JPH08297834A - Magnetic disk - Google Patents

Abstract

PURPOSE: To embody a magnetic disk which has an excellent CSS characteristic in spite of making the flying height of a magnetic head smaller than heretofore and with which a head crash hardly arises and high reliability is obtd. CONSTITUTION: This magnetic disk has magnetic films for recording information formed of thin films, a protective film and a lubricating film on a nonmagnetic substrate. The magnetic disk has projecting parts nearly smoothed in the surface as the magnetic surface characteristics thereof. The load ratio ΔLi at the cut face Δhi (preferably 5 to 10nm from the extreme peak part on the surface of projecting part) of the depth corresponding to the deformation rate at the peak parts from the extreme peak parts on the surface of a three-dimensional curve expressing the surface characteristic of the magnetic disk is specified to 0.1 to 10%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk, a manufacturing method and manufacturing apparatus therefor, and a magnetic disk apparatus, and more particularly to a magnetic disk suitable for a thin-film magnetic metal layer as a recording medium, and a manufacturing method and manufacturing method therefor. The present invention relates to a device and a magnetic disk device.

2. Description of the Related Art In a high-density and large-capacity magnetic disk, a magnetic recording medium formed on a non-magnetic disk substrate is formed by coating a magnetic metal from a so-called coating film obtained by binding conventional magnetic powder with a resin. It has moved to a so-called thin film magnetic metal layer which is directly formed on the substrate as a thin film by vapor deposition, sputtering or the like.

When the magnetic disk drive is driven, a magnetic head (hereinafter simply referred to as "head") having a specific load elastically comes into contact with the surface of a magnetic disk (hereinafter simply referred to as "disk") in a stationary state. It is pressed, and at the start, as the disc rotates,
The head begins to slide on the disk surface, and the rotation speed is several tens of minutes per minute.
When a high speed rotation of 00 rotation is reached, the head floats above the disk surface by a predetermined distance due to the dynamic pressure effect of the air flow generated between the sliding surface of the head and the disk.

In the disk device, the head can be arbitrarily moved in the radial direction of the disk in this floating state, and data reading is performed at an arbitrary position on the disk surface. On the other hand, at the time of stop, the disk starts decelerating rotation, and accordingly, the head again starts to slide on the disk surface, comes into contact with it, and stops in the pressed state.
Such driving method normally contact start stop (C ontact S tart S top, short CSS) is referred to as.

That is, in this CSS drive system, the sliding surface of the head is in the state of stopping the disk surface → sliding → floating → sliding → stopping, and this cycle is repeated each time it is driven. In order to facilitate the floating property of the head, fine grooves are generally formed in the circumferential direction of rotation on the disk surface.

FIG. 10 shows the cross-sectional structure of the disk 80. Normally, this type of groove is subjected to a surface polishing treatment called texturing in advance on the surface of the disk substrate 30 before forming a magnetic film. The thin film magnetic metal layer 32 is further formed on the surface of the substrate having such an uneven surface, and a protective film 33, a lubricating film (not shown) and the like are formed on the thin film magnetic metal layer 32, so that the surface condition of the underlying substrate is improved. The copied groove will be formed on the surface of the disk.

The texture processing of the disk substrate surface is performed by C
This is an important polishing technique in adopting the SS drive method. For example, by setting the maximum surface roughness of the surface irregularities of the disk substrate to 0.02 to 0.1 μm as described in JP-A-62-219227. , The non-magnetic metal film (Cr film) can be thinned to improve productivity, and CS
As a result of the S test, no scratch was found on the disk surface after 20,000 times, but when the maximum surface roughness was 0.1 μm or more, a head crash was likely to occur, and CSS was performed 5000 times without texturing. It is said that scratches were caused after passing and the head crash occurred.

As an example of a conventional texture processing apparatus, there is a technique as shown in FIG. 12 as described in, for example, Japanese Patent Laid-Open No. 54-23294. That is, on both sides of the rotating disk substrate 30, the polishing tapes 4 running vertically as the reel 6 rotates are sandwiched between the contact rollers 8 and pressed in the directions of the arrows so as to slide back and forth in the radial direction of the disk substrate. A device for processing both surfaces of a disk substrate at the same time is known.

7 and 8 show the positional relationship between the substrate 30 and the polishing tape 4 running thereon, FIG. 7 being a front view and FIG. 8 being a side view thereof. It is shown in. According to this type of texturing, a fine groove 37 having no polishing unevenness can be formed by the polishing tape as shown in FIG. 11, but with this formation, an unstable swelling is formed on the shoulder portion of the groove. There is a problem that the portion 36 is formed and the raised portion 36 remains on the surface as a fine protrusion.

Therefore, as can be seen in, for example, Japanese Patent Laid-Open No. 62-248133, a first texturing process is applied to a normal texturing process, and then a second texturing process is carried out using smaller abrasive grains than the first photofinishing process. It has been proposed to remove only the protrusions formed on the substrate surface in the first polishing step without removing fine grooves formed on the disk substrate surface by polishing.

[0011]

As described above, with respect to the fine grooves formed in the disk substrate by the conventional texturing, the maximum surface roughness is regulated and the protrusion on the substrate in consideration of the head floating property is taken into consideration. Regulations are shown, but CS
The optimum surface properties of the textured surface for S characteristics and head adhesion characteristics are still unknown, and problems such as head crash have not been solved yet.

In particular, the recent progress in high density and large capacity of magnetic disks has been remarkable, and accompanying this, the flying height of the head on the disk surface due to CSS has been reduced, while the head has moved to the disk surface due to, for example, disk rotation. A narrower condition is required such that the gap between the disk surface and the head sliding surface in the floating state (so-called flying amount) is 0.2 μm or less.

Therefore, in order to realize this strict condition by the texturing, it is natural that the height of the protrusion raised on the shoulder portion is set to be equal to or less than the floating amount by forming the groove, and the head is lifted when the head is floated. Must be prevented from coming into contact with the protrusion, and extremely strict disk surface properties are required. If the contact between the protrusion and the head sliding surface is simply avoided, it is sufficient to change the shape of the head sliding surface, the head load, the number of rotations of the disk, etc. to secure a sufficient flying height of the head.

However, as described above, the flying height must be reduced as the recording density of the disk device increases (ideally, the head and the magnetic film should be in intimate contact with each other as much as possible). In order to reduce the amount of deformation and the amount of friction and wear of this protrusion, the heights of the protrusions are made uniform, the contact area with the head sliding surface is increased, and sliding debris is also avoided. It is necessary to have deep grooves.

Therefore, as described above, in order to make the heights of the protrusions formed by the groove formation uniform, the polishing process of the disk substrate surface is divided into the first and second two-step processes, and the second process is used. Although it is attempting to polish and align the protrusions with each other, it is unclear about the CSS texture when the flying height of the head is small and the surface texture of the optimum texturing for the head adhesive property, and the problems such as head crash still remain. Not resolved.

That is, if the heights of the protrusions are made uniform by sufficient polishing, the sliding area of the head with respect to the disk surface (strictly speaking, the polishing surface that contacts the head sliding surface of the protrusion) increases. As a result, the flying property of the head is lowered, and the lubricant (generally a lubricating film is formed) on the disk surface and the moisture in the atmosphere adhere to the head sliding surface, and these are accumulated by surface tension, Eventually, the sliding surface of the head is attracted to the disk surface, which causes new problems such as disk incapability and head damage.

Therefore, an object of the present invention is to solve these problems of the prior art. The first object of the present invention is to provide excellent CSS characteristics even if the head flying height is made smaller than the conventional one.
An improved magnetic disk in which head crash is less likely to occur, a second purpose is a manufacturing method thereof, a third purpose is an apparatus for manufacturing the same, and a fourth purpose is to drive the magnetic disk and the magnetic head. It is to provide a magnetic disk device in which the device is integrally mounted.

[0018]

SUMMARY OF THE INVENTION A first object of the present invention is to:
(1) At least a non-magnetic substrate having a finely textured surface processing layer on its main surface, and at least a thin-film magnetic metal layer sequentially formed on the non-magnetic substrate following the irregular surface and its protective layer. In the magnetic disk having the above-mentioned non-magnetic metal substrate surface-processing layer, the surface texture of the convex portion has a convex portion whose surface is substantially smoothed, and in the three-dimensional load curve representing the surface shape, A magnetic disk comprising a non-magnetic substrate having a load ratio of 0.1 to 10% at a cut surface having a depth corresponding to the amount of top deformation received by the head load during CSS from the top, and (2) at least A non-magnetic substrate having a finely textured surface processing layer on its main surface, at least a thin-film magnetic metal layer sequentially formed on the non-magnetic substrate along the irregular surface, and its protective layer. In a magnetic disk having a layer, as the surface texture of the convex portion in the non-magnetic metal substrate surface-treated layer, with a height of several nm to several tens nm and a convex portion whose surface is substantially smoothed, In the three-dimensional load curve showing the surface shape, 5 to 5 from the top of the convex surface
A magnetic disk comprising a non-magnetic substrate having a load ratio of 0.1 to 10% on a cut surface having a depth of 10 nm, more preferably (3) a three-dimensional load of the surface shape in the non-magnetic metal surface processing layer. A magnetic disk having a curved surface having a flat shape on the pole surface, and more preferably (4) the surface texture of the non-magnetic metal substrate surface processing layer has a depth corresponding to the width of the head slider sliding surface. Is achieved by a magnetic disk comprising recessed fine deep grooves of at least 100 nm and R _sk ≤-0.7 indicating the _symmetry of the cross-section curve.

The second object of the present invention is as follows. (1) The surface of a non-magnetic substrate that has been mirror-finished in advance is polished in the first and second two-step polishing steps, so that the surface of the non-magnetic substrate becomes uneven. Manufacturing of a magnetic disk including a step of forming a processing layer, a step of forming a thin film magnetic metal layer on the uneven processing layer formed by the polishing step, and a step of forming a protective film on the thin film magnetic metal layer. In the method, as the first polishing step, a fine groove having a predetermined deep groove as a recess is provided in at least a unit width corresponding to the sliding surface width of the magnetic head on the substrate, and as the second polishing step, The protrusion formed by the formation of the fine groove on the shoulder is polished by a predetermined amount from the top, and when smoothing the surface of the protrusion, the surface shape is detected as the end point detection of the polishing amount from the top. Third order Surface protrusions highest portion is determined load ratio in a cross section of the top part deformation quantity equivalent depth to receive the head load at CSS in load curve, the value is 0.1 to 10
%, Preferably by (2) polishing the surface of the non-magnetic substrate that has been mirror-finished in advance by the first and second two-step polishing steps. By doing so, a step of forming an unevenness processing layer on the surface of the non-magnetic substrate, a step of forming a thin film magnetic metal layer on the unevenness processing layer formed by the polishing step, and a protective film on the thin film magnetic metal layer. In the method of manufacturing a magnetic disk including a step of forming, in the first polishing step, a fine groove having a predetermined deep groove as a recess is formed in a unit width at least corresponding to a sliding surface width of the magnetic head on the substrate. Providing, as the second polishing step, when a convex portion formed on the shoulder portion by the fine groove formation is polished by a predetermined amount from the top thereof to smooth the surface of the convex portion, Of polishing amount As point detection, 5 to 10 nm from the surface of the protrusion highest portion in the three-dimensional load curve representing the surface shape
The load ratio on the cut surface at the depth of is calculated and this value is 0.
According to the method for producing a magnetic disk which is completed by polishing within the range of 1 to 10%, more preferably, (3) the first polishing step is performed on both surfaces of the non-magnetic substrate simultaneously with the first polishing tape. While pressing with a predetermined first pressure, the polishing tape is run in the circumferential direction of the non-magnetic substrate and is reciprocated while being swung in the radial direction to supply the working liquid to the polishing surface, The non-magnetic substrate is processed by rotating the non-magnetic substrate so that the relative speed to the first polishing tape becomes a predetermined first relative speed, and then washed, and then as the second polishing step. At the same time, a second polishing tape having an abrasive grain size smaller than that of the first polishing tape is pressed against both surfaces of the non-magnetic substrate with a second pressing force smaller than the first pressing force. Run in the circumferential direction of the non-magnetic substrate Together it is, is reciprocated while being swung radially, while supplying a machining fluid to the polishing surface,
The non-magnetic substrate is processed by rotating the non-magnetic substrate so that the relative speed to the second polishing tape becomes a predetermined second relative speed which is higher than the first relative speed, and then the non-magnetic substrate is cleaned. This is achieved by the method for manufacturing a magnetic disk configured as described above.

A third object of the present invention is to provide a substrate support tool capable of rotatably supporting a disk substrate, and to simultaneously perform the first polishing process on both surfaces of the substrate.
A contact roller unit capable of pressing the polishing tape with a predetermined pressure, a tape winding motor for winding the polishing tape, and the contact roller unit can be swung in the radial direction of the substrate. A first processing head having a reciprocating means, and a second processing head having the same structure as the first processing head disposed on the opposite side of the substrate support for performing the second polishing processing; Substrate rotating means capable of rotating the substrate so that the relative speed of the substrate to the polishing tape becomes a predetermined value, and substrate cleaning means disposed between the both processing heads and capable of cleaning the substrate. And a controller for controlling the operation timing of at least the processing heads and the substrate rotating means, at least. More, it is achieved.

The fourth object of the present invention is as follows.
(1) A plurality of magnetic disks are mounted on the same rotary shaft at predetermined intervals, and a head slider having a magnetic head mounted on at least one surface of each of the disks is fixed in a stationary and initial rotating state of the disk. CSS that elastically contacts and slides with the pressing force of the disk, floats by high-speed rotation of the disk, and reciprocally drives in the radial direction of the disk.
In a magnetic disk device equipped with a head drive device for recording and reading information by a drive system, the surface texture of the magnetic disk sliding surface in relation to the magnetic disk and a head slider slidingly floating on the disk is non-magnetic. It has a surface texture that follows the surface condition of the uneven processing layer on the surface of the magnetic disk substrate made of a substrate, and the surface texture of this disk substrate has a convex portion whose surface is substantially smoothed, and 3 In the dimensional load curve,
The load ratio from the top of the surface to the cut surface at a depth corresponding to the amount of top deformation received by the head load during CSS is 0.1 to 10
%, And preferably (2) as a property of the surface of the disk substrate, a convex portion having a height of several nm to several tens nm and having the surface smoothed. And a non-magnetic substrate having a load ratio of 0.1 to 10% in a cross section having a depth of 5 nm from the top of the convex surface in a three-dimensional load curve representing the surface shape. , And more preferably,
(3) A magnetic disk device having a three-dimensional load curve as a characteristic of the surface of the disk substrate having a flat shape on the extreme surface, and more preferably (4) a head slider as the characteristic of the surface of the disk substrate. Even more preferably, a magnetic disk drive comprising concave fine deep grooves having a depth of at least 100 nm within the width of the sliding surface and R _sk ≦ −0.7 indicating the _symmetry of the cross-sectional curve, (5) When the contact area between the head slider and the disk surface is S, the surface pressure W / S when the head load is W, and the yield strength of the fine protrusions on the disk substrate surface by CSS driving is σ, the disk of the head slider is The initial state on the sliding surface is σ ≧ W
This is achieved by a magnetic disk device having a disk sliding surface that is in a contact state that maintains the relationship of / S.

Here, the results of the study by the present inventors leading to the present invention will be described in detail below.

The CSS causes the outermost surface of the disk to change in a dimension of the order of nanometer (nm) due to the sliding of the head slider on which the magnetic head is mounted, and this change smoothes the disk surface and the horizontal resistance force exerted on the head. And the head crashes when the CSS is stopped, or the head sticks when the CSS is stopped, causing an accident such as a disk rotation failure. Therefore, with respect to the processed surface of the disk substrate by texture processing, the maximum surface roughness and the height of the convex portion are simply defined by the CS of the magnetic disk.
It was found that the S characteristics and the sliding resistance characteristics such as head crash cannot be explained. In contrast to the maximum surface roughness, the overall property including the shape of the convex portion from the average surface and the shape of the groove of the surface irregularity, and the property of the three-dimensional load curve are more important as described later. Therefore, no attention has been given to the prior art, and it has been found that the most important presentation has not been made regarding the surface ruggedness of the underlying substrate for which head crash and CSS characteristics should be improved.

The magnetic disk device 85 is generally composed of a plurality of magnetic disks, as shown in the partial sectional perspective view of FIG.
80 are mounted and fixed on the same rotary shaft at predetermined intervals, and magnetic heads 81 for recording and reading information are installed on both sides of each disk. 21 is an explanatory view schematically showing the relationship between the disk 80 and the head 81 (also referred to as a head slider) in the disk device shown in FIG.
The head 81 is fixed to the tip of the arm 84, and when the disk is stationary or in the initial state of rotation, the elastic force of the arm 84 is pressed onto the disk surface to bring it into contact and slide, but the disk rotates at high speed. In this state, the head 81 is in a state of floating with a submicron flying height due to the effect of the air flow with the disk 80.

FIG. 23 specifically shows these states.
23A shows a contact state when the disc is stopped and sliding, and FIG. 23B shows a floating state when the disc rotates at a high speed. The shape of the head 81 has sliders 82 that slide on the disk surface on both sides of the head, as shown in FIG.

As an example of the dimensions of the head slider surface 82, the width w is 0.4 mm and the length l is 4 mm, and the length l (el) direction of this head slider is the same as the circumferential direction of the disk. Is installed as. Therefore, the uneven shape of the disk surface is problematic at least for the head slider width w, that is, a dimension of 0.4 mm or a dimension of 0.4 mm or more.

A method of measuring the cross-sectional shape of the textured substrate surface will be described. This cross-sectional shape is a Talystep surface roughness meter (Rank Taylor Hobson)
Using a stylus whose stylus shape is 0.1 μm × 2.5 μm, the head slider width w
(Eg 0.4mm) or head slider width 0.4
It is a curve measured with a length of mm or more. The output signal from the Taristep is A / D converted, and by computer processing,
The sampling interval was 40 nm.

As shown in FIG. 29, the fine protrusion means the above-mentioned cross section measured in the radial direction of the disk substrate with respect to the textured surface formed in an approximately circumferential direction or in a spiral shape. Regarding the curve, the convex direction from the center line C of the cross-sectional curve, that is, individual peaks having a minute height (referred to as convex portions in the present invention) are shown. Further, the height R _p of the fine projection represents the distance between the highest peak of the individual peaks in the unit length L measured in the radial direction and the center line.

As the surface texture of the textured surface, the symmetry of the texture section curve is represented by R _sk obtained by the following formula according to a well-known display method. If the sectional curve is a function Y (i), it can be expressed by the following general formula.

[0030]

[Equation 1]

That is, when R _{sk indicating} symmetry is negative, the groove component of the cross-sectional curve is large, and when it is positive, the protrusion component is large. When R _sk = 0, it means that the component of the protrusion and the component of the groove are equal, and the sectional curve is symmetrical with respect to the center line C.

Here, a method for three-dimensionally measuring the texture of the textured surface will be described with reference to FIG. FIG. 30A shows an STM (scanning tunnel) described later.
3G shows the result of three-dimensional surface measurement G of the textured surface by a ling Microscope. From this, the three-dimensional surface is cut at a plane H parallel to the average plane (plane from the outermost surface to a depth Δhi) at equal intervals. FIG. 30 (b) is a graph of the area ratio (ΔLi) obtained by dividing these cut areas by the total area of the reference plane E deeper than the uneven processing layer for each cut surface. That is, FIG. 30 (b)
Is a three-dimensional load curve.

This three-dimensional load curve is generally an Abbott load curve, ABBOTT-FIRSTONE (OR BEA, for a two-dimensional sectional curve as shown in FIG.
RING RATIO) It has the same contents as CURVE, but is developed in three dimensions. This Abbott load curve is used to evaluate the sliding characteristics of the bearing and the like. The present inventors have observed the contact phenomenon between the head and the disk in detail with respect to the state of the head sliding surface, the state of the disk surface, and the motion state of the head and the disk in CSS, and as a result of the measurement, As a method to evaluate the disk surface with high accuracy for sliding characteristics such as STM
It has been found that the three-dimensional load curve according to Eq.

That is, this load curve is shown in FIG.
As shown in (a) and (b), the surface shape is cut at regular intervals from the top of the three-dimensional shape with respect to the reference area E of the three-dimensional shape G on the surface, and the three-dimensional shape by the cut surface H is obtained. A curve obtained by dividing the sum of the respective cut areas by the reference area E in each cut surface is shown. At the top of the surface shape, the cut area by the cut surface is small, and the cut area ratio is small. That is, if there is a sliding body on this surface, since the sliding body is supported only by the top portion of the surface shape at the initial stage of sliding, the pressure receiving area is small and the surface pressure is large, so the sliding portion causes the top portion to frictionally slide. , Wear and deformation easily occur.

Therefore, on the surface having a large cutting area ratio at the top of the surface shape, that is, in the three-dimensional load curve, in the range where the cutting area ratio is small, the surface showing the surface shape with a small gradient of the load curve shows the pressure receiving area. Large in the initial state,
Since the surface pressure of each fine protrusion that supports the sliding body is reduced, the sliding resistance is improved. As described above, the three-dimensional load curve is one of the evaluation methods that express the load capability with respect to the surface texture of the surface to be slid on the sliding body.

As a method for measuring the three-dimensional surface of the textured surface, SEM (Scanning Electron Microscope) is used.
FIG. 24 shows the measurement principle to which is applied. That is, to explain according to the figure, the two secondary electron detectors A and B detect the signal intensities a and b at the incident angle θ (inclination of the sample) of the electron probe, and the incident angle 0 (on a plane) is detected. (Irradiation) as the signal intensity an, bn

[0037]

## EQU2 ## θ is calculated from tan θ = k {(a ² −b ² ) / (an + bn) ² }, where k is a constant. By integrating the inclination of the sample thus obtained, the surface shape in the X-axis direction can be measured. For example, an electron beam surface morphology analyzer manufactured by Elionix Inc. can be cited as this type of measuring device. Furthermore, if scanning in the Y direction, the shape of the three-dimensional surface can be measured.

The present invention has been made on the basis of the above findings. The details of the study will be described in more detail below. As is well known, the substrate of the magnetic disk is a non-magnetic substrate such as an aluminum alloy, anodized aluminum, or an aluminum alloy coated with Ni-P plating,
Further, it is necessary to form a large number of uniform fine grooves and fine protrusions on the surface of the substrate, which is made of a substrate such as glass or plastic and is one factor for improving the characteristics.

These fine grooves and fine protrusions are formed on the surface of the substrate with a cutting and polishing tool such as a diamond bite or fine abrasive grains so that the shoulders of the groove portions are shown in FIG. The raised portion 36 is formed. The rising height of these fine protrusions is set by the depth and size of the groove 37, and the number of fine grooves is set by the processing conditions such as the density of fine abrasive grains and tool feed.

Here, the essential point as the surface properties of the magnetic disk is that head crush does not occur and that various characteristics of the magnetic disk such as electric characteristics, CSS characteristics, and head adhesion characteristics are satisfied. In order to achieve a high density of the magnetic disk, the head flying gap is narrowed, so that the disk surface is required to have an ultra-smooth surface in order to avoid collision between the head and the disk.

On the other hand, since it is necessary to shorten the head access time, the head 81 and the disk 80 are in contact with each other at the time of stop as shown in FIG. 23 and float with the rotation of the disk, so-called contact start stop (hereinafter referred to as C).
Abbreviated as SS). Therefore, when the surface of the disk 80 is a smooth surface, that is, the surface roughness is very small, the head and the disk are adhered to each other by the lubricant 83 on the disk surface or moisture in the atmosphere when the disk is stopped, and the head is supported when the disk is rotated. There was a problem that the gimbal and arm were damaged and could not be rotated.

The results of experiments conducted by the present inventors are shown in FIGS. 13, 14 and 32. The height of the fine projections, the symmetry of the texture section curve, and the three-dimensional section load ratio, the head flying characteristics, and the head adhesiveness, which are formed by the texture processing (details will be described later) formed on the base substrate using the polishing tape. Shows the relationship.

That is, FIG. 13 shows the relationship between the protrusion height, the head flying height H _t0 as the flying characteristic, and the head tangential force F _t as an index of the head adhesive force, and FIG. 14 shows the symmetry R _sk.
FIG. 32 shows the relationship between the three-dimensional sectional load ratio (at the tangential sectional depth of 5 nm from the top) and the flying height H _t0 and the head tangential force F _t , respectively. The method is as follows.

(1) Measurement of head flying height H _t0 : In principle, the head has the same structure as the disk device 85 of FIG. 20, an AE sensor is mounted on the head 81, and when the disk 80 starts rotating. , The head 81 starts to float, and the disk rotation speed at which the output signal from the AE sensor detecting the contact state with the disk surface sharply decreases is measured. On the other hand, the flying characteristics of the head depending on the number of revolutions of the disk are previously checked, and the flying start height H _t0 of the head is measured.

(2) Measurement of head tangential force F _t : The sliding resistance force of the head during one revolution (1 _r / min) of the disk is measured by a strain gauge installed on the support arm 84 of the head 81.

From this result, there is an effective range of surface properties suitable for simultaneously satisfying both the head flying characteristic and the head adhesiveness, that is, the flying height H _t0 is small and the tangential force F _t is small. Recognize. That is, as shown in FIG. 13, the small protrusions R _p are preferably in the range of several nm to several tens of nm, more preferably in the region indicated by the arrow, and the symmetry R _sk is shown in FIG. A negative region, preferably a region of R _sk ≦ −0.7 indicated by an arrow is desirable.

As for the relationship with the three-dimensional cross-section load ratio, as shown in FIG. 32, the lower limit of the effective load ratio is from the flying characteristics, and the upper limit is the head adhesive force (indicated by the head tangential force F _t ). It was regulated by 0.1 to 10%, more preferably 0.24 to 8.5%.

Further, the relationship between the above surface texture and CSS characteristics will be described with reference to FIGS. 27 to 28. Figure 2
7 (a) shows the cross-sectional shape of the surface of the underlying substrate that is textured using fine abrasive grains, and fine protrusions are present with variations.

As shown in FIG. 27 (b), the three-dimensional load curve of this textured surface shows that the gradient of the load curve is in the range where the cutting area ratio is small, that is, in the range of part A in FIG. 27 (b). large. When the magnetic head repeats CSS on the surface as shown in FIG. 27 (a), the fine protrusions are less in contact with the head slider surface, so that the surface pressure W / S (W: head load, S: head slider). The actual contact area between the disk and the disk surface) becomes large, resulting in severe wear or deformation, and the number of thicknesses formed on the underlying substrate on which minute protrusions are formed.
The lubrication film with a thickness of 10 nm and the protective film with a thickness of several 10 nm are greatly damaged.

On the other hand, the wear or deformation of the fine protrusion due to CSS is σ <W /, where σ is the yield strength of the fine protrusion.
In the state of S, it occurs violently and decreases in the state of σ ≧ W / S. Therefore, the wear and deformation of the fine protrusions caused by CSS increases the true contact area, resulting in the true contact area S satisfying the above σ ≧ W / S. If it is formed without being damaged, wear and deformation of the fine protrusions are almost eliminated, and a stable surface is obtained.

Therefore, the underlying substrate having the cross-sectional shape shown in FIG. 27A is further surface-processed to form a model trapezoidal shape in which fine protrusions as shown in FIG. 28A are smoothed. . If the true contact area between the head slider and the disk surface is increased to make the surface shape of the true contact area such that σ ≧ W / S in the initial state, the surface pressure of the fine projection becomes small. Almost no wear or deformation is obtained, and a stable and highly reliable surface can be obtained as a magnetic disk. The surface shape 3 shown in FIG.
The dimensional load curve is as shown in FIG.
It can be seen that the slope of the load curve on the pole surface is very small, as shown in part A of (b).

In the experiments conducted by the present inventors, a conventional textured surface having a three-dimensional surface shape as shown in FIG. 27 (a) corresponds to the head slider surface (for example, 0.4 mm × 0.4 mm). 3D load curve on the surface) is 5 nm to 10 nm from the top of the surface shape, that is, the cut area ratio at the cut surface depth of 5 nm to 10 nm is 0.1% or less, and such a base substrate was used. In the magnetic disk, head crash occurred when the CSS number was 2000 times or less.

On the other hand, the texture-processed material of the present invention, as shown in FIG.
The surface as shown in 8 (a), that is, the depth of the cut surface is 5 nm
In a magnetic disk using a base substrate having a three-dimensional load curve surface with a cutting area ratio of 0.1 to 10% at ~ 10 nm, the protective film and lubricating film maintain their respective functions when the CSS count is 20000 or more. However, the surface condition was stable.

Further, detailed changes of the magnetic disk surface due to CSS were examined. In the experiments conducted by the present inventors, the contact start / stop CSS test was performed on the textured substrate.
From the surface shape measured from the SEM observation of the disk surface subjected to the SS test, and from the three-dimensional load curve of the disk pole surface shown in FIG. 16, the top of the fine protrusion in the initial state was smoothed by repeated sliding of the magnetic head. It has been found that the area of the fine protrusions in contact with the head and the disk at this time increases.

That is, FIG. 15 (a) shows the surface shape in the initial state, and FIG. 15 (b) shows the state after the surface has been deformed by repeated sliding by CSS. Further, the load curve B in FIG.
The characteristics of (a) in the initial state, and the load curve A
Shows the characteristics after repeated sliding in FIG. 15 (b).

Here, for example, the change of the surface when the number of CSS times is 20,000, the height from the top in the initial state is 5 to 5 due to the contact with the slider surface of the magnetic head as shown in part A of FIG. 15 (b). If the fine protrusion changes by 10 nm and the fine protrusion changes from the top of the initial state by 5 to 10 nm from the three-dimensional load curve of the disk surface at this time shown in FIG. 16, the cutting area contact with the magnetic head becomes 0.1. It was about a few percent to a few percent.

That is, if the height of the fine protrusions is several tens of nm or more, the flying characteristics of the magnetic head are deteriorated, which causes a head crash, and even if the fine protrusions are several nm or less, the cutting area is small. When the ratio is small, the substrate surface that supports the head load when the head is slid in the CSS test, that is, the load area of the fine protrusions is small, the surface is smoothed immediately with CSS times, and the head tangential force increases, causing a head crash. Is likely to occur.

Further, when the load area of the fine protrusions is small, the surface pressure of the fine protrusions which receives the head load becomes large, so that the fine protrusions are easily reduced or worn, and the lubrication of several nm formed on the substrate surface is performed. If the agent layer or the protective film layer is easily damaged, and if the cutting area ratio is 10% or more and the load area is large, the change of the fine protrusions on the substrate by the magnetic head is small, but the contact area becomes large. Head adhesion is likely to occur due to the influence of the lubricant and moisture in the atmosphere, and the sliding resistance of the magnetic head during CSS increases, causing problems such as gimbal and arm destruction of the magnetic head, and difficulty in rotating the disk.

Therefore, the surface texture of the textured substrate takes into consideration the flying characteristics of the head, the head load, and the surface change due to frictional wear caused by head sliding. Surface roughness of several tens of nm
nmR _a to several tens of nmR _a , and the symmetry R _{sk of the} cross section curve is negative,
The surface is preferably -0.7 or less, more preferably -1 or less, or, in a three-dimensional load curve, a cut surface at a depth corresponding to the amount of top deformation received by the head load during CSS from the top of the fine protrusion, practical. 5-10 nm from the top
A surface having a cutting area ratio of 0.1 to 10% is desirable.

From this point of view, the optimum surface for the magnetic disk substrate is, as shown in FIG. 6, a pseudo circumferential fine groove formed on the substrate surface, that is, a textured cross section of the substrate surface. The shape is such that the height of the fine protrusion is several nm to several tens.
nm and uniformly smoothed, and the surface roughness is several nm _Ra to several tens n.
mR _a (preferably 5 nm to 9 nm _Ra ), and the symmetry of the cross-section curve R _sk ≦ -1, the cutting area ratio at the top 5 to 10 nm is 0.1.
~ 10%.

Further, in order to maintain the smooth head sliding on the disk, in the case where the deep groove V as shown in FIG. It is important that the groove V always exists within the width, and it has been found that it is effective if the depth of the deep groove V is at least 100 nm.

[0062]

[Function] The height of the fine protrusion formed on the magnetic disk substrate is several nm to several tens nm, and the surface roughness is several nm _Ra to several tens nm.
On the surface of _Ra , and the symmetry _{Rsk of the} cross-section curve is -0.7 or less, preferably -1 or less, especially on a three-dimensional load curve, the amount of top deformation corresponding to the top load received by the head load during CSS from the top of the fine protrusions. A cut surface at a depth, practically, a disk surface having a surface texture with a cut area ratio of the cut surface of 5 to 10 nm from the top being 0.1 to 10% is the same as the slider surface of the head during CSS of the magnetic head. Contact and receive a preferred head load.

Further, the surface irregularities of the disk surface retain the lubricating film applied on the surface of the magnetic disk and at the same time prevent adhesion with the magnetic head, and slide debris generated by sliding of the head in the deep groove of the disk surface. There is an action to avoid. Further, since a large number of fine protrusions are in contact with the head slider surface, and the cutting area ratio is 0.1 to 10% at 5 to 10 nm which is practically preferable from the top where surface change due to head sliding occurs,
The surface pressure of the individual fine protrusions becomes small, and changes in the fine protrusions due to repeated CSS, that is, deformation and wear are small, and the surface texture in the initial state is maintained. Furthermore, the height of the fine protrusions is several nm to several tens of nm, which is extremely small compared to the flying gap of the magnetic head (the gap between the magnetic head and the magnetic disk surface in the steady state) of 150 to 250 nm. Even if the assembling accuracy, the rotation accuracy, and the floating fluctuation of the magnetic head are taken into consideration, the magnetic head floats with a sufficient margin, and the head crash due to the collision of the magnetic head does not occur.

Therefore, the protective film and the lubricating film having a thickness of several nm formed on the surface of the magnetic disk are hardly worn or damaged, head adhesion does not occur, and head tangential force does not increase due to repeated CSS. It is possible to obtain a magnetic disk having high reliability with respect to head flying characteristics and sliding resistance characteristics.

[0065]

【Example】

<Example 1> A disk substrate having an inner diameter of 40 mm and an outer diameter of 130 m
Aluminum alloy plate of m is used.
After P-plating and smooth polishing to _a surface roughness of 2 to 3 nm _Ra or less, _a groove shape is formed by a polishing tape as shown in FIG. Number 10
The surface roughness was 5 nm to 8 nm _Ra , and the cross-sectional curve symmetry R _sk was -1 to -2. The cross-sectional shape in FIG. 17 was measured by using a surface roughness meter Taristep and measuring with a stylus shape of 0.1 × 2.5 μm in a direction perpendicular to the groove. A specific method of manufacturing these disk substrates will be described later in detail.

As shown in the sectional structure of the magnetic disk in FIG. 9, the thickness of the disk substrate thus obtained is about
300 nm of Cr-based non-magnetic metal base film 31 and 60 nm of Co
-Ni-based magnetic thin film media 32 are sequentially formed by sputtering, respectively, and a carbon protective film 33 having a thickness of about 50 nm is further formed.
Then, a lubricating film 34 was sequentially formed on it.

As shown in FIG. 18, the surface shape of the magnetic disk thus manufactured is almost the same as that of the disk substrate of FIG. 17, and the surface roughness is 5.5 nmR.
_a (5.3 nm _Ra on the substrate), the height R _p of the fine protrusion is 19 nm
(At the same 20 nm), and the symmetry R _sk of the cross-sectional shape was almost the same.

As with the magnetic disk device 85 shown in FIG. 20, a plurality of magnetic disks are incorporated, and the head floating clearance is 0.2 μm.
As a result of the flying test, the contact between the head and the disk surface was not detected, good flying characteristics were exhibited, and almost no change in the magnetic disk surface shape due to the number of CSSs was observed.

FIG. 19 is a characteristic curve diagram showing the relationship between the number of CSSs and the head tangential force (unit: Newton N) in this embodiment in comparison with the conventional comparative example. The curve C is the present example and the curve D is the comparative example. As is clear from this figure, in the case of the present example, the head tangential force hardly increases even with 30,000 CSS times, and there is also a problem of head adhesion. It did not occur, and the reliability of the magnetic disk and the magnetic disk device could be greatly improved.

As a comparative example, as shown by the curve D, in the magnetic disk in which the fine groove of the cross-sectional shape as shown in FIG. 5 is formed on the underlying substrate by the conventional technique, the head tangential force D increases with the number of CSSs, and the magnetic head There were problems such as damage and head crash. Further, it can be seen that the cross-sectional shape of the disk surface changes remarkably with the number of CSSs as compared with the present invention.

Here, the method of manufacturing the substrate of the present embodiment will be specifically described below. A Ni-P plated film having a thickness of 10 μm was formed on both surfaces of an aluminum alloy disk substrate by an electroless plating method, and smooth-polished to a surface roughness of 0.01 μm R _max or less. Then, as a first polishing step, surface processing is performed with a polishing tape of alumina abrasive grains having a grain size of # 3000 to form fine grooves on the surface of the Ni-P plated substrate.

This surface processing method is disclosed, for example, in Japanese Patent Laid-Open No. 54-2329.
As shown in No. 4, the polishing tape 4 is pressed by the contact rollers 8 on both surfaces of the substrate 30 shown in FIG. 12, the polishing tape is wound on the reel 6 while rotating the substrate, and the polishing tape is By reciprocally sliding on the substrate so that it slides over the entire surface, fine grooves approximately circular or spiral are formed on both surfaces of the substrate.

Next, on the surface of the substrate, abnormal fine protrusions having a height of 100 nm or more are formed at several places, especially in the shoulder portion of the deep groove, which is a cause of deterioration of the head flying characteristic and further head crash accident. It becomes a factor. Therefore, in the second polishing step, a surface treatment was performed in the same manner as in the first polishing step, using a polishing tape having a smaller grain size than the polishing tape in the first polishing step. As a result of the surface processing of the second polishing step, the height of the abnormal fine protrusions is reduced, the tops of many fine protrusions are smoothed, and the fine protrusions H are smoothed as shown in FIG. Moreover, it was possible to form a surface having a cross-sectional shape in which deep grooves V were formed periodically.

During the first and second polishing steps,
A substrate surface cleaning step was provided in order to remove stains on the surface of the substrate such as processing scraps resulting from the surface processing in the first step. In the second polishing step, as a means for detecting the polishing end point, the above-mentioned three-dimensional load curve is obtained based on the principle of SEM in FIG. 24 and the load curve by STM shown in FIG. The point where the cutting area load ratio obtained by cutting at a depth of 5 to 10 nm from the top was 0.1 to 10% was determined as the end point.

<Embodiment 2> An embodiment of a texture processing apparatus for the surface of a disk substrate suitable for manufacturing the magnetic disk of the present invention will be described below with reference to the drawings.

(1) Description of processing apparatus configuration: FIG. 1 is a front view showing an embodiment of an apparatus for texturing a substrate surface according to the present invention, and FIG. 2 is a plan view showing a main part of this apparatus. Three
FIG. 4 is a front view showing details of the substrate cleaning means in FIG. 1, and FIG. 4 is a side view of the substrate cleaning means.

First, an outline of this substrate processing apparatus is shown in FIG.
Explaining using (a), this apparatus is a substrate support 1 capable of rotatably supporting a substrate 2 which is a workpiece, and a first polishing tape 4 on both sides of the substrate 2 at a time. Set of contact roller units C capable of being pressed by the pressing force, a tape winding motor 7 for winding the first polishing tape 4, and the contact roller unit C swinging in the radial direction of the substrate 2. A first processing head disposed on one side of the substrate support, which has a swinging means W capable of moving and a reciprocating means R capable of reciprocating the contact roller unit C in the radial direction of the substrate 2. H1 and the first processing head H1 have the same configuration, and are arranged on the side opposite to the first processing head H1 with respect to the substrate support, and instead of the first polishing tape, they are more abrasive. 2nd small particle size A pair of machining heads of a second machining head H2 Metropolitan wearing the tape, the substrate 2
Is disposed between both the processing heads and the substrate drive motor 3 relating to the substrate rotating means that can rotate the relative speed of the first and second polishing tapes at a predetermined value. This is a substrate processing apparatus including a substrate cleaning means S capable of cleaning, both the processing heads H1 and H2, a substrate drive motor 3, and a controller 17 capable of controlling the substrate cleaning means S. It should be noted that FIG. 1B is an enlarged view of a main part mainly including the first head H1 of FIG.

Further, the above processing head H1 will be described in detail with reference to FIG. 2A which is an enlarged plan view of a main part thereof and a plan view (including a partial cross section) of the main part. The processing head H1 moves a pair of parallel leaf springs 10 and 11 supported by the reciprocating means R so as to be movable in the axial direction of the substrate 2, and the parallel leaf springs 10 and 11 to move the polishing tape 4 Pressurizing and moving means 23 that eliminates the influence of back tension due to winding and enables setting of a predetermined minute pressing force, and corrects minute fluctuations of the pressing force due to the influence of the substrate shape accuracy during substrate processing with good responsiveness. Attached to the parallel leaf springs 10 and 11 and the pressing force correction means 50 (for example, a piezoelectric actuator or the like), which are installed on both sides of the substrate 2 and whose central axes are attached in the radial direction of the substrate 2. Contact rollers 8 and 9, a polishing tape driving device 7 attached to the reciprocating means R and sliding the polishing tape 4 between the substrate and the contact roller, and the parallel leaf spring 10.
A stress measuring means (12, 13) attached to the (11) and a control device (17) for controlling the pressure moving means (23) and the pressing force correcting means (50) according to the output of the stress measuring means are provided.

Therefore, in this substrate processing apparatus, the fluctuation of the back tension due to the winding of the polishing tape, which is a slight fluctuation factor of the applied pressure, that is, the diameter of the polishing tape wound around the supply and winding reels 5 and 6 is reduced. The pressure changes as the tape tension changes as the tape is processed. This variation is always measured by the stress measuring means 12, and if the parallel leaf springs 10 and 11 are adjusted by the pressure moving means 23 according to the variation, the contact roller is irrespective of the variation in the tension of the polishing tape. The pressure applied to the substrate 2 by 8 and 9 can be made constant. Further, in order to improve the responsiveness of the correction of the pressing force with respect to the waviness in the circumferential direction of the substrate during the processing and the fluctuation of the pressing force due to the warp in the radial direction of the substrate, the pressing force correction means 50 such as a piezoelectric actuator is used. A minute pressing force can be corrected with good response. With the above functions, it becomes possible to form fine grooves with high precision.

The first processing head H1 is disposed on one side of the substrate support 1 (right side in FIG. 1A),
It is used to form fine grooves (for example, fine grooves having a depth of about 0.1 μm) on both surfaces of the substrate 2 in the first polishing process. This processing head H1 is a set of two contact roller units C arranged so as to come to both sides of the substrate 2.
A tape winding motor 7a for winding the first polishing tape 4 mounted on each of the above from the lower side to the upper side, and a swinging means W capable of swinging the contact roller unit C in the radial direction, and reciprocating in the radial direction. And a reciprocating means R that can be moved.

Each of the contact roller units C applies a predetermined pressure force to the contact roller 8 via the contact roller 8 used to press the first polishing tape 4 against the substrate 2 and the parallel leaf spring 10. And the parallel plate spring.
A strain gauge 12 for detecting a pressing force is adhered to the pressing member 10. The pressing motor 14 is loaded with the pressing force by displacing the parallel leaf spring 10 in a direction perpendicular to the surface of the substrate 2. Can press force compensation piezoelectric actuator 50
Is capable of correcting minute fluctuations in pressing force during processing with good responsiveness.

The swinging means W comprises a swinging motor 16 and a crank 55 that connects the shaft of the swinging motor 16 and the first machining head H1. Further, the reciprocating means R controls the rotation of the reciprocating motor 15 to the first machining head H.
The screw is transmitted to 1 to reciprocate the machining head.

The second processing head H2 has the same structure as that of the first processing head except that the second polishing tape is mounted instead of the first polishing tape, as described above, and supports the substrate. It is disposed on the other side of the tool (left side in FIG. 1A) and is used for the second polishing step for removing the protrusions of the fine grooves formed on both sides of the substrate by the first processing head. It is something.

Further, the structure of the processing head will be described in detail with reference to FIG. 1 is a rotating shaft for mounting a substrate horizontally installed, 2 is a substrate which is a workpiece, 3 is a drive motor for rotating the rotating shaft, 21 is a screw rotatably supported, and 15 is a screw 21 Reciprocating motor for
Reference numeral 22 denotes a reciprocating carriage supported so as to be movable in the radial direction of the substrate, that is, the direction of arrow A. The reciprocating carriage 22 is provided with a female screw, and the female screw is screwed into the screw 21. ,
The motor 15 constitutes the reciprocating means R. Reference numeral 23 is a moving body supported by the reciprocating carriage 22 so as to be movable in the direction of arrow A, 16
Is a vibrating device fixed to the reciprocating carriage 22, and the vibrating device 16 vibrates the moving body 23 with a minute amplitude.

More specifically, referring to FIG. 2, 24 is a screw rotatably supported by the moving body 23, 14 is a pressurizing motor for rotating the screw 24, and 10 and 11 are the moving body 23 and the substrate 2. A pair of parallel leaf springs movably supported in the axial direction of arrow B, that is, the direction of arrow B, is provided with a female screw on the support base 51 of the parallel leaf springs 10 and 11, and the female screw is screwed into the screw 24. In addition, the screw 24 and the motor 14 constitute a pressure moving means.

Further, when the undulation in the circumferential direction or the warp in the radial direction of the substrate is bad, the applied pressure fluctuates during processing.
For this reason, the parallel leaf springs 10 and 11 are installed on the support base 51 provided with the pressure correction piezoelectric actuator 50, the support base 51 is provided with a female screw, and this female screw is screwed into the screw 24 as described above.

Reference numerals 8 and 9 denote contact rollers rotatably attached to the parallel leaf springs 10 and 11. The contact rollers 8 and 9 are provided on both sides of the substrate 2 and have central axes directed in the radial direction of the substrate. ing.

18a and 18b are braking torque motors attached to the moving body 23, 5a and 5b are supply reels attached to the output shafts of the motors 18a and 18b, and 7a and 7b are windings attached to the moving body 23. Motors, 6a and 6b are motors 7a and 7b
The take-up reels 4a and 4b attached to the output shaft of the are polishing tapes in which fine abrasive grains such as diamond abrasive grains and alumina abrasive grains are adhered and held by a binder such as a resin to a substrate such as a polyester film. Both ends of the tapes 4a and 4b are fixed to the supply reels 5a and 5b and the take-up reels 6a and 6b, and the motors 18a and 18b, the supply reels 5a and 5b,
The motors 7a and 7b and the take-up reels 6a and 6b constitute a polishing tape driving device, and the polishing tapes 4a and 4b pass between the substrate and the contact roller.

Reference numerals 12 and 13 are strain gauges attached to the parallel leaf springs 10 and 11, 17 is a control device for controlling the motors 3, 14, 15 and the like. The control device 17 responds to the outputs of the strain gauges 12 and 13. The parallel leaf springs 10 and 11 are moved by controlling the motor 14 and the pressurizing force correction piezoelectric actuator.

Next, the substrate cleaning means S in FIG. 1A will be specifically described below with reference to FIGS. 3 and 4. FIG. 3 is a front view for explaining the main part, and FIG. 4 is a side view thereof. The substrate cleaning means includes a rotary scrubber (made of brush or sponge) 61 that simultaneously cleans both sides of the substrate, and a scrubber drive motor M that rotates the rotary scrubber 61.
, An air cylinder (not shown) capable of reciprocating the rotary scrubber between a broken line position 61 'and a solid line position, and a liquid tank 65. Reference numeral 60 is a supply unit that supplies the processing liquid and the cleaning liquid.

(2) Description of the operation of the above apparatus: First, referring to FIG.
The substrate 2 is attached to the substrate support 1 of the processing apparatus of (a). Processing conditions such as a pressing force, a relative speed, a vibration amplitude, and the number of reciprocations are set in the control device 17 in order to carry out the first polishing process.

Here, when the substrate processing apparatus is turned on, the substrate is rotated by the motor 3, and at the same time, the first processing head H1 is oscillated by the oscillating motor 16 at the set oscillation amplitude, and the polishing tape driving device 7 When the polishing tapes 4a, 4b are wound with a constant force with the pressure applied to the substrate to be the set first pressure, and the reciprocating means R reciprocates the reciprocating table 22, the polishing tape Fine grooves are formed on the surface of the substrate 2 by 4a and 4b. During this period, the rotation speed of the substrate 2 is controlled by the substrate drive motor 3 to
The relative speed with respect to the polishing tape 4 is adjusted to be the set first relative speed. While the processing is proceeding in this way, the processing liquid is continuously supplied from the supply unit 60 to the substrate.

Even if the tension of the polishing tapes 4a and 4b fluctuates and the parallel leaf springs 10 and 11 are deformed, the control device
Since the motor 17 controls the motor 14 according to the outputs of the strain gauges 12 and 13, that is, according to the deformation amount of the parallel leaf springs 10 and 11, the parallel leaf springs 10 and 11 have the polishing tape 4a,
Contact roller 8, regardless of the fluctuation of tension in 4b,
Since the pressing force of the substrate 9 on the substrate 2 can be made constant, a minute pressing force can be always maintained, so that small and uniform fine grooves can be formed.

Further, with respect to the fluctuation of the pressing force due to the rotation of the substrate 2 and the fluctuation of the pressing force due to the sliding of the processing head in the radial direction of the substrate 2, that is, the substrate 2
The pressing force fluctuates due to the influence of the circumferential waviness, the straightness in the radial direction, and the warp. However, in response to these, the amount of fluctuation of the pressing force is immediately corrected by the command of the control device 17 to correct the pressing force. Can be corrected by.

When the first machining head reciprocates a set number of times, the machining head H1 retracts (moves to the right in FIG. 1), and the supply of machining fluid from 60 is stopped.

Next, as shown in FIGS. 3 and 4, the rotary scrubber 61 'that was at the broken line position rises to 61, which is the solid line position, and the scrubber drive motor M drives this rotary scrubber 61'.
61 rotates. The substrate 2 also rotates, the cleaning liquid is supplied from the supply unit 60, and the substrate 2 is cleaned. When this cleaning is completed, the rotary scrubber 61 descends to the broken line position 61 ', and the supply of the cleaning liquid is stopped.

Then, in order to carry out the second polishing step, the second processing head H2 arranged on the side opposite to the first processing head H1 is moved forward through the substrate support 1 of FIG. 1 (a). , The first processing head H by this processing head
The substrate 2 is processed in the same manner as 1.

That is, at the same time when the substrate is rotated by the motor 3, the second processing head H2 is oscillated by the oscillating motor 16 at a set oscillating amplitude, and the polishing tape drive unit 7 applies a constant force to the polishing tapes 62a and 62b. And the pressure applied to the substrate is adjusted to the set second pressure, and when the reciprocating table 63 is reciprocated by the reciprocating means, the tapes 62a and 62b are applied to the surface of the substrate 2. The existing fine protrusions are removed and smoothed.

During this period, the substrate drive motor 3 adjusts the rotation speed of the substrate 2 so that the relative speed between the substrate 2 and the second polishing tape becomes the set second relative speed. While the processing is proceeding in this way, the processing liquid is continuously supplied from the supply unit 60 to the substrate. Then, when the second machining head H2 reciprocates the set number of times of reciprocation, this machining head retracts (moves to the left side in FIG. 1) and the supply of the machining liquid is stopped. Finally, the substrate 2
When the substrate is cleaned by the substrate cleaning means S, the substrate processing apparatus is turned off.

When the substrate 2 is removed from the substrate support 1, the desired fine grooves are formed. In addition, magnetic media, protective film,
By forming the lubricating film, it is possible to obtain a magnetic disk having excellent sliding characteristics.

(3) Example of substrate polishing by the above apparatus:
A specific example in which fine grooves are formed in the substrate 2 that is Ni-P plated to a thickness of about 10 μm on an Al alloy substrate will be described with reference to FIGS. 5 and 6.

FIG. 5 is an enlarged sectional curve diagram showing an example of the surface texture of the substrate processed by the first processing head H1 (first polishing step) of the substrate processing apparatus according to FIG. 1, and FIG. It is an expanded sectional curve view which shows an example of the surface texture of the board | substrate processed with the processing head H2 of 2nd (2nd polishing process).

The first polishing tape 4 is made of Al ₂ having a particle size of 4 μm.
O ₃ abrasive grain, the first pressure is 10N, the first relative speed is 4m
/ Sec, the oscillation amplitude is 1 mm, the substrate 2 is processed by the first processing head H1 while supplying the water-soluble cutting fluid, and the depth of the surface of the substrate 2 as shown in FIG. V
Although a fine groove of about 100 nm was formed, there was a ridge (fine protrusion) with a height H of about 30 nm, and the ridge height was uneven. The surface roughness is 6～7NmR _a, symmetry R _sk sectional curve was -0.3. Also,
In the three-dimensional load curve, the cut area ratio at the cut surface of 5 nm from the top of the surface shape was 0.1% or less.

A second polishing step was applied after the above first polishing step. The second polishing tape is Al with a grain size of 1 μm
₂ O ₃ abrasive grains, second pressure 4N, second relative speed 8m
/ Sec, the oscillation amplitude was 1 mm, and the substrate 2 washed with pure water was processed by the second processing head H2 while supplying the water-soluble cutting fluid. The surface of the substrate 2 was as shown in FIG. As shown, the depth V of the fine groove was maintained at about 100 nm, the height H of the protrusion was reduced to about 10 nm or less, and the variation was small. The surface roughness is 6～7NmR _a, symmetry R _sk sectional curve was -1.5. In the three-dimensional load curve, the cut area ratio at the cut surface of 5 nm from the top of the surface shape was 0.8%.

According to the embodiment described above, since the second processing head can remove only the raised portion generated in the shoulder portion of the fine groove, the fine groove depth V is 20.
There is an effect that it is possible to form a smooth surface in which the height H of the protrusion (fine protrusion) is reduced to -100 nm.
Furthermore, if the processing conditions such as the grain size of the polishing tape, the material of the abrasive grains, the number of reciprocating slides on the substrate, and the pressing force are changed, any fine groove can be formed.

(4) Application of the above substrate to a magnetic disk:
By applying this method, using the above substrate as a base substrate, as shown in the sectional structure of the disk in FIG.
A thin film magnetic disk 80 in which a non-magnetic metal underlayer film 31, a magnetic medium film 32, a carbon protective film 33 and a lubricating film 34 are formed on 30.
Has good head flying characteristics, and is extremely excellent in reliability and stability.

Various characteristics of the thin film magnetic disk having the fine grooves of the present invention will be described in detail below together with comparative examples. That is, the height of the fine protrusions is several nm to several tens nm, the surface roughness is several nm to several tens nm _Ra , and the symmetry R _{sk of the} sectional curve is negative, preferably -0.7 or less, and more preferably -1 or less. On the surface or in the three-dimensional load curve, a cut surface at a depth corresponding to the amount of top deformation received by the head load during CSS from the top of the fine protrusion, practically 5 to 5 from the top.
A comparison is made between the magnetic disk of the base substrate and the magnetic disk of the other base substrate, which is composed of the surface having a cut area ratio of the cut surface at 10 nm of 0.1 to 10%.

FIG. 25 shows the result of three-dimensional measurement of the textured surface according to the present invention, and FIG. 26 shows the conventional textured surface measured by the same method. What is clear by comparing these figures is that in the case of FIG.
The surface condition is very smooth.

Explaining again with reference to FIGS. 13, 14 and 19, these are texture-processed by variously changing the processing conditions such as the grain size of the polishing tape, the number of reciprocations of the processing head, the pressing force, etc. For non-magnetic metal film, magnetic medium film, carbon protective film and a thin film magnetic disk on which a lubricating film was formed on the underlying substrate whose height and surface properties were changed, the effect on head flying characteristics and head adhesion, Also C
It is the result of examining the influence of the deformation amount of the surface texture (fine protrusion) and the head tangential force by the SS test.

As shown in FIG. 13, when the height of the fine protrusions is several nm (2 to 3 nm) or less, for example, in the case of a base substrate close to the polished surface, the head floating characteristic is good, but the head adhesive force is As a result, the problem of head adhesion increases, the gimbal that supports the head is damaged, and the substrate rotation drive motor is overloaded, resulting in an accident that the substrate cannot rotate.

When the height of the fine protrusions is several tens of nm or more, for example, the fine protrusions are 90 nm or more, the head adhesion is small and the head adhesion problem does not occur, but the head flying characteristics are poor and the head A crash accident occurred. When the height of the fine protrusions was in the range of 3 to 10 nm, the flying height was 0.15 μm, the flying height was stable, and the head adhesion was small, resulting in highly reliable flying characteristics.

As shown in FIG. 14, with respect to the symmetry R _sk , the characteristic is improved in the region where the value is negative, and it is preferably −0.7 or less, practically −1 to −2. Furthermore, the relationship between the three-dimensional load ratio and the head flying characteristics and head adhesiveness (measured by tangential force) is as described above with reference to FIG.

[0113] Further, in the conventional textured surface shown in FIG. 26, the surface roughness is 6NmR _a, in 3-dimensional load curve, cutting area ratio of the cut surface in 5nm from the top is 0.08
%, The surface pressure of each fine protrusion due to the head load is large, and the sliding wear of the fine protrusion due to the head is remarkable along with the number of CSSs as shown by the curve D shown in FIG. Damage to the CSS
The head tangential force increased with the number of times, resulting in head crash.

Further, in the textured surface according to the present invention shown in FIG. 25, the surface roughness is 6 nmR _a , and the cut area ratio of the cut surfaces at the top 5 nm in the three-dimensional load curve.
It was 0.1-10%. In this case, as shown by the curve C in FIG. 19, the head tangential force hardly increases even if the number of CSSs increases significantly to 30,000, and very stable and highly reliable CSS characteristics are obtained. It was In this case, on the surface of the disk that slid on the head slider, there was almost no change from the initial state, and almost no damage to the lubricant or the carbon protective film was observed.

[0115] The surface roughness is 6NmR _a, the contact area of the three-dimensional load curve, when the cutting area ratio of the cut surface in 5nm from the top of the surface is 15%, the magnetic head and the disk surface Since the head adhesion force at the start of CSS is large, the gimbal that supports the head is damaged when the disk is driven to rotate, and the motor for rotating the board is overloaded, causing an accident that the board cannot rotate.

In the above embodiment, the method of forming the fine grooves and the fine protrusions using the polishing tape was described, and the advantages of various characteristics of the thin film magnetic disk using this base substrate were shown.
The same effect can be obtained not only by the polishing tape but also by a cutting method, a grinding method, a surface processing method such as lapping and polishing, a surface treatment method such as etching and sandblasting, and a pattern forming method of a dry process. Further, even when the above processing methods are combined, the same effect can be obtained.

As one embodiment of the present invention, the width of the polishing tape is narrower than the width of the processed surface of the substrate, and the contact roller for pressing the polishing tape is reciprocated in the radial direction of the substrate. The substrate surface was processed while rocking, but the width of the polishing tape was made closer to the width of the surface to be processed of the substrate, or a polishing tape with a width larger than the width of the surface to be processed was used and shaken in the radial direction of the substrate. Even if the substrate is processed without moving or swinging, the same effect can be obtained.

Further, the above texture processing is performed by Ni-P.
The same effect can be obtained by applying to an Al substrate, a non-magnetic metal underlayer, or a protective film surface in addition to the plated undersubstrate.

(5) Advantages of the Embodiment: As described in detail above, according to this embodiment, it is possible to form a highly precise fine groove having extremely small fine protrusions on the Ni-P plated base substrate. The processing method and the apparatus used directly for implementing this method have made it possible to obtain a magnetic disk having excellent CSS characteristics even when the head flying height is as small as 0.1 μm.

That is, on the surface of the magnetic disk substrate, the height
nm to several tens of nanometers of fine protrusions, surface roughness of several nanometers to several tens of nm _Ra ,
And on the surface where the symmetry R _{sk of the} cross-section curve is −0.7 or less, or on the three-dimensional load curve, from the top of the fine protrusion to C
Since it can be formed on a cut surface at a depth equivalent to the amount of top deformation received by the head load during SS, practically a surface having a cut area ratio of 0.1 to 10% of the cut surface at 5 to 10 nm from the top. In the CSS characteristic in which the magnetic head repeatedly contacts the disk surface intermittently, the head load is received by the large number of fine protrusions described above, and the surface pressure at each fine protrusion is small, resulting in deformation of the fine protrusions. , Sliding wear is reduced.

Further, deterioration of the protective film and the lubricating film formed on the fine protrusions is small, and sliding debris due to CSS is
Since the fine grooves are avoided especially in the deep groove portions, the sliding resistance is remarkably improved.

Further, in this substrate processing apparatus, by using the parallel leaf spring, the strain gauge and the pressure correction piezoelectric actuator, the pressure applied to the substrate by the contact roller is very small, and it is always uniform regardless of the shape accuracy of the substrate. Therefore, stable and uniform fine grooves can be formed over the entire surface of the substrate, and the fine protrusions of the fine grooves formed on the Ni-P plated base substrate are removed in minute amounts, so that the fine protrusions can be highly accurately formed. Can be smoothed.

Further, by the substrate processing apparatus for controlling the minute pressing force, not only the fine grooves on the surface of the base substrate but also the fine projections on the surface of the completed magnetic disk, for example, the carbon protective film, can be made fine. The fine protrusions can be reliably removed by cutting and removing each amount, and the carbon protective film around the fine protrusions and the surface forming film such as the magnetic medium are not damaged. Therefore, it is possible to obtain a very smooth surface with good surface accuracy.

[0124]

As described above, according to the present invention, the CSS characteristics can be remarkably improved even if the flying height of the head is smaller than that of the prior art, and it is suitable for high density and large capacity without causing a head crash. It has become possible to realize a highly reliable magnetic disk and disk device.
Further, it is possible to realize an improved manufacturing method in which a cutting surface load ratio based on a three-dimensional load curve of a processed surface is used as an evaluation index in a processed layer, and the first and second polishing steps in the manufacturing method are highly controlled. By implementing the processing apparatus having the first and second processing heads and the cleaning means, it is possible to realize highly accurate surface processing and realize the highly reliable disk and disk apparatus.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a substrate processing apparatus of the present invention.

2A and 2B are a plan view and a partial cross-sectional plan view showing a main part centering around a head of this apparatus.

FIG. 3 is a front view showing details of the substrate cleaning means in FIG.

FIG. 4 is a side view of the substrate cleaning means.

5 is a first processing head H of the substrate processing apparatus according to FIG.
2 is an enlarged sectional curve diagram showing an example of the surface of the substrate processed in 1.

FIG. 6 is an enlarged sectional curve diagram showing an example of the surface of the substrate further processed by the second processing head H2.

FIG. 7 is a front view showing a conventional substrate processing apparatus for forming fine grooves.

FIG. 8 is a side view of this device.

FIG. 9 is a cross-sectional configuration diagram of a thin film magnetic disk using the underlying substrate of the present invention.

FIG. 10 is a cross-sectional configuration diagram of a conventional thin film magnetic disk.

FIG. 11 is an explanatory view of a sectional shape of a fine groove.

FIG. 12 is an explanatory diagram of a conventional substrate processing apparatus.

FIG. 13 is a characteristic diagram in which the relationship between the height R _{p of the} fine protrusion, the head flying characteristic, and the head tangential force is investigated.

FIG. 14 is a characteristic diagram that examines the relationship between the symmetry R _sk , the head flying characteristic, and the head tangential force.

FIG. 15 is a characteristic diagram showing a change in the cross-sectional shape of the surface, which is measured by a high-resolution SEM for a minute change in the nanometer order on the substrate surface by CSS, (a) is before CSS, (b) is FIG. 6 is a characteristic diagram showing cross-sectional shapes after CSS.

FIG. 16 is a three-dimensional load curve of the pole surface of the substrate before and after CSS.

FIG. 17 is a characteristic diagram showing a cross-sectional shape of the substrate surface of the present invention.

18 is a characteristic diagram showing a cross-sectional shape of the surface of a magnetic disk having a magnetic medium formed on the substrate of FIG.

FIG. 19 is a characteristic diagram showing the relationship between the number of CSS times and head tangential force.

FIG. 20 is a partial cross-sectional perspective view showing the outline of a magnetic disk device to which the present invention is applied.

FIG. 21 is an explanatory diagram showing a relative relationship between a magnetic disk and a magnetic head.

FIG. 22 is a perspective view of a head slider showing the shape of a magnetic head.

FIG. 23 is a diagram showing the relationship between the head and the disk surface in CSS, and is a state diagram when the disk is stopped and when it is rotated.

FIG. 24 is a principle diagram in which SEM is applied as a method for measuring a three-dimensional surface of a textured surface.

FIG. 25 is a three-dimensional view of a textured surface of a magnetic disk according to the present invention.

FIG. 26 is a diagram in which a conventional textured surface is three-dimensionally displayed.

FIG. 27 is an explanatory view showing a relationship between a cross-sectional shape of a textured surface and a three-dimensional load curve and explaining a correlation with a CSS characteristic.

FIG. 28 is an explanatory view showing the relationship between the cross-sectional shape of the textured surface and the three-dimensional load curve and explaining the correlation with the CSS characteristics.

FIG. 29 is an explanatory diagram showing fine protrusions in the cross-sectional shape of the textured surface.

FIG. 30 is a diagram for explaining the property of the surface shape of the textured surface according to the present invention using a three-dimensional load curve.

FIG. 31 is a diagram for explaining the property of the surface shape of the textured surface according to the present invention using a three-dimensional load curve.

FIG. 32 is a characteristic diagram that examines the relationship between the three-dimensional sectional load ratio, the head flying characteristic, and the head tangential force.

[Explanation of symbols]

 1 ... Rotating shaft for mounting substrate, 2 (30) ... Magnetic disk (substrate), 3 ... Motor for driving substrate, 4a, 4b ... First polishing tape, 5a, 5b ... Supply reel, 6a, 6b ... Take-up reel , 7a, 7b ... Winding motor, 8, 9 ... Contact roller, 10, 11 ... Parallel leaf spring, 12, 13 ... Strain gauge, 14 ... Pressurizing motor, 15 ... Reciprocating motor, 17 ... Control device, 18a, 18b ... Braking torque motor, 21 ... Screw, 22 ... Reciprocating carriage, 24 ... Screw, 31 ... Non-magnetic metal base film, 32 ... Magnetic medium film, 33 ... Protective film, 34 (83) ... Lubrication film, 50 … Piezoelectric force compensation piezoelectric actuator, 60… Liquid supply part, 61 (61 ′)… Rotating scrubber, 62… Second polishing tape, 63… Reciprocating carriage, 65… Liquid tank, 80… Magnetic disk (completed product), 81 ... Magnetic head, 82 ... Head slider sliding surface, 85 ... Magnetic disk device, H1 ... First processing head, H2 ... Second Engineering head, R ... reciprocating means, S ... cleaning means, W ... rocking means.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 27, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title of invention Magnetic disk

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk ,
Particularly suitable when the recording medium was thin magnetic metal layer, magnetic
About the Ki disc .

[0002]

2. Description of the Related Art In a high-density and large-capacity magnetic disk, a magnetic recording medium formed on a non-magnetic disk substrate has a magnetic metal formed on a disk substrate from a so-called coating film in which conventional magnetic powder is bonded with resin. It has moved to a so-called thin film magnetic metal layer which is directly formed as a thin film by vapor deposition, sputtering or the like.

When the magnetic disk drive is driven, a magnetic head (hereinafter simply referred to as "head") having a specific load elastically comes into contact with the surface of a magnetic disk (hereinafter simply referred to as "disk") in a stationary state. It is pressed, and at the start, as the disc rotates,
The head begins to slide on the disk surface, and the rotation speed is several tens of minutes per minute.
When a high speed rotation of 00 rotation is reached, the head floats above the disk surface by a predetermined distance due to the dynamic pressure effect of the air flow generated between the sliding surface of the head and the disk.

In the disk device, the head can be arbitrarily moved in the radial direction of the disk in this floating state, and data reading is performed at an arbitrary position on the disk surface. On the other hand, at the time of stop, the disk starts decelerating rotation, and accordingly, the head again starts to slide on the disk surface, comes into contact with it, and stops in the pressed state.
Such driving method normally contact start stop (C ontact S tart S top, short CSS) is referred to as.

That is, in this CSS drive system, the sliding surface of the head is in the state of stopping the disk surface → sliding → floating → sliding → stopping, and this cycle is repeated each time it is driven. In order to facilitate the floating property of the head, fine grooves are generally formed in the circumferential direction of rotation on the disk surface.

FIG. 10 shows the cross-sectional structure of the disk 80. Normally, this type of groove is subjected to a surface polishing treatment called texturing in advance on the surface of the disk substrate 30 before forming a magnetic film. The thin film magnetic metal layer 32 is further formed on the surface of the substrate having such an uneven surface, and a protective film 33, a lubricating film (not shown) and the like are formed on the thin film magnetic metal layer 32, so that the surface condition of the underlying substrate is improved. The copied groove will be formed on the surface of the disk.

The texture processing of the disk substrate surface is performed by C
An important polishing technology for employing the SS drive method, for example, the maximum surface roughness of the surface irregularities of the disk substrate as described in JP-A-62-219227 0.02 to 0.1 [mu] m
As a result, the thickness of the non-magnetic metal film (Cr film) can be reduced and the productivity is improved, and as a result of the CSS test, scratches are seen on the disk surface after 20,000 times. However, it is said that when the maximum surface roughness is 0.1 μm or more, a head crash is likely to occur, and when the texture processing is not performed, scratches occur when CSS exceeds 5000 times, and a head crash is said to have occurred.

[0008] One example of a conventional texturing apparatus, as described in JP-Sho 54-23294, there is a technique as shown in FIG. 12. That is, on both sides of the rotating disk substrate 30, the polishing tapes 4 running vertically as the reel 6 rotates are sandwiched between the contact rollers 8 and pressed in the directions of the arrows so as to slide back and forth in the radial direction of the disk substrate. A device for processing both surfaces of a disk substrate at the same time is known.

7 and 8 show the positional relationship between the substrate 30 and the polishing tape 4 running thereon, FIG. 7 being a front view and FIG. 8 being a side view thereof. It is shown in. According to this type of texturing, a fine groove 37 having no polishing unevenness can be formed by the polishing tape as shown in FIG. 11, but with this formation, an unstable swelling is formed on the shoulder portion of the groove. There is a problem that the portion 36 is formed and the raised portion 36 remains on the surface as a fine protrusion.

Therefore, as shown in, for example, Japanese Unexamined Patent Publication No. 62-248133, ordinary texturing is performed in the first polishing step, and then the second polishing step is performed using abrasive grains smaller than those in the first polishing step. It has been proposed to remove only the protrusions formed on the substrate surface in the first polishing step without removing fine grooves formed on the disk substrate surface by polishing with.

[0011]

As described above, with respect to the fine grooves formed in the disk substrate by the conventional texturing, the maximum surface roughness is regulated and the protrusion on the substrate in consideration of the head floating property is taken into consideration. Regulations are shown, but CS
The optimum surface properties of the textured surface for S characteristics and head adhesion characteristics are still unknown, and problems such as head crash have not been solved yet.

In particular, the recent progress in high density and large capacity of magnetic disks has been remarkable, and accompanying this, the flying height of the head on the disk surface due to CSS has been reduced, while the head has moved to the disk surface due to, for example, disk rotation. A narrower condition is required such that the gap between the disk surface and the head sliding surface in the floating state (so-called flying amount) is 0.2 μm or less.

Therefore, in order to realize this strict condition by the texturing, it is natural that the height of the protrusion raised on the shoulder portion is set to be equal to or less than the floating amount by forming the groove, and the head is lifted when the head is floated. Must be prevented from coming into contact with the protrusion, and extremely strict disk surface properties are required. If the contact between the protrusion and the head sliding surface is simply avoided, it is sufficient to change the shape of the head sliding surface, the head load, the number of rotations of the disk, etc. to secure a sufficient flying height of the head.

However, as described above, the flying height must be reduced as the recording density of the disk device increases (ideally, the head and the magnetic film should be in intimate contact with each other as much as possible). In order to reduce the amount of deformation and the amount of friction and wear of this protrusion, the heights of the protrusions are made uniform, the contact area with the head sliding surface is increased, and sliding debris is also avoided. It is necessary to have deep grooves.

Therefore, as described above, in order to make the heights of the protrusions formed by the groove formation uniform, the polishing process of the disk substrate surface is divided into the first and second two-step processes, and the second process is used. Although it is attempting to polish and align the protrusions with each other, it is unclear about the CSS texture when the flying height of the head is small and the surface texture of the optimum texturing for the head adhesive property, and the problems such as head crash still remain. Not resolved. That is, if the heights of the protrusions are made uniform by sufficient polishing, the sliding area of the head with respect to the disk surface (strictly speaking, the polishing surface that contacts the head sliding surface of the protrusion) increases, The flying property of the head decreases, and the lubricant (generally a lubricating film is formed) on the disk surface and moisture in the atmosphere adhere to the sliding surface of the head, which accumulates due to surface tension, and finally the head. The sliding surface of the disk is attracted to the disk surface, which causes a new problem that the disk cannot rotate and the head part is damaged.

Therefore, an object of the present invention is to solve these problems of the prior art, and to provide an improved magnetic disk which has excellent CSS characteristics even when the head flying height is smaller than that of the prior art, and in which head crush does not easily occur. To do .

[0017]

The above object of the present invention is to:
(1) Magnetic recording of information formed on thin film on non-magnetic substrate
A magnetic disk having a film, a protective film, and a lubricating film.
The surface shape of the magnetic disk is almost flat.
The surface shape of the magnetic disk has a smooth protrusion.
Deformation amount phase from the top of the surface to the three-dimensional curve
The load ratio on the cut surface of the depth is 0.1-10%
It is achieved by the magnetic disk characterized by
It

Preferably, (2) at least a non-magnetic substrate having a finely textured surface processing layer on its main surface, and at least a thin-film magnetic layer sequentially formed on the non-magnetic substrate following the irregular surface. In a magnetic disk having a metal layer and a protective layer thereof, the surface shape of the convex portion in the surface processing layer of the non-magnetic metal substrate has a convex portion whose surface is substantially smoothed, In the three-dimensional load curve showing the surface shape, 5 to 5 from the top of the convex surface
The load ratio in a cross section of the depth of 10nm and 0.1% to 10%
And more preferably (3) a magnetic disk in which the three-dimensional load curve of the surface shape of the non-magnetic metal surface-treated layer has a flat shape on the pole surface, and more preferably (3) 4) As the surface shape of the surface processed layer of the non-magnetic metal substrate, a concave fine deep groove having a depth of at least 100 nm within the width of the sliding surface of the head slider and R _sk ≦ −0.7 indicating the _symmetry of the cross-section curve. This is accomplished by a magnetic disk comprising.

Here, the results of the study by the present inventors leading to the present invention will be described in detail below. The CSS causes the outermost surface of the disk to change on the order of nanometers (nm) by sliding the head slider on which the magnetic head is mounted. This change smoothes the disk surface and increases the horizontal resistance force exerted on the head. Head crash occurs,
Alternatively, we experienced a problem in which an accident such as disk incapability occurred when the head was stuck when the CSS stopped. Therefore, with respect to the processed surface of the disk substrate by the texture processing, the CSS characteristics of the magnetic disk and the sliding resistance characteristics such as head crash can be explained simply by the regulation of the maximum surface roughness and the height of the convex portion. I knew I couldn't.

It is more important than the maximum surface roughness to have an overall property including the shape of the convex portion from the average surface and the shape of the groove having the surface unevenness, and the property of the three-dimensional load curve as described later. No consideration has been made in the past,
I noticed that the most important presentation was not made regarding the surface ruggedness of the underlying substrate for which head crash and CSS characteristics should be improved.

The magnetic disk device 85 is generally composed of a plurality of magnetic disks, as shown in the partial sectional perspective view of FIG.
80 are mounted and fixed on the same rotary shaft at predetermined intervals, and magnetic heads 81 for recording and reading information are installed on both sides of each disk. 21 is an explanatory view schematically showing the relationship between the disk 80 and the head 81 (also referred to as a head slider) in the disk device shown in FIG.
The head 81 is fixed to the tip of the arm 84, and when the disk is stationary or in the initial state of rotation, the elastic force of the arm 84 is pressed onto the disk surface to bring it into contact and slide, but the disk rotates at high speed. In this state, the head 81 is in a state of floating with a submicron flying height due to the effect of the air flow with the disk 80.

FIG. 23 specifically shows these states.
23A shows a contact state when the disc is stopped and sliding, and FIG. 23B shows a floating state when the disc rotates at a high speed. The shape of the head 81 has sliders 82 that slide on the disk surface on both sides of the head, as shown in FIG.

As an example of the dimensions of the head slider surface 82, the width w is 0.4 mm and the length l is 4 mm, and the length l (el) direction of this head slider is the same as the circumferential direction of the disk. Is installed as. Therefore, the uneven shape of the disk surface is problematic at least for the head slider width w, that is, a dimension of 0.4 mm or a dimension of 0.4 mm or more.

A method of measuring the cross-sectional shape of the textured substrate surface will be described. This cross-sectional shape is a Talystep surface roughness meter (Rank Taylor Hobson)
Using a stylus whose stylus shape is 0.1 μm × 2.5 μm, the head slider width w
(Eg 0.4mm) or head slider width 0.4
It is a curve measured with a length of mm or more. The output signal from the Taristep is A / D converted, and by computer processing,
The sampling interval was 40 nm.

As shown in FIG. 29, the fine protrusion means the above-mentioned cross section measured in the radial direction of the disk substrate with respect to the textured surface formed in a substantially circumferential direction or in a spiral shape. Regarding the curve, the convex direction from the center line C of the cross-sectional curve, that is, individual peaks having a minute height (referred to as convex portions in the present invention) are shown. Further, the height R _p of the fine projection represents the distance between the highest peak of the individual peaks in the unit length L measured in the radial direction and the center line.

As the surface texture of the textured surface, the symmetry of the texture section curve is represented by R _sk obtained by the following equation according to a well-known display method. If the sectional curve is a function Y (i), it can be expressed by the following general formula.

[0027]

[Equation 1]

That is, when R _{sk indicating} symmetry is negative, the groove component of the cross-sectional curve is large, and when it is positive, the protrusion component is large. When R _sk = 0, it means that the component of the protrusion and the component of the groove are equal, and the sectional curve is symmetrical with respect to the center line C.

Here, a method for three-dimensionally measuring the unevenness of the textured surface will be described with reference to FIG. FIG. 30A shows an STM (scanning tunnel) described later.
3G shows the result of three-dimensional surface measurement G of the textured surface by a ling Microscope. From this, the three-dimensional surface is cut at a plane H parallel to the average plane (plane from the outermost surface to a depth Δhi) at equal intervals. FIG. 30 (b) is a graph of the area ratio (ΔLi) obtained by dividing these cut areas by the total area of the reference plane E deeper than the uneven processing layer for each cut surface. That is, FIG. 30 (b)
Is a three-dimensional load curve.

This three-dimensional load curve is generally an Abbott load curve, ABBOTT-FIRESTONE (OR BEA, for a two-dimensional cross-section curve, as shown in FIG.
RING RATIO) It has the same contents as CURVE, but is developed in three dimensions. This Abbott load curve is used to evaluate the sliding characteristics of the bearing and the like. The present inventors have observed the contact phenomenon between the head and the disk in detail with respect to the state of the head sliding surface, the state of the disk surface, and the motion state of the head and the disk in CSS, and as a result of the measurement, As a method to evaluate the disk surface with high accuracy for sliding characteristics such as STM
It has been found that the three-dimensional load curve according to Eq.

That is, this load curve is shown in FIG.
As shown in (a) and (b), the surface shape is cut at regular intervals from the top of the three-dimensional shape with respect to the reference area E of the three-dimensional shape G on the surface, and the three-dimensional shape by the cut surface H is obtained. A curve obtained by dividing the sum of the respective cut areas by the reference area E in each cut surface is shown. At the top of the surface shape, the cut area by the cut surface is small, and the cut area ratio is small. That is, if there is a sliding body on this surface, since the sliding body is supported only by the top portion of the surface shape at the initial stage of sliding, the pressure receiving area is small and the surface pressure is large, so the sliding portion causes the top portion to frictionally slide. , Wear and deformation easily occur.

Therefore, on the surface having a large cutting area ratio at the top of the surface shape, that is, in the three-dimensional load curve, in the range where the cutting area ratio is small, the surface showing the surface shape with a small load curve gradient has a pressure receiving area Large in the initial state,
Since the surface pressure of each fine protrusion that supports the sliding body is reduced, the sliding resistance is improved. As described above, the three-dimensional load curve is one of the evaluation methods that express the load capability with respect to the surface texture of the surface to be slid on the sliding body.

As a method of measuring the three-dimensional surface of the textured surface, SEM (Scanning Electron Microscop) is used.
FIG. 24 shows the measurement principle applying e). That is , to explain according to the figure, two secondary electron detectors A,
With B, the signal intensities a and b at the incident angle θ (inclination of the sample) of the electron probe are detected, and the incident angle 0
As the signal intensities an and bn at the time of (irradiation on a plane), the following general formula

[0034]

## EQU2 ## θ is calculated from tan θ = k {(a ² −b ² ) / (an + bn) ² }, where k is a constant. By integrating the inclination of the sample thus obtained, the surface shape in the X-axis direction can be measured. For example, an electron beam surface morphology analyzer manufactured by Elionix Inc. can be cited as this type of measuring device. Furthermore, if scanning in the Y direction, the shape of the three-dimensional surface can be measured.

The present invention has been made on the basis of the above findings. The details of the study will be described in more detail below. As is well known, the substrate of the magnetic disk is a non-magnetic substrate such as an aluminum alloy, anodized aluminum, or an aluminum alloy coated with Ni-P plating,
Further , it is necessary to form a large number of uniform fine grooves and fine protrusions on the surface of the substrate, which is made of a substrate such as glass or plastic and is one factor for improving the characteristics.

These fine grooves and fine protrusions are formed on the surface of the substrate with a cutting and polishing tool such as a diamond bite or fine abrasive grains so that the shoulders of the groove portions are shown in FIG. The raised portion 36 is formed. The rising height of these fine protrusions is set by the depth and size of the groove 37, and the number of fine grooves is set by the processing conditions such as the density of fine abrasive grains and tool feed.

[0037] Here, essential gist as the surface shape of the magnetic disk, without causing head crashes, and electrical properties, is to satisfy the properties of the CSS characteristics, magnetic disks, such as head adhesion characteristics. In order to achieve a high density of the magnetic disk, the head flying gap is narrowed, so that the disk surface is required to have an ultra-smooth surface in order to avoid collision between the head and the disk.

On the other hand, since it is necessary to shorten the head access time, the head 81 and the disk 80 are in contact with each other at the time of stop as shown in FIG. 23, and float as the disk rotates, so-called contact start stop (hereinafter referred to as C).
Abbreviated as SS). Therefore, when the surface of the disk 80 is a smooth surface, that is, the surface roughness is very small, the head and the disk are adhered to each other by the lubricant 83 on the disk surface or moisture in the atmosphere when the disk is stopped, and the head is supported when the disk is rotated. There was a problem that the gimbal and arm were damaged and could not be rotated.

The results of experiments conducted by the present inventors are shown in FIGS. 13, 14 and 32. The height of the fine projections, the symmetry of the texture section curve, and the three-dimensional section load ratio, the head flying characteristics, and the head adhesiveness, which are formed by the texture processing (details will be described later) formed on the base substrate using the polishing tape. Shows the relationship.

That is, FIG. 13 shows the relationship between the protrusion height, the head flying height H _t0 as the flying characteristic, and the head tangential force F _t as an index of the head adhesive force, and FIG. 14 shows the symmetry R _sk.
FIG. 32 shows the relationship between the three-dimensional sectional load ratio (at the tangential sectional depth of 5 nm from the top) and the flying height H _t0 and the head tangential force F _t , respectively. The method is as follows.

(1) Measurement of head flying height H _t0 : In principle, the head has the same configuration as the disk device 85 of FIG. 20, an AE sensor is mounted on the head 81, and when the disk 80 starts rotating. , The head 81 starts to float, and the disk rotation speed at which the output signal from the AE sensor detecting the contact state with the disk surface sharply decreases is measured. On the other hand, the flying characteristics of the head depending on the number of revolutions of the disk are previously checked, and the flying start height H _t0 of the head is measured.

(2) Measurement of head tangential force F _t : The sliding resistance force of the head during one rotation (1 _r / min) of the disk is measured by a strain gauge installed on the support arm 84 of the head 81.

From this result, there is an effective range of surface properties suitable for simultaneously satisfying both the head flying characteristic and the head adhesiveness such that the flying height H _t0 is small and the tangential force F _t is small. Recognize. That is, as shown in FIG. 13, the small protrusions R _p are preferably in the range of several nm to several tens of nm, more preferably in the region indicated by the arrow, and the symmetry R _sk is shown in FIG. A negative region, preferably a region of R _sk ≦ −0.7 indicated by an arrow is desirable.

Regarding the relationship with the three-dimensional cross-section load ratio, as shown in FIG. 32, the lower limit of the effective load ratio is from the flying characteristics, and the upper limit is the head adhesive force (indicated by the head tangential force F _t ). It was regulated by 0.1 to 10%, more preferably 0.24 to 8.5%.

[0045] Furthermore, the relationship between surface shape and CSS characteristics described above will be described with reference to FIGS. 27 to 28. Figure 2
7 (a) shows the cross-sectional shape of the surface of the underlying substrate that is textured using fine abrasive grains, and fine protrusions are present with variations.

As shown in FIG. 27 (b), the three-dimensional load curve of the textured surface shows that the gradient of the load curve is in the range where the cutting area ratio is small, that is, in the range of part A in FIG. 27 (b). large. When the magnetic head repeats CSS on the surface as shown in FIG. 27 (a), the fine protrusions are less in contact with the head slider surface, so that the surface pressure W / S (W: head load, S: head slider). The actual contact area between the disk and the disk surface) becomes large, resulting in severe wear or deformation, and the number of thicknesses formed on the underlying substrate on which minute protrusions are formed.
The lubrication film with a thickness of 10 nm and the protective film with a thickness of several 10 nm are greatly damaged.

On the other hand, the wear or deformation of the fine protrusion due to CSS is σ <W /, where σ is the yield strength of the fine protrusion.
In the state of S, it occurs violently and decreases in the state of σ ≧ W / S. Therefore, the wear and deformation of the fine protrusions caused by CSS increases the true contact area, resulting in the true contact area S satisfying the above σ ≧ W / S. If it is formed without being damaged, wear and deformation of the fine protrusions are almost eliminated, and a stable surface is obtained.

Therefore, the underlying substrate having the cross-sectional shape shown in FIG. 27A is further surface-processed to form a model trapezoidal shape in which the fine protrusions as shown in FIG. 28A are smoothed. . If the true contact area between the head slider and the disk surface is increased to make the surface shape of the true contact area such that σ ≧ W / S in the initial state, the surface pressure of the fine projection becomes small. Almost no wear or deformation is obtained, and a stable and highly reliable surface can be obtained as a magnetic disk. The surface shape 3 shown in FIG.
The dimensional load curve is as shown in FIG.
It can be seen that the slope of the load curve on the pole surface is very small, as shown in part A of (b).

In an experiment conducted by the present inventors, a conventional textured surface having a three-dimensional surface shape as shown in FIG. 27A has a surface corresponding to the head slider surface (for example, 0.4 mm × 0.4 mm). 3D load curve on the surface) is 5 nm to 10 nm from the top of the surface shape, that is, the cut area ratio at the cut surface depth of 5 nm to 10 nm is 0.1% or less, and such a base substrate was used. In the magnetic disk, head crash occurred when the CSS number was 2000 times or less.

On the other hand, the texture-processed material of the present invention, as shown in FIG.
The surface as shown in 8 (a), that is, the depth of the cut surface is 5 nm
In a magnetic disk using a base substrate having a three-dimensional load curve surface with a cutting area ratio of 0.1 to 10% at ~ 10 nm, the protective film and lubricating film maintain their respective functions when the CSS count is 20000 or more. However, the surface condition was stable.

Further, detailed changes of the magnetic disk surface due to CSS were examined. In the experiments conducted by the present inventors, the contact start / stop CSS test was performed on the textured substrate.
From the surface shape measured from the SEM observation of the disk surface subjected to the SS test, and from the three-dimensional load curve of the disk pole surface shown in FIG. 16, the top of the fine protrusion in the initial state was smoothed by repeated sliding of the magnetic head. It has been found that the area of the fine protrusions in contact with the head and the disk at this time increases.

That is, FIG. 15 (a) shows the surface shape in the initial state, and FIG. 15 (b) shows the state after the surface has been deformed by repeated sliding by CSS. Further, the load curve B in FIG.
The characteristics of (a) in the initial state, and the load curve A
Shows the characteristics after repeated sliding in FIG. 15 (b).

Here, for example, the change in the surface when the number of CSS times is 20,000 is 5 to 5 times from the top in the initial state due to the contact with the slider surface of the magnetic head as shown in part A of FIG. If the fine protrusion changes by 10 nm and the fine protrusion changes from the top of the initial state by 5 to 10 nm from the three-dimensional load curve of the disk surface at this time shown in FIG. 16, the cutting area contact with the magnetic head becomes 0.1. It was about a few percent to a few percent.

That is, if the height of the fine protrusions is several tens of nm or more, the flying characteristics of the magnetic head are deteriorated, causing a head crash, and even if the fine protrusions are several nm or less, the cutting area is small. When the ratio is small, the substrate surface that supports the head load when the head is slid in the CSS test, that is, the load area of the fine protrusions is small, the surface is smoothed immediately with CSS times, and the head tangential force increases, causing a head crash. Is likely to occur.

Further, when the load area of the fine protrusions is small, the surface pressure of the fine protrusions which receives the head load becomes large, so that the fine protrusions are easily reduced or worn, and the lubrication of several nm formed on the substrate surface is performed. If the agent layer or the protective film layer is easily damaged, and if the cutting area ratio is 10% or more and the load area is large, the change of the fine protrusions on the substrate by the magnetic head is small, but the contact area becomes large. Head adhesion is likely to occur due to the influence of the lubricant and moisture in the atmosphere, and the sliding resistance of the magnetic head during CSS increases, causing problems such as gimbal and arm destruction of the magnetic head, and difficulty in rotating the disk.

[0056] Thus, textured substrate surface shape of the floating characteristic and head load of the head, considering the surface changes due to frictional wear by the head slide, from the above results, the height of the fine projections is several nm ~ Several tens of nm, surface roughness is several
nmR _a to several tens of nmR _a , and the symmetry R _{sk of the} cross section curve is negative,
The surface is preferably -0.7 or less, more preferably -1 or less, or, in a three-dimensional load curve, a cut surface at a depth corresponding to the amount of top deformation received by the head load during CSS from the top of the fine protrusion, practical. 5-10 nm from the top
A surface having a cutting area ratio of 0.1 to 10% is desirable.

From this point of view, the optimum surface for the magnetic disk substrate is, as shown in FIG. 6, a pseudo circumferential fine groove is formed on the substrate surface, that is, a cross-section of the textured substrate surface. The shape is such that the height of the fine protrusion is several nm to several tens.
nm and uniformly smoothed, and the surface roughness is several nm _Ra to several tens n.
mR _a (preferably 5 nm to 9 nm _Ra ), and the symmetry of the cross-section curve R _sk ≦ -1, the cutting area ratio at the top 5 to 10 nm is 0.1.
~ 10%.

Further, in order to maintain the smooth head sliding on the disk, when the deep groove V as shown in FIG. 6 is used as the unit width of the slider width in the uneven processing layer on the disk surface, It is important that the groove V always exists within the width, and it has been found that it is effective if the depth of the deep groove V is at least 100 nm.

[0059]

[Function] The height of the fine protrusion formed on the magnetic disk substrate is several nm to several tens nm, and the surface roughness is several nm _Ra to several tens nm.
On the surface of _Ra , and the symmetry _{Rsk of the} cross-section curve is -0.7 or less, preferably -1 or less, especially on a three-dimensional load curve, the amount of top deformation corresponding to the top load received by the head load during CSS from the top of the fine protrusions. cutting plane at a depth, for practical purposes, the disk surface, the slider surface of the CSS during head of the magnetic head having a cutting area ratio of the cut surface in 5~10nm from the top surface shape is 0.1% to 10% In contact with and receive a preferred head load.

Further, the surface irregularities of the disk surface retain the lubricating film applied on the surface of the magnetic disk and at the same time prevent the adhesion with the magnetic head, and the sliding debris generated by the sliding of the head in the deep groove of the disk surface. There is an action to avoid. Further, since a large number of fine protrusions are in contact with the head slider surface, and the cutting area ratio is 0.1 to 10% at 5 to 10 nm which is practically preferable from the top where surface change due to head sliding occurs,
Surface pressure of individual fine projections becomes small, the change in the fine projections by repeating the CSS, i.e. deformed or depletion less, to maintain the surface shape of the initial state.

Further, the height of the fine protrusions is several nm to several tens nm, which is very small with respect to the flying gap of the magnetic head (the gap between the magnetic head and the magnetic disk surface in the steady state) of 150 to 250 nm. Even if the assembling accuracy and rotation accuracy of the magnetic disk and the floating fluctuation of the magnetic head are taken into consideration, the magnetic head floats with a sufficient margin, and head crash due to collision of the magnetic head does not occur.

Therefore, the protective film and the lubricating film having a thickness of several nm formed on the surface of the magnetic disk are hardly worn or damaged, the head is not adhered, and the tangential force of the head is not increased by repeating CSS. It is possible to obtain a magnetic disk having high reliability with respect to head flying characteristics and sliding resistance characteristics.

[0063]

[Example] <Example 1> As a disk substrate, an inner diameter of 40 mm, an outer diameter of 130 m
Aluminum alloy plate of m is used.
After P-plating and smooth polishing to _a surface roughness of 2 to 3 nm _Ra or less, _a groove shape is formed by a polishing tape as shown in FIG. Number 10
in nm and uniformity, surface roughness 5～8NmR _a, and symmetry R _sk sectional curves were polished such that Do and -1-2. The cross-sectional shape in FIG. 17 was measured by using a surface roughness meter Taristep and measuring with a stylus shape of 0.1 × 2.5 μm in a direction perpendicular to the groove. A specific method of manufacturing these disk substrates will be described later in detail.

As shown in the cross-sectional structure of the magnetic disk in FIG. 9, the thickness of the disk substrate thus obtained is about
300 nm of Cr-based non-magnetic metal base film 31 and 60 nm of Co
-Ni-based magnetic thin film media 32 are sequentially formed by sputtering, respectively, and a carbon protective film 33 having a thickness of about 50 nm is further formed.
Then, a lubricating film 34 was sequentially formed on it.

As shown in FIG. 18, the surface shape of the magnetic disk thus manufactured is almost the same as that of the disk substrate shown in FIG. 17, and the surface roughness is 5.5 nmR.
_a (5.3 nm _Ra on the substrate), the height R _p of the fine protrusion is 19 nm
(At the same 20 nm), and the symmetry R _sk of the cross-sectional shape was almost the same.

A plurality of this magnetic disk are incorporated in the same manner as the magnetic disk device 85 of FIG. 20, and the head floating clearance is 0.2 μm.
As a result of the flying test, the contact between the head and the disk surface was not detected, good flying characteristics were exhibited, and almost no change in the magnetic disk surface shape due to the number of CSSs was observed.

FIG. 19 is a characteristic curve diagram showing the relationship between the number of CSS times and the head tangential force (unit: Newton N) in this embodiment in comparison with the conventional comparative example. The curve C is the present example and the curve D is the comparative example. As is clear from this figure, in the case of the present example, the head tangential force hardly increases even with 30,000 CSS times, and there is also a problem of head adhesion. It did not occur, and the reliability of the magnetic disk could be greatly improved.

As a comparative example, as shown by the curve D, in the magnetic disk in which the fine groove of the sectional shape as shown in FIG. 5 is formed on the underlying substrate by the conventional technique, the head tangential force D increases with the number of CSS and the magnetic head There were problems such as damage and head crash. Further, it can be seen that the cross-sectional shape of the disk surface changes remarkably with the number of CSSs as compared with the present invention.

Here, the method for manufacturing the substrate of this embodiment will be specifically described below. A Ni-P plated film having a thickness of 10 μm was formed on both surfaces of an aluminum alloy disk substrate by an electroless plating method, and smooth-polished to a surface roughness of 0.01 μm R _max or less. Then, as a first polishing step, surface processing is performed with a polishing tape of alumina abrasive grains having a grain size of # 3000 to form fine grooves on the surface of the Ni-P plated substrate.

This surface processing method is described, for example, in Japanese Patent Laid-Open No. 54-2329.
As shown in Japanese Patent Publication No. 4, the polishing tape 4 is pressed against the both surfaces of the substrate 30 shown in FIG. 12 by the contact rollers 8 to wind the polishing tape on the reel 6 while rotating the substrate, and By reciprocally sliding on the substrate so as to slide on the entire surface of the substrate, fine grooves approximately in a circular shape or a spiral shape are formed on both surfaces of the substrate.

Next, on the surface of the substrate, several abnormal fine protrusions having a height of 100 nm or more are formed, particularly in the shoulder portion of the deep groove, which is a cause of deterioration of the head floating characteristic and further head crash accident. It becomes a factor. Therefore, in the second polishing step, a surface treatment was performed in the same manner as in the first polishing step, using a polishing tape having a smaller grain size than the polishing tape in the first polishing step. As a result of the surface processing of the second polishing step, the height of the abnormal fine protrusions is reduced, the tops of many fine protrusions are smoothed, and the fine protrusions H are smoothed as shown in FIG. Moreover, it was possible to form a surface having a cross-sectional shape in which deep grooves V were formed periodically.

During the first and second polishing steps,
A substrate surface cleaning step was provided in order to remove stains on the surface of the substrate such as processing scraps resulting from the surface processing in the first step. In the second polishing step, as a means for detecting the polishing end point, the above-mentioned three-dimensional load curve is obtained based on the principle of SEM in FIG. 24 and the load curve by STM shown in FIG. The point where the cutting area load ratio obtained by cutting at a depth of 5 to 10 nm from the topmost portion satisfies the condition of 0.1 to 10% was made the end point.

<Embodiment 2> An embodiment of a texture processing apparatus for the surface of a disk substrate suitable for manufacturing the magnetic disk of the present invention will be described below with reference to the drawings.

(1) Description of processing apparatus configuration: FIG. 1 is a front view showing an embodiment of an apparatus for texture-processing a substrate surface of the present invention, and FIG. 2 is a plan view showing a main part of this apparatus. Three
FIG. 4 is a front view showing details of the substrate cleaning means in FIG. 1, and FIG. 4 is a side view of the substrate cleaning means.

First, an outline of this substrate processing apparatus is shown in FIG.
Explaining using (a), this apparatus is a substrate support 1 capable of rotatably supporting a substrate 2 which is a workpiece, and a first polishing tape 4 on both sides of the substrate 2 at a time. Set of contact roller units C capable of being pressed by the pressing force, a tape winding motor 7 for winding the first polishing tape 4, and the contact roller unit C swinging in the radial direction of the substrate 2. A first processing head disposed on one side of the substrate support, which has a swinging means W capable of moving and a reciprocating means R capable of reciprocating the contact roller unit C in the radial direction of the substrate 2. H1 and the first processing head H1 have the same configuration, and are arranged on the side opposite to the first processing head H1 with respect to the substrate support, and instead of the first polishing tape, they are more abrasive. 2nd small particle size A pair of machining heads of a second machining head H2 Metropolitan wearing the tape, the substrate 2
Is disposed between both the processing heads and the substrate drive motor 3 relating to the substrate rotating means that can rotate the relative speed of the first and second polishing tapes at a predetermined value. This is a substrate processing apparatus including a substrate cleaning means S capable of cleaning, both the processing heads H1 and H2, a substrate drive motor 3, and a controller 17 capable of controlling the substrate cleaning means S. It should be noted that FIG. 1B is an enlarged view of a main part mainly including the first head H1 of FIG.

Further, the above processing head H1 will be described in detail with reference to FIG. 2A which is an enlarged plan view of a main part thereof and a plan view (including a partial cross section) of the main part. The processing head H1 moves a pair of parallel leaf springs 10 and 11 supported by the reciprocating means R so as to be movable in the axial direction of the substrate 2, and the parallel leaf springs 10 and 11 to move the polishing tape 4 Pressurizing and moving means 23 that eliminates the influence of back tension due to winding and enables setting of a predetermined minute pressing force, and corrects minute fluctuations of the pressing force due to the influence of the substrate shape accuracy during substrate processing with good responsiveness. Attached to the parallel leaf springs 10 and 11 and the pressing force correction means 50 (for example, a piezoelectric actuator or the like), which are installed on both sides of the substrate 2 and whose central axes are attached in the radial direction of the substrate 2. Contact rollers 8 and 9, a polishing tape driving device 7 attached to the reciprocating means R and sliding the polishing tape 4 between the substrate and the contact roller, and the parallel leaf spring 10.
A stress measuring means (12, 13) attached to the (11) and a control device (17) for controlling the pressure moving means (23) and the pressing force correcting means (50) according to the output of the stress measuring means are provided.

Therefore, in this substrate processing apparatus, the fluctuation of the back tension due to the winding of the polishing tape, which is a slight fluctuation factor of the applied pressure, that is, the diameter of the polishing tape wound around the supply and winding reels 5 and 6 is reduced. The pressure changes as the tape tension changes as the tape is processed. This variation is always measured by the stress measuring means 12, and if the parallel leaf springs 10 and 11 are adjusted by the pressure moving means 23 according to the variation, the contact roller is irrespective of the variation in the tension of the polishing tape. The pressure applied to the substrate 2 by 8 and 9 can be made constant. Further, in order to improve the responsiveness of the correction of the pressing force with respect to the waviness in the circumferential direction of the substrate during the processing and the fluctuation of the pressing force due to the warp in the radial direction of the substrate, the pressing force correction means 50 such as a piezoelectric actuator is used. A minute pressing force can be corrected with good response. With the above functions, it becomes possible to form fine grooves with high precision.

The first processing head H1 is disposed on one side of the substrate support 1 (right side in FIG. 1A),
It is used to form fine grooves (for example, fine grooves having a depth of about 0.1 μm) on both surfaces of the substrate 2 in the first polishing process. This processing head H1 is a set of two contact roller units C arranged so as to come to both sides of the substrate 2.
A tape winding motor 7a for winding the first polishing tape 4 mounted on each of the above from the lower side to the upper side, and a swinging means W capable of swinging the contact roller unit C in the radial direction, and reciprocating in the radial direction. And a reciprocating means R that can be moved.

Each of the contact roller units C applies a predetermined pressure to the contact roller 8 via the parallel roller spring 10 and the contact roller 8 used to press the first polishing tape 4 against the substrate 2. And the parallel plate spring.
A strain gauge 12 for detecting a pressing force is adhered to the pressing member 10. The pressing motor 14 is loaded with the pressing force by displacing the parallel leaf spring 10 in a direction perpendicular to the surface of the substrate 2. Can press force compensation piezoelectric actuator 50
Is capable of correcting minute fluctuations in pressing force during processing with good responsiveness.

The swinging means W comprises a swinging motor 16 and a crank 55 that connects the shaft of the swinging motor 16 and the first machining head H1. Further, the reciprocating means R controls the rotation of the reciprocating motor 15 to the first machining head H.
The screw is transmitted to 1 to reciprocate the machining head.

As described above, the second processing head H2 has the same structure as the first processing head except that the second polishing tape is mounted instead of the first polishing tape, and the substrate supporting unit H2 supports the substrate. It is disposed on the other side of the tool (left side in FIG. 1A) and is used for the second polishing step for removing the protrusions of the fine grooves formed on both sides of the substrate by the first processing head. It is something.

Further, the structure of the processing head will be described in detail with reference to FIG.

The reference numeral 1 designates a horizontally mounted rotary shaft for mounting a substrate,
2 is a substrate which is a workpiece, 3 is a drive motor for rotating a rotary shaft, 21 is a screw rotatably supported, and 15 is a screw
A reciprocating motor for rotating 21 and a reciprocating pedestal 22 movably supported in the radial direction of the substrate, that is, in the direction of arrow A. The reciprocating pedestal 22 is provided with a female screw, and the female screw is It is screwed into the screw 21, and the screw 21 and the motor 15 constitute a reciprocating means R. 23 is the reciprocating carriage 22 and arrow A
16 is a reciprocating carriage 22 that is supported so that it can move in any direction.
The vibrating device fixed to the moving body 23 by the vibrating device 16.
Is vibrated with a small amplitude.

More specifically, referring to FIG. 2, 24 is a screw rotatably supported by the moving body 23, 14 is a pressurizing motor for rotating the screw 24, and 10 and 11 are the moving body 23 and the substrate 2. A pair of parallel leaf springs movably supported in the axial direction of arrow B, that is, the direction of arrow B, is provided with a female screw on the support base 51 of the parallel leaf springs 10 and 11, and the female screw is screwed into the screw 24. In addition, the screw 24 and the motor 14 constitute a pressure moving means.

Further, when the undulation in the circumferential direction or the warp in the radial direction of the substrate is bad, the applied pressure fluctuates during processing.
For this reason, the parallel leaf springs 10 and 11 are installed on the support base 51 provided with the pressure correction piezoelectric actuator 50, the support base 51 is provided with a female screw, and this female screw is screwed into the screw 24 as described above.

Contact rollers 8 and 9 are rotatably attached to the parallel leaf springs 10 and 11. The contact rollers 8 and 9 are provided on both sides of the substrate 2 and the central axes thereof are attached in the radial direction of the substrate. ing.

18a and 18b are braking torque motors attached to the moving body 23, 5a and 5b are supply reels attached to the output shafts of the motors 18a and 18b, and 7a and 7b are windings attached to the moving body 23. Motors, 6a and 6b are motors 7a and 7b
Of the take-up reel mounted on the output shaft, 4a, 4b in the abrasive tape adhered held by a binder of fine abrasive grains, such as diamond abrasive grains or alumina abrasive grains to a substrate such as a polyester film such as a resin, polished Both ends of the tapes 4a and 4b are fixed to the supply reels 5a and 5b and the take-up reels 6a and 6b, and the motors 18a and 18b, the supply reels 5a and 5b,
The motors 7a and 7b and the take-up reels 6a and 6b constitute a polishing tape driving device, and the polishing tapes 4a and 4b pass between the substrate and the contact roller.

Reference numerals 12 and 13 are strain gauges attached to the parallel leaf springs 10 and 11, 17 is a control device for controlling the motors 3, 14, 15 and the like. The control device 17 responds to the outputs of the strain gauges 12 and 13. The parallel leaf springs 10 and 11 are moved by controlling the motor 14 and the pressurizing force correction piezoelectric actuator.

Next, the substrate cleaning means S in FIG. 1A will be specifically described below with reference to FIGS. 3 and 4. FIG. 3 is a front view for explaining the main part, and FIG. 4 is a side view thereof. The substrate cleaning means includes a rotary scrubber (made of brush or sponge) 61 that simultaneously cleans both sides of the substrate, and a scrubber drive motor M that rotates the rotary scrubber 61.
, An air cylinder (not shown) capable of reciprocating the rotary scrubber between a broken line position 61 'and a solid line position, and a liquid tank 65. Reference numeral 60 is a supply unit that supplies the processing liquid and the cleaning liquid.

(2) Description of the operation of the above apparatus: First, referring to FIG.
The substrate 2 is attached to the substrate support 1 of the processing apparatus of (a). Processing conditions such as a pressing force, a relative speed, a vibration amplitude, and the number of reciprocations are set in the control device 17 in order to carry out the first polishing process.

Here, when the substrate processing apparatus is turned on, the substrate is rotated by the motor 3, and at the same time, the first processing head H1 is oscillated by the oscillating motor 16 at the set oscillation amplitude, and the polishing tape driving device 7 When the polishing tapes 4a, 4b are wound with a constant force with the pressure applied to the substrate to be the set first pressure, and the reciprocating means R reciprocates the reciprocating table 22, the polishing tape Fine grooves are formed on the surface of the substrate 2 by 4a and 4b. During this period, the rotation speed of the substrate 2 is controlled by the substrate drive motor 3 to
The relative speed with respect to the polishing tape 4 is adjusted to be the set first relative speed. While the processing is proceeding in this way, the processing liquid is continuously supplied from the supply unit 60 to the substrate.

Even if the tension of the polishing tapes 4a, 4b fluctuates and the parallel leaf springs 10, 11 are deformed, the control device
Since the motor 17 controls the motor 14 according to the outputs of the strain gauges 12 and 13, that is, according to the deformation amount of the parallel leaf springs 10 and 11, the parallel leaf springs 10 and 11 have the polishing tape 4a,
Contact roller 8, regardless of the fluctuation of tension in 4b,
Since the pressing force of the substrate 9 on the substrate 2 can be made constant, a minute pressing force can be always maintained, so that small and uniform fine grooves can be formed.

Further, with respect to the fluctuation of the pressing force caused by the rotation of the substrate 2, and the fluctuation of the pressing force caused by sliding the processing head in the radial direction of the substrate 2, that is, the substrate 2
The pressing force fluctuates due to the influence of the circumferential waviness, the straightness in the radial direction, and the warp. However, in response to these, the amount of fluctuation of the pressing force is immediately corrected by the command of the control device 17 to correct the pressing force. Can be corrected by.

When the first machining head reciprocates a set number of times, the machining head H1 moves backward (moves to the right in FIG. 1), and the supply of machining fluid from 60 is stopped.

Next, as shown in FIGS. 3 and 4, the rotary scrubber 61 'which was at the broken line position rises to 61, which is the solid line position, and the scrubber drive motor M drives this rotary scrubber 61'.
61 rotates. The substrate 2 also rotates, the cleaning liquid is supplied from the supply unit 60, and the substrate 2 is cleaned. When this cleaning is completed, the rotary scrubber 61 descends to the broken line position 61 ', and the supply of the cleaning liquid is stopped.

Then, in order to carry out the second polishing step, the second processing head H2 arranged on the side opposite to the first processing head H1 moves forward through the substrate support 1 of FIG. 1 (a). , The first processing head H by this processing head
The substrate 2 is processed in the same manner as 1.

That is, at the same time when the substrate is rotated by the motor 3, the second processing head H2 is oscillated by the oscillating motor 16 at the set oscillating amplitude, and the polishing tape drive unit 7 applies the polishing tapes 62a and 62b to the constant force. And the pressure applied to the substrate is adjusted to the set second pressure, and when the reciprocating table 63 is reciprocated by the reciprocating means, the tapes 62a and 62b are applied to the surface of the substrate 2. The existing fine protrusions are removed and smoothed.

During this time, the substrate drive motor 3 adjusts the rotation speed of the substrate 2 so that the relative speed between the substrate 2 and the second polishing tape becomes the set second relative speed. While the processing is proceeding in this way, the processing liquid is continuously supplied from the supply unit 60 to the substrate. Then, when the second machining head H2 reciprocates the set number of times of reciprocation, this machining head retracts (moves to the left side in FIG. 1) and the supply of the machining liquid is stopped. Finally, the substrate 2
When the substrate is cleaned by the substrate cleaning means S, the substrate processing apparatus is turned off.

When the substrate 2 is removed from the substrate support 1, the desired fine grooves are formed. In addition, magnetic media, protective film,
By forming the lubricating film, it is possible to obtain a magnetic disk having excellent sliding characteristics.

(3) Example of substrate polishing by the above apparatus:
A specific example in which fine grooves are formed in the substrate 2 that is Ni-P plated to a thickness of about 10 μm on an Al alloy substrate will be described with reference to FIGS. 5 and 6.

[0102] Figure 5, the first machining head H1 enlarged sectional curve diagram showing an example of a surface shape of the processed substrate (first polishing step) of the substrate processing apparatus according to FIG. 1, FIG. 6, further It is an expanded sectional curve view showing an example of the surface texture of the substrate processed with the 2nd processing head H2 (2nd polish process).

The first polishing tape 4 is made of Al ₂ having a particle size of 4 μm.
O ₃ abrasive grain, the first pressure is 10N, the first relative speed is 4m
/ Sec, the oscillation amplitude is 1 mm, the substrate 2 is processed by the first processing head H1 while supplying the water-soluble cutting fluid, and the depth of the surface of the substrate 2 as shown in FIG. V
Although a fine groove of about 100 nm was formed, there was a ridge (fine protrusion) with a height H of about 30 nm, and the ridge height was uneven. The surface roughness is 6～7NmR _a, symmetry R _sk sectional curve was -0.3. Also,
In the three-dimensional load curve, the cut area ratio at the cut surface of 5 nm from the top of the surface shape was 0.1% or less.

A second polishing step was applied after the above first polishing step. The second polishing tape is Al with a grain size of 1 μm
₂ O ₃ abrasive grains, second pressure 4N, second relative speed 8m
/ Sec, the oscillation amplitude was 1 mm, and the substrate 2 washed with pure water was processed by the second processing head H2 while supplying the water-soluble cutting fluid. The surface of the substrate 2 was as shown in FIG. As shown, the depth V of the fine groove was maintained at about 100 nm, the height H of the protrusion was reduced to about 10 nm or less, and the variation was small. The surface roughness is 6～7NmR _a, symmetry R _sk sectional curve was -1.5. In the three-dimensional load curve, the cut area ratio at the cut surface of 5 nm from the top of the surface shape was 0.8%.

According to the embodiment described above, since the second machining head can remove only the raised portion generated in the shoulder portion of the fine groove, the fine groove depth V is 20.
There is an effect that it is possible to form a smooth surface in which the height H of the protrusion (fine protrusion) is reduced to -100 nm.
Furthermore, if the processing conditions such as the grain size of the polishing tape, the material of the abrasive grains, the number of reciprocating slides on the substrate, and the pressing force are changed, any fine groove can be formed.

(4) Application of the above substrate to a magnetic disk:
By applying this method, using the above substrate as a base substrate, as shown in the sectional structure of the disk in FIG.
A thin film magnetic disk 80 in which a non-magnetic metal underlayer film 31, a magnetic medium film 32, a carbon protective film 33 and a lubricating film 34 are formed on 30.
Has good head flying characteristics, and is extremely excellent in reliability and stability.

Various characteristics of the thin film magnetic disk having the fine grooves of the present invention will be described in detail below together with comparative examples. That is, the height of the fine protrusions is several nm to several tens nm, the surface roughness is several nm to several tens nm _Ra , and the symmetry R _{sk of the} sectional curve is negative, preferably -0.7 or less, and more preferably -1 or less. On the surface or in the three-dimensional load curve, a cut surface at a depth corresponding to the amount of top deformation received by the head load during CSS from the top of the fine protrusion, practically 5 to 5 from the top.
A comparison is made between the magnetic disk of the base substrate and the magnetic disk of the other base substrate, which is composed of the surface having a cut area ratio of the cut surface at 10 nm of 0.1 to 10%.

FIG. 25 is a result of three-dimensionally measuring the textured surface according to the present invention, and FIG. 26 is a conventional textured surface measured by the same method. What is clear by comparing these figures is that in the case of FIG.
The surface condition is very smooth.

Explaining again with reference to FIGS. 13, 14 and 19, these are texture-processed by variously changing the processing conditions such as the grain size of the polishing tape, the number of reciprocations of the processing head, the pressing force, etc. the height and surface shape similar non-magnetic metal film described above and the base substrate was changed, the magnetic medium film, the thin film magnetic disks forming the carbon protective film further lubricating film, influence the head flying characteristics, the head adhesive , Again C
It is the result of examining the influence of the deformation amount of the surface texture (fine protrusion) and the head tangential force by the SS test.

As shown in FIG. 13, when the height of the fine protrusion is several nm (2 to 3 nm) or less, for example, in the case of a base substrate close to the polished surface, the head floating characteristic is good, but the head adhesive force is As a result, the problem of head adhesion increases, the gimbal that supports the head is damaged, and the substrate rotation drive motor is overloaded, resulting in an accident that the substrate cannot rotate.

When the height of the fine protrusion is several tens of nm or more, for example, 90 nm or more, the head adhesion is small and the head adhesion problem does not occur, but the head flying characteristic is poor and the head A crash accident occurred. When the height of the fine protrusions was in the range of 3 to 10 nm, the flying height was 0.15 μm, the flying height was stable, and the head adhesion was small, resulting in highly reliable flying characteristics.

As shown in FIG. 14, with respect to the symmetry R _sk , the characteristic is improved in a negative value region, preferably −0.7 or less, and practically −1 to −2. Furthermore, the relationship between the three-dimensional load ratio and the head flying characteristics and head adhesiveness (measured by tangential force) is as described above with reference to FIG.

[0112] Further, in the conventional textured surface shown in FIG. 26, the surface roughness is 6NmR _a, in 3-dimensional load curve, cutting area ratio of the cut surface in 5nm from the top is 0.08
%, The surface pressure of each fine protrusion due to the head load is large, and the sliding wear of the fine protrusion due to the head is remarkable along with the number of CSSs as shown by the curve D shown in FIG. Damage to the CSS
The head tangential force increased with the number of times, resulting in head crash.

[0113] In the textured surface according to the invention shown in FIG. 25, the surface roughness is 6NmR _a, the cutting area ratio of the cut surface in 5nm from the top in the 3-dimensional load curve
It was 0.1-10%. In this case, as shown by the curve C in FIG. 19, the head tangential force hardly increases even if the number of CSSs increases significantly to 30,000, and very stable and highly reliable CSS characteristics are obtained. It was In this case, on the surface of the disk that slid on the head slider, there was almost no change from the initial state, and almost no damage to the lubricant or the carbon protective film was observed.

[0114] The surface roughness is 6NmR _a, the contact area of the three-dimensional load curve, when the cutting area ratio of the cut surface in 5nm from the top of the surface is 15%, the magnetic head and the disk surface Since the head adhesion force at the start of CSS is large, the gimbal that supports the head is damaged when the disk is driven to rotate, and the motor for rotating the board is overloaded, causing an accident that the board cannot rotate.

In the above embodiments, the method of forming fine grooves and fine protrusions using the polishing tape was described, and the advantages of various characteristics of the thin film magnetic disk using this base substrate were shown.
The same effect can be obtained not only by the polishing tape but also by a cutting method, a grinding method, a surface processing method such as lapping and polishing, a surface treatment method such as etching and sandblasting, and a pattern forming method of a dry process. Further, even when the above processing methods are combined, the same effect can be obtained.

As one embodiment of the present invention, the width of the polishing tape is narrower than the width of the processed surface of the substrate, and the contact roller for pressing the polishing tape is reciprocated in the radial direction of the substrate. The substrate surface was processed while rocking, but the width of the polishing tape was made closer to the width of the surface to be processed of the substrate, or a polishing tape with a width larger than the width of the surface to be processed was used and shaken in the radial direction of the substrate. Even if the substrate is processed without moving or swinging, the same effect can be obtained.

Further, the above texture processing is performed by Ni-P.
The same effect can be obtained by applying to an Al substrate, a non-magnetic metal underlayer, or a protective film surface in addition to the plated undersubstrate.

(5) Advantages of the Embodiment: As described in detail above, according to this embodiment, it is possible to form a highly precise fine groove with extremely small fine protrusions on the Ni-P plated base substrate. The processing method and the apparatus used directly for implementing this method have made it possible to obtain a magnetic disk having excellent CSS characteristics even when the head flying height is as small as 0.1 μm.

That is, on the surface of the magnetic disk substrate, the height number
nm to several tens of nanometers of fine protrusions, surface roughness of several nanometers to several tens of nm _Ra ,
And on the surface where the symmetry R _{sk of the} cross-section curve is −0.7 or less, or on the three-dimensional load curve, from the top of the fine protrusion to C
Since it can be formed on a cut surface at a depth equivalent to the amount of top deformation received by the head load during SS, practically a surface having a cut area ratio of 0.1 to 10% of the cut surface at 5 to 10 nm from the top. In the CSS characteristic in which the magnetic head repeatedly contacts the disk surface intermittently, the head load is received by the large number of fine protrusions described above, and the surface pressure at each fine protrusion is small, resulting in deformation of the fine protrusions. , Sliding wear is reduced.

Further, deterioration of the protective film and the lubricating film formed on the fine protrusions is small, and sliding debris due to CSS is
Since the fine grooves are avoided especially in the deep groove portions, the sliding resistance is remarkably improved.

Further, in this substrate processing apparatus, by using the parallel leaf spring, the strain gauge and the pressure correction piezoelectric actuator, the pressure applied to the substrate by the contact roller is very small, and it is always uniform regardless of the shape accuracy of the substrate. Therefore, stable and uniform fine grooves can be formed over the entire surface of the substrate, and the fine protrusions of the fine grooves formed on the Ni-P plated base substrate are removed in minute amounts, so that the fine protrusions can be highly accurately formed. Can be smoothed.

Further, by the substrate processing apparatus for controlling the minute pressure, not only the fine grooves on the surface of the underlying substrate but also the fine projections on the surface of the completed magnetic disk, for example, the surface of the carbon protective film can be made fine. The fine protrusions can be reliably removed by cutting and removing each amount, and the carbon protective film around the fine protrusions and the surface forming film such as the magnetic medium are not damaged. Therefore, it is possible to obtain a very smooth surface with good surface accuracy.

[0123]

As described above, according to the present invention, the CSS characteristics can be remarkably improved even if the flying height of the head is smaller than that of the prior art, and it is suitable for high density and large capacity without causing a head crash. It has become possible to realize a highly reliable magnetic disk . Further, it is possible to realize an improved manufacturing method in which a cutting surface load ratio based on a three-dimensional load curve of a processed surface is used as an evaluation index in a processed layer, and the first and second polishing steps in the manufacturing method are highly controlled. By realizing it with the processing device having the first and second processing heads and the cleaning means, it is possible to perform highly accurate surface processing and realize the highly reliable disk .

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a substrate processing apparatus of the present invention.

2A and 2B are a plan view and a partial cross-sectional plan view showing a main part centering around a head of this apparatus.

FIG. 3 is a front view showing details of the substrate cleaning means in FIG.

FIG. 4 is a side view of the substrate cleaning means.

5 is a first processing head H of the substrate processing apparatus according to FIG.
2 is an enlarged sectional curve diagram showing an example of the surface of the substrate processed in 1.

FIG. 6 is an enlarged sectional curve diagram showing an example of the surface of the substrate further processed by the second processing head H2.

FIG. 7 is a front view showing a conventional substrate processing apparatus for forming fine grooves.

FIG. 8 is a side view of this device.

FIG. 9 is a cross-sectional configuration diagram of a thin film magnetic disk using the underlying substrate of the present invention.

FIG. 10 is a cross-sectional configuration diagram of a conventional thin film magnetic disk.

FIG. 11 is an explanatory view of a sectional shape of a fine groove.

FIG. 12 is an explanatory diagram of a conventional substrate processing apparatus.

FIG. 13 is a characteristic diagram in which the relationship between the height R _{p of the} fine protrusion, the head flying characteristic, and the head tangential force is investigated.

FIG. 14 is a characteristic diagram that examines the relationship between the symmetry R _sk , the head flying characteristic, and the head tangential force.

FIG. 15 is a characteristic diagram showing a change in the cross-sectional shape of the surface, which is measured by a high-resolution SEM for a minute change in the nanometer order on the substrate surface by CSS, (a) is before CSS, (b) is FIG. 6 is a characteristic diagram showing cross-sectional shapes after CSS.

FIG. 16 is a three-dimensional load curve of the pole surface of the substrate before and after CSS.

FIG. 17 is a characteristic diagram showing a cross-sectional shape of the substrate surface of the present invention.

18 is a characteristic diagram showing a cross-sectional shape of the surface of a magnetic disk having a magnetic medium formed on the substrate of FIG.

FIG. 19 is a characteristic diagram showing the relationship between the number of CSS times and head tangential force.

FIG. 20 is a partial cross-sectional perspective view showing the outline of a magnetic disk device to which the present invention is applied.

FIG. 21 is an explanatory diagram showing a relative relationship between a magnetic disk and a magnetic head.

FIG. 22 is a perspective view of a head slider showing the shape of a magnetic head.

FIG. 23 is a diagram showing the relationship between the head and the disk surface in CSS, and is a state diagram when the disk is stopped and when it is rotated.

FIG. 24 is a principle diagram in which SEM is applied as a method for measuring a three-dimensional surface of a textured surface.

FIG. 25 is a three-dimensional view of a textured surface of a magnetic disk according to the present invention.

FIG. 26 is a diagram in which a conventional textured surface is three-dimensionally displayed.

FIG. 27 is an explanatory view showing a relationship between a cross-sectional shape of a textured surface and a three-dimensional load curve and explaining a correlation with a CSS characteristic.

FIG. 28 is an explanatory view showing the relationship between the cross-sectional shape of the textured surface and the three-dimensional load curve and explaining the correlation with the CSS characteristics.

FIG. 29 is an explanatory diagram showing fine protrusions in the cross-sectional shape of the textured surface.

FIG. 30 is a diagram for explaining the property of the surface shape of the textured surface according to the present invention using a three-dimensional load curve.

FIG. 31 is a diagram for explaining the property of the surface shape of the textured surface according to the present invention using a three-dimensional load curve.

FIG. 32 is a characteristic diagram that examines the relationship between the three-dimensional sectional load ratio, the head flying characteristic, and the head tangential force.

[Explanation of Codes] 1 ... Rotating shaft for mounting substrate, 2 (30) ... Magnetic disk (substrate), 3 ... Motor for driving substrate, 4a, 4b ... First polishing tape, 5a, 5b ... Supply reel, 6a, 6b ... Winding reel, 7a, 7b ... Winding motor, 8, 9 ... Contact roller, 10, 11 ... Parallel leaf spring, 12, 13 ... Strain gauge, 14 ... Pressurizing motor, 15 ... Reciprocating motor, 17 ... Control device, 18a, 18b ... Braking torque motor, 21 ... Screw, 22 ... Reciprocating carriage, 24 ... Screw, 31 ... Non-magnetic metal base film, 32 ... Magnetic medium film, 33 ... Protective film, 34 (83) ... Lubrication film, 50 ... Pressure compensation piezoelectric actuator, 60 ... Liquid supply part, 61 (61 ') ... Rotary scrubber, 62 ... Second polishing tape, 63 ... Reciprocating carriage, 65 ... Liquid tank, 80 ... Magnetic disk (Completed product), 81 ... Magnetic head, 82 ... Head slider sliding surface, 85 ... Magnetic disk device, H1 ... First processing head H2 ... second machining head, R ... reciprocating means, S ... cleaning means, W ... rocking means.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiki Kato 2880 Kozu, Odawara-shi, Kanagawa Stock company Hitachi Odawara factory (72) Inventor Noriaki Okamoto 502 Kitsumachi, Tsuchiura-shi, Ibaraki Hiritsu Seisakusho Co., Ltd. In the laboratory

Claims (1)

[Claims] 1. A magnetic disk comprising a magnetic film for recording information formed on a non-magnetic substrate for recording information, a protective film and a lubricating film, and the surface shape of the magnetic disk is substantially smooth. In the three-dimensional curve representing the surface shape of the magnetic disk, the load ratio is 0.1 to 1 on the cut surface having a depth corresponding to the top deformation amount from the top of the surface.
A magnetic disk characterized by being set to 0%.