Composition for cleaning semiconductor substrate, method for cleaning semiconductor substrate, and method for producing semiconductor substrate

Abstract

A composition for cleaning a semiconductor substrate, which contains component (A): at least one element selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by formula (a) as a conjugate base, and a salt of an acid having an anion represented by formula (a) as a conjugate base, component (B): a compound represented by formula (b): [MOm (OR) k-2m] x (b) (M is boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus, and titanium, k is the oxidation number of M, k is the number of oxides of M, k is the number of oxides of M, k is the number of oxides of M, and k is the number of oxides of N, and k is the number of oxides of N; m is an integer from 0 to k / 2 (inclusive), x is a positive integer, R is a hydrogen atom, an alkali metal or an alkyl group, and n is a coordination number for fluoride ions of M. ) Component (C): an oxidizing agent and Component (D): water, and [alpha] represented by formula (I) is 0.2-1.1 (inclusive). ([F] is the molar concentration of fluoride ions in the composition, [M] is the molar concentration of M in the composition, and n (M) is the coordination number of fluoride ions with respect to M. > # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a composition for cleaning a semiconductor substrate, a method for cleaning a semiconductor substrate, and a method for manufacturing a semiconductor substrate. Background Art

[0002] When manufacturing semiconductor substrates with high integration of semiconductor elements, a conductive film such as a metal film that becomes conductive wiring, a low dielectric constant interlayer insulating film for insulation between conductive films, a hard mask, etc. are usually formed on a substrate such as a silicon wafer, and then a photoresist is evenly coated on the surface to set a photosensitive layer, and a selective exposure and development process is performed on it to produce a desired photoresist pattern. Then, using the photoresist pattern as a mask, a dry etching process is performed on the substrate stacked with a low dielectric constant interlayer insulating film, a hard mask, etc., thereby forming a desired pattern on the substrate. In addition, a series of processes are usually performed to remove the photoresist pattern and the residue and hard mask generated by the dry etching process using ashing based on oxygen plasma, a cleaning solution, etc.

[0003] In recent years, titanium nitride has been widely used as a hard mask. In addition, copper, cobalt, tungsten, etc. are used for metal wiring.

[0004] In a semiconductor substrate using titanium nitride as a hard mask and having metal wiring, a low-k interlayer insulating film and titanium nitride coexisting on the surface, it is required to remove the titanium nitride without corroding the metal wiring and the low-k interlayer insulating film.

[0005] As a method for removing titanium nitride by wet etching without corroding metal wiring, a cleaning method using an anticorrosive agent has been studied.

[0006] For example, Patent Document 1 discloses a liquid composition for the purpose of removing titanium nitride without corroding tungsten, etc., which comprises an oxidant containing potassium permanganate, a fluorine compound and a tungsten corrosion inhibitor, wherein the tungsten corrosion inhibitor is two compounds such as alkylamine, and the pH value of the liquid composition is 0 to 4.

[0007] Patent Document 2 discloses a composition containing an oxidizing agent, an etching solution, and a solvent, and containing substantially no hydrogen peroxide, for the purpose of selectively removing titanium nitride and photoresist etching residue materials.

[0008] Patent Document 3 discloses a composition for the purpose of selectively removing titanium nitride and photoresist etching residues, the composition comprising an oxidant, an etchant, a corrosion inhibitor, a silicon dioxide source, water, and an organic solvent, and substantially containing no hydrogen peroxide.

[0009] Patent Document 4 discloses a composition containing an oxidizing agent, an etching agent, a metal anticorrosive agent, a chelating agent, and a solvent for the purpose of selectively removing titanium nitride and photoresist etching residue materials from the surface of a microelectronic device.

[0010] Prior art literature

[0011] Patent Literature

[0012] Patent Document 1: International Publication No. 2015 / 111684

[0013] Patent Document 2: Japanese Patent Application No. 2015-506583

[0014] Patent Document 3: Japanese Patent Application No. 2016-510175

[0015] Patent Document 4: Japanese Patent Application No. 2016-527707 Summary of the invention

[0016] Problem that the invention aims to solve

[0017] As semiconductor elements become more integrated, the metal wiring of semiconductor substrates is also required to be miniaturized. As metal wiring becomes miniaturized, there is a concern that the metal atoms that form the wiring will diffuse into the semiconductor element. Under such circumstances, the use of molybdenum, which has low atomic diffusion, for metal wiring has been studied. However, molybdenum and its oxide film are highly water-soluble, and the previous preservatives have little effect on preventing molybdenum corrosion.

[0018] For example, if the amount of the oxidant used in the liquid composition disclosed in Patent Document 1 is reduced, the corrosion of molybdenum is suppressed. However, the removal rate of titanium nitride is reduced. If the amount of fluorine compound is increased to compensate for this phenomenon, corrosion of the low dielectric constant interlayer insulating film composed of silicon dioxide and the like occurs. Thus, in the manufacture of semiconductor substrates using molybdenum in metal wiring and titanium nitride in hard mask, it is difficult to remove titanium nitride in a manner that does not corrode the metal wiring and the low dielectric constant interlayer insulating film. Therefore, in the manufacture of semiconductor substrates using molybdenum in metal wiring and titanium nitride in hard mask, a composition for cleaning semiconductor substrates that can remove titanium nitride in a manner that does not corrode the metal wiring and the low dielectric constant interlayer insulating film is required.

[0019] The problem to be solved by the present invention is to provide a semiconductor substrate cleaning composition capable of selectively removing titanium nitride from a semiconductor substrate having titanium nitride, molybdenum and a low dielectric constant interlayer insulating film, a semiconductor substrate cleaning method using the semiconductor substrate cleaning composition, and a semiconductor substrate manufacturing method.

[0020] Solutions for solving problems

[0021] The present invention provides the following semiconductor substrate cleaning composition, semiconductor substrate cleaning method, and semiconductor substrate manufacturing method.

[0022] <1> A semiconductor substrate cleaning composition comprising:

[0023] Component (A): at least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base,

[0024] [MF n ] (n-k)- (a)

[0025] Component (B): a compound represented by the following general formula (b),

[0026] [MO m (OR) k-2m ] x (b)

[0027] (In formula (a) and formula (b), M is at least one element selected from the group consisting of boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus and titanium, k is the oxidation number of M, m is an integer from 0 to k / 2, x is a positive integer, R is one selected from the group consisting of a hydrogen atom, an alkali metal and an alkyl group, and n is the coordination number of the fluoride ion with respect to M.)

[0028] Component (C): oxidizing agent, and

[0029] Ingredients (D): Water,

[0030] α represented by the following formula (I) is 0.2 or more and 1.1 or less.

[0031]

[0032] (In formula (I), [F] is the molar concentration of fluoride ions in the aforementioned composition, [M] is the molar concentration of M in the aforementioned composition, and n(M) is the coordination number of fluoride ions with respect to M.)

[0033] <2> The semiconductor substrate cleaning composition according to <1>, wherein component (A) comprises at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, tetrafluoroboric acid, hexafluorozirconic acid, hexafluorotitanic acid, hexafluorophosphoric acid, salts of hexafluorosilicic acid, salts of tetrafluoroboric acid, salts of hexafluorozirconic acid, salts of hexafluorotitanic acid, and salts of hexafluorophosphoric acid.

[0034] <3> The semiconductor substrate cleaning composition according to <1> or <2>, wherein component (B) comprises at least one selected from the group consisting of boric acid, boric acid salts, silicon dioxide, silicic acid, silicic acid salts, orthosilicic acid, orthosilicic acid salts, alkoxysilane, zirconium oxide, zirconic acid and zirconic acid salts.

[0035] <4> A semiconductor substrate cleaning composition according to any one of <1> to <3>, wherein component (C) is at least one selected from the group consisting of vanadium (V) oxide, vanadic acid (V), salts of vanadic acid (V), permanganic acid, salts of permanganic acid, iodic acid, salts of iodic acid, orthoperiodic acid, salts of orthoperiodic acid, perchloric acid, salts of perchloric acid, ammonium cerium (IV) nitrate, ammonium iron (III) sulfate, ammonium persulfate, iron (III) chloride, ammonium nitrate, tert-butyl hydroperoxide, N-methylmorpholine N-oxide, and trimethylamine N-oxide.

[0036] <5> The semiconductor substrate cleaning composition according to any one of <1> to <4>, which does not substantially contain hydrogen peroxide, p-benzoquinone, copper (II) nitrate, sodium perborate, bromic acid or a salt of bromic acid.

[0037] <6> The semiconductor substrate cleaning composition according to any one of <1> to <5>, wherein the pH of the semiconductor substrate cleaning composition is 2 or less.

[0038] <7> The semiconductor substrate cleaning composition according to any one of <1> to <6>, which is used for removing titanium nitride from a semiconductor substrate having titanium nitride, molybdenum, and a low dielectric constant interlayer insulating film.

[0039] <8> The semiconductor substrate cleaning composition according to any one of <1> to <7>, wherein the content of the component (A) is 0.5 to 10% by mass based on the total amount of the semiconductor substrate cleaning composition.

[0040] <9> The semiconductor substrate cleaning composition according to any one of <1> to <8>, wherein the content of the component (B) is 0.05 to 10% by mass based on the total amount of the semiconductor substrate cleaning composition.

[0041] <10> The semiconductor substrate cleaning composition according to any one of <1> to <9>, wherein the content of the component (C) is 0.0005 to 1% by mass based on the total amount of the semiconductor substrate cleaning composition.

[0042] <11> A semiconductor substrate cleaning composition according to any one of <1> to <10>, wherein component (A) is at least one selected from the group consisting of an acid having an anion represented by the aforementioned general formula (a) as a conjugate base and a salt of an acid having an anion represented by the aforementioned general formula (a) as a conjugate base, and the ratio of the content (molar) of component (A) to the content (molar) of component (B) [(A) / (B)] is 1 to 100.

[0043] <12> A semiconductor substrate cleaning composition according to any one of <1> to <11>, wherein when a substrate having molybdenum and titanium nitride is immersed in the semiconductor substrate cleaning composition and stored at 60°C, titanium nitride can be removed at a removal rate of more than 30 angstroms / minute, and the ratio of the removal rate of titanium nitride to the removal rate of molybdenum is more than 3.

[0044] <13> A semiconductor substrate cleaning composition according to any one of <1> to <12>, wherein when a substrate having a low dielectric constant interlayer insulating film and titanium nitride is immersed in the aforementioned semiconductor substrate cleaning composition and stored at 60°C, the titanium nitride can be removed at a removal rate of more than 30 angstroms / minute, and the ratio of the removal rate of titanium nitride to the removal rate of the low dielectric constant interlayer insulating film is more than 10.

[0045] <14> The semiconductor substrate cleaning composition according to any one of <7> to <13>, wherein the low dielectric constant interlayer insulating film is a PE-TEOS film.

[0046] <15> A method for cleaning a semiconductor substrate, comprising bringing the semiconductor substrate cleaning composition according to any one of <1> to <14> into contact with a substrate having titanium nitride, molybdenum, and a low dielectric constant interlayer insulating film.

[0047] <16> A method for manufacturing a semiconductor substrate, comprising the step of bringing the semiconductor substrate cleaning composition according to any one of <1> to <14> into contact with a substrate having titanium nitride, molybdenum, and a low dielectric constant interlayer insulating film.

[0048] Effects of the Invention

[0049] The semiconductor substrate cleaning composition of the present invention can selectively remove titanium nitride from a semiconductor substrate having titanium nitride, molybdenum, and a low-dielectric-constant interlayer insulating film.

[0050] That is, by using the semiconductor substrate cleaning composition of the present invention, it is possible to remove titanium nitride while suppressing the corrosion of molybdenum, which has a low effect as an anticorrosive agent.

[0051] Therefore, a semiconductor substrate with miniaturized metal wiring can be cleaned and manufactured, and semiconductor elements can be highly integrated. DETAILED DESCRIPTION

[0052] The present invention provides a semiconductor substrate cleaning composition, a cleaning method using the semiconductor substrate cleaning composition, and a method for manufacturing a semiconductor substrate.

[0053] The semiconductor substrate cleaning composition comprises:

[0054] Component (A): at least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base,

[0055] [MF n ] (n-k)- (a)

[0056] Component (B): a compound represented by the following general formula (b),

[0057] [MO m (OR) k-2m ] x (b)

[0058] (In formula (a) and formula (b), M is at least one element selected from the group consisting of boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus and titanium, k is the oxidation number of M, m is an integer from 0 to k / 2, x is a positive integer, R is one selected from the group consisting of a hydrogen atom, an alkali metal and an alkyl group, and n is the coordination number of the fluoride ion with respect to M.)

[0059] Component (C): oxidizing agent, and

[0060] Ingredients (D): Water,

[0061] α represented by the following formula (I) is 0.2 or more and 1.1 or less.

[0062]

[0063] (In formula (I), [F] is the molar concentration of fluoride ions in the aforementioned composition, [M] is the molar concentration of M in the aforementioned composition, and n(M) is the coordination number of fluoride ions with respect to M.)

[0064] [Semiconductor substrate cleaning composition]

[0065] The semiconductor substrate cleaning composition of the present invention comprises:

[0066] Component (A): at least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base,

[0067] [MF n ] (n-k)- (a)

[0068] Component (B): a compound represented by the following general formula (b),

[0069] [MO m (OR) k-2m ] x (b)

[0070] (In formula (a) and formula (b), M is at least one element selected from the group consisting of boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus and titanium, k is the oxidation number of M, m is an integer from 0 to k / 2, x is a positive integer, R is one selected from the group consisting of a hydrogen atom, an alkali metal and an alkyl group, and n is the coordination number of the fluoride ion with respect to M.)

[0071] Component (C): oxidizing agent, and

[0072] Ingredients (D): Water,

[0073] α represented by the following formula (I) is 0.2 or more and 1.1 or less.

[0074]

[0075] (In formula (I), [F] is the molar concentration of fluoride ions in the aforementioned composition, [M] is the molar concentration of M in the aforementioned composition, and n(M) is the coordination number of fluoride ions with respect to M.)

[0076] The semiconductor substrate cleaning composition of the present invention can selectively remove titanium nitride from a semiconductor substrate having titanium nitride, molybdenum and a low dielectric constant interlayer insulating film by containing the above components and the above α being a specific value. The reason for having such excellent properties is not yet clear, but it is considered as follows.

[0077] The fluoride ions constituting the aforementioned component (A) are necessary for removing titanium nitride, but they also corrode molybdenum and low dielectric constant interlayer insulating films. It is believed that the semiconductor substrate cleaning composition of the present invention contains a compound having a specific element as a central element as component (B) in a manner that conforms to the aforementioned specific value of α, thereby appropriately reducing the nucleophilicity of the fluorine compound, thereby being able to remove titanium nitride and inhibit corrosion of molybdenum and the like.

[0078] The semiconductor substrate cleaning composition of the present invention will be described in detail below.

[0079] <Ingredients (A)>

[0080] The semiconductor substrate cleaning composition of the present invention comprises component (A), wherein component (A) is at least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base.

[0081] [MF n ] (n-k)- (a)

[0082] (In formula (a), M is at least one element selected from the group consisting of boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus and titanium, k is the oxidation number of M, and n is the coordination number of the fluoride ion with respect to M.)

[0083] That is, component (A) is at least one selected from the group consisting of hydrofluoric acid, salts of hydrofluoric acid, acids having an anion represented by the general formula (a) as a conjugate base, and salts of acids having an anion represented by the general formula (a) as a conjugate base.

[0084] Component (A) has a function of releasing fluoride ions during cleaning and assisting in the removal of titanium nitride.

[0085] Among these, at least one selected from the group consisting of hydrofluoric acid and an acid having an anion represented by the above general formula (a) as a conjugate base is preferred, and an acid having an anion represented by the above general formula (a) as a conjugate base is more preferred.

[0086] Examples of the salt of hydrofluoric acid include sodium fluoride, potassium fluoride, ammonium fluoride, acidic sodium fluoride, acidic potassium fluoride, and acidic ammonium fluoride.

[0087] In formula (a) representing the anion of the acid or its salt constituting the anion represented by the aforementioned general formula (a) as a conjugate base, M is at least one element selected from the group consisting of boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus and titanium, preferably at least one element selected from the group consisting of boron, silicon, zirconium, phosphorus and titanium, and more preferably at least one element selected from the group consisting of boron and silicon.

[0088] In addition, k is the oxidation number of M, and it differs depending on M. Generally, k is 3 for boron, 4 for silicon, 4 for zirconium, 5 for phosphorus, and 4 for titanium.

[0089] n is the coordination number of the fluoride ion to M, and varies depending on M. Generally, n is 4 for boron, 6 for silicon, 6 for zirconium, 6 for phosphorus, and 6 for titanium.

[0090] Examples of the acid having the anion represented by the general formula (a) as a conjugate base include hexafluorosilicic acid, tetrafluoroboric acid, hexafluorozirconic acid, hexafluoroantimonic acid, hexafluoroniobic acid, hexafluoroaluminic acid, hexafluorotitanic acid, and hexafluorophosphoric acid.

[0091] Examples of the salt of an acid having the anion represented by the general formula (a) as a conjugate base include salts of hexafluorosilicic acid, tetrafluoroboric acid, hexafluorozirconic acid, hexafluoroantimonic acid, hexafluoroniobic acid, hexafluoroaluminic acid, hexafluorotitanic acid, and hexafluorophosphoric acid.

[0092] As cations constituting the above-mentioned salts, for example, sodium ions, potassium ions, and ammonium ions can be cited. That is, as salts of acids with anions represented by the above-mentioned general formula (a) as conjugate bases, salts obtained by replacing the hydrogen ions of the respective acids with the above-mentioned cations can be cited. As an example of a specific salt, ammonium hexafluorophosphate can be cited.

[0093] From the viewpoint of balancing the removal of titanium nitride and the inhibition of corrosion of molybdenum and the low dielectric constant interlayer insulating film, component (A) preferably includes at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, tetrafluoroboric acid, hexafluorozirconic acid, hexafluorotitanic acid, hexafluorophosphoric acid, salts of hexafluorosilicic acid, salts of tetrafluoroboric acid, salts of hexafluorozirconic acid, salts of hexafluorotitanic acid and salts of hexafluorophosphoric acid, more preferably includes at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, tetrafluoroboric acid, hexafluorozirconic acid, hexafluorotitanic acid and hexafluorophosphoric acid, further preferably includes at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid and tetrafluoroboric acid, and further preferably includes at least one selected from the group consisting of hexafluorosilicic acid and tetrafluoroboric acid.

[0094] Furthermore, as a suitable embodiment, it is preferably at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, tetrafluoroboric acid, hexafluorozirconic acid, hexafluorotitanic acid, hexafluorophosphoric acid, salts of hexafluorosilicic acid, salts of tetrafluoroboric acid, salts of hexafluorozirconic acid, salts of hexafluorotitanic acid and salts of hexafluorophosphoric acid, more preferably at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, tetrafluoroboric acid, hexafluorozirconic acid, hexafluorotitanic acid and hexafluorophosphoric acid, further preferably at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid and tetrafluoroboric acid, and further preferably at least one selected from the group consisting of hexafluorosilicic acid and tetrafluoroboric acid.

[0095] The semiconductor substrate cleaning composition of the present invention may contain only one component (A) or two or more thereof. For example, it may contain both hydrofluoric acid and an acid having an anion represented by the general formula (a) as a conjugate base, or it may contain two or more of the acids having an anion represented by the general formula (a) as a conjugate base.

[0096] The content of component (A) in the semiconductor substrate cleaning composition of the present invention is preferably 0.5 to 10% by mass, more preferably 1.0 to 8.0% by mass, further preferably 2.0 to 7.0% by mass, and further preferably 3.0 to 6.0% by mass relative to the total amount of the semiconductor substrate cleaning composition. When the content of component (A) is within the above range, corrosion of molybdenum and low dielectric constant interlayer insulating films can be suppressed and titanium nitride can be removed.

[0097] <Ingredient (B)>

[0098] The semiconductor substrate cleaning composition of the present invention contains a compound component (B) represented by the following general formula (b).

[0099] [MO m (OR) k-2m ] x (b)

[0100] (In formula (b), M is at least one element selected from the group consisting of boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus and titanium, k is the oxidation number of M, m is an integer from 0 to k / 2, x is a positive integer, and R is one selected from the group consisting of a hydrogen atom, an alkali metal and an alkyl group.)

[0101] It is considered that the component (B) can achieve both removal of titanium nitride and corrosion suppression of molybdenum and the low dielectric constant interlayer insulating film by appropriately reducing the nucleophilicity of the component (A).

[0102] In formula (b) representing the compound of component (B), M is at least one element selected from the group consisting of boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus and titanium, preferably at least one element selected from the group consisting of boron, silicon, zirconium, phosphorus and titanium, and more preferably at least one element selected from the group consisting of boron and silicon.

[0103] In addition, k is the oxidation number of M, and it differs depending on M. Generally, k is 3 for boron, 4 for silicon, 4 for zirconium, 5 for phosphorus, and 4 for titanium.

[0104] R is one selected from the group consisting of a hydrogen atom, an alkali metal and an alkyl group. That is, if R is a hydrogen atom, component (B) is a compound having a hydroxyl group, if R is an alkali metal, component (B) is a salt of an acid having M as a central metal, and if R is an alkyl group, component (B) is an alkoxide.

[0105] m is an integer of 0 or more and k / 2 or less. When m is k / 2, component (B) is an oxide of M.

[0106] x is a positive integer. When x is 1, component (B) is a compound having one M in the molecule. When x is 2 or more, component (B) is a polymer formed by bonding a plurality of compounds having one M in the molecule. When x is 2 or more, component (B) preferably has a cyclic structure.

[0107] From the viewpoint of achieving both removal of titanium nitride and corrosion inhibition of molybdenum and low dielectric constant interlayer insulating films, component (B) preferably comprises at least one selected from the group consisting of boric acid, boric acid salts, silicon dioxide, silicic acid, silicic acid salts, orthosilicic acid, orthosilicic acid salts, alkoxysilanes, zirconium oxide, zirconic acid and zirconic acid salts, more preferably comprises at least one selected from the group consisting of boric acid, silicon dioxide, silicic acid and silicic acid salts, further preferably comprises at least one selected from the group consisting of boric acid, silicon dioxide and silicic acid salts, and further preferably comprises at least one selected from the group consisting of boric acid and silicic acid salts.

[0108] Furthermore, as a more suitable embodiment, component (B) is preferably at least one selected from the group consisting of boric acid, a salt of boric acid, silica, silicic acid, a salt of silicic acid, orthosilicic acid, a salt of orthosilicic acid, alkoxysilane, zirconium oxide, zirconic acid and a salt of zirconic acid, more preferably at least one selected from the group consisting of boric acid, silica, silicic acid and a salt of silicic acid, further preferably at least one selected from the group consisting of boric acid, silica and a salt of silicic acid, and further preferably at least one selected from the group consisting of boric acid and a salt of silicic acid.

[0109] Examples of cations constituting the salts include sodium ions, potassium ions, and ammonium ions. In other words, examples of boric acid salts, silicic acid salts, orthosilicic acid salts, and zirconic acid salts include salts obtained by replacing the hydrogen ions of the acids with the cations described above. Examples of specific salts include sodium metasilicate and potassium silicate.

[0110] The semiconductor substrate cleaning composition of the present invention may contain only one component (B) or two or more components.

[0111] The content of component (B) in the semiconductor substrate cleaning composition of the present invention is preferably 0.05 to 10% by mass, more preferably 0.1 to 5.0% by mass, further preferably 0.2 to 4.0% by mass, and further preferably 0.3 to 2.0% by mass relative to the total amount of the semiconductor substrate cleaning composition. When the content of component (B) is within the above range, corrosion of molybdenum and low dielectric constant interlayer insulating films can be suppressed and titanium nitride can be removed.

[0112] <Ingredient (C): Oxidant>

[0113] The semiconductor substrate cleaning composition of the present invention contains the component (C) as an oxidizing agent.

[0114] Component (C) is included in the composition in order to effectively remove titanium nitride.

[0115] As the component (C), a generally known oxidizing agent can be used.

[0116] Among them, from the viewpoint of taking into account both the removal of titanium nitride and the corrosion suppression of molybdenum and the low dielectric constant interlayer insulating film, component (C) is preferably selected from the group consisting of vanadium (V) oxide, vanadic acid (V), salts of vanadic acid (V), permanganic acid, salts of permanganic acid, iodic acid, salts of iodic acid, orthoperiodic acid, salts of orthoperiodic acid, perchloric acid, salts of perchloric acid, ammonium cerium (IV) nitrate, ammonium iron (III) sulfate, ammonium persulfate, iron (III) chloride, ammonium nitrate, tert-butyl hydroperoxide, N-methylmorpholine N-oxide, and trimethylamine N-oxide. At least one of the group consisting of vanadium (V) oxide, permanganate salts, iodic acid, iodic acid salts, perchloric acid, perchloric acid salts, ammonium cerium (IV) nitrate, ammonium iron (III) sulfate, ammonium persulfate, ammonium nitrate, and N-methylmorpholine N-oxide is more preferably at least one of the group consisting of vanadium (V) oxide, permanganate salts, and iodic acid, further preferably at least one of the group consisting of vanadium (V) oxide, permanganate salts, and iodic acid, further preferably at least one of the group consisting of vanadium (V) oxide and permanganate salts, further preferably a permanganate salt.

[0117] As cations constituting the above-mentioned salts, sodium ions, potassium ions, and ammonium ions can be cited. That is, as salts of vanadic acid (V), salts of permanganic acid, salts of iodic acid, salts of orthoperiodic acid, and salts of perchloric acid, salts obtained by replacing the hydrogen ions of each acid with the above-mentioned cations can be cited. As an example of a specific salt, potassium permanganate can be cited.

[0118] The semiconductor substrate cleaning composition of the present invention may contain only one component (C) or two or more components.

[0119] The content of the component (C) in the semiconductor substrate cleaning composition of the present invention is preferably 0.0005 to 1% by mass, more preferably 0.0008 to 0.2% by mass, further preferably 0.0010 to 0.1% by mass, further preferably 0.0010 to 0.03% by mass, further preferably 0.0015 to 0.01% by mass, relative to the total amount of the semiconductor substrate cleaning composition. When the content of the component (C) is within the above range, corrosion of molybdenum and the low dielectric constant interlayer insulating film can be suppressed and titanium nitride can be removed.

[0120] The semiconductor substrate cleaning composition of the present invention aims to suppress the corrosion of molybdenum and low dielectric constant interlayer insulating films during cleaning, so it is preferred not to use a strong oxidizing agent as much as possible, and even if used, it is preferred to use only a very small amount.

[0121] The semiconductor substrate cleaning composition of the present invention preferably does not substantially contain hydrogen peroxide, p-benzoquinone, copper (II) nitrate, sodium perborate, bromic acid or a salt of bromic acid. "Substantially not containing" means that the content is less than the amount that does not impair the effect of the semiconductor substrate cleaning composition of the present invention.

[0122] When hydrogen peroxide, p-benzoquinone, copper (II) nitrate, sodium perborate, bromic acid or a salt of bromic acid is contained, their total content relative to the total amount of the semiconductor substrate cleaning composition is preferably less than 0.0015% by mass, more preferably less than 0.0010% by mass, further preferably less than 0.0008% by mass, further preferably less than 0.0005% by mass, and further preferably, hydrogen peroxide, p-benzoquinone, copper (II) nitrate, sodium perborate, bromic acid or a salt of bromic acid is not contained.

[0123] <Ingredient (D): Water>

[0124] The semiconductor substrate cleaning composition of the present invention contains a component (D) which is water.

[0125] The water is not particularly limited, but is preferably water from which impurities such as metal ions, organic matter, and particles have been removed by distillation, ion exchange treatment, filtration treatment, or various adsorption treatments. Pure water is more preferred, and ultrapure water is particularly preferred.

[0126] The water content is the residual portion after removing the aforementioned component (A), the aforementioned component (B), the aforementioned component (C) and other additives from the semiconductor substrate cleaning composition of the present invention, and is preferably 80% by mass or more, more preferably 90 to 99.5% by mass, relative to the total amount of the semiconductor substrate cleaning composition. When the water content is within the above range, the effects of the present invention can be exerted and it is more economical.

[0127] <Characteristics, etc. of the semiconductor substrate cleaning composition>

[0128] The semiconductor substrate cleaning composition of the present invention comprises the above-mentioned components (A), (B), (C) and (D), wherein α represented by the following formula (I) is 0.2 or more and 1.1 or less.

[0129]

[0130] (In formula (I), [F] is the molar concentration of fluoride ions in the aforementioned composition, [M] is the molar concentration of M in the aforementioned composition, and n(M) is the coordination number of fluoride ions with respect to M.)

[0131] Here, α is a value represented by the aforementioned formula (I), and is a value indicating the ratio of the fluoride ions contained in the aforementioned component (A) to the element represented by M contained in the components (A) and (B).

[0132] It is believed that by setting α to a range of greater than 0.2 and less than 1.1, the elements contained in component (B) form a fluorine complex (acid complex coordinated with fluorine) with the fluoride ions contained in component (A), and fluoride ions are gradually supplied due to the equilibrium reaction, thereby appropriately reducing the nucleophilicity of the fluorine compound, thereby being able to remove titanium nitride and inhibit corrosion of molybdenum and the like.

[0133] α is 0.2 or more, preferably 0.4 or more, more preferably 0.7 or more, and is 1.1 or less, preferably 1.05 or less, more preferably 1.0 or less. When α is within the above range, corrosion of molybdenum and the low dielectric constant interlayer insulating film can be suppressed and titanium nitride can be removed.

[0134] In formula (I), α is obtained by dividing the molar concentration of fluoride ions in the composition ([F]) by the product of the coordination number of fluoride ions with respect to M (n(M)) and the molar concentration of M in the composition ([M]).

[0135] Here, M is an element used in component (A) and component (B), and specifically, is at least one element selected from the group consisting of boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus, and titanium.

[0136] When a plurality of elements M are used as components (A) and (B), α is calculated by dividing the molar concentration of fluoride ions in the composition ([F]) by the sum of the products of the coordination number of fluoride ions for each M (n(M)) and the molar concentration of each M in the composition.

[0137] For example, when M includes two types of M, M1 and M2, the denominator on the right side of the above formula (I) becomes (n1(M1)·[M1]+n2(M2)·[M2]). Here, [M1] is the molar concentration of M1 in the composition, n1(M1) is the coordination number of the fluoride ion with respect to M1, [M2] is the molar concentration of M2 in the composition, and n2(M2) is the coordination number of the fluoride ion with respect to M2.

[0138] When the component (A) is at least one selected from the group consisting of an acid having an anion represented by the above general formula (a) as a conjugate base and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base, the ratio of the content (molar) of the component (A) to the content (molar) of the component (B) [(A) / (B)] is preferably 1 to 100, more preferably 2 to 50, further preferably 4 to 40, further preferably 4 to 20, further preferably 8 to 20. When the ratio of the molar content of the component (A) to the molar content of the component (B) is within the above range, corrosion of molybdenum and low dielectric constant interlayer insulating films can be suppressed and titanium nitride can be removed. The above "ratio of the content (molar) of the component (A) to the content (molar) of the component (B)" is "the ratio of the content (molar) of the component (A) to the content (molar) of the component (B) [(A) / (B)]".

[0139] It should be noted that when x in formula (b) representing the compound of component (B) exceeds 1, the "content (mole) of component (B)" when calculating the above ratio is the amount obtained by multiplying the actual content of component (B) contained in the semiconductor substrate cleaning composition by x.

[0140] The pH of the semiconductor substrate cleaning composition of the present invention is preferably 2 or less, more preferably 1.5 or less, further preferably 1.0 or less, and further preferably 0.5 or less. When the pH is within the above range, the corrosion of molybdenum can be particularly suppressed. The pH can be measured by the method described in the examples.

[0141] As described above, the semiconductor substrate cleaning composition of the present invention is used to remove titanium nitride from a semiconductor substrate having titanium nitride, molybdenum, and a low dielectric constant interlayer insulating film. That is, the semiconductor substrate cleaning composition of the present invention is a semiconductor substrate cleaning composition for removing titanium nitride from a semiconductor substrate having titanium nitride, molybdenum, and a low dielectric constant interlayer insulating film.

[0142] More specifically, the semiconductor substrate cleaning composition of the present invention is a semiconductor substrate cleaning composition for removing titanium nitride from a semiconductor substrate having titanium nitride, molybdenum and a low dielectric constant interlayer insulating film, and comprises:

[0143] Component (A): at least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base,

[0144] [MF n ] (n-k)- (a)

[0145] Component (B): a compound represented by the following general formula (b),

[0146] [MOm (OR) k-2m ] x (b)

[0147] (In formula (a) and formula (b), M is at least one element selected from the group consisting of boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus and titanium, k is the oxidation number of M, m is an integer from 0 to k / 2, x is a positive integer, R is one selected from the group consisting of a hydrogen atom, an alkali metal and an alkyl group, and n is the coordination number of the fluoride ion with respect to M.)

[0148] Component (C): oxidizing agent, and

[0149] Ingredients (D): Water,

[0150] α represented by the following formula (I) is 0.2 or more and 1.1 or less.

[0151]

[0152] (In formula (I), [F] is the molar concentration of fluoride ions in the aforementioned composition, [M] is the molar concentration of M in the aforementioned composition, and n(M) is the coordination number of fluoride ions with respect to M.)

[0153] The semiconductor substrate cleaning composition of the present invention is preferably capable of removing titanium nitride at a removal rate of 30 angstroms / minute or more when a substrate having molybdenum and titanium nitride is immersed in the aforementioned semiconductor substrate cleaning composition and stored at 60°C, and the ratio of the titanium nitride removal rate to the molybdenum removal rate is 3 or more.

[0154] The semiconductor substrate cleaning composition of the present invention can selectively remove titanium nitride from a semiconductor substrate having molybdenum by having the above-mentioned properties. That is, by using the semiconductor substrate cleaning composition of the present invention, it is possible to suppress the corrosion of molybdenum, which has a low effect as an anticorrosive agent, and remove titanium nitride. Therefore, a semiconductor substrate with miniaturized metal wiring can be cleaned and manufactured, and semiconductor elements can be highly integrated.

[0155] The removal rate of titanium nitride under the above conditions is preferably 30 angstroms / minute or more, more preferably 100 angstroms / minute or more, and further preferably 150 angstroms / minute or more. The greater the removal rate of titanium nitride under the above conditions, the more efficiently titanium nitride can be removed, and therefore it is preferred, but is usually 2000 angstroms / minute or less.

[0156] The removal rate of molybdenum under the aforementioned conditions is preferably 50 angstroms / minute or less, more preferably 30 angstroms / minute or less, and further preferably 25 angstroms / minute or less. The smaller the removal rate of molybdenum under the aforementioned conditions, the more the corrosion of molybdenum can be suppressed, so it is preferred, but is usually 0.1 angstroms / minute or more.

[0157] The ratio of the removal rate of titanium nitride to the removal rate of molybdenum under the aforementioned conditions is preferably 3 or more, more preferably 5 or more, and further preferably 8 or more. The larger the ratio of the removal rate of titanium nitride to the removal rate of molybdenum under the aforementioned conditions, the more selective removal of titanium nitride from the semiconductor substrate having molybdenum is possible, and therefore it is preferred, but is usually 300 or less.

[0158] The specific measurement method and conditions are described in "(2) Etching rate (ER)" of the Examples.

[0159] The semiconductor substrate cleaning composition of the present invention is preferably capable of removing titanium nitride at a removal rate of more than 30 angstroms / minute when a substrate having a low dielectric constant interlayer insulating film and titanium nitride is immersed in the aforementioned semiconductor substrate cleaning composition and stored at 60°C, and the ratio of the removal rate of titanium nitride to the removal rate of the low dielectric constant interlayer insulating film is more than 10.

[0160] The semiconductor substrate cleaning composition of the present invention has the above-mentioned properties and can selectively remove titanium nitride from a semiconductor substrate having a low dielectric constant interlayer insulating film. Therefore, a semiconductor substrate with miniaturized metal wiring can be cleaned and manufactured, and semiconductor elements can be highly integrated.

[0161] The removal rate of titanium nitride under the above conditions is preferably 30 angstroms / minute or more, more preferably 100 angstroms / minute or more, and further preferably 150 angstroms / minute or more. The greater the removal rate of titanium nitride under the above conditions, the more efficiently titanium nitride can be removed, and therefore it is preferred, but is usually 2000 angstroms / minute or less.

[0162] The removal rate of the low dielectric constant interlayer insulating film under the above conditions is preferably 15 angstroms / minute or less, more preferably 10 angstroms / minute or less, and further preferably 6 angstroms / minute or less. The lower the removal rate of the low dielectric constant interlayer insulating film under the above conditions, the more selectively titanium nitride can be removed from the semiconductor substrate having the low dielectric constant interlayer insulating film, and thus it is preferred, but is usually 0.1 angstroms / minute or more.

[0163] The ratio of the removal rate of titanium nitride to the removal rate of the low dielectric constant interlayer insulating film under the aforementioned conditions is preferably greater than 10, more preferably greater than 30, and further preferably greater than 90. The greater the ratio of the removal rate of titanium nitride to the removal rate of the low dielectric constant interlayer insulating film under the aforementioned conditions, the more selectively titanium nitride can be removed from the semiconductor substrate having the low dielectric constant interlayer insulating film, and therefore it is preferred, but is usually less than 500.

[0164] The specific measurement method and conditions are described in "(2) Etching rate (ER)" of the Examples.

[0165] The low dielectric constant interlayer insulating film is preferably a film containing a silicon compound, more preferably a TEOS film, a silicon dioxide film, or a silicon-containing organic polymer film, further preferably a TEOS film or a silicon dioxide film, and still more preferably a TEOS film.

[0166] The silicon dioxide film is preferably a carbon-doped silicon dioxide film.

[0167] Among TEOS films, PE-TEOS film (plasma TEOS film) is preferred.

[0168] [Semiconductor substrate cleaning method]

[0169] The semiconductor substrate cleaning method of the present invention is a semiconductor substrate cleaning method comprising bringing the semiconductor substrate cleaning composition into contact with a substrate having titanium nitride, molybdenum and a low dielectric constant interlayer insulating film.

[0170] That is, the semiconductor substrate cleaning method of the present invention is a semiconductor substrate cleaning method comprising bringing the following semiconductor substrate cleaning composition into contact with a substrate having titanium nitride, molybdenum and a low dielectric constant interlayer insulating film.

[0171] The semiconductor substrate cleaning composition comprises:

[0172] Component (A): at least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base,

[0173] [MF n ] (n-k)- (a)

[0174] Component (B): a compound represented by the following general formula (b),

[0175] [MO m (OR) k-2m ] x (b)

[0176] (In formula (a) and formula (b), M is at least one element selected from the group consisting of boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus and titanium, k is the oxidation number of M, m is an integer from 0 to k / 2, x is a positive integer, R is one selected from the group consisting of a hydrogen atom, an alkali metal and an alkyl group, and n is the coordination number of the fluoride ion with respect to M.)

[0177] Component (C): oxidizing agent, and

[0178] Ingredients (D): Water,

[0179] α represented by the following formula (I) is 0.2 or more and 1.1 or less.

[0180]

[0181] (In formula (I), [F] is the molar concentration of fluoride ions in the aforementioned composition, [M] is the molar concentration of M in the aforementioned composition, and n(M) is the coordination number of fluoride ions with respect to M.)

[0182] The cleaning method of the present invention is performed to remove titanium nitride from a semiconductor substrate having titanium nitride, molybdenum and a low dielectric constant interlayer insulating film. The semiconductor substrate is cleaned by the cleaning method of the present invention, so that titanium nitride can be selectively removed from the semiconductor substrate having titanium nitride, molybdenum and a low dielectric constant interlayer insulating film.

[0183] That is, by cleaning the substrate using the cleaning method of the present invention, it is possible to suppress the corrosion of molybdenum, which has a low effect as an anticorrosive agent, and remove titanium nitride.

[0184] Therefore, a semiconductor substrate with miniaturized metal wiring can be cleaned and manufactured, and semiconductor elements can be highly integrated.

[0185] In the cleaning method of the present invention, the temperature during cleaning is not particularly limited, but is preferably 20 to 80° C., and more preferably 25 to 70° C. Ultrasonic waves may be used during cleaning.

[0186] In the cleaning method of the present invention, the cleaning time is not particularly limited, but is preferably 0.3 to 20 minutes, more preferably 0.5 to 10 minutes.

[0187] In the cleaning method of the present invention, it is further preferred to rinse with a rinse solution containing water, alcohol or the like after cleaning.

[0188] In the cleaning method of the present invention, the method for contacting the semiconductor substrate cleaning composition of the present invention with the substrate is not particularly limited. For example, a method of contacting the semiconductor substrate cleaning composition of the present invention with the substrate by dripping (single-wafer spinning process) or spraying (spraying process) or the like, or a method of immersing the substrate in the semiconductor substrate cleaning composition of the present invention, etc. can be used. In the present invention, any method can be used, preferably a method of immersing the substrate in the semiconductor substrate cleaning composition of the present invention.

[0189] [Method for manufacturing semiconductor substrate]

[0190] The method for manufacturing a semiconductor substrate of the present invention includes the step of bringing the semiconductor substrate cleaning composition into contact with a substrate having titanium nitride, molybdenum, and a low dielectric constant interlayer insulating film.

[0191] That is, the method for manufacturing a semiconductor substrate of the present invention includes the step of bringing the following semiconductor substrate cleaning composition into contact with a substrate having titanium nitride, molybdenum and a low dielectric constant interlayer insulating film,

[0192] The semiconductor substrate cleaning composition comprises:

[0193] Component (A): at least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base,

[0194] [MF n ] (n-k)- (a)

[0195] Component (B): a compound represented by the following general formula (b),

[0196] [MO m (OR) k-2m ] x (b)

[0197] (In formula (a) and formula (b), M is at least one element selected from the group consisting of boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus and titanium, k is the oxidation number of M, m is an integer from 0 to k / 2, x is a positive integer, R is one selected from the group consisting of a hydrogen atom, an alkali metal and an alkyl group, and n is the coordination number of the fluoride ion with respect to M.)

[0198] Component (C): oxidizing agent, and

[0199] Ingredients (D): Water,

[0200] α represented by the following formula (I) is 0.2 or more and 1.1 or less.

[0201]

[0202] (In formula (I), [F] is the molar concentration of fluoride ions in the aforementioned composition, [M] is the molar concentration of M in the aforementioned composition, and n(M) is the coordination number of fluoride ions with respect to M.)

[0203] A specific method for manufacturing a semiconductor substrate is as follows.

[0204] First, after a barrier insulating film, a low dielectric constant interlayer insulating film, a hard mask and a photoresist are stacked on a substrate such as silicon having a barrier metal, a metal wiring, a low dielectric constant interlayer insulating film and a metal cover as required, the photoresist is subjected to selective exposure and development treatment to form a photoresist pattern. Next, the photoresist pattern is transferred to the hard mask using dry etching. Then, the photoresist pattern is removed, and the low dielectric constant interlayer insulating film and the barrier insulating film are subjected to dry etching using the aforementioned hard mask as an etching mask. Next, a process of contacting the semiconductor substrate cleaning composition with the substrate as the aforementioned process is implemented to obtain a semiconductor substrate having a desired metal wiring pattern.

[0205] Here, as the substrate material, silicon, amorphous silicon, polycrystalline silicon, glass, etc. are used. As the barrier metal, tantalum, tantalum nitride, ruthenium, manganese, magnesium, cobalt, oxides thereof, etc. are used.

[0206] As described above, the low dielectric constant interlayer insulating film is preferably a film containing a silicon compound, more preferably a TEOS film, a silicon dioxide film, or a silicon-containing organic polymer film, further preferably a TEOS film or a silicon dioxide film, and still more preferably a TEOS film.

[0207] The silicon dioxide film is preferably a carbon-doped silicon dioxide film.

[0208] Among TEOS films, PE-TEOS film (plasma TEOS film) is preferred.

[0209] As the barrier insulating film, silicon nitride, silicon carbide, silicon carbide nitride, etc. are used. As the hard mask, titanium, titanium nitride, etc. are used. In the present invention, the hard mask contains titanium nitride.

[0210] The metal wiring contains molybdenum. The metal wiring may be a single substance of molybdenum or a molybdenum alloy, but is preferably a single substance of molybdenum.

[0211] The step of bringing the semiconductor substrate cleaning composition into contact with a substrate having titanium nitride, molybdenum and a low dielectric constant interlayer insulating film, which is a step included in the present manufacturing method, is preferably carried out under the same conditions as the cleaning method described in the aforementioned [Semiconductor substrate cleaning method].

[0212] According to the method for manufacturing a semiconductor substrate of the present invention, since it includes a step of using the semiconductor substrate cleaning composition to retain necessary components and remove unnecessary components, a semiconductor substrate with miniaturized metal wiring can be manufactured, and semiconductor elements can be highly integrated.

[0213] Example

[0214] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0215] <Analysis method / Evaluation method>

[0216] (1) pH

[0217] The pH of the semiconductor substrate cleaning composition was measured by a glass electrode method (manufactured by HORIBA: F-55S tabletop pH meter, manufactured by HORIBA: standard ToupH electrode 9165S-10D, temperature: 25°C).

[0218] (2) Etching rate (ER)

[0219] (2-1) Etching rate (ER) of titanium nitride and low dielectric constant interlayer insulation film

[0220] A "wafer with a titanium nitride film" having a titanium nitride layer on a silicon wafer and a "wafer with a TEOS film" having a plasma TEOS (PE-TEOS) layer as a type of low dielectric constant interlayer insulating film on a silicon wafer were prepared.

[0221] Next, the film thickness was measured. The film thickness of the titanium nitride layer of the "wafer with titanium nitride film" was measured using a fluorescent X-ray device SEA1200VX (manufactured by SII NanoTechnology Inc.). The film thickness of the PE-TEOS layer of the "wafer with TEOS film" was measured using an optical film thickness meter n&k1280 (manufactured by n&k Technology Inc.).

[0222] Next, the semiconductor substrate cleaning compositions of Examples and Comparative Examples were adjusted to 60° C., and the wafers with films were immersed therein for 1 to 5 minutes, followed by rinsing with ultrapure water at 25° C., and the film thickness of each wafer was measured again by the above-mentioned measurement method.

[0223] The difference in film thickness before and after immersion in the semiconductor substrate cleaning composition was divided by the treatment time to calculate the etching rate (ER) (angstroms / minute) of each material. In Table 1, titanium nitride is described as "TiN" and low dielectric constant interlayer insulating film is described as "TEOS".

[0224] (2-2) Determination of Molybdenum Etching Rate (ER)

[0225] A "wafer with a molybdenum film" having a PVD-filmed molybdenum layer on a silicon wafer is prepared.

[0226] The semiconductor substrate cleaning composition of the embodiment and the comparative example is adjusted to 60°C, and the wafer with the molybdenum film is immersed for 1 to 5 minutes. The cleaning liquid after immersion (referred to as "the composition used" in the following formula) is diluted 10 to 30 times with 1% by mass ammonia water, and the molybdenum concentration is measured using an inductively coupled plasma emission spectrometer iCAP DUO-6300 (manufactured by Thermo Fisher). The molybdenum concentration before dilution (Mo concentration) is calculated and substituted into the following formula to calculate the etching rate (ER) (angstroms / minute) of molybdenum. It is recorded as "Mo" in Table 1. It should be noted that in the following formula, "10.28 g / cm 3 ” is the density of molybdenum, and “wafer area” is the area of ​​the molybdenum film on the wafer.

[0227]

[0228] (3) Etching selectivity

[0229] The etching rate ratio was calculated from the etching rates obtained by the above method to evaluate the etching selectivity.

[0230] The obtained etching rate ratio is as follows.

[0231] (3-1) Etching rate ratio of titanium nitride to molybdenum (TiN / Mo)

[0232] In each of the Examples and Comparative Examples, the etching rate of titanium nitride (TiN) was divided by the etching rate of molybdenum (Mo) to obtain the etching rate ratio of titanium nitride to molybdenum (TiN / Mo). The larger the value, the more the semiconductor substrate cleaning composition can suppress the corrosion of molybdenum and remove titanium nitride. That is, the larger the value, the more the semiconductor substrate cleaning composition can selectively remove titanium nitride from a semiconductor substrate having molybdenum.

[0233] (3-2) Etching rate ratio of titanium nitride to low dielectric constant interlayer insulating film (TiN / TEOS)

[0234] In each embodiment and comparative example, the etching rate of titanium nitride (TiN) was divided by the etching rate of PE-TEOS (TEOS) to obtain the etching rate ratio (TiN / TEOS) of titanium nitride relative to plasma TEOS as a low dielectric constant interlayer insulating film. The larger the value, the more the semiconductor substrate cleaning composition can suppress the corrosion of the low dielectric constant interlayer insulating film and remove titanium nitride. That is, the larger the value, the more the semiconductor substrate cleaning composition can selectively remove titanium nitride from a semiconductor substrate having a low dielectric constant interlayer insulating film.

[0235] <Semiconductor substrate cleaning composition>

[0236] Example 1

[0237] Tetrafluoroboric acid (component (A)), boric acid (component (B)), potassium permanganate (component (C)), sulfuric acid, and ultrapure water (component (D)) were blended at the mass ratios shown in Table 1 to obtain a semiconductor substrate cleaning composition.

[0238] Examples 2 to 8 and Comparative Examples 1 to 7

[0239] The same method as in Example 1 was used to obtain a semiconductor substrate cleaning composition except that the components and mass ratios of Example 1 were changed to the components and mass ratios shown in Table 1. It should be noted that the component (B) was not added in Comparative Examples 4 to 7. In addition, sulfuric acid was not added in Examples 5 to 8 and Comparative Examples 1, 3, and 5 to 7.

[0240] Each semiconductor substrate cleaning composition was analyzed and evaluated using the method shown in the above-mentioned analysis method / evaluation method. Table 1 shows the analysis and evaluation results of the semiconductor substrate cleaning compositions obtained in Examples and Comparative Examples.

[0241] In Table 1, for convenience, component (A) is described as a fluorine compound, component (B) is described as a silicon compound, etc., and the molar ratio of component (A) to component (B) [(A) / (B)] is described.

[0242] [Table 1]

[0243] Table 1

[0244]

[0245] As can be seen from Table 1, the semiconductor substrate cleaning composition of the embodiment can selectively remove titanium nitride from a semiconductor substrate having titanium nitride, molybdenum, and a low dielectric constant interlayer insulating film. Therefore, it can be seen that by using the semiconductor substrate cleaning composition of the present invention, the corrosion of molybdenum, which has a small effect as an anticorrosive agent, can be particularly suppressed and titanium nitride can be removed. Therefore, the semiconductor substrate cleaning composition of the present invention is suitable for cleaning and manufacturing semiconductor substrates with miniaturized metal wiring.

Claims

1. A semiconductor substrate cleaning composition comprising: Component (A): at least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base, [MF] n ] (n-k)- (in) Component (B): a compound represented by the following general formula (b), [MO m (OR) k-2m ] x (b) In formula (a) and formula (b), M is at least one element selected from the group consisting of boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus and titanium, k is the oxidation number of M, m is an integer of 0 to k / 2, x is a positive integer, R is one selected from the group consisting of a hydrogen atom, an alkali metal and an alkyl group, and n is the coordination number of the fluoride ion with respect to M. Component (C): oxidizing agent, and Ingredients (D): Water, α represented by the following formula (I) is 0.2 or more and 1.1 or less, In formula (I), [F] is the molar concentration of fluoride ions in the composition, [M] is the molar concentration of M in the composition, and n(M) is the coordination number of fluoride ions with respect to M.

2. The semiconductor substrate cleaning composition according to claim 1, wherein Component (A) contains at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, tetrafluoroboric acid, hexafluorozirconic acid, hexafluorotitanic acid, hexafluorophosphoric acid, salts of hexafluorosilicic acid, salts of tetrafluoroboric acid, salts of hexafluorozirconic acid, salts of hexafluorotitanic acid, and salts of hexafluorophosphoric acid.

3. The semiconductor substrate cleaning composition according to claim 1 or 2, wherein Component (B) contains at least one selected from the group consisting of boric acid, boric acid salts, silicon dioxide, silicic acid, silicic acid salts, orthosilicic acid, orthosilicic acid salts, alkoxysilane, zirconium oxide, zirconic acid, and zirconic acid salts.

4. The semiconductor substrate cleaning composition according to any one of claims 1 to 3, wherein Component (C) is at least one selected from the group consisting of vanadium (V) oxide, vanadic acid (V), salts of vanadic acid (V), permanganic acid, salts of permanganic acid, iodic acid, salts of iodic acid, orthoperiodic acid, salts of orthoperiodic acid, perchloric acid, salts of perchloric acid, ammonium cerium (IV) nitrate, ammonium iron (III) sulfate, ammonium persulfate, iron (III) chloride, ammonium nitrate, tert-butyl hydroperoxide, N-methylmorpholine N-oxide, and trimethylamine N-oxide. 5 . The semiconductor substrate cleaning composition according to claim 1 , which does not substantially contain hydrogen peroxide, p-benzoquinone, copper (II) nitrate, sodium perborate, bromic acid or a salt of bromic acid.

6. The semiconductor substrate cleaning composition according to any one of claims 1 to 5, wherein The pH of the semiconductor substrate cleaning composition is 2 or less. 7 . The semiconductor substrate cleaning composition according to claim 1 , which is used for removing titanium nitride from a semiconductor substrate having titanium nitride, molybdenum, and a low-dielectric-constant interlayer insulating film.

8. The semiconductor substrate cleaning composition according to any one of claims 1 to 7, wherein The content of the component (A) is 0.5 to 10% by mass based on the total amount of the semiconductor substrate cleaning composition.

9. The semiconductor substrate cleaning composition according to any one of claims 1 to 8, wherein The content of the component (B) is 0.05 to 10% by mass based on the total amount of the semiconductor substrate cleaning composition.

10. The semiconductor substrate cleaning composition according to any one of claims 1 to 9, wherein The content of the component (C) is 0.0005 to 1% by mass based on the total amount of the semiconductor substrate cleaning composition.

11. The semiconductor substrate cleaning composition according to any one of claims 1 to 10, wherein Component (A) is at least one selected from the group consisting of an acid having an anion represented by the general formula (a) as a conjugate base and a salt of an acid having an anion represented by the general formula (a) as a conjugate base, and the ratio of the content (molar) of component (A) to the content (molar) of component (B) [(A) / (B)] is 1 to 100.

12. The semiconductor substrate cleaning composition according to any one of claims 1 to 11, wherein When a substrate having molybdenum and titanium nitride is immersed in the semiconductor substrate cleaning composition and stored at 60° C., titanium nitride can be removed at a removal rate of 30 angstroms / minute or more, and the ratio of the removal rate of titanium nitride to the removal rate of molybdenum is 3 or more.

13. The semiconductor substrate cleaning composition according to any one of claims 1 to 12, wherein When a substrate having a low dielectric constant interlayer insulating film and titanium nitride is immersed in the semiconductor substrate cleaning composition and stored at 60° C., titanium nitride can be removed at a removal rate of more than 30 angstroms / minute, and the ratio of the removal rate of titanium nitride to the removal rate of the low dielectric constant interlayer insulating film is more than 10.

14. The semiconductor substrate cleaning composition according to any one of claims 7 to 13, wherein The low dielectric constant interlayer insulating film is a PE-TEOS film. 15 . A method for cleaning a semiconductor substrate, comprising bringing the semiconductor substrate cleaning composition according to claim 1 into contact with a substrate having titanium nitride, molybdenum, and a low dielectric constant interlayer insulating film.

16. A method for manufacturing a semiconductor substrate, comprising the following steps: A step of bringing the semiconductor substrate cleaning composition according to any one of claims 1 to 14 into contact with a substrate having titanium nitride, molybdenum and a low dielectric constant interlayer insulating film.

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