KR102399811B1 - Post metal film chemical mechanical polishing cleaning solution - Google Patents

Abstract

The present invention relates to a cleaning liquid composition after polishing a metal film, and the cleaning liquid composition after polishing a metal film according to an embodiment of the present invention is a chelate comprising one or two or more selected from the group consisting of an organic compound and a salt compound. my; and a surfactant including a nonionic surfactant, an anionic surfactant, or both.

Description

Cleaning solution composition after metal film polishing {POST METAL FILM CHEMICAL MECHANICAL POLISHING CLEANING SOLUTION}

The present invention relates to a cleaning liquid composition after polishing a metal film, and to a cleaning liquid composition after polishing a metal film used in a cleaning process after a chemical mechanical polishing process of a wafer for semiconductor devices, and a cleaning method using the same.

Microelectronic device wafers are used to form integrated circuits. The microelectronic device wafer comprises a wafer, such as silicon, into which regions are patterned for deposition of different materials having insulating, conductive or semiconducting properties. In order to obtain accurate patterning, the excess material used to form the layers on the wafer must be removed. In addition, in order to fabricate functional and reliable circuits, it is important to prepare a flat or planar microelectronic wafer surface prior to subsequent processing. Accordingly, it is necessary to remove and/or polish certain surfaces of microelectronic device wafers.

Chemical Mechanical Polishing (CMP) is a process in which any material is removed from the surface of a microelectronic device wafer, and the surface is polished in cooperation with a chemical process such as oxidation or chelation by a physical process such as polishing. In its most basic form, CMP involves applying a slurry, eg, a solution of an abrasive and an active compound, to a polishing pad that buffs the surface of a microelectronic device wafer to achieve a removal, planarization and polishing process. In the fabrication of integrated circuits, CMP slurries should also be capable of preferentially removing films containing complex layers of metals and other materials so that highly planar surfaces can be created for subsequent lithography or patterning, etching and thin film processing. .

On the other hand, in order to remove contamination of particles, metal atoms, organic matter, etc. generated in the manufacturing process of the semiconductor device and to improve the reliability of the device, a cleaning process may be performed. However, since the cleaning solution composition used for cleaning after polishing generally has an abundance of OH- in the alkaline aqueous solution, the abrasive particles and the wafer surface are charged, making it easy to remove the abrasive particles through electrical repulsion, There is a problem in that impurities such as metal contaminants and organic residues on the wafer surface after cleaning are not effectively removed. In addition, when the pH of the cleaning liquid composition is 8 or higher, roughness tends to occur on the wafer surface due to the etching action of the basic compound. Accordingly, there is a need for a composition used in a cleaning process that can effectively remove residual particles, organic contaminants, and metal contaminants while minimizing surface damage.

The present invention is to solve the above problems, and an object of the present invention is to polish a metal film capable of removing defects, residual particles, organic contaminants and metal contaminants in a cleaning process performed after chemical mechanical polishing of a semiconductor device wafer To provide a post-cleaning solution composition and a cleaning method using the same.

However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

The cleaning solution composition after polishing a metal film according to an embodiment of the present invention includes: a chelating agent comprising one or two or more selected from the group consisting of organic compounds and salt compounds; and a surfactant including a nonionic surfactant, an anionic surfactant, or both.

According to an embodiment, the organic compound may include an organic acid including at least one carboxyl group and at least one hydroxyl group.

According to one embodiment, the organic acid comprising at least one carboxyl group and at least one hydroxyl group is citric acid, isocitric acid, oxalic acid, tartaric acid, malic acid acid), glycolic acid, gluconic acid, and lactic acid may be included in at least one selected from the group consisting of.

According to one embodiment, the organic compound may be 0.5 wt% to 5 wt% of the cleaning solution composition after polishing the metal film.

According to one embodiment, the salt compound is sodium citrate, potassium citrate, ammonium citrate, ammonium hydrogen citrate, sodium phosphate (Sodium) phosphate), potassium phosphate, ammonium phosphate, and derivatives thereof may include at least one selected from the group consisting of.

According to an embodiment, the salt compound may be present in an amount of 3 wt% to 10 wt% of the cleaning solution composition after polishing the metal film.

According to one embodiment, the nonionic surfactant, Gemini surfactant, ethoxylated acetylenic diol, polyoxyalkylene ester, polyoxyalkylene fatty acid ester, polyoxyethylene alkyl It may include at least one selected from the group consisting of ether, polyoxypropylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, and polyoxyethylene polyoxypropylene alkyl aryl ether.

According to an embodiment, the nonionic surfactant may include a hydrocarbon chain having 4 to 20 carbon atoms.

According to one embodiment, the Gemini surfactant may have multiple bonds (eg, carbon-carbon double bond, carbon-carbon triple bond) in the main chain.

According to an embodiment, the gemini surfactant may include the following Chemical Formula 1, the following Chemical Formula 2, or both.

[Formula 1]

[Formula 2]

In Formulas 1 and 2, R ₁ to R ₆ are, respectively, hydrogen, halogen, linear or branched alkyl group having 1 to 20 carbon atoms, hydroxy group (-OH), and 1 to 5 carbon atoms oxyalkylene group, -(R')m-(R'')n copolymer, -OA, and -R'-A (R' and R'' are each selected from an oxyalkylene group having 1 to 5 carbon atoms) and R' and R'' are different from each other, A is an anionic group, and m and n are, respectively, selected from 1 to 100).

According to an embodiment, in Formula 1 and Formula 2, R ₁ , R ₂ , R ₃ and R ₄ are each selected from hydrogen, a linear or branched C1-C20 alkyl group, R ₅ and R ₆ is, respectively, a hydroxy group (-OH), an oxyalkylene group having 1 to 5 carbon atoms, -(R')m-(R'')n copolymer, -OA, and -R'-A (R' and R'' is each selected from an oxyalkylene group having 1 to 5 carbon atoms, R' and R'' are different from each other, A is selected from a sulfone group, a sulfuric acid group, a phosphoric acid group, and a carboxyl group, m and n are , each selected from 1 to 100) may be selected.

According to an embodiment, in Formula 1 and Formula 2, R ₅ and R ₆ are, respectively, an oxyalkylene group having 2 to 4 carbon atoms, -(R')m-(R'')n copolymer, -OA , and -R'-A (R' and R'' are each selected from an oxyalkylene group having 2 to 4 carbon atoms, A is selected from PO ₃ ^2- , SO ₃ ^- , COO ^- and CH ₃ COO ^- , m and n may each be selected from 1 to 20).

According to one embodiment, the nonionic surfactant may be 1 wt% or less of the cleaning solution composition after polishing the metal film.

According to an embodiment, the anionic surfactant may include a carboxyl group, a sulfonic acid group, or both.

According to one embodiment, the anionic surfactant is, polyacrylic acid, polyacrylic acid ammonium salt, polymethacrylic acid, polymethacrylic acid ammonium salt, polymaleic acid, polyacrylate, polymethacrylate, polymethylmethacrylate, poly Acrylamide, acrylic acid/styrene copolymer, acrylic acid/sulfonic acid copolymer, acrylic acid/malonic acid copolymer, acrylic acid/acrylate copolymer, acrylamide/acrylic acid copolymer, acrylamide/sulfonic acid copolymer, polystyrenesulfonic acid, polyvinylsulfonic acid, Polytoluenesulfonic acid, alkylbenzenesulfonic acid, alkylsulfonic acid, alkanesulfonic acid, alkylarylsulfonic acid, alpha-olefinsulfonic acid, dodecylbenzenesulfonic acid, octylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecanesulfonic acid, tetradecylbenzenesulfonic acid, alkylbenzenesulfonic acid, alkyl It may include at least one selected from the group consisting of diphenyl ether disulfonic acid, polystyrene sulfonate, polysodium styrene sulfonate, dodecylbenzene sulfonate, and salts thereof.

According to one embodiment, the anionic surfactant may be 1 wt% to 5 wt% of the cleaning solution composition after polishing the metal film.

According to an embodiment, it further comprises a; Amine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, ammonium hydrogencarbonate, ammonium carbonate, potassium hydrogencarbonate, potassium carbonate , may be one comprising at least one selected from the group consisting of sodium hydrogen carbonate and sodium carbonate.

According to one embodiment, the pH of the cleaning solution composition after polishing the metal film may be 4 to 8.

According to an embodiment, the cleaning solution composition after polishing the metal film includes at least one film selected from the group consisting of a tungsten film, a silicon oxide film, a silicon nitride film, a titanium film, and a titanium nitride film after polishing the tungsten film. It can be to remove defects, residues and contaminants from the phase.

According to an embodiment, when the metal film is polished with the cleaning solution composition, the defect reduction rate for the silicon nitride film may be 80% or more, and the defect reduction rate for the silicon oxide film may be 80% or more.

A cleaning method according to another embodiment of the present invention is to clean a semiconductor device wafer after chemical mechanical polishing of the semiconductor device wafer using the cleaning solution composition after polishing a metal film according to an embodiment of the present invention.

The cleaning solution composition after polishing a metal film according to an aspect of the present invention cleans the wafer surface for a semiconductor device after chemical mechanical polishing of the metal film to effectively improve defects of the nitride film and the oxide film, and the metal film, for example, the tungsten film It can prevent corrosion. In addition, it is possible to sufficiently remove contaminants such as abrasive particles, organic matter, and impurities remaining after polishing the semiconductor wafer.

According to the cleaning method according to another aspect of the present invention, it is possible to easily remove defects in a subsequent cleaning process by changing the surface properties of the wafer for semiconductor devices after chemical mechanical polishing.

1 is a graph measuring galvanic corrosion of a substrate treated with 2% NH ₄ OH and a cleaning solution composition after polishing a metal film of Example 8 of the present invention.
2 is a graph showing the etching rates of tungsten (W), titanium nitride (TiN), and titanium (Ti) in the cleaning process of the cleaning solution composition after polishing the metal film of Example 8 of 2% NH ₄ OH and of the present invention.
3 shows UV-vis spectra according to Fe, the cleaning solution alone, and the cleaning solution + Fe.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, since various changes may be made to the embodiments, the scope of the patent application is not limited or limited by these embodiments. It should be understood that all modifications, equivalents and substitutes for the embodiments are included in the scope of the rights.

The terms used in the examples are used for the purpose of description only, and should not be construed as limiting. The singular expression includes the plural expression unless the context clearly dictates otherwise. In this specification, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, component, part, or a combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiment belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

In addition, in the description with reference to the accompanying drawings, the same components are given the same reference numerals regardless of the reference numerals, and the overlapping description thereof will be omitted. In describing the embodiment, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the embodiment, the detailed description thereof will be omitted.

Hereinafter, the cleaning liquid composition after polishing the metal film of the present invention will be described in detail with reference to Examples and drawings. However, the present invention is not limited to these examples and drawings.

The cleaning solution composition after polishing a metal film according to an embodiment of the present invention includes: a chelating agent comprising one or two or more selected from the group consisting of organic compounds and salt compounds; and a surfactant including a nonionic surfactant, an anionic surfactant, or both.

In the cleaning solution composition after metal film polishing according to an embodiment of the present invention, corrosion does not occur by skipping the dHF (Diluted HF) cleaning process after chemical mechanical polishing of a semiconductor device wafer and performing brush cleaning. It is easy to remove organic matter and particles remaining on the surface. In addition, it is possible to effectively improve the defects of the nitride film and the oxide film, and to prevent corrosion of a metal film, for example, a tungsten film, while removing organic substances and contaminants from the surface.

As a specific process, a Diluted HF (dHF) 1% cleaning process may be skipped as a process after chemical mechanical polishing of a wafer for semiconductor devices, followed by a chemical cleaning process, a DIW cleaning process, and a drying process.

According to one embodiment, the chelating agent serves to prevent redeposition of the removed metal to the semiconductor surface, thereby increasing the removal effect of the abrasive particles, metal impurities, etc. remaining on the wafer for semiconductor devices .

In one embodiment of the present invention, the chelating agent may provide a cleaning effect of abrasive particles, organic matter, impurities, etc. remaining after the polishing process while having a function of a pH buffer in the cleaning solution composition after polishing the metal film.

According to an embodiment, the organic compound may include an organic acid including at least one carboxyl group and at least one hydroxyl group.

According to one embodiment, the organic acid comprising at least one carboxyl group and at least one hydroxyl group is citric acid, isocitric acid, oxalic acid, tartaric acid, malic acid ( malic acid), glycolic acid (glycolic acid), gluconic acid (gluconic acid) and lactic acid (lactic acid) may include at least one selected from the group consisting of.

According to one embodiment, the organic compound may be 0.5 wt% to 5 wt% of the cleaning solution composition after polishing the metal film. If the organic compound is less than 0.5% by weight of the cleaning solution composition after polishing the metal film, the solubility for metal oxides tends to be low, and when it exceeds 5% by weight, the cleaning liquid composition corrodes metal parts such as metal wiring after polishing the metal film Or it may be dissolved.

According to one embodiment, the salt compound is sodium citrate, potassium citrate, ammonium citrate, ammonium hydrogen citrate, sodium phosphate (Sodium) phosphate), potassium phosphate, ammonium phosphate, and derivatives thereof may include at least one selected from the group consisting of. The organic salt may include all of a monobasic, dibasic, or tribasic structure.

According to an embodiment, the salt compound may be present in an amount of 3 wt% to 10 wt% of the cleaning solution composition after polishing the metal film. When the salt compound is less than 3% by weight of the cleaning solution composition after polishing the metal film, the solubility for metal oxide tends to decrease, and when it exceeds 10% by weight, the cleaning liquid composition corrodes metal parts such as metal wiring after polishing the metal film Or it may be dissolved.

As an example of the present invention, the nonionic surfactant is easy to remove organic matter and improves cleaning and defects on the hydrophobic film. Since nonionic surfactants are highly hydrophilic and have properties of being well soluble in water, handling is easy when using them.

According to one embodiment, the nonionic surfactant, Gemini surfactant, ethoxylated acetylenic diol, polyoxyalkylene ester, polyoxyalkylene fatty acid ester, polyoxyethylene alkyl It may include at least one selected from the group consisting of ether, polyoxypropylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, and polyoxyethylene polyoxypropylene alkyl aryl ether.

According to one embodiment, the nonionic surfactant may include a hydrocarbon chain having 4 to 20 carbon atoms.

According to one embodiment, the Gemini surfactant has multiple bonds (eg, carbon-carbon double bond, carbon-carbon triple bond) in the main chain, and improves not only foaming by low foaming property, but also , it is possible to improve the cleaning effect by improving the rapid surface adsorption capacity and surface tension.

According to an embodiment, the gemini surfactant may include the following Chemical Formula 1, the following Chemical Formula 2, or both.

[Formula 1]

[Formula 2]

In Formulas 1 and 2, R ₁ to R ₆ are, respectively, hydrogen, halogen, linear or branched alkyl group having 1 to 20 carbon atoms, hydroxy group (-OH), and 1 to 5 carbon atoms an oxyalkylene group, -(R')m-(R'')n copolymer, -OA, and -R'-A.

Here, R' and R'' are each selected from an oxyalkylene group having 1 to 5 carbon atoms, R' and R'' are different from each other, A is an anionic group, and m and n are each, It may be selected from 1 to 100.

According to one embodiment, the gemini surfactant may include a hydrophilic group or a hydrophilic moiety and a hydrophobic group or a hydrophobic group in one molecule, preferably at least two hydrophilic groups and two It may include more than one hydrophobic group. That is, the gemini surfactant exhibits a lower CMC (critical micelle concentration) than a linear surfactant (a linear form at the same number of carbon atoms), so it can be rapidly adsorbed to the surface even at a low concentration to lower the surface tension, and the hydrophobic group Because the hydrophobic group exists in the branched form, it not only maintains low surface tension with low foaming properties, but also structurally adsorbs to the surface quickly, so that not only the static surface tension but also the dynamic surface tension can be lowered.

For example, in Formula 1 and Formula 2, R ₁ , R ₂ , R ₃ and R ₄ are, respectively, hydrogen, linear or branched carbon number of 1 to 20; 1 to 15 carbon atoms; Or it may be selected from an alkyl group having 1 to 12 carbon atoms.

For example, in Formula 1 and Formula 2, R ₅ and R ₆ are, respectively, a hydroxyl group (-OH), an oxyalkylene group having 1 to 5 carbon atoms, -(R')m-(R'') n copolymer, -OA, and -R'-A.

Here, R' and R'' are each selected from an oxyalkylene group having 1 to 5 carbon atoms, and R' and R'' may be different from each other.

A is an anionic group, and may be selected from, for example, a sulfone group, a sulfuric acid group, a phosphoric acid group, and a carboxyl group.

m and n are, respectively, 1 to 100; 1 to 50; or a rational number selected from 1 to 20 and excluding negative values.

Preferably, R ₅ and R ₆ are each selected from an oxyalkylene group having 2 to 4 carbon atoms, -(R')m-(R'')n copolymer, -OA, and -R'-A, wherein R' and R'' are each selected from an oxyalkylene group having 2 to 4 carbon atoms, A is selected from PO ₃ ^2- , SO ₃ ^- , COO ^- and CH ₃ COO ^- , m and n are each, It may be selected from 1 to 20.

According to one embodiment, the nonionic surfactant may be 1 wt% or less, preferably 0.05 wt% to 0.6 wt% of the cleaning solution composition after polishing the metal film. When the nonionic surfactant is more than 1% by weight of the cleaning solution composition after polishing the metal film, it is not possible to effectively clean the polishing fine particles, metal impurities, and the like, and further effects are not obtained.

As an example of the present invention, the anionic surfactant is easy to remove residual particles, impurities, etc., and improves the cleaning and defects of hydrophilic films such as silicon nitride film and silicon oxide film.

According to an embodiment, the anionic surfactant may include a carboxyl group, a sulfonic acid group, or both.

According to one embodiment, the anionic surfactant is, polyacrylic acid, polyacrylic acid ammonium salt, polymethacrylic acid, polymethacrylic acid ammonium salt, polymaleic acid, polyacrylate, polymethacrylate, polymethylmethacrylate, poly Acrylamide, acrylic acid/styrene copolymer, acrylic acid/sulfonic acid copolymer, acrylic acid/malonic acid copolymer, acrylic acid/acrylate copolymer, acrylamide/acrylic acid copolymer, acrylamide/sulfonic acid copolymer, polystyrenesulfonic acid, polyvinylsulfonic acid, Polytoluenesulfonic acid, alkylbenzenesulfonic acid, alkylsulfonic acid, alkanesulfonic acid, alkylarylsulfonic acid, alpha-olefinsulfonic acid, dodecylbenzenesulfonic acid, octylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecanesulfonic acid, tetradecylbenzenesulfonic acid, alkyldiphenyl ether di It may include at least one selected from the group consisting of sulfonic acid, polystyrenesulfonate, polysodium styrenesulfonate, dodecylbenzenesulfonate, and salts thereof.

According to one embodiment, the anionic surfactant may be 1 wt% to 5 wt% of the cleaning solution composition after polishing the metal film. When the amount of the anionic surfactant is less than 1% by weight, the decontamination ability of the metal film may not be exhibited, and when the amount of the anionic surfactant exceeds 5% by weight of the cleaning solution composition after polishing the metal film, the decontamination ability of the semiconductor film cannot be exhibited, and further effects are Since it is not obtained, it is not preferable also from an economic point of view.

According to an embodiment, it further comprises a; Amine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, ammonium hydrogencarbonate, ammonium carbonate, potassium hydrogencarbonate, potassium carbonate , may be one comprising at least one selected from the group consisting of sodium hydrogen carbonate and sodium carbonate.

According to one embodiment, the pH of the cleaning solution composition after polishing the metal film may be 4 to 8. When included in the pH range, when the chemical mechanical polishing (CMP) wafer is treated with the cleaning solution composition after polishing the metal film, it is possible to provide an excellent cleaning effect and low defects in a subsequent cleaning process. In addition, it is possible to sufficiently remove contaminants such as abrasive particles, organic matter, and impurities remaining after polishing the semiconductor wafer.

In one aspect, the cleaning solution composition after polishing the metal film may include a solvent, and the solvent may include water and/or an organic solvent. After polishing the metal film, water in the cleaning liquid composition serves to dissolve or disperse other components in the cleaning liquid composition. It is preferable that water does not contain as much as possible the impurity which inhibits the action|action of another component. Specifically, ion-exchanged water from which foreign substances are removed through a filter after removing impurity ions using an ion-exchange resin, or pure water, ultrapure water, deionized water or distilled water is preferable.

According to an embodiment, the cleaning solution composition after polishing the metal film includes at least one film selected from the group consisting of a tungsten film, a silicon oxide film, a silicon nitride film, a titanium film, and a titanium nitride film after polishing the tungsten film. It can be to remove defects, residues and contaminants from the phase.

According to an embodiment, when the metal film is polished with the cleaning solution composition, the defect reduction rate for the silicon nitride film may be 80% or more, and the defect reduction rate for the silicon oxide film may be 80% or more.

A cleaning method according to another embodiment of the present invention is to clean a semiconductor device wafer after chemical mechanical polishing of the semiconductor device wafer using the cleaning solution composition after polishing a metal film according to an embodiment of the present invention.

In the present invention, by including the nonionic surfactant and the anionic surfactant at the same time, surface defects can be remarkably lowered when the metal film, for example, the tungsten film is polished and then cleaned with the cleaning solution composition after polishing the metal film of the present invention. Preferably, defects on the surfaces of the nitride film and the oxide film can be reduced.

On one side, when cleaning with a cleaning solution composition after polishing the metal film, defects on the silicon nitride film are reduced by 80% based on defects when 1% hydrofluoric acid cleaning and NH ₄ OH cleaning are performed. above, the defect reduction rate of the oxide film may be 80% or more based on the defects when 1% hydrofluoric acid cleaning and NH ₄ OH cleaning are performed.

The cleaning solution composition after polishing the metal film of the present invention may be cleaned by directly contacting the wafer for semiconductor devices.

In one aspect, the residue comprises particles from the CMP polishing slurry, chemicals present in the CMP polishing slurry, reaction byproducts of the CMP polishing slurry, carbon-enriched particles, polishing pad particles, brush unloading particles, equipment material of the constituent particles, It may include a material selected from the group consisting of metals, metal oxides, and combinations thereof.

The cleaning solution composition after metal film polishing according to an embodiment of the present invention changes the surface properties by chemically buffing the surface of the semiconductor device wafer after chemical mechanical polishing by including a nonionic surfactant and an anionic surfactant, By improving the wettability to the wafer surface by the surfactant and anionic surfactant, cleaning and defect removal in the subsequent cleaning process can be facilitated.

In another aspect of the present invention, there is provided a cleaning method for cleaning the semiconductor device wafer after chemical mechanical polishing of the semiconductor device wafer using the cleaning solution composition after metal film polishing according to one aspect of the present invention.

The cleaning liquid composition after metal film polishing of the present invention can be used in the same apparatus and conditions as those used in a normal wafer cleaning process. When the wafer is cleaned by the surface treatment method of the present invention, the temperature at the time of using the cleaning liquid composition after polishing the metal film is not particularly limited, but may be 5°C to 60°C.

The cleaning of the wafer by the cleaning method of the present invention may be a surface treatment for changing the surface characteristics of the polished wafer, or may be included in a cleaning process for cleaning the polished wafer. The cleaning time is generally performed for several seconds to several minutes, and may be performed within 1 second to 10 minutes.

Subsequent cleaning may be further included after the cleaning of the present invention. Subsequent cleaning can be applied to any general cleaning method. For example, dHF cleaning, hydrofluoric acid cleaning, SC1 cleaning, cleaning using other commercially available cleaning solutions, etc. may be used alone or in combination of two or more. In the case of proceeding with the cleaning of the present invention, even if the conventionally used dHF 1% cleaning process is skipped or simplified, an equivalent or more effect can be exhibited.

According to the cleaning method of the present invention, it is possible to easily remove defects in a subsequent cleaning process by changing the surface properties of a wafer for semiconductor devices after chemical mechanical polishing.

Hereinafter, the present invention will be described in detail with reference to the following Examples and Comparative Examples. However, the technical spirit of the present invention is not limited or limited thereto.

[Comparative Example 1]

Among the chelating agents, 1.5 wt% of citric acid as an organic compound, 1.2 wt% of polystyrene sulfonate as an anionic surfactant, and monoethanolamine as a pH adjuster were added to prepare a cleaning solution composition having a pH of 7.

[Example 1]

A composition having a pH of 7 was prepared by adding 1.5 wt% of gluconic acid as an organic compound in the chelating agent, 6 wt% of ammonium phosphate as a salt compound, 1.2 wt% of polystyrene sulfonate as an anionic surfactant, and monoethanolamine as a pH adjusting agent.

[Example 2]

In Example 1, a cleaning solution composition after polishing the metal film was prepared in the same manner as in Example 1, except that ammonium citrate was added as a salt compound in the chelating agent and anionic polyacrylate was added as a surfactant.

[Example 3]

A composition having a pH of 6 by adding 1.5 wt% of lactic acid as an organic compound in the chelating agent, 6 wt% of ammonium hydrogen citrate as a salt compound, 1.2 wt% of polymethylmethacrylate as an anionic surfactant, and monoethanolamine as a pH adjuster was prepared.

[Example 4]

In Example 3, 0.2 wt% of ethoxylated acetylenic diol as a nonionic surfactant was additionally added and the pH was adjusted to 7, except that the cleaning solution composition was prepared after polishing the metal film in the same manner as in Example 3 prepared.

[Example 5]

In Example 4, as in Example 4, except that malic acid was added as an organic compound in the chelating agent, an acrylate copolymer was added instead of polymethylmethacrylate as an anionic surfactant, and the pH was adjusted to 6. After polishing the metal film, a cleaning solution composition was prepared.

[Example 6]

Polishing the metal film in the same manner as in Example 1, except that in Example 1, ammonium hydrogen citrate was added instead of ammonium phosphate as a salt compound in the chelating agent, and an ethoxylated acetylenic diol was further added as a nonionic surfactant. After that, a cleaning solution composition was prepared.

[Example 7]

In the chelating agent, 1.5 wt% of citric acid as an organic compound, 6 wt% of ammonium hydrogen citrate as a salt compound, 1.2 wt% of polyacrylate as a surfactant and 0.2 wt% of an ethoxylated acetylenic diol as a nonionic surfactant, as a pH adjuster Monoethanolamine was added to prepare a composition having a pH of 6.

[Example 8]

In Example 7, a cleaning solution composition after polishing the metal film was prepared in the same manner as in Example 7, except that gluconic acid was added as an organic compound and the pH was adjusted to 7.

[Example 9]

In Example 7, a cleaning solution composition after polishing the metal film was prepared in the same manner as in Example 7, except that polyoxyalkylene ester was added instead of ethoxylated acetylene-based diol as a nonionic surfactant and the pH was adjusted to 7. .

[Example 10]

In Example 8, a cleaning solution composition after polishing the metal film was prepared in the same manner as in Example 8, except that polyoxyethylene polypropylene alkyl ether was added as a nonionic surfactant.

Wafer Defect Measurement

A nitride film wafer, an oxide film wafer, and a tungsten film wafer were subjected to chemical mechanical polishing for 20 seconds at 1 psi pressure and 200 ml conditions using colloidal silica slurry (pH 2) having abrasive particles having a diameter of 130 nm. After polishing the polished nitride film wafer, oxide film wafer, and tungsten film wafer with the metal film according to Examples 1 to 3 and Comparative Examples 1 to 4, the wafer was cleaned by brush cleaning twice for 30 seconds and 20 seconds using the cleaning solution composition. Surface cleaning was performed.

Thereafter, defects were confirmed for each of the nitride film wafer, the oxide film wafer, and the tungsten film wafer using defect measuring equipment (KLA-Tencor).

Defect removal rate calculation: Defect removal rate (%) = {1-(number of defects/number of defects in Comparative Example 1)} * 100

[Defect Evaluation Criteria]

After cleaning with 1% hydrofluoric acid for 10 seconds and cleaning with 2% NH ₄ OH solution for 30 seconds, the defects measured for each of the nitride film wafer, the oxide film wafer and the tungsten film wafer were referenced. There were 11,244 defects (≥ 52 nm) in nitride wafers, 4,730 defects (≥ 63 nm) in oxide wafers, and 72 defects (≥ 65 nm) in tungsten wafers.

Defects when the cleaning process was performed using the cleaning solution composition after polishing the metal film of Examples 1 to 3 and the cleaning solution composition of Comparative Examples 1 to 4 of the present invention were, compared to the reference wafer defects, the defect reduction rate (%) indicated as

Table 1 below summarizes specific compositions of the cleaning solution composition after polishing the metal film of Examples 1 to 3 and the cleaning solution composition of Comparative Examples 1 to 4. Table 2 below shows the types of chelating agents symbolized by abbreviations in Table 1.

pH Kinds Defect Removal Rate (%) Chelating agent 1
(abandonment
compound) chelating agent 2
(salt compound) interface
activator Nitride Oxide W (≥52 nm) (≥63 nm) (≥65 nm) standard 1% hydrofluoric acid cleaning + 2% NH4OH cleaning 11,244 0.0% 4,730 0.0% 72 0.0% comparative example
One 7 A1 - C1 115,055 -923.3% 378 92.0% - - Example
One 7 A2 B1 C1 4,726 58.0% 227 95.2% 49 31.9% Example
2 7 A2 B2 C2 3,106 72.4% 319 93.3% 23 68.1% Example
3 6 A3 B3 C4 2,980 73.5% 412 91.3% 62 13.9% Example
4 7 A3 B3 C4+C6 1,657 85.3% 234 95.1% 71 1.4% Example
5 6 A4 B3 C5+C6 2,105 81.3% 356 92.5% 48 33.3% Example
6 7 A2 B3 C1+C6 2,254 80.0% 218 95.4% 28 61.1% Example
7 6 A1 B3 C2+C6 1,141 89.9% 633 86.6% 68 5.6% Example
8 7 A2 B3 C2+C6 1,057 90.6% 420 91.1% 65 9.7% Example
9 7 A1 B3 C2+C7 1,352 88.0% 492 89.6% 62 13.9% Example
10 7 A2 B3 C2+C8 1,826 83.8% 350 92.6% 60 16.7%

No Chelating agent 1 (organic compound) A1 Citric acid A2 Gluconic acid A3 lactic acid A4 malic acid No Chelating agent 2 (salt compound) B1 Ammonium phosphate B2 Ammonium citrate B3 Ammonium hydrogen citrate No Surfactants C1 Polysthrene sulfonate C2 Polyacrylate C3 Polyacrylic acid C4 Polymethylmethacrylate C5 Acrylate copolymer C6 ethoxylated acetylenic diol C7 Polyoxyalkylene ester C8 Polyoxyethylene polypropylene alkyl ether

Referring to Table 1, it can be seen that when an organic compound and a salt compound are used together as a chelating agent and an anionic surfactant is included, the level of defects in the nitride film is improved. In particular, it was found that the nitride film defect level was further improved when the nonionic surfactant was further included as the surfactant.

After polishing the metal film of Examples 1 to 8, the cleaning solution composition showed excellent defect reduction rates in each of the nitride film and the oxide film, and the tungsten film was found to be equal to or higher than the standard.

In the present invention, it can be seen that defects can be easily removed by cleaning the surface of the wafer after tungsten polishing using a cleaning solution composition after polishing a metal film including a chelating agent, a nonionic surfactant and an anionic surfactant.

Galvanic Corrosion Assessment

VERSA STAT3 was used for galvanic corrosion evaluation analysis equipment.

The analysis conditions are as follows.

- Initial Potential (V): -1

- Final Potential (V): 2

- Step Height (mV): 20

- Step Time (s): 1

1 is a graph measuring galvanic corrosion of a substrate treated with a cleaning solution composition after polishing a metal film of Example 8 of 2% NH ₄ OH and of the present invention, and Table 3 below is 2% NH ₄ OH and the present invention The corrosion potential (E _corr ) and current density (I _corr ) measured by galvanic corrosion of the substrate treated with the cleaning solution composition after polishing the metal film of Example 8 are shown.

clogging 2% NH ₄ OH Example 8 cleaning solution I _corr (nA) E _corr (mV) I _corr (nA) E _corr (mV) TiN 2058 -409.1 315.14 -218.85 W 853.452 -516.86 719.12 -288.34

Galvanic corrosion occurs between titanium nitride (TiN) and tungsten (W), and when cleaning with 2% NH ₄ OH, the potential difference between titanium nitride (TiN) and tungsten (W) is as high as 107 mV. , it can be seen that when cleaning with the cleaning solution of the present invention, the potential difference between titanium nitride (TiN) and tungsten (W) is lowered to 69 mV.

Therefore, it can be seen that the cleaning solution composition after polishing the metal film of the present invention is excellent in the effect of preventing galvanic corrosion. When two metals are in contact with an electrolyte solution, if the potential difference between the two metals is small, electron movement is suppressed and corrosion can be prevented.

Etch rate evaluation

2 is a graph showing the etching rates of tungsten (W), titanium nitride (TiN), and titanium (Ti) in the cleaning process of the cleaning solution composition after polishing the metal film of Example 3 of 2% NH ₄ OH and the present invention. Referring to FIG. 2 , it can be seen that the etching rate of tungsten (W) is 0.62 Å/min when cleaning with 2% NH ₄ OH, and the cleaning solution composition is used after polishing the metal film of Example 3 of the present invention A very low value of 0.04 Å/min was confirmed when washing was performed. It can be seen that cleaning is performed without etching of tungsten, which is effective in preventing problems that may occur in subsequent steps.

Chelating Performance Evaluation

A UV-Visible Spectrometer (UV2600) equipment was used as an etch rate evaluation analysis equipment.

The analysis method is specifically, ferric nitrate (Fe(NO ₃ ) ₂ ) 0.01 wt% aqueous solution (expressed as Fe), the cleaning solution composition after polishing the metal film of Example 8 of the present invention (represented by the cleaning solution alone) and this After polishing the metal film of Example 8 of the present invention, a mixture of 0.01 wt% aqueous solution of ferric nitrate (Fe(NO ₃ ) ₂ ) in the cleaning solution composition (represented as cleaning solution + Fe) is combined using a UV Spectrometer peak combined was observed for complex pick.

3 shows UV-vis spectra according to Fe, the cleaning solution alone, and the cleaning solution + Fe. In the case of Fe-only peak point, it occurs around 300 nm, and when it is mixed with a washing solution and analyzed the UV-vis spectrum, it can be confirmed that the Fe peak point is shifted to around 250 nm and changed. This is because the absorbance was changed by chelating when mixed with the cleaning solution, and the cleaning solution without a change in the UV peak showed relatively poor cleaning ability.

Referring to FIG. 3 , a chelating peak appears in Fe and the washing solution + Fe, but the chelating peak does not appear in the range of 250 nm to 300 nm in the washing solution alone. As such, as a result of measuring the performance through the chelate index, it can be confirmed that contamination of metal ions on the surface can be effectively removed after cleaning of the cleaning solution + Fe.

As a result of measuring performance through galvanic corrosion evaluation, etch rate evaluation, and chelating performance evaluation as described above, it was confirmed that the cleaning solution composition of the present invention exhibited excellent properties after polishing the metal film.

As described above, although the embodiments have been described with reference to the limited drawings, those skilled in the art may apply various technical modifications and variations based on the above. For example, even if the described techniques are performed in an order different from the described method, and/or the described components are combined or combined in a different form from the described method, or are substituted or substituted by other components or equivalents, appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (20)

a chelating agent comprising one organic compound and one salt compound; and
surfactants including nonionic surfactants and anionic surfactants;
including,
The organic compound comprises an organic acid comprising at least one carboxyl group and at least one hydroxyl group,
The organic acid comprising at least one carboxyl group and at least one hydroxyl group is citric acid, isocitric acid, oxalic acid, tartaric acid, malic acid, glycolic acid (glycolic acid), including at least one selected from the group consisting of gluconic acid (gluconic acid) and lactic acid (lactic acid),
The salt compound is sodium citrate, potassium citrate, ammonium citrate, ammonium hydrogen citrate, sodium phosphate, potassium phosphate ( potassium phosphate), ammonium phosphate, and at least one selected from the group consisting of derivatives thereof,
After polishing the tungsten film, to remove defects, residues and contaminants on the surface of a semiconductor device wafer comprising at least one film selected from the group consisting of a tungsten film, a silicon oxide film, a silicon nitride film, a titanium film, and a titanium nitride film,
The anionic surfactant includes at least one selected from the group consisting of polyacrylate, polymethyl methacrylate and acrylate copolymer,
The nonionic surfactant includes an ethoxylated acetylenic diol, a polyoxyalkylene ester, or both,
having a pH of 6 to 7,
A cleaning solution composition after polishing the metal film.
delete delete According to claim 1,
The organic compound is 0.5 wt% to 5 wt% of the cleaning solution composition after polishing the metal film,
A cleaning solution composition after polishing the metal film.
delete According to claim 1,
The salt compound will be 3% to 10% by weight of the cleaning solution composition after polishing the metal film,
A cleaning solution composition after polishing the metal film.
delete delete delete delete delete According to claim 1,
The nonionic surfactant is 1 wt% or less of the cleaning solution composition after polishing the metal film,
A cleaning solution composition after polishing the metal film.
According to claim 1,
The anionic surfactant will include a carboxyl group, a sulfonic acid group, or both,
A cleaning solution composition after polishing the metal film.
According to claim 1,
The anionic surfactant is
The anionic surfactant is polyacrylic acid, polyacrylic acid ammonium salt, polymethacrylic acid, polyammonium methacrylic acid salt, polymaleic acid, polyacrylate, polymethacrylate, polymethylmethacrylate, polyacrylamide, acrylic acid / styrene Copolymer, acrylic acid/sulfonic acid copolymer, acrylic acid/malonic acid copolymer, acrylic acid/acrylate copolymer, acrylamide/acrylic acid copolymer, acrylamide/sulfonic acid copolymer, polystyrenesulfonic acid, polyvinylsulfonic acid, polytoluenesulfonic acid, alkylbenzene Sulfonic acid, alkylsulfonic acid, alkanesulfonic acid, alkylarylsulfonic acid, alpha-olefinsulfonic acid, dodecylbenzenesulfonic acid, octylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecanesulfonic acid, tetradecylbenzenesulfonic acid, alkylbenzenesulfonic acid, alkyldiphenyletherdisulfonic acid, Which comprises at least one selected from the group consisting of polystyrene sulfonate, polysodium styrene sulfonate, dodecylbenzene sulfonate, and salts thereof,
A cleaning solution composition after polishing the metal film.
According to claim 1,
The anionic surfactant is 1 wt% to 5 wt% of the cleaning solution composition after polishing the metal film,
A cleaning solution composition after polishing the metal film.
According to claim 1,
pH adjusters;
further comprising,
The pH adjusting agent,
Monoethanolamine, diethanolamine, triethanolamine, methylethanolamine, ethylethanolamine, N-amino-N-propanol, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, Ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, ammonium hydrogencarbonate, ammonium carbonate, potassium hydrogencarbonate, potassium carbonate, sodium hydrogencarbonate and containing at least one selected from the group consisting of sodium carbonate sign,
A cleaning solution composition after polishing the metal film.
delete delete According to claim 1,
When the metal film is polished and then cleaned with the cleaning solution composition, the defect reduction rate for the silicon nitride film is 80% or more, and the defect reduction rate for the silicon oxide film is 80% or more,
A cleaning solution composition after polishing the metal film.
The method for cleaning a semiconductor device wafer after chemical mechanical polishing of the semiconductor device wafer using the cleaning solution composition after polishing the metal film of claim 1,
cleaning method.

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