JP2014130660A - Manufacturing method of magnetic disk substrate - Google Patents

Abstract

A method of manufacturing a magnetic disk substrate capable of reducing alumina sticking on a substrate after a rough polishing process is provided.
(1) A step of polishing a polishing target surface of a substrate to be polished using a polishing composition A containing alumina particles, silica particles and water, (2) a rinsing treatment of the substrate obtained in step 1 (3) The step of polishing the surface to be polished of the substrate obtained in step 2 using the polishing composition B containing silica particles and water, (4) The substrate obtained in step 3 is cleaned. And (5) polishing the surface to be polished of the substrate obtained in step 4 using the polishing composition C containing silica particles and water, and the steps 1 to 3 are the same polishing step. The total mass of the silica particles used in Steps 1 to 3 is the total of the alumina particles and the silica particles used in Steps 1 to 3. 65.0 mass% or more and 90.0 mass% or less of the magnetic disk with respect to the sum of mass Method of manufacturing a substrate.
[Selection figure] None

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. In order to increase the recording density, it is necessary to reduce the unit recording area and improve the detection sensitivity of the weakened magnetic signal. Therefore, technological development for lowering the flying height of the magnetic head has been advanced. ing. 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 employed (for example, Patent Document 1). 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 a rough polishing step) prior to the final polishing step, a polishing liquid composition containing alumina particles is used from the viewpoint of improving the polishing rate and improving the productivity. Moreover, in order to satisfy | fill the request | requirement of surface quality, the polishing liquid which mixed the silica particle with the alumina particle at the stage of rough polishing may be used (patent documents 2-3).

  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 substrate with a predetermined polishing load using a polishing liquid composition containing aluminum oxide particles (alumina particles) having an average secondary particle diameter of 0.1 to 0.7 μm and an acid. A method of manufacturing a magnetic disk substrate having a rough polishing step of polishing a substrate and a final polishing step of polishing the substrate obtained in the rough polishing step with a predetermined polishing amount using a polishing liquid composition containing colloidal particles is proposed. Has been. Moreover, the grinding | polishing method which grind | polishes using the alumina containing polishing liquid composition and the grinding | polishing which uses colloidal silica containing polishing liquid composition with the same grinder in the rough | crude grinding | polishing process is disclosed (patent documents 4-6).

JP-A-62-208869 JP 2006-518549 A JP 2005-186269 A JP 2012-25873 A JP 2012-43493 A JP 2006-95767 A

  With the increase in capacity of magnetic disk drives, the required characteristics for the surface quality of the substrate have become more stringent, and in the manufacturing process of the magnetic disk substrate, the residue of alumina particles on the substrate (for example, alumina sticking and protrusion defects) is further increased. There is a need to reduce it.

  Therefore, in one aspect, the present disclosure provides a method of manufacturing a magnetic disk substrate that can reduce alumina sticking on the substrate after the rough polishing step.

In one aspect, the present invention includes the following steps (1) to (5), the following steps (1) to (3) are performed by the same polishing machine, and the following step (5) is the polishing machine. The present invention relates to a method for manufacturing a magnetic disk substrate (hereinafter, also referred to as “manufacturing method according to the present disclosure”) performed by another polishing machine. Here, the total mass of the silica particles used in the steps (1) to (3) is 65.0 mass with respect to the sum of the total mass of the alumina particles and the silica particles used in the steps (1) to (3). % Or more and 90.0% by mass or less.
(1) A polishing liquid composition A containing alumina particles, silica particles, 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 object to be polished Polishing the surface to be polished by moving the substrate;
(2) A step of rinsing the substrate obtained in step (1),
(3) A polishing liquid composition B containing silica particles 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 Moving the substrate to be polished to polish the surface to be polished;
(4) A step of cleaning the substrate obtained in step (3),
(5) A polishing liquid composition C containing silica particles and water is supplied to the surface to be polished of the substrate obtained in step (4), the polishing pad is brought into contact with the surface to be polished, and / or the polishing pad and / or Moving the substrate to be polished to polish the surface to be polished;

In another aspect, the present invention includes the following steps (1) to (5), and the following steps (1) to (3) are performed with the same polishing machine, and the following step (5) is performed with the polishing machine. Relates to a method for polishing a magnetic disk substrate (hereinafter also referred to as “polishing method according to the present disclosure”) performed by another polishing machine. Here, the total mass of the silica particles used in the steps (1) to (3) is 65.0 mass with respect to the sum of the total mass of the alumina particles and the silica particles used in the steps (1) to (3). % Or more and 90.0% by mass or less.
(1) A polishing liquid composition A containing alumina particles, silica particles, 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 object to be polished Polishing the surface to be polished by moving the substrate;
(2) A step of rinsing the substrate obtained in step (1),
(3) A polishing liquid composition B containing silica particles 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 Moving the substrate to be polished to polish the surface to be polished;
(4) A step of cleaning the substrate obtained in step (3),
(5) A polishing liquid composition C containing silica particles and water is supplied to the surface to be polished of the substrate obtained in step (4), the polishing pad is brought into contact with the surface to be polished, and / or the polishing pad and / or Moving the substrate to be polished to polish the surface to be polished;

  According to the present disclosure, in one aspect, the substrate after the rough polishing step (step (1) to step (3)) is shortened and / or after the rough polishing step (step (1) to step (3)). It is possible to reduce the upper alumina stab, and the effect that a substrate with improved substrate quality can be manufactured with high productivity can be achieved.

  The present disclosure relates to a magnetic disk substrate manufacturing method including a rough polishing step and a final polishing step, wherein the rough polishing step is performed using a polishing liquid composition A containing alumina particles and water in the same polishing machine. In the configuration including the rough polishing, the rinsing process, and the second rough polishing using the polishing liquid composition B containing silica particles and water in this order, the abrasive particles of the polishing liquid composition A are used as alumina particles. In addition, by using silica particles so that the ratio of the total silica particles and alumina particles used in the rough polishing step is in a specific range, the total polishing time for rough polishing can be shortened and / or the substrate after the rough polishing step. This is based on the knowledge that the above alumina sticking can be reduced.

  In the present disclosure, “alumina piercing” means piercing of the alumina particles after polishing using alumina particles as an abrasive to the substrate. Further, in the present disclosure, “protrusion defect” refers to abrasive particles such as alumina remaining on a substrate and polishing scraps generated during polishing. The number of alumina sticks and / or protrusion defects can be evaluated by, for example, microscopic observation of a substrate surface obtained after polishing, scanning electron microscope observation, or a surface defect inspection apparatus.

  The reason why the total polishing time in the rough polishing step can be shortened by using the manufacturing method according to the present disclosure, the amount of alumina sticking after the rough polishing step is small, and the protrusion defects after the finish polishing step can be effectively reduced is not necessarily clear. However, it is estimated as follows. That is, when the silica particles coexist with the alumina particles in the polishing liquid composition A, the silica particles having a negative charge adhere to the alumina particles having a positive charge. This is considered to be because the alumina particles are prevented from being strongly pierced on the surface of the substrate to be polished, and it becomes easy to remove the piercing of alumina in polishing with the polishing composition B. The reason why the piercing of the alumina particles to which the silica particles are attached becomes shallow or weak may be an electrical repulsion force between the silica particles and the substrate surface and / or physical protection such as a cushioning action by the silica particles. On the other hand, it is predicted that the polishing time is more advantageous when more alumina particles are used, and it takes longer due to the coexistence of silica particles. However, by performing the rough polishing step in a setting in which the ratio of the total silica particles and alumina particles used in the rough polishing step of the present disclosure is in a specific range in which the total silica particles are larger than the alumina particles, for example, alumina particles The step (1) is completed in a short time with the polishing composition A contained at a relatively high rate, and then silica is used in the step (1) with the polishing composition B containing silica particles in the step (3). Thus, it can be estimated that the total polishing time of the rough polishing can be shortened by effectively removing the residual alumina whose piercing degree is shallower or weaker. Therefore, the silica particles coexist with the alumina particles in the polishing liquid composition A in the step (1), and the ratio of the total silica particles and the alumina particles used in the steps (1) to (3) is operated as a specific range. The total polishing time in the rough polishing step can be shortened, the alumina sticking on the substrate after the rough polishing step can be reduced, and the protrusion defects on the substrate after the final polishing step can be reduced. However, the present disclosure is not limited to these mechanisms.

  The manufacturing method according to the present disclosure will be described below. 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.

[Polished substrate]
The substrate to be polished in the manufacturing method according to the present disclosure is a magnetic disk substrate or a substrate used for a magnetic disk, such as a Ni-P plated aluminum alloy substrate, silicate glass, aluminosilicate glass, crystallized glass, and tempered glass. And the like. 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): First rough polishing]
In the production method according to the present disclosure, a polishing liquid composition A containing alumina particles, silica particles, 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 And / or a step of polishing the surface to be polished by moving the substrate to be polished (step (1)). 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 (2): Intermediate rinse treatment]
From the viewpoint of reducing alumina sticking on the substrate after the rough polishing process and from the viewpoint of reducing protrusion defects on the substrate after the final polishing process, the manufacturing method according to the present disclosure includes the same polishing machine after the step (1). The intermediate rinsing process (process (2)) for rinsing the substrate obtained in the process (1) is included. From the viewpoint of productivity, the intermediate rinse treatment is preferably performed in the same polishing machine without taking out the substrate to be polished from the polishing machine used in the step (1). In the step (2), specifically, the rinsing liquid composition 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 moved. And rinsing the surface to be polished. In addition, it is preferable that there is no washing | cleaning process like the washing | cleaning process (4) mentioned later between process (1) and (3). In the present disclosure, the “rinse treatment” refers to a treatment aimed at discharging abrasive grains and polishing debris remaining on the substrate surface. In order to flatten the substrate surface, the substrate surface is dissolved while the substrate surface is dissolved. This is a process different from a polishing process (chemical mechanical polishing) that uses a grain.

[Step (3): Second rough polishing]
The manufacturing method according to the present disclosure includes a polishing liquid composition B containing silica particles and water from the viewpoint of reducing alumina sticking on the substrate after the rough polishing step and reducing protrusion defects on the substrate after the final polishing step. Is supplied to the surface to be polished of the substrate obtained in the intermediate rinsing step (2), 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 moved to change the surface to be polished. A step of polishing (step (3)).

  From the viewpoints of shortening the total polishing time in the rough polishing process and reducing alumina sticking on the substrate after the rough polishing process and reducing protrusion defects on the substrate after the final polishing process, the steps (1) to (3) are the same. Perform with a polishing machine.

[Step (4): Washing]
The manufacturing method according to the present disclosure includes a step (step (4)) of cleaning the substrate obtained in step (3). In the cleaning in the step (4), it is preferable to clean the substrate on which the rough polishing step (steps (1) to (3)) has been performed using a cleaning composition. As a cleaning method in the step (4), for example, (a) a method of immersing the substrate obtained in the step (3) in a cleaning composition described later, and / or (b) injecting the cleaning composition. And a method of supplying a cleaning composition onto the surface of the substrate.

  In the 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 to 100 ° C. from the viewpoint of safety and operability. The immersion time is preferably 10 seconds to 30 minutes, and more preferably 2 to 20 minutes, from the viewpoints of cleanability and production efficiency with 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 to 2000 kHz, more preferably 30 to 1800 kHz, and still more preferably 40 to 1500 kHz.

  In the method (b), from the viewpoint of promoting the cleaning property of the residue and the solubility of the oil, the cleaning agent composition to which ultrasonic vibration is applied is injected and the cleaning agent composition is brought into contact with the surface of the substrate. The surface is washed or supplied by injecting the cleaning composition onto the surface of the substrate to be cleaned, and the surface supplied with the cleaning composition is cleaned by rubbing with a cleaning brush. It is preferable to do. 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. It is preferable to do.

  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 (4), in addition to the method (a) and / or the method (b), one or more steps using known cleaning such as swing cleaning, cleaning using rotation of a spinner, paddle cleaning, etc. May be included.

[Step (5): Final polishing]
In the production method according to the present disclosure, the polishing composition C containing silica particles and water is supplied to the surface to be polished of the substrate obtained in step (4), a polishing pad is brought into contact with the surface to be polished, A step of polishing the surface to be polished by moving a polishing pad and / or the substrate to be polished (step (5)).

  The polishing machine used in step (5) is used in steps (1) to (3) from the viewpoint of preventing alumina from being brought into the final polishing step and reducing protrusion defects on the substrate after the final polishing step. This is a separate grinder from the grinder.

  The manufacturing method according to the present disclosure includes the first rough polishing step (1), the intermediate rinse treatment step (2), the second rough polishing step (3), the cleaning step (4), and the finish polishing step. By including (5), the alumina piercing on the substrate after the rough polishing step is reduced, and the substrate on which the protrusion defects on the substrate after the final polishing step (defects derived from alumina piercing and polishing debris, etc.) are reduced is manufactured. can do.

[Total mass of silica particles used in steps (1) to (3)]
The total mass of the silica particles used in the rough polishing steps of steps (1) to (3) is the total polishing time shortened in the rough polishing step, the alumina piercing on the substrate after the rough polishing step, and the substrate after the final polishing. From the viewpoint of reducing protrusion defects, the amount is 65.0% by mass or more and 90.0% by mass or less with respect to the sum of the total mass of the alumina particles and the silica particles used in the steps (1) to (3). From the viewpoint of shortening the total polishing time in the rough polishing step, the total mass of the silica particles is preferably 88% by mass or less with respect to the sum of the total mass of the alumina particles and the silica particles used in the steps (1) to (3). More preferably, it is 85 mass% or less, 70 mass% or more is preferable, More preferably, it is 75 mass% or more. From the viewpoint of reducing alumina sticking on the substrate after the rough polishing step and protrusion defects on the substrate after the final polishing, the total mass of the silica particles is the same as the total mass of the silica particles in steps (1) to (3). Is preferably 78% by mass or less, more preferably 75% by mass or less, preferably 68% by mass or more, and more preferably 70% by mass or more with respect to the total mass of alumina particles and silica particles used in Or 88 mass% or less is preferable, 85 mass% or more is preferable, More preferably, it is 86 mass% or more. The total polishing time in the rough polishing step is considered to be due to the total amount of alumina particles added in the rough polishing step. The amount of piercing of alumina on the substrate after the rough polishing step is generally expected to decrease as the total mass of alumina particles added in the rough polishing step decreases, but the polishing composition A When the alumina concentration is relatively low, it takes a little longer time to ensure the surface quality by polishing the substrate, and when the polishing composition A has a relatively high alumina concentration, the surface quality is ensured by polishing the substrate. Therefore, the total amount of silica particles for reducing alumina sticking on the substrate after the rough polishing step is reduced because the polishing time in step (2) is lengthened to reduce the amount of alumina sticking. It is considered that there are a plurality of optimal regions. Therefore, it is considered that the effect of the present disclosure depends on various combinations of the balance of the polishing time in the step (1) and the step (2) and the balance of the alumina particles and the silica particles of the polishing liquid composition A. However, the present disclosure is not limited to these mechanisms. Here, the “total mass of silica particles used” is calculated from the supply amount of the polishing liquid compositions A and B supplied to the polishing machine and the content of the silica particles in the polishing liquid compositions A and B. Value. Similarly, the “total mass of alumina particles used” is a value calculated from the supply amount of the polishing liquid composition A supplied to the polishing machine and the content of alumina particles in the polishing liquid composition A. .

[Polishing time in step (1) and total polishing time in steps (1) to (3)]
In the present disclosure, the “total polishing time in steps (1) to (3)” refers to the sum of the polishing time in step (1), the rinsing time in step (2), and the polishing time in step (3). The polishing time in step (1) is from the viewpoint of reducing alumina sticking on the substrate after the rough polishing step, from the viewpoint of reducing protrusion defects on the substrate after the final polishing step, and from the viewpoint of shortening the polishing time. The total polishing time of (3) is preferably 25% or more and 75% or less. The polishing time in step (1) is from the viewpoint of reducing alumina sticking on the substrate after the rough polishing step, from the viewpoint of reducing protrusion defects on the substrate after the final polishing step, and from the viewpoint of shortening the polishing time. The total polishing time of (3) is preferably 25% or more, more preferably 30% or more, still more preferably 42% or more, and even more preferably 45% or more. The polishing time in step (1) is preferably 75% or less from the viewpoint of reducing alumina sticking on the substrate after the rough polishing step, from the viewpoint of reducing protrusion defects on the substrate after the final polishing step, and from the viewpoint of shortening the polishing time. More preferably, it is 60% or less, and further preferably 55% or less.

  The total polishing time of steps (1) to (3) is from the viewpoint of reducing alumina sticking on the substrate after the rough polishing step, from the viewpoint of reducing protrusion defects on the substrate after the final polishing step, and from the viewpoint of shortening the polishing time. It is preferably 3 minutes or more and 6 minutes or less. The total polishing time of steps (1) to (3) is from the viewpoint of reducing alumina sticking on the substrate after the rough polishing step, from the viewpoint of reducing protrusion defects on the substrate after the final polishing step, and from the viewpoint of shortening the polishing time. It is preferably 3 minutes or longer, more preferably 3.5 minutes or longer, and even more preferably 3.8 minutes or longer. The polishing time in the step (1) is preferably 6 minutes or less from the viewpoint of reducing alumina sticking on the substrate after the rough polishing step, from the viewpoint of reducing protrusion defects on the substrate after the final polishing step, and from the viewpoint of shortening the polishing time. More preferably, it is 5 minutes or less, More preferably, it is 4.3 minutes or less.

[Polishing pad of steps (1) to (3)]
There is no restriction | limiting in particular as a polishing pad used by the rough polishing process of process (1)-(3), Polishing pads, such as a suede type, a nonwoven fabric type, a polyurethane independent foam type, or the two-layer type which laminated | stacked these, are used. Although it can be used, 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. Alumina on the substrate after the rough polishing step is used. From the viewpoint of effectively reducing protrusion defects on the substrate after the piercing and finish polishing steps, 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.

  Moreover, the average pore diameter of the polishing pad used in the steps (1) to (3) is preferably 10 μm or more, more preferably 20 μm or more, further preferably 30 μm or more, and still more preferably, from the viewpoint of improving the polishing rate. From the same viewpoint, it is preferably 100 μm or less, more preferably 80 μm or less, still more preferably 60 μm or less, and even more preferably 55 μm or less.

[Polishing load in step (1)]
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 the step (1) is 25 kPa or less from the viewpoints of shortening the total polishing time in the rough polishing step and reducing alumina sticking on the substrate after the rough polishing step, and reducing protrusion defects on the substrate after the final polishing step. More preferably, it is 20 kPa or less, More preferably, it is 15 kPa or less, More preferably, it is 11 kPa or less. The polishing load is preferably 3 kPa or more, more preferably 5 kPa or more, still more preferably 7 kPa or more, and even more preferably 9 kPa or more from the viewpoint of improving the polishing rate. The polishing load can be adjusted by applying air pressure or weight to the surface plate or the substrate.

[Polishing amount in step (1)]
In the step (1), the polishing amount per unit area (1 cm ² ) of the substrate to be polished is the viewpoint of reducing plating defects, the viewpoint of reducing alumina sticking on the substrate after the rough polishing step, the substrate after the final polishing step From the viewpoint of reducing the above protrusion defects, 0.4 mg or more is preferable, more preferably 0.6 mg or more, and still more preferably 0.8 mg or more. On the other hand, from the viewpoint of improving productivity, 2.6 mg or less is preferable, more preferably 2.1 mg or less, and still more preferably 1.7 mg or less.

[Supply speed 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, more preferably 0.20 mL / min or less, more preferably 0.15 mL / min per 1 cm ^{2 of the} substrate to be polished, from the viewpoint of economy. More preferred is less than or equal to minutes. 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.

[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): Polishing load in intermediate rinsing process]
The polishing load in the step (2) is 25 kPa or less from the viewpoint of shortening the total polishing time in the rough polishing step and reducing alumina sticking on the substrate after the rough polishing step, and reducing protrusion defects on the substrate after the final polishing step. More preferably, it is 20 kPa or less, More preferably, it is 15 kPa or less, More preferably, it is 11 kPa or less. The polishing load is preferably 3 kPa or more, more preferably 5 kPa or more, still more preferably 7 kPa or more, and even more preferably 9 kPa or more from the viewpoint of improving the polishing rate. By setting the polishing load within the above range, it is considered that the pushing of alumina particles into the substrate is suppressed and the alumina sticking is effectively reduced.

[Rinse solution composition supply rate]
The supply speed of the rinsing liquid in the step (2) is 0.25 mL / min per 1 cm ^{2 of the} substrate to be polished from the viewpoint of reducing the alumina sticking on the substrate after the rough polishing step and the protrusion defect on the substrate after the final polishing step. The above is preferable, more preferably 0.8 mL / min or more, further preferably 1 mL / min or more, and from the same viewpoint, 4 mL / min or less per 1 cm ^{2 of the} substrate to be polished is preferable, more preferably 2.5 mL. / Min or less, more preferably 2 mL / min or less. In addition, the method of supplying the rinse liquid composition in the step (2) to the polishing machine can be performed in the same manner as the method of supplying the polishing liquid composition A described later to the polishing machine.

[Step (2): Intermediate rinse treatment time]
In the present disclosure, the processing time of the intermediate rinsing process refers to the supply time of the rinsing liquid composition. The processing time for the intermediate rinsing treatment is preferably 10 seconds or more, more preferably 15 from the viewpoint of reducing the alumina piercing on the substrate after the rough polishing step and the protrusion defect on the substrate after the final polishing step and productivity. 2 seconds or more, preferably 60 seconds or less, more preferably 40 seconds or less, and even more preferably 30 seconds or less.

[Polishing load in step (3)]
The polishing load in the step (3) is preferably 25 kPa or less, more preferably 20 kPa or less, more preferably from the viewpoint of reducing the alumina sticking on the substrate after the rough polishing step and the protrusion defect on the substrate after the final polishing step. 15 kPa or less, even more preferably 11 kPa or less. The polishing load is preferably 3 kPa or more, more preferably 5 kPa or more, still more preferably 7 kPa or more, and even more preferably 9 kPa or more from the viewpoint of improving the polishing rate. By setting the polishing load within the above range, it is considered that the pushing of alumina particles into the substrate is suppressed and the alumina sticking is effectively reduced.

[Polishing amount in step (3)]
In the step (3), the polishing amount per unit area (1 cm ² ) of the substrate to be polished is a viewpoint of reducing alumina sticking on the substrate after the rough polishing step, and a viewpoint of reducing protrusion defects on the substrate after the final polishing step. Therefore, 0.0004 mg or more is preferable, more preferably 0.004 mg or more, and still more preferably 0.01 mg or more. On the other hand, from the viewpoint of improving productivity, it is preferably 0.85 mg or less, more preferably 0.43 mg or less, further preferably 0.26 mg or less, and even more preferably 0.1 mg or less.

[Supply speed of polishing composition B]
The supply rate of the polishing composition B in the step (3) can be performed in the same manner as the supply rate of the polishing composition A described above.

[Method of supplying polishing liquid composition B to polishing machine]
The method for supplying the polishing liquid composition B to the polishing machine can be performed in the same manner as the method for supplying the polishing liquid composition A to the polishing machine. The polishing liquid composition B is different from the supply means for supplying the polishing liquid composition A from the viewpoint of reducing alumina sticking on the substrate after the rough polishing process and from the viewpoint of reducing the protrusion defects on the substrate after the final polishing process. It is preferable to supply from a supply means.

[Polishing pad in step (5)]
As the polishing pad used in the step (5), the same type of polishing pad as that used in the steps (1) to (3) may be used. The average pore diameter of the polishing pad used in the step (5) is preferably 1 μm or more, more preferably 2 μm or more, from the viewpoint of reducing protrusion defects, scratches, and surface roughness on the substrate after the final polishing step. Preferably, it is 3 μm or more, and from the same viewpoint, it is preferably 50 μm or less, more preferably 40 μm or less, still more preferably 30 μm or less, and even more preferably 10 μm or less.

[Polishing load in step (5)]
The polishing load in the step (5) is preferably 25 kPa or less, more preferably 20 kPa or less, still more preferably 15 kPa or less, and even more preferably 11 kPa or less, from the viewpoint of reducing protrusion defects on the substrate after the final polishing process. . In addition, the polishing load is preferably 3 kPa or more, more preferably 5 kPa or more, further preferably 7 kPa or more, and further preferably 9 kPa or more from the viewpoint of improving the polishing rate.

[Polishing amount in step (5)]
In the step (5), the polishing amount per unit area (1 cm ² ) of the substrate to be polished is preferably 0.085 mg or more from the viewpoint of reducing protrusion defects on the substrate after the final polishing step, and more preferably is 0.00. 1 mg or more, more preferably 0.13 mg or more, and even more preferably 0.15 mg or more. Moreover, from a viewpoint of productivity improvement, 0.85 mg or less is preferable, More preferably, it is 0.7 mg or less, More preferably, it is 0.5 mg or less, More preferably, it is 0.4 mg or less.

[Supply speed of polishing composition C]
The supply rate of the polishing composition C in the step (5) can be performed in the same manner as the supply rate of the polishing composition A described above.

[Method for supplying polishing composition C to polishing machine]
The method for supplying the polishing liquid composition C to the polishing machine can be performed in the same manner as the method for supplying the polishing liquid composition A to the polishing machine.

[Polishing liquid composition A]
The polishing composition A used in the step (1) contains alumina particles from the viewpoint of improving the polishing rate, reduces the alumina sticking on the substrate after the rough polishing step, and the substrate after the final polishing step. Silica particles are contained from the viewpoint of reducing the above protrusion defects.

[Polishing liquid composition A: alumina particles]
Examples of the alumina particles include α-alumina, intermediate alumina, amorphous alumina, and fumed alumina. From the viewpoint of improving the polishing rate, α-alumina is preferable, and the alumina piercing and finish polishing on the substrate after the rough polishing step. From the viewpoint of reducing protrusion defects on the substrate after the process, intermediate alumina is preferable.

  The average secondary particle diameter of the alumina particles is preferably 0.10 μm or more, more preferably 0.15 μm, from the viewpoint of reducing alumina sticking on the substrate after the rough polishing step and protrusion defects on the substrate after the final polishing step. Or more, more preferably 0.20 μm or more, even more preferably 0.25 μm or more, and from the same viewpoint, 0.80 μm or less is preferable, more preferably 0.75 μm or less, still more preferably 0.70 μm or less. Even more preferably, it is 0.60 μm or less, and still more preferably 0.50 μm or less. The average secondary particle diameter can be determined by the method described in the examples.

  The content of the alumina particles in the polishing liquid composition A is a viewpoint of shortening the total polishing time in the rough polishing process, and a viewpoint of reducing the protrusion of the alumina on the substrate after the rough polishing process and the protrusion defect on the substrate after the final polishing process. Therefore, 0.5% by mass or more is preferable, more preferably 0.8% by mass or more, still more preferably 1.0% by mass or more, and from the same viewpoint, 10% by mass or less is preferable, more preferably 5% by mass or less, more preferably 4% by mass or less, still more preferably 2.5% by mass or less, and even more preferably 1.5% by mass or less. In addition, the content of alumina particles in the entire abrasive contained in the polishing liquid composition A is the viewpoint of shortening the total polishing time in the rough polishing step, the alumina piercing on the substrate after the rough polishing step, and the substrate after the finish polishing step From the viewpoint of reducing the above protrusion defects, 10% by mass or more is preferable, 15% by mass or more is more preferable, 20% by mass or more is further preferable, 80% by mass or less is preferable, 60% by mass or less is more preferable, and 40% by mass. % Or less is more preferable.

[Α alumina]
In the present disclosure, α-alumina is a general term for crystalline alumina particles in which a structure peculiar to α-alumina is recognized in a crystal by X-ray diffraction. The structure unique to α-alumina is, for example, 2θ region 35.1 to 35.3 ° (104 plane), 43.2 to 43.4 ° (113 plane), 57.4 to 57.6 ° in the X-ray diffraction spectrum. This can be confirmed by the presence or absence of a peak having a vertex on (116 plane). In the present disclosure, unless specifically indicated, the α-alumina-specific peak means a peak on the 104 plane.

  The α-aluminization rate of the α-alumina is 50% or more from the viewpoint of shortening the total polishing time in the rough polishing step, reducing the alumina piercing on the substrate after the rough polishing step and the protrusion defect on the substrate after the final polishing step. It is preferably 60% or more, more preferably 63% or more, and from the same viewpoint, it is preferably 99% or less, more preferably 90% or less, and still more preferably 80% or less. is there. Here, the α conversion rate is 104 derived from 2θ = 35.1-35.3 ° in an X-ray diffraction method using WA-1000 (α alumina having an α conversion rate of 99.9%, manufactured by Showa Denko KK). The numerical value of the relative area of the α-alumina-specific peak when the peak area of the surface is 99.9% can be specifically obtained by the method described in the examples. In addition, a plurality of types of α-alumina having an α conversion rate within the above range may be used.

  The average secondary particle diameter of α-alumina is from the viewpoint of reducing the alumina sticking on the substrate after the rough polishing step and the protrusion defect on the substrate after the final polishing step, and from the viewpoint of shortening the total polishing time in the rough polishing step. 10 μm or more is preferable, more preferably 0.15 μm or more, still more preferably 0.20 μm or more, and even more preferably 0.25 μm or more. From the same viewpoint, 0.80 μm or less is preferable, and more preferably 0 .75 μm or less, more preferably 0.70 μm or less, even more preferably 0.60 μm or less, and even more preferably 0.50 μm or less. The average secondary particle diameter can be determined by the method described in the examples.

  The content of α-alumina in the polishing composition A is from the viewpoint of shortening the total polishing time in the rough polishing step, reducing the alumina piercing on the substrate after the rough polishing step, and the protrusion defects on the substrate after the final polishing step. 0.4% by mass or more, more preferably 0.5% by mass or more, still more preferably 0.6% by mass or more, still more preferably 0.7% by mass or more, and from the same viewpoint, 10 mass% or less is preferable, More preferably, it is 7.5 mass% or less, More preferably, it is 4 mass% or less, More preferably, it is 2 mass% or less, More preferably, it is 1 mass% or less.

[Intermediate alumina]
The polishing liquid composition A contains intermediate alumina from the viewpoint of shortening the total polishing time in the rough polishing process, from the viewpoint of reducing alumina sticking on the substrate after the rough polishing process and protrusion defects on the substrate after the final polishing process. It is preferable. Intermediate alumina is a general term for crystalline alumina particles other than α-alumina, and specifically includes γ-alumina, δ-alumina, θ-alumina, η-alumina, κ-alumina, and mixtures thereof. Among intermediate aluminas, γ alumina, δ alumina, θ alumina and these aluminas are used from the viewpoints of improving the polishing rate, reducing alumina sticking on the substrate after the rough polishing step, and reducing protrusion defects on the substrate after the final polishing step. A mixture is preferred, more preferably γ alumina and θ alumina, and still more preferably θ alumina.

  The average secondary particle diameter of the intermediate alumina is from the viewpoint of shortening the total polishing time in the rough polishing process, from the viewpoint of reducing the alumina sticking on the substrate after the rough polishing process and the protrusion defect on the substrate after the final polishing process. 01 μm or more is preferable, more preferably 0.05 μm or more, still more preferably 0.10 μm or more, and even more preferably 0.12 μm or more. From the same viewpoint, 0.6 μm or less is preferable, and more preferably 0 0.5 μm or less, more preferably 0.4 μm or less, even more preferably 0.3 μm or less, and even more preferably 0.2 μm or less. The average secondary particle diameter can be determined by the same method as in the case of the aforementioned α-alumina.

  Further, the content of the intermediate alumina in the polishing liquid composition A is reduced in terms of reducing the alumina sticking on the substrate after the rough polishing step and the protrusion defects on the substrate after the final polishing step, and shortening the total polishing time in the rough polishing step. In view of the above, 0.05% by mass or more is preferable, more preferably 0.1% by mass or more, still more preferably 0.2% by mass or more, and still more preferably 0.5% by mass or more. From the viewpoint, it is preferably 3% by mass or less, more preferably 1% by mass or less, still more preferably 0.8% by mass or less, still more preferably 0.6% by mass or less, and even more preferably 0.4% by mass or less. is there.

  The polishing composition A is used as alumina particles from the viewpoint of shortening the total polishing time in the rough polishing process, and from the viewpoint of reducing alumina sticking on the substrate after the rough polishing process and protrusion defects on the substrate after the final polishing process. It is preferable to contain α-alumina and intermediate alumina, and more preferably α-alumina and θ-alumina.

  When α alumina and intermediate alumina are used, the mass ratio of α alumina to intermediate alumina (mass% of α alumina / mass% of intermediate alumina) is determined in view of shortening the total polishing time in the rough polishing process. 90/10 to 10/90 is preferable, more preferably 85/15 to 40/60, and still more preferably 80/20 to 90% from the viewpoint of reducing the alumina piercing on the substrate and the protrusion defect on the substrate after the finish polishing step. 70/30.

[Polishing liquid composition A: silica particles]
Polishing liquid composition A further contains silica particles from the viewpoint of reducing alumina sticking on the substrate after the rough polishing step and from the viewpoint of reducing protrusion defects on the substrate after the final polishing step. Examples of the silica particles include colloidal silica, fumed silica, and surface-modified silica. Among these, colloidal silica is preferable from the viewpoint of reducing alumina sticking on the substrate after the rough polishing step and protrusion defects on the substrate after the final polishing step.

  The average primary particle size (D50) of the silica particles is from the viewpoint of reducing alumina sticking on the substrate after the rough polishing step and protrusion defects on the substrate after the final polishing step, and from the viewpoint of shortening the total polishing time in the rough polishing step. , Preferably 15 nm or more, more preferably 30 nm or more, further preferably 40 nm or more, and from the same viewpoint, preferably 120 nm or less, more preferably 100 nm or less, still more preferably 80 nm or less, and even more preferably 75 nm or less. Even more preferably, it is 60 nm or less. In addition, this average primary particle diameter can be calculated | required by the method as described in an Example.

  In addition, the standard deviation of the primary particle diameter of the silica particles is a viewpoint of reducing alumina sticking on the substrate after the rough polishing process and a protrusion defect on the substrate after the final polishing process, and a viewpoint of shortening the total polishing time in the rough polishing process. Therefore, it is preferably 8 nm or more, more preferably 20 nm or more, even more preferably 30 nm or more, and even more preferably 35 nm or more. From the same viewpoint, it is preferably 80 nm or less, more preferably 70 nm or less, and even more preferably Is 60 nm or less, and more preferably 55 nm or less. In addition, this standard deviation can be calculated | required by the method as described in an Example.

  The primary particle diameter (D10) of the silica particles is from the viewpoint of reducing the alumina piercing on the substrate after the rough polishing step and the protrusion defect on the substrate after the final polishing step, and from the viewpoint of shortening the total polishing time in the rough polishing step. Preferably it is 5 nm or more, More preferably, it is 10 nm or more, More preferably, it is 20 nm or more, Moreover, from the same viewpoint, Preferably it is 60 nm or less, More preferably, it is 40 nm or less, More preferably, it is 30 nm or less. In addition, this primary particle diameter (D10) can be calculated | required by the method as described in an Example.

  The primary particle diameter (D90) of the silica particles is from the viewpoint of reducing the alumina sticking on the substrate after the rough polishing step and the protrusion defects on the substrate after the final polishing step, and from the viewpoint of shortening the total polishing time in the rough polishing step. Preferably it is 40 nm or more, more preferably 60 nm or more, more preferably 70 nm or more, and from the same viewpoint, it is preferably 150 nm or less, more preferably 120 nm or less, still more preferably 100 nm or less, and even more preferably 85 nm or less. is there. In addition, this primary particle diameter (D90) can be calculated | required by the method as described in an Example.

  The mass ratio of alumina particles to silica particles (alumina particle mass / silica particle mass) in the polishing liquid composition A is a reduction in total polishing time in the rough polishing process and a reduction in alumina sticking on the substrate after the rough polishing process. From the viewpoint of reducing protrusion defects on the substrate after the process, it is preferably 80/20 to 10/90, more preferably 60/40 to 15/85, and further preferably 40/60 to 20/80.

  The ratio of the average secondary particle diameter of alumina particles to the average primary particle diameter (D50) of silica particles (alumina particle diameter / silica particle diameter) is the total polishing time shortened in the rough polishing step and on the substrate after the rough polishing step. From the viewpoint of reducing alumina piercing, and from the viewpoint of reducing protrusion defects on the substrate after the final polishing step, it is preferably 1 or more, more preferably 2 or more, still more preferably 5 or more, and from the same viewpoint, preferably 100. Below, more preferably 50 or less, still more preferably 10 or less, and even more preferably 7 or less.

  The content of silica particles contained in the polishing liquid composition A is 0.3% by mass or more from the viewpoint of reducing alumina sticking on the substrate after the rough polishing step and protrusion defects on the substrate after the final polishing step. More preferably, it is 0.5 mass% or more, More preferably, it is 1.5 mass% or more, More preferably, it is 2.5 mass% or more. The content is preferably 20% by mass or less, more preferably 15% by mass or less, still more preferably 10% by mass or less, and still more preferably 5% from the viewpoint of economy and reduction of the total polishing time in the rough polishing process. It is below mass%.

[Polishing liquid composition A: acid]
The polishing composition A preferably contains an acid from the viewpoint of improving the polishing rate, reducing the alumina sticking on the substrate after the rough polishing step, and reducing the protrusion defects on the substrate after the final polishing step. 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-1,1,2-triphosphonic acid, ethane-1,2-dicarboxy-1,2-diphosphonic acid, methanehydroxyphosphonic acid, 2-phosphonobutane-1,2 -Dicarboxylic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid, α-methylphosphonoco Organic phosphonic acids such as click acid, glutamic acid, picolinic acid, amino acids such as aspartic acid, citric acid, tartaric acid, oxalic acid, nitro acid, maleic acid, and carboxylic acids such as oxaloacetic acid. Among these, phosphoric acid, sulfuric acid, citric acid, tartaric acid, maleic acid, 1-hydroxy, from the viewpoint of improvement of polishing rate, alumina sticking on the substrate after the rough polishing step, and reduction of protrusion defects on the substrate after the final polishing step Ethylidene-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid) and their salts are more preferred, and sulfuric acid, citric acid and their salts are more preferred. .

  These acids and salts thereof may be used alone or in admixture of two or more. However, the polishing rate is improved, the alumina sticks on the substrate after the rough polishing step, and the protrusion defect on the substrate after the final polishing step. It is preferable to use a mixture of two or more types from the viewpoint of reducing the amount of phosphoric acid, sulfuric acid, citric acid, tartaric acid and 1-hydroxyethylidene-1,1-diphosphonic acid. It is more preferable to use an acid, and it is more preferable to use sulfuric acid and citric acid.

  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, a salt with a metal belonging to Group 1A or ammonium is preferable from the viewpoint of availability.

  The content of the acid in the polishing composition A is 0.001 mass from the viewpoint of improving the polishing rate, reducing alumina sticking on the substrate after the rough polishing step, and reducing protrusion defects on the substrate after the final polishing step. % Or more, more preferably 0.01% by mass or more, further preferably 0.1% by mass or more, and from the same viewpoint, 5% by mass or less is preferable, more preferably 4% by mass or less, and further Preferably it is 3 mass% or less, More preferably, it is 2 mass% or less, More preferably, it is 1.5 mass% or less.

[Polishing liquid composition A: oxidizing agent]
The polishing composition A preferably contains an oxidizing agent from the viewpoint of improving the polishing rate, reducing the alumina sticking on the substrate after the rough polishing step, and reducing the protrusion defects on the substrate after the final polishing step. As the oxidizing agent, from the viewpoint of reducing the polishing rate and the alumina sticking on the substrate after the rough polishing step and the protrusion defect on the substrate after the final polishing step, peroxide, permanganic acid or a salt thereof, chromic acid or the Examples thereof include salts, peroxo acids or salts thereof, oxygen acids or salts thereof, and metal salts. 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.

  The content of the oxidizing agent in the polishing composition A is preferably from the viewpoint of improving the polishing rate, and reducing the alumina piercing on the substrate after the rough polishing step and the protrusion defect on the substrate after the final polishing step. Is 0.01% by mass or more, more preferably 0.05% by mass or more, further preferably 0.1% by mass or more, and from the same viewpoint, preferably 4% by mass or less, more preferably 2% by mass. Hereinafter, it is more preferably 1.5% by mass or less, and still more preferably 1% by mass or less.

[Polishing liquid composition A: 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 61% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, even more because the handling of the polishing liquid composition becomes easy. Preferably, it is 85 mass% or more, and from the same viewpoint, 99 mass% or less is preferable, More preferably, it is 98 mass% or less, More preferably, it is 97 mass% or less.

[Polishing liquid composition A: other components]
In the polishing composition A, other components can be blended as necessary. Examples of other components include thickeners, dispersants, rust inhibitors, basic substances, surfactants, cationic polymers such as diallylamine polymers and polyethyleneimines. 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 10% by mass or less, and more preferably 5% by mass or less.

[Polishing liquid composition A: pH]
From the viewpoint of improving the polishing rate, and the pH of the polishing composition A from the viewpoint of reducing the alumina sticking on the substrate after the rough polishing step and the protrusion defects on the substrate after the final polishing step, the above-mentioned acids and known ones are known. Is preferably adjusted to pH 1.0 to 6.0, more preferably pH 1.0 to 4.0, still more preferably pH 1.0 to 3.0, and even more preferably pH 1. 0-2.0. 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.

[Polishing liquid composition A: Preparation method]
The polishing liquid composition A can be prepared, for example, by mixing alumina particles, silica particles and water, and, if desired, an oxidizing agent, an acid and other components by a known method. When mixing silica particles, they may be mixed in a concentrated slurry, or may be mixed after being diluted with water or the like. 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.

[Rinse composition used for intermediate rinsing]
The rinse liquid composition used for the intermediate rinse treatment in the step (2) contains water. In one or some embodiment, water, such as distilled water, ion-exchange water, a pure water, and an ultrapure water, may be used for the rinse liquid composition from the point of manufacturing cost.

  The rinsing liquid composition has a nonionic surface active activity from the viewpoint of shortening the total polishing time in the rough polishing process and reducing alumina sticking on the substrate after the rough polishing process, and reducing protrusion defects on the substrate after the final polishing process. Agents, anionic surfactants, water-soluble polymers, chelating agents, alcohols, preservatives, antioxidants and the like may be contained.

[Polishing liquid composition B]
The polishing composition B used in the step (3) contains silica particles and water from the viewpoint of reducing alumina sticking on the substrate after the rough polishing step and protrusion defects on the substrate after the final polishing step. The silica particles used are the same as the silica particles used in the polishing composition A, and are preferably colloidal silica.

[Polishing liquid composition B: silica particles]
The average primary particle diameter (D50) of the silica particles used in the polishing liquid composition B is a viewpoint of reducing alumina sticking on the substrate after the rough polishing step and protrusion defects on the substrate after the final polishing step, and the rough polishing step. From the viewpoint of shortening the total polishing time, the thickness is preferably 15 nm or more, more preferably 30 nm or more, further preferably 40 nm or more, and from the same viewpoint, preferably 120 nm or less, more preferably 100 nm or less, and further preferably 80 nm. Hereinafter, it is still more preferably 75 nm or less, and still more preferably 60 nm or less. When the average primary particle diameter (D50) of the silica particles is within the above range, it is considered that the frictional force at the time of polishing cutting is increased, and alumina sticking is effectively reduced. In addition, this average primary particle diameter can be calculated | required by the method as described in an Example.

  Further, the standard deviation of the primary particle diameter of the silica particles used in the polishing liquid composition B is the viewpoint of reducing the alumina sticking on the substrate after the rough polishing step and the protrusion defect on the substrate after the final polishing step, and the rough polishing. From the viewpoint of shortening the total polishing time in the process, it is preferably 8 nm or more, more preferably 20 nm or more, even more preferably 30 nm or more, even more preferably 35 nm or more, and from the same viewpoint, preferably 80 nm or less, more Preferably it is 70 nm or less, More preferably, it is 60 nm or less, More preferably, it is 55 nm or less. When the standard deviation of the primary particle diameter is within the above range, the frictional force at the time of polishing and cutting is further improved, the alumina particles stuck in the step (1) are efficiently pulled out, and the alumina sticking is reduced. Conceivable. In addition, this standard deviation can be calculated | required by the method as described in an Example.

  The primary particle diameter (D10) of the silica particles used in the polishing liquid composition B is the viewpoint of reducing the alumina sticking on the substrate after the rough polishing step and the protrusion defect on the substrate after the final polishing step, and the rough polishing step. From the viewpoint of shortening the total polishing time, it is preferably 5 nm or more, more preferably 10 nm or more, further preferably 20 nm or more, and from the same viewpoint, preferably 60 nm or less, more preferably 40 nm or less, and further preferably 30 nm or less. It is. In addition, this primary particle diameter (D10) can be calculated | required by the method as described in an Example.

  The primary particle diameter (D90) of the silica particles used in the polishing liquid composition B is the viewpoint of reducing the alumina sticking on the substrate after the rough polishing step and the protrusion defect on the substrate after the final polishing step, and the rough polishing step. From the viewpoint of shortening the total polishing time, it is preferably 40 nm or more, more preferably 60 nm or more, further preferably 70 nm or more, and from the same viewpoint, preferably 150 nm or less, more preferably 120 nm or less, and further preferably 100 nm or less. Even more preferably, it is 85 nm or less. In addition, this primary particle diameter (D90) can be calculated | required by the method as described in an Example.

  The content of the silica particles contained in the polishing liquid composition B is reduced in the total polishing time in the rough polishing step and in reducing the alumina sticking on the substrate after the rough polishing step, and in reducing the protrusion defects on the substrate after the final polishing step. From a viewpoint, 0.3 mass% or more is preferable, 0.5 mass% or more is more preferable, 1 mass% or more is further more preferable, and 2 mass% or more is further more preferable. Further, the content is preferably 20% by mass or less, more preferably 15% by mass or less, further preferably 10% by mass or less, and still more preferably 6% by mass or less from the viewpoint of economy.

  Further, the content of silica particles in the entire polishing material contained in the polishing composition B is reduced in the total polishing time in the rough polishing step and the alumina sticking on the substrate after the rough polishing step, and after the finish polishing step. From the viewpoint of reducing protrusion defects on the substrate, 60% by mass or more is preferable, 80% by mass or more is more preferable, 90% by mass or more is further preferable, and 100% by mass is even more preferable. The content of alumina particles in the entire abrasive contained in the polishing composition B is 40 from the viewpoint of reducing the alumina sticking on the substrate after the rough polishing step and the protrusion defects on the substrate after the final polishing step. % By mass or less, more preferably 20% by mass or less, still more preferably 10% by mass or less, still more preferably substantially no alumina particles, and even more preferably no alumina particles. In the present disclosure, “does not contain alumina” means that in one or a plurality of embodiments, it does not contain alumina particles, substantially does not 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 preferably 5% by mass or less, more preferably 2% by mass or less, still more preferably 1% by mass or less, and still more preferably 0%.

  The polishing liquid composition B contains an acid and an oxidant from the viewpoint of shortening the total polishing time in the rough polishing step and reducing alumina sticking on the substrate after the rough polishing step, and reducing protrusion defects on the substrate after the final polishing step. It is preferable to contain. The preferred embodiments of the acid and the oxidizing agent are the same as in the case of the polishing composition A described above, and the acid is preferably sulfuric acid. Further, water used for the polishing liquid composition B, other components, the pH of the polishing liquid composition B, and a preferred embodiment of the method for preparing the polishing liquid composition B are also the same as in the case of the polishing liquid composition A described above.

[Polishing liquid composition C]
Polishing liquid composition C used at a process (5) contains a silica particle from a viewpoint of reducing the projection defect on the board | substrate after a final polishing process, and a viewpoint of a polishing rate improvement. The silica particles used are the same as the silica particles used in the polishing composition B, and are preferably colloidal silica. Moreover, it is preferable not to contain alumina particles from the viewpoint of reducing protrusion defects on the substrate after the finish polishing step.

  The average primary particle diameter (D50) of the silica particles used in the polishing liquid composition C is preferably 5 nm or more, more preferably 10 nm or more, more preferably from the viewpoint of reducing protrusion defects on the substrate after the final polishing step. Preferably, it is 15 nm or more, more preferably 20 nm or more, and from the same viewpoint, it is preferably 120 nm or less, more preferably 100 nm or less, still more preferably 50 nm or less, and even more preferably 40 nm or less. In addition, this average primary particle diameter can be calculated | required by the method as described in an Example.

  In addition, the standard deviation of the primary particle diameter of the silica particles is preferably 8 nm or more, more preferably 10 nm or more, and further preferably 15 nm or more, from the viewpoint of reducing protrusion defects on the substrate after the finish polishing step. From the same viewpoint, it is preferably 80 nm or less, more preferably 50 nm or less, further preferably 30 nm or less, and even more preferably 25 nm or less. In addition, this standard deviation can be calculated | required by the method as described in an Example.

  The primary particle diameter (D10) of the silica particles is preferably 5 nm or more, more preferably 10 nm or more, and still more preferably 15 nm, from the viewpoint of reducing protrusion defects on the substrate after the final polishing step and improving the polishing rate. As described above, it is more preferably 20 nm or more, and from the same viewpoint, it is preferably 80 nm or less, more preferably 50 nm or less, and further preferably 40 nm or less. In addition, this primary particle diameter (D10) can be calculated | required by the method as described in an Example.

  The primary particle diameter (D90) of the silica particles is preferably 10 nm or more, more preferably 15 nm or more, and further preferably 20 nm, from the viewpoint of reducing protrusion defects on the substrate after the final polishing process and from the viewpoint of improving the polishing rate. As described above, it is more preferably 25 nm or more, and from the same viewpoint, it is preferably 150 nm or less, more preferably 80 nm or less, and further preferably 40 nm or less. In addition, this primary particle diameter (D90) can be calculated | required by the method as described in an Example.

  The content of the silica particles contained in the polishing composition C is preferably 0.5% by mass or more, more preferably 1% by mass or more, from the viewpoint of reducing protrusion defects on the substrate after the final polishing step, and 3% by mass. % Or more is more preferable, 4% by mass or more is further more preferable, and from the same viewpoint, 20% by mass or less is preferable, 15% by mass or less is more preferable, 10% by mass or less is further preferable, and 8% by mass or less is preferable. Even more preferred.

[Polishing liquid composition C: other components]
In the polishing composition C, other components can be blended as necessary. Examples of other components include acids, oxidants, thickeners, dispersants, rust inhibitors, basic substances, surfactants, heterocyclic compounds, nitrogen-containing compounds, and anionic polymers. The content of these other optional components in the polishing liquid composition C is preferably blended within a range not impairing the effects of the present disclosure, preferably 10% by mass or less, and more preferably 5% by mass or less.

  The polishing composition C preferably contains an acid and an oxidizing agent from the viewpoint of improving the polishing rate and from the viewpoint of reducing protrusion defects on the substrate after the final polishing step. About the preferable usage aspect of an acid and an oxidizing agent, it is the same as that of the case of the above-mentioned polishing liquid composition A, and also sulfuric acid is preferable as an acid. Further, water and other components used in the polishing liquid composition C, the pH of the polishing liquid composition C, and a preferred embodiment of the method for preparing the polishing liquid composition C are the same as in the case of the polishing liquid composition A described above.

  The polishing composition C preferably contains at least one selected from a heterocyclic compound, a nitrogen-containing compound, and an anionic polymer from the viewpoint of reducing protrusion defects on the substrate after the final polishing step. It is more preferable to contain at least species, and it is more preferable to contain a heterocyclic compound, a nitrogen-containing compound, and an anionic polymer.

[Cleaning composition]
In the cleaning in the step (4), it is preferable to use a cleaning composition. As said cleaning composition, what contains an alkaline agent, water, and various additives as needed can be used.

[Alkaline agent]
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 0.1% by mass or more, and from the same viewpoint, it is preferably 10% by mass or less, and more preferably 3% by mass or less.

  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. Also, from the same viewpoint, it is preferably 13 or less. In addition, said pH is pH of the cleaning composition at 25 degreeC, can be measured using a pH meter (Toa Denpa Kogyo Co., Ltd., HM-30G), and 40 minutes after immersing an electrode in cleaning composition It is the latter number.

[Various additives]
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 cleaning composition is used after being diluted. In consideration of cleaning efficiency, the dilution rate is preferably 10 times or more, more preferably 20 times or more, and further preferably 50 times or more, and from the same viewpoint, preferably 500 times or less, more preferably 200 times. Hereinafter, it is more preferably 100 times or less. The water for dilution may be the same as the above-mentioned polishing composition.

  According to the manufacturing method according to the present disclosure, it is possible to reduce the total polishing time in the rough polishing step, and the magnetic disk in which the alumina sticking on the substrate after the rough polishing step and the protrusion defects on the substrate after the final polishing step are reduced. Since a substrate can be provided, it can be suitably used for polishing a perpendicular magnetic recording type magnetic disk substrate that requires a high degree of surface smoothness.

[Polishing method]
As another aspect, the present disclosure further includes the following steps (1) to (5), the following steps (1) to (3) are performed by the same polishing machine, and the following step (5) is performed by the polishing machine. The total mass of silica particles used in steps (1) to (3) is the sum of the total mass of alumina particles and silica particles used in steps (1) to (3). The present invention relates to a method for polishing a magnetic disk substrate, which is 65.0 mass% or more and 90.0 mass% or less.
(1) A polishing liquid composition A containing alumina particles, silica particles, 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 object to be polished A step of polishing the surface to be polished by moving the substrate, (2) a step of rinsing the substrate obtained in step (1), (3) polishing composition B containing silica particles and water in step (2) (4) supplying the polishing target surface of the substrate obtained in (1) above, bringing a polishing pad into contact with the polishing target surface, and moving the polishing pad and / or the polishing target substrate to polish the polishing target surface; A step of washing the substrate obtained in step (3), (5) supplying a polishing composition C containing silica particles and water to the surface to be polished of the substrate obtained in step (4), and A polishing pad in contact with the surface, and the polishing pad and / Or polishing the surface to be polished by moving the substrate to be polished.

  In addition, about the to-be-polished substrate, the polishing pad, the composition of the polishing liquid compositions A to C, the rinsing treatment method, the cleaning agent composition, and the polishing method and conditions in the polishing method according to the present disclosure, the above-described present disclosure. It can be the same as that of the manufacturing method concerning.

  According to the polishing method according to the present disclosure, it is possible to efficiently manufacture a substrate with reduced alumina piercing on the substrate after the rough polishing step and protrusion defects on the substrate after the finish polishing step, and to reduce the product yield. It is possible to produce a magnetic disk substrate with improved substrate quality and with good productivity.

  By using the polishing method according to the present disclosure, the quality of the magnetic disk substrate, particularly the perpendicular magnetic recording system, is improved by reducing the number of alumina stabs on the substrate after the rough polishing step and the protrusion defects on the substrate after the final polishing step. A magnetic disk substrate is preferably provided. Examples of the substrate to be polished in the polishing method according to the present disclosure include those used in the manufacture of a magnetic disk substrate and a magnetic recording medium substrate as described above, and in particular, a magnetic disk substrate for a perpendicular magnetic recording system. The substrate used for the production of is preferable.

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

<1> The following steps (1) to (5) are included, the following steps (1) to (3) are performed by the same polishing machine, and the following step (5) is performed by a polishing machine different from the polishing machine. The total mass of the silica particles used in the steps (1) to (3) is 65.0% by mass relative to the total mass of the alumina particles and the silica particles used in the steps (1) to (3). The method for manufacturing a magnetic disk substrate, which is 90.0% by mass or less.
(1) A polishing liquid composition A containing alumina particles, silica particles, 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 object to be polished Polishing the surface to be polished by moving the substrate;
(2) A step of rinsing the substrate obtained in step (1),
(3) A polishing liquid composition B containing silica particles 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 Moving the substrate to be polished to polish the surface to be polished;
(4) A step of cleaning the substrate obtained in step (3),
(5) A polishing liquid composition C containing silica particles and water is supplied to the surface to be polished of the substrate obtained in step (4), the polishing pad is brought into contact with the surface to be polished, and / or the polishing pad and / or Moving the substrate to be polished to polish the surface to be polished;

<2> The total mass of the silica particles is preferably 88% by mass or less, more preferably 85% by mass or less, with respect to the sum of the total mass of the alumina particles and the silica particles used in the steps (1) to (3). Yes, and / or preferably 70% by mass or more, more preferably 75% by mass or more, or preferably 78% by mass or less, more preferably 75% by mass or less, and / or preferably 68% by mass. % Or more, more preferably 70% by mass or more, The method for producing a magnetic disk substrate according to <1>.
<3> The polishing time in step (1) is preferably 25% or more and 75% or less, and / or preferably 25% or more, more preferably, with respect to the total polishing time in steps (1) to (3). Is at least 30%, more preferably at least 42%, even more preferably at least 45%, and / or preferably at most 75%, more preferably at most 60%, even more preferably at most 55%, <1 > Or <2> The method for producing a magnetic disk substrate according to <2>.
<4> The total polishing time in steps (1) to (3) is preferably 3 minutes or more and 6 minutes or less, and / or preferably 3 minutes or more, more preferably 3.5 minutes or more, and still more preferably. The magnetic force according to any one of <1> to <3>, which is 3.8 minutes or more and / or preferably 6 minutes or less, more preferably 5 minutes or less, and even more preferably 4.3 minutes or less. A manufacturing method of a disk substrate.
<5> The polishing time in step (1) is 25 to 75% of the total polishing time in steps (1) to (3), and the total time in steps (1) to (3) is 3 to 6 minutes. A method for manufacturing a magnetic disk substrate according to any one of <1> to <4>.
<6> The polishing amount per unit area (1 cm ² ) of the substrate to be polished in the step (1) is preferably 0.4 mg or more, more preferably 0.6 mg or more, further preferably 0.8 mg or more, And / or Preferably it is 2.6 mg or less, More preferably, it is 2.1 mg or less, More preferably, it is 1.7 mg or less, The manufacturing method of the magnetic disc board | substrate in any one of <1> to <5>.
<7> The polishing amount per unit area (1 cm ² ) of the substrate to be polished in the step (3) is preferably 0.0004 mg or more, more preferably 0.004 mg or more, further preferably 0.01 mg or more, And / or preferably 0.85 mg or less, more preferably 0.43 mg or less, further preferably 0.26 mg or less, and even more preferably 0.1 mg or less, according to any one of <1> to <6> Manufacturing method of magnetic disk substrate.
<8> The polishing amount per unit area (1 cm ² ) of the substrate to be polished in the step (5) is preferably 0.085 mg or more, more preferably 0.1 mg or more, further preferably 0.13 mg or more, and even more. Preferably it is 0.15 mg or more, and / or preferably 0.85 mg or less, more preferably 0.7 mg or less, still more preferably 0.5 mg or less, even more preferably 0.4 mg or less, <1> To <7>. A method for manufacturing a magnetic disk substrate according to any one of <7>.
<9> The average secondary particle diameter of the alumina particles is preferably 0.10 μm or more, more preferably 0.15 μm or more, still more preferably 0.20 μm or more, even more preferably 0.25 μm or more, and / or Preferably, it is 0.80 μm or less, more preferably 0.75 μm or less, even more preferably 0.70 μm or less, even more preferably 0.60 μm or less, even more preferably 0.50 μm or less, <1> to <8 The method for producing a magnetic disk substrate according to any one of the above.
<10> The content of alumina particles in the polishing liquid composition A is preferably 0.5% by mass or more, more preferably 0.8% by mass or more, still more preferably 1.0% by mass or more, and / or. , Preferably 10% by weight or less, more preferably 5% by weight or less, further preferably 4% by weight or less, even more preferably 2.5% by weight or less, even more preferably 1.5% by weight or less, or Preferably it is 10 mass% or more, More preferably, it is 15 mass% or more, More preferably, it is 20 mass% or more, and / or Preferably it is 80 mass% or less, More preferably, it is 60 mass% or less, More preferably, it is 40 mass% The method for manufacturing a magnetic disk substrate according to any one of <1> to <9>, wherein:
<11> The alumina particles contain α-alumina, and the alpha conversion rate of α-alumina is preferably 50% or more, more preferably 60% or more, still more preferably 63% or more, and / or preferably 99% or less. The method of manufacturing a magnetic disk substrate according to any one of <1> to <10>, more preferably 90% or less, and still more preferably 80% or less.
<12> The alumina particles contain α-alumina, and the average secondary particle diameter of α-alumina is preferably 0.10 μm or more, more preferably 0.15 μm or more, further preferably 0.20 μm or more, and even more preferably. And / or preferably 0.80 μm or less, more preferably 0.75 μm or less, even more preferably 0.70 μm or less, even more preferably 0.60 μm or less, and even more preferably 0.50 μm. The method for manufacturing a magnetic disk substrate according to any one of <1> to <11>, wherein:
<13> The alumina particles contain α-alumina, and the content of α-alumina in the polishing composition A is preferably 0.4% by mass or more, more preferably 0.5% by mass or more, and still more preferably 0.6. % By mass or more, even more preferably 0.7% by mass or more, and / or preferably 10% by mass or less, more preferably 7.5% by mass or less, still more preferably 4% by mass or less, and even more preferably. The method for producing a magnetic disk substrate according to any one of <1> to <13>, which is 2% by mass or less, and more preferably 1% by mass or less.
<14> The alumina particles contain intermediate alumina, and the average secondary particle diameter of the intermediate alumina is preferably 0.01 μm or more, more preferably 0.05 μm or more, further preferably 0.10 μm or more, and even more preferably 0. And / or preferably 0.6 μm or less, more preferably 0.5 μm or less, even more preferably 0.4 μm or less, even more preferably 0.3 μm or less, even more preferably 0.2 μm or less. The method for manufacturing a magnetic disk substrate according to any one of <1> to <13>.
<15> The alumina particles contain intermediate alumina, and the content of intermediate alumina in the polishing composition A is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and still more preferably 0.2%. % By mass or more, even more preferably 0.5% by mass or more, and / or preferably 3% by mass or less, more preferably 1% by mass or less, still more preferably 0.8% by mass or less, even more preferably. The method for producing a magnetic disk substrate according to any one of <1> to <14>, which is 0.6% by mass or less, and more preferably 0.4% by mass or less.
<16> The alumina particles contain α alumina and intermediate alumina, and the mass ratio of α alumina to intermediate alumina (mass% of α alumina / mass% of intermediate alumina) is preferably 90/10 to 10/90. The method for manufacturing a magnetic disk substrate according to any one of <1> to <15>, preferably 85/15 to 40/60, more preferably 80/20 to 70/30.
<17> The average primary particle diameter (D50) of the silica particles is preferably 15 nm or more, more preferably 30 nm or more, further preferably 40 nm or more, and / or preferably 120 nm or less, more preferably 100 nm or less, The method for producing a magnetic disk substrate according to any one of <1> to <16>, preferably 80 nm or less, more preferably 75 nm or less, and even more preferably 60 nm or less.
<18> The mass ratio of alumina particles to silica particles (alumina particle mass / silica particle mass) in the polishing liquid composition A is preferably 80/20 to 10/90, more preferably 60/40 to 15/85, and further The method for manufacturing a magnetic disk substrate according to any one of <1> to <17>, preferably 40/60 to 20/80.
<19> The ratio of the average secondary particle diameter of alumina particles to the average primary particle diameter (D50) of silica particles (alumina particle diameter / silica particle diameter) is preferably 1 or more, more preferably 2 or more, and still more preferably. The magnetic disk according to any one of <1> to <18>, which is 5 or more and / or preferably 100 or less, more preferably 50 or less, still more preferably 10 or less, and even more preferably 7 or less. A method for manufacturing a substrate.
<20> The content of silica particles contained in the polishing composition A is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, further preferably 1.5% by mass or more, and even more preferably. Is 2.5% by weight or more, and / or preferably 20% by weight or less, more preferably 15% by weight or less, still more preferably 10% by weight or less, even more preferably 5% by weight or less, <1 > To <19> The method for producing a magnetic disk substrate according to any one of <19>.
<21> The pH of the polishing composition A is preferably from 1.0 to 6.0, more preferably from 1.0 to 4.0, still more preferably from 1.0 to 3.0, and even more preferably. Is a method for producing a magnetic disk substrate according to any one of <1> to <20>, which has a pH of 1.0 to 2.0.
<22> The average primary particle diameter (D50) of the silica particles used in the polishing liquid composition B is preferably 15 nm or more, more preferably 30 nm or more, still more preferably 40 nm or more, and / or preferably 120 nm or less. The method of manufacturing a magnetic disk substrate according to any one of <1> to <21>, more preferably 100 nm or less, still more preferably 80 nm or less, still more preferably 75 nm or less, and even more preferably 60 nm or less.
<23> The content of silica particles in the entire abrasive contained in the polishing composition B is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and even more preferably. The method for producing a magnetic disk substrate according to any one of <1> to <22>, which is 100% by mass.
<24> The method for producing a magnetic disk substrate according to any one of <1> to <23>, wherein the polishing liquid composition B does not contain alumina abrasive grains.
<25> The average primary particle diameter (D50) of the silica particles used in the polishing liquid composition C is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 15 nm or more, still more preferably 20 nm or more, and / Or Preferably, it is 120 nm or less, More preferably, it is 100 nm or less, More preferably, it is 50 nm or less, More preferably, it is 40 nm or less, The manufacturing method of the magnetic disc substrate in any one of <1> to <24> .
<26> The content of silica particles contained in the polishing composition C is preferably 0.5% by mass or more, more preferably 1% by mass or more, further preferably 3% by mass or more, and even more preferably 4% by mass. <1> to <25>, and / or preferably 20% by mass or less, more preferably 15% by mass or less, further preferably 10% by mass or less, and even more preferably 8% by mass or less. The manufacturing method of the magnetic disc board | substrate in any one.
<27> The cleaning in the step (4) is performed using the cleaning composition, and 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. And / or 13 or less, The method for producing a magnetic disk substrate according to any one of <1> to <26>.
<28> The method for manufacturing a magnetic disk substrate according to any one of <1> to <27>, wherein the substrate to be polished is an aluminum alloy substrate plated with Ni—P.
<29> The following steps (1) to (5) are included, the following steps (1) to (3) are performed by the same polishing machine, and the following step (5) is performed by a polishing machine different from the polishing machine. The total mass of the silica particles used in the steps (1) to (3) is 65.0% by mass relative to the total mass of the alumina particles and the silica particles used in the steps (1) to (3). The method for polishing a magnetic disk substrate, which is 90.0% by mass or less.
(1) A polishing liquid composition A containing alumina particles, silica particles, 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 object to be polished Polishing the surface to be polished by moving the substrate;
(2) A step of rinsing the substrate obtained in step (1),
(3) A polishing liquid composition B containing silica particles 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 Moving the substrate to be polished to polish the surface to be polished;
(4) A step of cleaning the substrate obtained in step (3),
(5) A polishing liquid composition C containing silica particles and water is supplied to the surface to be polished of the substrate obtained in step (4), the polishing pad is brought into contact with the surface to be polished, and / or the polishing pad and / or Moving the substrate to be polished to polish the surface to be polished;

  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 composition A, B, and C was prepared as follows, and the to-be-polished substrate containing process (1)-(5) was grind | polished on 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 compositions A to C
[Preparation of polishing composition A used in step (1)]
A polishing composition A was prepared using alumina abrasive grains A or B shown in Table 1 below, colloidal silica abrasive grains a shown in Table 2 below, citric acid, sulfuric acid, hydrogen peroxide, and water (Table 3 below). The abrasive grains of the polishing composition A and the content thereof were 3 mass% for the alumina abrasive grains A and 1 mass% for the colloidal silica abrasive grains a in Examples 1, 9 and 10. In Examples 2 to 4, 6 and Comparative Example 4, the alumina abrasive grain A was 2 mass%, and the colloidal silica abrasive grain a was 2 mass%. In Examples 5 and 7 and Comparative Example 2, the alumina abrasive grain A was 1% by mass, and the colloidal silica abrasive grain a was 3% by mass. In Example 8, the alumina abrasive grain B was 1 mass%, and the colloidal silica abrasive grain a was 3 mass%. In Comparative Examples 1 and 3, the alumina abrasive grain A was 4% by mass, and no colloidal silica abrasive grain was contained. Further, the content of each other component in the polishing liquid composition A is 0.5% by mass of citric acid, 0.5% by mass of sulfuric acid, and 0.5% by mass of hydrogen peroxide, and the pH of the polishing liquid composition A Was 1.2. In addition, said pH is pH of polishing liquid composition in 25 degreeC, and is a numerical value after 5 minutes, after immersing an electrode using pH meter "HM-30G" (made by Toa Denpa Kogyo Co., Ltd.) ( The same applies below).

[Preparation of polishing composition B used in step (3)]
Polishing liquid composition B was prepared using the colloidal silica abrasive grain a containing the colloidal silica particle shown in the following Table 2, sulfuric acid, hydrogen peroxide, and water (the following Table 3). The content of each component in the polishing composition B was 4% by mass of colloidal silica abrasive grains a, 0.2% by mass of sulfuric acid, and 0.1% by mass of hydrogen peroxide. The pH of the polishing composition B was 1.6.

[Preparation of polishing composition C used in step (5)]
Polishing liquid composition C was prepared using the colloidal silica abrasive grain b containing the colloidal silica particle shown in following Table 2, sulfuric acid, hydrogen peroxide, and water. The content of each component in the polishing liquid composition C is 6% by mass of colloidal silica abrasive grains b, 0.5% by mass of sulfuric acid, and 0.3% by mass of hydrogen peroxide. The pH of the polishing liquid composition C is 1.3. Met.

2. Measurement method of each parameter [Measurement of average secondary particle diameter of alumina particles]
A 0.5% by mass poise 530 (manufactured by Kao Corporation; special polycarboxylic acid type polymer surfactant) aqueous solution is used as a dispersion medium and placed in the following measuring apparatus, and subsequently the transmittance is 75 to 95%. Samples were added and then subjected to ultrasonic waves for 5 minutes, and then the particle size was measured.
Measuring instrument: Laser diffraction / scattering particle size distribution measuring device “LA920” (manufactured by Horiba Ltd.)
Circulation strength: 4
Ultrasonic intensity: 4

[Measurement method of alpha conversion rate of alumina]
20 g of alumina slurry was dried at 105 ° C. for 5 hours, and the resulting dried product was crushed with a mortar to obtain a powder X-ray diffraction sample. Each sample was analyzed by the powder X-ray diffraction method, and the peak areas on the 104th surface were compared. The measurement conditions by the powder X-ray diffraction method were as follows.
Measurement condition;
Apparatus: Powder X-ray analyzer “RINT2500VC” (manufactured by Rigaku Corporation)
X-ray generation voltage: 40 kV
Radiation: Cu-Kα1 line (λ = 0.154050 nm)
Current: 120 mA
Scan Speed: 10 degrees / minute Measurement step: 0.02 degrees / minute pregelatinization rate (%) = alpha area peculiar to alumina / peak area of WA-1000 × 100
The area of each peak was calculated from the obtained powder X-ray diffraction spectrum using the powder X-ray diffraction pattern comprehensive analysis software JADE (MDI) attached to the powder X-ray diffractometer. The calculation process by the software was calculated based on the instruction manual of the software (Jade (Ver. 5) software, instruction manual Manual No. MJ13133E02, manufactured by Rigaku Corporation). WA-1000 is α-alumina (manufactured by Showa Denko KK) having an α conversion rate of 99.9%.

[Measurement of average primary particle diameter of silica particles and standard deviation of primary particle diameter]
Photos of silica particles observed with a transmission electron microscope (TEM) manufactured by JEOL Ltd. (trade name “JEM-2000FX”, 80 kV, 1 to 50,000 times) are taken as image data with a scanner on a personal computer, and analysis software “WinROOF ( Ver.3.6) ”(distributor: Mitani Corporation) is used to calculate the equivalent circle diameter of each silica particle from 1000 to 2000 silica particle data, and this is used as the diameter to calculate spreadsheet software“ EXCEL ”( The standard deviation of the volume-based particle size (sample standard deviation) was obtained by Microsoft). In addition, based on the particle size distribution data of silica particles obtained by converting the particle diameter to the particle volume with the spreadsheet software “EXCEL”, the ratio of particles having a certain particle size in all particles (volume basis%) Was expressed as the cumulative frequency from the small particle size side, and the cumulative volume frequency (%) was obtained. By plotting the cumulative volume frequency against the particle diameter based on the particle diameter and cumulative volume frequency data of the obtained silica particles, a particle diameter versus cumulative volume frequency graph is obtained. In the graph, the particle diameter at which the cumulative volume frequency from the small particle diameter side becomes 50% was defined as the average primary particle diameter (D50) of the silica particles. Further, the particle diameter at which the cumulative volume frequency from the small particle diameter side is 10% is defined as the primary particle diameter (D10) of the silica particles, and the particle diameter at which the cumulative volume frequency from the small particle diameter side is 90% is The primary particle size (D90) was used.

3. Polishing conditions [Substrate to be polished]
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 (a perforated donut shape with a central part diameter of 25 mm).

[Polishing the substrate to be polished]
The substrate to be polished including steps (1) to (5) was polished. The conditions for each step are shown below. In addition, process (1)-(3) was performed with the same grinding machine, and process (5) was performed with the grinding machine separate from the said grinding machine.

[Step (1): First rough polishing]
Polishing machine: Double-side polishing machine (9B-type double-side polishing machine, manufactured by Speed Fam Co., Ltd.)
Polishing pad: Suede type (foam layer: polyurethane elastomer), thickness 1.04mm, average pore diameter 43μm (manufactured by FILWEL)
Plate rotation speed: 45rpm
Polishing load: 9.8 kPa (set value)
Polishing liquid supply amount: 100 mL / min (0.076 mL / (cm ² · min)), 1-4 min polishing amount: 1.0-1.2 mg / cm ²
Number of substrates loaded: 10 (double-side polishing)

[Step (2): Intermediate rinse]
Rinse conditions:
Rinse solution: Ion exchange water Polishing machine and polishing pad: Same as step (1) Surface plate rotation speed: 45 rpm
Polishing load: 9.8 kPa (set value)
Ion exchange water supply rate: 0.33 min at ² L / min (1.52 mL / (cm ² · min))

[Step (3): Second rough polishing]
Polishing machine and polishing pad: Same platen rotation speed as in step (1): 45 rpm
Polishing load: 9.8 kPa (set value)
Polishing liquid supply amount: 100 mL / min (0.076 mL / (cm ² · min)), 0.67 to 2.67 min Polishing amount: 0.02 to 0.04 mg / cm ²
Step (3) includes a rinsing step under the following conditions after polishing under the above conditions.
Rinse conditions:
Plate rotation speed: 20 rpm
Polishing load: 1.4 kPa (set value)
Ion exchange water supply rate: 15 seconds at 2 L / min

[Step (4): Washing]
The substrate obtained in the step (3) was washed under the following conditions.
1. The substrate obtained in step (3) 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 (5): 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 steps (1) to (3): Suede type (foamed layer: polyurethane elastomer) , Thickness 1.0mm, average pore diameter 5μm (FILWEL)
Plate rotation speed: 40 rpm
Polishing load: 9.8 kPa (set value)
Polishing liquid supply amount: 100 mL / min (0.076 mL / (cm ² · min)), 4 min polishing amount: 0.2 to 0.3 mg / cm ²
Number of substrates loaded: 10 (double-side polishing)
After the step (5), rinsing and washing were performed. The rinsing was performed under the same conditions as in the step (3), and the cleaning was performed under the same conditions as in the step (4).

4). Evaluation method [Evaluation method of alumina stick after cleaning step (4)]
[Method for evaluating residual alumina after cleaning step (4)]
Measuring instrument: S-4800 (manufactured by Hitachi)
Image analysis software: WinROOF Ver. 3.6 (Mitani Corporation)
Evaluation: One substrate was randomly selected from the substrates obtained in the cleaning step (4), and the substrates were observed at 50000 times, 20000 times and 5000 times. Four monochrome photographs were taken at random for each substrate, and twelve monochrome photographs were taken for each magnification. Each image was subjected to 255-level binarization processing with image analysis software, and the upper limit of binary (white side) was set to 255. The lower limit (black side) was 150, the area counted there was residual alumina, and the abundance was calculated. As a result, the total average value is shown in Table 3 below as a relative value with Comparative Example 3 taken as 100. The rinse conditions were the same as those in the step (3), and the cleaning conditions were the same as those in the step (4).

[Calculation method of ratio of silica particles used in steps (1) to (3)]
The “ratio of silica particles used” is a value obtained by dividing the total mass of the silica particles of the polishing liquid compositions A and B supplied to the polishing machine by the sum of the total mass of the alumina particles and the silica particles. The following formula was used.
A = (alumina concentration (%) of polishing liquid composition A) × polishing time (minutes) in step (1))
S = (silica concentration (%) of polishing liquid composition A) × polishing time (minute) of step (1)) + (silica concentration (%) of polishing liquid composition B) × polishing time of step (1) ( Min))
Ratio of silica particles used (%) = (S / (A + S)) × 100

  As shown in Table 3, Examples 1 to 3 and Example 5 containing colloidal silica in the polishing liquid composition A were reduced in the total polishing time as compared with Comparative Example 3 containing no colloidal silica. 4) The amount of residual alumina after (after completion of rough polishing) and the amount of protrusion defects after step (5) (after completion of finish polishing) were reduced. Moreover, from the comparison between Example 4 and Examples 6 to 8 and Comparative Example 3, by including colloidal silica in the polishing liquid composition A, after step (4) in the same time as Comparative Example 3 ( It was possible to reduce the amount of residual alumina after completion of rough polishing and the amount of protrusion defects after step (5) (after completion of finish polishing). Furthermore, from the comparison between Example 9 and Example 10 and Comparative Example 3, by containing colloidal silica in the polishing liquid composition A, the total amount of colloidal silica used in the polishing step is reduced, and the total polishing time is reduced. I let you.

  Also, in actual production, if there are many protrusion defects after final polishing, it cannot be used as a magnetic disk substrate and is therefore re-polished or discarded. The reduction effect can be expected to improve the substrate yield.

Claims (6)

The following steps (1) to (5) are included, the following steps (1) to (3) are performed with the same polishing machine, and the following step (5) is performed with a polishing machine different from the polishing machine, The total mass of the silica particles used in (1) to (3) is 65.0% by mass or more, 90% with respect to the sum of the total mass of the alumina particles and silica particles used in steps (1) to (3). A method for manufacturing a magnetic disk substrate, which is 0.0 mass% or less.
(1) A polishing liquid composition A containing alumina particles, silica particles, 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 object to be polished Polishing the surface to be polished by moving the substrate;
(2) A step of rinsing the substrate obtained in step (1),
(3) A polishing liquid composition B containing silica particles 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 Moving the substrate to be polished to polish the surface to be polished;
(4) A step of cleaning the substrate obtained in step (3),
(5) A polishing liquid composition C containing silica particles and water is supplied to the surface to be polished of the substrate obtained in step (4), the polishing pad is brought into contact with the surface to be polished, and / or the polishing pad and / or Moving the substrate to be polished to polish the surface to be polished;   The magnetic content according to claim 1, wherein the content (mass%) of alumina particles in the polishing liquid composition A is 80% or less with respect to the total content (mass%) of alumina particles and silica particles in the polishing liquid composition A. A manufacturing method of a disk substrate. The polishing time of the step (1) is 25 to 75% with respect to the total polishing time of the steps (1) to (3), and the total time of the steps (1) to (3) is 3 to 6 minutes. A method of manufacturing a magnetic disk substrate according to claim 1 or 2. The method for producing a magnetic disk substrate according to claim 1, wherein the polishing liquid composition B does not contain alumina abrasive grains.   The method of manufacturing a magnetic disk substrate according to claim 1, wherein the substrate to be polished is a Ni—P plated aluminum alloy substrate. The following steps (1) to (5) are included, the following steps (1) to (3) are performed with the same polishing machine, and the following step (5) is performed with a polishing machine different from the polishing machine, The total mass of the silica particles used in (1) to (3) is 65.0% by mass or more, 90% with respect to the sum of the total mass of the alumina particles and silica particles used in steps (1) to (3). A polishing method for a magnetic disk substrate, which is 0.0 mass% or less.
(1) A polishing liquid composition A containing alumina particles, silica particles, 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 object to be polished Polishing the surface to be polished by moving the substrate;
(2) A step of rinsing the substrate obtained in step (1),
(3) A polishing liquid composition B containing silica particles 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 Moving the substrate to be polished to polish the surface to be polished;
(4) A step of cleaning the substrate obtained in step (3),
(5) A polishing liquid composition C containing silica particles and water is supplied to the surface to be polished of the substrate obtained in step (4), the polishing pad is brought into contact with the surface to be polished, and / or the polishing pad and / or Moving the substrate to be polished to polish the surface to be polished;