Polishing composition for semiconductor processing and method for polishing substrates using the same

Abstract

To provide a polishing composition for semiconductor processes that, when applied to polishing of a substrate containing two or more types of films, the polishing composition exhibiting a polishing speed above a certain level and further embodying a smooth surface to be polished.SOLUTION: A polishing composition contains abrasive particles, a polyoxyalkylene surfactant, and a skew inhibitor of the following chemical formula. The HLB (Hydrophile-Lipophile Balance) value of the polyoxyalkylene surfactant is 13 or higher. In the chemical formula, R1 is H, a methyl group or an ethyl group, and R2, R3 and R4 are independently a methyl group or an ethyl group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present embodiment relates to a polishing composition for semiconductor processing and a method for polishing a substrate using the same. [Background technology]

[0002] As semiconductor devices become smaller and denser, ever-finer pattern formation technologies are being used. As a result, the surface structure of semiconductor devices becomes more complex, and the steps in interlayer films become larger. In manufacturing semiconductor devices, a chemical mechanical polishing (hereinafter referred to as "CMP") process is used as a planarization technology to remove steps in specific films formed on a substrate.

[0003] In the CMP process, a substrate is pressed and rotated while a slurry is applied to a polishing pad to polish the surface. The target to be planarized varies depending on the process stage, and the properties of the slurry used at this time also vary.

[0004] Polishing after the metal wiring is formed must maintain a sufficient polishing rate and polishing speed while minimizing dishing and the like.

[0005] The above-mentioned background art is technical information that the inventor possessed for the purpose of deriving the present invention or that he acquired in the process of deriving the present invention, and is not necessarily publicly known art that was made public to the general public prior to the filing of this application. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Korean Patent No. 10-0516886 [Patent Document 2] Korean Patent No. 10-1395866 Summary of the Invention [Problem to be solved by the invention]

[0007] The purpose of the embodiment is to provide a polishing composition for semiconductor processing that can provide a smoother polished surface while maintaining a polishing rate above a certain level when polishing the surface of a substrate having two or more films. [Means for solving the problem]

[0008] A polishing composition for semiconductor processing according to one embodiment of the present specification includes abrasive particles, a polyoxyalkylene surfactant, and a skew inhibitor represented by the following Chemical Formula 1:

[0009] [ka]

[0010] In the above formula 1, R1 is H, a methyl group, or an ethyl group, and R2, R3, and R4 are each independently a methyl group or an ethyl group.

[0011] The polyoxyalkylene surfactant has an HLB (Hydrophile-Lipophile Balance) value of 13 or more.

[0012] The polyoxyalkylene surfactant may be a compound represented by the following formula 2:

[0013] [ka]

[0014] In the above Chemical Formula 2, the R5 may be an alkyl group having 10 to 30 carbon atoms.

[0015] The R6 and R7 may each independently be a methyl group or an ethyl group.

[0016] The m and n may each independently be an integer of 10 to 30.

[0017] The ratio of the content (by weight) of the skew inhibitor to the content (by weight) of the polyoxyalkylene surfactant may be 0.3 to 1.2.

[0018] The weight average molecular weight of the polyoxyalkylene surfactant may be 500 g / mol to 4,000 g / mol.

[0019] The abrasive particles may have a positive surface charge.

[0020] The polishing composition for semiconductor processing may further include an anionic polymer dispersant.

[0021] The anionic polymer dispersant may include one or more compounds selected from the group consisting of polyacrylic acid, polymethacrylic acid, polymaleic acid, and derivatives thereof.

[0022] The polishing composition for semiconductor processing may have a pH of 5.5 to 12.

[0023] The polishing composition for semiconductor processing may have a zeta potential of −80 mV to −20 mV.

[0024] The polyoxyalkylene surfactant may be an agent for suppressing dishing of silicon oxide films.

[0025] The skew suppressing agent may be a skew suppressing agent for a silicon nitride film.

[0026] A method for manufacturing a substrate according to another embodiment of the present specification includes a step of polishing a substrate by applying the polishing composition for semiconductor processing as a slurry. [Effects of the Invention]

[0027] The polishing composition for semiconductor processing according to the embodiment can provide a smoother polished surface while maintaining a polishing rate above a certain level when polishing the surface of a substrate having two or more films. BEST MODE FOR CARRYING OUT THE INVENTION

[0028] Although the present invention will be described in detail below so that those skilled in the art can easily implement the present invention, it should be understood that the present invention may be embodied in many different forms and is not limited to the embodiments set forth herein.

[0029] As used herein, terms of degree such as "about," "substantially," etc., when given the tolerances of manufacturing and materials inherent in the referred meaning, are used in the sense of a numerical value or close to that numerical value, and are used to prevent unscrupulous infringers from unfairly exploiting disclosures in which precise or absolute numerical values ​​are mentioned to aid in the understanding of embodiments.

[0030] Throughout this specification, the term "combinations thereof" contained in a Markush form phrase means a mixture or combination of one or more selected from the group of elements set forth in the Markush form phrase, and means including one or more selected from the group of elements.

[0031] Throughout this specification, the phrase "A and / or B" means "A, B, or A and B."

[0032] Throughout this specification, terms such as "first", "second" or "A", "B" are used to distinguish identical terms from one another unless otherwise specified.

[0033] In this specification, the term "B is located on A" means that B can be located on A or B can be located on A with another layer located therebetween, and is not to be interpreted as being limited to B being located in contact with the surface of A.

[0034] In this specification, unless otherwise specified, the singular expression is to be construed as including the singular or plural as the context requires.

[0035] The term "-based compound" as used herein is intended to include compounds of the formula (I) and derivatives thereof. For example, a polyoxyalkylene-based compound refers to a compound containing polyoxyalkylene and its derivatives.

[0036] As semiconductors become more highly integrated, the density of patterns to be formed on wafers is increasing. When a substrate with a pattern formed on it is polished using the CMP process, defects such as over-polishing of the center of a wide pattern (dishing) or corrosion of the insulating film (skew) can occur. The frequency of such defects tends to increase as the pattern density increases.

[0037] The inventors of the embodiment experimentally confirmed that by using a polyoxyalkylene surfactant and a skew suppressant, etc., it is possible to provide a polishing composition that can smoothly polish the surface of a substrate on which two or more films, particularly a silicon oxide film and a silicon nitride film, are simultaneously exposed at a polishing rate above a certain level, and thus completed the embodiment.

[0038] The specific examples will be described below.

[0039] A polishing composition for semiconductor processing according to one embodiment of the present specification includes abrasive particles, a polyoxyalkylene surfactant, and a skew suppressant.

[0040] Polyoxyalkylene surfactants In an embodiment, the polishing composition may include a polyoxyalkylene surfactant, which is a surfactant derived from a polyoxyalkylene compound.

[0041] The polyoxyalkylene surfactant may be a dishing inhibitor for silicon oxide films. When polishing a substrate surface with an exposed silicon oxide film, the surfactant may be adsorbed to the surface of the silicon oxide film with an appropriate strength. The adsorbed surfactant may help to effectively suppress the dishing phenomenon of the silicon oxide film while maintaining the polishing rate of the polishing composition at a certain level or higher.

[0042] The polyoxyalkylene surfactant may be a nonionic surfactant, and the HLB (Hydrophile-Lipophile Balance) value of the polyoxyalkylene surfactant may be 13 or more.

[0043] In the present embodiment, a polyoxyalkylene surfactant having an HLB value controlled within a predetermined range can be stably dispersed in the polishing composition and easily adsorbed to the silicon oxide film, which exhibits hydrophilicity, thereby stably preventing over-polishing of the silicon oxide film.

[0044] The HLB value of the polyoxyalkylene surfactant is calculated by the following formula 1.

[0045] [Formula 1] JPEG0007825210000003.jpg1028

[0046] In the formula 1, M h is the molecular mass of the hydrophilic portion in the polyoxyalkylene surfactant, and M is the molecular weight of the entire polyoxyalkylene surfactant.

[0047] The polyoxyalkylene surfactant may have an HLB value of 13 or more. The HLB value may be 14 or more. The HLB value may be 15 or more. The HLB value may be less than 20. In such cases, the surfactant can be easily adsorbed to the silicon oxide film while being stably dispersed in the polishing composition.

[0048] The polyoxyalkylene surfactant may be a compound of the following formula 2:

[0049] [ka]

[0050] In the above Chemical Formula 2, R5 is an alkyl group having 10 to 30 carbon atoms, R6 and R7 are each independently a methyl group or an ethyl group, and m and n are each independently an integer of 10 to 30.

[0051] In the polyoxyalkylene surfactant having the composition of Chemical Formula 2, the portion containing the oxyalkylene repeating unit (-RO- repeating unit and -RO- repeating unit in Chemical Formula 2) can form hydrogen bonds with the silicon oxide film, thereby helping to form a stable passivation film on the oxide film. In addition, the portion containing the alkyl group (R functional group in Chemical Formula 2) in the surfactant can form steric hindrance near the silicon oxide film, effectively preventing the abrasive particles from excessively polishing the silicon oxide film.

[0052] In Formula 2, R5 may be an alkyl group having 10 to 30 carbon atoms. The number of carbon atoms may be 12 or more. The number of carbon atoms may be 25 or less. In this case, the polishing composition may be useful for polishing the surface of the substrate on which the silicon oxide film is exposed more smoothly, and an excessive increase in the degree of association of abrasive particles due to the use of a surfactant may be reliably prevented.

[0053] In the above Chemical Formula 2, m and n are each independently an integer of 10 to 30. The above m and n may each independently be an integer of 12 or greater. The above m and n may each independently be an integer of 25 or less.

[0054] The sum of m and n may be an integer of 20 or greater. The sum of m and n may be an integer of 24 or greater. The sum of m and n may be an integer of 60 or less. The sum of m and n may be an integer of 50 or less. The sum of m and n may be an integer of 40 or less.

[0055] The polyoxyalkylene surfactant having these characteristics can contribute to improving the smoothness of the substrate surface by being adsorbed to the surface of the silicon oxide film with a controlled strength, and can also prevent excessive deterioration of the dispersibility of the polishing composition due to the interaction between the surfactant and the abrasive particles.

[0056] The weight-average molecular weight of the polyoxyalkylene surfactant may be 500 g / mol to 4,000 g / mol. The weight-average molecular weight may be 1,000 g / mol or more. The weight-average molecular weight may be 3,000 g / mol or less. The weight-average molecular weight may be 2,500 g / mol or less. In such cases, the addition of the surfactant can stably control the dispersibility of abrasive particles in the polishing composition, and can effectively reduce the frequency of defects caused by over-polishing of the silicon oxide film when polishing a substrate surface with an exposed silicon oxide film.

[0057] The weight average molecular weight of the polyoxyalkylene surfactant can be measured by gel permeation chromatography (GPC).

[0058] Skew suppressant The polishing composition for semiconductor processing according to the embodiment may include a skew suppressor represented by the following Formula 1:

[0059] [ka]

[0060] In the above formula 1, R1 is H, a methyl group, or an ethyl group, and R2, R3, and R4 are each independently a methyl group or an ethyl group.

[0061] The skew suppressor of Formula 1 is a skew suppressor for a silicon nitride film. When polishing a substrate surface including a silicon nitride film, the skew suppressor is adsorbed onto the surface of the nitride film, thereby effectively suppressing excessive erosion of the nitride film that may occur during the polishing process.

[0062] The polishing composition of the present embodiment may contain both the polyoxyalkylene surfactant and the skew suppressor represented by Chemical Formula 1. The polishing selectivity of a silicon oxide layer relative to a silicon nitride layer can be improved, and a substrate surface on which both a silicon oxide layer and a silicon nitride layer are exposed can be polished smoothly. Furthermore, even if the compound is adsorbed onto the surface to be polished, the polishing composition can still exhibit a certain level of polishing rate.

[0063] In the embodiment, by adjusting the content ratio of the polyoxyalkylene surfactant and the skew suppressant, excessive deterioration of the polishing rate and dispersibility of the polishing composition can be prevented, while the frequency of defects on the polished surface can be reduced and the polishing selectivity of the silicon oxide film relative to the silicon nitride film can be improved.

[0064] In the polishing composition for semiconductor processing, the ratio of the content (by weight) of the skew suppressant to the content (by weight) of the polyoxyalkylene surfactant may be 0.3 to 1.2. The ratio may be 0.4 or more. The ratio may be 0.45 or more. The ratio may be 0.5 or more. The ratio may be 0.6 or more. The ratio may be 0.7 or more. The ratio may be 1.1 or less. The ratio may be 1.0 or less. In such cases, the polishing composition exhibits stable dispersibility, polishing rate, and polishing selectivity, and can efficiently reduce the frequency of defects on the polished surface.

[0065] Dispersants Embodiments may further include an anionic polymer dispersant. The dispersant may be stretched without agglomeration in a pH-controlled polishing composition. When such a dispersant is adsorbed to the surface of abrasive particles, particularly those with a positive surface charge, by electrostatic attraction, it forms significant steric hindrance around the abrasive particles, providing excellent dispersibility to the polishing composition. This characteristic may contribute to reducing the frequency of scratches on the polished surface due to agglomeration of abrasive particles.

[0066] The anionic polymer dispersant may comprise one or more compounds selected from the group consisting of polyacrylic acid, polymethacrylic acid, polymaleic acid, and derivatives thereof. The dispersant may comprise polyacrylic acid and derivatives thereof. The dispersant may comprise polyacrylic acid. The dispersant may be polyacrylic acid.

[0067] The weight-average molecular weight of the anionic polymer dispersant may be 1,000 g / mol to 50,000 g / mol. The weight-average molecular weight may be 2,000 g / mol or more. The weight-average molecular weight may be 3,000 g / mol or more. The weight-average molecular weight may be 5,000 g / mol or more. The weight-average molecular weight may be 10,000 g / mol or more. The weight-average molecular weight may be 40,000 g / mol or less. In this case, by adjusting the amount of dispersant adsorbed on the surface of the abrasive particles, excessive reduction in reactive sites of the abrasive particles can be suppressed, thereby maintaining the polishing properties of the polishing composition at a certain level or above. At the same time, the dispersibility of the abrasive particles can be effectively improved.

[0068] The weight average molecular weight of the dispersant can be measured by gel permeation chromatography.

[0069] The polishing composition for semiconductor processing may contain 50 to 200% by weight of anionic polymer dispersant per 100% by weight of abrasive particles. The polishing composition for semiconductor processing may contain 60% or more by weight of anionic polymer dispersant per 100% by weight of abrasive particles. The polishing composition for semiconductor processing may contain 70% or more by weight of anionic polymer dispersant per 100% by weight of abrasive particles. The polishing composition for semiconductor processing may contain 80% or more by weight of anionic polymer dispersant per 100% by weight of abrasive particles. The polishing composition for semiconductor processing may contain 90% or more by weight of anionic polymer dispersant per 100% by weight of abrasive particles. The polishing composition for semiconductor processing may contain 150% or less by weight of anionic polymer dispersant per 100% by weight of abrasive particles.

[0070] The polishing composition for semiconductor processing may contain 0.15 wt% or more of anionic polymer dispersant. The polishing composition for semiconductor processing may contain 0.2 wt% or more of anionic polymer dispersant. The polishing composition for semiconductor processing may contain 0.25 wt% or more of anionic polymer dispersant. The polishing composition for semiconductor processing may contain 0.5 wt% or less of anionic polymer dispersant.

[0071] In such a case, it may be useful to stably maintain the dispersibility of the abrasive particles.

[0072] The present embodiment may further include a zwitterion dispersant having a molecular weight of 50 g / mol to 300 g / mol. The zwitterion dispersant with an adjusted molecular weight may be adsorbed to portions of the surface of the abrasive particles where the anionic polymer dispersant has not been adsorbed, thereby further improving the dispersibility of the abrasive particles.

[0073] The zwitterion dispersant may include any one selected from the group consisting of picolinic acid, an amino acid, and a combination thereof. The amino acid may be, for example, at least one of glutamate, aspartate, glutamine, tyrosine, tryptophan, serine, threonine, glycine, alanine, methionine, cysteine, phenylalanine, leucine, valine, and isoleucine. The zwitterion dispersant may include picolinic acid. The zwitterion dispersant may be picolinic acid.

[0074] The polishing composition for semiconductor processing may contain 0.2 wt% to 15 wt% of a zwitterion dispersant relative to 100 wt% of abrasive particles. The polishing composition for semiconductor processing may contain 0.5 wt% or more of a zwitterion dispersant relative to 100 wt% of abrasive particles. The polishing composition for semiconductor processing may contain 0.8 wt% or more of a zwitterion dispersant relative to 100 wt% of abrasive particles. The polishing composition for semiconductor processing may contain 10 wt% or less of a zwitterion dispersant relative to 100 wt% of abrasive particles. The polishing composition for semiconductor processing may contain 8 wt% or less of a zwitterion dispersant relative to 100 wt% of abrasive particles. The polishing composition for semiconductor processing may contain 5 wt% or less of a zwitterion dispersant relative to 100 wt% of abrasive particles.

[0075] The polishing composition for semiconductor processing may contain 0.01 wt % to 0.5 wt % of a zwitterion dispersant. The polishing composition for semiconductor processing may contain 0.02 wt % or more of a zwitterion dispersant. The polishing composition for semiconductor processing may contain 0.03 wt % or more of a zwitterion dispersant. The polishing composition for semiconductor processing may contain 0.05 wt % or more of a zwitterion dispersant. The polishing composition for semiconductor processing may contain 0.4 wt % or less of a zwitterion dispersant. The polishing composition for semiconductor processing may contain 0.3 wt % or less of a zwitterion dispersant.

[0076] In such a case, it is possible to contribute to a more effective reduction in the frequency with which scratches occur on the polished surface.

[0077] The polishing composition for semiconductor processing may further include a non-ionic polymer dispersant. The non-ionic polymer dispersant can increase dispersibility by adsorbing to the abrasive particles, while the non-adsorbed non-ionic polymer dispersant can further enhance dispersion stability through a steric hindrance effect, etc. In addition, the non-ionic nature of the dispersant allows the polishing composition for semiconductor processing to have more stable dispersion stability even in an acidic environment, as described below. In addition, the occurrence of polishing defects on the substrate during the polishing process can be reduced.

[0078] The nonionic polymer may be at least one selected from the group consisting of polyethylene glycol, polypropylene glycol, polyvinylpyrrolidone, polyethylene oxide, polypropylene oxide, polyalkyl oxide, polyoxyethylene oxide, polyethylene oxide-propylene oxide copolymer, cellulose, methyl cellulose, methylhydroxyethyl cellulose, methylhydroxypropyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, carboxymethylhydroxyethyl cellulose, sulfoethyl cellulose, and carboxymethylsulfoethyl cellulose.

[0079] The nonionic polymer may have a weight-average molecular weight of 1,000 g / mol or more and less than 25,000 g / mol, which is advantageous in terms of polishing properties and exhibits superior solubility and dispersion stability.

[0080] The nonionic polymer may be contained in an amount of 0.01 to 5 wt % or 0.1 to 2 wt % based on the total weight of the polishing composition for semiconductor processing, which can suppress the occurrence of defects on the polished substrate surface and can control the degree of contamination, such as particle re-adhesion, on the polished substrate surface to a certain level or less.

[0081] Abrasive particles and other compounds The surface charge of the abrasive particles may be positive, in which case the anionic polymer dispersant can be easily adsorbed onto the surface of the abrasive particles due to electrostatic attraction.

[0082] The abrasive particles may include any one selected from the group consisting of ceria, silica, zirconia, alumina, zeolite, and combinations thereof. The abrasive particles may include surface-modified particles.

[0083] The abrasive particles may include ceria. The abrasive particles may be ceria. Ceria can react with the thin film to be polished during the polishing process to exhibit high polishing properties. In addition, since the surface of ceria exhibits a positive charge, it may be easy to improve the dispersibility of the abrasive particles using an anionic polymer dispersant.

[0084] The abrasive particles may include colloidal ceria particles. The abrasive particles may be colloidal ceria. Colloidal ceria may have higher density and crystallinity than ceria formed by a solid-phase process. These characteristics can impart improved polishing properties to the polishing composition. Furthermore, colloidal ceria has a relatively uniform particle shape and particle size distribution, which can effectively reduce the frequency of defects on the polished surface.

[0085] The abrasive particles may have an average secondary particle diameter of 100 nm or more. The average diameter may be 110 nm or more. The average diameter may be 120 nm or more. The average diameter may be 130 nm or more. The average diameter may be 170 nm or less. The average diameter may be 160 nm or less. The average diameter may be 150 nm or less. A polishing composition containing such particles can reduce the frequency of defects such as scratches on the polished surface and exhibit an excellent polishing rate for the substrate surface.

[0086] The average diameter of the primary particles of the abrasive particles may be 30 nm or more. The average diameter may be 40 nm or more. The average diameter may be 50 nm or more. The average diameter may be 200 nm or less. The average diameter may be 150 nm or less. The average diameter may be 120 nm or less. The average diameter may be 90 nm or less. In such cases, the frequency at which the abrasive particles adsorb onto the substrate can be stably controlled, and the polishing composition can exhibit an excellent polishing rate for the substrate surface.

[0087] The abrasive particles may contain 50% or more by weight of ceria particles. The abrasive particles may contain 70% or more by weight of ceria particles. The abrasive particles may contain 90% or more by weight of ceria particles. The abrasive particles may contain 100% or less by weight of ceria particles. The abrasive particles may be ceria particles.

[0088] The abrasive particles may contain 50% or more by weight of colloidal ceria particles. The abrasive particles may contain 70% or more by weight of colloidal ceria particles. The abrasive particles may contain 90% or more by weight of colloidal ceria particles. The abrasive particles may contain 100% or less by weight of colloidal ceria particles. The abrasive particles may be colloidal ceria particles.

[0089] The polishing composition for semiconductor processing may contain 0.1 wt% or more abrasive particles. The polishing composition for semiconductor processing may contain 0.15 wt% or more abrasive particles. The polishing composition for semiconductor processing may contain 0.2 wt% or more abrasive particles. The polishing composition for semiconductor processing may contain 5 wt% or less abrasive particles. The polishing composition for semiconductor processing may contain 3 wt% or less abrasive particles. The polishing composition for semiconductor processing may contain 1.5 wt% or less abrasive particles. In such cases, efficient polishing is possible, especially for substrate surfaces where both oxide and nitride films are exposed.

[0090] The polishing composition for semiconductor processing may further include a chelator. The chelator adsorbs metals or metal ions to facilitate their removal. Specifically, metals that may be generated during the polishing process may re-adhere to the polished surface or remain in subsequent processes, potentially causing defects. In particular, metals such as tungsten are relatively easily dissolved in certain environments, but they also tend to re-adhere to surfaces. To prevent this, a chelator can be used as a sequestering agent.

[0091] For example, the chelator may be at least one selected from the group consisting of butyric acid, citric acid, tartaric acid, succinic acid, oxalic acid, acetic acid, adipic acid, capric acid, caproic acid, caprylic acid, carboxylic acid, glutaric acid, glutamic acid, glycolic acid, thioglycolic acid, formic acid, mandelic acid, fumaric acid, lactic acid, lauric acid, malic acid, malonic acid, myristic acid, palmitic acid, phthalic acid, isophthalic acid, terephthalic acid, citraconic acid, propionic acid, pyruvic acid, stearic acid, valeric acid, benzoic acid, phenylacetic acid, naphthoic acid, aspartic acid, amino acids, and ethylenediaminetetraacetic acid. The amino acids may be glycine, α-alanine, β-alanine, L-aspartic acid, N-methylglycine (methylglycine), or a combination thereof.

[0092] The chelator may contain two or more carboxyl or alcohol groups in the molecule. Two or more types of chelators containing two or more carboxyl or alcohol groups in the molecule can be used. Specifically, the chelator may include any one selected from the group consisting of EDTA (ethylenediaminetetraacetic acid), glycine, carboxylic acids, and combinations thereof. The carboxylic acids refer to compounds containing at least one or two or more carboxyl groups in the molecule.

[0093] The chelator may be contained in an amount of 0.003 to 0.5 wt % or 0.005 to 0.3 wt % based on the total weight of the polishing composition for semiconductor processing, which can reduce the frequency of defects caused by particles originating from the metal thin film.

[0094] The polishing composition for semiconductor processing may further include an oxidizing agent, which oxidizes the metal thin film to create an environment that facilitates planarization and improves the polishing rate and etching rate.

[0095] The oxidizing agent may be at least one selected from the group consisting of hydrogen peroxide, urea hydrogen peroxide, urea, percarbonate, periodic acid, periodate, perchloric acid, perchlorates, perbromic acid, perbromates, perboric acid, perborates, permanganic acid, permanganates, persulfates, bromates, chlorates, chlorites, chromates, iodates, iodic acid, ammonium persulfate, benzoyl peroxide, calcium peroxide, barium peroxide, sodium peroxide, and urea peroxide.

[0096] The oxidizing agent may be contained in an amount of 0.01 to 5 wt % based on the total weight of the polishing composition for semiconductor processing, and in this case, the degree of oxidation of the metal thin film is controlled, thereby adjusting the polishing rate within a stable range.

[0097] To adjust the pH of the polishing composition for semiconductor processing, an acid component may be added to the composition in addition to the solvent. The acid component may be applied together with a pH adjuster.

[0098] The acid component may be, for example, at least one selected from the group consisting of hydrochloric acid, phosphoric acid, sulfuric acid, hydrofluoric acid, bromic acid, iodic acid, formic acid, malonic acid, oxalic acid, acetic acid, adipic acid, citric acid, propionic acid, fumaric acid, lactic acid, salicylic acid, pimelic acid, benzoic acid, succinic acid, phthalic acid, butyric acid, glutaric acid, glutamic acid, glycolic acid, aspartic acid, tartaric acid, and salts thereof.

[0099] The pH adjuster may be any one selected from the group consisting of ammonia, aminomethylpropanol, tetramethylammonium hydroxide, potassium hydroxide, sodium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, sodium bicarbonate, sodium carbonate, imidazole, and combinations thereof.

[0100] The acid component and pH adjuster can be applied in an amount appropriate for the intended pH.

[0101] The polishing composition for semiconductor processing contains a solvent as the remaining component, excluding the components described above and the additional components described below. The solvent may be water, and preferably ultrapure water.

[0102] Physical properties of polishing composition In some embodiments, adjusting the pH of the polishing composition can contribute to inhibiting agglomeration of abrasive particles. Specifically, when the pH of the polishing composition is adjusted, the anionic polymer dispersant contained in the composition maintains a stretched state without condensing even when adsorbed on the surface of the abrasive particles, thereby forming significant steric hindrance around the abrasive particles. This can effectively prevent agglomeration between the abrasive particles.

[0103] The polishing composition for semiconductor processing may have a pH of 5.5 to 12. The pH may be 6 or higher. The pH may be 7 or higher. The pH may be 11 or lower. The pH may be 10 or lower. In such cases, the degree of concentration of the dispersant in the polishing composition is adjusted, which can contribute to improving the dispersibility of the polishing composition.

[0104] The zeta potential of the polishing composition for semiconductor processing may be -80mV to -20mV. The zeta potential may be -70mV or more. The zeta potential may be -60mV or more. The zeta potential may be -55mV or more. The zeta potential may be -25mV or less. The zeta potential may be -35mV or less.

[0105] In such a case, the dispersibility of the polishing composition can be improved, and the frequency of scratches occurring on the surface to be polished can be effectively reduced.

[0106] The pH and zeta potential of the polishing composition are measured by a measurement method commonly used in the field of polishing compositions for semiconductor processing.

[0107] The polishing rate of the polishing composition for semiconductor processing against a silicon oxide film may be 1000 Å / min or more. The polishing rate of the polishing composition for semiconductor processing against a silicon oxide film may be 1100 Å / min or more. The polishing rate of the polishing composition for semiconductor processing against a silicon oxide film may be 1200 Å / min or more. The polishing rate of the polishing composition for semiconductor processing against a silicon oxide film may be 3000 Å / min or less.

[0108] The polishing rate of the polishing composition for semiconductor processing to a silicon nitride film may be 300 Å / min or less. The polishing rate of the polishing composition for semiconductor processing to a silicon nitride film may be 250 Å / min or less. The polishing rate of the polishing composition for semiconductor processing to a silicon nitride film may be 200 Å / min or less. The polishing rate of the polishing composition for semiconductor processing to a silicon nitride film may be 180 Å / min or less. The polishing rate of the polishing composition for semiconductor processing to a silicon nitride film may be 150 Å / min or less. The polishing rate of the polishing composition for semiconductor processing to a silicon nitride film may be 30 Å / min or more.

[0109] The polishing composition for semiconductor processing may have a polishing selectivity ratio of silicon oxide film to silicon nitride film of 10 or more. The polishing selectivity ratio may be 12 or more. The polishing selectivity ratio may be 15 or more. The polishing selectivity ratio may be 20 or more. The polishing selectivity ratio may be 35 or less. In such cases, when etching a surface where a silicon oxide film and a silicon nitride film are simultaneously exposed, the generation of excessive steps on the surface to be polished can be effectively suppressed.

[0110] When measuring the polishing rate of the polishing composition for semiconductor processing, the substrate to be polished is a patterned wafer with a pitch of 1000 μm and a density of 50% silicon oxide and silicon nitride films, the carrier / platen speed is 93 / 87 RPM, the slurry flow rate is 100 ml / min, and the polishing pressure is 4.0 psi. When measuring the dishing value, the polishing pad can be an HD-500C pad manufactured by SK Empulse.

[0111] The polishing composition for semiconductor processing may include a silicon nitride film and a silicon oxide film, and may have a dishing value of the silicon oxide film of 600 Å or less when polishing a substrate having a pattern density of 50% for 200 seconds.

[0112] When measuring dishing value, the substrate to be polished is a patterned wafer with a pitch of 1000 μm and a density of 50% silicon oxide and silicon nitride films, the carrier / platen speed is 93 / 87 RPM, the slurry flow rate is 100 ml / min, and the polishing pressure is 4.0 psi. When measuring dishing value, the polishing pad used can be an HD-500C pad from SK Empulse.

[0113] Polishing the substrate for 200 seconds means polishing a substrate having a smooth surface for 200 seconds, or polishing a substrate having a step on the top surface and then polishing the substrate for an additional 200 seconds from the point where the substrate begins to have a smooth surface.

[0114] The polishing composition for semiconductor processing may have a silicon nitride film and a silicon oxide film, and when a substrate having a pattern density of 50% is polished for 200 seconds, the dishing value of the silicon oxide film may be 600 Å or less. The dishing value may be 500 Å or less. The dishing value may be 450 Å or less. The dishing value may be 400 Å or less. The dishing value may be 380 Å or less. The dishing value may be 100 Å or more. A composition having these characteristics can provide a smoother polished surface.

[0115] The polishing composition for semiconductor processing may include a silicon nitride film and a silicon oxide film, and when a substrate having a pattern density of 50% is polished for 200 seconds, the silicon nitride film may have a skew value of 500 Å or less.

[0116] The skew value of the silicon nitride film means the depth to which the silicon nitride film is polished when the substrate is polished.

[0117] When measuring the skew of the silicon nitride film, the polishing conditions are the same as when measuring the dishing value of the silicon oxide film.

[0118] The polishing composition for semiconductor processing may have a skew value of 500 Å or less when polishing a substrate containing a silicon nitride film and a silicon oxide film and having a pattern density of 50% for 200 seconds. The skew value may be 400 Å or less. The skew value may be 350 Å or less. The skew value may be 300 Å or less. The skew value may be 280 Å or less. The skew value may be 250 Å or less. The skew value may be 50 Å or more. In such cases, the degree of step formation on the polished surface due to over-polishing can be effectively suppressed.

[0119] Substrate manufacturing method A method for manufacturing a substrate according to yet another embodiment of the present specification includes a step of polishing a substrate by applying the polishing composition for semiconductor processing described above as a slurry.

[0120] The substrate may include at least one of an insulating film, a metal wiring, and a barrier layer on an upper surface. The metal wiring may include copper or tungsten. When the metal wiring includes copper, the barrier layer may include tantalum and its nitride. When the metal wiring includes tungsten, the barrier layer may include titanium and its nitride. The insulating film may include a silicon nitride film or a silicon oxide film.

[0121] Specifically, the process of polishing a substrate involves contacting the substrate to be polished with a polishing composition for semiconductor processing supplied from a spray nozzle onto a polishing pad, while the polishing head that fixes the substrate rotates and the platen on which the polishing pad is attached also rotates.

[0122] The process of polishing a substrate can further include, if necessary, conditioning the surface of the polishing pad before polishing.

[0123] The polishing composition for semiconductor processing can polish a wafer in contact with the polishing pad while penetrating toward the substrate.

[0124] In the process of polishing the substrate, a pressure of 6.89 kPa to 48.26 kPa may be applied, and the pressure may be 13.79 kPa to 34.47 kPa.

[0125] The process of polishing the substrate may be carried out for 50 seconds to 10 minutes, although this can be changed depending on the desired degree of polishing.

[0126] The explanation of the polishing composition for semiconductor processing is omitted here since it is the same as that described above.

[0127] The method for manufacturing a substrate may further include a cleaning process for cleaning the substrate after polishing.

[0128] The cleaning process may be performed by cleaning the polished substrate with purified water and an inert gas.

[0129] Specific examples will be described in more detail below.

[0130] Manufacturing example: Manufacturing of polishing compound for semiconductor process Example 1: 0.3 wt% colloidal ceria as abrasive particles, 2.7 wt% KONION SM-30 from Green Chemical Co. as a polyoxyalkylene surfactant, 1.2 wt% tetramethylethylenediamine as a skew suppressant, and 0.35 wt% polyacrylic acid as an anionic polymer dispersant were added to ultrapure water as a solvent to prepare a polishing composition with a total weight of 100%.

[0131] Example 2: A polishing composition of 100 wt % in total was prepared under the same conditions as in Example 1, except that 2.0 wt % of the polyoxyalkylene surfactant and 1.6 wt % of the skew inhibitor were used.

[0132] Example 3: A polishing composition of 100 wt % in total was prepared under the same conditions as in Example 1, except that the skew inhibitor was added in an amount of 1.6 wt %.

[0133] Example 4: A polishing composition of 100 wt % in total was prepared under the same conditions as in Example 1, except that 3.3 wt % of the polyoxyalkylene surfactant and 1.6 wt % of the skew suppressant were used.

[0134] Example 5: A polishing composition of 100 wt % in total was prepared under the same conditions as in Example 1, except that the skew inhibitor was added in an amount of 2.0 wt %.

[0135] Comparative Example 1: A polishing composition of 100 wt % in total was prepared under the same conditions as in Example 1, except that 0.6 wt % of the polyoxyalkylene surfactant and 0.8 wt % of the skew inhibitor were used.

[0136] The composition, pH, zeta potential, and diameter of the abrasive particles (secondary particles) of the polishing compositions of the examples and comparative examples are shown in Table 1 below.

[0137] Evaluation example: Measurement of dishing value of silicon oxide film and skew value of silicon nitride film Using the polishing compositions for semiconductor processing in Examples and Comparative Examples, substrates having a silicon nitride layer and a silicon oxide layer, a smooth surface, and a pattern density of 50% were polished for 200 seconds using an SK Empulse HD-500C polishing pad, a carrier / platen speed of 93 / 87 RPM, a slurry flow rate of 100 mL / min, and a polishing pressure of 4 psi.

[0138] After polishing, the step height of the polished silicon oxide film was measured, and the measured value was taken as the dishing value of the silicon oxide film.

[0139] The polished depth of the polished silicon nitride film was measured, and the measured value was taken as the skew value of the silicon nitride film.

[0140] The measurement results for each of the examples and comparative examples are shown in Table 2 below.

[0141] Evaluation example: Measurement of polishing rate and frequency of scratches on the polished surface Each of the polishing compositions for semiconductor processing in Examples and Comparative Examples was used to polish a silicon nitride wafer and a silicon oxide wafer for 60 seconds, respectively, at a polishing pressure of 4.0 psi.

[0142] After polishing, the polished depths of the silicon oxide film and the silicon nitride film in the substrate were measured, and the polishing rates were calculated from the measured values.The polishing selectivity of the silicon oxide film to the silicon nitride film was calculated from the polishing rates of the silicon oxide film and the silicon nitride film.

[0143] In addition, the number of scratches formed in the substrate after polishing was measured using a wafer defect detector, AIT-XP+ model manufactured by KLA Tencor.

[0144] The measurement results for each of the examples and comparative examples are shown in Table 2 below.

[0145] [Table 1] *RS / O : Ratio of the content (wt%) of the skew inhibitor to the content (wt%) of the polyoxyalkylene surfactant

[0146] [Table 2]

[0147] In Table 2, the dishing values ​​of the silicon oxide films in Examples 1 to 5 were measured to be 520 Å or less, whereas in Comparative Example 1 it was measured to be over 1000 Å.

[0148] The skew values ​​of the silicon nitride films in Examples 1 to 5 were measured to be 115 Å or less, whereas in Comparative Example 1 it was measured to be over 135 Å.

[0149] With regard to the polishing selectivity, Examples 1 to 5 exhibited values ​​of 17 or more, whereas Comparative Example 1 exhibited a value of less than 15.5.

[0150] This means that when the ratio of the content of the skew inhibitor to the content of the polyoxyalkylene surfactant is adjusted within a predetermined range in an embodiment, it is possible to reduce the dishing value of a silicon oxide film and the skew value of a silicon nitride film below a certain level and exhibit excellent polishing selectivity.

[0151] The frequency of scratches on the polished surface in the examples and comparative examples was less than 700. This means that the addition of the anionic polymer dispersant effectively improved the dispersibility of the abrasive particles.

[0152] Although the preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts of the embodiments defined in the appended claims also fall within the scope of the present invention.

Claims

1. The polishing agent includes abrasive particles, a polyoxyalkylene surfactant, and a skew inhibitor represented by the following formula 1: the ratio of the content (by weight) of the skew suppressant to the content (by weight) of the polyoxyalkylene surfactant is 0.3 to 1.2; The polishing composition for semiconductor processing, wherein the polyoxyalkylene surfactant has an HLB (Hydrophile-Lipophile Balance) value of 13 or more. 【Chemistry 1】 (In the above Chemical Formula 1, R １ is H, a methyl group or an ethyl group, R ２ , R ３ and R ４ are each independently a methyl group or an ethyl group.

2. 2. The polishing composition for semiconductor processing according to claim 1, wherein the polyoxyalkylene surfactant is a compound represented by the following formula 2: 【Chemistry 2】 (In the above Chemical Formula 2, R ５ is an alkyl group having 10 to 30 carbon atoms, R ６ and R ７ are each independently a methyl group or an ethyl group, m and n are each independently an integer of 10 to 30.

3. 2. The polishing composition for semiconductor processing according to claim 1, wherein the weight average molecular weight of the polyoxyalkylene surfactant is 500 g / mol to 4,000 g / mol.

4. the abrasive particles have a positive surface charge; The polishing composition for semiconductor processing according to claim 1 , further comprising an anionic polymer dispersant.

5. 5. The polishing composition for semiconductor processing according to claim 4, wherein the anionic polymer dispersant comprises one or more compounds selected from the group consisting of polyacrylic acid, polymethacrylic acid, polymaleic acid, and derivatives thereof.

6. 2. The polishing composition for semiconductor processing according to claim 1, wherein the pH is 5.5 to 12.

7. 2. The polishing composition for semiconductor processing according to claim 1, wherein the zeta potential is −80 mV to −20 mV.

8. the polyoxyalkylene surfactant is a dishing inhibitor for silicon oxide films, 2. The polishing composition for semiconductor processing according to claim 1, wherein the skew suppressing agent is a skew suppressing agent for a silicon nitride film.

9. A method for manufacturing a substrate, comprising the step of polishing a substrate by applying the polishing composition for semiconductor processing according to claim 1 as a slurry.

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