JPH079702B2 - Magnetic memory manufacturing method - Google Patents

Description

The present invention relates to a magnetic memory used in a magnetic memory (such as a magnetic disk device and a magnetic drum device) and a method for manufacturing the same.

(Prior Art) Generally, there are roughly two types of storage / reproducing methods of a magnetic storage device having a recording / reproducing magnetic head (hereinafter referred to as a head) and a magnetic storage body as main components. The first method is a method of making a space corresponding to an air layer between the head and the surface of the magnetic memory at the start of operation, and recording / reproducing in this state. In this method, the rotation of the magnetic storage body stops at the end of the operation, and at this time, the head and the surface of the magnetic storage body are in the contact friction state as at the start of the operation. In the second method, the magnetic memory is given a predetermined rotation in advance, and the head is suddenly pressed onto the surface of the magnetic memory to form a space corresponding to an air layer between the head and the surface of the previous magnetic memory, This is a method of storing and reproducing in this state. As described above, in the first method, the head and the magnetic memory surface are in a contact friction state at the start and end of the operation, and in the second method, the head is in a contact friction state when the head is pressed against the magnetic memory surface. The frictional force generated between the head and the magnetic storage medium in these contact friction states may wear the head and the magnetic storage medium and eventually cause damage to the head and the metal magnetic thin film medium.

Further, in the contact friction state, a slight change in the posture of the head may make the load applied to the head non-uniform, and may scratch the surface of the head and the magnetic memory.

Further, the frictional force generated between the head and the magnetic memory in the contact state causes a large torque particularly when a large number of heads are mounted, and imposes an unfavorable burden on the motor for rotating the magnetic memory.

Further, during recording / reproduction, the head suddenly contacts the magnetic storage body, a large frictional force acts between the head and the magnetic storage body, and the head and the magnetic storage body are often destroyed.

In order to protect the head and the magnetic storage body from such contact frictional force between the head and the magnetic storage body, it is necessary to coat the surface of the magnetic storage body with a protective coating. It is required to reduce the contact frictional force generated between the memory bodies (that is, reduce the frictional force).

Providing a lubricating layer on the surface of the magnetic memory is one method for reducing the contact frictional force. The lubricating layer must be well bonded to its substrate. If the lubricating layer is not sufficiently bonded to the base, it will be removed from the base due to contact friction between the head and the magnetic memory, or a large amount will collect around the head and between the head and the magnetic memory due to capillarity and recording. This adversely affects the floating stability of the head during playback.

The effect of reducing the contact frictional force between the lubricating layer and the head is achieved by interposing a non-polar molecular layer, which is unlikely to be adsorbed or adhered, at the interface between the head and the magnetic memory. That is, it is desirable that the lubricating layer is oriented in a non-polar molecular layer that is less likely to be adsorbed or cohesive with the portion that binds to the magnetic memory.

As such a lubricating layer, oils such as silicone oil, fluorine oil and fluorosilicone, silanes such as octadecyltrichlorosilane and hexamethyldisilazane, or silazanes have been proposed (Japanese Patent Publication No. 55-40932). Although these lubricating layers each exhibit excellent characteristics, the bonding force for chemically bonding with the amorphous inorganic oxide is insufficient in oils, and the surface due to the presence of a non-polar molecular layer in silane or silazanes. Not enough energy reduction. Therefore, there is a problem in that the effect of reducing the lubricant loss in the case of long-term use in oils and the effect of reducing the contact frictional force generated between the head and the magnetic memory in silane or silazane are not perfect.

An object of the present invention is to provide a magnetic memory body and a method of manufacturing the magnetic memory body that solve this problem.

(Means for Solving the Problems) In the present invention, a metal magnetic thin film medium is coated on an alloy disk coated with a mirror-polished non-magnetic alloy layer or on a mirror-polished alloy disk, and an amorphous film is formed thereon. A high-quality inorganic oxide layer,
Further on the amorphous inorganic oxide layer, the general formula (Wherein R is a fluoroalkyl group, at least one of X, Y and Z is an alkoxy group or chlorine, and the other is an alkyl group) is vapor-phase grown, or after vapor-phase growth, firing is performed to obtain the above-mentioned amorphous compound. Is a method for producing a magnetic memory body, characterized in that a porous inorganic oxide layer is bonded to the compound.

In addition, a metal magnetic thin film medium is coated on an alloy disc coated with a mirror-polished non-magnetic alloy layer or on a mirror-polished alloy disc, and an amorphous inorganic oxide layer is coated on this medium, in plasma. After the treatment, on the amorphous inorganic oxide layer,
General formula (Wherein R is a fluoroalkyl group, at least one of X, Y, and Z is an alkoxy group or chlorine, and the other is an alkyl group). A method for producing a magnetic memory body, which comprises bonding the crystalline inorganic acid compound layer and the compound.

(Operation) The amorphous inorganic oxide is a film of polysilicic acid or SiO ₂ , glass, alumina, etc. Alkoxysilyl group And chlorosilyl group Is highly reactive and chemically bonds with the silanol groups (Si-OH) and hydroxyl groups (-OH) present on the surface of this amorphous inorganic oxide to firmly bond the amorphous inorganic oxide and the lubricant molecule. On the other hand, the fluoroalkyl group arranged on the surface lowers the surface energy and exhibits an excellent lubricating effect. Therefore, the general formula (R is a fluoroalkyl group, at least one of X, Y and Z is an alkoxy group or chlorine, and the other is an alkyl group)
It is expected that an excellent lubricant that is firmly bonded to the base material can be obtained by using the compound represented by. Here, the fluoroalkyl group is a functional group in which some or all of the hydrogen atoms of the alkyl group are substituted with fluorine. In addition, the base material and the compound are firmly bonded to each other as they are,
After forming the amorphous inorganic oxide, it is possible to complete the cleaning of the surface by vapor-depositing the lubricant after treating it in plasma, and the ion-implantation of alkoxysilyl and chlorosilyl groups. The bond between the base body and the lubricant is further strengthened due to the generation of radicals that chemically bond with each other.

Further, for recording and reproduction, it is advantageous that the spacing (the distance between the head and the magnetic memory at the time of recording and reproduction) is small. Therefore, it is desirable that the film thickness of the lubricating layer is as thin as possible, but this compound can form a very thin lubricating layer. That is, by vapor-depositing lubricant molecules on the amorphous inorganic oxide, a lubricating layer composed of a single-hand child layer is automatically formed. It should be noted that although it is strongly bonded to the oxide only by vapor phase growth, it takes a shorter time if firing is performed after vapor phase growth.

(Example 1) Hereinafter, the present invention will be described in detail with reference to Examples. FIG. 1 is a sectional view showing the structure of the magnetic memory body of the present invention.
In the drawing, in the magnetic memory according to the present invention, a non-magnetic alloy layer 2 is coated on an alloy disk 1, and a metal magnetic thin film medium 3 is coated on the polishing surface of this coating. The oxide 4 is coated, and the lubricant 5 is further coated thereon.

Nickel-phosphorus as the non-magnetic alloy layer 2 on the disk-shaped aluminum alloy substrate finished on the surface having a sufficiently small waviness (50 μm or less in both the circumferential direction and the radial direction) by lathe processing and heat correction as the alloy disk 1 Ni-
P) alloy is plated to a thickness of about 50 μm, and this Ni-P plated film is mechanically polished to a surface roughness of 0.04 μm or less and a thickness of about
After mirror-finishing to 30 μm, a cobalt-nickel-phosphorus (CoNi-P) alloy as a metal magnetic thin film medium 3 was plated thereon to a thickness of about 0.05 μm. Furthermore, this Co-Ni-
On the P alloy film, a solution having the composition shown below was thoroughly mixed, and dust or precipitated SiO ₂ was removed through the permeation film and then applied by spin coating.

Tetrahydroxysilane 11% ethyl alcohol solution: 2
0% by weight n-butyl alcohol: 80% by weight After that, the disc substrate was baked at a temperature of 200 ° C. for 3 hours, and then C
A polysilicic acid coating was formed on the o-Ni-P alloy film.

This substrate is treated with (heptadecafluoro-1,1,2,2-tetrahydrodecyl) -1-trichlorosilane (C ₈ F ₁₇ CH ₂ CH ₂ SiC
l ₃ ) in steam for 30 minutes at room temperature and then at 100 ° C for 3
It was baked for 0 minutes to form a lubricating layer composed of a monomolecular film.

When the surface energy of the substrate surface before and after forming the lubricant is calculated by measuring the contact angles of droplets having various surface tensions,
43 erg / cm ² on the polysilicic acid film to 11 erg / c after forming the lubricating layer
It was found that the effect of preventing the adhesion between the head and the base body was large by decreasing to m ² .

Next, the dynamic friction coefficient acting between the disk substrate and the head was measured. The dynamic friction coefficient was determined by connecting a strain gauge to the head, measuring the dynamic friction force between the head and the disk generated when the disk was rotated at a constant speed, and dividing this by the load applied to the head. Measurement is load 15g, sliding speed 1
It was performed under the condition of 00 mm / min. As a result, 0.221 was obtained as the value of the dynamic friction coefficient, and the value of the dynamic friction coefficient could be made smaller than 0.546 when the polymer was not used.

A contact friction test between the disk and the head was repeated 30000 times using a disk substrate coated with this polymer and a monolithic head with a load of 70 g, but there was no change in the surface condition of the disk due to head crash or contact friction by the head. Met.

(Example 2) a disc substrate formed similarly created polysilicic acid film as in Example 1 (Heputadekafuroro 1,1,2,2-tetrahydronaphthalene Te Sil) -1-triethoxysilane [C ₈ F ₁₇ CH ₂ CH ₂ Si <O
C ₂ H ₅ > ₃ ] steam was kept at room temperature for 30 minutes and then baked at 100 ° C. for 30 minutes to form a lubricating layer made of a monomolecular film. The values of the surface energy and the dynamic friction coefficient were obtained by the same method as in Example 1. As a result, the value of surface energy by applying a polymer is reduced from 43erg / cm ² to 12erg / cm ^2, the value of the dynamic friction coefficient could be reduced to 0.245 from 0.546.

Further, the abrasion resistance was evaluated in the same manner as in Example 1, but there was no change in the surface condition of the disk due to the contact friction test of 30,000 times.

(Example 3) a disc substrate formed similarly created polysilicic acid film as in Example 1 (Heputadekafuroro 1,1,2,2-tetrahydronaphthalen-decyl) -1-methyldichlorosilane [C ₈ F ₁₇ CH ₂ CH ₂ Si
<CH ₃ > Cl ₂ ], kept at room temperature for 30 minutes, then 100 ℃
A lubricating layer composed of a monomolecular film was formed by baking at the temperature of 30 minutes. The values of the surface energy and the dynamic friction coefficient were obtained by the same method as in Example 1. As a result, it was possible to reduce the surface energy value from 43 erg / cm ² to 15 erg / cm ² and the dynamic friction coefficient value from 0.546 to 0.253 by applying the polymer.

Further, the abrasion resistance was evaluated in the same manner as in Example 1, but there was no change in the surface condition of the disk due to the contact friction test of 30,000 times.

(Example 4) Co-Ni of a disk substrate prepared by the same method as in Example 1
Instead of the polysilicic acid coating, Al ₂ O ₃ (amorphous alumina) was coated on the -P alloy film by the sputtering method. This disk substrate was processed in the same manner as in Example 1 (heptadecafluoro-1,1,2,
2-Tetrahydrodecyl) -1-trichlorosilane (C ₈ F
₁₇ CH ₂ CH ₂ SiCl ₃ ) steam at room temperature for 30 minutes
A lubricating layer made of a monomolecular film was formed by firing at a temperature of 00 ° C. for 30 minutes, and the surface energy and the coefficient of dynamic friction were determined by the same method as in Example 1. As a result, by applying the polymer, the values of surface energy decreases from 45erg / cm ² to 10erg / cm ^2, the value of the dynamic friction coefficient could be reduced to 0.198 from 0.270.

Further, as in Example 1, there was no change in the disk surface state due to the contact friction test of 30,000 times.

(Example 5) A disk substrate prepared in the same manner as in Example 1 and having a polysilicic acid film formed thereon was placed in a parallel plate type etching apparatus,
Flow rate 18sccm, power density 0.35w / cm ² , pressure 1.3 using Ar
After etching for 2 minutes under the condition of Pa. Bias unit of 1 KV, in a vapor of (heptadecafluoro-1,1,2,2-tetrahydrodecyl) -1-trichlorosilane (C ₈ F ₁₇ CH ₂ CH ₂ SiCl ₃ ). It was kept at room temperature for 30 minutes and then baked at 100 ° C. for 30 minutes to form a lubricating layer composed of a monomolecular film. Example 1
The surface energy and the value of the dynamic friction coefficient were measured by the same method. As a result, the value of the surface energy is reduced further than in the absence of 9erg / cm ² and Ar plasma treatment from 50erg / cm ² with a polymer coating speed of the polysilicic acid coating after treatment with Ar plasma, the dynamic friction coefficient The value could also be reduced from 0.614 on polysilicic acid to 0.201 after polymer coating.

Further, as in Example 1, there was no change in the disk surface state due to the contact friction test of 30,000 times.

(Effects of the Invention) As described above, the magnetic memory according to the present invention has a large effect of reducing the contact frictional force generated between the head and the magnetic memory,
The application is expected after the magnetic disk device and the magnetic drum device.

[Brief description of drawings]

 FIG. 1 is a view showing a cross section of a magnetic memory body of the present invention. The numbers in the figure indicate the following. 1 ... Alloy disc 2 ... Non-magnetic alloy layer 3 ... Metal magnetic thin film medium 4 ... Amorphous inorganic oxide 5 ... Lubricant

Claims (2)

[Claims] 1. A metal magnetic thin film medium is coated on an alloy disc coated with a mirror-polished non-magnetic alloy layer or on a mirror-polished alloy disc, and an amorphous inorganic oxide layer is coated thereon. Further on the amorphous inorganic oxide layer, the general formula (Wherein R is a fluoroalkyl group, at least one of X, Y, and Z is an alkoxy group or chlorine, and the other is an alkyl group). A method of manufacturing a magnetic memory, comprising bonding a crystalline inorganic oxide layer to the compound. 2. A metal magnetic thin film medium is coated on an alloy disc coated with a mirror-polished non-magnetic alloy layer or on a mirror-polished alloy disc, and an amorphous inorganic oxide layer is coated thereon. After the treatment in plasma, on the amorphous inorganic oxide layer, the general formula (Wherein R is a fluoroalkyl group, at least one of X, Y, and Z is an alkoxy group or chlorine, and the other is an alkyl group). A method of manufacturing a magnetic memory, comprising bonding a crystalline inorganic oxide layer to the compound.