Polishing composition for semiconductor processes and method for manufacturing a substrate using the same

Abstract

To provide a polishing composition for semiconductor process that can polish the surface of a substrate containing a fine pitch tungsten pattern film to a smooth surface.SOLUTION: A polishing composition for semiconductor process according to one example includes abrasive particles, iron ions, and iron ion stabilizers. The iron ion stabilizer contains two or more carboxyl groups. The polishing composition for semiconductor process has an electrical conductivity of 200 μS / cm to 800 μS / cm.SELECTED DRAWING: None

Description

Technical Field

[0001] Embodiments relate to a polishing composition for semiconductor processes, a method for manufacturing a substrate using the same, and the like.

Background Art

[0002] As semiconductor devices are further miniaturized and densified, finer pattern formation technologies are being used. As a result, the surface structure of semiconductor devices has become more complex, and the step height of the interlayer film has also become larger. In manufacturing semiconductor devices, a chemical mechanical polishing (hereinafter referred to as "CMP") process is used as a planarization technology for removing steps in a specific film formed on a substrate.

[0003] In the CMP process, while slurry is supplied to a polishing pad, a substrate is pressurized and rotated to polish the surface. Depending on the stage of the process, the object to be planarized changes, and there are also differences in the physical properties of the slurry applied at this time.

[0004] After forming metal wiring, it is necessary to maintain sufficient polishing rate and polishing speed while minimizing dishing or erosion.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of embodiments is to provide a polishing composition for semiconductor processes that can smoothly polish the surface of a substrate including a tungsten pattern film with a fine pitch.

Means for Solving the Problems

[0007] A polishing composition for semiconductor processes according to one embodiment of this specification comprises polishing particles, iron ions, and an iron ion stabilizer.

[0008] The iron ion stabilizer contains two or more carboxyl groups.

[0009] The aforementioned polishing composition for semiconductor processes has an electrical conductivity of 200 μS / cm to 800 μS / cm.

[0010] The iron ion stabilizer may be any one selected from the group consisting of ethanedioic acid, propanedioic acid, butanedioic acid, pentanedioic acid, hexanedioic acid, heptanedioic acid, and combinations thereof.

[0011] The polishing composition for semiconductor processes may have a ratio of the content of the iron ion stabilizer (by weight) to the content of the iron ions (by weight) of 3 to 50.

[0012] The aforementioned polishing composition for semiconductor processes contains 1 × 10⁶ iron ions. -4 Weight%~5×10 -3 It can contain % by weight.

[0013] The aforementioned polishing composition for semiconductor processes may further contain a polyglycerin-based compound.

[0014] The weight-average molecular weight of the polyglycerin compound may be between 300 g / mol and 1,200 g / mol.

[0015] The aforementioned polishing composition for semiconductor processes may contain 0.001% to 0.1% by weight of the polyglycerin-based compound.

[0016] The aforementioned polishing composition for semiconductor processes may have a polishing selectivity ratio of 1 to 5 for silicon oxide film relative to tungsten film.

[0017] The aforementioned polishing composition for semiconductor processes may have a pH of 1.5 to 4.5.

[0018] The abrasive composition for semiconductor processes may have 80 particles / ml or less having a diameter greater than 1 μm as measured by LPC (Large particle counter) per unit volume.

[0019] The method for manufacturing a substrate according to another embodiment of the present specification includes a process of polishing the substrate by applying the abrasive composition for semiconductor processes as a slurry.

Advantages of the Invention

[0020] The abrasive composition for semiconductor processes according to the embodiment can smoothly polish the surface of a substrate including a tungsten pattern film with a fine pitch.

Best Mode for Carrying Out the Invention

[0021] Hereinafter, the embodiments will be described in detail so that those having ordinary knowledge in the technical field to which the embodiments belong can easily implement them. However, the embodiments can be realized in various different forms and are not limited to the embodiments described here.

[0022] As used herein, terms such as "about" and "substantially" are used in a meaning equal to or close to that numerical value when manufacturing and material tolerances inherent to the mentioned meaning are presented, and are used to prevent an infringer with bad faith from improperly using the disclosure in which an exact or absolute numerical value is mentioned to assist the understanding of the embodiment.

[0023] Throughout this specification, the term "these combinations" included in the Markush-type expressions means one or more mixtures or combinations selected from the group consisting of the components described in the Markush-type expressions, and means including one or more selected from the group consisting of the said components.

[0024] Throughout this specification, the description of "A and / or B" means "A, B, or A and B".

[0025] Throughout this specification, terms such as “First,” “Second,” or “A,” “B” are used to distinguish the same term from one another unless otherwise specified.

[0026] In this specification, the meaning of B being located on A means that B may be located on A, or another layer may be located between them while B is located on A, and is not limited to B being located in contact with the surface of A.

[0027] In this specification, unless otherwise specified, singular expressions are interpreted to include singular or plural, as interpreted in the context.

[0028] The term "~-type compound" includes "~-compound" and its derivatives. For example, polyglycerol-type compounds refer to polyglycerol compounds and derivatives of polyglycerol compounds.

[0029] The process of polishing the surface of a substrate containing a tungsten pattern film may be carried out in two steps, as follows: a primary tungsten polishing step to polish the tungsten bulk layer to expose the tungsten pattern film and the insulating layer, and a secondary tungsten polishing step to reduce the step difference between the tungsten pattern film and the insulating layer.

[0030] The smaller the pitch of the tungsten pattern film, the more frequently defects occur during the tungsten secondary polishing process. Specifically, defects such as increased step height in the contact pattern and misalignment with the upper contact pattern may occur more frequently.

[0031] The polishing composition in this example can provide a smooth and defect-free polished surface even when polishing the surface of a substrate containing a tungsten pattern film with a fine pitch.

[0032] The following provides a detailed explanation of specific examples.

[0033] Composition of polishing composition Iron ions and iron ion stabilizers The semiconductor process polishing composition described in the example comprises polishing particles, iron ions, and an iron ion stabilizer.

[0034] Iron ions can originate not only from general iron ionic compounds, but also from compounds containing iron ion complexes, iron ion compounds, and hydrates of iron ion complexes.

[0035] Iron ions can promote the oxidation of tungsten during the polishing process of tungsten pattern films. Furthermore, iron ions can contribute to the polishing composition having a controlled zeta potential. Through this, iron ions can prevent the polishing composition from over-polishing the insulating film, specifically the silicon oxide film. This improves the polishing properties of the polishing composition against tungsten films and suppresses the formation of steps on the polished substrate due to over-polishing of the silicon oxide film.

[0036] The iron ions may be divalent or trivalent.

[0037] The iron ions may, but are not limited to, those derived from, for example, iron chloride, iron nitrate, iron sulfate, iron perchlorate, iron acetate, iron citrate, Fe(III)-EDTA (Ethylenediaminetetraacetic Acid), etc.

[0038] On the other hand, iron ions can be relatively highly reactive within the polishing composition. Due to this property, iron ions may become reactants in side reactions without participating in the oxidation reaction of the tungsten film. Iron ion stabilizers can help stabilize iron ions within the polishing composition, allowing a larger number of iron ions to be used in the polishing process of the tungsten film.

[0039] The iron ion stabilizer may contain two or more carboxyl groups. These carboxyl groups can form coordination bonds with iron ions to regulate the reactivity of iron ions in the polishing composition.

[0040] The iron ion stabilizer may be any one selected from the group consisting of ethanedioic acid, propanedioic acid, butanedioic acid, pentanedioic acid, hexanedioic acid, heptanedioic acid, and combinations thereof.

[0041] In practice, the ratio of iron ions to iron ion stabilizers can be adjusted within a predetermined range. Through this, a sufficient number of iron ion compounds can be stabilized in the polishing composition, effectively improving the polishing properties of the polishing composition against tungsten films.

[0042] In a polishing composition for semiconductor processes, the ratio of the content of the iron ion stabilizer (by weight) to the content of iron ions (by weight) can be 3 to 50. The ratio may be 5 or more. The ratio may be 10 or more. The ratio may be 14 or more. The ratio may be 40 or less. The ratio may be 30 or less. In such cases, the iron ion stabilizer can sufficiently control the reactivity of iron ions in the polishing composition and can suppress the excessive lowering of the pH of the polishing composition by the iron ion stabilizer.

[0043] The polishing composition for semiconductor processes contains iron ions in a 1 × 10⁻⁶ -4 Weight%~5×10 -3 The abrasive composition may contain 3 × 10% by weight of iron ions. -4 The abrasive composition may contain more than 5% by weight of iron ions. -4 The abrasive composition may contain more than 4% by weight of iron ions. -3 The abrasive composition may contain less than 3% by weight of iron ions. -3It may contain less than 1% by weight. In this case, the polishing properties of the polishing composition for both the tungsten film and the silicon oxide film can be adjusted. Through this, the surface of a substrate containing a finely formed tungsten pattern film can be polished to be even smoother.

[0044] The iron ion content of a polishing composition for semiconductor processes can be measured by ICP-OES (Inductively coupled plasma optical emission spectroscopy).

[0045] Polyglycerol compounds The polishing composition for semiconductor processes may further contain a polyglycerin-based compound. The polyglycerin-based compound acts as a surfactant within the polishing composition, which can help to easily remove particles and polishing pad debris remaining on the substrate surface to be polished. In addition, the compound can help suppress the generation of scratches on the polished surface by preventing the polishing particles from aggregating with each other to form large particles during the polishing process.

[0046] The weight-average molecular weight of the polyglycerin compound may be 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 such cases, it is possible to prevent foreign matter from adsorbing onto the substrate surface to be polished, and to effectively improve the dispersibility of the polishing particles.

[0047] The weight-average molecular weight of polyglycerol compounds can be measured by GPC (Gel Permeation Chromatography).

[0048] The polishing composition may contain 0.001% to 0.1% by weight of a polyglycerin-based compound. The polishing composition may contain 0.003% or more by weight of a polyglycerin-based compound. The polishing composition may contain 0.005% or more by weight of a polyglycerin-based compound. The polishing composition may contain 0.07% or less by weight of a polyglycerin-based compound. The polishing composition may contain 0.05% or less by weight of a polyglycerin-based compound. The polishing composition may contain 0.03% or less by weight of a polyglycerin-based compound. In such cases, organic particles remaining on the substrate surface can be easily removed. Furthermore, it may help to reduce the number of defects occurring on the substrate surface to be polished to a certain level or lower.

[0049] abrasive particles The abrasive particles may include metal oxide particles and / or silicon oxide particles. The abrasive particles may also include silica. The abrasive particles may also include colloidal silica.

[0050] The abrasive particles may contain 70% by weight or more of colloidal silica. The abrasive particles may contain 80% by weight or more of colloidal silica. The abrasive particles may contain 90% by weight or more of colloidal silica. The abrasive particles may also be colloidal silica.

[0051] The abrasive particles may have a positive surface charge. The abrasive particles may be surface-modified to have a positive surface charge. The abrasive particles may be surface-modified with a compound having an amine group. The abrasive particles may be surface-modified with an aminosilane.

[0052] The aminosilane may be, for example, any one selected from the group consisting of 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]-1,2-ethylenediamine, N-[3-(triethoxysilyl)propyl]ethylenediamine, diethylenetriaminopropyltrimethoxysilane, diethylenetriaminopropylmethyldimethoxysilane, diethylaminomethyltriethoxysilane, diethylaminopropyltrimethoxysilane, diethylaminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, N-[3-(trimethoxysilyl)propyl]butylamine, and combinations thereof.

[0053] The polishing composition for semiconductor processes may contain 15 ppm (by weight) to 200 ppm (by weight) of aminosilane. The polishing composition may contain 20 ppm (by weight) or more of aminosilane. The polishing composition may contain 25 ppm (by weight) or more of aminosilane. The polishing composition may contain 30 ppm (by weight) or more of aminosilane. The polishing composition may contain 150 ppm (by weight) or less of aminosilane. The polishing composition may contain 100 ppm (by weight) or less of aminosilane. The polishing composition may contain 70 ppm (by weight) or less of aminosilane. The polishing composition may contain 50 ppm (by weight) or less of aminosilane. In such cases, the substrate surface to be polished can be polished even more smoothly, and improved dispersibility can be achieved. At the same time, the generation of surface modifier residue and its adsorption to the polished surface can be effectively suppressed.

[0054] A polishing composition for semiconductor processes may contain 1% to 10% by weight of polishing particles. A polishing composition for semiconductor processes may contain 2% or more by weight of polishing particles. A polishing composition for semiconductor processes may contain 8% or less by weight of polishing particles. A polishing composition for semiconductor processes may contain 5% or less by weight of polishing particles. In such cases, the polishing composition has an excellent polishing rate on the surface to be polished and can stably suppress the aggregation of polishing particles.

[0055] The average particle size of the abrasive particles may be 20 nm or more. The average particle size may be 30 nm or more. The average particle size may be 40 nm or more. The average particle size may be 70 nm or less. The average particle size may be 60 nm or less. The average particle size may be 50 nm or less. In such cases, the abrasive composition exhibits excellent polishing efficiency on the surface to be polished, and moreover, the frequency of defects occurring on the surface to be polished can be stably controlled.

[0056] The average particle size refers to the average particle size of the primary particles of the abrasive particles.

[0057] In practice, this method can reduce the content of large particles in the abrasive particles to below a certain level. Through this, it is possible to stably suppress the occurrence of scratches caused by abrasive particles, particularly on the silicon oxide film of the surface being polished.

[0058] The LPC (Large Particle Counter) measurement of abrasive particles is performed by applying the undiluted abrasive composition to a particle size analyzer. The measurement conditions are set to Sensor Model LE400-05, Dilution Factor 1.53, Flow Pump Factor 15 ml / min, and Sample Vessel 12 ml. For example, the Entegris Accusizer 780 model particle size analyzer can be used.

[0059] The abrasive composition may contain 80 or fewer particles per unit volume with a diameter greater than 1 μm as measured by an LPC (Large Particle Counter). The abrasive composition may contain 70 or fewer particles per unit volume with a diameter greater than 1 μm as measured by an LPC (Large Particle Counter). The abrasive composition may contain 40 or fewer particles per unit volume with a diameter greater than 1 μm as measured by an LPC (Large Particle Counter). The abrasive composition may contain 30 or fewer particles per unit volume with a diameter greater than 1 μm as measured by an LPC (Large Particle Counter). The abrasive composition may contain 0.8 or more particles per unit volume with a diameter greater than 1 μm as measured by an LPC (Large Particle Counter).

[0060] The abrasive composition may contain 6 or fewer particles per unit volume with a diameter greater than 5 μm as measured by an LPC (Large Particle Counter). The abrasive composition may contain 4 or fewer particles per unit volume with a diameter greater than 5 μm as measured by an LPC (Large Particle Counter). The abrasive composition may contain 2.5 or fewer particles per unit volume with a diameter greater than 5 μm as measured by an LPC (Large Particle Counter). The abrasive composition may contain 0.4 or more particles per unit volume with a diameter greater than 5 μm as measured by an LPC (Large Particle Counter).

[0061] The abrasive composition may contain 2 or fewer particles per unit volume with a diameter greater than 10 μm as measured by an LPC (Large Particle Counter). The abrasive composition may contain 1 or fewer particles per unit volume with a diameter greater than 10 μm as measured by an LPC (Large Particle Counter). The abrasive composition may contain 0.1 or more particles per unit volume with a diameter greater than 10 μm as measured by an LPC (Large Particle Counter).

[0062] In such cases, the number of defects generated on the polished surface can be stably reduced to below a certain level.

[0063] In order to control the content of large particles in the abrasive particles within a predetermined range in the concrete example, filtered abrasive particles can be applied to the abrasive composition.

[0064] Filtering of abrasive particles may be performed through one filter. Filtering of abrasive particles may be performed through two or more filters.

[0065] When two or more filters are applied, the filters may have gaps of different sizes from each other, or they may have gaps of the same size from each other.

[0066] The abrasive particles may be filtered through a primary filter. The size of the voids in the primary filter may be 0.05 μm to 2 μm. The size of the voids may be 0.08 μm or larger. The size of the voids may be 1 μm or smaller. The size of the voids may be 0.5 μm or smaller. The size of the voids may be 0.3 μm or smaller.

[0067] The abrasive particles may be filtered in the order of a primary filter and a secondary filter. The size of the voids in the secondary filter may be 0.9 times or less the size of the voids in the primary filter. The size of the voids in the secondary filter may be 0.8 times or less the size of the voids in the primary filter. The size of the voids in the secondary filter may be 0.3 times or more the size of the voids in the primary filter. The size of the voids in the secondary filter may be 0.5 times or more the size of the voids in the primary filter.

[0068] The abrasive particles may be filtered in the order of primary filter, secondary filter, and tertiary filter. The size of the voids in the tertiary filter may be 1.5 times or less the size of the voids in the secondary filter. The size of the voids in the tertiary filter may be 1.2 times or less the size of the voids in the secondary filter. The size of the voids in the tertiary filter may be 0.5 times or more the size of the voids in the secondary filter. The size of the voids in the tertiary filter may be 0.8 times or more the size of the voids in the secondary filter.

[0069] The abrasive particles are filtered through a primary filter, a secondary filter, and a tertiary filter in that order, and may then be filtered further by other filters.

[0070] For example, the filter may be one from SAEHANGREEN or MYCROPORE CORPORATION.

[0071] When one cycle is defined as the abrasive composition passing through each of the one or more filters mentioned above once, the embodiment can filter abrasive particles by circulating the abrasive composition for one or more cycles. The embodiment can filter abrasive particles by circulating the abrasive composition for two or more cycles. The embodiment can filter abrasive particles by circulating the abrasive composition for 10 cycles or less. The embodiment can filter abrasive particles by circulating the abrasive composition for 5 cycles or less.

[0072] In such cases, it is possible to reliably suppress the occurrence of defects on the surface of the silicon oxide film due to large particles during the polishing process.

[0073] Other additives Polishing compositions for semiconductor processes may further contain other additives. The additives are not limited as long as they are commonly used in the field of CMP (Chemical Polishing). Exemplarily, the additives may be at least one of the following: oxidizing agents, acidic components, pH adjusters, dispersants, polishing rate enhancers, polishing modifiers, polishing pad protectants, and preservatives.

[0074] Polishing compositions for semiconductor processes may further contain an oxidizing agent. The oxidizing agent plays a role in improving polishing and etching speeds by creating an environment in which the substrate surface can be planarized more easily by oxidizing metals such as tungsten.

[0075] 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, perchlorate, perbromic acid, perbromate, perboric acid, perborate, permanganic acid, permanganate, persulfate, bromate, chlorate, chlorite, chromate, iodate, iodic acid, ammonium sulfate peroxide, benzoyl peroxide, calcium peroxide, barium peroxide, sodium peroxide, and urea peroxide.

[0076] Polishing compositions for semiconductor processes may contain 0.01% to 5% by weight of an oxidizing agent. In such cases, the composition can exhibit excellent polishing properties for metals and can suppress the formation of oxide films on the metal being polished during the polishing process.

[0077] The polishing composition for semiconductor processes may further contain an acid component. The acid component may be at least one selected from the group consisting of hydrochloric acid, phosphoric acid, sulfuric acid, hydrofluoric acid, bromate, 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, as an example.

[0078] The polishing composition for semiconductor processes may further contain a pH adjuster along with the acid component. 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.

[0079] The polishing composition for semiconductor processes may further contain a dispersant.

[0080] Dispersants can prevent aggregation between abrasive particles within the abrasive composition and allow for uniform dispersion. Cationic dispersants can increase the zeta potential of the abrasive composition positively, while anionic dispersants can decrease the zeta potential of the abrasive composition negatively.

[0081] Dispersants may include anionic low molecular weights, cationic polymers, organic acids, etc.

[0082] The anionic low molecular weight dispersant may be one or more selected from oxalic acid, citric acid, polysulfonic acid, polyacrylic acid, polymethacrylic acid, and combinations thereof.

[0083] The cationic polymer of the dispersant may be one or more selected from polylysine, polyethyleneimine, benzethonium chloride, bronidox, cetrimonium bromide, cetrimonium chloride, dimethyldioctadecylammonium chloride, tetramethylammonium hydroxide, distearyldimethylammonium chloride, polyarylamine, and combinations thereof.

[0084] The dispersant organic acid may be one or more selected from hydroxylbenzoic acid, ascorbic acid, picolinic acid, glutamic acid, tryptophan, aminobutyric acid, and combinations thereof.

[0085] The polishing rate enhancer is an additive for increasing the polishing rate of the substrate or wiring to be polished, and may be one or more selected from potassium nitrate, iron nitrate, ammonium hydroxide, citric acid, acetic acid, and combinations thereof.

[0086] The polishing modifier is intended to minimize the adsorption of the polishing composition onto the metal surface and may include ammonium compounds, potassium nitrate, amino acids, and their salts.

[0087] The pH of the abrasive composition can be stabilized by further including a pH buffer. The pH buffer may be an acetic acid-based compound.

[0088] Polishing compositions for semiconductor processes may contain a solvent. The solvent may be water, and specifically ultrapure water.

[0089] Physical properties of abrasive compositions The polishing selectivity ratio of the silicon oxide film to the tungsten film in the semiconductor process polishing composition may be 1 to 5.

[0090] The polishing selectivity ratio of silicon oxide film to tungsten film refers to the ratio of the polishing rate of the silicon oxide film to the polishing rate of the tungsten film of the polishing composition.

[0091] The embodiment can help to further smooth the surface of a substrate on which a tungsten pattern film with a fine pitch is formed by controlling the polishing selectivity ratio within a range predetermined in the embodiment. In particular, the polishing composition with the adjusted polishing selectivity ratio can suppress excessive polishing of the insulating film when polishing the surface of a substrate on which a tungsten pattern film and an insulating film are mixed.

[0092] When measuring the polishing selectivity ratio or polishing rate, the polishing conditions are set as follows: polishing time 60 seconds, pressure applied to the wafer 1.6 psi, pressure applied to the retainer ring 2.4 psi, head rotation speed 101 rpm, table rotation speed 100 rpm, and slurry supply rate 200 ml / min. SK Empulse's HD-500C model can be used as the polishing pad. The polishing machine can, as an example, be the CTS AP-300 model.

[0093] The polishing selectivity ratio of the silicon oxide film to the tungsten film in the semiconductor process polishing composition may be 1 to 5. The polishing selectivity ratio may be 1.3 or higher. The polishing selectivity ratio may be 1.5 or higher. The polishing selectivity ratio may be 2 or higher. The polishing selectivity ratio may be 4 or lower. In such cases, it may be helpful to provide a polished surface with suppressed defect generation even when polishing the surface of a substrate on which a fine tungsten pattern film is formed.

[0094] The polishing rate of the semiconductor process polishing composition against silicon oxide film may be 500 Å / min or more. The polishing rate may be 700 Å / min or more. The polishing rate may be 900 Å / min or more. The polishing rate may be 1,600 Å / min or less. The polishing rate may be 1,400 Å / min or less. The polishing rate may be 1,200 Å / min or less.

[0095] The polishing rate of the semiconductor process polishing composition against a tungsten film may be 120 Å / min or more. The polishing rate may be 200 Å / min or more. The polishing rate may be 300 Å / min or more. The polishing rate may be 400 Å / min or more. The polishing rate may be 500 Å / min or more. The polishing rate may be 1,000 Å / min or less.

[0096] The Ra value of the tungsten film measured after polishing with a semiconductor process polishing composition for 60 seconds may be 3 nm or less. The Ra value may also be 2 nm or less.

[0097] In such cases, the polishing composition can provide a substrate having a smooth surface while also containing a tungsten fine pattern.

[0098] The Ra value is measured in accordance with ISO 4287.

[0099] The electrical conductivity of the semiconductor process polishing composition may be 200 μS / cm or higher. The electrical conductivity may be 250 μS / cm or higher. The electrical conductivity may be 300 μS / cm or higher. The electrical conductivity may be 350 μS / cm or higher. The electrical conductivity may be 1,000 μS / cm or lower. In such cases, it may help to facilitate the oxidation reaction of the tungsten film. Furthermore, the polishing composition can contribute to polishing the surface to be polished at an excellent polishing speed.

[0100] The pH of the polishing composition for semiconductor processes may be between 1.5 and 4.5. The pH may be 2 or higher. The pH may be 2.5 or higher. The pH may be 4 or lower. In such cases, it is particularly helpful to improve the polishing properties of the polishing composition for tungsten films, thereby reducing the degree to which a step difference occurs between the tungsten film and the insulating film on the surface to be polished to below a certain level.

[0101] The pH of the abrasive composition is measured using a pH meter.

[0102] The zeta potential of the semiconductor process polishing composition may be +5mV to +50mV. The zeta potential may be +10mV or higher. The zeta potential may be +40mV or lower.

[0103] The zeta potential of the polishing particles may be +5mV to +50mV. The zeta potential may be +10mV or higher. The zeta potential may be +40mV or lower.

[0104] In such cases, the polishing composition can exhibit stable dispersibility and excellent polishing properties on the substrate surface.

[0105] A polishing composition for semiconductor processes may be a tungsten polishing composition. A tungsten polishing composition refers to a polishing composition that is used not only for substrates on which only a tungsten film has been deposited, but also for substrates on which a tungsten film and films of other materials are mixed, i.e., substrates on which a tungsten pattern film or the like has been formed.

[0106] The polishing composition for semiconductor processes may be a polishing composition for tungsten secondary polishing processes. The explanation of the tungsten secondary polishing process will be omitted as it will overlap with the content described above.

[0107] Substrate manufacturing method The manufacturing method of the substrate in the embodiment includes a step of polishing the substrate by applying a semiconductor process polishing composition as a slurry.

[0108] The substrate may include at least one of an insulating film, metal wiring, and a barrier layer on its upper surface. The metal wiring may include copper or tungsten. If the metal wiring includes copper, the barrier layer may include tantalum and its nitride. If the metal wiring includes tungsten, the barrier layer may include titanium and its nitride.

[0109] Specifically, the process of polishing a substrate involves bringing the substrate to be polished into contact with a polishing pad together with a semiconductor process polishing composition supplied from a spray nozzle. This process can be carried out while the polishing head that holds the substrate in place rotates, and the platen to which the polishing pad is attached also rotates.

[0110] The process of polishing the substrate may further include, if necessary, a step of conditioning the surface of the polishing pad before polishing.

[0111] The polishing composition for semiconductor processes can penetrate toward the substrate while polishing the wafer in contact with the polishing pad.

[0112] During the process of polishing the substrate, a pressure of 6.89 kPa to 48.26 kPa may be applied. The aforementioned pressure may also be between 13.79 kPa and 34.47 kPa.

[0113] The process of polishing the substrate may be carried out for 50 seconds to 10 minutes. However, this can be adjusted depending on the desired degree of polishing.

[0114] The description of the aforementioned polishing composition for semiconductor processes will be omitted as it will be redundant with the content described above.

[0115] The method for manufacturing the substrate may further include a cleaning process for cleaning the substrate after polishing.

[0116] The cleaning process may be carried out by cleaning the polished substrate through purified water and an inert gas.

[0117] The following describes specific examples in more detail. The following examples are merely illustrative to aid in understanding the present invention, and the scope of the present invention is not limited thereto.

[0118] Manufacturing example: Manufacturing of abrasive compositions Example 1: A polishing composition totaling 100% by weight was prepared by adding and mixing ultrapure water as a solvent with 3% by weight of colloidal silica surface-modified with 38 ppm (by weight) (3-aminopropyl)triethoxysilane as abrasive particles, 0.005% by weight of iron(III) nitrate enneahydrate as an iron ion compound, 0.012% by weight of propanedioic acid as an iron ion stabilizer, 0.0026% by weight of acetic acid as a pH buffer, and 0.3% by weight of hydrogen peroxide as an oxidizing agent.

[0119] The abrasive particles used were those that had undergone two filtering cycles. Specifically, a filter with a void size of 0.1 μm from SAEHANGREEN was used as the primary filter, a filter with a void size of 0.07 μm from SAEHANGREEN was used as the secondary filter, and a filter with a void size of 0.07 μm from MYCROPORE CORPORATION was used as the tertiary filter. The abrasive composition was filtered by passing it through the primary, secondary, and tertiary filters in that order. The abrasive particles were filtered by performing the filtering process a total of two times.

[0120] Example 2: An abrasive composition totaling 100% by weight was prepared under the same conditions as in Example 1, except that an additional 0.01% by weight of polyglycerin was added as a surfactant (by removing the equivalent amount of ultrapure water).

[0121] Example 3: A polishing composition totaling 100% by weight was prepared under the same conditions as in Example 1, except that the iron ion compound content was 0.009% by weight.

[0122] Example 4: A polishing composition totaling 100% by weight was prepared under the same conditions as in Example 1, except that the content of the iron ion compound was 0.014% by weight.

[0123] Comparative Example 1: A total of 100% by weight of polishing composition was prepared under the same conditions as in Example 1, except that iron ion compounds and iron ion stabilizers were not applied.

[0124] The individual component content in the polishing compositions of each example and comparative example is shown in Table 1 below. The average diameter of the polishing particles (particle size of primary particles), pH of the polishing composition, zeta potential, and electrical conductivity of Example 1 are shown in Table 2 below.

[0125] Evaluation example: Measurement of polishing properties Polishing compositions for each example and comparative example were applied to polish a 7000 Å thick tungsten film and a 2 μm thick silicon oxide film using a CTS AP-300 polishing machine. The tungsten film and silicon oxide film were deposited on different wafers, and the wafer diameter was set to 300 mm for the application.

[0126] The polishing conditions were set as follows: polishing time 60 seconds, pressure applied to the wafer 2.4 psi, pressure applied to the retainer ring 4.1 psi, head rotation speed 101 rpm, table rotation speed 100 rpm, and slurry supply rate 200 ml / min. SK Empulse's HD-500C model was used as the polishing pad.

[0127] After polishing, the difference in height between the tungsten pattern film and the silicon oxide film before and after polishing was measured from the wafer. From these values, the polishing rates of the tungsten film and the silicon oxide film, and the polishing selectivity ratio of the silicon oxide film to the tungsten film were calculated.

[0128] The measured values ​​and calculated values ​​for each of the above examples and comparative examples are shown in Table 3 below.

[0129] Evaluation example: Evaluation of LPC measurement and defect detection 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 were measured from the polishing compositions of Example 1 and Example 2 using an Entegris Accusizer 780 model particle size analyzer. When measuring the number of large particles, the polishing composition was placed in the particle size analyzer without dilution, and the sensor model was set to LE400-05, dilution factor 1.53, flow pump factor 15 ml / min, and sample vessel 12 ml.

[0130] The number of large particles per unit volume of the abrasive composition was calculated from the measured values ​​for each example.

[0131] Subsequently, the surface of the wafer covered with a silicon oxide film was polished using the polishing compositions of Example 1 and Example 2. The polishing conditions were set as follows: polishing time 60 seconds, pressure applied to the wafer 1.6 psi, pressure applied to the retainer ring 2.4 psi, head rotation speed 101 rpm, table rotation speed 100 rpm, and slurry supply rate 200 ml / min. An SK Empulse HD-500C model was used as the polishing pad.

[0132] After polishing, the surface of the wafer was cleaned with a brush, and then the number of defects detected on the wafer surface was measured.

[0133] Defect detection after polishing was performed twice for each example.

[0134] The measured values ​​for each example are listed in Table 4 below.

[0135] Evaluation example: Evaluation of the presence or absence of tungsten protrusion. The surface of a wafer on which a tungsten pattern film and a silicon oxide film were formed was polished with the polishing composition of Example 1. The wafer used had a pattern density of 50%.

[0136] The polishing conditions were set as follows: polishing time 60 seconds, pressure applied to the wafer 2.4 psi, pressure applied to the retainer ring 4.1 psi, head rotation speed 101 rpm, table rotation speed 100 rpm, and slurry supply rate 200 ml / min. SK Empulse's HD-500C model was used as the polishing pad.

[0137] After polishing was completed, a cross-section of the wafer was photographed, and the difference in height between the tungsten film and the silicon oxide film before and after polishing was measured. From this height difference, the polishing rate of the silicon oxide film, the polishing rate of the tungsten film, and the polishing selectivity ratio of the silicon oxide film to the tungsten film were calculated.

[0138] The calculated values ​​for polishing rate and polishing selectivity are shown in Table 5 below.

[0139] [Table 1] Rs / i: Ratio of iron ion stabilizer content (by weight) to iron ion content (by weight)

[0140] [Table 2]

[0141] [Table 3]

[0142] [Table 4]

[0143] [Table 5]

[0144] Referring to Tables 1 and 3 above, it can be confirmed that as the iron ion content increases, the polishing rate of the silicon oxide film decreases and the polishing rate of the tungsten film increases.

[0145] Referring to Table 4, it was found that Example 2 had significantly fewer large particles and fewer defects on the polished surface compared to Example 1. This means that the surfactant contributes to suppressing the formation of large particles in the polishing composition.

[0146] When observing the cross-section of the polished wafer, it was found that when polishing a patterned wafer with the polishing composition of Example 1, the step difference between the tungsten pattern film and the silicon oxide film was minimal.

[0147] Although preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto. Various modifications and improvements by those skilled in the art, utilizing the basic concepts of the embodiments defined in the appended claims, also fall within the scope of the present invention.

Claims

1. It contains abrasive particles, iron ions, and an iron ion stabilizer. The iron ion stabilizer contains two or more carboxyl groups, It further contains polyglycerol compounds, A polishing composition for semiconductor processes having an electrical conductivity of 200 μS / cm to 800 μS / cm.

2. The polishing composition for semiconductor processes according to claim 1, wherein the iron ion stabilizer is one selected from the group consisting of ethanedioic acid, propanedioic acid, butanedioic acid, pentanedioic acid, hexanedioic acid, heptanedioic acid, and combinations thereof.

3. The semiconductor polishing composition according to claim 1, wherein the ratio of the content (by weight) of the iron ion stabilizer to the content (by weight) of the iron ions is 3 to 50.

4. The aforementioned iron ions are 1 × 10 －４ Weight%~5×10 －３ A polishing composition for semiconductor processes according to claim 1, comprising weight %.

5. The semiconductor polishing composition according to claim 1, wherein the weight-average molecular weight of the polyglycerin compound is 300 g / mol to 1,200 g / mol.

6. The semiconductor process polishing composition according to claim 1, comprising 0.001% to 0.1% by weight of the polyglycerin compound.

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

8. The semiconductor process polishing composition according to claim 1, wherein the pH is 1.5 to 4.

5.

9. The semiconductor process polishing composition according to claim 1, wherein the number of particles with a diameter of more than 1 μm per unit volume, as measured by LPC (Large particle counter), is 80 particles / ml or less.

10. A method for manufacturing a substrate, comprising the step of polishing a substrate by applying the semiconductor process polishing composition described in claim 1 as a slurry.

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