Cleaning solution composition
A cleaning liquid with reducing agents and pH adjusters effectively removes residues and inhibits corrosion on molybdenum surfaces, addressing the inefficiencies of existing CMP cleaning solutions.
Patent Information
- Application Number
- JP2024060070
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-04-03
- Publication Date
- 2025-10-16
AI Technical Summary
Existing cleaning solutions for substrates with molybdenum-containing films after chemical mechanical polishing (CMP) are ineffective in removing abrasive particles and organic residues while minimizing corrosion and maintaining surface flatness.
A cleaning liquid composition comprising one or more reducing agents, water with a pH of 7 or less, and optional pH adjusters, surfactants, and anticorrosive agents to enhance cleaning efficiency and inhibit corrosion on molybdenum surfaces.
The composition effectively removes post-CMP residues and inhibits corrosion of molybdenum, maintaining high surface flatness and stability over time.
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Abstract
Description
[Technical Field]
[0001] The present invention relates to a cleaning liquid composition used for cleaning a substrate having a molybdenum (Mo)-containing film. [Background technology]
[0002] In recent years, with the advancement of miniaturization of devices and the development of multilayer wiring structures, there has been a demand for more precise planarization of substrate surfaces at each stage of semiconductor substrate manufacturing. To address this demand, a new technology called chemical mechanical polishing (CMP) has been introduced. This involves pressing a wafer against an abrasive cloth called a buff while supplying a slurry mixture of abrasive particles and chemicals, and then rotating the buff to combine chemical and physical actions to polish and planarize insulating films and metal materials.
[0003] Chemical mechanical polishing (CMP) is performed using a slurry containing abrasives made of silicon compounds such as alumina and silicon oxide, or cerium compounds such as cerium oxide. After chemical mechanical polishing (CMP), the substrate surface becomes contaminated by particles, typically alumina, silica, or cerium oxide particles, contained in the slurry, as well as metal impurities derived from the constituent materials of the surface being polished and the chemicals contained in the slurry. These post-CMP residues can cause pattern defects, poor adhesion, and poor electrical properties, so they must be completely removed before the next process.
[0004] Traditionally, tungsten (W) has been used for contact plugs that raise electrodes such as the gate, source, and drain of transistors above the insulating film, but as wiring becomes finer, issues such as increased wiring resistance and wiring defects due to electromigration (EM) have emerged. For advanced devices, molybdenum (Mo), which has a high melting point and therefore high EM resistance, and low resistance, is being considered as a material to replace tungsten (W).
[0005] When the chemical mechanical polishing (CMP) process is performed after embedding molybdenum (Mo) wiring, post-CMP residues such as abrasive particles from the slurry and organic residues containing molybdenum (Mo) remain on the wafer surface. Because these post-CMP residues, such as remaining abrasive particles, can cause wiring defects, they are removed in the post-CMP (p-CMP) cleaning process. Furthermore, the surface after cleaning must be highly clean, and deformation due to corrosion of the molybdenum (Mo) wiring must be minimized.
[0006] Patent Document 1 discloses a cleaning liquid composition used for treating a molybdenum-containing substrate, which contains an organic acid and two or more organic amine compounds. [Prior art documents] [Patent documents]
[0007] [Patent Document 1] International Publication No. WO2023 / 189432A1 Summary of the Invention [Problem to be solved by the invention]
[0008] The present inventors have conducted research to develop a cleaning solution composition for substrates having the above-mentioned molybdenum (Mo)-containing film, which efficiently ensures good cleaning properties against post-CMP residues such as abrasive particles derived from the slurry and organic residues containing molybdenum (Mo), while minimizing deformation due to corrosion of the molybdenum (Mo) wiring. That is, the present invention aims to provide a cleaning solution composition that efficiently exhibits good cleaning properties against post-CMP residues such as abrasive particles derived from the slurry and organic residues containing molybdenum (Mo), on substrates having a molybdenum (Mo)-containing film, and minimizes deformation due to corrosion of the molybdenum (Mo) wiring. [Means for solving the problem]
[0009] In the course of intensive research to solve the above problems, the present inventors have found that a cleaning liquid composition containing one or more reducing agents and water and having a pH of 7 or less exhibits good cleaning properties for post-CMP residues such as abrasive grains derived from the slurry and organic residues containing molybdenum (Mo), and is also capable of inhibiting corrosion of molybdenum (Mo) and maintaining high flatness of the molybdenum (Mo) surface. As a result of further research, the present inventors have completed the present invention.
[0010] That is, the present invention relates to the following: [1] A cleaning solution composition for cleaning a substrate having a molybdenum (Mo)-containing film, the cleaning solution composition comprising one or more reducing agents and water, and having a pH of 7 or less. [2] The cleaning liquid composition according to [1] above, wherein the reducing agent is selected from the group consisting of hydroxylamine derivatives, gallic acid, ascorbic acid, and pyrogallol. [3] The cleaning liquid composition according to [2] above, wherein the hydroxylamine derivative is selected from the group consisting of N,N-diethylhydroxylamine, N-methylhydroxylamine, and N,N-dimethylhydroxylamine.
[0011] [4] The cleaning liquid composition according to any one of the above [1] to [3], further comprising one or more pH adjusters. [5] The cleaning liquid composition according to [4] above, wherein the pH adjuster is a quaternary ammonium compound or an inorganic acid. [6] The cleaning liquid composition according to [5] above, wherein the quaternary ammonium compound is trimethyl-2-hydroxyethylammonium hydroxide. [7] The cleaning liquid composition according to [5] above, wherein the inorganic acid is selected from the group consisting of nitric acid, sulfuric acid, hydrofluoric acid, and hydrochloric acid.
[0012] [8] The cleaning liquid composition according to any one of the above [1] to [7], further comprising one or more surfactants. [9] The cleaning liquid composition according to [8], wherein the surfactant is a polysulfonic acid compound.
[0013]
[10] The cleaning liquid composition according to any one of the above [1] to [9], further comprising one or more anticorrosive agents.
[11] The cleaning liquid composition according to
[10] , wherein the anticorrosive agent is a nitrogen-containing ring compound or a thiol compound.
[12] The cleaning liquid composition according to
[11] , wherein the nitrogen-containing ring compound is selected from the group consisting of 1,2,4-triazole, 3-mercapto-1,2,4-triazole, and bismuthiol.
[13] The cleaning liquid composition according to
[11] above, wherein the thiol compound is cysteine or thiosalicylic acid.
[0014]
[14] A concentrate composition for a cleaning liquid composition according to any one of [1] to
[13] above, which is used to obtain the cleaning liquid composition by diluting it 10 to 1000 times.
[15] A method for cleaning a substrate having a molybdenum (Mo)-containing film, comprising a step of contacting the cleaning liquid composition according to any one of [1] to
[13] with the substrate having a molybdenum (Mo)-containing film.
[0015]
[16] A method for producing a semiconductor substrate, comprising a step of contacting the cleaning liquid composition according to any one of [1] to
[13] above with a substrate having a molybdenum (Mo)-containing film.
[17] The method for producing a semiconductor substrate according to
[16] , further comprising a step of chemically mechanically polishing (CMP) the substrate having a molybdenum (Mo)-containing film before the step of contacting the substrate having a molybdenum (Mo)-containing film.
[18] The method for producing a semiconductor substrate according to
[16] or
[17] , wherein the step of contacting the substrate having a molybdenum (Mo)-containing film is a step of cleaning the substrate having a molybdenum (Mo)-containing film. [Effects of the Invention]
[0016] The cleaning liquid composition of the present invention can effectively remove metal impurities and fine particles, particularly abrasive grains derived from the slurry, and post-CMP residues such as organic residues containing molybdenum (Mo), in cleaning the surface of metal materials such as molybdenum (Mo) on substrates that have been subjected to polishing, etching, chemical mechanical polishing (CMP), etc. in the manufacturing process of electronic devices such as semiconductor elements, and can also inhibit corrosion of metals such as molybdenum (Mo) and maintain high flatness of the metal surface. The cleaning solution compositions of the present invention also exhibit high pH stability over time when the reducing agent is a hydroxylamine derivative. The cleaning liquid composition of the present invention can further contain a surfactant, thereby more effectively removing post-CMP residues. Furthermore, by further containing an anticorrosive agent, the cleaning liquid composition of the present invention can further inhibit corrosion of metal materials such as molybdenum (Mo) on a substrate having a molybdenum (Mo)-containing film. [Brief explanation of the drawings]
[0017] [Figure 1] FIG. 10 is a graph showing the cleaning performance of the cleaning liquid compositions of Comparative Example 3 and Example 5 for removing post-CMP residues on a substrate containing Mo, and the solubility of Mo. [Figure 2] FIG. 1 is a graph showing the relationship between the pH and the solubility of Mo in the cleaning liquid compositions of Example 7 and Comparative Examples 4 and 5. [Figure 3] FIG. 1 is a graph showing the cleaning performance of the cleaning liquid compositions of Examples 5 to 8 for removing post-CMP residues on a substrate containing Mo, and the solubility of Mo. DETAILED DESCRIPTION OF THE INVENTION
[0018] The present invention will be described in detail below based on preferred embodiments of the present invention.
[0019] The present invention relates to a cleaning liquid composition for cleaning a substrate having a molybdenum (Mo)-containing film, which comprises one or more reducing agents and water and has a pH of 7 or less.
[0020] The reducing agent used in the present invention is not particularly limited, but examples thereof include hydroxylamine derivatives, gallic acid, ascorbic acid, and pyrogallol.
[0021] A hydroxylamine derivative is a compound in which one or two hydrogens (H) bonded to nitrogen (N) in hydroxylamine (NHOH) are substituted with alkyl groups, preferably alkyl groups having 1 to 2 carbon atoms. Hydroxylamine derivatives are more stable than unsubstituted hydroxylamine (NHOH). Hydroxylamine derivatives also have the property of increasing reactivity by forming a complex with a metal (ion). In other words, in a cleaning liquid composition intended for molybdenum (Mo), the reactivity is selectively increased at the interface between molybdenum (Mo) and the cleaning liquid composition, demonstrating reducing properties. Therefore, the cleaning liquid composition of the present invention containing the above-mentioned hydroxylamine derivative maintains high stability and exhibits excellent reducing properties at the molybdenum (Mo) / cleaning liquid composition interface during use, thereby achieving a cleaning effect. The hydroxylamine derivatives include N,N-diethylhydroxylamine, N-methylhydroxylamine, and N,N-dimethylhydroxylamine, and preferably N,N-diethylhydroxylamine.
[0022] The reducing agent, in one embodiment, is selected from the group consisting of hydroxylamine derivatives, gallic acid, ascorbic acid, and pyrogallol. The reducing agent is preferably a hydroxylamine derivative from the viewpoint of pH stability. One or more reducing agents can be used. The concentration of the reducing agent in the cleaning liquid composition is not limited to this, but is preferably 0.1 mM to 100 mM, and particularly preferably 1 mM to 10 mM. In one embodiment, the cleaning liquid composition of the present invention does not contain gallic acid.
[0023] The cleaning liquid composition of the present invention contains water, and the amount of water is 50 wt % or more, preferably 90 wt % or more, based on the cleaning liquid composition.
[0024] The hydrogen ion concentration (pH) of the cleaning liquid composition of the present invention is 7 or less.
[0025] In one embodiment, the cleaning liquid composition of the present invention may contain a pH adjuster. The pH adjuster is not particularly limited as long as it can adjust the pH to a predetermined level. Examples of the pH adjuster include quaternary ammonium compounds, inorganic acids, potassium hydroxide, sodium hydroxide, and aqueous ammonium solutions, with quaternary ammonium compounds and inorganic acids being preferred.
[0026] Examples of quaternary ammonium compounds include, but are not limited to, tetramethylammonium hydroxide (TMAH), trimethyl-2-hydroxyethylammonium hydroxide (choline hydroxide), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylphenylammonium hydroxide, benzyltrimethylammonium hydroxide, dimethylbis(2-hydroxyethyl)ammonium hydroxide, and methyltris(2-hydroxyethyl)ammonium hydroxide. Preferred are trimethyl-2-hydroxyethylammonium hydroxide (choline hydroxide), tetraethylammonium hydroxide, dimethylbis(2-hydroxyethyl)ammonium hydroxide, and methyltris(2-hydroxyethyl)ammonium hydroxide. Particularly preferred is trimethyl-2-hydroxyethylammonium hydroxide (choline hydroxide).
[0027] Examples of inorganic acids include, but are not limited to, nitric acid, sulfuric acid, hydrofluoric acid, hydrochloric acid, phosphoric acid, etc., and are preferably selected from the group consisting of nitric acid, sulfuric acid, hydrofluoric acid, and hydrochloric acid, with nitric acid being particularly preferred.
[0028] One or more pH adjusters can be used. From the viewpoint of reducing toxicity to the human body, the cleaning liquid composition of the present invention preferably does not contain tetramethylammonium hydroxide (TMAH), which is a quaternary ammonium compound.
[0029] In one embodiment, the cleaning liquid composition of the present invention may contain a surfactant. The cleaning liquid composition of the present invention, by containing a surfactant, can more effectively remove post-CMP residues, such as abrasive grains derived from the slurry and organic residues containing molybdenum (Mo), from a substrate having a molybdenum (Mo)-containing film. The surfactant is appropriately selected depending on the fine particles and substrate to be removed, and is not particularly limited. Examples of the surfactant include polysulfonic acid compounds, polycarboxylic acid compounds, and polyphosphonic acid compounds, and polysulfonic acid compounds are preferred.
[0030] Examples of the polysulfonic acid compound include naphthalenesulfonic acid formaldehyde condensate, polystyrenesulfonic acid, ligninsulfonic acid, and salts thereof, with naphthalenesulfonic acid formaldehyde condensate being preferred. One or more surfactants can be used. The concentration of the surfactant in the cleaning liquid composition is not limited to this, but is preferably 1 ppm to 10,000 ppm, and particularly preferably 1 ppm to 100 ppm.
[0031] In one embodiment, the cleaning liquid composition of the present invention may contain a corrosion inhibitor. The cleaning liquid composition of the present invention contains an anticorrosive agent, and thus can further inhibit corrosion of metal materials such as molybdenum (Mo) on a substrate having a molybdenum (Mo)-containing film. The anticorrosive agent is not limited to these, but examples thereof include nitrogen-containing ring compounds, thiol compounds, and sulfur-containing ring compounds, and nitrogen-containing ring compounds and thiol compounds are preferred.
[0032] Examples of the nitrogen-containing ring compound include, but are not limited to, pyrrole, pyrazoline, pyrazole, imidazole, triazole, imidazoline, oxazoline, oxazole, isoxazole, and derivatives thereof. Specific examples include 1H-pyrrole, 1-pyrroline, 2-pyrroline, 3-pyrroline, pyrrolidine, pyrrolidone, γ-butyrolactam, γ-valerolactam, proline, prolyl, hygric acid, hygroyl, minalin, 1H-pyrazole, 1-pyrazoline, 2-pyrazoline, pyrazolidine, pyrarizolidone, 3-pyrazolone, 4-pyrazolone, 5-pyrazolone, 1H-pyrazole-4-carboxylic acid, 1-methyl-1H-pyrazole-5-carboxylic acid, 5-methyl-1H-pyrazole-3-carboxylic acid, 3, Examples of such anti-inflammatory agents include 5-pyrazoledicarboxylic acid, 3-amino-5-hydroxypyrazole, 1H-imidazole, 2-imidazoline, 3-imidazoline, 4-imidazoline, imidazolidine, imidazolidone, 1,3,4-thiadiazole, 5-mercapto-1,3,4-thiadiazole, 2-amino-5-mercapto-1,3,4-thiadiazole, bismuthiol, ethyleneurea, hydantoin, allantoin, histidine, histidyl, histamine, 1,2,3-triazole, 1,2,4-triazole, 1-hydroxybenzotriazole, 3-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, 4-ano-1,2,4-triazole, and 3,5-diamino-1,2,4-triazole. As the nitrogen-containing ring compound, from the viewpoints of industrial availability and high water solubility, preferred are pyrazole, 3,5-pyrazoledicarboxylic acid, 3-amino-5-hydroxypyrazole, imidazole, triazole, 3-mercapto-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, histidine, and histamine, and particularly preferred are 1,2,4-triazole, 3-mercapto-1,2,4-triazole, 5-mercapto-1,3,4-thiadiazole, and bismuthiol.
[0033] Examples of thiol compounds include, but are not limited to, methanethiol, 2-aminoethanethiol, 2-mercaptoethanol, 1-thioglycerol, thioglycolic acid, 3-mercaptopropionic acid, allyl mercaptan, propanethiol, cyclopentanethiol, 2-methyl-1-butanethiol, 1,2-ethanedithiol, 1,3-propanedithiol, benzenethiol, 4-aminobenzenethiol, 2-hydroxybenzenethiol, thiosalicylic acid, 1,4-benzenedithiol, 2-mercaptopyridine, 2-mercaptopyrimidine, 2-mercaptopyrazine, 3-furanthiol, 2-mercaptoimidazole, 2-thiophenethiol, cyclohexanethiol, 2-mercaptothiazole, 2-mercaptothiazoline, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, cysteine, homocysteine, and N-acetylcysteine. Particularly preferred are cysteine and thiosalicylic acid. Examples of sulfur-containing ring compounds include, but are not limited to, thiophene, 2-methylthiophene, 3-methylthiophene, 3-fluorothiophene, 2-aminomethylthiophene, 2-thiophenemethanol, 3-thiophenemethanol, 2-thiophenecarboxylic acid, and 3-thiophenecarboxylic acid.
[0034] One or more types of anticorrosive agents can be used. The concentration of the anticorrosive agent in the cleaning liquid composition is not limited to this, but is preferably 0.01 mM to 100 mM, and particularly preferably 0.1 mM to 10 mM.
[0035] In one embodiment, the cleaning liquid composition of the present invention does not contain a combination of gallic acid and cysteine.
[0036] The substrate having a molybdenum (Mo)-containing film in the present invention is not limited to a substrate obtained after chemical mechanical polishing (CMP), but examples thereof include a substrate immediately after CMP, a substrate on which a molybdenum (Mo)-containing film such as a molybdenum (Mo) contact plug and / or a molybdenum (Mo) wiring is formed and then immediately after processing the upper insulating film by dry etching, etc. Among these, a substrate immediately after chemical mechanical polishing (CMP) is preferred.
[0037] The chemical mechanical polishing (CMP) in the present invention can be performed in accordance with known chemical mechanical polishing methods, including, but not limited to, polishing methods using abrasive grains such as silicon oxide (SiO2) or alumina (Al2O3), and abrasive-less polishing methods using electrolytic water. Of these, polishing methods using abrasive grains such as silicon oxide (SiO2) or alumina (Al2O3) are preferred.
[0038] The cleaning liquid composition of the present invention can be obtained by diluting the concentrate composition of the present invention. The cleaning liquid composition of the present invention can be obtained by diluting the concentrate composition, for example, but not limited to, 10 times or more, preferably 10 to 1000 times, more preferably 50 to 200 times, but the dilution amount is appropriately determined depending on the composition.
[0039] Since the cleaning liquid composition of the present invention is mostly composed of water, when a dilution and mixing device is installed in the production line of electronic devices, the cleaning liquid composition can be supplied as an undiluted liquid composition and diluted with a diluting liquid containing water (including a diluting liquid consisting only of ultrapure water) immediately before use. This has the advantage of contributing to reduced transportation costs, reduced carbon dioxide gas emissions during transportation, and reduced production costs for electronic device manufacturers.
[0040] The cleaning liquid composition of the present invention is suitable for use on a substrate having a molybdenum (Mo)-containing film, and is particularly suitable for use on a substrate having a molybdenum (Mo) contact plug and / or a molybdenum (Mo) wiring. In one embodiment, the cleaning liquid composition of the present invention may be used on a substrate not containing copper (Cu). The cleaning solution composition of the present invention is also suitable for use on substrates after chemical mechanical polishing (CMP). The surface of the substrate after CMP may contain various wirings, barrier metal materials (CoTi-based compounds, Ta-based compounds, Ru, etc.), and insulating film materials (SiO2, low-k), as well as fine particles and metal impurities contained in the slurry. The fine particles are primarily alumina, silica, and cerium oxide, for example. Metal impurities include copper (Cu) dissolved in the slurry during polishing and redeposited thereon, iron (Fe) derived from the oxidizing agent in the slurry, and molybdenum (Mo) organometallic complexes formed by the reaction of molybdenum (Mo) with a molybdenum (Mo) corrosion inhibitor contained in the slurry.
[0041] In the present invention, the barrier metal refers to cobalt (Co), titanium (Ti)-based compounds, tantalum (Ta)-based compounds, ruthenium (Ru), etc., which are used in a layer (barrier metal layer) formed between a contact plug or wiring of a semiconductor substrate and an insulating film in order to prevent the metal in the contact plug or wiring from diffusing into the insulating film.
[0042] Low-k materials are materials with low dielectric constants used for interlayer insulating films, etc., and include, but are not limited to, porous silicon, silicon-containing organic polymers, TEOS (tetraethoxysilane), etc. Specific examples include Black Diamond (manufactured by Applied Materials, Inc.) and Aurora (manufactured by ASM International).
[0043] The present invention also relates to a method for cleaning a substrate having a molybdenum (Mo)-containing film, which comprises the step of contacting the substrate having a molybdenum (Mo)-containing film with the cleaning liquid composition of the present invention.
[0044] The present invention still further relates to a method for producing a semiconductor substrate, which comprises a step of contacting a substrate having a molybdenum (Mo)-containing film with the cleaning liquid composition of the present invention. In one embodiment, a method for producing a semiconductor substrate includes a step of chemically mechanically polishing (CMP) a substrate having a molybdenum (Mo)-containing film before a step of contacting the substrate having a molybdenum (Mo)-containing film with the cleaning liquid composition of the present invention.
[0045] Examples of contacting steps include, but are not limited to, a cleaning step after chemical mechanical polishing (CMP) and a cleaning step after processing an insulating film on a molybdenum (Mo) contact plug by dry etching. Examples of contacting methods include, but are not limited to, a single-wafer cleaning method that also uses brush scrubbing, a single-wafer cleaning method in which a cleaning solution is sprayed from a spray or nozzle, a batch spray cleaning method, and a batch immersion cleaning method. Of these, preferred are the single-wafer cleaning method that also uses brush scrubbing and the single-wafer cleaning method in which a cleaning solution is sprayed from a spray or nozzle, and particularly preferred is the single-wafer cleaning method that also uses brush scrubbing.
[0046] The atmosphere in which the contact is carried out is not limited to, but includes, for example, air, a nitrogen atmosphere, and a vacuum, among which air and a nitrogen atmosphere are preferred. The contact time is not particularly limited and is appropriately selected depending on the purpose, but is 0.5 to 5 minutes in the case of a single wafer cleaning method in which brush scrubbing is used in combination and a single wafer cleaning method in which a cleaning solution is sprayed from a spray or nozzle, and is 0.5 to 30 minutes in the case of a batch type spray cleaning method and a batch type immersion cleaning method. The temperature is not particularly limited and is appropriately selected depending on the purpose, but is 20°C to 50°C in the case of a single wafer cleaning method in which brush scrubbing is used in combination and a single wafer cleaning method in which a cleaning solution is sprayed from a spray or nozzle, and is 20°C to 100°C in the case of a batch type spray cleaning method and a batch type immersion cleaning method. The above-mentioned contact conditions can be combined appropriately depending on the purpose.
[0047] Examples of semiconductor substrates include, but are not limited to, silicon, silicon carbide, silicon nitride, gallium arsenide, gallium nitride, gallium phosphide, indium phosphide, etc. Among these, silicon, silicon carbide, gallium arsenide, and gallium nitride are preferred, and silicon and silicon carbide are particularly preferred. [Example]
[0048] Next, the cleaning liquid composition of the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these.
[0049] 1. Preparation of cleaning solution composition First, cleaning liquid compositions according to Examples 1 to 15 and Comparative Examples 1 to 5 were prepared. Specifically, as shown in Table 1, a reducing agent, a surfactant, an anticorrosive agent, and / or a pH adjuster was added to water and mixed to prepare the cleaning liquid compositions according to Examples 1 to 15 and Comparative Examples 1 to 5.
[0050] 2. Evaluation of cleaning ability of cleaning solution compositions for molybdenum (Mo) substrates 2.1. Preparation of CMP polishing solution Hydrogen peroxide was added to a slurry using silicon oxide (W2000-V WIN, manufactured by Cabot) to a concentration of 4.5 wt % to obtain a CMP polishing solution.
[0051] 2.2. Preparation of the substrate to be polished A molybdenum (Mo) substrate having the following configuration was prepared (ALD-Mo 30 nm / Si, manufactured by Global Net Co., Ltd.): The molybdenum (Mo) substrate was chipped to a size of 2.0 cm x 2.0 cm to obtain molybdenum (Mo) chips to be polished.
[0052] 2.3. Polishing and Cleaning Molybdenum (Mo) Chips The molybdenum (Mo) chips to be polished were polished for 30 seconds using the CMP polishing solution with a polishing machine (manufactured by MAT Corporation, model number BC-15CN). After polishing, the wafer was rinsed with ultrapure water (DIW) for 10 seconds while rotating. The chips were immersed in 100 mL of each cleaning solution composition listed in Table 1, stirred at 200 rpm, and washed for 1 minute. The molybdenum (Mo) chips after cleaning were dried with N2 blow to obtain molybdenum (Mo) chips for measurement.
[0053] 2.4. Measuring the number of defects on the surface of a molybdenum (Mo) chip The number of defects on the molybdenum (Mo) chip surface was measured by observing the surface of the molybdenum (Mo) chip at 10,000x magnification using a FE-SEM (Reegulus) and counting the number of deposits found within an area of 12.7 μm x 9.5 μm. The post-CMP residue removal rate was calculated using the following formula. The post-CMP residue removal rate for each cleaning composition is shown in Table 1 and Figures 1 and 3.
number
[0054] 3. Evaluation of the corrosiveness of cleaning solution compositions to molybdenum (Mo) 3.1. Preparation of Molybdenum (Mo) Chips A molybdenum (Mo) substrate having the following configuration was prepared (PMD-Mo 500 nm / Si, manufactured by Advanced Materials Technology Co., Ltd.): The molybdenum (Mo) substrate was chipped into 1.5 cm x 1.5 cm pieces to obtain molybdenum (Mo) chips for evaluation. 3.2. Preparation of evaluation solution The molybdenum (Mo) chips for evaluation were immersed in a 1.0 mM tetramethylhydroxyammonium hydroxide (TMAH) aqueous solution for 2 minutes, then rinsed with running ultrapure water (DIW). They were then immersed in 50 mL of each cleaning composition listed in Table 1 for 1 minute while stirring at 200 rpm. The molybdenum (Mo) chips were removed, and the cleaning compositions after immersion were used as evaluation solutions. 3.3. Etching rate measurement The molybdenum (Mo) concentration in the evaluation solution was measured using an ICP-MS (Agilent, model number: 7900). The etching rate (ER) of molybdenum (Mo) was calculated from the obtained molybdenum (Mo) concentration using the following formula. The evaluation results are shown in Table 1 and Figures 1 to 3.
number
[0055] 4. Results [Table 1] In Table 1, DEHA is N,N-diethylhydroxylamine, surfactant is naphthalenesulfonic acid formaldehyde condensate, and mTAZ is 3-mercapto-1,2,4-triazole.
[0056] The cleaning solution composition of Example 5, which contained a reducing agent, showed a post-CMP residue removal rate of 81% or more, while the cleaning solution composition of Comparative Example 3, which did not contain a reducing agent, showed a post-CMP residue removal rate of only 53% or less (FIG. 1), demonstrating that a reducing agent is effective in improving cleaning performance. Furthermore, the cleaning liquid compositions of Comparative Examples 4 and 5, although containing the same components as the cleaning liquid composition of Example 7, exhibited higher ER of molybdenum (Mo) (FIG. 2), indicating that they could not inhibit the corrosion of molybdenum (Mo) when the pH was alkaline. Furthermore, the cleaning liquid compositions of Examples 7 and 8 showed an even improved post-CMP residue removal rate compared to the cleaning liquid compositions of Examples 5 and 6 (FIG. 3), demonstrating that surfactants are effective in improving cleaning performance.
Claims
1. A cleaning liquid composition for cleaning a substrate having a molybdenum (Mo)-containing film, the cleaning liquid composition comprising one or more reducing agents and water, and having a pH of 7 or less.
2. 2. The cleaning solution composition of claim 1, wherein the reducing agent is selected from the group consisting of hydroxylamine derivatives, gallic acid, ascorbic acid, and pyrogallol.
3. 3. The cleaning liquid composition according to claim 2, wherein the hydroxylamine derivative is selected from the group consisting of N,N-diethylhydroxylamine, N-methylhydroxylamine, and N,N-dimethylhydroxylamine.
4. The cleaning liquid composition of claim 1 , further comprising one or more pH adjusters.
5. The cleaning liquid composition according to claim 4, wherein the pH adjuster is a quaternary ammonium compound or an inorganic acid.
6. 6. The cleaning liquid composition according to claim 5, wherein the quaternary ammonium compound is trimethyl-2-hydroxyethylammonium hydroxide.
7. 6. The cleaning solution composition of claim 5, wherein the inorganic acid is selected from the group consisting of nitric acid, sulfuric acid, hydrofluoric acid, and hydrochloric acid.
8. The cleaning liquid composition of claim 1 further comprising one or more surfactants.
9. The cleaning liquid composition according to claim 8, wherein the surfactant is a polysulfonic acid compound.
10. The cleaning solution composition of claim 1 further comprising one or more corrosion inhibitors.
11. The cleaning liquid composition according to claim 10, wherein the anticorrosive agent is a nitrogen-containing ring compound or a thiol compound.
12. 12. The cleaning liquid composition according to claim 11, wherein the nitrogen-containing ring compound is selected from the group consisting of 1,2,4-triazole, 3-mercapto-1,2,4-triazole, and bismuthiol.
13. The cleaning liquid composition according to claim 11, wherein the thiol compound is cysteine or thiosalicylic acid.
14. 2. The concentrate composition for the cleaning liquid composition according to claim 1, which is used to obtain the cleaning liquid composition by diluting it 10 to 1000 times.
15. A method for cleaning a substrate having a molybdenum (Mo)-containing film, comprising the step of contacting the substrate having the molybdenum (Mo)-containing film with the cleaning liquid composition of claim 1.
16. A method for producing a semiconductor substrate, comprising a step of contacting the cleaning liquid composition according to claim 1 with a substrate having a molybdenum (Mo)-containing film.
17. 17. The method for producing a semiconductor substrate according to claim 16, further comprising chemically mechanically polishing (CMP) the substrate having the molybdenum (Mo)-containing film prior to the step of contacting the substrate having the molybdenum (Mo)-containing film.
18. 17. The method for producing a semiconductor substrate according to claim 16, wherein the step of contacting the substrate having the molybdenum (Mo)-containing film is a step of cleaning the substrate having the molybdenum (Mo)-containing film.
Citation Information
Patent Citations
Cleaning composition, and method for producing semiconductor substrate
WO2023189432A1