CN104488028A - Information recording medium glass substrate, and manufacturing method of information recording medium glass substrate - Google Patents
Information recording medium glass substrate, and manufacturing method of information recording medium glass substrate Download PDFInfo
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- CN104488028A CN104488028A CN201380034239.4A CN201380034239A CN104488028A CN 104488028 A CN104488028 A CN 104488028A CN 201380034239 A CN201380034239 A CN 201380034239A CN 104488028 A CN104488028 A CN 104488028A
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
- G11B5/8404—Processes or apparatus specially adapted for manufacturing record carriers manufacturing base layers
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
- G11B5/739—Magnetic recording media substrates
- G11B5/73911—Inorganic substrates
- G11B5/73921—Glass or ceramic substrates
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- Manufacturing Of Magnetic Record Carriers (AREA)
- Magnetic Record Carriers (AREA)
Abstract
This manufacturing method of an information recording medium glass substrate is for manufacturing an information recording medium glass substrate which comprises a magnetic thin film layer formed on the primary surface of the glass substrate, and which is used in information recording mediums having a recording density on the magnetic recording surface of 600 Gbit/square inch or greater. When said information recording medium glass substrate has undergone alkali treatment involving immersion for 30 minutes in a pH11 sodium hydroxide solution at 40 DEG C, the average SiOH/Si value on the primary surface of the glass substrate is 0.20-0.50.
Description
Technical field
The present invention relates to the manufacture method of glass substrate for information recording medium and glass substrate for information recording medium.
Background technology
In the past, in the information recording carrier (disk recording medium) of computing machine etc., aluminium base or glass substrate was employed.These substrates are formed with laminated magnetic film, utilize magnetic head that laminated magnetic film is magnetized, thus recorded information in laminated magnetic film.
In recent years, in hard disk drive (HDD) device, recording density is densification more.Because of the densification of recording density, information recording carrier (carrier) with to float on an information recording medium and the gap (levitation height) of carrying out the magnetic head of the read-write of recording is contracted to a few about nm.
Along with levitation height diminishes, when information recording carrier is used in hard disk drive device, the problems such as read error when easily there are the data of Visitor Logs in medium and/or the head crash of write error and head crash dielectric surface.In order to suppress these problems, also reduced further by the size of the defect of substrate surface of allowing as information recording carrier, therefore, as glass substrate for information recording medium, the level of further pursuit surface smoothness, in order to suppress the ripple of foreign matter accompanying by glass baseplate surface, glass baseplate surface, various studying intensively is carried out to manufacture method.
On the other hand, in recent years, the memory capacity of HDD is further improved, and develops now the recording medium with following recording density: in the recording medium of 2.5 inches, and recording capacity is 500GB (one side 250GB), area recording density is more than 600Gbit/ square inch.In the recording medium of this high record density, even if when the glass substrate using flatness very high, known read error when sometimes also can there is data access and/or write error, analyze its reason, result is known is not the mistake that existing head crash causes.
For the problems referred to above, for the glass substrate after manufacture, comprise surface state and carry out probe, but find the defect of the main cause becoming read error and/or write error generation, not yet find concrete solution, but found that by probe, after magnetosphere is arranged to the glass substrate after manufacture, the deviation of the signal to noise ratio (S/N ratio) of magnetic signal can be produced, likely become the main cause that read error and/or write error occur.In the present invention, by the reduction of the deviation of the signal to noise ratio (S/N ratio) of this magnetic signal also referred to as electromagnetic conversion characteristics (SNR).
Main cause for the deviation of the signal to noise ratio (S/N ratio) of this magnetic signal is studied further, known following result.In general, the glass substrate of recording medium is temporarily sealed bale packing and is transported after fabrication, takes out afterwards and supplies to be coated with magnetospheric operation.Now, due to bale packing time, the time of transport, take out time the difference of condition, the uneven homogenize of surface state of glass substrate, or adhere to a small amount of particle sometimes, therefore in order to make surface state even, the higher clean-out system of the cleaning of aqueous slkali and so on can be used to clean, according to circumstances, the clean-out system with the characteristic making surface slightly dissolve also can be used to carry out cleaning (with reference to Japanese Unexamined Patent Publication 2006-127624 publication (patent documentation 1)).It is clear that, the deviation of the signal to noise ratio (S/N ratio) of above-mentioned magnetic signal is that the steady state (SS) of glass surface in the cleaning carried out before being about to be coated with this magnetosphere is impaired produced, even if check glass substrate itself after fabrication, also cannot distinguish main cause.
Prior art document
Patent documentation
Patent documentation 1: Japanese Unexamined Patent Publication 2006-127624 publication
Summary of the invention
The problem that invention will solve
As mentioned above, in the glass substrate that recording density is used in the hard disk drive device of more than 600Gbit/ square inch, although flatness, the spatter property of glass substrate itself are no problem, but as information recording carrier, there occurs the problem that electromagnetic conversion characteristics (SNR) reduces.
Present inventor has performed and repeatedly verify, found that, for the above-mentioned glass substrate implementing alkali treatment operation, when utilizing time-of-flight type ion microprobe (ToF-SIMS:Time-of-flight secondary ion massspectrometer) to measure the value of SiOH/Si, in the glass substrate that the value of SiOH/Si extremely reduces, there occurs the reduction of electromagnetic conversion characteristics (SNR) significantly.
Before formation laminated magnetic film, on the surface of glass substrate, when the value of SiOH/Si reduces, the polar group on the surface of glass substrate reduces, and therefore the absorption of laminated magnetic film (magnetosphere) is deteriorated.
Its result, known: the glass substrate reduced in the value of SiOH/Si defines in the information recording carrier of laminated magnetic film, (S/N compares: reduction SNR) can to cause signal to noise ratio (S/N ratio).
The present invention carries out in view of above-mentioned actual conditions, even if its object is to the glass substrate for information recording medium of reduction and the manufacture method of glass substrate for information recording medium that also can not cause signal to noise ratio (S/N ratio) (S/N ratio) when providing a kind of information recording carrier very high in the recording density for the recording density in magnetic recording face being more than 600Gbit/ square inch.
For solving the scheme of problem
On the first type surface of glass substrate, laminated magnetic film is formed with based on glass substrate for information recording medium of the present invention, this glass substrate for information recording medium recording density be used in magnetic recording face is the information recording carrier of more than 600Gbit/ square inch, wherein, for this glass substrate for information recording medium, when carry out by this glass substrate for information recording medium 40 DEG C, in the sodium hydroxide solution of pH11 when the dipping alkali treatment of 30 minutes, the mean value of the SiOH/Si of the above-mentioned first type surface of above-mentioned glass substrate is less than more than 0.20 0.50.
In alternate manner, the mean value of the SiOH/Si of the above-mentioned first type surface of above-mentioned glass substrate when carrying out above-mentioned alkali treatment is less than more than 0.20 0.45.
In alternate manner, relative to the mean value of the SiOH/Si of the above-mentioned first type surface of the above-mentioned glass substrate before above-mentioned alkali treatment, the rate of change of the mean value of the SiOH/Si of the above-mentioned first type surface of the above-mentioned glass substrate after above-mentioned alkali treatment is less than 20%.
Based on the manufacture method that the manufacture method of glass substrate for information recording medium of the present invention is the glass substrate for information recording medium described in above-mentioned any one, wherein, grinding step is carried out to the first type surface of disk-shaped glass parts, after above-mentioned grinding step, implement following process: make the above-mentioned disk-shaped glass parts after grinding contact 1 minute ~ 10 minutes with the hydrogeneous water of 0.1ppm ~ 1.4ppm, above-mentioned disk-shaped glass parts are made to contact 5 minutes ~ 20 minutes with the aqueous slkali of pH10.0 ~ 11.0 afterwards, make afterwards above-mentioned disk-shaped glass parts with 0.05% ~ 0.5% organic acid contact 5 minutes ~ 20 minutes, thereafter final matting is implemented.
Based on the manufacture method that the manufacture method of another glass substrate for information recording medium of the present invention is the glass substrate for information recording medium described in above-mentioned any one, wherein, grinding step is carried out to the first type surface of disk-shaped glass parts, after above-mentioned grinding step, implement following process: after making the above-mentioned disk-shaped glass parts after grinding contact 5 minutes ~ 20 minutes with the aqueous slkali of pH10.0 ~ 11.0, make above-mentioned disk-shaped glass parts with 0.05% ~ 0.5% organic acid contact 5 minutes ~ 20 minutes; Thereafter final matting is implemented.
Based on the manufacture method that the manufacture method of another glass substrate for information recording medium of the present invention is the glass substrate for information recording medium described in above-mentioned any one, wherein, grinding step is carried out to the first type surface of disk-shaped glass parts, after above-mentioned grinding step, implement following process: make the disk-shaped glass parts after grinding contact 3 minutes with the hydrogeneous water of 1.5ppm, make the disk-shaped glass parts after this grinding contact 5 minutes ~ 20 minutes with the aqueous slkali of pH10.0 ~ 11.0 afterwards; Thereafter above-mentioned final matting is implemented.
The effect of invention
According to the present invention, even if the glass substrate for information recording medium of reduction and the manufacture method of glass substrate for information recording medium that also can not cause signal to noise ratio (S/N ratio) (S/N ratio) when a kind of information recording carrier very high in the recording density for the recording density in magnetic recording face being more than 600Gbit/ square inch can be provided.
Accompanying drawing explanation
Fig. 1 is the stereographic map of the glass substrate for information recording medium in embodiment.
Fig. 2 is the stereographic map of the information recording carrier in embodiment.
Fig. 3 is the process flow diagram of the manufacture method of the information recording carrier illustrated in embodiment.
Fig. 4 is the figure of the evaluation result of the glass substrate for information recording medium that embodiment 1 ~ 3 and comparative example 1 ~ 2 are shown.
Embodiment
Below, embodiments of the present invention and embodiment are described.For identical or suitable part, sometimes mark identical reference label, and no longer repeat its explanation.In the embodiment and embodiment of following explanation, when mentioning number, quantity etc., except the situation of special instruction, scope of the present invention is not limited to this number, quantity etc.In the following embodiments, except the situation of special instruction, each inscape is not necessarily necessary to the present invention.
(structure of information recording carrier 1)
See figures.1.and.2, the structure of glass substrate for information recording medium 1G and information recording carrier 1 is described.Fig. 1 is the stereographic map of glass substrate for information recording medium 1G, and Fig. 2 is the stereographic map of information recording carrier.
As shown in Figure 1, the glass substrate for information recording medium 1G (hereinafter referred to as " glass substrate 1G ") used in information recording carrier 1 is the circular plate shape of the ring-type forming porose 11 at center.Glass substrate 1G has peripheral end face 12, inner circumferential end face 13, front first type surface 14 and reverse side first type surface 15.As glass substrate 1G, employ amorphous glass etc., such as, external diameter is about 65mm, and internal diameter is about 20mm, and thickness is about 0.8mm, and surfaceness about
below.
The inch dimension of glass substrate 1G is not particularly limited, the disc of 0.8 inch, 1.0 inches, 1.8 inches, 2.5 inches, 3.5 inches various glass substrate 1G as information recording carrier can be manufactured.
Owing to can successfully manage breaking of the glass substrate 1G that caused by falling impacts, the thickness of glass substrate 1G is preferably 0.30mm ~ 2.2mm.The thickness of so-called glass substrate 1G means herein, at the mean value of the value that the Arbitrary Digit point place as the some object on substrate measures.
As shown in Figure 2, information recording carrier 1 is formed with laminated magnetic film 23 on the front first type surface 14 of above-mentioned glass substrate 1G.In the example shown, only on front first type surface 14, form laminated magnetic film 23, but, also laminated magnetic film 23 can be set on reverse side first type surface 15.
As the formation method of laminated magnetic film 23, existing known method can be used, such as, can enumerate method that heat-curing resin that spin coating on substrate is dispersed with magnetic particle formed, by sputtering the method formed and the method formed by electroless plating.
The thickness that spin-coating method obtains is about 0.3 μm ~ about 1.2 μm, the thickness that sputtering method obtains is 0.04 μm ~ about 0.08 μm, the thickness that electroless plating method obtains is 0.05 μm ~ about 0.1 μm, for the viewpoint of filming and densification, the film based on sputtering method and electroless plating method is formed better.
As the magnetic material used in laminated magnetic film 23, be not particularly limited, existing known material can be used, but, in order to obtain high confining force, Co system alloy etc. is suitable, and Co system alloy is based on the Co that crystal anisotropy is high and adds Ni, Cr for the object adjusting residual magnetic flux density.In recent years, as the magnetic layer material being suitable for thermal assisted recording, employ the material of FePt system.
In order to improve the smoothness of magnetic head, lubricant can be applied thinly on the surface of laminated magnetic film 23.As lubricant, such as, can enumerate the lubricant will diluted as the PFPE (PFPE) of fluid lubricant with the solvent of freon system etc.
As required, basalis, protective seam can be set.Basalis in information recording carrier 1 can be selected according to magnetic film.As the material of basalis, such as, can enumerate the material of more than at least one selected from the nonmagnetic metal such as Cr, Mo, Ta, Ti, W, V, B, Al, Ni.
Basalis is not limited to individual layer, also can be set to the sandwich construction of stacked identical type or different types of layer.Such as, the multi-layer substrate layer of Cr/Cr, Cr/CrMo, Cr/CrV, NiAl/Cr, NiAl/CrMo, NiAl/CrV etc. can be set to.
As preventing the wearing and tearing of laminated magnetic film 23, the protective seam of corrosion, such as, Cr layer, Cr alloy-layer, carbon-coating, hydrogenated carbon layer, zirconia layer, silicon dioxide layer etc. can be enumerated.Protective seam by inline type sputter equipment, can be formed continuously together with basalis, magnetic film etc.Protective seam can be individual layer, or the sandwich construction be made up of identical type or different types of layer.
Other protective seam can be formed on above-mentioned protective seam, or, substitute above-mentioned protective seam and form other protective seam.Such as, substitute above-mentioned protective seam, on Cr layer, in the product obtained with the solvent dilution tetraalkoxysilane of alcohol system, Dispersed colloidal silica particulate applies, and fires further, forms silicon dioxide (SiO
2) layer.
As mentioned above, the glass substrate 1G of information recording carrier is circulated by the airtight bale packing of bale packing materials after fabrication, take out from bale packing materials afterwards, laminated magnetic film 23 etc. is set, before being about to, laminated magnetic film 23 grade is set, during in order to remove bale packing and/or transport time attachment molecule, or the unevenness of the surface state caused in order to the difference eliminated because of condition, utilizes aqueous slkali etc. to implement cleaning treatment.
Even if when implementing this alkali treatment, carry out by this glass substrate for information recording medium 40 DEG C, in the sodium hydroxide solution of pH11 during the dipping alkali treatment of 30 minutes, if the mean value of the SiOH/Si of the first type surface of above-mentioned glass substrate 14,15 is the glass substrate for information recording medium of less than more than 0.20 0.50, even if then when the information recording carrier that the recording density for the recording density in magnetic recording face being more than 600Gbit/ square inch is very high, the reduction of signal to noise ratio (S/N ratio) (S/N ratio) also fully can be suppressed.
(manufacturing process of glass substrate 1G)
Next, with reference to Fig. 3, the glass substrate 1G of present embodiment and the manufacture method of information recording carrier 1 are described.Fig. 3 is the process flow diagram of the manufacture method that glass substrate 1G and information recording carrier 1 are shown.
First, in " the glass melting operation " of step 10 (following, province is slightly " S10 ", also identical after step 11), make the glass blank melting of formation glass substrate.
In " the compression molding operation " of S11, by employing the mold pressing of upper die and lower die, melten glass blank is manufactured glass substrate.The glass ingredient used employs common alumina silicate glass.As the manufacture method of glass substrate, be not limited to shaping, also can be the cutting etc. from plate glass as known method, glass ingredient be also not limited thereto.
In " the 1st grinding process " of S12, grinding is carried out to two first type surfaces of glass substrate.1st grinding process uses the double-sided grinding device that make use of planetary gears to carry out.Specifically, from upper and lower, grinding disc is pressed on the two sides of glass substrate, to the first type surface supply grinding fluid of glass substrate, make their relatively movements to carry out grinding.By this grinding, obtain the glass substrate of the first type surface with general planar.
In " operation of coring " of S13, use cylindric diamond head, form hole at the central part of glass substrate, produce circular glass substrate.By ciamond grinder, grinding is carried out to the inner circumferential end face of glass substrate and peripheral end face, implement the chamfer machining of regulation.
In " the 2nd grinding process " of S14, same with above-mentioned 1st grinding process (S12), grinding is carried out to two first type surfaces of glass substrate.By carrying out the 2nd grinding process, can in advance the trickle concaveconvex shape of coring and being formed in first type surface in end face processing in front operation be removed.Consequently, the milling time of the first type surface in subsequent handling can be shortened.
In " the periphery grinding step " of S15, at the peripheral end face of glass substrate, carry out the mirror ultrafinish of grinding based on polish-brush (brush).As grinding abrasive particle now, employ the slurry comprising common cerium oxide abrasive particle.
In " the 1st polishing process " of S16, carry out first type surface grinding.The fundamental purpose of the 1st polishing process is corrected the cut and warpage that remain in first type surface in above-mentioned 1st grinding process and the 2nd grinding process (S12, S14).In the 1st polishing process, utilize the double-side polishing apparatus with planetary gears to carry out the grinding of first type surface.As lapping compound, employ common cerium oxide abrasive particle.
In " the chemical enhanced operation " of S17, form surface strengthen layer at the first type surface of glass substrate 1G.Specifically, in the mixed solution of the potassium nitrate (70%) and sodium nitrate (30%) that are heated to 300 DEG C, make glass substrate 1G contact about 30 minutes, carry out chemical enhanced thus.Consequently, the inner circumferential end face of glass substrate and the lithium ion of peripheral end face and sodion are replaced by the sodion in chemical reinforcing solution and potassium ion respectively, form compressive stress layers, make the first type surface of glass substrate and end face be strengthened thus.
In " the 2nd polishing process " of S18, implement first type surface grinding step.The object of the 2nd polishing process is, eliminates and to produce in the operation to above-mentioned and to remain in the tiny flaw etc. on first type surface, be finish-machined to mirror-like; Eliminate warpage, be finish-machined to desired flatness.In the 2nd polishing process, the double-side polishing apparatus with planetary gears is utilized to grind.In order to obtain even surface, use mean grain size for the colloidal silica of about 20nm is as lapping compound.
After having carried out above-mentioned " the 2nd polishing process ", for the alkali treatment being about to implement before glass substrate for information recording medium arranges laminated magnetic film, in order to improve the stability of glass substrate, suppress the reduction of the electromagnetic conversion characteristics (SNR) be coated with in the information recording carrier of laminated magnetic film, implement the pretreatment procedure of S19, this operation is for suppressing the activity of surface for alkali treatment of glass substrate.Specifically, when carry out by this glass substrate for information recording medium 40 DEG C, in the sodium hydroxide solution of pH11 when the dipping alkali treatment of 30 minutes, implementing pretreatment procedure, is less than more than 0.20 0.50 with the mean value of the SiOH/Si making the first type surface 14,15 of above-mentioned glass substrate.
In the operation contacted with aqueous slkali, by in advance the composition being present in the stripping from aqueous slkali of glass baseplate surface being removed, thus the mean value of the SiOH/Si after alkali treatment can be reduced, its result, even if when carrying out alkali treatment before being about to arrange laminated magnetic film, the effect of the reduction of the signal to noise ratio (S/N ratio) that also can be inhibited (S/N ratio).
But, if improve the pH of aqueous slkali herein or extend contact time, then become superfluous from the stripping of glass baseplate surface, the Ra of glass substrate becomes large, be difficult to the flatness be maintained as required for glass substrate for information recording medium, therefore be difficult to only by the operation contacted with aqueous slkali the mean value fully reducing the SiOH/Si after alkali treatment, therefore need to carry out with other process step combinations.As aqueous slkali, preferably use sodium hydroxide solution etc.
Herein, the operation contacted with hydrogeneous water has the effect that the surface charge of glass substrate is reduced.Therefore, the deterioration of the Ra of the glass substrate in alkali treatment can be suppressed, the stability of glass baseplate surface for alkali treatment afterwards can be improved simultaneously.
By the operation contacted with organic acid, can when not damaging the effect for obtaining making the Ra smoothing of the glass substrate worsened because contacting with aqueous slkali when alkali treatment stable.On the other hand, if excessively improve organic acid concentration or Long contact time, then the deterioration of Ra can be caused.As organic acid, such as, preferably use ascorbic acid, sulfaminic acid etc.Wherein, preferred ascorbic acid.
It should be noted that, " contact " in the solution in the present invention can be to glass baseplate surface spray solution, also can be impregnated in solution by glass substrate, is just not particularly limited as long as continue the stipulated time with the state of liquid comes into contact.
Next, in " final matting (the Final Cleaning) " of S20, implement the first type surface of glass substrate, the final cleaning of end face.Thus, remaining attachment is on the glass substrate removed.Final matting is the operation of finally carrying out of the manufacturing process at glass substrate, also comprises drying process aptly.
In present embodiment, the alkali treatment implemented before being about to make magnetic recording media by arranging laminated magnetic film to glass substrate for information recording medium, can the reduction of signal to noise ratio (S/N ratio) (S/N than) of magnetic recording media fully after restraint measure laminated magnetic film, as its index, utilize the mean value of SiOH/Si when specific alkali treatment implemented to glass substrate.
Specifically, in order to meet the scope of the mean value of the SiOH/Si after the alkali treatment in the present invention, adjusting above-mentioned pretreatment procedure, determining the manufacturing condition of glass substrate.Thus, can provide following glass substrate for information recording medium: it can reduce the deviation of the orientation of laminated magnetic film (magnetosphere), the deviation of this orientation is that the alkali treatment operation because carrying out before coating laminated magnetic film causes the activity on the surface of glass substrate to rise and produces; Even if when implement to arrange after alkali treatment laminated magnetic film and manufacturing information recording medium, also fully can suppress the reduction of signal to noise ratio (S/N ratio) (S/N than).
The manufacture method of the glass substrate in present embodiment is as above formed.By using the manufacture method of this glass substrate, the glass substrate 1G shown in Fig. 1 can be obtained.Thereafter, utilize the glass substrate 1G so obtained, obtain the information recording carrier 1 shown in Fig. 2.
As the laminated magnetic film film formation process in the manufacture of information recording carrier; after the cleaning of the glass substrate 1G obtained through above-mentioned operation; at two first type surfaces of glass substrate 1G; form the close binder be made up of Cr alloy, the soft ferromagnetic layer be made up of CoFeZr alloy, the tropism control basalis be made up of Ru, the vertical magnetism record layer be made up of CoCrPt alloy, the protective seam of C system, the film of lubricating layer that is made up of F system successively, produce the information recording carrier of vertical magnetism record mode thus.This structure is an example of the structure of vertical magnetism record mode, can form magnetosphere etc. as face internal information recording medium.Then, by implementing heat treatment step etc., information recording carrier 1 is completed.
(embodiment)
In the manufacture method of the glass substrate illustrated in the above-described embodiment, after having carried out " the 2nd polishing process ", as the pretreatment procedure (S19) of the activity on the surface of suppression glass substrate 1, carry out the process shown in embodiment 1 to embodiment 3, produce glass substrate 1G.After alkali treatment is implemented to manufactured glass substrate 1G, implement laminated magnetic film film formation process, produce information recording carrier.Similarly, the process shown in example 1 to comparative example 2 is also compared.
(embodiment 1)
In embodiment 1, after having carried out " the 2nd polishing process ", the hydrogeneous water of 1.5ppm has been utilized to implement rinsing in 3 minutes to glass substrate by spray.Thereafter, make glass substrate contact 5 minutes with the sodium hydroxide solution of pH10.5, make afterwards glass substrate with 0.1% ascorbic acid contact 15 minutes.Thereafter, pure water is utilized to carry out the final cleaning of glass substrate.
(embodiment 2)
In embodiment 2, after having carried out " the 2nd polishing process ", to glass substrate 1G, pure water has been utilized to implement rinsing by spray.Thereafter, make the sodium hydroxide solution of glass substrate 1G and pH10.5 contact 5 minutes, make afterwards glass substrate with 0.1% ascorbic acid contact 15 minutes.Thereafter, the cleaning of glass substrate that utilized pure water to carry out.
(embodiment 3)
In embodiment 3, after having carried out " the 2nd polishing process ", the hydrogeneous water of 1.5ppm has been utilized to implement rinsing in 3 minutes to glass substrate by spray.Thereafter, glass substrate is made to contact 5 minutes with the sodium hydroxide solution of pH10.5.Thereafter, the cleaning of glass substrate that utilized pure water to carry out.
(comparative example 1)
In comparative example 1, after having carried out " the 2nd polishing process ", make glass substrate with 0.1% ascorbic acid contact 15 minutes.Thereafter, the cleaning of glass substrate that utilized pure water to carry out.
(comparative example 2)
In comparative example 2, after having carried out " the 2nd polishing process ", pure water has been utilized to carry out the cleaning of glass substrate 1G.
The mensuration > of the value of the SiOH/Si after < alkali treatment
100 the glass substrate 1G obtained from enforcement above-described embodiment 1 ~ embodiment 3 and comparative example 1 ~ comparative example 2 select 10 glass substrate 1G, utilize each 3 places of time-of-flight type ion microprobe (ToF-SIMS) to the first type surface of each glass substrate 1G before alkali treatment to measure the value of SiOH/Si.
Thereafter, process 30 minutes with the sodium hydroxide solution (40 DEG C) of pH11,3 positions again utilizing time-of-flight type ion microprobe (ToF-SIMS) identical in the mensuration of the value with the SiOH/Si before alkali treatment measure the value of SiOH/Si respectively to the first type surface of each glass substrate 1G after alkali treatment.
Obtain the mean value of the value of the SiOH/Si after the alkali treatment under each evaluation point, using the value of the mean value of 10 samples as the SiOH/Si in each embodiment.
In addition, about the rate of change of the value of SiOH/Si, after the rate of change of the value obtaining the SiOH/Si after the alkali treatment under each measuring point relative to the value of the SiOH/Si before alkali treatment, obtain the mean value of the rate of change of the value of the SiOH/Si under each measuring point, using the rate of change of the mean value of 10 samples as the value of the SiOH/Si in each embodiment.
For glass substrate 1G, every a collection of manufacture 100, because the deviation of the evaluation in same batch is little, therefore have employed above-mentioned evaluation.
Electromagnetic conversion characteristics in < information recording carrier evaluates >
In electromagnetic conversion characteristics is evaluated, in embodiment 1 ~ comparative example 2, take out arbitrary 20 glass substrate 1G from alkali treatment test in untapped 90 samples, evaluate.Now, in order to corresponding with common circulation status, the glass substrate after manufacturing with bale packing materials temporarily sealing, preserves and takes out use after 1 day.
Before carrying out laminated magnetic film film formation process, as alkali treatment, utilize the sodium hydroxide solution of the pH11.5 of 30 DEG C in flowing water rinse bath, carry out 60 minutes dip treating.
In electromagnetic conversion characteristics is evaluated, by above-mentioned laminated magnetic film film formation process, laminated magnetic film formed to 20 glass substrate 1G and after obtaining information recording carrier, evaluate electromagnetic conversion characteristics.Specifically, the difference of the SNR for the information recording carrier as benchmark is obtained.
For information recording carrier electromagnetic conversion characteristics evaluation by inquiry based on magnetic head record-playback characteristic and carry out.Specifically, change recording frequency, change records density and tracer signal, read the reproduction output power of this signal, thus investigate.The recording density of information recording carrier is set to 650Gbit/ square inch.
As magnetic head, employ the perpendicular recording combination type magnetic head of perpendicular recording single pole head (record is used) and GMR magnetic head (reproduce and use) integration.If SNR value ~-0.1db is then evaluated as " A "; If-0.11db ~-0.20db is then evaluated as " B "; If-0.21 ~-0.30db is then evaluated as " C "; If-0.31db ~ be then evaluated as " D ".So-called SNR value represents the difference relative to prespecified reference value herein.
In order to be confirmed whether the mistake caused by electromagnetic conversion characteristics, utilize the optical system surface analytical equipment being representative with OSA (Optical Surface Analyzer: optical surface analyzer) being set as specific detection sensitivity, confirmed the spatter property of the glass substrate 1G before above-mentioned alkali treatment by defect inspection.About the count value of defect utilizing optical system surface analytical equipment, the quantity of the defects such as the attachment of each information recording carrier and/or pit is larger, then the detergency of presentation surface is more bad.
Evaluation result in the 1 ~ embodiment of embodiment shown in Fig. 43 and comparative example 1 ~ comparative example 2.Specifically, shown in Fig. 4: the value of the SiOH/Si of the glass substrate after (i) alkali treatment in embodiment 1 ~ embodiment 3 and comparative example 1 ~ comparative example 2; (ii) the SNR value (db) of the information recording carrier made in the embodiment 1 ~ 3 represented by the difference relative to the information recording carrier as benchmark and comparative example 1 ~ 2; (iii) rate of change of the SiOH/Si of the glass substrate before and after the alkali treatment in embodiment 1 ~ 3 and comparative example 1 ~ 2; (iv) the OSA count value in embodiment 1 ~ 3 and comparative example 1 ~ 2; The evaluation of (v) embodiment 1 ~ 3 and comparative example 1 ~ 2.
In embodiment 1, i the value of the SiOH/Si of the glass substrate after () alkali treatment is " 0.20 ", (ii) utilize in the glass substrate manufactured by glass substrate manufactured under the condition of embodiment 1, using the SNR value (db) of the information recording carrier represented by the difference relative to the information recording carrier as benchmark for " 0.12 (db) "; (iii) rate of change of the SiOH/Si of the glass substrate before and after alkali treatment is " 13% "; (iv) OSA count value is " 6 ".Its result, evaluates and obtains " A ".
In embodiment 2, i the value of the SiOH/Si of the glass substrate after () alkali treatment is " 0.46 ", (ii) utilize in the glass substrate manufactured by glass substrate manufactured under the condition of embodiment 2, using the SNR value (db) of the information recording carrier represented by the difference relative to the information recording carrier as benchmark for "-0.11 (db) "; (iii) rate of change of the SiOH/Si of the glass substrate before and after alkali treatment is " 17% "; (iv) OSA count value is " 12 ".Its result, is inferior to embodiment 1, evaluates and obtains " B ".
In embodiment 3, the value of the SiOH/Si of the glass substrate after (i) alkali treatment is " 0.50 "; (ii) utilize in the glass substrate manufactured by glass substrate that manufactures under the conditions of example 3, be "-0.21 (db) " as the SNR value (db) of the information recording carrier represented by the difference relative to the information recording carrier as benchmark; (iii) rate of change of the SiOH/Si of the glass substrate before and after alkali treatment is " 21% "; (iv) OSA count value is " 9 ".Its result, is inferior to embodiment 2, evaluates and obtains " C ".
In comparative example 1, the value of the SiOH/Si of the glass substrate after (i) alkali treatment is " 0.55 "; (ii) utilize in the glass substrate manufactured by glass substrate that manufactures under the condition of comparative example 1, be "-0.35 (db) " as the SNR value (db) of the information recording carrier represented by the difference relative to the information recording carrier as benchmark; (iii) rate of change of the SiOH/Si of the glass substrate before and after alkali treatment is " 21% "; (iv) OSA count value is " 10 ".Its result, is evaluated as " D ".
In comparative example 2, the value of the SiOH/Si of the glass substrate after (i) alkali treatment is " 0.14 "; (ii) utilize in the glass substrate manufactured by glass substrate that manufactures under the condition of comparative example 2, be "-0.48 (db) " as the SNR value (db) of the information recording carrier represented by the difference relative to the information recording carrier as benchmark; (iii) rate of change of the SiOH/Si of the glass substrate before and after alkali treatment is " 28% "; (iv) OSA count value is " 8 ".Its result, is evaluated as " D ".
As evaluation, " if A " ~ " C ", then can guarantee the credit as information recording carrier, therefore, if based on the result of embodiment 1 ~ embodiment 3 and comparative example 1 ~ comparative example 2, the mean value of the SiOH/Si of glass substrate utilizes time-of-flight type ion microprobe to record first type surface after being preferably used in alkali treatment is glass substrate manufactured under the condition of less than more than 0.20 0.46, from evaluating " A " and evaluating the viewpoint of " B ", be more preferably used in be less than more than 0.20 0.30 condition under manufactured by glass substrate.In embodiment and comparative example, represent that the measured value of the OSA of the spatter property of glass baseplate surface does not have in a substantial change, can confirm that Ra changing value can have an impact to SNR characteristic.
If utilize the information recording carrier of the glass substrate 1G employed in above-mentioned scope, even if the glass substrate for information recording medium of the reduction that also can not cause signal to noise ratio (S/N ratio) (S/N ratio) when being the hard disk drive device of more than 600Gbit/ square inch for recording density then can be provided.
Above, be illustrated, but should be realized that embodiments of the present invention and embodiment, embodiment of disclosure and embodiment are only in all respects and illustrate instead of restriction.Express, scope of the present invention is represented by claims, comprises the whole changes in the implication and scope that are equal to claims.
Symbol description
1 information recording carrier, 1G glass substrate for information recording medium, 11 holes, 12 peripheral end faces, 13 inner circumferential end faces, 14 front first type surfaces, 15 reverse side first type surfaces, 23 laminated magnetic films.
Claims (6)
1. a glass substrate for information recording medium, this glass substrate for information recording medium is formed with laminated magnetic film on the first type surface of glass substrate, it is the information recording carrier of more than 600Gbit/ square inch for the recording density in magnetic recording face, wherein
For this glass substrate for information recording medium,
When carry out by this glass substrate for information recording medium 40 DEG C, in the sodium hydroxide solution of pH11 when the dipping alkali treatment of 30 minutes, the mean value of the SiOH/Si of the first type surface of described glass substrate is less than more than 0.20 0.50.
2. glass substrate for information recording medium as claimed in claim 1, wherein, the mean value of the SiOH/Si of the described first type surface of described glass substrate when carrying out described alkali treatment is less than more than 0.20 0.45.
3. glass substrate for information recording medium as claimed in claim 1, wherein, relative to the mean value of the SiOH/Si of the described first type surface of the described glass substrate before described alkali treatment, the rate of change of the mean value of the SiOH/Si of the described first type surface of the described glass substrate after described alkali treatment is less than 20%.
4. a manufacture method for glass substrate for information recording medium, the manufacture method of its glass substrate for information recording medium according to any one of claims 1 to 3, wherein,
Grinding step is carried out to the first type surface of disk-shaped glass parts,
After described grinding step, implement following process: make the described disk-shaped glass parts after grinding contact 1 minute ~ 10 minutes with the hydrogeneous water of 0.1ppm ~ 1.4ppm, make described disk-shaped glass parts contact 5 minutes ~ 20 minutes with the aqueous slkali of pH10.0 ~ 11.0 afterwards, make afterwards described disk-shaped glass parts with 0.05% ~ 0.5% organic acid contact 5 minutes ~ 20 minutes; Thereafter final matting is implemented.
5. a manufacture method for glass substrate for information recording medium, the manufacture method of its glass substrate for information recording medium according to any one of claims 1 to 3, wherein,
Grinding step is carried out to the first type surface of disk-shaped glass parts,
After described grinding step, implement following process: after making the described disk-shaped glass parts after grinding contact 5 minutes ~ 20 minutes with the aqueous slkali of pH10.0 ~ 11.0, make described disk-shaped glass parts with 0.05% ~ 0.5% organic acid contact 5 minutes ~ 20 minutes; Thereafter final matting is implemented.
6. a manufacture method for glass substrate for information recording medium, the manufacture method of its glass substrate for information recording medium according to any one of claims 1 to 3, wherein,
Grinding step is carried out to the first type surface of disk-shaped glass parts,
After described grinding step, implement following process: make the disk-shaped glass parts after grinding contact 3 minutes with the hydrogeneous water of 1.5ppm, make the disk-shaped glass parts after this grinding contact 5 minutes ~ 20 minutes with the aqueous slkali of pH10.0 ~ 11.0 afterwards; Thereafter described final matting is implemented.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2012147404 | 2012-06-29 | ||
| JP2012-147404 | 2012-06-29 | ||
| PCT/JP2013/065354 WO2014002693A1 (en) | 2012-06-29 | 2013-06-03 | Information recording medium glass substrate, and manufacturing method of information recording medium glass substrate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104488028A true CN104488028A (en) | 2015-04-01 |
| CN104488028B CN104488028B (en) | 2017-10-27 |
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| CN201380034239.4A Active CN104488028B (en) | 2012-06-29 | 2013-06-03 | The manufacture method of glass substrate for information recording medium and glass substrate for information recording medium |
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| JP (1) | JP6021911B2 (en) |
| CN (1) | CN104488028B (en) |
| MY (1) | MY182274A (en) |
| SG (1) | SG11201408463YA (en) |
| WO (1) | WO2014002693A1 (en) |
Citations (4)
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|---|---|---|---|---|
| US20030188553A1 (en) * | 2002-04-08 | 2003-10-09 | Mann Larry G. | Direct bonding methods using lithium |
| CN1740388A (en) * | 2004-07-27 | 2006-03-01 | 富士电机电子设备技术株式会社 | Method of manufacturing a disk substrate for a magnetic recording medium |
| WO2008029895A1 (en) * | 2006-09-06 | 2008-03-13 | Horiba, Ltd. | Glass electrode and sensitive glass for the glass electrode |
| JP2010248071A (en) * | 2010-07-30 | 2010-11-04 | Toyo Sasaki Glass Co Ltd | Highly washable glass molded article |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4479528B2 (en) * | 2004-07-27 | 2010-06-09 | 富士電機デバイステクノロジー株式会社 | Method of plating on glass substrate, method of manufacturing disk substrate for magnetic recording medium using the plating method, and method of manufacturing perpendicular magnetic recording medium |
| JP3926371B2 (en) * | 2005-02-10 | 2007-06-06 | 信越石英株式会社 | Silica glass plate and method for producing the same |
| JP2011175685A (en) * | 2008-06-27 | 2011-09-08 | Panasonic Corp | Method and apparatus for manufacturing multilayer information recording medium |
-
2013
- 2013-06-03 WO PCT/JP2013/065354 patent/WO2014002693A1/en active Application Filing
- 2013-06-03 MY MYPI2014703885A patent/MY182274A/en unknown
- 2013-06-03 SG SG11201408463YA patent/SG11201408463YA/en unknown
- 2013-06-03 JP JP2014522501A patent/JP6021911B2/en active Active
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030188553A1 (en) * | 2002-04-08 | 2003-10-09 | Mann Larry G. | Direct bonding methods using lithium |
| CN1740388A (en) * | 2004-07-27 | 2006-03-01 | 富士电机电子设备技术株式会社 | Method of manufacturing a disk substrate for a magnetic recording medium |
| WO2008029895A1 (en) * | 2006-09-06 | 2008-03-13 | Horiba, Ltd. | Glass electrode and sensitive glass for the glass electrode |
| JP2010248071A (en) * | 2010-07-30 | 2010-11-04 | Toyo Sasaki Glass Co Ltd | Highly washable glass molded article |
Also Published As
| Publication number | Publication date |
|---|---|
| JP6021911B2 (en) | 2016-11-09 |
| JPWO2014002693A1 (en) | 2016-05-30 |
| CN104488028B (en) | 2017-10-27 |
| MY182274A (en) | 2021-01-18 |
| SG11201408463YA (en) | 2015-02-27 |
| WO2014002693A1 (en) | 2014-01-03 |
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