JPS5860427A - Vertical magnetic recording media - Google Patents

Abstract

PURPOSE:To obtain a vertical magnetic recording medium having high quality and efficiency, by forming a polymerized thin film by glow discharge on a nonmagnetic substrate and providing a Co(alloy) magnetic layer in constitution of hexagonal denseness having vertically magnetic anisotropy in a vertical direction to the substrate on this thin film. CONSTITUTION:On a rigid substrate such as glass, alumite and Si wafer or a nonmagnetic substrate 8 of a soft substrate etc. such as polyimide and polyethylene terephthalate, after the inside of a vacuum device 1 is evacuated to >=10<-5>, a gaseous org. compound of an org. silicone compound such as pentamethylcyclopentasiloxane or a fluorine compound such as tetrafluoroethylene is supplied from an introducing opening 3 and is dispersed from a porous ring 4 for dispersion and is plasma-polymerized by applying high frequency high voltage to upper and lower electrodes 6 to form a thin film. A magnetic film is formed on this thin film by sputtering Co or Co group alloy having vertically magnetic anisotropy and orientating C axis in constitution of hexagonal denseness vertically on the surface of the substrate 8. By this way, a magnetic recording medium of high quality in which the magnetic film is not stripped off etc. is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high quality and high performance perpendicular magnetic recording medium.

Conventional perpendicular magnetic recording media are made of silica, glass, or quartz on a soft bimolecular film substrate such as polyimide or polyethylene terephthalate.

Vycor, anodized anodized aluminum alloy.

Aluminum alloy, brass, stainless steel, alumina sintered body.

Cobalt-chromium with full perpendicular magnetic anisotropy on a hard substrate such as a single crystal Si wafer.

It is manufactured by a method in which cobalt-rhenium is formed by a sputtering method or vapor layer method, or a method in which a permalloy layer is formed as a soft magnetic layer and a magnetic film having one-layer magnetic anisotropy is formed after that. 〇 With soft substrates, thermal deformation of the substrate occurs when forming a magnetic film by sputtering or vapor deposition, so it is difficult to create the tiny head float that is required to obtain the full recording density.
In reality, there was no advantage to using the head in a state where it was in full contact, and the disadvantage was that the media and head were subject to severe wear.

In addition, the hard substrate may be thermally deformed during the formation of the magnetic film, and even after polishing, the surface strength is 40crn, which is about 500A.
It can be obtained in valleys over a large area about the same as the diameter, which is necessary to obtain a recording density! It has the advantage of being able to maintain the floating or contact state of a magnetic head of 1500 A or less. However, when a hard substrate is used, unlike a flexible molecular substrate, there is a drawback that head crashes are likely to occur due to stress concentration when the magnetic head contacts the magnetic medium. The adhesion force is often weak, and there is a drawback that the entire underlayer of 'l''i-?Cr must be formed in order to prevent the magnetic film from peeling off.

[-In addition, the perpendicular magnetic H-pyromagnetic recording medium has a large close-packed structure Co
It is necessary to align the C axis of the -Cr crystal, which has a large crystal magnetic anisotropy, in a direction perpendicular to the substrate. As a result of detailed investigation of the effect of substrates on C-axis orientation, the inventors found that hard substrates (e.g. Does the C-axis orientation of a laminated substrate or anodized aluminum (aluminium-coated substrate) significantly decrease? I found it. Furthermore, when using a hard substrate, the film adhesion strength can be increased to 6/1 to -1, and the layer can be formed using a sputtering method or an evaporation method to form a violet underlayer. It has been found that when used, even such surface roughness on the order of micro-crystalline grains of the underlayer and micro-heterogeneity originating from the polycrystalline underlayer can be completely reduced in the C-axis orientation. This causes an unavoidable problem of low -F C-axis orientation even in hard forest materials that are normally used as substrates for sharp-surfaced M-grills.

In order to eliminate all of the seven drawbacks of the present invention, a thin film layer of plasma of a scum-like organic compound is formed on a non-magnetic substrate using low discharge, and it also has perpendicular magnetic anisotropy thereon. It is characterized by forming a cobalt-based or cobalt-based alloy magnetic film, and its purpose is to cure perpendicular magnetic anisotropy without being affected by the material of the substrate, and to provide excellent head crash resistance. Figure 1 shows an example of an apparatus for forming a plasma-combined thin film on a non-magnetic substrate by glow discharge using a gaseous organic compound. The inside of the Pel jar 1 is evacuated by a vacuum pump 2, and the dried scum is introduced into the Pel jar from the inlet 3 through the entire porous link 4. Glow discharge is performed between the upper electrode 5 and the lower mold &6 by applying a high voltage to the upper electrode 5 and the lower mold &6 using the entire high frequency power supply 7. The substrate 8 is fixed to the upper part of the electrode 6 in the claw.An example of a method for forming a plasma polymerized film by glow discharge is described below after reducing the vacuum level to 10 Torr or less.
The reactant gas is introduced into the Pelger as an all-organic gas alone or an inert gas such as He or Ar as all the gear gas, and the pressure is maintained at f 0.1-2 Torr, and high-frequency power of 5-100 W is applied to generate plasma on the substrate. A polymeric film is formed.

The organic gas (monomer) used here can be a gas or a liquid at room temperature. If it is a liquid, it is good to use a J1, carrier gas to carry it into a steam system □ i 7? The characteristics of the plasma polymerization method are that the adhesive strength is generally strong regardless of the substrate, and the monomer does not necessarily require an unsaturated group such as a vinyl group. Some specific examples include pentamethelcyclobe/tasiloxane, 1.3.5-trivinyl-1,,3,5-trimethylcyclotrisiloxane,
So-called Mirotsuki silicon compounds such as hexaphenylcyclotrisiloxane, phenyltriethoxysilane, l-ethoxysilane, tetrafluoroethylene, and 1-1
A fluorine compound such as 0 trifluoroethylene or monochloropentafluoromeroethane may be used as long as the formed film has poor heat resistance.

The perpendicular magnetic anisotropy magnetic film has a hexagonal close-packed structure that breaks the large crystal magnetic anisotropy in the C-axis force direction.

Cobalt-chromium, cobalt-ruthenium, cobalt-rhenium, cobalt-ommium alloy lx total, C
It is manufactured by forming a film by arranging the axis strongly in the vertical direction of the entire substrate. The production method is Sunoku Tsuta Link (DC
, RF, magnetron, ion beam), vacuum evaporation,
Examples are described below, but the scope of the present invention is not limited to all examples. 20
tan XO, 5wn), 2. Borii ζdo (20X2
0 Xo, 05), 3. Single crystal Si Ueno・-(40
φX O, 2, mirror polished (1113 surfaces), 4. Anodized alumite aluminum alloy substrate (the alumite layer is 2I
#n thickness), 5. T1 Sunoku Ivy Glass (Ti base is 0.
3μm thick, glass is 20X20X0.5), 6. Cr
Sputter glass (Cr base is 0.3 μm thick; glass is 2
Six citrons (0x20xo05) were used.

The plasma-polymerized film was formed as follows and was heated to a zero vacuum of 25 x 10 Torr (7), then introduced into a Pelger as the octamethylcyclotetrasiloxane reaction residue using Ar as a carrier gas.
The flow rate is Ill cc/min under standard conditions, and the total pressure is 1.
0 Torr, sieve frequency of 13.56 MHz -110
W' [Apply for 3 minutes with squid, about 320 in/min film type I
A polymer film of about 96 OA was completely formed at the IW speed.

The curved-strength anisotropic film is made of Co-C by RF sputter link.
An r alloy film was formed. Sputtering using CJ119.4 atomic% Cr-Co alloy target, ultimate vacuum degree 5
X 10 Torr or less, pore formation speed close ~90A/
Minutes.

Under the condition that the film thickness is approximately 1/a, the substrate temperature '(m110 ~
160°C, sputtering Ar pressure f1, 0~40X1
．． (3 levels of C-axis orientation)
A whole Co-Cr alloy film was prepared.

When a Co-Cr film is formed directly on a non-magnetic substrate.

In the case of the present invention in which a plasma polymerized film is formed on a non-magnetic substrate and a Co-Cr film is formed on it, the substrate V depends on △θ+10 (the dispersion angle in the normal direction of the substrate IF of the C axis of a hexagonal close-packed structure). The measurement results are shown in Tables 1 to 3.

Table 1 Table 2 Table 3 In the conventional method that does not form a plasma polymerized film, S
△θ of i-wafer, alumite base, Ti base, CL/base. However, in cases 1-7 of forming the plasma polymerized film of the present invention, the mask fL, Δθ, 0 may be due to the influence of the substrate or underlying layer.
is a small value that is almost constant regardless of the substrate.

In particular, the effect of reducing Δθso L7) is remarkable on alumite substrates, Ti, and Cr substrates with fine grain oak (50 to 5 ook) surface roughness and non-uniformity. Depending on the sputtering conditions, as shown in Figure 3, glass substrates can also be used in the present invention. Can be reduced or stirred. Furthermore, even when peeling of the magnetic film is observed as shown in Table 2 VC, no peeling is observed for the magnetic film according to the present invention. Using an aluminum alloy substrate with an alumite base and using the same plasma polymerized film forming method and Co-Cr film forming method as in Example 1, Δθ was determined depending on the thickness of the plasma polymerized film.

Figure 2 shows the results of examining changes in . △θ, 0 is approximately 0
．． Step 8: Forming a 2 μm thick plasma polymer film
．． It decreased from 6° to 4.8°.

(Example 3) Using the Ti sputtered glass substrate used in Example 1 as a nonmagnetic substrate, the same plasma base metal film as in Example 1 was formed, and a cobalt-ruthenium alloy film was used as the magnetic thin film exhibiting perpendicular anisotropy. 'K was formed by RF sputtering. Sputtering is performed using a target in which ruthenium pellets are placed on a pure cobalt disk (the area occupied by the ruthenium pellets is approximately 30% of the total area of the target).
using an ultimate vacuum of 5 x 10 Torr, a substrate temperature of 200°C, a film formation rate of 200^/min, and a spack Ar pressure of 5. Used at OX River - 2'l"orr, approximately 1 μm
0 plasma 1 with a cobalt-ruthenium alloy film formed
When forming a cobalt-ruthenium alloy film on a T1 sputtered glass substrate, Δθ5o is -15.
, at 4°.
The angle decreased to approximately 8.5° when

As explained above, five aspects of the present invention)1. By forming a plasma-polymerized film on a non-magnetic substrate, it prevents the low-toe phenomenon of C-axis orientation caused by the substrate, improves the overall C-axis orientation, and prevents peeling of the magnetic film. , stress concentration due to head contact through the intervention of soft plasma polymerization 11Q can be obtained. Therefore, by using the present invention, it is possible to create a recording/reproducing system in which a perpendicular magnetic recording medium is used without being subject to restrictions from the viewpoint of magnetic film formation (disk, tape, card, etc.), environment, and cost. In addition to being able to select a substrate with due consideration, there is an advantage that a high quality perpendicular magnetic recording medium having high perpendicular magnetic anisotropy and excellent hardness can be easily realized.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a plasma polymerized film forming apparatus, and Fig. 2 shows perpendicular magnetic anisotropy C depending on the plasma polymerized film thickness. - Talk about all the changes in ΔθI and o of the Cr film. 1... Belljar, 2... Vacuum pump,
3... Monomer gas inlet, 4... Porous ring for monomer diffusion, 5... Upper electrode, 6...
・Lower electrode, 7...High frequency power supply, 8...
Substrate patent applicant Nippon Telegraph and Telephone Public Corporation 1 Figure 72

Claims (1)

[Claims] On a non-magnetic substrate, a chassis thin film 7 formed by glow discharge of a scum-like organic compound is provided, and a hexagonal close-packed cobalt oxide film with perpendicular magnetic anisotropy M in the direction perpendicular to the substrate is placed on IF-7. is a perpendicular magnetic recording medium characterized by having a cobalt-based alloy magnetic film.