CN1178025A - Magnetic recording medium and method of manufacturing same - Google Patents
Magnetic recording medium and method of manufacturing same Download PDFInfo
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- CN1178025A CN1178025A CN 95197757 CN95197757A CN1178025A CN 1178025 A CN1178025 A CN 1178025A CN 95197757 CN95197757 CN 95197757 CN 95197757 A CN95197757 A CN 95197757A CN 1178025 A CN1178025 A CN 1178025A
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Abstract
A mass-producible magnetic recording medium having a ferromagnetic metal layer comprising colvicr or Cocrpt alloy, which has a high S/N ratio of electromagnetic conversion and a stable coecive force. The magnetic recording medium, using magnetic inversion, has a ferromagnetic metal layer comprising CoNiCr or CoCrPt formed on a surface of a substrate with a metallic base layer therebetween. The ferromagnetic metal layer has an oxygen concentration of not more than 100 wt ppm and contains crystal grains with an amorphous grain boundary. In the manufacturing process according to the present invention, the metallic base layer and/or the ferromagnetic metal layer is formed on the substrate at surface temp. of 60-150 degree C.
Description
Technical field
The present invention relates to magnetic recording medium and manufacture method thereof.Specifically, the present invention relates to following high density magnetic record medium and manufacture method thereof, this magnetic recording medium has high coercive force and standard coercive force, and has good S/N ratio.Magnetic recording medium of the present invention is particularly suitable for hard disc, flexible plastic disc and tape etc.
Background technology
Knew already that existing magnetic recording medium and manufacture method thereof comprised following technology.
Figure 10 is the synoptic diagram as the hard disc of an example of magnetic recording medium.In Figure 10, Figure 10 (a) is the whole oblique view of magnetic recording medium, Figure 10 (b) along being the part sectioned view of A-A ' line among Figure 10 (a).
As matrix 1, the matrix of non magnetic (Ni-P) layer 3 is set on the surface of use Al substrate 2.Afterwards, on this matrix 1, stack gradually Cr lining 4, ferromagnetism metal level 5 and protective seam 6.
Form non magnetic (Ni-P) layer 3 by electrochemical plating or sputtering method on following A l substrate 2 surfaces, thereby form matrix 1, this Al substrate 2 is a disc, and its diameter is 89mm (3.5 inches), and its thickness is 1.27mm (50 mil).In addition, handle, go up on non magnetic (Ni-P) layer 3 surface and form the vestige (back is called texture) that is circular concentric by mechanical lapping.In general, non magnetic (Ni-P) layer surfaceness of 3, promptly the average centerline roughness Ra when radial direction is measured is 5nm～15nm.In addition, Cr lining 4 and ferromagnetism metal level 5 (being generally Co alloy system magnetic film) are formed at by sputtering method on the surface of above-mentioned matrix 1, by the protective seam 6 of formations such as sputtering method formation carbon, the surface of ferromagnetism metal level 5 are protected at last.The thickness of typical each layer is following value, promptly non magnetic (Ni-P) layer 3:5 μ m～15 μ m, Cr lining 4:50nm～150nm, ferromagnetism metal level 5:30nm～100nm, protective seam 6:20nm～50nm.
Existing magnetic recording medium with above-mentioned layer structure is to make under following condition, and this condition is: the vacuum tightness that film forming room reached before the spatter film forming is 10
-7Torr,, and the impurity concentration in the Al gas that is adopted during film forming is more than 1ppm.
In the magnetic recording medium that obtains according to above-mentioned manufacture method, particularly contain the ferromagnetism metal level 5 of Ta element (such as, CoCrTa alloy magnetic film) occasion, have the grain boundary layer that amorphous structure forms at the intergranule that forms the ferromagnetism metal level, and this grain boundary layer is made up of nonmagnetic alloy and is constituted, these are by people such as middle well report (J.Nakai, E.Kusumoto, M.Kuwabara, T.Miyamoto, M.R.Visokay, K.Yoshikawa and K.Itayama, " Relation BetweenMicrostructure of Grain Boundary and the Intergranular Exchange in CoCrTa ThinFilm for Longitudinal Recording Media ", IEEE Trans.Magn., vol.30, No.6, pp.3969,1994).
But, do not contain the ferromagnetism metal level of Ta element (such as, CoNiCr or CoCrPt alloy magnetic film) occasion, do not see having above-mentioned grain boundary layer.
In addition, above-mentioned document also points out to contain at the ferromagnetism metal level occasion of Ta element, and the standard coercive force of magnetic recording medium (is expressed as Hc/Hk
Grain) have value greater than 0.3, relative therewith, in the occasion that does not contain Ta, then above-mentioned coercive force is less than 0.3.
In addition, following technology is disclosed in International Patent Application PCT/JP94/01184 communique, this technology relates to a kind of high density magnetic record medium and manufacture method thereof of cheapness, this magnetic recording medium is under the situation of the ferromagnetism metal level that does not adopt high price, has high coercive force, on matrix surface, forming the ferromagnetism metal level by metal lining, utilize in the magnetic recording medium of flux reversal, impurity concentration when making film forming in the employed Ar gas remains on below the 10ppb, make metal lining or/and the oxygen concentration of ferromagnetism metal level below 100ppm (weight).In addition, above-mentioned document is also pointed out, because before forming above-mentioned metal lining, use the Ar gas of its impurity concentration below 10ppb, by high-frequency sputtering above-mentioned matrix surface is carried out cleaning, make above-mentioned matrix surface remove 0.2nm～1nm, can further increase coercive force like this.Above-mentioned document also points out to have correlativity between the standard coercive force of magnetic recording medium and the media noise, in order to obtain the lower medium of noise, the standard coercive force should be set in more than 0.3, below 0.5.
The standard coercive force of magnetic recording medium (is expressed as Hc/Hk
Grain) refer to the anisotropy field Hk of coercivity H and crystal grain
GrainRatio, expression crystal grain is every the raising degree of magnetic.That is, the standard coercive force height of ferromagnetism metal level means that the magnetic interaction of each crystal grain that constitutes the ferromagnetism metal level reduces, thereby can obtain high coercive force.
In addition we know the road is carrying out higher high frequency recording so that realize the occasion of high density recording, and the transitional region of flux reversal constitutes noise source to tracer signal.That is, big in the confusion of above-mentioned transitional region, or the bigger occasion of scope, can form following magnetic recording medium, the noise in this magnetic recording medium uprises trend to be increased, and recording is poor.
Existing magnetic recording medium is the occasion of CoCrTa alloy magnetic film at the ferromagnetism metal level, obtains the lower medium of noise really easily, is the occasion of CoNiCr or CoCrPt alloy magnetic film at the ferromagnetism metal level, and above-mentioned noise trend increases.
Because the magnetic recording medium with ferromagnetism metal level of being made up of CoCrTa alloy magnetic film is subjected to the influence of film forming atmosphere easily, be difficult to be manufactured on the medium of the high-coercive force that keeps stable when producing in enormous quantities like this.Relative therewith, be the occasion of CoNiCr or CoCrPt alloy magnetic film at the ferromagnetism metal level, have when producing in enormous quantities stably to obtain coercitive advantage.
Therefore, be desirable to provide a kind of magnetic recording medium and manufacture method thereof, this magnetic recording medium has by can stably obtain the ferromagnetism metal level that coercitive CoNiCr or CoCrPt alloy magnetic film are formed when producing in enormous quantities, keep the high characteristics of S/N ratio (S represents tracer signal, N presentation medium noise) in the electromagnetic conversion characteristics.
The 1st purpose of the present invention is to provide a kind of magnetic recording medium, this magnetic recording medium has the ferromagnetism metal level of being made up of CoNiCr or CoCrPt alloy magnetic film, (S represents tracer signal to S/N ratio in its electromagnetic conversion characteristics, N presentation medium noise) height, and when producing in enormous quantities, can stably obtain coercive force.
The 2nd purpose of the present invention is to provide a kind of magnetic recording medium manufacture method, even under the lower situation of the matrix surface temperature of this method in film forming procedure, or matrix is not added under the situation of bias-voltage, still can form medium at an easy rate with high-coercive force.
Disclosure of an invention
Magnetic recording medium of the present invention is a flux reversal type magnetic recording medium, on its matrix surface, pass through metal lining, formation is by the ferromagnetism metal level of being made up of CoNiCr at least, the oxygen concentration of above-mentioned ferromagnetism metal level is below 100ppm (weight), it is characterized in that having the grain boundary layer that amorphous structure constitutes at the intergranule that forms the ferromagnetism metal level.
In addition, magnetic recording medium of the present invention is a flux reversal type magnetic recording medium, on its matrix surface, pass through metal lining, formation is by the ferromagnetism metal level of being made up of CoCrPt at least, the oxygen concentration of above-mentioned ferromagnetism metal level is below 100ppm (weight), it is characterized in that having the grain boundary layer that amorphous structure constitutes at the intergranule that forms the ferromagnetism metal level.
Another feature of above-mentioned magnetic recording medium is that above-mentioned grain boundary layer is nonmagnetic, and above-mentioned ferromagnetism metal level comprises the Ta as the 4th element.
The another of above-mentioned magnetic recording medium is characterised in that above-mentioned metal lining is Cr, and the film thickness of above-mentioned metal lining is in the scope of 5nm～30nm.
One being characterised in that again of above-mentioned magnetic recording medium, magnetic recording medium of the present invention is different with above-mentioned magnetic recording medium, and it forms above-mentioned ferromagnetism metal level not by metal lining on above-mentioned matrix surface.
The manufacture method of magnetic recording medium of the present invention relates to following manufacture method, the formation method of wherein above-mentioned metal lining and/or above-mentioned ferromagnetism metal level is a sputtering method, it is characterized in that the matrix surface temperature when forming above-mentioned metal lining and/or above-mentioned ferromagnetism metal level is 60 ℃～150 ℃.
Another feature of the manufacture method of above-mentioned magnetic recording medium is, when forming above-mentioned metal lining and/or above-mentioned ferromagnetism metal level, above-mentioned matrix except that the self-bias by plasma generation, is not applied electrical bias.
According to the described invention of claim 1, have the carrying out along its surface direction in the medium of magnetic recording of the ferromagnetism metal level formed by CoNiCr, owing to have the grain boundary layer that constitutes by amorphous structure at the intergranule that forms above-mentioned ferromagnetism metal level, so can obtain high coercive force and standard coercive force, and have good S/N ratio.
According to the described invention of claim 2, have the carrying out along its surface direction in the medium of magnetic recording of the ferromagnetism metal level formed by CoCrPt, owing to have the grain boundary layer that forms by amorphous structure at the intergranule that forms above-mentioned ferromagnetism metal level, so can obtain high coercive force and standard coercive force, and have good S/N ratio.
According to the described invention of claim 3, because grain boundary layer is nonmagnetic, so be the state that the zone of each intergranule of small magnet can prevent the magnetic confusion.Consequently, when carrying out magnetic recording, can reduce to become the transitional region of noise source by flux reversal.
According to the described invention of claim 4, because the ferromagnetism metal level contains the Ta as the 4th element, so can form bigger grain boundary layer zone.
According to the described invention of claim 5, because being Cr, metal lining forms, so can promote the formation of above-mentioned grain boundary layer.
According to the described invention of claim 6,, can further reduce the crystal grain of ferromagnetism metal level like this because the film thickness of metal lining is set in the scope of 5nm～30nm.Consequently, the media noise in the time of can reducing record regenerating more.
According to the described invention of claim 7, can obtain to have the magnetic recording medium of the good S/N ratio corresponding with the perpendicular magnetic recording picture recording.
According to the described invention of claim 8, because the film-forming temperature of magnetic recording medium can be lower, thus can reduce the gas flow of the indoor generation of film forming, and even can adopt the relatively poor matrix materials such as plastics of high temperature heating properties.
According to the described invention of claim 9, owing to matrix is not added except by the bias-voltage the self-bias of plasma generation, so the gas flow that takes place in the matrix atmosphere can reduce film forming the time.Can reduce the disengagements such as anchor clamps that film is used from fixing base in addition.
Below the embodiments of the present invention example is described.
Matrix
Matrix of the present invention for example can be enumerated aluminium, titanium and alloy thereof, silicon, and glass, carbon, pottery, plastics, resin and compound thereof, and the nonmagnetic film that lays foreign material by sputtering method, vapour deposition method, electrochemical plating etc. at these material surfaces carries out the surface applied processing.Preferably being laid in nonmagnetic film on the above-mentioned matrix surface can Yin Gaowen and magnetize, and has electric conductivity, is easy to carry out machine work etc., and this film has the skin hardness of appropriateness on the other hand.As the nonmagnetic film that satisfies above-mentioned condition, be good particularly with (Ni-P) film of making by sputtering method.
Be used for the occasion of disk, base shape adopts annular disk-shaped.Be provided with the matrix of the magnetosphere that will describe the back etc., promptly magnetic recording medium is an axle with the disc centre when carrying out magnetic recording and regeneration, is rotated and uses with the rotating speed such as 3600rpm.At this moment, magnetic head is crossed the height flight of magnetic recording medium superjacent air space with 0.1 μ m.Therefore, must be to the collimation on the surface flatness of matrix, inside and outside two surfaces, carry out suitable control along the flexibility and the surfaceness of matrix circumferencial direction.
In addition, the occasion of rotating at matrix/stopping, the surface of magnetic recording medium and magnetic head come in contact each other and slide (Contact Start Stop abbreviates CSS as).As the measure of dealing with above-mentioned situation, also on matrix surface, form the slight trace (texture) that is circular concentric sometimes.
Metal lining
Metal lining of the present invention for example can be enumerated Cr, Ti, W and alloy thereof.At this metal lining is the occasion of alloy, suggestion for example with the combination of V, Nb, Ta etc.Especially preferably Cr plays the segregation effect because its understands the ferromagnetism metal level that will describe the back.In addition, film build method adopts widely used sputtering method in a large amount of production, vapour deposition method etc.
The effect of above-mentioned metal lining is when the ferromagnetism metal level of being made up of the Co base is set thereon, promote the crystal growth of ferromagnetism metal level, so that make the direction of the easy magnetized axis of ferromagnetism metal level, promptly increase the coercive force of matrix place in-plane along plane, matrix place.
In the occasion of making the metal lining of forming by Cr by sputtering method, the gaseous tension the when factor of controlling its crystallinity comprises the surface configuration of matrix, surface state or surface temperature, film forming, be added on bias voltage on the matrix and formed film thickness etc. outward.Particularly, because the trend that the coercive force of ferromagnetism metal level has the film thickness with Cr to increase pro rata, so the Cr film thickness for example is set in the scope of 50nm～150nm and uses in the past.
Here, existing membrance casting condition (membrance casting condition of the present invention) refers to that the opposite pressure of film forming room is 10
-7(10
-9) torr, and during film forming the impurity concentration in the used Ar gas at (below the 100ppt, it is following to be preferably in 10ppb) more than the 1ppm.Impurity concentration in the used target is preferably in below the 150ppm when forming metal lining in addition.
In order to improve recording density, must reduce the suspension amount of the relative media surface of magnetic head.If above-mentioned Cr film thickness is bigger, then the surfaceness of medium also tends to increase.Therefore, best Cr thin film thickness, thus obtain high coercive force.
The ferromagnetism metal level
Ferromagnetism metal level of the present invention for example can be enumerated following two kinds.
The 1st kind is suitable for by metal lining it being arranged on occasion (i.e. the occasion of recording magnetic film in plane, matrix place) on the matrix surface, for example can enumerates CoNiCr, CoCrTa, CoCrPt, CoNiPt, CoNiCrTa, CoCrPtTa etc.
In the present invention, be fit to adopt following material system, this material means under existing membrance casting condition do not have the CoNiCr and the CoCrPt of the grain boundary layer of amorphous structure formation at intergranule.But,, then can confirm if adopt membrance casting condition of the present invention, even in following material system, still can further control, even this material means under existing membrance casting condition to grain boundary layer, other the material system (for example, CoCrTa and CoNiPt system) that also has several grain boundary layers.
Here, existing membrance casting condition (membrance casting condition of the present invention) refers to that the opposite pressure of film forming room is 10
-7(10
-9) torr, and during film forming the impurity concentration in the used Ar gas at (below the 100ppt, it is following to be preferably in 10ppb) more than the 1ppm.Impurity concentration in the used target is preferably in below the 30ppm when forming metal lining in addition.
Belonging in above-mentioned the 1st kind, because the CoNiCr price is lower, be not vulnerable to the influence of film forming atmosphere, in addition because the media noise of CoCrTa is lower, and CoPt based material inaccessible above coercive force of 1800Oe can obtain to adopt CoNiCr and CoCrTa to make the time, so preferably adopt above-mentioned material.
The problem of above-mentioned the 1st kind of required solution is following material and a manufacture method thereof of exploitation, and the cost of this material is lower, and media noise is less, can obtain higher coercive force, so that improve recording density, reduces manufacturing cost.
As the 2nd kind of occasion (being the occasion of perpendicular recording) that is suitable for directly it not being formed on the matrix surface, for example can enumerate CoCr, CoPt, CoCrTa etc. with magnetic film by metal lining.In addition, also can below above-mentioned ferromagnetism metal level, be provided as the soft magnetic metal layer of backing layer sometimes.
If adopt membrance casting condition of the present invention, then can confirm, even in following material system, still can further control, even this material means under existing membrance casting condition also have the material system of several grain boundary layers to grain boundary layer.
The problem of above-mentioned the 2nd kind of required solution is following material and a manufacture method of exploitation, even this material under the thin situation of the film thickness of ferromagnetism metal level, still can keep the high coercive force of the perpendicular direction in edge and film surface.
Flux reversal type magnetic recording medium
" flux reversal type magnetic recording medium " of the present invention has following two types, promptly on the face of above-mentioned ferromagnetism metal level, write down the medium (on its plane, place, carrying out the medium of magnetic recording) that magnetization is handled in mode with its keeping parallelism, and on above-mentioned face, write down the medium (perpendicular magnetic recording medium) that magnetization is handled in the mode perpendicular with it.
No matter any medium are self-evident, all must seek to write down magnetized miniaturization, so that improve recording density.Magnetize leaked magnetic flux amount when handling because above-mentioned miniaturization reduces to write down at every turn, thereby can reduce the output valve of the regenerated signal of magnetic head.Therefore, people wish that further the media noise that adjacent record magnetizes to be influenced is carried out in reduction.
The oxygen concentration of ferromagnetism metal level
Known, for example in the occasion of the CoNiCr film that adopts existing sputtering method to make, " oxygen concentration of ferromagnetism metal level " of the present invention is more than the 250ppm (weight).Preferably, promptly the coercive force of medium and the influence of media noise are analyzed the influence of the oxygen concentration of ferromagnetism metal level.
Above-mentioned existing sputtering method refers to film forming under the following conditions, and this condition is: the vacuum tightness that film forming room reached that is used to form the ferromagnetism metal level is 10
-7Torr, the impurity concentration when forming the ferromagnetism metal level in the used Ar gas is more than the 1ppm.
The oxygen concentration of metal lining
Known, adopting existing sputtering method to make the occasion of Cr film, " oxygen concentration of metal lining " of the present invention is more than the 250ppm (weight).Preferably to the influence of the oxygen concentration of metal lining,, the influence of the ferromagnetism metal level that forms on metal lining is analyzed promptly to the influence of the crystal growing process of the film thickness that depends on metal lining.
The implication of above-mentioned existing sputtering method is identical with explanation in above-mentioned " oxygen concentration of ferromagnetism metal level ".
The standard coercive force of ferromagnetism metal level (is expressed as Hc/Hk
Grain)
" the standardization coercive force of ferromagnetism metal level " of the present invention refers to the anisotropy field Hk of coercivity H and crystal grain
GrainRatio, the raising degree every magnetic of its expression crystal grain, foregoing is referring to document " Magnetization Reversal Mechanism Evaluated by Rotational Hysteresis LossAnalysis for the Thin Film Media " Migaku Takahashi, T.Shimatsu, M.Suekane, M.Miyamura, K.Yamaguchi and H.Yamasaki:IEEE TRANSACTIONS ONMAGUNETICS, VOL.28,1992, pp.3285 ".
When only limiting to the ferromagnetism metal level and be with Co be the material of base, the standard coercive force that adopts the ferromagnetism metal level that existing sputtering method makes is less than 0.3.According to the Stoner-Wohlfarth theory, fully every the occasion of magnetic, above-mentioned standard coercive force is 0.5 at crystal grain, and this numerical value is the coercitive higher limit of standard.
In addition, point out in " J.-G Zhu and H.N.Bertram:Journal of Applied Physics; VOL.63; 1988.pp3248 " document: the magnetic interaction of each intergranule of the high expression formation of the standard coercive force of so-called ferromagnetism metal level ferromagnetism metal level is lower, thereby can obtain high coercive force.
Here, coercivity H is meant the coercive force of the medium of being obtained by the magnetization curve that uses vibration sample type magnetometer (Variable SampleMagnetometer abbreviates VSM as) to measure.The anisotropy field Hk of crystal grain
GrainThe externally-applied magnetic field that refers to the rotational hysteresis loss complete obiteration that employing high sensitivity moment of torsion magnetometer is measured.In the occasion that on matrix surface, forms the magnetic recording medium of ferromagnetism metal level by metal lining, coercive force and anisotropy field refer in the value along film place in-plane mensuration, on matrix surface, form the occasion of the magnetic recording medium of ferromagnetism metal level, refer to the value of the perpendicular direction detection in plane, film place.
Aluminium alloy
Aluminium alloy of the present invention for example can be enumerated the alloy that aluminium and magnesium constitute.At present when being used for HD (hard disc), using maximum is with the material of aluminium alloy as matrix.Because application target is for carrying out magnetic recording, so preferably adopt the few alloy of metal oxide content.
In addition, adopt electrochemical plating or sputtering method that nonmagnetic (Ni-P) film is arranged on the aluminum alloy surface mostly.Its objective is the raising corrosion resistance, increase matrix surface hardness.Friction force in order to reduce to be produced when magnetic head slides on media surface is formed with the slight vestige (texture) that is circular concentric on the surface of above-mentioned (Ni-P) film.
Is the thin plateization that makes matrix with aluminium alloy as the occasion of matrix problem to be solved, reduces the surfaceness of matrix.At present, the ultimate value of the thickness of above-mentioned matrix is 0.5mm, and the ultimate value of surfaceness is 0.5nm.
Glass
Glass of the present invention for example can be enumerated the glass that glass surface is carried out intensive treatment such as ion doping, and carries out the structure that micritization handles and the glass that constitutes etc. by glass itself.It is above-mentioned that both all do not need to eliminate the measure of the shortcoming that is called " frangible " glass.
Because the skin hardness of glass is than the height of aluminium alloy, so its advantage is to be provided with (Ni-P) film etc.In addition, to the thin plateization of matrix, the flatness on matrix plane, aspects such as the heat-resisting quantity of matrix also are favourable.
But in order to make the magnetic film with high-coercive force, preferably the matrix surface temperature during film forming is higher, and can the limit to the matrix applying bias, film forming is carried out on the limit, so nonmagnetic layer often is set on glass surface.In addition, for the element that prevents to be harmful to invades the magnetic film from glass, sometimes nonmagnetic layer to be set.Perhaps, also on glass surface, form nonmagnetic layer sometimes with trickle concaveconvex shape in order to reduce the friction force that magnetic head slides and produced in the media.
Be that the problem of required solution is to take into account simultaneously the thin plateization of matrix in the occasion of matrix with glass, and prevent these two aspects of matrix breakdown.
Silicon
Silicon of the present invention specifically can adopt makes the product that circle obtains with in fact employed silicon chip in the semiconductor applications.
Same with glassy phase, the skin hardness of silicon is higher, and it can make the thickness of parent plate reduce, and in addition, the flatness of matrix surface is also higher, and the high-temperature stability of matrix is better, so be better than aluminium alloy aspect above-mentioned.In addition, because can be, so can expect to improve the controlled of the crystal growth that forms magnetic film thereon to the crystallization position of matrix surface to selecting with grating constant.Identical with aluminium alloy in addition, because matrix has electric conductivity, so can be to the matrix applying bias, because the H that emits from matrix inside
2Gas flows such as O are less, so film formation space is kept clean, therefore, it also is favourable adopting silicon aspect above-mentioned.
With glassy phase with, be that the problem of required solution is to take into account simultaneously the thin plateization of matrix in the occasion of matrix with silicon, and prevent this two aspect of matrix breakdown.
Sputtering method
" sputtering method " of the present invention for example can be enumerated at matrix when move in target the place ahead, film forming conveying type, and the film forming state type in the place ahead that matrix is fixed in target.Because the former output is higher, thus help making the medium of lower cost, because the latter can make sputtering particle that the incident angle of matrix is kept stable, so can make the good medium of recording.
Form metal lining and ferromagnetism metal level successively
" forming metal lining and ferromagnetism metal level successively " of the present invention refers to form after the metal lining on matrix surface, in during the formation ferromagnetism metal level on this metal lining surface, be not exposed in the high pressure atmosphere when gaseous tension when film forming is above.As everyone knows, after the surface of metal lining is exposed in the atmosphere, when forming the ferromagnetism metal level thereon, the coercive force of medium significantly descend (such as, do not expose to the open air: 1500Oe → expose to the open air: 500Oe is following).
Impurity and concentration thereof during film forming in the used Ar gas
" impurity during film forming in the used Ar gas " of the present invention for example can enumerate H
2O, O
2, CO
2, H
2, N
2, C
xH
y, H, C, O, CO etc.Particularly, the influence impurity that enters the oxygen amount in the film is defined as H
2O, O
2, CO
2, O, CO.The H that is contained in the used Ar gas when therefore, impurity concentration of the present invention refers to film forming
2O, O
2, CO
2, O, CO sum.
The cleaning of utilizing high-frequency sputtering to carry out
" cleaning of utilizing high-frequency sputtering to carry out " of the present invention for example can enumerate that (radio frequency: 13.56MHz) power supply applies the method for alternating voltage to the matrix that is positioned at the gaseous tension space that can discharge from RF.The characteristics of this method are also can be suitable for the occasion that matrix does not have electric conductivity.In general, the effect of cleaning comprises the tack of raising film on matrix.But after carrying out cleaning, the influence to the own character of film that forms on matrix surface has many not clear.
Impurity and concentration thereof when forming metal lining in the used Cr target
" impurity when forming metal lining in the used Cr target " of the present invention for example can enumerate Fe, Si, Al, C, O, N, H etc.Particularly, can conclude that the impurity that influences the oxygen amount in the film that enters is O.Therefore, impurity concentration of the present invention refers to the oxygen level in the Cr target used when forming metal lining.
Impurity and concentration thereof when forming the ferromagnetism metal level in the used target
" impurity when forming the ferromagnetism metal level in the used Co base target " of the present invention for example can enumerate Fe, Si, Al, C, O, N etc.Particularly, can conclude that the impurity that influences the oxygen amount in the film that enters is O.Therefore, impurity concentration of the present invention refers to the oxygen level in the target used when forming the ferromagnetism metal level.
On matrix, add negative bias
" adding negative bias on the matrix " of the present invention refers to when forming as the Cr counterdie of magnetic recording medium and magnetic film, to matrix external dc bias voltage.Known, if add suitable bias voltage, then increase the coercive force of medium.The effect of above-mentioned applying bias is known, promptly with only when making any one film the occasion of applying bias compare, the effect to the occasion of two layer applying bias is bigger simultaneously.
But the majority that applies of above-mentioned bias voltage is to act near the object of matrix, promptly on substrate support parts and the substrate holder.Consequently, can produce gas and dust near the space matrix, this gas and dust enter in the film in the film forming, are easy to generate the unsettled unfavorable condition of various membrane properties.
Also can produce following problem to the matrix applying bias in addition.
1. be not suitable for non-conductive body such as glass.
2. the saturation magnetic flux density of the magnetic film of Xing Chenging (Ms) reduces.
3. complicated mechanism must be set in film forming room inside.
4. the degree to the matrix applying bias changes easily, and consequently, magnetic characteristic is easy to generate partially
Difference.
Therefore, even be desirable to provide a kind of manufacture method that above-mentioned bias voltage also can obtain to meet the various membrane properties of index that do not add.
Be used to form the vacuum tightness that film forming room reached of metal lining and/or ferromagnetism metal level
" being used to form the vacuum tightness that film forming room reached of metal lining and/or ferromagnetism metal level " of the present invention changes with the difference of ferromagnetism metal layer material, is one of film forming factor of control coercive force numerical value.Particularly, think in the past, comprise the Co sill of Ta in the ferromagnetism metal level, the lower occasion of the above-mentioned vacuum tightness that reaches (such as, 5 * 10
-6The occasion that torr is above), above-mentioned coercive force is produced bigger influence.But, according to the present invention as can be known,, among CoNiCr and the CoCrPt, just can form the viewpoint of the grain boundary layer that constitutes by amorphous structure at intergranule even do not comprising the Co sill of To, the vacuum tightness that film forming room reached works.
Matrix surface temperature when forming metal lining and/or ferromagnetism metal level
" the matrix surface temperature when forming metal lining and/or ferromagnetism metal level " of the present invention is irrelevant with the material of ferromagnetism metal level, and it is one of film forming factor of control coercive force numerical value.In the scope that matrix is not caused damage, form film with higher surface temperature and can obtain higher coercive force.The damage of above-mentioned matrix refers to external change such as bending, expansion, crackle, or the interior change such as gas flow increase of magnetizing, producing.
But, generally must carry out certain heat treated by the chamber of film forming room or its front in order to realize higher matrix surface temperature.This heat treated can produce following rough sledding, promptly produces gas and dust near the space matrix, and this gas and dust can enter in the film in the film forming procedure, thereby makes the characteristic instability of various films.
In addition, higher matrix surface temperature also produces following problem.
1. the non magnetic NiP layer that is positioned on the NiP/Al matrix magnetizes.
2. matrix deforms.
3. for the lower matrix of temperature conductivitys such as glass, be difficult to improve, or keep substrate temperature.
Therefore, be desirable to provide a kind of above-mentioned heat treated of not carrying out, even or carry out lower temperature heat treated also can obtain to meet the method for making of the various membrane properties of index.
Matrix surface roughness: Ra
" matrix surface roughness " of the present invention specifically can be the average centerline roughness Ra under following occasion, and this occasion refers to along radial direction the disc matrix surface be measured.The TALYSTEP that analyzer adopts RANKTAYLORHOBSON company to make.
The occasion that begins to rotate from halted state at matrix, or occasion in contrast to this, magnetic recording medium contacts with head surface, and produces slide (Contact Start Stop abbreviates CSS as).
At this moment, for the absorption that suppresses magnetic head and the rising of friction factor, preferably the value of Ra is bigger.On the other hand, reach the occasion of maximum speed at matrix, owing to must guarantee the spacing between magnetic recording medium and the magnetic head, i.e. the suspension amount of magnetic head, preferably the value of Ra is less.
Therefore, technical conditions be reach for the above reasons, the surfaceness of matrix, maximal value and the minimum value of Ra suitably determined the matrix requirement.Such as, be the occasion of 2 microinchs in the suspension amount of magnetic head, Ra=6nm～8nm.
But,, must further reduce head gimbal amount (when carrying out the record regenerating action, magnetic head leaves the distance on magnetic recording medium surface) in order further to realize high density recording.In order to satisfy above-mentioned needs, further make the magnetic recording medium surface more planarization be very important.For the above reasons, wish further to reduce the surfaceness of matrix.
Therefore, even be desirable to provide the method for making that a kind of surfaceness that further reduces matrix also can obtain to meet the various membrane properties of index.
Texture processing
" texture processing " of the present invention for example can enumerate mechanical milling method, chemical corrosion method, the method for additional physics embossed film etc.Particularly, be the occasion that makes aluminium alloy with the most use at the matrix of magnetic recording medium, mechanical milling method is adopted in above-mentioned processing.Such as, have the surface is bonded with the grinding abrasive band of grinding with particle presses on the matrix of rotation, (Ni-P) film that is arranged on the aluminum alloy surface to be ground, formation is the method for the slight vestige of circular concentric.Said method makes grinding with particle dissociate to get off from the abrasive band situation of use in addition.
But, because the reason described in above-mentioned " surfaceness of matrix ",, or form the method for making that slighter vestige also can obtain to meet the various membrane properties of index even people are desirable to provide and are not a kind ofly carrying out above-mentioned texture processing.
The combined electrolysis milled processed
" combined electrolysis milled processed " of the present invention for example can enumerate following processing, promptly is provided with the oxidation passive state film of chromium oxide as product on the inwall of used vacuum chamber when forming magnetic film etc.In this occasion,, be good for example with SU316L etc. as the material that constitutes the vacuum chamber inwall.Because above-mentioned processing can reduce the O that the vacuum chamber inwall produces
2, H
2The discharge capacity of O can further reduce the oxygen amount in the film that enters made like this.
(model is ILC 3013 to the magnetic controlled tube sputtering apparatus of producing in Ah being of the present invention Shandong Bagong department (ァ ネ Le バ): the static opposed type of loadlock compact form), all vacuum chamber (charging/discharge chambers, film forming room, clean room) inwall all carries out above-mentioned processing.
Brief description of drawings
Fig. 1 is the photo of transmission electron microscope (TEM) of the sample 1 of embodiment 1;
Fig. 2 is the photo of transmission electron microscope (TEM) of the sample 2 of embodiment 1;
Fig. 3 is that expression uses EDS the intergranule of the sample 1 of embodiment 1 to be carried out composition analysis result's curve map;
Fig. 4 is the diagrammatic cross-section of reading the field structure of monolithic devices thin-film head, and this thin-film head is used to estimate the electromagnetic conversion characteristics of the magnetic recording medium of embodiment 1;
Fig. 5 is the film thickness of the metal lining that is made of Cr of expression embodiment 4 and the coercitive graph of relation of made medium;
Fig. 6 is the graph of relation of the noise of the film thickness of the metal lining that is made of Cr of expression embodiment 4 and made medium;
The coercitive graph of relation of matrix surface temperature when Fig. 7 is the expression formation metal lining of embodiment 5 and ferromagnetism metal level and made medium;
The graph of relation of matrix surface temperature when Fig. 8 is the expression formation metal lining of embodiment 5 and ferromagnetism metal level and made media surface roughness Ra;
Fig. 9 is the coercitive graph of relation that is illustrated in the negative bias values that adds on the matrix of embodiment 6 and made medium;
Figure 10 is the synoptic diagram of explanation magnetic recording medium.
The explanation of symbol
1 matrix
2 Al substrates
3 non magnetic (Ni-P) layer
4 Cr linings
5 ferromagnetism metal levels
6 protective seams
41 top magnetic sheets
42 bottom magnetic sheets
43 write coils
44 write gap length
45 guard shields
46 MR component parts
47 read gap length
Implement best mode of the present invention
Below by embodiment the present invention is carried out more specific description, but the present invention is not limited to these enforcement.
The crystal grain that present embodiment represents to form the ferromagnetism metal level keeps the effect of the grain boundary layer that amorphous structure forms at least at intergranule.
In order to confirm above-mentioned effect, change the vacuum tightness that film forming room reached that forms metal lining.The vacuum tightness that film forming room reached that forms metal lining is set at 10
-9Torr and 10
-7Torr.
At this moment, the impurity concentration that is contained in the Ar gas when forming ferromagnetism metal level and metal lining remains on 10pbb, and the vacuum tightness that film forming room reached that is used to form the ferromagnetism metal level remains on 10
-9Torr.
According to present embodiment; the sputter equipment that is used to make medium is that (model is ILC 3013 to the magnetic controlled tube sputtering apparatus made of A Nailu crust (ァ ネ Le バ) company: the static opposed type of loadlock compact form); inwall to all vacuum chambers (charging/discharge chamber, (clean room of holding concurrently), the 1st film forming room (formation metal lining), the 2nd film forming room (forming the ferromagnetism metal level), the 3rd film forming room (formation protective seam)) all carries out the combined electrolysis milled processed.Membrance casting condition when table 1 has been listed the magnetic recording medium of making present embodiment.
Table 1
| | Setting value | |
| 1. the surface configuration of the diameter of | The Al-Mg alloy (has film thickness and is (Ni-P) electroplating film) 89mm of 10 μ m, disc-shape has texture, Ra＜ | |
| 4. the pressure of the impurity concentration 6.Ar gas in the vacuum that reaches (torr) the 5.Ar gas (milli torr) 7. the maintenance temperature of matrix surface (℃) 8. target material (%) 9. target diameter (inch) 10. on spacing (mm) 12. targets of impurity concentration (ppm) 11. targets in the target and matrix added Dc bias (V) 14. film thicknesses of making (nm) on the matrix when adding power supply (W) 13. film forming | 10 -7Or 10 -9(the 1st film forming room) 5 * 10 -9(except that the 1st film forming room) 10ppb (each chamber is all identical) 2 (each chamber is all identical) 230 (each chamber is all identical) Cr, Co 62.5Ni 30Cr 7.5C 6 120 (Cr), 20 (CoNiCr), 35 (Cr, CoNiCr, C) direct current 200 (Cr, CoNiCr) direct current 400 (C) 200 (Cr, CoNiCr) 0 (C) 50 (Cr), 15 (CoNiCr), 10 (C) |
Manufacture method to the magnetic recording medium in the present embodiment describes in order below.Below bracketed sequence number represent the order of said method.
(1) the following discoidal aluminium alloy base plate of matrix adopting, its inside/outside directly is 25mm/89mm, thickness is 1.27mm.By electrochemical plating (Ni-P) film that thickness is 10 μ m is set on the aluminium alloy base plate surface.Process the slight trace (texture) that is circular concentric with mechanical means on this (Ni-P) film surface, the average centerline roughness Ra during along the disc radius scanning direction in the matrix surface roughness is less than 1nm.
(2) before the film forming that will describe in the back, this matrix is carried out cleaning treatment, and it is carried out dried by hot blast etc. by machinery and chemical method.
(3) will place through the above-mentioned matrix of dried on the following substrate holder, this support is arranged in the feed space in the sputter equipment, is made of aluminium.By vacuum pumping hardware feed space inside is vacuumized, treat that vacuum tightness reaches 3 * 10
-9Behind the torr, with infrared lamp matrix is carried out 250 ℃, 5 minutes heat treated.
(4) above-mentioned substrate holder is moved on to the 1st film forming room that is used to make the Cr film from feed space.To the matrix heating after moving, make its temperature remain on 250 ℃ with infrared lamp.But, in advance the 1st film forming room is vacuumized, make its vacuum tightness reach 1 * 10
-7Torr, or 3 * 10
-9Torr.In addition, after above-mentioned substrate holder moves, will close at the gate-type valve between feed space and the 1st film forming room.Impurity concentration in the used Cr target is 120ppm.
(5) Ar gas is injected the 1st film forming room, make the gaseous tension in the 1st film forming room reach 2 milli torrs.The impurity concentration stuck-at-0ppb that contains in the used Ar gas.
(6) apply voltage from direct supply to the Cr target, its power is 200W, produces plasma.Consequently, the Cr target is splashed, forming film thickness on the matrix surface that is positioned at the relative position that parallels with target is the Cr layer of 50nm.
(7) after forming the Cr layer, above-mentioned substrate holder is moved on to the 2nd film forming room that is used for making the CoNiCr layer from the 1st film forming room.After moving, also matrix is heated with infrared lamp, make its temperature remain on 250 ℃.But, vacuum tightness that the 2nd film forming room reached is realized by the mode of change condition.This imposes a condition and is meant above-mentioned chamber vacuumized and makes its vacuum tightness reach 3 * 10
-9The occasion of torr and above-mentioned chamber vacuumized make its vacuum tightness reach 3 * 10
-7These two conditions of the occasion of torr.In addition, after above-mentioned substrate holder moves, will close at the gate-type valve between the 1st film forming room and the 2nd film forming room.The target composition that uses is: Co62.5% (at), and Ni30% (at), Cr7.5% (at), the concentration of impurity is 20ppm in the target.
(8) Ar gas is injected the 2nd film forming room, make the gaseous tension in the 2nd film forming room reach 2 milli torrs.The impurity concentration stuck-at-0ppb that contains in the used Ar gas.
(9) from direct supply the CoNiCr target is applied voltage, its power is 200W, produces plasma.It is as a result the time, and the CoNiCr target splashes, be positioned at relative position that target parallels on the matrix surface that has the Cr layer on to form film thickness be the CoNiCr layer of 15nm.
(10) after forming the CoNiCr layer, above-mentioned substrate holder is moved on to the 3rd film forming room that is used for making the C film from the 2nd film forming room.After moving, matrix is heated equally, make its temperature remain on 250 ℃ with infrared lamp.But, in advance the 3rd film forming room is vacuumized, make its vacuum tightness reach 3 * 10
-9Torr after above-mentioned substrate holder moves, will be closed at the gate-type valve between the 2nd film forming room and the 3rd film forming room.
(11) Ar gas is injected the 3rd film forming room, make the gaseous tension in the 3rd film forming room reach 2 milli torrs.The impurity concentration stuck-at-0ppb that contains in the used Ar gas.
(12) from direct supply the C target is applied voltage, its power is 400W, produces plasma.It is as a result the time, and the C target splashes, be positioned at relative position that target parallels on the matrix surface that has CoNiCr layer/Cr layer on to form film thickness be the C layer of 10nm.
(13) after forming the C layer, above-mentioned substrate holder is moved on to the discharge chamber from the 3rd film forming room.Afterwards, with N
2Gas injects in the discharge chamber, reach atmospheric pressure after, take out matrix.By above-mentioned operation (1)～(12), make layer structure and be: the magnetic recording medium of C/CoNiCr/Cr/NiP/Al.
In addition, target adopts the material that can suppress impurity as far as possible.Impurity in the target that formation Cr uses is: Fe:88, Si:34, Al:10, C:60, O:120, N:60, H:1.1 (ppm (weight)).In addition, the composition that forms the target that the ferromagnetism metal level uses is: Ni:29.2% (at), Cr:7.3% (at), all the other are Co, and impurity is: Fe:27, Si＜10, Al＜10, C:30, O:20, N＞10 (ppm (weight)).
Fig. 1 and Fig. 2 are the photos of the transmission electron microscope (TEM) of the ferromagnetism metal level made.Fig. 1 and Fig. 2 are illustrated in the vacuum tightness occasion inequality that is reached in preceding the 2nd film forming room of film forming, and Fig. 1 is 3 * 10
-9The occasion of torr (sample 1), Fig. 2 is 1 * 10
-7The occasion of torr (sample 2).
The observation condition of following table 2 expression TEM.
Table 2
| |
| The TEM that tem |
Confirm that the oxygen concentration that contains in the ferromagnetism metal level in above-mentioned 2 kinds of samples is all below 100ppm (weight).Above-mentioned oxygen concentration is measured by secondary ion mass spectrometry instrument (SIMS:Secondary IonMass Spectrometer).
But from the TEM photo as can be known, in sample 1 and 2, the state of intergranule is different.That is to say in the occasion of sample 1 (Fig. 1), to have the grain boundary layer that amorphous structure constitutes at the intergranule that forms the ferromagnetism metal level, relative therewith, in the occasion of sample 2 (Fig. 2), can not confirm has the grain boundary layer that is equivalent in the sample 1.
Fig. 3 is for carrying out the result of composition analysis to 2 intergranules in the sample 1 (Fig. 1) by energy dispersion type X ray spectrophotometer (EDS:Energy Dispersive X-ray Spectroscopy).Near the composition that (zone 1 and 3) approximate target is formed the center of crystal grain.But, can see that the Cr concentration in (zone 2) is high significantly near the crystal grain layer, is non magnetic on alloy composition.
Below the magnetic characteristic of magnetic recording medium and the various condition determinations of electromagnetic conversion characteristics are described.Magnetic measurement is measured by vibration sample type magnetometer (VSM) and moment of torsion magnetometer.Detailed condition determination is as shown in table 3.
Table 3
| Project | |
| Shape | |
| 2. magnetic fields of | On the base sheet surface of φ 8mm, disc-shape, carry out in the shape face that film forming forms, and at the circumferencial direction 15kOe of the matrix of disc- |
| Shape | |
| 2. magnetic fields of moment of | The relative face of shape (0 degree) that carries out film forming formation on the base sheet surface of φ 8mm, disc-shape revolves three-sixth turn and applies magnetic field 10kOe |
In addition, electromagnetic conversion characteristics is to use following magnetic head to measure under the condition determination of table 4, this magnetic head refers to the monolithic devices thin-film head that writes, reads shown in Figure 4 (write finger inductive head (InductiveHead), read finger reluctance head (Mgnetic Resistance Head)).
Table 4
Below table 5 be the magnetic characteristic of the magnetic recording medium under the condition that draws from Fig. 1 and Fig. 2, made and the result of electromagnetic conversion characteristics.
Table 5
| The | Sample | 1 | |
| The vacuum tightness (torr) that is reached during the lining film forming | ????10 -9 | ?????10 -7 | |
| The grain boundary layer that has or not amorphous structure to constitute | Have | Do not have | |
| Coercive force (Oe) | ?????2450 | ?????1050 | |
| ???????????Hc/Hk | ?????0.35 | ?????0.18 | |
| ??????????S/N(dB) | ?????23.6 | ?????14.0 |
According to the result of table 5 as can be known, compare with sample 2, magnetic characteristic in the sample 1 and electromagnetic conversion characteristics are all better.Therefore, can conclude that following medium can become the magnetic recording medium that can realize higher recording density, these medium refer to have the grain boundary layer that amorphous structure forms at the intergranule that forms the ferromagnetism metal level.
The difference of present embodiment and the 1st embodiment is ferromagnetism metal level CoCrPt replaced C oNiCr.The composition of the target that formation CoCrPt film is used is: Co
75-Cr
13-Pt
12(at%).
Other aspect is identical with embodiment's 1.
Equally in the present embodiment, also confirmed to depend on result's (table 6) of the vacuum tightness that the film forming in the 1st film forming room that is used to form metal lining is reached before.
Table 6
| The | Sample | 3 | |
| Back-pressure during the lining film forming (torr) | ????10 -9 | ????10 -7 | |
| The grain boundary layer that has or not amorphous structure to constitute | Have | Do not have | |
| Coercive force (Oe) | ????3400 | ????1500 | |
| ????????????Hc/Hk | ????0.37 | ????0.20 | |
| ???????????S/N(dB) | ????25.0 | ????17.0 |
According to the result of table 6 as can be known, compare with sample 4, the magnetic characteristic and the electromagnetic conversion characteristics of sample 3 are better.Therefore, can conclude that following medium are the magnetic recording mediums that can adapt to higher recording density,, also have the grain boundary layer that amorphous structure forms at the intergranule that forms the ferromagnetism metal level even these medium are the occasion of CoCrPt at the ferromagnetism metal level.
The difference of present embodiment and embodiment 1 is ferromagnetism metal level CoNiCrTaCoCrPtTa replaced C oNiCr.The composition that is used to form the target of each ferromagnetism metal level is: Co
82.5-Ni
26-Cr
7.5-Ta
4(at%), Co
75.5-Cr
10.5-Ta
4-Pt
10(at%).
Other aspect is identical with embodiment's 1.
Occasion at present embodiment confirms, with the 1st film forming room that forms metal lining in film forming before the vacuum tightness (10 that reached
-7The occasion of torr and 10
-9The occasion of torr) under the irrelevant situation, no matter in any ferromagnetism metal layer material, all has grain boundary layer.But, the vacuum tightness that this reached hour, the area of grain boundary layer big (table 7) then.
Table 7
| The | Sample | 5 | | Sample 7 | Sample 8 |
| Magnetic layer material | ???????CoNiCrPt | ???????CoCrPtTa | |||
| Back-pressure when forming the lining film | ???10 -9Torr | ??10 -7Torr | ???10 -9Torr | ??10 -7Torr | |
| The grain boundary layer that has or not amorphous structure to form | Have | Have | Have | Have | |
| The area of the grain boundary layer that amorphous structure forms | Greatly | Little | Greatly | Little | |
| Coercive force (Oe) | ????2640 | ???1270 | ????3350 | ????1600 | |
| ????????????Hc/Hk | ????0.36 | ???0.22 | ????0.37 | ????0.26 | |
| ???????????S/N(dB) | ????25.3 | ????20.3 | ?????26.1 | ?????21.5 | |
As can be known from the results of Table 7, compare with sample 6, the magnetic characteristic and the electromagnetic conversion characteristics of sample 5 are better, compare with sample 8, and the magnetic characteristic and the electromagnetic conversion characteristics of sample 7 are better.Therefore, can conclude, following medium are the magnetic recording mediums that can fit higher recording density, even these medium contain the occasion of Ta element in the alloying component that forms the ferromagnetism metal level, also has the grain boundary layer that the bigger amorphous structure of its area forms at the intergranule that forms the ferromagnetism metal level.
The difference of present embodiment and embodiment 1 is that the film thickness that changes metal lining in the scope of 0～100nm carries out film forming.
In addition, following occasion is analyzed, this occasion comprises that the vacuum tightness that was reached that is used for the 1st film forming room (being used to form metal lining) and the 2nd film forming room (being used to form the ferromagnetism metal level) is 10 before film forming
-9The occasion of torr (condition a), and be 10
-7The occasion of torr (condition b).
Other aspect is identical with embodiment's 1.
Fig. 5 represents the relation between the coercive force of the film thickness of the metal lining that formed by Cr and made medium.Ordinate is represented the coercitive numerical value along the circumferencial direction of the matrix of disc-shape, the symbol zero expression condition a among the figure, symbol ● expression condition b.
As can be seen from Figure 5, when the film thickness of Cr metal lining is 2.5nm when above, corresponding to the coercive force of the medium of condition a greater than maximal value corresponding to the coercive force of the medium of condition b.In addition, preferably the film thickness of Cr metal lining can obtain the above high coercive force of 2000Oe more than 5nm.
Fig. 6 represents the relation between the noise of the film thickness of the metal lining that formed by Cr and made medium.Symbol zero expression condition a among the figure, symbol ● the minimum value of expression condition b.The assay method of the media noise of present embodiment is identical with the condition determination of embodiment 1.Only the film thickness of Cr layer changes in the scope of 1nm～100nm, and other condition is constant.
As can be seen from Figure 6, when the film thickness of Cr metal lining is 100nm when following, corresponding to the noise of the medium of condition b less than minimum value corresponding to the noise of the medium of condition b.In addition, preferably the film thickness of Cr metal lining can be realized the low media noise below 10% below 30nm.
Therefore, be formed with the occasion of the grain boundary layer that amorphous structure constitutes, promptly in the occasion of condition a at the intergranule that forms the ferromagnetism metal level, in the scope of film thickness at 2.5nm～100nm of the metal lining that forms by Cr, b compares with condition, and coercive force increases, or the noise of medium reduces.In addition, preferably the film thickness of the metal lining that is formed by Cr is limited in the scope of 5nm～30nm, and b compares with condition, can obtain higher coercive force, and lower media noise.
The difference of present embodiment and embodiment 1 is that the matrix surface temperature when forming metal lining and ferromagnetism metal level changes carries out film forming in 25 ℃～250 ℃ scope.
In addition, following occasion is analyzed, this occasion comprises that the vacuum tightness that was reached that is used for the 1st film forming room (being used to form metal lining) and the 2nd film forming room (being used to form the ferromagnetism metal level) is 10 before film forming
-9The occasion of torr (condition c), and be 10
-7The occasion of torr (condition d).
Other aspect is identical with embodiment's 1.
Relation when Fig. 7 represents to form metal lining and ferromagnetism metal level between the coercive force of matrix surface temperature and made medium.Ordinate is represented the coercive force numerical value along the circumferencial direction of discoid matrix, the symbol zero expression condition c among the figure, symbol ● expression condition d.
Relation between matrix surface temperature when Fig. 8 represents formation metal lining among the condition c and ferromagnetism metal level and the surface roughness Ra of the medium that form.
As can be seen from Figure 7, when the matrix surface temperature increases, with the situation of conditional independence under, the coercive force trend increases.In addition, also know from Fig. 7, when above-mentioned surface temperature more than 60 ℃ the time, the coercive force of the coercive force greater than condition d of condition c.
As shown in Figure 8, when the matrix surface temperature more than 150 ℃ the time, the surface roughness Ra of medium sharply increases.When the suspension amount of carrying out the above-mentioned relatively medium of magnetic head reaches the magnetic head come-up test of 15nm, then repeatedly find the phenomenon of magnetic head bump media surface, i.e. head crash.
But head crash then can not take place 60 ℃～150 ℃ occasion in the matrix surface temperature when forming metal lining or ferromagnetism metal level.
Therefore as can be known, the occasion that does not have the grain boundary layer of amorphous structure formation at the intergranule that forms the ferromagnetism metal level, promptly in order to realize the coercive force higher than condition d simultaneously, the matrix surface temperature when forming metal lining and/or ferromagnetism metal level must be in 60 ℃～150 ℃ scope.
In addition, the low temperature that can in the past can not obtain high-coercive force is made medium, therefore also can use for example matrixes such as pottery, plastics, resin, these matrixes to refer to because heating is former thereby can not use from matrix generation gas etc.
In the above-described embodiments,, also confirm, the occasion of nonmagnetic layer is set on matrix surface though matrix adopting is the Ni-P/Al substrate, such as, adopt the occasion of the glass substrate that forms Ni-P, Ti, C etc. in its surface etc., also be effective.
The difference of present embodiment and embodiment 1 is, when forming metal lining and ferromagnetism metal level, be added on outward negative bias values on the matrix 0～-change in the scope of 500V and carry out film forming.
In addition, following occasion is analyzed, this occasion comprises that the vacuum tightness that was reached that is used for the 1st film forming room (being used to form metal lining) and the 2nd film forming room (being used to form the ferromagnetism metal level) is 10 before film forming
-9The occasion of torr (condition e), and be 10
-7The occasion of torr (condition f).
Other aspect is identical with embodiment's 1.
Fig. 9 represents the relation between the outer coercive force that is added on negative bias values on the matrix and made medium.Ordinate is represented the coercive force numerical value along the circumferencial direction of disc-shape matrix, the symbol zero expression condition e among the figure, symbol ● expression condition f.
As can be seen from Figure 9, if the negative bias values that is added on the matrix increases, then do not exist with ... condition outward, the coercive force trend strengthens.In addition, from Fig. 9, also can confirm, with condition f obtain maximum coercitive occasion (applying bias=-300V) compare, be that coercive force in 0 the occasion is bigger at the applying bias of condition e.
Can confirm also that in addition the occasion that applying bias changes on the matrix when forming metal lining or ferromagnetism metal level also has identical tendency.
Therefore can conclude, at the intergranule that forms the ferromagnetism metal level, occasion with grain boundary layer of amorphous structure formation, promptly in the occasion of condition e, when forming metal lining and/or ferromagnetism metal level, except that self-bias, even, also can form the magnetic recording medium that has high-coercive force than condition f not to the matrix applying electrical bias by plasma generation.
Consequently, can prevent the rough sledding that produces by applying bias, that is: 1. near matrix (substrate support parts and substrate holder) produce gas and dust, 2. can not be applicable to non-conductive body such as glass, 3. the saturation magnetic flux density of formed magnetic film (Ms) reduces, 4. complicated mechanism must be set in film forming room, and 5. the bias value that adds on the matrix is easy to generate variation; Its result can avoid magnetic characteristic to be easy to generate problems such as deviation.
Embodiment 7
The difference of present embodiment and embodiment 1 is, not by metal lining, directly forms the ferromagnetism metal level on matrix surface.In addition, use Co as the ferromagnetism metal level
85Cr
15(at%).
Identical among other aspect and the embodiment 1.Its result analyzes the coercive force of the perpendicular direction in edge and magnetic recording medium surface.Can confirm, with the vacuum tightness that film forming room reached that is used to form the ferromagnetism metal level be 10
-7The occasion of torr is compared, and is 10 in above-mentioned vacuum tightness
-9The occasion of torr has higher coercive force.In addition we know road forms the area of the grain boundary layer that the amorphous structure of the intergranule of ferromagnetism metal level constitutes, and vacuum tightness is 10
-9The occasion of torr is 10 than vacuum tightness
-7The occasion of torr is bigger.
Industrial applicibility
The invention provides a kind of following magnetic recording medium, this magnetic recording medium relates to the medium that carry out magnetic recording in its plane, these medium have when producing in enormous quantities the ferromagnetism metal level that CoNiCr alloy magnetic film or CoCrPt alloy magnetic film by good stability consist of, its coercivity is higher, and the S/N ratio of electromagnetic conversion characteristics (S represents tracer signal, N presentation medium noise) is good.
In addition, the invention provides following magnetic recording medium, it relates to the perpendicular magnetic recording medium of the ferromagnetism metal level that is made of CoCr alloy magnetic film, and this magnetic recording medium also has high coercivity.
The present invention can provide a kind of following manufacture method in addition, even the method is in the lower situation of the matrix surface temperature of film forming procedure, or not in the situation of external biasing voltage on the matrix, still be easy to form and have high coercivity, and has the magnetic recording medium of good S/N ratio.
Claims (9)
1. magnetic recording medium, this magnetic recording medium is the flux reversal type, on its matrix surface, pass through metal lining, form the ferromagnetism metal level that constitutes by CoNiCr at least, the oxygen concentration of above-mentioned ferromagnetism metal level is below 100ppm (weight), it is characterized in that having the grain boundary layer that amorphous structure constitutes at the intergranule that forms the ferromagnetism metal level.
2. magnetic recording medium, this magnetic recording medium is the flux reversal type, on its matrix surface, pass through metal lining, form the ferromagnetism metal level that constitutes by CoCrPt at least, the oxygen concentration of above-mentioned ferromagnetism metal level is below 100ppm (weight), it is characterized in that having the grain boundary layer that amorphous structure constitutes at the intergranule that forms the ferromagnetism metal level.
3. magnetic recording medium according to claim 1 and 2 is characterized in that above-mentioned grain boundary layer is non magnetic.
4. according to any one described magnetic recording medium in the claim 1～3, it is characterized in that above-mentioned ferromagnetism metal level comprises the Ta as the 4th element.
5. according to any one described magnetic recording medium in the claim 1～4, it is characterized in that above-mentioned metal lining is Cr.
6. according to any one described magnetic recording medium in the claim 1～5, it is characterized in that the film thickness of above-mentioned metal lining is 5nm～30nm.
7. any one described magnetic recording medium in the claim 1～4 is characterized in that, by metal lining, forms above-mentioned ferromagnetism metal level on above-mentioned matrix surface.
8. the manufacture method of any one described magnetic recording medium in the claim 1～7, wherein, the formation method of above-mentioned metal lining and/or above-mentioned ferromagnetism metal level is a sputtering method, it is characterized in that the matrix surface temperature when forming above-mentioned metal lining and/or above-mentioned ferromagnetism metal level is 60 ℃～150 ℃.
9. the manufacture method of any one described magnetic recording medium in the claim 1～8 is characterized in that, when forming above-mentioned metal lining and/or above-mentioned ferromagnetism metal level, to above-mentioned matrix except that self-bias by plasma generation, applying electrical bias not.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95197757 CN1178025A (en) | 1995-03-08 | 1995-03-08 | Magnetic recording medium and method of manufacturing same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95197757 CN1178025A (en) | 1995-03-08 | 1995-03-08 | Magnetic recording medium and method of manufacturing same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1178025A true CN1178025A (en) | 1998-04-01 |
Family
ID=5083330
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 95197757 Pending CN1178025A (en) | 1995-03-08 | 1995-03-08 | Magnetic recording medium and method of manufacturing same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1178025A (en) |
-
1995
- 1995-03-08 CN CN 95197757 patent/CN1178025A/en active Pending
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