CN105008293A - Method for manufacturing glass substrate for information recording medium - Google Patents

Method for manufacturing glass substrate for information recording medium Download PDF

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Publication number
CN105008293A
CN105008293A CN201480009973.XA CN201480009973A CN105008293A CN 105008293 A CN105008293 A CN 105008293A CN 201480009973 A CN201480009973 A CN 201480009973A CN 105008293 A CN105008293 A CN 105008293A
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China
Prior art keywords
glass
melten glass
glass substrate
cooling
information recording
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CN201480009973.XA
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CN105008293B (en
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梶田大士
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Hoya Corp
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Hoya Corp
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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B18/00—Shaping glass in contact with the surface of a liquid
    • C03B18/02—Forming sheets
    • C03B18/18—Controlling or regulating the temperature of the float bath; Composition or purification of the float bath
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B18/00—Shaping glass in contact with the surface of a liquid
    • C03B18/02—Forming sheets
    • C03B18/20—Composition of the atmosphere above the float bath; Treating or purifying the atmosphere above the float bath
    • C03B18/22—Controlling or regulating the temperature of the atmosphere above the float tank
    • 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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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacturing Of Magnetic Record Carriers (AREA)

Abstract

A method for manufacturing a glass substrate for an information recording medium, using a float process, wherein molten glass is floated on the surface of molten tin melted by heating in a float bath (1300), the temperature of the molten glass at a viscosity of log[eta]=4.0 (dPa.s) is 1100 DEG C or higher, the internal temperature of the clarifier tank is the liquidus temperature (TL) of the molten glass or higher, and a step for cooling the molten glass at a rate of temperature decrease of 50 DEG C per minute or more in the float bath (1300) is included. At the step for cooling the molten glass, cooling of the molten glass is started from a cooling start position that is at least 50 cm ahead in the flow direction of the molten glass from the position at which the molten glass flows into the float bath. The viscosity of the molten glass at the cooling start position is log[eta]=3.6 (dPa.s) or less, and cooling is performed at a rate of 50 DEG C per minute or more until the viscosity of the molten glass reaches log[eta]=4.0 (dPa.s) or more.

Description

The manufacture method of glass substrate for information recording medium
Technical field
The present invention relates to the manufacture method of the glass substrate for information recording medium carried as a part for information recording carrier in the information record carriers such as hard disk drive (HDD:Hard Disk Drive).
Background technology
In recent years, the storage capacity along with HDD increases tremendously, the record area of the medium needing reduction 1 bit to use essentially.Be proportional ground, recording magnetic-particle size also must miniaturization.But miniaturization can cause following problems: the energy that the magnetized direction of record remains a direction is diminished, is easily subject to the impact of heat.In order to make magnetized direction stablize, need to make medium become the high Fe-Pt magnetic material of coercive force from current as magneticsubstance widely used CoCr system alloy.
But in the film forming of Fe-Pt magnetic material, the arrangement of Fe, Pt atom becomes irregular, cannot obtain high-coercive force.Obtain high-coercive force in order to regularization, need the glass substrate after to film forming to implement the high-temperature heat treatment of about 600 DEG C essentially.
When obtaining this glass substrate, general use utilizes the manufacture method of the glass substrate of float glass process.Such as, in Japanese Unexamined Patent Publication 7-53223 publication (patent documentation 1), Japanese Unexamined Patent Publication 2001-357515 publication (patent documentation 2) and Japanese Unexamined Patent Publication 2003-36528 publication (patent documentation 3), disclose the manufacture method of the glass substrate for information recording medium utilizing float glass process.
Prior art document
Patent documentation
Patent documentation 1: Japanese Unexamined Patent Publication 7-53223 publication
Patent documentation 2: Japanese Unexamined Patent Publication 2001-357515 publication
Patent documentation 3: Japanese Unexamined Patent Publication 2003-36528 publication
Summary of the invention
The problem that invention will solve
As mentioned above, for Fe-Pt magnetic material essential need the high-temperature heat treatment implementing about 600 DEG C, therefore make the Tg becoming Heat-tolerant index of glass substrate be increased to the temperature of more than 600 DEG C, implement the high-temperature heat treatment of about 600 DEG C when Fe-Pt magnetic material film forming on the glass substrate.
Its result, although thermotolerance does not have problems, create information recording carrier (disk) only one side generation magnetic properties be deteriorated new problem.Contriver carries out deep result of study, has carried out composition analysis, found that containing Sn the errors present of this information recording carrier (disk).
In addition, contriver finds out reason, and result is known: when using the high Tg material being used for thermal assisted recording, temperature in floating trough operation in float glass process is high, temperature time shaping is high, and therefore molten tin (tin) is easily evaporated, and the Theil indices of the lower surface of glass becomes many.
For the recording density of existing disk, not problem containing tin in glass substrate, but need to carry out high-temperature heat treatment when forming the film forming of magnetospheric Fe-Pt alloy etc. of thermal assisted recording.In this high-temperature heat treatment, the tin of the lower surface of glass substrate spreads.Its result, the diffusion of known tin involves to magnetic film, and SNR (signal to noise ratio (signal-noise ratio) or the signal/noise ratio) quality of disk lower surface becomes unstable.Although can remove detin diffusion layer with grinding step in advance, Flatness and parallelism are deteriorated, thus not preferred.
Therefore, the present invention carries out to solve above-mentioned problem, its object is to provide a kind of manufacture method that can make the glass substrate for information recording medium of SNR stay in grade when using as information recording carrier.
For solving the scheme of problem
In the manufacture method based on glass substrate for information recording medium of the present invention, employ float glass process, wherein, according to melting groove, clarifying tank, floating trough and the order except cold pipeline, in above-mentioned melting groove, frit is made melten glass, make above-mentioned melten glass by above-mentioned clarifying tank, above-mentioned floating trough and above-mentioned except cold pipeline, be shaped to sheet glass, this manufacture method possesses following operation.
In above-mentioned floating trough, by heating, the surface of the molten tin of melting is floating above-mentioned melten glass, the temperature of above-mentioned melten glass when viscosity log η=4.0 (dPas) is more than 1100 DEG C, the internal temperature of above-mentioned clarifying tank is more than the liquidus temperature of above-mentioned melten glass, and this manufacture method is included in the operation cooling above-mentioned melten glass in above-mentioned floating trough with the cooling rate of more than 50 DEG C/min.
Cool the cooling starting above-mentioned melten glass in the operation of above-mentioned melten glass from the position that above-mentioned melten glass flows into the inside of above-mentioned floating trough in the cooling starting position of at least leading more than the 50cm of the flow direction of above-mentioned melten glass, the viscosity of the above-mentioned melten glass at above-mentioned cooling starting position place be log η=3.6 (dPas) below, the viscosity of above-mentioned melten glass reach log η=4.0 (dPas) below till during, cool with the speed of more than 50 DEG C/min.
In alternate manner, cool in the operation of above-mentioned melten glass to above-mentioned melten glass blowing gas.
In alternate manner, cool in the operation of above-mentioned melten glass and solid is contacted with above-mentioned melten glass.
In alternate manner, cool in the operation of above-mentioned melten glass and the temperature of the above-mentioned molten tin in above-mentioned floating trough is controlled.
In alternate manner, above-mentioned glass substrate for information recording medium is for the auxiliary glass substrate of heat.
The effect of invention
According to the present invention, a kind of manufacture method that can make the glass substrate for information recording medium of SNR stay in grade when using as information recording carrier can be provided.
Accompanying drawing explanation
Fig. 1 is the stereographic map that information record carrier is shown.
Fig. 2 illustrates the vertical view by the glass substrate 1 manufactured by the manufacture method of the glass substrate for information recording medium based on embodiment.
Fig. 3 observes sectional view along the direction of arrow of the III-III line in Fig. 2.
Fig. 4 illustrates to possess the vertical view of glass substrate 1 as the information recording carrier 10 of information recording carrier.
Fig. 5 observes sectional view along the direction of arrow of the V-V line in Fig. 4.
Fig. 6 is the schema of the manufacture method that glass substrate is shown.
Fig. 7 is the schematic diagram of the float glass process illustrated in glass substrate forming operation.
Fig. 8 is the figure of the molding procedure of glass substrate in the float glass process illustrated in embodiment floating trough used.
Fig. 9 is the figure of the molding procedure of glass substrate in the float glass process illustrated in another embodiment floating trough used.
Figure 10 is the figure of the molding procedure of glass substrate in the float glass process illustrated in another embodiment floating trough used.
Figure 11 is the figure of the viscograph that melten glass material is shown.
Figure 12 is the figure of the evaluation result of the HDD test run(s) illustrated in embodiment 1-8 and comparative example 1-4.
Embodiment
About based on embodiments of the present invention and each embodiment, be described with reference to the accompanying drawings.In the explanation of embodiment and each embodiment, when mentioning number, amount etc., apart from outside special situation about recording, scope of the present invention may not be defined in this number, amount etc.In the explanation of embodiment and each embodiment, to identical parts, suitable parts mark identical with reference to numbering, sometimes repeatedly do not carry out the explanation of repetition.
[embodiment]
(information record carrier 30)
With reference to Fig. 1, first information record carrier 30 is described.Fig. 1 is the stereographic map that information record carrier 30 is shown.Information record carrier 30 possesses by the glass substrate 1 manufactured by the manufacture method of the glass substrate for information recording medium (hereinafter also referred to as glass substrate) in embodiment as information recording carrier 10.
Specifically, information record carrier 30 possesses information recording carrier 10, housing 20, head-slider 21, suspension 22, arm 23, Z-axis 24, voice coil loudspeaker voice coil 25, voice coil motor 26, clamping part 27 and retaining screw 28.The upper surface of housing 20 is provided with spindle motor (not shown).
The information recording carriers such as disk 10 are clamped parts 27 and retaining screw 28 is fixed on above-mentioned spindle motor in the mode that can rotate.Information recording carrier 10 is driven in rotation with the rotating speed of such as thousands of rpm by this spindle motor.Details is described below with reference to Fig. 4 and Fig. 5, and information recording carrier 10 is by forming compressive stress layers 12 (with reference to Fig. 5) and magnetic recording layer 14 (reference Fig. 4 and Fig. 5) manufactures at glass substrate 1.
Arm 23 is installed on around Z-axis 24 in the mode that can shake.The suspension 22 being formed as leaf spring (socle girder) shape is installed in the front end of arm 23.In the mode sandwiching information recording carrier 10, head-slider 21 is installed in the front end of suspension 22.
In the side contrary with head-slider 21 of arm 23, voice coil loudspeaker voice coil 25 is installed.The magnet (not shown) that voice coil loudspeaker voice coil 25 is arranged on housing 20 is clamped.Voice coil motor 26 is formed by voice coil loudspeaker voice coil 25 and this magnet.
The electric current of regulation is supplied to voice coil loudspeaker voice coil 25.Arm 23 is shaken around Z-axis 24 by the effect of the electromagnetic force of the magnetic field generation by the electric current and above-mentioned magnet that flow to voice coil loudspeaker voice coil 25.By the shake of arm 23, suspension 22 and head-slider 21 also shake to arrow A R1 direction.Head-slider 21 moves back and forth at the radial direction of information recording carrier 10 on the surface of information recording carrier 10 He on the back side.The magnetic head (not shown) being arranged at head-slider 21 carries out seek operation.
Carry out the another side of this seek operation, head-slider 21 is subject to buoyancy by the airflow that produces together with the rotation of information recording carrier 10.By the balance of the elastic force (squeeze) of this buoyancy and suspension 22, head-slider 21 operates with certain suspension amount relative to the surface of information recording carrier 10.By this running, the magnetic head being arranged at head-slider 21 can carry out record and the regeneration of information (data) relative to the regulation track in information recording carrier 10.As the parts of the parts of configuration information recording medium 10 and the information record carrier 30 being equipped with glass substrate 1 as above form.
(glass substrate 1)
Fig. 2 illustrates the vertical view by the glass substrate 1 manufactured by the manufacture method of the glass substrate for information recording medium based on embodiment.Fig. 3 observes sectional view along the direction of arrow of the III-III line in Fig. 2.
As shown in Figures 2 and 3, the glass substrate 1 (glass substrate for information recording medium) being used for information recording carrier 10 (with reference to Fig. 4 and Fig. 5) as its part has major surfaces 2, major surfaces 3, inner circumferential end face 4, hole 5 and peripheral end face 6, and entirety is formed as discoid.Hole 5 is arranged to the mode that another major surfaces 3 is through according to from a major surfaces 2.Chamfered section 7 is formed respectively between major surfaces 2 and inner circumferential end face 4 and between major surfaces 3 and inner circumferential end face 4.Chamfered section 8 (chamfered edge portion) is formed between peripheral end face 6 and between major surfaces 3 and peripheral end face 6 at major surfaces 2.
The size of glass substrate 1 is such as 0.8 inch, 1.0 inches, 1.8 inches, 2.5 inches or 3.5 inches.It can be above-mentioned following or above-mentioned above inch dimension.From preventing damaged aspect, the thickness of glass substrate is such as 0.30mm ~ 2.2mm.The size of the glass substrate in present embodiment is that external diameter is about 64mm, internal diameter is about 20mm, thickness is about 0.8mm.The thickness of glass substrate refers to by average the calculated value of the value measured at the point of any more than 2 as the some object on glass substrate.From the aspect of the high rigidity of glass substrate, the Vickers' hardness of glass substrate 1 can be 610kg/mm 2above.
(information recording carrier 10)
Fig. 4 illustrates to possess the vertical view of glass substrate 1 as the information recording carrier 10 of information recording carrier.Fig. 5 observes sectional view along the direction of arrow of the V-V line in Fig. 4.
As shown in Figure 4 and Figure 5, information recording carrier 10 comprises glass substrate 1, compressive stress layers 12 and magnetic recording layer 14.Compressive stress layers 12 with the major surfaces 2 of cover glass substrate 1,3, the mode of inner circumferential end face 4 and peripheral end face 6 formed.Magnetic recording layer 14 is formed in the mode covering the regulation region on the major surfaces 2,3 of compressive stress layers 12.By forming compressive stress layers 12 on the inner circumferential end face 4 of glass substrate 1, in the formation hole, inner side 15 of inner circumferential end face 4.Utilize hole 15, information recording carrier 10 is fixed relative to the spindle motor be arranged on housing 20 (with reference to Fig. 1).
In the information recording carrier 10 shown in Fig. 5, the compressive stress layers 12 be formed on major surfaces 2 with compressive stress layers 12 both sides (two faces) be formed on major surfaces 3 are formed with magnetic recording layer 14.Magnetic recording layer 14 can only be arranged on the compressive stress layers 12 that is formed on major surfaces 2 (one side), also can be arranged on the compressive stress layers 12 that is formed on major surfaces 3 (one side).
Magnetic recording layer 14 is by being spun on the compressive stress layers 12 on the major surfaces 2,3 of glass substrate 1 by the heat-curing resin being dispersed with magnetic-particle and being formed (spin-coating method).Magnetic recording layer 14 can by formation such as the sputtering method implemented the compressive stress layers 12 on the major surfaces 2,3 of glass substrate 1 or electroless plating method.
About the thickness of magnetic recording layer 14, being about 0.3 μm ~ 1.2 μm when spin-coating method, is about 0.04 μm ~ 0.08 μm when sputtering method, is about 0.05 μm ~ 0.1 μm when electroless plating method.From the aspect of filming and densification, magnetic recording layer 14 can be formed by sputtering method or non-electrical plating method.
As the magneticsubstance for magnetic recording layer 14, use Fe-Pt magnetic material as the magnetic layer material being suitable for thermal assisted recording.
In order to improve the slip of magnetic head, can at the surface of magnetic recording layer 14 application of lubricating thinly.As lubricant, such as, can enumerate the material of PFPE (PFPE) the freonll-11 system equal solvent dilution as liquid lubricant.
At magnetic recording layer 14, can stratum basale or protective layer be set as required.Stratum basale in information recording carrier 10 can be selected according to the kind of magnetic film.As the material of stratum basale, the material of more than at least one be such as selected from the non-magnetic metal such as Cr, Mo, Ta, Ti, W, V, B, Al or Ni can be enumerated.
The stratum basale being arranged at magnetic recording layer 14 is not limited to individual layer, also can be by identical type or different types of multilayered structure long-pending layer by layer.Such as, can be the multi-layer substrate layers such as Cr/Cr, Cr/CrMo, Cr/CrV, NiAl/Cr, NiAl/CrMo or NiAl/CrV.
As the protective layer of the abrasion and corrosion that prevent magnetic recording layer 14, such as, can enumerate Cr layer, Cr alloy layer, carbon-coating, hydrocarbon layer, zirconia layer or silicon dioxide layer.These protective layers together can be formed with on-line sputter equipment continuously with stratum basale and magnetic film etc.These protective layers can be individual layer, or can for the multilayered structure be made up of identical type or different types of layer.
Above-mentioned protective layer can form other protective layer, or above-mentioned protective layer can be replaced and form other protective layer.Such as, replace above-mentioned protective layer, can in the material with alcohol series solvent dilution tetraalkoxysilane Dispersed colloidal silica particulate, and to be applied on Cr layer, and then to fire and form silicon-dioxide (SiO 2) layer.
(manufacture method of glass substrate)
Then, the manufacture method S100 of the schema shown in Fig. 6 to the glass substrate (glass substrate for information recording medium) in present embodiment is used to be described.The manufacture method S100 of the glass substrate in present embodiment possesses formed from plate glass operation S10, cutting action S20, end surface grinding operation S30, rough grinding operation S40, matting S50, chemical enhanced operation S60, precision lapping process S70 and cleans operation S80.
Magneticthin film formation process S200 is implemented to the glass substrate by obtaining through cleaning operation S80.By through magneticthin film formation process S200, obtain information recording carrier 10 (with reference to Fig. 4 and Fig. 5).Below, the details of each operation S10 ~ S80 of the manufacture method S100 of formation glass substrate is described successively.
(formed from plate glass operation S10)
First, in formed from plate glass operation S10, using melten glass material as material, utilize float glass process to manufacture sheet glass.The details of the float glass process of this enforcement as described later.
As the raw material of each composition of formation melten glass, use oxide compound corresponding separately, carbonate, nitrate, oxyhydroxide etc., weigh with desired ratio, fully mix in powder form, make Blend Stocks.Blend Stocks is such as put into and is heated in the melting groove of 1600 DEG C, carries out float glass process shaping, carry out annealing and forming sheet glass after melting clarification.
As the material of glass substrate, such as, can utilize amorphous glass, sintered glass ceramics.Also chemical intensification treatment can be implemented to glass substrate.In this situation, can be provided in the glass substrate for information recording medium of the intensity quality aspect excellence of glass baseplate surface.
(cutting action S20)
Referring again to Fig. 6, in cutting action S20, use cylindric diamond head to form endoporus at the central part of this glass substrate, mold circular glass substrate (boring core processing).Thereafter, utilize ciamond grinder to carry out grinding to inner circumferential end face and peripheral end face, implement the chamfer machining (shaping, chamfered edge) of regulation.After cutting action, carry out polishing process major surfaces being implemented to polishing (grinding), end surface grinding operation can be moved to afterwards.
(end surface grinding operation S30)
In end surface grinding operation S30, the abrasive brush with rifle brush batt material is utilized to grind the inner circumferential end face of glass substrate 1 and peripheral end face.Supply ground slurry between abrasive brush and each end face of glass substrate 1, rotate with the state making abrasive brush abut with each end face simultaneously.Glass substrate 1 being impregnated under the state in lapping liquid, rotate with the state making abrasive brush abut with each end face.
(rough grinding operation S40)
Glass substrate 1 after being polished for inner circumferential end face and peripheral end face, carries out coarse grinding to major surfaces 2,3 several times.Such as, the 1st rough grinding is divided into and this twice pair of major surfaces 2,3 of the 2nd rough grinding operation grinds.By improving the precision work precision of glass substrate 1 at leisure, can obtain having the glass substrate 1 on smoothness and the high surface of flatness.Be divided into when carrying out rough grinding twice, the main purpose of the 1st rough grinding operation is scar and distortion that removing remains in major surfaces 2,3, and the object of the 2nd rough grinding operation is that major surfaces 2,3 is finish-machined to mirror-like.
(matting S50)
After rough grinding operation S40, the clean utilizing acidic cleaning solution is implemented to glass substrate 1.The object of this clean be from the surface removing of glass substrate 1 be used as the rough grinding operation S40 of front operation in the cerium oxide of ground slurry, zirconium white or zirconium silicate any one.
Specifically, the grinding pad used from rough grinding operation S40 unloads the glass substrate after rough grinding 1, carries out etching while cleaning afterwards with the surface of scavenging solution to glass substrate 1 containing sulfuric acid and/or hydrofluoric acid etc.Be attached to the ground slurries such as the cerium oxide on the surface of glass substrate 1, zirconium white or zirconium silicate suitably to remove by the highly acid scavenging solution of sulfuric acid and/or hydrofluoric acid etc.Afterwards, acid scavenging solution is utilized to clean glass substrate 1.
Scavenging solution used in matting S50 is also different according to the chemical resistant properties of glass substrate 1, if sulfuric acid then preferably about 1% ~ 30% concentration, if hydrofluoric acid then preferably about 0.2% ~ 5% concentration.Use the cleaning of these scavenging solutions can while apply ultrasonic wave while carry out in the cleaning machine stockpiling the aqueous solution.The hyperacoustic frequency now used is preferably more than 78kHz.
(chemical enhanced operation S60)
Carry out chemical enhanced to glass substrate 1 after matting S50.As chemical enhanced liquid, such as, can use the mixed solution of saltpetre (50 % by weight) and sodium sulfate (50 % by weight).Chemical enhanced liquid is such as heated to 300 DEG C ~ 480 DEG C.The such as preheating of glass substrate 1 after cleaning is 300 DEG C ~ 480 DEG C.Glass substrate 1 such as floods 3 hours ~ 4 hours in chemical enhanced liquid.Chemical enhanced operation can be carried out after precision lapping process.
During dipping, in order to make major surfaces 2,3 entirety of glass substrate 1 carry out chemical enhanced, the mode be preferably kept at each end face according to multiple glass substrate 1, to flood with the state being accommodated in support.By being impregnated in chemical enhanced liquid by glass substrate 1, the alkalimetal ion (lithium ion and sodium ion) on the top layer of glass substrate 1 is replaced as the relative large chemical enhanced salt (sodium ion and potassium ion) of ionic radius in chemical enhanced liquid.Thus, the compressive stress layers of the thickness with 50 μm ~ 200 μm is such as formed on the top layer of glass substrate 1.
Made the surface of glass substrate 1 be reinforced by the formation of compressive stress layers, glass substrate 1 has good shock-resistance.Glass substrate 1 through chemical intensification treatment can be suitable for cleaning.Such as, glass substrate 1 after by sulfuric acid cleaned, uses pure water or IPA (Virahol) etc. to clean further.Chemical enhanced layer can be removed afterwards.
(precision lapping process S70)
After chemical enhanced operation S60, precise finiss process is implemented to glass substrate 1.The object of precision lapping process S70 is that the major surfaces of glass substrate 1 is finish-machined to mirror-like.In precision lapping process S70, utilize the precise finiss that twin grinder (with reference to Figure 11) carries out glass substrate 1 in the same manner as above-mentioned rough grinding operation S40.
In precision lapping process S70 and above-mentioned rough grinding operation S40, the grinding abrasive particle contained in the lapping liquid (slurry) used is different with the composition of the grinding pad used.In precision lapping process S70, compared with rough grinding operation S40, reduce the particle diameter of the grinding abrasive particle in the lapping liquid that the major surfaces 2,3 of the glass substrate 1 being formed with compressive stress layers is supplied, make the hardness of grinding pad become soft.
As the grinding pad for precision lapping process S70, such as, it is flexible foamed resin finish material.In precision lapping process S70, use free abrasive, comprise that to utilize take Ce as the abrasive particle of main component the 1st grinding step that carries out grinding and to utilize with Si be the 2nd grinding step that the abrasive particle of main component carries out grinding.
(cleaning operation S80)
After precision lapping process S70, scrub process is implemented to glass substrate 1.Specifically, the grinding pad used from precision lapping process S70 unloads the glass substrate 1 after precise finiss, afterwards while supply scavenging solution to the surface of glass substrate 1, the surface of swab to the glass substrate 1 being formed with compressive stress layers is utilized to clean.
Glass substrate 1 temporarily can be stored in water after unloading from the grinding pad of twin grinder.By preserving in water, can prevent the surface of glass substrate 1 after precise finiss from occurring dry, the amount of the foreign matters such as grinding dregs on the glass substrate 1 after being attached to precise finiss or free abrasive can be reduced simultaneously.After glass substrate 1 is preserved the specified time in water, glass substrate 1 is arranged at swab, glass substrate 1 is cleaned.
As scouring, such as, use the scavenging solution such as washing composition or pure water.PH for the scavenging solution cleaned can be less than more than 9.0 12.2.If within the scope of this, then easily adjust zeta-potential, can clean efficiently.As scouring, can carry out utilizing the scouring of washing composition and utilizing both scourings of pure water.By using washing composition and pure water, can more suitably clean glass substrate 1.Utilizing between the scouring of washing composition and the scouring utilizing pure water, rinsing process can carried out to glass substrate 1 further with pure water.
After cleaning, ultrasonic cleaning can be carried out further to glass substrate 1.After utilizing washing composition and pure water to clean, can carry out utilizing the ultrasonic cleaning of the reagent such as aqueous sulfuric acid further, utilize the ultrasonic cleaning of pure water, carry out the ultrasonic cleaning of washing composition, the ultrasonic cleaning based on IPA and/or the vapour seasoning etc. based on IPA.
As the manufacture method S100 of the glass substrate 1 in present embodiment, as above form.By using the manufacture method S100 of glass substrate 1, the glass substrate 1 of the present embodiment shown in Fig. 2 and Fig. 3 can be obtained.
(magneticthin film formation process S200)
For the major surfaces 2,3 (or any one major surfaces 2,3) of glass substrate 1 completing scrub process, form the magnetic recording layer that make use of Fe-Pt magnetic material.Thus, the information recording carrier 10 shown in Fig. 4 and Fig. 5 can be obtained.
(float glass process)
Below, with reference to Fig. 7 and Fig. 8, the float glass process in present embodiment is described.Fig. 7 is the schematic diagram of the float glass process illustrated in glass substrate forming operation, and Fig. 8 is the figure of the molding procedure of glass substrate in the floating trough illustrating that float glass process is used.
With reference to Fig. 7, set gradually in float glass process and melt groove 1100, clarifying tank 1200, floating trough 1300 and remove cold pipeline 1400.Import the temperature of frit more than about 1600 DEG C melted in groove 1100 and become melten glass, be admitted to clarifying tank 1200.
The melten glass being admitted to clarifying tank 1200 makes the temperature of melten glass be reduced to about 1300 DEG C ~ 1200 DEG C in clarifying tank 1200.While extrude with this state while in the process of carrying out, the bubble in melten glass is absorbed, disappears in melten glass.
The melten glass being reduced to about about 1100 DEG C flows in floating trough 1300.The shape of sheet glass is shaped in this floating trough 1300.Accumulate as molten bath in floating trough 1300 and have molten metal (being fused into liquid tin (tin)).The inside of floating trough 1300 is filled with atmosphere gas (mixed gas etc. of nitrogen and hydrogen) and is oxidized to prevent tin, utilizes electric heater etc. to control temperature.
The melten glass flowing into floating trough 1300 as oil swims on water face like that while on the liquid level of tin expansion while carry out.The relative density (such as 2.5) of melten glass is lighter than the relative density (such as 6.5) of tin, and therefore melten glass can float on the liquid level of tin.The face (lower surface) that melten glass contacts with tin is reflected by the horizontal plane of tin, becomes plane (horizontal plane).The upper surface of melten glass becomes horizontal plane because of gravity.Its result, melten glass is cooled to about about 600 DEG C, while be shaped to plane-parallel sheet glass.
For the sheet glass be transported to except cold pipeline 1400, in order to not make inside glass produce distortion because of temperature head, transport while cool lentamente.In ensuing operation, the sheet glass of specific dimensions is cut into by the sheet glass cooled except cold pipeline 1400.
In present embodiment, the melten glass in above-mentioned floating trough 1300 shaping in, for the viscosity of melten glass, log η=4.0 (dPas) left and right viscosity become benchmark.Melten glass is when under above-mentioned viscosity, its temperature is more than 1100 DEG C, and the evaporation of molten tin is fast, and the velocity of diffusion in melten glass increases.
Therefore, for the melten glass flowing out to the high temperature of floating trough 1300 more than liquidus temperature (TL), at least carry out cooling (quenching) with more than 50 DEG C/min to log η=4.0 (dPas) from log η=3.6 (dPas), thus the diffusion of molten tin in melten glass can be suppressed.The temperature of clarifying tank 1200 is more than liquidus temperature TL.This is because during for below liquidus temperature TL, in clarifying tank 1200, the crystallization of melten glass carries out, glass substrate becomes opaque (generation devitrification).
With reference to Fig. 8, the cooling of the melten glass flowing into floating trough 1300 is described.As mentioned above, accumulate as molten bath in the inside of floating trough 1300 and have molten tin 2000.The melten glass 100 extruded from clarifying tank 1200 flows out to the surface of molten tin 2000 from the influx 1310 of floating trough 1300.
The cooling starting melten glass 100 from the position (influx 1310) that melten glass 100 flows into floating trough 1300 inside in the cooling starting position of more than at least leading 50cm of the flow direction of melten glass (the size L in figure) to the cooling of melten glass flowing into floating trough 1300.This is because when being less than 50cm, melten glass 100 fully cannot spread (illustrated vertical direction) in floating trough 1300, likely detrimentally affect is produced to the gauge control of melten glass 100.
In present embodiment, in the cooling of melten glass, utilize gas blower 3100 blowing gas.The temperature of gas is that it is enough for the room temperature degree of 25 DEG C ~ 30 DEG C, also can use the gas utilizing refrigerating unit to be cooled to specified temperature.In order to not upset the atmosphere gas be filled in floating trough 1300, gas can the mixed gas etc. that use nitrogen and hydrogen same with atmosphere gas.
As shown in Figure 9, as other cooling unit, at cooling starting position configuration cooling roller 320, cooling roller 320 and the surface contact of melten glass can be made, melten glass cooled.By the surface contact of the solid that makes cooling roller 320 such and melten glass, the cooling of melten glass can be carried out efficiently.Cooling roller 320 can use SUS, pottery, refractory materials.By the internal recycling refrigeration agent at cooling roller 320, the cooling of melten glass more efficiently can be carried out.
As shown in Figure 10, as other cooling unit further, weir dike 2100 and weir dike 2200 can be set in the position of the certain intervals (L2) from cooling starting position (L1), for the temperature of the molten tin 2000 in the region surrounded by weir dike 2100 and weir dike 2200, utilize temperature control unit 2300 to be controlled to temperature lower than other region, carry out the cooling of melten glass 100.The temperature of molten tin 2000 controls the temperature treatment can enumerating the temperature treatment of the molten tin 2000 utilizing cooling unit or the management based on the amount of molten tin 2000.
(embodiment)
Use by the magnetic recording medium manufactured by the manufacture method of the glass substrate of embodiment 1-8 shown below and comparative example 1-4, carry out HDD test run(s).
The cooling of changing the melten glass in floating trough 1300 starts viscosity, cooling terminates viscosity, speed of cooling to make glass substrate.In all embodiments and comparative example, all employ glass composition is SiO 2be 63 % by weight, Al 2o 3be 2 % by weight, Na 2o is 3 % by weight, K 2o is 9 % by weight, MgO is 5 % by weight, CaO is 10 % by weight, ZrO 2be the glass of 8 % by weight.
Carried out the devitrification test of 3 hours, the liquidus temperature (TL) of this glass of result is 1180 DEG C.Tg (second-order transition temperature) is 670 DEG C.The mensuration of viscosity is measured by platinum ball crystal pulling method, obtains the viscograph shown in Figure 11.Temperature time log η=4.0 (dPas) is about 1125 DEG C.
Temperature in the clarifying tank 1200 of the front operation of floating trough 1300 is 1250 DEG C.Cooling starting position (L1) in floating trough 1300 is 50cm, and the glass viscosity of this position is log η=3.4 (dPas), and temperature is 1200 DEG C.The molten tin temperature of floating trough is 600 DEG C.
(embodiment 1)
In embodiment 1, the viscosity of the melten glass at cooling starting position (L1) place is log η=3.6 (dPas).
The cooling of melten glass 100 employs the gas blower 3100 shown in Fig. 8.The temperature of cooling gas is the room temperature degree of 25 DEG C ~ 30 DEG C, employs the gas identical with the atmosphere gas in floating trough 1300.
It is log η=4.0 (dPas) that the cooling of melten glass terminates viscosity, and cooling rate is 50 DEG C/min.
(embodiment 2)
In embodiment 2, the viscosity of the melten glass at cooling starting position (L1) place is log η=3.4 (dPas).The cooling of melten glass 100 is identical with embodiment 1.
It is log η=4.0 (dPas) that the cooling of melten glass terminates viscosity, and cooling rate is 50 DEG C/min.
(embodiment 3)
In embodiment 3, the viscosity of the melten glass at cooling starting position (L1) place is log η=3.6 (dPas).The cooling of melten glass 100 is identical with embodiment 1.
It is log η=4.2 (dPas) that the cooling of melten glass terminates viscosity, and cooling rate is 50 DEG C/min.
(embodiment 4)
In embodiment 4, the viscosity of the melten glass at cooling starting position (L1) place is log η=3.6 (dPas).The cooling of melten glass 100 is identical with embodiment 1.
It is log η=4.0 (dPas) that the cooling of melten glass terminates viscosity, and cooling rate is 100 DEG C/min.
(embodiment 5)
In embodiment 5, the viscosity of the melten glass at cooling starting position (L1) place is log η=3.4 (dPas).The cooling of melten glass 100 is identical with embodiment 1.
It is log η=4.2 (dPas) that the cooling of melten glass terminates viscosity, and cooling rate is 200 DEG C/min.
(embodiment 6)
In embodiment 6, the viscosity of the melten glass at cooling starting position (L1) place is log η=3.4 (dPas).
The cooling of melten glass 100 employs the cooling roller 320 shown in Fig. 9.Cooling roller 320 employs SUS304.The temperature of cooling roller 320 is 600 DEG C.
It is log η=4.2 (dPas) that the cooling of melten glass terminates viscosity, and cooling rate is 250 DEG C/min.
(embodiment 7)
In embodiment 7, the viscosity of the melten glass at cooling starting position (L1) place is log η=3.6 (dPas).
The cooling of melten glass 100 employs the method for the temperature of the molten tin 2000 shown in control Figure 10.The total length of floating trough 1300 is about 10m, arranges weir dike 2100, arrange weir dike 2200 in the position of L2=4m in the position of L1=1m.The temperature of the molten tin 2000 in the region surrounded by weir dike 2100 and weir dike 2200 is controlled to be 500 DEG C.The temperature of the molten tin 2000 in other region is 600 DEG C.
It is log η=4.2 (dPas) that the cooling of melten glass terminates viscosity, and cooling rate is 50 DEG C/min.
(embodiment 8)
In embodiment 8, the viscosity of the melten glass at cooling starting position (L1) place is log η=3.65 (dPas).The cooling of melten glass 100 is identical with embodiment 1.
(comparative example 1)
In comparative example 1, the viscosity of the melten glass at cooling starting position (L1) place is log η=3.6 (dPas).The cooling of melten glass 100 is identical with embodiment 1.
It is log η=3.9 (dPas) that the cooling of melten glass terminates viscosity, and cooling rate is 50 DEG C/min.
(comparative example 2)
In comparative example 2, the viscosity of the melten glass at cooling starting position (L1) place is log η=3.7 (dPas).The cooling of melten glass 100 is identical with embodiment 1.
It is log η=4.0 (dPas) that the cooling of melten glass terminates viscosity, and cooling rate is 50 DEG C/min.
(comparative example 3)
In comparative example 3, the viscosity of the melten glass at cooling starting position (L1) place is log η=3.6 (dPas).The cooling of melten glass 100 is identical with embodiment 1.
It is log η=4.0 (dPas) that the cooling of melten glass terminates viscosity, and cooling rate is 40 DEG C/min.
(comparative example 4)
In comparative example 4, the viscosity of the melten glass at cooling starting position (L1) place is log η=5.5 (dPas).The cooling of melten glass 100 is identical with embodiment 1.
It is log η=6.8 (dPas) that the cooling of melten glass terminates viscosity, and cooling rate is 200 DEG C/min.
Use the glass substrate obtained by above-described embodiment 1-8 and comparative example 1-4, manufacture magnetic recording media based on the schema shown in Fig. 6.As the magneticsubstance for magnetic recording layer, use Fe-Pt alloy as the magnetic layer material being suitable for thermal assisted recording, implement the thermal treatment of 600 DEG C × 1 hour, complete magnetic recording media.
The mensuration > of < read error number of times
By using the magnetic recording media of the glass substrate manufacture obtained by above-described embodiment 1-8 and comparative example 1-4 to be equipped in the information record carrier shown in Fig. 1, measuring read error number of times when working with 15000rpm, carrying out it and evaluating.The results are shown in Figure 12.
Evaluate 100 pieces in each embodiment and each comparative example, the sum of read error number of times is shown in Figure 12.Errors number is evaluated as " A " when being 0 ~ 2 time, is evaluated as " B " when errors number is 3 ~ 5 times, is evaluated as " F " when errors number is more than 6 times.Utilize SEM-EDX (energy dispersion type X-ray optical spectroscopy) to analyze wrong happening part, result confirms tin (Sn) by all disks that there occurs mistake.
The evaluation result of embodiment 1-embodiment 8 as shown in Figure 12 can confirm: the viscosity of melten glass at cooling starting position place be log η=3.6 (dPas) below, the viscosity of above-mentioned melten glass reach log η=4.0 (dPas) below during, can cool with the speed of more than 50 DEG C/min.
In comparative example 1, terminate viscosity too low, be log η=3.9 (dPas), therefore cool the diffusion terminating rear tin (Sn) and also carry out.In comparative example 2, beginning viscosity is too high, is log η=3.7 (dPas) that therefore the diffusion of tin (Sn) is carried out.In comparative example 3, cooling rate is slow, is 40 DEG C/min, therefore fully cannot suppresses the diffusion of tin (Sn).In comparative example 4, beginning viscosity is too high, is log η=5.5 (dPas) that therefore the diffusion of tin (Sn) is carried out.
Above, the manufacture method of the glass substrate for information recording medium according to the present embodiment, by suppressing the diffusion of the tin (Sn) of the lower surface of melten glass in the operation of the floating trough in float glass process, the SNR quality of the magnetic recording media of assisting for heat can be improved.
Embodiment of disclosure and embodiment are illustration in all respects, will be understood that and unrestricted.Scope of the present invention is not illustrated by above-mentioned explanation, but is illustrated by claims, comprises and all changes in the implication of claims equalization and scope.
The explanation of symbol
1 glass substrate, 2,3 major surfacess, 4 inner circumferential end faces, 5,15 holes, 6 peripheral end faces, 10 information recording carriers, 12 compressive stress layers, 14 magnetic recording layers, 20 housings, 21 head-sliders, 22 suspensions, 23 arms, 24 Z-axises, 25 voice coil loudspeaker voice coils, 26 voice coil motors, 27 clamping parts, 28 retaining screws, 30 information record carriers, 100 melten glass, 320 cooling rollers, 1100 melt groove, 1200 clarifying tanks, 1300 floating troughs, 1400 except cold pipeline, 2000 molten tin, 3100 gas blowers, 2100,2200 weir dikes, 2300 temperature control units.

Claims (5)

1. the manufacture method of a glass substrate for information recording medium, this manufacture method make use of float glass process, wherein, according to melting groove, clarifying tank, floating trough and the order except cold pipeline, in described melting groove, frit is made melten glass, make described melten glass by described clarifying tank, described floating trough and described except cold pipeline, be shaped to sheet glass
In described floating trough, by heating, the surface of the molten tin of melting is floating described melten glass,
The temperature of described melten glass when viscosity log η=4.0 (dPas) is more than 1100 DEG C,
The internal temperature of described clarifying tank is more than the liquidus temperature of described melten glass,
This manufacture method is included in the operation cooling described melten glass in described floating trough with the cooling rate of more than 50 DEG C/min,
Cool the cooling starting described melten glass in the operation of described melten glass from the position that described melten glass flows into the inside of described floating trough in the cooling starting position of at least leading more than the 50cm of the flow direction of described melten glass,
The viscosity of the described melten glass at described cooling starting position place be log η=3.6 (dPas) below, to the viscosity of described melten glass reach log η=4.0 (dPas) below till during cool with the speed of more than 50 DEG C/min.
2. the manufacture method of glass substrate for information recording medium as claimed in claim 1, wherein, cools in the operation of described melten glass to described melten glass blowing gas.
3. the manufacture method of glass substrate for information recording medium as claimed in claim 1, wherein, cools in the operation of described melten glass and solid is contacted with described melten glass.
4. the manufacture method of glass substrate for information recording medium as claimed in claim 1, wherein, cools in the operation of described melten glass and controls the temperature of the described molten tin in described floating trough.
5. the manufacture method of the glass substrate for information recording medium according to any one of Claims 1 to 4, wherein, described glass substrate for information recording medium is for the auxiliary glass substrate of heat.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112321153A (en) * 2019-08-05 2021-02-05 肖特股份有限公司 Thermoformed glass articles having low crystal fraction and methods and apparatus for making same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020031811A1 (en) * 2018-08-09 2020-02-13 Ａｇｃ株式会社 Method for manufacturing plate glass

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1283022A (en) * 1967-12-04 1972-07-26 Floatglas Gmbh Apparatus for the manufacture of flat glass
JP2000281365A (en) * 1999-04-01 2000-10-10 Nippon Sheet Glass Co Ltd Production of float type sheet glass and apparatus for production therefor
JP2008143746A (en) * 2006-12-11 2008-06-26 Nippon Electric Glass Co Ltd Method of manufacturing glass plate, apparatus therefor and glass substrate for flat panel display
CN101563298A (en) * 2006-11-07 2009-10-21 欧凯公司 Glass-ceramic flotation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1283022A (en) * 1967-12-04 1972-07-26 Floatglas Gmbh Apparatus for the manufacture of flat glass
JP2000281365A (en) * 1999-04-01 2000-10-10 Nippon Sheet Glass Co Ltd Production of float type sheet glass and apparatus for production therefor
CN101563298A (en) * 2006-11-07 2009-10-21 欧凯公司 Glass-ceramic flotation
JP2008143746A (en) * 2006-12-11 2008-06-26 Nippon Electric Glass Co Ltd Method of manufacturing glass plate, apparatus therefor and glass substrate for flat panel display

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112321153A (en) * 2019-08-05 2021-02-05 肖特股份有限公司 Thermoformed glass articles having low crystal fraction and methods and apparatus for making same
US11878939B2 (en) 2019-08-05 2024-01-23 Schott Ag Hot-formed, chemically prestressable glass articles with a low proportion of crystals and methods and devices for producing
CN112321153B (en) * 2019-08-05 2024-05-10 肖特股份有限公司 Thermoformed glass article having low crystal fraction and method and apparatus for making same
US11987523B2 (en) 2019-08-05 2024-05-21 Schott Ag Hot-formed, chemically prestressable glass articles with a low proportion of crystals and methods and devices for producing

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