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

Abstract

The present invention is able to provide a composition for semiconductor substrate cleaning, the composition containing: a component (A) that is at least one substance which is selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid that has an anion represented by general formula (a) as a conjugate base, and a salt of the acid that has an anion represented by general formula (a) as a conjugate base; a component (B) that is a compound represented by general formula (b); a component (C) that is an oxidant; a component (D) that is a tungsten corrosion inhibitor; a component (E) that is an organic solvent; and a component (F) that is water. The component (E) contains at least one substance that is selected from the group consisting of tetrahydrofuran, acetone, and acetonitrile, and α represented by formula (I) is 0.2 to 1.1 inclusive.

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, concerns arise about the diffusion of metal atoms forming the wiring into semiconductor devices. In light of this situation, the use of tungsten, which has low atomic diffusion, for metal wiring has been considered. However, increasing the amount of tungsten corrosion inhibitor added to ensure sufficient tungsten corrosion protection while maintaining titanium nitride removability has led to the problem of precipitation of the tungsten corrosion inhibitor. On the other hand, reducing the amount of oxidizer used in the liquid composition disclosed in Patent Document 1 suppresses tungsten corrosion. However, the titanium nitride removal rate decreases. Increasing the amount of fluorine compound to compensate for this results in corrosion of low-dielectric-constant interlayer insulating films composed of silicon dioxide and the like. Thus, in the manufacture of semiconductor substrates using tungsten 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 tungsten 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, tungsten, 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 applicant conducted extensive research to solve the above problems and discovered that by adding a specific organic solvent to a semiconductor substrate cleaning composition, the amount of tungsten anticorrosive can be increased without causing precipitation of the tungsten anticorrosive, and sufficient tungsten anticorrosion can be ensured while maintaining titanium nitride removability, leading to the completion of the present invention. That is, 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 general 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 a member 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: component (C): an oxidizing agent; component (D): a tungsten corrosion inhibitor; component (E): an organic solvent; and component (F): water, wherein component (E) contains at least one member selected from the group consisting of tetrahydrofuran, acetone, and acetonitrile; 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.) <2> The semiconductor substrate cleaning composition according to the above <1>, wherein the component (A) contains at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, tetrafluoroboric acid, salts of hexafluorosilicic acid, and salts of tetrafluoroboric acid. <3> The semiconductor substrate cleaning composition according to the above <1> or <2>, wherein the component (B) contains at least one selected from the group consisting of boric acid, salts of boric acid, silicic acid, salts of silicic acid, orthosilicic acid, and salts of orthosilicic acid. <4> The semiconductor substrate cleaning composition according to any one of <1> to <3> above, wherein the component (C) comprises at least one selected from the group consisting of vanadium(V) oxide, vanadic acid(V), salts of vanadic acid(V), iodic acid, salts of iodic acid, orthoperiodic acid, and salts of orthoperiodic acid. <5> The semiconductor substrate cleaning composition according to any one of <1> to <4> above, wherein the component (D) comprises at least one selected from the group consisting of benzethonium chloride, benzalkonium chloride, alkylpyridinium chloride, and quaternary ammonium salts. <6> The semiconductor substrate cleaning composition according to any one of <1> to <5> above, which is used for removing titanium nitride from a semiconductor substrate having titanium nitride, tungsten, and a low-dielectric-constant interlayer insulating film. <7> The semiconductor substrate cleaning composition according to any one of <1> to <6> above, wherein the content of the component (A) is 0.1 to 10 mass % based on the total amount of the semiconductor substrate cleaning composition. <8> The semiconductor substrate cleaning composition according to any one of <1> to <7> above, wherein the content of the component (B) is 0.005 to 5 mass % 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 the component (C) is 0.0005 to 1 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 the component (D) 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 the above <1> to <10>, wherein the content of the component (E) is 0.1 to 50 mass % based on the total amount of the semiconductor substrate cleaning composition. <12> The semiconductor substrate cleaning composition according to any one of the above <1> to <11>, wherein the component (A) is at least one selected from the group consisting of acids having an anion represented by the above general formula (a) as a conjugate base and salts of acids having an anion represented by the above 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. <13> The semiconductor substrate cleaning composition according to any one of the above <1> to <12>, wherein, when a substrate having tungsten and titanium nitride is immersed in the semiconductor substrate cleaning composition and stored at 60°C, the composition removes titanium nitride at a removal rate of 80 Å / min or more and the removal rate of tungsten is 3 Å / min or less. <14> The semiconductor substrate cleaning composition according to any one of <1> to <12> above, 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 composition removes titanium nitride at a removal rate of 80 Å / min or more and the removal rate of the low-dielectric-constant interlayer insulating film is 3 Å / min or less. <15> A method for cleaning a semiconductor substrate, comprising contacting the semiconductor substrate cleaning composition according to any one of <1> to <14> above with a substrate having titanium nitride, tungsten, and a low-dielectric-constant interlayer insulating film. <16> A method for producing a semiconductor substrate, comprising contacting the semiconductor substrate cleaning composition according to any one of <1> to <14> above with a substrate having titanium nitride, tungsten, and a low-dielectric-constant interlayer insulating film.

[0009] The semiconductor substrate cleaning composition of the present invention can selectively remove titanium nitride from a semiconductor substrate having titanium nitride, tungsten, 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 particularly suppressing corrosion of tungsten. Therefore, it becomes possible to clean and manufacture semiconductor substrates with fine metal wiring, and high integration of semiconductor elements can be achieved.

[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 general 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; a component (D): a tungsten corrosion inhibitor; a component (E): an organic solvent; and a component (F): water, wherein the component (E) contains at least one selected from the group consisting of tetrahydrofuran, acetone, and acetonitrile; and α, represented by the following formula (I), is 0.2 to 1.1, 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 general 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 comprises component (C): an oxidizing agent, component (D): a tungsten corrosion inhibitor, component (E): an organic solvent, and component (F): water, wherein component (E) contains at least one selected from the group consisting of tetrahydrofuran, acetone, and acetonitrile, 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, tungsten, 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 tungsten 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 tungsten and the like. 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, boron is 3, silicon is 4, zirconium is 4, phosphorus is 5, and titanium is 4. n is the coordination number of the fluoride ion to M, and varies depending on M. Generally, boron is 4, silicon is 6, zirconium is 6, phosphorus is 6, and titanium is 6.

[0016] 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.

[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 tungsten 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 0.1 to 10 mass %, more preferably 0.3 to 8.0 mass %, even more preferably 0.5 to 6.0 mass %, and still more preferably 1.0 to 5.0 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 tungsten 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 tungsten 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 tungsten and the 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 0.005 to 5 mass %, more preferably 0.01 to 3.0 mass %, even more preferably 0.02 to 2.0 mass %, and still more preferably 0.03 to 1.0 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 tungsten 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 a commonly known oxidizing agent. Among them, from the viewpoint of simultaneously achieving the removal of titanium nitride and the corrosion inhibition of tungsten and the low dielectric constant interlayer insulating film, component (C) is preferably vanadium(V) oxide, vanadic acid(V), a salt of vanadic acid(V), permanganic acid, a salt of permanganic acid, iodic acid, a salt of iodic acid, orthoperiodic acid, a salt of orthoperiodic acid, perchloric acid, a salt of perchloric acid, diammonium cerium(IV) nitrate, ammonium iron(III) sulfate, ammonium peroxodisulfate, iron(III) chloride, ammonium nitrate, t-butyl hydroperoxide, N-methylmorpholine N-oxygen and trimethylamine N-oxide, more preferably at least one selected from the group consisting of vanadium(V) oxide, salts of permanganate, iodic acid, salts of iodic acid, periodic acid, perchloric acid, salts of perchloric acid, diammonium cerium(IV) nitrate, ammonium iron(III) sulfate, ammonium peroxodisulfate, ammonium nitrate, and N-methylmorpholine N-oxide, and even more preferably at least one selected from the group consisting of vanadium(V) oxide, iodic acid, and periodic acid.

[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, iodate, orthoperiodate, and perchlorate include salts in which the hydrogen ions of each acid 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 %, still more preferably 0.0010 to 0.1 mass %, still more preferably 0.0010 to 0.05 mass %, and particularly preferably 0.0015 to 0.03 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 tungsten 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 tungsten 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 peroxoborate, 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 composition for cleaning semiconductor substrates, and it is even more preferable that the composition does not contain hydrogen peroxide, p-benzoquinone, copper(II) nitrate, sodium peroxoborate, bromic acid or a salt of bromic acid.

[0031] <Component (D): Tungsten Corrosion Inhibitor> The semiconductor substrate cleaning composition of the present invention contains a tungsten corrosion inhibitor, component (D). The tungsten corrosion inhibitor used in the present invention is not particularly limited, and known tungsten corrosion inhibitors can be used. For example, alkylamines and their salts, fluoroalkylamines and their salts, alkylamine oxides, fluoroalkylamine oxides, alkyl betaines, fluoroalkyl betaines, alkyl quaternary ammoniums and their salts, fluoroalkyl quaternary ammoniums and their salts, alkyl pyridinium chloride, fluoroalkyl quaternary pyridinium salts, alkyl quaternary bipyridinium salts, fluoroalkyl quaternary bipyridinium salts, alkyl quaternary imidazolium salts, and fluoroalkyl quaternary imidazolium salts can be mentioned.

[0032] Specific examples of alkylamines and salts thereof or fluoroalkylamines and salts thereof include octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, dodecylamine hydrochloride, perfluorododecylamine, dioctylamine, didecylamine, didodecylamine, trioctylamine, tridecylamine, tridodecylamine, octyldimethylamine, decyldimethylamine, dodecyldimethylamine, etc. Among these, dodecylamine, tetradecylamine, and hexadecylamine are preferred.

[0033] Specific examples of alkylamine oxides or fluoroalkylamine oxides include N-decyl-N,N-dimethylamine oxide, N-dodecyl-N,N-dimethylamine oxide, N-tetradecyl-N,N-dimethylamine oxide, N-hexadecyl-N,N-dimethylamine oxide, Surflon S-241 (trade name, perfluoroalkylamine oxide manufactured by AGC Seimi Chemical Co., Ltd.), and Amogene (trade name, alkylamine oxide manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), of which Surflon S-241 is preferred.

[0034] Specific examples of alkyl betaines or fluoroalkyl betaines include dodecyl dimethyl amino acetic acid betaine, perfluoro dodecyl dimethyl amino acetic acid betaine, dodecyl dimethyl amino sulfobetaine, perfluoro dodecyl dimethyl amino sulfobetaine, and Amphitol (trade name, alkyl betaine manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), etc. Among these, Amphitol 20YB and Amphitol 24B are preferred.

[0035] Specific examples of alkyl quaternary ammonium and salts thereof or fluoroalkyl quaternary ammonium and salts thereof include dodecyltrimethylammonium hydroxide, tetradecyltrimethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, benzyldimethyldecylammonium hydroxide, benzyldimethyldodecylammonium hydroxide, benzyldimethyltetradecylammonium hydroxide, benzyldimethylhexadecylammonium hydroxide, dodecyltrimethylammonium hydroxide, tetradecyltrimethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, benzyldimethyldecylammonium chloride, benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, benzyldimethylhexadecylammonium chloride, benzalkonium chloride, benzethonium chloride, ESOCARD (trade name, polyoxyethylene-added quaternary ammonium chloride manufactured by Lion Corporation), and Fluorad. Examples include FC-135 (trade name, perfluoroalkyl quaternary ammonium iodide manufactured by Sumitomo 3M Co., Ltd.), QUATAMIN (trade name, alkyl quaternary ammonium chloride manufactured by Kao Corporation), and CATIOGEN (trade name, alkyl quaternary ammonium ethyl sulfate manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.). Among these, benzalkonium chloride, benzethonium chloride, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, and Fluorad FC-135 are preferred.

[0036] Specific examples of alkylpyridinium chloride or fluoroalkyl quaternary pyridinium salts include 1-decylpyridinium chloride, 1-dodecylpyridinium chloride, 1-tetradecylpyridinium chloride, 1-hexadecylpyridinium chloride, and 1-hexadecyl-4-methylpyridinium chloride, of which 1-dodecylpyridinium chloride and 1-hexadecyl-4-methylpyridinium chloride are preferred.

[0037] Specific examples of alkyl quaternary bipyridinium salts or fluoroalkyl quaternary bipyridinium salts include 1,1'-di-n-octyl-4,4'-bipyridinium dibromide, 1-methyl-1'-tetradecyl-4,4'-bipyridinium dibromide, and 1,1'-di-n-perfluorooctyl-4,4'-bipyridinium dibromide, of which 1,1'-di-n-octyl-4,4'-bipyridinium dibromide is preferred.

[0038] Specific examples of alkyl quaternary imidazolium salts or fluoroalkyl quaternary imidazolium salts include 1-octyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium chloride, 1-dodecyl-3-methylimidazolium chloride, 1-tetradecyl-3-methylimidazolium chloride, 1-hexadecyl-3-methylimidazolium chloride, 1-octadecyl-3-methylimidazolium chloride, 1,3-didecyl-2-methylimidazolium chloride, and 1-perfluorooctyliimidazolium chloride. Among these, 1-dodecyl-3-methylimidazolium chloride, 1-tetradecyl-3-methylimidazolium chloride, 1-hexadecyl-3-methylimidazolium chloride, 1-octadecyl-3-methylimidazolium chloride, and 1,3-didecyl-2-methylimidazolium chloride are preferred.

[0039] Other tungsten corrosion inhibitors include polyoxyalkylene alkylamines, polyoxyalkylene fluoroalkylamines, polyoxyalkylene alkyl ethers, polyoxyalkylene fluoroalkyl ethers, polyoxyalkylene alkyl phosphates, polyoxyalkylene fluoroalkyl phosphates, polyoxyalkylene alkyl ether sulfates, polyoxyalkylene fluoroalkyl ether sulfates, alkyl diphenyl ether sulfonates, and fluoroalkyl diphenyl ether sulfonates.

[0040] Specific examples of polyoxyalkylene alkylamines or polyoxyalkylene fluoroalkylamines include Nymeen (trade name, polyoxyethylene alkylamine manufactured by Nippon Oil & Fats Corporation) and Noigen (trade name, polyoxyethylene alkylamine manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), etc. Among these, Nymeen F-215, Noigen ET-189, and Noigen XL-140 are preferred.

[0041] Specific examples of polyoxyalkylene alkyl ethers or polyoxyalkylene fluoroalkyl ethers include Newcol (trade name, alkyl ether-type nonionic surfactant manufactured by Nippon Nyukazai Co., Ltd.), Ftergent (trade name, polyoxyethylene perfluoroalkyl ether manufactured by Neos Corporation), and Antifloss (trade name, special nonionic surfactant manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.). Of these, Newcol 2308-LY, Antifloss M-9, Ftergent 222F, Ftergent 250, and Ftergent 251 are preferred.

[0042] Specific examples of polyoxyalkylene alkyl phosphate esters or polyoxyalkylene fluoroalkyl phosphate esters include Phosphanol (trade name, polyethylene phosphate ester manufactured by Toho Chemical Industry Co., Ltd.), of which Phosphanol RA-600, Phosphanol RS-710, Phosphanol RL-310, Phosphanol ED-230, Phosphanol iD10-P, Phosphanol ML-240, and Phosphanol OF-100 are preferred.

[0043] Specific examples of polyoxyalkylene alkyl ether sulfates or polyoxyalkylene fluoroalkyl ether sulfates include Hitenol (trade name, polyoxyethylene alkyl ether sulfonic acid manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), of which Hitenol NF-08, Hitenol NF-13, and Hitenol NF-17 are preferred.

[0044] Specific examples of alkyldiphenylether sulfonates or fluoroalkyldiphenylether sulfonates include Pelex (trade name, alkyldiphenylether disulfonates manufactured by Kao Corporation). Of these, Pelex SS-H and Pelex SS-L are preferred.

[0045] In the present invention, it is preferable that component (D) contains at least one selected from the group consisting of benzethonium chloride, benzalkonium chloride, alkylpyridinium chloride, and quaternary ammonium salts.

[0046] The content of component (D) in the semiconductor substrate cleaning composition of the present invention is preferably 0.0005 to 1 mass%, more preferably 0.0008 to 0.8 mass%, even more preferably 0.0010 to 0.6 mass%, even more preferably 0.0012 to 0.5 mass%, and particularly preferably 0.0015 to 0.3 mass%, based on the total amount of the semiconductor substrate cleaning composition. By having the content of component (D) within the above range, sufficient tungsten corrosion inhibitor performance can be obtained. If the content of the tungsten corrosion inhibitor is less than 0.0005 mass%, sufficient corrosion inhibitor performance may not be obtained, while if it exceeds 1 mass%, it is not economical, not suitable for practical use, and precipitation may occur.

[0047] <Component (E): Organic Solvent> The semiconductor substrate cleaning composition of the present invention contains component (E), which is an organic solvent. In the present invention, component (E) includes at least one selected from the group consisting of tetrahydrofuran, acetone, and acetonitrile. By adding such a specific organic solvent, the amount of tungsten corrosion inhibitor can be increased without causing precipitation of the tungsten corrosion inhibitor, thereby ensuring sufficient tungsten corrosion protection while maintaining titanium nitride removability. The content of component (E) in the semiconductor substrate cleaning composition of the present invention is preferably 0.1 to 50 mass%, more preferably 0.5 to 20 mass%, even more preferably 1.0 to 15 mass%, and even more preferably 2.0 to 10 mass%, based on the total amount of the semiconductor substrate cleaning composition.

[0048] <Component (F): Water> The semiconductor substrate cleaning composition of the present invention contains water, component (F). 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) to (E) and other additives from the semiconductor substrate cleaning composition of the present invention, and is preferably 70 mass% or more, more preferably 80 to 95 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.

[0049] <Characteristics of the Semiconductor Substrate Cleaning Composition> The semiconductor substrate cleaning composition of the present invention contains the above-mentioned components (A) to (F), 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.)

[0050] 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 tungsten 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 tungsten and the low-dielectric-constant interlayer insulating film.

[0051] 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.

[0052] When component (A) is at least one selected from the group consisting of acids having an anion represented by the 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, 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 particularly 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 tungsten and the low-dielectric-constant interlayer insulating film. Note that when calculating the ratio, the "content (moles) of component (B)" refers to the actual content of component (B) contained in the semiconductor substrate cleaning composition multiplied by x when x in formula (b) representing the compound of component (B) exceeds 1.

[0053] The pH of the semiconductor substrate cleaning composition of the present invention is preferably not more than 2, more preferably not more than 1.5, even more preferably not more than 1.0, and even more preferably not more than 0.5. When the pH is in the above range, corrosion of tungsten in particular can be suppressed.

[0054] 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, tungsten, 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, tungsten, 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, tungsten, 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 a semiconductor substrate comprising: component (C): an oxidizing agent; component (D): a tungsten corrosion inhibitor; component (E): an organic solvent; and component (F): water, wherein component (E) contains at least one selected from the group consisting of tetrahydrofuran, acetone, and acetonitrile; 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.)

[0055] The semiconductor substrate cleaning composition of the present invention preferably removes titanium nitride at a removal rate of 80 Å / min or more and a tungsten removal rate of 3 Å / min or less when a substrate containing tungsten and titanium nitride is immersed in the semiconductor substrate cleaning composition and stored at 60°C. The semiconductor substrate cleaning composition of the present invention has the above-described properties, allowing selective removal of titanium nitride from a semiconductor substrate containing tungsten. In other words, by using the semiconductor substrate cleaning composition of the present invention, titanium nitride can be removed while particularly suppressing tungsten corrosion. This makes it possible to clean and manufacture semiconductor substrates with fine metal wiring, thereby enabling highly integrated semiconductor devices. The titanium nitride removal rate under the above conditions is preferably 80 Å / min or more, more preferably 120 Å / min or more, and even more preferably 160 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 500 Å / min or less. The tungsten removal rate under the above conditions is preferably 3 Å / min or less, more preferably 2 Å / min or less, and even more preferably 1 Å / min or less. The lower the tungsten removal rate under the above conditions, the more effectively tungsten 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 tungsten removal rate under the above conditions is preferably 25 or more, more preferably 50 or more, and even more preferably 100 or more. The higher the ratio of the titanium nitride removal rate to the tungsten removal rate under the above conditions, the more effectively titanium nitride can be selectively removed from a semiconductor substrate containing tungsten, which is preferable, but it is usually 5000 or less. Specific measurement methods and conditions are described in "(1) Etching Rate (ER)" in the Examples.

[0056] The semiconductor substrate cleaning composition of the present invention preferably removes titanium nitride at a removal rate of 80 Å / min or more and a removal rate of the low-dielectric-constant interlayer insulating film of 3 Å / min or less 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 semiconductor substrate cleaning composition of the present invention has the above-described properties, allowing for selective removal of titanium nitride from semiconductor substrates having a low-dielectric-constant interlayer insulating film. This makes it possible to clean and manufacture semiconductor substrates with finer metal wiring, thereby enabling higher integration of semiconductor devices. The titanium nitride removal rate under the above conditions is preferably 80 Å / min or more, more preferably 120 Å / min or more, and even more preferably 160 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 500 Å / min or less. The low-dielectric-constant interlayer insulating film removal rate under the above conditions is preferably 3 Å / min or less, more preferably 2 Å / min or less, and even more preferably 1 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, and the more preferable it is, but it is usually 0.1 Å / min or 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 is preferably 25 or higher, more preferably 50 or higher, and even more preferably 100 or higher. 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, and the more preferable it is, but it is usually 5000 or lower. Specific measurement methods and conditions are described in "(1) 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.

[0057] [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, tungsten, 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 general 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 a member 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, tungsten, and a low-dielectric-constant interlayer insulating film with a composition for cleaning a semiconductor substrate, the composition comprising: component (C): an oxidizing agent; component (D): a tungsten corrosion inhibitor; component (E): an organic solvent; and component (F): water, wherein component (E) comprises at least one selected from the group consisting of tetrahydrofuran, acetone, and acetonitrile, and 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.)

[0058] The cleaning method of the present invention is carried out to remove titanium nitride from a semiconductor substrate having titanium nitride, tungsten, 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, tungsten, 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 particularly suppressing corrosion of tungsten. As a result, it becomes possible to clean and manufacture semiconductor substrates with finer metal wiring, enabling higher integration of semiconductor devices.

[0059] 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.

[0060] 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.

[0061] [Method for manufacturing a semiconductor substrate] The method for manufacturing a semiconductor substrate of the present invention is a method for manufacturing a semiconductor substrate, comprising a step of contacting the semiconductor substrate cleaning composition with a substrate having titanium nitride, tungsten, and a low-dielectric-constant interlayer insulating film. That is, the method for manufacturing 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 general 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 a member 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: contacting a substrate having titanium nitride, tungsten, and a low-dielectric-constant interlayer insulating film with a composition for cleaning a semiconductor substrate, the composition comprising: component (C): an oxidizing agent; component (D): a tungsten corrosion inhibitor; component (E): an organic solvent; and component (F): water, wherein component (E) comprises at least one member selected from the group consisting of tetrahydrofuran, acetone, and acetonitrile; and 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.

[0062] 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.

[0063] 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 tungsten. The metal wiring may be tungsten alone or a tungsten alloy, but tungsten alone is preferred.

[0064] The step of contacting a substrate having titanium nitride, tungsten, 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].

[0065] 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.

[0066] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0067] <Analysis and Evaluation Methods> (1) Etching Rate (ER) (1-1) 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. Titanium nitride etching rate determination AA: 160 Å / min or more A: 120 Å / min or more but less than 160 Å / min B: 80 Å / min or more but less than 120 Å / min C: less than 80 Å / min TEOS etching rate determination AA: less than 1 Å / min A: 1 Å / min or more but less than 2 Å / min B: 2 Å / min or more but less than 3 Å / min C: 3 Å / min or more

[0068] (1-2) Tungsten Etching Rate (ER) A "tungsten-filmed wafer" having a PVD-deposited tungsten layer on a silicon wafer was prepared. Next, the semiconductor substrate cleaning compositions of the Examples and Comparative Examples were adjusted to 60°C, and the tungsten-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 mass% aqueous ammonia, and the tungsten concentration was measured using an inductively coupled plasma optical emission spectrometer iCAP DUO-6300 (manufactured by Thermo Fisher Scientific). The tungsten concentration (W concentration) before dilution was calculated and substituted into the formula below to calculate the tungsten etching rate (ER) (ER of W) (Å / min). In the formula below, "19.30 g / cm ３" is the density of tungsten, and "wafer area" is the area of ​​the tungsten film on the wafer. Determination of tungsten etching rate AA: Less than 1 Å / min A: 1 Å / min or more but less than 2 Å / min B: 2 Å / min or more but less than 3 Å / min C: 3 Å / min or more

[0069] (2) Evaluation of Precipitation Judgment of the Presence or Absence of Precipitation A: No Precipitation by Visual Observation C: Precipitation by Visual Observation

[0070] <Semiconductor substrate cleaning composition> (Example 1) Hexafluorosilicic acid (component (A)), potassium silicate (component (B)), periodic acid (component (C)), benzalkonium chloride (component (D)), tetrahydrofuran (component (E)), and water (ultrapure water) were blended to give the concentrations shown in Table 1 to obtain a semiconductor substrate cleaning composition.

[0071] (Examples 2 to 10 and Comparative Examples 1 to 6) Compositions for cleaning semiconductor substrates were obtained in the same manner as in Example 1, except that the components and concentrations in Example 1 were changed to those shown in Table 1. In Comparative Examples 2 to 6, component (E) was not added.

[0072] Each semiconductor substrate cleaning composition was analyzed and evaluated using the methods shown in the analytical and evaluation methods. The results of analysis and evaluation of the semiconductor substrate cleaning compositions obtained in Examples and Comparative Examples are shown in Table 1.

[0073]

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 general 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.) A composition for cleaning a semiconductor substrate, comprising: component (C): an oxidizing agent, component (D): a tungsten corrosion inhibitor, component (E): an organic solvent, and component (F): water, wherein component (E) contains at least one selected from the group consisting of tetrahydrofuran, acetone, and acetonitrile, 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 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. 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, salts of hexafluorosilicic acid, and salts of tetrafluoroboric acid.

3. The semiconductor substrate cleaning composition according to claim 1 or 2, wherein the component (B) comprises at least one member selected from the group consisting of boric acid, salts of boric acid, silicic acid, salts of silicic acid, orthosilicic acid, and salts of orthosilicic acid.

4. The semiconductor substrate cleaning composition according to any one of claims 1 to 3, wherein the component (C) comprises at least one member selected from the group consisting of vanadium (V) oxide, vanadic acid (V), salts of vanadic acid (V), iodic acid, salts of iodic acid, orthoperiodic acid, and salts of orthoperiodic acid.

5. The semiconductor substrate cleaning composition according to any one of claims 1 to 4, wherein the component (D) comprises at least one member selected from the group consisting of benzethonium chloride, benzalkonium chloride, alkylpyridinium chloride, and quaternary ammonium salts.

6. The semiconductor substrate cleaning composition according to any one of claims 1 to 5, which is used for removing titanium nitride from a semiconductor substrate having titanium nitride, tungsten and a low dielectric constant interlayer insulating film.

7. The semiconductor substrate cleaning composition according to any one of claims 1 to 6, wherein the content of said component (A) is 0.1 to 10 mass % based on the total amount of said semiconductor substrate cleaning composition.

8. The semiconductor substrate cleaning composition according to any one of claims 1 to 7, wherein the content of said component (B) is 0.005 to 5 mass % based on the total amount of said semiconductor substrate cleaning composition.

9. The semiconductor substrate cleaning composition according to any one of claims 1 to 8, wherein the content of said component (C) is 0.0005 to 1 mass % based on the total amount of said semiconductor substrate cleaning composition.

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

11. The semiconductor substrate cleaning composition according to any one of claims 1 to 10, wherein the content of said component (E) is 0.1 to 50 mass % based on the total amount of said semiconductor substrate cleaning composition.

12. The composition for cleaning semiconductor substrates according to any one of claims 1 to 11, 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.

13. A semiconductor substrate cleaning composition according to any one of claims 1 to 12, which removes titanium nitride at a removal rate of 80 Å / min or more and removes tungsten at a removal rate of 3 Å / min or less when a substrate having tungsten and titanium nitride is immersed in the semiconductor substrate cleaning composition and stored at 60°C.

14. A 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, the titanium nitride is removed at a removal rate of 80 Å / min or more and the low dielectric constant interlayer insulating film is removed at a removal rate of 3 Å / min or less.

15. A method for cleaning a semiconductor substrate, which comprises contacting a substrate having titanium nitride, tungsten and a low dielectric constant interlayer insulating film with the semiconductor substrate cleaning composition according to any one of claims 1 to 14.

16. A method for producing a semiconductor substrate, comprising the step of contacting a substrate having titanium nitride, tungsten and a low dielectric constant interlayer insulating film with the semiconductor substrate cleaning composition according to any one of claims 1 to 14.

Images