JPH02162527A - Production of magnetic recording medium - Google Patents
Production of magnetic recording mediumInfo
- Publication number
- JPH02162527A JPH02162527A JP63317708A JP31770888A JPH02162527A JP H02162527 A JPH02162527 A JP H02162527A JP 63317708 A JP63317708 A JP 63317708A JP 31770888 A JP31770888 A JP 31770888A JP H02162527 A JPH02162527 A JP H02162527A
- Authority
- JP
- Japan
- Prior art keywords
- substrate
- sputtering
- recording medium
- intermediate electrode
- magnetic recording
- 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.)
- Granted
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 10
- 239000000758 substrate Substances 0.000 claims abstract description 37
- 238000004544 sputter deposition Methods 0.000 claims abstract description 24
- 239000010409 thin film Substances 0.000 claims description 16
- 229910052751 metal Inorganic materials 0.000 claims description 8
- 239000002184 metal Substances 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 6
- 229910017052 cobalt Inorganic materials 0.000 claims description 5
- 239000010941 cobalt Substances 0.000 claims description 5
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 5
- 229910045601 alloy Inorganic materials 0.000 abstract description 8
- 239000000956 alloy Substances 0.000 abstract description 8
- 229910052804 chromium Inorganic materials 0.000 abstract description 3
- 229910052684 Cerium Inorganic materials 0.000 abstract description 2
- 229910052693 Europium Inorganic materials 0.000 abstract description 2
- 229910052779 Neodymium Inorganic materials 0.000 abstract description 2
- 229910052777 Praseodymium Inorganic materials 0.000 abstract description 2
- 229910052772 Samarium Inorganic materials 0.000 abstract description 2
- 229910052785 arsenic Inorganic materials 0.000 abstract description 2
- 229910052791 calcium Inorganic materials 0.000 abstract description 2
- 229910052735 hafnium Inorganic materials 0.000 abstract description 2
- 229910052750 molybdenum Inorganic materials 0.000 abstract description 2
- 229910052759 nickel Inorganic materials 0.000 abstract description 2
- 229910052758 niobium Inorganic materials 0.000 abstract description 2
- 229910052697 platinum Inorganic materials 0.000 abstract description 2
- 229910052702 rhenium Inorganic materials 0.000 abstract description 2
- 229910052703 rhodium Inorganic materials 0.000 abstract description 2
- 229910052707 ruthenium Inorganic materials 0.000 abstract description 2
- 229910052715 tantalum Inorganic materials 0.000 abstract description 2
- 229910052719 titanium Inorganic materials 0.000 abstract description 2
- 229910052721 tungsten Inorganic materials 0.000 abstract description 2
- 229910052720 vanadium Inorganic materials 0.000 abstract description 2
- 229910000531 Co alloy Inorganic materials 0.000 abstract 3
- 229910052787 antimony Inorganic materials 0.000 abstract 1
- 229910052741 iridium Inorganic materials 0.000 abstract 1
- 229910052762 osmium Inorganic materials 0.000 abstract 1
- 229910052710 silicon Inorganic materials 0.000 abstract 1
- 229910052709 silver Inorganic materials 0.000 abstract 1
- 229910052727 yttrium Inorganic materials 0.000 abstract 1
- 229910052726 zirconium Inorganic materials 0.000 abstract 1
- 239000010408 film Substances 0.000 description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 229910001004 magnetic alloy Inorganic materials 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000001755 magnetron sputter deposition Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910001096 P alloy Inorganic materials 0.000 description 1
- 229910001362 Ta alloys Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007772 electroless plating Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 230000010365 information processing Effects 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
Landscapes
- Manufacturing Of Magnetic Record Carriers (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は磁気記録媒体の製造法に係り、詳しくは、高い
保磁力を有する磁気記録媒体を製造する方法に関するも
のである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a magnetic recording medium, and more particularly, to a method for manufacturing a magnetic recording medium having a high coercive force.
［従来の技術］
近年、コンピュータ等の情報処理技術の発達に伴い、そ
の外部記憶装置に用いられる磁気ディスクなどの磁気記
録媒体に対し、高密度記録化への要求がますます高めら
れている。[Background Art] In recent years, with the development of information processing technology for computers and the like, there has been an increasing demand for higher density recording in magnetic recording media such as magnetic disks used in external storage devices.
現在、長手記録用磁気ディスクに用いられる磁気記録媒
体の磁性層としては、スパッタリング等によりＣｒ下地
薄膜上に、エピタキシャル的に成膜されたｃｏ系合金薄
膜が主流となってきている。しかして、このＣｏ系合金
薄膜磁性層についても、高密度記録化への要求に対し、
磁気特性としてより高い保磁力を付与することが必要と
されており、従来より、その特性についての報告が数多
くなされている。（例えば、”Ｎｅｗｌｏｎｇｉｔｕｄ
ｉｎａｌ ｒｅｃｏｒｄｉｎｇ ｍｅｄｉａ Ｃ
０ＩＩＮＩ、 Ｃｒ。At present, as the magnetic layer of a magnetic recording medium used in a magnetic disk for longitudinal recording, a co-based alloy thin film epitaxially formed on a Cr underlayer thin film by sputtering or the like has become mainstream. However, regarding this Co-based alloy thin film magnetic layer, in response to the demand for higher density recording,
It is necessary to impart higher coercive force as a magnetic property, and there have been many reports regarding this property. (For example, “Newlongitud
inal recording media C
0IINI, Cr.
ｆｒｏｍ ｈｉｇｈ ｒａｔｅ ５ｔａｔｉｃ ｍａｇ
ｎｅｔｒｏｎ ｓｐｕｔｔｅｒ−ｉｎｇｓｙ、ｓｔｅｍ
ＩＥＥＥ ＴｒａｎＳｏＭａｇｎ、 Ｍａｇ−２２
，Ｎｏ５゜（１９８Ｂ）、 ３３４；特開昭６３−７９
２３３号公報；特開昭６３−７９９６８号公報、）
［発明が解決しようとする課Ｂ］
従来報告されているように、Ｃｏ系合金薄膜磁性層の保
磁力は、Ｃｒ下地薄膜の膜厚とともに増大する。しかし
ながら、ある上限値を超えると飽相持性を示し、それ以
上の高保磁力化は困難である。また、この保磁力は、Ｃ
ｏ系合金薄膜の膜厚の低減により増加する。しかしなが
ら、膜厚の低減は再生出力値の低下につながるため、実
用上、所定の膜厚以下に薄くすることは困難である。更
に、磁性層の成膜時における成膜ガス圧力、基板温度な
どのスパッタ条件の選択により、ある程度の保磁力の向
上は可能であるが、その向上効果は小さいものである。from high rate 5tatic mag
netron sputter-ingsy, stem
IEEE TranSoMagn, Mag-22
, No. 5゜ (198B), 334; JP-A-63-79
(No. 233; Japanese Unexamined Patent Publication No. 63-79968) [Problem B to be solved by the invention] As previously reported, the coercive force of a Co-based alloy thin film magnetic layer increases with the thickness of the Cr underlayer thin film. increase However, when a certain upper limit is exceeded, saturation is exhibited, and it is difficult to increase the coercive force further. Also, this coercive force is C
It increases by reducing the thickness of the o-based alloy thin film. However, since reducing the film thickness leads to a decrease in the reproduction output value, it is practically difficult to reduce the film thickness to a predetermined thickness or less. Further, although it is possible to improve the coercive force to some extent by selecting sputtering conditions such as the deposition gas pressure and substrate temperature during deposition of the magnetic layer, the improvement effect is small.
本発明は上記従来の問題点を解決し、著しく高い保磁力
を有する磁気記録媒体を製造する方法を提供することを
目的とする。SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and provide a method for manufacturing a magnetic recording medium having an extremely high coercive force.
［課題を解決するための手段］
本発明の磁気記録媒体の製造法は、基板上に磁性金属薄
膜をスパッタリングによって成膜する磁気記録媒体の製
造方法において、ターゲ９トの外周部近傍に中間電極を
設け、該中間電極を成膜装置本体の接地部に対して正の
電位に印加し、且つ、基板側に負のバイアス電圧を印加
した状態で、コバルトを主成分とする磁性金属薄膜を形
成することを特徴とする。[Means for Solving the Problems] The method of manufacturing a magnetic recording medium of the present invention is a method of manufacturing a magnetic recording medium in which a magnetic metal thin film is formed on a substrate by sputtering. A magnetic metal thin film containing cobalt as a main component is formed by applying a positive potential to the intermediate electrode with respect to the grounding part of the film forming apparatus main body, and applying a negative bias voltage to the substrate side. It is characterized by
即ち、本発明者等は上記従来の状況に鑑み、磁気記録媒
体の保磁力を更に向上させるべく鋭意検討を重ねた結果
、ターゲットの外周部近傍に中間電極を設け、該中間電
極を基板に対°して正の電位に印加した状態で、且つ、
基板側に負の電圧を印加しながらスパッタリングを行う
所謂バイアススパッタリング装置を用いて、基板側に負
の電圧を印加しながら特定の磁性合金薄膜、即ち、コバ
ルト（ＣＯ）を主成分とする磁性金属薄膜を基板上にス
パッタリングによって形成することにより、磁気記録媒
体の保磁力が著しく向上することを見出し、本発明を完
成するに至った。That is, in view of the above-mentioned conventional situation, the inventors of the present invention have made extensive studies to further improve the coercive force of magnetic recording media, and as a result, they have provided an intermediate electrode near the outer periphery of the target and placed the intermediate electrode against the substrate. ° with a positive potential applied, and
Using a so-called bias sputtering device that performs sputtering while applying a negative voltage to the substrate side, a specific magnetic alloy thin film, that is, a magnetic metal whose main component is cobalt (CO), is sputtered while applying a negative voltage to the substrate side. The present inventors have discovered that the coercive force of a magnetic recording medium can be significantly improved by forming a thin film on a substrate by sputtering, and have completed the present invention.
以下に本発明を図面を参照して詳細に説明する。The present invention will be explained in detail below with reference to the drawings.
第１図は本発明の実施に好適なスパッタリング装置の一
例を示す概略構成図である。図中、１はターゲットであ
り、これに対向した位置に基板ホルダー２が設けられて
おり、基板ホルダー２には基板３が装着されている。基
板ホルダー２は基板３を連続的に成膜で跨るように移動
可能とされている。４はこのようなスパッタリング装置
本体の接地部に対して正の電位を印加させるためにター
ゲット１の外周部近傍に設置された中間電極である。５
はターゲット１と中間電極４に接続されるスパッタリン
グ用電源である。６はスパッタリング装置本体の接地部
と中間電極４に接続される中ｒｊＪ！極用電源である。FIG. 1 is a schematic diagram showing an example of a sputtering apparatus suitable for implementing the present invention. In the figure, 1 is a target, and a substrate holder 2 is provided at a position opposite to the target, and a substrate 3 is mounted on the substrate holder 2. The substrate holder 2 is movable so as to continuously straddle the substrate 3 during film formation. Reference numeral 4 denotes an intermediate electrode installed near the outer periphery of the target 1 in order to apply a positive potential to the ground portion of the main body of the sputtering apparatus. 5
is a sputtering power supply connected to the target 1 and the intermediate electrode 4. 6 is connected to the grounding part of the sputtering apparatus main body and the intermediate electrode 4. This is a power supply for poles.
７は基板ホルダー２に負のバイアス電圧を印加させるた
めのバイアス電源である。Reference numeral 7 denotes a bias power supply for applying a negative bias voltage to the substrate holder 2.
これらスパッタリング用電源５、中間電極用電源６及び
バイアス電源７としては直流電源が好ましいが、ＲＦ電
源も使用できる。スパッタリング装置としては、通常の
ＤＣマグネトロンスパッタリング装置又はＲＦマグネト
ロンスパッタリング装置等が採用される。As these sputtering power source 5, intermediate electrode power source 6, and bias power source 7, DC power sources are preferable, but RF power sources can also be used. As the sputtering device, a normal DC magnetron sputtering device, an RF magnetron sputtering device, or the like is employed.
ターゲット１としては、Ｃｏ−Ｃｒ。Target 1 is Co-Cr.
Ｃｏ−Ｃｒ−Ｘ、 Ｃｏ−Ｎ１−Ｘ、 Ｃｏ−Ｗ−Ｘ等
で表わされるＣＯを主成分とするｃｏ系合金が使用され
る。ここでＸとしてはＬｉ、Ｓｔ。Co-based alloys whose main component is CO, such as Co-Cr-X, Co-N1-X, Co-W-X, etc., are used. Here, X is Li, St.
Ｃａ、 Ｔｉ ％ Ｖ、 Ｃｒ％ Ｎｉ、 Ａｓ
、 Ｙ、、Ｚｒ。Ca, Ti% V, Cr% Ni, As
,Y,,Zr.
Ｎｂ、 Ｍｏ、 Ｒｕ、 Ｒｈ％ Ａｇ、 Ｓ
ｂ、 Ｈｆ。Nb, Mo, Ru, Rh% Ag, S
b, Hf.
Ｔａ ％ Ｗ、 Ｒｅ、 Ｏｓ、 Ｉ ｒ ％
Ｐｔ、 Ａｕ。Ta % W, Re, Os, I r %
Pt, Au.
Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ及びＥｕよりなる
群から選ばれる１種又は２種以上の元素が用いられる。One or more elements selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm and Eu are used.
また、基板３としては一般にアルミニウム又はアルミニ
ウム合金基板が用いられ、通常、アルミニウム基板を所
定の厚さに加工した後、その表面を鏡面加工したものに
、・第１次下地層として硬質非磁性金属、例えばＮ１−
Ｐ合金を無電解メツキ或いは陽極酸化処理により形成し
、しかる後、第２次下地層としてＣｒをスパッタリング
したものが用いられる。基板３としては、上記第１次下
地層を形成せずに、鏡面加工したアルミニウム基板上に
直接下地層としてＣｒをスパッタリングしたものを用い
ることもできる。In addition, an aluminum or aluminum alloy substrate is generally used as the substrate 3, and after processing the aluminum substrate to a predetermined thickness, the surface is mirror-finished, and a hard non-magnetic metal is used as the first underlayer. , for example N1-
A P alloy is formed by electroless plating or anodic oxidation, and then Cr is sputtered as the second underlayer. As the substrate 3, it is also possible to use a substrate in which Cr is sputtered directly as a base layer on a mirror-finished aluminum substrate without forming the primary base layer.
第１図に示すスパッタリング装置を用いて、本発明の方
法に従って、磁気記録媒体を製造するには、・まず、上
述の如き基板３を装置の基板ホルダー２に取り付け、前
記Ｃｏ系合金のターゲット２を用いて、アルゴン（Ａｒ
）等の希ガスの存在下でスパッタリングを行なうが、こ
の際、中間電極４に、スパッタリング装置本体の接地部
に対して正げ電極、例えば、１００ＯＶ以下、好ましく
は５０〜ｓ ｏ ｏ ｖ、更に好ましくは１００〜４０
０ｖの電位を印加した状態で、且つ、基板ホルダー２に
は負のバイアス電圧を印加した状態、即ち、バイアス電
源７により基板ホルダー２に例えば−１０００■以上、
好ましくは−５０〜−５００Ｖ、更に好ましくは−１０
０〜−４００■の電圧を印加した状態でスパッタリング
を行な、い、基板３上にＣｏ系合金の磁性金属薄膜を形
成する。To manufacture a magnetic recording medium according to the method of the present invention using the sputtering apparatus shown in FIG. 1, first, attach the substrate 3 as described above to the substrate holder 2 of the apparatus, and using argon (Ar
) Sputtering is performed in the presence of a rare gas such as Preferably 100-40
In a state where a potential of 0 V is applied and a negative bias voltage is applied to the substrate holder 2, that is, the bias power supply 7 applies a voltage of -100V or more to the substrate holder 2, for example.
Preferably -50 to -500V, more preferably -10
Sputtering is performed with a voltage of 0 to -400 .mu. applied to form a magnetic metal thin film of a Co-based alloy on the substrate 3.
本発明において、スパッタリング条件としては、通常、
磁気記録媒体の磁性層を形成させる際に採用される条件
を採用することができる。例えば、真空排気したチャン
バー内圧力をｌＸｌ０−’７ｏｒｒ以下、Ａｒ等の希ガ
ス圧力を０．５×１０−ｇ〜２ ｘ １０−２Ｔ ｏ
ｒ ｒ、望ましくは１×１０−’〜５ ｘ １０−”Ｔ
ｏ ｒ ｒの範囲で、基板温度を１５０℃以上、望ま
しくは２００〜３００℃の範囲の条件下でスパッタリン
グを実施することができる。In the present invention, the sputtering conditions are usually as follows:
Conditions employed when forming a magnetic layer of a magnetic recording medium can be employed. For example, the pressure inside the evacuated chamber is 1Xl0-'7 orr or less, and the pressure of rare gas such as Ar is 0.5 x 10-g to 2 x 10-2T o
r r, preferably 1 x 10-' to 5 x 10-''T
Sputtering can be carried out under conditions in which the substrate temperature is 150°C or higher, preferably 200 to 300°C.
このようなスパッタリングにより形成する磁性合金薄膜
層の膜厚は、残留磁性密度（Ｂｒ）と磁性合金薄膜層の
膜厚（１）との積（Ｂｒ−ｔ）が３００〜７００Ｇ・μ
ｍとなるような膜厚とするのが好ましい。The thickness of the magnetic alloy thin film layer formed by such sputtering is such that the product (Br-t) of the residual magnetic density (Br) and the film thickness (1) of the magnetic alloy thin film layer is 300 to 700 G·μ.
It is preferable to set the film thickness to m.
［作用］
ターゲットの外周部近傍に中間電極を設け、該中間電極
を成膜装置本体の接地部に対して正の電位に印加した状
態で、且つ、基板側に負のバイアス電圧を印加した状態
でスパッタリングにより形成されたＣｏ系合金の磁性金
属薄膜層により、高い保磁力を有する高特性磁性層が形
成される。[Operation] An intermediate electrode is provided near the outer periphery of the target, and a positive potential is applied to the intermediate electrode with respect to the grounding part of the film forming apparatus main body, and a negative bias voltage is applied to the substrate side. A magnetic metal thin film layer of a Co-based alloy formed by sputtering in the step forms a high-performance magnetic layer having a high coercive force.
［実施例］
以下に実施例及び比較例を挙げ、て本発明をより具体的
に説明するが、本発明はその要旨を超えない限り、以下
の実施例に限定されるものではない。[Examples] The present invention will be described in more detail with reference to Examples and Comparative Examples below, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.
実施例１〜６、比較例１〜８
第１図に示す装置を用い、下地層としてＣｒ薄膜（膜厚
２０００Ａ）を形成したアルミニウム基板３及び、Ｃｏ
−Ｃｒ−Ｔａ合金ターゲット１を用いて中間電極４に第
１表に示す電位を印加し、且つ、バイアス電源７に第１
表に示す電圧を印加させた状態で、チャンバー内圧力１
×１０″″８Ｔｏｒｒ以下、アルゴンガス圧力２Ｘ１０
−３Ｔｏｒｒ、基板温度２５０℃の条件下でスパッタリ
ングを行ない、基板上に８６原子％Ｃｏ−１２原子％Ｃ
ｒ−２原子％Ｔａ磁性層（４ｏｏＧ・μｍ）を形成した
。Examples 1 to 6, Comparative Examples 1 to 8 Using the apparatus shown in FIG. 1, an aluminum substrate 3 and a Co
- Using the Cr-Ta alloy target 1, apply the potential shown in Table 1 to the intermediate electrode 4, and apply the potential shown in Table 1 to the bias power source 7.
With the voltage shown in the table applied, the chamber pressure 1
×10″″8 Torr or less, argon gas pressure 2×10
Sputtering was performed under the conditions of -3 Torr and a substrate temperature of 250°C, and 86 at.%Co-12 at.%C was deposited on the substrate.
An r-2 atomic % Ta magnetic layer (4ooG·μm) was formed.
得られた磁気ディスクの保磁力を試料振動型磁力計で測
定し、結果を第１表に示した。The coercive force of the obtained magnetic disk was measured using a sample vibrating magnetometer, and the results are shown in Table 1.
第 １ 表
［発明の効果］
以上詳述した通り、本発明の磁気記録媒体の製造法によ
れば、高い保磁力を有する高特性磁気記録媒体を容易に
製造することができ磁気記録媒体のより一層の高密度記
録化が可能とされる。Table 1 [Effects of the Invention] As detailed above, according to the method for manufacturing a magnetic recording medium of the present invention, a high-performance magnetic recording medium having a high coercive force can be easily manufactured, and the magnetic recording medium can be improved. It is possible to achieve even higher density recording.
第１図は本発明の実施に好適なスパッタリング装置の一
例を示す概略構成図である。
１・・・ターゲット、
２・・・基板ホルダー
３・・・基板、
４・・・中間電極、
５・・・スパッタリング用電源、
６・・・中間電極用電源、
７・・・バイアス電源。FIG. 1 is a schematic diagram showing an example of a sputtering apparatus suitable for implementing the present invention. DESCRIPTION OF SYMBOLS 1...Target, 2...Substrate holder 3...Substrate, 4...Intermediate electrode, 5...Power source for sputtering, 6...Power source for intermediate electrode, 7...Bias power source.
Claims (1)
成膜する磁気記録媒体の製造方法において、ターゲット
の外周部近傍に中間電極を設け、該中間電極を成膜装置
本体の接地部に対して正の電位に印加し、且つ、基板側
に負のバイアス電圧を印加した状態で、コバルトを主成
分とする磁性金属薄膜を形成することを特徴とする磁気
記録媒体の製造法。(1) In a method for manufacturing a magnetic recording medium in which a magnetic metal thin film is deposited on a substrate by sputtering, an intermediate electrode is provided near the outer periphery of the target, and the intermediate electrode is placed in a positive position with respect to the grounding part of the main body of the film-forming apparatus. 1. A method of manufacturing a magnetic recording medium, comprising forming a magnetic metal thin film containing cobalt as a main component while applying a potential and applying a negative bias voltage to a substrate side.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63317708A JPH02162527A (en) | 1988-12-16 | 1988-12-16 | Production of magnetic recording medium |
| KR1019890009884A KR970002340B1 (en) | 1988-07-15 | 1989-07-11 | Method for producing magnetic recording medium |
| US07/378,963 US4997539A (en) | 1988-07-15 | 1989-07-12 | Method and apparatus for producing a magnetic recording medium |
| DE89112903T DE68913837D1 (en) | 1988-07-15 | 1989-07-13 | Method and device for producing a magnetic recording medium. |
| EP89112903A EP0350940B1 (en) | 1988-07-15 | 1989-07-13 | Method and apparatus for producing a magnetic recording medium |
| SG113994A SG113994G (en) | 1988-07-15 | 1994-08-13 | Method and apparatus for producing a magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63317708A JPH02162527A (en) | 1988-12-16 | 1988-12-16 | Production of magnetic recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02162527A true JPH02162527A (en) | 1990-06-22 |
| JPH0572016B2 JPH0572016B2 (en) | 1993-10-08 |
Family
ID=18091147
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63317708A Granted JPH02162527A (en) | 1988-07-15 | 1988-12-16 | Production of magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02162527A (en) |
-
1988
- 1988-12-16 JP JP63317708A patent/JPH02162527A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0572016B2 (en) | 1993-10-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |