JP6092623B2 - Manufacturing method of magnetic disk substrate - Google Patents

Description

  The present disclosure relates to a method for manufacturing a magnetic disk substrate and a method for polishing a magnetic disk substrate.

  In recent years, magnetic disk drives have been reduced in size and capacity, and high recording density has been demanded. Therefore, it is necessary to improve the detection sensitivity of high recording density magnetic signals, and technical development is underway to reduce the flying height of the magnetic head and reduce the unit recording area. The magnetic disk substrate is designed to improve the smoothness and flatness (reduction of surface roughness, waviness and edge sag) and to reduce surface defects (residual abrasive grains and scratches) in order to reduce the flying height of the magnetic head and ensure the recording area. , Reduction of protrusions, pits, etc.) is strictly demanded.

  From the viewpoint of achieving both improvement in surface quality and productivity, such as smoother and less scratches, such a requirement, the hard disk substrate manufacturing method includes a multi-stage polishing method having two or more polishing steps. Often adopted. In general, in the final polishing step of the multi-stage polishing method, that is, the final polishing step, a polishing composition for finishing that contains colloidal silica particles in order to satisfy the requirements of reducing surface roughness and scratches such as scratches, protrusions, and pits. In the polishing step (also referred to as rough polishing step) prior to the final polishing step, a polishing liquid composition containing alumina particles is used from the viewpoint of improving productivity (for example, Patent Document 1).

  When alumina particles are used as abrasive grains, media scratches may be caused by texture scratches caused by the piercing of alumina particles to the substrate. In order to solve such a problem, a polishing liquid composition containing alumina particles having a specific particle size and silica particles having a specific particle size distribution in a rough polishing process has been proposed (for example, Patent Document 2).

  In addition, as a technique for further reducing the piercing of alumina particles to the substrate, (1) a step of polishing with a polishing composition A containing alumina particles and water, (2) a substrate obtained in step (1) A step of rinsing, (3) supplying a polishing composition B containing silica particles and water to the surface to be polished of the substrate obtained in step (2), and moving the polishing pad and / or the substrate to be polished. A method of manufacturing a magnetic disk substrate has been proposed in which the step of polishing the surface to be polished is performed with the same polishing machine, and the final polishing step is performed with a polishing machine different from the polishing machine (for example, Patent Document 3). .

  However, as long as alumina is used, the piercing of alumina particles to the substrate does not become zero. Therefore, recently, without using alumina abrasive grains in the rough polishing step, pulverized silica abrasive grains using the first polishing disk A method for producing a substrate for a magnetic recording medium, comprising: a rough polishing step of polishing while supplying a polishing solution containing a liquid; and a final polishing step of polishing while supplying a polishing solution containing colloidal silica abrasive grains using a second polishing disk Has been proposed (for example, Patent Document 4).

  On the other hand, studies have been made on controlling the shape of silica particles as means for improving the polishing rate of silica particles that are generally lower in polishing rate than alumina particles (for example, Patent Documents 5 to 7).

  In addition, a polishing liquid composition containing a polishing accelerator and a method for producing a memory hard disk using the same are proposed for the purpose of compensating for the low polishing rate of silica particles (for example, Patent Documents 8 and 9).

JP 2005-63530 A JP 2009-176597 A JP 2011-204327 A JP 2012-155785 A JP 2009-91197 A JP 2010-192904 A JP 2008-13655 A JP 2001-288456 A JP 2001-11433 A

  As the capacity of magnetic disk drives is increased, the required characteristics for the surface quality of the substrate are becoming stricter, and it is possible to further reduce the residue of the abrasive grains used in the rough polishing process (for example, alumina adhesion, alumina sticking). There is a need for development of polishing liquid compositions. As a means to reduce the piercing of abrasive grains derived from the rough polishing process, the use of pulverized silica abrasive grains can greatly reduce the piercing of the abrasive grains, but it has not been achieved yet and cannot be completely reduced to zero. (For example, Patent Document 4).

  In order to eliminate the piercing of abrasive grains derived from the rough polishing step, it is desirable to use silica particles produced by only the particle growth method without using the pulverization step and having no crushing surface and difficult to pierce as an alumina substitute. Since the cutting force is weaker than that of pulverized abrasive grains, it has been found that the polishing rate is insufficient, and in addition, it is difficult to reduce long wavelength waviness.

  Therefore, the present disclosure can reduce long-wave waviness after the rough polishing process without impairing the productivity without using alumina particles in the rough polishing process, and to the substrate after the final polishing process than when alumina particles are used. The present invention provides a method of manufacturing a magnetic disk substrate that can significantly reduce residual abrasive grains (protrusion defects).

In one aspect, the present invention relates to a method for manufacturing a magnetic disk substrate having the following steps (1) to (3) (hereinafter also referred to as “substrate manufacturing method of the present disclosure”).
(1) A polishing liquid composition A containing silica particles A, an acid, an oxidizing agent, and water is supplied to the surface to be polished of the substrate to be polished, and the polishing pad is brought into contact with the surface to be polished, and the polishing pad and / or Alternatively, a step of polishing the surface to be polished by moving the substrate to be polished.
(2) A step of cleaning the substrate obtained in step (1).
(3) A polishing liquid composition B containing silica particles B and water is supplied to the polishing target surface of the substrate obtained in step (2), and the polishing pad is brought into contact with the polishing target surface, and the polishing pad and / or Alternatively, a step of polishing the surface to be polished by moving the substrate to be polished.
The steps (1) and (3) are performed by another polishing machine.
In addition, the silica particles A have a ΔCV value of 10.0% or more and 30.0% or less, and a non-spherical silica a having an average particle diameter (D1) of 50.0 nm or more and 125.0 nm or less, or a ΔCV value. Is non-spherical silica b having an average particle size (D1) of 120.0 nm or more and 300.0 nm or less.
The oxidizing agent is at least one selected from the group consisting of hydrogen peroxide, peroxodisulfate, periodic acid and salts thereof.
And when it does not contain periodic acid or its salt as the oxidizing agent, iron sulfate, iron nitrate, ammonium sulfate iron, iron perchlorate, iron chloride, iron citrate, ammonium iron citrate, iron oxalate, oxalic acid It contains at least one oxidation promoting aid selected from the group consisting of iron chelate complexes of ammonium iron and ethylenediaminetetraacetic acid.
Here, the ΔCV value is obtained by dividing the standard deviation based on the scattering intensity distribution at a detection angle of 30 ° by the dynamic light scattering method by the average particle diameter based on the scattering intensity distribution and multiplying by 100 (CV30). Of the standard deviation based on the scattering intensity distribution at a detection angle of 90 ° by the dynamic light scattering method divided by the average particle diameter based on the scattering intensity distribution and multiplied by 100 (ΔCV = CV30−CV90) The average particle diameter (D1) is an average particle diameter based on a scattering intensity distribution at a detection angle of 90 ° by a dynamic light scattering method.

  In one aspect, the present invention relates to a method for polishing a magnetic disk substrate (hereinafter, also referred to as “polishing method of the present disclosure”) having the steps (1) to (3) above. The present invention relates to a polishing system that performs the steps (3) to (3).

  The substrate manufacturing method of the present disclosure can significantly reduce the protrusion defects after rough polishing and after final polishing without using alumina particles. In addition, according to the substrate manufacturing method of the present disclosure, it is possible to express a high polishing rate at a level that can be actually produced as a rough polishing step using silica particles, and to reduce long-wave waviness after the rough polishing step. As a result, it is possible to produce an effect that a magnetic disk substrate with improved substrate quality can be manufactured with high productivity.

FIG. 1 is an example of an electron microscope (TEM) observation photograph of abrasive grains A (non-spherical silica a) represented by silica particles A. FIG. 2 is an example of an electron microscope (TEM) observation photograph of abrasive grains G (non-spherical silica b) typified by silica particles A. FIG. 3 is an example of an electron microscope (TEM) observation photograph of abrasive grains s represented by silica particles B.

  According to the present disclosure, if a rough polishing process and a final polishing process that do not use alumina particles are employed in a polishing process of a magnetic disk substrate, residual alumina (for example, alumina adhesion, alumina sticking) can be eliminated, thereby reducing protrusion defects. Based on this knowledge. However, when the rough polishing step is performed with a polishing composition comprising silica particles produced by the particle growth method as an alternative to alumina, the polishing rate is significantly reduced, and long wavelength waviness after rough polishing and after final polishing. Gets worse. Therefore, in order to reduce the long wavelength waviness in the rough polishing process, the polishing time must be significantly extended beyond a predetermined value, and there is a problem that productivity is lowered. The present disclosure solves the above problem by performing a rough polishing step using a polishing composition containing non-spherical silica particles defined by predetermined parameters, an acid, a specific oxidizing agent, and an oxidation promoting aid. Based on the knowledge that it can. That is, according to the present disclosure, even when alumina particles are not substantially included, a high polishing rate can be obtained in the rough polishing step, so that long wavelength waviness after rough polishing can be reduced without reducing productivity. The problem can be solved.

  By the substrate manufacturing method of the present disclosure, it is possible to reduce long-wave waviness and protrusion defects after rough polishing while maintaining a high polishing rate necessary for the rough polishing step without using alumina. The reason why the wavelength waviness and the protrusion defect can be reduced is not necessarily clear, but is estimated as follows. Consider the case of polishing a Ni-P plated aluminum alloy substrate as a substrate to be polished. When polishing is performed by supplying the polishing liquid composition to the surface to be polished of the substrate to be polished, the polishing liquid composition is simultaneously etched on the surface of the substrate to be polished with chemical components such as acid and oxidant contained in the polishing liquid composition. Polishing proceeds by performing mechanical cutting with the abrasive grains contained in. If the balance between the etching by the chemical component and the mechanical cutting by the abrasive grains is good, the polishing proceeds efficiently, the polishing rate is improved, and the waviness is likely to be reduced. In particular, since the long-wave waviness is a wave-length waviness component (about 500 to 5000 μm), it can be estimated that the deeper the cutting depth of the substrate to be polished by the abrasive grains, the more efficiently it is reduced. Therefore, even if the cutting force of the abrasive grains is improved by using non-spherical silica particles as abrasive grains, if the etching by chemical components is insufficient, the cutting depth to the substrate to be polished will not be so deep, so long wavelength waviness is Difficult to reduce. On the contrary, even if the etching is greatly improved by using a polishing accelerating aid, etc., if abrasive grains with low cutting force are used, the surface of the substrate to be polished becomes rough due to excessive etching and the long wavelength waviness deteriorates. Resulting in. On the other hand, when specific non-spherical silica particles are used as abrasive grains and a specific polishing acceleration aid is used, there is a synergistic effect between the high cutting force of the non-spherical silica particles and the etching power of the specific polishing acceleration aid. Can be done. The non-spherical silica particles of the present disclosure are considered to have a structure in which a plurality of unit particles are aggregated to form deformed particles, but the non-spherical silica particles defined by the average particle diameter and the ΔCV value are non-spherical silica particles. Since the convex portion of the spherical silica particles has a structure portion that is arranged in a plane with respect to the surface of the substrate to be polished, and when one non-spherical silica particle moves on the substrate to be polished, the substrate is polished with a plurality of contacts, Excellent polishing efficiency and high polishing rate are obtained. Also, since there are multiple contacts with a single particle at very close intervals, uneven polishing is unlikely to occur and long wavelength waviness is reduced. . Further, since the degree of irregularity of the non-spherical silica particles of the present disclosure is not an extreme degree of irregularity such as a mold shape or a wedge shape, it is considered that sticking and remaining on the substrate hardly occur and projection defects are also reduced. Accordingly, the synergistic effect of appropriate etching with the special structure of the non-spherical silica particles and the chemical component of the present disclosure can provide a high polishing rate at a level that can be practically produced as a rough polishing step in the silica particles. It is estimated that long-wave waviness and protrusion defects after rough polishing, as well as long-wave waviness and protrusion defects after finish polishing can be efficiently reduced by maintaining a high level of balance between etching by abrasive and mechanical cutting by abrasive grains. ing. However, the present disclosure need not be construed as being limited to these mechanisms.

  In general, a magnetic disk is manufactured through a recording part forming process by polishing a glass substrate that has undergone a fine grinding process or an aluminum alloy substrate that has undergone a Ni-P plating process through a rough polishing process and a final polishing process. In addition, a rinsing step and a cleaning step may be included between the polishing steps.

  In the present disclosure, “undulation” of the substrate refers to irregularities on the surface of the substrate having a wavelength longer than the roughness. In the present disclosure, “long wavelength undulation” refers to undulation observed with a wavelength of 500 to 5000 μm. By reducing the waviness of the substrate surface after polishing, the flying height of the magnetic head can be reduced, and the recording density of the magnetic disk substrate can be improved. The long wavelength waviness of the substrate surface can be measured using, for example, the measuring device described in the examples.

  In the present disclosure, the “protrusion defect” mainly refers to a defect on the surface of the substrate that is considered to be derived from residual abrasive grains, abrasive grain adhesion, and abrasive grain sticking after the rough polishing process and after final polishing. The protrusion defect on the substrate surface can be evaluated by a surface defect inspection apparatus such as microscopic observation or scanning electron microscope observation of the substrate surface obtained after polishing, and can be specifically evaluated by the method described in the examples. .

[Method of manufacturing magnetic disk substrate]
In general, a magnetic disk is made by polishing a glass substrate that has undergone a fine grinding process or an aluminum alloy substrate that has undergone a Ni-P plating process in a rough polishing process and a final polishing process, and then converted into a magnetic disk in a recording part forming process. Manufactured by. In one aspect, the present disclosure relates to a method for manufacturing a magnetic disk substrate having the following steps (1) to (3).
(1) A polishing liquid composition A containing silica particles A and water 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, and the polishing pad and / or the substrate to be polished is Moving and polishing the surface to be polished.
(2) A step of cleaning the substrate obtained in step (1).
(3) A polishing liquid composition B containing silica particles B and water is supplied to the polishing target surface of the substrate obtained in step (2), and the polishing pad is brought into contact with the polishing target surface, and the polishing pad and / or Alternatively, a step of polishing the surface to be polished by moving the substrate to be polished.

[Step (1): Rough polishing step]
In the step (1), a polishing liquid composition A containing silica particles A and water is supplied to the surface to be polished of the substrate to be polished, the polishing pad is brought into contact with the surface to be polished, and the polishing pad and / or the substrate to be polished is supplied. In this step, the polishing substrate is moved to polish the surface to be polished. The polishing machine used in the step (1) is not particularly limited, and a known polishing machine for polishing a magnetic disk substrate can be used.

[Step (1): Substrate to be polished]
The substrate to be polished in step (1) is a magnetic disk substrate or a substrate used for a magnetic disk substrate. For example, a Ni-P plated aluminum alloy substrate, silicate glass, aluminosilicate glass, crystallization Examples thereof include glass substrates such as glass and tempered glass. Especially, as a to-be-polished substrate used by this indication, the aluminum alloy substrate by which Ni-P plating was carried out is preferred. There is no restriction | limiting in particular in the shape of the said to-be-polished substrate, For example, what is necessary is just the shape which has planar parts, such as a disk shape, plate shape, slab shape, prism shape, and the shape which has curved surface parts, such as a lens. Of these, a disk-shaped substrate to be polished is suitable. In the case of a disk-shaped substrate to be polished, the outer diameter is, for example, about 2 to 95 mm, and the thickness is, for example, about 0.5 to 2 mm.

[Step (1): Polishing liquid composition A]
In the present disclosure, the polishing liquid composition A is a polishing liquid composition used for the rough polishing in the step (1). The polishing composition A contains silica particles A as abrasive grains from the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness after rough polishing, and reducing protrusion defects, and from the viewpoint of improving the polishing rate in rough polishing. It contains an acid, contains an oxidizing agent from the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and contains water as a medium. Moreover, it is preferable that the polishing liquid composition A does not contain an alumina abrasive grain. In the present disclosure, “not containing alumina abrasive grains” means that, in one or a plurality of embodiments, it does not contain alumina particles, does not substantially contain alumina particles, and contains alumina particles in an amount that functions as abrasive grains. The absence of an amount of alumina particles that affect the polishing results. The specific content of alumina particles is not particularly limited, but is preferably 5% by mass or less, more preferably 2% by mass or less, still more preferably 1% by mass or less, and substantially 0%. Is even more preferred.

[Step (1): Silica Particle A]
From the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after finish polishing, the polishing liquid composition A is silica particles A as abrasive grains. Containing. In one or more embodiments, the silica particles contained in the polishing composition A are referred to as silica particles A. Examples of the silica of the silica particles A include colloidal silica, fumed silica, and surface-modified silica. Colloidal silica is preferable from the viewpoints of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after finish polishing. Silica particles A are non-spherical particles, and include the following two embodiments: non-spherical silica a and b.

(Non-spherical silica a)
The non-spherical silica a which is one embodiment of the silica particles is non-spherical silica having a ΔCV value of 10.0% or more and 30.0% or less and an average particle diameter (D1) of 50 nm or more and 125 nm or less. From the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after finish polishing, the ΔCV value of non-spherical silica a is 10.0% or more. More preferably, it is 11.0% or more, more preferably 12.0% or more, and even more preferably 15.0% or more. From the same viewpoint, the ΔCV value is preferably 30.0% or less, more Preferably it is 28.0% or less, More preferably, it is 25.0% or less, More preferably, it is 22.3% or less.

  The average particle diameter (D1) of the non-spherical silica a is 50 from the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after final polishing. 0.0 nm or more is preferable, more preferably 60.0 nm or more, further preferably 80.0 nm or more. From the same viewpoint, the average particle diameter (D1) is preferably 125.0 nm or less, more preferably 123.0 nm or less. More preferably, it is 115.0 nm or less.

  From the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after final polishing, the CV90 of non-spherical silica a is 10.0% or more. Preferably, it is 12.0% or more, more preferably 15.0% or more, even more preferably 20.0% or more, even more preferably 25.0% or more, even more preferably 30.0% or more. From the same viewpoint, CV90 is preferably 40.0% or less, more preferably 39.0% or less.

  The shape of the non-spherical silica a is non-spherical from the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after final polishing. In the present disclosure, the silica particles are non-spherical. In one or more embodiments that are not limited, the ratio of the average particle diameter (D1) determined by the dynamic light scattering method to the specific surface area converted particle diameter (D2) determined by the BET method. (D1 / D2) is 1.50 or more and 4.00 or less. From the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after final polishing, the average particle size of non-spherical silica a by the dynamic light scattering method The ratio (D1 / D2) of the diameter (D1) to the specific surface area converted particle diameter (D2) by the BET method is preferably 1.30 or more, more preferably 1.50 or more, and further preferably 1.70 or more. In view of the above, the ratio (D1 / D2) of the average particle diameter (D1) by the dynamic light scattering method and the specific surface area equivalent particle diameter (D2) by the BET method is preferably 4.00 or less, more preferably 3.00 or less. More preferably, it is 2.50 or less, and still more preferably 2.05 or less.

(Non-spherical silica b)
The non-spherical silica b which is one embodiment of the silica particles is non-spherical silica having a ΔCV value of 0.0% or more and less than 10.0% and an average particle diameter (D1) of 120.0 nm or more and 300.0 nm or less. is there. The ΔCV value of the non-spherical silica b is preferably 0.0% or more, more preferably 0.5% or more, still more preferably 1.0% or more, from the viewpoint of improving the polishing rate in rough polishing. From the viewpoint, it is preferably less than 10.0%, more preferably 8.0% or less, and still more preferably 6.0% or less. In addition, the ΔCV value of the non-spherical silica b is preferably 0.0% or more, more preferably from the viewpoint of reducing long-wave waviness and protrusion defects after rough polishing and reducing long-wave waviness and protrusion defects after finish polishing. Is 0.5% or more, more preferably 1.0% or more, even more preferably 5.0% or more, and even more preferably 6.0% or more. From the same viewpoint, it is preferably less than 10.0% More preferably, it is 9.0% or less, More preferably, it is 8.0% or less.

  The average particle diameter (D1) of the non-spherical silica b is preferably 120.0 nm or more, more preferably 130.0 nm or more, still more preferably 150.0 nm or more, and even more preferably, from the viewpoint of improving the polishing rate in rough polishing. Is 170.0 nm or more, and more preferably 190.0 nm or more. From the same viewpoint, it is preferably 300.0 nm or less, more preferably 260.0 nm or less, still more preferably 220.0 nm or less. In addition, the average particle diameter (D1) of the non-spherical silica b is preferably 120.0 nm or more from the viewpoint of reducing long-wave waviness and protrusion defects after rough polishing and reducing long-wave waviness and protrusion defects after finish polishing. More preferably, it is 121.0 nm or more, more preferably 122.0 nm or more. From the same viewpoint, it is preferably 300.0 nm or less, more preferably 250.0 nm or less, still more preferably 200.0 nm or less, and even more preferably Is 150.0 nm or more, and more preferably 135.0 nm or more.

  The CV90 of the non-spherical silica b is preferably 20.0% or more, more preferably 20.5% or more, and further preferably 21.0% or more from the viewpoint of improving the polishing rate in the rough polishing. Therefore, it is preferably 35.0% or less, more preferably 33.0% or less, still more preferably 25.0% or less, and even more preferably 23.0% or less. Further, the CV90 of the non-spherical silica b is preferably 20.0% or more, more preferably 20.0% or more from the viewpoint of reduction of long-wave waviness and protrusion defects after rough polishing and reduction of long-wave waviness and protrusion defects after finish polishing. 21.0% or more, more preferably 25.0% or more, and from the same viewpoint, 35.0% or less is preferable, more preferably 33.0% or less, still more preferably 30.0% or less, and even more Preferably it is 28.0% or less.

  The shape of the non-spherical silica b is non-spherical from the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after final polishing. In the present disclosure, non-spherical means that, in one or a plurality of embodiments, the ratio (D1 / D2) of the average particle diameter (D1) by the dynamic light scattering method and the specific surface area converted particle diameter (D2) by the BET method Is 1.50 or more and 4.00 or less. The ratio (D1 / D2) of the average particle size (D1) of the non-spherical silica b by the dynamic light scattering method and the specific surface area equivalent particle size (D2) by the BET method is 1 from the viewpoint of improving the polishing rate in the rough polishing. .50 or more, more preferably 2.00 or more, still more preferably 2.50 or more, even more preferably 3.00 or more, still more preferably 3.50 or more. From the same viewpoint, 4.00 The following is preferable, more preferably 3.90 or less, and still more preferably 3.80 or less. Further, the ratio (D1 / D2) of the average particle diameter (D1) of the non-spherical silica b by the dynamic light scattering method and the specific surface area converted particle diameter (D2) by the BET method is long wavelength waviness and protrusion defects after rough polishing. And 1.50 or more are preferable, more preferably 1.80 or more, still more preferably 2.00 or more, and even more preferably 2.40 or more, from the viewpoints of reducing the long-wave undulation and protrusion defects after finish polishing. From the same viewpoint, it is preferably 4.00 or less, more preferably 3.80 or less, still more preferably 3.50 or less, still more preferably 2.90 or less, and even more preferably 2.70 or less. .

[ΔCV value of silica particle A]
In the present disclosure, the ΔCV value of the silica particle A is the standard deviation of the particle diameter measured based on the scattering intensity distribution at the detection angle of 30 ° (forward scattering) by the dynamic light scattering method, and the detection angle of 30 ° by the dynamic light scattering. The coefficient of variation (CV30) multiplied by 100 divided by the average particle size measured based on the scattering intensity distribution (CV30) and the scattering intensity at a detection angle of 90 ° (side scattering) by the dynamic light scattering method The value of the coefficient of variation (CV) multiplied by 100 by dividing the standard deviation of the particle size measured based on the distribution by the average particle size measured based on the scattering intensity distribution at a detection angle of 90 ° by dynamic light scattering ( CV90) is a difference (ΔCV = CV30−CV90), which is a value indicating the angular dependence of the scattering intensity distribution measured by the dynamic light scattering method. The ΔCV value can be specifically measured by the method described in the actual examples.

  The present inventor, as a method of showing the characteristics of non-spherical silica, the average particle size (D1) described above, the average particle size (D1) measured by the dynamic light scattering method and the specific surface area converted particle size (BET method) It was thought that the polishing performance of the silica particles could not be expressed only by the conventional view expressed using the ratio (D1 / D2) to D2). According to further studies by the present inventor, the ΔCV value is effective as a means for knowing the state of the entire system (bulk) of non-spherical silica. By paying attention to these parameters, the polishing rate that has not been known in the past can be obtained. It was found that the range of non-spherical silica capable of reducing the long wavelength waviness and protrusion defects can be accurately defined.

Here, whether the particles in the particle dispersion sample are spherical or non-spherical is generally determined by a method using the angle dependency of the diffusion coefficient (D = Γ / q ² ) measured by the dynamic light scattering method as an index (for example, Jpn. Pat. Appln. KOKAI Publication No. 10-195152). Specifically, the smaller the angle dependency shown in the graph plotting Γ / q ² with respect to the scattering vector q ^{2, the} more the average shape of the particles in the dispersion is judged to be spherical, and the angle dependency is The larger the particle size, the more the average shape of the particles in the dispersion is judged to be non-spherical. In other words, the conventional method using the angular dependence of the diffusion coefficient measured by dynamic light scattering as an index detects the shape and particle size of particles assuming that uniform particles are dispersed throughout the system.・ This is a measurement method. Therefore, the scattering intensity distribution of dynamic light scattering in the dilution system of the polishing composition in which non-spherical silica is dispersed varies greatly depending on the detection angle. The lower the detection angle, the broader the scattering intensity distribution. The measurement result of the scattering intensity distribution of dynamic light scattering depends on the detection angle, and the ΔCV value, which is one of the indicators of “angle dependence of the scattering intensity distribution measured by the dynamic light scattering method”, is measured. By doing so, it is considered that the average shape and particle size of the entire system in the non-spherical silica particle dispersion can be estimated. Note that the present disclosure is not limited to these mechanisms.

[Scattering intensity distribution]
In this disclosure, “scattering intensity distribution” means three particle size distributions (scattering) of sub-micron or less particles determined by dynamic light scattering (DLS) or quasielastic light scattering (QLS). The particle size distribution of the scattering intensity among the intensity, volume conversion, and number conversion. Normally, particles of submicron or less have a Brownian motion in a solvent, and when irradiated with laser light, the intensity of scattered light changes (fluctuates) with time. The fluctuation of the scattered light intensity is calculated by, for example, calculating the autocorrelation coefficient (D) using the photon correlation method (JIS Z 8826), and further using the Einstein-Stokes equation to calculate the average particle size (d: fluid dynamics). Target diameter) can be obtained. In addition to polydispersity index (Polydispersity Index, PI) by cumulant method, particle size distribution analysis includes histogram method (Marquardt method), Laplace inverse transformation method (CONTIN method), non-negative least square method (NNLS method), etc. There is.

In the particle size distribution analysis of the dynamic light scattering method, a polydispersity index (PI) by the cumulant method is generally widely used. However, in the detection method that enables detection of non-spherical particles present in the particle dispersion, the average particle size (d50) is determined from the particle size distribution analysis by the histogram method (Marquardt method) or the Laplace inverse transform method (CONTIN method). D1) and the standard deviation are calculated, a CV value (Coefficient of variation: a numerical value obtained by dividing the standard deviation by the average particle diameter and multiplied by 100) is calculated, and its angular dependence (ΔCV value) is preferably used.
(Reference material)
Text of the 12th Scattering Study Group (held on November 22, 2000) Scattering Basic Course "Dynamic Light Scattering Method" (Mitsuhiro Shibayama, University of Tokyo)
Text of the 20th Scattering Study Group (held on December 4, 2008) Measurement of size distribution of nanoparticles by dynamic light scattering (Doshisha University Yasumori Mori)

[Angle dependence of scattering intensity distribution]
In this disclosure, “angle dependency of the scattering intensity distribution of the particle dispersion” means the scattering intensity according to the scattering angle when the scattering intensity distribution of the particle dispersion is measured at a different detection angle by the dynamic light scattering method. The size of the distribution fluctuation. For example, if the difference in the scattering intensity distribution between the detection angle of 30 ° and the detection angle of 90 ° is large, it can be said that the angle dependency of the scattering intensity distribution of the particle dispersion is large. Therefore, in the present disclosure, measurement of the angle dependence of the scattered intensity distribution includes determining a difference (ΔCV value) between measured values based on the scattered intensity distribution measured at two different detection angles.

  As a combination of two detection angles used for measuring the angle dependency of the scattering intensity distribution, a combination of forward scattering and side or back scattering is preferable from the viewpoint of improving the accuracy of detection of non-spherical particles. From the same viewpoint, the forward scattering detection angle is preferably 0 to 80 °, more preferably 0 to 60 °, still more preferably 10 to 50 °, and still more preferably 20 to 40 °. From the same viewpoint, the side or backscattering detection angle is preferably 80 to 180 °, more preferably 85 to 175 °. In the present disclosure, 30 ° and 90 ° are used as two detection angles for obtaining the ΔCV value.

  The ΔCV value of the silica particles A is an average particle diameter (D1) from the viewpoints of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after final polishing. ) Is 50.0 nm or more and 125.0 nm or less, 10% or more and 30% or less, or when the average particle diameter (D1) is 120.0 nm or more and 300.0 nm or less, 0% or more and less than 10%. A range is preferred. In general, when comparing particles having the same average particle diameter, the ΔCV value becomes a larger value if the degree of deformation is large, and the larger the particle diameter, the larger the particle shape, the particle size factor contributes to the deformation. It is considered that the amount of change in the ΔCV value becomes smaller with respect to the change in the degree of the. Therefore, the non-spherical silica (non-spherical silica a) showing the former range has a relatively small average particle diameter (D1), and has a structure in which several unit particles are aggregated as shown in FIG. Many large non-spherical silicas are believed to be present in the overall system. On the other hand, the non-spherical silica (non-spherical silica b) showing the latter range has a relatively large average particle diameter (D1), and a plurality of unit particles slightly larger than the former non-spherical silica particles as observed in FIG. It is considered that a large amount of agglomerated non-spherical silica is present in the whole system as a whole although the degree of deformation is somewhat large. Therefore, each particle has a structure portion in which the convex portions of the non-spherical silica particles of the present disclosure are arranged in a plane with respect to the surface of the substrate to be polished, and the non-spherical silica particles of the present disclosure and the surface of the substrate to be polished are Since multiple contacts can be made at very close intervals, polishing efficiency is high, high polishing speed is obtained, long wave waviness is reduced, and extreme deformations such as molds and wedges Since it is not a degree, it is thought that a projection defect is also reduced. However, the present disclosure is not limited to the interpretation of this mechanism.

  The CV value (CV90) of the silica particles A used in the present disclosure is improved in the polishing rate in rough polishing, long wavelength waviness and protrusion defects after rough polishing, and long wavelength waviness and protrusion defects after finish polishing. In view of the above, when the average particle diameter (D1) is 50.0 nm or more and 125.0 nm or less, 10% or more and 40% or less, or when the average particle diameter (D1) is 120.0 nm or more and 300.0 nm or less The range of 20% to 35% is preferable. Here, the CV value is a value of a coefficient of variation obtained by dividing the standard deviation based on the scattering intensity distribution by the average particle diameter and multiplying by 100 in the dynamic light scattering method. The CV value measured by (side scatter) is referred to as CV90, and the CV value measured at a detection angle of 30 ° (forward scatter) is referred to as CV30. Specifically, the CV value of the silica particles A can be obtained by the method described in Examples.

[Average particle diameter by dynamic light scattering method (D1)]
In the present disclosure, the average particle diameter (D1) of the silica particles refers to an average particle diameter based on a scattering intensity distribution measured by a dynamic light scattering method. The average particle diameter based on the scattering intensity distribution measured at a detection angle of 90 ° in the dynamic light scattering method. The average particle diameter (D1) of the silica particles A in the present disclosure can be specifically obtained by the method described in the examples.

  The average particle diameter (D1) of the silica particles A is 50 from the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after final polishing. A range of 0.0 nm to 125.0 nm or a range of 120.0 nm to 300.0 nm is preferable. When the average particle diameter (D1) of the silica particles is within the above range, it is considered that the physical polishing force at the time of polishing cutting is strong and the long wavelength waviness is effectively reduced.

[Specific surface area equivalent particle diameter (D2) of silica particle A by BET method]
The specific surface area equivalent particle diameter (D2) of the silica particle A of the present disclosure is given by the formula D2 = 2720 / S [nm] from the specific surface area Sm ² / g measured by the nitrogen adsorption method (BET method).

[(D1 / D2) of silica particles A]
The ratio (D1 / D2) of the average particle diameter (D1) measured by the dynamic light scattering method and the specific surface area converted particle diameter (D2) by the BET method means the degree of irregularity of the silica particles A, and in rough polishing (D1 / D2) is 1.50 or more and 4.00 or less from the viewpoint of improving the polishing rate, reducing long wavelength waviness and protrusion defects after rough polishing, and reducing long wavelength waviness and protrusion defects after finish polishing. It is preferable. In general, the average particle diameter (D1) measured by the dynamic light scattering method is processed in the case of irregularly shaped particles by detecting the light scattering in the long direction, and thus the lengths in the long direction and the short direction are considered. Thus, the larger the degree of deformity, the larger the numerical value, and the specific surface area equivalent particle diameter (D2) by the BET method is expressed in terms of a sphere based on the obtained volume of the particle, and thus becomes a smaller numerical value than D1. The non-spherical silica a is a non-spherical silica having a relatively small ratio (D1 / D2) between the average particle diameter (D1) measured by the dynamic light scattering method and the specific surface area converted particle diameter (D2) by the BET method. It is thought that there are many in the whole system. On the other hand, the non-spherical silica b has a relatively large ratio (D1 / D2) of the average particle diameter (D1) measured by the dynamic light scattering method and the specific surface area equivalent particle diameter (D2) by the BET method. It is considered that many spherical silicas exist in the entire system. This is because, when the shape of the non-spherical silica is too distorted (= D1 / D2 is large), the laser light is also used in the measurement in the dilution system. Presumed to be due to the behavior of multiple scattering due to the shape of the particle itself, resulting in the behavior that the difference in forward and side or backscattering scattering intensity disappears and the ΔCV value (angle dependence of the scattering intensity distribution) decreases. Is done. However, the present disclosure is not limited to the interpretation of this mechanism.

[Method for producing silica particle A]
Silica particles A are manufactured by a flame melting method, a sol-gel method, and a pulverization method from the viewpoint of improving the polishing rate in rough polishing, from the viewpoint of reducing long-wave waviness after rough polishing, and from the viewpoint of reducing protrusion defects. The silica particles are preferably produced by a particle growth method using an aqueous alkali silicate solution as a starting material. In addition, as a usage form of the silica particle A, it is preferable that it is a slurry form.

Silica particles are usually 1) Put a mixed solution (seed solution) of less than 10% by weight of No. 3 sodium silicate and seed particles (small-size silica) into the reaction layer and heat to 60 ° C or higher. 2) Spherical particles are grown by dropping an acidic active silicic acid aqueous solution obtained by passing No. 3 silicate through a cation exchange resin and an alkali (alkali metal or quaternary ammonium) to keep the pH constant, and 3) evaporating after aging. It is obtained by concentrating by a method or an ultrafiltration method (Japanese Patent Application Laid-Open No. 47-1964, Japanese Patent Publication No. 1-223412, Japanese Patent Publication No. 4-55125, Japanese Patent Publication No. 4-55127). However, it is often reported that non-spherical silica particles A can be produced if the steps are slightly changed in the same production process. For example, activated silicic acid is very unstable, and when a polyvalent metal ion such as Ca or Mg is intentionally added, an elongated silica sol can be produced. Further, the temperature of the reaction layer (evaporates when the boiling point of water is exceeded and the silica is dried at the gas-liquid interface), the pH of the reaction layer (silica particles are liable to be linked below 9), the SiO ₂ / M ₂ O of the reaction layer. (M is an alkali metal or quaternary ammonium), and non-spherical silica can be produced by changing the molar ratio (selectively producing non-spherical silica at 30 to 60) (Japanese Patent Publication No. 8-5657, Patent 2803134, JP-A-2003-133267, JP-A-2006-80406, JP-A-2007-153671, JP-A-2009-137791, JP-A-2009-149493, JP-A-2011-16702). However, the manufacturing method of the silica particle A is limited to these and is not interpreted.

  Further, the method for adjusting the particle size distribution of the silica particles A is not particularly limited, but a method of giving a desired particle size distribution by adding particles as a new nucleus in the process of particle growth in the production stage, Examples thereof include a method of mixing two or more types of silica particles having different particle size distributions so as to have a desired particle size distribution.

[Content of silica particles A in polishing liquid composition A]
The content of silica particles A contained in the polishing liquid composition A improves the polishing rate in rough polishing, reduces long-wave waviness and protrusion defects after rough polishing, and reduces long-wave waviness and protrusion defects after final polishing. From a viewpoint, 0.1 mass% or more is preferable, 0.5 mass% or more is more preferable, 1 mass% or more is further preferable, 2 mass% or more is further more preferable, and 5 mass% or more is further more preferable. The content is preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less, still more preferably 15% by mass or less, and even more preferably 10% by mass or less from the viewpoint of economy. Even more preferred.

[Step (1): Acid]
Polishing liquid composition A contains an acid from the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after finish polishing. Use of the acid in the polishing liquid composition A includes use of an acid and / or a salt thereof. Examples of acids used include nitric acid, sulfuric acid, sulfurous acid, persulfuric acid, hydrochloric acid, perchloric acid, phosphoric acid, phosphonic acid, phosphinic acid, pyrophosphoric acid, tripolyphosphoric acid, amidosulfuric acid, 2-aminoethylphosphonic acid, and the like. 1-hydroxyethylidene-1,1-diphosphonic acid, 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, 2-phosphonobutane-1,2-dicarboxylic acid, 1-phosphonobutane-2 Organic phosphonic acids such as 3,4-tricarboxylic acid and α-methylphosphonosuccinic acid, aminocarboxylic acids such as glutamic acid, picolinic acid and aspartic acid, citric acid, tartaric acid, oxalic acid, nitroacetic acid, maleic acid, oxaloacetic acid, etc. And carboxylic acid. Among these, phosphoric acid, sulfuric acid, citric acid, tartaric acid, malein from the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after final polishing. More preferred are acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid) and salts thereof, sulfuric acid, 1-hydroxyethylidene -1,1-diphosphonic acid, aminotri (methylenephosphonic acid) and their salts are more preferred, and sulfuric acid is even more preferred.

  These acids and salts thereof may be used alone or in combination of two or more. However, the polishing rate is improved in rough polishing, long-wave waviness and protrusion defects after rough polishing, and long-wavelength after finish polishing. From the viewpoint of reducing waviness and protrusion defects, it is preferable to use a mixture of two or more, phosphoric acid, sulfuric acid, citric acid, tartaric acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri (methylenephosphonic acid) More preferably, a mixture of two or more acids selected from the group consisting of:

  When these acid salts are used, there is no particular limitation, and specific examples include 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. Among these, from the viewpoints of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after final polishing, it is a metal belonging to Group 1A or ammonium. Salts are preferred.

  The content of the acid in the polishing composition A is from the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after final polishing. 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, and 5.0% by mass or less. More preferably, it is 4.0 mass% or less, More preferably, it is 3.0 mass% or less, More preferably, it is 2.0 mass% or less.

[Step (1): Oxidizing agent]
The polishing composition A contains an oxidizing agent from the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after final polishing. To do. The oxidizing agent used includes at least one selected from the group consisting of hydrogen peroxide, peroxodisulfate, and periodic acid and salts thereof. Further, other peroxides, permanganic acid or a salt thereof, chromic acid or a salt thereof, peroxo acid or a salt thereof, oxygen acid or a salt thereof may be included. Periodic acid may be metaperiodic acid or orthoperiodic acid. These oxidizing agents may be used alone or in admixture of two or more.

  The content of the oxidizing agent in the polishing composition A is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and further preferably 0.1% by mass from the viewpoint of improving the polishing rate in the rough polishing. From the viewpoint of reducing long-wave waviness after rough polishing, reducing protrusion defects, and reducing long-wave waviness and protrusion defects after finish polishing, preferably 4% by weight or less, more preferably 2% by weight. Hereinafter, it is more preferably 1.5% by mass or less.

[Step (1): Oxidation promotion aid]
From the viewpoint of improving the polishing rate, reducing the long-wave waviness and protrusion defects after rough polishing, and reducing the long-wave waviness and protrusion defects after finish polishing, the polishing liquid composition A is prepared from hydrogen peroxide, peroxodisulfuric acid. Among the salt and periodic acid or a salt thereof, when the periodic acid or a salt thereof is not included, an oxidation promotion aid is further contained. The oxidizing agents used include iron sulfate, iron nitrate, ammonium sulfate iron, iron perchlorate, iron chloride, iron citrate, iron iron citrate, iron oxalate, iron iron oxalate, and iron chelate complexes of ethylenediaminetetraacetic acid. Etc. Among these, from the viewpoints of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after final polishing, iron sulfate, iron nitrate, and ammonium iron sulfate are used. Preferably, iron sulfate is more preferable.

  These oxidation promotion aids react with the oxidant and are activated. From the viewpoint of avoiding deterioration of the stability of the oxidant by coexisting with the oxidant for a long time in the polishing liquid composition A, the polishing liquid other than the oxidation promotion auxiliary and the oxidation promotion auxiliary immediately before polishing is performed. It is preferable to mix with the composition A. Alternatively, from the same viewpoint, two polishing liquid supply ports are provided on the polishing machine, and the polishing liquid composition A and the oxidation promotion auxiliary other than the oxidation promotion auxiliary are simultaneously mixed during polishing to mix in the polishing machine. Is preferred. Therefore, in the present disclosure, “supplying the polishing liquid composition A to the surface to be polished of the substrate to be polished” means that in one or a plurality of embodiments, the oxidation promotion aid and the oxidation promotion aid other than the oxidation promotion aid immediately before polishing. Supplying the polishing composition A mixed and / or supplying the oxidation promoting aid and the polishing composition A other than the oxidation promoting aid separately to the polishing machine and mixing in the polishing machine including.

  The content of the oxidation promoting aid in the polishing liquid composition A is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and further preferably 0.1% by mass from the viewpoint of improving the polishing rate. From the viewpoints of reducing long-wave waviness after rough polishing, reducing protrusion defects, and reducing long-wave waviness and protrusion defects after finish polishing, 4.0 mass% or less, more preferably 2. It is 0 mass% or less, More preferably, it is 1.0 mass% or less.

[Step (1): Water]
Polishing liquid composition A contains water as a medium. As water, distilled water, ion-exchanged water, pure water, ultrapure water, or the like can be used. The content of water in the polishing liquid composition A is preferably 55% by mass or more and 99.98% by mass or less, more preferably 70% by mass or more and 98% by mass or less, because the handling of the polishing liquid composition becomes easy. More preferably, it is 80 mass% or more and 97 mass% or less, More preferably, it is 85 mass% or more and 97 mass% or less.

[Step (1): Other components]
In the polishing composition A, other components can be blended as necessary. Examples of other components include buffers, thickeners, dispersants, rust inhibitors, basic substances, surfactants, and polymer compounds. The content of these other optional components in the polishing liquid composition A is preferably blended within a range not impairing the effects of the present disclosure, preferably 0% by mass to 10% by mass, and more preferably 0% by mass to 5% by mass. % Or less is more preferable.

[PH of polishing composition A]
From the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing the long-wave waviness and protrusion defects after final polishing, the pH of the polishing liquid composition A is the above-mentioned acid or It is preferable to adjust the pH to 0.5 or more and 6.0 or less using a known pH adjuster, more preferably pH 0.7 or more, still more preferably pH 0.8 or more, and even more preferably pH 0.9 or more. More preferably, the pH is 4.0 or less, still more preferably pH 3.0 or less, and still more preferably pH 2.0 or less. In addition, said pH is pH of polishing liquid composition in 25 degreeC, can be measured using a pH meter, and is a numerical value 40 minutes after immersing an electrode in polishing liquid composition.

[Method for Preparing Polishing Liquid Composition A]
The polishing liquid composition A can be prepared, for example, by mixing the silica particles A and water, and, if desired, an oxidizing agent, an acid and other components by a known method. As another embodiment, the polishing liquid composition A may be prepared as a concentrate. The mixing is not particularly limited, and can be performed using a homomixer, a homogenizer, an ultrasonic disperser, a stirrer such as a wet ball mill, or the like.

[Step (1): Polishing pad]
There is no restriction | limiting in particular as a polishing pad used by the rough | crude grinding | polishing process of a process (1), It is using the polishing pad of a suede type, a nonwoven fabric type, a polyurethane closed-cell foam type, or the two-layer type which laminated | stacked these. However, a suede type polishing pad is preferable from the viewpoint of improving the polishing rate. A suede type polishing pad is composed of a foam layer having a base layer and spindle-shaped pores perpendicular to the base layer. Examples of the material of the base layer include a non-woven fabric made of natural fibers such as cotton and synthetic fibers, and a base layer obtained by filling a rubber-like substance such as styrene butadiene rubber. From the viewpoint of reducing the later long-wave swell and protrusion defects, a polyester film is preferable, and a polyethylene terephthalate (PET) film from which a high-hardness resin film can be obtained is more preferable. In addition, examples of the material for the foam layer include polyurethane, polystyrene, polyester, polyvinyl chloride, natural rubber, and synthetic rubber. From the viewpoint of improving the physical properties such as compressibility and improving the abrasion resistance during polishing. Therefore, polyurethane is preferable, and polyurethane elastomer is more preferable.

  Furthermore, when polyurethane is selected as the material of the foam layer of the polishing pad, the main component is from the viewpoint of suppressing pad deterioration due to the influence of chemical components such as acid, oxidizing agent and oxidation promoting aid during polishing. It preferably has an ester skeleton or an ether skeleton, and more preferably has an ether skeleton.

  In addition, the average pore diameter of the polishing pad used in the step (1) is the improvement of the polishing rate in rough polishing, the reduction of long-wave waviness and protrusion defects after rough polishing, and the long-wave waviness and protrusion defects after final polishing. From the viewpoint of reduction, it is preferably 10 μm or more, more preferably 20 μm or more, still more preferably 30 μm or more, even more preferably 35 μm or more, and preferably 100 μm or less, more preferably 80 μm or less, still more preferably 60 μm or less, Even more preferably, it is 55 μm or less.

[Step (1): Polishing load]
In the present disclosure, the polishing load means the pressure of the surface plate applied to the polishing surface of the substrate to be polished during polishing. The polishing load in step (1) is 30.0 kPa or less from the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after final polishing. More preferably 25.0 kPa or less, even more preferably 20.0 kPa or less, even more preferably 18.0 kPa or less, even more preferably 16.0 kPa or less, even more preferably 14.0 kPa or less, even more preferably 11.0 kPa or less. The polishing load is preferably 3.0 kPa or more from the viewpoint of improving the polishing rate in rough polishing, reducing long-wave waviness and protrusion defects after rough polishing, and reducing long-wave waviness and protrusion defects after finish polishing. More preferably, it is 5.0 kPa or more, More preferably, it is 7.0 kPa or more, More preferably, it is 8.0 kPa or more, More preferably, it is 9.0 kPa or more. The polishing load can be adjusted by applying air pressure or weight to the surface plate or the substrate.

[Step (1): Polishing amount]
In the step (1), the amount of polishing per unit area (1 cm ² ) of the substrate to be polished and the polishing time per minute is long wavelength waviness and protrusion defects after rough polishing, and long wavelength waviness and protrusions after finish polishing. From the viewpoint of reducing defects, 0.05 mg / (cm ² · min) or more is preferable, more preferably 0.08 mg / (cm ² · min) or more, and further preferably 0.10 mg / (cm ² · min) or more. Even more preferably, it is 0.12 mg / (cm ² · min) or more. On the other hand, from the viewpoint of reducing long-wave waviness and protrusion defects after rough polishing and reducing long-wave waviness and protrusion defects after finish polishing without significantly increasing the polishing time of rough polishing, 0.50 mg / ( cm ² · min) or less, and more preferably 0.30 mg / (cm ² · min) or less, more preferably 0.28 mg / (cm ² · min) or less, even more preferably 0.25 mg / (cm ²・ Min.

[Step (1): Supply rate of polishing composition A]
The supply rate of the polishing liquid composition A in the step (1) is preferably 0.25 mL / min or less per 1 cm ^{2 of the} substrate to be polished, more preferably 0.20 mL / min or less, further preferably 0, from the viewpoint of economy. 15 mL / min or less. The supply rate is preferably 0.01 mL / min or more per 1 cm ^{2 of the} substrate to be polished, more preferably 0.025 mL / min or more, and further preferably 0.05 mL / min or more from the viewpoint of improving the polishing rate. is there.

[Step (1): Method of supplying polishing liquid composition A to polishing machine]
Examples of a method for supplying the polishing liquid composition A to the polishing machine include a method in which the polishing liquid composition A is continuously supplied using a pump or the like. When supplying the polishing liquid composition A to the polishing machine, in addition to the method of supplying it with one liquid containing all the components, considering the storage stability of the polishing liquid composition A, a plurality of component liquids for blending It can also be divided into two liquids or more. In the latter case, for example, the plurality of compounding component liquids are mixed into the polishing liquid composition A in the supply pipe or on the substrate to be polished.

[Step (2): Cleaning step]
Step (2) is a step of cleaning the substrate obtained in step (1). Step (2) is a step of cleaning the substrate that has been subjected to the rough polishing in step (1) with a cleaning composition in one or more embodiments. Although the cleaning method in the step (2) is not particularly limited, in one or a plurality of embodiments, the method of immersing the substrate obtained in the step (1) in the cleaning composition (cleaning method a), and the cleaning agent The method (cleaning method b) which injects a composition and supplies a cleaning composition on the surface of the board | substrate obtained by process (1) is mentioned.

[Step (2): Cleaning method a]
In the cleaning method a, the conditions for immersing the substrate in the cleaning composition are not particularly limited. For example, the temperature of the cleaning composition is 20 ° C. or more and 100 ° C. or less from the viewpoint of safety and operability. The immersion time is preferably 10 seconds or longer and 30 minutes or shorter from the viewpoint of the cleaning properties and production efficiency of the cleaning composition. Moreover, it is preferable that ultrasonic vibration is given to the cleaning composition from the viewpoint of improving the removability of the residue and the dispersibility of the residue. The frequency of the ultrasonic wave is preferably 20 kHz to 2000 kHz, more preferably 40 kHz to 2000 kHz, and still more preferably 40 kHz to 1500 kHz.

[Step (2): Cleaning method b]
In the cleaning method b, from the viewpoint of promoting the cleaning performance of the residue and the solubility of the oil, the cleaning composition to which ultrasonic vibration is applied is injected to bring the cleaning composition into contact with the surface of the substrate. Or cleaning the surface by supplying the cleaning composition onto the surface of the substrate to be cleaned by injection and rubbing the surface supplied with the cleaning composition with a cleaning brush. preferable. Furthermore, the cleaning composition to which ultrasonic vibration is applied is supplied to the surface to be cleaned by injection, and the surface to which the cleaning composition is supplied is cleaned by rubbing with a cleaning brush. Is preferred.

  As means for supplying the cleaning composition onto the surface of the substrate to be cleaned, known means such as a spray nozzle can be used. Moreover, there is no restriction | limiting in particular as a brush for washing | cleaning, For example, well-known things, such as a nylon brush and a PVA (polyvinyl alcohol) sponge brush, can be used. The ultrasonic frequency may be the same as the value preferably adopted in the method (a).

  In the step (2), in addition to the cleaning method a and / or the cleaning method b, one or more steps using known cleaning such as rocking cleaning, cleaning using rotation of a spinner, paddle cleaning, scrub cleaning, and the like are included. But you can.

[Step (2): Cleaning composition]
As a cleaning composition of a process (2), in one or some embodiment, what contains an alkali agent, water, and various additives as needed can be used.

[Step (2): Alkaline agent in cleaning composition]
The alkaline agent used in the cleaning composition may be either an inorganic alkaline agent or an organic alkaline agent. Examples of the inorganic alkaline agent include ammonia, potassium hydroxide, and sodium hydroxide. Examples of the organic alkali agent include one or more selected from the group consisting of hydroxyalkylamine, tetramethylammonium hydroxide, and choline. These alkaline agents may be used alone or in combination of two or more. From the viewpoint of improving the dispersibility of the residue on the substrate of the cleaning composition and improving the storage stability, the alkaline agent includes potassium hydroxide, sodium hydroxide, monoethanolamine, methyldiethanolamine, and aminoethylethanol. At least one selected from the group consisting of amines is preferred, and at least one selected from the group consisting of potassium hydroxide and sodium hydroxide is more preferred.

  The content of the alkaline agent in the cleaning composition is 0.05% by mass or more from the viewpoint of developing a high cleaning property with respect to the residue on the substrate of the cleaning composition and enhancing safety during handling. Preferably, it is 0.08% by mass or more, more preferably 0.1% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, more preferably 3% by mass. More preferably, it is as follows.

  From the viewpoint of improving the dispersibility of the residue on the substrate, the pH of the cleaning composition is preferably 8 or more, more preferably 9 or more, still more preferably 10 or more, and even more preferably 11 or more. , 13 or less is preferable. In addition, said pH is pH of the cleaning composition at 25 degreeC, can be measured using a pH meter, and is a numerical value 40 minutes after immersing an electrode in cleaning composition.

[Step (2): Various additives in the cleaning composition]
In addition to alkaline agents, the detergent composition includes nonionic surfactants, chelating agents, ether carboxylates or fatty acids, anionic surfactants, water-soluble polymers, antifoaming agents (surfactants corresponding to the components) May be included), alcohols, preservatives, antioxidants, and the like.

  The content of components other than water contained in the cleaning composition is a concentration that exhibits sufficient effects for improving workability, economy and storage stability, and is compatible with improving storage stability. From the viewpoint, when the total content of water and components other than water is 100% by mass, it is preferably 10% by mass or more, more preferably 15% by mass or more, and preferably 60% by mass or less. More preferably, it is 50 mass% or less, More preferably, it is 40 mass% or less.

  The cleaning composition is used after being diluted. In consideration of washing efficiency, the dilution rate is preferably 10 times or more, more preferably 20 times or more, further preferably 50 times or more, preferably 500 times or less, more preferably 200 times or less, and still more preferably 100 times. It is as follows. The water for dilution may be the same as the above-mentioned polishing composition. The cleaning composition may be a concentrate based on the dilution factor.

[Step (3): Final polishing step]
In the step (3), the polishing composition B containing the silica particles B and water is supplied to the surface to be polished of the substrate obtained in the step (2), a polishing pad is brought into contact with the surface to be polished, and the polishing is performed. It is a step of moving the pad and / or the substrate to be polished to polish the surface to be polished. The polishing machine used in step (3) is from the viewpoint of reducing long-wavelength waviness and protrusion defects after finish polishing and using pads having different pore diameters from rough polishing in order to efficiently reduce other surface defects. The polishing machine is different from the polishing machine used in step (1). The supply rate of the polishing liquid composition B used in the step (3) and the method of supplying the polishing liquid composition B to the polishing machine can be the same as those of the polishing liquid composition A described above.

  The method of manufacturing a magnetic disk substrate according to the present disclosure includes a rough polishing step in step (1), a cleaning step in step (2), and a final polishing step in step (3), whereby long-wave waviness after rough polishing. In addition, it is possible to efficiently manufacture a substrate in which long-wave waviness and protrusion defects after finish polishing are reduced.

[Step (3): Polishing liquid composition B]
Polishing liquid composition B used at a process (3) contains the silica particle B as an abrasive from a viewpoint of protrusion defect reduction. The silica particles B used are preferably colloidal silica from the viewpoint of reducing long wavelength waviness and protrusion defects after finish polishing. Moreover, it is preferable that the polishing liquid composition B does not contain an alumina particle from a viewpoint of reducing the long wavelength waviness and protrusion defect after finish polishing.

[Step (3): Silica Particle B]
The average particle diameter (D1) of the silica particles B used in the present disclosure by the dynamic light scattering method, the specific surface area converted particle diameter (D2) by the BET method, and their ratio (D1 / D2), ΔCV value, CV90 Each parameter such as can be defined in the same manner as in the case of the silica particle A described above, and specifically can be obtained by the method described in the examples.

[Step (3): Average particle diameter of silica particles B by dynamic light scattering method (D1)]
The average particle diameter (D1) of the silica particles B of the present disclosure is preferably 1.0 nm or more, more preferably 5.0 nm or more, and still more preferably 10 from the viewpoint of reducing long wavelength waviness and protrusion defects after finish polishing. It is 0.0 nm or more and 40.0 nm or less is preferable, More preferably, it is 37.0 nm or less, More preferably, it is 35.0 nm or less. Further, the average particle diameter (D1) of the silica particles B is preferably smaller than the average particle diameter (D1) of the silica particles A from the viewpoint of reducing long wavelength waviness and protrusion defects after finish polishing. In addition, this average particle diameter can be calculated | required by the method as described in an Example.

[Step (3): (D1 / D2) of silica particle B]
The ratio (D1 / D2) of the average particle diameter (D1) measured by the dynamic light scattering method of the silica particles B of the present disclosure to the specific surface area equivalent particle diameter (D2) by the BET method is not particularly limited, but the finish From the viewpoint of reducing long-wave waviness and protrusion defects after polishing, (D1 / D2) is preferably in the range of 1.00 to 1.50, more preferably 1.00 to 1.40, More preferably, it is the range of 1.00 or more and 1.30 or less.

[Step (3): ΔCV value of silica particle B]
The ΔCV value of the silica particle B of the present disclosure is 0% or more and 10.0% or less, preferably 0% or more and 8.% from the viewpoint of reducing scratches, long wavelength waviness and protrusion defects on the substrate surface after finish polishing. It is 0% or less, more preferably 0% or more and 6.0% or less, and still more preferably 0% or more and 5.0% or less. Further, from the viewpoint of improving the productivity of the silica particles of the polishing composition B, the ΔCV value is preferably 0.001% or more, and more preferably 0.01% or more.

  In addition, the CV value (CV90) of the silica particles B of the present disclosure is preferably 1.0% or more, and more preferably 5. 5% from the viewpoint of reducing scratches, long wavelength waviness, and protrusion defects on the substrate surface after finish polishing. 0% or more, more preferably 10.0% or more, even more preferably 20.0% or more, preferably 35.0% or less, more preferably 33.0% or less, and even more preferably 30.0% or less It is. Specifically, the CV value of the silica particle B can be obtained by the method described in Examples.

Examples of the method for adjusting the ΔCV value of the silica particles B include the following methods for preventing generation of silica aggregates of 50 nm to 200 nm in the preparation of the polishing liquid composition.
A) Method by filtration of polishing liquid composition B) Method by process control at the time of colloidal silica production

  In the above A), ΔCV can be reduced by removing silica aggregates of 50 to 200 nm by, for example, centrifugation or fine filter filtration (Japanese Patent Application Laid-Open No. 2006-102829 and Japanese Patent Application Laid-Open No. 2006-136996). Specifically, a colloidal silica aqueous solution appropriately diluted so as to have a silica concentration of 20% by mass or less can be removed under conditions where 50 nm particles produced by the stokes equation can be removed (for example, 10,000 G or more, centrifuge tube height of about 10 cm). ΔCV can be reduced by a method of centrifuging for 2 hours or more, a method of pressure filtration using a membrane filter (for example, Advantech, Sumitomo 3M, Millipore) having a pore size of 0.05 μm or 0.1 μm.

  The silica particles B are usually 1) a mixed solution (seed solution) of less than 10% by weight of No. 3 sodium silicate and seed particles (small particle silica) is put in a reaction layer and heated to 60 ° C. or higher. ) Dropping an acidic active silicic acid aqueous solution in which No. 3 sodium silicate was passed through a cation exchange resin and an alkali (alkali metal or quaternary ammonium) dropwise to grow a spherical particle with a constant pH 3) It can be obtained by concentrating by an evaporation method or an ultrafiltration method after aging (Japanese Patent Laid-Open No. 47-1964, Japanese Patent Publication No. 1-223412, Japanese Patent Publication No. 4-55125, Japanese Patent Publication No. 4-55127). That is, in the above B), ΔCV can be adjusted to be small by performing process control so as not to be a condition for generating non-spherical silica locally in a known spherical colloidal silica production process.

  The method for adjusting the particle size distribution of the silica particles B is not particularly limited, but a method of giving a desired particle size distribution by adding particles as new nuclei in the process of particle growth in the production stage, or different particles Examples thereof include a method of mixing two or more kinds of silica particles having a size distribution to give a desired particle size distribution.

[Content of Silica Particle B in Polishing Liquid Composition B]
The content of the silica particles B contained in the polishing composition B is preferably 0.5% by mass or more from the viewpoint of improving the polishing rate in finish polishing and from the viewpoint of reducing long-wave waviness and protrusion defects after finish polishing. 1.0 mass% or more is more preferable, 3.0 mass% or more is more preferable, 4.0 mass% or more is further more preferable, 20 mass% or less is preferable, 15 mass% or less is more preferable, 10 mass% is more preferable. The following is more preferable, and 8% by mass or less is even more preferable.

[Step (3): pH of silica particles B in polishing liquid composition B]
The pH of the polishing composition B is adjusted to pH 0. from the viewpoint of improving the polishing rate in the final polishing and from the viewpoint of reducing long-wave waviness and protrusion defects after the final polishing using the above-mentioned acid or a known pH adjuster. It is preferable to adjust to 5 or more and 3.0 or less, more preferably pH 0.8 or more, further preferably pH 1.0 or more, still more preferably pH 1.2 or more, more preferably pH 2.5 or less, still more preferably. Is pH 2.0 or less, and even more preferably pH 1.8 or less. In addition, said pH is pH of polishing liquid composition in 25 degreeC, can be measured using a pH meter, and is a numerical value 40 minutes after immersing an electrode in polishing liquid composition.

  Polishing liquid composition B contains 1 or more types chosen from the polymer which has a heterocyclic aromatic compound, a polyvalent amine compound, and an anionic group from a viewpoint of reducing the long wavelength waviness and protrusion defect after final polishing. It is preferable to include two or more types, and it is more preferable to include a heterocyclic aromatic compound, a polyvalent amine compound, and a polymer having an anionic group.

  The polishing composition B preferably contains an acid and an oxidizing agent from the viewpoint of improving the polishing rate. About the preferable usage aspect of an acid, it is the same as that of the case of the above-mentioned polishing liquid composition A. Further, the water used for the polishing liquid composition B and the method for preparing the polishing liquid composition B are the same as those of the polishing liquid composition A described above.

[Polishing liquid composition B: oxidizing agent]
The polishing composition B preferably contains an oxidizing agent from the viewpoint of reducing long-wave waviness and protrusion defects after finish polishing. As the oxidizing agent, from the viewpoint of reducing long-wave waviness and protrusion defects after finish polishing, peroxide, permanganic acid or a salt thereof, chromic acid or a salt thereof, peroxo acid or a salt thereof, oxygen acid or a salt thereof, Metal salts etc. are mentioned. Among these, hydrogen peroxide, iron nitrate (III), peracetic acid, ammonium peroxodisulfate, iron sulfate (III), and ammonium iron sulfate (III) are preferable, and metal ions do not adhere to the surface from the viewpoint of improving the polishing rate. From the viewpoint of being used for general purposes and inexpensive, hydrogen peroxide is more preferable. These oxidizing agents may be used alone or in admixture of two or more.

[Step (3): Polishing pad]
As the polishing pad used in the step (3), the same type of polishing pad as that used in the step (1) can be used. The average pore diameter of the polishing pad used in the step (3) is preferably 1 to 50 μm, more preferably 2 to 40 μm, and further preferably 3 to 3% from the viewpoint of reducing long-wave waviness and protrusion defects after finish polishing. 30 μm.

[Step (3): Polishing load]
The polishing load in the step (3) is preferably 16.0 kPa or less, more preferably 14.0 kPa or less, still more preferably 10.0 kPa or less, and even more, from the viewpoint of reducing long wavelength waviness and protrusion defects after finish polishing. Preferably it is 8.0 kPa or less. From the viewpoint of reducing long-wave waviness and protrusion defects after finish polishing, the pressure is preferably 6.0 kPa or more, more preferably 7.0 kPa or more, and further preferably 7.5 kPa or more.

[Step (3): Polishing amount]
In the step (3), the polishing amount per unit area (1 cm ² ) of the substrate to be polished and the polishing time per minute is 0.02 mg / (cm 2) from the viewpoint of reducing long wavelength waviness and protrusion defects after final polishing. preferably ² · min) or more, more preferably 0.03 mg / (cm ² · min) or higher, further preferably 0.04 mg / (cm ² · min) or more. Further, from the viewpoint of improving productivity, preferably 0.15mg / (cm ² · min) or less, more preferably 0.12mg / (cm ² · min) or less, more preferably 0.10mg / (cm ² · Min) or less.

  According to the manufacturing method of the present disclosure, it is possible to provide a magnetic disk substrate with reduced long-wave waviness and protrusion defects, and thus it is suitably used for polishing a perpendicular magnetic recording type magnetic disk substrate that requires a high degree of surface smoothness. be able to.

[Polishing method]
As another aspect, the present disclosure relates to a polishing method having the above-described step (1), step (2), and step (3). As one non-limiting embodiment of the present aspect, (1) a polishing liquid composition A containing silica particles A, an acid, an oxidant, and water is supplied to the surface to be polished of the substrate to be polished, and the surface to be polished is polished. Contacting the pad and moving the polishing pad and / or the substrate to be polished to polish the surface to be polished; (2) cleaning the substrate obtained in step (1); and (3) silica A polishing liquid composition B containing particles B and water is supplied to the surface to be polished of the substrate obtained in step (2), the polishing pad is brought into contact with the surface to be polished, and the polishing pad and / or the object to be polished A step of polishing the surface to be polished by moving the substrate, wherein the steps (1) and (3) are performed by another polishing machine, and the silica particle A has a ΔCV value of 10.0% or more and 30.30. 0% or less and the average particle size (D1) is 50.0 nm or more and 1 Nonspherical silica a having a size of 5.0 nm or less, or Nonspherical silica b having a ΔCV value of 0.0% or more and less than 10.0% and an average particle diameter (D1) of 120.0 nm or more and 300.0 nm or less And the oxidizing agent is at least one selected from the group consisting of hydrogen peroxide, peroxodisulfate, and periodic acid and salts thereof,
When it does not contain periodic acid or its salt as the oxidizing agent, iron sulfate, iron nitrate, ammonium sulfate iron, iron perchlorate, iron chloride, iron citrate, ammonium iron citrate, iron oxalate, iron iron oxalate And at least one oxidation promoting aid selected from the group consisting of iron chelate complex salts of ethylenediaminetetraacetic acid, and the ΔCV value represents the standard deviation based on the scattering intensity distribution at a detection angle of 30 ° by the dynamic light scattering method. The value obtained by dividing the average particle size based on the scattering intensity distribution by 100 (CV30) and the standard deviation based on the scattering intensity distribution at a detection angle of 90 ° by the dynamic light scattering method are the average particle size based on the scattering intensity distribution. (CV90 = CV30−CV90) and the average particle size (D1) is a detection angle of 90 ° by the dynamic light scattering method. An average particle size based on scattering intensity distribution that include polishing method for a magnetic disk substrate. Regarding substrate to be polished, polishing pad, polishing liquid composition A, silica particle A, polishing liquid composition B, silica particle B, polishing method and conditions, cleaning composition and cleaning method in steps (1) to (3) Can be the same as the above-described method for manufacturing a magnetic disk substrate of the present disclosure.

  By using the polishing method of the present disclosure, a magnetic disk substrate with reduced long-wave waviness and protrusion defects, particularly a perpendicular magnetic recording type magnetic disk substrate, is preferably provided. As a result, it is possible to manufacture a magnetic disk substrate whose substrate quality is improved by suppressing a decrease in product yield, with no significant decrease in polishing speed, and with high productivity without significantly increasing the polishing time for rough polishing. An effect can be produced.

  In one or a plurality of embodiments, a magnetic disk substrate manufacturing method and polishing method according to the present disclosure include a first polishing machine that polishes a substrate to be polished using the polishing liquid composition A, and the first polishing machine. It can be performed by a magnetic disk substrate polishing system comprising a cleaning unit for cleaning the polished substrate and a second polishing machine for polishing the cleaned substrate using the polishing composition B. Therefore, in one aspect, the present disclosure provides a first polishing machine that polishes a substrate to be polished using the polishing composition A, a cleaning unit that cleans the substrate polished by the first polishing machine, and a polishing composition. A polishing system for a magnetic disk substrate comprising a second polishing machine that polishes the substrate after cleaning using the product B, wherein the polishing composition A contains silica particles A, an acid, an oxidizing agent, and water. In addition, the silica particles A do not contain alumina abrasive grains, and the silica particles A have a ΔCV value of 10.0% or more and 30.0% or less, and an average particle diameter (D1) of 50 nm or more and 125 nm or less. Or a non-spherical silica b having a ΔCV value of 0% or more and less than 10.0% and an average particle diameter (D1) of 120 nm or more and 300 nm or less, and the oxidizing agent is hydrogen peroxide, peroxodisulfate, Periodate and its When it is at least one selected from the group consisting of salts and does not contain periodic acid or a salt thereof as the oxidizing agent, iron sulfate, iron nitrate, ammonium sulfate iron, iron perchlorate, iron chloride, iron citrate, citric acid Containing at least one oxidation promoting aid selected from the group consisting of iron chelate complex salts of ammonium iron oxide, iron oxalate, iron iron oxalate and ethylenediaminetetraacetic acid, and the polishing composition B contains water and silica particles B The present invention relates to a polishing system that is a polishing liquid composition that contains and does not contain alumina abrasive grains. Regarding the substrate to be polished, the polishing pad used in each polishing machine, the polishing liquid composition A, the silica particles A, the polishing liquid composition B, the silica particles B, the polishing method and conditions, the cleaning composition, and the cleaning method, It can be the same as the manufacturing method of the magnetic disk substrate of the present disclosure described above.

  Regarding the above-described embodiment, the present disclosure further discloses the following composition, production method, or application.

<1> (1) A polishing composition A containing silica particles A, an acid, an oxidant, and water 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, and the polishing is performed. Moving the pad and / or the substrate to be polished to polish the surface to be polished;
(2) a step of cleaning the substrate obtained in step (1); and
(3) A polishing liquid composition B containing silica particles B and water is supplied to the polishing target surface of the substrate obtained in step (2), and the polishing pad is brought into contact with the polishing target surface, and the polishing pad and / or Or moving the substrate to be polished to polish the surface to be polished.
The steps (1) and (3) are performed by a separate polishing machine,
The silica particle A has non-spherical silica a having a ΔCV value of 10.0% or more and 30.0% or less and an average particle diameter (D1) of 50.0 nm or more and 125.0 nm or less, or a ΔCV value of 0. Non-spherical silica b having an average particle size (D1) of 120.0 nm or more and 300.0 nm or less;
The oxidizing agent is at least one selected from the group consisting of hydrogen peroxide, peroxodisulfate, and periodic acid and salts thereof;
When it does not contain periodic acid or its salt as the oxidizing agent, iron sulfate, iron nitrate, ammonium sulfate iron, iron perchlorate, iron chloride, iron citrate, ammonium iron citrate, iron oxalate, iron iron oxalate And at least one oxidation promoting aid selected from the group consisting of iron chelate complexes of ethylenediaminetetraacetic acid,
The ΔCV value is obtained by dividing the standard deviation based on the scattering intensity distribution at a detection angle of 30 ° by the dynamic light scattering method by the average particle diameter based on the scattering intensity distribution (CV30) and dynamic light. The difference (ΔCV = CV30−CV90) from the value obtained by dividing the standard deviation based on the scattering intensity distribution at a detection angle of 90 ° by the scattering method by the average particle diameter based on the scattering intensity distribution and multiplying by 100 (CV90). And the average particle diameter (D1) is an average particle diameter based on a scattering intensity distribution at a detection angle of 90 ° by a dynamic light scattering method.

<2> The method for producing a magnetic disk substrate according to <1>, wherein the polishing liquid composition A does not contain alumina abrasive grains.
<3> The method for producing a magnetic disk substrate according to <1> or <2>, wherein CV90 of the silica particles A is 10.0% or more and 40.0% or less.
<4> The non-spherical silica is such that the ratio (D1 / D2) of the average particle diameter (D1) by the dynamic light scattering method and the specific surface area converted particle diameter (D2) by the BET method is 1.50 or more and 4.00 or less. The method for producing a magnetic disk substrate according to any one of <1> to <3>, wherein the magnetic particles are silica particles satisfying at least.
<5> The non-spherical silica a is a non-spherical silica having a ΔCV value of 10.0% or more and 30.0% or less and an average particle diameter (D1) of 50 nm or more and 125 nm or less. <1> to <4 The method for producing a magnetic disk substrate according to any one of the above.
<6> The ΔCV value of the non-spherical silica a is preferably 10.0% or more, more preferably 11.0% or more, still more preferably 12.0% or more, and even more preferably 15.0% or more. And / or preferably 30.0% or less, more preferably 28.0% or less, even more preferably 25.0% or less, even more preferably 22.3% or less, from <1> to <5> The manufacturing method of the magnetic disc board | substrate in any one.
<7> The average particle diameter (D1) of the non-spherical silica a is preferably 50.0 nm or more, more preferably 60.0 nm or more, still more preferably 80.0 nm or more, and / or preferably 125.0 nm. Hereinafter, the method for producing a magnetic disk substrate according to any one of <1> to <6>, more preferably 123.0 nm or less, and further preferably 115.0 nm or less.
<8> The ratio (D1 / D2) of the average particle size (D1) of the non-spherical silica a by the dynamic light scattering method and the specific surface area converted particle size (D2) by the BET method is preferably 1.30 or more, more preferably Is 1.50 or more, more preferably 1.70 or more, and / or preferably 4.00 or less, more preferably 3.00 or less, still more preferably 2.50 or less, and even more preferably 2.05. The method for manufacturing a magnetic disk substrate according to any one of <1> to <7>, wherein:
<9> The non-spherical silica b is a non-spherical silica having a ΔCV value of 0.0% or more and less than 10.0% and an average particle diameter (D1) of 120.0 nm or more and 300.0 nm or less. > To <8>. A method of manufacturing a magnetic disk substrate according to any one of <8> to <8>.
<10> The ΔCV value of the non-spherical silica b is preferably 0.0% or more, more preferably 0.5% or more, still more preferably 1.0% or more, and / or preferably 10.0%. Less than, more preferably not more than 8.0%, still more preferably not more than 6.0%, or preferably not less than 0.0%, more preferably not less than 0.5%, still more preferably not less than 1.0%, Even more preferably 5.0% or more, even more preferably 6.0% or more, and / or preferably less than 10.0%, more preferably 9.0% or less, still more preferably 8.0%. The method for manufacturing a magnetic disk substrate according to any one of <1> to <9>, wherein:
<11> The average particle diameter (D1) of the non-spherical silica b is preferably 120.0 nm or more, more preferably 130.0 nm or more, still more preferably 150.0 nm or more, even more preferably 170.0 nm or more, and even more. Preferably it is 190.0 nm or more, and / or preferably 300.0 nm or less, more preferably 260.0 nm or less, still more preferably 220.0 nm or less, or preferably 120.0 nm or more, more preferably 121.0 nm or more, more preferably 122.0 nm or more, and / or preferably 300.0 nm or less, more preferably 250.0 nm or less, still more preferably 200.0 nm or less, even more preferably 150.0 nm or more. And even more preferably 135.0 nm or more, < The method for manufacturing a magnetic disk substrate according to any one of <1> to <10>.
<12> The ratio (D1 / D2) of the average particle diameter (D1) of the non-spherical silica b by the dynamic light scattering method and the specific surface area conversion particle diameter (D2) by the BET method is preferably 1.50 or more, more preferably Is 2.00 or more, more preferably 2.50 or more, even more preferably 3.00 or more, even more preferably 3.50 or more, and / or preferably 4.00 or less, more preferably 3. 90 or less, more preferably 3.80 or less, or preferably 1.50 or more, more preferably 1.80 or more, still more preferably 2.00 or more, even more preferably 2.40 or more, and / Or preferably 4.00 or less, more preferably 3.80 or less, even more preferably 3.50 or less, even more preferably 2.90 or less, even more preferably 2.70 or less. A method for manufacturing a magnetic disk substrate according to any one of <1> to <11>.
<13> The content of the silica particles A contained in the polishing composition A is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, further preferably 1% by mass or more, and still more preferably. 2% by weight or more, even more preferably 5% by weight or more, and / or preferably 30% by weight or less, more preferably 25% by weight or less, still more preferably 20% by weight or less, and even more preferably 15% by weight or less. The method of manufacturing a magnetic disk substrate according to any one of <1> to <12>, further preferably 10% by mass or less.
<14> The content of the oxidizing agent in the polishing composition A is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, and / or Alternatively, the method for producing a magnetic disk substrate according to any one of <1> to <13>, which is preferably 4% by mass or less, more preferably 2% by mass or less, and still more preferably 1.5% by mass or less.
<15> The content of the oxidation promoting aid in the polishing liquid composition A 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. And / or preferably 4.0% by mass or less, more preferably 2.0% by mass or less, and still more preferably 1.0% by mass or less, according to any one of <1> to <14>. A method for manufacturing a substrate.
<16> The pH of the polishing composition A is preferably 0.5 or more and 6.0 or less, and / or preferably 0.7 or more, more preferably 0.8 or more, and still more preferably 0.9. The magnetic disk substrate according to any one of <1> to <15>, and / or preferably having a pH of 4.0 or less, more preferably a pH of 3.0 or less, and even more preferably a pH of 2.0 or less. Production method.
<17> The silica particles B have an average particle diameter (D1) determined by a dynamic light scattering method of 1.0 nm or more and 40.0 nm or less, a ΔCV value of 0% or more and 10% or less, and CV90 of 10.0%. The method for producing a magnetic disk substrate according to any one of <1> to <16>, which is spherical silica of 35.0% or less.
<18> The average particle diameter (D1) of the silica particles B is preferably 1.0 nm or more, more preferably 5.0 nm or more, still more preferably 10.0 nm or more, and / or preferably 40.0 nm or less. More preferably, the magnetic disk substrate manufacturing method according to any one of <1> to <17>, which is 37.0 nm or less, and more preferably 35.0 nm or less.
<19> The method for producing a magnetic disk substrate according to any one of <1> to <18>, wherein the average particle diameter (D1) of the silica particles B is preferably smaller than the average particle diameter (D1) of the silica particles A.
<20> The ratio (D1 / D2) of the average particle diameter (D1) measured by the dynamic light scattering method of silica particles B to the specific surface area equivalent particle diameter (D2) by the BET method is preferably 1.00 or more. 1.50 or less, more preferably 1.00 or more and 1.40 or less, and even more preferably 1.00 or more and 1.30 or less, the magnetic disk substrate according to any one of <1> to <19> Manufacturing method.
<21> The ΔCV value of the silica particles B is preferably 0% to 10.0%, more preferably 0% to 8.0%, still more preferably 0% to 6.0%, and even more preferably. The magnetic disk substrate according to any one of <1> to <20>, which is 0% or more and 5.0% or less, and / or preferably 0.001% or more, more preferably 0.01% or more. Manufacturing method.
<22> The content of the silica particles B contained in the polishing composition B is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, further preferably 3.0% by mass or more, and even more. Preferably it is 4.0% by weight or more and / or preferably 20% by weight or less, more preferably 15% by weight or less, further preferably 10% by weight or less, more preferably 8% by weight or less, <1 > To <21> The method for producing a magnetic disk substrate according to any one of <21>.
<23> The method for producing a magnetic disk substrate according to any one of <1> to <22>, wherein the polishing compositions A and B have a pH of 0.5 or more and 6.0 or less.
<24> The method for producing a magnetic disk substrate according to any one of <1> to <23>, wherein the substrate to be polished is a Ni-P plated aluminum alloy substrate.
<25> (1) A polishing liquid composition A containing silica particles A, an acid, an oxidizing agent, and water 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, and the polishing is performed. Moving the pad and / or the substrate to be polished to polish the surface to be polished;
(2) a step of cleaning the substrate obtained in step (1); and
(3) A polishing liquid composition B containing silica particles B and water is supplied to the polishing target surface of the substrate obtained in step (2), and the polishing pad is brought into contact with the polishing target surface, and the polishing pad and / or Or moving the substrate to be polished to polish the surface to be polished.
The steps (1) and (3) are performed by a separate polishing machine,
The silica particle A has non-spherical silica a having a ΔCV value of 10.0% or more and 30.0% or less and an average particle diameter (D1) of 50.0 nm or more and 125.0 nm or less, or a ΔCV value of 0. Non-spherical silica b having an average particle size (D1) of 120.0 nm or more and 300.0 nm or less;
The oxidizing agent is at least one selected from the group consisting of hydrogen peroxide, peroxodisulfate, and periodic acid and salts thereof;
When it does not contain periodic acid or its salt as the oxidizing agent, iron sulfate, iron nitrate, ammonium sulfate iron, iron perchlorate, iron chloride, iron citrate, ammonium iron citrate, iron oxalate, iron iron oxalate And at least one oxidation promoting aid selected from the group consisting of iron chelate complexes of ethylenediaminetetraacetic acid,
The ΔCV value is obtained by dividing the standard deviation based on the scattering intensity distribution at a detection angle of 30 ° by the dynamic light scattering method by the average particle diameter based on the scattering intensity distribution (CV30) and dynamic light. The difference (ΔCV = CV30−CV90) from the value obtained by dividing the standard deviation based on the scattering intensity distribution at a detection angle of 90 ° by the scattering method by the average particle diameter based on the scattering intensity distribution and multiplying by 100 (CV90). The method for polishing a magnetic disk substrate, wherein the average particle size (D1) is an average particle size based on a scattering intensity distribution at a detection angle of 90 ° by a dynamic light scattering method.
<26> a first polishing machine for polishing a substrate to be polished using the polishing composition A;
A cleaning unit for cleaning the substrate polished by the first polishing machine;
A magnetic disk substrate polishing system comprising: a second polishing machine that polishes the substrate after cleaning with the polishing composition B;
The polishing composition A contains silica particles A, an acid, an oxidizing agent, and water,
The silica particle A has non-spherical silica a having a ΔCV value of 10.0% or more and 30.0% or less and an average particle diameter (D1) of 50.0 nm or more and 125.0 nm or less, or a ΔCV value of 0. Non-spherical silica b having an average particle size (D1) of 120.0 nm or more and 300.0 nm or less;
The oxidizing agent is at least one selected from the group consisting of hydrogen peroxide, peroxodisulfate, and periodic acid and salts thereof;
When it does not contain periodic acid or its salt as the oxidizing agent, iron sulfate, iron nitrate, ammonium sulfate iron, iron perchlorate, iron chloride, iron citrate, ammonium iron citrate, iron oxalate, iron iron oxalate And at least one oxidation promoting aid selected from the group consisting of iron chelate complexes of ethylenediaminetetraacetic acid,
A polishing system, wherein the polishing liquid composition B is a polishing liquid composition containing water and silica particles B.

  Hereinafter, the present disclosure will be described in more detail by way of examples. However, these examples are illustrative, and the present disclosure is not limited to these examples.

  Polishing liquid compositions A and B were prepared as described below, and the substrate to be polished including steps (1) to (3) was polished under the following conditions. The preparation method of the polishing liquid composition, the additive used, the measurement method of each parameter, the polishing conditions (polishing method) and the evaluation method are as follows.

1. Preparation of Polishing Liquid Composition A Abrasive grains in Table 1 (A-N: colloidal silica abrasive grains, O: fumed silica abrasive grains, P: ground silica abrasive grains, QR: alumina abrasive grains), sulfuric acid, oxidizing agent (Hydrogen peroxide, sodium peroxodisulfate, or orthoperiodic acid), oxidation promoter (use iron sulfate (II) heptahydrate only when the oxidizing agent is hydrogen peroxide) and water, Polishing liquid composition A was prepared (Examples 1-10, Comparative Examples 1-11, Tables 3 and 4). The content of each component in the polishing composition A is: abrasive grains: 8% by mass, sulfuric acid: 0.5-1.0% by mass, oxidizing agent: 0.5-1.0% by mass, oxidation promotion aid : 0.5% by mass. The pH of the polishing composition A was 1.0 to 1.4.

The types of silica abrasive grains in Table 1 are classifications that can be distinguished by a transmission electron microscope (TEM) observation photograph and analysis using the same in one or a plurality of embodiments.
“Konpeira type silica particles” refers to silica particles having unique ridge-like projections on the surface of spherical particles. In one or a plurality of embodiments, the confetti type silica particles refer to particles having a shape in which two or more particles different in particle size by 5 times or more are aggregated or fused.
“Deformed silica particles” refers to particles having a shape in which two or more particles are aggregated or fused.
“Spherical silica particles” refer to true spheres or spherical particles close to true spheres. Commonly commercially available colloidal silica is applicable.
"Beaded silica particles" refers to beads having a bead shape in which two or more particles having the same particle diameter are randomly connected at two or less contacts.
“High-purity mayu-type silica” refers to broad bean-like particles produced by the sol-gel method. Generally, high-purity silica that is commercially available is applicable.
“Fumed silica” refers to particles characterized by an elongated shape produced by a flame melting method.

  In addition, the non-spherical silicas a and b in Table 1 are silica particles produced by a particle growth method using an alkali silicate aqueous solution as a starting material.

  An example of an electron microscope (TEM) observation photograph of abrasive grain A (atypical silica: non-spherical silica a) in Table 1 is shown in FIG. 1, and an example of a TEM observation photograph of abrasive grain G (atypical silica: non-spherical silica b). Is shown in FIG.

2. Preparation of Polishing Liquid Composition B Using the colloidal silica abrasive grains (abrasive grains s) shown in Table 2 below, sulfuric acid, hydrogen peroxide, and water, polishing liquid composition B was prepared (Examples 1 to 10, Comparative Example 1). To 11, Tables 3 and 4). The content of each component in the polishing liquid composition B was colloidal silica particles: 5.0% by mass, sulfuric acid: 0.4% by mass, and hydrogen peroxide: 0.4% by mass. The pH of the polishing composition B was 1.4.

  An example of a TEM observation photograph of the abrasive grain s (spherical colloidal silica) is shown in FIG.

3. Measuring method of each parameter [Abrasive grains A to O and s average particle diameter (D1) and CV90 measured by dynamic light scattering method]
A standard sample was prepared by adding abrasive grains, sulfuric acid, and hydrogen peroxide to ion-exchanged water and mixing them. The contents of abrasive grains A to O, s, sulfuric acid, and hydrogen peroxide in the standard sample are 0.1 to 5.0 mass%, 0.2 to 0.4 mass%, and 0.2 to 0.4, respectively. It was mass%, and it adjusted suitably according to the type of the silica abrasive grain to be used. The area of the scattering intensity distribution obtained by the Marquardt method at a detection angle of 90 ° when this standard sample is integrated 200 times according to the instructions attached by the manufacturer using the dynamic light scattering device DLS-6500 manufactured by Otsuka Electronics Co., Ltd. The average particle diameter (D1) of the silica particles was determined. Further, the CV value (CV90) of the silica particles at a detection angle of 90 ° was calculated as a value obtained by dividing the standard deviation in the scattering intensity distribution measured according to the above measurement method by the average particle size and multiplying by 100.

[ΔCV value]
In the same manner as the CV90 measurement method, the CV value (CV30) of the silica particles at a detection angle of 30 ° was measured, and a value obtained by subtracting CV90 from CV30 was obtained to obtain the ΔCV value of silica particles A or B.
(Measurement conditions for DLS-6500)
Detection angle 90 °
Sampling time: 2-10 (μm) as appropriate Correlation Channel: 256-512 (ch) as appropriate Correlation Method: TI
Sampling temperature: 25.0 ° C
Detection angle 30 °
Sampling time: Adjusted appropriately at 4-20 (μm) Correlation Channel: Adjusted appropriately at 512-2048 (ch) Correlation Method: TI
Sampling temperature: 25 ° C

[Measurement of average secondary particle diameter of abrasive grains P to R]
A 0.5% “Poise 530” (polycarboxylic acid type polymer activator, manufactured by Kao Corporation) was used as a dispersion medium and placed in the following measuring device, and then the sample was adjusted so that the transmittance was 75 to 95%. After that, after applying ultrasonic waves for 5 minutes, the particle size was measured.
Measuring equipment: Laser diffraction / scattering type particle size distribution measuring instrument LA920 manufactured by HORIBA, Ltd.
Circulation strength: 4
Ultrasonic intensity: 4

4). Polishing conditions The substrate to be polished including steps (1) to (3) was polished. The conditions for each step are shown below. The step (1) was performed with the same polishing machine, and the step (3) was performed with a polishing machine separate from the polishing machine.
[Polished substrate]
The substrate to be polished was an aluminum alloy substrate plated with Ni-P. The substrate to be polished had a thickness of 1.27 mm and a diameter of 95 mm.

[Step (1): Rough polishing]
Polishing machine: Double-side polishing machine (9B-type double-side polishing machine, manufactured by Speed Fam Co., Ltd.)
Polishing liquid: Polishing liquid composition A (shown in Table 3)
Polishing pad: Suede type (foam layer: polyurethane elastomer), thickness 1.04mm, average pore diameter 43μm (FILWEL)
Lower platen rotation speed: 32.5 rpm
Polishing load: 9.8 kPa (set value)
Polishing liquid supply amount: 100 mL / min (0.076 mL / (cm ² · min))
Polishing time: 4 to 6 minutes (Examples and comparative examples in Table 3)
Polishing amount: 0.1 to 0.32 mg / (cm ² · min)
Number of substrates loaded: 10

[Step (2): Cleaning]
The substrate obtained in the step (2) was washed under the following conditions.
1. The substrate obtained in step (2) is immersed for 5 minutes in a bath containing an alkaline detergent composition having a pH of 12 consisting of a 0.1% by mass aqueous KOH solution.
2. The substrate after immersion is rinsed with ion exchange water for 20 seconds.
3. The rinsed substrate is transferred to a scrub cleaning unit in which a cleaning brush is set and cleaned.

[Step (3): Final polishing]
Polishing machine: Double-side polishing machine (9B type double-side polishing machine, manufactured by Speedfam), polishing machine separate from the polishing machine used in step (1): Polishing liquid composition B (shown in Table 3)
Polishing pad: Suede type (foam layer: polyurethane elastomer), thickness 1.0mm, average pore diameter 5μm (manufactured by FILWEL)
Lower platen rotation speed: 32.5 rpm
Polishing load: 7.9 kPa (set value)
Polishing liquid supply amount: 100 mL / min (0.076 mL / (cm ² · min))
Polishing time: 2 minutes Polishing amount: 0.04 to 0.10 mg / (cm ² · min)
Number of loaded substrates: 10 sheets After the step (3), cleaning was performed. The washing conditions were the same as in the above step (2).

  5. Evaluation method

[Measuring method of polishing amount and polishing rate in step (1)]
The weight of each substrate before and after the polishing in the step (1) and after the step (2) is measured (measured by Sartorius, “BP-210S”) and introduced into the following formula to obtain the polishing amount. It was.
Weight reduction (g) = {weight before polishing (g) −weight after polishing (g)}
Polishing amount (μm) = weight reduction amount (g) / substrate single-sided area (mm ² ) / 2 / Ni—P plating density (g / cm ³ ) × 10 ⁶
Polishing rate (mg / min) = (weight loss (g) / polishing time (min)) × 10 ³
(The substrate single-sided area is calculated as 6597 mm ² and Ni-P plating density 8.4 g / cm ³ )
The polishing time in the step (1) was 6 minutes (Examples 1 to 10, Comparative Examples 1 to 8) or 4 minutes (Comparative Examples 9 to 11).

[Method for evaluating protrusion defect after step (3)]
Measuring instrument: OSA7100 (manufactured by KLA Tencor)
Evaluation: The substrate polished with the polishing liquid composition B was immersed in ion-exchanged water for 5 minutes, and then rinsed with ion-exchanged water for 20 seconds. Then, 4 pieces were selected at random, and each substrate was irradiated with a laser at 10000 rpm to measure the number of abrasive sticks. The total number of abrasive piercings (pieces) on each of the four substrates was divided by 8 to calculate the number of abrasive piercings (number of protrusion defects) (pieces or relative value) per substrate surface.

[Evaluation method of substrate surface long wavelength waviness after steps (1) and (3)]
Step (1) or (3) Select any two of the 10 substrates after post-polishing, and measure both sides of each selected substrate at 120 ° for 4 points (16 points in total) under the following conditions: did. The average value of the 16 measured values was calculated as the swell of the substrate.
Equipment: Zygo NewView5032
Lens: 2.5x Michelson
Zoom ratio: 0.5
Remove: Cylinder
Filter: FFT Fixed Band Pass, Wave Wavelength: 0.5-5.0mm
Area: 4.33mm x 5.77mm

[Change rate of polishing rate and change rate of long wavelength waviness in step (1)]
In Examples 1 to 10 and Comparative Examples 1 to 8, in each composition, the rate of change with respect to the polishing rate and the long wavelength waviness when only the oxidizing agent in the polishing composition was used and no oxidation promoting aid was used (% ) Was calculated. If the rate of change is positive (+), it indicates that the value has increased, and if it is negative (−), it indicates that the value has decreased.

  The results of Examples 1 to 5 using non-spherical silica a (abrasive grains A to C) are shown in Table 3 below together with the results of Comparative Examples 1 to 11. Moreover, the result of Examples 6-10 using the non-spherical silica b (abrasive grains DG) is shown in following Table 4 with the result of Comparative Examples 1-11.

  As shown in Tables 3 and 4, in Examples 1 to 10, compared to Comparative Examples 1 to 8, a high polishing rate at a level that can be actually produced as a rough polishing step using silica particles in Step (1) can be obtained. The waviness (long wavelength waviness) on the substrate surface after the polishing in the step (1) and the step (3) could be reduced. Moreover, in Examples 1-10, the protrusion defect of the board | substrate after the grinding | polishing of a process (3) was able to be reduced compared with Comparative Examples 9-11.

  In addition, in Examples 1 to 10, the polishing rate in the case of selecting iron (II) sulfate heptahydrate as the oxidation promoting aid is higher than that in the case of using only hydrogen peroxide and Na peroxodisulfate as the oxidizing agent. It was confirmed that the improvement rate and the reduction rate of long wavelength waviness were particularly excellent. In particular, in polishing using silica particles as abrasive grains, the longer wavelength waviness of the substrate after polishing usually increases (deteriorates) when the polishing rate increases, but in Examples 1 to 10, although the polishing rate increases. In addition, the long wavelength waviness of the substrate after polishing was significantly reduced (improved).

Claims (8)

(1) A polishing liquid composition A containing silica particles A, an acid, an oxidizing agent, and water is supplied to the surface to be polished of the substrate to be polished, and the polishing pad is brought into contact with the surface to be polished, and the polishing pad and / or Or moving the substrate to be polished to polish the surface to be polished;
(2) a step of cleaning the substrate obtained in step (1); and
(3) A polishing liquid composition B containing silica particles B and water is supplied to the polishing target surface of the substrate obtained in step (2), and the polishing pad is brought into contact with the polishing target surface, and the polishing pad and / or Or moving the substrate to be polished to polish the surface to be polished.
The steps (1) and (3) are performed by a separate polishing machine,
The silica particle A has non-spherical silica a having a ΔCV value of 10.0% or more and 30.0% or less and an average particle diameter (D1) of 50.0 nm or more and 125.0 nm or less, or a ΔCV value of 0. Non-spherical silica b having an average particle size (D1) of 120.0 nm or more and 300.0 nm or less;
The oxidizing agent is at least one selected from the group consisting of hydrogen peroxide, peroxodisulfate, and periodic acid and salts thereof;
When it does not contain periodic acid or its salt as the oxidizing agent, iron sulfate, iron nitrate, ammonium sulfate iron, iron perchlorate, iron chloride, iron citrate, ammonium iron citrate, iron oxalate, iron iron oxalate And at least one oxidation promoting aid selected from the group consisting of iron chelate complexes of ethylenediaminetetraacetic acid,
The ΔCV value is obtained by dividing the standard deviation based on the scattering intensity distribution at a detection angle of 30 ° by the dynamic light scattering method by the average particle diameter based on the scattering intensity distribution (CV30) and dynamic light. The difference (ΔCV = CV30−CV90) from the value obtained by dividing the standard deviation based on the scattering intensity distribution at a detection angle of 90 ° by the scattering method by the average particle diameter based on the scattering intensity distribution and multiplying by 100 (CV90). And the average particle diameter (D1) is an average particle diameter based on a scattering intensity distribution at a detection angle of 90 ° by a dynamic light scattering method.   The method for producing a magnetic disk substrate according to claim 1, wherein the polishing liquid composition A does not contain alumina abrasive grains. The CV90 silica particles A is 40.0% or less 10.0% or more, a manufacturing method of a magnetic disk substrate according to claim 1 or 2. The silica particles B have an average particle size (D1) of 1.0 nm or more and 40.0 nm or less by a dynamic light scattering method, a ΔCV value of 0% or more and 10% or less, and a CV90 of 10.0% or more and 35. spherical silica is 2.0% or less, the manufacturing method of the magnetic disk substrate according to any one of claims 1 to 3. The pH of the polishing composition A and B is 0.5 to 6.0 The method of manufacturing a magnetic disk substrate according to any one of claims 1 to 4. The substrate to be polished, a Ni-P plating aluminum alloy substrate, a manufacturing method of a magnetic disk substrate in any one of claims 1 to 5. (1) A polishing liquid composition A containing silica particles A, an acid, an oxidizing agent, and water is supplied to the surface to be polished of the substrate to be polished, and the polishing pad is brought into contact with the surface to be polished, and the polishing pad and / or Or moving the substrate to be polished to polish the surface to be polished;
(2) a step of cleaning the substrate obtained in step (1); and
(3) A polishing liquid composition B containing silica particles B and water is supplied to the polishing target surface of the substrate obtained in step (2), and the polishing pad is brought into contact with the polishing target surface, and the polishing pad and / or Or moving the substrate to be polished to polish the surface to be polished.
The steps (1) and (3) are performed by a separate polishing machine,
The silica particle A has non-spherical silica a having a ΔCV value of 10.0% or more and 30.0% or less and an average particle diameter (D1) of 50.0 nm or more and 125.0 nm or less, or a ΔCV value of 0. Non-spherical silica b having an average particle size (D1) of 120.0 nm or more and 300.0 nm or less;
The oxidizing agent is at least one selected from the group consisting of hydrogen peroxide, peroxodisulfate, and periodic acid and salts thereof;
When it does not contain periodic acid or its salt as the oxidizing agent, iron sulfate, iron nitrate, ammonium sulfate iron, iron perchlorate, iron chloride, iron citrate, ammonium iron citrate, iron oxalate, iron iron oxalate And at least one oxidation promoting aid selected from the group consisting of iron chelate complexes of ethylenediaminetetraacetic acid,
The ΔCV value is obtained by dividing the standard deviation based on the scattering intensity distribution at a detection angle of 30 ° by the dynamic light scattering method by the average particle diameter based on the scattering intensity distribution (CV30) and dynamic light. The difference (ΔCV = CV30−CV90) from the value obtained by dividing the standard deviation based on the scattering intensity distribution at a detection angle of 90 ° by the scattering method by the average particle diameter based on the scattering intensity distribution and multiplying by 100 (CV90). The method for polishing a magnetic disk substrate, wherein the average particle size (D1) is an average particle size based on a scattering intensity distribution at a detection angle of 90 ° by a dynamic light scattering method. A first polishing machine for polishing a substrate to be polished using the polishing composition A;
A cleaning unit for cleaning the substrate polished by the first polishing machine;
A magnetic disk substrate polishing system comprising: a second polishing machine that polishes the substrate after cleaning with the polishing composition B;
The polishing composition A contains silica particles A, an acid, an oxidizing agent, and water,
The silica particle A has non-spherical silica a having a ΔCV value of 10.0% or more and 30.0% or less and an average particle diameter (D1) of 50.0 nm or more and 125.0 nm or less, or a ΔCV value of 0. Non-spherical silica b having an average particle size (D1) of 120.0 nm or more and 300.0 nm or less;
The oxidizing agent is at least one selected from the group consisting of hydrogen peroxide, peroxodisulfate, and periodic acid and salts thereof;
When it does not contain periodic acid or its salt as the oxidizing agent, iron sulfate, iron nitrate, ammonium sulfate iron, iron perchlorate, iron chloride, iron citrate, ammonium iron citrate, iron oxalate, iron iron oxalate And at least one oxidation promoting aid selected from the group consisting of iron chelate complexes of ethylenediaminetetraacetic acid,
A polishing system, wherein the polishing liquid composition B is a polishing liquid composition containing water and silica particles B.