor manufacturing processes, nitric acid and hydrochloric acid, and nitric acid and chloride A combination of ammonium is preferred.
  • the concentration of the halogen atom of the oxidizing halogen compound in the etching solution is 1.4 to 55 mmol / kg, and is 2, 5, or 10 mmol depending on the type of the oxidizing halogen compound, or the halogen source and the oxidizing agent. / Kg or more, 50, 45 or 40 mmol / kg or less.
  • the etching rate with respect to Al of the etching solution of the present disclosure may be 5 nm / min or less at 50 ° C., preferably 2 nm / min or less, more preferably 1 nm / min or less.
  • the etching rate for Al can be calculated by the following procedure. An Al thin film with a film thickness of 50 nm (L0) is formed on the Si substrate by sputtering. A substrate having an Al thin film is cut into a 2 ⁇ 2 cm square to obtain a sample piece. Using a sheet resistance meter, the sheet resistance value on the Al thin film side of an unused substrate with a known film thickness is measured, and the sheet resistance value (x) with respect to the film thickness of 50 nm (L0) is measured.
  • the sample piece is treated at 50 ° C. for 3 minutes, and the first sheet resistance value (y) on the Al thin film side is measured.
  • the sample piece is again treated with the same etching solution at 50 ° C. for 3 minutes, and then the second sheet resistance value (z) on the Al thin film side is measured.
  • the sample piece is rinsed with secondary distilled water and air-dried, and then the sheet resistance value is measured.
  • Each sheet resistance value measurement is an average of 6 times, and the film thickness and the etching rate are calculated using the following equations.
  • Film thickness after first treatment (L1) L0 ⁇ (x / y)
  • Film thickness after the second treatment (L2) L0 ⁇ (x / z)
  • Etching rate (L1-L2) / 3 [nm / min]
  • the most common method for producing oxidative halogen compounds is described below.
  • nitric acid is most preferable from the viewpoint of stability.
  • the most common halogen source is hydrochloric acid.
  • the concentration in the case of hydrochloric acid is 0.005 to 0.2% by mass. If it is lower than 0.005% by mass, the concentration of active species that dissolve NiPt is low, and the etching rate of NiPt is low. On the other hand, if it exceeds 0.2% by mass, the damage to Al increases.
  • 0.005 mass% and 0.2 mass% are converted into the chlorine atom concentration of the etching solution, they are 1.4 mmol / kg and 55 mmol / kg, respectively.
  • surfactant In the etching solution of the present invention, if necessary, surfactant, acetonitrile, acetone, methanol, etc. for improving NiPt removability, protecting other materials of devices such as Al, NiPtSi, and improving liquid permeability to patterns.
  • An organic solvent miscible with water such as ethanol, isopropanol, and N-methylpyrrolidone can also be added.
  • Surfactants include cationic, nonionic, or anionic surfactants. Among these, anionic surfactants are used for the purpose of removing metals and other residues and protecting Al, silicon-based materials and the like.
  • anionic surfactant examples include sulfuric acid ester, sulfonic acid, carboxylic acid, phosphoric acid ester, and derivatives and salts thereof having a linear alkyl group having 8 to 20 carbon atoms.
  • anionic surfactant has a linear alkyl group having 12 carbon atoms
  • anionic surfactant ammonium dodecyl sulfate, triethanolamine dodecyl sulfate, dodecylbenzenesulfonic acid, dodecylsulfonic acid , Dodecyl diphenyl ether disulfonic acid, and derivatives and salts thereof, but the type of the anionic surfactant is not particularly limited.
  • anionic surfactants may be added in the form of a salt.
  • nonionic surfactants such as a polyoxyalkylene alkyl ether derivative which shows a defoaming effect
  • the etching solution of the present invention needs to be mixed with a carboxylic acid, an oxidizing halogen compound such as hypohalous acid or halogen acid, and water at the time of use.
  • hypohalous acid and halogen acid are easily decomposed in the prepared etching solution, when transporting, the halogen source and the oxidizing agent are divided into two or more liquids, and these liquids are mixed immediately before use.
  • An etchant may be prepared and hypohalous acid or halogen acid may be generated in the etchant.
  • the first liquid containing a halogen source and the second liquid containing an oxidizing agent are included, at least one of the first liquid and the second liquid containing a carboxylic acid, and the first liquid
  • An etchant kit in which at least one of the second liquid and the second liquid contains water can be used.
  • the first liquid may be a mixed liquid of carboxylic acid, water, and nitric acid
  • the second liquid may be a carboxylic acid, water, and a halogen source.
  • the first liquid may be carboxylic acid, water, and nitric acid
  • the second liquid may be a halogen source.
  • nickel platinum alloy-based metal is an alloy containing nickel and platinum as main components, and typically, nickel is 80 to 99.5 atomic%, and platinum is 0.5 to 20 atoms. % Alloy.
  • metals other than platinum for example, noble metals such as gold, palladium, iridium, ruthenium and rhodium, corrosion resistant metals such as tantalum and hafnium, germanium, other general metals, and those Metals that can be treated with the etching solution of the present invention also contain impurity components, such as carbon, which are inevitable to be mixed during metal nitrides and oxides, metal processing, refining, and film formation, such as carbon. Included in the range.
  • the etching solution of the present invention can be used for removing a nickel platinum alloy-based metal formed on a substrate, for example, a nickel platinum alloy-based metal film.
  • the etching solution of the present invention does not attack silicon-based materials such as Si, SiO 2 , Si 3 N 4 , nickel silicide, and Al, W, Ti, TiN, and TaN.
  • the formed nickel platinum alloy metal can be suitably removed.
  • the method for forming a nickel platinum alloy-based metal on the substrate is not particularly limited, and any method such as sputtering, CVD (Chemical Vapor Deposition), ALD (Atomic Layer Deposition), vacuum deposition, plating, etc. is used.
  • film forming conditions and heat treatment conditions are not limited.
  • Si, SiO 2 and Si 3 N 4 are mixed with germanium, boron, nitrogen, phosphorus, arsenic, gallium, antimony, carbon, etc. It may be doped.
  • Nickel silicide in a broad sense includes nickel silicide (nickel silicide), nickel platinum silicide (nickel platinum silicide), etc., and these are formed on the surface of the semiconductor device by heat treatment when manufacturing the semiconductor device. Since the composition and distribution of atoms change, they are also included in those treated with the etching solution of the present invention.
  • the amount of solution used, the number of treatments, the treatment temperature, etc. may be arbitrarily set in order to optimize selectivity and removability according to the formation conditions, film thickness, etc. of the metal thin film. .
  • a liquid temperature preferably 1 to 100 ° C., more preferably 15 to 80 ° C.
  • excellent metal removal property, metal selectivity and liquid life can be obtained.
  • the metal removability may be lowered.
  • it is desirable to heat paying attention to a change in concentration due to decomposition of components and volatilization of components of liquid.
  • NiPt removability was judged by the fact that there was no remaining nickel platinum alloy metal film on the substrate surface and no floating matter was generated in the etching solution.
  • the processing time may be extended and the processing temperature may be increased so as not to damage the silicon-based material.
  • the processing can be usually performed by supplying the etching solution to the surface of the semiconductor wafer with a single wafer cleaning device. Moreover, the process of immersing a semiconductor wafer in etching liquid may be sufficient. These treatments can also be performed using stirring, rocking and / or ultrasonic application. In addition, any device using nickel platinum alloy as a material can be used for electronic devices other than MOS transistors.
  • One embodiment of a method for manufacturing a semiconductor device using the etching solution of the present invention includes the following steps. That is, a step of forming a nickel platinum alloy metal film on at least a part of a substrate made of a silicon material, and etching at least a part of the nickel platinum alloy metal film without damaging the silicon material And selectively removing using a liquid.
  • This method includes, for example, a step of sequentially forming polysilicon and a nickel platinum alloy thin film as electrode materials on at least a part of a substrate made of a silicon-based material, and a step of forming nickel platinum silicide in a self-aligning manner by heat treatment (salicide) And a step of selectively removing unreacted nickel platinum alloy using the etching solution of the present invention.
  • the balance other than the components listed in Tables 1 and 2 is water. Secondary distilled water was used as the water. Acetic acid was used for electronic materials manufactured by Showa Denko KK, and 35 mass% hydrochloric acid and 60 mass% nitric acid were used for electronic materials manufactured by Kishida Chemical Co., Ltd.
  • the water in the etching solution is composed of secondary distilled water and moisture contained in the reagent. The sample piece was put into the etching solution and allowed to stand, and the etching solution was kept at 50 ° C. using a thermostatic bath.
  • the sample piece was treated at 50 ° C. for 3 minutes, and the sheet resistance value (y) on the first thin film side was measured.
  • the sample piece was again treated with the same etching solution at 50 ° C. for 3 minutes, and then the sheet resistance value (z) on the second thin film side was measured.
  • the sample piece was rinsed with secondary distilled water and air-dried, and then the sheet resistance value was measured. Each sheet resistance value measurement was an average of 6 times.
  • the calculation of the specific film thickness and etching rate was performed according to the following formula.
  • Tables 1 and 2 collectively show the etching rates when the Al, W, or Ti film-coated substrates are each immersed in an etching solution.
  • damage evaluation for TaN and TiN was conducted using a sample piece formed by sputtering TaN and TiN with a thickness of 50 nm on a Si substrate. The same procedure was performed using an etching solution having a composition of 4. In both cases, the etching rate was less than 2 nm / min, and good results were obtained.
  • the sheet resistance value was measured after water rinsing and drying. Then, the 2nd etching process was implemented similarly to the 1st etching process, the sheet resistance value was measured after water rinse and drying. The increase rate of the sheet resistance value ⁇ (second sheet resistance value-1st sheet resistance value) / first sheet resistance value ⁇ ⁇ 100 was 1.4%. From this result, it can be seen that the damage of NiPtSi is very small.
  • Damage of SiO 2 and Si 3 N 4 is immersed film coated substrate was formed by sputtering 50nm film thickness of the respective Si substrate of SiO 2 and Si 3 N 4 in 3 minutes etchant 50 ° C., water rinsing Evaluation was made by observing the surface with an electron microscope (SEM) after drying. The results are shown in FIG. 1a (SiO 2 ) and FIG. 1b (Si 3 N 4 ), respectively. No damage was observed on the surfaces of SiO 2 and Si 3 N 4 .
  • the etching solution of the present invention can efficiently remove the nickel platinum alloy without damaging the silicon-based material and the substrate containing Al, W, Ti, TiN, and TaN, it is useful in manufacturing a semiconductor device. .

Abstract

　Provided is an etching solution that can selectively remove nickel platinum alloy metals without damaging silicon materials or Al, W, Ti, TiN and TaN. This etching solution contains carboxylic acid, an oxidizing halogen compound and water. The concentration of the carboxylic acid is 75-99mass%, and the concentration of halogen atoms from the oxidizing halogen compound in the etching solution is 1.4-55mmol/kg.

Description

エッチング液Etching solution
　本発明はエッチング液に関する。さらに詳しくは、本発明は珪素系材料ならびにその他の金属および金属化合物を侵すことなくニッケル白金合金系金属を選択的に除去することができるエッチング液に関する。 The present invention relates to an etching solution. More particularly, the present invention relates to an etching solution that can selectively remove nickel platinum alloy-based metals without attacking silicon-based materials and other metals and metal compounds.
　半導体デバイスに於いて、ＭＯＳ型トランジスタの微細化、省電力化、および高速化のために、ゲート、ソース、ドレインなどの電極をシリサイド化してコンタクト抵抗を低減することが行われている。従来、電極に用いられる金属としては、ニッケル、コバルト、チタンまたはタングステンのシリサイドが用いられてきた。近年、電極のコンタクト抵抗をさらに低下させ、耐熱性、過剰成長などを制御するために、例えば、ニッケルに数原子％～１０数原子％の白金を添加した合金を用いてニッケル白金シリサイドを形成する方法が行われている。 2. Description of the Related Art In semiconductor devices, contact resistance is reduced by siliciding electrodes such as a gate, a source, and a drain for miniaturization, power saving, and speeding up of a MOS transistor. Conventionally, nickel, cobalt, titanium, or tungsten silicide has been used as a metal used for an electrode. In recent years, nickel platinum silicide is formed using, for example, an alloy obtained by adding several atomic percent to several tens atomic percent of platinum to nickel to further reduce the contact resistance of the electrode and control heat resistance, overgrowth, and the like. The way is done.
　これまで、白金を含まないニッケルシリサイドを用いる場合、一例として、ポリシリコン表面にニッケル薄膜を製膜し、熱処理によって自己整合的にニッケルシリサイドを形成し（サリサイドプロセス）、ＲＣＡ洗浄でよく用いられるＳＰＭ（硫酸過水（硫酸／過酸化水素））またはＨＰＭ（塩酸過水（塩酸／過酸化水素））で処理することによって余剰のニッケルを除去する方法が用いられてきた。 Conventionally, when nickel silicide not containing platinum is used, as an example, a nickel thin film is formed on a polysilicon surface, nickel silicide is formed in a self-aligning manner by heat treatment (salicide process), and SPM often used in RCA cleaning. A method of removing excess nickel by treatment with (sulfuric acid / hydrogen peroxide (sulfuric acid / hydrogen peroxide)) or HPM (hydrochloric acid / hydrogen peroxide (hydrochloric acid / hydrogen peroxide)) has been used.
　しかし、ニッケル白金シリサイドを用いるデバイスの作製においては、上記のような方法では不十分である。白金は非常に耐食性の強い金属であり、ニッケル等の除去に一般的に用いられる薬液、またはＳＰＭもしくはＨＰＭで処理すると、半導体デバイス基板表面に主に白金からなる残渣が残留する。このような残渣は、半導体デバイスの電気特性、信頼性、歩留りなどに問題を引き起こす。 However, the above method is not sufficient for the production of a device using nickel platinum silicide. Platinum is a metal with very strong corrosion resistance, and when it is treated with a chemical solution generally used for removing nickel or the like, or SPM or HPM, a residue mainly composed of platinum remains on the surface of the semiconductor device substrate. Such residues cause problems in the electrical characteristics, reliability, yield, and the like of the semiconductor device.
　また、白金の残渣を除去するために強力な溶解能を有するエッチング液、例えば、一般的な組成の王水（例えば３５質量％ＨＣｌ：６０質量％ＨＮＯ３＝３：１（体積比））で処理するとシリサイド等の接液する材質表面に荒れまたは膜厚の変化が生じ易く、同様に半導体デバイスの特性に悪影響を与える。そこで、シリサイドや他の金属にダメージを与えずにニッケル白金合金を選択的に除去する方法が検討されている。 Further, in order to remove platinum residues, an etching solution having a strong dissolving ability, for example, aqua regia having a general composition (for example, 35 mass% HCl: 60 mass% HNO 3 = 3: 1 (volume ratio)) When the treatment is performed, the surface of the material that comes into contact with the liquid, such as silicide, is likely to be rough or change in film thickness, which similarly adversely affects the characteristics of the semiconductor device. Therefore, a method of selectively removing the nickel platinum alloy without damaging silicide or other metals has been studied.
　特許文献１には、まずＳＰＭでニッケルの大部分を除去し、次にニッケル白金シリサイドを保護するため、アンモニア水またはシアン化物を含む水溶液等のニッケルと配位する性質を有する物質を含む薬品で処理した後、一般的な組成の王水で白金を溶解除去する方法が開示されている。しかし、この方法では、強力な腐食力を持つ王水、有害なシアン化物等を用いるため、取り扱いが困難である。 Patent Document 1 discloses a chemical containing a substance having a property of coordinating with nickel, such as an aqueous solution containing ammonia water or cyanide, in order to first remove most of nickel by SPM and then protect nickel platinum silicide. After the treatment, a method of dissolving and removing platinum with aqua regia having a general composition is disclosed. However, this method is difficult to handle because it uses aqua regia having a strong corrosive force, harmful cyanide and the like.
　特許文献２にはメタンスルホン酸、ハロゲンイオン、硝酸および水を含む組成物でニッケル白金合金（以下、ＮｉＰｔともいう）を除去し、かつＡｌにダメージを与えない方法が開示されている。しかしながら、メタンスルホン酸は半導体向けに蒸留等で精製する必要があるが、腐食性が高い物質のため精製コストが高く、その結果、薬液がコスト高になる欠点がある。 Patent Document 2 discloses a method in which a nickel platinum alloy (hereinafter also referred to as NiPt) is removed with a composition containing methanesulfonic acid, halogen ions, nitric acid, and water, and Al is not damaged. However, although methanesulfonic acid needs to be purified by distillation or the like for semiconductors, it has a drawback that the cost of the chemical solution is high because of its highly corrosive substance, resulting in high cost of the chemical solution.
　特許文献３には半田バンプのバリア金属膜として機能するＮｉ、Ｐｄまたはこれらの積層膜を酢酸、塩酸、硝酸および水を含むエッチング液で除去することが開示されている。特許文献３の〔０００９〕には、従来技術としてＰｄをエッチングする場合には王水、または塩酸、硝酸および酢酸の混合溶液が用いられているが、このようなエッチング液を使用した場合、エッチング中にバンプ電極用金属が腐食・欠損し、一部がエッチング中に溶解するという問題があることが記述されている。そこで、特許文献３では塩酸：硝酸＝１：９～１：２０の混合比の逆王水を酢酸で２０～２５倍に希釈したエッチング液で除去することが開示されている。一方で、逆王水を１１倍希釈、５１倍希釈では半田バンプに腐食が発生することが〔００２４〕に記載されている。しかしながら、特許文献３には上記エッチング液によりＮｉＰｔをエッチングできることやＡｌ、ニッケルシリサイド、ニッケル白金シリサイド（以下、ＮｉＰｔＳｉともいう）、Ｗ、Ｔｉ等へのダメージについては記述がない。 Patent Document 3 discloses that Ni, Pd or a laminated film thereof functioning as a barrier metal film of a solder bump is removed with an etching solution containing acetic acid, hydrochloric acid, nitric acid and water. In Patent Document 3 [0009], as a conventional technique, aqua regia or a mixed solution of hydrochloric acid, nitric acid and acetic acid is used when Pd is etched. When such an etching solution is used, etching is performed. It is described that there is a problem that the metal for bump electrodes corrodes and lacks, and some of them are dissolved during etching. Therefore, Patent Document 3 discloses that the reverse aqua regia having a mixture ratio of hydrochloric acid: nitric acid = 1: 9 to 1:20 is removed with an etching solution diluted 20 to 25 times with acetic acid. On the other hand, it is described in [0024] that corrosion of solder bumps occurs when the reverse aqua regia is diluted 11 times or 51 times. However, Patent Document 3 does not describe that NiPt can be etched with the above etching solution, or damage to Al, nickel silicide, nickel platinum silicide (hereinafter also referred to as NiPtSi), W, Ti, and the like.
特開２００９－１７６８１８号公報JP 2009-176818 A 米国特許出願公開第２０１２／０２３１６３２号明細書US Patent Application Publication No. 2012/0231632 特開平９－２１３７００号公報JP-A-9-213700
　本発明の目的は、珪素系材料（Ｓｉ、ＳｉＯ２、Ｓｉ３Ｎ４、ニッケルシリサイド、ＮｉＰｔＳｉ等）、ならびにＡｌ、Ｗ、Ｔｉ、ＴｉＮおよびＴａＮに対してダメージを与えることなくニッケル白金合金系金属を選択的に除去することができるエッチング液を提供することにある。 An object of the present invention is to provide silicon-based materials (Si, SiO 2 , Si 3 N 4 , nickel silicide, NiPtSi, etc.) and nickel platinum alloy-based metals without damaging Al, W, Ti, TiN and TaN. It is an object of the present invention to provide an etching solution that can selectively remove the.
　本発明者らは、ニッケル白金合金を除去する機能を有するエッチング液について鋭意検討した結果、カルボン酸、酸化性を有するハロゲン化合物および水を含むエッチング液により、Ｓｉ、ＳｉＯ２、Ｓｉ３Ｎ４、ニッケルシリサイド、ニッケル白金シリサイド等の珪素系材料、ならびにＡｌ、Ｗ、Ｔｉ、ＴｉＮおよびＴａＮにダメージを与えることなくニッケル白金合金を選択的に除去できることを見出し、本発明を完成するに至った。すなわち、本発明は下記の事項を含む。 As a result of intensive studies on an etching solution having a function of removing a nickel platinum alloy, the present inventors have found that an etching solution containing carboxylic acid, an oxidizing halogen compound, and water can contain Si, SiO 2, Si 3 N 4 , The inventors have found that nickel platinum alloys can be selectively removed without damaging silicon-based materials such as nickel silicide and nickel platinum silicide, and Al, W, Ti, TiN and TaN, and have completed the present invention. That is, the present invention includes the following matters.
［１］カルボン酸、酸化性を有するハロゲン化合物および水を含み、前記カルボン酸濃度が７５質量％以上９９質量％以下、かつ酸化性を有するハロゲン化合物のハロゲン原子のエッチング液中の濃度が１．４～５５ｍｍｏｌ／ｋｇであるエッチング液。
［２］ニッケル白金合金系金属除去用である［１］に記載のエッチング液。
［３］前記カルボン酸が炭素数１～６の飽和モノカルボン酸からなる群から選ばれる少なくとも１種を含む［１］または［２］のいずれかに記載のエッチング液。
［４］前記カルボン酸が酢酸またはプロピオン酸である［１］～［３］のいずれかに記載のエッチング液。
［５］前記酸化性を有するハロゲン化合物が次亜塩素酸、塩素酸、次亜臭素酸、臭素酸、ヨウ素酸、次亜ヨウ素酸、塩素、臭素、ヨウ素およびハロゲン化ニトロシルからなる群から選ばれる少なくとも１種である［１］～［４］のいずれかに記載のエッチング液。
［６］前記酸化性を有するハロゲン化合物がハロゲン源および酸化剤の混合により生成される化合物を含み、ハロゲン源が塩酸、臭化水素酸、塩化アンモニウム、臭化アンモニウム、臭素、塩素、および１，３－ジクロロ－５，５－ジメチルヒダントインからなる群から選ばれる少なくとも１種である［１］～［５］のいずれかに記載のエッチング液。
［７］前記酸化剤が硝酸である［６］に記載のエッチング液。
［８］さらに陰イオン性界面活性剤を含む［１］～［７］のいずれかに記載のエッチング液。
［９］Ａｌ、Ｓｉ、ＳｉＯ２、Ｓｉ３Ｎ４、ニッケルシリサイドおよびニッケル白金シリサイドを侵食しない［１］～［８］のいずれかに記載のエッチング液。
［１０］珪素系材料からなる基板の一部に形成されたニッケル白金合金系金属を除去する［１］～［９］のいずれかに記載のエッチング液。
［１１］ハロゲン源を含む第１の液と、酸化剤を含む第２の液とからなり、前記第１の液および前記第２の液の少なくとも１つがカルボン酸を含み、かつ前記第１の液および前記第２の液の少なくとも１つが水を含むエッチング液キットであって、使用直前に第１の液および第２の液を混合することにより［１］～［１０］のいずれかに記載のエッチング液を生成するエッチング液キット。
［１２］珪素系材料からなる基板の少なくとも一部にニッケル白金合金系金属膜を形成する工程と、前記珪素系材料にダメージを与えることなくニッケル白金合金系金属膜の少なくとも一部を［１］～［１０］のいずれかに記載のエッチング液を用いて選択的に除去する工程とを含むことを特徴とする半導体装置の製造方法。
［１３］前記珪素系材料がＳｉ、ＳｉＯ２、Ｓｉ３Ｎ４、ニッケルシリサイドおよびニッケル白金シリサイドからなる群から選ばれる少なくとも１種である［１２］に記載の半導体装置の製造方法。
［１４］珪素系材料からなる基板の少なくとも一部に電極材料としてポリシリコン、ニッケル白金合金薄膜を順次製膜する工程と、熱処理によって自己整合的にニッケル白金シリサイドを形成する工程（サリサイドプロセス）と、未反応のニッケル白金合金を［１］～［１０］のいずれかに記載のエッチング液を用いて選択的に除去する工程とを含むことを特徴とする半導体装置の製造方法。 [1] It contains a carboxylic acid, an oxidizing halogen compound and water, the carboxylic acid concentration is 75% by mass to 99% by mass, and the halogen atom concentration of the oxidizing halogen compound in the etching solution is 1. An etchant that is 4-55 mmol / kg.
[2] The etching solution according to [1], which is for removing nickel platinum alloy-based metals.
[3] The etching solution according to either [1] or [2], wherein the carboxylic acid contains at least one selected from the group consisting of saturated monocarboxylic acids having 1 to 6 carbon atoms.
[4] The etching solution according to any one of [1] to [3], wherein the carboxylic acid is acetic acid or propionic acid.
[5] The halogen compound having oxidizing properties is selected from the group consisting of hypochlorous acid, chloric acid, hypobromous acid, bromic acid, iodic acid, hypoiodous acid, chlorine, bromine, iodine and nitrosyl halide. The etching solution according to any one of [1] to [4], which is at least one kind.
[6] The halogen compound having oxidizing properties includes a compound produced by mixing a halogen source and an oxidizing agent, and the halogen source is hydrochloric acid, hydrobromic acid, ammonium chloride, ammonium bromide, bromine, chlorine, and 1, The etching solution according to any one of [1] to [5], which is at least one selected from the group consisting of 3-dichloro-5,5-dimethylhydantoin.
[7] The etching solution according to [6], wherein the oxidizing agent is nitric acid.
[8] The etching solution according to any one of [1] to [7], further comprising an anionic surfactant.
[9] The etching solution according to any one of [1] to [8], which does not attack Al, Si, SiO 2 , Si 3 N 4 , nickel silicide, and nickel platinum silicide.
[10] The etching solution according to any one of [1] to [9], which removes a nickel platinum alloy metal formed on a part of a substrate made of a silicon-based material.
[11] A first liquid containing a halogen source and a second liquid containing an oxidizing agent, wherein at least one of the first liquid and the second liquid contains a carboxylic acid, and the first liquid An etching solution kit in which at least one of the liquid and the second liquid contains water, and the first liquid and the second liquid are mixed immediately before use, according to any one of [1] to [10] An etchant kit that produces an etchant.
[12] A step of forming a nickel platinum alloy metal film on at least a part of a substrate made of a silicon material, and at least a part of the nickel platinum alloy metal film without damaging the silicon material [1] A method of selectively removing using the etching solution according to any one of [10] to [10].
[13] The method for manufacturing a semiconductor device according to [12], wherein the silicon-based material is at least one selected from the group consisting of Si, SiO 2 , Si 3 N 4 , nickel silicide, and nickel platinum silicide.
[14] A step of sequentially forming polysilicon and a nickel platinum alloy thin film as electrode materials on at least a part of a substrate made of a silicon-based material, a step of forming nickel platinum silicide in a self-aligning manner by heat treatment (salicide process), And a step of selectively removing unreacted nickel platinum alloy using the etching solution according to any one of [1] to [10].
　本発明のエッチング液は、珪素系材料（Ｓｉ、ＳｉＯ２、Ｓｉ３Ｎ４、ニッケルシリサイド、ＮｉＰｔＳｉ等）に対してダメージを与えずに、ニッケル白金合金を選択的に除去することが可能であるため、ＭＯＳ型トランジスタ等の半導体デバイスの製造に極めて有効である。 The etching solution of the present invention can selectively remove nickel platinum alloy without damaging silicon-based materials (Si, SiO 2 , Si 3 N 4 , nickel silicide, NiPtSi, etc.). Therefore, it is extremely effective for manufacturing semiconductor devices such as MOS transistors.
ＳｉＯ２膜付Ｓｉ基板を本発明の実施例Ｎｏ．４の組成を有するエッチング液を用いて５０℃で３分間処理した後のＳｉＯ２表面のＳＥＭ像である。An Si substrate with a SiO 2 film was formed as Example No. of the present invention. 4 is a SEM image of the surface of SiO 2 after being treated at 50 ° C. for 3 minutes using an etching solution having a composition of 4. Ｓｉ３Ｎ４膜付Ｓｉ基板を本発明の実施例Ｎｏ．４の組成を有するエッチング液を用いて５０℃で３分間処理した後のＳｉ３Ｎ４表面のＳＥＭ像である。The Si substrate with the Si 3 N 4 film is referred to as Example No. 1 of the present invention. 4 is an SEM image of the surface of Si 3 N 4 after being treated at 50 ° C. for 3 minutes using an etching solution having a composition of 4 .
　以下に、本発明の実施形態を詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail.
　本発明のエッチング液は、カルボン酸、酸化性を有するハロゲン化合物および水を含み、珪素系材料ならびにＡｌ、Ｗ、Ｔｉ、ＴｉＮおよびＴａＮに対してニッケル白金合金系金属を選択的に除去することができることを特徴とする。 The etching solution of the present invention includes a carboxylic acid, an oxidizing halogen compound, and water, and can selectively remove nickel platinum alloy-based metals with respect to silicon-based materials and Al, W, Ti, TiN, and TaN. It is possible to do.
　いかなる理論に拘束されるものではないが、本発明のエッチング液によるニッケル白金合金のエッチングの作用メカニズムは以下のように推定される。すなわち、エッチング液中の酸によりニッケル白金合金中のニッケルが溶解する。白金は、酸化性を有するハロゲン化合物により酸化され、白金酸化物とハロゲンがさらに錯体を形成することでエッチング液中に溶解しやすい化合物となる。カルボン酸は、ニッケル白金合金とのエッチング液の濡れ性を向上させ、酸化性を有するハロゲン化合物がニッケル白金合金の表面をアタックしやすくなる。さらにカルボン酸は、酸化性を有するハロゲン化合物が極度にＡｌ、Ｗ、Ｔｉ、ＮｉＰｔＳｉ等の材料を腐食しないように制御する役割も有する。本発明のエッチング液を用いることで、サリサイドプロセスを用いた半導体デバイス形成方法に有効な加工手段を提供することができる。さらに、本発明のエッチング液は、組成を最適化することにより、このエッチング液で処理された基板表面を、ニッケルおよび白金の残留物が非常に少ない状態にすることができる。 Although not bound by any theory, the action mechanism of the etching of the nickel platinum alloy by the etching solution of the present invention is estimated as follows. That is, the nickel in the nickel platinum alloy is dissolved by the acid in the etching solution. Platinum is oxidized by a halogen compound having an oxidizing property, and platinum oxide and halogen are further formed into a complex, whereby the compound is easily dissolved in the etching solution. Carboxylic acid improves the wettability of the etching solution with the nickel platinum alloy, and the halogen compound having an oxidizing property easily attacks the surface of the nickel platinum alloy. Furthermore, the carboxylic acid also has a role of controlling the oxidizing halogen compound so as not to corrode materials such as Al, W, Ti, and NiPtSi. By using the etching solution of the present invention, it is possible to provide a processing means effective for a semiconductor device forming method using a salicide process. Furthermore, by optimizing the composition of the etching solution of the present invention, the surface of the substrate treated with this etching solution can be brought into a state where there are very few nickel and platinum residues.
　本発明のエッチング液に用いられるカルボン酸は常温で液体であるものが好ましい。例えば、炭素数１～６の飽和モノカルボン酸である蟻酸、酢酸、プロピオン酸、酪酸、ペンタン酸、ヘキサン酸、ヒドロキシ酸である乳酸、ジカルボン酸であるシュウ酸等が挙げられる。これらの中でも半導体製造工程に適した高純度の製品が入手しやすく、安価であることから、炭素数１～６の飽和モノカルボン酸が好ましく、酢酸またはプロピオン酸がより好ましい。カルボン酸はエッチング液中に７５質量％以上９９質量％以下配合され、好ましくは８０～９５質量％、より好ましくは８５～９５質量％で配合される。カルボン酸濃度が７５質量％より低いと、ＮｉＰｔのエッチングレートが低下し、効率よくＮｉＰｔを除去することができない。また、カルボン酸濃度が９９質量％を超えて１００質量％に近づくと酸化性を有するハロゲン化合物の濃度が低くなり、ＮｉＰｔのエッチングレートが低下する。上記カルボン酸を複数組み合わせて使用してもよい。エッチング液中に溶解することを条件として、常温で固体である他の飽和カルボン酸、不飽和カルボン酸、芳香族カルボン酸、ジカルボン酸、ヒドロキシ酸、カルボン酸誘導体等を添加してもよい。これらの酸またはその誘導体としては例えば、コハク酸、マロン酸、リンゴ酸、クエン酸、酒石酸、安息香酸、フタル酸、没食子酸等が挙げられる。その他に、アスコルビン酸を添加してもよい。 The carboxylic acid used in the etching solution of the present invention is preferably a liquid at room temperature. Examples thereof include formic acid, acetic acid, propionic acid, butyric acid, pentanoic acid, hexanoic acid, lactic acid as hydroxy acid, and oxalic acid as dicarboxylic acid, which are saturated monocarboxylic acids having 1 to 6 carbon atoms. Among these, a saturated monocarboxylic acid having 1 to 6 carbon atoms is preferable, and acetic acid or propionic acid is more preferable because a high-purity product suitable for a semiconductor manufacturing process is easily available and inexpensive. The carboxylic acid is blended in the etching solution in an amount of 75 to 99% by mass, preferably 80 to 95% by mass, more preferably 85 to 95% by mass. When the carboxylic acid concentration is lower than 75% by mass, the etching rate of NiPt decreases, and NiPt cannot be efficiently removed. On the other hand, when the carboxylic acid concentration exceeds 99% by mass and approaches 100% by mass, the concentration of the halogen compound having oxidizing properties decreases, and the etching rate of NiPt decreases. A plurality of the above carboxylic acids may be used in combination. Other saturated carboxylic acids, unsaturated carboxylic acids, aromatic carboxylic acids, dicarboxylic acids, hydroxy acids, carboxylic acid derivatives, etc. that are solid at room temperature may be added on condition that they are dissolved in the etching solution. Examples of these acids or derivatives thereof include succinic acid, malonic acid, malic acid, citric acid, tartaric acid, benzoic acid, phthalic acid, and gallic acid. In addition, ascorbic acid may be added.
　酸化性を有するハロゲン化合物としては、ハロゲン単体、次亜ハロゲン酸、ハロゲン酸、ハロゲン化ニトロシル等が挙げられ、次亜塩素酸、塩素酸、次亜臭素酸、臭素酸、ヨウ素酸、次亜ヨウ素酸、塩素（Ｃｌ２）、臭素（Ｂｒ２）、ヨウ素およびハロゲン化ニトロシルが好ましい。ハロゲン単体、ハロゲン酸、および次亜ハロゲン酸は、例えば水を含むエッチング液中にフッ素または塩素をガスとして吹き込むことによりエッチング液中に含ませることができる。臭素（液体）またはヨウ素（固体）をエッチング液中に投入してもよい。また、ハロゲン源および酸化剤を混合し、これらを反応させることにより、酸化性を有するハロゲン化合物をエッチング液中に生成させることもできる。この場合、ハロゲン源としてはフッ素、フッ酸、塩素（Ｃｌ２）、塩酸、臭素（Ｂｒ２）、臭化水素酸、ヨウ素、ヨウ素酸、フッ化アンモニウム、塩化アンモニウム、臭化アンモニウム、１，３－ジクロロ－５，５－ジメチルヒダントイン等の（液中に）ハロゲンを放出する有機化合物等が挙げられる。酸化剤としては硝酸、過酸化水素、過硫酸アンモニウム等が挙げられる。ハロゲン源および酸化剤はそれぞれ単独でも複数組み合わせて使用してもよい。酸化性を有するハロゲン化合物の多くは不安定で経時的に分解し、また、半導体用の高純度品が入手しにくいため、安全面、品質面を考慮すると実用的にはハロゲン源および酸化剤を混合して生成させることが好ましい。ハロゲン源と酸化剤との組み合わせの例としては、ハロゲン源として塩酸、臭化水素酸、塩化アンモニウム、臭化アンモニウム、臭素、塩素、および１，３－ジクロロ－５，５－ジメチルヒダントインからなる群から選ばれる少なくとも１種と、酸化剤として硝酸との組み合わせが挙げられるが、安全性、半導体製造工程に適した高純度品の入手のしやすさなどを考慮すると硝酸と塩酸、および硝酸と塩化アンモニウムの組み合わせが好ましい。酸化性を有するハロゲン化合物のハロゲン原子のエッチング液中の濃度は１．４～５５ｍｍｏｌ／ｋｇであり、酸化性を有するハロゲン化合物、またはハロゲン源および酸化剤の種類に応じて、２、５または１０ｍｍｏｌ／ｋｇ以上、５０、４５または４０ｍｍｏｌ／ｋｇ以下とすることができる。 Examples of halogen compounds having oxidative properties include halogen alone, hypohalous acid, halogen acid, nitrosyl halide, etc., hypochlorous acid, chloric acid, hypobromite, bromic acid, iodic acid, hypoiodine Acid, chlorine (Cl 2 ), bromine (Br 2 ), iodine and nitrosyl halide are preferred. The halogen alone, the halogen acid, and the hypohalous acid can be included in the etching solution by blowing fluorine or chlorine as a gas into an etching solution containing water, for example. Bromine (liquid) or iodine (solid) may be introduced into the etching solution. In addition, by mixing a halogen source and an oxidizing agent and reacting them, a halogen compound having oxidizing properties can be generated in the etching solution. In this case, as the halogen source, fluorine, hydrofluoric acid, chlorine (Cl 2 ), hydrochloric acid, bromine (Br 2 ), hydrobromic acid, iodine, iodic acid, ammonium fluoride, ammonium chloride, ammonium bromide, 1, 3 And organic compounds that release halogen (in the liquid) such as dichloro-5,5-dimethylhydantoin. Examples of the oxidizing agent include nitric acid, hydrogen peroxide, and ammonium persulfate. Each of the halogen source and the oxidizing agent may be used alone or in combination. Most halogenated compounds that are oxidizable are unstable and decompose over time, and it is difficult to obtain high-purity products for semiconductors. Therefore, in consideration of safety and quality, a halogen source and an oxidizing agent are practically used. It is preferable to produce by mixing. Examples of combinations of halogen sources and oxidizing agents include the group consisting of hydrochloric acid, hydrobromic acid, ammonium chloride, ammonium bromide, bromine, chlorine, and 1,3-dichloro-5,5-dimethylhydantoin as the halogen source. A combination of at least one selected from nitric acid and nitric acid as an oxidizing agent is mentioned, but considering safety, availability of high-purity products suitable for semiconductor manufacturing processes, nitric acid and hydrochloric acid, and nitric acid and chloride A combination of ammonium is preferred. The concentration of the halogen atom of the oxidizing halogen compound in the etching solution is 1.4 to 55 mmol / kg, and is 2, 5, or 10 mmol depending on the type of the oxidizing halogen compound, or the halogen source and the oxidizing agent. / Kg or more, 50, 45 or 40 mmol / kg or less.
　本開示のエッチング液のＡｌに対するエッチングレートは、５０℃において５ｎｍ／分以下であってよく、好ましくは２ｎｍ／分以下、より好ましくは１ｎｍ／分以下である。Ａｌに対するエッチングレートは、以下の手順によって算出することができる。Ｓｉ基板上に膜厚５０ｎｍ（Ｌ０）のＡｌ薄膜をスパッタリングにより製膜する。Ａｌ薄膜を有する基板を２×２ｃｍ角に切り出してサンプル片を得る。シート抵抗計を用いて膜厚が既知である未使用の基板のＡｌ薄膜側のシート抵抗値を測定し、膜厚５０ｎｍ（Ｌ０）に対するシート抵抗値（ｘ）を測定する。次に、エッチング液を５０℃、１０分で保温した後、サンプル片を５０℃で３分間処理して１回目のＡｌ薄膜側のシート抵抗値（ｙ）を測定する。サンプル片を再度同一のエッチング液にて５０℃で３分間処理した後で２回目のＡｌ薄膜側のシート抵抗値（ｚ）を測定する。各処理後はサンプル片を二次蒸留水でリンスし空気乾燥してからシート抵抗値を測定する。各々のシート抵抗値測定は６回の平均値とし、膜厚およびエッチングレートの算出を以下の式を用いて行う。
　　　　１回目処理後の膜厚（Ｌ１）＝Ｌ０×（ｘ／ｙ）
　　　　２回目処理後の膜厚（Ｌ２）＝Ｌ０×（ｘ／ｚ）
　　　　エッチングレート＝（Ｌ１－Ｌ２）／３　［ｎｍ／分］ The etching rate with respect to Al of the etching solution of the present disclosure may be 5 nm / min or less at 50 ° C., preferably 2 nm / min or less, more preferably 1 nm / min or less. The etching rate for Al can be calculated by the following procedure. An Al thin film with a film thickness of 50 nm (L0) is formed on the Si substrate by sputtering. A substrate having an Al thin film is cut into a 2 × 2 cm square to obtain a sample piece. Using a sheet resistance meter, the sheet resistance value on the Al thin film side of an unused substrate with a known film thickness is measured, and the sheet resistance value (x) with respect to the film thickness of 50 nm (L0) is measured. Next, after keeping the etching solution at 50 ° C. for 10 minutes, the sample piece is treated at 50 ° C. for 3 minutes, and the first sheet resistance value (y) on the Al thin film side is measured. The sample piece is again treated with the same etching solution at 50 ° C. for 3 minutes, and then the second sheet resistance value (z) on the Al thin film side is measured. After each treatment, the sample piece is rinsed with secondary distilled water and air-dried, and then the sheet resistance value is measured. Each sheet resistance value measurement is an average of 6 times, and the film thickness and the etching rate are calculated using the following equations.
Film thickness after first treatment (L1) = L0 × (x / y)
Film thickness after the second treatment (L2) = L0 × (x / z)
Etching rate = (L1-L2) / 3 [nm / min]
　酸化性を有するハロゲン化合物の最も一般的な生成方法を以下に記述する。酸化剤としては安定性の観点から硝酸が最も好ましい。ハロゲン源として、最も一般的なものは塩酸である。塩酸の場合の濃度は０．００５～０．２質量％である。０．００５質量％より低いとＮｉＰｔを溶解する活性種の濃度が薄く、ＮｉＰｔのエッチングレートが小さくなる。一方、０．２質量％を超えるとＡｌへのダメージが大きくなる。０．００５質量％と０．２質量％をエッチング液の塩素原子濃度に換算するとそれぞれ１．４ｍｍｏｌ／ｋｇ、５５ｍｍｏｌ／ｋｇとなる。 The most common method for producing oxidative halogen compounds is described below. As the oxidizing agent, nitric acid is most preferable from the viewpoint of stability. The most common halogen source is hydrochloric acid. The concentration in the case of hydrochloric acid is 0.005 to 0.2% by mass. If it is lower than 0.005% by mass, the concentration of active species that dissolve NiPt is low, and the etching rate of NiPt is low. On the other hand, if it exceeds 0.2% by mass, the damage to Al increases. When 0.005 mass% and 0.2 mass% are converted into the chlorine atom concentration of the etching solution, they are 1.4 mmol / kg and 55 mmol / kg, respectively.
　本発明のエッチング液に、必要に応じて、ＮｉＰｔ除去性向上、Ａｌ、ＮｉＰｔＳｉ等のデバイスの他材料の保護、パターンへの液浸透性向上などのために界面活性剤、アセトニトリル、アセトン、メタノール、エタノール、イソプロパノール、Ｎ－メチルピロリドンに代表される水と混和する有機溶媒等を添加することもできる。界面活性剤としては陽イオン性、非イオン性、または陰イオン性界面活性剤が挙げられる。これらの中で陰イオン性界面活性剤は、金属およびその他の残渣の除去、ならびにＡｌ、珪素系材料などの保護の目的で用いられる。陰イオン性界面活性剤としては、炭素数が８～２０の直鎖アルキル基を有する、硫酸エステル、スルホン酸、カルボン酸、リン酸エステル、ならびにそれらの誘導体および塩が挙げられる。例えば陰イオン性界面活性剤が炭素数１２の直鎖アルキル基を有する場合、陰イオン性界面活性剤として、より具体的にはドデシル硫酸アンモニウム、ドデシル硫酸トリエタノールアミン、ドデシルベンゼンスルホン酸、ドデシルスルホン酸、ドデシルジフェニルエーテルジスルホン酸、ならびにこれらの誘導体および塩等が挙げられるが、陰イオン性界面活性剤であれば、特にその種類が制約されるものではない。これらの陰イオン性界面活性剤は塩の形で添加してもよい。また、消泡作用を示すポリオキシアルキレンアルキルエーテル誘導体等の非イオン性界面活性剤を同時に添加することができる。 In the etching solution of the present invention, if necessary, surfactant, acetonitrile, acetone, methanol, etc. for improving NiPt removability, protecting other materials of devices such as Al, NiPtSi, and improving liquid permeability to patterns. An organic solvent miscible with water such as ethanol, isopropanol, and N-methylpyrrolidone can also be added. Surfactants include cationic, nonionic, or anionic surfactants. Among these, anionic surfactants are used for the purpose of removing metals and other residues and protecting Al, silicon-based materials and the like. Examples of the anionic surfactant include sulfuric acid ester, sulfonic acid, carboxylic acid, phosphoric acid ester, and derivatives and salts thereof having a linear alkyl group having 8 to 20 carbon atoms. For example, when the anionic surfactant has a linear alkyl group having 12 carbon atoms, more specifically, as anionic surfactant, ammonium dodecyl sulfate, triethanolamine dodecyl sulfate, dodecylbenzenesulfonic acid, dodecylsulfonic acid , Dodecyl diphenyl ether disulfonic acid, and derivatives and salts thereof, but the type of the anionic surfactant is not particularly limited. These anionic surfactants may be added in the form of a salt. Moreover, nonionic surfactants, such as a polyoxyalkylene alkyl ether derivative which shows a defoaming effect | action, can be added simultaneously.
　本発明のエッチング液は、使用時にカルボン酸、酸化性を有するハロゲン化合物、例えば次亜ハロゲン酸またはハロゲン酸、および水が混合されていることが必要である。しかしながら、調製したエッチング液中で次亜ハロゲン酸およびハロゲン酸は分解しやすいため、輸送時はハロゲン源と酸化剤を分けて２液以上に分割し、使用直前にこれらの液を混合することによりエッチング液を調製し、エッチング液中に次亜ハロゲン酸またはハロゲン酸を生成させてもよい。そのような実施態様として、ハロゲン源を含む第１の液と、酸化剤を含む第２の液とからなり、第１の液および第２の液の少なくとも１つがカルボン酸を含み、かつ第１の液および第２の液の少なくとも１つが水を含むエッチング液キットを使用することができる。例えば、第１の液をカルボン酸と水と硝酸の混合液に、第２の液をカルボン酸と水とハロゲン源にしてもよい。あるいは第１の液をカルボン酸と水と硝酸、第２の液をハロゲン源にすることも可能である。 The etching solution of the present invention needs to be mixed with a carboxylic acid, an oxidizing halogen compound such as hypohalous acid or halogen acid, and water at the time of use. However, since hypohalous acid and halogen acid are easily decomposed in the prepared etching solution, when transporting, the halogen source and the oxidizing agent are divided into two or more liquids, and these liquids are mixed immediately before use. An etchant may be prepared and hypohalous acid or halogen acid may be generated in the etchant. In such an embodiment, the first liquid containing a halogen source and the second liquid containing an oxidizing agent are included, at least one of the first liquid and the second liquid containing a carboxylic acid, and the first liquid An etchant kit in which at least one of the second liquid and the second liquid contains water can be used. For example, the first liquid may be a mixed liquid of carboxylic acid, water, and nitric acid, and the second liquid may be a carboxylic acid, water, and a halogen source. Alternatively, the first liquid may be carboxylic acid, water, and nitric acid, and the second liquid may be a halogen source.
　本明細書において「ニッケル白金合金系金属」とは、ニッケルおよび白金を主成分として含む合金であり、代表的なものとしてニッケルを８０～９９．５原子％、および白金を０．５～２０原子％含有する合金を指す。さらに、合金の白金含有量の一部として白金以外の金属、例えば、金、パラジウム、イリジウム、ルテニウム、ロジウム等の貴金属、タンタル、ハフニウム等の耐食性金属、ゲルマニウム、その他一般的な金属、さらにそれらの金属の窒化物や酸化物、金属の加工、精錬、製膜等の際に混入を防ぐことが不可避な不純物成分、例えばカーボン等を上記の範囲で含むものも本発明のエッチング液で処理できる金属の範囲に含まれる。 In this specification, “nickel platinum alloy-based metal” is an alloy containing nickel and platinum as main components, and typically, nickel is 80 to 99.5 atomic%, and platinum is 0.5 to 20 atoms. % Alloy. Furthermore, as a part of the platinum content of the alloy, metals other than platinum, for example, noble metals such as gold, palladium, iridium, ruthenium and rhodium, corrosion resistant metals such as tantalum and hafnium, germanium, other general metals, and those Metals that can be treated with the etching solution of the present invention also contain impurity components, such as carbon, which are inevitable to be mixed during metal nitrides and oxides, metal processing, refining, and film formation, such as carbon. Included in the range.
　本発明のエッチング液は、基板に形成されたニッケル白金合金系金属、例えばニッケル白金合金系金属膜の除去に用いることができる。本発明のエッチング液はＳｉ、ＳｉＯ２、Ｓｉ３Ｎ４、ニッケルシリサイド等の珪素系材料ならびにＡｌ、Ｗ、Ｔｉ、ＴｉＮおよびＴａＮを侵食しないので、これらの珪素系材料からなる基板の一部に形成されたニッケル白金合金系金属を好適に除去することができる。ニッケル白金合金系金属の基板上への製膜方法は、特に限定されるものではなく、スパッタリング、ＣＶＤ（Ｃｈｅｍｉｃａｌ　Ｖａｐｏｒ　Ｄｅｐｏｓｉｔｉｏｎ）、ＡＬＤ（Ａｔｏｍｉｃ　Ｌａｙｅｒ　Ｄｅｐｏｓｉｔｉｏｎ）、真空蒸着、めっき等のいずれの手法も用いることができ、また製膜条件や熱処理条件も限定されるものではない。 The etching solution of the present invention can be used for removing a nickel platinum alloy-based metal formed on a substrate, for example, a nickel platinum alloy-based metal film. The etching solution of the present invention does not attack silicon-based materials such as Si, SiO 2 , Si 3 N 4 , nickel silicide, and Al, W, Ti, TiN, and TaN. The formed nickel platinum alloy metal can be suitably removed. The method for forming a nickel platinum alloy-based metal on the substrate is not particularly limited, and any method such as sputtering, CVD (Chemical Vapor Deposition), ALD (Atomic Layer Deposition), vacuum deposition, plating, etc. is used. In addition, film forming conditions and heat treatment conditions are not limited.
　本発明のエッチング液を用いて処理される珪素系材料のうち、Ｓｉ、ＳｉＯ２およびＳｉ３Ｎ４は、ゲルマニウムが混合されたもの、ホウ素、窒素、リン、砒素、ガリウム、アンチモン、カーボン等がドープされたものであってもよい。また、広義のニッケルシリサイドには、ニッケルシリサイド（ニッケルのケイ化物）、ニッケル白金シリサイド（ニッケル白金のケイ化物）等が含まれるが、これらは半導体デバイスを製造する際に熱処理によって半導体デバイス表面上で原子の組成や分布が変化するため、それらも本発明のエッチング液で処理されるものに含まれる。 Among the silicon-based materials processed using the etching solution of the present invention, Si, SiO 2 and Si 3 N 4 are mixed with germanium, boron, nitrogen, phosphorus, arsenic, gallium, antimony, carbon, etc. It may be doped. Nickel silicide in a broad sense includes nickel silicide (nickel silicide), nickel platinum silicide (nickel platinum silicide), etc., and these are formed on the surface of the semiconductor device by heat treatment when manufacturing the semiconductor device. Since the composition and distribution of atoms change, they are also included in those treated with the etching solution of the present invention.
　本発明のエッチング液は、金属薄膜の形成条件、膜厚等に応じて、選択性および除去性を最適化するために、使用する液量、処理回数、処理温度等を任意に設定してよい。液温を望ましくは１～１００℃、さらに望ましくは１５～８０℃として処理を行うことにより、優れた金属除去性、金属選択性および液寿命が得られる。これより低い温度で使用した場合、金属除去性の低下が起こることがある。これより高い温度で使用する場合、成分の分解や液の成分の揮発による濃度変化に留意し、加温することが望ましい。 In the etching solution of the present invention, the amount of solution used, the number of treatments, the treatment temperature, etc. may be arbitrarily set in order to optimize selectivity and removability according to the formation conditions, film thickness, etc. of the metal thin film. . By performing the treatment at a liquid temperature of preferably 1 to 100 ° C., more preferably 15 to 80 ° C., excellent metal removal property, metal selectivity and liquid life can be obtained. When used at a lower temperature, the metal removability may be lowered. When using at a temperature higher than this, it is desirable to heat, paying attention to a change in concentration due to decomposition of components and volatilization of components of liquid.
　本発明のエッチング液を用いて半導体装置を製造する際、珪素系基板材料、Ａｌ、Ｗ、Ｔｉ、ＴｉＮ、ＴａＮ等の部位にダメージを与えない程度に複数回処理し、超純水等による後洗浄を行うことにより、さらに除去性能を向上させることができる。なお、後述する本発明の実施例および比較例では、ＮｉＰｔ除去性は、基板表面のニッケル白金合金系金属膜の残りがなく、かつエッチング液中に浮遊物が発生しないことで判断したが、適用する半導体装置によってさらに厳しい除去性を求められる場合は、珪素系材料にダメージを与えない程度に処理時間の延長や処理温度を高くすればよい。 When manufacturing a semiconductor device using the etching solution of the present invention, it is processed several times so as not to damage parts such as silicon substrate material, Al, W, Ti, TiN, TaN, etc. By performing the cleaning, the removal performance can be further improved. In Examples and Comparative Examples of the present invention to be described later, NiPt removability was judged by the fact that there was no remaining nickel platinum alloy metal film on the substrate surface and no floating matter was generated in the etching solution. When more severe removability is required depending on the semiconductor device to be processed, the processing time may be extended and the processing temperature may be increased so as not to damage the silicon-based material.
　本発明のエッチング液を用いて半導体装置を製造する際、通常は枚葉式洗浄装置で半導体ウェーハ表面にエッチング液を供給することにより処理を行うことができる。また半導体ウェーハをエッチング液に浸漬処理する工程でもよい。また、これらの処理は、攪拌、揺動および／または超音波印加を用いながら行うこともできる。また、ニッケル白金合金を材料として用いるデバイスであれば、ＭＯＳ型トランジスタ以外の電子デバイスにも用いることができる。 When a semiconductor device is manufactured using the etching solution of the present invention, the processing can be usually performed by supplying the etching solution to the surface of the semiconductor wafer with a single wafer cleaning device. Moreover, the process of immersing a semiconductor wafer in etching liquid may be sufficient. These treatments can also be performed using stirring, rocking and / or ultrasonic application. In addition, any device using nickel platinum alloy as a material can be used for electronic devices other than MOS transistors.
　本発明のエッチング液を用いた半導体装置の製造方法の一実施態様は、以下の工程を含む。すなわち、珪素系材料からなる基板の少なくとも一部にニッケル白金合金系金属膜を形成する工程と、前記珪素系材料にダメージを与えることなくニッケル白金合金系金属膜の少なくとも一部を本発明のエッチング液を用いて選択的に除去する工程とを含む。この方法は、例えば、珪素系材料からなる基板の少なくとも一部に電極材料としてポリシリコン、ニッケル白金合金薄膜を順次製膜する工程と、熱処理によって自己整合的にニッケル白金シリサイドを形成する工程（サリサイドプロセス）と、未反応のニッケル白金合金を本発明のエッチング液を用いて選択的に除去する工程とを含む半導体装置の製造に適用できる。 One embodiment of a method for manufacturing a semiconductor device using the etching solution of the present invention includes the following steps. That is, a step of forming a nickel platinum alloy metal film on at least a part of a substrate made of a silicon material, and etching at least a part of the nickel platinum alloy metal film without damaging the silicon material And selectively removing using a liquid. This method includes, for example, a step of sequentially forming polysilicon and a nickel platinum alloy thin film as electrode materials on at least a part of a substrate made of a silicon-based material, and a step of forming nickel platinum silicide in a self-aligning manner by heat treatment (salicide) And a step of selectively removing unreacted nickel platinum alloy using the etching solution of the present invention.
　本発明を以下の実施例および比較例によりさらに詳細に説明するが、本発明はこれらに限定されるものではない。 The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited thereto.
（ニッケル白金合金の除去性評価）
　ニッケル白金合金系金属膜付基板をエッチング液に浸漬した際のニッケルおよび白金の除去性の効果を評価するため、以下の操作を行った。Ｓｉ基板上に９０原子％のニッケルおよび１０原子％の白金の合金からなる薄膜をスパッタリングにより製膜した。膜厚は１５ｎｍとした。この基板を１×１ｃｍ角に切り出して金属除去性評価用のサンプル片を得た。エッチング液の調製は、表１に示した各実施例および表２に示した各比較例の組成となるように各成分を混合することにより調製し、調製したエッチング液をポリエチレン製容器に１０ｍＬ投入した。表１および２に記載されている成分を除く残部は水である。水は二次蒸留水を使用した。酢酸は昭和電工（株）製の電子材料用、３５質量％塩酸および６０質量％硝酸はキシダ化学（株）製の電子材料用を用いた。エッチング液中の水は二次蒸留水および試薬に含まれる水分からなる。エッチング液中に上記サンプル片を投入して静置し、恒温槽を用いてエッチング液を５０℃に保温した。３０分経過後、調製したエッチング液にＮｉＰｔサンプル片を投入し、サンプル片表面を目視で観察し、ＮｉＰｔ起因の金属薄膜が消失した時間をストップウォッチで計測し、エッチングレートを計算した。なお、ＮｉＰｔ膜が基板上に残存した場合やＮｉＰｔ膜が溶解せずに剥離した場合は×とした。表１および２にニッケル白金合金系金属膜付基板をエッチング液に浸漬した際のＮｉＰｔのエッチングレートをまとめて示す。なお、表１における実施例のＮｏ．１１のハロゲン源の種類の欄に記載のＤＣＤＭＨは１，３－ジクロロ－５，５－ジメチルヒダントインを意味し、Ｎｏ．１５のその他欄に記載のＤＰｈＳＡは陰イオン性界面活性剤であるドデシルジフェニルエーテルジスルホン酸アンモニウムを意味する。 (Removability evaluation of nickel platinum alloy)
In order to evaluate the effect of nickel and platinum removability when the substrate with the nickel platinum alloy-based metal film was immersed in an etching solution, the following operation was performed. A thin film made of an alloy of 90 atomic% nickel and 10 atomic% platinum was formed on a Si substrate by sputtering. The film thickness was 15 nm. This substrate was cut into a 1 × 1 cm square to obtain a sample piece for metal removability evaluation. The etching solution was prepared by mixing each component so as to have the composition of each example shown in Table 1 and each comparative example shown in Table 2, and 10 mL of the prepared etching solution was put into a polyethylene container. did. The balance other than the components listed in Tables 1 and 2 is water. Secondary distilled water was used as the water. Acetic acid was used for electronic materials manufactured by Showa Denko KK, and 35 mass% hydrochloric acid and 60 mass% nitric acid were used for electronic materials manufactured by Kishida Chemical Co., Ltd. The water in the etching solution is composed of secondary distilled water and moisture contained in the reagent. The sample piece was put into the etching solution and allowed to stand, and the etching solution was kept at 50 ° C. using a thermostatic bath. After 30 minutes, the NiPt sample piece was put into the prepared etching solution, the surface of the sample piece was visually observed, the time when the metal thin film caused by NiPt disappeared was measured with a stopwatch, and the etching rate was calculated. In addition, when the NiPt film remained on the substrate or when the NiPt film peeled off without being dissolved, it was marked as x. Tables 1 and 2 collectively show the etching rate of NiPt when the nickel platinum alloy-based metal film-coated substrate is immersed in an etching solution. In Table 1, No. of the example. DCDMH described in the column of the type of halogen source of 11 means 1,3-dichloro-5,5-dimethylhydantoin. DPhSA described in the other column of 15 means ammonium dodecyl diphenyl ether disulfonate which is an anionic surfactant.
（Ａｌ、Ｗ、Ｔｉ、ＴｉＮ、ＴａＮのダメージ評価）
　Ａｌ、Ｗ、Ｔｉ膜付基板を各エッチング液に浸漬した際のダメージを評価するため、以下の操作を行った。Ｓｉ基板上にＡｌ（膜厚：５０ｎｍ）、Ｗ（膜厚：１００ｎｍ）またはＴｉ（膜厚：８５ｎｍ）からなる薄膜を各々スパッタリングにより製膜した。これらの基板を２×２ｃｍ角に切り出してサンプル片を得た。エッチングレートの算出は以下の方法により行った。まず、シート抵抗計を用いて膜厚が既知である未使用の基板の薄膜側のシート抵抗値を測定し、特定の膜厚（Ｌ０）に対するシート抵抗値（ｘ）を測定した。次に、エッチング液を５０℃、１０分で保温した後、サンプル片を５０℃で３分間処理して１回目の薄膜側のシート抵抗値（ｙ）を測定した。サンプル片を再度同一のエッチング液にて５０℃で３分間処理した後で２回目の薄膜側のシート抵抗値（ｚ）を測定した。各処理後はサンプル片を二次蒸留水でリンスし空気乾燥してからシート抵抗値を測定した。各々のシート抵抗値測定は６回の平均値とした。具体的な膜厚およびエッチングレートの算出は以下の式の通りに行った。
　　　　１回目処理後の膜厚（Ｌ１）＝Ｌ０×（ｘ／ｙ）
　　　　２回目処理後の膜厚（Ｌ２）＝Ｌ０×（ｘ／ｚ）
　　　　エッチングレート＝（Ｌ１－Ｌ２）／３　［ｎｍ／分］
　なお、今回使用したＡｌの膜厚でシート抵抗にてエッチングレートを評価する方法では、エッチングレートが６．０ｎｍ／分より大きい場合シート抵抗が不安定となり測定ができない。このような場合は、比較例Ｎｏ．１８のように＞６．０ｎｍ／分のように記載した。 (Damage evaluation of Al, W, Ti, TiN, TaN)
In order to evaluate the damage when the Al, W, Ti film-coated substrate was immersed in each etching solution, the following operation was performed. Thin films made of Al (film thickness: 50 nm), W (film thickness: 100 nm) or Ti (film thickness: 85 nm) were formed on the Si substrate by sputtering. These substrates were cut into 2 × 2 cm squares to obtain sample pieces. The etching rate was calculated by the following method. First, the sheet resistance value on the thin film side of an unused substrate having a known film thickness was measured using a sheet resistance meter, and the sheet resistance value (x) with respect to a specific film thickness (L0) was measured. Next, after keeping the etching solution at 50 ° C. for 10 minutes, the sample piece was treated at 50 ° C. for 3 minutes, and the sheet resistance value (y) on the first thin film side was measured. The sample piece was again treated with the same etching solution at 50 ° C. for 3 minutes, and then the sheet resistance value (z) on the second thin film side was measured. After each treatment, the sample piece was rinsed with secondary distilled water and air-dried, and then the sheet resistance value was measured. Each sheet resistance value measurement was an average of 6 times. The calculation of the specific film thickness and etching rate was performed according to the following formula.
Film thickness after first treatment (L1) = L0 × (x / y)
Film thickness after the second treatment (L2) = L0 × (x / z)
Etching rate = (L1-L2) / 3 [nm / min]
In the method of evaluating the etching rate with the sheet resistance using the Al film thickness used this time, the sheet resistance becomes unstable and the measurement cannot be performed when the etching rate is higher than 6.0 nm / min. In such a case, Comparative Example No. It was described as> 6.0 nm / min as in 18.
　Ａｌ、ＷおよびＴｉのレートが５ｎｍ／分以下のものを良好と判断した。表１および２にＡｌ、ＷまたはＴｉ膜付基板を各々エッチング液に浸漬した際のエッチングレートをまとめて示す。 A rate of Al, W and Ti of 5 nm / min or less was judged good. Tables 1 and 2 collectively show the etching rates when the Al, W, or Ti film-coated substrates are each immersed in an etching solution.
　また、Ｓｉ基板上にＴａＮおよびＴｉＮを各々５０ｎｍの膜厚でスパッタリングにより形成したサンプル片を用いてＴａＮおよびＴｉＮに対するダメージ評価をＮｏ．４の組成のエッチング液を用いて同様に行った。ともにエッチングレートは２ｎｍ／分未満であり良好な結果が得られた。 Moreover, damage evaluation for TaN and TiN was conducted using a sample piece formed by sputtering TaN and TiN with a thickness of 50 nm on a Si substrate. The same procedure was performed using an etching solution having a composition of 4. In both cases, the etching rate was less than 2 nm / min, and good results were obtained.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
（ＮｉＰｔＳｉ、ＳｉＯ２、Ｓｉ３Ｎ４のダメージ評価）
　実施例の代表的組成であるＮｏ．４の組成のエッチング液を用いてＮｉＰｔＳｉ、ＳｉＯ２およびＳｉ３Ｎ４のダメージ評価を行った。ＮｉＰｔＳｉ膜はＳｉウェーハ上にＮｉＰｔをスパッタリングし、その後熱処理を行って形成した。その結果、Ｓｉウェーハ上にＮｉＰｔＳｉが８ｎｍ、ＮｉＰｔが１０ｎｍ順次積層されたサンプル片が得られ、このサンプル片をエッチング処理に用いた。ニッケル白金シリサイド（ＮｉＰｔＳｉ）に対して５０℃、３分間で１回目のエッチング処理を実施後、水リンス、乾燥をしてからシート抵抗値を測定した。続いて、１回目のエッチング処理と同様に２回目のエッチング処理を実施し、水リンス、乾燥後にシート抵抗値を測定した。シート抵抗値の増加率｛（２回目のシート抵抗値－１回目のシート抵抗値）／１回目のシート抵抗値｝×１００は１．４％であった。この結果からＮｉＰｔＳｉのダメージが非常に少ないことが分かる。ＳｉＯ２およびＳｉ３Ｎ４のダメージはＳｉＯ２およびＳｉ３Ｎ４を各々Ｓｉ基板上に５０ｎｍの膜厚でスパッタリングにより形成した膜付き基板を５０℃で３分間エッチング液中に浸漬し、水リンス、乾燥後に表面を電子顕微鏡（ＳＥＭ）で観察することにより評価した。結果を図１ａ（ＳｉＯ２）および図１ｂ（Ｓｉ３Ｎ４）にそれぞれ示す。ＳｉＯ２およびＳｉ３Ｎ４の表面にはダメージは観察されなかった。 (Damage evaluation of NiPtSi, SiO 2 , Si 3 N 4 )
No. which is a representative composition of Examples. Damage evaluation of NiPtSi, SiO 2 and Si 3 N 4 was performed using an etching solution having a composition of 4 . The NiPtSi film was formed by sputtering NiPt on a Si wafer and then performing a heat treatment. As a result, a sample piece in which 8 nm of NiPtSi and 10 nm of NiPt were sequentially laminated on the Si wafer was obtained, and this sample piece was used for the etching process. After the first etching treatment was performed on nickel platinum silicide (NiPtSi) at 50 ° C. for 3 minutes, the sheet resistance value was measured after water rinsing and drying. Then, the 2nd etching process was implemented similarly to the 1st etching process, the sheet resistance value was measured after water rinse and drying. The increase rate of the sheet resistance value {(second sheet resistance value-1st sheet resistance value) / first sheet resistance value} × 100 was 1.4%. From this result, it can be seen that the damage of NiPtSi is very small. Damage of SiO 2 and Si 3 N 4 is immersed film coated substrate was formed by sputtering 50nm film thickness of the respective Si substrate of SiO 2 and Si 3 N 4 in 3 minutes etchant 50 ° C., water rinsing Evaluation was made by observing the surface with an electron microscope (SEM) after drying. The results are shown in FIG. 1a (SiO 2 ) and FIG. 1b (Si 3 N 4 ), respectively. No damage was observed on the surfaces of SiO 2 and Si 3 N 4 .
　本発明のエッチング液は、珪素系材料およびＡｌ、Ｗ、Ｔｉ、ＴｉＮおよびＴａＮを含む基板を侵すことなくニッケル白金合金の効率的な除去を行うことができるので、半導体装置の製造上有用である。 Since the etching solution of the present invention can efficiently remove the nickel platinum alloy without damaging the silicon-based material and the substrate containing Al, W, Ti, TiN, and TaN, it is useful in manufacturing a semiconductor device. .

Claims (14)

  1. 　カルボン酸、酸化性を有するハロゲン化合物および水を含み、前記カルボン酸濃度が７５質量％以上９９質量％以下、かつ酸化性を有するハロゲン化合物のハロゲン原子のエッチング液中の濃度が１．４～５５ｍｍｏｌ／ｋｇであるエッチング液。 A carboxylic acid, an oxidizing halogen compound and water, wherein the carboxylic acid concentration is 75% by mass or more and 99% by mass or less, and the halogen atom concentration of the oxidizing halogen compound in the etching solution is 1.4 to 55 mmol. Etching solution that is / kg.
  2. 　ニッケル白金合金系金属除去用である請求項１に記載のエッチング液。 The etching solution according to claim 1, which is used for removing nickel platinum alloy-based metals.
  3. 　前記カルボン酸が炭素数１～６の飽和モノカルボン酸からなる群から選ばれる少なくとも１種を含む請求項１または２のいずれかに記載のエッチング液。 3. The etching solution according to claim 1, wherein the carboxylic acid contains at least one selected from the group consisting of saturated monocarboxylic acids having 1 to 6 carbon atoms.
  4. 　前記カルボン酸が酢酸またはプロピオン酸である請求項１～３のいずれか一項に記載のエッチング液。 The etching solution according to any one of claims 1 to 3, wherein the carboxylic acid is acetic acid or propionic acid.
  5. 　前記酸化性を有するハロゲン化合物が次亜塩素酸、塩素酸、次亜臭素酸、臭素酸、ヨウ素酸、次亜ヨウ素酸、塩素、臭素、ヨウ素およびハロゲン化ニトロシルからなる群から選ばれる少なくとも１種である請求項１～４のいずれか一項に記載のエッチング液。 The halogen compound having oxidizing properties is at least one selected from the group consisting of hypochlorous acid, chloric acid, hypobromous acid, bromic acid, iodic acid, hypoiodic acid, chlorine, bromine, iodine and nitrosyl halide. The etching solution according to any one of claims 1 to 4, wherein
  6. 　前記酸化性を有するハロゲン化合物がハロゲン源および酸化剤の混合により生成される化合物を含み、ハロゲン源が塩酸、臭化水素酸、塩化アンモニウム、臭化アンモニウム、臭素、塩素、および１，３－ジクロロ－５，５－ジメチルヒダントインからなる群から選ばれる少なくとも１種である請求項１～５のいずれか一項に記載のエッチング液。 The halogen compound having oxidizing properties includes a compound produced by mixing a halogen source and an oxidizing agent, and the halogen source is hydrochloric acid, hydrobromic acid, ammonium chloride, ammonium bromide, bromine, chlorine, and 1,3-dichloro The etching solution according to any one of claims 1 to 5, which is at least one selected from the group consisting of -5,5-dimethylhydantoin.
  7. 　前記酸化剤が硝酸である請求項６に記載のエッチング液。 The etching solution according to claim 6, wherein the oxidizing agent is nitric acid.
  8. 　さらに陰イオン性界面活性剤を含む請求項１～７のいずれか一項に記載のエッチング液。 The etching solution according to any one of claims 1 to 7, further comprising an anionic surfactant.
  9. 　Ａｌ、Ｓｉ、ＳｉＯ２、Ｓｉ３Ｎ４、ニッケルシリサイドおよびニッケル白金シリサイドを侵食しない請求項１～８のいずれか一項に記載のエッチング液。 The etching solution according to any one of claims 1 to 8, which does not attack Al, Si, SiO 2 , Si 3 N 4 , nickel silicide and nickel platinum silicide.
  10. 　珪素系材料からなる基板の一部に形成されたニッケル白金合金系金属を除去する請求項１～９のいずれか一項に記載のエッチング液。 The etching solution according to any one of claims 1 to 9, which removes a nickel platinum alloy-based metal formed on a part of a substrate made of a silicon-based material.
  11. 　ハロゲン源を含む第１の液と、酸化剤を含む第２の液とからなり、前記第１の液および前記第２の液の少なくとも１つがカルボン酸を含み、かつ前記第１の液および前記第２の液の少なくとも１つが水を含むエッチング液キットであって、使用直前に第１の液および第２の液を混合することにより請求項１～１０のいずれか一項に記載のエッチング液を生成するエッチング液キット。 A first liquid containing a halogen source and a second liquid containing an oxidizing agent, wherein at least one of the first liquid and the second liquid contains a carboxylic acid, and the first liquid and the 11. The etching solution according to claim 1, wherein at least one of the second solutions is an etching solution kit containing water, and the first solution and the second solution are mixed immediately before use. Etching solution kit to produce.
  12. 　珪素系材料からなる基板の少なくとも一部にニッケル白金合金系金属膜を形成する工程と、前記珪素系材料にダメージを与えることなくニッケル白金合金系金属膜の少なくとも一部を請求項１～１０のいずれか一項に記載のエッチング液を用いて選択的に除去する工程とを含むことを特徴とする半導体装置の製造方法。 The step of forming a nickel platinum alloy metal film on at least a part of a substrate made of a silicon material, and at least a part of the nickel platinum alloy metal film without damaging the silicon material. And a step of selectively removing the semiconductor device using the etching solution according to any one of the above items.
  13. 　前記珪素系材料がＳｉ、ＳｉＯ２、Ｓｉ３Ｎ４、ニッケルシリサイドおよびニッケル白金シリサイドからなる群から選ばれる少なくとも１種である請求項１２に記載の半導体装置の製造方法。 The method of manufacturing a semiconductor device according to claim 12, wherein the silicon-based material is at least one selected from the group consisting of Si, SiO 2 , Si 3 N 4 , nickel silicide, and nickel platinum silicide.
  14. 　珪素系材料からなる基板の少なくとも一部に電極材料としてポリシリコン、ニッケル白金合金薄膜を順次製膜する工程と、熱処理によって自己整合的にニッケル白金シリサイドを形成する工程（サリサイドプロセス）と、未反応のニッケル白金合金を請求項１～１０のいずれか一項に記載のエッチング液を用いて選択的に除去する工程とを含むことを特徴とする半導体装置の製造方法。 A step of sequentially forming polysilicon and a nickel platinum alloy thin film as an electrode material on at least a part of a substrate made of a silicon-based material, a step of forming nickel platinum silicide in a self-aligning manner by heat treatment (salicide process), and unreacted And a step of selectively removing the nickel platinum alloy using the etching solution according to any one of claims 1 to 10.
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