JPH07244947A - Magnetic disk device, magnetic disk and production of magnetic disk - Google Patents

Abstract

PURPOSE:To obtain a magnetic disk having a high recording density and high reliability by forming island-shaped very small projecting parts on the surface of a substrate for the magnetic disk, thereby decreasing the adhesive force between the magnetic disk and a magnetic head. CONSTITUTION:A cerium pad consisting of a foamed polyurethane impregnated with cerium oxide is used as polishing cloth and fine powder of cerium oxide is used as a abrasive compound in the case of using a crystallized glass substrates as a magnetic disk substrate. The glass substrate is formed to gentle shapes A by a grinding method using the cerium oxide having an average grain size of 1 to 3mum. Crystallized particles 7 form projecting shapes and amorphous parts 8 form recessed shapes in the crystallized glass substrates. The shapes B are formed by smoothing by this working method. Further, the shapes C are obtd. by a working method using a mechanochemical grinding method. The nuclei 21 in the central parts of the crystal particles 7 are projected more than outer peripheral parts 22 including the nuclei 21 and the projecting parts smaller than the crystal particle are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device adapted to a high recording density, and more particularly, to a surface property of a magnetic disk, a head floating characteristic, a CSS characteristic, a sliding resistance characteristic such as head adhesion of the magnetic disk. The present invention relates to a magnetic disk device having a magnetic disk having a surface texture suitable for improving the magnetic field.

[0002]

2. Description of the Related Art Conventionally, a thin film magnetic disk has an aluminum alloy surface which is plated with Ni-P, and the surface of the thin film magnetic disk is made uneven by texture processing using abrasive grains.

Further, as to the crystallized glass of the prior art, as described in Japanese Patent Application Laid-Open No. 2-187922, a mixed phase of a crystalline phase and an amorphous phase is used to form minute convex portions on the surface. The method is shown.

On the other hand, in order to increase the recording capacity of the magnetic disk device, the flying height of the magnetic head is required to be extremely small, and it is required to be narrower than 100 nm. Therefore, the roughness of the substrate surface of the textured disk has a surface state close to that of the polished processed surface with small surface irregularities. Therefore, in order to reduce the flying height, it is necessary to reduce the surface roughness of the textured surface. With such a substrate-shaped magnetic disk,
The frictional force increases due to the increase in the contact area with the magnetic head and the magnetic head slider, and the magnetic head after temporary rest adheres to the magnetic disk surface, causing damage to the head support system or disk drive when the magnetic disk device is started. There was a problem that the motor did not rotate.

[0005]

In the prior art, as a magnetic disk substrate, a substrate in which an aluminum alloy surface is plated with nickel-phosphorus is used, and unevenness is formed on the substrate surface by texturing using abrasive grains. The concavo-convex shape is formed mainly on a concentric circle with respect to the substrate, and the convex portion has a continuous ridge shape. Therefore, the contact between the opposing surfaces of the magnetic head and the magnetic disk becomes linear, and the ratio of the contact surfaces (load ratio) increases. There is a method of further increasing the unevenness in order to reduce the ratio of the contact surface, but it is not suitable for reducing the flying height of the magnetic head. Therefore, in order to reduce the unevenness and also reduce the contact area between the magnetic head and the magnetic disk, there arises a problem that the convex portion has an island shape (island shape).

As a conventional technique relating to crystallized glass, as described in Japanese Patent Application Laid-Open No. 2-187922, a method of forming a convex crystal phase is shown. However, only the entire crystalline phase forms a convex portion, and the relationship between the nucleus in the crystalline phase and the peripheral portion including the nucleus is not described, and it is possible to make the convex portion smaller than the fine particles of the crystalline phase. Can not.

Therefore, the present invention provides a magnetic disk device in which the contact area between the magnetic disk and the magnetic head in the magnetic disk device is reduced to improve the low flying property and sliding resistance between the magnetic head slider and the magnetic disk. The purpose is to provide.

Another object of the present invention is to provide a magnetic disk applied to a magnetic disk device, which has a surface property excellent in low floating property and sliding resistance with respect to a magnetic head or a magnetic head slider. Is to provide.

Still another object of the present invention is to provide a magnetic disk applied to a magnetic disk device, which has a surface property excellent in low flying property and sliding resistance with respect to a magnetic head or a magnetic head slider. It relates to a forming method.

Still another object of the present invention is a magnetic disk device to which the present invention is applied, which is a mechanism for reducing the influence of contact between the magnetic head slider and the magnetic disk when the device is in operation, The present invention relates to a surface shape of a magnetic disk substrate of a magnetic disk having at least a magnetic layer, a protective layer, and a lubricating layer, or a metal film on the magnetic disk.

[0011]

In order to achieve the above object, the present invention is directed to a case where fine particles having a nucleus in a central portion and having an outer peripheral portion including the nucleus are island-shaped on the surface of a magnetic disk substrate or a magnetic disk. A magnetic disk that has a portion that is scattered over the surface of the particle and that protrudes from the surface on which the particles are formed, the protrusions are formed by the core of the center of the particle, and the outer peripheral portion including the core forms a smooth surface. At least a magnetic disk device has a magnetic head slider having a magnetic head for recording / reproducing. At this time, the magnetic disk to which the present invention is applied has a convex portion smaller than the outer shape of the fine particles, can keep the surface roughness of the magnetic disk smooth, and can have fine protrusions. The low floating property and the sliding resistance are improved.

A case where a crystallized glass substrate is used as the magnetic disk substrate will be described. The crystallized glass substrate forms crystal grains centering on crystal nuclei, and each crystal grain is surrounded by an amorphous layer. In the conventional substrate manufacturing method, press molding of a substrate, end face processing, parallel lap processing, and polishing processing for smoothing the surface roughness are performed. In the polishing process which is the final step, conventionally, a method of polishing glass on a hard foamed polyurethane pad containing cerium oxide via an aqueous cerium oxide solution has been adopted. Also, large abrasive particles have been used to shorten the processing time. Therefore, the surface roughness was 10 to 40 nanometers due to the mechanical scratching action of the abrasive cerium oxide.

A method of forming minute irregularities on the surface of a glass substrate has been considered by utilizing the fact that the crystallized glass substrate is composed of a nucleus portion of crystal grains, an outer peripheral portion including the nucleus and an amorphous portion. . The core part of the crystal grain and the peripheral part including the core and the amorphous part are processed to have different processing characteristics, so that only the core part of the crystal grain is processed into a convex shape to include the core. It is possible to form an island-shaped magnetic disk substrate having a high density and fine projections by using the outer peripheral portion and the amorphous portion as smooth surfaces.

As shown in FIG. 19, the magnetic disk 20 has a base film 31 of Cr or the like, a magnetic film 32 of Co alloy, a protective film 3 of carbon or the like on the surface of the magnetic disk substrate 30.
3 Obtained by further forming a fluorine-based lubricating film 34. The surface shape of the magnetic disk after forming the magnetic film and the protective film on the magnetic disk substrate remains unchanged from the shape of the substrate before film formation. Therefore, when the substrate-shaped convex portion is formed on the magnetic disk substrate before forming the magnetic film or the protective film, the convex shape on the surface of the magnetic disk is defined. Here, as shown in FIG.
1 is installed on the surface of the magnetic disk 80, several magnetic disks are stacked, or one magnetic disk is assembled to form a magnetic disk device. In this magnetic disk device, when the device is operated, the magnetic head slides on the disk surface as shown in FIG. 21, and the air flow intervenes between the disk surface and the head slider 82 surface (shown in FIG. 22). The magnetic head floats, and when the apparatus stops, the magnetic head comes to rest on the disk surface. This operation is generally called Contact-Start-Stop (CSS).
Call it a characteristic. The present invention reduces the flying height of the magnetic head when the magnetic head flies above the disk surface during CSS, avoids head adhesion when the magnetic head is stationary on the disk surface, and further It is possible to reduce the contact force between the magnetic head and the magnetic disk while sliding on the disk surface.

Also for magnetic disk substrates other than crystallized glass, a magnetic film, a protective film, and a lubricating film are formed on a magnetic disk substrate having an island-like surface shape with high density and fine projections by a method of controlling fine particle projections. It can be a magnetic disk. Specifically, on the substrate or on each layer provided on the upper part of the substrate, fine particles having a nucleus in the center and an outer peripheral portion including the nucleus are provided, and the nucleus portion of the crystal grain and the outer periphery including the nucleus are provided. By making the processing state in which the processing characteristics are different in the part and the amorphous part, a processing method is performed in which only the core part of the crystal grain has a convex shape, and the outer peripheral part including the core and the amorphous part are smooth surfaces, It is possible to obtain an island-shaped magnetic disk having high density and fine protrusions.

[0016]

[Operation] Attention is paid to the pressing of the abrasive grains into the crystalline portion and the amorphous portion. When the abrasive grains are pressed into the workpiece, the scratch marks of the abrasive grains are transferred as a substrate shape, and a surface roughness shape is formed. It is considered that the mechanical action of the abrasive grains as the abrasive is influenced by the particle size of the abrasive grains, the pressing pressure, and the material. The pressing pressure of finer abrasive grains than that of crystal grains is not determined only by the load applied to the entire polishing cloth, but microscopically determined by the hardness of the polishing cloth that supports the abrasive grains.

Further, attention is paid to the workability between the core part of the crystal grain and the outer peripheral part including the core. By setting the processing amount difference due to the difference in mechanical / chemical polishing action between the core of the crystal grain and the outer peripheral portion including the core, the core portion of the crystal grain can be formed in the convex portion.

Therefore, by selecting the material of the disk substrate, the abrasive grains of the polishing agent and the polishing cloth and controlling the processing characteristics thereof, a processing amount difference of nanometer order is provided on the disk substrate to form an island shape. It is possible to form a high density and fine convex shape.

[0019]

Embodiment An embodiment of the present invention will be described with reference to the drawings.

A processing method for forming the shape of the magnetic disk substrate will be described with reference to FIG. In the processing step 1, a hard polishing pad having a hardness of 70 to 80 degrees, that is, a hard pad 3 for short is attached to the upper surface plate 1 and the lower surface plate 2 of the double-side polishing apparatus. In the processing step 2, a soft polishing pad having a hardness of 20 degrees, that is, a soft pad 4 for short is attached to the upper and lower surface plates 1 and 2 of the double-side polishing apparatus. The magnetic disk substrate 5 is the upper and lower surface plate 1,
It is held via carrier 6 between the two. In both the processing step 1 and the processing step 2, fine powder of silicon dioxide is used as an abrasive. The polishing hard pad 3 and the soft pad 4 are pressed against the disk substrate 5 respectively, a polishing pressure is applied thereto, and they are slid relative to each other through an abrasive for polishing.

A model for forming the surface shape of the magnetic disk substrate according to the present invention will be described with reference to FIG. A case where a crystallized glass substrate is used as the magnetic disk substrate will be described.
Cerium oxide is used as a conventional glass substrate polishing method. According to this method, a cerium pad made of expanded polyurethane impregnated with cerium oxide is used as a polishing cloth, and cerium oxide fine powder is used as an abrasive. Abrasive grains of cerium oxide act mainly on the mechanical action on the glass substrate, the surface of the glass substrate is formed according to the abrasive grain size of cerium oxide, and polishing using cerium oxide having an average abrasive grain size of 1 to 3 μm By law, the glass substrate is gentle (A)
Shaped, the surface roughness is 10 to 40 nm Rmax
become. In the crystallized glass substrate, the crystal grains 7 have a convex shape,
The amorphous portion 8 has a concave shape and forms an uneven surface. The average abrasive grain size of cerium oxide is 1 to 3 μm,
Regarding the method of processing a glass substrate for a magnetic disk using abrasive grains of m or less, the formation of nanometer-ordered shapes on the processed surface has not been clarified. The (B) shape is obtained by the smoothing processing in the processing step 1 according to the present invention. Crystal grain 7
The core 21, the outer peripheral portion 22 including the core 21, and the amorphous portion 8 form a smooth surface. Further, the (C) shape is obtained by the processing method using the mechanical chemical polishing method. In the shape (C), the nucleus 21 at the central portion of the crystal grain 7 is formed as a protrusion as compared with the outer peripheral portion 22 including the nucleus 21. The core 21 at the center of the crystal grain forms a minute convex shape, and the outer peripheral portion 22 including the center of the crystal grain and the amorphous portion 8 form a smooth surface. It is formed.

FIG. 3 shows the shape of the machined surface according to the present invention as measured by a surface roughness meter. The cross-sectional shape obtained by the conventional processing method using cerium oxide is (D), which is a smooth surface and has a surface roughness of 20 nmRmax. The smoothed surface of FIG. 2B according to the present invention is a smooth surface of 3 nmRmax as shown in the sectional shape (E). further,
As shown in the sectional shape (F), the textured surface by the mechanical chemical polishing method of FIG. 2 (C) according to the present invention forms island-shaped convex portions of 15 to 20 nmRmax.

FIG. 4 shows the surface shape of the magnetic disk substrate according to the present invention observed by an atomic force microscope. FIG. 4 shows a smooth polished surface by the conventional processing method. FIG. 5 shows a machined surface according to the present invention. As shown by the measurement result by the atomic force microscope, 4 × 10 ⁶ island-shaped projections according to the present invention are formed in a 1 mm square area.

FIG. 6 shows an observation result of the shape of FIG. 5 by an electron microscope. Cross-sectional photograph According to FIG. 6 (A), there is a fine protrusion in the center of the crystal grain, and the size of the crystal grain is about 1 μm.
m, the size of the protrusion is about 0.1 μm, the height of the protrusion is 20 to 30 nm, and the size of the protrusion is about 1/10 of the crystal grain, which is smaller than the crystal grain. A part including the core excluding the core part of the crystal grain and the amorphous part form a smooth surface. According to the plan view (FIG. 6 (B)), the protrusion density is 4.4 × 10 ⁶ pieces / 1 mm ²
Is.

FIG. 7 shows the smoothing effect of the glass substrate by reducing the abrasive grain size of the abrasive. When using cerium oxide as the polishing agent, which is the conventional processing method, the average abrasive grain size is 1.3 μm.
To 2.5 μm, as shown in FIG.
It has a gentle shape of around 10 nmRp. By using the hard polyurethane foam polishing pad according to the present invention as the polishing cloth and using the fine powder of silicon oxide as the polishing agent, it becomes 10 nmRp to 2 nmRp as compared with the case of using cerium oxide, and the cross section of FIG. It can be smoothed as shown by the curve.

FIG. 8 shows the influence of the combination of the hardness of the polishing pad and the abrasive grain size of the polishing agent on the surface roughness shape of the glass substrate. 7 when using fine silicon oxide as an abrasive
-1, cerium oxide having an average abrasive grain size of 1.3 μm as an abrasive,
The case of using 2.5 μm is shown in 7-2 and 7-3. When a polyurethane foam polishing pad is used as the polishing cloth and cerium oxide is used as the polishing agent, the hardness of the polishing pad is 20 to 8
At 0 degree, the influence on the surface roughness shape of the crystallized glass substrate is small. This is because the particle diameter of cerium oxide is large and its mechanical polishing action is the main factor for forming the surface shape of the polishing surface. When using fine silicon oxide having an average grain size of 20 nm as an abrasive, the surface roughness shape of the crystallized glass substrate changes depending on the hardness of the polishing pad. That is, the combination of a hard polishing pad having a hardness of 70 to 80 degrees and fine silicon oxide makes the surface roughness shape of the crystallized glass substrate smoother by the mechanical polishing action. Furthermore, by combining a soft polishing pad with a hardness of 20 degrees and fine silicon oxide, it is shown that the fine protrusions of the surface shape are scattered in high density in an island shape by the mechanical and chemical polishing action. There is.

FIG. 9 shows the influence of the processing time on the surface roughness when a soft polishing pad and fine silicon oxide are used as an abrasive for the processed surface of the crystallized glass substrate according to the present invention. Amorphous parts are removed with processing time, crystalline parts form convex parts, and the protruding amount increases,
It shows that the surface roughness becomes large. Processing speed 30
In the processing conditions of m / min and processing pressure of 10 kPa,
The surface roughness Rp becomes 20 to 25 nm in the processing time of 2 to 4 minutes, which shows that the protrusion shape can be controlled by the nanometer order.

FIG. 10 shows the relationship between the surface roughness of the processed surface of the crystallized glass substrate according to the present invention and the load ratio. The area ratio of the waveform at a height 5 nm lower than the protrusion of the cross-sectional shape is called a load ratio of 5 nm, and it is indicated by a in the figure and is 1 from the protrusion.
The area ratio of the waveform at the height lowered by 0 nm is the load ratio 1
It is called 0 nm and is indicated by b in the figure. In the conventional polishing method using cerium oxide for a glass substrate, the surface roughness is 10 nmR
However, the load ratio of 5 nm is 8% or more, and there is concern that the adhesive strength will increase. When a soft polishing pad and fine silicon oxide are used as abrasives, the crystal grains form convex portions, the surface roughness is 20 nmRp, and the load ratio is 5 nm is 0.2.
% Can be obtained.

In FIG. 11, a Co-Cr-Ta magnetic film having a film thickness of 30 n is formed on the crystallized glass substrate having the fine projections formed thereon.
The results of examining the levitation property of the magnetic head with respect to a magnetic disk having a protective film of m, a carbon protective film of 30 nm, and a fluorine-based lubricant of 5 nm will be described. The flying height of the magnetic head has a correlation with the surface roughness shape of the magnetic disk, and the smaller the roughness, that is, the smoother the surface, the smaller the flying height. Compared with the conventional method, in the magnetic disk substrate according to the present invention, for example, when the surface roughness Rp is 20 nm, the head flying height is 50 nm in the conventional method.
It could be reduced to 2 nm.

FIG. 12 illustrates the friction coefficient between the magnetic disk and the magnetic head according to the present invention. In the conventional substrate shape, the surface is smoothed and the surface roughness Rp is 20n.
If it is less than m, the friction coefficient between the magnetic head and the magnetic disk rapidly increases, and the magnetic head adheres to the magnetic disk. In the magnetic disk according to the present invention in which a thin film is formed on the magnetic disk substrate having the convex portion, the surface roughness Rp is 20 nm.
Also in the following, it is possible to suppress the increase of the friction coefficient and prevent the magnetic head from sticking to the magnetic disk. Therefore, in a magnetic disk device including a magnetic disk using a magnetic disk substrate according to the present invention, at the same time, it is essential to achieve high recording density and low reliability of the magnetic head, which is essential for achieving high reliability of the device. Can be achieved,
It was confirmed that a remarkable effect was obtained.

FIG. 13 shows a machining process and a shape model diagram in one embodiment of the present invention. As shown in FIG. 13- (A), fine particles 10 are dispersed and attached to a smooth magnetic disk substrate 9. The fine particles 10 are composed of a core 21 and an outer peripheral portion 22 including the core 21 in the center. As shown in FIG. 13- (B), film growth is performed using the fine particles 10 as nuclei to form the amorphous portion 11. Further, as shown in FIG. 13- (C), the fine particles 1 are formed by a mechanical chemical polishing method using a combination of a soft pad and fine particles.
The nucleus 21 at the center of 0 forms a convex portion, the outer peripheral portion 22 including the nucleus 21 and the amorphous portion 11 form a smooth surface, and the fine convex portions form a magnetic disk substrate scattered in an island shape.

FIG. 14 shows a machining process and a shape model diagram in another embodiment according to the present invention. Figure 14- (A)
As shown in FIG. 1, the magnetic film 1 on the smooth magnetic disk substrate 9
The fine particles 10 are dispersed and adhered to 2. As shown in FIG. 14- (B), film growth is performed using the fine particles 10 as nuclei to form an amorphous portion 11. In order to form the amorphous portion 11, a glassy material may be formed into a film under the optimum conditions by deposition. At this time, it is necessary to control the film thickness to several nm, and film formation by deposition is desirable, but the method is not limited to this method.

Further, as shown in FIG. 14- (C), the core 21 at the center of the fine particle 10 becomes a convex portion by the mechanical chemical polishing method by the combination of the soft pad following the shape of the substrate and the fine particle. The outer peripheral portion 22 including the nuclei 21 and the amorphous portion 11 form a smooth surface, and a magnetic disk substrate in which fine convex portions which are the object of the present invention are scattered in an island shape is formed.

FIG. 15 illustrates another method of processing a magnetic disk according to the present invention, in which the surface shapes of the magnetic disk substrate on the inner peripheral side and the outer peripheral side are different.
In the process 1, a smooth shape is formed on the entire surface of the substrate by combining the hard pad 3 and the fine abrasive grains, and then the partial convex shape is applied by the pressurizing device 13 to which the soft pad to be the processed surface is attached only on the inner peripheral side of the substrate. Perform processing. In the process 2, the convex shape is formed on the entire surface of the substrate by the combination of the soft pad 4 and the fine abrasive grains, and then, the smoothing shape is applied by the pressurizing device 14 to which the hard pad for processing only the outer peripheral side of the substrate is attached. Perform processing.

FIG. 16 shows an outline of a processing apparatus used for the partial convex portion forming method and the partial smoothing method. In process 1, the magnetic disk substrate 5 is supported by the guide roller 15. At the same time, the magnetic disk substrate 5 is pressed from both sides and processed by the pressure device 13 having the soft pad attached only to the inner peripheral side. In process 2, the magnetic disk substrate 5 is supported by the holding jig 16 on the inner peripheral portion. At the same time, the magnetic disk substrate 5 is processed by being pressed from both sides to the pressure device 14 having a hard pad attached only on the outer peripheral side.

The processing area of the magnetic disk substrate 5 will be described with reference to FIG. In the magnetic disk device, the magnetic head floats above the magnetic disk at the inner peripheral portion of the substrate 5,
The data zone 17 is an area for reading and writing magnetic recording. The magnetic head flies over the magnetic disk,
Area to stop, Contact-Start-Stop
The area 18 is called (CSS).

FIG. 18 shows the crystallized glass substrate shapes described in claims 12 and 13. FIG. 14 shows a model diagram of a processed shape when the processing process shown in FIG. 13 is applied to a crystallized glass substrate. In process 1,
The average surface of the zoning 17 has a relatively higher positional relationship in nanometer order than the average surface of the CSS zone 18.
In Process 2, the average surface of the data zone 17 is
Compared to the average surface of the CSS zone 18, the nanometer order has a relatively low positional relationship.

As described above, according to the embodiment of the present invention, by forming the island-shaped minute projections on the surface of the magnetic disk substrate, the surface roughness shape of the magnetic disk substrate is controlled by the nanometer order. In addition, the convex portions can have a uniform distribution. Therefore, in the magnetic disk device, the flying height of the magnetic head with respect to the magnetic disk can be further reduced, and the protrusions can be dispersed to reduce the contact area between the projections to reduce the adhesive force between the magnetic disk and the magnetic head. Therefore, a magnetic disk with high recording density and high reliability can be obtained.

Further, by combining the smoothing step and the convex portion forming processing method to increase the convex amount of the CSS zone of the magnetic disk, the adhesive force between the magnetic disk and the magnetic head can be reduced. In the area where the data is read and written, a smoother processed surface can be formed, and the gap between the magnetic disk and the magnetic head can be narrowed, so that a magnetic disk having a high recording density can be obtained.

The magnetic disks thus obtained according to some embodiments are applied to the magnetic disk apparatus as shown in FIG. 20, and the CSS operation and the recording / reproducing of information are performed by the magnetic head slider 81. It is possible to prevent the magnetic head slider from sticking to the magnetic disk, reduce the load on the magnetic disk drive motor, and achieve a low flying height and stabilization of the flying height of the magnetic head slider or magnetic head, thus achieving high recording of the magnetic disk device. Can have higher density and higher reliability,

[0041]

According to the present invention, a magnetic disk having an island-like surface shape having high density and fine projections, and a magnetic head slider for recording / reproducing information on / from the magnetic disk are put into a good state. A magnetic disk device having high recording density and high reliability can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view of a magnetic disk substrate shape processing method according to the present invention.

FIG. 2 is a model drawing of the surface shape of the magnetic disk substrate according to the present invention.

FIG. 3 is a graph showing a cross-sectional shape of a magnetic disk substrate according to the present invention by a stylus type surface roughness meter.

FIG. 4 is a view showing a result of measuring a surface shape of a magnetic disk substrate by a conventional processing method with an atomic force microscope.

FIG. 5 is a diagram showing a result of measuring a surface shape of a magnetic disk substrate according to the present invention by an atomic force microscope.

FIG. 6 is a diagram showing a result of measuring a surface shape of a magnetic disk substrate according to the present invention with a scanning electron microscope.

FIG. 7 is a diagram showing the effect of smoothing a glass substrate by reducing the abrasive grain size of an abrasive.

FIG. 8 is a diagram showing the influence of the combination of the hardness of the polishing pad and the abrasive grain size of the polishing agent on the surface roughness shape of the glass substrate.

FIG. 9 is a diagram showing the influence of processing time on the surface roughness when a soft polishing pad and fine silicon oxide are used as abrasives with respect to the processed surface of the crystallized glass substrate according to the present invention.

FIG. 10 is a diagram showing the relationship between the surface roughness of the processed surface of the crystallized glass substrate according to the present invention and the load ratio.

FIG. 11 is a diagram showing the relationship between the surface roughness of the processed surface of the crystallized glass substrate according to the present invention and the floating property.

FIG. 12 is a diagram showing the relationship between the surface roughness of the processed surface of the crystallized glass substrate according to the present invention and the coefficient of friction with the magnetic head.

FIG. 13 is a diagram showing a machining process and a shape model diagram in one embodiment of the present invention.

FIG. 14 is a view showing a machining process and a shape model in another embodiment according to the present invention.

FIG. 15 is an explanatory view of a method of making the surface shapes of the inner peripheral side and the outer peripheral side of the magnetic disk substrate different from each other in one embodiment according to the present invention.

FIG. 16 is a diagram showing an outline of a processing apparatus used for a partial convex forming method and a partial smoothing method.

FIG. 17 is an explanatory diagram for explaining a processing area of a partial protrusion forming method and a partial smoothing method of a magnetic disk substrate.

FIG. 18 is a model view of a processed shape when the processing process shown in FIG. 15 is applied to a crystallized glass substrate.

FIG. 19 is a diagram showing a configuration of a magnetic disk to which the present invention is applied.

FIG. 20 is a diagram showing a configuration of a magnetic disk device to which the present invention is applied.

FIG. 21 is a diagram showing a sliding state of a magnetic disk and a magnetic head.

FIG. 22 is a diagram showing the shape of a magnetic head used for evaluating the characteristics of a magnetic disk according to the present invention.

[Explanation of symbols]

1 Upper Plate of Double-sided Polishing Device 2 Lower Plate of Double-sided Polishing Device 3 Hard Polishing Pad 4 Soft Polishing Pad 5 Magnetic Disk Substrate 7 Crystal Particles of Crystallized Glass Substrate 8 Amorphous Part of Crystallized Glass Substrate 10 Fine Particles 13 Pressurizing device with a soft pad attached so that it is processed only on the inner peripheral side of the substrate 14 Pressurizing device with a hard pad attached only on the outer peripheral side of the magnetic disk substrate 15 Guide roller 16 For the inner peripheral portion of the magnetic disk substrate Holding jig 20 Magnetic disk 21 Nucleus at center of crystal grain 22 Peripheral part including nucleus at center of crystal grain 80 Magnetic disk 81 Magnetic head slider 85 Magnetic disk device

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[Procedure amendment]

[Submission date] July 28, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

FIG. 4 is a photograph showing a result of measuring a surface shape of a magnetic disk substrate by a conventional processing method with an atomic force microscope.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 5

[Correction method] Change

[Contents of correction]

FIG. 5 is a photograph showing the result of measuring the surface shape of the magnetic disk substrate in the present invention by an atomic force microscope.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 6

[Correction method] Change

[Contents of correction]

FIG. 6 is a photograph showing the results of measuring the surface shape of a magnetic disk substrate according to the present invention with a scanning electron microscope.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Furusawa 2880, Kozu, Odawara-shi, Kanagawa Stock Company Hitachi Storage Systems Division (72) Inventor, Hiroji 2880, Kozu, Odawara, Kanagawa Hitachi Storage Co., Ltd. System Division

Claims (21)

[Claims] 1. Regarding the surface shape of a magnetic disk substrate, fine particles having a nucleus at the center and consisting of an outer peripheral portion including the nucleus are scattered in an island shape on the surface of the magnetic disk substrate, and the nucleus at the center of the fine particles is The outer periphery including the nuclei and the amorphous part holding the fine particles form a smooth surface, and the nuclei at the center of the fine particles form a convex portion smaller than the outer shape of the fine particles. A magnetic film, a protective film, and a lubricant thin film formed on the surface of a magnetic disk substrate that has a surface shape in which minute convex portions, an outer peripheral portion including nuclei, and an amorphous portion holding fine particles form a smooth surface. A magnetic disk device comprising a disk and capable of improving the low flying property and sliding resistance of a magnetic head. 2. With respect to the surface shape of a magnetic disk substrate, the fine projections of the surface shape are scattered in an island shape, and the density of the fine projections is 1 × 10 ⁶ to 1 × 10 ⁸ pieces / 1 mm ² .
Rp, which represents the height of the minute convex portion that is the surface shape, is 5 to
A magnetic disk having a thickness of 30 nm and a magnetic film, a protective film, and a thin film of a lubricant formed on the surface of the magnetic disk substrate having the features of claim 1. 3. The surface of a crystallized glass substrate has a uniform mechanical polishing action on the crystal grains and the amorphous portion, and includes the crystal nucleus of the crystal grain, the grain portion including the crystal nucleus, and the crystal grain. By making the mechanical-chemical polishing action of the amorphous part different, the processing efficiency of the crystal nucleus is reduced, and the processing efficiency of the peripheral portion including the crystal nucleus and the amorphous portion is increased. A magnetic disk having the characteristics as set forth in claim 1 by a different polishing method, wherein a magnetic film, a protective film, and a lubricating film are formed on the magnetic disk substrate. 4. With respect to the surface of the crystallized glass substrate, in order to uniformly apply a polishing pressure to the crystal grains and the amorphous portion,
By using a combination of a soft polishing pad that follows the substrate shape and particles that are finer than the crystal particles of the crystallized glass substrate, the mechanical and chemical polishing method reduces the processing efficiency of the crystal nuclei and reduces the crystal nuclei. The processing efficiency of the included particle part and the amorphous part including crystal particles is increased, and the magnetic film substrate has the characteristics described in claim 1, and a magnetic film, a protective film, and a lubricating film are formed on the magnetic disk substrate. A magnetic disk characterized in that. 5. A mechanical polishing method for selectively applying a polishing pressure to a convex portion of a crystal grain without following the shape of the substrate composed of the crystal grain and the amorphous portion on the surface of the crystallized glass substrate. Then, the surface shape of the substrate is smooth-polished, and then the mechanical and chemical polishing method is used to have the characteristics of claim 1, and a magnetic film, a protective film,
A magnetic disk having a lubricating film formed thereon. 6. A hard polishing pad for selectively applying a polishing pressure to a convex portion of a crystal grain on the surface of the crystallized glass substrate without following the shape of the substrate composed of the crystal grain and the amorphous portion. A mechanical polishing method that combines fine particles smaller than the crystal particles of a crystallized glass substrate, smoothes the substrate surface shape, and then makes the polishing pressure on the crystal particles and the amorphous part uniform. By a mechanical and chemical polishing method using a combination of a soft polishing pad that follows the substrate shape to be added and fine particles smaller than the crystal particles of the crystallized glass substrate,
A magnetic disk having the features of claim 1, wherein a magnetic film, a protective film, and a lubricating film are formed on the magnetic disk substrate. 7. A smooth surface of an amorphous chemically strengthened glass substrate or a single crystal substrate of silicon or the like is interspersed with fine particles, and the particles are used as nuclei for film growth.
A magnetic disk having the features of claim 1, wherein a magnetic film, a protective film, and a lubricating film are formed on the magnetic disk substrate. 8. A combination of a soft polishing pad and fine particles, in which fine particles are scattered on a smooth surface of an amorphous chemically strengthened glass substrate or a single crystal substrate of silicon or the like, and film growth is performed using the particles as nuclei. A magnetic disk having the characteristics according to claim 1 by a mechanical chemical polishing method using, and a magnetic film, a protective film, and a lubricating film formed on the magnetic disk substrate. 9. A glass substrate, a single crystal substrate such as silicon,
Regarding a magnetic disk in which a smooth surface of a sintered substrate such as carbon or ceramics is used as a substrate material and a magnetic film, a protective film, or a lubricating film is formed on the surface, fine particles are scattered on the magnetic film or the protective film. A magnetic disk having the characteristics of claim 1, wherein a film is grown using the particles as nuclei and a mechanical and chemical polishing method is used using a combination of a soft polishing pad and fine particles. 10. A surface of a crystallized glass substrate is subjected to mechanical polishing by a combination of a hard polishing pad and fine particles to smooth the substrate surface shape, and then to a sliding surface of a magnetic head. The mechanical and chemical polishing method using a combination of a soft polishing pad and fine particles only on the inner peripheral side portion of the contact surface of the magnetic disk, which has the features of claim 1, and has a surface with an uneven surface. A magnetic disk characterized in that a magnetic film, a protective film, and a lubricating film are formed on a magnetic disk substrate having a smooth surface shape on the outer peripheral side. 11. The method according to claim 1, wherein the surface of the crystallized glass substrate has a mechanical and chemical polishing method using a combination of a soft polishing pad and fine particles, and The outer peripheral side of the concavo-convex forming surface is a mechanical polishing method using a combination of a hard polishing pad and fine particles, the substrate surface shape is smooth-polished, and the inner peripheral side of the magnetic disk contact surface in contact with the sliding surface of the magnetic head. A magnetic disk characterized in that an uneven surface is formed only on a part, and a magnetic film, a protective film, and a lubricating film are formed on a magnetic disk substrate having a smooth surface shape on the outer peripheral side. 12. An average surface of surface irregularities formed on a data zone for reading and writing magnetic recording data on the surface of a crystallized glass substrate which is a base substrate of a magnetic disk, the magnetic head stops and floats. In the relative positional relationship with the average surface of the surface irregularities formed on the CSS zone, the average surface of the data zone is relatively higher than the average surface of the CSS zone. A magnetic disk having a magnetic film, a protective film, and a lubricating film formed on its surface. 13. A CSS in which a magnetic head stops and floats on an average surface of surface irregularities formed on a data zone for reading and writing magnetic recording data on the surface of a crystallized glass substrate.
In the relative positional relationship with the average surface of the surface irregularities formed on the zone, the data zone has a relative lower positional relationship than the CSS zone, and the magnetic film, the protective film, and the lubricating layer are formed on these surfaces. A magnetic disk having a film formed thereon. 14. A soft polishing pad that follows a substrate shape for uniformly applying a polishing pressure to crystal grains and an amorphous portion on the surface of a crystallized glass substrate, a grain portion including crystal nuclei and a crystal. A method for mechanical and chemical polishing using a combination with an amorphous part including particles and a grain finer than the crystal grains of a crystallized glass substrate for increasing the mechanical and chemical polishing action, and a double-sided simultaneous polishing apparatus A soft polishing pad is attached to the processed surface to be a polishing tool, fine particles are used as an abrasive, and both surfaces of the crystallized glass substrate are simultaneously polished with the soft polishing pad, thereby making A method of manufacturing a magnetic disk, comprising forming a magnetic film, a protective film, and a lubricating film on a magnetic disk substrate having the characteristics described above. 15. The surface of the crystallized glass substrate does not follow the shape of the substrate composed of crystal grains and amorphous portions,
In order to selectively apply polishing pressure to the convex parts of the crystal particles, the surface shape of the substrate is made smooth by a mechanical polishing method that combines a hard polishing pad and fine particles smaller than the crystal particles of the crystallized glass substrate. Polish and then machine using a combination of a soft polishing pad that follows the substrate shape that uniformly applies a polishing pressure to the crystalline particles and the amorphous portion and fine particles smaller than the crystalline particles of the crystallized glass substrate. Regarding the mechanical and chemical polishing method, a double-sided simultaneous polishing apparatus is used, and in the first step, a soft polishing pad is attached to the processing surface to be a polishing tool, and fine particles are used as an abrasive to crystallize with the soft polishing pad. By polishing both sides of the glass substrate at the same time, in the second step, a hard polishing pad is attached to the processing surface that will become the polishing tool, and fine particles are used as an abrasive, and the hard polishing pad crystallizes. By polishing the both sides of the glass substrate at the same time, the magnetic film in the magnetic disk substrate having the features according to patent claim 1, the protective film manufacturing method of a magnetic disk, characterized in that the formation of the lubricating film. 16. A combination of a soft polishing pad and fine particles, in which fine particles are scattered on a smooth surface of an amorphous chemically strengthened glass substrate or a single crystal substrate of silicon or the like, and film growth is performed by using the particles as nuclei. A method of manufacturing a magnetic disk, wherein a magnetic film, a protective film, and a lubricating film are formed on the magnetic disk substrate having the characteristics of claim 1 by a mechanical and chemical polishing method using. 17. A magnetic disk comprising a glass substrate, a single crystal substrate such as silicon, or a sintered substrate such as carbon or ceramics as a substrate material, and a magnetic film, a protective film, and a lubricating film formed on the surface thereof. , The fine particles are scattered on a magnetic film or a protective film, the particles are used as a nucleus for film growth, and a combination of a soft polishing pad and fine particles is used to perform a mechanical-chemical polishing method. A method of manufacturing a magnetic disk having the characteristics according to claim 1. 18. A surface of a crystallized glass substrate is polished by a mechanical polishing method using a combination of a hard polishing pad and fine particles to smooth the substrate surface shape, and then a sliding surface of a magnetic head. The mechanical and chemical polishing method using a combination of a soft polishing pad and fine particles only on the inner peripheral side portion of the contact surface of the magnetic disk, which has the features of claim 1, and has a surface with an uneven surface. A magnetic disk manufacturing method characterized in that a magnetic film, a protective film, and a lubricating film are formed on a magnetic disk substrate having a smooth surface shape on the outer peripheral side. 19. The method according to claim 1, wherein the surface of the crystallized glass substrate is subjected to a mechanical and chemical polishing method using a combination of a soft polishing pad and fine particles, and then: The outer peripheral side of the concavo-convex forming surface is a mechanical polishing method using a combination of a hard polishing pad and fine particles, the substrate surface shape is smooth-polished, and the inner peripheral side of the magnetic disk contact surface in contact with the sliding surface of the magnetic head. A method of manufacturing a magnetic disk, comprising forming a concavo-convex surface only on a part and forming a magnetic film, a protective film, and a lubricating film on a magnetic disk substrate having a smooth surface shape on the outer peripheral side. 20. With respect to the surface of a crystallized glass substrate, an average surface of surface irregularities formed in a data zone for reading and writing data of magnetic recording causes the magnetic head to stop and fly.
In the relative positional relationship with the average surface of the surface irregularities formed on the zone, the average surface of the data zone is relatively higher than the average surface of the CSS zone, and the magnetic surface is A method for manufacturing a magnetic disk, comprising forming a film, a protective film, and a lubricating film. 21. With respect to the surface of a crystallized glass substrate, an average surface of surface irregularities formed on a data zone for reading and writing data of magnetic recording causes the magnetic head to stop and float.
In the relative positional relationship with the average surface of the surface irregularities formed on the zone, the average surface of the data zone is relatively lower than the average surface of the CSS zone, and the magnetic surface is A method for manufacturing a magnetic disk, comprising forming a film, a protective film, and a lubricating film.