CN103946920A

CN103946920A - Process for producing glass substrate for HDD, glass substrate for HDD, and magnetic recording medium for HDD

Info

Publication number: CN103946920A
Application number: CN201280042051.XA
Authority: CN
Inventors: 福本直之
Original assignee: Hoya Corp
Current assignee: Hoya Corp
Priority date: 2011-06-30
Filing date: 2012-06-27
Publication date: 2014-07-23
Anticipated expiration: 2032-06-27
Also published as: JPWO2013001797A1; JP5360331B2; WO2013001797A1

Abstract

Provided is a process for producing a glass substrate for HDDs which inhibits head crushing even when used in a magnetic recording medium for HDDs that is to be mounted in an HDD equipped with a DFH head mechanism. Also provided are a glass substrate for HDDs and a magnetic recording medium for HDDs. The process for producing a glass substrate for HDDs includes a chemical strengthening step in which a glass substrate is chemically strengthened by immersing the glass substrate in a liquid for chemical strengthening. In the chemical strengthening step, the increase in the circumferential-direction TIR of the glass substrate through the chemical strengthening step is regulated to 0.5 [mu]m or less by changing the attitude of the glass substrate within the chemical strengthening liquid in which the glass substrate is being immersed, and/or by flatting the temperature distribution of the chemical strengthening liquid, and/or by stirring the chemical strengthening liquid.

Description

Manufacture method, HDD glass substrate and the HDD magnetic recording media of glass substrate for HDD

Technical field

The present invention relates to manufacture method, HDD glass substrate and the HDD magnetic recording media of a kind of HDD glass substrate.

Background technology

Generally, use magnetic recording media as the known HDD of having of representational recording medium (hard disk drive: hard disk drive) of the information recording carrier with the recording layer that utilizes magnetic, light, optomagnetic etc. character.As the HDD substrate with magnetic recording media for the manufacture of HDD, be widely used aluminium base in the past.But, be accompanied by recent years the requirement that reduces head gimbal amount in order to improve recording density, the glass substrate that can realize the reduction of head gimbal amount is increasing as the ratio of HDD substrate, and this is because glass substrate surface smoothness compared with aluminium base is good, and few surface defects.

The HDD magnetic recording media that is equipped on the mobile devices such as notebook personal computer need to use the substrate of resistance to impact, and therefore, example as disclosed in Patent Document 1, is commonly used the glass substrate that has improved resistance to impact by implementing chemical enhanced processing.

But, in recent years, high density recordingization progress, for example estimating there will be the recording capacity of 1 recording medium of 2.5 inches is that 500GB, area recording density are HDD magnetic recording media more than 630Gb/ square inch.Thereupon, the improvement of a mechanism, also in progress, is called a mechanism of DFH (dynamic flying height: dynamic fly height) for known.DFH uses special metal in the installation site of magnetic head, makes the technology of magnetic head to the outstanding slight distance of recording medium by the thermal expansion of metal.In a this DFH mechanism, the gap of magnetic head and recording medium is little of several nm left and right, easily occurs because magnetic head is to the bad head collision (head crash) causing of the tracking on recording medium surface.

Look-ahead technique document

Patent documentation

Patent documentation 1: No. 2001-167427, Japanese Patent Publication communique JP

Summary of the invention

The object of the present invention is to provide a kind of being used in to possess the HDD of DFH mechanism HDD magnetic recording media upper, that area recording density is high as being mounted in, also can suppress the HDD glass substrate of head collision generation a manufacture method, utilize the HDD glass substrate of this manufacture method manufacture and use the HDD magnetic recording media of this HDD glass substrate.

; one aspect of the invention relates to the manufacture method of HDD glass substrate; this manufacture method comprises glass substrate be impregnated in to chemical enhanced treating fluid; to glass substrate is implemented to the chemical enhanced operation of chemical enhanced processing; wherein, making the recruitment of the circumferential TIR (total indicated runout: always indicate departure) of the glass substrate of chemical enhanced operation front and back is below 0.5 μ m.

Another aspect of the present invention relates to the HDD glass substrate that utilizes the manufacture method of above-mentioned HDD glass substrate to make.

The present invention relates in one aspect to the HDD magnetic recording media that forms recording layer and make on the first type surface of above-mentioned HDD glass substrate in addition.

Above-mentioned and other object of the present invention, feature and advantage can become clear by following detailed record and accompanying drawing.

Brief description of the drawings

Fig. 1 is the manufacturing procedure picture of the related HDD of embodiments of the present invention glass substrate.

Fig. 2 is the partial side view that represents the structure of the main portion of the twin grinder using in the 1st and the 2nd grinding step.

Fig. 3 be along the III-III line of Fig. 2 to view, be the vertical view of lower flat board and support.

Fig. 4 is the longitudinal section that represents the structure of the main portion of the Oscar buffing machine using in the 1st polishing process.

Fig. 5 (a) is the vertical view that disposes the lower polishing disk of the Oscar buffing machine of the annular clip of relaxing glass substrate chimeric, and Fig. 5 (b) is the amplification horizontal cross of the annular clip of relaxing glass substrate chimeric.

Fig. 6 (a), Fig. 6 (b), Fig. 6 (c) are the vertical views that represents the action of Oscar polishing buffing machine.

Fig. 7 (a) is the stereographic map for the support at chemical enhanced operation support glass substrate, and Fig. 7 (b) is the side view of support.

Fig. 8 (a), Fig. 8 (b), Fig. 8 (c), Fig. 8 (d) are the process flow diagrams of the chemical enhanced processing carried out in chemical enhanced operation in the past.

Fig. 9 (a) is the stereographic map that represents the surface configuration of chemical enhanced glass substrate before treatment, and Fig. 9 (b) is the stereographic map that has represented to carry out the surface configuration of chemical enhanced glass substrate after treatment in the past.

Figure 10 (a) is the height mapping graph (map) of chemical enhanced glass substrate first type surface before treatment, Figure 10 (b) is the height mapping graph that has carried out glass substrate first type surface chemical enhanced after treatment in the past, and Figure 10 (c) is the key diagram that the circumferential TIR of the glass substrate before and after chemical enhanced processing is compared to expression.

Figure 11 (a), Figure 11 (b), Figure 11 (c), Figure 11 (d), Figure 11 (e) are the process flow diagrams of the chemical enhanced processing (one of concrete grammar) carried out in the related chemical enhanced operation of embodiments of the present invention.

Figure 12 (a), Figure 12 (b), Figure 12 (c) are the height mapping graphs of the glass substrate first type surface for the effect that one of method by concrete obtains is described.

Figure 13 (a), Figure 13 (b), Figure 13 (c), Figure 13 (d) be the chemical enhanced processing carried out in the related chemical enhanced operation of embodiments of the present invention (concrete grammar two and three) process flow diagram.

Figure 14 (a), Figure 14 (b) be for illustrate by concrete grammar two or the height mapping graph of glass substrate first type surface of three effects that obtain.

Figure 15 is the stereographic map of the related HDD of embodiments of the present invention glass substrate.

Embodiment

With reference to accompanying drawing, embodiments of the present invention are described below.But the present invention is not limited to this embodiment.

The inventor is conceived in service at HDD, due to magnetic head week of recording medium rotational speed upwards enough large compared with the translational speed moving up in the footpath of recording medium, therefore,, in order to suppress the generation of head collision, importantly suppress the variation of the circumferential surface state of recording medium.And, based on this viewpoint, find that upwards little in week of recording medium as the TIR (total indicated runout) of the index of the surperficial flatness of recording medium is effective.Then, the inventor show that the chemical enhanced processing of carrying out for the raising of resistance to impact etc. makes the opinion that the circumferential TIR of glass substrate worsens and completed the present invention.

And, the inventor also draws following opinion and has completed the present invention,, the reason that chemical enhanced processing worsens the circumferential TIR of glass substrate is, the environment of sneaking into etc., surround glass substrate of temperature deviation, concentration deviation or the foreign matter of the chemical enhanced treating fluid of dipping glass substrate is different because various essential factors are different, and therefore the surface configuration of the glass substrate before and after chemical enhanced processing changes unevenly.

The manufacture method > of glass substrate for <HDD

The manufacture method of HDD glass substrate is described with reference to the process chart shown in Fig. 1.

[glass melting operation]

First,, in glass melting operation, make glass raw material melting.As the material of glass substrate, for example, can use with SiO ₂, Na ₂o, CaO are the soda-lime glass (soda lime glass) of major component; With SiO ₂, Al ₂o ₃, R ₂o (R=K, Na, Li) is the alumina silicate glass of major component; Borosilicate glass; Li ₂o-SiO ₂be glass; Li ₂o-Al ₂o ₃-SiO ₂be glass; R ' O-Al ₂o ₃-SiO ₂be glass (R '=Mg, Ca, Sr, Ba) etc.In these materials, alumina silicate glass or borosilicate glass are because resistance to impact, vibration resistance are good and especially preferred.

[molding procedure]

Then, in molding procedure, make the glass raw material of melting flow into counterdie, carry out impact briquetting by patrix and obtain discoideus glass substrate (being referred to as blank).In addition, blank is not limited to make by impact briquetting, also can be by making with the thin sheet glass of the formation such as glass tube down-drawing, float glass process of emery wheel cutting.

Glass substrate, the size of blank does not limit.For example can make external diameter and be the glass substrate of all size of 2.5 inches, 1.8 inches, 1 inch, 0.8 inch etc.On the thickness of glass substrate, also do not limit.For example can make the glass substrate of the various thickness such as 2mm, 1mm, 0.8mm, 0.63mm.

[heat treatment step]

Then, in heat treatment step, by alternately stacked the calibrator (setter) of the glass substrate of making by impact briquetting or cutting and heat-resistant component, and make its electric furnace through high temperature, promote thus the reduction of warpage or the crystallization of glass of glass substrate.

[the 1st grinding step]

Then, in the 1st grinding step, attrition process is carried out in two surfaces of glass substrate, the depth of parallelism, flatness and thickness to glass substrate carry out presetting.

[getting core manufacturing procedure]

Then, getting in core manufacturing procedure, the conglobate hole of central part shape of the glass substrate after the 1st grinding step.Perforate for example can grind to carry out by being used in core drill that cutting part possesses skive etc. etc.

[inside and outside footpath manufacturing procedure]

Then,, in the manufacturing procedure of inside and outside footpath, by for example peripheral end face and the interior all end faces to glass substrate grinds with the drum type emery wheel of adamas etc., carry out thus the processing of inside and outside footpath.

[the 2nd grinding step]

Then, in the 2nd grinding step, two surfaces of glass substrate are carried out to attrition process again, the depth of parallelism, flatness and thickness to glass substrate are finely tuned.

In above-mentioned the 1st grinding step and described the 2nd grinding step, as shown in Figures 2 and 3, can use the known muller (grindingmachine) 10 that is called as twin grinder that utilizes planetary gears.Twin grinder 10 possesses in parallel to each other the discoideus upper flat plate 11 and lower dull and stereotyped 12 of configuration up and down.This upper and lower flat board 11,12 rotates along opposite directions.At opposed each the diamond pellet (diamond pellet) 13,14 being pasted with respectively for the first type surface of grinding glass substrate of this upper and lower flat board 11,12.Between upper and lower flat board 11,12, be provided with multiple supports 17.Each support 17 be arranged at the axial central gear 15 of lower dull and stereotyped 12 rotation and lower dull and stereotyped 12 periphery with the annular wheel 16 of circular setting in conjunction with and rotate.On each support 17, be formed with multiple holes 18.Glass substrate chimeric being supported in each hole 18 of being relaxed.In addition, about glass substrate, diagram not in Fig. 2 and Fig. 3, but for example in Figure 15 label symbol 80 illustrated.Upper and lower flat board 11,12, central gear 15 and annular wheel 16 move by different drivings respectively.

The abrasive action of muller 10 is roughly carried out as follows.; in the time that upper and lower flat board 11,12 rotates along opposite directions, between diamond pellet 13,14 be in rotation on one side under the state that support 17 between upper and lower flat board 11,12 supporting multiple glass substrates on one side with respect to dull and stereotyped 11,12 rotation center along with lower dull and stereotyped 12 identical direction revolution.By the muller 10 to such action, between the diamond pellet 13 of upper flat plate 11 and glass substrate and provide lapping liquid between lower dull and stereotyped 12 diamond pellet 14 and glass substrate, carry out thus the grinding of glass substrate.

Using when this twin grinder 10, suitably adjust according to the grinding state of expecting that dull and stereotyped 11,12 pairs of glass substrates apply load and dull and stereotyped 11,12 rotating speed.Preferably making the load in the 1st and the 2nd grinding step is 60g/cm ²(5.88kPa) to 120g/cm ²(11.77kPa).In addition, preferably making dull and stereotyped 11,12 rotating speed is 10rpm to 30rpm left and right, and makes under the rotating ratio of upper flat plate 11 dull and stereotyped 12 slow 30% to 40% left and right of rotating speed.If increase dull and stereotyped 11,12 loads that apply and accelerate dull and stereotyped 11,12 rotating speed, amount of grinding increases.But in the time that load is excessive, surfaceness can be not good, in the time that rotating speed is too fast, flatness can be not good.In addition, if reduce dull and stereotyped 11,12 load and the rotating speed of the flat board 11,12 that slows down, amount of grinding reduces, and manufactures Efficiency Decreasing.

Finishing the time point of the 2nd grinding step, the large ripple of glass substrate, cracked, defects i.e.cracks are almost removed.In addition, the surface roughness Ra of the first type surface of glass substrate is preferably 0.2 μ m to 0.4 μ m left and right, and the flatness of first type surface is preferably 7～10 μ m.By being set as this surface state, can carry out efficiently the polishing in ensuing the 1st polishing process.

In addition,, in the 1st grinding step, remove roughly the large ripple of glass substrate, cracked, crackle etc. to can carry out efficiently the 2nd grinding step.Therefore, preferably in the 2nd grinding step, use roughness for #1300 mesh (mesh) is to the diamond pellet 13,14 of about #1700 mesh, in the 1st grinding step, use #800 mesh that roughness ratio the 2nd grinding step the is thick diamond pellet 13,14 to #1200 mesh left and right.At the time point of the 1st grinding step that is through with, it is 0.4 μ m to 0.8 μ m left and right that the surfaceness of the first type surface of glass substrate is preferably Ra, and the flatness of first type surface is preferably 10～15 μ m.

In addition, preferably after the 1st grinding step and/or after the 2nd grinding step, carry out residuing in for removing the surperficial lapping liquid of glass substrate, the matting of glass dust.

In addition the surfaceness of utilizing in present embodiment, is to measure the value of the scope gained of 1 μ mx1 μ m with atomic force microscope (digital instrument company (Digital Instruments) nanoscope processed).In addition, the flatness of utilizing in present embodiment is to measure the value of gained with flatness determinator, is the surperficial extreme higher position (Po) of glass substrate and the difference of height (Po-Vo value) of extreme lower position (Vo).

[end face polishing operation]

Then,, in end face polishing operation, the peripheral end face of the glass substrate with end face polishing machine to the 2nd grinding step that is through with and interior all end faces carry out polishing.

[the 1st polishing process]

Then,, in the 1st polishing process, polishing is carried out in two surfaces of glass substrate.In the 1st polishing process, carry out polishing with 20 pairs of glass substrates 80 of the Oscar buffing machine shown in Fig. 4 to Fig. 6 (Oscar polishing machine), to finally can obtain efficiently the shape of the related HDD of present embodiment glass substrate.The upper polishing disk 22 that Oscar buffing machine 20 possesses the lower polishing disk 21 of rotation and shakes at the superjacent air space along continuous straight runs (X ← → X) of lower polishing disk 21.And, between upper and lower polishing disk 21,22, configuration is contained in the interior glass substrate 80 through the annular clip 23 larger than the external diameter of glass substrate 80, make on one side glass substrate 80 rotations, carry out polishing with 21,22 pairs of glass substrates 80 of upper and lower polishing disk two-sided on one side.

In Oscar buffing machine 20, under the state being placed with between upper and lower polishing disk 21,22 as the glass substrate 80 of polishing object, polishing fluid is provided on one side, allow lower polishing disk 21 rotations that polishing disk 22 is rocked from side to side as shown in Figures 4 to 6 on one side, thus, glass substrate 80 is by upper and lower polishing disk 21,22 and polished.According to condition, can promote the rotation of glass substrate 80.Its result, can manufacture the glass substrate 80 of concentrically ringed point symmetry shape., can suppress the variation of the circumferential surface state of glass substrate 80.In the present embodiment, the glass substrate 80 taking external diameter as 2.5 inches (63.5mm), as example describes, does not still limit the size of glass substrate 80.

In the present embodiment, the diameter of upper and lower polishing disk 21,22 is 1000mm, is pasted with whippy suede (suede (suede) 24 of polishing disk 21 under only illustrating in Fig. 5 (a)) on opposed each face.The glass substrate 80 chimeric support of being relaxed in the annular clip 23 (internal diameter 65mm, external diameter 67mm, thickness 0.5mm) of manufacturing with resin material shown in Fig. 5 (b).It 100 is placed on the suede 24 of lower polishing disk 21.Then, use polishing disk 22 and clip glass substrate 80, what be provided as on one side polishing fluid contains ceria or colloid silicon (colloidal silica) mud (slurry) as abrasive particle (polishing material), make on one side lower polishing disk 21 from then make upper polishing disk 22 rocking from side to side as shown in Figures 4 to 6 in scope arbitrarily.Thus, in the interior rotation of annular clip 23, two surfaces are upwards polished in week by the relative motion of upper and lower polishing disk 21,22 for glass substrate 80.

[chemical enhanced operation]

(introduction)

Then,, in chemical enhanced operation, by being impregnated in to chemical enhanced treating fluid, glass substrate forms chemical enhanced layer (stressor layers) on first type surface, peripheral end face and interior all end faces of glass substrate., glass substrate is implemented to chemical enhanced processing.By form chemical enhanced layer on the first type surface of glass substrate, can prevent the roughened of the warpage of glass substrate or first type surface.By forming chemical enhanced layer on the peripheral end face at glass substrate and interior all end faces, can improve resistance to impact, vibration resistance and the thermotolerance etc. of glass substrate.

Chemical enhanced operation is undertaken by ion exchange process, ion exchange process is by glass substrate being impregnated in heated chemical enhanced treating fluid, and the alkali metal ion such as the alkali metal ion such as lithium ion, sodion and its large potassium ion of ratio of ionic radii that glass substrate comprises is replaced.The distortion producing because of the difference of ionic radius produces compression stress in the region of ion-exchange, and first type surface, peripheral end face and interior all end faces of glass substrate is by stressor layers, chemical enhanced layer is reinforced.The result that the surface of glass substrate is reinforced by stressor layers, the resistance to impact of glass substrate is further improved.

Chemical enhanced treating fluid is not particularly limited, can uses known chemical enhanced treating fluid.Conventionally, generally use the fuse salt that comprises potassium ion or comprise potassium ion and the fuse salt of sodion.As the fuse salt that comprises potassium ion, sodion, can enumerate nitrate, carbonate, sulfate or their the mixed melting salt of potassium or sodium.Wherein, from the viewpoint of the low distortion that can prevent glass substrate of fusing point, preferably use nitrate.

(chemical enhanced processing in the past)

Chemical enhanced processing is in the past roughly as follows.First,, as shown in Fig. 7 (a), use the support 30 for support glass substrate 80.Support 30 is the containers that open wide up and down, and multiple support bars 31 set up in parallel to each other.As shown in Fig. 7 (b), glass substrate 80 is supported at 3 by multiple support bars 31.Glass substrate 80 by 30, tens, a support is arranged in parallel to each other and is supported simultaneously with small gap.

As shown in Fig. 8 (a), the glass substrate 80 that is supported in support 30 is preheated to 300 DEG C with electric furnace 40.As shown in Fig. 8 (b), process prepare in liquid bath 50 potassium nitrate (60 quality %) mix with sodium nitrate (40 quality %) and dissolve after chemical enhanced treating fluid, be heated to 400 DEG C with well heater 51.Glass substrate after preheating 80 is flooded in chemical enhanced treating fluid approximately 20 minutes, on whole of glass substrate 80, form strengthening layer.As shown in Fig. 8 (c), the glass substrate of the chemical enhanced processing that is through with 80 is carried out coolingly for approximately 10 minutes to flooding in the warm water tank 60 of 70 DEG C being heated by well heater 61, as shown in Fig. 8 (d), take out from warm water tank 60 afterwards.

Now, the environment of sneaking into etc., surround glass substrate 80 of the temperature deviation of chemical enhanced treating fluid, concentration deviation or foreign matter is different because various essential factors are different, and therefore the surface configuration of the glass substrate 80 before and after chemical enhanced processing can not change equably.For example, before chemical enhanced processing as shown in Fig. 9 (a) glass substrate 80 of surface configuration general planar after chemical enhanced processing as shown in Fig. 9 (b) surface configuration deform.

Its result, as shown in Figure 10 (a), (b), (c), after chemical enhanced processing, the circumferential TIR of glass substrate 80 worsens.Figure 10 (a) is the height mapping graph of chemical enhanced glass substrate before treatment 80 first type surfaces 81 (with reference to Figure 15).As shown in the drawing, before chemical enhanced processing, the flatness of glass substrate 80 first type surfaces 81 is relatively good.Therefore,, as shown in solid line (a) in Figure 10 (c), the circumferential TIR of the first type surface 81 of glass substrate 80 is little.On the other hand, Figure 10 (b) is the height mapping graph of glass substrate chemical enhanced after treatment 80 first type surfaces 81 in the past.As shown in the drawing, after chemical enhanced processing, the surface configuration of the first type surface 81 of glass substrate 80 deforms.Therefore,, as shown in dotted line (b) in Figure 10 (c), the circumferential TIR of the first type surface 81 of glass substrate 80 increases.

In addition, the circumferential TIR of Figure 10 (c) is the value of the position that dots in Figure 10 (a) and Figure 10 (b).Particularly, be the value in the position apart from glass substrate 80 center 0.75R when the radius of glass substrate 80 is made as to R.

Described " the circumferential TIR of glass substrate " refers to, for example, by obtaining by least square method with the plane of the first type surface optimal fitting of glass substrate and in the time upwards measuring the height of first type surface of many places glass substrate week, height is the absolute value (P-V value) with the difference of the minimum point (V) of height below described plane at the peak above described plane (P).

The circumferential TIR of the first type surface 81 of glass substrate 80 for example can wait to measure in the following way: utilize white interference of light to measure the mode of surface configuration (for example " Optiflat " of Phase Shift Technology company system); Or by with respect to determined face tilt inject the mode (" the Flat Master FM100XRA " of for example TROPEL company system) that laser can obtain reflectivity higher compared with vertical incidence mode and also can measure for thick face shape.

Like this, knownly in the chemical enhanced processing of carrying out, the circumferential TIR of glass substrate 80 was worsened in order to improve the resistance to impact etc. of glass substrate 80 in the past.Its result, the circumferential surface state of glass substrate 80 significantly changes, and the bad head collision causing of tracking because of magnetic head easily occurs.

(the chemical enhanced processing of present embodiment)

Therefore, in the present embodiment, seek to avoid chemical enhanced processing that the circumferential TIR of glass substrate 80 is worsened.Particularly, seek to make the recruitment of circumferential TIR of the glass substrate 80 before and after chemical enhanced operation below 0.5 μ m.

Accordingly, because the recruitment of the circumferential TIR of the glass substrate 80 before and after chemical enhanced operation is below 0.5 μ m, therefore, the deterioration of the circumferential TIR of the glass substrate 80 that chemical enhanced processing causes is very restricted.Therefore, the circumferential TIR of the glass substrate 80 after chemical enhanced operation is suppressed to little value, and the variation of the circumferential surface state of glass substrate 80 is suppressed, because of being suppressed that the bad head causing of tracking of magnetic head collides.

In the present embodiment, preferably making the recruitment of the circumferential TIR of the glass substrate 80 of chemical enhanced operation front and back is below 0.3 μ m.This is because the deterioration of the circumferential TIR of the glass substrate 80 causing because of chemical enhanced processing is further restricted, because of further being suppressed of the bad head collision causing of tracking of magnetic head.

In the present embodiment, the circumferential TIR of glass substrate 80 is circumferential TIR in the position apart from glass substrate 80 center 0.75R in the time that the radius of glass substrate 80 is made as to R.

Accordingly, tool has the following advantages.That is, the circumferential TIR of same glass substrate has correlationship with the distance apart from the center of glass substrate, has from the center of glass substrate more laterally away from the circumferential larger trend of TIR.And, be the position in relative outside in the first type surface 81 of glass substrate 80 or the posting field of recording medium apart from the position of glass substrate 80 center 0.75R.Therefore, by the recruitment of the circumferential TIR of the position apart from glass substrate 80 center 0.75R is limited in below 0.5 μ m or below 0.3 μ m, tool has the following advantages: the whole of the first type surface 81 that the peripheral end of the first type surface of glass substrate 80 81 and interior all ends are included or whole at the posting field that the peripheral end of the posting field of recording medium and interior all ends are included, circumferentially the deterioration of TIR is very restricted, and occurring in wide scope of head collision is inhibited.

(one of concrete grammar)

Recruitment as the circumferential TIR that makes the glass substrate 80 before and after chemical enhanced operation is first concrete grammar below 0.5 μ m, can enumerate following method: in chemical enhanced operation, change the posture of the glass substrate 80 that impregnated in chemical enhanced treating fluid in chemical enhanced treating fluid.

Accordingly, can be acted on as follows.That is, do not changing the posture of glass substrate 80 in chemical enhanced treating fluid, result from surround glass substrate 80 environment due to various want thereby different, likely produce press glass substrate 80 the surperficial different change of shape in each position.On the other hand, by changing the posture of glass substrate 80 in chemical enhanced treating fluid, can eliminate this by the different change of shape in each position.Therefore, the surface configuration of the glass substrate 80 before and after chemical enhanced processing changes equably, is below 0.5 μ m thereby can easily make TIR recruitment.

For example, as shown in Figure 11 (a), the glass substrate 80 that is supported in support 30 is preheated to 300 DEG C with electric furnace 40.As shown in Figure 11 (b), process prepare in liquid bath 50 potassium nitrate (60 quality %) mix with sodium nitrate (40 quality %) and dissolve after chemical enhanced treating fluid, be heated to 400 DEG C with well heater 51.Glass substrate after preheating 80 is flooded in chemical enhanced treating fluid to approximately 10 minutes (dipping for the first time).After dipping 10 minutes, take out glass substrate 80 by each support 30 from processing liquid bath 50, make all glass substrates 80 as in figure with as shown in arrow with respect to 90 ° of the central rotations of glass substrate 80.After having changed like this posture of glass substrate 80, as shown in Figure 11 (c), again in chemical enhanced treating fluid, flood approximately 10 points of kinds (dipping for the second time).As shown in Figure 11 (d), the glass substrate of the chemical enhanced processing that is through with 80 is carried out coolingly for approximately 10 minutes to flooding in the warm water tank 60 of 70 DEG C being heated by well heater 61, as shown in Fig. 8 (e), take out from warm water tank 60 afterwards.

In this way, as shown in Figure 12 (a), by flooding for the first time, the surface configuration of glass substrate 80 deforms symmetrically with the line through glass substrate 80 center, and as shown in Figure 12 (b), by flooding for the second time, the posture of the glass substrate 80 in chemical enhanced treating fluid changes 90 ° with respect to glass substrate 80 center, therefore they work mutually, as shown in Figure 12 (c), eliminated by the surperficial different change of shape in each position of glass substrate 80.Its result, the recruitment of the circumferential TIR of the glass substrate 80 before and after chemical enhanced operation becomes below 0.5 μ m.

In addition, this example is the surface configuration of glass substrate and situation about changing symmetrical with the line through the center of glass substrate, i.e. situation about changing in the surface configuration of two place's glass substrates of 180 ° of opposed regulations of glass substrate.Be not limited to this, for example, the place only specifying in the surface configuration of glass substrate changes, glass substrate is rotated bit by bit with the angle that is less than 90 °, and get final product (for example altogether carrying out more than 3 times repeatedly dippings) at every turn in glass substrate being impregnated in to chemical enhanced treating fluid.

The aim that this circumferential TIR recruitment is one of concrete grammar below 0.5 μ m is, grasp in advance the change of shape of the glass substrate causing because of chemical enhanced processing, according to this change of shape, chemical enhanced processing is carried out eliminating this change of shape several times.

In addition, if possible, also can glass substrate 80 not taken out and change posture under the state impregnated in chemical enhanced treating fluid from processing liquid bath 50.

(concrete grammar two)

Recruitment as the circumferential TIR that makes the glass substrate 80 before and after chemical enhanced operation is second concrete grammar below 0.5 μ m, can enumerate in chemical enhanced operation, makes the method for the temperature distribution homogenization of chemical enhanced treating fluid.

Accordingly, the temperature deviation of the chemical enhanced treating fluid of dipping glass substrate 80 is minimized.Therefore, the environment that surrounds glass substrate 80 becomes the same, and the surface configuration of the glass substrate 80 before and after chemical enhanced processing changes equably, is below 0.5 μ m thereby can easily make TIR recruitment.

For example, as shown in Figure 13 (a), the glass substrate 80 that is supported in support 30 is preheated to 300 DEG C with electric furnace 40.As shown in Figure 13 (b), process prepare in liquid bath 50 potassium nitrate (60 quality %) mix with sodium nitrate (40 quality %) and dissolve after chemical enhanced treating fluid, be heated to 400 DEG C with well heater 51～55.Glass substrate after preheating 80 is flooded in chemical enhanced treating fluid approximately 20 minutes.Now, process liquid bath 50 around by multiple well heaters 51～54 are configured in equably, make the temperature distribution homogenization of chemical enhanced treating fluid.In addition,, by being arranged on the well heater 55 configuring in the circular port of central part of glass substrate 80, can make the Temperature Distribution further homogenising of chemical enhanced treating fluid with respect to glass substrate 80.As shown in Figure 13 (c), the glass substrate of the chemical enhanced processing that is through with 80 is carried out coolingly for approximately 10 minutes to flooding in the warm water tank 60 of 70 DEG C heating with well heater 61, as shown in Figure 13 (d), take out from warm water tank 60 afterwards.

In this way, glass substrate 80 impregnated in the chemical enhanced treating fluid of temperature distribution homogenization, and therefore, as shown in Figure 14 (a), (b), before and after chemical enhanced processing, the circumferential TIR deterioration of glass substrate 80 is suppressed.Figure 14 (a) is the height mapping graph of chemical enhanced glass substrate before treatment 80 first type surfaces 81, and Figure 14 (b) is the height mapping graph that utilizes two glass substrate chemical enhanced after treatment 80 first type surfaces 81 of this concrete grammar.As shown in the drawing, before and after chemical enhanced processing, the flatness of the first type surface 81 of glass substrate 80 maintains well.Its result, the recruitment of the circumferential TIR of the glass substrate 80 before and after chemical enhanced operation becomes below 0.5 μ m.

Making this circumferential TIR recruitment is the stabilization that two aim of concrete grammar below 0.5 μ m is the chemical reaction of seeking ion exchange process.

In addition, also can omit the well heater 55 in the circular port of central part that is disposed at glass substrate 80 according to situation.

(concrete grammar three)

Recruitment as the circumferential TIR that makes the glass substrate 80 before and after chemical enhanced operation is the 3rd concrete grammar below 0.5 μ m, can enumerate the method that stirs chemical enhanced treating fluid in chemical enhanced operation.

Accordingly, the concentration deviation of the chemical enhanced treating fluid of dipping glass substrate 80 is minimized.Therefore, the environment that surrounds glass substrate 80 becomes the same, and the surface configuration of the glass substrate 80 before and after chemical enhanced processing changes equably, is below 0.5 μ m thereby can easily make TIR recruitment.

For example, in described Figure 13 (b), make the well heater 55 in the circular port of the central part that is disposed at glass substrate 80 as stirring rod, carry out as shown by arrows in FIG. circular motion or rotation.

In this way, glass substrate 80 impregnated in the chemical enhanced treating fluid of CONCENTRATION DISTRIBUTION homogenising, and therefore, as shown in Figure 14 (a), (b), before and after chemical enhanced processing, the circumferential TIR deterioration of glass substrate 80 is suppressed.Figure 14 (a) is the height mapping graph of chemical enhanced glass substrate before treatment 80 first type surfaces 81, and Figure 14 (b) is the height mapping graph that utilizes three glass substrate chemical enhanced after treatment 80 first type surfaces 81 of this concrete grammar.As shown in the drawing, in the front and back of chemical enhanced processing, the flatness of the first type surface 81 of glass substrate 80 maintains well.Its result, the recruitment of the circumferential TIR of the glass substrate 80 before and after chemical enhanced operation becomes below 0.5 μ m.

Making this circumferential TIR recruitment is the stabilization that three aim of concrete grammar below 0.5 μ m is the chemical reaction of ion exchange process.

In addition, also can be according to situation, replace well heater 55 in the circular port of the central part that is disposed at glass substrate 80 and in the circular port of the central part of glass substrate 80 configuration do not there is the stirring rod of heating function.In addition, also can only leave well heater 51, and omit the multiple well heaters 52～54 that are disposed at the surrounding that processes liquid bath 50.In addition, be not limited to stir chemical enhanced treating fluid in the circular port of the central part of glass substrate 80, also can be outside the circular port of the central part of glass substrate 80, i.e. the chemical enhanced treating fluid of stirring around glass substrate 80.In addition, also can in the circular port of the central part of glass substrate 80 and outside circular port, stir chemical enhanced treating fluid.

[the 2nd polishing process]

Then,, in the 2nd polishing process, accurate polishing is further carried out in two surfaces of the glass substrate after chemical enhanced operation.In the 2nd polishing process, the Twp-sided polishing machine of twin grinder 10 similar structures that use in the 1st shown in use and Fig. 2 and Fig. 3 and the 2nd grinding step.

In the 2nd polishing process, replace diamond pellet 13,14, using than the soft hardness of suede using in the 1st polishing process is the soft polishing pad of 65 to 80 (Asker-C) left and right.This polishing pad for example preferably uses isocyanurate foam, suede.

As polishing fluid, can use identical with the 1st polishing process mud as abrasive particle (polishing material) such as ceria that contains.But in order to make the surface of glass substrate more level and smooth, the particle diameter that preferably uses abrasive particle is less and polishing fluid that deviation is few.For example preferably use the colloid silicon that is 40nm to 70nm using mean grain size to be scattered in water and to become slimy liquid as polishing fluid as abrasive particle (polishing material).The mixture ratio of preferred water and abrasive particle is roughly 1: 9 to 3: 7 left and right.

Preferably making upper and lower flat board is 90g/cm to the load of glass substrate ²(8.83kPa) to 110g/cm ²(10.8kPa).In addition, preferably making upper and lower dull and stereotyped rotating speed is 15rpm to 35rpm, and makes slow 30% to 40% left and right of rotating speed dull and stereotyped under the rotating ratio of upper flat plate.

By the polishing condition of suitable adjustment the 2nd polishing process, the flatness that can make the first type surface of glass substrate is below 3 μ m, makes the surface roughness Ra of first type surface of glass substrate little of 0.1nm.

Polished amount in the 2nd polishing process is preferably 2 μ m to 5 μ m.By polished amount being made as to this scope, can remove well that produce on the surface of glass substrate small chapped, the tiny flaw of ripple or small scar of producing and so in operation so far.

Like this, by being included in the polishing process that after chemical enhanced operation, polishing is carried out in the surface of glass substrate 80, the circumferential TIR of final glass substrate 80 is further diminished.Therefore, further being suppressed of head collision.

[matting]

Then,, in matting, the glass substrate after the 2nd polishing process is scrubbed.But, be not limited to scrub, as long as the surperficial cleaning method of the glass substrate after can cleaning polishing operation, can be just cleaning method arbitrarily.

As required to carried out hyperacoustic cleaning and dry processing by the glass substrate after scrubbing.Dry processing is to have removed and residued in the processing that makes the dry tack free of glass substrate after the surperficial cleaning fluid of glass substrate with IPA (isopropyl alcohol: isopropyl alcohol) etc.For example the glass substrate after scrubbing is carried out the bath matting of 2 minutes, remove the residue of cleaning fluid.Then, IPA matting is carried out 2 minutes, utilizes IPA to remove the surperficial water that residues in glass substrate.Finally, IPA vapour seasoning operation is carried out 2 minutes, utilizes IPA steam to remove and is attached to the surperficial aqueous IPA of glass substrate and makes it dry.

Dry processing as glass substrate is not limited thereto, can be also Rotary drying, air knife dry etc. be generally known drying means as the drying means of glass substrate.

[inspection operation]

Then, checking in operation, by visual check have or not glass substrate scar, break, the adhering to etc. of foreign matter.Cannot be by visual differentiation in the situation that, use optical surface analyzer (for example " OSA6100 " of KLA-TENCOL company system) to check.

By checking that glass substrate that operation is identified as non-defective unit is accommodated in special receiver in clean environment in order to avoid at surface attachment foreign matter etc., after carrying out vacuum packaging, dispatch from the factory with glass substrate as HDD.

Then, the HDD glass substrate of manufacturing in mode as above is described.As shown in figure 15, the related HDD of present embodiment is to be suppressed at the circumferential TIR of its first type surface 81 the high-quality HDD glass substrate that the variation of little value and circumferential surface state is inhibited with glass substrate 80.

Then, the HDD magnetic recording media that uses described HDD glass substrate 80 to manufacture is described.The related HDD magnetic recording media of present embodiment makes as the magnetic film of recording layer with formation on the first type surface 81 of glass substrate 80 at described HDD.Magnetic film can be formed on first type surface 81 directly or indirectly.Magnetic film can be formed at the single or double of glass substrate 80.

As the formation method of magnetic film, can use known method in the past, can enumerate for example by the heat-curing resin that disperses magnetic particle to form being spin-coated on to the method forming on glass substrate 80, the method forming by sputter or electroless plating etc.Thickness in spin-coating method is approximately 0.3 μ m～1.2 μ m left and right, thickness in sputtering method is 0.01 μ m～0.08 μ m left and right, thickness in electroless plating method is 0.01 μ m～0.1 μ m left and right, from the viewpoint of filming and densification, preferably forms film by sputtering method, electroless plating method.

Be not particularly limited as the magnetic material for magnetic film, can use known material in the past.Wherein, preferably use the Co that has added Ni or Cr as stock and taking adjustment relict flux density as object taking the high Co of crystal anisotropy in order to obtain high confining force to be associated gold etc.Particularly, preferably use CoPt, CoCr, CoNi, CoNiCr, CoCrTa, CoPtCr, CoNiPt, CoNiCrPt, CoNiCrTa, CoCrPtTa, CoCrPtB, the CoCrPtSiO etc. taking Co as major component.

Magnetic film can such as, for such as, cutting apart with nonmagnetic film (Cr, CrMo, CrV etc.) sandwich construction (CoPtCr/CrMo/CoPtCr, CoCrPtTa/CrMo/CoCrPtTa etc.) of having realized reducing noise.

Except above-mentioned magnetic material, can be also ferrite system or rare-earth iron series material or the magnetic particles such as Fe, Co, FeCo, CoNiPt are scattered in by SiO ₂, the particle etc. of structure in the nonmagnetic film that forms such as BN.

Magnetic film can be any form that records in inner face type and vertical-type.

In order to make sliding of magnetic head good, can coat thin lubricant on the surface of magnetic film.As lubricant, for example can enumerate and will dilute the lubricant that forms etc. as solvents such as PFPE (PFPE) the dichlorodifluoromethan systems (Freon-based) of fluid lubricant.

In the present embodiment, as required, except forming the magnetic film as recording layer, can also form basalis or protective seam.HDD selects according to magnetic film with the basalis in magnetic recording media.As the material of basalis, can enumerate at least one the above material in the group that nonmagnetic metal such as for example selecting free Cr, Mo, Ta, Ti, W, V, B, Al, Ni forms.In the case of the magnetic film taking Co as major component, from viewpoints such as the raisings of magnetic characteristic, be preferably Cr monomer or Cr alloy.Basalis is not limited to individual layer, the sandwich construction of the layer of the identical or different kind that can be also stacked.Can be for example the multi-layer substrate layers such as Cr/Cr, Cr/CrMo, Cr/CrV, NiAl/Cr, NiAl/CrMo, NiAl/CrV.

Protective seam forms for the wearing and tearing or the corrosion that prevent magnetic film.As protective seam, can enumerate such as Cr layer, Cr alloy-layer, carbon-coating, hydrogenation carbon-coating, zirconia layer, silicon dioxide layer etc.These protective seams can form continuously by type sputter equipment in upright arrangement together with basalis or magnetic film etc.In addition, these protective seams can be individual layers, or can be comprise identical or different kind layer sandwich construction.

Can or replace described protective seam on described protective seam and form other protective seam.For example, can replace described protective seam, diluted in the solution that quaalkane oxosilane forms and be coated on Cr layer with the solvent of ethanol system by colloid silicon microparticle is scattered in, then having fired, form thus silicon dioxide (SiO ₂) layer.

As mentioned above, by using the HDD magnetic recording media that uses present embodiment related HDD to manufacture as substrate with glass substrate 80 for HDD, the having stable behavior of the magnetic head can make the High Rotation Speed of HDD time.

In addition, according to the HDD magnetic recording media of manufacturing with the related HDD glass substrate 80 of present embodiment, being used because circumferential TIR is suppressed to the HDD glass substrate 80 that the variation of little value and circumferential surface state is inhibited, is therefore the high-quality HDD magnetic recording media being inhibited of head collision.

In the present embodiment, with magnetic recording media, the rotating speed in the time being installed on hard disk drive is more than 7000rpm to the HDD preferably manufacturing with HDD glass substrate 80.

Accordingly, be rotated and be also difficult for occurring the high-quality HDD magnetic recording media because of the bad head collision causing of tracking of magnetic head even if realize with high speed more than 7000rpm.

In addition, in the present embodiment, grinding step and polishing process respectively carry out at twice, but are not limited to this, also can only carry out once.In addition, chemical enhanced operation is to carry out before the 2nd polishing process, but also can after the 2nd polishing process, carry out according to situation.

And, as the intensity countermeasure of falling, peripheral end face or interior all end faces beyond the first type surface of glass substrate can be strengthened, relax and process as the edge of the scar producing in glass substrate, can carry out HF dip treating to glass substrate.

The related HDD of present embodiment is not limited to the manufacture purposes of HDD magnetic recording media with glass substrate, for example, can also be used for the manufacture purposes of photomagneto disk, CD etc.

The technical characterictic that gathers present embodiment is as follows.

The related HDD of present embodiment comprises and glass substrate 80 be impregnated in to chemical enhanced treating fluid to glass substrate 80 is implemented to the chemical enhanced operation of chemical enhanced processing by the manufacture method of glass substrate, wherein, making the recruitment of the circumferential TIR of the glass substrate 80 of chemical enhanced operation front and back is below 0.5 μ m.

According to present embodiment, because the recruitment of the circumferential TIR of the glass substrate 80 before and after chemical enhanced operation is below 0.5 μ m, therefore, the deterioration of the circumferential TIR of the glass substrate 80 causing because of chemical enhanced processing is very restricted.Therefore, the circumferential TIR of the glass substrate 80 after chemical enhanced operation is suppressed to little value, and the variation of the circumferential surface state of glass substrate 80 is suppressed, thus being suppressed of head collision.

In the present embodiment, preferably making the recruitment of the circumferential TIR of the glass substrate 80 of chemical enhanced operation front and back is below 0.3 μ m.

According to present embodiment, because the deterioration of the circumferential TIR of the glass substrate 80 causing because of chemical enhanced processing is further limited.Therefore, further being suppressed of head collision.

Present embodiment, in chemical enhanced operation, changes the posture of the glass substrate 80 that impregnated in chemical enhanced treating fluid in chemical enhanced treating fluid, so that the recruitment of TIR is below 0.5 μ m.

According to present embodiment, do not change issuable in the situation of posture of glass substrate 80, be eliminated by the posture that changes glass substrate 80 by the different change of shape in surperficial each position of glass substrate 80.Therefore, the surface configuration of the glass substrate 80 before and after chemical enhanced processing changes equably, is below 0.5 μ m thereby can easily make TIR recruitment.

Present embodiment, in chemical enhanced operation, makes the temperature distribution homogenization of chemical enhanced treating fluid, so that the recruitment of TIR is below 0.5 μ m.

According to present embodiment, the temperature deviation of the chemical enhanced treating fluid of dipping glass substrate 80 is minimized.Therefore, the environment that surrounds glass substrate 80 becomes the same, and the surface configuration of the glass substrate 80 before and after chemical enhanced processing changes equably, is below 0.5 μ m thereby can easily make TIR recruitment.

Present embodiment, in chemical enhanced operation, stirs chemical enhanced treating fluid, so that the recruitment of TIR is below 0.5 μ m.

According to present embodiment, the concentration deviation of the chemical enhanced treating fluid of dipping glass substrate 80 is minimized.Therefore, the environment that surrounds glass substrate 80 becomes the same, and the surface configuration of the glass substrate 80 before and after chemical enhanced processing changes equably, is below 0.5 μ m thereby can easily make TIR recruitment.

Present embodiment is included in the polishing process (the 2nd polishing process) that after chemical enhanced operation, polishing is carried out in the surface of glass substrate 80.

According to present embodiment, the circumferential TIR of final glass substrate 80 further diminishes.Therefore, further being suppressed of head collision.

In the present embodiment, the circumferential TIR of glass substrate 80 refers in the time that the radius of glass substrate 80 is made as to R, leaves the circumferential TIR of the position of 0.75R from glass substrate 80 center.

According to present embodiment, the whole of the first type surface 81 that the peripheral end of the first type surface of glass substrate 80 81 and interior all ends are included or whole at the posting field that the peripheral end of the posting field of recording medium and interior all ends are included, the deterioration of circumferential TIR is very restricted, and occurring in wide scope of head collision is inhibited.

The related HDD of present embodiment utilizes the manufacture method of above-mentioned HDD glass substrate to make with glass substrate 80.

According to present embodiment, the high-quality glass substrate 80 for HDD that can obtain that variation that circumferential TIR is suppressed to little value and circumferential surface state is inhibited.

The related HDD of present embodiment forms recording layer with magnetic recording media and makes on the first type surface 81 of described HDD glass substrate 80.

According to present embodiment, due to the glass substrate 80 HDD for that the variation that uses circumferential TIR to be suppressed to little value and circumferential surface state is inhibited, therefore can obtain the high-quality HDD magnetic recording media being inhibited that head collides.

It is hard disk drive more than 7000rpm that the related HDD of present embodiment is preferably used to rotating speed with magnetic recording media.

According to present embodiment, be also difficult for occurring the high-quality HDD magnetic recording media because of the bad head collision causing of tracking of magnetic head even if can obtain with High Rotation Speed more than 7000rpm.

According to present embodiment, owing to manufacture method, the HDD glass substrate 80 of manufacturing by this manufacture method of the HDD the being inhibited glass substrate 80 bad head causing of the tracking on recording medium surface being collided because of magnetic head being provided and using the HDD magnetic recording media of this HDD glass substrate 80, therefore can a corresponding DFH mechanism, can contribute to nearest high density recording.

[embodiment]

Further describe the present invention by embodiment and comparative example below.But the present invention is not limited to this embodiment.

The manufacture > of glass substrate for <HDD

Manufacture HDD glass substrate according to the manufacturing process of Fig. 1.

[1. glass melting operation, molding procedure]

As glass raw material, use Tg is the alumina silicate glass of 480 DEG C, and the glass raw material of melting is carried out to impact briquetting, and producing external diameter is the discoideus glass substrate (blank) that 68mm, thickness are 0.93mm.

[2. heat treatment step]

Be that 70mm, thickness are that 2mm, material are aluminium oxide calibrator and glass substrate are alternately stacked by profile, and make its in the electric furnace of high temperature that is set to approximately 430 DEG C through 2 hours, make thus the warpage of glass substrate or internal stress reduce.

[3. the 1st grinding step]

Attrition process is carried out in two surfaces of glass substrate with twin grinder (HAMAI company system).As grinding condition, diamond pellet uses the diamond pellet of #1200 mesh, and load is made as to 100g/cm ²(9.81kPa), the rotating speed of upper flat plate is made as to 20rpm, the rotating speed of lower flat board is made as to 30rpm.

[4. getting core manufacturing procedure]

The core drill cylindraceous that use possesses skive forms at the central part of glass substrate the circular hole that diameter is 18mm.

[5. inside and outside footpath manufacturing procedure]

Carry out the processing of inside and outside footpath with the skive of drum type, the peripheral end face of glass substrate and interior all end faces are processed into external diameter 65mm and internal diameter 20mm.

[6. the 2nd grinding step]

Again use twin grinder (HAMAI company system) to carry out attrition process to two surfaces of glass substrate.As grinding condition, diamond pellet uses the diamond pellet of #1700 mesh, and load is made as to 100g/cm ²(9.81kPa), the rotating speed of upper flat plate is made as to 20rpm, the rotating speed of lower flat board is made as to 30rpm.

The total amount of grinding that makes the 1st and the 2nd grinding step is 0.1mm.Its result, the thickness of glass substrate becomes 0.83mm.

[7. end face polishing operation]

By stacked glass substrate 100, under this state, the peripheral end face with end face polishing machine to glass substrate and interior all end faces have carried out polishing.As the bristle of buffing machine, use the nylon fiber that diameter is 0.2mm.It is that the ceria of 3 μ m is as the mud of abrasive particle (polishing material) that polishing fluid use contains mean grain size.

[8. the 1st polishing process]

Upwards polishing is carried out in two surfaces of glass substrate in week with the Oscar buffing machine shown in Fig. 4 to Fig. 6.The circumferential TIR (the circumferential TIR before chemical enhanced operation) of the glass substrate obtaining is 0.7 μ m (with reference to table 1).The value of this TIR is the value at the circumferential TIR of the position of the center 0.75R apart from glass substrate in the time that the radius of glass substrate is made as to R.

[9. chemical enhanced operation]

In comparative example 1,2, as illustrated with reference to Fig. 8 (a), (b), (c), (d), carry out chemical enhanced processing (chemical enhanced processing in the past).The number of the glass substrate of stent support is made as to 50 (25 x2 row).

In embodiment 1,5, as illustrated with reference to Figure 11 (a), (b), (c), (d), (e), carry out chemical enhanced processing (one of concrete grammar of chemical enhanced processing involved in the present invention).The number of the glass substrate of stent support is made as to 50 (25 x2 row).

In embodiment 2,6, as illustrated with reference to Figure 13 (a), (b), (c), (d), carry out chemical enhanced processing (concrete grammar of chemical enhanced processing involved in the present invention two).The number of the glass substrate of stent support is made as to 50 (25 x2 row).

In embodiment 3,7, as illustrated with reference to Figure 13 (a), (b), (c), (d), carry out chemical enhanced processing (concrete grammar of chemical enhanced processing involved in the present invention three).The number of the glass substrate of stent support is made as to 50 (25 x2 row).But, in Figure 13 (b), only leave well heater 51, omit the multiple well heaters 52～54 that configure around liquid bath 50 processing.In addition, in the circular port of the central part of glass substrate 80, not configuration well heater 55 but configured the stirring rod without heating function.The rotating speed of stirring rod is made as to 60rpm.

In embodiment 4,8, as illustrated with reference to Figure 13 (a), (b), (c), (d), carry out chemical enhanced processing (two three combinations with it of the concrete grammar of chemical enhanced processing involved in the present invention).The number of the glass substrate of stent support is made as to 50 (25 × 2 row).But, in Figure 13 (b), used whole well heater 51～55.Well heater 55 is rotated as stirring rod.Rotating speed is made as to 60rpm.

[10. the 2nd polishing process]

Only in comparative example 2, embodiment 5～8, carry out the 2nd polishing process., with Twp-sided polishing machine (HAMAI company system), accurate polishing has further been carried out in two surfaces of glass substrate.As polishing condition, polishing pad uses the polishing pad of hardness for the isocyanurate foam system of Asker-C and 70 degree, the colloid silicon that it is 60nm using mean grain size that polishing fluid uses is scattered in water and becomes slimy solution as abrasive particle (polishing material), and the mixture ratio of water and abrasive particle is made as to 2: 8.In addition, load is made as to 90g/cm ²(8.83kPa), the rotating speed of upper flat plate is made as to 20rpm, the rotating speed of lower flat board is made as to 30rpm.

Total polished amount (comparative example 2, embodiment 5～8) of the polished amount of the 1st polishing process (comparative example 1, embodiment 1～4) or the 1st and the 2nd polishing process is all made as to 30 μ m.Its result, the thickness of final glass substrate becomes 0.8mm.

[11. matting]

Glass substrate is scrubbed.As cleaning fluid, use and with ultrapure water (DI water), potassium hydroxide (KOH) and NaOH (NaOH) have been carried out to dilution with the mixing of 1: 1 mass ratio and added non-ionic surfactant in order to improve cleansing power and the liquid that obtains.Providing by spraying of cleaning fluid undertaken.After scrubbing, in order to remove the surperficial cleaning fluid that residues in glass substrate, the matting that makes to wash by water is carried out 2 minutes in ultrasonic bath, and IPA matting is carried out 2 minutes in ultrasonic bath, last, utilizes IPA steam to make the dry tack free of glass substrate.

The manufacture > of magnetic recording media for <HDD

On the first type surface of obtained glass substrate, form magnetic film (recording layer), made thus magnetic recording media (vertical-type records form).The protective seam (thickness 5nm) that, stacks gradually the basalis (the about 100nm of thickness) being formed by Ni-Al, the recording layer (thickness 20nm) being formed by Co-Cr-Pt, formed by DLC (Diamond Like Carbon) from glass substrate side.100 magnetic recording medias in comparative example 1,2 and embodiment 1～8, are all made.

The evaluation > of magnetic recording media for <HDD

A suspension characteristic to the magnetic recording media of making is evaluated.That is, magnetic recording media is rotated with 7000rpm, this recording medium is used to the magnetic head of DFH mechanism, write head is to the bad number of times of the tracking on recording medium surface (the full posting field of each recording medium), and evaluates with following benchmark.Follow the tracks of bad number of times more, be judged to be more easily to occur head collision or read-write error.Result shown in table 1.

(metewand)

◎ ◎: following the tracks of bad number of times is 0 (impeccable optimum non-defective unit)

◎: following the tracks of bad number of times is 1 (good product)

Zero: following the tracks of bad number of times is 2～4 (non-defective units)

△: following the tracks of bad number of times is 5～9 (have qualitatively deviation, but not cannot use)

×: following the tracks of bad number of times is more than 10 (defective products)

In table 1, show in the lump the circumferential TIR of the glass substrate after recruitment, the chemical enhanced operation of circumferential TIR of the glass substrate before and after the circumferential TIR of the glass substrate before chemical enhanced operation, chemical enhanced operation and the circumferential TIR of final glass substrate (for the glass substrate after chemical enhanced operation, being the glass substrate after the 2nd polishing process) in comparative example 2 and embodiment 5～8 in comparative example 1 and embodiment 1～4.The value of these TIR is the value at the circumferential TIR of the position of the center 0.75R apart from glass substrate in the time that the radius of glass substrate is made as to R.

[table 1]

The investigation > of < result

In the comparative example 1,2 that has carried out chemical enhanced processing in the past, the recruitment of the circumferential TIR of the glass substrate before and after chemical enhanced operation exceedes 0.5 μ m, and (m), a suspension characteristic is poor for 0.7 μ.

In the embodiment 1,5 that has carried out one of concrete grammar of chemical enhanced processing involved in the present invention, the recruitment of the circumferential TIR of the glass substrate before and after chemical enhanced operation is that below 0.3 μ m, (m), a suspension characteristic is more good for 0.3 μ.

In two the embodiment 2,6 of concrete grammar that has carried out chemical enhanced processing involved in the present invention, the recruitment of the circumferential TIR of the glass substrate before and after chemical enhanced operation is that following (m), a suspension characteristic is more good for 0.3 μ for 0.3 μ m.

In three the embodiment 3,7 of concrete grammar that has carried out chemical enhanced processing involved in the present invention, the recruitment of the circumferential TIR of the glass substrate before and after chemical enhanced operation is that following (m), a suspension characteristic is more good for 0.5 μ for 0.5 μ m.

Carried out at the same time chemical enhanced processing involved in the present invention concrete grammar two and three embodiment 4,8 in, the recruitment of the circumferential TIR of the glass substrate before and after chemical enhanced operation is that below 0.3 μ m, (m), a suspension characteristic is more good for 0.2 μ.

The embodiment 5～8 that has carried out the 2nd polishing process after chemical enhanced operation is compared with the embodiment 1～4 that does not carry out the 2nd polishing process, and the circumferential TIR of the final glass substrate of embodiment 5～8 further diminishes, and a suspension characteristic is more good.

The application is willing to that taking the Japanese patent application laid of application on June 30th, 2011 2011-146229 is as basis, and its content comprises in this application.

In order to show the present invention, in foregoing, suitably and fully the present invention is described with reference to accompanying drawing by embodiment, still, should be realized that and just can easily change and/or improve above-mentioned embodiment as long as those skilled in the art.Thereby, the level of the interest field of the claim that the alter mode that those skilled in the art implement or mode of ameliorating are recorded so long as not disengaging claims, this alter mode or mode of ameliorating are just interpreted as being included in the interest field of this claim.

Utilizability in industry

The present invention has the utilizability in industry widely in the technical field with manufacture method, HDD glass substrate and the HDD magnetic recording media of glass substrate at HDD.

Claims

1. a manufacture method for glass substrate for HDD, is characterized in that comprising:

Chemical enhanced operation, impregnated in chemical enhanced treating fluid by glass substrate, to glass substrate is implemented to chemical enhanced processing, wherein,

Making the recruitment of the circumferential TIR of the glass substrate of chemical enhanced operation front and back is below 0.5 μ m.

2. the manufacture method of glass substrate for HDD according to claim 1, is characterized in that,

Making the recruitment of the circumferential TIR of the glass substrate of chemical enhanced operation front and back is below 0.3 μ m.

3. the manufacture method of glass substrate for HDD according to claim 1, is characterized in that,

In chemical enhanced operation, change the posture of the glass substrate that impregnated in chemical enhanced treating fluid in chemical enhanced treating fluid, so that the recruitment of TIR is below 0.5 μ m.

4. the manufacture method of glass substrate for HDD according to claim 1, is characterized in that,

In chemical enhanced operation, make the temperature distribution homogenization of chemical enhanced treating fluid, so that the recruitment of TIR is below 0.5 μ m.

5. the manufacture method of glass substrate for HDD according to claim 1, is characterized in that,

In chemical enhanced operation, stir chemical enhanced treating fluid, so that the recruitment of TIR is below 0.5 μ m.

6. the manufacture method with glass substrate according to the HDD described in any one in claim 1 to 5, is characterized in that comprising:

Polishing process, after chemical enhanced operation, carries out polishing to the surface of glass substrate.

7. the manufacture method with glass substrate according to the HDD described in any one in claim 1 to 6, is characterized in that,

The circumferential TIR of glass substrate refers to the circumferential TIR that leaves the position of 0.75R in the time that the radius of glass substrate is made as to R from glass substrate center.

8. a HDD glass substrate, is characterized in that,

Utilize the manufacture method of the HDD glass substrate described in any one in claim 1 to 7 to make.

9. a HDD magnetic recording media, is characterized in that,

On first type surface at HDD claimed in claim 8 with glass substrate, form recording layer and make.

10. HDD magnetic recording media according to claim 9, is characterized in that,

Being used to rotating speed is hard disk drive more than 7000rpm.