JP2009187657A - Method of manufacturing substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a substrate which reduces fine waviness of a product to be polished after polishing, for finish polishing of a memory hard disk and polishing of a semiconductor element, to provide a polishing method and to provide a method for reducing the fine waviness. <P>SOLUTION: The method of manufacturing a substrate for a memory hard disk is provided, which uses a suede-like polishing pad having: a polishing liquid composition containing an abrasive and water; at least a base layer and a foaming surface layer; and a surface member made of a polyurethane having 1 to 25 μm average pore diameter and ≤60 μm maximum value of the pore diameter. The abrasive includes an abrasive (a first component) having particle diameter distribution expressed by expression (16): σ>0.9067×r+0.588 and other abrasive (a second component) having an average particle diameter and/or a standard deviation different from those of the first component by 10% or more. In expression (16), r denotes a number based average particle diameter (nm) and σ denotes a number based standard deviation (nm). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a substrate using a polishing composition and a polishing pad, a polishing method, and a method for reducing microwaviness.

  Memory hard disk drives in recent years are required to have a high capacity and a small diameter, and in order to increase the recording density, the flying height of the magnetic head is reduced or the unit recording area is reduced. Along with this, the surface quality required after polishing in the manufacturing process of magnetic disk substrates has become stricter year by year, and the surface roughness, micro-waviness, roll-off, and protrusions are reduced in response to the low flying height of the head. In addition, the size and depth of scratches and pits allowed in response to the decrease in unit recording area are becoming smaller.

In order to meet such demands, an aluminum disk substrate polishing composition comprising colloidal silica particles having different monomodal number particle size distributions, which can provide an aluminum disk substrate with small average waviness and few surface defects. A thing is known (for example, refer patent document 1).
Further, a polishing composition containing colloidal silica having a specific particle size distribution that is excellent in surface smoothness and capable of polishing at an economical speed without generating surface defects is known. (For example, refer to Patent Document 2).

  However, as the recording density increases year by year, it is necessary to reduce the flying height of the head, so that the specifications of the micro waviness required for the substrate are becoming stricter. Therefore, the quality cannot be achieved by the combination of the conventional polishing composition and the polishing pad described in Patent Documents 1 and 2 above.

  Further, Patent Document 3 discloses a method for reducing microwaviness by using a pad having no pores on the surface of the polishing pad. However, in this method, since the polishing liquid is not sufficiently held by the polishing pad, the polishing rate is increased. There was a problem of being slow.

JP 2002-30274 A JP 2001-323254 A JP 2001-62704 A

  An object of the present invention is to provide a substrate manufacturing method, a polishing method, and a micro-waviness reduction method that can reduce micro-waviness of an object to be polished after polishing for polishing a memory hard disk or polishing a semiconductor element. .

That is, the gist of the present invention is as follows.
[1] A suede type comprising a polishing composition comprising an abrasive and water, at least a base layer and a foamed surface layer, having an average pore diameter of 1 to 25 μm and a maximum pore diameter A method of manufacturing a memory hard disk substrate using a polishing pad having a polyurethane surface member of 60 μm or less, wherein the abrasive is represented by the formula (16):
σ> 0.9067 × r + 0.588 (16)
(Wherein r represents the number-based average particle diameter (nm), and σ represents the number-based standard deviation (nm))
For a memory hard disk, comprising an abrasive having a particle size distribution represented by the formula (first component) and the first component and another abrasive (second component) having an average particle size and / or standard deviation different by 10% or more. Substrate manufacturing method,
[2] The content of particles having a particle size of 5 to 120 nm in the total amount of the abrasive is 50% by volume or more, and small particles having a particle size of 5 nm to less than 40 nm are used as the abrasive. 10 to 100% by volume based on the total amount, 0 to 70% by volume of medium-sized particles having a particle size of 40 nm to less than 80 nm with respect to the total amount of particles having a particle size of 5 to 120 nm, and a particle size of 80 to 120 nm The method for producing a substrate according to the above [1], wherein the large particle size is 0 to 40% by volume with respect to the total amount of the particles having a particle size of 5 to 120 nm,
[3] The method for producing a substrate according to [1] or [2], wherein the abrasive is silica.
[4] The method for producing a substrate according to any one of [1] to [3], wherein the polishing composition further contains an oxidizing agent,
[5] The method for producing a substrate according to the above [4], wherein the content of the oxidizing agent is 0.01 to 5% by weight in the polishing composition.
[6] The method for producing a substrate according to any one of [1] to [3], wherein the polishing composition further contains an acid and / or a salt thereof,
[7] The method for producing a substrate according to [6], wherein the acid contains an inorganic acid and / or an organic phosphonic acid,
[8] The method for producing a substrate according to [6] or [7], wherein the content of the acid and the salt thereof is 0.0025 to 1% by weight in the polishing composition.
[9] The method for producing a substrate according to any one of [1] to [8], wherein the content of the abrasive is 1 to 15% by weight in the polishing composition.
[10] The method for producing a substrate according to any one of [1] to [9], wherein the flow rate of the polishing composition is 40 to 130 cc / min,
[11] The method for producing a substrate according to any one of [1] to [10], wherein the substrate is a Ni-P plated aluminum alloy substrate,
[12] A suede type comprising a polishing composition comprising an abrasive and water, at least a base layer and a foamed surface layer, having an average pore diameter of 1 to 25 μm and a maximum pore diameter A method for polishing a substrate for a memory hard disk using a polishing pad having a polyurethane surface member of 60 μm or less, wherein the abrasive is represented by the formula (16):
σ> 0.9067 × r + 0.588 (16)
(Wherein r represents the number-based average particle diameter (nm), and σ represents the number-based standard deviation (nm))
For a memory hard disk, comprising an abrasive having a particle size distribution represented by the formula (first component) and the first component and another abrasive (second component) having an average particle size and / or standard deviation different by 10% or more. Substrate polishing method,
[13] A suede type comprising a polishing composition comprising an abrasive and water, at least a base layer and a foamed surface layer, having an average pore diameter of 1 to 25 μm and a maximum pore diameter A method for reducing microwaviness of a memory hard disk substrate using a polishing pad having a polyurethane surface member of 60 μm or less, wherein the abrasive is represented by the formula (16):
σ> 0.9067 × r + 0.588 (16)
(Wherein r represents the number-based average particle diameter (nm), and σ represents the number-based standard deviation (nm))
For a memory hard disk, comprising an abrasive having a particle size distribution represented by the formula (first component) and the first component and another abrasive (second component) having an average particle size and / or standard deviation different by 10% or more. The present invention relates to a method for reducing minute waviness of a substrate.

  According to the substrate manufacturing method of the present invention, it is possible to manufacture a memory hard disk or a semiconductor element in which the fine waviness of the polished object after polishing is significantly reduced.

FIG. 1 is a graph of the particle size of the abrasive particles used in each example versus the cumulative volume frequency. FIG. 2 is a schematic view showing a portion on a substrate scanned with a differential interference microscope when measuring micropits.

  The method for producing a substrate of the present invention is characterized by using a polishing liquid composition containing water and an abrasive and a polishing pad having a surface member having an average pore diameter of 0.01 to 35 μm. In the present invention, By using such a polishing liquid composition and a polishing pad, the effect of significantly reducing the fine waviness of the substrate after polishing is exhibited.

Among them, in the present invention, by using the polishing pad having the specific surface member as described above, the polishing composition can be appropriately held in the polishing pad, so that while maintaining a high polishing rate, The effect of reducing the fine waviness of the object to be polished and producing a high-quality memory hard disk or semiconductor element is exhibited.
A conventionally used polishing pad has relatively large pores (average pore diameter of about 40 to 80 μm) on the pad surface, and when such a polishing pad is used, the effect of reducing microwaviness is sufficient. It wasn't.

  As used herein, microwaviness refers to irregularities on the surface having an intermediate wavelength between roughness and waviness, and is classified into short wavelength waviness (wavelength of 50 to 500 μm) and long wavelength waviness (wavelength of 500 μm to 5 mm). The

  That is, the minute waviness becomes an index indicating the smoothness of the surface of the object and affects the flying height of the magnetic head. Therefore, the smaller the value of the microwaviness, the better the smoothness of the surface of the object, and the magnetic head can be lowered.

In general, the minute waviness on the surface of the object is obtained as an average of each portion extracted at random from the surface of the object. On the surface of the object, the minute undulations at the individual positions are not uniform and usually show considerable variations. Therefore, in order to obtain the minute waviness on the surface of the object, it is necessary to determine the measurement position and the number of the measurement positions so that the population average can be estimated effectively. Therefore, the reliability of data greatly depends on the selection of the measurement position and the number thereof.
The details of the method for measuring microwaviness in the present invention will be described in the examples described later.

  The structure of the polishing pad used in the present invention is not particularly limited as long as it has a surface member having an average pore diameter of 0.01 to 35 μm. For example, “CMP Technology Basic Example Course Series 2nd Mechano” Suede as described in Chemical Polishing (CMP) Basics and Examples (Polishing Pad Edition), May 27, 1998, Global Net Co., Ltd., “CMP Science, Masahiro Kashiwa, Science Forum, Chapter 4” There are types, nonwoven fabric types, polyurethane closed-cell foam types, and two-layer structure types in which these are laminated. From the viewpoint of reducing surface roughness, microwaviness, micro scratches that are surface defects, and wide scratches, suede types are preferred. Here, the suede type refers to a polishing pad having a structure having at least a base layer and a foamed surface layer. As the material of the base layer, a high-hardness resin such as polyethylene terephthalate (PET) is preferable. The material for the surface layer is preferably polyurethane. Examples of the suede type polishing pad are not particularly limited, and examples thereof include those described in JP-A Nos. 11-335979 and 2001-62704.

  The average pore diameter of the surface member of the polishing pad is 35 μm or less, preferably 30 μm or less, more preferably 27 μm or less, and even more preferably 25 μm or less, from the viewpoint of reducing scratches and / or microwaviness. From the viewpoint of holding the polishing liquid of the pad, the average pore diameter is 0.01 μm or more, preferably 0.1 μm or more, more preferably 0 in order to keep the polishing liquid in the pores and prevent the liquid from running out. 0.5 μm or more, more preferably 1 μm or more. Further, the maximum value of the pore size of the polishing pad is preferably 100 μm or less, more preferably 70 μm or less, still more preferably 60 μm or less, and particularly preferably 50 μm or less, from the viewpoint of reducing scratches and / or microwaviness.

  Moreover, the polishing composition used in the present invention is a polishing composition containing an abrasive and water, and the abrasive can be an abrasive generally used for polishing. . Examples of the abrasive include metal; metal or metalloid carbide, nitride, oxide, boride; diamond and the like. The metal or metalloid element is derived from the 2A, 2B, 3A, 3B, 4A, 4B, 5A, 6A, 7A or 8A group of the periodic table (long period type). Specific examples of the abrasive include aluminum oxide, silicon carbide, diamond, magnesium oxide, zinc oxide, titanium oxide, cerium oxide, zirconium oxide, and silica. The use of one or more of these improves the polishing rate. It is preferable from the viewpoint. Among these, aluminum oxide, silica, cerium oxide, zirconium oxide, titanium oxide, and the like are suitable for polishing a substrate for precision parts such as a semiconductor wafer, a semiconductor element, and a magnetic recording medium substrate. As for aluminum oxide, various crystal systems such as α, θ, and γ are known, but can be appropriately selected and used according to the application. Of these, silica, particularly colloidal silica, is suitable for final finishing polishing for high recording density memory magnetic disk substrates that require higher smoothness and for polishing semiconductor device substrates.

  In the present invention, it is more preferable to use silica as an abrasive from the viewpoint of reducing surface roughness (Ra, Rmax), microwaviness, reducing surface defects such as scratches, and improving surface quality. . Examples of the silica include colloidal silica, fumed silica, surface-modified silica, and the like. Among these, colloidal silica is preferable. In addition, colloidal silica can be obtained by the manufacturing method produced | generated from silicic acid aqueous solution, for example.

  From the viewpoint of surface roughness (Ra, Rmax) and micro waviness reduction, micropit reduction, and scratch reduction, the content of particles having a particle diameter of 5 nm to 120 nm in the total amount of the abrasive is 50% by volume or more. 10 to 100% by volume of small particle size particles having a particle size of 5 nm to less than 40 nm with respect to the total amount of particles having a particle size of 5 to 120 nm, and medium particle size particles having a particle size of less than 40 nm to 80 nm. It is preferable to contain 0 to 70% by volume with respect to the total amount of particles, and 0 to 40% by volume of large particle size particles having a particle size of 80 to 120 nm with respect to the total particle size of 5 to 120 nm. .

  Further, from the viewpoint of reducing the micropits, the content of particles of 5 to 120 nm in the total amount of the abrasive is 50% by volume or more, and small particles having a particle diameter of 5 nm to less than 40 nm are used as the abrasive. 10 to 70% by volume with respect to the total amount of 120 nm particles, 20 to 70% by volume of medium-sized particles having a particle size of less than 40 to 80 nm with respect to the total amount of 5 to 120 nm particles, and a particle size of It is preferable to contain 0.1 to 40% by volume of large particle diameters of 80 nm to 120 nm with respect to the total amount of particles having a particle diameter of 5 to 120 nm.

  Here, the micropits are (1) a dent that can be observed only when the substrate surface is sufficiently flat, and (2) an atomic force when observed with a differential interference optical microscope. When observing with a microscope, it is an inverted conical dent having a diameter of 0.2 to 5 μm and a depth of 10 to 100 nm, and (3) means that an Al element is detected at the bottom of the dent. The detection of Al element can be confirmed by combining a scanning electron microscope (SEM) and an elemental analysis method (EDS, Auger spectroscopy).

  As the average particle size of the abrasive becomes smaller, this micropit has insufficient mechanical grinding force. For example, it is difficult to discharge residues such as stabs of alumina abrasive grains in the previous process, and those discharged in the late stage of polishing. It is considered that micropits are generated by remaining as a dent without being ground.

  The abrasive used in the present invention preferably contains 50% by volume or more of particles having a particle diameter of 5 to 120 nm. The content of the particles having a particle diameter of 5 to 120 nm is preferably 55% by volume or more, and more preferably 60% by volume or more, from the viewpoint of reducing micropits, surface roughness, and scratches.

  From the viewpoint of reducing micropits, the content of the small particle size is preferably 12 to 68% by volume, more preferably 15 to 65% by volume, still more preferably 20 to 60% by volume, and most preferably 30 to 60%. The content of the volume% and medium particle diameter is preferably 25 to 70 volume%, more preferably 25 to 60 volume%, still more preferably 30 to 50 volume%, and the content of the large particle diameter is 0. 5 to 35% by volume is preferable, and 1 to 30% by volume is more preferable.

  Among them, the abrasive used in the present invention is 5 to 70% by volume, preferably 10 to 50%, of particles having a particle size of 10 to 30 nm with respect to the total amount of particles having a particle size of 5 to 120 nm from the viewpoint of reducing micropits. Volume%, particles having a particle diameter of 45 nm to 75 nm are 20 to 70 volume%, preferably 22 to 65 volume%, and particles having a particle diameter of 90 nm to 110 nm are 0.1 to 25 volume%, preferably 1 to 15 volumes. % Content is desirable.

  The particle size distribution of the abrasive can be determined by the following method. That is, a photograph obtained by observing the abrasive particles with a transmission electron microscope (TEM) “JEM-2000FX” (80 kV, 1 to 50,000 times) manufactured by JEOL is taken into a personal computer (PC) with a scanner, and analysis software “WinROOF” ( After obtaining the equivalent circle diameter of each particle using a distributor (Mitani Corporation), analyzing the data of more than 1000 particles, spreadsheet software “EXCEL” ( Converted from particle diameter to particle volume by Microsoft). First, the ratio (volume basis%) of particles of 5 nm to 120 nm (5 to 120 nm) in all particles is calculated, and further 5 nm to 40 nm (5 nm to less than 40 nm) in the entire set of particles of 5 nm to 120 nm. The ratio (volume basis%) of three regions of 40 nm or more and less than 80 nm (40 nm to less than 80 nm) and 80 nm or more and 120 nm or less (80 nm to 120 nm) is determined. Similarly, the ratio (volume reference%) of three regions of 10 nm to 30 nm, 45 nm to 75 nm, and 90 nm to 110 nm is also obtained.

In the present invention, the abrasive preferably has a number-based standard deviation value (σ) satisfying the formula (1) with respect to the number-based average particle diameter (r) from the viewpoint of the polishing rate. It is more preferable to satisfy (2), and it is still more preferable to satisfy Formula (3).
σ ≧ 0.3 × r (1)
σ ≧ 0.34 × r (2)
σ ≧ 0.375 × r (3)
(Wherein r represents the number-based average particle diameter (nm), and σ represents the number-based standard deviation (nm))

Moreover, it is preferable to satisfy | fill Formula (4) from a viewpoint of surface roughness, and it is still more preferable to satisfy | fill Formula (5).
−0.2 × r + 25 ≧ σ (4)
−0.25 × r + 25 ≧ σ (5)
(Wherein r and σ are the same as above)

  The average particle diameter (r) of the abrasive and the standard deviation (δ) based on the number are calculated by calculating the equivalent circle diameter of 1000 or more abrasive particles obtained when measuring the particle size distribution. By processing with “EXCEL” (manufactured by Microsoft Corporation), the number-based average particle diameter (r) and standard deviation value (σ) can be obtained.

  In addition, based on the particle size distribution data of the abrasive particles obtained by converting the particle diameter to the particle volume with the spreadsheet software “EXCEL”, the ratio of particles having a certain particle diameter in all particles (volume basis%) ) Is expressed as a cumulative frequency from the small particle diameter side to obtain a cumulative volume frequency (%). By plotting the cumulative volume frequency against the particle diameter based on the particle diameter and cumulative volume frequency data of the abrasive particles obtained as described above, a particle diameter versus cumulative volume frequency graph is obtained.

In the present invention, the abrasive has the following formulas (6) and (7) in which the cumulative volume frequency (V) in the particle diameter range of 60 to 120 nm is the particle diameter (R) in the particle diameter versus cumulative volume frequency graph. :
V ≧ 0.5 × R (6)
V ≦ 0.25 × R + 75 (7)
(In the formula, R represents the particle diameter (nm) of the abrasive, and V represents the cumulative volume frequency (%) from the small particle diameter side of the abrasive)
Preferably from a viewpoint of improving the smoothness of the surface of the substrate by reducing micro waviness on the surface of the disk substrate, the cumulative volume frequency is 90% in the range of the particle diameter of 105 nm or more. What has a particle size distribution is still more preferable.

In the present invention, the formula (1) is an index indicating the spread of the particle size distribution of the abrasive particles, and the abrasive particles having a particle size distribution within such a range have a certain size or more spread. It means that it has.
In the present invention, the formulas (6) and (7) are indexes indicating the abundance ratio of abrasive particles, and the abrasives satisfying the formulas (6) and (7) in a particle diameter range of 60 to 120 nm. It means that the particles contain particles having a predetermined particle diameter at a certain ratio or more.
By using an abrasive that satisfies these formulas (1) to (7), the fine waviness can be reduced to a practically sufficient level without impairing productivity.

  The abrasive used in the present invention has a different particle size distribution even if it is composed of one type of abrasive having a specific particle size distribution as long as it has the particle size distribution as described above. It may be formed by mixing two or more kinds of abrasives. In addition, when using 2 or more types of abrasives, the particle size distribution of an abrasive means the particle size distribution of the mixed abrasives.

In addition, as the abrasive, from the viewpoint of improving the smoothness of the surface of the substrate by reducing the surface roughness (TMS-Ra) of the substrate, the particle size is 40 to 100 nm in the particle size versus cumulative volume frequency graph. For the cumulative volume frequency (V) in the range of
V ≧ 0.5 × R + 40 (8)
Preferably having a particle size distribution that satisfies the following formula (9):
V ≧ 1 × R + 20 (9)
More preferably, it has a particle size distribution that satisfies the following formula. In the particle size range of 40 to 60 nm, V is R, and the following formula (10):
V ≧ 1.5 × R (10)
More preferably, it has a particle size distribution satisfying the following formula. In the particle size range of 40 to 50 nm, V is R and R is the following formula (11):
V ≧ 3 × R-60 (11)
Particularly preferred are those having a particle size distribution that satisfies the following formula (12):
V ≧ R + 50 (12)
Those having a particle size distribution satisfying the above are most preferable. Further, from the viewpoint of the polishing rate, in the range of 1 to 3 nm in the particle diameter, V is R with respect to R (Equation 13):
V ≦ 8R + 5 (13)
What has the particle size distribution which satisfy | fills is preferable.

  In the present specification, “surface roughness (TMS-Ra)” is measured by a light scattering surface roughness measuring machine: TMS-2000RC (manufactured by Schmitt Measurement Systems, Inc.). The surface roughness [Ra (Å)] of the measurement object to be measured (hereinafter referred to as the object).

In addition, as an abrasive, from the viewpoint of carrier noise, in the particle size vs. cumulative volume frequency graph, (a) the cumulative volume frequency (V) in the range of 5 to 40 nm in the particle size (R) Formula (14):
V ≦ 2 × (R-5) (14)
And (b) the cumulative volume frequency (V) in the particle size range of 20 to 40 nm is the above formula (15) for the particle size (R):
V ≧ 0.5 × (R-20) (15)
It is preferable to have a particle size distribution that satisfies Since the particle size distribution of the particles used as the abrasive satisfies the above (a), the occurrence of carrier squeal in the polishing process of the disk substrate can be suppressed. On the other hand, since the particle size distribution of the particles satisfies the above (b), micropits are effectively reduced and a high polishing rate can be obtained.

  When polishing a disk substrate using a polishing machine, the substrate is loaded in an eccentric state in a holder (carrier) set between the polishing disks. As the polishing progresses, carrier noise may occur from around the carrier. Carrier squeal generally occurs when a polishing composition containing a large number of abrasive particles having a particle size of 40 nm or less is used, and when the carrier squeal is mild, it is intermittently or continuously called squeezing. Although the sound is only generated, if it is severe, the entire polishing machine may start to vibrate and the polishing process may have to be interrupted.

In the present invention, the abrasive is an abrasive having a particle size distribution represented by formula (16) (first component) and other abrasives having an average particle size and / or standard deviation different from the first component. It is preferably used as a mixture with (second component).
σ> 0.9067 × r ^{+ 0.588} (16)
(Wherein r represents the number-based average particle diameter (nm), and σ represents the number-based standard deviation (nm))

Here, the equation (16) shows the state of the particle size distribution of the abrasive, and the abrasive having the particle size distribution satisfying the equation (16) has a relatively wide distribution width according to the average particle size. Indicates a wide state (so-called broad state). The standard deviation is preferably 30 or less from the viewpoint of surface roughness and scratch reduction,
σ> 0.71 × r ^{+ 0.7}
It is more preferable to satisfy the particle size distribution represented by
σ> 0.57 × r ^{+ 0.8}
More preferably, the particle size distribution represented by

  The abrasive of the second component may be an abrasive that differs from the abrasive of the first component in at least one of the average particle diameter or the standard deviation. Above all, from the viewpoint of improving the polishing rate and reducing the surface roughness and microwaviness, the second component abrasive may differ by 10% or more in average particle size or standard deviation from that of the first component abrasive. Preferably, it is more preferably different by 20% or more.

The particle size distribution of the abrasive of the second component may have the particle size distribution represented by the formula (16). From the viewpoints of improving the polishing rate and reducing the surface roughness and microwaviness. Therefore, it is preferable to have a particle size distribution represented by Formula (17).
σ ≦ 0.9067 × r ^{+ 0.588} (17)

  Here, the abrasive having a particle size distribution satisfying the equation (17) is in a particle size distribution state other than the equation (16), that is, a state in which the particle size distribution is relatively narrow according to the average particle size ( So-called sharp state). The standard deviation is preferably 1 or more from the viewpoint of improving the polishing rate.

  Further, a third component abrasive may be contained. The abrasive of the third component may be in the broad state or in a sharp state, and a broad state of the abrasive and a sharp state of the abrasive may be used in combination.

  As a quantitative ratio (first component / second component, weight ratio) between the first component abrasive and the second component abrasive in the polishing composition, the polishing rate is improved, and the surface roughness and micro-waviness are reduced. In view of the above, 1: 0.05 to 0.05: 1 is preferable, 1: 0.1 to 0.1: 1 is more preferable, 1: 0.2 to 0.2: 1 is further preferable, and 1: 0.25 to 0.25: 1 is particularly preferred.

  The content of the abrasive in the polishing composition is preferably 0.5% by weight or more, more preferably 1% by weight or more, further preferably 3% by weight or more, and particularly preferably 5% from the viewpoint of improving the polishing rate. From the viewpoint of improving the surface quality and economy, it is preferably 20% by weight or less, more preferably 15% by weight or less, still more preferably 13% by weight or less, and particularly preferably 10% by weight. % Or less. That is, the content is preferably 0.5 to 20% by weight, more preferably 1 to 15% by weight, still more preferably 3 to 13% by weight, and particularly preferably 5 to 10% by weight.

  In addition, the polishing composition used in the present invention may further contain an oxidizing agent from the viewpoint of improving the polishing rate, reducing the surface roughness (Ra, Rmax) and microwaviness. As the oxidizing agent, an oxidizing agent described in Kyoritsu Shuppan "Chemical Dictionary 3" P910 can be used. Among these, hydrogen peroxide, iron (III) nitrate, peracetic acid, ammonium peroxodisulfate, iron (III) sulfate, and iron (III) ammonium sulfate are preferable. Hydrogen peroxide is particularly preferable from the viewpoint that metal ions do not adhere to the surface and are generally used and inexpensive. These oxidizing agents may be used alone or in admixture of two or more.

  From the viewpoint of improving the polishing rate, the content of the oxidizing agent in the polishing composition is preferably 0.002% by weight or more, more preferably 0.005% by weight or more, still more preferably 0.007% by weight or more, Particularly preferably, it is 0.01% by weight or more, and preferably 20% by weight from the viewpoint of reducing surface roughness and micro-waviness, reducing surface defects such as pits and scratches and improving surface quality, and economical efficiency. Hereinafter, it is more preferably 15% by weight or less, further preferably 10% by weight or less, and particularly preferably 5% by weight or less. The content is preferably 0.002 to 20% by weight, more preferably 0.005 to 15% by weight, still more preferably 0.007 to 10% by weight, and particularly preferably 0.01 to 5% by weight. .

  In addition, the polishing composition may contain an acid and / or a salt thereof from the viewpoint of improving the polishing rate, reducing the surface roughness (Ra, Rmax) and microwaviness, and reducing surface defects such as scratches. Good. As the acid and / or salt thereof, a compound having a pK1 of 2 or less is preferable. From the viewpoint of reducing fine scratches, pK1 is 1.5 or less, more preferably 1 or less, and most preferably not represented by pK1. A compound exhibiting strong acidity is desirable. Examples thereof include acids described in the revised 4th edition, Chemical Handbook (Basic) II, pp316-325 (Edited by Chemical Society of Japan). Among them, inorganic acids and organic phosphonic acids are used from the viewpoint of reducing wide scratches. preferable. Among inorganic acids, nitric acid, sulfuric acid, hydrochloric acid, and perchloric acid are more preferable. Among organic phosphonic acids, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), and diethylenetriaminepenta (methylenephosphonic acid) are more preferable.

  The salt is not particularly limited, and specific examples include salts with metals, ammonium, alkylammonium, organic amines 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 reducing fine scratches. These acids and salts thereof may be used alone or in admixture of two or more.

  The content of the acid and its salt in the polishing composition is preferably 0.0001 to 5% by weight, more preferably 0.0003 to 5% from the viewpoint of exhibiting a sufficient polishing rate and improving the surface quality. It is 3% by weight, more preferably 0.001 to 2% by weight, and particularly preferably 0.0025 to 1% by weight.

  The water in the polishing composition is used as a medium, and for example, distilled water, ion exchange water, ultrapure water, or the like is used. The content thereof is preferably 55 to 99.4799% by weight, more preferably 67 to 98.9947% by weight, still more preferably 75 to 96.992% by weight, particularly preferably from the viewpoint of efficiently polishing an object to be polished. Is 84-94.9875 wt%.

  The concentration of each component such as abrasive, water, oxidant, acid and / or salt thereof in the polishing composition may be any of the concentration during production of the composition and the concentration during use. . Usually, a polishing composition is produced as a concentrated liquid, and it is often used after being diluted at the time of use.

  Moreover, other components can be mix | blended with the polishing liquid composition of this invention as needed. Examples of the other components include a thickener, a dispersant, a rust inhibitor, a basic substance, and a surfactant.

  The polishing composition of the present invention can be prepared by mixing the polishing material, oxidizing agent, acid and / or salt thereof, water, and other components as required, by a known method.

  Examples of the method for producing a substrate of the present invention include a method using the polishing composition when the substrate to be polished is polished using the polishing pad. As a polishing method for a substrate to be polished, a polishing liquid composition is prepared by using the polishing liquid composition or by mixing each component so as to be the composition of the polishing liquid composition. A polishing pad is supplied to polish the substrate to be polished. In particular, a substrate for precision parts such as a memory hard disk substrate can be suitably manufactured. In addition, this method can remarkably reduce the fine waviness and exhibit a high polishing rate. Therefore, the present invention relates to a method for polishing a substrate and a method for reducing micro waviness of a substrate.

  The conditions of the substrate production method are not particularly limited. For example, the flow rate of the polishing composition is preferably 20 to 200 cc / min, preferably 30 to 150 cc / min per substrate from the viewpoint of reducing scratches. More preferred is 40 to 130 cc / min.

  Examples of the material of the substrate targeted by the polishing composition of the present invention include metals, metalloids such as silicon, aluminum, nickel, tungsten, copper, tantalum, and titanium, and alloys thereof, and glass, glassy carbon, and amorphous. Examples thereof include glassy substances such as carbon, ceramic materials such as alumina, silicon dioxide, silicon nitride, tantalum nitride, and titanium carbide, and resins such as polyimide resins. Among these, metals such as aluminum, nickel, tungsten, and copper and alloys containing these metals as the main component are substrates, or a substrate containing them, such as a semiconductor substrate such as a semiconductor element. For example, a Ni-P plated aluminum alloy substrate or a glass substrate such as crystallized glass or tempered glass is more suitable, and a Ni-P plated aluminum alloy substrate is particularly suitable.

  According to the substrate manufacturing method of the present invention, an effect that a memory hard disk or a semiconductor element in which the fine waviness of the polished object is significantly reduced can be manufactured.

(Polished object)
As the substrate to be polished, a 95 mmφ aluminum alloy substrate having a thickness of 1.27 mm and a substrate surface roughness (Ra) of 1 nm was prepared by rough polishing a Ni-P plated substrate in advance with a polishing liquid containing an alumina abrasive. Polishing evaluation was performed.

Examples 1-13 and Comparative Examples 1-6
By adding and mixing the abrasives listed in Tables 1 and 2, hydrogen peroxide (H ₂ O ₂ ), 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) and the remaining water (ion exchange water), A polishing liquid composition having the composition described in Table 3 was prepared. As the mixing order, 35 wt% hydrogen peroxide was mixed in an aqueous solution obtained by diluting HEDP in water, then the remaining components were mixed, and finally the slurry was mixed with stirring so as not to gel the slurry of the abrasive. A composition was prepared. Next, using the obtained polishing composition with the polishing pad shown in Table 4, the substrate to be polished was polished under the following polishing conditions.

In Table 3,
HEDP is composed of 1-hydroxyethylidene-1,1-diphosphonic acid (Dequest 2010, manufactured by Solusia Japan),
H ₂ O ₂ is 35% by weight hydrogen peroxide (Asahi Denka),
Indicates.

In addition, the particle size distribution of the abrasive particles contained in the abrasive in the obtained polishing composition was determined according to the following method. The result is shown in FIG.
(Calculation method of average particle size and standard deviation)
Photographs obtained by observing abrasive particles with a JEOL transmission electron microscope (trade name “JEM-2000FX”, 80 kV, observation magnification 1 to 50,000 times) are taken into a PC with a scanner, and analysis software “WinRoof” sold by Mitani Corporation Is used to determine the equivalent circle diameter of each silica particle, which is used as the diameter, and 1000 or more silica particle data are analyzed, and based on that, the number-based average particle diameter (μ), Standard deviation (σ) was calculated.

[Polishing conditions]
Polishing tester: Double speed 9B polishing machine surface plate rotation speed: 32.5r / min
Slurry supply amount: 40 ml / min
Polishing load: 7.8 kPa
Number of substrates loaded: 10

[Measurement method of pore size of polishing pad]
The surface of the polishing pad to be measured was observed with a “Digital Microscope VH-D8000” (high magnification zoom lens VH-Z450) manufactured by KEYENCE, magnified 450 times, subjected to a depth synthesis process, and an image was taken into a file. Next, the pore diameter was measured with image analysis software WinROOF (Mitani Corporation) on a PC using the captured image. The average value of the major axis and the minor axis when one pore is regarded as an ellipse was defined as the pore diameter, and this was performed for 100 or more pores, and the average pore diameter and the maximum value of the pore diameter were calculated.

  The surface of the obtained polishing substrate was measured for micro-waviness according to the following method, and the results are shown in Table 5.

[Measurement method of micropits]
The differential interference microscope observation [metal microscope “BX60M” (manufactured by Olympus Kogyo Co., Ltd.), magnification 50 × (eyepiece 10 ×, objective lens 5 ×)] shows a line as shown in FIG. The number of micropits was counted while scanning AB, CD, EF, and GH, and the number per side was calculated.

[Measurement of micro swell]
Measure the short wavelength undulation and long wavelength undulation under the following conditions for 2 points (total 4 points) at 180 ° intervals using the “New View 200” manufactured by Zygo, and the average of the measured values at the 4 points The value was calculated as the short wavelength waviness or long wavelength waviness of one substrate.
Objective lens: 2.5x Michelson
Zoom ratio: 0.5 times Filter: Band Pass
Filter type: FFT Fixed
Measurement wavelength:
・ Short wavelength swell: Filter High Wavelength 0.05mm
Filter Low Wavelength 0.50mm
・ Long wavelength swell: Filter High Wavelength 0.50mm
Filter Low Wavelength 5.00mm

[Measurement of surface roughness (TMS-Ra)]
The surface roughness (TMS-Ra) is attached by the manufacturer of the measuring instrument using a light scattering type surface roughness measuring instrument: TMS-2000RC (manufactured by Schmitt Measurement Systems, Inc.). Measured according to instructions. Specifically, with the measuring device, the substantially entire surface area of the surface and back surface of the object to be polished was measured in the measurement spatial wavelength region of 0.88 to 7.8 μm, and the surface roughness (TMS-Ra) value (Å )

[Determination of carrier noise]
From immediately after the start of polishing until the end of polishing, the sound generated from the periphery of the rotating platen (carrier) of the polishing tester was evaluated according to the following evaluation criteria to determine whether carrier squeak occurred. A symbol indicates that no carrier noise has occurred, and a triangle indicates that carrier noise has occurred.

Evaluation criteria ○: Normal sliding sound at the time of polishing is recognized Δ: Frictional noise that is not the sliding sound is recognized

  From the results of Tables 3 to 5, in Examples 1 to 13 using a polishing pad having a surface member having an average pore diameter of 0.01 to 35 μm, Comparative Examples 1 to 1 having an average pore diameter of 41.4 μm were used. Compared to 6, it can be seen that polishing for reducing both short wavelength waviness and long wavelength waviness can be performed in a short time.

Claims (13)

A suede type comprising a polishing composition comprising an abrasive and water, and at least a base layer and a foamed surface layer, having an average pore diameter of 1 to 25 μm and a maximum pore diameter of 60 μm or less A method of manufacturing a memory hard disk substrate using a polishing pad having a surface member made of polyurethane, wherein the abrasive is represented by the formula (16):
σ> 0.9067 × r ^{+ 0.588} (16)
(Wherein r represents the number-based average particle diameter (nm), and σ represents the number-based standard deviation (nm))
For a memory hard disk, comprising an abrasive having a particle size distribution represented by the formula (first component) and the first component and another abrasive (second component) having an average particle size and / or standard deviation different by 10% or more. A method for manufacturing a substrate.   The content of particles having a particle size of 5 to 120 nm in the total amount of the abrasive is 50% by volume or more, and small particles having a particle size of 5 nm to less than 40 nm are used as the abrasive with respect to the total amount of particles having a particle size of 5 to 120 nm. 10 to 100% by volume, medium-sized particles having a particle size of 40 nm to less than 80 nm are contained in an amount of 0 to 70% by volume based on the total amount of particles having a particle size of 5 to 120 nm, and large particles having a particle size of 80 to 120 nm. The method for producing a substrate according to claim 1, wherein the diameter particles are contained in an amount of 0 to 40% by volume based on the total amount of particles having a particle diameter of 5 to 120 nm.   The method for producing a substrate according to claim 1, wherein the abrasive is silica.   The manufacturing method of the board | substrate in any one of Claims 1-3 in which polishing liquid composition contains an oxidizing agent further.   The manufacturing method of the board | substrate of Claim 4 whose content of an oxidizing agent is 0.01 to 5 weight% in polishing liquid composition.   The manufacturing method of the board | substrate in any one of Claims 1-3 in which polishing liquid composition contains an acid and / or its salt further.   The method for producing a substrate according to claim 6, wherein the acid contains an inorganic acid and / or an organic phosphonic acid.   The manufacturing method of the board | substrate of Claim 6 or 7 whose content of an acid and its salt is 0.0025 to 1 weight% in polishing liquid composition.   The manufacturing method of the board | substrate in any one of Claims 1-8 whose content of an abrasive | polishing material is 1 to 15 weight% in polishing liquid composition.   The manufacturing method of the board | substrate in any one of Claims 1-9 whose flow volume of polishing liquid composition is 40-130 cc / min.   The manufacturing method of the board | substrate in any one of Claims 1-10 whose board | substrate is a Ni-P plated aluminum alloy board | substrate. A suede type comprising a polishing composition comprising an abrasive and water, and at least a base layer and a foamed surface layer, having an average pore diameter of 1 to 25 μm and a maximum pore diameter of 60 μm or less A method of polishing a memory hard disk substrate using a polishing pad having a polyurethane surface member, wherein the polishing material is represented by the formula (16):
σ> 0.9067 × r ^{+ 0.588} (16)
(Wherein r represents the number-based average particle diameter (nm), and σ represents the number-based standard deviation (nm))
For a memory hard disk, comprising an abrasive having a particle size distribution represented by the formula (first component) and the first component and another abrasive (second component) having an average particle size and / or standard deviation different by 10% or more. A method for polishing a substrate. A suede type comprising a polishing composition comprising an abrasive and water, and at least a base layer and a foamed surface layer, having an average pore diameter of 1 to 25 μm and a maximum pore diameter of 60 μm or less A method for reducing micro-waviness of a memory hard disk substrate using a polishing pad having a surface member made of polyurethane, wherein the abrasive is represented by formula (16):
σ> 0.9067 × r ^{+ 0.588} (16)
(Wherein r represents the number-based average particle diameter (nm), and σ represents the number-based standard deviation (nm))
For a memory hard disk, comprising an abrasive having a particle size distribution represented by the formula (first component) and the first component and another abrasive (second component) having an average particle size and / or standard deviation different by 10% or more. A method for reducing the fine waviness of a substrate.

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