Polymer, polymer composition, polishing liquid set, polishing liquid, method for producing polishing liquid, and polishing method

Abstract

A polymer for a polishing liquid, wherein the polymer has a first structural unit derived from at least one styrene compound selected from the group consisting of styrene and styrene derivatives and a second structural unit derived from at least one methacrylic acid compound selected from the group consisting of methacrylic acid and salts thereof, and the content of the first structural unit is from more than 0 mol % to 38 mol %.

Description

Polymer, polymer composition, polishing liquid set, polishing liquid, method for producing polishing liquid, and polishing method

[0001] The present disclosure relates to a polymer, a polymer composition, a polishing liquid set, a polishing liquid, a method for producing a polishing liquid, a polishing method, and the like.

[0002] In recent years, processing techniques for achieving higher density and finer features have become increasingly important in the manufacturing process of semiconductor components. CMP (Chemical Mechanical Polishing), one of the processing techniques, is essential for forming STI, planarizing premetal insulating films or interlayer insulating films, forming plugs or buried metal wiring, and the like in the manufacturing process of semiconductor components. Known polishing solutions used in polishing processes such as CMP contain abrasive grains, a polymer, and an aqueous medium (see, for example, Patent Documents 1 to 3 listed below).

[0003] International Publication No. 2015 / 170436 Japanese Patent Application Laid-Open No. 2011-103498 International Publication No. 2007 / 055278

[0004] In some cases, the components of a polishing liquid are stored in a state where they are separated into a polymer composition (polymer-containing composition) containing a polymer and an aqueous medium for the polishing liquid and other components such as abrasive grains, and the polishing liquid is obtained by mixing the polymer composition with the other components. However, since sediment may occur after a certain time has passed since the preparation of a polymer composition containing a polymer and an aqueous medium for the polishing liquid, it is desired to improve the storage stability of the polymer composition.

[0005] Furthermore, in recent years, miniaturization of semiconductor components has accelerated, leading to thinner wiring widths and thinner films. This has led to stricter standards being required for semiconductor component manufacturing processes, creating a need for highly planarized substrates containing multiple insulating members. For example, in CMP techniques (such as CMP techniques for forming STI), a patterned wafer may be polished, which includes a substrate having a concave-convex pattern, a stopper (a member containing a stopper material) placed on the convex portions of the substrate, and an insulating member (a member containing an insulating material) placed on the substrate and the stopper to fill the concave portions of the substrate. In such polishing, polishing of the insulating member is stopped by the stopper, and polishing of the insulating member is stopped when the stopper is exposed. This is because it is difficult to artificially control the amount of polishing of the insulating member (e.g., the thickness removed from the insulating member). Therefore, the degree of polishing is controlled by polishing the insulating member until the stopper is exposed.

[0006] In CMP technology, after polishing an insulating material and stopping polishing when a stopper is exposed, additional polishing may be performed after the stopper is exposed to prevent the insulating material from remaining on the stopper. This additional polishing is called "over-polishing." Meanwhile, when over-polishing is performed, additional polishing may occur to insulating materials other than those remaining on the stopper (insulating materials embedded in recesses in the substrate). This may lead to the progression of dishing (a phenomenon in which insulating materials other than those remaining on the stopper (insulating materials embedded in recesses in the substrate) are excessively polished), resulting in poor flatness after polishing. Therefore, a polishing solution containing abrasive grains is required to suppress excessive dishing during over-polishing of a patterned wafer having protrusions and recesses.

[0007] An object of one aspect of the present disclosure is to provide a polymer that can be used to obtain a polymer composition having excellent storage stability as a polymer composition containing a polymer and an aqueous medium, and can also be used to obtain a polishing liquid that can suppress excessive dishing during over-polishing of a patterned wafer as a polishing liquid containing abrasive grains and a polymer. Another object of the present disclosure is to provide a polymer composition containing the polymer. Another object of the present disclosure is to provide a polishing liquid set including the polymer composition. Another object of the present disclosure is to provide a polishing liquid containing the polymer. Another object of the present disclosure is to provide a method for producing a polishing liquid using the polymer composition. Another object of the present disclosure is to provide a polishing method using the polishing liquid.

[0008] In some aspects, the present disclosure relates to the following [1] to

[12] , etc. [1] A polymer for use in a polishing liquid, the polymer having a first structural unit derived from at least one styrene compound selected from the group consisting of styrene and styrene derivatives, and a second structural unit derived from at least one methacrylic acid compound selected from the group consisting of methacrylic acid and salts thereof, and a content of the first structural unit being more than 0 mol% and not more than 38 mol%. [2] The polymer according to [1], wherein the first structural unit includes a structural unit derived from styrene. [3] The polymer according to [1] or [2], wherein the content of the second structural unit is 60 to 90 mol%. [4] The polymer according to [1] or [2], wherein the converted total amount of carboxy groups and carboxylate groups is 6.7 x 10 －３mol / g or more, and the converted total amount is calculated by replacing carboxylate groups in the polymer with carboxy groups. [5] The polymer according to any one of [1] to [4], having a weight-average molecular weight of 3,000 to 500,000. [6] A polymer composition containing the polymer according to any one of [1] to [5] and an aqueous medium. [7] A polishing liquid set comprising the polymer composition according to [6] and a liquid containing abrasive grains and an aqueous medium. [8] The polishing liquid set according to [7], wherein the abrasive grains comprise at least one oxide selected from the group consisting of cerium oxide, silicon oxide, aluminum oxide, zirconium oxide, and yttrium oxide. [9] A polishing liquid containing abrasive grains, the polymer according to any one of [1] to [5], and an aqueous medium.

[10] The polishing liquid according to [9], wherein the abrasive grains comprise at least one oxide selected from the group consisting of cerium oxide, silicon oxide, aluminum oxide, zirconium oxide, and yttrium oxide.

[11] A method for producing a polishing liquid, comprising a step of mixing the polymer composition according to [6] with a liquid containing abrasive grains and an aqueous medium.

[12] A polishing method, comprising a step of polishing a surface to be polished using the polishing liquid according to [9].

[0009] According to one aspect of the present disclosure, it is possible to provide a polymer composition containing a polymer and an aqueous medium, which has excellent storage stability, and a polishing liquid containing abrasive grains and a polymer, which can be used to obtain a polishing liquid that can suppress excessive dishing during over-polishing of a patterned wafer. According to another aspect of the present disclosure, it is possible to provide a polymer composition containing the polymer. According to another aspect of the present disclosure, it is possible to provide a polishing liquid set including the polymer composition. According to another aspect of the present disclosure, it is possible to provide a polishing liquid containing the polymer. According to another aspect of the present disclosure, it is possible to provide a method for producing a polishing liquid using the polymer composition. According to another aspect of the present disclosure, it is possible to provide a polishing method using the polishing liquid.

[0010] Hereinafter, embodiments of the present disclosure will be described in detail.

[0011] <Definition> In this specification, the term "polishing liquid" is defined as a composition that comes into contact with the surface to be polished during polishing. The term "polishing liquid" itself does not limit the components contained in the polishing liquid. As described below, the polishing liquid according to this embodiment may contain abrasive grains. Abrasive grains are also called "abrasive particles," but are referred to as "abrasive grains" in this specification. Abrasive grains are generally solid particles, and during polishing, it is thought that the object to be removed is removed by the mechanical action of the abrasive grains and the chemical action of the abrasive grains (mainly the surfaces of the abrasive grains), but the polishing mechanism is not limited.

[0012] As used herein, the term "process" refers not only to an independent process, but also to processes that cannot be clearly distinguished from other processes, as long as the process achieves its intended effect. Numerical ranges indicated using "to" indicate ranges that include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of a numerical range of another stage. In numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. Unless otherwise specified, the materials exemplified in this specification may be used alone or in combination of two or more types. When multiple substances corresponding to each component are present in the composition, the amount of each component in the composition refers to the total amount of the multiple substances present in the composition, unless otherwise specified. "Polishing rate" refers to the rate at which material is removed per unit time (removal rate = removal rate). "A or B" means that either A or B is included, or both are included. A numerical range of "A or more" means A and a range exceeding A. A numerical range of "A or less" means A and a range less than A. A "hydroxy group" does not include the OH structure contained in a carboxy group or a sulfo group (sulfonic acid group). A "carboxylate group" has a structure in which a carboxy group forms a salt, and includes -COONa, -COOK, -COONH ４The "main chain" of a polymer refers to the molecular chain that constitutes the longest molecular chain (e.g., a hydrocarbon chain) in the polymer, and the "side chain" refers to a molecular chain other than the main chain. The "aqueous medium" refers to water or a hydrophilic solvent that is miscible with water at 25°C.

[0013] In this specification, unless otherwise specified, the term "ethylenically unsaturated bond" refers to an ethylenically unsaturated bond having radical polymerizability. In the case of a polymer having a structural unit A derived from a compound A having an ethylenically unsaturated bond A, the chemical structure of the portion of the structural unit A of the polymer other than the portion corresponding to the ethylenically unsaturated bond A of the compound A is the same as the chemical structure of the portion of the compound A before polymerization other than the ethylenically unsaturated bond A. For example, a structural unit derived from styrene has a structure of "-CH ２ CH(C ６ H ５ (phenyl group))-" structure. In the case of a structural unit having an ionic functional group, even if ion exchange is performed after polymerization, the structural unit is referred to based on the structure of the polymer. For example, if the corresponding structural unit is converted to "-CH ２ When the structural unit is represented by "CH(COOH)-", this structural unit is referred to as "a structural unit derived from acrylic acid".

[0014] In this specification, the median diameter (D50) is the particle diameter of particles such as abrasive grains, which is the 50% particle diameter in a cumulative particle size distribution based on volume. The median diameter (D50) can be measured using a laser diffraction / scattering particle size distribution analyzer (manufactured by Microtrac-Bell Corporation, product name: Microtrac MT3300EXII) using a dispersion liquid (e.g., a polishing liquid) in which particles are dispersed in a liquid as a sample.

[0015] In this specification, the pH of a liquid (such as a solution or dispersion) can be measured under the following conditions: Measurement temperature: 25°C ± 0.5°C Measurement device: Model D-71 manufactured by HORIBA, Ltd. Measurement method: After two-point calibration using standard buffer solutions (phthalate pH buffer solution, pH: 4.01 (25°C); neutral phosphate pH buffer solution, pH: 6.86 (25°C)), the electrode is immersed in the liquid, and the pH can be measured using the above-mentioned measurement device after stabilization for at least three minutes.

[0016] <Polymer> The polymer according to this embodiment is a polymer for a polishing liquid (a polymer used as a component of a polishing liquid), and may be, for example, a polymer for a CMP polishing liquid (a polymer used as a component of a CMP polishing liquid). The polymer according to this embodiment has a first structural unit (a monomer unit of a styrene compound) derived from at least one styrene compound selected from the group consisting of styrene and styrene derivatives, and a second structural unit (a monomer unit of a methacrylic acid compound) derived from at least one methacrylic acid compound selected from the group consisting of methacrylic acid and its salts (salts of methacrylic acid). That is, the polymer according to this embodiment has a styrene compound and a methacrylic acid compound as monomer units. The content of the first structural unit in the polymer according to this embodiment is greater than 0 mol% and not more than 38 mol%. Hereinafter, the polymer according to this embodiment will sometimes be referred to as "polymer P."

[0017] According to the polymer P of this embodiment, it is possible to suppress the generation of sediment over time in a polymer composition (polymer-containing composition) containing the polymer P and an aqueous medium, and a polymer composition having excellent storage stability can be obtained. For example, according to the polymer P of this embodiment, as shown in the evaluation method (visual observation for the presence or absence of sediment) described in the Examples below, when the polymer composition is centrifuged after being kept at 60°C for 7 days (168 hours) after preparation, an evaluation result of A, B, or C can be obtained.

[0018] The pH of the polishing liquid is adjusted depending on the type of object to be polished, and may be adjusted, for example, to an acidic range. Therefore, when the components of the polishing liquid are stored separately from a polymer composition containing a polymer for the polishing liquid and other components such as abrasive grains, the pH of the polymer composition may also be adjusted to an acidic range so that the pH of the polishing liquid is adjusted to an acidic range when the polymer composition and other components are mixed. However, maintaining the pH of a polymer composition containing a polymer for the polishing liquid in an acidic range may result in the generation of sediment, and therefore it is necessary to improve the storage stability of polymer compositions having a pH in the acidic range. In contrast, according to one aspect of the polymer P of this embodiment, even when a polymer composition containing the polymer P and an aqueous medium has a pH in the acidic range (e.g., pH 4.0 or higher but less than 7.0), it is possible to suppress the generation of sediment over time, thereby obtaining a polymer composition with excellent storage stability. One aspect of the polymer P of this embodiment may be used in polymer compositions that do not have a pH in the acidic range, as long as it has the property of suppressing the generation of sediment over time when the polymer composition has a pH in the acidic range.

[0019] After a certain period of time has passed since the preparation of a polymer composition containing a polymer and an aqueous medium for use in a polishing liquid, the transmittance may decrease. In contrast, according to one aspect of the polymer P of this embodiment, it is possible to suppress the decrease in transmittance over time in a polymer composition containing the polymer P and an aqueous medium, thereby obtaining a polymer composition with even better storage stability. Furthermore, according to one aspect of the polymer P of this embodiment, even when the polymer composition containing the polymer P and an aqueous medium has a pH in the acidic range, the decrease in transmittance over time can be suppressed. For example, according to one aspect of the polymer P of this embodiment, as shown in the evaluation method (transmittance measurement) described in the Examples below, the supernatant obtained by centrifuging the polymer composition held at 60°C for 7 days (168 hours) after preparation can have a transmittance of, for example, 90% or more (preferably, 94% or more, 96% or more, 97% or more) at a wavelength of 700 nm.

[0020] According to the polymer P of this embodiment, a polishing liquid containing abrasive grains and polymer P can be obtained that can suppress excessive dishing during over-polishing of a patterned wafer. This allows the surface of the patterned wafer to be polished and planarized with high precision. For example, according to the polymer P of this embodiment, by using a polishing liquid containing abrasive grains and polymer P, excessive dishing can be suppressed during over-polishing of a portion of a patterned wafer where L / S = 20 / 80 μm (a pattern in which 20 μm-wide convex portions and 80 μm-wide concave portions are alternately arranged), and as shown by the evaluation method described in the examples below, the residual step amount in the portion of L / S = 20 / 80 μm can be reduced to, for example, 60 nm or less (preferably, 50 nm or less, 40 nm or less, 30 nm or less, 20 nm or less, etc.).

[0021] According to one aspect of the polymer P of this embodiment, by using a polishing liquid containing abrasive grains and polymer P, it is possible to suppress excessive dishing during over-polishing of a portion of a patterned wafer where L / S=50 / 50 μm (a pattern in which 50 μm-wide convex portions and 50 μm-wide concave portions are arranged alternately), and as shown by the evaluation method described in the examples below, the amount of residual step in the L / S=50 / 50 μm portion can be reduced to, for example, 30 nm or less (preferably, 20 nm or less, 10 nm or less, 5.0 nm or less, etc.).

[0022] According to one aspect of the polymer P of this embodiment, a polishing solution can be obtained that can suppress over-polishing of stoppers placed on convex portions during over-polishing of a patterned wafer. According to one aspect of the polymer P of this embodiment, by using a polishing solution containing abrasive grains and polymer P, over-polishing of stoppers can be suppressed during over-polishing of L / S = 20 / 80 μm portions of a patterned wafer. As shown by the evaluation method described in the Examples below, the amount of stopper polishing in the L / S = 20 / 80 μm portion can be reduced to, for example, 4.0 nm or less (preferably, 2.0 nm or less, 1.5 nm or less, etc.). According to one aspect of the polymer P of this embodiment, by using a polishing solution containing abrasive grains and polymer P, over-polishing of stoppers can be suppressed during over-polishing of L / S = 50 / 50 μm portions of a patterned wafer. As shown by the evaluation method described in the Examples below, the amount of stopper polishing in the L / S = 50 / 50 μm portion can be reduced to, for example, 1.0 nm or less (preferably, 0.5 nm or less, 0.3 nm or less, etc.).

[0023] According to one aspect of the polymer P of this embodiment, by using a polishing liquid containing abrasive grains and polymer P, in a pattern wafer having a substrate with a concave-convex pattern, a stopper (a member containing a stopper material) placed on the convex portions of the substrate, and an insulating member (a member containing an insulating material) placed on the substrate and the stopper so as to fill the concave portions of the substrate, when the stopper material is silicon nitride and the insulating material is silicon oxide, excessive dishing can be suppressed during over-polishing, and over-polishing of the stopper can be suppressed during over-polishing.

[0024] The polymer P according to this embodiment has a first structural unit derived from at least one styrene compound selected from the group consisting of styrene and styrene derivatives. The first structural unit may contain a structural unit derived from styrene, from the viewpoint of easily suppressing excessive dishing (e.g., easily suppressing excessive dishing during over-polishing of a patterned wafer (unless otherwise specified, any patterned portion such as a portion with an L / S of 20 / 80 μm or a portion with an L / S of 50 / 50 μm) using a polishing liquid containing abrasive grains and the polymer P; the same applies hereinafter) or easily suppressing over-polishing of a stopper (e.g., easily suppressing over-polishing of a stopper during over-polishing of a patterned wafer (unless otherwise specified, any patterned portion such as a portion with an L / S of 20 / 80 μm or a portion with an L / S of 50 / 50 μm) using a polishing liquid containing abrasive grains and the polymer P; the same applies hereinafter).

[0025] The solubility of the styrene compound in water at 25°C may be in the following range. From the viewpoint of easily suppressing excessive dishing or easily suppressing over-polishing of the stopper, the solubility of the styrene compound may be 0.1 g / 100 mL or less, 0.05 g / 100 mL or less, or 0.03 g / 100 mL or less. From the viewpoint of easily obtaining excellent storage stability of the polymer composition, the solubility of the styrene compound may be 0.01 g / 100 mL or more, 0.02 g / 100 mL or more, or 0.025 g / 100 mL or more. From these viewpoints, the solubility of the styrene compound may be 0.01 to 0.1 g / 100 mL. The solubility of styrene in water at 25°C is 0.03 g / 100 mL.

[0026] Examples of styrene derivatives include alkylstyrenes (such as α-methylstyrene), alkoxystyrenes (such as α-methoxystyrene and p-methoxystyrene), m-chlorostyrene, trimethylsilylstyrene, 4-carboxystyrene, and styrenesulfonic acid. From the viewpoint of easily suppressing excessive dishing or easily suppressing over-polishing of the stopper, the styrene derivative may contain at least one compound selected from the group consisting of hydrocarbon compounds and compounds in which at least one hydrogen atom contained in a hydrocarbon compound has been substituted with a halogen atom, or may contain a hydrocarbon compound. The first structural unit in polymer P may be an embodiment comprising a structural unit derived from at least one compound selected from the group consisting of hydrocarbon compounds and compounds in which at least one hydrogen atom contained in a hydrocarbon compound has been substituted with a halogen atom, or may be an embodiment comprising a structural unit derived from a hydrocarbon compound.

[0027] The styrene derivative does not need to have a hydrophilic structure, from the viewpoint of easily suppressing excessive dishing or over-polishing of the stopper. Examples of the hydrophilic structure include a polyether group, a hydroxy group, a carboxy group, a carboxylate group, a sulfonic acid group, and an amino group.

[0028] The content (content) of the first structural unit in polymer P is 38 mol% or less, based on the total amount of structural units constituting polymer P, from the viewpoint of obtaining excellent storage stability of the polymer composition. From the viewpoint of easily obtaining excellent storage stability of the polymer composition, easily suppressing excessive dishing, or easily suppressing over-polishing of the stopper, the content of the first structural unit may be 35 mol% or less, 32 mol% or less, 30 mol% or less, 28 mol% or less, 25 mol% or less, 22 mol% or less, 20 mol% or less, 18.5 mol% or less, 18 mol% or less, or 17 mol% or less. The content of the first structural unit may be 16 mol% or less, 15.5 mol% or less, 15 mol% or less, less than 15 mol%, 14.5 mol% or less, or 14 mol% or less. From the viewpoint of easily suppressing excessive dishing during over-polishing of a portion of a patterned wafer where L / S = 20 / 80 μm, or from the viewpoint of easily suppressing over-polishing of a stopper, the content (content rate) of the first structural unit in polymer P is more than 0 mol% based on the total amount of structural units constituting polymer P. From the viewpoint of easily obtaining excellent storage stability of the polymer composition, easily suppressing excessive dishing, or easily suppressing over-polishing of a stopper, the content of the first structural unit may be 1.0 mol% or more, 3.0 mol% or more, 5.0 mol% or more, 7.0 mol% or more, 9.0 mol% or more, 10 mol% or more, 11 mol% or more, 13 mol% or more, 14 mol% or more, 14.5 mol% or more, 15 mol% or more, 15.5 mol% or more, 16 mol% or more, or 17 mol% or more. The content of the first structural unit may be 18 mol% or more, 18.5 mol% or more, 20 mol% or more, 22 mol% or more, 25 mol% or more, 28 mol% or more, or 30 mol% or more. From these viewpoints, the content of the first structural unit in polymer P may be more than 0 mol% and 35 mol% or less, 1.0 to 38 mol%, 5.0 to 38 mol%, 7.0 to 35 mol%, 9.0 to 32 mol%, 11 to 25 mol%, 13 to 25 mol%, or 15.5 to 18.5 mol%.When polymer P has structural units derived from styrene and structural units derived from a styrene derivative, the content of the first structural units is the total amount of the structural units derived from styrene and the structural units derived from a styrene derivative.

[0029] The polymer P according to this embodiment has a second structural unit derived from at least one methacrylic acid compound selected from the group consisting of methacrylic acid and its salts. Examples of the salt of methacrylic acid include alkali metal salts (sodium salt, potassium salt, etc.) and ammonium salts. The second structural unit may contain a structural unit derived from methacrylic acid, from the viewpoint of easily achieving excellent storage stability of the polymer composition, easily suppressing excessive dishing, or easily suppressing overpolishing of the stopper.

[0030] The content (content rate) of the second structural unit in polymer P may be less than 100 mol%, 99 mol% or less, 97 mol% or less, 95 mol% or less, 93 mol% or less, 91 mol% or less, 90 mol% or less, 89 mol% or less, 87 mol% or less, 86 mol% or less, 85.5 mol% or less, 85 mol% or less, 84.5 mol% or less, 84 mol% or less, or 83 mol% or less, based on the total amount of structural units constituting polymer P, from the viewpoint of easily obtaining excellent storage stability of the polymer composition, easily suppressing excessive dishing, or easily suppressing over-polishing of the stopper. The content of the second structural unit may be 82 mol% or less, 81.5 mol% or less, 80 mol% or less, 78 mol% or less, 75 mol% or less, 72 mol% or less, 70 mol% or less, 68 mol% or less, 65 mol% or less, 62 mol% or less, 60 mol% or less, 50 mol% or less, 40 mol% or less, 30 mol% or less, 20 mol% or less, 15 mol% or less, 12 mol% or less, or 10 mol% or less. The content (content rate) of the second structural unit in polymer P is more than 0 mol% from the viewpoint of obtaining excellent storage stability of the polymer composition and from the viewpoint of suppressing excessive dishing during overpolishing of a portion of a patterned wafer where L / S = 20 / 80 μm. From the viewpoint of easily obtaining excellent storage stability of the polymer composition, easily suppressing excessive dishing, or easily suppressing over-polishing of the stopper, the content of the second structural unit may be 1.0 mol% or more, 3.0 mol% or more, 5.0 mol% or more, 7.0 mol% or more, 9.0 mol% or more, 10 mol% or more, 20 mol% or more, 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, 62 mol% or more, 65 mol% or more, 68 mol% or more, 70 mol% or more, 72 mol% or more, 75 mol% or more, 78 mol% or more, 80 mol% or more, 81.5 mol% or more, 82 mol% or more, or 83 mol% or more. The content of the second structural unit may be 84 mol % or more, 84.5 mol % or more, 85 mol % or more, 85.5 mol % or more, or 86 mol % or more.From these viewpoints, the content of the second structural unit in polymer P may be more than 0 mol% and less than 100 mol%, 65 mol% or more and less than 100 mol%, 62 to 99 mol%, 5.0 to 95 mol%, 7.0 to 95 mol%, 9.0 to 95 mol%, 50 to 93 mol%, 60 to 90 mol%, 65 to 91 mol%, 68 to 89 mol%, 75 to 87 mol%, or 81.5 to 85.5 mol%. When polymer P has a structural unit derived from methacrylic acid and a structural unit derived from a salt of methacrylic acid, the content of the second structural unit is the total amount of the structural unit derived from methacrylic acid and the structural unit derived from a salt of methacrylic acid.

[0031] At least one selected from the group consisting of the first structural unit and the second structural unit may be contained in the main chain of the polymer P, or may be contained in a side chain of the polymer P. The main chain of the polymer P may contain at least one selected from the group consisting of the first structural unit and the second structural unit, or may contain the first structural unit and the second structural unit, from the viewpoint of easily achieving excellent storage stability of the polymer composition, easily suppressing excessive dishing, or easily suppressing over-polishing of the stopper.

[0032] The total amount of the first structural unit and the second structural unit may be 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, 97% by mass or more, 98% by mass or more, or 99% by mass or more, based on the total mass of the structural units constituting the polymer P, from the viewpoint of easily obtaining excellent storage stability of the polymer composition, easily suppressing excessive dishing, or easily suppressing over-polishing of the stopper. The structural units constituting the polymer P may be substantially composed of the first structural unit and the second structural unit (an embodiment in which substantially 100% by mass of the structural units constituting the polymer P are the first structural unit and the second structural unit).

[0033] The molar ratio A of the content of the second structural unit to the content of the first structural unit (ratio of substance amounts: content of second structural unit / content of first structural unit) may be in the following range. From the viewpoint of easily obtaining excellent storage stability of the polymer composition, easily suppressing excessive dishing, or easily suppressing over-polishing of the stopper, the molar ratio A may be 0.10 or more, 0.30 or more, 0.50 or more, 0.80 or more, 1.0 or more, 2.0 or more, 2.5 or more, 3.0 or more, 3.5 or more, 4.0 or more, or 4.5 or more. The molar ratio A may be 5.0 or more, 5.5 or more, or 6.0 or more. From the viewpoint of easily obtaining excellent storage stability of the polymer composition, easily suppressing excessive dishing, or easily suppressing over-polishing of the stopper, the molar ratio A may be 10 or less, 9.0 or less, 8.0 or less, 7.0 or less, 6.5 or less, 6.0 or less, 5.5 or less, or 5.0 or less. The molar ratio A may be 4.5 or less, 4.0 or less, 3.5 or less, 3.0 or less, 2.5 or less, 2.0 or less, 1.0 or less, 0.80 or less, 0.50 or less, or 0.40 or less. From these viewpoints, the molar ratio A may be 0.10 to 10, 2.0 to 10, 4.5 to 10, 0.10 to 6.5, 2.0 to 6.5, 4.5 to 6.5, 0.10 to 5.5, 2.0 to 5.5, or 4.5 to 5.5.

[0034] The polymer P may have a structural unit derived from other monomers polymerizable with a styrene compound or a methacrylic acid compound (monomers other than styrene compounds and methacrylic acid compounds). As such a monomer, a polymerizable vinyl compound can be used, and examples of such a monomer include acrylic acid, (meth)acrylic acid alkyl esters (methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, etc.), heterocyclic vinyl compounds (vinylpyrrolidone, etc.), hydroxy Alkyl (meth)acrylates (2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, etc.), polyalkylene glycol (meth)acrylates (ethylene glycol (meth)acrylate, butylene glycol (meth)acrylate, etc.), alkylamino (meth)acrylates (N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, etc.), vinyl ester compounds (vinyl formate, vinyl acetate, vinyl propionate, vinyl versatility acid (for example, trade name: VeoVa 10, Hexion Specialty Chemicals), etc.), monoolefin compounds (ethylene, propylene, butylene, isobutylene, etc.), conjugated diolefin compounds (butadiene, isoprene, chloroprene, etc.), α,β-unsaturated mono- or dicarboxylic acids other than acrylic acid and methacrylic acid (crotonic acid, citraconic acid, maleic acid, itaconic acid, maleic anhydride, fumaric acid, etc.), carboxy group-containing vinyl compounds (monohydroxyethyl phthalate (meth)acrylate, monohydroxypropyl oxalate (meth)acrylate, etc.), amine imide group-containing vinyl compounds (1,1,1-trimethylamine methacrylimide, etc.), cyanide vinyl compounds (acrylonitrile, methacrylonitrile, etc.), amide group- or substituted amide group-containing α,β-ethylenically unsaturated compounds ((meth)acrylamide, N-methylacrylamide, N,N-dimethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, etc.), carbonyl group-containing α,β-ethylenically unsaturated compounds (acrolein, diacetone acrylamide, vinyl methyl ketone, diacetone acrylate, acetonitrile acrylate, etc.), sulfonic acid group-containing α,β-ethylenically unsaturated compounds (allyl sulfonate, sodium p-styrenesulfonate, etc.), etc.

[0035] The polymer P according to this embodiment may have a third structural unit derived from at least one selected from the group consisting of carboxylic acids other than methacrylic acid and salts thereof. Examples of carboxylic acids other than methacrylic acid include acrylic acid, maleic acid, itaconic acid, and other carboxylic acids having an ethylenically unsaturated bond. The content of the second structural unit in the polymer P having the third structural unit is greater than 0 mol% based on the total mass of the structural units constituting the polymer P, from the viewpoint of obtaining excellent storage stability of the polymer composition and suppressing excessive dishing during over-polishing of the L / S = 20 / 80 μm portion of a patterned wafer using a polishing liquid containing abrasive grains and the polymer P. From the viewpoint of easily obtaining excellent storage stability of the polymer composition, easily suppressing excessive dishing, or easily suppressing over-polishing of the stopper, the content may be 1.0 mol% or more, 3.0 mol% or more, 5.0 mol% or more, 7.0 mol% or more, 9.0 mol% or more, or 10 mol% or more. The content of the second structural unit in the polymer P having the third structural unit may be within the above-mentioned ranges, for example, 30 mol% or less, 20 mol% or less, 15 mol% or less, 12 mol% or less, or 10 mol% or less, based on the total mass of the structural units constituting the polymer P. The content of the first structural unit in the polymer P having the third structural unit may be within the above-mentioned ranges.

[0036] In the polymer P according to this embodiment, the content B of structural units derived from at least one selected from the group consisting of acrylic acid and maleic acid (the total amount of structural units derived from acrylic acid and structural units derived from maleic acid) may be in the following ranges based on the total mass of the structural units constituting the polymer P. The content B may be 70 mol% or less, 60 mol% or less, 50 mol% or less, 40 mol% or less, less than 40 mol%, 30 mol% or less, 20 mol% or less, 10 mol% or less, 5 mol% or less, or 1 mol% or less. The content B may be 0 mol% or more, or more than 0 mol%.

[0037] In the polymer P according to the present embodiment, the content of structural units derived from a monomer having at least one selected from the group consisting of a sulfonic acid group and a sulfonate salt group may be 5 mol % or less, less than 5 mol %, 1 mol % or less, or 0 mol % or less, or may be 0 mol %.

[0038] In the polymer P according to this embodiment, the content of structural units derived from acrylonitrile may be 10 mol% or less, less than 10 mol%, 5 mol% or less, 1 mol% or less, or 0 mol% or less, and may be 0 mol%.

[0039] The content of the structural units constituting the polymer P is １３ Specifically, the content of the structural units constituting the polymer P can be measured by C-NMR. ＴＭ Using a Bruker Avance NEO400 Onebay equipped with a 5mm (BBO type) １３ It can be measured by C-NMR (resonance frequency: 100 MHz, measurement temperature: 25°C, relaxation waiting time: 4 seconds). The content of the structural unit can be adjusted by adjusting the amount of each monomer used and the timing of addition during the synthesis of polymer P.

[0040] The total amount C of carboxy groups and carboxylate salt groups in the polymer P according to this embodiment may be in the following range based on the total amount of the polymer P. The total amount C is set to 6.5×10 from the viewpoint of easily obtaining good solubility of the polymer P in an aqueous medium, easily obtaining excellent storage stability of the polymer composition, easily suppressing excessive dishing, or easily suppressing over-polishing of the stopper. －３ mol / g or more, 6.7×10 －３ mol / g or more, 7.0×10 －３ mol / g or more, 7.4×10 －３ mol / g or more, 7.5×10 －３ mol / g or more, 8.0×10 －３ mol / g or more, 8.3×10 －３ mol / g or more, 8.5×10 －３ mol / g or more, 9.0×10 －３ mol / g or more, 9.1×10 －３ mol / g or more, or 9.3 x 10 －３ The converted total amount C may be 9.5 × 10 －３ The converted total amount C may be 1.1 × 10 mol / g or more from the viewpoint of easily adjusting the pH of the polymer composition or the polishing liquid, easily obtaining excellent storage stability of the polymer composition, easily suppressing excessive dishing, or easily suppressing over-polishing of the stopper. －２ mol / g or less, 1.0×10 －２ mol / g or less, 9.8×10 －３ mol / g or less, 9.5×10 －３ mol / g or less, or 9.3 x 10 －３ The converted total amount C may be 9.1 × 10 －３ mol / g or less, 9.0×10 －３ mol / g or less, 8.5×10 －３ mol / g or less, 8.3×10 －３ mol / g or less, or 8.0 x 10 －３ From these viewpoints, the converted total amount C may be 6.5 × 10 －３ ~1.1 x 10 －２ mol / g, 6.5×10 －３ ~9.8 x 10－３ mol / g, 6.5×10 －３ ~9.5 x 10 －３ mol / g, 7.5×10 －３ ~1.1 x 10 －２ mol / g, 7.5×10 －３ ~9.8 x 10 －３ mol / g, 7.5×10 －３ ~9.5 x 10 －３ mol / g, 9.0×10 －３ ~1.1 x 10 －２ mol / g, 9.0×10 －３ ~9.8 x 10 －３ mol / g, or 9.0 x 10 －３ ~9.5 x 10 －３ The total amount C of carboxyl groups and carboxylate salt groups is calculated by replacing the carboxylate salt groups in the polymer with carboxyl groups, and specifically, can be calculated by the method described in the examples.

[0041] The weight-average molecular weight of polymer P may be in the following ranges from the viewpoint of easily obtaining excellent storage stability of the polymer composition, easily suppressing excessive dishing, or easily suppressing over-polishing of the stopper. The weight-average molecular weight may be 500,000 or less, 300,000 or less, 200,000 or less, 100,000 or less, 80,000 or less, 60,000 or less, 50,000 or less, 45,000 or less, 43,000 or less, 42,000 or less, 40,000 or less, or 39,000 or less. The weight-average molecular weight may be 3,000 or more, 5,000 or more, 10,000 or more, 20,000 or more, more than 20,000, 30,000 or more, 35,000 or more, 39,000 or more, 40,000 or more, 42,000 or more, or 43,000 or more. From these viewpoints, the weight average molecular weight of polymer P may be 3,000 to 500,000, 3,000 to 100,000, 3,000 to 50,000, 30,000 to 500,000, 30,000 to 100,000, 30,000 to 50,000, 40,000 to 500,000, 40,000 to 100,000, or 40,000 to 50,000. The weight average molecular weight (Mw) is a pullulan-equivalent value measured by gel permeation chromatography (GPC), and specifically, can be measured by the method described in the examples.

[0042] <Polymer composition> The polymer composition (polymer-containing composition) according to this embodiment contains a polymer P and an aqueous medium. In the polymer composition according to this embodiment, one type of polymer P may be used alone, or two or more types may be used in combination. For example, as the two or more types of polymers P, polymers P having different contents of structural units (first structural units, second structural units, etc.) may be used, or polymers P having different types of structural units (first structural units, second structural units, etc.) may be used. The polymer composition according to this embodiment does not need to contain abrasive grains.

[0043] In the polymer composition, at least a portion (partial or all) of the polymer P may be dissolved in the aqueous medium. The proportion of the polymer P dissolved in the aqueous medium in the polymer composition is not particularly limited, but may be 90% by mass or more, 95% by mass or more, or 99% by mass or more.

[0044] The content of polymer P in the polymer composition may be in the following ranges based on the total mass of the polymer composition. From the viewpoint of easily suppressing excessive dishing or easily suppressing over-polishing of the stopper, the content of polymer P may be 0.010 mass% or more, 0.050 mass% or more, 0.10 mass% or more, 0.50 mass% or more, 1.0 mass% or more, 2.0 mass% or more, or 3.0 mass% or more. From the viewpoint of easily suppressing sedimentation of polymer P and improving storage stability, the content of polymer P may be 30 mass% or less, 20 mass% or less, 10 mass% or less, 5.0 mass% or less, 4.0 mass% or less, or 3.0 mass% or less. From these viewpoints, the content of polymer P may be 0.010 to 30 mass%, 0.10 to 20 mass%, 1.0 to 10 mass%, or 2.0 to 5.0 mass%.

[0045] The aqueous medium may contain water and may contain a hydrophilic solvent that is miscible with water at 25° C. Examples of hydrophilic solvents include, but are not limited to, alcohols such as methanol and ethanol; and organic solvents such as acetone and N-methylpyrrolidone. The content of water in the aqueous medium is not particularly limited, but may be 50% by mass or more, 70% by mass or more, 85% by mass or more, or 95% by mass or more, or may be 100% by mass.

[0046] The polymer composition according to this embodiment may contain components other than the abrasive grains, the polymer P, and the aqueous medium. Examples of such components include water-soluble polymers other than the polymer P, pH adjusters, buffers (buffers for stabilizing the pH), and antifoaming agents (e.g., silicone admixtures).

[0047] A water-soluble polymer is defined as a polymer that dissolves at least 0.1 g in 100 g of water (25°C). Examples of water-soluble polymers other than polymer P include polyglycerin; polysaccharides such as alginic acid, pectinic acid, carboxymethylcellulose, agar, curdlan, and pullulan; homopolymers of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid (e.g., polyacrylic acid); ammonium salts or amine salts of the homopolymers; copolymers of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid with monomers such as alkyl acrylate (e.g., methyl acrylate, ethyl acrylate), hydroxyalkyl acrylate (e.g., hydroxyethyl acrylate), alkyl methacrylate (e.g., methyl methacrylate, ethyl methacrylate), hydroxyalkyl methacrylate (e.g., hydroxyethyl methacrylate), vinyl acetate, and vinyl alcohol (e.g., copolymers of acrylic acid and alkyl acrylate); and ammonium salts or amine salts of the copolymers.

[0048] Examples of pH adjusters include organic acids, inorganic acids, organic bases, and inorganic bases. Examples of organic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, lactic acid, maleic acid, phthalic acid, citric acid, and succinic acid. Examples of inorganic acids include nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, and boric acid. Examples of organic bases include triethylamine, pyridine, piperidine, pyrrolidine, imidazole, 2-methylimidazole, and chitosan. Examples of inorganic bases include tetramethylammonium hydroxide (TMAH), ammonia, potassium hydroxide, and sodium hydroxide.

[0049] The buffer may be provided as a buffer solution (a solution containing the buffer), such as an acetate buffer, a phthalate buffer, or the like.

[0050] The pH of the polymer composition according to this embodiment may be 4.0 or more, 4.5 or more, or 5.0 or more, from the viewpoint of easily obtaining good solubility of polymer P in the polymer composition. The pH of the polymer composition according to this embodiment may be less than 7.0, 6.5 or less, 6.0 or less, or 5.5 or less. From these viewpoints, the pH of the polymer composition according to this embodiment may be 4.0 or more and less than 7.0, 4.0 to 6.0, or 5.0 to 6.0.

[0051] <Polishing Liquid Set> The polishing liquid set according to this embodiment comprises the polymer composition according to this embodiment and an abrasive-containing liquid (liquid containing abrasive and an aqueous medium) containing abrasive grains and an aqueous medium. A polishing liquid can be obtained by mixing the polymer composition and the abrasive-containing liquid in the polishing liquid set according to this embodiment. The polishing liquid set according to this embodiment may comprise the polymer composition, the abrasive-containing liquid, and a liquid containing components other than the abrasive grains, polymer P, and aqueous medium (water-soluble polymer, pH adjuster, buffer, antifoaming agent, etc.). At least one selected from the group consisting of the polymer composition and the abrasive-containing liquid may contain the above-mentioned components other than the abrasive grains, polymer P, and aqueous medium (water-soluble polymer, pH adjuster, buffer, antifoaming agent, etc.).

[0052] From the viewpoint of easily obtaining a desired polishing rate for insulating materials (such as silicon oxide), the abrasive grains may contain at least one selected from the group consisting of cerium oxide, silicon oxide (e.g., silica), aluminum oxide (e.g., alumina), zirconium oxide (e.g., zirconia), and yttrium oxide (e.g., yttria), and may also contain cerium oxide. The cerium oxide is CeO ２ (cerium (IV) oxide, ceria), and Ce ２ O ３ (cerium(III) oxide).

[0053] The abrasive-containing liquid may be an abrasive dispersion in which abrasive grains are dispersed in an aqueous medium. The abrasive dispersion may contain a dispersant (abrasive grain dispersant) such as a phosphate compound or a hydrogen phosphate compound. The aqueous medium for the abrasive dispersion may be the same as the aqueous medium for the polymer composition. The aqueous medium for the polymer composition and the aqueous medium for the abrasive dispersion may have the same composition or different compositions.

[0054] <Polishing liquid and manufacturing method thereof> The polishing liquid according to this embodiment contains abrasive grains, a polymer P, and an aqueous medium. In the polishing liquid according to this embodiment, the abrasive grains can be dispersed in the aqueous medium. In the polishing liquid, at least a portion (partial or all) of the polymer P may be dissolved in the aqueous medium. The proportion of the polymer P dissolved in the aqueous medium in the polishing liquid is not particularly limited, but may be 90% by mass or more, 95% by mass or more, or 99% by mass or more.

[0055] The polishing liquid according to this embodiment can be used as a CMP polishing liquid. The polishing liquid according to this embodiment can be used to polish a surface to be polished that includes an insulating material. The polishing liquid according to this embodiment can be used to polish a surface to be polished that includes an insulating material and a stopper material, and can be used to selectively polish the insulating material relative to the stopper material. The polishing liquid according to this embodiment can suitably polish a surface to be polished when the insulating material includes silicon oxide and the stopper material includes silicon nitride.

[0056] The polishing liquid according to this embodiment may be obtained by mixing abrasive grains, polymer P, and an aqueous medium, by mixing abrasive grains and the polymer composition according to this embodiment, or by mixing the polymer composition according to this embodiment with an abrasive-containing liquid containing abrasive grains and an aqueous medium (for example, by mixing the polymer composition in the polishing liquid set according to this embodiment with an abrasive-containing liquid). That is, the method for producing the polishing liquid according to this embodiment may include, as a step for obtaining the polishing liquid, a step for mixing abrasive grains, polymer P, and an aqueous medium, a step for mixing abrasive grains and the polymer composition according to this embodiment, or a step for mixing the polymer composition according to this embodiment with an abrasive-containing liquid containing abrasive grains and an aqueous medium (for example, a step for mixing the polymer composition in the polishing liquid set according to this embodiment with an abrasive-containing liquid).

[0057] The abrasive grains, polymer P, and aqueous medium of the polishing liquid can be the abrasive grains, polymer P, and aqueous medium described above with respect to the polymer composition. For example, from the viewpoint of easily achieving a desired removal rate for insulating materials (such as silicon oxide), the abrasive grains may contain at least one selected from the group consisting of cerium oxide, silicon oxide (e.g., silica), aluminum oxide (e.g., alumina), zirconium oxide (e.g., zirconia), and yttrium oxide (e.g., yttria), and may also contain cerium oxide. The components of the polishing liquid may be the same as or different from the components of the polymer composition and the abrasive-containing liquid.

[0058] The polishing liquid according to this embodiment may use a single type of polymer P, or a combination of two or more types of polymers P. For example, the two or more types of polymers P may be polymers P having different contents of structural units (first structural units, second structural units, etc.), or polymers P having different types of structural units (first structural units, second structural units, etc.).

[0059] The polishing liquid according to this embodiment may contain the above-mentioned components (water-soluble polymer, pH adjuster, buffer, antifoaming agent, etc.) other than the abrasive grains, polymer P, and aqueous medium.

[0060] In the polishing liquid according to this embodiment, the median diameter (D50) of the abrasive grains may be in the following ranges. From the viewpoint of easily improving the removal rate of insulating materials (such as silicon oxide), the median diameter of the abrasive grains may be 1 nm or more, 5 nm or more, 10 nm or more, 20 nm or more, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, 65 nm or more, 70 nm or more, 75 nm or more, or 80 nm or more. From the viewpoint of easily suppressing scratches on the polished surface, the median diameter of the abrasive grains may be 1000 nm or less, 500 nm or less, 300 nm or less, 200 nm or less, 150 nm or less, 120 nm or less, 100 nm or less, 90 nm or less, or 80 nm or less. From these viewpoints, the median diameter of the abrasive grains may be 1 to 1000 nm, 10 to 1000 nm, 10 to 500 nm, 30 to 300 nm, 30 to 200 nm, 50 to 150 nm, or 65 to 100 nm.

[0061] The content of the abrasive grains may be within the following ranges based on the total mass of the polishing liquid. From the viewpoint of easily improving the polishing rate of insulating materials (such as silicon oxide), the content of the abrasive grains may be 0.01 mass% or more, 0.05 mass% or more, 0.1 mass% or more, 0.15 mass% or more, 0.2 mass% or more, 0.25 mass% or more, 0.3 mass% or more, 0.35 mass% or more, 0.4 mass% or more, 0.45 mass% or more, or 0.5 mass% or more. The content of the abrasive grains may be 20 mass% or less, 15 mass% or less, 10 mass% or less, 5 mass% or less, 3 mass% or less, 2 mass% or less, 1 mass% or less, 0.8 mass% or less, 0.6 mass% or less, or 0.5 mass% or less. From these viewpoints, the content of the abrasive grains may be 0.01 to 20 mass%, 0.05 to 10 mass%, or 0.1 to 1 mass%.

[0062] The content of polymer P may be in the following ranges based on the total mass of the polishing liquid, from the viewpoint of easily suppressing excessive dishing or easily suppressing over-polishing of the stopper. The content of polymer P may be 0.01 mass% or more, 0.03 mass% or more, 0.05 mass% or more, 0.08 mass% or more, 0.1 mass% or more, 0.12 mass% or more, 0.14 mass% or more, or 0.15 mass% or more. The content of polymer P may be 10 mass% or less, 8 mass% or less, 5 mass% or less, 3 mass% or less, 2 mass% or less, 1 mass% or less, 0.8 mass% or less, 0.5 mass% or less, 0.3 mass% or less, 0.2 mass% or less, or 0.15 mass% or less. From these viewpoints, the content of polymer P may be 0.01 to 10 mass%, 0.05 to 1 mass%, or 0.1 to 0.5 mass%.

[0063] The content of polymer P may be in the following ranges per 100 parts by mass of abrasive grains, from the viewpoint of easily suppressing excessive dishing or easily suppressing over-polishing of the stopper. The content of polymer P may be 1 part by mass or more, 5 parts by mass or more, 6 parts by mass or more, more than 6 parts by mass, 10 parts by mass or more, 15 parts by mass or more, 20 parts by mass or more, 25 parts by mass or more, or 30 parts by mass or more. The content of polymer P may be 100 parts by mass or less, 80 parts by mass or less, 60 parts by mass or less, 55 parts by mass or less, 50 parts by mass or less, 45 parts by mass or less, 40 parts by mass or less, 35 parts by mass or less, or 30 parts by mass or less. From these viewpoints, the content of polymer P may be 1 to 100 parts by mass, 1 to 60 parts by mass, or 10 to 50 parts by mass.

[0064] The pH of the polishing liquid according to this embodiment may be in the following ranges, from the viewpoint of easily suppressing excessive dishing or easily suppressing over-polishing of the stopper. The pH of the polishing liquid may be 3.0 or more, 3.5 or more, 4.0 or more, 4.5 or more, 5.0 or more, 5.4 or more, or 5.5 or more. The pH of the polishing liquid may be 7.0 or less, less than 7.0, 6.5 or less, 6.0 or less, or 5.5 or less. From these viewpoints, the pH of the polishing liquid may be 3.0 to 7.0, 4.0 to 6.5, or 5.0 to 6.0.

[0065] <Polishing Method> The polishing method according to this embodiment includes a polishing step of polishing a surface to be polished using the polishing liquid according to this embodiment. The polishing liquid used in the polishing step may be obtained by mixing abrasive grains and a polymer P, may be obtained by mixing abrasive grains and the polymer composition according to this embodiment, or may be obtained by mixing the polymer composition according to this embodiment with an abrasive-containing liquid containing abrasive grains and an aqueous medium (for example, it may be obtained by mixing the polymer composition in the polishing liquid set according to this embodiment with the abrasive-containing liquid). The polishing method according to this embodiment is, for example, a method for polishing a substrate having a surface to be polished.

[0066] The surface to be polished may include an insulating material, and may include silicon oxide. The surface to be polished may include an insulating material and a stopper material (silicon nitride, polysilicon, etc.), and may include, for example, silicon oxide and silicon nitride. The polishing method according to this embodiment may be a method for polishing a substrate having a surface to be polished that includes an insulating material (silicon oxide, etc.) and a stopper material (silicon nitride, polysilicon, etc.). The substrate may have, for example, an insulating member that includes an insulating material and a stopper that includes a stopper material.

[0067] The polishing method according to this embodiment is a method for polishing a surface to be polished that includes an insulating material (such as silicon oxide) and a stopper material (such as silicon nitride or polysilicon), and may include a polishing step of selectively polishing the insulating material relative to the stopper material using the polishing liquid according to this embodiment, or a polishing step of selectively polishing silicon oxide relative to silicon nitride using the polishing liquid according to this embodiment. "Selectively polishing material A relative to material B" means that, under the same polishing conditions, the polishing rate of material A is higher than the polishing rate of material B. When selectively polishing silicon oxide relative to silicon nitride, the polishing selectivity of silicon oxide relative to silicon nitride may be 10 or more, 20 or more, 30 or more, or 35 or more.

[0068] The substrate to be polished may be, for example, a substrate used in the manufacture of semiconductor components (e.g., a semiconductor substrate on which an STI pattern, a gate pattern, a wiring pattern, etc., is formed) on which a polished member is formed. Examples of materials to be polished that constitute the polished member include insulating materials (excluding stopper materials) such as silicon oxide; and stopper materials such as silicon nitride and polysilicon. The polished material may be a single material or multiple materials. When multiple materials are exposed on the polished surface, they can be considered as the polished material. The polished member may be in the form of a film (polished film). An insulating member containing an insulating material may be in the form of a film (insulating film: silicon oxide film, etc.). A stopper containing a stopper material may be in the form of a film (stopper film: silicon nitride film, polysilicon film, etc.).

[0069] By using the polishing liquid according to this embodiment to polish a polished member (e.g., an insulating film such as a silicon oxide film) formed on a substrate and removing excess portions, it is possible to eliminate unevenness on the surface of the polished member and obtain a smooth surface over the entire polished surface.

[0070] The polishing method according to this embodiment can polish an insulating member in a base (e.g., a base having an insulating member, a stopper disposed below the insulating member, and a semiconductor substrate disposed below the stopper) that includes a substrate having a concave-convex pattern, a stopper disposed on the convex portions of the substrate, and an insulating member (e.g., a silicon oxide film containing at least silicon oxide on its surface) disposed on the substrate and the stopper so as to fill the concave portions of the concave-convex pattern. In such a base, polishing can be stopped when the stopper is exposed to prevent excessive polishing of the insulating member, thereby improving the flatness of the insulating member after polishing. The stopper material constituting the stopper has a lower polishing rate than the insulating material, and may be silicon nitride, polysilicon, or the like.

[0071] The polishing liquid and polishing method according to this embodiment can also be used to polish pre-metal insulating films, which may be made of silicon oxide, phosphorus silicate glass, boron-phosphorus silicate glass, silicon oxyfluoride, amorphous carbon fluoride, or the like.

[0072] The polishing liquid and polishing method according to this embodiment can be applied to materials other than insulating materials such as silicon oxide, etc. Examples of such materials include high-dielectric-constant materials such as Hf-based, Ti-based, and Ta-based oxides; semiconductor materials such as silicon, amorphous silicon, SiC, SiGe, Ge, GaN, GaP, GaAs, and organic semiconductors; phase-change materials such as GeSbTe; inorganic conductive materials such as ITO; and polymer resin materials such as polyimide, polybenzoxazole, acrylic, epoxy, and phenolic.

[0073] The polishing liquid and polishing method according to this embodiment can be applied not only to film-like objects to be polished, but also to various substrates made of glass, silicon, SiC, SiGe, Ge, GaN, GaP, GaAs, sapphire, plastic, etc.

[0074] The polishing liquid and polishing method according to this embodiment can be used not only in the manufacture of semiconductor parts, but also in the manufacture of image display devices such as TFTs and organic ELs; optical components such as photomasks, lenses, prisms, optical fibers, and single-crystal scintillators; optical elements such as optical switching elements and optical waveguides; light-emitting elements such as solid-state lasers and blue laser LEDs; and magnetic storage devices such as magnetic disks and magnetic heads.

[0075] <Component Manufacturing Method, etc.> The component manufacturing method according to this embodiment includes a component fabrication step in which a component is obtained using a polished member polished by the polishing method according to this embodiment. The component according to this embodiment is a component obtained by the component manufacturing method according to this embodiment. The component according to this embodiment is not particularly limited and may be an electronic component (e.g., a semiconductor component such as a semiconductor package), a wafer (e.g., a semiconductor wafer), or a chip (e.g., a semiconductor chip). As one aspect of the component manufacturing method according to this embodiment, an electronic component is obtained using a polished member polished by the polishing method according to this embodiment. As one aspect of the component manufacturing method according to this embodiment, a semiconductor component (e.g., a semiconductor package) is obtained using a polished member polished by the polishing method according to this embodiment. The component manufacturing method according to this embodiment may include a polishing step in which a polished member is polished by the polishing method according to this embodiment before the component fabrication step.

[0076] The component manufacturing method according to this embodiment may include, as one aspect of the component manufacturing process, a singulation process for singulating a polished member polished by the polishing method according to this embodiment. The singulation process may be, for example, a process for dicing a wafer (e.g., a semiconductor wafer) polished by the polishing method according to this embodiment to obtain chips (e.g., semiconductor chips). As one aspect of the component manufacturing method according to this embodiment, the electronic component manufacturing method according to this embodiment may include a process for singulating a polished member polished by the polishing method according to this embodiment to obtain electronic components (e.g., semiconductor components). As one aspect of the component manufacturing method according to this embodiment, the semiconductor component manufacturing method according to this embodiment may include a process for singulating a polished member polished by the polishing method according to this embodiment to obtain semiconductor components (e.g., semiconductor packages).

[0077] The component manufacturing method according to this embodiment may include, as one aspect of the component manufacturing process, a connecting process for connecting (e.g., electrically connecting) a polished member polished by the polishing method according to this embodiment to another connected object. The connected object to be connected to the polished member polished by the polishing method according to this embodiment is not particularly limited and may be the polished member polished by the polishing method according to this embodiment, or may be a connected object different from the polished member polished by the polishing method according to this embodiment. In the connecting process, the polished member and the connected object may be directly connected (connected in a state where the polished member and the connected object are in contact), or the polished member and the connected object may be connected via another member (such as a conductive member). The connecting process may be performed before the singulation process, after the singulation process, or before or after the singulation process.

[0078] The connecting step may be a step of connecting a polished surface of a polished member polished by the polishing method according to this embodiment to a connected body, or a step of connecting a connecting surface of a polished member polished by the polishing method according to this embodiment to a connecting surface of a connected body. The connecting surface of the polished member may be a polished surface polished by the polishing method according to this embodiment. A connected body including a polished member and a connected body can be obtained by the connecting step. In the connecting step, if the connecting surface of the polished member has a metal portion, the connected body may be brought into contact with the metal portion. In the connecting step, if the connecting surface of the polished member has a metal portion and the connecting surface of the connected body has a metal portion, the metal portions may be brought into contact with each other. The metal portion may include, for example, copper.

[0079] The device according to this embodiment (for example, an electronic device such as a semiconductor device) includes at least one member selected from the group consisting of a polished member polished by the polishing method according to this embodiment and a part according to this embodiment.

[0080] Hereinafter, the present disclosure will be specifically described based on examples, but the present disclosure is not limited to these examples.

[0081] <Preparation of Polymer Composition> In each Example and Comparative Example, a polymer shown in Table 1, a pH adjuster, and ion-exchanged water were mixed to obtain a polymer composition having a polymer content of 3.0% by mass and a pH (25°C) of 5.2. A 10% by mass aqueous solution of acetic acid was used as the pH adjuster in all Examples and Comparative Examples. The pH of the polymer composition was measured according to the measurement method described in the definition of pH above. The types of structural units contained in the polymers of each Example and Comparative Example are as shown in Table 1. In Table 1, St represents styrene, MAa represents methacrylic acid, and Aa represents acrylic acid. The polymers in Table 1 have each structural unit in the monomer ratio shown in Table 1.

[0082] <Weight-Average Molecular Weight of Polymer> Gel permeation chromatography (GPC) was performed under the following conditions, and the weight-average molecular weight (Mw) of the polymer was measured in terms of pullulan. The measurement results are shown in Table 1. Instrument (detector): Shodex GPC-101, manufactured by Showa Denko K.K. Column: Shodex SB-807, 806M, 803, manufactured by Showa Denko K.K. Eluent: 0.05 M aqueous disodium hydrogen phosphate Measurement temperature: 40°C Flow rate: 0.8 mL / min Measurement time: 60 minutes Sample: A sample prepared by adjusting the polymer content in a polymer composition with a solution of the same composition as the eluent so that the polymer content was 0.1 mass %, and filtering the resultant through a 0.45 μm membrane filter Injection volume: 100 μL Standard substance: Shodex STANDARD P-82, manufactured by Showa Denko K.K.

[0083] <Total amount of carboxyl groups and carboxylate salt groups in polymer> The total amount of carboxyl groups and carboxylate salt groups in the polymer, C [mol / g], was calculated using the following formula. The results are shown in Table 1. C=Σ{N ｉ × (R ｉ / 100)} / Σ{M ｉ × (R ｉ / 100) M ｉN: Molecular weight [g / mol] of each monomer used to obtain a polymer (however, in cases where the carboxyl group forms a salt (for example, when a carboxylate salt is used as a monomer, or when a salt is formed by ion exchange after polymerization of a carboxylic acid), the molecular weight is the molecular weight in which these structures are replaced with a carboxyl group (COOH)). ｉ : the valence of the carboxyl group and carboxylate group of each monomer (for example, N in the case of styrene) ｉ = 0) R ｉ : Proportion of each monomer in the total amount of monomers used to obtain a polymer [mol %]

[0084] <Storage Stability of Polymer Composition> (Visual Observation of Presence or Absence of Sediment) First, 45 g of the above-described polymer composition was sealed in a 50 mL centrifuge tube, and the centrifuge tube was allowed to stand at 60°C for 7 days (168 hours). Thereafter, the centrifuge tube was cooled to 25°C and centrifuged for 40 minutes at a centrifugal acceleration of 9700 G (9700 times the acceleration of gravity) using a centrifuge (KUBOTA, High-Speed, Large-Capacity Refrigerated Centrifuge 7000). Thereafter, the presence or absence of sediment formed in the centrifuge tube was visually observed and evaluated according to the following criteria. The polymer composition was maintained at 25°C from centrifugation to observation and during observation. The results are shown in Table 1. A: No sediment or turbidity was observed. B: A small amount of sediment was observed, but it redissolved upon shaking. C: More sediment than B was observed, but it redissolved upon shaking. D: Sediment was observed, but it did not redissolve even when shaken.

[0085] (Measurement of transmittance) The transmittance of the polymer composition (supernatant) after the above-mentioned centrifugation was measured. Specifically, the transmittance of light with a wavelength of 700 nm was measured using a spectrophotometer (manufactured by Shimadzu Corporation, product name: UV-1900) and a quartz cell with an optical path length of 10 mm. The polymer composition was kept at 25°C from centrifugation to measurement and during measurement. The results are shown in Table 1.

[0086] <Preparation of Polishing Liquid> In Examples 1 to 5 and Comparative Examples 1 to 3, 100 parts by mass of a polishing liquid (CMP polishing liquid) having a pH of 5.5 was prepared by mixing 0.5 parts by mass of abrasive grains (ceria particles), 0.15 parts by mass of the polymer shown in Table 1, 0.06 parts by mass of acetic acid, 0.003 parts by mass of an antifoaming agent (a silicone admixture, manufactured by Momentive Performance Materials Japan, LLC, product name: TSA780), and ion-exchanged water. The polymer shown in Table 1 was supplied using the polymer composition described above. The pH of the polishing liquid was measured according to the measurement method described in the definition of pH above. The median diameter (D50) of the abrasive grains was measured according to the measurement method described in the definition of median diameter above. As a result, the median diameter in Examples 1 to 5 and Comparative Examples 1 to 3 was 80 nm.

[0087] <Polishing of Substrate to be Polished> Using the polishing solutions of Examples 1 to 5 and Comparative Examples 1 to 3, substrates to be polished were polished under the following polishing conditions.

[0088] {Polishing conditions} Polishing apparatus: Reflexion LK (manufactured by APPLIED MATERIALS) Flow rate of polishing liquid: 250 mL / min Substrate to be polished: Wafer with the following pattern Polishing pad: Polyurethane foam resin having closed cells (manufactured by Dow Chemical Japan, model number IC1010) Polishing pressure: 3.0 psi (20.6 kPa) Rotation speeds of substrate and polishing platen: Substrate / polishing platen = 93 / 87 rpm Polishing time: From the time the stopper was exposed until 15 seconds Drying of wafer: After polishing, the wafer was dried with a spin dryer.

[0089] {Patterned Wafer} A patterned wafer on which a simulated pattern is formed is formed by laminating a silicon nitride film (SiN film) as a stopper on a silicon substrate, forming trenches in an exposure and development process, and then depositing a silicon oxide film (SiO ) as an insulating film on the silicon substrate and the stopper so as to fill the stopper and the trench. ２ The silicon oxide film was formed by a high density plasma (HDP) method.

[0090] The above-mentioned pattern wafer had "a portion where the line (L) as a convex portion / the space (S) as a concave portion were arranged at a pitch of 100 μm and the convex pattern density was 50%" (a portion where L / S=50 / 50 μm) and "a portion where the L / S was arranged at a pitch of 100 μm and the convex pattern density was 20%" (a portion where L / S=20 / 80 μm).

[0091] L / S is a simulated pattern in which active portions masked with a silicon nitride film, which are convex portions, and trench portions in which grooves, which are concave portions, are arranged alternately. For example, "L / S at a 100 μm pitch" means that the total width of the active portions (line portions) and trench portions (space portions) is 100 μm. For example, "L / S at a 100 μm pitch, with a convex portion pattern density of 50%" means a pattern in which convex portions with a width of 50 μm and concave portions with a width of 50 μm are arranged alternately.

[0092] In the patterned wafer, the thickness of the silicon oxide film was 420 nm both on the silicon substrate in the recessed portions and on the silicon nitride film in the protruding portions. Specifically, the thickness of the silicon nitride film on the silicon substrate was 120 nm, the thickness of the silicon oxide film in the protruding portions was 420 nm, and the thickness of the silicon oxide film in the recessed portions was 420 nm. The depth of the recessed portions of the silicon oxide film was 300 nm (trench depth 180 nm + thickness of the silicon nitride film 120 nm).

[0093] <Evaluation of Polishing Characteristics> The substrate to be polished (patterned wafer) described above was polished under the polishing conditions described above to expose the stopper, and then the stopper was further polished (over-polished) for 15 seconds to remove the stopper. At this point, the polished amount (SiN loss) and remaining step amount (Dishing) of the stopper in the "L / S=50 / 50 μm portion" and the "L / S=20 / 80 μm portion" were calculated using the following procedure.

[0094] (Polished Amount of Stopper) The polished amount of stopper (SiN loss) was calculated as the difference between the initial film thickness of the stopper on the convex portion and the remaining film thickness of the stopper on the convex portion after polishing, as shown in the following formula. The film thickness of the stopper before and after polishing was calculated using an optical interference film thickness measuring device (manufactured by Nova, product name: Nova i500). The results are shown in Table 1. (Polished amount of stopper [nm]) = (Initial film thickness of stopper on the convex portion [nm]) - (Remaining film thickness of stopper on the convex portion after polishing [nm])

[0095] (Remaining step amount) The "L / S = 50 / 50 μm portion" and the "L / S = 20 / 80 μm portion" of the polished substrate were scanned with an automatic atomic force step profiler (manufactured by Bruker, product name: InSight CAP) to measure the height difference between the convex portion and the concave portion, thereby obtaining the remaining step amount (dishing). The results are shown in Table 1.

[0096]

Claims

1. A polymer for a polishing liquid, the polymer having a first structural unit derived from at least one styrene compound selected from the group consisting of styrene and styrene derivatives, and a second structural unit derived from at least one methacrylic acid compound selected from the group consisting of methacrylic acid and salts thereof, the content of the first structural unit being more than 0 mol% and not more than 38 mol%.

2. The polymer of claim 1, wherein the first structural unit comprises a structural unit derived from styrene.

3. The polymer according to claim 1 or 2, wherein the content of the second structural unit is 60 to 90 mol %.

4. The total amount of carboxyl groups and carboxylate groups is 6.7 x 10 －３ 4. The polymer according to claim 1, wherein the converted total amount is calculated by replacing carboxylate groups in the polymer with carboxy groups.

5. The polymer according to any one of claims 1 to 4, having a weight average molecular weight of 3,000 to 500,000.

6. A polymer composition comprising the polymer according to any one of claims 1 to 5 and an aqueous medium.

7. A polishing liquid set comprising the polymer composition according to claim 6 and a liquid containing abrasive grains and an aqueous medium.

8. The polishing liquid set according to claim 7, wherein the abrasive grains contain at least one type selected from the group consisting of cerium oxide, silicon oxide, aluminum oxide, zirconium oxide and yttrium oxide.

9. A polishing liquid comprising an abrasive grain, the polymer according to any one of claims 1 to 5, and an aqueous medium.

10. The polishing liquid according to claim 9, wherein the abrasive grains contain at least one selected from the group consisting of cerium oxide, silicon oxide, aluminum oxide, zirconium oxide and yttrium oxide.

11. A method for producing a polishing liquid, comprising the step of mixing the polymer composition according to claim 6 with a liquid containing abrasive grains and an aqueous medium.

12. A polishing method comprising the step of polishing a surface to be polished with the polishing liquid according to claim 9.

Images