Polishing composition for semiconductor process and method for manufacturing substrate using same

Abstract

A polishing composition for a semiconductor process according to an embodiment of the present specification includes polishing particles, iron ions, and an iron ion stabilizer. The iron ion stabilizer contains more than two carboxyl groups. The polishing composition for a semiconductor process has an electrical conductivity of 200 [mu] s / cm to 800 [mu] s / cm. The polishing composition having these characteristics can more smoothly polish the surface of a substrate including a tungsten pattern film having fine pitch.

Description

Technical Field

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

[0002] As semiconductor devices become more sophisticated and high-density, more sophisticated pattern forming technologies are being used. Accordingly, the surface structure of semiconductor devices has become more complex, and the step difference between interlayer films has become larger. When manufacturing semiconductor devices, a chemical mechanical polishing (CMP) process is used as a flattening technology for removing the step difference of a specific film formed on a substrate.

[0003] In the CMP process, slurry is supplied to the polishing pad, and the surface is polished while the substrate is pressed and rotated. Depending on the process step, the object to be flattened changes, and the physical properties of the slurry used at this time also vary.

[0004] Polishing after forming metal wiring needs to maintain a sufficient polishing rate and polishing speed while minimizing dishing, corrosion, etc.

[0005] Prior art literature

[0006] Patent Literature

[0007] (Patent Document 1) Korean Patent No. 10-1293790 Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] An object of the present embodiment is to provide a polishing composition for semiconductor processes that can smoothly polish the surface of a substrate including a fine-pitch tungsten pattern film.

[0010] Means for solving technical problems

[0011] A polishing composition for semiconductor processing according to an embodiment of the present disclosure includes polishing particles, iron ions, and an iron ion stabilizer.

[0012] The iron ion stabilizer contains two or more carboxyl groups.

[0013] The above-mentioned polishing composition for semiconductor process has an electrical conductivity of 200 μs / cm to 800 μs / cm.

[0014] The iron ion stabilizer may be any one selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, and combinations thereof.

[0015] In the semiconductor process polishing composition, the ratio of the content of the iron ion stabilizer to the content of the iron ions may be 3 to 50 by weight.

[0016] The semiconductor process polishing composition may include 1*10 -4 Weight% to 5*10 -3 % by weight of the above iron ions.

[0017] The above-mentioned polishing composition for semiconductor process may further contain a polyglyceryl compound.

[0018] The polyglyceryl compound may have a weight average molecular weight of about 300 to about 1,200 g / mol.

[0019] The polishing composition for semiconductor process may contain 0.001 wt % to 0.1 wt % of the polyglyceryl compound.

[0020] In the above-mentioned polishing composition for semiconductor process, the polishing selectivity ratio of the silicon oxide film to the tungsten film may be 1 to 5.

[0021] The pH of the semiconductor process polishing composition may be 1.5 to 4.5.

[0022] The number of particles having a diameter exceeding 1 μm per unit volume of the polishing composition for semiconductor processes measured by a large particle counter (LPC) may be 80 particles / ml or less.

[0023] A method for manufacturing a substrate according to another embodiment of the present specification includes a process of polishing a substrate by using the above-mentioned polishing composition for a semiconductor process as a slurry.

[0024] Effects of the Invention

[0025] The polishing composition for semiconductor processes of the present embodiment can smoothly polish the surface of a substrate including a fine-pitch tungsten pattern film. DETAILED DESCRIPTION

[0026] Hereinafter, the embodiments will be described in detail so that those skilled in the art can easily implement the embodiments. The embodiments can be implemented in many different ways and are not limited to the embodiments described herein.

[0027] The terms "about" or "substantially" and the like used in this specification are used to express a numerical value or a value close to a numerical value when there are inherent manufacturing and material tolerances in the meaning involved, and are intended to prevent the accurate or absolute numerical values ​​disclosed in this embodiment from being improperly used by any unscrupulous infringers for understanding.

[0028] Throughout this specification, the term "combination thereof" included in the description of the Markush form refers to a mixture or combination of one or more constituent elements selected from the group consisting of the constituent elements described in the Markush form, thereby meaning that the present invention includes one or more constituent elements selected from the group consisting of the above constituent elements.

[0029] Throughout the present specification, descriptions in the form of "A and / or B" mean "A, B, or A and B".

[0030] Throughout the present specification, unless otherwise specified, terms such as "first", "second" or "A", "B" etc. are used to distinguish the same terms from each other.

[0031] In the present specification, B being located on A means that B is located on A or, with another layer therebetween, B is located on A or may be located on A, and should not be limited to the meaning that B is located on the surface of A in a contacting manner.

[0032] Unless otherwise specified, expressions in the singular in the present specification are interpreted as including the singular or plural meaning as explained in the context.

[0033] The "polyglyceryl compound" includes a "polyglyceryl compound" and its derivatives. For example, a polyglyceryl compound refers to a polyglycerol compound and a derivative of a polyglycerol compound.

[0034] The process of polishing the substrate surface including the tungsten pattern film can be performed in two steps as follows, that is, a tungsten primary polishing process of polishing the tungsten body layer to expose the tungsten pattern film and the insulating layer and a tungsten secondary polishing process of reducing the step difference between the tungsten pattern film and the insulating layer can be performed.

[0035] As the film pitch of the tungsten pattern decreases, the frequency of defect problems in the tungsten secondary polishing process increases. Specifically, defects such as increased step difference of the contact pattern and misalignment with the upper contact pattern may occur more frequently.

[0036] The polishing composition according to the present embodiment can provide a smooth polished surface with reduced defects even when the surface of a substrate including a fine-pitch tungsten pattern film is polished.

[0037] Hereinafter, the present embodiment will be described in detail.

[0038] Composition of polishing composition

[0039] Iron ions and iron ion stabilizers

[0040] A polishing composition for a semiconductor process according to an embodiment includes polishing particles, iron ions, and an iron ion stabilizer.

[0041] The iron ions may be derived not only from common iron ion compounds but also from compounds including iron ion complexes, iron ion compounds and hydrates of iron ion complexes.

[0042] During the polishing process of the tungsten pattern film, the iron ions promote the oxidation of tungsten. In addition, the iron ions can help to make the polishing composition have a controlled Zeta potential. Thus, the iron ions can prevent the polishing composition from over-polishing the insulating film, specifically, the silicon oxide film. In addition, the polishing performance of the polishing composition for the tungsten film can be improved, and the situation of the step difference on the polished substrate due to the over-polishing of the silicon oxide film can be suppressed.

[0043] The iron ions may be ferrous ions or ferric ions.

[0044] Illustratively, the iron ions may be derived from ferric chloride, ferric nitrate, ferric sulfate, ferric perchlorate, ferric acetate, ferric citrate, Fe(III)-EDTA (Ethylenediaminetetraacetic Acid), etc., but are not limited thereto.

[0045] On the other hand, the iron ions in the polishing composition may have relatively high reactivity. Due to these characteristics, the iron ions may not participate in the reaction of the tungsten oxide film, but become a reactant of the side reaction. The iron ion stabilizer can help to make a larger amount of iron ions available for the tungsten film polishing process by stabilizing the iron ions in the polishing composition.

[0046] The iron ion stabilizer may contain two or more carboxyl groups, which can form coordination bonds with iron ions to adjust the reactivity of iron ions in the polishing composition.

[0047] The iron ion stabilizer can be any one selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid and combinations thereof. The iron ion stabilizer can be any one selected from the group consisting of oxalic acid, malonic acid, succinic acid and combinations thereof.

[0048] In this embodiment, the content ratio of iron ions and iron ion stabilizer can be adjusted within a preset range, thereby stabilizing a sufficient amount of iron ion compounds in the polishing composition, and effectively improving the polishing performance of the polishing composition for tungsten film.

[0049] In the polishing composition for semiconductor process, the ratio of the content of the iron ion stabilizer (by weight) to the content of the iron ion (by weight) may be 3 to 50. The above ratio may be 5 or more. The above ratio may be 10 or more. The above ratio may be 14 or more. The above ratio may be 40 or less. The above ratio may be 30 or less. In this case, the iron ion stabilizer can sufficiently control the reactivity of the iron ions in the polishing composition, and the pH of the polishing composition can be suppressed from being excessively lowered due to the iron ion stabilizer.

[0050] The semiconductor process polishing composition may contain 1*10 -4 Weight% to 5*10 -3 The polishing composition may contain 3*10 -4 The polishing composition may contain 5 to 10 -4 The polishing composition may contain 4*10 -3 The above polishing composition may contain 3*10 -3 In this case, the polishing performance of the polishing composition for the tungsten film and the silicon oxide film can be adjusted simultaneously. Thus, the surface of the substrate including the finely formed tungsten pattern film can be polished more smoothly.

[0051] The iron ion content in the polishing composition for semiconductor process can be measured by inductively coupled plasma optical emission spectroscopy (ICP-OES).

[0052] Polyglyceryl compounds

[0053] The polishing composition for semiconductor processing may further include a polyglyceryl compound. The polyglyceryl compound acts as a surfactant in the polishing composition, thereby helping to easily remove particles or polishing pad fragments remaining on the surface of the polished substrate. In addition, the above-mentioned compound can prevent the polishing particles of this embodiment from aggregating to form large particles during the polishing process, thereby helping to inhibit the polishing particles from scratching the polished surface.

[0054] The polyglyceryl compound may have a weight average molecular weight of 300 g / mol to 1,200 g / mol. The weight average molecular weight may be 400 g / mol or more. The weight average molecular weight may be 500 g / mol or more. The weight average molecular weight may be 1,100 g / mol or less. The weight average molecular weight may be 1,000 g / mol or less. In this case, foreign matter can be prevented from being adsorbed on the surface of the polished substrate, and the dispersibility of the polishing particles can be effectively improved.

[0055] The weight average molecular weight of the polyglyceryl compound can be measured by GPC (Gel Permeation Chromatography).

[0056] The polishing composition may contain 0.001 wt % to 0.1 wt % of a polyglyceryl compound. The polishing composition may contain 0.003 wt % or more of a polyglyceryl compound. The polishing composition may contain 0.005 wt % or more of a polyglyceryl compound. The polishing composition may contain 0.07 wt % or less of a polyglyceryl compound. The polishing composition may contain 0.05 wt % or less of a polyglyceryl compound. The polishing composition may contain 0.03 wt % or less of a polyglyceryl compound. In this case, organic particles remaining on the surface of the substrate can be easily removed. In addition, it can help reduce the number of defects occurring on the surface of the polished substrate to below a specified level.

[0057] Polishing particles

[0058] The polishing particles may include metal oxide particles and / or silicon oxide particles. The polishing particles may include silicon dioxide. The polishing particles may include colloidal silicon dioxide.

[0059] The polishing particles may include more than 70% by weight of colloidal silica. The polishing particles may include more than 80% by weight of colloidal silica. The polishing particles may include more than 90% by weight of colloidal silica. The polishing particles may be colloidal silica.

[0060] The surface of the polishing particle may have a positive charge. The polishing particle may be surface modified so that its surface has a positive charge. The polishing particle may be surface modified with a compound having an amino group. The polishing particle may be surface modified with an aminosilane.

[0061] For example, the aminosilane may be selected from 3-aminopropyltriethoxysilane, bis[(3-triethoxysilyl)propyl]amine, 3-aminopropyltrimethoxysilane, bis[(3-trimethoxysilyl)propyl]amine, 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, N-[3-(trimethoxysilyl)propyl]ethylenediamine, N-bis[3-(trimethoxysilyl)propyl]-1, Any one of the group consisting of 2-ethylenediamine, N-[3-(triethoxysilyl)propyl]ethylenediamine, diethylenetriaminopropyltrimethoxysilane, diethylenetriaminopropylmethyldimethoxysilane, diethylaminomethyltriethoxysilane, diethylaminopropyltrimethoxysilane, diethylaminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, N-[3-(trimethoxysilyl)propyl]butylamine and combinations thereof.

[0062] The polishing composition for semiconductor process may contain 15ppm (by weight) to 200ppm (by weight) of aminosilane. The polishing composition for semiconductor process may contain 20ppm (by weight) or more of aminosilane. The polishing composition for semiconductor process may contain 25ppm (by weight) or more of aminosilane. The polishing composition for semiconductor process may contain 30ppm (by weight) or more of aminosilane. The polishing composition for semiconductor process may contain 150ppm (by weight) or less of aminosilane. The polishing composition for semiconductor process may contain 100ppm (by weight) or less of aminosilane. The polishing composition for semiconductor process may contain 70ppm (by weight) or less of aminosilane. The polishing composition for semiconductor process may contain 50ppm (by weight) or less of aminosilane. In this case, the surface of the substrate to be polished can be polished more smoothly, and improved dispersibility can be presented. At the same time, it is possible to effectively prevent the above-mentioned residues from being adsorbed on the polished surface due to the generation of surface modifier residues.

[0063] The semiconductor process polishing composition may contain 1 wt % to 10 wt % of polishing particles. The semiconductor process polishing composition may contain more than 2 wt % of polishing particles. The semiconductor process polishing composition may contain less than 8 wt % of polishing particles. The semiconductor process polishing composition may contain less than 5 wt % of polishing particles. In this case, the polishing composition may have an excellent polishing rate to the polished surface and stably suppress the aggregation of the polishing particles.

[0064] The average particle size of the polishing particles may be 20 nm or more. The particle size may be 30 nm or more. The particle size may be 40 nm or more. The particle size may be 70 nm or less. The particle size may be 60 nm or less. The particle size may be 50 nm or less. In this case, the polishing composition may have an excellent polishing rate on the polished surface and stably adjust the frequency of defects generated on the polished surface.

[0065] The above average particle size refers to the average particle size of primary particles of the above polishing particles.

[0066] This embodiment can reduce the content of large particles in the polishing particles to below a predetermined level, thereby stably suppressing the generation of scratches on the polished surface, especially on the silicon oxide film, caused by the polishing particles.

[0067] The large particle counter (LPC) measurement of the polishing particles is performed using a particle size analyzer by applying the stock solution of the polishing composition. The measurement conditions are set as follows: the sensor model is LE400-05, the dilution factor is 1.53, the flow pump factor is 15 ml / min, and the sample vessel is 12 ml. Exemplarily, the particle size analyzer can be an Accusizer 780 model manufactured by Entegris.

[0068] The number of particles with a diameter exceeding 1 μm per unit volume of the polishing composition measured by a large particle counter (LPC) may be 80 or less per ml. The number of particles with a diameter exceeding 1 μm per unit volume of the polishing composition measured by a large particle counter (LPC) may be 70 or less per ml. The number of particles with a diameter exceeding 1 μm per unit volume of the polishing composition measured by a large particle counter (LPC) may be 40 or less per ml. The number of particles with a diameter exceeding 1 μm per unit volume of the polishing composition measured by a large particle counter (LPC) may be 30 or less per ml. The number of particles with a diameter exceeding 1 μm per unit volume of the polishing composition measured by a large particle counter (LPC) may be 0.8 or more per ml.

[0069] The number of particles having a diameter exceeding 5 μm per unit volume of the polishing composition measured by a large particle counter (LPC) may be 6 or less per ml. The number of particles having a diameter exceeding 5 μm per unit volume of the polishing composition measured by a large particle counter (LPC) may be 4 or less per ml. The number of particles having a diameter exceeding 5 μm per unit volume of the polishing composition measured by a large particle counter (LPC) may be 2.5 or less per ml. The number of particles having a diameter exceeding 5 μm per unit volume of the polishing composition measured by a large particle counter (LPC) may be 0.4 or more per ml.

[0070] The number of particles having a diameter exceeding 10 μm per unit volume of the polishing composition measured by a large particle counter (LPC) may be 2 particles / ml or less. The number of particles having a diameter exceeding 10 μm per unit volume of the polishing composition measured by a large particle counter (LPC) may be 1 particle / ml or less. The number of particles having a diameter exceeding 10 μm per unit volume of the polishing composition measured by a large particle counter (LPC) may be 0.1 particles / ml or more.

[0071] In this case, the number of defects occurring on the polished surface can be stably reduced to below a prescribed level.

[0072] In order to control the content of large particles in the polishing particles within a preset range in this embodiment, the filtered polishing particles can be applied to the polishing composition.

[0073] The filtration of the polishing particles may be performed through one filter. The filtration of the polishing particles may be performed through two or more filters.

[0074] When two or more filters are used, the filters may have pores of different sizes or may have pores of the same size.

[0075] The polishing particles may be filtered through a primary filter. The pore size of the primary filter may be 0.05 μm to 2 μm. The pore size may be greater than 0.08 μm. The pore size may be less than 1 μm. The pore size may be less than 0.5 μm. The pore size may be less than 0.3 μm.

[0076] The polishing particles may be filtered in the order of a primary filter and a secondary filter. The pore size of the secondary filter may be less than 0.9 times the pore size of the primary filter. The pore size of the secondary filter may be less than 0.8 times the pore size of the primary filter. The pore size of the secondary filter may be more than 0.3 times the pore size of the primary filter. The pore size of the secondary filter may be more than 0.5 times the pore size of the primary filter.

[0077] The polishing particles may be filtered in the order of a primary filter, a secondary filter and a tertiary filter. The pore size of the tertiary filter may be less than 1.5 times the pore size of the secondary filter. The pore size of the tertiary filter may be less than 1.2 times the pore size of the secondary filter. The pore size of the tertiary filter may be more than 0.5 times the pore size of the secondary filter. The pore size of the tertiary filter may be more than 0.8 times the pore size of the secondary filter.

[0078] The polishing particles may be additionally filtered through other filters after being filtered in the order of the primary filter, the secondary filter, and the tertiary filter.

[0079] Illustratively, the filter may be a filter manufactured by Saehan Green or a filter manufactured by MYCROPORE CORPORATION.

[0080] When the process of passing the polishing composition through the one or more filters is called one cycle, in this embodiment, the polishing particles can be filtered by passing the polishing composition through one or more cycles. In this embodiment, the polishing particles can be filtered by passing the polishing composition through two or more cycles. In this embodiment, the polishing particles can be filtered by passing the polishing composition through 10 cycles or less. In this embodiment, the polishing particles can be filtered by passing the polishing composition through 5 cycles or less.

[0081] In this case, it is possible to stably suppress the occurrence of defects on the surface of the silicon oxide film due to large particles during the polishing process.

[0082] Other additives

[0083] The semiconductor process polishing composition may further include other additives. The additives are not limited as long as they are generally applicable to the CMP field. For example, the additive may be at least any one of an oxidant, an acid component, a pH regulator, a dispersant, a polishing rate improver, a polishing regulator, a polishing pad protector, and a preservative.

[0084] The polishing composition for semiconductor processing may further include an oxidizing agent, which creates an environment that makes it easier to planarize the substrate surface by oxidizing metals such as tungsten, and plays a role in increasing the polishing rate and etching rate.

[0085] The oxidizing agent can be at least any one selected from the group consisting of hydrogen peroxide, urea hydrogen peroxide, urea, percarbonate, periodic acid, periodate, perchloric acid, perchlorate, perbromic acid, perbromate, perboric acid, perborate, permanganic acid, permanganate, persulfate, bromate, chlorate, chlorite, chromate, iodate, iodic acid, ammonium persulfate, benzoyl peroxide, calcium peroxide, barium peroxide, sodium peroxide and urea peroxide.

[0086] The semiconductor process polishing composition may contain 0.01 wt % to 5 wt % of an oxidizing agent. In this case, the composition may exhibit excellent polishing performance for metals and may suppress the formation of an oxide film on the polished metal during the polishing process.

[0087] The polishing composition for semiconductor process may further comprise an acid component. For example, the acid component may be 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, maleic 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.

[0088] The polishing composition for semiconductor process may further include a pH adjuster together with the acid component. For example, the pH adjuster may be any one selected from the group consisting of amines, aminomethyl propanol, tetramethyl ammonium hydroxide, potassium hydroxide, sodium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, sodium bicarbonate, sodium carbonate, imidazole and combinations thereof.

[0089] The polishing composition for semiconductor processing may further contain a dispersant.

[0090] The dispersant can prevent agglomeration between polishing particles in the polishing composition and disperse them uniformly. A cation-based dispersant can increase the Zeta potential of the polishing composition to a positive value, and an anion-based dispersant can reduce the Zeta potential of the polishing composition to a negative value.

[0091] The dispersant may include anionic low molecular weight, cationic high molecular weight, organic acid and the like.

[0092] The low molecular weight anion group of the dispersant may be at least one selected from oxalic acid, citric acid, polysulfonic acid, polyacrylic acid, polymethacrylic acid, and a combination thereof.

[0093] The cationic polymer of the dispersant can be at least one selected from polylysine, polyethyleneimine, benzethonium chloride, 5-bromo-5-nitro-1,3-dioxane (Bronidox), cetrimonium bromide, cetrimonium chloride, dimethyldioctadecyl ammonium bromide, tetramethylammonium hydroxide, distearyldimethylammonium chloride, poly(arylamine) and combinations thereof.

[0094] The organic acid of the dispersant may be at least any one selected from hydroxybenzoic acid, ascorbic acid, picolinic acid, glutamic acid, tryptophan, aminobutyric acid, and a combination thereof.

[0095] The polishing rate improver is an additive for improving the polishing rate of a substrate or wiring being polished, and may be at least any one selected from potassium nitrate, ferric nitrate, ammonium hydroxide, citric acid, acetic acid, and a combination thereof.

[0096] The polishing conditioner is used to minimize the adsorption of the polishing composition to the metal surface, and may include ammonium compounds, potassium nitrate, amino acids and salts thereof, and the like.

[0097] The polishing composition may further include a pH buffer to stabilize the pH of the polishing composition. The pH buffer may be an acetoxy compound.

[0098] The polishing composition for semiconductor process may contain a solvent, which may be water, and specifically, ultrapure water.

[0099] Physical properties of polishing compositions

[0100] The polishing selectivity ratio of the polishing composition for semiconductor process can be 1 to 5 for the silicon oxide film relative to the tungsten film.

[0101] The polishing selectivity ratio of the silicon oxide film relative to the tungsten film refers to the ratio of the polishing rate of the silicon oxide film by the polishing composition to the polishing rate of the tungsten film by the polishing composition.

[0102] In this embodiment, by controlling the polishing selectivity within a preset range in this embodiment, it is possible to more smoothly polish the surface of a substrate on which a tungsten pattern film having a fine pitch is formed. In particular, when polishing the surface of a substrate on which a tungsten pattern film and an insulating film are mixed, the polishing composition having the adjusted polishing selectivity can suppress over-polishing of the insulating film.

[0103] When measuring the polishing selectivity or polishing rate, the polishing conditions are set as follows: polishing time is 60 seconds, pressure applied to the wafer is 1.6 psi, pressure applied to the retaining ring is 2.4 psi, polishing head speed is 101 rpm, table speed is 100 rpm, and slurry supply rate is 200 ml / min. SK enpulse's HD-500C model can be used as a polishing pad. For example, CTS's AP-300 model can be used as a polishing machine.

[0104] The polishing selectivity of the semiconductor process polishing composition to the silicon oxide film with respect to the tungsten film may be 1 to 5. The polishing selectivity may be 1.3 or more. The polishing selectivity may be 1.5 or more. The polishing selectivity may be 2 or more. The polishing selectivity may be 4 or less. In this case, even when the surface of the substrate on which the fine tungsten pattern film is formed is polished, it can help to provide a polished surface in which defects are suppressed.

[0105] The polishing rate of the semiconductor process polishing composition for silicon oxide film may be 500 / min or more. The polishing rate may be 700 / min or more. The polishing rate may be 900 / min or more. The polishing rate may be 1,600 / min or less. The polishing rate may be 1,400 / min or less. The polishing rate may be 1,200 / min or less.

[0106] The polishing rate of the semiconductor process polishing composition for tungsten film may be 120 / min or more. The polishing rate may be 200 / min or more. The polishing rate may be 300 / min or more. The polishing rate may be 400 / min or more. The polishing rate may be 500 / min or more. The polishing rate may be 1,000 / min or less.

[0107] The Ra value of the tungsten film measured after polishing with the polishing composition for semiconductor process for 60 seconds may be 3 nm or less. The above Ra value may be 2 nm or less.

[0108] In this case, the above-mentioned polishing composition can provide a substrate including a fine tungsten pattern and having a smoother surface.

[0109] The Ra value is measured according to ISO 4287.

[0110] The conductivity of the polishing composition for semiconductor process may be 200 μS / cm or more. The conductivity may be 250 μS / cm or more. The conductivity may be 300 μS / cm or more. The conductivity may be 350 μS / cm or more. The conductivity may be 1000 μS / cm or less. In this case, it may help to smoothly carry out the oxidation reaction of the tungsten film. In addition, the polishing composition may help to polish the surface to be polished at an excellent polishing speed.

[0111] The pH of the semiconductor process polishing composition may be 1.5 to 4.5. The pH may be 2 or more. The pH may be 2.5 or more. The pH may be 4 or less. In this case, the degree of step difference between the tungsten film and the insulating film on the polished surface may be reduced to below a predetermined level by helping to improve the polishing performance of the polishing composition for the tungsten film.

[0112] The pH of the polishing composition is measured with a pH meter.

[0113] The zeta potential of the polishing composition for semiconductor processing may be +5 mV to +50 mV, may be above +10 mV, or may be below +40 mV.

[0114] The zeta potential of the polishing particles may be between +5 mV and +50 mV. The zeta potential may be above +10 mV. The zeta potential may be below +40 mV.

[0115] In this case, the polishing composition can exhibit good polishing performance on the substrate surface while exerting stable dispersibility.

[0116] The semiconductor process polishing composition may be a tungsten polishing composition. The tungsten polishing composition is used not only for polishing a substrate having only a tungsten film formed thereon, but also for polishing a substrate having a tungsten film mixed with a film of another material, i.e., a substrate having a tungsten pattern film formed thereon.

[0117] The polishing composition for semiconductor process may be a polishing composition for tungsten secondary polishing process. The description about tungsten secondary polishing process is repeated with the previous content, so the description will be omitted.

[0118] Method for manufacturing substrate

[0119] The method for manufacturing a substrate according to the present embodiment includes a process of polishing a substrate by applying the polishing composition for a semiconductor process as a slurry.

[0120] The substrate may include at least one of an insulating film, a metal wiring and a barrier layer on the substrate. 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.

[0121] Specifically, the process of polishing the substrate is as follows: while the substrate to be polished is brought into contact with the polishing pad together with the semiconductor process polishing composition supplied from a nozzle, the polishing head for fixing the substrate and the stage to which the polishing pad is attached are rotated.

[0122] If necessary, the process of polishing the substrate may further include a step of conditioning the surface of the polishing pad before polishing.

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

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

[0125] The process of polishing the substrate may be performed for 50 seconds to 10 minutes, however, it may vary depending on the desired degree of polishing.

[0126] The description of the above-mentioned polishing composition for semiconductor process overlaps with the previous content, so the description will be omitted.

[0127] The method for manufacturing a substrate may further include a washing process of washing the polished substrate.

[0128] The above-mentioned washing process can be performed by washing the polished substrate with pure water and inert gas.

[0129] The following examples are only provided to help understand the present invention, and the scope of the present invention is not limited thereto.

[0130] Preparation Example: Preparation of polishing composition

[0131] Example 1: In ultrapure water as a solvent, 3 wt% of colloidal silica surface-modified with 38 ppm (by weight) of (3-aminopropyl)triethoxysilane as polishing particles, 0.005 wt% of iron (III) nitrate enneahydrate as an iron ion compound, 0.012 wt% of malonic acid as an iron ion stabilizer, 0.0026 wt% of acetic acid as a pH buffer and 0.3 wt% of hydrogen peroxide as an oxidizing agent were added and mixed to prepare a polishing composition of a total of 100 wt%.

[0132] The polishing particles are applied to polishing particles that have been filtered twice. Specifically, the primary filter is a filter with a pore size of 0.1 μm from Saehan Green, the secondary filter is a filter with a pore size of 0.07 μm from Saehan Green, and the tertiary filter is a filter with a pore size of 0.07 μm from MYCROPORE CORPORATION. The polishing composition is filtered through the primary filter, the secondary filter, and the tertiary filter in sequence. The above filtration is performed twice in total to filter the polishing particles.

[0133] Example 2: A polishing composition of 100 wt % in total was prepared under the same conditions as in Example 1, except that 0.01 wt % of polyglycerol (excluding the corresponding weight of ultrapure water) was additionally added as a surfactant.

[0134] Example 3: A polishing composition of 100 wt% in total was prepared under the same conditions as in Example 1, except that the content of the suitable iron ion compound was 0.009 wt%.

[0135] Example 4: A polishing composition of 100 wt% in total was prepared under the same conditions as in Example 1, except that the content of the suitable iron ion compound was 0.014 wt%.

[0136] Comparative Example 1: A polishing composition of 100 wt % in total was prepared under the same conditions as in Example 1, except that the iron ion compound and the iron ion stabilizer were not used.

[0137] The contents of the components in the polishing compositions of the embodiments and comparative examples are shown in Table 1 below. The average diameter (primary particle size) of the polishing particles of Embodiment 1, the pH, zeta potential and conductivity of the polishing compositions are shown in Table 2 below.

[0138] Evaluation example: Polishing performance measurement

[0139] The polishing compositions of the embodiments and comparative examples were used to polish a 7000 μm thick tungsten film and a 2 μm thick silicon oxide film using a CTS AP-300 polisher. The tungsten film and silicon oxide film were formed on different wafers, each with a diameter of 300 mm.

[0140] The polishing conditions were set as follows: polishing time 60 seconds, pressure applied to the wafer 2.4 psi, pressure applied to the retaining ring 4.1 psi, polishing head speed 101 rpm, table speed 100 rpm, slurry supply rate 200 ml / min. SK enpulse's HD-500C model was used as the polishing pad.

[0141] The height differences between the tungsten pattern film and the silicon oxide film before and after polishing were measured on the polished wafer, and the polishing rates of the tungsten film and the silicon oxide film and the polishing selectivity of the silicon oxide film to the tungsten film were calculated based on the above values.

[0142] The measured values ​​and calculated values ​​of each of the above-mentioned Examples and Comparative Examples are shown in Table 3 below.

[0143] Evaluation example: LPC measurement and defect detection evaluation

[0144] The number of particles with a diameter greater than 1 μm, the number of particles with a diameter greater than 5 μm, and the number of particles with a diameter greater than 10 μm in the polishing compositions of Examples 1 and 2 were measured using an Accusizer 780 particle size analyzer manufactured by Entegris. When measuring the number of large particles, the polishing composition was placed in the particle size analyzer without dilution, the sensor model was set to LE400-05, the dilution factor was set to 1.53, the flow pump factor was set to 15 ml / min, and the sample container was set to 12 ml.

[0145] From the measured values ​​of each Example, the number of large particles per unit volume of the polishing composition was calculated.

[0146] Then, the wafer surface covered with the silicon oxide film was polished with the polishing composition of Example 1 and Example 2. The polishing conditions were set as follows: polishing time was 60 seconds, pressure applied to the wafer was 1.6 psi, pressure applied to the retaining ring was 2.4 psi, polishing head speed was 101 rpm, table speed was 100 rpm, and slurry supply speed was 200 ml / min. HD-500C model of SKenpulse was used as the polishing pad.

[0147] After washing the polished wafer surface with a brush, the number of defects detected on the wafer surface was measured.

[0148] Post-polishing defect inspection was performed twice for each example.

[0149] The measured values ​​for each example are reported in Table 4 below.

[0150] Evaluation example: Evaluation of whether there is tungsten protrusion

[0151] The surface of a wafer on which a tungsten pattern film and a silicon oxide film were formed was polished using the polishing composition of Example 1. The above-mentioned wafer was suitable for a wafer having a pattern density of 50%.

[0152] The polishing conditions were set as follows: polishing time 60 seconds, pressure applied to the wafer 2.4 psi, pressure applied to the retaining ring 4.1 psi, polishing head rotation speed 101 rpm, table rotation speed 100 rpm, slurry supply speed 200 ml / min. SK enpulse's HD-500C model was used as the polishing pad.

[0153] After polishing is completed, the cross section of the wafer is photographed and the height difference between the tungsten film and the silicon oxide film before and after polishing is measured. The polishing rate of the silicon oxide film, the polishing rate of the tungsten film and the polishing selectivity of the silicon oxide film relative to the tungsten film are calculated based on the height difference.

[0154] The calculated values ​​of polishing rate and polishing selectivity are recorded in Table 5 below.

[0155] Table 1

[0156]

[0157] Rs / i: Ratio of iron ion stabilizer content (by weight) to iron ion content (by weight)

[0158] Table 2

[0159]

[0160] Table 3

[0161]

[0162] Table 4

[0163]

[0164] Table 5

[0165]

[0166] With reference to Table 1 and Table 3, it can be confirmed that as the iron ion content increases, the polishing rate of the silicon oxide film decreases, while the polishing rate of the tungsten film increases.

[0167] Referring to Table 4, the number of large particles in Example 2 is significantly smaller than that in Example 1, and the number of defects on the polished surface is also smaller. This means that the surfactant plays a positive role in suppressing the formation of large particles in the polishing composition.

[0168] When the cross section of the wafer after polishing was observed, it was found that when the patterned wafer was polished using the polishing composition of Example 1, the step difference between the tungsten pattern film and the silicon oxide film was very small.

[0169] The preferred embodiments are described in detail above, but the scope of the present invention is not limited thereto. Various modifications and improvements by ordinary technicians in the technical field of the present invention using the basic concepts of the present embodiment defined in the scope of protection of the attached invention claims also fall within the scope of the present invention.

Claims

1. A polishing composition for semiconductor process, characterized in that: Containing: polishing particles; iron ions; and iron ion stabilizer; The above iron ion stabilizer contains two or more carboxyl groups. The above-mentioned polishing composition for semiconductor process has an electrical conductivity of 200 μs / cm to 800 μs / cm.

2. The semiconductor process polishing composition according to claim 1, characterized in that The iron ion stabilizer is any one selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid and combinations thereof.

3. The semiconductor process polishing composition according to claim 1, characterized in that The ratio of the content of the iron ion stabilizer to the content of the iron ions is 3 to 50 by weight.

4. The semiconductor process polishing composition according to claim 1, characterized in that The semiconductor process polishing composition comprises 1*10 -4 Weight% to 5*10 -3 % by weight of the above iron ions.

5. The semiconductor process polishing composition according to claim 1, characterized in that The above-mentioned polishing composition for semiconductor process further comprises a polyglyceryl compound.

6. The polishing composition for semiconductor process according to claim 5, characterized in that The polyglyceryl compound may have a weight average molecular weight of about 300 to about 1,200 g / mol.

7. The semiconductor process polishing composition according to claim 5, characterized in that The polishing composition for semiconductor process contains 0.001 wt % to 0.1 wt % of the polyglyceryl compound.

8. The semiconductor process polishing composition according to claim 1, wherein The polishing selectivity ratio of the silicon oxide film relative to the tungsten film is 1 to 5.

9. The semiconductor process polishing composition according to claim 1, characterized in that The pH is 1.5 to 4.

5.

10. The semiconductor process polishing composition according to claim 1, wherein The number of particles having a diameter exceeding 1 μm per unit volume measured by a large particle counter was 80 particles / ml or less.

11. A method for manufacturing a substrate, characterized in that: The method comprises a process of polishing a substrate by using the polishing composition for semiconductor process according to claim 1 as a slurry.

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