Cleaning solution, method for cleaning substrate, and method for manufacturing semiconductor element

Abstract

The cleaning solution is used for removing an etching residue containing an inorganic substance, and contains a compound (A) represented by general formula (a1) and at least one alkali selected from the group consisting of amines and ammonium compounds other than compound (A). In the general formula (a1),-R is-NH2 or-O-C (CH3) 3. The cleaning solution is a cleaning solution which has good dry etching residue removal performance, good metal wiring damage reduction performance and improved safety. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a cleaning liquid, a method for cleaning a substrate, and a method for manufacturing a semiconductor element.

[0002] This application claims priority based on Japanese Patent Application No. 2022-211681 filed in Japan on December 28, 2022, and incorporates its content herein. Background Art

[0003] In a wiring formation process, for example, a hard mask layer (HM layer) is formed on an interlayer insulating film on which a substrate, a metal wiring layer, and a silicon-based interlayer insulating film are sequentially stacked, and the HM layer is etched to form a model of a wiring pattern. The HM layer contains titanium nitride (TiN) or titanium oxide (TiOx).

[0004] Next, the etched HM layer is used as a mask to dry-etch the interlayer insulating film to produce a wiring pattern identical to the mask. Next, the HM layer is removed, and, for example, a copper metal film is buried in the interlayer insulating film having the shape of the wiring pattern by electroplating.

[0005] Inorganic residue-containing residues derived from the metal wiring layer and Ti-containing residues derived from the HM layer adhere to the element (substrate / metal wiring layer / interlayer insulating film / HM layer) after dry etching.

[0006] Conventionally, dry etching residues have been removed by a cleaning process.

[0007] As a cleaning liquid for removing dry etching residues, a cleaning liquid containing a peroxide as a residue remover has been proposed (for example, refer to Patent Document 1). Or a cleaning liquid containing hydroxylamine as a residue remover has been proposed.

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: International Publication No. 2016 / 076033 Summary of the Invention

[0011] Technical Problem to be Solved by the Invention

[0012] Ti-containing residues derived from the HM layer adhering to the element after dry etching are residues with high wet resistance and are difficult to remove by a cleaning process. However, in the case of using the cleaning liquid described in Patent Document 1, although it is effective for Ti-containing residues, in a substrate having a molybdenum wiring or a tungsten wiring, there is a problem that these wirings are damaged by the cleaning process.

[0013] In addition, in a cleaning liquid containing hydroxylamine, a substitute for the residue remover is desired from the viewpoint of the safety of hydroxylamine.

[0014] The present invention has been completed in view of the above circumstances, and the technical problem is to provide a cleaning liquid with good removability of dry etching residues and reduced damage to metal wirings and improved safety, as well as a method for cleaning a substrate using the cleaning liquid and a method for manufacturing a semiconductor device using the cleaning liquid.

[0015] Solution for Solving the Above Technical Problem

[0016] In order to solve the above technical problem, the present invention adopts the following constitution.

[0017] A first aspect of the present invention is a cleaning liquid for removing etching residues containing inorganic substances, containing a compound (A) represented by the following general formula (a1) and at least one base selected from the group consisting of amines and ammonium compounds other than the compound (A).

[0018] [Chemical Formula 1]

[0019]

[0020] [In the formula, -R is -NH2 or -O-C(CH3)3.]

[0021] A second aspect of the present invention is a method for cleaning a substrate, including: step (P1) of cleaning a substrate with the etching residues containing inorganic substances using the cleaning liquid of the first aspect.

[0022] A third aspect of the present invention is a method for manufacturing a semiconductor device, including: step (P1) of cleaning a substrate with the etching residues containing inorganic substances using the cleaning liquid of the first aspect.

[0023] Advantages of the Invention

[0024] According to the present invention, it is possible to provide a cleaning liquid with good removability of dry etching residues and reduced damage to metal wirings and improved safety, as well as a method for cleaning a substrate using the cleaning liquid and a method for manufacturing a semiconductor device using the cleaning liquid. Description of the Drawings

[0025] Figure 1 It is a cross-sectional view showing an example of an element after dry etching to be cleaned. Detailed Description

[0026] (First Aspect: Cleaning Liquid)

[0027] The cleaning liquid of the first aspect of the present invention is a cleaning liquid for removing etching residues containing inorganic substances.

[0028] The "inorganic substances" referred to herein mean compounds containing metal atoms, such as metal atoms, metal oxides, metal nitrides, metal chlorides, metal fluorides, etc. Examples of metal atoms include Ti, Ta, Cu, Co, Ru, Al, W, Mo, Au, Ag, Fe, Ni, Si, etc. Examples of metal oxides include TiOx, TaOx, CuOx, CoOx, RuOx, AlOx, WOx, MoOx, AuOx, AgOx, FeOx, NiOx, SiOx, etc. Examples of metal nitrides include TiNx, TaNx, CuNx, CoNx, RuNx, AlNx, WNx, MoNx, AuNx, AgNx, FeNx, NiNx, SiNx, etc. Examples of metal chlorides include TiClx, TaClx, CuClx, CoClx, RuClx, AlClx, WClx, MoClx, AuClx, AgClx, FeClx, NiClx, SiClx, etc. Examples of metal fluorides include TiFx, TaFx, CuFx, CoFx, RuFx, AlFx, WFx, MoFx, AuFx, AgFx, FeFx, NiFx, SiFx, etc.

[0029] Examples of etching residues, especially dry etching residues, include Ti-containing residues derived from the HM layer and inorganic substance-containing residues derived from the metal wiring layer that adhere during the wiring process. Dry etching residues deteriorate the yield and electrical characteristics of semiconductors, so they need to be removed before the next process. The cleaning liquid of this solution is suitable for cleaning a substrate after dry etching through the wiring process.

[0030] One embodiment of the cleaning liquid of this solution contains a compound (A) represented by the following general formula (a1) and at least one base selected from the group consisting of amines and ammonium compounds other than the compound (A).

[0031] [Chemical formula 2]

[0032]

[0033] [In the formula, -R is -NH2 or -O-C(CH3)3.]

[0034] <Compound (A)>

[0035] The cleaning liquid of this embodiment contains a compound (A) represented by the general formula (a1) (hereinafter also referred to as the "(A) component"). In the cleaning liquid, the (A) component is used as a residue remover.

[0036] The (A) component is safer than hydroxylamine. In addition, the (A) component does not damage the metal wiring during the cleaning process.

[0037] In the formula (a1), when -R is -NH2, the component (A) is hydroxyurea.

[0038] In the formula (a1), when -R is -O-C(CH3)3, the component (A) is N-(tert-butoxycarbonyl)hydroxylamine.

[0039] In the cleaning liquid of the present embodiment, the component (A) can be used alone as 1 kind, or 2 kinds can be used in combination.

[0040] The content of the component (A) in the cleaning liquid of the present embodiment is not particularly limited, and is preferably 0.02% by mass or more and 20% by mass or less, more preferably 0.2% by mass or more and 18% by mass or less, and further preferably 0.3% by mass or more and 15% by mass or less, based on the total mass of the cleaning liquid.

[0041] If the content of the component (A) is at least the lower limit value of the above preferred range, the removability of dry etching residues is further improved in the cleaning process. On the other hand, if the content of the component (A) is at most the upper limit value of the preferred range, the damage to the metal wiring is further suppressed.

[0042] <Base>

[0043] The cleaning liquid of the present embodiment contains at least one base selected from the group consisting of amines and ammonium compounds other than the compound (A). By containing this base, the pH of the cleaning liquid can be increased, and the residue removal effect of the component (A) can be easily demonstrated.

[0044] Examples of the amine other than the compound (A) in the base include ammonia (NH3), primary monoamines, secondary monoamines, tertiary monoamines, alkanolamines, secondary cyclic amines, tertiary cyclic amines, quaternary cyclic amines, diamines, and polyamines.

[0045] Examples of the primary monoamines include alkylamines such as methylamine, ethylamine, propylamine, n-butylamine, isopropylamine, and tert-butylamine; cycloalkylamines such as cyclopentylamine, cyclohexylamine, and cyclohexanemethylamine; and alkoxyamines such as methoxyethylamine, methoxypropylamine, methoxybutylamine, ethoxypropylamine, and propoxypropylamine.

[0046] Examples of the secondary monoamines include alkylamines such as dimethylamine, diethylamine, methylethylamine, dipropylamine, diisopropylamine, dibutylamine, diisobutylamine, and butylmethylamine; cycloalkylamines such as N,N-dicyclohexylamine and N-cyclopentylcyclohexylamine; and alkoxyamines such as methoxy(methylamine) and N-(2-methoxyethyl)ethylamine.

[0047] Examples of the tertiary monoamines include alkylamines such as trimethylamine, triethylamine, tripropylamine, tributylamine, triisobutylamine, dimethylethylamine, dimethylpropylamine, allyldiethylamine, dimethyl-n-butylamine, and diethylisopropylamine; and cycloalkylamines such as tricyclopentylamine and tricyclohexylamine.

[0048] Examples of the alkanolamine include monoethanolamine, diethanolamine, triethanolamine, etc.

[0049] Examples of the secondary cyclic amine include piperidines (compounds having a piperidine skeleton), pyrrolidines (compounds having a pyrrolidine skeleton), morpholines (compounds having a morpholine skeleton), etc. Examples of the piperidines as the secondary cyclic amine include piperidine, 2-methylpiperidine, 3-methylpiperidine, 4-methylpiperidine, 2,6-dimethylpiperidine, 3,5-dimethylpiperidine, etc. Examples of the pyrrolidines include pyrrolidine, 2-methylpyrrolidine, 3-methylpyrrolidine, etc. Examples of the morpholines include morpholine, 2-methylmorpholine, 3-methylmorpholine, etc.

[0050] Examples of the tertiary cyclic amine include piperidines, pyrrolidines, morpholines, etc. Examples of the piperidines include N-methylpiperidine, etc. Examples of the pyrrolidines include N-methylpyrrolidine, etc. Examples of the morpholines include N-methylmorpholine, etc.

[0051] Examples of the quaternary cyclic amine include fluorides, chlorides, bromides, iodides, sulfates, bisulfates, acetates, etc. of piperidines, pyrrolidines, morpholines, etc.

[0052] The diamine can be any one of primary diamines, secondary diamines and tertiary diamines. Examples of the primary diamines include 2-(2-aminoethylamino)ethanol, ethylenediamine, butane-1,4-diamine, 1,3-propanediamine, 1,6-hexanediamine, pentane-1,5-diamine, etc. Examples of the secondary diamines include 2-methylpiperazine, 2,3-dimethylpiperazine, 2,5-dimethylpiperazine, N,N'-dimethylethylenediamine, N,N'-dimethylpropanediamine, N,N'-diethylethylenediamine, N,N'-diethylpropanediamine, N,N'-diisopropylethylenediamine, etc. Examples of the tertiary diamines include 4-dimethylaminopyridine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetraethylethylenediamine, N,N,N',N'-tetramethyl-1,3-diaminopropane, N,N,N',N'-tetramethyl-1,3-diaminobutane, N,N,N',N'-tetramethyl-1,4-diaminobutane, N,N,N',N'-tetramethylbenzene-1,2-diamine, 1,2-dipiperidinoethane, etc.

[0053] A polyamine is a compound containing three or more amino groups, preferably a triamine. The polyamine may contain any one of a primary amino group, a secondary amino group, and a tertiary amino group. Examples of the polyamine include spermine, spermidine, 3,3'-iminobis(propylamine), N,N-bis(3-aminopropyl)methylamine, N,N-bis(3-aminopropyl)butylamine, N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine, diethylenetriamine, N,N,N',N",N"-pentamethyldiethylenetriamine, N,N,N',N",N"-pentamethyldipropylenetriamine, tris[2-(dimethylamino)ethyl]amine, 2-aminomethylpyrimidine, 1,4-bis(3-aminopropyl)piperazine, 1-aminocyclopentylpiperazine, 1-(2-pyridyl)piperazine, and the like.

[0054] Examples of the ammonium compound in the base include hydroxides of quaternary amines and quaternary ammonium salts other than hydroxides.

[0055] Examples of the hydroxide of the quaternary amine include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, dimethylbis(2-hydroxyethyl)ammonium hydroxide, tetrabutylammonium hydroxide, tetraamylammonium hydroxide, tris(2-hydroxyethyl)methylammonium hydroxide, choline, dimethyldiethylammonium hydroxide, tetraethanolammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, benzyltributylammonium hydroxide, and the like.

[0056] Examples of the quaternary ammonium salt other than the hydroxide include fluoride, chloride, bromide, iodide, sulfate, bisulfate, acetate, and the like of the quaternary ammonium. Specific examples of the quaternary ammonium salt include tetraethylammonium chloride, tetramethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetraamylammonium chloride, tetraethylammonium bromide, tetramethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetraamylammonium bromide, tetraethylammonium fluoride, tetramethylammonium fluoride, tetrapropylammonium fluoride, tetrabutylammonium fluoride, tetraamylammonium fluoride, tetraethylammonium iodide, tetramethylammonium iodide, tetrapropylammonium iodide, tetrabutylammonium iodide, tetraamylammonium iodide, tetraethylammonium bisulfate, tetramethylammonium bisulfate, tetrapropylammonium bisulfate, tetrabutylammonium bisulfate, and the like.

[0057] In the cleaning liquid of the present embodiment, the base may be used alone in one kind or two or more kinds may be used in combination.

[0058] Among the bases, at least one selected from the group consisting of ammonia, hydroxides of quaternary amines, alkanolamines, and triamines is preferably used, and at least one selected from the group consisting of ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide, alkanolamines, and triamines is more preferably used.

[0059] From the viewpoint of the removability of the dry etching residue, as the base, at least one selected from the group consisting of ammonia and triamines is preferably used, and ammonia is particularly preferably used.

[0060] The content of the alkali in the cleaning liquid of the present embodiment is not particularly limited, and is preferably 0.003% by mass or more and 15% by mass or less, more preferably 0.03% by mass or more and 13% by mass or less, further preferably 0.2% by mass or more and 12% by mass or less, and particularly preferably 0.5% by mass or more and 10% by mass or less, relative to the total mass of the cleaning liquid.

[0061] If the content of the alkali is at least the lower limit value of the above preferred range, the removability of the dry etching residue is further improved during the cleaning process. On the other hand, if the content of the alkali is at most the upper limit value of the above preferred range, the combined effect with the component (A) is easily obtained.

[0062] In the cleaning liquid of the present embodiment, the content of the alkali is preferably 15 to 5000 parts by mass, more preferably 20 to 2500 parts by mass, and further preferably 50 to 1000 parts by mass, relative to 100 parts by mass of the compound (A).

[0063] If the content of the alkali relative to 100 parts by mass of the compound (A) is at least the lower limit value of the above preferred range, the removability of the dry etching residue and the reduction of damage to the metal wiring are easily improved during the cleaning process. On the other hand, if the content of the alkali is at most the upper limit value of the above preferred range, the combined effect with the component (A) is easily obtained.

[0064] <Solvent>

[0065] The cleaning liquid of the present embodiment contains water as a solvent.

[0066] The water may also contain trace components inevitably mixed in. The water that can be used in the cleaning liquid of the present embodiment is preferably water subjected to purification treatment such as distilled water, ion-exchanged water, and ultrapure water, and more preferably ultrapure water commonly used in semiconductor manufacturing.

[0067] In the cleaning liquid of the present embodiment, water can be blended so that the total content of the component (A), the component (B), and any components to be blended as required is 100% by mass, that is, the content of water can be the remaining part.

[0068] In addition to water, the cleaning liquid of the present embodiment may also contain an organic solvent described later as a solvent.

[0069] <Optional components>

[0070] The cleaning liquid of the present embodiment may also contain optional components in addition to the above components (A) and (B). Examples of the optional components include corrosion inhibitors, buffers, organic solvents, surfactants, pH adjusters, and the like.

[0071] <<Corrosion inhibitor>>

[0072] The cleaning liquid of the present embodiment may also contain a corrosion inhibitor.

[0073] Examples of the corrosion inhibitor include compounds containing a nitrogen-containing heterocyclic ring such as a triazole ring, an imidazole ring, a pyridine ring, a phenanthroline ring, a tetrazole ring, a pyrazole ring, a pyrimidine ring, and a purine ring.

[0074] 《Buffer》

[0075] The cleaning liquid of the present embodiment may also contain a buffer. A buffer is a compound having the function of suppressing the pH change of the cleaning liquid.

[0076] The buffer is not particularly limited as long as it is a compound having pH buffering ability. For example, a compound having a pKa of 6 to 11 can be used as the buffer.

[0077] Examples of the buffer include Good's buffers. Examples of Good's buffers include 2-cyclohexylaminoethanesulfonic acid (CHES), 3-cyclohexylaminopropanesulfonic acid (CAPS), N-tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid (TAPS), 4-(cyclohexylamino)-1-butanesulfonic acid (CABS), tris(hydroxymethyl)methylglycine (tricine), N,N-bis(2-hydroxyethyl)glycine (bicine), 2-morpholinoethanesulfonic acid monohydrate (MES), bis(2-hydroxyethyl)aminotris(hydroxymethyl)methane (Bis-Tris), N-(2-acetamido)iminodiacetic acid (ADA), piperazine-1,4-bis(2-ethanesulfonic acid) (PIPES), N-(2-acetamido)-2-aminoethanesulfonic acid (ACES), 2-hydroxy-3-morpholinopropanesulfonic acid (MOPSO), N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES), 3-morpholinopropanesulfonic acid (MOPS), N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES), 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid (HEPES), 3-[N-tris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonic acid (TAPSO), piperazine-1,4-bis(2-hydroxypropanesulfonic acid) (POPSO), 4-(2-hydroxyethyl)piperazine-1-(2-hydroxypropane-3-sulfonic acid) (HEPSO), 4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid (EPPS), and the like.

[0078] The cleaning liquid of the present embodiment may not contain a buffer, and may not contain one or more of the above compounds exemplified as specific examples of the buffer.

[0079] 《Organic Solvent》

[0080] Within the scope not impairing the effects of the present invention, the cleaning liquid of the present embodiment may contain an organic solvent. The organic solvent is preferably a water-soluble organic solvent. By containing an organic solvent, it is easy to remove organic residues such as polymers.

[0081] Examples of the water-soluble organic solvent include alcohols such as isopropyl alcohol, ethanol, ethylene glycol, propylene glycol, glycerin, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, dipropylene glycol, furfuryl alcohol, 2-methyl-2,4-pentanediol, 3-methoxy-3-methyl-1-butanol; dimethyl sulfoxide; ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, propylene glycol dimethyl ether; morpholines such as N-methylmorpholine N-oxide.

[0082] The organic solvent may be used alone or in combination of two or more.

[0083] When the cleaning liquid of the present embodiment contains an organic solvent, the content range of the organic solvent is preferably 0.05 to 50% by mass, more preferably 0.1 to 30% by mass, further preferably 0.1 to 20% by mass, and particularly preferably 0.1 to 10% by mass, based on the total amount of water and the organic solvent.

[0084] The cleaning liquid of the present embodiment may not contain an organic solvent or a water-soluble organic solvent, or may not contain one or more of the above compounds exemplified as specific examples of the water-soluble organic solvent.

[0085] "Surfactant"

[0086] For purposes such as adjusting the wettability of the cleaning liquid with respect to the substrate, the cleaning liquid of the present embodiment may also contain a surfactant. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants.

[0087] Examples of the nonionic surfactant include polyalkylene oxide alkyl phenyl ether surfactants, polyalkylene oxide alkyl ether surfactants, block polymer surfactants composed of polyethylene oxide and polypropylene oxide, polyoxyalkylene stilbenated phenyl ether surfactants, polyalkylene tribenzyl benzene ether surfactants, acetylene polyalkylene oxide surfactants, etc.

[0088] Examples of the anionic surfactant include alkyl sulfonic acid, alkyl benzene sulfonic acid, alkyl naphthalene sulfonic acid, alkyl diphenyl ether sulfonic acid, fatty acid amide sulfonic acid, polyoxyethylene alkyl ether carboxylic acid, polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl ether propionic acid, alkyl phosphonic acid, salts of fatty acids, etc. Examples of the "salt" include ammonium salt, sodium salt, potassium salt, tetramethylammonium salt, etc.

[0089] As cationic surfactants, for example, alkylpyridinium surfactants, quaternary ammonium salt surfactants, etc. can be cited.

[0090] As amphoteric surfactants, for example, betaine-type surfactants, amino acid-type surfactants, imidazoline-type surfactants, amine oxide-type surfactants, etc. can be cited.

[0091] These surfactants can generally be obtained commercially. The surfactant can be used alone or two or more kinds can be used in combination.

[0092] When the cleaning liquid in the present embodiment contains a surfactant, the content of the surfactant is not particularly limited. For example, it is preferably 0.0001% by mass to 5% by mass, more preferably 0.0002% by mass to 3% by mass, further preferably 0.002% by mass to 1% by mass, and particularly preferably 0.002% by mass to 0.2% by mass relative to the total mass of the cleaning liquid.

[0093] The cleaning liquid of the present embodiment may not contain one or more selected from the group consisting of nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants, and may not contain one or more of the above compounds exemplified as these surfactants. The cleaning liquid of the present embodiment may also not contain a surfactant.

[0094] 《pH Adjusting Agent》

[0095] In order to adjust to a desired pH, the cleaning liquid of the present embodiment may also contain a pH adjusting agent. As the pH adjusting agent, inorganic acids, organic acids, organic basic compounds, and inorganic basic compounds can be appropriately used.

[0096] 《Impurities, etc.》

[0097] The cleaning liquid of the present embodiment may contain, for example, metal impurities, and the metal impurities contain metal atoms such as Fe atoms, Cr atoms, Ni atoms, Zn atoms, Ca atoms, or Pb atoms.

[0098] The total content of the above metal atoms in the cleaning liquid of the present embodiment is preferably 100 mass ppt or less relative to the total mass of the cleaning liquid. The lower the lower limit value of the total content of the metal atoms, the more preferable. For example, 0.001 mass ppt or more can be cited. The total content of the metal atoms can be, for example, 0.001 mass ppt to 100 mass ppt. By making the total content of the metal atoms below the above-mentioned preferred upper limit value, the defect inhibition and residue inhibition of the cleaning liquid are improved. It is considered that by setting the total content of the metal atoms above the above-mentioned preferred lower limit value, the metal atoms are not likely to exist in a free state in the system and are not likely to have an adverse effect on the overall manufacturing yield of the object to be cleaned.

[0099] The content of metal impurities can be adjusted, for example, by purification treatment such as filtration. The purification treatment such as filtration can be performed on a part or all of the raw materials before preparing the cleaning liquid, or can be performed after preparing the cleaning liquid.

[0100] The cleaning liquid of the present embodiment may contain, for example, impurities derived from organic substances (organic impurities). The total content of the above organic impurities in the cleaning liquid of the present embodiment is preferably 5000 mass ppm or less. The lower the lower limit of the content of the organic impurities, the more preferable it is. For example, 0.1 mass ppm or more can be cited. As the total content of the organic impurities, for example, 0.1 mass ppm to 5000 mass ppm can be cited.

[0101] In the cleaning liquid of the present embodiment, for example, a counted object having a size that can be counted by a light scattering type in-liquid particle counter may also be contained. The size of the counted object is, for example, 0.04 μm or more. The number of counted objects in the cleaning liquid of the present embodiment is, for example, 1,000 or less per 1 mL of the cleaning liquid, and the lower limit value is, for example, 1 or more. It is considered that by making the number of counted objects in the cleaning liquid within the above range, the metal corrosion inhibition effect brought by the cleaning liquid is improved.

[0102] The above organic impurities and / or counted objects can be added to the cleaning liquid, or can be inevitably mixed into the cleaning liquid during the manufacturing process of the cleaning liquid. As a case of being inevitably mixed during the manufacturing process of the cleaning liquid, for example, cases where organic impurities are contained in raw materials (such as organic solvents) used in the manufacture of the cleaning liquid, and cases where they are mixed in from the external environment during the manufacturing process of the cleaning liquid (such as contamination), etc. are cited, but are not limited to the above cases.

[0103] In the case of adding a counted object to the cleaning liquid, the existence ratio can also be adjusted according to each specific size in consideration of the surface roughness of the object to be cleaned, etc.

[0104] <pH of the cleaning liquid>

[0105] Regarding the pH of the cleaning liquid of the present embodiment, the pH measured at 23 °C is preferably 8.0 or more, and more preferably 8.0 or more and less than 14.0.

[0106] If the pH of the cleaning liquid is at least the lower limit value of the above preferred range, the removability of dry etching residues is easily improved during the cleaning process.

[0107] The pH of the cleaning liquid is a value measured by a pH meter at 23 °C under normal pressure (1 atmosphere).

[0108] As the cleaning liquid of the present embodiment, for example, the following embodiments (1-1) and (1-2) can be preferably cited.

[0109] Embodiment (1-1): A cleaning solution containing hydroxyurea (in the case where -R in the formula (a1) is -NH2), at least one base selected from the group consisting of amines and ammonium compounds other than the compound (A), and water.

[0110] Embodiment (1-2): A cleaning solution containing N-(tert-butoxycarbonyl)hydroxylamine (in the case where -R in the formula (a1) is -O-C(CH3)3), at least one base selected from the group consisting of amines and ammonium compounds other than the compound (A), and water.

[0111] Regarding Embodiment (1-1):

[0112] The cleaning solution of Embodiment (1-1) contains hydroxyurea, at least one base selected from the group consisting of amines and ammonium compounds other than the compound (A), and water as the remainder, and may contain optional components as needed.

[0113] Among the bases, at least one selected from the group consisting of ammonia, hydroxides of quaternary amines, alkanolamines, and triamines is preferably used, and at least one selected from the group consisting of ammonia, tetraethylammonium hydroxide, monoethanolamine, and diethylenetriamine is more preferably used.

[0114] The content of hydroxyurea in the cleaning solution of Embodiment (1-1) is preferably 0.02% by mass or more and 20% by mass or less, more preferably 0.2% by mass or more and 15% by mass or less, and further preferably 0.5% by mass or more and 10% by mass or less, relative to the total mass of the cleaning solution.

[0115] The content of the base in the cleaning solution of Embodiment (1-1) is preferably 0.003% by mass or more and 15% by mass or less, more preferably 0.03% by mass or more and 13% by mass or less, further preferably 0.2% by mass or more and 12% by mass or less, and particularly preferably 0.5% by mass or more and 10% by mass or less, relative to the total mass of the cleaning solution.

[0116] In the cleaning solution of Embodiment (1-1), the content of the base is preferably 15 to 5000 parts by mass, more preferably 20 to 2500 parts by mass, and further preferably 50 to 1000 parts by mass, relative to 100 parts by mass of hydroxyurea.

[0117] Regarding the pH of the cleaning solution of Embodiment (1-1), the pH measured at 23°C is preferably 9.0 or more, more preferably pH 9.5 or more and less than pH 14.0, and further preferably pH 10.0 or more and pH 13.6 or less.

[0118] Embodiment (1-2):

[0119] The cleaning liquid of the embodiment (1-2) contains N-(tert-butoxycarbonyl)hydroxylamine, at least one base selected from the group consisting of amines and ammonium compounds other than the compound (A), and water as the remainder, and may contain optional components as needed.

[0120] Among the bases, it is preferable to use at least one selected from the group consisting of ammonia, hydroxides of quaternary amines, alkanolamines, and triamines, more preferably to use at least one selected from the group consisting of ammonia, hydroxides of quaternary amines, and alkanolamines, and still more preferably to use at least one selected from the group consisting of ammonia, tetraethylammonium hydroxide, and monoethanolamine.

[0121] The content of N-(tert-butoxycarbonyl)hydroxylamine in the cleaning liquid of the embodiment (1-2) is preferably 0.02% by mass or more and 15% by mass or less, more preferably 0.3% by mass or more and 10% by mass or less, and still more preferably 0.4% by mass or more and 5% by mass or less, relative to the total mass of the cleaning liquid.

[0122] The content of the base in the cleaning liquid of the embodiment (1-2) is preferably 0.003% by mass or more and 15% by mass or less, more preferably 0.03% by mass or more and 13% by mass or less, still more preferably 0.2% by mass or more and 12% by mass or less, and particularly preferably 0.5% by mass or more and 10% by mass or less, relative to the total mass of the cleaning liquid.

[0123] In the cleaning liquid of the embodiment (1-2), the content of the base is preferably 15 to 5000 parts by mass, more preferably 20 to 2500 parts by mass, and still more preferably 50 to 1000 parts by mass, relative to 100 parts by mass of N-(tert-butoxycarbonyl)hydroxylamine.

[0124] Regarding the pH of the cleaning liquid of the embodiment (1-2), the pH measured at 23°C is preferably 8.0 or more, more preferably 8.5 or more and less than 14.0, and still more preferably 9.0 or more and 13.8 or less.

[0125] The method for storing the cleaning liquid of the present embodiment is not particularly limited, and conventionally known containers can also be used. In order to ensure the stability of the cleaning liquid, the void ratio in the container and / or the type of gas filling the void part may be appropriately set when storing in the container. For example, the void ratio in the storage container may be about 0.01 to 30% by volume.

[0126] The cleaning liquid of the present embodiment can be used, for example, in the following (Second Scheme: Substrate Cleaning Method).

[0127] According to the cleaning liquid of the present embodiment described above, by containing the compound (A) represented by the general formula (a1) and at least one base selected from the group consisting of amines and ammonium compounds other than the compound (A), in a component with an etching residue containing an inorganic substance, it is possible to cleanly remove the etching residue derived from the HM layer while protecting the metal wiring layer. Therefore, it can be suitably used for cleaning a substrate (substrate, component) after dry etching by a wiring process.

[0128] In addition, in the cleaning liquid of the present embodiment, since the compound (A) is used as a residue remover, the safety is improved compared to hydroxylamine commonly used in the past.

[0129] In addition, hydroxylamine is an explosive compound, belongs to Class 5 dangerous substances (self-reactive substances) in the Fire Service Act, and is a substance designated as a highly toxic substance by the Poisonous and Extremely Toxic Substances Control Act.

[0130] (Second aspect: Method for cleaning a substrate)

[0131] The method for cleaning a substrate according to the second aspect of the present invention includes: step (P1) of cleaning a substrate with an etching residue containing an inorganic substance using the cleaning liquid of the first aspect.

[0132] In the cleaning method of this aspect, the substrate with an etching residue as the object to be cleaned includes a substrate alone and a component having a substrate.

[0133] The component may be, for example, a component after dry etching of a metal wiring layer by a damascene process. In addition, the component may be a component in which a metal wiring layer is exposed after dry etching of a Si-containing layer (for example, a Si interlayer insulating film) by a wiring process. In addition, the component may be a substrate in which a metal wiring layer is exposed after a CMP process in a wiring process.

[0134] The metal wiring layer preferably contains at least one metal selected from the group consisting of molybdenum, tungsten, ruthenium, copper, iron, nickel, aluminum, lead, zinc, tin, tantalum, magnesium, cobalt, bismuth, cadmium, titanium, zirconium, antimony, manganese, beryllium, chromium, germanium, vanadium, gallium, hafnium, indium, niobium, rhenium, and thallium.

[0135] Hereinafter, an embodiment of the method for cleaning a substrate of this aspect will be described with reference to the drawings.

[0136] Figure 1 An example of a dry-etched component (substrate / metal wiring layer / interlayer insulating film / HM layer) as the object to be cleaned is shown.

[0137] In Figure 1In the shown component 100, a substrate 10, a metal wiring layer 20, an etch stop layer 30, and an interlayer insulating film 40 are stacked in sequence, and a hard mask layer (HM layer) 50 is formed on the interlayer insulating film 40.

[0138] The component 100 is a component after dry etching through a wiring process, that is, a component in a state where dry etching of the interlayer insulating film 40 has been performed using the HM layer 50 of a model in which a wiring pattern is formed by dry etching as a mask. Dry etching residues 60 adhere to the side surfaces of the HM layer 50 and the interlayer insulating film 40.

[0139] In the space between the interlayer insulating films 40 in the shape of the wiring pattern, the metal wiring layer 20 is exposed, and dry etching residues 60 also adhere thereto.

[0140] The substrate 10 is made of materials such as silicon, amorphous silicon, and glass.

[0141] The metal wiring layer 20 is a wiring layer made of metals such as molybdenum, tungsten, ruthenium, copper, iron, nickel, aluminum, lead, zinc, tin, tantalum, magnesium, cobalt, bismuth, cadmium, titanium, zirconium, antimony, manganese, beryllium, chromium, germanium, vanadium, gallium, hafnium, indium, niobium, rhenium, and thallium.

[0142] The interlayer insulating film 40 is made of silicon-based materials such as SiO2, SiN, and SiOC.

[0143] The HM layer 50 is made of titanium-based materials such as titanium nitride (TiN) and titanium oxide (TiOx).

[0144] The dry etching residues 60 are mainly Ti-containing residues containing titanium-based materials derived from the HM layer 50.

[0145] [Process (P1) for cleaning]

[0146] This process (P1) is a process of cleaning the component 100 after dry etching through a wiring process using the cleaning liquid of the first solution.

[0147] The cleaning method is not particularly limited, and a known cleaning method can be used.

[0148] When bringing the cleaning liquid into contact with the component 100 to be cleaned, the cleaning liquid can be diluted to 2 to 2000 times to obtain a diluted liquid, and then the operation of cleaning using the diluted liquid can be performed.

[0149] As the cleaning operation, for example, a method of continuously coating the cleaning liquid on the component 100 rotating at a certain speed (spin coating method), a method of immersing the component 100 in the cleaning liquid for a certain time (immersion method), a method of spraying the cleaning liquid onto the surface of the component 100 (spray method), etc. can be cited.

[0150] The temperature for the cleaning treatment is not particularly limited. The cleaning treatment is preferably carried out under the conditions of 10 to 80 °C, and can be 20 to 75 °C, or can be 40 to 70 °C.

[0151] By increasing the temperature of the cleaning liquid, the removability of the etching residue is improved. However, considering minimizing the change in the composition of the cleaning liquid, as well as workability, safety, cost, etc., the temperature of the cleaning liquid can be appropriately selected.

[0152] The cleaning time can be appropriately selected to be sufficient to remove the etching residue, impurities, etc. attached to the surface of the element 100. As the cleaning time, for example, it is 10 seconds to 30 minutes, can be 20 seconds to 15 minutes, can also be 30 seconds to 10 minutes, and can further be 30 seconds to 5 minutes.

[0153] According to the cleaning method of the present embodiment described above, since the cleaning is performed using the cleaning liquid of the first aspect, in the element 100 with the dry etching residue 60, damage to the metal wiring layer 20 can be suppressed, and the dry etching residue 60 derived from the HM layer 50 can be cleaned and removed well. In addition, according to the cleaning method of the present embodiment, damage to the interlayer insulating film 40 can also be suppressed.

[0154] In addition, in the cleaning liquid, since the compound (A) is used as the residue remover, compared with the conventionally commonly used hydroxylamine, the manufacturing of semiconductor elements, etc. can be carried out more safely.

[0155] (Third aspect: Manufacturing method of semiconductor element)

[0156] The manufacturing method of the semiconductor element according to the third aspect of the present invention includes a step (P1) of cleaning a substrate with the etching residue containing inorganic substances using the cleaning liquid of the first aspect.

[0157] As an embodiment of the manufacturing method of the semiconductor element, a manufacturing method including the step (P1) and any step can be exemplified.

[0158] In the manufacturing method of the present embodiment, the step (P1) can be carried out in the same manner as the method described in [step (P1) of performing cleaning] in the above (Second aspect: Cleaning method of substrate).

[0159] As an arbitrary process, before the process (P1), a hard mask layer etching process, a dry etching process of a wiring layer, a contact etching process, etc. can be exemplified. Further, as an arbitrary process, known processes performed in manufacturing semiconductor elements can be exemplified, such as capacitor formation, channel formation, High-K / metal gate formation, metal wiring, gate structure, source structure, drain structure, insulating layer, ferromagnetic layer, and non-magnetic layer, etc. (layer formation, etching other than the above etching process, chemical mechanical polishing, modification, etc.), resist film formation process, exposure process, development process, heat treatment process, inspection process, etc.

[0160] According to the manufacturing method of the semiconductor element of the present embodiment described above, since it includes the process (P1) of cleaning a substrate with an etching residue containing an inorganic substance using the cleaning liquid of the first aspect, damage to the metal wiring can be suppressed, and the etching residue can be removed well. Thereby, improvement in the electrical characteristics of the manufactured semiconductor element is achieved.

[0161] Examples

[0162] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited by these examples.

[0163] The components used in the examples and comparative examples are shown below.

[0164] · Residue remover

[0165] (A)-1: Hydroxyurea

[0166] (A)-2: N-Boc-HA (N-(tert-butoxycarbonyl)hydroxylamine)

[0167] (A)-3: Hydroxylamine

[0168] (A)-4: Hydrogen peroxide

[0169] [Chemical formula 3]

[0170]

[0171] · Base

[0172] (B)-1: Ammonia

[0173] (B)-2: Tetraethylammonium hydroxide

[0174] (B)-3: Monoethanolamine

[0175] (B)-4: Diethylenetriamine

[0176] [Chemical formula 4]

[0177]

[0178] ·pH regulator

[0179] (C)-1: Citric acid

[0180] ·Solvent

[0181] (S)-1: Water

[0182] (S)-2: Glycerol

[0183] (Preparation of cleaning solution)

[0184] (Examples 1 to 13, Comparative Examples 1 to 4; Examples 14 to 25, Comparative Examples 5 to 8)

[0185] Prepare the cleaning solutions for each example using the respective components shown in Tables 1 to 2.

[0186] In Tables 1 to 2, each abbreviation has the above-mentioned meaning. The values in [] represent the proportion (mass%) of the content of each component relative to the total mass of the cleaning solution.

[0187] [pH of cleaning solution]

[0188] Measure the pH of the cleaning solution at a temperature of 23°C using a pH meter (portable pH meter D-73S, manufactured by Horiba, Ltd.). The results are shown in Tables 1 to 2 as "pH (23°C)".

[0189] (Evaluation)

[0190] For the cleaning solutions of each example, evaluate the removability of etching residues and the reduction of metal damage using the etching rate as an index as described below.

[0191] [Measurement of etching rate]

[0192] As the substrate, use a substrate on which a titanium nitride (TiN) film with a thickness of 50 nm, a tungsten (W) film with a thickness of 100 nm, and a molybdenum (Mo) film with a thickness of 50 nm are respectively formed by PVD method on a 12-inch silicon substrate.

[0193] Cut the substrate after film formation into 2 cm × 2 cm to produce wafer specimens.

[0194] Add 100 mL of the cleaning solution for each example to a 200 mL beaker, heat to the specified treatment temperature shown in the table, and immerse the cut wafer specimens in the cleaning solution. During the immersion of the wafer specimens in the cleaning solution, stir at the specified treatment temperature shown in the table and 300 rpm. After 60 minutes of immersion, take out the wafer specimens from the cleaning solution, wash them with water at room temperature for 30 seconds, and dry them by nitrogen purging.

[0195] Measure the film thickness of the wafer specimens before and after immersion in the cleaning solution.

[0196] The film thicknesses of the wafer specimens with TiN film, W film, and Mo film respectively were measured using a fluorescent X-ray device (ZSX PrimusIV, manufactured by Rigaku Corporation).

[0197] Then, the etching rate was calculated based on the changes in the film thicknesses of the TiN film, W film, and Mo film before and after the cleaning treatment.

[0198] · Evaluation of the removability of etching residues

[0199] Regarding the removability of etching residues, using the etching rate of the TiN film by the cleaning solution as an index, the evaluation was carried out according to the following evaluation criteria. The results are shown in Tables 1 - 2.

[0200] The higher the value of this etching rate, the more excellent the removability of etching residues means.

[0201] · Evaluation criteria for the removability of etching residues

[0202] Etching rate of the cleaning solution on the TiN film

[0203] A: Exceeding 0.4×10 -10 m / min.

[0204] B: 0.1×10 -10 m / min or more and 0.4×10 -10 m / min or less.

[0205] C: Less than 0.1×10 -10 m / min.

[0206] · Evaluation of the reduction of metal damage

[0207] Regarding the reduction of metal damage, the etching rate of the cleaning solution on the W film (W E.R.) and the etching rate of the cleaning solution on the Mo film (Mo E.R.) were used as indices for evaluation. The values of each etching rate are shown in Tables 1 - 2.

[0208] The lower the value of each etching rate, the more the damage to the metal (such as metal wiring) is reduced means.

[0209] [Table 1]

[0210]

[0211] [Table 2]

[0212]

[0213] Based on the results shown in Tables 1 to 2, it was confirmed that when using the cleaning liquids of Examples 1 to 13 and Examples 14 to 25 to which the present invention is applied, both the removability of etching residues and the reduction of metal damage are good.

[0214] On the other hand, when using the cleaning liquids of Comparative Examples 1, 2, 4, 5, 6, and 8 outside the scope of the present invention, either the removability of etching residues or the reduction of metal damage is poor.

[0215] In addition, in the cleaning liquids of Comparative Examples 3 and 7, hydroxylamine is used as a residue remover. The residue remover of the cleaning liquids of Examples 1 to 13 and Examples 14 to 25 is replaced by compound (A), improving safety.

[0216] As described above, although the preferred embodiments of the present invention have been described, the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other changes to the composition can be made without departing from the gist of the present invention. The present invention is not limited by the above description, but is only limited by the scope of the appended claims.

[0217] Description of Reference Numerals

[0218] 10 Substrate

[0219] 20 Metal Wiring Layer

[0220] 30 Etching Stop Layer

[0221] 40 Interlayer Insulating Film

[0222] 50 Hard Mask Layer (HM Layer)

[0223] 60 Dry Etching Residue

[0224] 100 Component.

Claims

1. A cleaning liquid for removing etching residues containing inorganic substances, characterized in that, Comprising: Compound (A), represented by the following general formula (a1); At least one base selected from the group consisting of amines and ammonium compounds other than the said Compound (A), [Chemical formula 1] In the formula, -R is -NH2 or -O-C(CH3)3.

2. The cleaning liquid according to claim 1, characterized in that, The pH measured at 23°C is 8.0 or higher.

3. The cleaning liquid according to claim 1, wherein, The said base is at least one selected from the group consisting of ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide, alkanolamine and triamine.

4. The cleaning liquid according to claim 1, characterized in that, The content of the said base is 15 to 5000 parts by mass relative to 100 parts by mass of the said Compound (A).

5. The cleaning liquid according to claim 1, characterized in that, The said cleaning liquid is used for cleaning a substrate after dry etching by a wiring process.

6. A cleaning method for a substrate, characterized in that, Including: Step (P1), cleaning a substrate with an etching residue containing inorganic substances using the cleaning liquid according to any one of claims 1 to 5.

7. The cleaning method of the substrate according to claim 6, characterized in that, In the said Step (P1), the operation of cleaning the substrate with the cleaning liquid is carried out under the condition of 10 to 80°C.

8. The cleaning method of the substrate according to claim 6, characterized in that, The said substrate is a substrate after dry etching by a wiring process.

9. A method for manufacturing a semiconductor device, characterized in that, Including: Step (P1), cleaning a substrate with an etching residue containing inorganic substances using the cleaning liquid according to any one of claims 1 to 5.

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