WO2015060410A1 - 研磨液組成物の製造方法 - Google Patents
研磨液組成物の製造方法 Download PDFInfo
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- WO2015060410A1 WO2015060410A1 PCT/JP2014/078272 JP2014078272W WO2015060410A1 WO 2015060410 A1 WO2015060410 A1 WO 2015060410A1 JP 2014078272 W JP2014078272 W JP 2014078272W WO 2015060410 A1 WO2015060410 A1 WO 2015060410A1
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- WIPO (PCT)
- Prior art keywords
- polishing
- acid
- less
- filter aid
- filter
- Prior art date
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Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
- G11B5/8404—Processes or apparatus specially adapted for manufacturing record carriers manufacturing base layers
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
- C09K3/14—Anti-slip materials; Abrasives
- C09K3/1454—Abrasive powders, suspensions and pastes for polishing
- C09K3/1463—Aqueous liquid suspensions
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09G—POLISHING COMPOSITIONS; SKI WAXES
- C09G1/00—Polishing compositions
- C09G1/02—Polishing compositions containing abrasives or grinding agents
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
- C09K3/14—Anti-slip materials; Abrasives
- C09K3/1409—Abrasive particles per se
Definitions
- the present disclosure relates to a manufacturing method of a polishing liquid composition, a polishing liquid composition, a manufacturing method of a magnetic disk substrate, and the like.
- Recent memory hard disk drives are required to have a high capacity and a small size, and to increase the recording density, it is required to reduce the flying height of the magnetic head and reduce the unit recording area. Accordingly, the surface quality required after polishing in the manufacturing process of the magnetic disk substrate is becoming stricter year by year. That is, it is necessary to reduce the surface roughness, micro waviness, roll-off and protrusions according to the low flying height of the head, and the allowable number of scratches per substrate surface is small according to the decrease in the unit recording area, Its size and depth are getting smaller and smaller.
- a polishing liquid with a reduced number of coarse particles using centrifugal separation or multi-stage filtration in order to reduce scratches (scratches) generated on the surface of the workpiece for the purpose of improving surface smoothness.
- Compositions and methods for producing the same have been proposed (for example, Patent Documents 1 and 2).
- polishing which passes a silica sol through a diatomaceous earth filter is proposed (for example, patent document 3 and 4).
- One embodiment of the present invention is capable of efficiently removing coarse particles and gelled substances in a silica dispersion to be treated containing colloidal silica, thereby providing high filtration accuracy and reducing the number of scratches on the substrate surface after polishing.
- the present invention relates to a method for producing a polishing composition that can be reduced.
- the present invention relates to a method for producing a polishing liquid composition
- a method for producing a polishing liquid composition comprising a step of subjecting a silica dispersion to be treated containing colloidal silica to a filtration treatment with a filter containing a filter aid (hereinafter referred to as “manufacturing the polishing liquid composition according to the present disclosure” Also referred to as “method”.)
- the average particle diameter of primary particles obtained by a titration method of colloidal silica is 1 nm or more and 50 nm or less.
- the hydroxyl group density of the filter aid is 0.40 ⁇ 10 ⁇ 5 mol / m 2 or more.
- the present invention relates to a polishing composition that can or can be produced by the method for producing a polishing composition according to the present disclosure.
- the polishing target surface is polished by supplying the polishing liquid composition obtained by the manufacturing method of the polishing liquid composition according to the present disclosure to the polishing target surface of the substrate to be polished.
- the present invention relates to a method of manufacturing a magnetic disk substrate including steps.
- the present invention relates to the filter aid used in the method for producing a polishing composition according to the present disclosure, wherein the hydroxyl group density of the filter aid is 0.40 ⁇ 10 ⁇ 5 mol / m 2 or more.
- the present invention relates to a method for producing a filter aid used in the method for producing a polishing liquid composition according to the present disclosure, and a diatomaceous earth and acid having a hydroxyl group density of less than 0.40 ⁇ 10 ⁇ 5 mol / m 2. After mixing with the aqueous solution, a step of deoxidizing the diatomaceous earth is included.
- a filter aid whose hydroxyl group density is controlled to a predetermined value or more is used as a filter aid in a filter containing a filter aid (hereinafter also referred to as “filter aid-containing filter”). Therefore, when the average particle diameter of the primary particles of colloidal silica is 1 nm or more and 50 nm or less, the filtration accuracy by the filter aid-containing filter of coarse particles and gelled product is high. Therefore, if the polishing composition produced by the method for producing a polishing composition of the present invention is used, scratches on the substrate surface after polishing can be reduced.
- the term “coarse particles” refers to coarse colloidal silica particles having a particle diameter of 0.5 ⁇ m or more.
- the “gelled product” refers to a silica aggregate of 0.05 to 0.5 ⁇ m. The amount of coarse particles and gelled product in the polishing composition can be evaluated by the “0.45 ⁇ m filter flow rate” described later.
- “scratch” is a physical property that is important for high density or high integration in a memory hard disk substrate or a semiconductor device substrate, and has a depth of 1 nm or more and less than 100 nm, a width of 5 nm or more, and less than 500 nm. It is a fine scratch on the surface of the substrate having a length of 100 ⁇ m or more. This scratch can be detected using an optical full-surface defect inspection machine (OSA6100: manufactured by KLA-Tencor) and an atomic force microscope (AFM) described in Examples described later.
- OSA6100 optical full-surface defect inspection machine
- AFM atomic force microscope
- filtration accuracy means the degree to which coarse particles and gelled product are filtered by the filter aid-containing filter
- high filtration accuracy means coarse particles and gel by the filter aid-containing filter. This means that the capture rate of the compound is high.
- “Filtration accuracy” is measured by passing the polishing composition or silica dispersion through a predetermined filter aid-containing filter under a certain pressure, until the filter aid-containing filter is blocked. It can be evaluated by the liquid volume (g). The liquid flow rate can be expressed as a microfiltration value (MF value). A larger amount of liquid flow, that is, a larger MF value means that coarse particles and gelled products are not mixed in the polishing composition or silica dispersion, and the filtration accuracy is high.
- MF value microfiltration value
- the silica dispersion having a large MF value is a silica dispersion capable of reducing the number of scratches.
- the polishing liquid composition prepared using the silica dispersion liquid with a large MF value is a polishing liquid composition capable of reducing the number of scratches.
- the mechanism for reducing the number of scratches in the present invention is estimated as follows.
- a filter aid-containing filter When removing coarse particles and gelled products of colloidal silica from a treated silica dispersion containing colloidal silica using a filter aid-containing filter, the submicron small amount present in the filter aid itself of the filter aid-containing filter is used.
- the filter or filter aid-containing filter includes a filter aid layer (cake layer), the coarse particles and the gelled product are trapped by the interparticle gap formed by the filter aid inside the filter aid layer. Is done.
- a filter aid having a hydroxyl group density higher than that of conventionally used filter aids and having a hydroxyl group density of 0.40 ⁇ 10 ⁇ 5 mol / m 2 or more is used.
- the filter aid used in the present invention has a higher frequency of interaction and hydrogen bonding with the hydroxyl groups of the filter aid, the coarse particles and the gelled product than the conventionally used filter aids. Therefore, in the present invention, trapping by physical barriers such as the small holes and the interparticle gaps is promoted by the interaction, and the trapping of the coarse particles and the gelled product is performed more effectively. As a result, it is considered that the filtration accuracy of the polishing composition and the silica dispersion is increased, and the number of scratches can be reduced.
- the present invention is not construed as being limited to these mechanisms.
- the filter aid used in the method for producing a polishing composition according to the present disclosure includes insoluble mineral substances such as diatomaceous earth, silica, kaolin, acid clay, pearlite, bentonite, and talc. Can be mentioned.
- insoluble mineral substances such as diatomaceous earth, silica, kaolin, acid clay, pearlite, bentonite, and talc.
- silicon dioxide, diatomaceous earth and pearlite are preferred, diatomaceous earth and pearlite are more preferred, and diatomaceous earth is still more preferred, from the viewpoints of reducing coarse particles and gelled products and reducing scratches on the substrate surface after polishing.
- the hydroxyl group density of the filter aid (preferably diatomaceous earth) is 0.40 ⁇ 10 ⁇ 5 mol / m 2 or more, preferably 0.41 ⁇ 10 ⁇ 5 mol / m 2 or more, from the viewpoint of improving filtration accuracy. 0.43 ⁇ 10 ⁇ 5 mol / m 2 or more is preferable, and from the viewpoint of improving productivity, 2.0 ⁇ 10 ⁇ 5 mol / m 2 or less is preferable, and 1.5 ⁇ 10 ⁇ 5 mol / m 2. The following is more preferable.
- the hydroxyl group density of the filter aid can be determined by the method described in the examples.
- the hydroxyl group density of the filter aid can be controlled as follows.
- a hydroxyl group can be introduced into diatomaceous earth without changing physical properties such as average pore diameter, pore volume and CV value for the filter aid. Therefore, if the polishing liquid composition produced by the method for producing the polishing liquid composition of the present invention is used, a conventional filter aid whose hydroxyl group density is not controlled to 0.40 ⁇ 10 ⁇ 5 mol / m 2 or more can be obtained. Polishing at a polishing rate equivalent to that of the polishing liquid composition produced using the same and reduction of scratches can be achieved.
- diatomaceous earth is washed with ion-exchanged water or ultrapure water, and the washing is repeated until the ion-exchanged water or ultrapure water used for washing becomes almost neutral.
- ion-exchanged water or ultrapure water is added to the residue of the mixture (diatomaceous earth) from which the supernatant has been removed. Stir and mix thoroughly.
- the diatomaceous earth After washing the diatomaceous earth with ion-exchanged water or ultrapure water, the diatomaceous earth has a higher hydroxyl group density than diatomaceous earth that has not been treated with an acid by filtering the diatomaceous earth on a filter paper and drying the diatomaceous earth by, for example, natural drying. Is obtained.
- the amount of hydroxyl group introduced can be controlled by the acid concentration in the acid aqueous solution, the diatomaceous earth immersion time in the acid aqueous solution, and the like. Although the mechanism for increasing the hydroxyl group density cannot be determined, the following two mechanisms are presumed.
- metal oxides such as Al 2 O 3 , FeO 2 , and MgO present on the surface of diatomaceous earth are eluted, resulting in the appearance of a new surface of diatomaceous earth.
- the hydroxyl density increases.
- the bond between the oxygen atom and the metal species such as Al, Fe, Mg, etc., which forms the diatomaceous earth skeleton, and the hydrogen atom in the aqueous solution binds to the oxygen atom.
- the hydroxyl group density is increased.
- the acid used for the preparation of the acid aqueous solution includes an inorganic acid and an organic acid.
- the inorganic acid a mineral acid is preferable.
- Various organic acids can be used as the organic acid, and it has been found that the improvement of the hydroxyl density of diatomaceous earth has a strong correlation with the acid dissociation constant (pKa). That is, the pKa of the organic acid is preferably less than 5 and more preferably lower from the viewpoint of improving the hydroxyl density of diatomaceous earth.
- the lower limit is not particularly limited, but the pKa of the organic acid is preferably 1 or more practically.
- the specific acid used for the preparation of the acid aqueous solution is, in one or more embodiments, hydrochloric acid, nitric acid, phosphoric acid, 1-hydroxyethylidene, from the viewpoint of improving filtration accuracy and reducing the number of scratches.
- At least one selected from the group consisting of phosphonic acids such as -1,1-diphosphonic acid, phosphinic acid, and organic acids having a pKa of less than 4 is preferred, hydrochloric acid, nitric acid, phosphoric acid, phosphonic acid, phosphinic acid, and pKa3 More preferably, at least one selected from the group consisting of organic acids less than .5, and more preferably at least one selected from the group consisting of nitric acid, phosphoric acid, phosphonic acid, phosphinic acid, and organic acids having a pKa of 3.1 or less. Even more preferred is at least one selected from the group consisting of phosphonic acid and phosphinic acid.
- the concentration of the acid in the aqueous acid solution is preferably 0.05 mol / L or more, more preferably 0.1 mol / L or more, from the viewpoint of improving the density of hydroxyl groups by securing a sufficient amount of elution of metal species. 15 mol / L or more is more preferable, and from the viewpoint of suppressing excessive elution of metal species, 2.0 mol / L or less is preferable, and 1.0 mol / l or less is more preferable.
- the amount of acid in the acid aqueous solution is 100 masses of diatomaceous earth to be mixed when using a 3.5 mass% acid aqueous solution from the viewpoint of securing a sufficient amount of metal species to be eluted and improving the hydroxyl group density.
- the amount is preferably 200 parts by mass or more, more preferably 500 parts by mass or more, and still more preferably 10,000 parts by mass or more.
- the standing time of the mixed solution of silicon earth and the acid aqueous solution is preferably 5 minutes or more, and preferably 30 minutes or more from the viewpoint of improving the hydroxyl group density by securing a sufficient amount of elution of the metal species. More preferably, it is more preferably 1 hour or longer, and preferably 72 hours or shorter from the viewpoint of productivity.
- Hydroxyl groups can also be introduced into diatomaceous earth by a method of dealkalization treatment (treatment with alkali).
- diatomaceous earth which is an example of a filter aid
- the diatomaceous earth is fired in a state where the diatomaceous earth is placed in the firing furnace, and the temperature in the firing furnace is from room temperature to preferably 700 ° C, more preferably to 750 ° C, and further The temperature is preferably increased to 800 ° C., and the temperature is preferably maintained for 3 hours or more, more preferably 5 hours or more, and even more preferably 10 hours or more.
- the temperature rise in the firing furnace is preferably performed by air flow from the viewpoint of improving the uniformity of the temperature in the firing furnace, and the wind speed is preferably 0.5 to 5 L / min, and 2 to 3 L / min. More preferably, it is min.
- the CV value is calculated by dividing the arithmetic standard deviation obtained by measuring the filter aid with a laser diffraction / scattering particle size distribution meter by the value obtained as the volume-based median diameter. It is calculated as a percentage (%), and in the present disclosure, it is a value calculated by measuring the scattering intensity distribution obtained by the Marquardt method at a detection angle of 90 °. Specifically, it can be determined by the method described in the examples.
- the CV value of the particle size distribution of the filter aid is preferably 70% or more, more preferably 75% or more, and more preferably 80% or more from the viewpoints of reducing coarse particles and gelated products and reducing scratches on the substrate surface after polishing. Is more preferable, 85% or more is still more preferable, and from the viewpoint of availability, 100% or less is preferable, and 99% or less is more preferable.
- the “laser average particle size” of the filter aid is an average particle size of the filter aid measured by a laser-type particle size distribution measuring device.
- the Marquardt method at a detection angle of 90 ° is used. The value was calculated by measuring the obtained scattering intensity distribution.
- the laser average particle diameter of the filter aid can be measured by the method described in Examples.
- the laser average particle diameter of the filter aid is preferably 0.5 ⁇ m or more, more preferably 1 ⁇ m or more, and further preferably 4.5 ⁇ m, from the viewpoint of reducing coarse particles and gelled products and reducing scratches on the substrate surface after polishing. From the same viewpoint, it is preferably 100 ⁇ m or less, more preferably 60 ⁇ m or less, still more preferably 50 ⁇ m or less, still more preferably 40 ⁇ m or less, and even more preferably from 8 ⁇ m or more, even more preferably 8 ⁇ m or more. Is 20 ⁇ m or less, and even more preferably 13 ⁇ m or less.
- the average pore diameter of the filter aid by mercury porosimetry is preferably from 0.1 to 3.5 ⁇ m, more preferably from the viewpoint of reducing scratches and particles and improving the productivity of the polishing composition. It is ⁇ 3.0 ⁇ m, more preferably 0.1 to 2.7 ⁇ m, still more preferably 0.1 to 2.6 ⁇ m.
- “average pore diameter by mercury porosimetry” is an average value of volume-based pore diameters of filter aid particles.
- Ratio of average particle diameter of primary particles of colloidal silica / laser average particle diameter of filter aid Ratio of average particle diameter of primary particles obtained by titration method of colloidal silica of silica dispersion to be treated to laser average particle diameter of filter aid (average particle diameter of primary particles of colloidal silica / laser average particle diameter of filter aid) ) (Hereinafter also referred to as “silica / filter aid average particle size ratio”) is 1.20 ⁇ 10 ⁇ in terms of reducing coarse particles and gelled products and reducing scratches on the substrate surface after polishing.
- the average particle size ratio of silica / filter aid is preferably 4.20 ⁇ 10 ⁇ 3 or less, more preferably 3.80 ⁇ 10 ⁇ 3 or less, and 3.00 ⁇ 10 ⁇ 3 or less. Is more preferably 2.50 ⁇ 10 ⁇ 3 or less, still more preferably 2.00 ⁇ 10 ⁇ 3 or less, and even more preferably 1.50 ⁇ 10 ⁇ 3 or less.
- the cumulative pore volume with a pore size of 0.15 ⁇ m or less by the nitrogen adsorption method of the filter aid is preferably 0.3 mL / g or more, more preferably 0.4 mL / g or more. More preferably, it is 0.6 mL / g or more.
- the integrated pore volume is preferably 100.0 mL / g or less, more preferably 50.0 mL / g or less, and further preferably 10.0 mL / g or less, from the viewpoint of improving the productivity of the polishing composition. is there.
- the cumulative pore volume of 0.15 ⁇ m or less of the filter aid can be measured by the method described in the examples.
- the cumulative pore volume of pore size of 0.5 ⁇ m or less by the mercury intrusion method of the filter aid is preferably 2.5 mL / g or more, more preferably 2.7 mL / g or more, from the viewpoint of reducing scratches and particles. More preferably, it is 3.0 mL / g or more, More preferably, it is 4.0 mL / g or more, More preferably, it is 4.5 mL / g or more.
- the cumulative pore volume of the filter aid with a pore diameter of 0.5 ⁇ m or less by the mercury intrusion method is preferably 1000 mL / g or less, more preferably 100 mL / g.
- it is more preferably 50 mL / g or less, still more preferably 20 mL / g or less, and still more preferably 10 mL / g or less.
- the cumulative pore volume of 0.5 ⁇ m or less by the mercury intrusion method” of the filter aid is the sum of the pore volumes of 0.5 ⁇ m or less in the volume-based pore distribution of the filter aid particles by the mercury intrusion method. It can be measured by the method described in the examples.
- the “treated silica dispersion” refers to a silica slurry (silica dispersion) before being subjected to a filtration treatment using a filter aid-containing filter.
- the silica dispersion to be treated includes those composed of colloidal silica and water, further containing other components, or a slurry of general-purpose colloidal silica.
- the silica dispersion to be treated includes those prepared by mixing other components that can be blended in the polishing composition described below.
- the state of the silica dispersion to be treated is preferably a state in which colloidal silica is dispersed.
- the silica dispersion to be treated is subjected to filtration using a filter containing the filter aid (also referred to as “filter aid-containing filter” in the present disclosure).
- a polishing liquid composition can be produced. Specifically, colloidal silica, treated silica dispersion prepared by mixing water and other components such as acid and oxidizing agent is subjected to the filtration, or treated silica containing colloidal silica and water. After subjecting the dispersion to the filtration, the polishing composition can be produced by mixing other components with the obtained filtrate (silica dispersion).
- the treated silica dispersion containing colloidal silica and water is subjected to the filtration, and the obtained filtrate (silica dispersion) is used as another component.
- the manufacturing method of the polishing liquid composition mixed with is preferable.
- the average particle diameter of primary particles of colloidal silica in the silica dispersion to be treated refers to the average particle diameter of primary particles determined by a titration method unless otherwise specified.
- the measurement of the average particle diameter of the primary particles by the titration method is specifically as described below. First, water is added to the colloidal silica slurry to obtain a mixed solution. Next, the pH of the mixed solution is adjusted with a hydrochloric acid standard solution or the like using a potentiometric titrator (for example, 3.0).
- the average particle diameter of the primary particles of colloidal silica in the silica dispersion to be treated is 1.0 nm or more and 50 nm or less from the viewpoint of reducing coarse particles and gelled products and reducing scratches on the substrate surface after polishing. In view of the above, it is more preferably 5.0 nm or more, still more preferably 10.0 nm or more, still more preferably 12.0 nm or more, preferably 45 nm or less, more preferably 42 nm or less, still more preferably 40 nm or less.
- the silica dispersion to be treated and the polishing liquid composition in the present disclosure refer to those containing colloidal silica having an average particle diameter of primary particles in the above range.
- the colloidal silica used in the present disclosure can be obtained, for example, by a production method that is generated from a silicic acid aqueous solution.
- those obtained by surface modification or surface modification of these abrasive particles with functional groups, those obtained by compounding with surfactants or other abrasives, and the like can also be used.
- the content of colloidal silica in the silica dispersion to be treated is preferably 1% by mass or more, more preferably 10% by mass or more, and still more preferably 20% by mass from the viewpoint of reducing scratches and improving productivity. More preferably, it is 30% by mass or more, preferably 50% by mass or less, more preferably 45% by mass or less, still more preferably 43% by mass or less, and still more preferably 40% by mass or less.
- the pH of the silica dispersion to be treated is preferably 8.5 or more, more preferably 8.8, from the viewpoint of suppressing the generation of coarse particles and improving the stability of colloidal silica. More preferably, it is 9.0 or more, preferably 11 or less, more preferably 10.8 or less, and still more preferably 10.5 or less.
- the pH of the silica particle dispersion to be treated can be adjusted with a known pH adjusting agent.
- Preferred pH adjusting agents include sodium hydroxide, potassium hydroxide, ammonia, and tetramethylammonium hydroxide.
- the filter aid-containing filter used in the method for producing a polishing composition according to the present disclosure is not particularly limited as long as it contains the filter aid on the filter surface and / or inside the filter.
- a pre-coat may be used in combination with a body feed.
- the filter opening measured by the method defined in JIS3801 is preferably 15 ⁇ m or less, more preferably 12 ⁇ m or less, still more preferably 10 ⁇ m or less, and even more preferably 8 ⁇ m or less, from the viewpoint of preventing leakage of the filter aid. .
- the filter opening is preferably 0.5 ⁇ m or more, more preferably 1.0 ⁇ m or more, still more preferably 3.0 ⁇ m or more, and even more preferably 5.0 ⁇ m or more.
- pre-coating is a method for forming a cake filtration filter, which is to form a thin layer of a filter aid having a thickness of about several millimeters on a filter material (substrate such as filter paper) described later.
- a method of dispersing filter aid particles in water and scraping the filter aid with a filter medium to form a filter aid layer can be mentioned.
- Body feed is a method in which a certain amount of filter aid is added to a stock solution that is subjected to cake filtration during filtration, and the purpose is to improve the filterability of the stock solution. This is effective for a stock solution that has a fine particle size and immediately has a maximum cake resistance (cannot be filtered).
- the content of the filter aid in the filter aid containing filter (g / cm 2), from the viewpoint of reducing scratches, preferably 0.001 g / cm 2 or more, more preferably 0.005 g / cm 2 or more, more preferably It is 0.01 g / cm 2 or more, still more preferably 0.02 g / cm 2 or more, still more preferably 0.04 g / cm 2 or more, and even more preferably 0.1 g / cm 2 or more. Further, from the viewpoint of improving the filtration rate, it is preferably 1 g / cm 2 or less, more preferably 0.8 g / cm 2 or less, still more preferably 0.6 g / cm 2 or less, and even more preferably 0.4 g / cm 2. Hereinafter, it is still more preferably 0.3 g / cm 2 or less, and still more preferably 0.2 g / cm 2 or less.
- filter paper examples include filter paper, polyethylene, polypropylene, polyethersulfone, cellulose acetate, nylon, polycarbonate, Teflon (registered trademark) plastic, ceramic, metal mesh, and the like. From the viewpoint of reduction, filter paper, polyethylene, polypropylene, polyethersulfone, cellulose acetate, nylon, polycarbonate, or plastic mesh made of Teflon (registered trademark) is preferable. Filter paper, polyethylene, polypropylene, polyethersulfone, cellulose acetate, or nylon A plastic mesh made of filter paper, polyethylene or polypropylene is more preferable.
- the opening of the filter material (base material) is preferably 15 ⁇ m or less, more preferably 12 ⁇ m or less, still more preferably 10 ⁇ m or less, and even more preferably 8 ⁇ m or less, from the viewpoint of preventing leakage of the filter aid. Further, from the viewpoint of improving the filter flow rate, the opening of the filter material (base material) is preferably 0.5 ⁇ m or more, more preferably 1.0 ⁇ m or more, still more preferably 3.0 ⁇ m or more, and even more preferably. It is 5.0 ⁇ m or more.
- the shape of the filter aid-containing filter is not particularly limited, but from the viewpoint of ease of handling and scratch reduction, sheet type, cylindrical type, disk type, folding type is preferable, sheet type, disk type, folding type is more preferable, A disk type and a folding type are more preferable.
- the filtration pressure among the conditions of the filtration treatment with a filter aid-containing filter is reduced coarse particles and gelled products, and the substrate surface after polishing From the viewpoint of reducing scratches, it is preferably 0.16 MPa or more, more preferably 0.18 MPa or more, and further preferably 0.20 MPa or more. From the same viewpoint, the filtration pressure in the filtration treatment step is preferably 0.49 MPa or less, more preferably 0.45 MPa or less, still more preferably 0.40 MPa or less, and even more preferably 0.30 MPa or less.
- the “filtration pressure” is a pressure per unit area applied to the filter aid, and can be adjusted by adjusting the output pressure with a regulator in one or a plurality of embodiments.
- the filtration flow rate among the conditions of the filtration treatment with a filter aid-containing filter is the reduction of coarse particles and gelled products, and the substrate surface after polishing From the standpoint of reducing the scratches, it is preferably 10.0 g / (min ⁇ m 2 ) or more, more preferably 12.0 g / (min ⁇ m 2 ) or more, still more preferably 14.0 g / (min ⁇ m 2 ). That's it.
- Filtration flow rate of filtration treatment step from the same viewpoint, preferable to be 40.0 g / (min ⁇ m 2) or less, more preferably 38.0 g / (min ⁇ m 2) or less, more preferably 36.0g / (Min ⁇ m 2 ) or less.
- the “filtration flow rate” is a weight per unit time that is filtered, and in one or a plurality of embodiments, by adjusting a secondary valve that is a filter outlet. Can be adjusted.
- the number of stages of the filter aid-containing filter is preferably 1 to 5 stages, more preferably 1 to 3 stages, and even more preferably 1 to 2 stages from the viewpoint of improving both filtration accuracy and productivity.
- a depth type filter or a pleat type filter conventionally used for the production of a polishing liquid composition, so that coarse particles and gels are used. It is preferable from the viewpoint of reduction of chemical compounds and reduction of scratches on the substrate surface after polishing.
- a manufacturing method of a polishing liquid composition according to the present disclosure includes a silica dispersion to be processed from the viewpoint of reducing coarse particles and gelled products and reducing scratches on a substrate surface after polishing.
- a filter aid-containing filter After filtering with a depth type filter, it is preferable to filter with a filter aid-containing filter, more preferably with a filter aid-containing filter, and further with a pleated filter.
- the depth filter has a feature that the pore structure of the filter medium is rough on the inlet side, finer on the outlet side, and finer continuously or stepwise from the inlet side to the outlet side. That is, among coarse particles, large particles are collected in the vicinity of the inlet side, and small particles are collected in the vicinity of the outlet side, so that effective filtration is possible.
- the shape of the depth filter may be a bag-like bag type or a hollow cylindrical cartridge type.
- a filter material having the above-described characteristics that is simply formed into a pleat shape has a function of a depth filter and is classified as a depth filter.
- the depth filter may be used in a single stage, or may be used in combination in multiple stages (for example, in a serial arrangement). From the viewpoint of improving productivity, filters having different hole diameters are arranged in multiple stages in the order of larger holes. It is preferable to make it. Moreover, you may use combining a bag type and a cartridge type.
- a filter material is generally formed into a pleated shape to form a hollow cylindrical cartridge type.
- a pleated filter used in the method for producing a polishing liquid composition or a silica dispersion according to the present disclosure
- a filter material is generally formed into a pleated shape to form a hollow cylindrical cartridge type.
- Advancedtech Toyo, Nippon Pole, CUNO, Daiwabo, etc. can be used.
- pleated filters are said to have a thin filter material and are mainly collected on the filter surface, and generally have high filtration accuracy. It is a feature.
- the pleated filter may be used in one stage, or may be used in combination in multiple stages (for example, in a series arrangement).
- the filter life can be prolonged as a whole by performing filtration with a depth filter, filtration with a filter aid-containing filter, and filtration with a pleated filter, and the polishing composition or silica dispersion according to the present disclosure can be extended. This is preferable because the liquid can be produced economically.
- the filtration method may be a recirculation type that repeatedly filters or a one-pass method.
- a batch method that repeats the one-pass method may be used.
- the circulation method preferably uses a pump in the circulation type, and uses a pump in the one-pass system.
- a pressure filtration with a small fluctuation range of the filter inlet pressure by introducing air pressure or the like into the tank. Can be used.
- a general particle dispersion step or particle removal step may be provided in addition to using the depth filter or the pleated filter.
- a dispersion process using a high-pressure dispersion apparatus such as a high-speed dispersion apparatus or a high-pressure homogenizer, or a coarse particle sedimentation process using a centrifugal separator or the like can be used.
- a high-pressure dispersion apparatus such as a high-speed dispersion apparatus or a high-pressure homogenizer, or a coarse particle sedimentation process using a centrifugal separator or the like
- each may be processed independently or may be processed in combination of two or more, and there is no limitation on the processing order of the combination. Further, the processing conditions and the number of processing times can be appropriately selected and used.
- the 0.45 ⁇ m filter flow rate of the polishing composition / silica dispersion is a measure of the abundance of coarse particles and gelled products.
- the “0.45 ⁇ m filter flow rate” is the average of the primary particles of silica particles It is suitable as a parameter for comparing polishing liquid compositions / silica dispersions having the same particle size.
- the 0.45 ⁇ m filter flow rate of the polishing composition or silica dispersion (filtered silica dispersion to be treated) according to the present disclosure is preferably 100 mL or more, and 120 mL or more from the viewpoint of reducing scratches. Is more preferable, 140 mL or more is further preferable, 150 mL or more is even more preferable, and 180 mL or more is even more preferable.
- the 0.45 ⁇ m filter flow rate of the polishing composition or the silica dispersion can be measured by the method described in the examples.
- the present disclosure includes a step of filtering a treated silica dispersion containing colloidal silica with a filter containing a filter aid, and the average particle size of primary particles obtained by the colloidal silica titration method.
- the present invention relates to a method for producing a silica dispersion, wherein the diameter is 1 nm or more and 50 nm or less, and the hydroxyl group density of the filter aid is 0.40 ⁇ 10 ⁇ 5 mol / m 2 or more.
- the silica dispersion obtained by the production method can produce a polishing composition with high filtration accuracy according to the present disclosure described later, and scratches on the substrate surface after polishing. Can be produced.
- the present disclosure relates to a polishing liquid composition (hereinafter, also referred to as “polishing liquid composition according to the present disclosure”) that is or can be manufactured by a method for manufacturing a polishing liquid composition.
- the polishing liquid composition according to the present disclosure includes a form containing an acid or a salt thereof, an alkali, and / or an oxidizing agent described later in addition to colloidal silica and water.
- the polishing composition according to the present disclosure is not limited to these compositions and may contain other components.
- the polishing liquid composition according to the present disclosure is obtained by mixing other components as necessary with the silica dispersion obtained by the method for producing a silica dispersion according to the present disclosure. It is a polishing liquid composition.
- the content of colloidal silica in the polishing composition according to the present disclosure when polishing an object to be polished is preferably 0.5% by mass or more, more preferably 1% by mass or more, from the viewpoint of improving the polishing rate. More preferably 2% by mass or more, more preferably 4% by mass or more, and from the viewpoint of economically improving the surface quality, it is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 13% by mass. Hereinafter, it is still more preferably 10% by mass or less, and still more preferably 8% by mass or less.
- water used in the polishing composition according to the present disclosure examples include ion exchange water, distilled water, and ultrapure water.
- the content of water in the polishing composition according to the present disclosure corresponds to the balance excluding the abrasive and other components from 100% by mass, preferably 60 to 99% by mass, and more preferably 80 to 97% by mass. .
- the pH at 25 ° C. of the polishing composition according to the present disclosure may be appropriately adjusted depending on the polishing target, but is preferably 0.1 or more and 7.0 or less. In alkaline, scratches tend to occur more easily than acidic. The generation mechanism is not clear, but in an alkaline atmosphere in which abrasive particles repel each other due to surface charge, aggregates or coarse particles of the primary particles of the abrasive contained in the polishing composition are subject to polishing. It is presumed that the load is applied non-uniformly over the entire polishing surface to prevent the polishing material from being closely packed between the polishing pad and the polishing pad.
- the pH is preferably determined according to the type of the object to be polished and the required characteristics.
- the material of the object to be polished is a metal material
- it is preferably 6.0 or less, more preferably 5 from the viewpoint of improving the polishing rate.
- 0.0 or less still more preferably 4.0 or less, even more preferably 3.0 or less, and even more preferably 2.0 or less.
- the pH is more preferably 0.5 or more, still more preferably 0.7 or more, and even more preferably 0.9 or more. Is more preferably 1.0 or more, still more preferably 1.2 or more.
- the material of the object to be polished is a metal material, such as a nickel-phosphorus (Ni-P) plated aluminum alloy substrate, and the object to be polished is a precision component substrate
- the pH is more preferably 0.5 or more and 6.0 or less, still more preferably 0.7 or more and 5.0 or less, and still more preferably. Is 0.9 or more and 4.0 or less, still more preferably 1.0 or more and 3.0 or less, and still more preferably 1.0 or more and 2.0 or less.
- the polishing composition according to the present disclosure may contain an acid or a salt thereof from the viewpoint of improving the polishing rate.
- the acid and its salt include inorganic acids such as nitric acid, sulfuric acid, nitrous acid, persulfuric acid, hydrochloric acid, perchloric acid, phosphoric acid, phosphonic acid, phosphinic acid, pyrophosphoric acid, tripolyphosphoric acid, and amidosulfuric acid.
- 2-aminoethylphosphonic acid 1-hydroxyethylidene-1,1-diphosphonic acid, hydroxyphosphonoacetic acid (PHAA), aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta ( Methylenephosphonic acid), ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, ethane-1-hydroxy-1,1,2- Triphosphonic acid, ethane-1,2-dicarboxy-1,2-diphosphonic acid, methanehydroxyphosphonic acid, Organics such as phosphonobutane-1,2-dicarboxylic acid, 2-phosphono-1,2,4-butanetricarboxylic acid (PBTC), 1-phosphonobutane-2,3,4-tricarboxylic acid, ⁇ -methylphosphonosuccinic acid Examples thereof include phosphonic acids or salt
- nitric acid, sulfuric acid, hydrochloric acid, perchloric acid or salts thereof are more preferable.
- organic phosphonic acids or salts thereof 1-hydroxyethylidene-1,1-diphosphone is preferred. Acid, hydroxyphosphonoacetic acid, aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid), 2-phosphono-1,2,4-butanetricarboxylic acid or a salt thereof is more preferable 1-hydroxyethylidene-1,1-diphosphonic acid is more preferred. You may use these individually or in mixture of 2 or more types.
- the acid salt is not particularly limited, and specific examples include salts with metals, ammonia, and alkylamines.
- Specific examples of the metal include metals belonging to 1A, 1B, 2A, 2B, 3A, 3B, 4A, 6A, 7A, or Group 8 of the periodic table (long period type). From the viewpoint of reducing scratches, ammonia or a metal belonging to Group 1A is preferable.
- the content of the acid and its salt in the polishing composition according to the present disclosure is preferably 0.001% by mass or more and 5% by mass or less from the viewpoint of improving the polishing rate and reducing scratches on the substrate surface after polishing.
- they are 0.01 mass% or more and 4 mass% or less, More preferably, they are 0.05 mass% or more and 3 mass% or less, More preferably, they are 0.1 mass% or more and 2.0 mass% or less, More preferably, It is 0.1 mass% or more and 1.0 mass% or less.
- the polishing composition according to the present disclosure preferably contains an oxidizing agent from the viewpoint of improving the polishing rate.
- an oxidizing agent that can be used in the polishing liquid composition according to the present disclosure from the viewpoint of improving the polishing rate, peroxide, permanganic acid or a salt thereof, chromic acid or a salt thereof, peroxo acid or a salt thereof, oxygen acid or The salt, metal salt, nitric acid, sulfuric acid etc. are mentioned.
- Examples of the peroxide include hydrogen peroxide, sodium peroxide, barium peroxide, etc.
- examples of the permanganic acid or salt thereof include potassium permanganate
- examples of the chromic acid or salt thereof include chromium.
- Peroxoacids or salts thereof include peroxodisulfuric acid, ammonium peroxodisulfate, metal peroxodisulfate, peroxophosphoric acid, peroxosulfuric acid, sodium peroxoborate, and performic acid.
- Peroxyacetic acid, perbenzoic acid, perphthalic acid, etc., and oxygen acids or salts thereof include hypochlorous acid, hypobromite, hypoiodous acid, chloric acid, bromic acid, iodic acid, hypochlorous acid. Examples thereof include sodium chlorate and calcium hypochlorite.
- Metal salts include iron chloride (III), iron sulfate (III), iron nitrate (III), citric acid (III), ammonium iron (III), and the like.
- the oxidizing agent include hydrogen peroxide, iron (III) nitrate, peracetic acid, ammonium peroxodisulfate, iron (III) sulfate, and iron (III) ammonium sulfate.
- hydrogen peroxide is mentioned from the viewpoint that metal ions do not adhere to the surface and are generally used and inexpensive.
- These oxidizing agents may be used alone or in admixture of two or more.
- the content of the oxidizing agent in the polishing liquid composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and further preferably 0.1% by mass or more from the viewpoint of improving the polishing rate. From the viewpoint of reducing the surface roughness of the substrate, it is preferably 4% by mass or less, more preferably 2% by mass or less, and still more preferably 1% by mass or less.
- Another component can be mix
- examples of other components include a heterocyclic aromatic compound, a water-soluble polymer having an anionic group (also referred to as “anionic water-soluble polymer”), an aliphatic amine compound, and an alicyclic ring in one or more embodiments. And formula amine compounds.
- a thickener, a dispersant, a rust inhibitor, a basic substance, a surfactant, and the like can be given.
- the polishing liquid composition for polishing the object to be polished contains a heterocyclic aromatic compound (including a salt thereof).
- the heterocyclic aromatic compound contained in the polishing liquid composition according to the present disclosure is a heterocyclic aromatic compound containing two or more nitrogen atoms in the heterocyclic ring from the viewpoint of scratching the substrate after polishing and reducing particles. It is preferable that it has 3 or more nitrogen atoms in the heterocyclic ring, more preferably 3 or more and 9 or less, still more preferably 3 or more and 5 or less, and even more preferably 3 or 4 .
- the heterocyclic aromatic compound is pyrimidine, pyrazine, pyridazine, 1,2,3-triazine, 1,2,4-triazine, 1,2,5-triazine, 1 from the viewpoint of reducing scratches on the substrate after polishing.
- 1H-benzotriazole 1H-tolyltriazole Is more preferable, and 1H-benzotriazole is still more preferable.
- alkyl group of the alkyl-substituted product include a lower alkyl group having 1 to 4 carbon atoms, and more specifically, a methyl group and an ethyl group.
- amine-substituted product include 1- [N, N-bis (hydroxyethylene) aminomethyl] benzotriazole and 1- [N, N-bis (hydroxyethylene) aminomethyl] tolyltriazole.
- the salt of the heterocyclic aromatic compound is not particularly limited, and specific examples include salts with metals, ammonia, and alkylamines.
- Specific examples of the metal include metals belonging to 1A, 1B, 2A, 2B, 3A, 3B, 4A, 6A, 7A, or Group 8 of the periodic table (long period type). From the viewpoint of reducing scratches, ammonia or a metal belonging to Group 1A is preferable.
- the content of the heterocyclic aromatic compound in the polishing liquid composition is preferably 0.01% by mass or more based on the total mass of the polishing liquid composition from the viewpoint of reducing scratches and particles on the substrate after polishing.
- 0.02% by mass or more is more preferable, 0.05% by mass or more is further preferable, 0.06% by mass or more is further more preferable, 0.07% by mass or more is further more preferable, and 0.08% by mass or more is preferable.
- it is preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 2% by mass or less, still more preferably 1% by mass or less, and even more preferably 0.5% by mass or less.
- 0.3 mass% or less is still more preferable.
- the heterocyclic aromatic compound in the polishing composition may be one kind or two or more kinds.
- the polishing liquid composition for polishing an object to be polished contains an anionic water-soluble polymer from the viewpoint of reducing scratches, particles and maximum surface roughness (AFM-Rmax) of the substrate after polishing. Is preferred.
- the polymer reduces frictional vibration during polishing to prevent the silica agglomerates from dropping from the openings of the polishing pad, and increases the maximum value (AFM-Rmax) of the scratch and surface roughness of the substrate after polishing. It is estimated to decrease.
- anionic group of the anionic water-soluble polymer examples include a carboxylic acid group, a sulfonic acid group, a sulfuric acid ester group, a phosphoric acid ester group, and a phosphonic acid group.
- the maximum value of scratches, particles, and surface roughness From the viewpoint of reducing (AFM-Rmax), those having a carboxylic acid group and / or a sulfonic acid group are more preferred, and those having a sulfonic acid group are more preferred.
- These anionic groups may take the form of neutralized salts.
- the water-soluble polymer having a carboxylic acid group and / or a sulfonic acid group is selected from the group consisting of a structural unit derived from a monomer having a carboxylic acid group and a structural unit derived from a monomer having a sulfonic acid group. Examples thereof include (co) polymers having at least one structural unit or salts thereof. Examples of the monomer having a carboxylic acid group include itaconic acid, (meth) acrylic acid, maleic acid and the like.
- Examples of the monomer having a sulfonic acid group include isoprene sulfonic acid, 2- (meth) acrylamido-2-methylpropane sulfonic acid, styrene sulfonic acid, methallyl sulfonic acid, vinyl sulfonic acid, allyl sulfonic acid, and isoamyl sulfonic acid. Examples thereof include lensulfonic acid and naphthalenesulfonic acid.
- the anionic water-soluble polymer may contain two or more types of structural units derived from a monomer having a carboxylic acid group and structural units derived from a monomer having a sulfonic acid group.
- a copolymer containing a structural unit derived from (meth) acrylic acid and a structural unit derived from a sulfonic acid group-containing monomer (hereinafter, “(Meth) acrylic acid / sulfonic acid copolymer” is also preferred.
- the (meth) acrylic acid / sulfonic acid copolymer is a structural unit derived from a monomer other than the sulfonic acid group-containing monomer and the (meth) acrylic acid monomer within the scope of the effects of the present invention. It may contain components.
- the content of the structural unit derived from the sulfonic acid group-containing monomer in all the structural units constituting each of the (meth) acrylic acid / sulfonic acid copolymer or its salt is 3 mol% from the viewpoint of reducing scratches. Preferably, it is 5 mol% or more, more preferably 8 mol% or more, and it is preferably 97 mol% or less, more preferably 50 mol% or less, still more preferably 30 mol%. % Or less.
- the (meth) acrylic acid monomer containing a sulfonic acid group is counted as a sulfonic acid group-containing monomer.
- the (meth) acrylic acid / sulfonic acid copolymer is a (meth) acrylic acid / 2- (meth) acrylamide-2-methylpropanesulfonic acid copolymer
- (meth) acrylic acid and 2- (meth) acrylamide The molar ratio of polymerization with -2-methylpropanesulfonic acid ((meth) acrylic acid / 2- (meth) acrylamide-2-methylpropanesulfonic acid) is determined from the viewpoint of scratches on the substrate surface after polishing and reduction of particles.
- 95/5 to 40/60 is preferable, 95/5 to 50/50 is more preferable, 95/5 to 60/40 is still more preferable, 95/5 to 70/30 is still more preferable, and 95/5 to 75 / 25 is even more preferred, 95/5 to 80/20 is even more preferred, and 95/5 to 85/15 is even more preferred.
- Preferred (meth) acrylic acid / sulfonic acid copolymers include (meth) acrylic acid / isoprenesulfonic acid copolymers, (meth) acrylic acid / 2- (meth) acrylamide-2-methyl, from the viewpoint of reducing scratches.
- Propanesulfonic acid copolymer, (meth) acrylic acid / isoprenesulfonic acid / 2- (meth) acrylamide-2-methylpropanesulfonic acid copolymer, (meth) acrylic acid / 2- (meth) acrylamide A -2-methylpropanesulfonic acid copolymer is more preferred.
- the counter ion of the water-soluble polymer having an anionic group is not particularly limited, and specific examples include ions of metals, ammonium, alkylammonium and the like.
- Specific examples of the metal include metals belonging to the periodic table (long-period type) 1A, 1B, 2A, 2B, 3A, 3B, 4A, 6A, 7A, or Group 8.
- metals belonging to Group 1A, 3B, or Group 8 are preferable from the viewpoint of surface roughness and scratch reduction, and sodium and potassium belonging to Group 1A are more preferable.
- alkylammonium include tetramethylammonium, tetraethylammonium, tetrabutylammonium and the like.
- these salts ammonium salts, sodium salts, and potassium salts are more preferable.
- the weight average molecular weight of the anionic water-soluble polymer is preferably 500 or more and 100,000 or less, more preferably 500 or more and 50,000 or less, still more preferably 500 or more and 20,000 or less, from the viewpoint of scratch and particle reduction and productivity maintenance. Even more preferably, it is 1000 or more and 10,000 or less, still more preferably 1000 or more and 8000 or less, still more preferably 1000 or more and 5000 or less, still more preferably 1000 or more and 4000 or less, and still more preferably 1000 or more and 3000 or less. Specifically, the weight average molecular weight is measured by the measurement method described in Examples.
- the content of the anionic water-soluble polymer in the polishing composition is preferably 0.001 to 1% by mass, more preferably 0.005 to 0.00%, from the viewpoint of achieving both scratch and particle reduction and productivity. It is 5% by mass, more preferably 0.08 to 0.2% by mass, still more preferably 0.01 to 0.1% by mass, and still more preferably 0.01 to 0.075% by mass.
- the polishing composition for polishing the object to be polished preferably contains an aliphatic amine compound or an alicyclic amine compound from the viewpoint of scratching the substrate surface after polishing and reducing particles.
- the number of nitrogen atoms in the molecule is preferably 2 or more from the viewpoint of scratching the substrate surface after polishing and reducing particles.
- the aliphatic amine compound or the alicyclic amine compound preferably has 4 or less nitrogen atoms, more preferably 3 or less, and more preferably 2 or less from the viewpoint of maintaining the polishing rate. Further preferred. Therefore, the aliphatic amine compound or alicyclic amine compound preferably has 2 to 4 nitrogen atoms in the molecule from the viewpoint of maintaining the polishing rate and reducing scratches and particles. More preferably, two are more preferable.
- Examples of the aliphatic amine compound include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, 1,2-diaminopropane, 1,3-dimethylpropanediamine from the viewpoint of reducing scratches and particles on the substrate surface after polishing.
- Examples of the alicyclic amine compound include piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, 1-amino-4-methylpiperazine, and N-methyl from the viewpoint of reducing scratches and particles on the substrate surface after polishing.
- the aliphatic amine compound or alicyclic amine compound used in the polishing liquid composition is an N-amino compound from the viewpoint of reducing scratches and particles on the substrate surface after polishing, reducing amine odor, and improving solubility in water.
- it is selected from the group consisting of ethylethanolamine, N-aminoethylisopropanolamine, N-aminoethyl-N-methylethanolamine, piperazine, N- (2-aminoethyl) piperazine and hydroxyethylpiperazine, It is even more preferred that it be selected from the group consisting of N-aminoethylethanolamine, N- (2-aminoethyl) piperazine and hydroxyethylpiperazine, and even more preferred is N-aminoethylethanolamine.
- the content of the aliphatic amine compound or alicyclic amine compound in the polishing liquid composition is 0.001 to the mass of the entire polishing liquid composition from the viewpoint of reducing scratches and particles on the substrate surface after polishing. It is preferably 10% by mass, more preferably 0.005 to 5% by mass, further preferably 0.008 to 2% by mass, still more preferably 0.01 to 1% by mass, and 0.01 to 0.5%. The mass% is still more preferred, and 0.01 to 0.1 mass% is even more preferred.
- the aliphatic amine compound or alicyclic amine compound in polishing liquid composition may be one type, and may be two or more types.
- the polishing liquid composition obtained by the method for producing a polishing liquid composition according to the present disclosure is supplied, for example, between a non-woven organic polymer polishing cloth or the like (polishing pad) and a substrate to be polished,
- the polishing composition is supplied to the polishing surface of the substrate sandwiched between polishing plates with a polishing pad, and the polishing step and / or the substrate is moved under a predetermined pressure to perform the polishing process while contacting the substrate. Used.
- this polishing generation of scratches and particles can be remarkably suppressed.
- the present disclosure is a method for polishing a substrate, the polishing liquid composition according to the present disclosure is supplied to a surface to be polished of a substrate to be polished, a polishing pad is brought into contact with the surface to be polished,
- the present invention relates to a method for polishing a substrate including moving and polishing the polishing pad and / or the substrate to be polished.
- the polishing liquid composition is particularly suitable for the production of precision component substrates.
- it is suitable for polishing precision component substrates such as substrates of magnetic recording media such as magnetic disks and magneto-optical disks, optical disks, photomask substrates, optical lenses, optical mirrors, optical prisms, and semiconductor substrates.
- polishing according to the present disclosure in a polishing process of a silicon wafer (bare wafer), a formation process of a buried element isolation film, a planarization process of an interlayer insulating film, a formation process of a buried metal wiring, a buried capacitor formation process, etc.
- the polishing liquid composition obtained by the manufacturing method of a liquid composition can be used.
- the polishing composition according to the present disclosure is particularly effective in the polishing process, but can be similarly applied to other polishing processes such as a lapping process.
- Suitable materials for the polishing object using the polishing composition according to the present disclosure include, for example, metals or metalloids such as silicon, aluminum, nickel, tungsten, copper, tantalum, and titanium, or alloys thereof, glass, and glassy materials.
- metals or metalloids such as silicon, aluminum, nickel, tungsten, copper, tantalum, and titanium, or alloys thereof, glass, and glassy materials.
- glassy substances such as carbon and amorphous carbon, ceramic materials such as alumina, silicon dioxide, silicon nitride, tantalum nitride, and titanium carbide, and resins such as polyimide resins.
- a Ni—P plated aluminum alloy substrate or a glass substrate such as crystallized glass or tempered glass is more suitable
- a Ni—P plated aluminum alloy substrate is more suitable.
- the polishing liquid according to the present disclosure can be applied to a shape having a flat portion such as a disk shape, a plate shape, a slab shape, or a prism shape, or a shape having a curved surface portion such as a lens.
- the composition is used. Among them, it is excellent for polishing a disk-shaped workpiece.
- the present disclosure provides the polishing target surface by supplying the polishing liquid composition obtained by the manufacturing method of the polishing liquid composition according to the present disclosure to the polishing target surface of the substrate to be polished.
- the present invention relates to a method of manufacturing a magnetic disk substrate including a polishing step.
- the present disclosure provides a polishing liquid composition by a method for manufacturing a polishing liquid composition according to the present disclosure, and supplies the polishing liquid composition to a surface to be polished of a substrate to be polished
- the present invention relates to a method for manufacturing a magnetic disk substrate, comprising bringing a polishing pad into contact with a surface to be polished and moving the polishing pad and / or the substrate to be polished to polish the surface to be polished.
- the present disclosure further discloses the following composition, production method, or application.
- ⁇ 1> including a step of subjecting a silica dispersion to be treated containing colloidal silica to a filtration treatment with a filter containing a filter aid,
- the average particle diameter of the primary particles determined by the colloidal silica titration method is 1 nm or more and 50 nm or less,
- the manufacturing method of the polishing liquid composition whose hydroxyl group density of the said filter aid is 0.40 * 10 ⁇ -5 > mol / m ⁇ 2 > or more.
- the average particle size of primary particles obtained by the colloidal silica titration method is preferably 5.0 nm or more, more preferably 10.0 nm or more, still more preferably 12.0 nm or more, preferably 45 nm or less. Yes, More preferably, it is 42 nm or less, More preferably, it is 40 nm or less, The manufacturing method of the polishing liquid composition as described in ⁇ 1>.
- the hydroxyl group density of the filter aid is preferably 0.41 ⁇ 10 ⁇ 5 mol / m 2 or more, more preferably 0.43 ⁇ 10 ⁇ 5 mol / m 2 or more, preferably Is 2.0 ⁇ 10 ⁇ 5 mol / m 2 or less, more preferably 1.5 ⁇ 10 ⁇ 5 mol / m 2 or less, and the method for producing the polishing composition according to ⁇ 1> or ⁇ 2>.
- the filter aid was obtained by deoxidizing the diatomaceous earth after mixing the diatomaceous earth having a hydroxyl group density of less than 0.40 ⁇ 10 ⁇ 5 mol / m 2 and an acid aqueous solution.
- the acid contained in the acid aqueous solution is preferably a group consisting of hydrochloric acid, nitric acid, phosphoric acid, phosphonic acid such as 1-hydroxyethylidene-1,1-diphosphonic acid, phosphinic acid, and an organic acid having a pKa of less than 4.
- Ratio of average particle diameter of primary particles determined by titration method of colloidal silica and average particle diameter measured by laser particle size distribution measuring device of filter aid (average of primary particles by titration method of colloidal silica) is preferably 1.20 ⁇ 10 ⁇ 3 or more, more preferably 1.35 ⁇ 10 ⁇ 3 or more, and even more preferably 1.
- the filter aid CV value is preferably 70% or more, more preferably 75% or more, still more preferably 80% or more, still more preferably 85% or more, preferably 100% or less, more preferably
- the average particle diameter of the filter aid measured by a laser particle size distribution measuring device is preferably 0.5 ⁇ m or more, more preferably 1 ⁇ m or more, still more preferably 4.5 ⁇ m or more, and even more preferably 8 ⁇ m or more.
- it is 10 ⁇ m or more, preferably 100 ⁇ m or less, more preferably 60 ⁇ m or less, still more preferably 50 ⁇ m or less, even more preferably 40 ⁇ m or less, even more preferably 20 ⁇ m or less, and even more preferably 13 ⁇ m or less.
- ⁇ 1>- ⁇ 7> The manufacturing method of the polishing composition in any one of ⁇ 7>.
- the average pore diameter of the filter aid by mercury porosimetry is preferably 0.1 to 3.5 ⁇ m, more preferably 0.1 to 3.0 ⁇ m, still more preferably 0.1 to 2.7 ⁇ m, More preferably, the method for producing a polishing composition according to any one of ⁇ 1> to ⁇ 8>, which is 0.1 to 2.6 ⁇ m.
- the cumulative pore volume of pore size of 0.15 ⁇ m or less by the nitrogen adsorption method of the filter aid is preferably 0.3 mL / g or more, more preferably 0.4 mL / g or more, and still more preferably 0.
- any one of ⁇ 1> to ⁇ 9> which is 6 mL / g or more, preferably 100.0 mL / g or less, more preferably 50.0 mL / g or less, and still more preferably 10.0 mL / g or less.
- the cumulative pore volume of pore size of 0.5 ⁇ m or less by the mercury intrusion method of the filter aid is preferably 2.5 mL / g or more, more preferably 2.7 mL / g or more, and even more preferably 3.0 mL.
- a polishing composition according to any one of ⁇ 1> to ⁇ 10>, further preferably 20 mL / g or less, and even more preferably 10 mL / g or less.
- the content of colloidal silica in the treated silica dispersion is preferably 1% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, and even more preferably 30% by mass or more.
- ⁇ 14> including a step of mixing a silica dispersion obtained by subjecting the silica dispersion to be treated to the filtration treatment to a mixture containing an acid, an oxidizing agent, and water.
- ⁇ 1> to ⁇ 13> The manufacturing method of the polishing liquid composition in any one of.
- the polishing composition according to ⁇ 15> further comprising a water-soluble polymer having an anionic group, a heterocyclic aromatic compound, and an aliphatic amine compound or an alicyclic amine compound.
- the polishing composition obtained by the method for producing a polishing composition according to any one of ⁇ 1> to ⁇ 14> is supplied to the surface to be polished of the substrate to be polished, so that the polishing is performed.
- a polishing liquid composition is manufactured by the manufacturing method of the polishing liquid composition, and the polishing liquid composition is supplied to a surface to be polished of a substrate to be polished, and a polishing pad is brought into contact with the surface to be polished.
- the method for manufacturing a magnetic disk substrate according to ⁇ 17> comprising moving the polishing pad and / or the substrate to be polished to polish the surface to be polished.
- a filter aid comprising diatomaceous earth, preferably 1.5 ⁇ 10 ⁇ 5 mol / m 2 or less.
- colloidal silica slurry a (pH 9.0, manufactured by JGC Catalysts & Chemicals, average particle diameter of primary particles 18.0 nm, silica particle concentration 40% by mass)
- colloidal silica slurry b (pH 10.0, JGC) Made by Catalyst Kasei Co., Ltd., average particle size of primary particles 50.0 nm, silica particle concentration 40% by mass)
- colloidal silica slurry c pH 10.0, manufactured by JGC Catalysts & Chemicals Co., Ltd., average particle size of primary particles 100.0 nm, silica
- the particle concentration was 40% by mass (Table 1).
- the average particle diameter of primary particles of colloidal silica in the silica dispersion to be treated and the polishing composition, and the 0.45 ⁇ m filter liquid flow rate were measured as follows.
- the obtained sample solution is immersed in a constant temperature water bath (20 ⁇ 2 ° C.) for about 30 minutes. Using a potentiometric titrator, titration with a 0.1 mol / L sodium hydroxide standard solution was used, and the amount of sodium hydroxide standard solution used when the pH of the sample solution changed from 4.0 to 9.0.
- Filter aid-containing filters were prepared as described below using the following commercially available filter aids A to C (see Table 2 below).
- Filter aids A to C, and filter aids 1 to 16 obtained by heat treatment or acid treatment of filter aids A to C, laser average particle diameter, CV value, integrated pore volume, hydroxyl group of filter aid
- the density was determined by the following method.
- the above parameters for filter aids A to C are shown in Table 2.
- the laser average particle diameter, CV value, integrated pore volume, and average pore diameter are values for the filter aid before being treated with an acid aqueous solution, respectively.
- the hydroxyl group densities for filter aids A to C and filter aids 1 to 16 are shown in Tables 2 and 4 to 7, respectively.
- the average pore diameter in Table 2 is a catalog value.
- the sample was pretreated by placing the sample in a firing furnace (trade name: SK-2535E, manufactured by Motoyama Co., Ltd.), raising the temperature of the firing furnace to 100 ° C. at 10 ° C./min, and then increasing the temperature to 100 ° C. This was done by holding for 2 hours. Moreover, the inside of a baking furnace was deaerated so that the pressure might be set to 500 micrometers Hg at the time of 60 degreeC.
- a firing furnace trade name: SK-2535E, manufactured by Motoyama Co., Ltd.
- Measurement conditions Measurement cell: Micromeritics 5cc-Powder (08-0444)) Measurement method: Pressure control method (pressure table mode) Low Pressure equribium time 5secs, High pressure equilibrium time 5secs Parameters relating to Hg: contact angle: 130 °, surface tension: 485 dynes / cm Stem Volume Used: Adjust the sample amount to about 50% at 100% or less
- the surface area of the filter aid was measured by a nitrogen adsorption method. Specifically, about 1 g of each filter aid weighed accurately was set in ASAP2020 (manufactured by Shimadzu Corporation, specific surface area / pore distribution measuring device) and obtained from the nitrogen adsorption isotherm by the Halsey method of the BJH method. The obtained value was defined as the surface area.
- Control method of OH group density The OH group density was controlled by performing the following heat treatment or acid treatment on each of the above-mentioned filter aids A to C.
- the filter aid was placed in a baking dish, and the filter aid was fired using a firing furnace (trade name: SK-2535E, manufactured by Motoyama Co., Ltd.). Specifically, the baking dish containing the filter aid is placed in a baking furnace set at a furnace temperature of 25 ° C., and the temperature in the baking furnace is kept for 10 hours while airflow (3 L / min). The temperature was raised to 800 ° C., and the filter aid was baked in an atmosphere at 800 ° C. for 5 hours or 10 hours.
- a firing furnace trade name: SK-2535E, manufactured by Motoyama Co., Ltd.
- filter paper No. 5A (opening 7 ⁇ m): manufactured by Advantech
- ILET90-TL manufactured by Sumitomo 3M
- the aqueous solution was filtered to form a uniform cake layer of filter aid on the filter paper, and then the cake layer was washed with 1-2 L of ion exchange water to obtain a filter containing the filter aid.
- content of the filter aid in a filter aid containing filter was 0.18 g / cm ⁇ 2 >.
- Polishing test machine Speed Fam Co., double-sided 9B polishing machine
- Polishing pad Fujibow Co., urethane finishing polishing pad
- Upper plate rotation speed 32.5 rpm / min
- Polishing liquid composition supply amount 100 mL / Minute / Main polishing time: 4 minutes / Main polishing load: 7.8 kPa ⁇ Number of loaded substrates: 10
- Measurement equipment Optical full-scale defect inspection machine (Candela OSA6100 manufactured by KLA-Tencor) : Atomic force microscope (Veco, DI Nano-Scope III) Measurement method: The polished substrate was immersed in ion-exchanged water for 5 minutes, and then rinsed with ion-exchanged water for 20 seconds. After that, among the substrates put into the polishing tester, four are selected at random, and each substrate rotating at 10000 rpm is irradiated with a laser using an optical whole surface defect inspection machine, and the length is 100 ⁇ m or more. A scratch on the substrate surface was detected.
- scratches having a depth of 1 nm or more and less than 100 nm, a width of 5 nm or more and less than 500 nm were counted as scratches using an atomic force microscope.
- the total number of scratches on each side of the four substrates was divided by 8 to calculate the number of scratches per substrate surface, and are shown in Tables 4-7.
- Example 1 in which the hydroxyl group density of diatomaceous earth is 0.40 ⁇ 10 ⁇ 5 mol / m 2 or more and the average particle diameter of primary particles of colloidal silica is 1 nm or more and 50 nm or less.
- the MF value was higher and the number of scratches was lower than those in Comparative Examples 1-17.
- the present disclosure it is possible to effectively remove coarse particles and gelated substances in the silica dispersion to be treated containing colloidal silica, thereby providing high filtration accuracy and a polished substrate surface. It is possible to produce a polishing composition that can reduce the number of scratches. Therefore, the productivity of a substrate such as a magnetic disk substrate is improved by using the method for producing a polishing composition of the present invention.
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Abstract
Description
本開示にかかる研磨液組成物の製造方法に用いられる濾過助剤としては、一又は複数の実施形態において、珪藻土、シリカ、カオリン、酸性白土、パーライト、ベントナイト、タルク等の不溶性の鉱物性物質が挙げられる。粗大粒子及びゲル化物の低減、及び研磨後の基板表面のスクラッチの低減の観点から、前記濾過助剤のうち、二酸化ケイ素、珪藻土、パーライトが好ましく、珪藻土、パーライトがより好ましく、珪藻土が更に好ましい。
本開示において「濾過助剤の粒径分布のCV値」とは、粒度分布の広がりを表す指標となる数値であって、CV値(%)=標準偏差/平均粒径 の式で求められる値をいう。一又は複数の実施形態において、CV値は、濾過助剤をレーザ回折/散乱式粒度分布計で測定して得られた算術標準偏差を体積基準のメジアン径として得られた値で割った値の割合(%)として求められ、本開示においては、検出角90°におけるMarquardt法によって得られる散乱強度分布の測定により算出される値とした。具体的には実施例に記載の方法により求めることができる。
本開示において、濾過助剤の「レーザ平均粒子径」とは、レーザ式粒度分布測定装置により測定される濾過助剤の平均粒子径であり、本開示においては、検出角90°におけるMarquardt法によって得られる散乱強度分布の測定により算出される値とした。濾過助剤のレーザ平均粒子径は、実施例に記載の方法により測定することができる。
前記濾過助剤の水銀圧入法による平均細孔径は、スクラッチ及びパーティクルの低減の観点並びに研磨液組成物の生産性向上の観点から、好ましくは0.1~3.5μm、より好ましくは0.1~3.0μm、更に好ましくは0.1~2.7μm、更により好ましくは0.1~2.6μmである。尚、本発明において「水銀圧入法による平均細孔径」とは、濾過助剤粒子の容積基準の細孔径の平均値である。
被処理シリカ分散液のコロイダルシリカの滴定法によって求めた一次粒子の平均粒子径と濾過助剤のレーザ平均粒子径の比(コロイダルシリカの一次粒子の平均粒子径/濾過助剤のレーザ平均粒子径)(以下、「シリカ/濾過助剤の平均粒径比」ともいう。)は、粗大粒子及びゲル化物の低減、及び研磨後の基板表面のスクラッチの低減の観点から、1.20×10-3以上が好ましく、1.35×10-3以上がより好ましく、1.40×10-3以上が更に好ましく、1.42×10-3以上が更により好ましい。また、シリカ/濾過助剤の平均粒径比は、同様の観点から、4.20×10-3以下が好ましく、3.80×10-3以下がより好ましく、3.00×10-3以下が更に好ましく、2.50×10-3以下が更により好ましく、2.00×10-3以下が更により好ましく、1.50×10-3以下が更により好ましい。
濾過助剤の窒素吸着法による細孔径0.15μm以下の積算細孔容積は、スクラッチ及びパーティクルの低減の観点から、好ましくは0.3mL/g以上であり、より好ましくは0.4mL/g以上、更に好ましくは0.6mL/g以上である。また、前記積算細孔容積は、研磨液組成物の生産性向上の観点から、好ましくは100.0mL/g以下、より好ましくは50.0mL/g以下、更に好ましくは10.0mL/g以下である。尚、濾過助剤の0.15μm以下の積算細孔容積は、実施例に記載の方法により測定することがで
きる。
前記濾過助剤の水銀圧入法による細孔径0.5μm以下の積算細孔容積は、スクラッチ及びパーティクルの低減の観点から、好ましくは2.5mL/g以上、より好ましくは2.7mL/g以上、更に好ましくは3.0mL/g以上、更により好ましくは4.0mL/g以上、更により好ましくは4.5mL/g以上である。また、研磨液組成物の生産性向上の観点からは、前記濾過助剤の水銀圧入法による細孔径0.5μm以下の積算細孔容積は、好ましくは1000mL/g以下、より好ましくは100mL/g以下、更に好ましくは50mL/g以下、更により好ましくは20mL/g以下、更により好ましくは10mL/g以下である。尚、濾過助剤の「水銀圧入法による0.5μm以下の積算細孔容積」とは、水銀圧入法による濾過助剤粒子の容積基準の細孔分布における0.5μm以下の細孔容積の総和であり、実施例に記載の方法により測定することができる。
本開示において「被処理シリカ分散液」は、濾過助剤含有フィルタによる濾過処理に供される前のシリカスラリー(シリカ分散液)をいう。被処理シリカ分散液は、一又は複数の実施形態において、コロイダルシリカと水とからなるもの、更に他の成分を含むもの、又は、汎用コロイダルシリカのスラリーが挙げられる。被処理シリカ分散液は、その他の実施形態において、後述の研磨液組成物に配合され得る他の成分を混合して製造されたものが挙げられる。被処理シリカ分散液の状態としては、コロイダルシリカが分散した状態が好ましい。
被処理シリカ分散液のコロイダルシリカの一次粒子の平均粒子径は、特に言及の無い場合、滴定法によって求められた一次粒子の平均粒子径をいう。滴定法による一次粒子の平均粒子径の測定は、具体的には次に記載の通りである。まず、コロイダルシリカスラリーに水を加えて混合液を得る。次に、電位差滴定装置を用いて、塩酸標準溶液等で前記混合液のpHを調整する(例えば3.0)。次に、pH調整された混合液に塩化ナトリウムと水とを混合して、塩化ナトリウムを溶解させ、得られた試料液を恒温水槽内に十分に浸漬させる。次いで、電位差滴定装置を用いて、標準溶液(水酸化ナトリウム溶液等)で滴定を行う。試料液のpHが4.0から9.0まで変化するときに使用された標準溶液の溶質量(g)(A)を読み取り、試料液にコロイダルシリカスラリーを入れない場合の滴定に要した標準溶液の溶質量(g)(B)も読み取る。そして、下記計算式により平均粒子径(nm)を算出する。
平均粒子径(nm)=3100÷26.5×(A-B)÷試料採取量(コロイダルシリカ固形分量)(g)
化物の低減、及び研磨後の基板表面のスクラッチの低減の観点から、1.0nm以上50nm以下であるが、同様の観点から、より好ましくは5.0nm以上、更に好ましくは10.0nm以上、更により好ましくは12.0nm以上であり、好ましくは45nm以下、より好ましくは42nm以下、更に好ましくは40nm以下である。一又は複数の実施形態において、本開示における被処理シリカ分散液、研磨液組成物は、上述の範囲の一次粒子の平均粒子径のコロイダルシリカを含有するものをいう。
本開示にかかる研磨液組成物の製造方法に用いられる濾過助剤含有フィルタは、前記濾過助剤をフィルタ表面及び/又はフィルタ内部に含有するものであれば特に制限されない。本開示にかかる研磨液組成物の製造方法において、例えば、プレコートに更にボディーフィードを組み合わせて用いてもよい。JIS3801に規定された方法によって測定されるフィルタ目開きは、濾過助剤の漏れを防ぐ観点から、15μm以下が好ましく、より好ましくは12μm以下、更に好ましくは10μm以下、更により好ましくは8μm以下である。また、フィルタ通液速度向上の観点から、フィルタ目開きは、0.5μm以上が好ましく、更に好ましくは1.0μm以上、更により好ましくは3.0μm以上、更により好ましくは5.0μm以上である。ここでプレコートとは、ケーク濾過フィルタの形成方法であり、後述のフィルタ材料(ろ紙等の基材)の上に厚さ数mm程度の濾過助剤の薄い層を形成することである。例えば、水に濾過助剤粒子を分散させ、濾材で濾過助剤をこしとり濾過助剤層を形成する手法が挙げられる。又、ボディーフィードとは、濾過の際にケーク濾過される原液に濾過助剤を一定量投入しながら濾過処理する方法であり、目的は、原液の濾過性の改善である。粒径が細かくすぐにケーク抵抗が極大化する(濾過ができなくなる)ような原液に対して有効である。
本開示にかかる研磨液組成物又はシリカ分散液の製造方法において、濾過助剤含有フィルタで濾過処理する工程の条件のうちの濾過圧は、粗大粒子及びゲル化物の低減、及び研磨後の基板表面のスクラッチの低減の観点から、0.16MPa以上が好ましく、より好ましくは0.18MPa以上、更に好ましくは0.20MPa以上である。濾過処理工程の濾過圧力は、同様の観点から、0.49MPa以下が好ましく、より好ましくは0.45MPa以下、更に好ましくは0.40MPa以下、更により好ましくは0.30MPa以下である。尚、本開示において「濾過圧力」とは、濾過助剤に掛かる単位面積当たりの圧力であって、一又は複数の実施形態において、レギュレーターで出力圧力を調整することにより調節できる。
粗大粒子やゲル化物が多い研磨液組成物又はシリカ分散液(濾過処理された被処理シリカ分散液)をフィルタに通液した時、目詰まりを起こし通液量が低下する。従って、研磨液組成物/シリカ分散液の0.45μmフィルタ通液量(孔径0.45μmのフィルタに対する通液量)は、粗大粒子やゲル化物の存在量の尺度となる。なお、シリカ粒子の一次粒子の平均粒子径が大きい場合も目詰まりを起こしやすく0.45μmフィルタ通液量は低下するので、「0.45μmフィルタ通液量」は、シリカ粒子の一次粒子の平均粒子径が同程度の研磨液組成物/シリカ分散液を比較するためのパラメータとして適している。
上述した濾過処理方法により、粗大粒子及びゲル化物が低減したシリカ分散液を得ることができる。したがって、本開示は、その他の態様において、コロイダルシリカを含有する被処理シリカ分散液を濾過助剤を含むフィルタで濾過処理する工程を含み、前記コロイダルシリカの滴定法によって求められる一次粒子の平均粒子径が1nm以上50nm以下であり、前記濾過助剤の水酸基密度が0.40×10-5mol/m2以上である、シリカ分散液の製造方法に関する。該製造方法により得られるシリカ分散液は、一又は複数の実施形態において、後述する本開示にかかる、濾過精度の高い研磨液組成物を製造することができ、また、研磨後の基板表面のスクラッチが低減された基板を製造することができる。
本開示は、その他の態様において、研磨液組成物の製造方法で製造される又はされ得る研磨液組成物(以下「本開示にかかる研磨液組成物」ともいう。)に関する。本開示にかかる研磨液組成物は、一又は複数の実施形態において、コロイダルシリカ及び水に加え、後述する酸若しくはその塩又はアルカリ、及び/又は酸化剤を含む形態が挙げられる。但し、本開示にかかる研磨液組成物はこれらの組成に限定されず、他の成分を含んでもよい。本開示にかかる研磨液組成物は、一又は複数の実施形態において、本開示にかかるシリカ分散液の製造方法で得られたシリカ分散液に必要に応じてその他の成分を混合することで得られる研磨液組成物である。
被研磨物を研磨する際の本開示にかかる研磨液組成物中のコロイダルシリカの含有量は、研磨速度を向上させる観点から、好ましくは0.5質量%以上、より好ましくは1質量%以上、更に好ましくは2質量%以上、更に好ましくは4質量%以上、また、経済的に表面品質を向上させる観点から、好ましくは20質量%以下、より好ましくは15質量%以下、更に好ましくは13質量%以下、更により好ましくは10質量%以下、更により好ましくは8質量%以下である。
本開示にかかる研磨液組成物に使用される水としては、イオン交換水、蒸留水、超純水等が挙げられる。本開示にかかる研磨液組成物中の水の含有量は、100質量%から研磨材及び他の成分を除いた残部に相当し、60~99質量%が好ましく、80~97質量%がより好ましい。
本開示にかかる研磨液組成物の25℃におけるpHは、研磨対象によって適宜調節すればよいが、0.1以上7.0以下が好ましい。アルカリ性においては、酸性に比べてスクラッチが発生しやすい傾向にある。その発生機構は明らかではないが、研磨粒子同士が表面電荷によって強く反発し合うアルカリ性雰囲気下では、研磨液組成物中に含有される研磨材の一次粒子の凝集物あるいは粗大粒子が、被研磨物と研摩パッドとの間で研摩材が密に充填されることを妨げるため、荷重が研磨面全面に対して不均一に加わるものと推定される。pHは、被研磨物の種類や要求特性に応じて決定することが好ましく、被研磨物の材質が金属材料では、研磨速度を向上させる観点から、より好ましくは6.0以下、更に好ましくは5.0以下、更により好ましくは4.0以下、更により好ましくは3.0以下、更により好ましくは2.0以下である。また、人体への影響を低減する観点及び研磨装置の腐食を防止する観点から、pHは、より好ましくは0.5以上、更に好ましくは0.7以上、更により好ましくは0.9以上、更により好ましくは1.0以上、更により好ましくは1.2以上である。特に、ニッケル-リン(Ni-P)メッキされたアルミニウム合金基板のように被研磨物の材質が金属材料であり、被研磨物が精密部品用基板である場合は、研磨速度を向上させる観点、人体への影響を低減する観点、及び研磨装置の腐食を防止する観点から、pHは、0.5以上6.0以下がより好ましく、更に好ましくは0.7以上5.0以下、更により好ましくは0.9以上4.0以下、更により好ましくは1.0以上3.0以下、更により好ましくは1.0以上2.0以下である。
本開示にかかる研磨液組成物は、研磨速度向上の観点から、酸又はその塩を含んでもよい。前記酸及びその塩としては、具体的には、硝酸、硫酸、亜硝酸、過硫酸、塩酸、過塩素酸、リン酸、ホスホン酸、ホスフィン酸、ピロリン酸、トリポリリン酸、アミド硫酸等の無機酸又はそれらの塩、2-アミノエチルホスホン酸、1-ヒドロキシエチリデン-1,1-ジホスホン酸、ヒドロキシホスホノ酢酸(PHAA)、アミノトリ(メチレンホスホン酸)、エチレンジアミンテトラ(メチレンホスホン酸)、ジエチレントリアミンペンタ(メチレンホスホン酸)、エタン-1,1-ジホスホン酸、エタン-1,1,2-トリホスホン酸、エタン-1-ヒドロキシ-1,1-ジホスホン酸、エタン-1-ヒドロキシ-1,1,2-トリホスホン酸、エタン-1,2-ジカルボキシ-1,2-ジホスホン酸、メタンヒドロキシホスホン酸、2-ホスホノブタン-1,2-ジカルボン酸、2-ホスホノ-1,2,4-ブタントリカルボン酸(PBTC)、1-ホスホノブタン-2,3,4-トリカルボン酸、α-メチルホスホノコハク酸等の有機ホスホン酸又はそれらの塩、グルタミン酸、ピコリン酸、アスパラギン酸等のアミノカルボン酸又はそれらの塩、シュウ酸、ニトロ酢酸、マレイン酸、オキサロ酢酸等のカルボン酸又はそれらの塩などが挙げられる。これらは単独で又は2種類以上を混合して用いてもよい。中でもスクラッチを低減する観点から、本開示にかかる研磨液組成物は、無機酸又は有機ホスホン酸及びそれらの塩を含むことが好ましい。
本開示にかかる研磨液組成物は、研磨速度向上の観点から、酸化剤を含有することが好ましい。本開示にかかる研磨液組成物に使用できる酸化剤としては、研磨速度を向上させる観点から、過酸化物、過マンガン酸又はその塩、クロム酸又はその塩、ペルオキソ酸又はその塩、酸素酸又はその塩、金属塩類、硝酸類、硫酸類等が挙げられる。
また、前記研磨液組成物には、必要に応じて他の成分を配合することができる。他の成分としては、一又は複数の実施形態において、複素環芳香族化合物、アニオン性基を有する水溶性高分子(「アニオン性水溶性高分子」とも呼ぶ。)、脂肪族アミン化合物、脂環式アミン化合物等が挙げられる。また、更にその他の成分として、一又は複数の実施形態において、増粘剤、分散剤、防錆剤、塩基性物質、界面活性剤等が挙げられる。
被研磨物を研磨する際の研磨液組成物は複素環芳香族化合物(その塩も含む)を含有することが好ましい。本開示にかかる研磨液組成物に含有される複素環芳香族化合物は、研磨後の基板のスクラッチ及びパーティクルの低減の観点から、複素環内に窒素原子を2個以上含む複素環芳香族化合物であることが好ましく、複素環内に窒素原子を3個以上有することがより好ましく、3個以上9個以下が更に好ましく、3個以上5個以下が更により好ましく、3又は4個が更により好ましい。
被研磨物を研磨する際の研磨液組成物は、研磨後の基板のスクラッチ、パーティクル及び表面粗さの最大値(AFM‐Rmax)の低減の観点から、アニオン性水溶性高分子を含有することが好ましい。該高分子は、研磨時の摩擦振動を低減して研磨パッドの開孔部からのシリカ凝集体の脱落を防止し、研磨後の基板のスクラッチ及び表面粗さの最大値(AFM‐Rmax)を低減するものと推定される。
被研磨物を研磨する際の研磨液組成物は、研磨後の基板表面のスクラッチ及びパーティクルの低減の観点から、脂肪族アミン化合物又は脂環式アミン化合物を含有することが好ましい。前記脂肪族アミン化合物又は脂環式アミン化合物について、研磨後の基板表面のスクラッチ及びパーティクルの低減の観点から、分子内の窒素原子数は2個以上であることが好ましい。また、前記脂肪族アミン化合物又は脂環式アミン化合物は、研磨速度の維持の観点から、分子内の窒素原子数は4個以下であることが好ましく、3個以下がより好ましく、2個以下が更に好ましい。したがって、前記脂肪族アミン化合物又は脂環式アミン化合物は、研磨速度の維持、並びにスクラッチ及びパーティクルの低減の観点から、分子内の窒素原子数は2~4個であることが好ましく、2~3個がより好ましく、2個が更に好ましい。
本開示にかかる研磨液組成物の製造方法にて得られた研磨液組成物は、例えば、不織布の有機高分子系研磨布等(研磨パッド)と被研磨基板との間に供給され、即ち、研磨液組成物が、研磨パッドを貼り付けた研磨盤で挟み込まれた基板研磨面に供給され、所定の圧力の下で研磨盤及び/又は基板を動かすことにより、基板に接触しながら研磨工程に用いられる。この研磨によりスクラッチ及びパーティクルの発生を顕著に抑えることができる。したがって、本開示は、その他の態様において、基板の研磨方法であって、本開示にかかる研磨液組成物を被研磨基板の研磨対象面に供給し、前記研磨対象面に研磨パッドを接触させ、前記研磨パッド及び/又は前記被研磨基板を動かして研磨することを含む基板の研磨方法に関する。
したがって、本開示は、その他の態様において、本開示にかかる研磨液組成物の製造方法によって得られた研磨液組成物を、被研磨基板の研磨対象面に供給することにより、前記研磨対象面を研磨する工程を含む、磁気ディスク基板の製造方法に関する。また、本開示は、その他の態様において、本開示にかかる研磨液組成物の製造方法によって研磨液組成物を製造すること及び前記研磨液組成物を被研磨基板の研磨対象面に供給し、前記研磨対象面に研磨パッドを接触させ、前記研磨パッド及び/又は前記被研磨基板を動かして、前記研磨対象面を研磨することを含む、磁気ディスク基板の製造方法に関する。
前記コロイダルシリカの滴定法によって求められる一次粒子の平均粒子径が1nm以上50nm以下であり、
前記濾過助剤の水酸基密度が0.40×10-5mol/m2以上である、研磨液組成物の製造方法。
<2> 前記コロイダルシリカの滴定法によって求められる一次粒子の平均粒子径が、好ましくは5.0nm以上、より好ましくは10.0nm以上、更に好ましくは12.0nm以上であり、好ましくは45nm以下であり、より好ましくは42nm以下であり、更に好ましくは40nm以下である、<1>に記載の研磨液組成物の製造方法。
<3>前記濾過助剤、好ましくは珪藻土の水酸基密度が、好ましくは0.41×10-5mol/m2以上、より好ましくは0.43×10-5mol/m2以上であり、好ましくは2.0×10-5mol/m2以下、より好ましくは1.5×10-5mol/m2以下である、<1>又は<2>に記載の研磨液組成物の製造方法。
<4> 前記濾過助剤は、前記水酸基密度が0.40×10-5mol/m2未満の珪藻土と酸水溶液とを混合した後、前記珪藻土に対して脱酸処理をすることによって得た、<1>~<3>のいずれかに記載の研磨液組成物の製造方法。
<5>前記酸水溶液に含まれる酸が、好ましくは塩酸、硝酸、リン酸、1-ヒドロキシエチリデン-1,1-ジホスホン酸等のホスホン酸、ホスフィン酸、pKaが4未満の有機酸からなる群から選ばれる少なくとも1種、より好ましくは塩酸、硝酸、リン酸、ホスホン酸、ホスフィン酸、及びpKa3.5未満の有機酸からなる群から選ばれる少なくとも1種、更に好ましくは硝酸、リン酸、ホスホン酸、ホスフィン酸、及びpKa3.1以下の有機酸からなる群から選ばれる少なくとも1種、更により好ましくはホスホン酸、及びホスフィン酸からなる群から選ばれる少なくとも1種である、<4>に記載の研磨液組成物の製造方法。
<6> 前記コロイダルシリカの滴定法によって求められる一次粒子の平均粒子径と前記濾過助剤のレーザ式粒度分布測定装置により測定される平均粒子径の比(コロイダルシリカの滴定法による一次粒子の平均粒子径/濾過助剤のレーザ式粒度分布測定装置により測定される平均粒子径)が、好ましくは1.20×10-3以上、より好ましくは1.35×10-3以上、更に好ましくは1.40×10-3以上、更により好ましくは1.42×10-3以上であり、好ましくは4.20×10-3以下、より好ましくは3.80×10-3以下、更に好ましくは3.00×10-3以下、更により好ましくは2.50×10-3以下、更により好ましくは2.00×10-3以下、更により好ましくは1.50×10-3以下である、<1>~<5>のいずれかに記載の研磨液組成物の製造方法。
<7>前記濾過助剤CV値が、好ましくは70%以上、より好ましくは75%以上、更に好ましくは80%以上、更により好ましくは85%以上であり、好ましくは100%以下、より好ましくは99%以下である、<1>~<6>のいずれかに記載の研磨液組成物の製造方法。
<8> 前記濾過助剤のレーザ式粒度分布測定装置により測定される平均粒子径が、好ましくは0.5μm以上、より好ましくは1μm以上、更に好ましくは4.5μm以上、更により好ましくは8μm以上、更により好ましくは10μm以上であり、好ましくは100μm以下、より好ましくは60μm以下、更に好ましくは50μm以下、更により好ましくは40μm以下、更により好ましくは20μm以下、更により好ましくは13μm以下である、<1>~<7>のいずれかに記載の研磨液組成物の製造方法。
<9> 前記濾過助剤の水銀圧入法による平均細孔径は、好ましくは0.1~3.5μm、より好ましくは0.1~3.0μm、更に好ましくは0.1~2.7μm、更により好ましくは0.1~2.6μmである、<1>~<8>のいずれかに記載の研磨液組成物の製造方法。
<10> 前記濾過助剤の窒素吸着法による細孔径0.15μm以下の積算細孔容積が、好ましくは0.3mL/g以上であり、より好ましくは0.4mL/g以上、更に好ましくは0.6mL/g以上であり、好ましくは100.0mL/g以下、より好ましくは50.0mL/g以下、更に好ましくは10.0mL/g以下である、<1>~<9>のいずれかに記載の研磨液組成物の製造方法。
<11> 前記濾過助剤の水銀圧入法による細孔径0.5μm以下の積算細孔容積が、好ましくは2.5mL/g以上、より好ましくは2.7mL/g以上、更に好ましくは3.0mL/g以上、更により好ましくは4.0mL/g以上、更により好ましくは4.5mL/g以上であり、好ましくは1000mL/g以下、より好ましくは100mL/g以下、更に好ましくは50mL/g以下、更により好ましくは20mL/g以下、更により好ましくは10mL/g以下である、<1>~<10>のいずれかに記載の研磨液組成物の製造方法。
<12> 前記被処理シリカ分散液中のコロイダルシリカの含有量が、好ましくは1質量%以上、より好ましくは10質量%以上、更に好ましくは20質量%以上、更により好ましくは30質量%以上であり、好ましくは50質量%以下、より好ましくは45質量%以下、更に好ましくは43質量%以下、更により好ましくは40質量%以下である、<1>~<11>のいずれかに記載の研磨液組成物の製造方法。
<13> 前記被処理シリカ分散液の25℃におけるpHが、好ましくは8.5以上、より好ましくは8.8以上、更に好ましくは9.0以上であり、好ましくは11以下、より好ましくは10.8以下、更に好ましくは10.5以下である、<1>~<12>のいずれかに記載の研磨液組成物の製造方法。
<14> 酸と酸化剤と水とを含む混合液に、前記被処理シリカ分散液に前記濾過処理を施すことによって得られたシリカ分散液を混合する工程を含む、<1>~<13>のいずれかに記載の研磨液組成物の製造方法。
<15> <1>~<14>のいずれかの項に記載の研磨液組成物の製造方法により製造される研磨液組成物。
<16> 更に、アニオン性基を有する水溶性高分子と、複素環芳香族化合物と、脂肪族アミン化合物又は脂環式アミン化合物と、を含有する<15>に記載の研磨液組成物。
<17> <1>~<14>のいずれかの項に記載の研磨液組成物の製造方法により得られた研磨液組成物を、被研磨基板の研磨対象面に供給することにより、前記研磨対象面を研磨する工程を含む、磁気ディスク基板の製造方法。
<18> 前記研磨液組成物の製造方法により研磨液組成物を製造すること、及び、前記研磨液組成物を被研磨基板の研磨対象面に供給し、前記研磨対象面に研磨パッドを接触させ、前記研磨パッド及び/又は前記被研磨基板を動かして、前記研磨対象面を研磨することを含む、前記<17>に記載の磁気ディスク基板の製造方法。
<19> <1>~<14>のいずれかの項に記載の研磨液組成物の製造方法に用いられる濾過助剤であって、水酸基密度が0.40×10-5mol/m2以上、好ましくは0.41×10-5mol/m2以上、より好ましくは0.43×10-5mol/m2以上であり、好ましくは2.0×10-5mol/m2以下、より好ましくは1.5×10-5mol/m2以下である珪藻土を含む濾過助剤。
<20> 前記<19>に記載の濾過助剤の製造方法であって、
水酸基密度が0.40×10-5mol/m2未満の珪藻土と酸水溶液とを混合した後、前記珪藻土に対して脱酸処理をする工程を含む、濾過助剤の製造方法。
被処理シリカ分散液として、コロイダルシリカスラリーa(pH9.0、日揮触媒化成社製、一次粒子の平均粒径18.0nm、シリカ粒子濃度40質量%)、コロイダルシリカスラリーb(pH10.0、日揮触媒化成社製、一次粒子の平均粒径50.0nm、シリカ粒子濃度40質量%)、及びコロイダルシリカスラリーc(pH10.0、日揮触媒化成社製、一次粒子の平均粒径100.0nm、シリカ粒子濃度40質量%)を用いた(表1)。被処理シリカ分散液及び研磨液組成物におけるコロイダルシリカの一次粒子の平均粒子径、0.45μmフィルタ通液量は、以下のように測定した。
まず、コロイダルシリカスラリーを固形分で1.5g分を200mLビーカーに採取し、イオン交換水100mLを加えてこれらをスターラーで混合し混合液を得る。次に、電位差滴定装置を用いて、0.1mol/Lの塩酸標準溶液で混合液のpHを3.0に調整する。pH調製された混合液に、塩化ナトリウム30.0gを加えスターラーで溶解し、さらにビーカーの150mLの標線までイオン交換水を加えスターラーで混合する。得られた試料液を恒温水槽(20±2℃)に約30分間浸漬する。電位差滴定装置を用いて、0.1mol/Lの水酸化ナトリウム標準溶液で滴定をおこない、試料液のpHが4.0から9.0まで変化するときに使用された水酸化ナトリウム標準溶液の量(g)(A)を読み取る。一方で、コロイダルシリカスラリーを200mLビーカーに入れないで空試験をおこない、空試験の滴定に要した水酸化ナトリウム標準溶液の量(g)(B)を読み取る。そして、下記計算式により平均粒子径(nm)を算出する。
平均粒子径(nm)=3100÷26.5×(A-B)÷試料採取量(g)
試料採取量:コロイダルシリカスラリー固形分1.5g
下記市販の濾過助剤A~C(下記表2参照)を用いて下記の通り濾過助剤含有フィルタを作製した。濾過助剤A~Cおよび、濾過助剤A~Cに対して熱処理又は酸処理して得た濾過助剤1~16のレーザ平均粒子径、CV値、積算細孔容積、濾過助剤の水酸基密度については下記の方法で求めた。濾過助剤A~Cについての上記のパラメータは表2に示した。濾過助剤1~16についての上記のパラメータのうち、レーザ平均粒子径、CV値、積算細孔容積、平均細孔径については、各々、酸水溶液等により処理される前の濾過助剤についての値と同じであった。濾過助剤A~C、及び濾過助剤1~16についての水酸基密度については、表2、表4~表7に各々示した。表2中の平均細孔径はカタログ値である。
各濾過助剤について、レーザ回折/散乱式粒度分布計(商品名LA-920、堀場製作所製)で測定して得られた体積基準のメジアン径として得られた値をレーザ平均粒子径とした。
各濾過助剤をレーザ回折/散乱式粒度分布計(商品名LA-920、堀場製作所製)で測定して得られた算術標準偏差を体積基準のメジアン径として得られた値で割った値の割合をCV値(%)とした。
濾過助剤の細孔径0.15μm以下の積算細孔容積は、窒素吸着法により測定した。具体的には、精秤した約1gの各濾過助剤をASAP2020(株式会社島津製作所社製、比表面積・細孔分布測定装置)にセットし、窒素吸着等温線からBJH法のHalsey式により求めた細孔径が0.15μm以下の細孔容積の総和を、0.15μm以下の積算細孔容積とした。なお、試料の前処理は、試料を焼成炉(株式会社モトヤマ製、商品名:SK-2535E)内に入れ、焼成炉の温度を10℃/分で100℃まで昇温させ、その後100℃を2時間保持することにより行った。また、60℃の時点で焼成炉内をその圧力が500μmHgになるように脱気した。
各濾過助剤を天秤で約0.1~0.3g精秤し、これを、ヘキサンでよく洗浄した5cc粉末用測定セルにステム内やスリ部に付着させないように入れ、AutoPoreIV-9500(島津製作所社製 水銀圧入法 細孔分布測定装置)にセルをセットした。次に、パソコンでアプリケーション(AutoPoreIV-9500 ver1.07)を立上げ、Sample Information(先に測定した濾過助剤の重量)、Analysis Condition(Standardを選択)、Penetrometer Property(セル重量)、Report condition(Standardを選択)に必要事項をInputし、測定を行った。低圧部、高圧部の順に測定を行い、自動的にMedian Pore Diameter (Volume)(μm)と各Pore Size Diameter(μm)に対するLog Differencial Pore Volume(mL/g)の結果を得た。
測定セル:Micromeritics社製 5cc-Powder(08-0444))
測定方式:圧力制御方式(圧力テーブルモード)
Low Pressure equlibrium time 5secs、
High pressure equilibrium time 5secs
Hgに関するパラメータ:接触角:130°、表面張力:485dynes/cm
Stem Volume Used:100%以下で約50%にサンプル量を調整
0.5μm以下のLog Differencial Pore Volume(mL/g)の値を積算して細孔径が0.5μm以下の積算細孔容積とした。
下記測定法で得られた1gあたりの水酸基数を下記測定法で得られた1gあたりの濾過助剤の表面積で割った値を、濾過助剤の水酸基密度とした。
・電位差測定装置:京都電子社製、電位差自動滴定装置「AT-310J」
・滴定試薬:0.01N塩酸水溶液
・滴定試薬の滴下速度:0.03ml/分
・測定試料:0.2重量%の濾過助剤濃度となるようにNaOH水溶液で希釈したものを測定試料として用いた。
濾過助剤の表面積は、窒素吸着法により測定した。具体的には、精秤した約1gの各濾過助剤をASAP2020(株式会社島津製作所社製、比表面積・細孔分布測定装置)にセットし、窒素吸着等温線からBJH法のHalsey式により得られた値を表面積とした。
下記に示す熱処理、又は酸処理を上記記載の上記A~Cの各濾過助剤に対して行うことにより、OH基密度の制御を行なった。
濾過助剤を焼成皿に入れ、焼成炉(株式会社モトヤマ製、商品名:SK-2535E)を用いて濾過助剤を焼成した。具体的には、濾過助剤が入った焼成皿を、炉内の温度が25℃に設定された焼成炉内に入れ、エアーフロー(3L/min)しながら焼成炉内の温度を10時間かけて800℃まで昇温し、更に800℃の雰囲気下で5時間又は10時間、濾過助剤の焼成を行った。
各濾過助剤50gに、下記表3に示す酸水溶液(a~t)150mlを加え、十分に撹拌・混合した。撹拌を止めて表3に記載の時間(処理時間)静置した後、上澄みを除去した。上澄みが除去された混合液にイオン交換水を加えてスターラーで5分間撹拌し、上澄みが透明になるまで静置した後、上澄み液を除去して、濾過助剤を洗浄した。この操作を上澄みが中性(pH=5~8)になるまで繰り返した。最後に濾過助剤をろ紙上に濾過して自然乾燥させ、酸処理された濾過助剤を得た。
前記酸処理した濾過助剤10gに100mLのイオン交換水を加え、撹拌・混合し濾過助剤分散水溶液を得た。次に、90mmφの平板型SUS製ハウジング(住友3M社製INLET90-TL)にろ紙(No.5A(目開き7μm):アドバンテック社製)をセットし、0.1MPa以下の圧力で濾過助剤分散水溶液を濾過してろ紙上に濾過助剤の均一なケーク層を形成させた後、ケーク層を1~2Lのイオン交換水で洗浄し、濾過助剤を含有するフィルタを得た。なお、濾過助剤含有フィルタにおける濾過助剤の含有量は、0.18g/cm2であった。
〔被処理シリカ分散液の濾過条件:実施例1~18及び比較例1~17〕
作製した濾過助剤含有フィルタを乾燥させずに洗浄水で濡れたままの状態で、濾過圧0.30MPa、濾過流量34.6g/(分・m2)で、被処理シリカ分散液(コロイダルシリカスラリーa~c)をろ過し、研磨液組成物に使用するためのシリカ分散液を得た。尚、シリカ分散液の25℃におけpHは、表4~表7に示した。
上記濾過により得られたシリカ分散液を所定のフィルタ(アドバンテック社製 親水性PTFE0.45(孔径)μmフィルタ、型式:25HP045AN、)で、エアー圧力0.25MPaの一定圧力の下でフィルタに通液させ、フィルタが閉塞するまでの通液量(ml)をMF値として求め、表4~表7に示した。尚、本条件による0.45μmフィルタ通液量は、該シリカ分散液を研磨液組成物の調製に使用した場合にスクラッチを低減することができることの指標とすることができる。すなわち、MF値が高いほど、スクラッチの低減が可能なシリカ分散液又は研磨液組成物と評価することができる。
イオン交換水に、1H-ベンゾトリアゾールNa塩を0.1質量%、N-アミノエチルエタノールアミンを0.03質量%、アクリル酸/アクリルアミド-2-メチルプロパンスルホン酸共重合体ナトリウム塩(アニオン性高分子、モル比90/10、重量平均分子量2000、東亞合成社製)を0.02質量%、硫酸を0.4質量%、1-ヒドロキシエチリデン-1,1-ジホスホン酸を0.05質量%、過酸化水素を0.4質量%添加、混合した水溶液の撹拌下に、前記濾過助剤を含有するフィルタでろ過したろ過済みシリカ分散液を研磨液組成物中のシリカ濃度が5質量%になるように添加して、実施例1~18及び比較例1~17の研磨液組成物を調製した(pH1.0~2.0(25℃))。
アニオン性高分子の重量平均分子量は、下記測定条件におけるゲルパーミエーションクロマトグラフィー(GPC)法により測定した。
(GPC条件)
カラム:TSKgel G4000PWXL+TSKgel G2500PWXL(東ソー製)
ガードカラム:TSKguardcolumn PWXL(東ソー製)
溶離液:0.2Mリン酸バッファー/CH3CN=9/1(体積比)
温度:40℃
流速:1.0mL/分
試料サイズ:5mg/mL
検出器:RI
換算標準:ポリアクリル酸Na(分子量(Mp):11.5万、2.8万、4100、1250(創和科学及びAmerican Polymer Standards Corp.製))
上記のように調製した実施例1~18及び比較例1~17の研磨液組成物を用いて、下記の条件で仕上げ研磨を行った。それぞれの研磨後の基板のスクラッチ数を評価し、その結果を下記表4~表7に示した。被研磨基板として、アルミナ研磨材を含有する研磨液であらかじめ粗研磨し、AFM-Raが5~15Å、厚さ1.27mmの外径95mmφで内径25mmφのNi-Pメッキアルミニウム合金基板を用いた。
・研磨試験機:スピードファム社製、両面9B研磨機
・研磨パッド:フジボウ社製、ウレタン製仕上げ研磨用パッド
・上定盤回転数:32.5rpm/分
・研磨液組成物供給量:100mL/分
・本研磨時間:4分
・本研磨荷重:7.8kPa
・投入した基板の枚数:10枚
・測定機器:光学式全面欠陥検査機(KLA-Tencor社製Candela OSA6100)
:原子間力顕微鏡(Veco社社製、DI Nano-Scope III)
・測定方法:研磨を行った基板をイオン交換水中に5分間浸漬した後、イオン交換水で20秒間すすぎを行った。その後、研磨試験機に投入した基板のうち、無作為に4枚を選択し、光学式全面欠陥検査機を用いて10000rpmに回転中の各基板にレーザを照射して、長さが100μm以上の基板表面の傷を検出した。また、これらのスクラッチのうち、原子間力顕微鏡を用いて、深さが1nm以上、100nm未満、幅が5nm以上、500nm未満の傷をスクラッチとしてカウントした。4枚の基板の各々両面にあるスクラッチ数(本)の合計を8で除して、基板面当たりのスクラッチ数を算出し、表4~表7に示した。
Claims (10)
- コロイダルシリカを含有する被処理シリカ分散液を、濾過助剤を含むフィルタで濾過処理する工程含み、
前記コロイダルシリカの滴定法によって求められる一次粒子の平均粒子径が1nm以上50nm以下であり、
前記濾過助剤の水酸基密度が0.40×10-5mol/m2以上である、研磨液組成物の製造方法。 - 前記濾過助剤は、前記水酸基密度が0.40×10-5mol/m2未満の珪藻土と酸水溶液とを混合した後、前記珪藻土に対して脱酸処理をすることによって得た、請求項1に記載の研磨液組成物の製造方法。
- 前記コロイダルシリカの滴定法によって求められる一次粒子の平均粒子径と前記濾過助剤のレーザ式粒度分布測定装置により測定される平均粒子径の比(コロイダルシリカの滴定法による一次粒子の平均粒子径/濾過助剤のレーザ式粒度分布測定装置により測定される平均粒子径)が、1.20×10-3以上4.20×10-3以下である、請求項1又は2に記載の研磨液組成物の製造方法。
- 酸と酸化剤と水とを含む混合液に、前記被処理シリカ分散液に前記濾過処理を施すことによって得られたシリカ分散液を混合する工程を含む、請求項1又は2に記載の研磨液組成物の製造方法。
- 請求項1~4のいずれかの項に記載の研磨液組成物の製造方法により製造される研磨液組成物。
- 更に、アニオン性基を有する水溶性高分子と、複素環芳香族化合物と、脂肪族アミン化合物又は脂環式アミン化合物と、を含有する請求項5に記載の研磨液組成物。
- 請求項1~4のいずれかの項に記載の研磨液組成物の製造方法により得られた研磨液組成物を、被研磨基板の研磨対象面に供給することにより、前記研磨対象面を研磨する工程を含む、磁気ディスク基板の製造方法。
- 前記研磨液組成物の製造方法により研磨液組成物を製造すること、及び、
前記研磨液組成物を前記被研磨基板の前記研磨対象面に供給し、前記研磨対象面に研磨パッドを接触させ、前記研磨パッド及び/又は前記被研磨基板を動かして、前記研磨対象面を研磨することを含む、請求項7に記載の磁気ディスク基板の製造方法。 - 請求項1~4のいずれかの項に記載の研磨液組成物の製造方法に用いられる濾過助剤であって、
水酸基密度が0.40×10-5mol/m2以上の珪藻土を含む濾過助剤。 - 請求項9に記載の濾過助剤の製造方法であって、
水酸基密度が0.40×10-5mol/m2未満の珪藻土と酸水溶液とを混合した後、前記珪藻土に対して脱酸処理をする工程を含む、濾過助剤の製造方法。
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JP7066480B2 (ja) | 2018-03-29 | 2022-05-13 | 株式会社フジミインコーポレーテッド | 砥粒分散液、研磨用組成物キットおよび磁気ディスク基板の研磨方法 |
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