Polishing composition and polishing method

Abstract

To provide means that enables reduction of defects on the surface of a resin material after polishing, while sustaining a high polishing removal rate, during polishing of a polishing target including the resin material.SOLUTION: A polishing composition contains water and alumina particles, wherein, for the alumina particles, D2 is a particle diameter at which the cumulative frequency from the fine particle diameter side in a volume-based particle size distribution reaches 2%, D50 is a particle diameter at which the cumulative frequency from the fine particle diameter side in the volume-based particle size distribution reaches 50%, D98 is a particle diameter at which the cumulative frequency from the fine particle diameter side in the volume-based particle size distribution reaches 98%, SA is a BET specific surface area, and SA' is a theoretical specific surface area calculated from D50, an irregularity degree N represented by formula (1) satisfies the relationship of formula (2), and a distortion degree S represented by formula (3) satisfies the relationship of formula (4).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polishing composition and a polishing method. [Background technology]

[0002] In the semiconductor industry, planarization techniques are commonly used to increase the flatness of semiconductor substrate (e.g., wafer) surfaces. Chemical mechanical polishing (CMP) is one of the commonly used planarization techniques. Chemical mechanical polishing is a method of planarizing the surface of an object to be polished, such as a semiconductor substrate, using a polishing composition containing abrasive grains such as silica, alumina, or ceria, a corrosion inhibitor, a surfactant, etc.

[0003] Furthermore, substrates containing resin materials (sometimes referred to herein as "resin-containing substrates") have become more common, and the need for polishing compositions that can be used to polish resin-containing substrates has also gradually increased.

[0004] For example, Patent Document 1 discloses a chemical mechanical polishing composition containing alumina, a complexing agent, and an oxidizing agent. The chemical mechanical polishing composition of Patent Document 1 can be used to chemically polish a resin layer and a conductor layer containing a metal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-268666 Summary of the Invention [Problem to be solved by the invention]

[0006] However, there has not been a polishing composition that can polish a substrate containing a resin material at high speed while reducing defects on the surface of the resin material after polishing.

[0007] Therefore, an object of the present invention is to provide a means for reducing defects on the surface of a resin material after polishing while maintaining a high polishing removal rate when polishing an object containing a resin material. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above problems, and as a result have found that the above problems can be solved by the following means, thereby completing the present invention.

[0009] That is, the above-mentioned problems of the present invention can be solved by the following means.

[0010] A polishing composition used for polishing an object to be polished containing a resin material, comprising water and alumina particles, wherein the particle diameter of the alumina particles at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution is 2% is defined as D2, and the particle diameter at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution is 50% is defined as D 50 The particle size at which the cumulative frequency from the small particle size side in the volume-based particle size distribution is 98% is defined as D 98 The BET specific surface area is SA, and the D 50 When SA' is the theoretical specific surface area calculated from the above formula, the irregularity N expressed by the following formula (1) satisfies the relationship of the following formula (2), and the distortion S expressed by the following formula (3) satisfies the relationship of the following formula (4).

[0011]

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[0012] According to the present invention, it is possible to provide a means for reducing defects on the surface of a resin material after polishing while maintaining a high polishing removal rate when polishing an object containing a resin material. DETAILED DESCRIPTION OF THE INVENTION

[0013] The following describes embodiments of the present invention. The embodiments shown here are provided as examples to embody the technical concept of the present invention and are not intended to limit the present invention. Therefore, all other possible embodiments, methods of use, and operational techniques that can be conceived by those skilled in the art without departing from the spirit of the present invention are included in the scope and spirit of the present invention, as well as in the scope of the inventions described in the claims and their equivalents. The embodiments described in this specification can be combined in any manner to create other embodiments.

[0014] In this specification, unless otherwise specified, operations and measurements of physical properties are performed at room temperature (20° C. to 25° C.) and a relative humidity of 40% RH to 50% RH.

[0015] The first embodiment of the present invention is a polishing composition used for polishing an object to be polished containing a resin material, comprising alumina particles and water, wherein the particle diameter of the alumina particles at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution is 2% is defined as D2, and the particle diameter at which the cumulative frequency from the small particle diameter side in the volume-based particle size distribution is 50% is defined as D 50 The particle size at which the cumulative frequency from the small particle size side in the volume-based particle size distribution is 98% is defined as D 98 The BET specific surface area is SA, and the D 50 When SA' is the theoretical specific surface area calculated from the above, the irregularity N expressed by the following formula (1) satisfies the relationship in the following formula (2), and the distortion S expressed by the following formula (3) satisfies the relationship in the following formula (4).

[0016]

number

[0017] The polishing composition of this embodiment having the above-described configuration can reduce defects on the surface of the resin material after polishing while maintaining a high polishing removal rate when polishing an object containing a resin material.

[0018] The present invention will be described in detail below. In this specification, the term "polishing removal rate" has the same meaning as the terms "polishing rate" and "polishing rate."

[0019] [Polished object] The polishing composition according to some embodiments of the present invention is particularly suitable for polishing a substrate having a patterned structure formed from a material containing a resin material, and the technical effects of the present invention are fully exhibited when polishing such a substrate.

[0020] The resin material contained in the object to be polished is not particularly limited, but examples include polyethylene terephthalate (PET), polybenzoxazole (PBO), polybutylene terephthalate (PBT), polyimide (PI), polyamide (PA), epoxy resin, urethane acrylate resin, unsaturated polyester resin, phenolic resin, polynorbornene resin, polyacetal (POM), polycarbonate (PC), modified polyphenylene ether (m-PPE), ultra-high molecular weight polyethylene (UHMWPE), syndiotactic polystyrene (SPS), amorphous polyarylate (PAR), polysulfone (PSF), polyethersulfone (PES), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyetherimide (PEI), benzocyclobutene (BCB), fluororesin, and liquid crystal polymer (LCP). Among these, polyimide (PI), epoxy resin, urethane acrylate resin, or benzocyclobutene (BCB) is preferred. The above resin materials can be used singly or in combination of two or more. According to some embodiments of the present invention, the resin material contains polyimide (PI). By containing polyimide (PI), the desired effects of the present invention can be efficiently achieved. By adopting such an embodiment, the desired effects of the present invention can be efficiently achieved.

[0021] In addition to the resin material, the polishing target preferably further contains a metal material. The type of metal material is not particularly limited, but examples include magnesium (Mg), aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium (Zr), gold (Au), silver (Ag), platinum (Pt), iridium (Ir), bismuth (Bi), niobium (Nb), molybdenum (Mo), tin (Sn), tungsten (W), and lead (Pb). Among these, transition metals (especially elements of Groups 6, 9, and 11 of the periodic table), elements of Group 13, or elements of Group 14 of the periodic table are preferred, and elements of Group 11 or 14 of the periodic table are even more preferred. The element of Group 11 of the periodic table is more preferably copper (Cu), and the element of Group 14 of the periodic table is more preferably tin (Sn). The metal material may be any of various metal elements, or an alloy of these elements with one or more other elements. The metal materials may be used singly or in combination of two or more.

[0022] [Polishing composition] [Alumina particles] The polishing composition according to this embodiment contains alumina particles as abrasive grains. The abrasive grains mechanically polish the object to be polished, thereby improving the polishing removal rate. The alumina particles have sufficient hardness, and are therefore particularly effective in improving the polishing removal rate of resin materials.

[0023] The alumina particles have an irregularity N, expressed by the above formula (1), that satisfies the relationship of the above formula (2). The irregularity N, expressed by the above formula (1), is a parameter that indicates the degree of irregularity of the particle's outer shape relative to a perfect sphere of the same particle diameter, and the larger the irregularity N is above 1, the greater the degree of irregularity of the particle shape. An irregularity N of 1 indicates that the particle is a perfect sphere. The alumina particles according to this embodiment have an irregularity N in the range of 2 or more and 6 or less, and therefore have a large degree of irregularity of the particle shape.

[0024] Further, the alumina particles satisfy the relationship of the distortion degree S represented by the above formula (3) with respect to the relationship of the above formula (4). The distortion degree S represented by the above formula (3) is a parameter representing the symmetry (skewness) of the particle size distribution in the alumina particles. Here, the particle size distribution refers to a graph in which the particle size (μm) represented by the common logarithm of the base 10 is taken on the X-axis and the volume frequency (%) is taken on the Y-axis. The fact that the distortion degree S is less than 1 (S < 1) means that the particle size distribution of the alumina particles has a bias toward the large particle size side, that is, there are relatively many alumina particles with a large particle size. On the other hand, the fact that the distortion degree S exceeds 1 (1 < S) means that the particle size distribution of the alumina particles has a bias toward the small particle size side, that is, there are relatively many alumina particles with a small particle size. The fact that the distortion degree S is 1 (S = 1) indicates that the particle size distribution of the alumina particles is symmetric, that is, the particle size distribution of the alumina particles is a log-normal distribution. Since the distortion degree S of the alumina particles according to the present embodiment is in the range of 0.50 or more and 0.80 or less, the particle size distribution has a bias toward the large particle size side (there are relatively many large particle size particles).

[0025] Generally, it is known that abrasive grains with a relatively large size have a high polishing removal rate, and it is also known that the polishing removal rate increases as the irregularity and aspect ratio of the shape of the abrasive grains increase. On the other hand, abrasive grains with a relatively large size, or abrasive grains with a high irregularity and aspect ratio of the shape, increase defects such as scratches on the surface of the polished object after polishing. In contrast, although abrasive grains with a relatively small size have a slower polishing removal rate, they tend to improve defects such as scratches on the surface of the polished object after polishing. Also, it is known that spherical particles have a relatively low polishing removal rate compared to irregular particles, but reduce defects such as scratches on the surface of the polished object after polishing. Thus, there is a trade-off relationship between the improvement of the polishing removal rate and the occurrence of defects such as scratches. However, as a result of repeated research by the present inventors, in the polishing of a polishing object containing a resin material, a polishing composition containing alumina particles in which the irregularity degree N represented by the above formula (1) satisfies the relationship of the above formula (2) and the distortion degree S represented by the above formula (3) satisfies the relationship of the above formula (4) can maintain a high polishing removal rate while reducing defects on the surface of the resin material after polishing.

[0026] <Deformity degree N> If the irregularity N of the alumina particles is less than 2, the polishing removal rate of the resin material (object to be polished) decreases. If the irregularity N of the alumina particles is more than 6, scratches on the polished surface of the resin material (object to be polished) become worse. The irregularity N of the alumina particles is preferably 2.1 or more and 5.0 or less, and more preferably 2.2 or more and 4.0 or less.

[0027] The BET specific surface area SA of the alumina particles used in calculating the irregularity N is the specific surface area measured in accordance with JIS Z8830: 2013. More specifically, it can be measured by the method described in the examples.

[0028] The theoretical specific surface area SA' of the alumina particles is calculated by the D 50 The value is calculated using the following formula (5).

[0029]

number

[0030] In the above formula (5), ρ is the density of the alumina particles, and is 3.95 g / cm 3 Use the value of

[0031] <Distortion S> If the strain rate S of the alumina particles is less than 0.50, scratches on the surface of the polished resin material (object to be polished) will worsen. If the strain rate S of the alumina particles is more than 0.80, the polishing removal rate of the resin material (object to be polished) will decrease. The strain rate S of the alumina particles is preferably 0.55 or more and 0.78 or less, and more preferably 0.60 or more and 0.75 or less.

[0032] D2 and D of alumina particles used to calculate the strain S 50 , and D 98can be determined by dynamic light scattering, laser diffraction, laser scattering, or pore electrical resistance, etc. In this specification, the values ​​used are those determined from the particle diameters at which the cumulative frequency from the small particle diameter side is 2%, 50%, and 98% in the volume-based particle size distribution measured using a laser diffraction particle size distribution analyzer. More specifically, it can be measured by the method described in the Examples.

[0033] The shape of the alumina particles is not particularly limited as long as the irregularity N and the distortion S satisfy the relationship of the above formulas (2) and (4). Examples of the shape of the alumina particles include polygonal prisms such as triangular prisms and quadrangular prisms, cylinders, bale-shaped cylinders in which the center is bulging more than the ends, doughnut-shaped discs with a central hole, plates, cocoon-shaped shapes with a central constriction, associative spheres in which multiple particles are integrated, confetti-shaped shapes with multiple protrusions on the surface, rugby ball-shaped shapes, cones, truncated cones, pyramids, truncated pyramids, hemispheres, needles, and irregular shapes.

[0034] As long as the irregularity N and the distortion S satisfy the relationships of the above formulas (2) and (4), the D of the alumina particles 50 is not particularly limited. For example, the D of alumina particles 50 is preferably 2.0 μm or less, more preferably 1.5 μm or less, even more preferably 1.0 μm or less, particularly preferably 0.8 μm or less, and most preferably 0.4 μm or less. 50 is preferably 0.01 μm or more, more preferably 0.02 μm or more, even more preferably 0.05 μm or more, particularly preferably 0.1 μm or more, and most preferably 0.2 μm or more. 50 When the D of the alumina particles is within the above range, it is possible to achieve a good balance between improving the polishing removal rate of the resin material and reducing scratches on the surface of the resin material after polishing. 50A preferred example of the thickness is preferably 0.01 μm or more and 2.0 μm or less, more preferably 0.02 μm or more and 1.5 μm or less, even more preferably 0.05 μm or more and 1.0 μm or less, particularly preferably 0.1 μm or more and 0.8 μm or less, and most preferably 0.2 μm or more and 0.4 μm or less.

[0035] <αization rate> The alumina particles preferably contain an α-phase, which is a preferred crystalline structure for polishing abrasive grains, or a transitional crystalline phase, such as a θ-phase, a δ-phase, or a γ-phase, which is in the process of becoming an α-phase. More preferably, the alumina particles contain an α-phase or a θ-phase, and even more preferably, they contain an α-phase. It is believed that there is an optimal range for the α-phase depending on the degree of α-phase formation.

[0036] Generally, the α-phase crystal structure is considered to be the hardest, but if sintered sufficiently at high temperatures to convert to the α-phase, the particle shape will become rounded and the polishing performance will likely decrease. The α-phase ratio is a useful value for expressing the degree of α-phase contained in alumina particles. The preferred lower limit of the α-phase ratio is 50% or more. The lower limit of the α-phase ratio is more preferably 60% or more, even more preferably 70% or more, even more preferably 80% or more, and particularly preferably 90% or more. The preferred upper limit of the α-phase ratio is 100% or less. The upper limit of the α-phase ratio is more preferably 98% or less. That is, the α-phase ratio of alumina particles is preferably 50% or more and 100% or less, more preferably 60% or more and 98% or less, and even more preferably 80% or more and 98% or less.

[0037] By setting the alpha conversion rate within the above preferred range, it is expected that the polishing power will be improved, i.e., the polishing removal rate of the resin material will be further improved. The alpha conversion rate of the alumina particles can be calculated from the integrated intensity ratio of the peak at 2θ=43°±2° corresponding to the (113) plane obtained by X-ray diffraction measurement using Cu-Kα radiation for the reference material and the measurement sample. More specific methods are described in the examples.

[0038] <Concentration (content)> The concentration (content) of alumina particles in the polishing composition is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, particularly preferably 1% by mass or more, and particularly preferably 1.5% by mass or more, relative to the total mass of the polishing composition. As the concentration of alumina particles increases, the polishing removal rate improves. Furthermore, the concentration (content) of alumina particles is preferably 25% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, even more preferably less than 9% by mass, and particularly preferably 8% by mass or less, relative to the total mass of the polishing composition. Within the above range, the polishing removal rate of the resin material can be further improved. In addition, there is also the effect of further reducing the occurrence of defects such as scratches on the surface of the resin material after polishing. A preferred example of the concentration (content) of alumina particles is 0.01 mass% or more and 25 mass% or less, more preferably 0.1 mass% or more and 15 mass% or less, even more preferably 0.5 mass% or more and 10 mass% or less, still more preferably 1 mass% or more and less than 9 mass%, and particularly preferably 1.5 mass% or more and 8 mass% or less, relative to the total mass of the polishing composition.

[0039] The method for producing alumina particles having an irregularity N and a distortion S satisfying the above formulas (2) and (4) is not particularly limited. One example is a method in which a starting material such as an aluminum oxide precursor powder is fired to produce a powder, and the powder is then appropriately crushed and / or classified.

[0040] The aluminum oxide precursor powder can be aluminum hydroxide powder or aluminum oxide powder containing a transitional aluminum oxide phase. The aluminum hydroxide powder can be gibbsite, boehmite, pseudoboehmite, diaspore, or any combination thereof. The aluminum oxide precursor powder can include gamma (γ), eta (η), theta (θ), chi (χ), kappa (κ), and / or delta (δ) phase aluminum oxide.

[0041] The aluminum oxide precursor powder can be calcined to form aluminum oxide (alumina). The calcination method is not particularly limited, but examples include methods using a rotary kiln, tunnel kiln, electric furnace, muffle furnace, elevator kiln, or pusher kiln. The calcination temperature can be 700°C or higher and 1600°C or lower, and the calcination time can be 1 hour or higher and 48 hours or lower. This allows for the production of α-alumina with a suitable degree of alpha conversion. The higher the calcination temperature, the smaller the specific surface area tends to be.

[0042] The calcined alumina powder can be crushed and classified to obtain alumina having a desired particle size distribution. Crushing and classification can be carried out by a wet process or a dry process.

[0043] Examples of the pulverization method include a method using a pulverizer. Examples of the pulverizer that can be used include known devices such as a ball mill, bead mill, planetary mill, vibration mill, colloid mill, conical mill, disk mill, edge mill, flour mill, hammer mill, mortar, pellet mill, VSI mill, Willy mill, roller mill, jet mill, homomixer, high-pressure homogenizer, and ultrasonic device. In each device, alumina having a desired particle size distribution can be obtained by changing the pulverization conditions, such as the pulverization time.

[0044] Examples of classification methods include filtering, sieving, air classification, elutriation classification, weight classification, inertial classification, and centrifugal classification. Examples of filtering include coarse filtration, microfiltration, ultrafiltration, and reverse osmosis, and various filtration techniques can be used. Examples of filters used for filtering include mesh filters, depth filters, and membrane filters. In filtering, the particle size distribution of the powder can be controlled by adjusting the filtration time, filtration rate, filtration accuracy, and the like. For example, the filtration accuracy can be 0.1 μm or more and 300 μm or less.

[0045] By appropriately selecting and / or combining one or more of the above-described firing method, pulverization method, and classification / filtering method, and controlling the respective conditions, alumina particles having an irregularity degree N and a distortion degree S that satisfy the relationships of the above formulas (2) and (4) can be obtained.

[0046] Note that commercially available products may be used as the alumina particles. Further, the alumina particles can be used alone or in combination of two or more kinds.

[0047] [Water] The polishing composition according to the present invention contains water. The water disperses or dissolves each component. From the viewpoint of preventing the influence of impurities on other components of the polishing composition, it is preferable to use water with as high purity as possible. Specifically, pure water or ultrapure water obtained by removing impurity ions with an ion exchange resin and then removing foreign substances through a filter, or distilled water is preferable. Further, for the purpose of controlling the dispersibility and the like of other components in the polishing composition, an organic solvent or the like as a dispersion medium may be further contained.

[0048] [Other components] The polishing composition according to the present invention may further contain known components such as a pH adjuster, a surfactant, a dispersant, a thickener (viscosity adjuster), a surface protector, a wetting agent, an oxidizing agent, a water-soluble polymer, a salt, a corrosion inhibitor, a preservative, and an antifungal agent within a range that does not impair the effects of the present invention. The content of these other components may be appropriately set according to the purpose of addition. Hereinafter, the pH adjuster, the surfactant, the dispersant, the thickener (viscosity adjuster), the oxidizing agent, the corrosion inhibitor, the preservative, and the antifungal agent will be described. Further, the chelating agent will also be described.

[0049] [pH adjuster] The polishing composition according to some embodiments of the present invention may further contain a pH adjuster. The pH adjuster can contribute to the adjustment of the pH of the polishing composition by selecting its type and addition amount.

[0050] The pH adjuster is not particularly limited as long as it is a compound having a pH adjusting function, and known compounds can be used. The pH adjuster is not particularly limited as long as it is a compound having a pH adjusting function, and examples thereof include acids and alkalis.

[0051] The acid may be either an inorganic acid or an organic acid. Inorganic acids include, but are not limited to, sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid. Organic acids include, but are not limited to, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, and lactic acid, as well as methanesulfonic acid, ethanesulfonic acid, and isethionic acid. Among these, organic acids are preferred, with malic acid, citric acid, and maleic acid being more preferred. When an inorganic acid is used, nitric acid, sulfuric acid, or phosphoric acid is preferred.

[0052] The alkali is not particularly limited, but examples thereof include hydroxides of alkali metals, salts of alkali metals, hydroxides of alkaline earth metals, salts of alkaline earth metals, quaternary ammonium, and ammonia.

[0053] Specific examples of alkali metals include potassium and sodium. Specific examples of alkaline earth metals include calcium and strontium. Specific examples of salts include carbonates, bicarbonates, sulfates, acetates, and the like. Specific examples of quaternary ammonium include tetramethylammonium, tetraethylammonium, tetrabutylammonium, and hydroxides thereof. Of these, potassium hydroxide or ammonia is preferred as the alkali.

[0054] The pH adjusters may be used singly or in combination of two or more.

[0055] The pH of the polishing composition according to some embodiments of the present invention is not particularly limited, but is preferably alkaline from the viewpoint of the polishing removal rate, and is preferably 8 or higher. The pH is more preferably 9 or higher, even more preferably 10 or higher, and particularly preferably 11 or higher. Furthermore, from the viewpoint of further improving the polishing removal rate of the resin material and reducing scratches, the pH is preferably 14 or lower, more preferably 13 or lower, and even more preferably 12 or lower. For example, the pH of the polishing composition can be in the range of 8 to 14, preferably 9 to 13, and more preferably 10 to 12. Within the above range, there is an effect of achieving a better balance between improving the polishing removal rate of the resin material and reducing scratches. The content of the pH adjuster is not particularly limited, and is preferably an amount that allows the pH value to fall within the above preferred range.

[0056] <Surfactant> The polishing composition according to some embodiments of the present invention may contain a surfactant. The surfactant that can be contained in the polishing composition of the present invention is at least one selected from the group consisting of anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. Of these, nonionic surfactants are preferred as the surfactant contained in the polishing composition. The surfactants can be used alone or in combination of two or more.

[0057] Examples of anionic surfactants include polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, alkyl ether sulfates, alkyl benzene sulfonates, alkyl phosphates, polyoxyethylene alkyl phosphates, polyoxyethylene sulfosuccinates, alkyl sulfosuccinates, alkyl naphthalene sulfonates, alkyl diphenyl ether disulfonates, and salts thereof.

[0058] Examples of cationic surfactants include alkyltrimethylammonium salts, alkyldimethylammonium salts, alkylbenzyldimethylammonium salts, and alkylamine salts.

[0059] Examples of amphoteric surfactants include alkyl betaines and alkyl amine oxides.

[0060] Examples of nonionic surfactants include polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ethers, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkylamines, and alkylalkanolamides.

[0061] When the polishing composition contains a surfactant, the content of the surfactant is preferably 0.01 mass% or more, more preferably 0.1 mass% or more, based on the total mass of the polishing composition.Furthermore, the content of the surfactant in the polishing composition is preferably 3.0 mass% or less, more preferably 2.0 mass% or less, based on the total mass of the polishing composition.If the content of the surfactant is within the above range, the polishing uniformity of the object to be polished is further improved.

[0062] <Dispersant / Thickener (Viscosity Adjuster)> The polishing composition according to some embodiments of the present invention may contain a dispersant or thickener (viscosity modifier). The dispersant or thickener serves to uniformly disperse the abrasive grains (alumina particles) in the liquid, thereby enabling the abrasive grains to efficiently act on the object to be polished. In addition, the presence of the dispersant or thickener between the abrasive grains is expected to suppress caking of the abrasive grains, thereby suppressing the occurrence of scratches caused by agglomerated abrasive grains.

[0063] Specific examples of dispersants include colloidal substances containing fine particles, such as colloidal alumina, colloidal silica, colloidal zirconia, colloidal titania, alumina sol, silica sol, zirconia sol, titania sol, fumed alumina, fumed silica, fumed zirconia, fumed titania, etc. Also, commonly used dispersants such as sodium phosphate, sodium hexametaphosphate, and sodium pyrophosphate may be used.

[0064] Specific examples of thickeners include glycols such as propylene glycol polymers and ethylene glycol polymers, and polymeric compounds. More specifically, glycols include propylene glycol, ethylene glycol, dipropylene glycol, polypropylene glycol, diethylene glycol, and polyethylene glycol. Polymeric compounds include sodium polyacrylate, polyvinyl alcohol, and hydroxyethyl cellulose.

[0065] <Oxidizing agent> When the object to be polished includes a metal material, the polishing composition according to some embodiments of the present invention may contain an oxidizing agent. The oxidizing agent oxidizes and hardens the surface of the metal material, thereby suppressing the occurrence of defects such as scratches. Specific examples of oxidizing agents include peroxides such as hydrogen peroxide, nitrates, iodates, periodates, hypochlorites, chlorites, chlorates, perchlorates, persulfates, dichromates, permanganates, ozone water, silver(II) salts, and iron(III) salts. The oxidizing agents may be used singly or in combination of two or more. Furthermore, commercially available or synthetic oxidizing agents may be used.

[0066] <Corrosion inhibitor> When the object to be polished includes a metal material, the polishing composition according to some embodiments of the present invention may contain a corrosion inhibitor. The corrosion inhibitor functions to prevent excessive dissolution of the metal material. Examples of corrosion inhibitors include heterocyclic compounds. The number of members of the heterocycle in the heterocyclic compound is not particularly limited. The heterocyclic compound may be a monocyclic compound or a polycyclic compound having condensed rings. The corrosion inhibitor may be used alone or in combination of two or more types. The corrosion inhibitor may be a commercially available product or a synthetic product.

[0067] Specific examples of heterocyclic compounds that can be used as anticorrosive agents include nitrogen-containing heterocyclic compounds such as pyrrole compounds, pyrazole compounds, imidazole compounds, triazole compounds, tetrazole compounds, pyridine compounds, pyrazine compounds, pyridazine compounds, pyrindine compounds, indolizine compounds, indole compounds, isoindole compounds, indazole compounds, purine compounds, quinolizine compounds, quinoline compounds, isoquinoline compounds, naphthyridine compounds, phthalazine compounds, quinoxaline compounds, quinazoline compounds, cinnoline compounds, buteridine compounds, thiazole compounds, isothiazole compounds, oxazole compounds, isoxazole compounds, and furazan compounds.

[0068] <Mold inhibitors, preservatives> The polishing composition according to some embodiments of the present invention may contain an antifungal agent or a preservative. Specific examples of the antifungal agent or preservative include isothiazolinone preservatives (e.g., 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one), paraoxybenzoic acid esters, and phenoxyethanol. These antifungal agents and preservatives may be used alone or in combination of two or more.

[0069] <Chelating agent> When the object to be polished includes a metal material, the polishing composition according to some embodiments of the present invention preferably contains substantially no chelating agent. This can suppress the increase in scratches and dishing on the surface of the metal material caused by the chelating agent in the polishing composition. Here, "the polishing composition is substantially free of chelating agent" means that a chelating agent is not added to the polishing composition, at least intentionally, and includes the concept of no chelating agent being contained in the polishing composition at all, as well as the case where the polishing composition contains 0.1% by mass or less of a chelating agent. The concentration (content) of the chelating agent is more preferably 0.05% by mass or less, and even more preferably 0.01% by mass or less, based on the total mass of the polishing composition. 0% by mass, i.e., no chelating agent is particularly preferred. Examples of chelating agents include aminocarboxylic acid chelating agents and organic phosphonic acid chelating agents.

[0070] [Polishing removal speed] The polishing composition according to some embodiments of the present invention can improve the polishing removal rate of resin materials. For example, the polishing removal rate of resin materials is preferably 2.0 μm / min or more, more preferably 2.3 μm / min or more, and even more preferably 2.5 μm / min or more. The polishing removal rate is determined by the method described in the examples.

[0071] [Method for producing polishing composition] In the polishing composition according to some embodiments of the present invention, the manufacturing method (preparation method) of the polishing composition is not particularly limited, and for example, can suitably adopt the manufacturing method comprising stirring and mixing alumina particles, water, and other components as required.In addition, alumina particles, water, and other components are the same as those described above, so description here is omitted.

[0072] The temperature at which the components of the polishing composition are mixed is not particularly limited, but is preferably 10° C. to 40° C. Heating may be performed to increase the dissolution rate. The mixing time is also not particularly limited.

[0073] [Polishing method] The second embodiment of the present invention relates to a polishing method comprising a step of polishing an object to be polished containing a resin material using the polishing composition described above. Preferred examples of the object to be polished according to this embodiment are the same as those described in the description of [Object to be polished].

[0074] Polishing an object to be polished using a polishing composition can be carried out using equipment and conditions commonly used for polishing. Common polishing equipment includes single-sided polishing equipment and double-sided polishing equipment. In single-sided polishing equipment, the object to be polished is generally held using a holder called a carrier, and while a polishing composition is supplied from above, a platen with a polishing pad attached is pressed against one side of the object to be polished and the platen is rotated to polish one side of the object to be polished. In double-sided polishing equipment, the object to be polished is generally held using a holder called a carrier, and while a polishing composition is supplied from above, a platen with a polishing pad attached is pressed against the opposite side of the object to be polished, and the plates are rotated in relative directions to polish both sides of the object to be polished. During this process, polishing is achieved by the physical action of friction between the polishing pad and polishing composition and the object to be polished, and the chemical action of the polishing composition on the object to be polished. Porous materials such as nonwoven fabrics, polyurethane, and suede can be used as the polishing pad without any particular restrictions. It is preferable that the polishing pad be treated to allow the polishing liquid to accumulate.

[0075] Examples of polishing conditions include polishing load, platen rotation speed, carrier rotation speed, flow rate of polishing composition, and polishing time. There are no particular limitations on these polishing conditions, but for example, the polishing load is preferably 0.1 psi (0.69 kPa) or more and 10 psi (69 kPa) or less per unit area of ​​the object to be polished, and more preferably 0.5 psi (3.5 kPa) or more and 8.0 psi (55 kPa) or less. Generally, the higher the load, the higher the frictional force caused by the abrasive grains, improving the mechanical processing force and increasing the polishing removal rate. Within this range, a sufficient polishing removal rate is achieved, and damage to the object to be polished due to the load and the occurrence of defects such as scratches on the surface can be suppressed. The platen rotation speed and carrier rotation speed are preferably 10 rpm (0.17 s -1 ) or more 500rpm(8.3s -1 ) or less. The supply amount of the polishing composition is only required to be a supply amount (flow rate) that covers the entire object to be polished, and may be adjusted depending on conditions such as the size of the object to be polished. The method of supplying the polishing composition to the polishing pad is not particularly limited, and for example, a method of continuously supplying the polishing composition using a pump or the like is used. In addition, the processing time is not particularly limited as long as it is a time that can obtain the desired processing results, but it is preferable to use a shorter time due to the high polishing removal rate.

[0076] A third embodiment of the present invention relates to a method for producing a polished object, which comprises polishing the object by the above-described polishing method. Preferred examples of the object to be polished according to this embodiment are the same as those described in the description of the "object to be polished." One preferred example is a method for producing an electronic circuit board, which includes polishing an object to be polished containing a resin material by the above-described polishing method.

[0077] Although the embodiments of the present invention have been described in detail, it is clear that this is for illustrative and exemplary purposes only and not for limitation, and that the scope of the present invention should be interpreted by the appended claims.

[0078] The present invention encompasses the following aspects and configurations: 1. A polishing composition used for polishing an object to be polished containing a resin material, Water and Alumina particles, Including, In the alumina particles, D2 is the particle size at which the cumulative frequency from the small particle size side in the volume-based particle size distribution is 2%, The particle size at which the cumulative frequency from the small particle size side in the volume-based particle size distribution is 50% is called D 50 year, The particle size at which the cumulative frequency from the small particle size side in the volume-based particle size distribution is 98% is defined as D 98 year, The BET specific surface area is SA, The above D 50 When the theoretical specific surface area calculated from the above is SA', A polishing composition in which the degree of irregularity N represented by the following formula (1) satisfies the relationship of the following formula (2), and the degree of distortion S represented by the following formula (3) satisfies the relationship of the following formula (4):

[0079]

number

[0080] 2. D of the alumina particles 50 The polishing composition according to 1. above, wherein the particle size is 0.2 μm or more and 0.4 μm or less. 3. The polishing composition according to 1. or 2. above, wherein the alumina particles have an gelatinization rate of 80% or more and 98% or less. 4. The polishing composition according to any one of 1. to 3. above, wherein the resin material contains polyimide. 5. The polishing composition according to any one of 1. to 4. above, wherein the object to be polished further contains a metal material. 6. The polishing composition according to any one of 1. to 5. above, which is substantially free of a chelating agent: 7. A polishing method comprising the step of polishing an object containing a resin material with the polishing composition according to any one of 1. to 6. above. [Example]

[0081] Examples of the present invention will be described below. However, the technical scope of the present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass", respectively.

[0082] (Preparation of Polishing Compositions of Examples 1 to 2 and Comparative Examples 1 to 11) Alumina particles as abrasive grains were mixed with pure water, and then crushed and classified appropriately. Then, potassium hydroxide was used as a pH adjuster to prepare a polishing composition with a pH value of 11.0 (mixing temperature: about 25°C, mixing time: about 30 minutes). The concentration of alumina particles in the polishing composition was 3.0% by mass.

[0083] The polishing composition obtained above was evaluated for the physical properties of the alumina particles, the polishing removal rate of polyimide, and scratches on the polyimide surface.

[0084] [evaluation] <D2, D of alumina particles 50 , D 98 > The alumina particles were measured using a laser diffraction particle size distribution analyzer (Microtrac particle size distribution analyzer MT3300EX II, manufactured by Microtrac-Bell Corporation) to determine the volumetric particle size distribution. In the obtained particle size distribution, the particle diameter at which the cumulative frequency from the small particle diameter side is 2% is defined as D2 of the alumina particles, and the particle diameter at which the cumulative frequency from the small particle diameter side is 50% is defined as D of the alumina particles. 50 The particle diameter at which the cumulative frequency from the small particle diameter side is 98% is defined as D of the alumina particles. 98 It was decided.

[0085] <BET specific surface area of ​​alumina particles> The BET specific surface area SA of the alumina particles was measured using a fully automatic specific surface area measuring device (Macsorb (registered trademark) HM model-1201) manufactured by Mountech Co., Ltd.

[0086] <Theoretical specific surface area SA' of alumina particles> The theoretical specific surface area SA' of the alumina particles is calculated by the above-measured D 50 The value was used to calculate the following formula (5).

[0087]

number

[0088] In the above formula (5), ρ is the density of the alumina particles, and is 3.95 g / cm 3 The value of was used.

[0089] D2 and D obtained above 50 , D 98 From SA and SA', the non-circularity N and the distortion S were calculated according to the following formulas (1) and (3).

[0090]

number

[0091] <Alpha conversion rate of alumina particles> The alpha phase ratio of the alumina particles was calculated using an X-ray diffractometer (Ultima-IV, manufactured by Rigaku Corporation). Commercially available alpha-alumina single crystal particles (alpha phase ratio: 100%), which had been sintered at a sufficiently high temperature to undergo sufficient alpha phase transformation, were used as the reference material. The alpha phase ratio of the alumina particles (abrasive grains) used as the reference material and the alumina particles (abrasive grains) was calculated from the integrated intensity ratio of the peak at 2θ = 43° ± 2° corresponding to the (113) plane measured using Cu-Kα radiation (see formula (6) below).

[0092]

number

[0093] <Evaluation of polishing removal rate and scratches> A polyimide (PI) substrate was prepared as the object to be polished, and polishing was performed using each polishing composition with the following polishing apparatus and under the following polishing conditions. The polishing removal rate of the polyimide of the polished object was evaluated according to the following (Polishing Removal Rate Evaluation Method), and scratches on the surface of the polished polyimide substrate were evaluated according to the following (Scratch Evaluation Method).

[0094] (Polished object) Polyimide substrate: Size: 30mm x 30mm (manufactured by Asahi Kasei Corporation, product name PIMEL BM302H) (Polishing equipment and polishing conditions) Polishing device: Small desktop polishing machine (Engis Japan Co., Ltd. EJ380IN) Surface plate diameter: 380 [mm] Polishing pad: Nonwoven fabric pad (Nitta DuPont SUBA800) Platen rotation speed: 340 rpm Head (carrier) rotation speed: 50 rpm Polishing pressure: 3.0 [psi] (210 [g / cm 2 ], 207kPa) Flow rate of polishing composition: 80 [ml / min] Polishing time: 1 min.

[0095] (Polishing removal rate evaluation method) 1. Using an analytical balance XS205 (Mettler-Toledo), the mass of the object to be polished was measured before and after polishing, and the mass change ΔM [kg] of the object to be polished before and after polishing was calculated from the difference between these values; 2. The change in mass of the object to be polished before and after polishing, ΔM (kg), is divided by the specific gravity of the object to be polished (specific gravity of the material to be polished) to obtain the change in volume of the object to be polished before and after polishing, ΔV (m 3 ] was calculated; 3. Volume change of the object to be polished before and after polishing ΔV [m 3 ] is the area s of the polishing surface of the object to be polished [m 2 ] to calculate the thickness change Δd [m] of the polished object before and after polishing; 4. The thickness change Δd (m) of the workpiece before and after polishing was divided by the polishing time t (min) and converted to μm / min. This value was used as the polishing removal rate v (μm / min).

[0096] (Scratch evaluation method) The polished surface of the polyimide substrate was visually observed, and scratches were evaluated according to the following evaluation criteria: 〇: No scratches can be seen visually under fluorescent light ×: Scratches can be visually confirmed under fluorescent light.

[0097] The evaluation results are shown in Table 1 below.

[0098] [Table 1]

[0099] As is clear from Table 1 above, the polishing compositions of the Examples were shown to be superior in both the polishing removal rate of polyimide and scratches on the polyimide surface after polishing. On the other hand, the polishing compositions of the Comparative Examples, in which either or both of the non-circularity N and the distortion S were outside the range of the present invention, were shown to be inferior to the Examples in either or both of the polishing removal rate of polyimide and scratches on the polyimide surface after polishing.

Claims

1. A polishing composition used for polishing an object to be polished containing a resin material, Water and Alumina particles, Including, In the alumina particles, The particle size at which the cumulative frequency from the small particle size side in the volume-based particle size distribution is 2% is defined as D ２ year, The particle size at which the cumulative frequency from the small particle size side in the volume-based particle size distribution is 50% is defined as D ５０ year, The particle size at which the cumulative frequency from the small particle size side in the volume-based particle size distribution is 98% is defined as D ９８ year, SA is the BET specific surface area, The above D ５０ When the theoretical specific surface area calculated from the above is SA', A polishing composition in which the irregularity N represented by the following formula (1) satisfies the relationship of the following formula (2), and the distortion S represented by the following formula (3) satisfies the relationship of the following formula (4). [Equation 1]

2. D of the alumina particles ５０ The polishing composition according to claim 1, wherein the particle size is 0.2 μm or more and 0.4 μm or less.

3. 2. The polishing composition according to claim 1, wherein the alumina particles have an alpha conversion rate of 80% or more and 98% or less.

4. The polishing composition according to claim 1 , wherein the resin material comprises polyimide.

5. The polishing composition according to claim 1 , wherein the object to be polished further comprises a metal material.

6. The polishing composition of claim 1 , which is substantially free of a chelating agent.

7. 7. A polishing method comprising a step of polishing an object containing a resin material with the polishing composition according to claim 1.

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