Semiconductor substrate cleaning composition, method for cleaning semiconductor substrates, and method for producing semiconductor substrates

Abstract

This semiconductor substrate cleaning composition comprises: component (A) : at least one selection from the group consisting of hydrofluoric acid, salts of hydrofluoric acid, acids for which the conjugate base is an anion represented by formula (a), and salts of acids for which the conjugate base is an anion represented by formula (a), where (a): [MFn] (n-k)-; component (B) : a compound given by formula (b), where (b): [MOm (OR) k-2m] x (M is boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus, or titanium; k is the oxidation number for M; m is an integer from 0 to k / 2; x is a positive integer; R is a hydrogen atom, alkali metal, or alkyl group; and n is the coordination number of fluoride ions to M.);　component (C) : an oxidizing agent; and component (D) : water, wherein the α given by formula (I) is 0.2 to 1.1. ([F] is the molar concentration of fluoride ion in the composition, [M] is the molar concentration of M in the composition, and n(M) is the coordination number of fluoride ions to M.)

Description

Semiconductor substrate cleaning composition, semiconductor substrate cleaning method, and semiconductor substrate manufacturing method

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

[0002] In the manufacture of semiconductor substrates with highly integrated semiconductor elements, a typical process involves forming a conductive thin film, such as a metal film serving as conductive wiring, a low-dielectric-constant interlayer insulating film for insulating between the conductive thin films, a hard mask, and the like, on a substrate such as a silicon wafer. Then, a photoresist is uniformly applied to the surface to form a photosensitive layer, which is then selectively exposed to light and developed to form a desired photoresist pattern. Next, using this photoresist pattern as a mask, the substrate on which the low-dielectric-constant interlayer insulating film, hard mask, and the like are layered is subjected to a dry etching process to form a desired pattern on the substrate. A series of steps is then generally employed, in which the photoresist pattern and residues and hard masks generated by the dry etching process are removed by oxygen plasma ashing, cleaning solutions, or the like.

[0003] In recent years, titanium nitride has been widely used as a hard mask. Copper, cobalt, tungsten, etc. are also used for metal wiring. In semiconductor substrates where titanium nitride is used as a hard mask and coexists with metal wiring and low-k interlayer insulating films on the surface, there is a need to remove the titanium nitride without corroding the metal wiring or low-k interlayer insulating film. As a method for removing titanium nitride by wet etching without corroding the metal wiring, a cleaning method using an anticorrosive agent has been investigated.

[0004] For example, Patent Document 1 discloses a liquid composition having a pH of 0 to 4, which contains an oxidizing agent including potassium permanganate, a fluorine compound, and two types of tungsten corrosion inhibitors, such as alkylamines, for the purpose of removing titanium nitride without corroding tungsten and the like. Patent Document 2 discloses a composition containing an oxidizing agent, an etching solution, and a solvent, but substantially free of hydrogen peroxide, for the purpose of selectively removing titanium nitride and photoresist etching residue materials. Patent Document 3 discloses a composition containing an oxidizing agent, an etchant, a corrosion inhibitor, a silica source, water, an organic solvent, and substantially free of hydrogen peroxide, for the purpose of selectively removing titanium nitride and photoresist etching residue materials. Patent Document 4 discloses a composition containing an oxidizing agent, an etching agent, a metal corrosion inhibitor, 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.

[0005] International Publication No. 2015 / 111684 Special Publication No. 2015-506583 Special Publication No. 2016-510175 Special Publication No. 2016-527707

[0006] As semiconductor devices become more highly integrated, miniaturization of metal wiring on semiconductor substrates is also required. As metal wiring becomes more miniaturized, there are concerns about the diffusion of metal atoms forming the wiring into semiconductor devices. In light of this situation, the use of molybdenum, which has low atomic diffusion, for metal wiring has been considered. However, molybdenum and its oxide film are highly water-soluble, and conventional corrosion inhibitors are only effective in preventing molybdenum corrosion. For example, reducing the amount of oxidizer used in the liquid composition disclosed in Patent Document 1 suppresses molybdenum corrosion. However, the removal rate of titanium nitride decreases. If the amount of fluorine compound is increased to compensate for this, corrosion of low-dielectric-constant interlayer insulating films composed of silicon dioxide or the like occurs. Thus, in the manufacture of semiconductor substrates using molybdenum for metal wiring and titanium nitride for hard masks, it is extremely difficult to remove titanium nitride without corroding the metal wiring and low-dielectric-constant interlayer insulating film. Therefore, in the production of semiconductor substrates that use molybdenum for metal wiring and titanium nitride for hard masks, there has been a demand for a composition for cleaning semiconductor substrates that can remove titanium nitride without corroding the metal wiring or low-dielectric-constant interlayer insulating film.

[0007] 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 method for cleaning a semiconductor substrate using the semiconductor substrate cleaning composition, and a method for manufacturing a semiconductor substrate.

[0008] The present invention provides the following semiconductor substrate cleaning composition, semiconductor substrate cleaning method, and semiconductor substrate manufacturing method: <1> Component (A): at least one selected from the group consisting of hydrofluoric acid, salts of hydrofluoric acid, acids having an anion represented by the following general formula (a) as a conjugate base, and salts of acids having an anion represented by the following general formula (a) as a conjugate base, [MF n ] (n-k)- (a) Component (B): a compound represented by the following general formula (b): [MO m (OR) k-2m ] x(b) (In formulas (a) and (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 a fluoride ion with respect to M.) A composition for cleaning a semiconductor substrate, comprising: a component (C): an oxidizing agent; and a component (D): water, wherein α, as 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 <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 <1> or <2>, wherein the component (B) contains at least one selected from the group consisting of boric acid, a salt of boric acid, silicon dioxide, silicic acid, a salt of silicic acid, orthosilicic acid, a salt of orthosilicic acid, an alkoxysilane, zirconium oxide, zirconic acid, and a salt of zirconic acid. <4> The 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, vanadate(V), salts of vanadate(V), permanganic acid, salts of permanganate, iodic acid, salts of iodic acid, orthoperiodic acid, salts of orthoperiodic acid, perchloric acid, salts of perchloric acid, diammonium cerium(IV) nitrate, ammonium iron(III) sulfate, ammonium peroxodisulfate, iron(III) chloride, ammonium nitrate, t-butyl hydroperoxide, N-methylmorpholine N-oxide, and trimethylamine N-oxide. <5> The semiconductor substrate cleaning composition according to any one of <1> to <4>, wherein component (C) is at least one selected from the group consisting of vanadium(V) oxide, vanadate(V), salts of vanadate(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, diammonium cerium(IV) nitrate, ammonium iron(III) sulfate, ammonium peroxodisulfate, iron(III) chloride, ammonium nitrate, t-butyl hydroperoxide, N-methylmorpholine N-oxide, and trimethylamine N-oxide. <6> The semiconductor substrate cleaning composition according to any one of <1> to <4>, wherein component (C) is at least one selected from the group consisting of vanadium(V) oxide, vanadate(V), salts of vanadate(V), permanganic acid, salts of permanganic acid, iodic acid, salts of permanganic acid, iodic acid, salts of orthoperiodic acid, perchloric acid, salts of perchloric acid, diammonium cerium(IV) nitrate, ammonium iron(III) sulfate, ammonium peroxodisulfate <6> The semiconductor substrate cleaning composition according to any one of <1> to <5> above, which has a pH of 2 or less. <7> The semiconductor substrate cleaning composition according to any one of <1> to <6> above, 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 <1> to <7> above, which contains 0.5 to 10 mass % of component (A) based on the total amount of the semiconductor substrate cleaning composition.<9> The semiconductor substrate cleaning composition according to any one of <1> to <8> above, wherein the content of component (B) is 0.05 to 10 mass % based on the total amount of the semiconductor substrate cleaning composition. <10> The semiconductor substrate cleaning composition according to any one of <1> to <9> above, wherein the content of component (C) is 0.0005 to 1 mass % based on the total amount of the semiconductor substrate cleaning composition. <11> The semiconductor substrate cleaning composition according to any one of <1> to <10> above, wherein component (A) is at least one selected from the group consisting of acids having an anion represented by general formula (a) as a conjugate base and salts of acids having an anion represented by general formula (a) as a conjugate base, and the ratio [(A) / (B)] of the content (mol) of component (A) to the content (mol) of component (B) is 1 to 100. <12> The 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 30 Å / min or more, and the ratio of the titanium nitride removal rate to the molybdenum removal rate is 3 or more. <13> The 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 semiconductor substrate cleaning composition and stored at 60° C., titanium nitride can be removed at a removal rate of 30 Å / min or more, and the ratio of the titanium nitride removal rate to the low dielectric constant interlayer insulating film removal rate is 10 or more. <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. <15> A method for cleaning a semiconductor substrate, comprising contacting a substrate having titanium nitride, molybdenum, and a low-dielectric-constant interlayer insulating film with the semiconductor substrate cleaning composition according to any one of <1> to <14>. <16> A method for producing a semiconductor substrate, comprising a step of contacting a substrate having titanium nitride, molybdenum, and a low-dielectric-constant interlayer insulating film with the semiconductor substrate cleaning composition according to any one of <1> to <14>.

[0009] 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. That is, by using the semiconductor substrate cleaning composition of the present invention, titanium nitride can be removed while suppressing corrosion of molybdenum, for which the corrosion inhibitor is particularly ineffective. Therefore, it becomes possible to clean and manufacture semiconductor substrates with finer metal wiring, and to achieve higher integration of semiconductor elements.

[0010] The present invention relates to a compound comprising: component (A): at least one selected from the group consisting of hydrofluoric acid, salts of hydrofluoric acid, acids having an anion represented by the following general formula (a) as a conjugate base, and salts of acids having an anion represented by the following general formula (a) as a conjugate base; [MF n ] (n-k)- (a) Component (B): a compound represented by the following general formula (b): [MO m (OR) k-2m ] x (b) (In formulas (a) and (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 a fluoride ion with respect to M.) A semiconductor substrate cleaning composition comprising a component (C): an oxidizing agent, and a component (D): water, wherein α, represented by the following formula (I), is 0.2 or more and 1.1 or less; a cleaning method using the semiconductor substrate cleaning composition; and a method for producing a semiconductor substrate. (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.)

[0011] [Semiconductor substrate cleaning composition] The semiconductor substrate cleaning composition of the present invention comprises: Component (A): at least one selected from the group consisting of hydrofluoric acid, salts of hydrofluoric acid, acids having an anion represented by the following general formula (a) as a conjugate base, and salts of acids having an anion represented by the following general formula (a) as a conjugate base; [MF n ] (n-k)- (a) Component (B): a compound represented by the following general formula (b): [MO m (OR) k-2m ] x (b) (In formulas (a) and (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 or more and k / 2 or less, 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 a fluoride ion with respect to M.) The composition contains component (C): an oxidizing agent, and component (D): water, and 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.)

[0012] The semiconductor substrate cleaning composition of the present invention contains the above components, and by having the specific value of α, it can selectively remove titanium nitride from semiconductor substrates having titanium nitride, molybdenum, and a low-dielectric-constant interlayer insulating film. The reason for such excellent properties is unclear, but it is thought to be as follows: Fluoride ions, which are ions constituting component (A), are necessary for removing titanium nitride, but at the same time, they corrode molybdenum and the low-dielectric-constant interlayer insulating film. By including component (B), a compound having a specific element as its central element, in a manner that satisfies the specific value of α, the nucleophilicity of the fluorine compound is appropriately reduced, thereby removing titanium nitride while suppressing corrosion of molybdenum and other elements. The semiconductor substrate cleaning composition of the present invention will be described in detail below.

[0013] <Component (A)> The semiconductor substrate cleaning composition of the present invention contains component (A), which is at least one selected from the group consisting of hydrofluoric acid, salts of hydrofluoric acid, acids having an anion represented by the following general formula (a) as a conjugate base, and salts of acids having an anion represented by the following general formula (a) as a conjugate base: [MF n ] (n-k)- (a) (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 a fluoride ion with respect to M.) In other words, component (A) is at least one selected from the group consisting of hydrofluoric acid, salts of hydrofluoric acid, acids having an anion represented by general formula (a) as a conjugate base, and salts of acids having an anion represented by general formula (a) as a conjugate base. Component (A) releases fluoride ions during cleaning and plays a role in assisting in the removal of titanium nitride. Among these, at least one selected from the group consisting of hydrofluoric acid and acids having an anion represented by general formula (a) as a conjugate base is preferred, and an acid having an anion represented by general formula (a) as a conjugate base is more preferred.

[0014] Examples of the salt of hydrofluoric acid include sodium fluoride, potassium fluoride, ammonium fluoride, sodium acid fluoride, potassium acid fluoride, and ammonium acid fluoride.

[0015] In formula (a), which represents the anion constituting an acid or a salt thereof having the anion represented by 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. Furthermore, k is the oxidation number of M, and varies depending on M. Generally, it is 3 for boron, 4 for silicon, 4 for zirconium, 5 for phosphorus, and 4 for titanium. n is the coordination number of the fluoride ion to M, and varies depending on M. Generally, it is 4 for boron, 6 for silicon, 6 for zirconium, 6 for phosphorus, and 6 for titanium.

[0016] Examples of acids 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.

[0017] Examples of salts of acids having the anion represented by the general formula (a) as a conjugate base include salts of hexafluorosilicic acid, salts of tetrafluoroboric acid, salts of hexafluorozirconic acid, salts of hexafluoroantimonic acid, salts of hexafluoroniobic acid, salts of hexafluoroaluminic acid, salts of hexafluorotitanic acid, and salts of hexafluorophosphate. Examples of cations constituting the salts include sodium ions, potassium ions, and ammonium ions. In other words, examples of salts of acids having the anion represented by the general formula (a) as a conjugate base include salts in which the hydrogen ions of each acid are replaced with the cations. A specific example of the salt is ammonium hexafluorophosphate.

[0018] From the viewpoint of achieving both removal of titanium nitride and corrosion inhibition of molybdenum and the low dielectric constant interlayer insulating film, component (A) preferably 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, more preferably contains at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, tetrafluoroboric acid, hexafluorozirconic acid, hexafluorotitanic acid, and hexafluorophosphoric acid, even more preferably contains at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, and tetrafluoroboric acid, and still more preferably contains at least one selected from the group consisting of hexafluorosilicic acid and tetrafluoroboric acid. Furthermore, as a preferred embodiment, the acid 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, even more preferably at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, and tetrafluoroboric acid, and still more preferably at least one selected from the group consisting of hexafluorosilicic acid and tetrafluoroboric acid.

[0019] The semiconductor substrate cleaning composition of the present invention may contain only one kind of component (A), or may contain two or more kinds of components (A). For example, it may contain both hydrofluoric acid and an acid having the anion represented by the general formula (a) as a conjugate base, or it may contain two or more kinds of acids having the anion represented by the general formula (a) as a conjugate base.

[0020] The content of component (A) in the semiconductor substrate cleaning composition of the present invention is preferably 0.5 to 10 mass %, more preferably 1.0 to 8.0 mass %, even more preferably 2.0 to 7.0 mass %, and still more preferably 3.0 to 6.0 mass %, based on the total amount of the semiconductor substrate cleaning composition. When the content of component (A) is within the above range, titanium nitride can be removed while corrosion of molybdenum and low-dielectric-constant interlayer insulating film is suppressed.

[0021] <Component (B)> The semiconductor substrate cleaning composition of the present invention contains component (B), which is a compound represented by the following general formula (b): [MO m (OR) k-2m ] x (b) (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 of 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.) It is believed that component (B) moderately reduces the nucleophilicity of component (A), thereby achieving both the removal of titanium nitride and the inhibition of corrosion of molybdenum and the low dielectric constant interlayer insulating film.

[0022] 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. Furthermore, k is the oxidation number of M, and varies depending on M. Generally, boron is 3, silicon is 4, zirconium is 4, phosphorus is 5, and titanium is 4. R is one element selected from the group consisting of a hydrogen atom, an alkali metal, and an alkyl group. That is, when R is a hydrogen atom, component (B) is a compound having a hydroxyl group; when R is an alkali metal, component (B) is a salt of an acid with M as the central metal; and when R is an alkyl group, component (B) is an alkoxide. m is an integer of 0 to k / 2. When m is k / 2, component (B) is an oxide of M. x is a positive integer, and when x is 1, component (B) is a compound having one M in the molecule, and when x is 2 or more, component (B) is a polymer in which multiple compounds having one M in the molecule are bonded together. When x is 2 or more, component (B) preferably has a cyclic structure.

[0023] From the viewpoint of achieving both removal of titanium nitride and corrosion inhibition of molybdenum and low dielectric constant interlayer insulating film, component (B) preferably contains at least one selected from the group consisting of boric acid, salts of boric acid, silicon dioxide, silicic acid, salts of silicic acid, orthosilicic acid, salts of orthosilicic acid, alkoxysilane, zirconium oxide, zirconic acid, and salts of zirconic acid, more preferably contains at least one selected from the group consisting of boric acid, silicon dioxide, silicic acid, and salts of silicic acid, even more preferably contains at least one selected from the group consisting of boric acid, silicon dioxide, and salts of silicic acid, and still more preferably contains at least one selected from the group consisting of boric acid and salts of silicic acid. Furthermore, as a preferred embodiment, component (B) is preferably at least one selected from the group consisting of boric acid, salts of boric acid, silicon dioxide, silicic acid, salts of silicic acid, orthosilicic acid, salts of orthosilicic acid, alkoxysilane, zirconium oxide, zirconic acid, and salts of zirconic acid, more preferably at least one selected from the group consisting of boric acid, silicon dioxide, silicic acid, and salts of silicic acid, even more preferably at least one selected from the group consisting of boric acid, silicon dioxide, and salts of silicic acid, and still more preferably at least one selected from the group consisting of boric acid and salts of silicic acid.

[0024] Examples of the cations constituting the salts include sodium ions, potassium ions, and ammonium ions. That is, examples of boric acid salts, silicic acid salts, orthosilicic acid salts, and zirconic acid salts include salts in which the hydrogen ions of each acid are replaced with the cations. Specific examples of the salts include sodium metasilicate and potassium silicate. The semiconductor substrate cleaning composition of the present invention may contain only one type of component (B), or may contain two or more types.

[0025] The content of component (B) in the semiconductor substrate cleaning composition of the present invention is preferably 0.05 to 10 mass %, more preferably 0.1 to 5.0 mass %, even more preferably 0.2 to 4.0 mass %, and still more preferably 0.3 to 2.0 mass %, based on the total amount of the semiconductor substrate cleaning composition. When the content of component (B) is within the above range, titanium nitride can be removed while corrosion of molybdenum and low-dielectric-constant interlayer insulating film is suppressed.

[0026] <Component (C): Oxidizing Agent> The semiconductor substrate cleaning composition of the present invention contains component (C) as an oxidizing agent. Component (C) is contained in the composition to efficiently remove titanium nitride.

[0027] Component (C) can be any commonly known oxidizing agent, and from the viewpoint of simultaneously achieving both the removal of titanium nitride and the corrosion inhibition of molybdenum and the low dielectric constant interlayer insulating film, component (C) is preferably at least one selected from the group consisting of vanadium(V) oxide, vanadate(V), salts of vanadate(V), permanganic acid, salts of permanganate, iodic acid, salts of iodic acid, orthoperiodic acid, salts of orthoperiodic acid, perchloric acid, salts of perchloric acid, diammonium cerium(IV) nitrate, ammonium iron(III) sulfate, ammonium peroxodisulfate, iron(III) chloride, ammonium nitrate, t-butyl hydroperoxide, N-methylmorpholine N-oxide, and trimethylamine N-oxide. More preferably, it is at least one selected from the group consisting of vanadium(V) oxide, salts of permanganate, iodic acid, salts of iodic acid, perchloric acid, salts of perchloric acid, diammonium cerium(IV) nitrate, ammonium iron(III) sulfate, ammonium peroxodisulfate, ammonium nitrate, and N-methylmorpholine N-oxide, even more preferably, it is at least one selected from the group consisting of vanadium(V) oxide, salts of permanganate, and iodic acid, even more preferably, it is at least one selected from the group consisting of vanadium(V) oxide and salts of permanganate, and even more preferably, it is a salt of permanganate.

[0028] Examples of the cations constituting the salts include sodium ions, potassium ions, and ammonium ions. That is, examples of salts of vanadate (V), permanganate, iodic acid, orthoperiodic acid, and perchloric acid include salts in which the hydrogen ions of the respective acids are replaced with the cations. An example of a specific salt is potassium permanganate. The semiconductor substrate cleaning composition of the present invention may contain only one type of component (C), or may contain two or more types.

[0029] The content of component (C) in the semiconductor substrate cleaning composition of the present invention is preferably 0.0005 to 1 mass %, more preferably 0.0008 to 0.2 mass %, even more preferably 0.0010 to 0.1 mass %, still more preferably 0.0010 to 0.03 mass %, and still more preferably 0.0015 to 0.01 mass %, based on the total amount of the semiconductor substrate cleaning composition. When the content of component (C) is within the above range, titanium nitride can be removed while corrosion of molybdenum and low-dielectric-constant interlayer insulating film is suppressed.

[0030] Since the objective of the semiconductor substrate cleaning composition of the present invention is to suppress corrosion of molybdenum and low-dielectric-constant interlayer insulating films during cleaning, it is preferable to avoid the use of oxidizing agents with strong oxidizing power as much as possible, and even if they are used, it is preferable to keep the amount to an extremely small amount. The semiconductor substrate cleaning composition of the present invention is preferably substantially free of hydrogen peroxide, p-benzoquinone, copper(II) nitrate, sodium peroxoborate, bromic acid, or a salt of bromic acid. "Substantially free" means that the content is not more than an amount that does not impair the effects of the semiconductor substrate cleaning composition of the present invention. When hydrogen peroxide, p-benzoquinone, copper(II) nitrate, sodium perborate, bromic acid or a salt of bromic acid is contained, the total content thereof is preferably less than 0.0015 mass%, more preferably less than 0.0010 mass%, even more preferably less than 0.0008 mass%, and still more preferably less than 0.0005 mass%, based on the total amount of the semiconductor substrate cleaning composition, and it is even more preferable that the composition does not contain hydrogen peroxide, p-benzoquinone, copper(II) nitrate, sodium perborate, bromic acid or a salt of bromic acid.

[0031] <Component (D): Water> The semiconductor substrate cleaning composition of the present invention contains water as component (D). 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, various adsorption treatments, or the like. Pure water is more preferred, and ultrapure water is particularly preferred. The water content is the remainder after excluding components (A), (B), (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, based on 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 exhibited and the composition is more economical.

[0032] <Characteristics of the semiconductor substrate cleaning composition> The semiconductor substrate cleaning composition of the present invention contains the components (A), (B), (C), and (D) described above, and 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.)

[0033] Here, α is the value represented by formula (I) above, and is a value representing the ratio of the fluoride ions contained in component (A) to the element represented by M contained in components (A) and (B). When α is in the range of 0.2 or more and 1.1 or less, the elements contained in component (B) form fluoro complexes (fluorine-coordinated ate complexes) with the fluoride ions contained in component (A), and the fluoride ions are gradually supplied through an equilibrium reaction, which is thought to moderately reduce the nucleophilicity of the fluorine compound, thereby suppressing corrosion of molybdenum and the like while removing titanium nitride. α is 0.2 or more, preferably 0.4 or more, more preferably 0.7 or more, and 1.1 or less, preferably 1.05 or less, more preferably 1.0 or less. When α is in the above range, titanium nitride can be removed while suppressing corrosion of molybdenum and the low-dielectric-constant interlayer insulating film.

[0034] In formula (I), α is determined 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]). 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. When multiple elements M are used in component (A) and component (B), α is determined 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 with respect to each M (n(M)) and the molar concentration of each M in the composition. For example, when M consists of two types of M, M1 and M2, the denominator on the right side of the formula (I) is (n1(M1) × [M1] + n2(M2) × [M2]), where [M1] is the molar concentration of M1 in the composition, n1(M1) is the coordination number of fluoride ions for M1, [M2] is the molar concentration of M2 in the composition, and n2(M2) is the coordination number of fluoride ions for M2.

[0035] When component (A) is at least one selected from the group consisting of acids having an anion represented by the general formula (a) above as a conjugate base and salts of acids having an anion represented by the following general formula (a) as a conjugate base, the ratio of the content (moles) of component (A) to the content (moles) of component (B) [(A) / (B)] is preferably 1 to 100, more preferably 2 to 50, even more preferably 4 to 40, still more preferably 4 to 20, and even more preferably 8 to 20. When the ratio of the molar content of component (A) to the molar content of component (B) is within the above range, titanium nitride can be removed while suppressing corrosion of molybdenum and the low-dielectric-constant interlayer insulating film. The "ratio of the content (moles) of component (A) to the content (moles) of component (B)" refers to the "ratio [(A) / (B)] of the content (moles) of component (A) to the content (moles) of component (B)." In addition, when x in formula (b) representing the compound of component (B) exceeds 1, the "content (mol) of component (B)" when calculating the ratio is the amount obtained by multiplying the actual content of component (B) contained in the composition for cleaning semiconductor substrates by x.

[0036] The pH of the semiconductor substrate cleaning composition of the present invention is preferably 2 or less, more preferably 1.5 or less, even more preferably 1.0 or less, and even more preferably 0.5 or less. By having the pH in the above range, corrosion of molybdenum in particular can be suppressed. The pH can be measured by the method described in the Examples.

[0037] As described above, the semiconductor substrate cleaning composition of the present invention is used for removing 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 used for removing titanium nitride from a semiconductor substrate having titanium nitride, molybdenum, and a low-dielectric-constant interlayer insulating film. More specifically, the semiconductor substrate cleaning composition of the present invention is a semiconductor substrate cleaning composition used for removing titanium nitride from a semiconductor substrate having titanium nitride, molybdenum, and a low-dielectric-constant interlayer insulating film, comprising: Component (A): at least one selected from the group consisting of hydrofluoric acid, salts of hydrofluoric acid, acids having an anion represented by the following general formula (a) as a conjugate base, and salts of acids having an anion represented by the following general formula (a) as a conjugate base, [MF n ] (n-k)- (a) Component (B): a compound represented by the following general formula (b): [MO m (OR) k-2m ] x (b) (In formulas (a) and (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 a fluoride ion with respect to M.) A composition for cleaning semiconductor substrates comprising: component (C): an oxidizing agent; and component (D): water, wherein α, as 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.)

[0038] The semiconductor substrate cleaning composition of the present invention preferably removes titanium nitride at a removal rate of 30 Å / min or more when a substrate containing molybdenum and titanium nitride is immersed in the 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. The semiconductor substrate cleaning composition of the present invention has the above-described properties, allowing it to selectively remove titanium nitride from a semiconductor substrate containing molybdenum. In other words, by using the semiconductor substrate cleaning composition of the present invention, titanium nitride can be removed while suppressing corrosion of molybdenum, for which the corrosion inhibitor is particularly ineffective. This makes it possible to clean and manufacture semiconductor substrates with fine metal wiring, thereby enabling the high integration of semiconductor devices. The titanium nitride removal rate under the above conditions is preferably 30 Å / min or more, more preferably 100 Å / min or more, and even more preferably 150 Å / min or more. A higher titanium nitride removal rate under the above conditions is preferable because titanium nitride can be removed more efficiently, but is typically 2000 Å / min or less. The molybdenum removal rate under the above conditions is preferably 50 Å / min or less, more preferably 30 Å / min or less, and even more preferably 25 Å / min or less. The lower the molybdenum removal rate under the above conditions, the more effectively molybdenum corrosion can be suppressed, which is preferable, but it is usually 0.1 Å / min or more. The ratio of the titanium nitride removal rate to the molybdenum removal rate under the above conditions is preferably 3 or more, more preferably 5 or more, and even more preferably 8 or more. The higher the ratio of the titanium nitride removal rate to the molybdenum removal rate under the above conditions, the more effectively titanium nitride can be selectively removed from a semiconductor substrate containing molybdenum, which is preferable, but it is usually 300 or less. Specific measurement methods and conditions are described in "(2) Etching Rate (ER)" in the Examples.

[0039] The semiconductor substrate cleaning composition of the present invention preferably removes titanium nitride at a removal rate of 30 Å / min or more 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, and the ratio of the titanium nitride removal rate to the low-dielectric-constant interlayer insulating film removal rate is 10 or more. The semiconductor substrate cleaning composition of the present invention has the above-mentioned properties, making it possible to selectively remove titanium nitride from semiconductor substrates having low-dielectric-constant interlayer insulating films. This makes it possible to clean and manufacture semiconductor substrates with fine metal wiring, thereby enabling high integration of semiconductor devices. The titanium nitride removal rate under the above conditions is preferably 30 Å / min or more, more preferably 100 Å / min or more, and even more preferably 150 Å / min or more. A higher titanium nitride removal rate under the above conditions is preferable because titanium nitride can be removed more efficiently, but is usually 2000 Å / min or less. The removal rate of the low-dielectric-constant interlayer insulating film under the above conditions is preferably 15 Å / min or less, more preferably 10 Å / min or less, and even more preferably 6 Å / min 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 a semiconductor substrate having a low-dielectric-constant interlayer insulating film, which is preferable, but is usually 0.1 Å / min or more. The ratio of the removal rate of titanium nitride to the removal rate of the low-dielectric-constant interlayer insulating film under the above conditions is preferably 10 or more, more preferably 30 or more, and even more preferably 90 or more. The higher the ratio of the removal rate of titanium nitride to the removal rate of the low-dielectric-constant interlayer insulating film under the above conditions, the more selectively titanium nitride can be removed from a semiconductor substrate having a low-dielectric-constant interlayer insulating film, which is preferable, but is usually 500 or less. Specific measurement methods and conditions are described in "(2) Etching Rate (ER)" in the Examples. The low-dielectric-constant interlayer insulating film is preferably a film made of a silicon compound, more preferably a TEOS film, a silicon dioxide film, or a silicon-containing organic polymer film, even more preferably a TEOS film or a silicon dioxide film, and even more preferably a TEOS film. The silicon dioxide film is preferably a carbon-doped silicon dioxide film. Of the TEOS films, a PE-TEOS film (plasma TEOS film) is preferred.

[0040] [Method for cleaning a semiconductor substrate] The method for cleaning a semiconductor substrate of the present invention is a method for cleaning a semiconductor substrate, which comprises contacting the semiconductor substrate cleaning composition with a substrate having titanium nitride, molybdenum, and a low dielectric constant interlayer insulating film. That is, the method for cleaning a semiconductor substrate of the present invention comprises: Component (A): at least one selected from the group consisting of hydrofluoric acid, salts of hydrofluoric acid, acids having an anion represented by the following general formula (a) as a conjugate base, and salts of acids having an anion represented by the following general formula (a) as a conjugate base; [MF n ] (n-k)- (a) Component (B): a compound represented by the following general formula (b): [MO m (OR) k-2m ] x (b) (In formulas (a) and (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 a fluoride ion with M.) A method for cleaning a semiconductor substrate, comprising contacting a substrate having titanium nitride, molybdenum, and a low-dielectric-constant interlayer insulating film with a composition for cleaning a semiconductor substrate, the composition comprising: component (C): an oxidizing agent; and component (D): water, wherein α, represented by the following formula (I), is 0.2 to 1.1: (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.)

[0041] The cleaning method 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. By cleaning the semiconductor substrate using the cleaning method of the present invention, titanium nitride can be selectively removed from the semiconductor substrate having titanium nitride, molybdenum, and a low-dielectric-constant interlayer insulating film. In other words, by cleaning the substrate using the cleaning method of the present invention, titanium nitride can be removed while suppressing corrosion of molybdenum, which is particularly susceptible to corrosion inhibitors. This makes it possible to clean and manufacture semiconductor substrates with finer metal wiring, enabling higher integration of semiconductor devices.

[0042] The temperature during cleaning in the cleaning method of the present invention is not particularly limited, but is preferably 20 to 80°C, more preferably 25 to 70°C. Ultrasonic waves may also be used during cleaning. The cleaning time in the cleaning method of the present invention is not particularly limited, but is preferably 0.3 to 20 minutes, more preferably 0.5 to 10 minutes. In the cleaning method of the present invention, it is preferable to further rinse with a rinse solution containing water, alcohol, or the like after cleaning.

[0043] In the cleaning method of the present invention, the method of bringing the semiconductor substrate cleaning composition of the present invention into contact with the substrate is not particularly limited. For example, the semiconductor substrate cleaning composition of the present invention can be brought into contact with the substrate by dropping (single wafer spin treatment) or spraying (atomization treatment), or a method of immersing the substrate in the semiconductor substrate cleaning composition of the present invention can be used. In the present invention, either method can be used, and the method of immersing the substrate in the semiconductor substrate cleaning composition of the present invention is preferred.

[0044] [Method for producing a semiconductor substrate] The method for producing a semiconductor substrate of the present invention is a method for producing a semiconductor substrate, comprising a step of contacting the semiconductor substrate cleaning composition with a substrate having titanium nitride, molybdenum, and a low dielectric constant interlayer insulating film. That is, the method for producing a semiconductor substrate of the present invention comprises: Component (A): at least one selected from the group consisting of hydrofluoric acid, salts of hydrofluoric acid, acids having an anion represented by the following general formula (a) as a conjugate base, and salts of acids having an anion represented by the following general formula (a) as a conjugate base, [MFn ] (n-k)- (a) Component (B): a compound represented by the following general formula (b): [MO m (OR) k-2m ] x (b) (In formulas (a) and (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 a fluoride ion with M.) A method for producing a semiconductor substrate, comprising the step of contacting a substrate having titanium nitride, molybdenum, and a low-dielectric-constant interlayer insulating film with a composition for cleaning a semiconductor substrate, the composition comprising: a component (C): an oxidizing agent; and a component (D): water, wherein α, represented by the following formula (I), is 0.2 to 1.1: (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.) A specific method for producing a semiconductor substrate is shown below.

[0045] First, a barrier insulating film, a low-dielectric-constant interlayer insulating film, a hard mask, and a photoresist are laminated on a substrate such as silicon having a barrier metal, metal wiring, a low-dielectric-constant interlayer insulating film, and optionally a cap metal. The photoresist is then subjected to selective exposure and development to form a photoresist pattern. This photoresist pattern is then transferred onto the hard mask by dry etching. The photoresist pattern is then removed, and the low-dielectric-constant interlayer insulating film and the barrier insulating film are subjected to dry etching using the hard mask as an etching mask. The process of contacting the substrate with the semiconductor substrate cleaning composition is then carried out, resulting in a semiconductor substrate having a desired metal wiring pattern.

[0046] Here, silicon, amorphous silicon, polysilicon, glass, etc. are used as substrate materials. Tantalum, tantalum nitride, ruthenium, manganese, magnesium, cobalt, and oxides thereof are used as barrier metals. As described above, the low-dielectric-constant interlayer insulating film is preferably a film made of a silicon compound, more preferably a TEOS film, a silicon dioxide film, or a silicon-containing organic polymer film, even more preferably a TEOS film or a silicon dioxide film, and even more preferably a TEOS film. The silicon dioxide film is preferably a carbon-doped silicon dioxide film. Among TEOS films, a PE-TEOS film (plasma TEOS film) is preferred. The barrier insulating film is preferably silicon nitride, silicon carbide, silicon carbide nitride, etc. Titanium, titanium nitride, etc. are used as hard masks, and in the present invention, the hard mask contains titanium nitride. The metal wiring contains molybdenum. The metal wiring may be made of molybdenum alone or a molybdenum alloy, but is preferably made of molybdenum alone.

[0047] The step of contacting a substrate having titanium nitride, molybdenum, and a low dielectric constant interlayer insulating film with a semiconductor substrate cleaning composition, which is included in the present production method, is preferably carried out under the same conditions as those of the cleaning method described in the above section [Method for cleaning semiconductor substrate].

[0048] The method for producing a semiconductor substrate of the present invention includes a step of removing unnecessary components while leaving necessary components using the semiconductor substrate cleaning composition, which makes it possible to produce a semiconductor substrate with fine metal wiring and enables high integration of semiconductor elements.

[0049] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0050] <Analysis and Evaluation Methods> (1) pH The pH of the semiconductor substrate cleaning composition was measured by the glass electrode method (HORIBA: F-55S benchtop pH meter, HORIBA: Standard Tou pH electrode 9165S-10D, temperature: 25° C.).

[0051] (2) Etching Rate (ER) (2-1) Etching Rate (ER) of Titanium Nitride and Low-Dielectric-Constant Interlayer Insulating Film A "titanium nitride film-coated wafer" having a titanium nitride layer on a silicon wafer, and a "TEOS film-coated wafer" having a plasma TEOS (PE-TEOS) layer, a type of low-dielectric-constant interlayer insulating film, on a silicon wafer were prepared. Next, film thickness was measured. The film thickness of the titanium nitride layer of the "titanium nitride film-coated wafer" was measured using a fluorescent X-ray analyzer SEA1200VX (manufactured by SII NanoTechnology Inc.). The film thickness of the PE-TEOS layer of the "TEOS film-coated wafer" was measured using an optical film thickness meter n&k1280 (manufactured by n&k Technology Co., Ltd.). Next, the semiconductor substrate cleaning compositions of the Examples and Comparative Examples were adjusted to 60°C, and each film-coated wafer was immersed for 1 to 5 minutes, then rinsed with ultrapure water at 25°C, and the film thickness of each wafer was measured again using the above measurement method. The etching rate (ER) (Å / min) of each material was calculated by dividing the difference in film thickness before and after immersion in the semiconductor substrate cleaning composition by the treatment time. In Table 1, titanium nitride is represented as "TiN" and low-dielectric-constant interlayer insulating film is represented as "TEOS." (2-2) Measurement of Molybdenum Etching Rate (ER) A "molybdenum-filmed wafer" having a PVD-deposited molybdenum layer on a silicon wafer was prepared. The semiconductor substrate cleaning compositions of the Examples and Comparative Examples were adjusted to 60°C, and the molybdenum-filmed wafer was immersed for 1 to 5 minutes. The cleaning solution after immersion (referred to as "composition used" in the formula below) was diluted 10 to 30 times with 1% by mass of aqueous ammonia, and the molybdenum concentration was measured using an inductively coupled plasma optical emission spectrometer iCAP DUO-6300 (manufactured by Thermo Fisher Scientific). The molybdenum concentration (Mo concentration) before dilution was calculated and substituted into the following formula to calculate the etching rate (ER) (Å / min). This is shown as "Mo" in Table 1. 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.

[0052] (3) Etching Selectivity The etching rate ratio was calculated from the etching rates obtained by the above method, and this was used to evaluate the etching selectivity. The calculated etching rate ratios are as follows. (3-1) Etching Rate Ratio of Titanium Nitride to Molybdenum (TiN / Mo) In each Example and Comparative Example, the etching rate of titanium nitride (TiN) was divided by the etching rate of molybdenum (Mo) to calculate the etching rate ratio of titanium nitride to molybdenum (TiN / Mo). The larger this value, the more the semiconductor substrate cleaning composition can remove titanium nitride while suppressing corrosion of molybdenum. In other words, the larger this value, the more the semiconductor substrate cleaning composition can selectively remove titanium nitride from a semiconductor substrate containing molybdenum. (3-2) Etching Rate Ratio of Titanium Nitride to Low-Dielectric-Constant Interlayer Insulating Film (TiN / TEOS) In each Example and Comparative Example, the etching rate of titanium nitride (TiN) was divided by the etching rate of PE-TEOS (TEOS) to determine the etching rate ratio of titanium nitride to plasma TEOS, a type of low-dielectric-constant interlayer insulating film (TiN / TEOS). The larger this value, the more the semiconductor substrate cleaning composition can remove titanium nitride while suppressing corrosion of the low-dielectric-constant interlayer insulating film. In other words, the larger this 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.

[0053] <Semiconductor substrate cleaning composition> Example 1 Tetrafluoroboric acid (component (A)), boric acid (component (B)), potassium permanganate (component (C)), sulfuric acid, and ultrapure water (component (D)) were blended in the mass ratios shown in Table 1 to obtain a semiconductor substrate cleaning composition.

[0054] Examples 2 to 8 and Comparative Examples 1 to 7 Compositions for cleaning semiconductor substrates were obtained in the same manner as in Example 1, except that the components and mass ratios in Example 1 were changed to those shown in Table 1. Note that component (B) was not blended in Comparative Examples 4 to 7. Furthermore, sulfuric acid was not blended in Examples 5 to 8 and Comparative Examples 1, 3, and 5 to 7.

[0055] Each semiconductor substrate cleaning composition was analyzed and evaluated using the methods shown in the analytical and evaluation methods. The results of the analysis and evaluation of the semiconductor substrate cleaning compositions obtained in the examples and comparative examples are shown in Table 1. For convenience, in Table 1, component (A) is defined as a fluorine compound, component (B) as a silicon compound, etc., and the molar ratio of component (A) to component (B) [(A) / (B)] is also shown.

[0056]

[0057] As can be seen from Table 1, the semiconductor substrate cleaning compositions of the examples can selectively remove titanium nitride from semiconductor substrates having titanium nitride, molybdenum, and a low-dielectric-constant interlayer insulating film. Therefore, by using the semiconductor substrate cleaning composition of the present invention, it is possible to remove titanium nitride while suppressing corrosion of molybdenum, for which the effect of anticorrosives is particularly small. Therefore, the semiconductor substrate cleaning composition of the present invention is suitable for cleaning and manufacturing semiconductor substrates having fine metal wiring.

Claims

1. Component (A): at least one selected from the group consisting of hydrofluoric acid, salts of hydrofluoric acid, acids having an anion represented by the following general formula (a) as a conjugate base, and salts of acids having an anion represented by the following general formula (a) as a conjugate base: [MF] n ] (n-k)- (a) 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 a fluoride ion with respect to M.) Component (C): an oxidizing agent, and Component (D): water Including, A composition for cleaning semiconductor substrates, wherein α represented by the following formula (I) is 0.2 or more and 1.1 or less: [0010] (In formula (I), [F] is the molar concentration of fluoride ion in the composition, [M] is the molar concentration of M in the composition, and n(M) is the coordination number of fluoride ion with respect to M.)

2. 2. The semiconductor substrate cleaning composition according to claim 1, wherein the 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.

3. 3. The semiconductor substrate cleaning composition according to claim 1, wherein the component (B) comprises at least one member selected from the group consisting of boric acid, a salt of boric acid, silicon dioxide, silicic acid, a salt of silicic acid, orthosilicic acid, a salt of orthosilicic acid, an alkoxysilane, zirconium oxide, zirconic acid, and a salt of zirconic acid.

4. 3. The semiconductor substrate cleaning composition according to claim 1, wherein the component (C) is at least one member selected from the group consisting of vanadium(V) oxide, vanadate(V), salts of vanadate(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, diammonium cerium(IV) nitrate, ammonium iron(III) sulfate, ammonium peroxodisulfate, iron(III) chloride, ammonium nitrate, t-butyl hydroperoxide, N-methylmorpholine N-oxide, and trimethylamine N-oxide.

5. 3. The semiconductor substrate cleaning composition according to claim 1, which is substantially free of hydrogen peroxide, p-benzoquinone, copper (II) nitrate, sodium peroxoborate, bromic acid or a salt of bromic acid.

6. 3. The semiconductor substrate cleaning composition according to claim 1, wherein the pH of the semiconductor substrate cleaning composition is 2 or less.

7. 3. 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. 3. The semiconductor substrate cleaning composition according to claim 1, wherein the content of the component (A) is 0.5 to 10 mass % based on the total amount of the semiconductor substrate cleaning composition.

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

10. 3. The semiconductor substrate cleaning composition according to claim 1, wherein the content of the component (C) is 0.0005 to 1 mass % based on the total amount of the semiconductor substrate cleaning composition.

11. 3. The semiconductor substrate cleaning composition according to claim 1, wherein the 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 [(A) / (B)] of the content (mol) of the component (A) to the content (mol) of the component (B) is 1 to 100.

12. 3. The semiconductor substrate cleaning composition according to claim 1, wherein when a substrate having molybdenum and titanium nitride is immersed in the semiconductor substrate cleaning composition and stored at 60° C., the composition can remove titanium nitride at a removal rate of 30 Å / min or more, and the ratio of the removal rate of titanium nitride to the removal rate of molybdenum is 3 or more.

13. 3. The semiconductor substrate cleaning composition according to claim 1, 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., the titanium nitride can be removed at a removal rate of 30 Å / min or more, and the ratio of the removal rate of titanium nitride to the removal rate of the low dielectric constant interlayer insulating film is 10 or more.

14. 3. A method for cleaning a semiconductor substrate, comprising contacting a substrate having titanium nitride, molybdenum and a low dielectric constant interlayer insulating film with the semiconductor substrate cleaning composition according to claim 1 or 2.

15. 3. A method for producing a semiconductor substrate, comprising the step of contacting a substrate having titanium nitride, molybdenum and a low dielectric constant interlayer insulating film with the semiconductor substrate cleaning composition according to claim 1 or 2.

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