JP2001167430A - Substrate for magnetic disk and its manufacturing method - Google Patents
Substrate for magnetic disk and its manufacturing methodInfo
- Publication number
- JP2001167430A JP2001167430A JP34941299A JP34941299A JP2001167430A JP 2001167430 A JP2001167430 A JP 2001167430A JP 34941299 A JP34941299 A JP 34941299A JP 34941299 A JP34941299 A JP 34941299A JP 2001167430 A JP2001167430 A JP 2001167430A
- Authority
- JP
- Japan
- Prior art keywords
- glass substrate
- polishing
- magnetic disk
- abrasive
- less
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Landscapes
- Magnetic Record Carriers (AREA)
- Manufacturing Of Magnetic Record Carriers (AREA)
- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
- Surface Treatment Of Glass (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、磁気ディスク装置
に用いられる磁気ディスク用ガラス基板、特にＧＭＲへ
ッド等を用いて高密度記録を行うのに適した磁気ディス
ク用ガラス基板およびその製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass substrate for a magnetic disk used in a magnetic disk drive, and more particularly to a glass substrate for a magnetic disk suitable for performing high-density recording using a GMR head or the like, and a method of manufacturing the same. About.
【０００２】[0002]
【従来の技術】近年、コンピュータの記憶装置として用
いられている磁気ディスク装置においては、その記録密
度を高めるために、磁気ヘッドの浮上高さを小さくする
ことが行われている。磁気ディスク装置において、磁気
へッドの浮上高さが小さくなっても、信号の正確な記録
・再生を維持するためには、浮上高さが小さくなったこ
とに応じて磁気ディスク表面がより平滑であり、且つ平
面性が優れることが必要条件となっている。2. Description of the Related Art In recent years, in a magnetic disk device used as a storage device of a computer, the flying height of a magnetic head has been reduced in order to increase the recording density. In a magnetic disk drive, even if the flying height of the magnetic head becomes small, the surface of the magnetic disk becomes smoother in accordance with the reduced flying height in order to maintain accurate recording and reproduction of signals. It is a necessary condition that the flatness is excellent.
【０００３】従来、磁気ディスク用ガラス基板の製造に
は、例えば、プレス成形や板成形でまず円盤状とし、次
にラッピング等の粗研削を行って基板の板厚を規定の範
囲にし、次に内周の下穴を形成しドーナツ円盤状とし、
さらに内外周側面部を内外周形状加工機等で加工を行
い、内周と外周を規定寸法にし、その後ドーナツ円盤の
表裏面を両面研磨機等にポリッシングし、さらに鏡面仕
上げをし、洗浄を行って磁気ディスク用ガラス基板に仕
上げるという工程が用いられている。なお母材のガラス
が化学強化を要するガラスの場合には、両面の研磨を行
った後に溶融塩中に浸漬してイオン交換を行う化学強化
処理を行ってから、洗浄して磁気ディスク用ガラス基板
に仕上げられている。Conventionally, in the production of a glass substrate for a magnetic disk, for example, a disk shape is first formed by press molding or plate forming, and then rough grinding such as lapping is performed to bring the substrate thickness to a specified range. Form a prepared hole in the inner circumference and make it a donut disk shape,
Furthermore, the inner and outer peripheral side parts are processed with an inner and outer peripheral shape processing machine etc., the inner and outer circumferences are set to specified dimensions, then the front and back surfaces of the donut disk are polished by a double-side polishing machine, etc., and further mirror-finished and washed To finish the glass substrate for magnetic disks. If the glass of the base material is a glass that requires chemical strengthening, the glass substrate for the magnetic disk is subjected to chemical strengthening treatment in which both sides are polished, then immersed in a molten salt to perform ion exchange, and then washed. It is finished.
【０００４】しかしながら、磁気ディスク用ガラス基板
の表面性をより良好にして、磁気ディスク装置において
磁気ヘッドの浮上高さが小さくなることに対応するため
に、最終ポリツシング研磨として、例えば研磨材に酸化
セリウムを用い、研磨パッドとしてスエードパッドを用
い、さらに例えば面圧１００ｇ／ｃｍ2 、研磨時間１０
分の条件で行ってみても、極微小の突起が発生して表面
粗さの劣化が生じ、しかも平坦性の低下も生じてしまう
という問題があった。However, in order to improve the surface properties of the glass substrate for the magnetic disk and to cope with the decrease in the flying height of the magnetic head in the magnetic disk device, for example, cerium oxide is added to the polishing material as final polishing. And a suede pad as a polishing pad. Further, for example, a surface pressure of 100 g / cm 2 and a polishing time of 10
Even under the conditions of minute, there is a problem that extremely minute projections are generated, the surface roughness is deteriorated, and the flatness is also deteriorated.
【０００５】しかも、母材のガラスを溶融塩に浸漬して
イオン交換する化学強化処理（例えば特公平３−５２１
３０号公報）を行った場合に、使用した溶融液中の不純
物や分解物により、ガラス基板が侵食を受けるなどし
て、表面の平滑性が失われて表面性が劣化するという問
題があつた。In addition, chemical strengthening treatment (for example, Japanese Patent Publication No. 3-521) in which glass of a base material is ion-exchanged by immersing it in a molten salt.
No. 30), there is a problem that the glass substrate is eroded by impurities or decomposed products in the melt used, the surface smoothness is lost, and the surface property is deteriorated. .
【０００６】[0006]
【発明が解決しようとする課題】本発明は上記の問題点
を解決するためになされたものであって、基板表面に対
して表面粗さを極微小の突起に至るまで低減し平坦性を
確保して、磁気ディスク装置の磁気ヘッドの浮上高さを
小さくして高密度化を行うことに対応できる磁気ディス
ク用ガラス基板およびその製造方法を提供するものであ
る。SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and has reduced the surface roughness of the substrate surface to very small protrusions to ensure flatness. It is another object of the present invention to provide a glass substrate for a magnetic disk and a method of manufacturing the same, which can cope with high density by reducing the flying height of a magnetic head of a magnetic disk device.
【０００７】[0007]
【課題を解決するための手段】本発明は、原子間力顕微
鏡（以下ＡＦＭと略称する）を用いることによって初め
て観察が可能になった、磁気ディスク用ガラス基板表面
に生ずる極微小突起と、この基板を用いた磁気ディスク
の特性との関係を、本発明者が詳細に調べた結果、以下
に述べる知見を得たことに基づくものである。SUMMARY OF THE INVENTION The present invention relates to a microscopic projection formed on the surface of a glass substrate for a magnetic disk, which can be observed for the first time by using an atomic force microscope (AFM). This is based on the following findings as a result of the inventor's detailed investigation of the relationship with the characteristics of a magnetic disk using a substrate.
【０００８】ガラス基板に存在する突起は、ＡＦＭを用
いることで観察が可能になる程度に極微少であっても、
化学強化処理によってこの突起が強調されること、そし
てガラス基板にスパッタリングを行って磁性膜を形成し
て磁気ディスクを作製した場合には、これらの突起によ
り、磁気ディスク面の磁性膜の突起が生じることがわか
った。さらに磁気ディスク装置にこの磁気ディスク基板
を実装して回転させてヘッドで読み書きした場合には、
この突起がへッドクラッシュの原因となり得ることがわ
かった。即ち、上記ガラス基板の極微少突起によって、
へッドクラッシュ率の増加、そして製造歩留の低下が生
じることがわかった。また、最終研磨工程で研磨材とし
て用いる酸化セリウムを含む希土類酸化物によって、基
板表面の極微小突起に差異が生じること、特にＣｅＯ2
の含有量とその粒径の相違により、極微小突起の発生に
差異が生じることがわかった。さらにこの極微小突起の
程度（大きさと数）の評価には、下記の二乗平均粗さＲ
ＭＳが適切であることがわかった。そして本発明者は、
ＲＭＳを評価の尺度として鋭意研究を行い、この極微小
突起を小さくするための研磨方法を見出すことができた
ものである。[0008] Even if the projections existing on the glass substrate are so small that they can be observed by using the AFM,
These protrusions are emphasized by the chemical strengthening process, and when a magnetic disk is formed by sputtering a glass substrate to form a magnetic film, these protrusions cause protrusions of the magnetic film on the surface of the magnetic disk. I understand. Further, when this magnetic disk substrate is mounted on a magnetic disk device, rotated, and read and written by a head,
It has been found that this projection can cause a head crash. That is, by the very small projections of the glass substrate,
It was found that an increase in the head crash rate and a decrease in the production yield occurred. In addition, a difference occurs in the microscopic projections on the substrate surface due to the rare earth oxide containing cerium oxide used as the polishing material in the final polishing step, in particular, CeO 2.
It was found that the difference in the content of and the particle size caused a difference in the generation of the microscopic projections. Further, the evaluation of the degree (size and number) of the microscopic projections is based on the following mean square roughness R:
MS turned out to be appropriate. And the inventor
The present inventors have conducted intensive studies using RMS as a scale of evaluation, and have found a polishing method for reducing such microscopic projections.
【０００９】本発明は、ガラス基板表面の算術平均粗さ
Ｒａが０．５ｎｍ以下、二乗平均粗さＲＭＳが０．６ｎ
ｍ以下、微小うねりＷA が０．５ｎｍ以下であることを
特徴とする磁気ディスク用ガラス基板である。According to the present invention, the arithmetic mean roughness Ra of the glass substrate surface is 0.5 nm or less, and the root mean square roughness RMS is 0.6 n.
m or less, a glass substrate for a magnetic disk, wherein the micro-waviness W A is 0.5nm or less.
【００１０】ここに、算術平均粗さＲａはＪＩＳのＢ０
６０１に規定されたものであって、粗さ曲線の絶対値の
基準長さでの平均値、即ち、Here, the arithmetic average roughness Ra is JIS B0
601, wherein the average value of the absolute value of the roughness curve at the reference length, that is,
【数１】 である。ここにｆ（ｘ）は粗さ曲線、Ｌは基準長さであ
る。(Equation 1) It is. Here, f (x) is a roughness curve, and L is a reference length.
【００１１】また、二乗平均粗さＲＭＳは、粗さ曲線
（表面を測定した測定曲線とその平均を示す平均線との
偏差）の二乗を平均した値の平方根、即ち、The root-mean-square roughness RMS is a square root of a value obtained by averaging the squares of a roughness curve (a deviation between a measurement curve obtained by measuring a surface and an average line indicating the average), that is,
【数２】 である。ここにｆ（ｘ）は粗さ曲線、Ｌは基準長さであ
る。(Equation 2) It is. Here, f (x) is a roughness curve, and L is a reference length.
【００１２】さらに微小うねりＷA は、ＪＩＳのＢ０６
１０に規定されたろ波中心線うねりＷCAであって、低域
カットオフ値１．４ｍｍ、高域カットオフ値０．２５ｍ
ｍとしたものである。[0012] In addition micro-waviness W A is, B06 of JIS
10 to a prescribed filtered centerline waviness W CA, low cut-off value 1.4 mm, the high frequency cut-off value 0.25m
m.
【００１３】本発明において、ガラス基板表面の算術平
均粗さＲａは、より好ましくは０．４ｎｍ以下である。
またガラス基板表面の二乗平均粗さＲＭＳは、より好ま
しくは０．４ｎｍ以下である。そしてガラス基板表面の
微小うねりＷA はより好ましくは０．４ｎｍ以下であ
る。In the present invention, the arithmetic average roughness Ra of the glass substrate surface is more preferably 0.4 nm or less.
The root mean square roughness RMS of the glass substrate surface is more preferably 0.4 nm or less. The waviness W A of the glass substrate surface is more preferably at most 0.4 nm.
【００１４】磁気ディスク用ガラス基板表面の算術平均
粗さＲａを上記の範囲にするとともに、二乗平均粗さＲ
ＭＳを上記の範囲にし、さらに微小うねりＷA を上記の
範囲にすることにより、この基板を用いた磁気ディスク
のヘッドクラッシュ率を大幅に低減することができる。The arithmetic mean roughness Ra of the surface of the glass substrate for a magnetic disk is set in the above range, and the mean square roughness R
The MS within the above range, further by the micro-waviness W A within the above range, the head crash rate of the magnetic disk using the substrate can be significantly reduced.
【００１５】本発明の磁気ディスク用ガラス基板に用い
られるガラス母材としては、アルミノシリケートガラス
のほか、ソーダライムガラス、ソーダアルミノシリケー
トガラス、アルミノボロシリケートガラス、ボロシリケ
ートガラス、石英ガラス、結晶化ガラスなどが挙げられ
る。The glass base material used for the glass substrate for a magnetic disk of the present invention includes, in addition to aluminosilicate glass, soda lime glass, sodaaluminosilicate glass, aluminoborosilicate glass, borosilicate glass, quartz glass, crystallized glass And the like.
【００１６】また本発明の磁気ディスク用ガラス基板の
製造方法は、ガラス素材をガラス基板に成形する工程
と、前記ガラス基板の表面を研磨加工する工程と、表面
研磨された前記基板を溶融塩に浸漬してイオン交換によ
る化学強化処理を行う工程とを含む磁気ディスク用ガラ
ス基板の製造方法において、前記研磨加工する工程に用
いる研磨材中に酸化セリウムを６０質量％以上含有させ
て研磨を行う工程を有するものである。Further, in the method of manufacturing a glass substrate for a magnetic disk according to the present invention, a step of forming a glass material into a glass substrate, a step of polishing the surface of the glass substrate, and a step of converting the surface-polished substrate to a molten salt A method of manufacturing a glass substrate for a magnetic disk, comprising: immersing and performing a chemical strengthening treatment by ion exchange, wherein the polishing is performed by incorporating cerium oxide in the polishing material used for the polishing process in an amount of 60% by mass or more. It has.
【００１７】研磨加工する工程に用いる研磨材中に酸化
セリウムを６０質量％以上含有させて研磨を行うことに
より、適切な研磨レートでガラス基板平面の算術平均粗
さＲａを０．５ｎｍ以下、二乗平均粗さＲＭＳを０．６
ｎｍ以下、微小うねりＷA を０．５ｎｍ以下にすること
ができる。By polishing with cerium oxide contained in the polishing material used in the polishing step in an amount of 60% by mass or more, the arithmetic average roughness Ra of the glass substrate plane at an appropriate polishing rate is 0.5 nm or less, squared. Average roughness RMS is 0.6
nm or less, the micro-waviness W A can be reduced to 0.5nm or less.
【００１８】本発明において、研磨加工する工程に用い
る研磨材中に含まれる酸化セリウムは６０質量％以上、
８０質量％以下であることがより好ましく、６０質量％
以上７０質量％以下であることがさらに好ましい。In the present invention, the cerium oxide contained in the abrasive used in the polishing step is 60% by mass or more,
It is more preferably 80% by mass or less, and 60% by mass.
More preferably, it is at least 70% by mass.
【００１９】そして本発明においては、前記研磨剤とし
て、平均粒径Ｄ50が０．５μｍ以上１．５μｍ以下の酸
化セリウムを含むものを用い、研磨レートを０．１μｍ
／分以上０．５μｍ／分以下で研磨を行うことが好まし
い。In the present invention, an abrasive containing cerium oxide having an average particle diameter D 50 of 0.5 μm or more and 1.5 μm or less is used, and the polishing rate is 0.1 μm.
The polishing is preferably performed at a rate of not less than 0.5 μm / min.
【００２０】ここに研磨レートは単位時間（分）あたり
の研磨量（μｍ）であって、０．１μｍ／分以上０．５
μｍ／分以下で研磨を行うことによって、上記所定の数
値範囲の表面粗さと微小うねりを有する、良好な表面を
得ることができる。研磨レートが大きくなるとこのよう
な良好な表面を得ることが次第に困難になり、また、研
磨レートが低くなると、上記所定の数値範囲の表面粗さ
と微小うねりを有する表面を得るのに時間がかかるので
好ましくないだけでなく、長時間の研磨中にキズなどを
発生させてしまう割合が高まってしまう。Here, the polishing rate is a polishing amount (μm) per unit time (minute), and is 0.1 μm / min or more and 0.5 μm or more.
By polishing at μm / min or less, it is possible to obtain a good surface having surface roughness and minute waviness in the above-mentioned predetermined numerical range. As the polishing rate increases, it becomes increasingly difficult to obtain such a good surface, and when the polishing rate decreases, it takes time to obtain a surface having the surface roughness and minute waviness in the above predetermined numerical range. Not only is it undesirable, but the rate of occurrence of scratches and the like during long-time polishing increases.
【００２１】また本発明の磁気ディスク用ガラス基板の
製造方法は、ガラス素材をガラス基板に成形する工程
と、前記ガラス基板の表面を研磨加工する工程と、表面
研磨された前記基板を溶融塩に浸漬してイオン交換によ
る化学強化処理を行う工程とを含む磁気ディスク用ガラ
ス基板の製造方法において、前記研磨加工する工程が研
磨材を含む溶液を用いて研磨する工程と、研磨材を含ま
ない溶液を用いて研磨する工程とを含むものであっても
よい。The method of manufacturing a glass substrate for a magnetic disk according to the present invention comprises the steps of forming a glass material into a glass substrate, polishing the surface of the glass substrate, and converting the surface-polished substrate into a molten salt. A method of manufacturing a glass substrate for a magnetic disk, comprising: immersing and performing a chemical strengthening treatment by ion exchange, wherein the polishing step is a step of polishing using a solution containing an abrasive, and a solution containing no abrasive. And a step of polishing by using.
【００２２】研磨加工する工程が研磨材を含む溶液を用
いて研磨する工程に加えて、研磨材を含まない溶液を用
いて研磨する工程とを有することにより、前記ガラス基
板の極微小突起を低減し、表面性の向上、特にＲＭＳを
低減することができる。そしてガラス基板平面の算術平
均粗さＲａを０．５ｎｍ以下、二乗平均粗さＲＭＳを
０．６ｎｍ以下、微小うねりＷA を０．５ｎｍ以下にす
ることができる。[0022] In addition to the step of polishing using a solution containing an abrasive, the step of polishing includes the step of polishing using a solution containing no abrasive. In addition, it is possible to improve the surface properties, in particular, to reduce the RMS. The following 0.5nm arithmetic mean roughness Ra of the glass substrate plane, the root mean square roughness RMS 0.6 nm or less, it is possible to fine waviness W A to 0.5nm or less.
【００２３】この場合に、前記研磨材を含む液が研磨材
中に酸化セリウムを６０質量％以上含有した懸濁液であ
り、前記研磨材を含まない溶液が水または水に界面活性
剤を添加した溶液であることが好ましい。さらに好まし
くは、前記研磨材を含まない溶液が水に界面活性剤を添
加した溶液である。In this case, the liquid containing the abrasive is a suspension containing 60% by mass or more of cerium oxide in the abrasive, and the solution containing no abrasive is water or a surfactant added to water. It is preferable that the solution is prepared. More preferably, the solution containing no abrasive is a solution obtained by adding a surfactant to water.
【００２４】そして、前記界面活性剤の濃度は０．５質
量％以上３０質量％未満であることが好ましい。界面活
性剤の濃度が３０質量％以上であると、ガラス基板とス
エードウレタンパッドとの摩擦力が低下するので、研磨
工程の生産性が低下し、界面活性剤による研磨の効果を
得ることが難しくなる。界面活性剤の濃度が０．５質量
％未満であると、界面活性剤を添加した効果、即ちガラ
ス基板の表面にキズを生じることなく、基板表面を仕上
げる効果が低下する。界面活性剤はｐＨ８．４〜９．４
のものを好ましく用いることができる。また界面活性剤
を添加した液は循環して用いることができる。The concentration of the surfactant is preferably 0.5% by mass or more and less than 30% by mass. When the concentration of the surfactant is 30% by mass or more, the frictional force between the glass substrate and the suede urethane pad is reduced, so that the productivity of the polishing step is reduced, and it is difficult to obtain the effect of polishing by the surfactant. Become. When the concentration of the surfactant is less than 0.5% by mass, the effect of adding the surfactant, that is, the effect of finishing the substrate surface without causing scratches on the surface of the glass substrate is reduced. The surfactant has a pH of 8.4 to 9.4.
Can be preferably used. The liquid to which the surfactant has been added can be circulated and used.
【００２５】本発明の磁気ディスク用ガラス基板の製造
方法は、化学強化処理を行って用いる磁気ディスク用ガ
ラス基板に用いることができる。このため、本発明の磁
気ディスク用ガラス基板の製造方法は、化学強化後のガ
ラス基板表面に対して、算術平均粗さＲａを０．５ｎｍ
以下、二乗平均粗さＲＭＳを０．６ｎｍ以下、微小うね
りＷA を０．５ｎｍ以下にするものであることが好まし
い。そして化学強化処理後のガラス基板表面の算術平均
粗さＲａは、より好ましくは０．４ｎｍ以下である。ま
た化学強化処理後のガラス基板表面の二乗平均粗さＲＭ
Ｓは、より好ましくは０．４以下である。そして化学強
化処理後のガラス基板表面の微小うねりＷA はより好ま
しくは０．４ｎｍ以下である。The method for producing a glass substrate for a magnetic disk of the present invention can be applied to a glass substrate for a magnetic disk used after being subjected to a chemical strengthening treatment. For this reason, the method for manufacturing a glass substrate for a magnetic disk of the present invention provides the glass substrate surface after the chemical strengthening with an arithmetic average roughness Ra of 0.5 nm.
Or less, 0.6nm a root mean square roughness RMS, it is preferable to micro-waviness W A is intended to 0.5nm or less. The arithmetic average roughness Ra of the glass substrate surface after the chemical strengthening treatment is more preferably 0.4 nm or less. The root mean square roughness RM of the glass substrate surface after the chemical strengthening treatment
S is more preferably 0.4 or less. The waviness W A of the glass substrate surface after the chemical strengthening treatment is more preferably at most 0.4 nm.
【００２６】本発明で使用する研磨機は、その構造や使
用するパッドなど、特に制限されるものではない。そし
て両面研磨機であれば効率的に処理を行うことができる
ので好ましく用いることができる。また、研磨材の含有
成分として酸化セリウム以外については、特に限定はな
い。The polishing machine used in the present invention is not particularly limited, such as its structure and the pad used. If a double-side polishing machine can be used efficiently, it can be preferably used. There is no particular limitation on components other than cerium oxide as a component of the abrasive.
【００２７】本発明の磁気ディスク用ガラス基板の母材
のガラス材は、ガラス基板として必要な平坦性、平滑
性、高硬度、耐蝕性および耐熱性が得られるものであれ
ば、特に制限されるものではない。The glass material of the base material of the glass substrate for a magnetic disk of the present invention is not particularly limited as long as it can provide the flatness, smoothness, high hardness, corrosion resistance and heat resistance required for the glass substrate. Not something.
【００２８】[0028]
【発明の実施の形態】本発明の実施の形態を、実施例を
示して具体的に説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described with reference to examples.
【００２９】（実施例１）化学強化処理によって強化さ
れるガラス母材として、アルミノシリケートガラス母材
を選び、この母材を直径６７ｍｍ、厚さ１．４ｍｍにプ
レスして素材を得た。この素材に対し、両面研磨機を用
いて表裏面のラッピング加工を数段に分けて行った。即
ち、内周の下穴をあけ、内外周加工機を用いて、内周面
および外周面側面に所定の面取り加工を行った。引き続
いて、基板の表面に対し、数段のポリッシングによって
鏡面仕上げを行った。さらにＧＭＲヘッド走行に適する
平滑度を得るために、最終研磨工程を実施した。最終研
磨工程は研磨材として酸化セリウムを含む希土類酸化
物、特にＣｅＯ2 の含有量を６０質量％としたもの、ま
た、平均粒径Ｄ50が０．５〜１．５μｍのものにてポリ
ッシャーにスエードウレタンパッドを用いてポリッシユ
を行い、表面粗さがＲａ０．３３ｎｍ、ＲＭＳ０．４０
ｎｍ、微小うねりＷA 0.4 ｎｍの基板を得た。Example 1 An aluminosilicate glass base material was selected as a glass base material to be strengthened by the chemical strengthening treatment, and this base material was pressed to a diameter of 67 mm and a thickness of 1.4 mm to obtain a material. This material was subjected to lapping on the front and back surfaces in several stages using a double-side polishing machine. That is, a prepared hole was formed on the inner periphery, and a predetermined chamfering process was performed on the inner peripheral surface and the outer peripheral surface side surface using an inner and outer peripheral processing machine. Subsequently, the surface of the substrate was mirror-finished by polishing in several stages. Further, a final polishing step was performed to obtain a smoothness suitable for running the GMR head. In the final polishing step, the content of a rare earth oxide containing cerium oxide as a polishing material, in particular, CeO 2 is adjusted to 60% by mass, and the average particle diameter D 50 is 0.5 to 1.5 μm. Polishing is performed using a suede urethane pad, and the surface roughness is Ra 0.33 nm and RMS 0.40.
nm, a substrate having a fine undulation W A 0.4 nm was obtained.
【００３０】ここに表面粗さの測定値、ＲａおよびＲＭ
Ｓは、原子間力顕微鏡（デジタルインスツルメンツ
（株）社製；商品名ＮａｎｏＳｃｏｐｅ：以下ＡＦＭと
記載する）で測定し、微小うねりＷA の測定は、３次元
表面構造解析顕微鏡（ＺＹＧＯ社製；商品名ＮＥＷＶＩ
ＥＷ２００：以下ＺＹＧＯと記載する）によって行っ
た。以下実施例２、比較例１〜６における測定について
も、同じ測定手段によって行った。Here, the measured values of surface roughness, Ra and RM
S is an atomic force microscope (Digital Instruments Co., Ltd .; trade name NanoScope: hereinafter referred to as AFM) is measured, the measurement of minute waviness W A is 3-dimensional surface structure analysis microscope (ZYGO Corporation; trade Name NEWVI
EW200: hereinafter referred to as ZYGO). Hereinafter, the measurements in Example 2 and Comparative Examples 1 to 6 were also performed by the same measuring means.
【００３１】（実施例２）最終研磨工程にて研磨材とし
て、酸化セリウムを含む希士類酸化物、特にＣｅＯ2 の
含有量を９０質量％としたもの、また平均粒径Ｄ50を
０．５〜１．５μｍｍのもの）を用い、ポリッシャーに
スエードウレタンパッドを用いてポリッシユを行い、表
面粗さＲａが０．２８ｎｍ．ＲＭＳが０．３４ｎｍ、微
小うねりＷAが０．４ｎｍの基板を得た。(Example 2) As a polishing material in the final polishing step, a rare earth oxide containing cerium oxide, particularly, a content of CeO 2 was set to 90% by mass, and an average particle diameter D 50 was set to 0.1%. And a polisher using a suede urethane pad, and the surface roughness Ra is 0.28 nm. A substrate having an RMS of 0.34 nm and a fine waviness WA of 0.4 nm was obtained.
【００３２】（比較例１）最終研磨工程にて研磨材とし
て、酸化セリウムを含む希土類酸化物、特にＣｅ０２の
含有量を１０質量％としたもの、また平均粒径Ｄ50が
１．６〜２．５μｍのものにてポリッシャーにスエード
ウレタンパッドを用いてポリツシュを行い、表面粗さＲ
ａ０．５２ｎｍ．，ＲＭＳ０．６２ｎｍ、微小うねりＷ
A が０．５ｎｍの基板を得た。[0032] as an abrasive in (Comparative Example 1) final polishing step, rare earth oxides including cerium oxide, in particular the content of Ce02 ones were 10 mass%, the average particle diameter D 50 of from 1.6 to 2 Polishing is performed using a suede urethane pad on a polisher with a surface roughness R of 0.5 μm.
a 0.52 nm. , RMS 0.62 nm, small undulation W
A substrate having A of 0.5 nm was obtained.
【００３３】（比較例２）最終研磨工程にて研磨材とし
て、酸化セリウムを含む希土類酸化物、特にＣｅＯ2 の
含有量を１０質量％としたもの、また平均粒径Ｄ50が
０．５〜１．５μｍのものにてポリッシャーにスエード
ウレタンパッドを用いてポリッシュを行い、表面粗さが
Ｒａ０．３１ｎｍ、ＲＭＳ０．３７ｎｍ、微小うねりＷ
A ０．５ｎｍを得た。(Comparative Example 2) As a polishing material in the final polishing step, a rare earth oxide containing cerium oxide, in particular, a content of CeO 2 was set to 10% by mass, and an average particle diameter D 50 was 0.5 to 50 %. Polishing is performed using a suede urethane pad with a 1.5 μm polisher, and the surface roughness is Ra 0.31 nm, RMS 0.37 nm, and fine undulation W
A 0.5 nm was obtained.
【００３４】（比較例３）最終研磨工程にて研磨材とし
て、酸化セリウムを含む希上類酸化物、特にＣｅＯ2 の
含有量を５０質量％としたものまた、平均粒径Ｄ50が1.
6 〜2.5 μｍのものにてポリッシャーにスエードウレタ
ンパッドを用いてポリッシュを行い、表面組さＲａ０．
５５ｎｍ、ＲＭＳ０．６６ｎｍ、微小うねりＷA ０．５
ｎｍを得た。(Comparative Example 3) As a polishing material in the final polishing step, a rare-earth oxide containing cerium oxide, in particular, the content of CeO 2 was set to 50% by mass, and the average particle diameter D 50 was 1.
Polishing is performed using a suede urethane pad with a polisher of 6 to 2.5 μm, and the surface assembly Ra0.
55 nm, RMS 0.66 nm, micro undulation W A 0.5
nm was obtained.
【００３５】（比較例４）最終研磨工程にて研磨材とし
て、酸化セリウムを含む希土類酸化物、特にＣｅＯ2 の
含有量を５０質量％としたもの、また平均粒径Ｄ50が
０．５〜１．５μｍのものにてポリッシャーにスエード
ウレタンパッドを用いてポリッシュを行い、表面粗さＲ
ａ０．５２ｎｍ．ＲＭＳ０．６３ｎｍ、微小うねりＷA
０．５ｎｍを得た。(Comparative Example 4) A rare earth oxide containing cerium oxide, in particular, a CeO 2 content of 50% by mass as an abrasive in the final polishing step, and an average particle diameter D 50 of 0.5 to 1 Polished using a suede urethane pad with a polisher with a surface roughness R
a 0.52 nm. RMS 0.63nm, micro undulation W A
0.5 nm was obtained.
【００３６】（比較例５）最終研磨工程にて研磨材とし
て、酸化セリウムを含む希土類酸化物、特にＣｅＯ2 の
含有量を６０質量％としたものまた、平均粒径Ｄ50が
１．６〜２．６μｍのものにてポリツシャーにスエード
ウレタンバッドを用いてポリッシュを行い、表面粗さＲ
ａ０．５８ｎｍ、ＲＭＳ０．７０ｎｍ、微小うねりＷA
０．５ｎｍを得た。[0036] As the abrasive at (Comparative Example 5) final polishing step, rare earth oxides including cerium oxide, in particular those with the content of CeO 2 and 60 wt%, average particle diameter D 50 of 1.6 Polishing is performed using a suede urethane pad on a polisher with a 2.6 μm surface, and the surface roughness R
a 0.58 nm, RMS 0.70 nm, micro undulation W A
0.5 nm was obtained.
【００３７】（比較例６）最終研磨工程にて研磨材とし
て、酸化セリウムを含む希土類酸化物、特にＣｅＯ2 の
含有量を９０質量％としたもの、また平均粒径Ｄ50が
１．６〜２．５μｍのものにてポリッシャーにスエード
ウレタンパッドを用いてポリッシュを行い、表面粗さＲ
ａ０．６０ｎｍ．ＲＭＳ０．７２ｎｍ、微小うねりＷA
０．４５ｎｍを得た。Comparative Example 6 A rare earth oxide containing cerium oxide, in particular, a CeO 2 content of 90% by mass was used as an abrasive in the final polishing step, and the average particle size D 50 was 1.6 to 1.5%. Polishing is performed using a suede urethane pad on a polisher with a surface roughness R
a 0.60 nm. RMS 0.72nm, micro undulation W A
0.45 nm was obtained.
【００３８】以上の実施例１〜２と比較例１〜６の結果
を研磨条件とともに表１にまとめた。また最終研磨時の
研磨レート（＝研磨量／研磨）時間の比較についても表
１に合わせて示した。Table 1 summarizes the results of Examples 1 and 2 and Comparative Examples 1 to 6 together with the polishing conditions. Table 1 also shows a comparison of the polishing rate (= polishing amount / polishing) time in the final polishing.
【００３９】[0039]
【表１】 [Table 1]
【００４０】表１から明らかなように、最終研磨工程で
使用する研磨材として、酸化セリウムＣｅＯ2 の含有量
が６０質量％以上で、平均粒径Ｄ50が０．５〜１．５μ
ｍ前後の研磨剤で行った結果が、ガラス基板の表面の状
態が良好であり、また研磨レートも良好てであった。こ
れに対し、酸化セリウムＣｅＯ2 の平均粒径Ｄ50が０．
５〜１．５μｍであっても、その含有量が１０質量％の
研磨材で行った場合は、研磨レートの点で不満足な結果
となった。研磨レートの低い場合はその生産性が劣ると
ともに、長時間の研磨により、研磨歩留まりについても
低下する可能性が大きい。As is clear from Table 1, as the abrasive used in the final polishing step, the content of cerium oxide CeO 2 is 60% by mass or more, and the average particle size D 50 is 0.5 to 1.5 μm.
As a result of using a polishing agent of about m, the state of the surface of the glass substrate was good, and the polishing rate was also good. On the other hand, cerium oxide CeO 2 has an average particle size D 50 of 0.1.
Even when the thickness is 5 to 1.5 μm, when the polishing is performed using an abrasive having a content of 10% by mass, the polishing rate is unsatisfactory. When the polishing rate is low, the productivity is poor, and the polishing yield is also likely to decrease due to long-time polishing.
【００４１】（実施例３〜１７）実施例１．２と同様
に、アルミノシリケートガラスを母材とし用い、直径６
７ｍｍ、厚さ１．４ｍｍにブレス加工した素材を、まず
両面研磨機を用いて＃４００のアルミナ砥粒で表裏面の
ラッピング加工を行った。(Examples 3 to 17) As in Example 1.2, aluminosilicate glass was used as a base material,
First, the front and back surfaces of a material which had been processed to a thickness of 7 mm and a thickness of 1.4 mm were wrapped with # 400 alumina abrasive grains using a double-side polishing machine.
【００４２】次に内周の下穴をあけ、内外周加工機を用
いて、内周面および外周面側面に所定の面取り加工を行
った。次いで両面研磨機を用いて、＃１０００のアルミ
ナ砥粒を用いて表裏面のラッピング処理を行った。引き
続いて上下定盤にポリッシャ用のポリウレタンパッド
（ロデールニッタ製ＭＨＣ１５Ａ）を用いて、研磨材と
して酸化セリウムを用いて１次ポリッシュを行った。Next, a prepared hole was formed on the inner periphery, and a predetermined chamfering process was performed on the inner peripheral surface and the outer peripheral surface side using an inner and outer peripheral processing machine. Next, using a double-side polishing machine, lapping treatment was performed on the front and back surfaces using # 1000 alumina abrasive grains. Subsequently, primary polishing was performed using a polyurethane pad for polisher (MHC15A manufactured by Rodel Nitta) on the upper and lower platens and cerium oxide as an abrasive.
【００４３】さらにＧＭＲへッド走行に適する平滑度を
得るために、表２に示したような通常加工と必要に応じ
て付随加工を加えた研磨加工を行った。研磨材として表
２に示した各含有率と平均粒径の酸化セリウムを用い、
ポリッシャにスエードウレタンパッドを用いて通常加工
としての最終ポリッシュを行い、その後、付随加工とし
て表２に示したように、付随加工を行わない場合、付随
加工として研磨用砥粒を含まない純水を流しながら研磨
を行う場合、および付随加工として研磨用砥粒を含まず
純水に界面活性剤を含ませた水を流しながら研磨を行う
場合とを実施した。Further, in order to obtain a smoothness suitable for running the GMR head, a polishing process was performed by adding a normal process as shown in Table 2 and, if necessary, an accompanying process. Using cerium oxide of each content and average particle size shown in Table 2 as an abrasive,
Using a suede urethane pad on the polisher, perform final polishing as normal processing, and then, as shown in Table 2, as auxiliary processing, when not performing auxiliary processing, pure water containing no abrasive grains for auxiliary processing. The polishing was carried out while flowing, and the polishing was carried out while flowing water in which pure water containing a surfactant was contained without containing abrasive grains for polishing as ancillary processing.
【００４４】[0044]
【表２】 ここに表２において、研磨レートは通常研磨と付随研磨
とを合わせた研磨量を合計時間で除したものである。ま
た通常研磨のみの場合は通常研磨における研磨レート
（研磨量／研磨時間）である。[Table 2] Here, in Table 2, the polishing rate is obtained by dividing the polishing amount of the normal polishing and the accompanying polishing by the total time. When only normal polishing is performed, the polishing rate is the polishing rate (polishing amount / polishing time) in normal polishing.
【００４５】（比較例７）研磨剤の酸化セリウムの含有
率を５０質量％とし、その平均粒径を２μｍとしたほか
は、実施例３〜１７と同様にして、付随研磨を行わない
研磨加工を行った。Comparative Example 7 Polishing processing without accompanying polishing was performed in the same manner as in Examples 3 to 17, except that the content of cerium oxide in the abrasive was 50% by mass and the average particle size was 2 μm. Was done.
【００４６】（比較例８）付随研磨として界面活性剤を
３０質量％含有する純水を流して研磨を行ったほかは実
施例３〜１７と同様の研磨加工を行った。Comparative Example 8 Polishing was performed in the same manner as in Examples 3 to 17, except that polishing was performed by flowing pure water containing 30% by mass of a surfactant as incidental polishing.
【００４７】以上の実施例３〜１７と比較例７〜８のガ
ラス基板を同一条件で化学強化した後に再度表面粗さ、
微小うねりの測定を行った。実施例１および２の場合と
同様に、表面粗さの測定値、Ｒａ，ＲＭＳおよびＲｙ
は、ＡＦＭで測定し、微小うねりＷA の測定は、ＺＹＧ
Ｏによって行った。After chemically strengthening the glass substrates of Examples 3 to 17 and Comparative Examples 7 to 8 under the same conditions, the surface roughness was again increased.
The measurement of minute waviness was performed. As in the case of Examples 1 and 2, measured values of surface roughness, Ra, RMS and Ry
It is measured by the AFM, measurement of micro-waviness W A is, ZYG
Performed by O.
【００４８】測定結果を表３に示す。また、本発明の実
施例及び比較例で得られた磁気ディスク用ガラス基板に
対して基板の表裏面にＣｒ下地層、ＣｏＰｔＣｒ磁性
層、炭素保護層を順次積層して磁気ディスクを得た。こ
の磁気ディスクをグラインドハイトテストを行った結果
と、実施例と比較例の評価結果（グラインドハイトテス
トのヘッドクラッシュの発生率）も合わせて表３に記載
した。Table 3 shows the measurement results. A magnetic disk was obtained by sequentially laminating a Cr underlayer, a CoPtCr magnetic layer, and a carbon protective layer on the front and back surfaces of the magnetic disk glass substrates obtained in Examples and Comparative Examples of the present invention. Table 3 also shows the results of the grind height test performed on the magnetic disk and the evaluation results of the examples and the comparative examples (incidence of head crash in the grind height test).
【００４９】[0049]
【表３】 ここに表３において、品質総合評価は、表面粗さ、微小
うねり、グラインドハイトテスト結果およびディフェク
ト発生率を総合評価して判定てたものである。また生産
性総合評価は、研磨時間、作業性、消耗品コストを総合
評価して判定したものである。ともに◎とても良好、○
良好、△不満足、そして×とても不満足、の４段階評価
で示した。[Table 3] Here, in Table 3, the comprehensive quality evaluation is determined by comprehensively evaluating the surface roughness, minute waviness, the result of the grind height test, and the defect occurrence rate. In addition, the comprehensive evaluation of productivity is determined by comprehensively evaluating polishing time, workability, and cost of consumables. Both are ◎ very good, ○
Good, Δ unsatisfactory, and × very unsatisfactory were given on a four-point scale.
【００５０】表３からも明らかになように、本発明によ
って製造された磁気ディスク用ガラス基板を用いれば、
高密度記録用磁気ディスクにおけるヘッドクラッシュの
原因となる磁気ディスク表面の微小突起が防止されるの
で、磁気ヘッドの低浮上化に好適であり、ＧＭＲヘッド
に対応できる高密度記録に適した磁気ディスク用ガラス
基板が製造できる。As is clear from Table 3, if the glass substrate for a magnetic disk manufactured according to the present invention is used,
Prevents minute protrusions on the surface of the magnetic disk that cause head crash in a magnetic disk for high-density recording, so it is suitable for lowering the flying height of the magnetic head and suitable for high-density recording compatible with GMR heads. Glass substrates can be manufactured.
【００５１】[0051]
【発明の効果】以上に述べたように、本発明によって製
造された磁気ディスク用ガラス基板を用いれば、高密度
記録用磁気ディスクにおけるヘッドクラッシュの原因と
なる磁気ディスク表面の微小突起が防止されるので、磁
気ヘッドの低浮上化に好適であり、ＧＭＲヘッドに対応
できる高密度記録に適した磁気ディスク用ガラス基板が
製造できる。As described above, the use of the glass substrate for a magnetic disk manufactured according to the present invention can prevent minute projections on the surface of the magnetic disk which cause a head crash in a magnetic disk for high density recording. Therefore, it is possible to manufacture a glass substrate for a magnetic disk that is suitable for lowering the flying height of the magnetic head and suitable for high-density recording that can be used for a GMR head.
Claims (7)
０．５ｎｍ以下、二乗平均粗さＲＭＳが０．６ｎｍ以下
であり、さらに微小うねりＷA が０．５ｎｍ以下である
ことを特徴とする磁気ディスク用ガラス基板。1. A following arithmetic average roughness Ra of the glass substrate surface is 0.5nm, root mean square roughness RMS is less than or equal 0.6 nm, and wherein the further micro-waviness W A is 0.5nm or less Glass substrate for magnetic disk.
と、前記ガラス基板の表面を研磨加工する工程と、表面
研磨された前記基板を溶融塩に浸漬してイオン交換によ
る化学強化処理を行う工程とを含む磁気ディスク用ガラ
ス基板の製造方法において、前記研磨加工する工程に用
いる研磨材中に酸化セリウムを６０質量％以上含有させ
て研磨を行う工程を有することを特徴とする磁気ディス
ク用ガラス基板の製造方法。2. A step of forming a glass material into a glass substrate, a step of polishing the surface of the glass substrate, and a step of immersing the surface-polished substrate in a molten salt and performing a chemical strengthening treatment by ion exchange. A method for manufacturing a glass substrate for a magnetic disk, comprising: a step of performing polishing by incorporating cerium oxide in a polishing material used in the step of polishing by 60% by mass or more. Manufacturing method.
５μｍ以上１．５μｍ以下の酸化セリウムを含有するも
のを用いて、研磨レートを０．１μｍ／分以上０．５μ
ｍ／分以下にて研磨することを特徴とする請求項２記載
の磁気ディスク用ガラス基板の製造方法。3. An abrasive having an average particle diameter D 50 of 0.3.
Polishing rate of 0.1 μm / min or more and 0.5 μm or more using a material containing cerium oxide of 5 μm or more and 1.5 μm or less.
3. The method for manufacturing a glass substrate for a magnetic disk according to claim 2, wherein the polishing is performed at a rate of not more than m / min.
と、前記ガラス基板の表面を研磨加工する工程と、表面
研磨された前記基板を溶融塩に浸漬してイオン交換によ
る化学強化処理を行う工程とを含む磁気ディスク用ガラ
ス基板の製造方法において、前記研磨加工する工程が研
磨材を含む液を用いて研磨する工程と、研磨材を含まな
い液を用いて研磨する工程とを含むことを特徴とする磁
気ディスク用ガラス基板の製造方法。4. A step of forming a glass material into a glass substrate, a step of polishing the surface of the glass substrate, and a step of immersing the surface-polished substrate in a molten salt and performing a chemical strengthening treatment by ion exchange. Wherein the step of polishing includes a step of polishing using a liquid containing an abrasive, and a step of polishing using a liquid containing no abrasive. Production method of a glass substrate for a magnetic disk.
リウムを６０質量％以上含有した懸濁液であり、前記研
磨材を含まない液が水または水に界面活性剤を添加した
溶液であることを特徴とする請求項４記載の磁気ディス
ク用ガラス基板の製造方法。5. The liquid containing an abrasive is a suspension containing 60% by mass or more of cerium oxide in the abrasive, and the liquid not containing the abrasive is water or a solution obtained by adding a surfactant to water. The method for manufacturing a glass substrate for a magnetic disk according to claim 4, wherein
上３０質量％未満であることを特徴とする請求項５記載
の磁気ディスク用ガラス基板の製造方法。6. The method according to claim 5, wherein the concentration of the surfactant is 0.5% by mass or more and less than 30% by mass.
粗さＲａを０．５ｎｍ以下、二乗平均粗さＲＭＳを０．
６ｎｍ以下、微小うねりＷA を０．５ｎｍ以下にするこ
とを特徴とする請求項２ないし６のいずれか１項記載の
磁気ディスク用ガラス基板の製造方法。7. The glass substrate surface after chemical strengthening has an arithmetic mean roughness Ra of 0.5 nm or less and a root mean square roughness RMS of not more than 0.5 nm.
6nm or less, waviness W A of claims 2 to 6 any one method of manufacturing a glass substrate for a magnetic disk according to, characterized in that the 0.5nm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34941299A JP2001167430A (en) | 1999-12-08 | 1999-12-08 | Substrate for magnetic disk and its manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34941299A JP2001167430A (en) | 1999-12-08 | 1999-12-08 | Substrate for magnetic disk and its manufacturing method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2001167430A true JP2001167430A (en) | 2001-06-22 |
Family
ID=18403583
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP34941299A Withdrawn JP2001167430A (en) | 1999-12-08 | 1999-12-08 | Substrate for magnetic disk and its manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2001167430A (en) |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006021259A (en) * | 2004-07-06 | 2006-01-26 | Fuji Electric Device Technology Co Ltd | Polishing method of magnetic disk base board and magnetic disk medium |
| WO2006025509A1 (en) * | 2004-08-30 | 2006-03-09 | Showa Denko K.K. | Magnetic disk substrate and production method of magnetic disk |
| WO2007099799A1 (en) * | 2006-03-01 | 2007-09-07 | Mitsui Mining & Smelting Co., Ltd. | Cerium-based abrasive material |
| CN100382150C (en) * | 2004-01-14 | 2008-04-16 | 日立环球储存科技荷兰有限公司 | Engineered interface for low fly height |
| JP2009123327A (en) * | 2008-12-24 | 2009-06-04 | Hoya Corp | Method of manufacturing magnetic disk |
| JP2009176415A (en) * | 2009-04-30 | 2009-08-06 | Hoya Corp | Glass substrate for magnetic disk, magnetic disk, and method of manufacturing glass substrate for magnetic disk |
| WO2012042735A1 (en) * | 2010-09-30 | 2012-04-05 | コニカミノルタオプト株式会社 | Manufacturing method for glass substrate for information recording medium |
| JP2012079369A (en) * | 2010-09-30 | 2012-04-19 | Konica Minolta Opto Inc | Method for manufacturing glass substrate for information recording medium |
| JP2012109019A (en) * | 2010-02-01 | 2012-06-07 | Asahi Glass Co Ltd | Glass substrate for magnetic recording medium |
| US8241516B2 (en) | 2003-08-08 | 2012-08-14 | Kao Corporation | Substrate for magnetic disk |
| JP2016110689A (en) * | 2013-12-26 | 2016-06-20 | Hoya株式会社 | Magnetic disk substrate, magnetic disk, and magnetic disk drive device |
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-
1999
- 1999-12-08 JP JP34941299A patent/JP2001167430A/en not_active Withdrawn
Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8241516B2 (en) | 2003-08-08 | 2012-08-14 | Kao Corporation | Substrate for magnetic disk |
| CN100382150C (en) * | 2004-01-14 | 2008-04-16 | 日立环球储存科技荷兰有限公司 | Engineered interface for low fly height |
| JP2006021259A (en) * | 2004-07-06 | 2006-01-26 | Fuji Electric Device Technology Co Ltd | Polishing method of magnetic disk base board and magnetic disk medium |
| WO2006025509A1 (en) * | 2004-08-30 | 2006-03-09 | Showa Denko K.K. | Magnetic disk substrate and production method of magnetic disk |
| JP2007231158A (en) * | 2006-03-01 | 2007-09-13 | Mitsui Mining & Smelting Co Ltd | Cerium-based abrasive |
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| WO2007099799A1 (en) * | 2006-03-01 | 2007-09-07 | Mitsui Mining & Smelting Co., Ltd. | Cerium-based abrasive material |
| JP4484160B2 (en) * | 2008-12-24 | 2010-06-16 | Ｈｏｙａ株式会社 | Manufacturing method of glass substrate for magnetic disk |
| JP2009123327A (en) * | 2008-12-24 | 2009-06-04 | Hoya Corp | Method of manufacturing magnetic disk |
| JP2009176415A (en) * | 2009-04-30 | 2009-08-06 | Hoya Corp | Glass substrate for magnetic disk, magnetic disk, and method of manufacturing glass substrate for magnetic disk |
| JP4484162B2 (en) * | 2009-04-30 | 2010-06-16 | Ｈｏｙａ株式会社 | Glass substrate for magnetic disk, magnetic disk, and method for manufacturing glass substrate for magnetic disk |
| JP2012109019A (en) * | 2010-02-01 | 2012-06-07 | Asahi Glass Co Ltd | Glass substrate for magnetic recording medium |
| JP2012079369A (en) * | 2010-09-30 | 2012-04-19 | Konica Minolta Opto Inc | Method for manufacturing glass substrate for information recording medium |
| WO2012042735A1 (en) * | 2010-09-30 | 2012-04-05 | コニカミノルタオプト株式会社 | Manufacturing method for glass substrate for information recording medium |
| JPWO2012042735A1 (en) * | 2010-09-30 | 2014-02-03 | コニカミノルタ株式会社 | Manufacturing method of glass substrate for information recording medium |
| JP2016110689A (en) * | 2013-12-26 | 2016-06-20 | Hoya株式会社 | Magnetic disk substrate, magnetic disk, and magnetic disk drive device |
| JP2020075824A (en) * | 2018-11-05 | 2020-05-21 | 日本電気硝子株式会社 | Method for manufacturing glass panel |
| JP7225687B2 (en) | 2018-11-05 | 2023-02-21 | 日本電気硝子株式会社 | Glass plate manufacturing method |
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