Cleaning compositions and cleaning methods using the same
By using a cleaning composition consisting of a mixture of water, fluorine compounds, alkanolamine compounds, and specific corrosion inhibitors, the problem of removing residues after etching semiconductor substrates, which is difficult to remove in the prior art, is solved, achieving protection and efficient cleaning of the metal layer.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ENF TECH CO LTD
- Filing Date
- 2021-09-15
- Publication Date
- 2026-05-22
AI Technical Summary
Existing cleaning compositions are ineffective at removing etched or ashed residues from semiconductor substrates and may cause corrosion or damage to the metal layers.
A mixture containing water, fluorine compounds, alkanolamine compounds, and corrosion inhibitors is used. The corrosion inhibitors consist of a first corrosion inhibitor and a second corrosion inhibitor with a specific structure, and the pH value is between 7 and 14. This mixture is used to clean semiconductor substrates and prevent corrosion of the metal layers.
It significantly improves the ability to clean up residues after etching, inhibits corrosion of the metal layer, ensures the integrity of the semiconductor substrate, and removes photoresist polymer residues in a short time.
Smart Images
Figure CN114437882B_ABST
Abstract
Description
[0001] Cross-reference of related applications
[0002] This application claims priority to Korean Patent Application No. 10-2020-0143375, filed on October 30, 2020, with the Korean Intellectual Property Office under 35U.SC§119, the disclosure of which is incorporated herein by reference in its entirety. Technical Field
[0003] The following disclosure relates to cleaning compositions for removing etched or ashing residues from semiconductor substrates, and cleaning methods using the same. Background Technology
[0004] In the manufacture of semiconductor devices, photolithography using photoresist has been widely used to form vias or contact holes for interconnecting conductive metal wiring patterns or patterned wiring. To form metal wiring, vias, or contact holes on a semiconductor substrate using photolithography, the following processes are performed: 1) forming a predetermined photoresist pattern on the layer to be etched; 2) using the photoresist pattern as a contact mask, obtaining the pattern or via through an etching process such as plasma etching, reactive ion etching (RIE), or ion grinding; and 3) removing the photoresist used as the mask by oxygen plasma etching.
[0005] Meanwhile, the etching gases widely used in plasma etching and reactive ion etching interact with the layers to be etched, such as those made of aluminum, tungsten, and titanium, or with photoresists used as contact masks during the etching process, producing byproducts such as organometallic materials and sidewall polymers. Even after oxygen plasma ashing, these byproducts, known as sidewall polymers, shielding materials, and barriers, remain on the substrate. Even with organic solvents such as pyrrolidone, dimethyl sulfone, dichloromethane, dimethylformamide, or dimethylacetamide, these byproducts are not completely removed. These byproducts contaminate the substrate or the surface of the semiconductor device, hindering subsequent processes. In other words, these byproducts not only reduce process efficiency but also pose fatal problems to the reliability and functionality of highly integrated and miniaturized semiconductor devices. Therefore, research on cleaning agents and methods capable of substantially completely removing these byproducts is actively underway.
[0006] As examples, Patent Documents 1 and 2 disclose cleaning compositions composed of mixtures of dimethylformamide, alkanolamines, etc. Furthermore, Patent Documents 3 and 4 disclose cleaning compositions composed of mixtures of 2-pyrrolidone, dialkyl sulfone, alkanolamines, etc. Further, Patent Document 5 discloses a cleaning composition composed of 2-pyrrolidone and tetramethylammonium hydroxide. However, there is a problem with the short lifespan of these cleaning compositions because high temperatures are required to remove sidewall polymers using these compositions.
[0007] As another example, Patent Document 6 discloses a cleaning composition comprising ammonia, hydrofluoric acid, acetic acid, and water, and having a pH of 7 to 12. However, when the cleaning composition disclosed in Patent Document 6 is used on alloys containing aluminum or reactive metals such as aluminum or titanium, or amphoteric metals such as copper or tungsten, corrosion problems arise due to the reaction between the alkaline cleaning composition and the metal.
[0008] Therefore, in substrates or semiconductor devices including metal layers containing various metals such as aluminum, titanium, tungsten, copper or cobalt, or insulating films containing silicon oxide, there is an urgent need in the art to develop cleaning compositions and cleaning methods that can effectively remove residues present on the surface of the substrate or semiconductor device without damaging the surface.
[0009] [Related Literature]
[0010] [Patent Literature]
[0011] (Patent Document 1) US 4,770,713 A
[0012] (Patent Document 2) US 4,403,029 A
[0013] (Patent Document 3) US 4,428,871 A
[0014] (Patent Document 4) US 4,401,747 A
[0015] (Patent Document 5) US 4,744,834 A
[0016] (Patent Document 6) KR 10-2003-0035207 A Summary of the Invention
[0017] Embodiments of the present invention relate to providing cleaning compositions capable of effectively removing etched or ashing residues from semiconductor substrates, and cleaning methods using the same.
[0018] Another embodiment of the invention relates to providing a cleaning composition that does not cause damage to the surface of the object to be cleaned and does not leave residue on the surface of the object to be cleaned, and a cleaning method using the same.
[0019] Another embodiment of the present invention relates to a method for manufacturing a semiconductor device, the method being used to provide a semiconductor device with excellent performance and high process yield by effectively removing residues present on the surface of an object to be cleaned.
[0020] In one general aspect, a cleaning composition is provided, the cleaning composition comprising: water; a fluorinated compound; an alkanolamine compound; and a corrosion inhibitor, wherein the corrosion inhibitor is a mixture of a first corrosion inhibitor represented by Formula 1 and a second corrosion inhibitor represented by Formula 2.
[0021] [Formula 1]
[0022]
[0023] [Equation 2]
[0024]
[0025] in,
[0026] R1 and R3 are each independently a halogen, amino, hydroxyl, cyano, nitro, carboxyl group, or C group. 1-20 Alkoxy, C 1-20 Alkyl or C 1-20 aminoalkyl;
[0027] R2 and R4 are each independently hydrogen or C. 1-20 Alkyl groups; and
[0028] n and m are each an integer selected independently from 0 to 4.
[0029] In formulas 1 and 2, R1 and R3 can each independently be a halogen, amino, hydroxyl, cyano, nitro, carboxyl group, or C. 1-7 Alkoxy, C 1-7 Alkyl or C 2-7 Aminoalkyl; R2 and R4 can each be hydrogen or C independently. 1-7 Alkyl group; and n and m can each be an integer of 0 or 1 independently.
[0030] In equations 1 and 2, R1 and R3 can each be C independently. 1-7 Alkyl group; R2 and R4 can each be hydrogen or C independently. 1-7 Alkyl group; and n and m can be integers of 1.
[0031] The corrosion inhibitor may be a mixture based on 1 part by weight of the first corrosion inhibitor and 0.1 to 10 parts by weight of the second corrosion inhibitor.
[0032] The cleaning composition may have a pH of 7 to 14.
[0033] The cleaning composition can be used to remove post-etching or post-ashing residues from substrates used in the semiconductor industry.
[0034] The residue after etching or ashing can be selected from polymer compounds, aluminum-containing compounds, copper-containing compounds, tungsten-containing compounds, cobalt-containing compounds, titanium-containing compounds, and combinations thereof.
[0035] The fluorine compound may include ammonium fluoride.
[0036] In another general aspect, a method for cleaning a semiconductor substrate using the cleaning composition described above is provided.
[0037] The method for cleaning the semiconductor substrate may include a cleaning step of bringing the cleaning composition described above into contact with the surface of the substrate on which etched or ashed residues are present.
[0038] The method for cleaning the semiconductor substrate may include a cleaning step of bringing the cleaning composition described above into contact with the surface of the substrate on which photoresist polymer residues are present.
[0039] The cleaning steps can be performed in the range of 25 to 70°C.
[0040] The semiconductor substrate may include a metal layer comprising a metal selected from aluminum (Al), copper (Cu), tungsten (W), cobalt (Co), and titanium (Ti).
[0041] In another general aspect, a method for manufacturing a semiconductor device is provided, the method comprising a cleaning method for a semiconductor substrate as described above.
[0042] Other features and aspects will be apparent from the following detailed description and claims. Detailed Implementation
[0043] The cleaning compositions and cleaning methods using the present invention for removing etched or ashed residues from semiconductor substrates will be described in detail below. However, unless otherwise defined, the technical and scientific terms used herein have the general meanings understood by one of ordinary skill in the art to which this invention pertains, and descriptions of known functions and configurations that would obscure the invention will be omitted in the following description.
[0044] Furthermore, unless otherwise stated in the context, the singular forms used herein are intended to include the plural forms as well.
[0045] Additionally, unless otherwise specified, all units used herein are based on weight. For example, unless otherwise defined, % or ratio means by weight % or by weight ratio, and by weight % means by weight % of any one component in the total composition.
[0046] In addition, the numerical range used in this paper includes the lower limit, the upper limit, and all values within these ranges, increments logically derived from the type and width of the defined range, all double-defined values, and all possible combinations of the upper and lower limits of the numerical range defined in different forms. Unless otherwise defined in this paper, values outside the defined numerical range that may appear due to experimental error or rounding are also included in the defined numerical range.
[0047] As used herein, the term “comprise” is an “open description” having the same meaning as expressions such as “include,” “contain,” “have,” or “characterize,” and does not exclude elements, materials, or processes not further listed.
[0048] Additionally, as used herein, the term “substantially” means that other elements, materials, or processes not listed together with the specified elements, materials, or processes may be present in an amount or extent that does not have an unacceptably significant effect on at least one fundamental and novel technical idea of the invention.
[0049] As used herein, the term "residue" can be a byproduct generated after etching or ashing of a substrate used in the semiconductor industry, and can refer to contaminant particles or layers of organic or inorganic materials that may be present on the substrate after the process.
[0050] As used herein, the term “dent” refers to an aspect of surface defects generated in metal wiring, and specifically to a form of corrosion in which the metal wiring is corroded and formed in a disc-like manner.
[0051] As used herein, the terms “alkyl,” “alkoxy,” or substituents that include alkyl groups include both straight-chain and branched types.
[0052] As used in this article, the term "halogen" refers to a fluorine, chlorine, bromine, or iodine atom.
[0053] As used herein, the term "aminoalkyl" refers to an alkyl group (*-NR'R) that includes an amino group. Here, R' and R" are each independently hydrogen or C. 1-20 alkyl.
[0054] As used in this article, the term "carboxyl group" refers to *-COOH.
[0055] Conventional cleaning compositions have the disadvantage of causing unnecessary etching or corrosion of the metal or insulating layers. To address these issues, compositions with various additives have been proposed; however, these additives interact with residues, adversely affecting the solubility of the residues in the cleaning composition, or even making the composition difficult to remove from the surface after cleaning.
[0056] Therefore, the inventors have demonstrated that when a combination of cyclic amine-based corrosion inhibitors is used, the ability to clean residues remaining on the surface of substrates used in the semiconductor industry after etching or ashing can be significantly improved, through repeated research to solve the problems mentioned above. Furthermore, the inventors have also demonstrated that when a combination of cyclic amine-based corrosion inhibitors is used, corrosion or damage to metal or insulating layers included in general semiconductor substrates can be prevented, and this invention has been proposed.
[0057] The present invention will be described in detail below.
[0058] The cleaning composition according to the invention comprises a mixture of a first corrosion inhibitor represented by Formula 1 and a second corrosion inhibitor represented by Formula 2.
[0059] Specifically, the cleaning composition according to an exemplary embodiment of the present invention may comprise water; a fluorinated compound; an alkanolamine compound; and a corrosion inhibitor of the combination mentioned above:
[0060] [Formula 1]
[0061]
[0062] [Equation 2]
[0063]
[0064] in,
[0065] R1 and R3 are each independently a halogen, amino, hydroxyl, cyano, nitro, carboxyl group, or C group. 1-20 Alkoxy, C 1-20 Alkyl or C 1-20 aminoalkyl;
[0066] R2 and R4 are each independently hydrogen or C. 1-20 Alkyl groups; and
[0067] n and m are each an integer selected independently from 0 to 4.
[0068] In the cleaning composition according to an exemplary embodiment of the present invention, in formulas 1 and 2, R1 and R3 can each independently be a halogen, amino, hydroxyl, cyano, nitro, carboxyl group, C 1-7 Alkoxy, C 1-7 Alkyl or C 2-7 Aminoalkyl; R2 and R4 can each be hydrogen or C independently. 1-7 Alkyl group; and n and m can each be an integer of 0 or 1 independently.
[0069] For example, in formulas 1 and 2, R1 and R3 can each be independently a halogen, hydroxyl, or carboxyl group; R2 and R4 can each be independently hydrogen or C. 1-7 Alkyl group; and n and m can be integers of 1.
[0070] For example, in equations 1 and 2, R1 and R3 can each be C independently. 1-7 Alkyl or C 2-7 Aminoalkyl; R2 and R4 can each be hydrogen or C independently. 1-7 Alkyl group; and n and m can each be an integer of 0 or 1 independently.
[0071] In the cleaning composition according to an exemplary embodiment of the present invention, in formulas 1 and 2, R1 and R3 can each independently be C 1-7 Alkyl group; R2 and R4 can each be hydrogen or C independently. 1-7 Alkyl group; and n and m can be integers of 1.
[0072] For example, in equations 1 and 2, R1 and R3 can each be C independently. 1-4 Alkyl group; R2 and R4 can each be hydrogen or C independently. 1-4 Alkyl group; and n and m can be integers of 1.
[0073] For example, in equations 1 and 2, R1 and R3 can each be a straight chain C independently. 1-3 Alkyl group; R2 and R4 can each be hydrogen or straight-chain C independently. 1-3 Alkyl group; and n and m can be integers of 1.
[0074] For example, in formulas 1 and 2, both R1 and R3 can be methyl or ethyl.
[0075] The first corrosion inhibitor may include, but is not limited to: benzotriazole, 5-aminobenzotriazole, 1-hydroxybenzotriazole, 5-chlorobenzotriazole, 4-chlorobenzotriazole, 5-bromobenzotriazole, 4-bromobenzotriazole, 5-fluorobenzotriazole, 4-fluorobenzotriazole, tolyltriazole, 5-nitrobenzotriazole, 4-nitrobenzotriazole, 1-aminobenzotriazole, benzotriazole-5-carboxylic acid, 4-methylbenzotriazole, 4-ethylbenzotriazole, 5-ethylbenzotriazole, 4-propylbenzotriazole, 5-propylbenzotriazole, 4-isopropylbenzotriazole, 5-isopropylbenzotriazole, 4-n-butylbenzotriazole, 5-n-butylbenzotriazole, 4-isopropylbenzotriazole, 4-isopropylbenzotriazole, 5-isopropyl ...5-isopropylbenzotriazole, 4-isopropylbenzotriazole, 5-isopropylbenzotri Butylbenzotriazole, 5-isobutylbenzotriazole, 4-pentylbenzotriazole, 5-pentylbenzotriazole, 4-hexylbenzotriazole, 5-hexylbenzotriazole, 5-methoxybenzotriazole, 5-hydroxybenzotriazole, dihydroxypropylbenzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]-benzotriazole, 5-tert-butylbenzotriazole, 5-(1',1'-dimethylpropyl)-benzotriazole, 5-(1',1',3'-trimethylbutyl)benzotriazole, 5-n-octylbenzotriazole, and 5-(1',1',3',3'-tetramethylbutyl)benzotriazole, and may be selected from one, two, or more of them.
[0076] The second corrosion inhibitor may include, but is not limited to, 4,5,6,7-tetrahydro-1H-benzotriazole, 5-methyl-4,5,6,7-tetrahydro-1H-benzotriazole, 6-methyl-4,5,6,7-tetrahydro-1H-benzotriazole, 5,6-dimethyl-4,5,6,7-tetrahydro-1H-benzotriazole and 4,6-dimethyl-4,5,6,7-tetrahydro-1H-benzotriazole, and may be selected from one, two or more of them.
[0077] Cleaning compositions containing alkanolamine and hydroxylamine compounds are known to exhibit high etching rates on metals used as metal wiring materials (e.g., aluminum), resulting in a high probability of pitting in the metal wiring. However, by using the corrosion inhibitors of the aforementioned combination to adjust the etching rate of the metal layer including aluminum, pitting can be significantly suppressed. In particular, the cleaning compositions according to the invention exhibit excellent cleaning of residues without causing any damage to metal layers containing metals selected from copper (Cu), tungsten (W), cobalt (Co), and titanium (Ti), such as corrosion, undercuts, whiskers, pitting, notch wear, etc. Furthermore, the cleaning compositions according to the invention can remove photoresist polymer residues in a short time.
[0078] Furthermore, compared to cases where only the first or second corrosion inhibitor is included, the cleaning composition according to the present invention exhibits maximized corrosion inhibition.
[0079] Therefore, the cleaning composition according to the invention can be a cleaning composition for removing residual metal particles generated after etching or ashing from substrates used in the semiconductor industry. Additionally, the cleaning composition according to the invention can be a cleaning composition for removing organometallic materials generated after etching or ashing. Furthermore, the cleaning composition according to the invention can be a cleaning composition for removing photoresist polymer residues, which are sidewall polymers generated after etching or ashing.
[0080] In the cleaning composition according to an exemplary embodiment of the present invention, the residues after etching or ashing may be selected from polymer compounds, copper-containing compounds, tungsten-containing compounds, cobalt-containing compounds, titanium-containing compounds, and combinations thereof.
[0081] In a cleaning composition according to an exemplary embodiment of the invention, the corrosion inhibitor may be a mixture based on 1 part by weight of a first corrosion inhibitor, mixed with 0.1 to 10 parts by weight, particularly 0.5 to 8 parts by weight, and more particularly 1.0 to 5 parts by weight of a second corrosion inhibitor.
[0082] The cleaning composition according to an exemplary embodiment of the present invention can have a pH of 7 to 14. That is, the cleaning composition can effectively remove residual metal particles, metal ions, organic materials, etc. in the alkaline pH range, and after cleaning, the metal ions in the composition can be stably collected to prevent metal ions from re-contaminating the substrate surface.
[0083] For example, the cleaning composition may have a pH of 8 to 12.
[0084] For example, the cleaning composition may have a pH of 9 to 11.
[0085] The water included in the cleaning composition according to an exemplary embodiment of the invention is not particularly limited, but in particular it can be deionized water. More specifically, the deionized water is deionized water used in semiconductor processes and can have a resistivity of 18 MΩ·cm or greater.
[0086] In the cleaning composition according to an exemplary embodiment of the present invention, the alkanolamine may be an alkanolamine having 2 to 10 carbon atoms. Alkanolamines may include, but are not limited to: monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, N-methyldiethanolamine, N,N-dimethylethanolamine, N-ethyldiethanolamine, N,N-diethylethanolamine, 2-(2-aminoethylamino)-1-ethanol, 1-amino-2-propanol, 2-amino-1-propanol, 3-amino-1-propanol, 4-amino-1-butanol, dibutanolamine, (methoxymethyl)diethanolamine, (hydroxyethoxymethyl)diethylamine, methyl(methoxymethyl)aminoethanol, methyl(butoxymethyl)aminoethanol, 2-(2-aminoethoxy)ethanol, 1-(2-hydroxyethyl)piperazine, 1-(2-hydroxyethyl)methylpiperazine, N-(2-hydroxyethyl)morpholine, and N-(3-hydroxypropyl)morpholine, and may preferably include straight-chain alkanolamines.
[0087] In the cleaning composition according to an exemplary embodiment of the present invention, the fluorine compound may comprise ammonium fluoride (NH4F).
[0088] For example, the cleaning composition may further comprise hydrogen fluoride (HF), ammonium hydrogen fluoride (NH4HF2), or a combination thereof.
[0089] A cleaning composition according to an exemplary embodiment of the present invention may include, based on the total weight of the cleaning composition, 0.001 to 5% by weight of a fluorinated compound, 0.1 to 10% by weight of an alkanolamine compound, 0.001 to 5% by weight of a corrosion inhibitor, and the remainder being water. Specifically, the cleaning composition may include 0.005 to 3% by weight of a fluorinated compound, 0.5 to 8% by weight of an alkanolamine compound, 0.005 to 3% by weight of a corrosion inhibitor, and the remainder being water; and more specifically, 0.01 to 2% by weight of a fluorinated compound, 1 to 7% by weight of an alkanolamine compound, 0.01 to 2% by weight of a corrosion inhibitor, and the remainder being water.
[0090] If the composition described above is satisfied, it is preferred that the residues dissolved and cleaned in the chemical solution do not cause the residues to redeposit and re-adsorb onto the substrate surface as residues, and that the metal or insulating layers contained in the semiconductor substrate are not unnecessarily over-etched or corroded.
[0091] In addition, in the cleaning composition, the corrosion inhibitor is a mixture of a first corrosion inhibitor (A) and a second corrosion inhibitor (B), which can be mixed in a weight ratio (A:B) that satisfies the following range: 1:0.5 to 1:10 or 1:0.5 to 1:8 or 1:1 to 1:5.
[0092] In addition, the cleaning compositions according to embodiments of the present invention may be substantially free of additional additives selected from oxidants, organic acids and quaternary organic ammonium salts.
[0093] For example, oxidants may include hydrogen peroxide, nitric acid, perchloric acid, hypochlorous acid, ammonium peroxide, boron, or iodine. Cleaning compositions containing the oxidants mentioned above may not completely remove contaminants, such as photoresist polymer residues, and may cause damage to the metal layer.
[0094] Examples of quaternary organic ammonium salts may include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), benzyltrimethylammonium hydroxide (BTMAH), benzyltriethylammonium hydroxide (BTEAH), (2-hydroxyethyl)trimethylammonium hydroxide, (2-hydroxyethyl)triethylammonium hydroxide, (2-hydroxyethyl)tripropylammonium hydroxide, (1-hydroxypropyl)trimethylammonium hydroxide, ethyltrimethylammonium hydroxide, diethyldimethylammonium hydroxide (DEDMAH), or tris(2-hydroxyethyl)methylammonium hydroxide (THEMAH). When the cleaning composition contains the quaternary organic ammonium salts mentioned above, it may cause damage to the metal layer, and in particular, over-etching or corrosion of metal layers containing copper, cobalt, etc., which is undesirable.
[0095] Examples of organic acids may include acetic acid, formic acid, butyric acid, citric acid, glycolic acid, oxalic acid, malonic acid, valeric acid, propionic acid, tartaric acid, gluconic acid, glycolic acid, or succinic acid. When the cleaning composition contains the quaternary organic ammonium salts mentioned above, it may cause damage to the metal layer by degrading the corrosion inhibitor performance through lowering the pH, and in particular, it may cause corrosion of the metal layer by coordinating with transition metals such as copper and cobalt, which is not preferred.
[0096] In addition, the present invention provides a method for cleaning a semiconductor substrate using the cleaning composition described above, and a method for manufacturing a semiconductor device comprising the thereof.
[0097] Aspects of the method for cleaning a semiconductor substrate may include a cleaning step of bringing a cleaning composition as described above into contact with a surface of the substrate on which etched or ashed residues are present.
[0098] Aspects of the method for cleaning a semiconductor substrate may include a cleaning step of contacting a cleaning composition as described above with a substrate containing photoresist polymer residues.
[0099] Methods for manufacturing semiconductor devices may include the cleaning steps mentioned above.
[0100] Semiconductor substrates can be used without limitation, as long as they are conventional substrates, and in particular, they can be flexible substrates. Non-limiting examples of semiconductor substrates can be selected from flexible glass substrates, silicon wafers, plastic substrates, etc. In this case, the plastic substrate can be, but is not limited to, one or more materials selected from polyimide, polycarbonate, polyphenylene sulfide, and polyarline ether sulfone.
[0101] For example, a semiconductor substrate may include one or more underlying layers selected from metal layers and insulating layers.
[0102] For example, the metal layer may include a metal selected from copper (Cu), tungsten (W), cobalt (Co), and titanium (Ti). Additionally, the metal layer may further include, but is not limited to, one or more metals selected from Ag, Mg, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, Mo, Sn, Zn, and In.
[0103] For example, the insulating layer may include one or more materials selected from amorphous silicon, polycrystalline silicon, silicon oxide, silicon nitride, etc.
[0104] According to the semiconductor substrate cleaning method of an exemplary embodiment of the present invention, the semiconductor substrate mentioned above, i.e., the object to be cleaned, is substantially free from corrosion or damage. That is, only residues present on the object to be cleaned are selectively cleaned, without causing corrosion or damage to the object to be cleaned.
[0105] Specifically, according to the semiconductor substrate cleaning method of an exemplary embodiment of the present invention, a cleaning composition can be applied to the semiconductor substrate to form a photoresist pattern on the semiconductor substrate. In this case, the semiconductor substrate may be the result of etching the layer to be etched using the photoresist pattern as an etch mask, and the object to be cleaned using the cleaning composition may be the semiconductor substrate. That is, the cleaning composition can clean photoresist polymer residues. Furthermore, the cleaning ability of the object to be cleaned can be evaluated based on the following criteria.
[0106] For example, the removal time for photoresist polymer residues can be 90 seconds or less, or 60 seconds or less.
[0107] There are no restrictions on the polymers included in the photoresist, as long as they are conventional.
[0108] Specifically, according to the semiconductor substrate cleaning method of an exemplary embodiment of the present invention, a cleaning composition may be applied to a semiconductor substrate including a metal layer. During cleaning, the etch rate of the metal layer may be... Or even smaller. Additionally, the absence of corrosion or damage to the object being cleaned can be evaluated based on the following criteria.
[0109] For example, when the metal layer is a copper layer, the etching rate of the copper layer can be... Or smaller.
[0110] For example, when the metal layer is a cobalt layer, the etching rate of the cobalt layer can be... Or smaller.
[0111] For example, when the metal layer is a tungsten layer, the etching rate of the tungsten layer can be less than [a certain value].
[0112] For example, it can meet all the criteria mentioned above.
[0113] In addition, etching can be a drying process, and after etching, it can further include a process of removing the photoresist pattern primarily by ashing.
[0114] Alternatively, cleaning can be performed using a single type or in batches of equipment.
[0115] In the semiconductor substrate cleaning method according to an exemplary embodiment of the present invention, the temperature for performing the cleaning step can vary depending on the type and state of the photoresist to be removed, but is preferably in the range of 25 to 70°C. The cleaning step can be performed particularly in the range of 25 to 60°C, and more particularly in the range of 30 to 50°C. That is, according to the present invention, excellent cleaning ability can be achieved even under mild temperature conditions. Furthermore, the cleaning step can be performed at the temperature conditions mentioned above by immersing the semiconductor substrate for about 10 to 60 seconds.
[0116] As mentioned above, according to the present invention, it can be applied to the process of cleaning semiconductor devices or their substrates during various aspects of the manufacture of semiconductor devices, such as high-integration and ultra-high-integration processes. Therefore, residues generated after etching or ashing, or photoresist polymer residues on the modified and hardened sidewalls and bottom, can be easily removed in a short time. In particular, the inhibition of corrosion on metal layers containing metals selected from copper (Cu), tungsten (W), cobalt (Co), and titanium (Ti) can be maximized, and photoresist polymer residues can be effectively removed. Therefore, the cleaning composition according to the present invention can minimize corrosion of metal layers applied to large-scale semiconductor production lines while completely removing photoresist polymer residues, and thus improve process yield and efficiency. Furthermore, this can provide highly reliable semiconductor devices.
[0117] The invention will be described in more detail below based on embodiments and comparative examples. However, the following embodiments and comparative examples are merely examples for describing the invention in more detail, and the invention is not limited to the following embodiments and comparative examples. Unless otherwise stated in the invention, all temperatures are expressed in °C, and the amounts of compositions used are expressed in % by weight.
[0118] (Evaluation Method)
[0119] 1. Corrosion assessment
[0120] The cleaning compositions prepared in the following examples and comparative examples were subjected to corrosion tests. Specifically, the semiconductor substrate to be corroded was prepared as each silicon wafer, and on each silicon wafer, a... copper layer Cobalt layer and Silicon oxide insulating layer (TEOS film) or Tungsten layer. Before etching began, the thickness of each layer was measured using an ellipsomerometer (JAWOOLLAM, M-2000) and X-ray fluorescence spectroscopy (XRF, EA-1000Ⅲ) (which are thin film thickness measurement devices).
[0121] Subsequently, the etching temperature in the bath was maintained at 30°C, and each semiconductor substrate was immersed in the cleaning composition prepared in the following examples or comparative examples for 10 minutes, followed by etching. After etching, the semiconductor substrates were cleaned with ultrapure water, and then the remaining cleaning agent composition and ultrapure water were completely dried using a drying instrument. Furthermore, the method was evaluated by performing 10 batches without changing the chemical solution used in one batch.
[0122] In this case, the etching rate was calculated by dividing the thickness difference before and after etching by the etching time (minutes) using an ellipsomerometer (JAWOOLLAM, M-2000U) and X-ray fluorescence spectroscopy (XRF, EA-1000III), and the results are shown in Table 2 below.
[0123] 2. Evaluation of the cleaning ability of photoresist polymer residues
[0124] The removal time of photoresist polymer residues was evaluated by testing the cleaning compositions prepared in the following examples and comparative examples. Specifically, the semiconductor substrate to be tested for cleaning capability was prepared using the following method.
[0125] A commonly used positive resist composition [manufactured by Dongjin Semichem Co., Ltd., product name: DPR-i1000] was spin-coated onto the surface of a semiconductor substrate to achieve a final thickness of 1.01 μm. The resist film was then pre-baked on a hot plate at 110°C for 90 seconds. Subsequently, a mask with a predetermined pattern was placed on the resist film, irradiated with UV light, and developed with 2.38% by weight tetramethylammonium hydroxide (TMAH) developer at 21°C for 60 seconds to form a photoresist pattern. The sample with the photoresist pattern formed thereon was then hard-baked on a hot plate at 120°C for 100 seconds. Using the resist pattern formed on the sample as a mask, a Cl2 / BCl3 mixed gas was used as the etching gas in a dry etching instrument (Applied Materials, model name: DPS+) to etch the underlying layer of titanium nitride for EPD+ 45 seconds. Then, most of the photoresist was removed using an O2 plasma through an ashing instrument to complete the sample.
[0126] Subsequently, the etching temperature in the bath was maintained at 50°C, and the sample manufactured by the above method was immersed in the cleaning composition prepared in the following examples or comparative examples, and then etched. The time taken to remove the photoresist polymer residue was then measured by evaluating every 30 seconds. The removal of the photoresist polymer residue was observed using a scanning electron microscope (SEM, S-4800, Hitachi), and the results are shown in Table 2 below.
[0127] (Examples 1 to 7 and Comparative Examples 1 to 12)
[0128] After mixing the components as shown in Table 1 below, a cleaning composition was prepared by stirring the composition at 500 rpm for 5 minutes at room temperature (25°C). The water content was set to the remainder, such that the total weight of the composition was 100% by weight.
[0129] [Table 1]
[0130]
[0131]
[0132] [Table 2]
[0133]
[0134] As shown in Table 2, the cleaning compositions according to the invention exhibit significantly low etching rates for metal layers containing copper, cobalt, or tungsten. In particular, the cleaning compositions according to the invention have a lower etching rate for copper and cobalt layers than […]. The etching rate, and for tungsten layers smaller than The etching rate. That is, the cleaning composition according to the invention is evaluated as having no corrosion or damage to all these metal layers.
[0135] Furthermore, it has been confirmed that the cleaning composition according to the present invention can completely remove photoresist polymer residues from the surface to be cleaned within a short time. In addition, even after cleaning is completed, no re-adsorption of photoresist polymer residues onto the surface to be cleaned was observed.
[0136] In addition, the cleaning composition according to the invention exhibits excellent stability in chemical solutions after cleaning.
[0137] On the other hand, the comparative examples show that the etching rate of the metal layer mentioned above is significantly higher than the etching rate of the cleaning composition according to the present invention. Specifically, it was confirmed that for Comparative Example 7, the etching rates were as follows: copper layer: Cobalt layer is and tungsten layer as In particular, it was confirmed that the etching rates of the copper or cobalt layers differed significantly for the comparative example.
[0138] Furthermore, comparative examples confirming that the etching rate of the metal layer is up to 22 times higher than that of Comparative Example 1 (Example 1 vs. Comparative Example 1: Cu etching rate). For the reasons described above, Comparative Examples 1 and 2 are not applicable to semiconductor substrates having metal layers containing copper, cobalt, etc., although they show the same level of performance in removing polymer residues as the examples. Additionally, it can be confirmed that when pyrazole is included as an additive, it causes damage not only to the copper layer but also to the cobalt or tungsten layer, and the removal of photoresist polymer residues takes more than twice as long.
[0139] Furthermore, Comparative Example 3, which satisfies the requirement of weak acidity, is not preferred because it does not provide sufficient cleaning ability for photoresist polymer residues and the etching rate of the cobalt layer increases significantly. Additionally, Comparative Examples 8 and 9, which further include an oxidant, also do not provide sufficient cleaning ability for photoresist polymer residues.
[0140] In addition, comparative examples 10 to 12, which use quaternary organic ammonium salts instead of alkanolamine compounds, are not preferred because all etching rates of metal layers containing copper, cobalt, or tungsten show high values, and the stability of the chemical solution is significantly reduced after cleaning.
[0141] The cleaning compositions according to the invention can effectively remove residues present on these surfaces without damaging the substrate or semiconductor device, including metal layers containing various metals such as aluminum, titanium, tungsten, copper, cobalt, or insulating layers containing silicon oxide. Therefore, the cleaning compositions according to the invention are particularly suitable for cleaning substrates or semiconductor devices having metal layers and insulating layers containing various types of metals.
[0142] In particular, the cleaning composition according to the invention can readily remove photoresist polymer residues on the sidewalls and bottom that have been altered and cured by dry etching, wet etching, or ashing processes during wiring formation, via patterning, and other patterning processes in a short time, and can minimize corrosion, drilling, whiskering, pitching, notch wear, etc., of the underlying metal layer. Furthermore, the cleaning composition according to the invention can prevent cleaning residues from redepositing on the surface of the substrate or semiconductor device.
[0143] Therefore, according to the present invention, the object to be cleaned can be effectively cleaned to improve the process yield of subsequent processes, thereby providing a highly reliable semiconductor device in a very economical manner.
[0144] It will be apparent to those skilled in the art that this invention is not limited to the embodiments and drawings mentioned above, but that various substitutions, modifications and alterations can be made without departing from the scope and spirit of this invention.
Claims
1. A cleaning composition comprising: water; Fluorine compounds; Alkylamine compounds; And corrosion inhibitors, The corrosion inhibitor is a mixture of a first corrosion inhibitor represented by Formula 1 and a second corrosion inhibitor represented by Formula 2. The corrosion inhibitor is a mixture based on 1 part by weight of the first corrosion inhibitor and 0.5 to 8 parts by weight of the second corrosion inhibitor. [Formula 1] [Equation 2] in, R1 and R3 are each independently a halogen, amino, hydroxyl, cyano, nitro, or C group. 1-20 Alkoxy, C 1-20 Alkyl or C 1-20 aminoalkyl; R2 and R4 are each independently hydrogen or C. 1-20 Alkyl groups; and n and m are each an independent integer selected from 0 to 4. The cleaning composition described herein does not contain organic acids. The cleaning composition described herein has a pH of 7 to 14. The fluorine compound mentioned above includes ammonium fluoride, and The cleaning composition comprises, by weight, 0.001 to 5% of a fluorine compound, 0.1 to 10% of an alkanolamine compound, 0.001 to 5% of a corrosion inhibitor, and the remainder water, based on the total weight of the cleaning composition.
2. The cleaning composition according to claim 1, wherein, In formulas 1 and 2, R1 and R3 are each independently a halogen, amino, hydroxyl, cyano, nitro, or C group. 1-7 Alkoxy, C 1-7 Alkyl or C 2-7 Aminoalkyl; R2 and R4 are each independently hydrogen or C. 1-7 Alkyl group; and n and m are each an independent integer of 0 or 1.
3. The cleaning composition according to claim 1, wherein, In equations 1 and 2, R1 and R3 are each independently C 1-7 Alkyl group; R2 and R4 are each independently hydrogen or C. 1-7 Alkyl groups; and n and m are integers of 1.
4. The use of the cleaning composition according to claim 1 for removing post-etching or post-ashing residues from substrates used in the semiconductor industry.
5. The use according to claim 4, wherein, The residue is selected from polymer compounds, aluminum-containing compounds, copper-containing compounds, tungsten-containing compounds, cobalt-containing compounds, titanium-containing compounds, and combinations thereof.
6. A method for cleaning a semiconductor substrate, the method comprising a cleaning step of bringing the cleaning composition of claim 1 into contact with a surface of the substrate on which etched or ashing residues are present.
7. A method for cleaning a semiconductor substrate, the cleaning method comprising a cleaning step of bringing the cleaning composition of claim 1 into contact with a surface of the substrate on which photoresist polymer residues are present.
8. The cleaning method according to claim 6, wherein, The cleaning steps are performed in the range of 25 to 70°C.
9. The cleaning method according to claim 7, wherein, The cleaning steps are performed in the range of 25 to 70°C.
10. The cleaning method according to claim 6, wherein, The substrate includes a metal layer, which includes metals selected from the group consisting of aluminum, copper, tungsten, cobalt, and titanium.
11. The cleaning method according to claim 7, wherein, The substrate includes a metal layer, which includes metals selected from the group consisting of aluminum, copper, tungsten, cobalt, and titanium.
12. A method of manufacturing a semiconductor device, the method comprising the cleaning method of the semiconductor substrate according to claim 6.
13. A method of manufacturing a semiconductor device, the method comprising the cleaning method of the semiconductor substrate according to claim 7.