Composition for cleaning a semiconductor substrate, method for cleaning a semiconductor substrate, and method for manufacturing a semiconductor substrate
Patent Information
- Application Number
- KR1020267016932
- Authority / Receiving Office
- KR · KR
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-12-13
- Filing Date
- 2024-12-11
- Publication Date
- 2026-08-14
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Abstract
Description
Technology Field
[0001] The present invention relates to a composition for cleaning a semiconductor substrate, a method for cleaning a semiconductor substrate, and a method for manufacturing a semiconductor substrate. Background Technology
[0002] In the manufacture of a semiconductor substrate in which semiconductor devices are highly integrated, typically, a conductive thin film, such as a metal film serving as a conductive wiring, a low dielectric constant interlayer insulating film for insulating between conductive thin films, a hard mask, etc., are formed on a substrate such as a silicon wafer, and then a photosensitive layer is prepared by homogeneously applying a photoresist to the surface, and a desired photoresist pattern is created by performing selective exposure and development processes on it. Subsequently, a desired pattern is formed on the substrate by performing a dry etching process on the substrate, which has the low dielectric constant interlayer insulating film or hard mask, etc., stacked thereon, using this photoresist pattern as a mask. Then, a series of processes is generally taken to remove residues or hard masks generated by the photoresist pattern and dry etching process using oxygen plasma ashing or a cleaning solution.
[0003] Recently, titanium nitride is widely used as a hard mask. In addition, copper, cobalt, tungsten, etc. are used for metal wiring.
[0004] In a semiconductor substrate in which titanium nitride is used as a hard mask and titanium nitride coexists with metal wiring or a low dielectric constant interlayer insulating film on the surface, it is required to remove titanium nitride without corroding the metal wiring or the low dielectric constant interlayer insulating film.
[0005] As a method to remove titanium nitride by wet etching without corroding metal wiring, a cleaning method using a corrosion inhibitor is being considered.
[0006] For example, Patent Document 1 discloses a liquid composition having a pH value of 0 to 4, comprising an oxidizing agent including potassium permanganate, a fluorine compound, and two types of compounds such as alkylamines, for the purpose of removing titanium nitride without corroding tungsten, etc.
[0007] Patent Document 2 discloses a composition comprising an oxidizing agent, an etching solution, and a solvent, and substantially not containing hydrogen peroxide, for the purpose of selectively removing titanium nitride and photoresist etching residue materials.
[0008] Patent Document 3 discloses a composition comprising an oxidizing agent, an etchant, a corrosion inhibitor, a silica source, water, and an organic solvent, and substantially not containing hydrogen peroxide, for the purpose of selectively removing titanium nitride and photoresist etch residue.
[0009] Patent Document 4 discloses a composition comprising 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 etch residue material from the surface of a microelectronic device. Prior art literature
[0010] International Publication No. 2015 / 111684, Japanese Patent Publication No. 2015-506583, Japanese Patent Publication No. 2016-510175, Japanese Patent Publication No. 2016-527707 The problem to be solved
[0011] With the high integration of semiconductor devices, the miniaturization of metal wiring on semiconductor substrates is also required. With the miniaturization of metal wiring, there is concern about the diffusion of metal atoms forming the wiring into the semiconductor device. Under these circumstances, the use of tungsten, which has low atomic diffusion, for metal wiring is being considered. However, there was a problem where the tungsten corrosion inhibitor was precipitated when the amount of tungsten corrosion inhibitor added was increased in order to secure sufficient tungsten corrosion resistance while maintaining the removal capability of titanium nitride.
[0012] Meanwhile, if the amount of oxidizing agent used in the liquid composition disclosed in Patent Document 1 is reduced, the corrosion of tungsten is suppressed. However, the removal rate of titanium nitride is reduced. To compensate for this, if the amount of fluorine compound is increased, corrosion of the low dielectric constant interlayer insulating film composed of silicon dioxide, etc. occurs. Thus, in the manufacture of a semiconductor substrate in which tungsten is used for metal wiring and titanium nitride is used for the hard mask, it is very difficult to remove titanium nitride without corroding the metal wiring or the low dielectric constant interlayer insulating film. Therefore, in the manufacture of a semiconductor substrate in which tungsten is used for metal wiring and titanium nitride is used for the hard mask, there has been a demand for a semiconductor substrate cleaning composition capable of removing titanium nitride without corroding the metal wiring or the low dielectric constant interlayer insulating film.
[0013] 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. means of solving the problem
[0014] As a result of careful consideration to solve the above problem, the applicant of the present invention discovered that by adding a specific organic solvent to a composition for cleaning semiconductor substrates, the amount of tungsten corrosion inhibitor can be increased without precipitation of the tungsten corrosion inhibitor, and sufficient tungsten corrosion resistance can be secured while maintaining the removal capability of titanium nitride, and thus completed the present invention.
[0015] That is, the present invention provides the following composition for cleaning a semiconductor substrate, a method for cleaning a semiconductor substrate, and a method for manufacturing a semiconductor substrate.
[0016] <1> Component (A): At least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base,
[0017] [MF n ] (n-k)- (a)
[0018] Component (B): A compound represented by the following general formula (b),
[0019] [MO m (OR) k-2m ] x (b)
[0020] (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 greater than or equal to k / 2; x is a positive integer; R is one selected from the group consisting of hydrogen atoms, alkali metals, and alkyl groups; and n is the coordination number of the fluoride ion for M.)
[0021] Component (C): Oxidizing agent,
[0022] Ingredient (D): Tungsten corrosion inhibitor,
[0023] Component (E): Organic solvent, and
[0024] Component (F): Contains water,
[0025] The above component (E) comprises at least one selected from the group consisting of tetrahydrofuran, acetone, and acetonitrile, and
[0026] It is a composition for cleaning a semiconductor substrate, wherein α represented by the following formula (I) is 0.2 or more and 1.1 or less.
[0027] [Mathematical Formula 1]
[0028]
[0029] (In Equation (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.)
[0030] <2> The above 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, wherein <1> It is a composition for cleaning semiconductor substrates as described in [document].
[0031] <3> The above component (B) comprises at least one selected from the group consisting of boric acid, a salt of boric acid, silicic acid, a salt of silicic acid, orthosilicic acid, and a salt of orthosilicic acid, wherein <1> or <2> It is a composition for cleaning semiconductor substrates as described in [document].
[0032] <4> The above component (C) comprises at least one selected from the group consisting of vanadium oxide (V), vanadic acid (V), a salt of vanadic acid (V), iodic acid, a salt of iodic acid, orthoperiodic acid, and a salt of orthoperiodic acid. <1> ~ <3> It is a composition for cleaning a semiconductor substrate as described in any one of the above.
[0033] <5> The above component (D) comprises at least one selected from the group consisting of benzethonium chloride, benzalkonium chloride, alkylpyridinium chloride, and quaternary ammonium salts, wherein <1> ~ <4> It is a composition for cleaning a semiconductor substrate as described in any one of the above.
[0034] <6> The above, used to remove titanium nitride from a semiconductor substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film. <1> ~ <5> It is a composition for cleaning a semiconductor substrate as described in any one of the above.
[0035] <7> The above component (A) has a content of 0.1 to 10 mass% with respect to the total amount of the semiconductor substrate cleaning composition. <1> ~ <6> It is a composition for cleaning a semiconductor substrate as described in any one of the above.
[0036] <8> The above component (B) has a content of 0.005 to 5 mass% relative to the total amount of the semiconductor substrate cleaning composition. <1> ~ <7> It is a composition for cleaning a semiconductor substrate as described in any one of the above.
[0037] <9> The above component (C) has a content of 0.0005 to 1 mass% relative to the total amount of the semiconductor substrate cleaning composition. <1> ~ <8> It is a composition for cleaning a semiconductor substrate as described in any one of the above.
[0038] <10> The content of the above component (D) is 0.0005 to 1 mass% with respect to the total amount of the semiconductor substrate cleaning composition, the above <1> ~ <9> It is a composition for cleaning a semiconductor substrate as described in any one of the above.
[0039] <11> The above component (E) has a content of 0.1 to 50 mass% with respect to the total amount of the semiconductor substrate cleaning composition. <1> ~ <10> It is a composition for cleaning a semiconductor substrate as described in any one of the above.
[0040] <12> The above 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 the acid having an anion represented by the general formula (a) as a conjugate base, wherein the ratio [(A) / (B)] of the content (mol) of the above component (A) and the content (mol) of the above component (B) is 1 to 100. <1> ~ <11> It is a composition for cleaning a semiconductor substrate as described in any one of the above.
[0041] <13> A substrate having tungsten and titanium nitride is immersed in the above semiconductor substrate cleaning composition and stored at 60°C, wherein titanium nitride is removed at a removal rate of 80 Å / min or more, and the removal rate of tungsten is 3 Å / min or less, the above <1> ~ <12> It is a composition for cleaning a semiconductor substrate as described in any one of the above.
[0042] <14> A substrate having a low dielectric constant interlayer insulating film and titanium nitride is immersed in the above semiconductor substrate cleaning composition and stored at 60°C, wherein titanium nitride is removed 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, the above <1> ~ <12> It is a composition for cleaning a semiconductor substrate as described in any one of the above.
[0043] <15> The above <1> ~ <14> A method for cleaning a semiconductor substrate, wherein a semiconductor substrate cleaning composition described in any one of the above is brought into contact with a substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film.
[0044] <16> The above <1> ~ <14> A method for manufacturing a semiconductor substrate comprising a process of contacting a semiconductor substrate cleaning composition described in any one of the above with a substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film. Effects of the invention
[0045] 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.
[0046] That is, by using the semiconductor substrate cleaning composition of the present invention, titanium nitride can be removed while particularly inhibiting the corrosion of tungsten.
[0047] As a result, it becomes possible to clean and manufacture semiconductor substrates with miniaturized metal wiring, enabling high integration of semiconductor devices. Specific details for implementing the invention
[0048] The present invention comprises: at least one selected from the group consisting of component (A): hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base,
[0049] [MF n ] (n-k)- (a)
[0050] Component (B): A compound represented by the following general formula (b),
[0051] [MO m (OR) k-2m ] x (b)
[0052] (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 greater than or equal to k / 2; x is a positive integer; R is one selected from the group consisting of hydrogen atoms, alkali metals, and alkyl groups; and n is the coordination number of the fluoride ion for M.)
[0053] A semiconductor substrate cleaning composition comprising: component (C): an oxidizing agent, component (D): a tungsten corrosion inhibitor, component (E): an organic solvent, and component (F): water, wherein the component (E) comprises 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; a cleaning method using the semiconductor substrate cleaning composition; and a method for manufacturing a semiconductor substrate.
[0054] [Mathematical Formula 2]
[0055]
[0056] (In Equation (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.)
[0057] [Composition for cleaning semiconductor substrates]
[0058] The semiconductor substrate cleaning composition of the present invention is,
[0059] Component (A): At least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base,
[0060] [MF n ] (n-k)- (a)
[0061] Component (B): A compound represented by the following general formula (b),
[0062] [MO m (OR) k-2m ] x (b)
[0063] (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 greater than or equal to k / 2; x is a positive integer; R is one selected from the group consisting of hydrogen atoms, alkali metals, and alkyl groups; and n is the coordination number of the fluoride ion for M.)
[0064] Component (C): oxidizing agent, Component (D): tungsten corrosion inhibitor, Component (E): organic solvent, and Component (F): water, wherein the above-mentioned Component (E) comprises 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.
[0065] [Mathematical Formula 3]
[0066]
[0067] (In Equation (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.)
[0068] The semiconductor substrate cleaning composition of the present invention comprises the above components, and by α being a specific value, titanium nitride can be selectively removed from a semiconductor substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film. Although the reason for having such excellent properties is not certain, it is thought as follows.
[0069] Fluoride ions, which are ions constituting the above component (A), are necessary to remove titanium nitride, but at the same time, they corrode tungsten and low dielectric constant interlayer insulating films. In the semiconductor substrate cleaning composition of the present invention, by including a compound having a specific element as a central element, which is component (B), to satisfy a specific value of α, the nucleation of the fluorine compound is appropriately reduced, so that corrosion of tungsten, etc. can be suppressed while removing titanium nitride.
[0070] Below, the composition for cleaning a semiconductor substrate according to the present invention will be described in detail.
[0071] <Ingredient (A)>
[0072] The semiconductor substrate cleaning composition of the present invention comprises at least one component (A) selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base.
[0073] [MF n ] (n-k)- (a)
[0074] (In formula (a), M is at least one element selected from the group consisting of boron, silicon, zirconium, antimony, niobium, aluminum, phosphorus, and titanium, k is the oxidation number of M, and n is the coordination number of the fluoride ion for M.)
[0075] That is, component (A) is at least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the 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.
[0076] Component (A) releases fluoride ions during cleaning and plays a role in assisting in the removal of titanium nitride.
[0077] Among these, preferably, at least one is selected from the group consisting of hydrofluoric acid and an acid having an anion represented by the general formula (a) as a conjugate base, and more preferably, an acid having an anion represented by the general formula (a) as a conjugate base.
[0078] Examples of salts of hydrofluoric acid include sodium fluoride, potassium fluoride, ammonium fluoride, acidic sodium fluoride, acidic potassium fluoride, and acidic ammonium fluoride.
[0079] In formula (a) representing an anion constituting an acid or its salt having an anion represented by the above 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.
[0080] Also, k is the oxidation number of M and varies depending on M. Generally, k is 3 for boron, 4 for silicon, 4 for zirconium, 5 for phosphorus, and 4 for titanium.
[0081] n is the coordination number of the fluoride ion for 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.
[0082] Acids having an anion represented by the above general formula (a) as a conjugate base include hexafluorosilicic acid, tetrafluoroboric acid, hexafluorozirconic acid, hexafluoroantimonic acid, hexafluoroniobium acid, hexafluoroaluminate acid, hexafluorotitanic acid, hexafluorophosphate, etc.
[0083] Examples of acid salts having an anion represented by the above 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 hexafluoroniobium acid, salts of hexafluoroaluminate acid, salts of hexafluorotitanic acid, salts of hexafluorophosphate, etc.
[0084] Examples of cations constituting the above salt include sodium ions, potassium ions, and ammonium ions. That is, as a salt of an acid having an anion represented by the above general formula (a) as a conjugate base, examples include salts in which the hydrogen ions of each acid are substituted with the above cations. Examples of specific salts include ammonium hexafluorophosphate.
[0085] In terms of achieving compatibility between the removal of titanium nitride and the inhibition of corrosion of tungsten and low dielectric constant interlayer insulating films, component (A) preferably 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; more preferably comprises 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 comprises at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, and tetrafluoroboric acid; and even more preferably, hexafluorosilicic acid and It includes at least one selected from the group consisting of tetrafluoroboric acid.
[0086] Furthermore, as a suitable embodiment, preferably, at least one is selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, tetrafluoroboric acid, hexafluorozirconic acid, hexafluorotitanic acid, hexafluorophosphoric acid, salt of hexafluorosilicic acid, salt of tetrafluoroboric acid, salt of hexafluorozirconic acid, salt of hexafluorotitanic acid, and salt of hexafluorophosphoric acid; more preferably, at least one is 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 is selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, and tetrafluoroboric acid; and even more preferably, at least one is selected from the group consisting of hexafluorosilicic acid and tetrafluoroboric acid.
[0087] The semiconductor substrate cleaning composition of the present invention may contain only one type of component (A), but may contain two or more types. For example, it may contain both hydrofluoric acid and an acid having an anion represented by the general formula (a) as a conjugate base, or it may contain two or more types of acids having an anion represented by the general formula (a) as a conjugate base.
[0088] The content of component (A) in the semiconductor substrate cleaning composition of the present invention is preferably 0.1 to 10 mass% with respect to the total amount of the semiconductor substrate cleaning composition, more preferably 0.3 to 8.0 mass%, even more preferably 0.5 to 6.0 mass%, and even more preferably 1.0 to 5.0 mass%. By having the content of component (A) within the above range, titanium nitride can be removed while suppressing corrosion of tungsten and low dielectric constant interlayer insulating films.
[0089] <Component (B)>
[0090] The semiconductor substrate cleaning composition of the present invention comprises a component (B) which is a compound represented by the following general formula (b).
[0091] [MO m (OR) k-2m ] x (b)
[0092] (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 between 0 and k / 2; x is a positive integer; and R is one selected from the group consisting of hydrogen atoms, alkali metals, and alkyl groups.)
[0093] It is thought that component (B) achieves the removal of titanium nitride and the inhibition of corrosion of tungsten and low dielectric constant interlayer insulating films by appropriately reducing the nucleation of component (A).
[0094] In formula (b) representing a 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.
[0095] Also, k is the oxidation number of M and varies depending on M. Generally, k is 3 for boron, 4 for silicon, 4 for zirconium, 5 for phosphorus, and 4 for titanium.
[0096] R is one selected from the group consisting of hydrogen atoms, alkali metals, and alkyl groups. That is, if R is a hydrogen atom, component (B) is a compound having a hydroxyl group; if R is an alkali metal, component (B) is a salt of an acid with M as the central metal; and if R is an alkyl group, component (B) is an alkoxide.
[0097] m is an integer greater than or equal to k / 2. When m is k / 2, component (B) is an oxide of M.
[0098] 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. When x is 2 or more, component (B) preferably has a cyclic structure.
[0099] In terms of achieving the removal of titanium nitride and the inhibition of corrosion of tungsten and low dielectric constant interlayer insulating films, component (B) preferably comprises at least one selected from the group consisting of boric acid, salt of boric acid, silicon dioxide, silicic acid, salt of silicic acid, orthosilicic acid, salt of orthosilicic acid, alkoxysilane, zirconium oxide, zirconic acid, and salt of zirconic acid, more preferably comprises at least one selected from the group consisting of boric acid, silicon dioxide, silicic acid, and salt of silicic acid, even more preferably comprises at least one selected from the group consisting of boric acid, silicon dioxide, and salt of silicic acid, and even more preferably comprises at least one selected from the group consisting of boric acid and salt of silicic acid.
[0100] Furthermore, in a suitable embodiment, component (B) is preferably at least one selected from the group consisting of boric acid, salt of boric acid, silicon dioxide, silicic acid, salt of silicic acid, orthosilicic acid, salt of orthosilicic acid, alkoxysilane, zirconium oxide, zirconic acid, and salt of zirconic acid, more preferably at least one selected from the group consisting of boric acid, silicon dioxide, silicic acid, and salt of silicic acid, even more preferably at least one selected from the group consisting of boric acid, silicon dioxide, and salt of silicic acid, and even more preferably at least one selected from the group consisting of boric acid and salt of silicic acid.
[0101] Examples of cations constituting the above salt include sodium ions, potassium ions, and ammonium ions. That is, salts of boric acid, silicic acid, orthosilicic acid, and zirconic acid in which the hydrogen ions of each acid are substituted with the above cations may be examples. Examples of specific salts include sodium metasilicate and potassium silicate.
[0102] The semiconductor substrate cleaning composition of the present invention may include only one type of component (B), but may include two or more types.
[0103] The content of component (B) in the semiconductor substrate cleaning composition of the present invention is preferably 0.005 to 5 mass% with respect to the total amount of the semiconductor substrate cleaning composition, more preferably 0.01 to 3.0 mass%, even more preferably 0.02 to 2.0 mass%, and even more preferably 0.03 to 1.0 mass%. By having the content of component (B) within the above range, titanium nitride can be removed while suppressing corrosion of tungsten and low dielectric constant interlayer insulating films.
[0104] <Component (C): Oxidizing Agent>
[0105] The semiconductor substrate cleaning composition of the present invention includes a component (C) which is an oxidizing agent.
[0106] Component (C) is included in the composition to efficiently remove titanium nitride.
[0107] Component (C) can use a generally known oxidizing agent.
[0108] Among these, component (C) is preferably at least one selected from the group consisting of vanadium oxide (V), vanadic acid (V), salt of vanadic acid (V), permanganic acid, salt of permanganic acid, iodic acid, salt of iodic acid, ortho-periodic acid, salt of ortho-periodic acid, perchloric acid, salt of perchloric acid, cerium diammonium nitrate (IV), iron ammonium sulfate (III), ammonium peroxodisulfate, iron chloride (III), ammonium nitrate, t-butylhydroperoxide, N-methylmorpholine N-oxide, and trimethylamine N-oxide, with the view of achieving both removal of titanium nitride and inhibition of corrosion of tungsten and low dielectric constant interlayer insulating film; more preferably, vanadium oxide (V), salt of permanganic acid, iodic acid, salt of iodic acid, periodic acid, At least one selected from the group consisting of perchloric acid, salt of perchloric acid, cerium diammonium nitrate (IV), iron ammonium sulfate (III), ammonium peroxodisulfate, ammonium nitrate, and N-methylmorpholine N-oxide, and more preferably at least one selected from the group consisting of vanadium oxide (V), iodic acid, and periodic acid.
[0109] Examples of cations constituting the above salt include sodium ions, potassium ions, and ammonium ions. That is, salts of vanadic acid (V), permanganate, iodic acid, orthoperiodic acid, and perchloric acid may be examples, in which the hydrogen ions of each acid are substituted with the above cations. As a specific example of a salt, potassium permanganate may be cited.
[0110] The semiconductor substrate cleaning composition of the present invention may contain only one type of component (C), but may contain two or more types.
[0111] The content of component (C) in the semiconductor substrate cleaning composition of the present invention is preferably 0.0005 to 1 mass% with respect to the total amount of the semiconductor substrate cleaning composition, more preferably 0.0008 to 0.2 mass%, even more preferably 0.0010 to 0.1 mass%, even more preferably 0.0010 to 0.05 mass%, and particularly preferably 0.0015 to 0.03 mass%. By having the content of component (C) within the above range, titanium nitride can be removed while suppressing corrosion of tungsten and low dielectric constant interlayer insulating films.
[0112] 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 desirable not to use oxidizing agents with strong oxidizing power as much as possible, and even if used, it is desirable to limit the amount to an extremely small amount.
[0113] The semiconductor substrate cleaning composition of the present invention preferably does not substantially contain hydrogen peroxide, p-benzoquinone, copper(II) nitrate, sodium peroxoborate, bromic acid, or a salt of bromic acid. "Substantially not containing" means that the content is less than or equal to an amount that does not impair the effect of the semiconductor substrate cleaning composition of the present invention.
[0114] When hydrogen peroxide, p-benzoquinone, copper(II) nitrate, sodium peroxoborate, bromic acid, or a salt of bromic acid are included, 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 even more preferably less than 0.0005 mass% with respect to the total amount of the semiconductor substrate cleaning composition, and it is even more preferable not to include hydrogen peroxide, p-benzoquinone, copper(II) nitrate, sodium peroxoborate, bromic acid, or a salt of bromic acid.
[0115] <Component (D): Tungsten Corrosion Resist>
[0116] The semiconductor substrate cleaning composition of the present invention includes a component (D) which is a tungsten corrosion inhibitor.
[0117] The tungsten corrosion inhibitor used in the present invention may use any known tungsten corrosion inhibitor without any particular limitations.
[0118] Examples include 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, alkylpyridinium chloride, fluoroalkyl quaternary pyridinium salts, alkyl quaternary bipyridinium salts, fluoroalkyl quaternary bipyridinium salts, alkyl quaternary imidazolium salts, and fluoroalkyl quaternary imidazolium salts.
[0119] Specific examples of alkylamines and their salts or fluoroalkylamines and their salts include, for example, 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.
[0120] Specific examples of alkylamine oxides or fluoroalkylamine oxides include, for instance, N-decyl-N,N-dimethylamine oxide, N-dodecyl-N,N-dimethylamine oxide, N-tetradecyl-N,N-dimethylamine oxide, N-hexadecyl-N,N-dimethylamine oxide, Suflon S-241 (trade name, perfluoroalkylamine oxide manufactured by AGC Seimi Chemical Co., Ltd.), and Armogen (trade name, alkylamine oxide manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.). Among these, Suflon S-241 is preferred.
[0121] Specific examples of alkyl betaines or fluoroalkyl betaines include, for instance, dodecyl dimethylaminoacetic acid betaine, perfluorododecyl dimethylaminoacetic acid betaine, dodecyl dimethylaminosulfobetaine, perfluorododecyl dimethylaminosulfobetaine, and amphitol (trade name, Alkyl Betaine manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.). Among these, amphitol 20YB and amphitol 24B are preferred.
[0122] Specific examples of alkyl quaternary ammoniums and their salts or fluoroalkyl quaternary ammoniums and their salts include, for example, 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, Examples include benzyldimethylhexadecylammonium chloride, benzalkonium chloride, benzethonium chloride, Esocard (product name, polyoxyethylene addition type quaternary ammonium chloride manufactured by Lion Corporation), and Fluorad FC-135 (product name, perfluoroalkyl quaternary ammonium iodide manufactured by Sumitomo 3M Corporation), Queramin (product name, alkyl quaternary ammonium chloride manufactured by Kao Corporation), and Cathiogen (product name, alkyl quaternary ammonium ethyl sulfate manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.). Among these, benzalkonium chloride, benzethonium chloride, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, and Fluorad FC-135 are preferred.
[0123] Specific examples of alkylpyridinium chloride or fluoroalkyl quaternary pyridinium salts include, for example, 1-decylpyridinium chloride, 1-dodecylpyridinium chloride, 1-tetradecylpyridinium chloride, 1-hexadecylpyridinium chloride, and 1-hexadecyl-4-methylpyridinium chloride. Among these, 1-dodecylpyridinium chloride and 1-hexadecyl-4-methylpyridinium chloride are preferred.
[0124] Specific examples of alkyl quaternary bipyridinium salts or fluoroalkyl quaternary bipyridinium salts include, for example, 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. Among these, 1,1'-di-n-octyl-4,4'-bipyridinium dibromide is preferred.
[0125] Specific examples of alkyl quaternary imidazolium salts or fluoroalkyl quaternary imidazolium salts include, for example, 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-perfluorooctylimidazolium 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.
[0126] Other tungsten corrosion inhibitors include polyoxyalkylene alkylamine, polyoxyalkylene fluoroalkylamine, polyoxyalkylene alkyl ether, polyoxyalkylene fluoroalkyl ether, polyoxyalkylene alkyl phosphate ester, polyoxyalkylene fluoroalkyl phosphate ester, polyoxyalkylene alkyl ether sulfate, polyoxyalkylene fluoroalkyl ether sulfate, alkyl diphenyl ether sulfonate, and fluoroalkyl diphenyl ether sulfonate.
[0127] Specific examples of polyoxyalkylene alkylamine or polyoxyalkylene fluoroalkylamine include, for instance, Naimin (trade name, polyoxyethylene alkylamine manufactured by Nippon Oil & Fat Co., Ltd.) and Neugen (trade name, polyoxyethylene alkylamine manufactured by Daiichi Industrial Pharmaceutical Co., Ltd.). Among these, Naimin F-215, Neugen ET-189, and Neugen XL-140 are preferred.
[0128] Specific examples of polyoxyalkylene alkyl ethers or polyoxyalkylene fluoroalkyl ethers include, for instance, Nucol (trade name, alkyl ether type nonionic surfactant manufactured by Nippon Yuhwas Co., Ltd.), Ptergent (trade name, polyoxyethylene perfluoroalkyl ether manufactured by Neos Co., Ltd.), and Antipros (trade name, special nonionic surfactant manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.). Among these, Nucol 2308-LY, Antipros M-9, Ptergent 222F, Ptergent 250, and Ptergent 251 are preferred.
[0129] Specific examples of polyoxyalkylene alkyl phosphate esters or polyoxyalkylene fluoroalkyl phosphate esters include, for example, phosphanol (trade name: Polyoxyethylene phosphate ester manufactured by Toho Chemical Industry Co., Ltd.). Among these, phosphanol RA-600, phosphanol RS-710, phosphanol RL-310, phosphanol ED-230, phosphanol iD10-P, phosphanol ML-240, and phosphanol OF-100 are preferred.
[0130] Specific examples of polyoxyalkylene alkyl ether sulfates or polyoxyalkylene fluoroalkyl ether sulfates include, for example, Hytenol (trade name: Polyoxyethylene alkyl ether sulfonic acid manufactured by Daiichi Pharmaceutical Co., Ltd.). Among these, Hytenol NF-08, Hytenol NF-13, and Hytenol NF-17 are preferred.
[0131] Specific examples of alkyl diphenyl ether sulfonates or fluoroalkyl diphenyl ether sulfonates include, for instance, Perex (trade name, alkyl diphenyl ether disulfonate manufactured by Kao Corporation). Among these, Perex SS-H and Perex SS-L are preferred.
[0132] In the present invention, it is preferable that the component (D) comprises at least one selected from the group consisting of benzethonium chloride, benzalkonium chloride, alkylpyridinium chloride, and quaternary ammonium salt.
[0133] The content of component (D) in the semiconductor substrate cleaning composition of the present invention is preferably 0.0005 to 1 mass% with respect to the total amount of the semiconductor substrate cleaning composition, 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%. By having the content of component (D) within the above range, sufficient tungsten corrosion protection performance is obtained. If the content of the tungsten corrosion protection agent is less than 0.0005 mass%, sufficient corrosion protection performance may not be obtained, and if it exceeds 1 mass%, it is not economical and unsuitable for practical use, and precipitation may occur.
[0134] <Component (E): Organic Solvent>
[0135] The semiconductor substrate cleaning composition of the present invention comprises a component (E) which is an organic solvent.
[0136] In the present invention, component (E) comprises at least one selected from the group consisting of tetrahydrofuran, acetone, and acetonitrile.
[0137] By adding such a specific organic solvent, the amount of tungsten corrosion inhibitor added can be increased without precipitation of the tungsten corrosion inhibitor, and sufficient tungsten corrosion resistance can be secured while maintaining the removal capability of titanium nitride.
[0138] The content of component (E) in the semiconductor substrate cleaning composition of the present invention is preferably 0.1 to 50 mass% with respect to the total amount of the semiconductor substrate cleaning composition, more preferably 0.5 to 20 mass%, even more preferably 1.0 to 15 mass%, and even more preferably 2.0 to 10 mass%.
[0139] <Component (F): Water>
[0140] The semiconductor substrate cleaning composition of the present invention comprises a component (F) which is water.
[0141] Water is not particularly limited, but it is preferable that impurities such as metal ions, organic matter, and particles be removed by distillation, ion exchange treatment, filtration treatment, various adsorption treatments, etc. Pure water is more preferable, and ultrapure water is particularly preferable.
[0142] The water content is the remainder excluding the above components (A) to (E) and other additives from the semiconductor substrate cleaning composition of the present invention, and is preferably 70 mass% or more and more preferably 80 to 95 mass% with respect to the total amount of the semiconductor substrate cleaning composition. If the water content is within the above range, the effects of the present invention can be achieved, making it more economical.
[0143] <Characteristics of composition for semiconductor substrate cleaning, etc.>
[0144] The semiconductor substrate cleaning composition of the present invention comprises the above components (A) to (F), and α represented by the following formula (I) is 0.2 or more and 1.1 or less.
[0145] [Mathematical Formula 4]
[0146]
[0147] (In Equation (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.)
[0148] Here, α is a value represented by the above formula (I), which represents the ratio of the fluoride ion included in the above component (A) and the element represented by M included in the above components (A) and (B).
[0149] It is thought that by having α in the range of 0.2 or more and 1.1 or less, the element included in component (B) forms a fluoro complex (an fluorine-coordinated phosphate complex) with the fluoride ion included in component (A), and by gradually supplying the fluoride ion through an equilibrium reaction, the nucleation of the fluoride compound is appropriately reduced, and corrosion of tungsten, etc., can be suppressed while removing titanium nitride.
[0150] α is 0.2 or higher, preferably 0.4 or higher, more preferably 0.7 or higher, and also 1.1 or lower, preferably 1.05 or lower, more preferably 1.0 or lower. By having α within the above range, titanium nitride can be removed while suppressing corrosion of tungsten and low dielectric constant interlayer insulating films.
[0151] In equation (I), α is obtained by dividing the molar concentration of the fluoride ion ([F]) in the composition of M by the product of the coordination number of the fluoride ion with respect to M (n(M)) and the molar concentration of the composition of M ([M]).
[0152] 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.
[0153] When multiple elements M are used in components (A) and (B), α is obtained by dividing the molar concentration ([F]) in the composition of fluoride ions by the sum of the products of the coordination number (n(M)) of the fluoride ions for each M and the molar concentration in the composition of each M.
[0154] For example, if M consists of two types of M, M1 and M2, the denominator of the right-hand side in the above equation (I) becomes (n1(M1)·[M1]+n2(M2)·[M2]). Here, [M1] is the molar concentration in the composition of M1, n1(M1) is the coordination number of fluoride ions for M1, [M2] is the molar concentration in the composition of M2, and n2(M2) is the coordination number of fluoride ions for M2.
[0155] When component (A) is at least one selected from the group consisting of an acid having an anion represented by the above general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base, the ratio of the content (mol) of component (A) to the content (mol) of component (B) [(A) / (B)] is preferably 1 to 100, more preferably 2 to 50, even more preferably 4 to 40, even more preferably 4 to 20, and particularly preferably 8 to 20. By having the ratio of the molar content of component (A) to the molar content of component (B) within the above range, titanium nitride can be removed while suppressing corrosion of tungsten and low dielectric constant interlayer insulating film.
[0156] Meanwhile, when calculating the above ratio, the “content (mol) of component (B)” is the amount obtained by multiplying the actual content of component (B) included in the semiconductor substrate cleaning composition by x when x in the formula (b) representing the compound of component (B) exceeds 1.
[0157] 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 within the above range, corrosion of tungsten can be particularly inhibited.
[0158] The semiconductor substrate cleaning composition of the present invention is used to remove titanium nitride from a semiconductor substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film as described above. That is, the semiconductor substrate cleaning composition of the present invention is a semiconductor substrate cleaning composition used to remove titanium nitride from a semiconductor substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film.
[0159] More specifically, the semiconductor substrate cleaning composition of the present invention is a semiconductor substrate cleaning composition used to remove titanium nitride from a semiconductor substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film, wherein
[0160] Component (A): At least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base,
[0161] [MF n ] (n-k)- (a)
[0162] Component (B): A compound represented by the following general formula (b),
[0163] [MO m (OR) k-2m ] x (b)
[0164] (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 greater than or equal to k / 2; x is a positive integer; R is one selected from the group consisting of a hydrogen atom, an alkali metal, and an alkyl group; and n is the coordination number of the fluoride ion for M.)
[0165] A semiconductor substrate cleaning composition comprising: component (C): an oxidizing agent, component (D): a tungsten corrosion inhibitor, component (E): an organic solvent, and component (F): water, wherein the component (E) comprises 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.
[0166] [Mathematical Formula 5]
[0167]
[0168] (In Equation (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.)
[0169] The semiconductor substrate cleaning composition of the present invention is preferably such that when a substrate having tungsten 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 80 Å / min or more, and the removal rate of tungsten is 3 Å / min or less.
[0170] The semiconductor substrate cleaning composition of the present invention, by having the above-described properties, can selectively remove titanium nitride from a semiconductor substrate containing tungsten. That is, by using the semiconductor substrate cleaning composition of the present invention, titanium nitride can be removed, particularly while suppressing the corrosion of tungsten. As a result, it becomes possible to clean and manufacture semiconductor substrates with finely miniaturized metal wiring, thereby enabling high integration of semiconductor devices.
[0171] Under the above conditions, the removal rate of titanium nitride is preferably 80 Å / min or more, more preferably 120 Å / min or more, and even more preferably 160 Å / min or more. Under the above conditions, the higher the removal rate of titanium nitride, the more efficiently titanium nitride can be removed, which is desirable, and is typically 500 Å / min or less.
[0172] Under the above conditions, the tungsten removal rate is preferably 3 Å / min or less, more preferably 2 Å / min or less, and even more preferably 1 Å / min or less. Under the above conditions, the lower the tungsten removal rate, the more tungsten corrosion can be suppressed, which is desirable, and is typically 0.1 Å / min or more.
[0173] Under the above conditions, the ratio of the removal rate of titanium nitride to the removal rate of tungsten is preferably 25 or higher, more preferably 50 or higher, and even more preferably 100 or higher. Under the above conditions, the larger the ratio of the removal rate of titanium nitride to the removal rate of tungsten, the more selectively titanium nitride can be removed from the semiconductor substrate having tungsten, which is desirable, and is typically 5000 or lower.
[0174] The specific measurement method and conditions are as described in “(1) Etching Rate (ER)” of the example.
[0175] The semiconductor substrate cleaning composition of the present invention is preferably such that 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 80 Å / min or more, and the removal rate of the low dielectric constant interlayer insulating film is 3 Å / min or less.
[0176] The semiconductor substrate cleaning composition of the present invention, by having the above-described properties, can selectively remove titanium nitride from a semiconductor substrate having a low dielectric constant interlayer insulating film. Consequently, it becomes possible to clean and manufacture semiconductor substrates with finely miniaturized metal wiring, thereby enabling high integration of semiconductor devices.
[0177] Under the above conditions, the removal rate of titanium nitride is preferably 80 Å / min or more, more preferably 120 Å / min or more, and even more preferably 160 Å / min or more. Under the above conditions, the higher the removal rate of titanium nitride, the more efficiently titanium nitride can be removed, which is desirable, and is typically 500 Å / min or less.
[0178] Under the above conditions, the removal rate of the low dielectric constant interlayer insulating film is preferably 3 Å / min or less, more preferably 2 Å / min or less, and even more preferably 1 Å / min or less. Under the above conditions, the smaller the removal rate of the low dielectric constant interlayer insulating film, the more selectively titanium nitride can be removed from the semiconductor substrate having the low dielectric constant interlayer insulating film, which is desirable, and is typically 0.1 Å / min or more.
[0179] Under the above conditions, the ratio of the removal rate of titanium nitride to the removal rate of the low dielectric constant interlayer insulating film is preferably 25 or higher, more preferably 50 or higher, and even more preferably 100 or higher. Under the above conditions, the larger the ratio of the removal rate of titanium nitride to the removal rate of the low dielectric constant interlayer insulating film, the more desirable it is for selectively removing titanium nitride from a semiconductor substrate having a low dielectric constant interlayer insulating film, and is typically 5000 or lower.
[0180] The specific measurement method and conditions are as described in “(1) Etching Rate (ER)” of the example.
[0181] The above 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.
[0182] A carbon-doped silicon dioxide film is preferred for the silicon dioxide film.
[0183] Among TEOS films, preferably, it is a PE-TEOS film (plasma TEOS film).
[0184] [Cleaning Method for Semiconductor Substrates]
[0185] The semiconductor substrate cleaning method of the present invention is a semiconductor substrate cleaning method that contacts the semiconductor substrate cleaning composition with a substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film.
[0186] That is, the cleaning method of a semiconductor substrate according to the present invention is
[0187] Component (A): At least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base,
[0188] [MF n ] (n-k)-(a)
[0189] Component (B): A compound represented by the following general formula (b),
[0190] [MO m (OR) k-2m ] x (b)
[0191] (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 greater than or equal to k / 2; x is a positive integer; R is one selected from the group consisting of hydrogen atoms, alkali metals, and alkyl groups; and n is the coordination number of the fluoride ion for M.)
[0192] A semiconductor substrate cleaning composition comprising: component (C): an oxidizing agent, component (D): a tungsten corrosion inhibitor, component (E): an organic solvent, and component (F): water, wherein the component (E) comprises 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, and a substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film is contacted with the composition.
[0193] [Mathematical Formula 6]
[0194]
[0195] (In Equation (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.)
[0196] The cleaning method of the present invention is performed 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.
[0197] That is, by cleaning the substrate using the cleaning method of the present invention, titanium nitride can be removed, particularly while suppressing the corrosion of tungsten.
[0198] As a result, it becomes possible to clean and manufacture semiconductor substrates with miniaturized metal wiring, enabling high integration of semiconductor devices.
[0199] The temperature during cleaning in the cleaning method of the present invention is not particularly limited, but 20 to 80°C is preferred, and 25 to 70°C is more preferred. In addition, ultrasonic waves may be used during cleaning.
[0200] The cleaning time in the cleaning method of the present invention is not particularly limited, but is preferably 0.3 to 20 minutes, and more preferably 0.5 to 10 minutes.
[0201] In the cleaning method of the present invention, it is preferable to additionally rinse with a rinse solution containing water or alcohol, etc. after cleaning.
[0202] In the cleaning method of the present invention, the method of contacting the semiconductor substrate cleaning composition of the present invention with the substrate is not particularly limited. For example, a method of contacting the semiconductor substrate cleaning composition of the present invention with the substrate by means of dropping (single-wafer spin processing) or spraying (spray processing), or a method of immersing the substrate in the semiconductor substrate cleaning composition of the present invention may be used. In the present invention, any of these methods may be used, but the method of immersing the substrate in the semiconductor substrate cleaning composition of the present invention is preferred.
[0203] [Method for manufacturing a semiconductor substrate]
[0204] The method for manufacturing a semiconductor substrate according to the present invention is a method for manufacturing a semiconductor substrate comprising a process of contacting the semiconductor substrate cleaning composition with a substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film.
[0205] That is, the method for manufacturing a semiconductor substrate of the present invention is,
[0206] Component (A): At least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base,
[0207] [MF n ] (n-k)- (a)
[0208] Component (B): A compound represented by the following general formula (b),
[0209] [MO m (OR) k-2m ] x (b)
[0210] (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 greater than or equal to k / 2; x is a positive integer; R is one selected from the group consisting of hydrogen atoms, alkali metals, and alkyl groups; and n is the coordination number of the fluoride ion for M.)
[0211] A method for manufacturing a semiconductor substrate comprises 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) comprises 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, and a process of contacting a substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film.
[0212] [Mathematical Formula 7]
[0213]
[0214] (In Equation (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.)
[0215] A specific method for manufacturing a semiconductor substrate is described below.
[0216] 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, if necessary, a cap metal. Then, a photoresist pattern is formed by performing selective exposure and development on the photoresist. Subsequently, the photoresist pattern is transferred onto the hard mask by dry etching. After that, the photoresist pattern is removed, and dry etching is performed on the low dielectric constant interlayer insulating film and the barrier insulating film using the hard mask as an etching mask. Subsequently, a process of contacting the substrate with the semiconductor substrate cleaning composition, which is the above process, is carried out to obtain a semiconductor substrate having a desired metal wiring pattern.
[0217] 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.
[0218] As for the low dielectric constant interlayer insulating film, as described above, it 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.
[0219] A carbon-doped silicon dioxide film is preferred for the silicon dioxide film.
[0220] Among TEOS films, preferably, it is a PE-TEOS film (plasma TEOS film).
[0221] Silicon nitride, silicon carbide, silicon nitride carbide, etc. are used as barrier insulating films. Titanium or titanium nitride, etc. are used as hard masks, and in the present invention, titanium nitride is contained in the hard mask.
[0222] The metal wiring contains tungsten. The metal wiring may be solid tungsten or a tungsten alloy, but solid tungsten is preferred.
[0223] The process of contacting a semiconductor substrate cleaning composition, which is a process included in the present manufacturing method, with a substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film is preferably carried out under the same conditions as the cleaning method described in the aforementioned [method for cleaning a semiconductor substrate].
[0224] According to the method for manufacturing a semiconductor substrate of the present invention, since the semiconductor substrate cleaning composition is used to provide a process capable of removing unnecessary components while retaining necessary components, it is possible to manufacture a semiconductor substrate with finely miniaturized metal wiring, thereby enabling high integration of semiconductor devices.
[0225] Examples
[0226] The present invention will be explained in more detail below by way of examples, but the present invention is not limited to these examples.
[0227] Analysis Methods and Evaluation Methods
[0228] (1) Etching rate (ER)
[0229] (1-1) Etching rate (ER) of titanium nitride and low dielectric constant interlayer insulating film
[0230] A “titanium nitride film attached wafer” having a titanium nitride layer on a silicon wafer, and a “TEOS film attached wafer” having a plasma TEOS (PE-TEOS) layer, which is a type of low dielectric constant interlayer insulating film, on a silicon wafer were prepared.
[0231] Next, the film thickness was measured. The film thickness of the titanium nitride layer of the "titanium nitride film-attached wafer" was measured using a fluorescence X-ray device SEA1200VX (manufactured by SI Nano Technology Co., Ltd.). The film thickness of the PE-TEOS layer of the "TEOS film-attached wafer" was measured using an optical film thickness meter n&k1280 (manufactured by n&k Technology Co., Ltd.).
[0232] Next, the semiconductor substrate cleaning composition of the example and comparative example was adjusted to 60°C, and each film-attached 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 by the above measurement method.
[0233] 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 processing time.
[0234] Determination of titanium nitride etching rate
[0235] AA: 160 Å / min or higher
[0236] A: 120 Å / min or more and less than 160 Å / min
[0237] B: 80 Å / min or more and less than 120 Å / min
[0238] C: Less than 80 Å / min
[0239] Determination of TEOS etching rate
[0240] AA: Less than 1 Å / min
[0241] A: 1 Å / min or more and less than 2 Å / min
[0242] B: 2 Å / min or more and less than 3 Å / min
[0243] C: 3 Å / min or more
[0244] (1-2) Etching rate (ER) of tungsten
[0245] A “tungsten film-attached wafer” having a PVD-deposited tungsten layer on a silicon wafer was prepared.
[0246] Next, the semiconductor substrate cleaning compositions of the Examples and Comparative Examples were adjusted to 60°C, and a wafer with a tungsten film attached was immersed for 1 to 5 minutes. The cleaning solution ("composition used" in the following formula) after immersion was diluted 10 to 30 times with 1 mass% ammonia water, and the tungsten concentration was measured using an inductively coupled plasma emission spectrometer iCAP DUO-6300 (manufactured by Thermo Fisher). The tungsten concentration before dilution (W concentration) was calculated, and by substituting it into the following formula, the tungsten etching rate (ER) (ER of W) (Å / min) was calculated. Meanwhile, in the following formula, "19.30 g / cm² 3 ” is the density of tungsten, and “wafer area” is the area of the tungsten film on the wafer.
[0247] Determination of tungsten etching rate
[0248] AA: Less than 1 Å / min
[0249] A: 1 Å / min or more and less than 2 Å / min
[0250] B: 2 Å / min or more and less than 3 Å / min
[0251] C: 3 Å / min or more
[0252] [Mathematical Formula 8]
[0253]
[0254] (2) Evaluation of precipitation
[0255] Determination of the presence or absence of precipitation
[0256] A: No precipitation visible to the naked eye
[0257] C: Precipitation visible to the naked eye
[0258] <Composition for cleaning semiconductor substrates>
[0259] (Example 1)
[0260] A composition for cleaning a semiconductor substrate was obtained by combining hexafluorosilicic acid (component (A)), potassium silicate (component (B)), periodic acid (component (C)), benzalkonium chloride (component (D)), tetrahydrofuran (component (E)), and water (ultrapure water) to achieve the concentrations shown in Table 1.
[0261] (Examples 2–10 and Comparative Examples 1–6)
[0262] A composition for cleaning a semiconductor substrate was obtained in the same manner as in Example 1, except that the components and concentrations of Example 1 were changed to those shown in Table 1. In addition, component (E) was not incorporated in Comparative Examples 2 to 6.
[0263] Each semiconductor substrate cleaning composition was analyzed and evaluated using the method described in the above analysis 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.
[0264] [Table 1]
[0265]
Claims
Claim 1 Component (A): At least one selected from the group consisting of hydrofluoric acid, a salt of hydrofluoric acid, an acid having an anion represented by the following general formula (a) as a conjugate base, and a salt of an acid having an anion represented by the following general formula (a) as a conjugate base, [MF n ] (n-k)- (a) Component (B): 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 greater than or equal to k / 2; x is a positive integer; R is one selected from the group consisting of hydrogen atoms, alkali metals, and alkyl groups; and n is the coordination number of a fluoride ion for M.) A composition for cleaning a semiconductor substrate comprising: oxidizing agent, component (D): tungsten corrosion inhibitor, component (E): organic solvent, and component (F): water, wherein the component (E) comprises 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. [Mathematical Formula 1] (In Equation (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.) Claim 2 A composition for cleaning a semiconductor substrate according to claim 1, wherein the above component (A) comprises at least one selected from the group consisting of hydrofluoric acid, hexafluorosilicic acid, tetrafluoroboric acid, salt of hexafluorosilicic acid, and salt of tetrafluoroboric acid. Claim 3 A composition for cleaning a semiconductor substrate according to claim 1 or 2, wherein the component (B) comprises at least one selected from the group consisting of boric acid, a salt of boric acid, silicic acid, a salt of silicic acid, orthosilicic acid, and a salt of orthosilicic acid. Claim 4 A composition for cleaning a semiconductor substrate according to any one of claims 1 to 3, wherein the component (C) comprises at least one selected from the group consisting of vanadium oxide (V), vanadic acid (V), a salt of vanadic acid (V), iodic acid, a salt of iodic acid, orthoperiodic acid, and a salt of orthoperiodic acid. Claim 5 A composition for cleaning a semiconductor substrate according to any one of claims 1 to 4, wherein the component (D) comprises at least one selected from the group consisting of benzethonium chloride, benzalkonium chloride, alkylpyridinium chloride, and quaternary ammonium salt. Claim 6 A semiconductor substrate cleaning composition used to remove titanium nitride from a semiconductor substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film, in any one of claims 1 to 5. Claim 7 A semiconductor substrate cleaning composition according to any one of claims 1 to 6, wherein the content of the component (A) is 0.1 to 10 mass% with respect to the total amount of the semiconductor substrate cleaning composition. Claim 8 A semiconductor substrate cleaning composition according to any one of claims 1 to 7, wherein the content of the component (B) is 0.005 to 5 mass% with respect to the total amount of the semiconductor substrate cleaning composition. Claim 9 A semiconductor substrate cleaning composition according to any one of claims 1 to 8, wherein the content of the component (C) is 0.0005 to 1 mass% with respect to the total amount of the semiconductor substrate cleaning composition. Claim 10 A semiconductor substrate cleaning composition according to any one of claims 1 to 9, wherein the content of the component (D) is 0.0005 to 1 mass% with respect to the total amount of the semiconductor substrate cleaning composition. Claim 11 A semiconductor substrate cleaning composition according to any one of claims 1 to 10, wherein the content of the component (E) is 0.1 to 50 mass% with respect to the total amount of the semiconductor substrate cleaning composition. Claim 12 A composition for cleaning a semiconductor substrate 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 a conjugate base of an anion represented by the general formula (a) and a salt of an acid having a conjugate base of an anion represented by the general formula (a), and the ratio [(A) / (B)] of the content (mol) of the component (A) and the content (mol) of the component (B) is 1 to 100. Claim 13 A semiconductor substrate cleaning composition according to any one of claims 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, titanium nitride is removed at a removal rate of 80 Å / min or more, and the removal rate of tungsten is 3 Å / min or less. Claim 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, titanium nitride is removed 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. Claim 15 A method for cleaning a semiconductor substrate, wherein a semiconductor substrate cleaning composition described in any one of claims 1 to 14 is brought into contact with a substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film. Claim 16 A method for manufacturing a semiconductor substrate, comprising a process of contacting a semiconductor substrate cleaning composition described in any one of claims 1 to 14 with a substrate having titanium nitride, tungsten, and a low dielectric constant interlayer insulating film.