JPH02285515A - Magnetic disk and method and apparatus for producing this disk and magnetic disk device - Google Patents

Abstract

PURPOSE:To improve CSS characteristics even if the floating quantity of a head is decreased and to hardly generate a head crash by providing a nonmagnetic substrate which is specified in the load ratio on the cut surface of the depth corresponding to the deformation quantity of the peak part receiving from the head load at the time of the CSS from the summit part on the surface. CONSTITUTION:An underlying film 31 consisting of a nonmagnetic metal of a Cr system and a magnetic thin-film medium 32 consisting of a Co-Ni system are successively formed respectively by sputtering on the disk substrate 30 and further, a carbon protective layer 33 is formed thereon and a lubricating film 34 is formed thereon in succession thereto. The surface of the surface working layer of the nonmagnetic metallic substrate has the projecting parts nearly smoothed in the surface as the surface characteristics of the projecting parts on this layer and the load ratio on the cut surface of the depth corresponding to the deformation quantity of the peak part receiving from the head load at the time of the CSS from the summit part of the surface in the three-dimensional load curve indicating the surface shape thereof is specified to 0.1 to 10%. The CSS characteristics are improved in this way and the generation of the head crash is obviated even if the floating quantity of the head is decreased.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to a magnetic disk, a method and apparatus for manufacturing the same, and a magnetic disk device. The present invention also relates to a method and apparatus for manufacturing the same, and a magnetic disk device.

[Conventional technology]

In high-density, large-capacity magnetic disks, the magnetic recording medium formed on a non-magnetic disk substrate is produced by depositing magnetic metal on the disk substrate by vapor deposition or sputtering, instead of using a so-called coating film made of conventional magnetic powder bonded with resin. A shift has been made to so-called thin-film magnetic metal layers that are directly formed as thin films. and,
When driving a magnetic disk device, a magnetic disk (hereinafter simply referred to as a disk) that is in a stationary state must be
A magnetic head (hereinafter simply referred to as head) with a specific load is elastically contacted and pressed, and at the start,
As the disk rotates, the head begins to slide on the disk surface, and when the rotation speed reaches a high speed of several 1000 revolutions per minute, the head starts to slide on the disk surface. The head flies a predetermined distance above the disk surface. The disk device is configured such that the head can move arbitrarily in the radial direction of the disk in this floating state, and data can be read and written at any position on the disk surface. On the other hand, when the disk is stopped, the disk starts to rotate at a reduced speed, but the head starts sliding on the disk surface again, comes into contact with the disk surface, and stops in a pressed state. This type of drive method is usually called contact star 1~stop (contact star 1~stop).
It is called tS top (abbreviated as CSS). That is, in the C S S driving method, the sliding surface of the head is in a state of stopping the disk surface → sliding → flying → sliding → stopping, and this cycle is repeated every time the head is driven. In order to facilitate the flying performance of this head, fine grooves are generally formed on the surface of the disk in the circumferential direction of rotation. FIG. 10 shows the cross-sectional structure of the disk 80. Normally, this type of groove is formed by performing a surface polishing process called texturing on the surface of the disk substrate 30 before forming a magnetic film. A thin magnetic metal layer 32 is formed on the surface of the substrate having such an uneven surface, and a protective film 33, a lubricating film (not shown), etc. are formed on top of the thin magnetic metal layer 32 to imitate the surface condition of the underlying substrate. Grooves will be formed on the disk surface.

Texturing of the surface of the disk substrate is an important polishing technique when adopting the CSS active method. By setting the value of
As a result of the S test, no scratches were observed on the disk surface after 20,000 cycles, but head crashes are likely to occur when the maximum surface roughness exceeds 0.1 seconds, and if no texture processing is applied. After 5000 CSS cycles, scratches occur,
It is said that he caused a head crash.

To give an example of a conventional texture processing device, for example, as described in Japanese Patent Application Laid-Open No. 54-23294,
There is a technology as shown in Figure 2. In other words, the contact roller 8 applies the polishing tape 4, which runs up and down according to the rotation of the reel 6, on both sides of the rotating disk substrate 30.
There is known an apparatus that simultaneously processes both surfaces of a disk substrate by sliding the substrate back and forth in the radial direction of the disk substrate while pressing each other in the direction of the arrow. 7 and 8 respectively show the positional relationship between the substrate 30 and the polishing tape 4 running on it.
The figure is a front view, and FIG. 8 is a schematic side view thereof. According to this type of texture processing, fine grooves 37 with no polishing unevenness can be formed using the polishing tape as shown in FIG. - A stable raised portion 36 is generated, and this raised portion 36
There was a problem in that small protrusions remained on the surface.

Therefore, as shown in JP-A No. 62-248133, for example, a normal texturing process is performed in the first polishing process, and then polishing is performed in a second polishing process using abrasive grains smaller than that in the first polishing process. Accordingly, a method has been proposed in which only the protrusions formed on the substrate surface in the first polishing step are removed without removing the fine grooves formed on the disk substrate surface.

[Problem to be solved by the invention]

As mentioned above, there have been regulations regarding the maximum surface roughness for fine grooves formed on the disk substrate through texture processing, and regulations regarding protrusions on the substrate that take head flying characteristics into consideration. The optimum surface properties of the textured surface for the properties and head adhesion properties are still unknown, and problems such as head crushing have not yet been solved.

In particular, the recent progress in increasing the density and capacity of magnetic disks has been remarkable, and as a result, the flying height of the head above the disk surface due to CSS has become smaller. The gap between the disk surface and the head sliding surface (so-called flying height) is 0.
Narrower conditions are required, such as 2 μm or less. Therefore, in order to achieve this severe condition by texturing, it is necessary to make the height of the protrusion raised on the shoulder by groove formation equal to or less than this flying height, so that when the head flies, the head will not touch the protrusion. Contact with the disk must be avoided, and extremely strict disk surface properties are required. If contact between the protrusion and the head sliding surface is simply to be avoided, the shape of the head sliding surface, head load, disk rotation speed, etc. may be changed to ensure a sufficient head flying height. However, as mentioned above, as the recording density of disk devices increases, it is necessary to reduce the flying height (ideally, the head and magnetic film should be brought as close together as possible), and the impact caused by the sliding of the head. In order to reduce the amount of deformation and friction wear of the head, the height of the protrusions is made uniform to increase the contact area with the sliding surface of the head, and deep grooves are also used to avoid the sliding layer. It is necessary to have the following.

Therefore, as mentioned above, conventionally, in order to make the heights of the protrusions produced by groove formation uniform, the process of polishing the disk substrate surface is divided into two steps, the first and second steps, and the second step is to remove the protrusions. However, it is unclear about the optimal texture processing surface properties for CSS characteristics and head visual characteristics when the flying height of the head is small, and problems such as Hen 1~Crash still remain. Not resolved. In other words, if you try to make the heights of the protrusions uniform by thorough polishing, the sliding area of the head against the disk surface (strictly speaking, the polished surface that contacts the head sliding surface of the protrusion) will increase. The flying ability of the head decreases,
Furthermore, the lubricant on the disk surface (generally a lubricant film is formed) and moisture in the atmosphere adhere to the head sliding surface, and these are accumulated due to surface tension, and the head sliding surface eventually touches the disk surface. This creates a new problem in that the disk becomes stuck, making it impossible to rotate the disk and damaging the head.

Therefore, the purpose of the present invention is to solve these conventional problems, and the first purpose is to provide an improved system that has excellent CSS characteristics and is less likely to cause a head crash even if the head flying height is smaller than the conventional one. The second objective is to provide a method for manufacturing the magnetic disk, the third objective is to provide an apparatus for manufacturing the magnetic disk, and the fourth objective is to provide a magnetic disk in which the magnetic disk and a magnetic head drive device are integrally mounted. The purpose of the present invention is to provide magnetic disk devices.

[Means for solving problems]

A first object of the present invention is to provide (1) a non-magnetic substrate having a surface-treated layer having a finely uneven shape on at least its main surface; and at least a thin film sequentially formed on the non-magnetic substrate following the uneven surface. In a magnetic disk comprising a magnetic metal layer and a protective layer thereof, the surface texture of the convex portion in the non-magnetic metal substrate surface treatment layer includes a convex portion with a substantially smooth surface; In the three-dimensional load curve shown, a magnetic disk comprising a non-magnetic substrate has a load ratio of 0.1 to 10% at a cut surface from the top of the surface to a depth equivalent to the amount of top deformation received from the head load during CSS. Preferably, (2) a non-magnetic substrate having a surface-treated layer having a fine unevenness on at least its main surface, and at least a thin magnetic metal film sequentially formed on the non-magnetic substrate following the uneven surface. In the magnetic disk comprising a layer and a protective layer thereof, the surface texture of the protrusions in the non-magnetic metal substrate surface treatment layer is a protrusion with a height of several nanometers to several tens of nanometers and a substantially smooth surface. and a non-magnetic substrate having a load ratio of 0.1 to 10% at a cut plane at a depth of 5 to 10 nm from the top of the convex surface in a three-dimensional load curve representing the surface shape of the non-magnetic substrate. More preferably, by a magnetic disk comprising:
(3) Surface shape 3 of the non-magnetic metal surface treatment layer
By means of a magnetic disk whose dimensional load curve has a flat shape at the extreme surface, and more preferably (4)
The surface texture of the non-magnetic metal substrate surface treatment layer has a depth of at least 1 mm within a width equivalent to the head slider sliding surface.
This is achieved by a magnetic tissue having a 100n concave fine deep groove and Rsk≦-0,7 indicating the symmetry of the cross-sectional curve.

The second object of the present invention is to (1) polish the surface of a non-magnetic substrate, which has been mirror-finished in advance, in a two-step polishing process of the first and second steps, thereby forming an uneven layer on the surface of the non-magnetic substrate; A method for manufacturing a magnetic disk comprising the steps of: forming a thin film magnetic metal layer on the textured layer formed by the polishing step; and forming a protective film on the thin film magnetic metal layer. As the first polishing step, a fine groove having a predetermined deep groove is provided as a recess within a unit width at least equivalent to the sliding surface width of the magnetic head on the substrate, and as the second polishing step, a fine groove having a predetermined deep groove is provided as a recess. When polishing a convex portion that has been formed on the shoulder portion by a predetermined amount from the top thereof and smoothing the surface of the convex portion, the surface shape is expressed as the end point detection of the amount of polishing from the top portion. In the dimensional load curve, find the load ratio at the cut surface at a depth equivalent to the amount of top deformation that the top of the surface convex part receives due to the head load during CSS, and finish polishing when this value is within the range of 0.1 to 10%. Preferably, (2) the surface of the non-magnetic substrate, which has been mirror-finished in advance, is polished in a first and second two-step polishing process to form irregularities on the surface of the non-magnetic substrate. Manufacturing a magnetic disk comprising the steps of forming a processed layer, forming a thin magnetic metal layer on the uneven processed layer formed by the polishing process, and forming a protective film on the thin magnetic metal layer. In the method, as the first polishing step, a fine groove having a predetermined deep groove is provided as a recess within a unit width at least equivalent to the sliding surface width of the magnetic head on the substrate, and as the second polishing step, Polishing a predetermined amount of the convex portion formed on the shoulder portion by forming the fine groove from the top thereof,
When smoothing the surface of such a convex portion, the load ratio at a cut plane at a depth of 5 to 10 nm from the top of the convex surface in a three-dimensional load curve representing the surface shape is used to detect the end point of the amount of polishing from the top. This value is 0.1
More preferably, (3) as the first polishing step, a first polishing tape is applied to both surfaces of the non-magnetic substrate at the same time. The polishing tape is moved in the circumferential direction of the non-magnetic substrate and reciprocated while being oscillated in the radial direction. After processing the non-magnetic substrate by rotating the magnetic substrate so that the relative speed with the first polishing tape becomes a predetermined first relative speed, the non-magnetic substrate is cleaned, and then as the second polishing step, A second polishing tape having an abrasive grain size smaller than that of the first polishing tape is simultaneously pressed onto both surfaces of the non-magnetic substrate with a second pressing force smaller than the first pressing force, and this polishing tape is While traveling in the circumferential direction of the non-magnetic substrate and reciprocating while swinging in the radial direction, while supplying machining liquid to the polishing surface,
After processing the non-magnetic substrate by rotating the non-magnetic substrate so that the relative speed with the second polishing tape becomes a predetermined second relative speed that is larger than the first relative speed, cleaning the non-magnetic substrate This is achieved by a method of manufacturing a magnetic disk as described above.

A third object of the present invention is to provide a substrate support capable of rotatably supporting a disk substrate, and a polishing tape applied with a predetermined pressure for simultaneously performing a first polishing process on both sides of the substrate. A first contact roller unit having a contact roller unit capable of being pressed by a roller, a tape winding motor for winding up the polishing tape, and a reciprocating means capable of swinging the contact roller unit in a radial direction of the substrate. a second processing head having the same structure as the first processing head disposed on the opposite side of the substrate support for performing a second polishing process; a substrate rotating means capable of rotating the substrate so that the relative speed of the substrate becomes a predetermined value;
A substrate cleaning means disposed between the surface processing heads and capable of cleaning the substrate, and a control device capable of controlling at least the operation timing of the surface processing head and the substrate rotation means. This is achieved by a magnetic disk manufacturing device.

The fourth object of the present invention is (1) a plurality of magnetic disks are mounted on the same rotating shaft at predetermined intervals, and a magnetic head is mounted on at least one surface of each of these disks. Information is recorded using the CSS drive method in which the head slider elastically contacts and slides with a predetermined pressing force when the disk is stationary and in the initial state of rotation, floats due to high-speed rotation of the disk, and is driven back and forth in the radial direction of the disk. In a magnetic disk device equipped with a head drive device that performs reading, the surface texture of the magnetic disk sliding surface in the relationship between the magnetic disk and a head slider that slides and flies above the disk is a magnetic disk substrate made of a non-magnetic substrate. It has a surface texture that mimics the surface condition of the surface roughening layer, and the surface of this disk substrate has convex portions with an almost smooth surface. Preferably, by a magnetic disk device comprising a non-magnetic substrate having a load ratio of 0.1 to 10% at a cut surface at a depth corresponding to the amount of top deformation received from the head load during CSS from the top of the disk, (2) The properties of the surface of the disk substrate are as follows:
It has a convex portion with a height of several nanometers to several tens of nanometers and a smoothed surface, and in a three-dimensional load curve representing the surface shape, the load ratio in a cross section at a depth of 5 nm from the top of the convex surface is More preferably, by a magnetic disk device having a non-magnetic substrate of 0.1 to 10%, (
3) More preferably, the three-dimensional load curve as the property of the disk substrate surface has a flat shape at the extreme surface; Even more preferably, the magnetic disk device has a concave fine deep groove having a depth of at least 1100 nm within the width of the moving surface, and Rsk≦-0,7 indicating symmetry of the cross-sectional curve, (5)
When the contact area between the head slider and the disk surface is S, the head load is W, the surface pressure W/S is, and the yield strength of the fine convexities on the disk substrate surface due to cSS drive is σ, the head slider This initial state on the disk sliding surface is achieved by a magnetic disk device having a disk sliding surface that is in contact with the relationship σ≧W/S.

Here, the study results of the present inventors that led to the above-mentioned present invention will be explained in detail below.

With CSS, the top surface of the disk is heated by nanometers (nm) by the sliding of the head slider equipped with the magnetic head.
) This change causes the disk surface to become smoother, increasing the horizontal resistance force exerted on the head and causing a head crash, or causing the head to stick when stopped at CSS, resulting in accidents such as the inability of the disk to rotate. experienced. Therefore, for the textured surface of a disk substrate, simply specifying the maximum surface roughness or the height of the convex part cannot explain the CSS characteristics of the magnetic disk or the sliding characteristics such as head crash resistance. I found out that I can't do it. Because the overall properties, including the shape of the convex parts from the average surface and the shape of the grooves in the surface unevenness, and the properties of the three-dimensional load curve are more important than the maximum surface roughness. It has been noticed that no consideration has been given in the past, and that the most important aspect of the surface unevenness of the underlying substrate, which should improve head crash and CSS characteristics, has not been presented.

As shown in a partially cross-sectional perspective view in FIG. 20, the magnetic disk device 85 generally includes a plurality of magnetic disks 80 mounted and fixed on the same rotating shaft at predetermined intervals, and information is stored on both sides of each disk. A magnetic head 81 for recording and reading is installed. FIG. 21 is an explanatory diagram 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. When arm 8 is in a stationary state and an initial state of rotation,
The elastic force of 4 is pressed onto the disk surface, causing contact and sliding, but when the disk rotates at high speed, the head 8
1 is in a state of floating with a submicron flying height due to the effect of airflow with the disk 80. FIG. 23 specifically shows these states. FIG. 23(a) shows the contact state when the disk is stopped and sliding, and FIG. 23(b) shows the contact state when the disk is stopped and sliding.
This shows the floating state of the disk when it rotates at high speed.

The shape of the head 81 is such that, as shown in FIG. 22, there are sliders 82 on both sides of the head that slide on the disk surface.
has.

The dimensions of this head slider surface 82 are, for example, a width W of 0.4 mm and a length Q of 4 mm, and the head slider is installed so that the length Q direction is the same direction as the circumferential direction of the disk. has been done. Therefore, the uneven shape of the disk surface is at least equal to the Herad slider width W, that is, 0.
The problem is the shape for dimensions of 4 mm or dimensions of 0.4 mm or more.

Here, a method for measuring the cross-sectional shape of the textured substrate surface will be described. This cross-sectional shape was created using a stylus with a surface roughness of 0. Using a stylus of IIM x 2.577 m, measure the length of the head slider width W (for example, 0.4 + nm) or the head slider 1 in the radial direction of the base substrate.
This is a curve measured at a length of 30.4 mm or more. The output signal from the Talystep was A/D converted and determined by computer processing with a sampling interval of 40 nm.

As shown in FIG. 31, the fine protrusions refer to the above cross-sectional curve measured in the radial direction of the disk substrate with respect to the textured surface formed approximately in the circumferential direction or spirally. , indicates a convex direction from the center line C of the cross-sectional curve, that is, individual peaks of minute height (referred to as convex portions in the present invention). Further, the height RP of the minute protrusion represents the distance between the highest peak of each mountain and the center line in a unit length measured in the radial direction.

In addition, as the surface quality of the textured surface, the symmetry of the textured cross-sectional curve was expressed as Rsk obtained by the following equation according to a well-known display method. The cross-sectional curve is expressed as a function Y (i
), it can be expressed by the following general formula.

When the general formula, Rsk representing symmetry, is negative, it means that the groove component of the cross-sectional curve is large, and when it is positive, it means that the protrusion component is large. In the case of RskO, the protrusion component and the groove component are equal and the cross-sectional curve is symmetrical with respect to the center line C.

Here, a method for three-dimensionally measuring the uneven state of a textured surface will be explained using FIG. 32. Figure 3 (
a) is STM (ScanningTu), which will be described later.
This shows the results of the three-dimensional surface measurement G of the textured surface using (Nneling Mj, croscope), and from this, the three-dimensional surface is divided at equal intervals on a plane H (a plane at depth Δh1 from the outermost surface) parallel to the average plane. FIG. 32(b) is a graph of the area ratio obtained by dividing these cut areas by the total area at the reference plane E, which is deeper than the textured layer, for each cut plane. That is, FIG. 32(b) is a load curve expressed in three dimensions.

Generally, this three-dimensional load curve is an Abbott load curve with respect to a two-dimensional cross-sectional curve, as shown in FIG.
BOTT-FIRESTONE (ORBEARING
RATIO) The content is similar to CURVE, but it is expanded into three dimensions. This Abono 1-load curve is used to evaluate the sliding characteristics of bearings and the like. The present inventors have observed and measured the contact phenomenon between the head and the disk in detail, including the condition of the head sliding surface, the condition of the disk surface, and the movement condition of the head and disk in CSS. We have found that a three-dimensional load curve using STM is very effective as a method for highly accurate evaluation of the disk surface with respect to its sliding characteristics.

In other words, this load curve is as shown in FIG.
As shown in , 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 of the surface, and the total cutting area of each three-dimensional shape by this cutting plane H is calculated. A curve is shown in which the value obtained by dividing E by the reference area E is expressed as a percentage for each cut surface. At the top of the surface shape, the area cut by the cutting plane is small and the area ratio is small. In other words, if there is a sliding body on this surface, at the beginning of sliding, only the top of the surface shape supports the sliding body, so the pressure receiving area is small and the surface pressure is large, so the top part slides by friction due to the sliding body. , easy to cause wear and deformation. Therefore, on a surface with a large cutting area ratio at the top of the surface shape, that is, in a three-dimensional load curve, on a surface where the cutting area ratio is small and the slope of the load curve is small, the pressure receiving area is at the initial state. Since the surface pressure of each fine protrusion that supports the sliding body is reduced, the sliding properties are improved.

In this way, the three-dimensional load curve is one of the evaluation methods for expressing the load capacity of the surface of the sliding body on which it is slid.

In addition, S
EM (Scanning E 1ectron M
Figure 24 shows the principle of measurement using an icroscope. In other words, to explain according to the same figure, two 2
The incident angle O of the electron probe is determined by the secondary electron detectors A and B.
Detect signal intensities a and b at (tilt of sample), and signal intensities an and b at incident angle O (irradiation on a plane).
As n, the following general formula tanθ=k((a2-b2)/(an+bn)2)(
Here k is a constant) Find θ from: By integrating the inclination of the sample determined in this way, the surface shape in the X-axis direction can be measured. For example, an example of this type of measuring device is an electron beam surface morphology analyzer manufactured by Elionix.

Furthermore, by scanning in the Y direction, the shape of the three-dimensional surface can be measured.

The present invention has been made based on the following knowledge, and the details of the study will be explained in more detail below.

As is well known, the substrate of the magnetic disk is a non-magnetic substrate such as aluminum alloy, anodized aluminum, Nj
-It consists of a substrate made of aluminum alloy coated with P plating, etc., or glass or plastic, and as a factor in improving its properties, it is necessary to form a large number of uniform microgrooves and microprotrusions on its surface. .

These fine grooves and fine protrusions are created by forming fine grooves on the substrate surface using a cutting and polishing tool such as a diamond cutting tool or fine abrasive grains. A raised portion 36 is formed. The height of the protrusions of these fine protrusions is set by the depth and size of the grooves 37, and the number of fine grooves is set by processing conditions such as the density of fine abrasive grains and tool feed.

Here, the essential points regarding the surface properties of magnetic disks are:
without causing head crash, and with good electrical characteristics and CSS
The objective is to satisfy various characteristics of the magnetic disk, such as characteristics and head adhesion characteristics. To achieve high density magnetic disks, the head flying gap becomes narrower, so the disk surface is required to be ultra-smooth to avoid collisions between the head and the disk.

However, due to the need to shorten head access time, head 8
As shown in FIG. 23, the contact star 1 and the disk 80 come into contact with each other when stopped, and float as the disk rotates.
(abbreviated as). Therefore, if the surface of the disk 80 is a smooth surface, that is, if the surface roughness is very small, the head and disk will stick together due to the lubricant 83 on the disk surface or moisture in the atmosphere when the disk is stopped, and the head will not be supported when the disk rotates. There were problems with the gimbal and arm being damaged and the rotation becoming impossible. FIG. 13, FIG. 14, and FIG. 34 show the results of experiments conducted by the present inventors. The height of fine protrusions, the symmetry of the texture cross-sectional curve, the three-dimensional cross-sectional load ratio, the head flying characteristics, and the head adhesion force due to the texture processing (details will be explained later) formed on the base substrate using abrasive tape. shows the relationship between

That is, FIG. 13 shows the relationship between the protrusion height, the head flying height H6° as the flying characteristic, and the head tangential force Ft as an index of the head adhesive force, and FIG. 14 shows the relationship between the symmetry Rsk,
Furthermore, FIG. 34 shows the three-dimensional cross-sectional load ratio (at a contact surface depth of 5 nm from the top) as well as the flying height Hto
and head tangential force F, respectively, and the measurement method is as follows.

(i) Measurement of head flying height H5°: In principle, it has the same configuration as the disk device 85 shown in FIG. 20. An AE sensor is mounted on the head 81. Reference numeral 81 starts floating and measures the disk rotation speed at which the output signal from the AE sensor detecting the state of contact with the disk surface suddenly decreases.

On the other hand, the flying characteristics of the head depending on the number of rotations of the disk are investigated in advance, and the flying start height H5° of the head is measured.

(...) Measurement of head tangential force F: The sliding resistance force of the head during one revolution (lr/m1n) of the disk is measured with a strain gauge installed on the support arm 84 of the head 81.

From this result, it can be seen that there is an effective range of surface properties suitable for simultaneously satisfying both head flying characteristics and head adhesive force, such as a small flying height Hto and a small tangential force F. In other words, if we look at the microprotrusions RP, as shown in FIG. 13, in the range of several nm to several tens of nm,
More preferably, it is within the region indicated by an arrow, and as shown in FIG. 14, the symmetry Rsk is preferably a region where the value is negative, preferably a region where Rsk≦−0,7 as indicated by the arrow. In addition, looking at the relationship with the three-dimensional cross-sectional load ratio, as shown in Figure 34, the lower limit of the effective load ratio is regulated by the flying characteristics, and the upper limit is regulated by the head adhesive force (expressed by the head tangential force F). and preferably 0.1 to 10%
, more preferably 0.24 to 8.5%.

Furthermore, the relationship between the above-mentioned surface texture and CSS characteristics will be explained using FIGS. 27 to 30.

FIG. 27 shows a cross-sectional shape of a surface of a base substrate textured using fine abrasive grains, in which fine protrusions are present with variations.

As shown in Fig. 28, the three-dimensional load curve of this textured surface corresponds to the range where the cutting area ratio is small, that is, the second
The slope of the load curve is large in the range of part A in Figure 8. When the magnetic head repeats CSS on the surface as shown in Fig. 27, the fine protrusions have little contact with the head slider surface, which causes the surface pressure W/S (W: head load, S2 beaded slider and disk surface As the actual contact area with the surface increases, wear or deformation occurs rapidly, resulting in a lubricating film several nanometers thick or several tens of nanometers thick formed on the base substrate with minute protrusions.
The protective film of 100 nm is seriously damaged.

On the other hand, the wear or deformation of the microscopic protrusions due to CSS is as follows when σ<W/S, where the yield strength of the microscopic protrusions is σ.
It occurs intensely and decreases when σ≧W/S.

Therefore, as the fine protrusions are worn away or deformed by CSS, the actual contact area increases, and the above-mentioned σ
The true contact area S satisfies ≧W/S, and at this time,
If the protective film and lubricant film were formed without damage,
There is almost no wear or deformation of minute protrusions, resulting in a stable surface. Therefore, the surface of the base substrate having the cross-sectional shape shown in FIG. 27 is further processed to form a model trapezoidal shape with smoothed minute protrusions as shown in FIG. 29.

By increasing the true contact area between the head slider and the disk surface and creating a surface shape with a true contact area such that σ≧W/S in the initial state, the surface pressure of the minute protrusions will be reduced, so CS
S causes almost no wear or deformation of the small side protrusions, resulting in a stable and highly reliable surface as a magnetic disk. The three-dimensional load curve of the surface shape shown in Fig. 29 becomes as shown in Fig. 30, and as shown in part A of Fig. 30, the slope of the load curve at the extreme surface is extremely small. I understand.

In experiments conducted by the present inventors, for a conventional textured surface having a three-dimensional surface shape as shown in FIG.
For example, a surface corresponding to the Herad slider surface (for example, 0.4
The three-dimensional load curve in mm x 0.4 mm surface is:
The cutting area ratio at a depth of 5 nm to 10 nm from the top of the surface shape, that is, a depth of 5 nm to 10 nm at the cut surface, is 0.1% or less, and in a magnetic disk using such a base substrate, the number of CSS cycles is 2000 or less. A head crash occurred. On the other hand, the textured surface of the present invention as shown in FIG. 29, that is, the depth of the cut surface is 5 nm to 10 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%,
When the number of CSS cycles was zoooo or more, both the protective film and the lubricating film maintained their respective functions, and a stable surface condition was maintained.

Furthermore, detailed changes in the magnetic disk surface due to CSS were investigated. In experiments by the present inventors, the textured substrate was subjected to the contact start/stop CSS test, and the surface shape measured from the SEM observation of the disk surface subjected to the CSS test shown in Fig. 15, From the three-dimensional load curve of the disk pole surface shown in Fig. 16, the tops of the fine protrusions in the initial state are smoothed by repeated sliding of the magnetic head, and the fine protrusions where the head and disk come into contact at this time are smoothed out by repeated sliding of the magnetic head. It was found that the area of 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. In addition, the load curve B in Fig. 16 is the same as that shown in Fig. 15 (
The characteristics in the initial state of a) and the load curve A are:
The characteristics after repeated sliding in FIG. 15(b) are shown. For example, when the number of CSS cycles is 20,000, the surface changes by a fine 5 to 10 nm height from the top of the initial state due to contact with the slider surface of the magnetic head, as shown in part A of FIG. 15(b). When the protrusions change and the three-dimensional load curve of the disk surface at this time shown in FIG. 16 shows that the minute protrusions change by 5 to 10 nm from the top of the initial state,
The cutting area in contact with the magnetic head ranged from 0.1% to several percent. In other words, if the height of the fine protrusions is several tens of nanometers or more, it will deteriorate the flying characteristics of the magnetic head and cause a head crash.Also, even if the fine protrusions are several nanometers or less, if the cutting area ratio is small. , the load area of the substrate surface that supports the head load when the head slides in the CSS test, that is, the micro protrusions, is small and is immediately smoothed with the number of CSS cycles, and the head tangential force increases, making it more likely to cause a head crash. Become.

In addition, if the load area of the fine protrusions is small, the surface pressure of the fine protrusions that receives the head load increases, so the fine protrusions tend to decrease or wear out, and the lubricant layer of several nm thick formed on the substrate surface If the protective film layer is easily damaged, and if the cutting area ratio is 10% or more and the load area is large, there will be little change in the minute protrusions on the substrate caused by the magnetic head, but the contact area will increase, so lubricants and The head tends to stick due to the influence of moisture in the atmosphere, and the sliding resistance of the magnetic head during CSS increases, resulting in problems such as damage to the gimbal and arm of the magnetic head, and difficulty in rotating the disk.

Therefore, the surface properties of the textured substrate should be determined by considering the flying characteristics of the head, head load, and surface changes due to frictional wear caused by head sliding, and from the above results, the height of the fine protrusions should be from several nanometers to several nanometers. Onm, surface roughness is several nm
R, ~ several tens of nanometers Ra, and the symmetry Rsk of the cross-sectional curve is negative, preferably -0.7 or less, more preferably -11
On the following surface or three-dimensional load curve, cut plane from the top of the minute protrusion at a depth equivalent to the amount of top deformation received by the head load during CSS, in practice, cut at 5 to 10 r + m from the top. The cutting area ratio of the plane is 0.1 to 10
% is desirable.

From this point of view, the optimal surface for a magnetic disk substrate is a cross-sectional shape of a substrate surface that has been textured, by forming pseudo-circumferential fine grooves on the substrate surface, as shown in Figure 6. , the height of the fine protrusions is several nanometers to several tens of nanometers, and the surface roughness is several nanometers to several tens of nanometers.
nmRa (preferably 5 nm to 9 nm Ra), the symmetry of the cross-sectional curve Rsk≦-1, and the cutting area ratio at 5 to 10 nm from the top is 0.1 to 10%.

In addition, in order to maintain smooth head sliding on the disk, deep grooves V as shown in FIG. It is important that this deep groove (2) always exists, and it has been found that it is effective if the depth of this deep groove (2) is at least 1100 nm.

[Effect]

The height of the minute protrusions formed on the magnetic disk substrate is several n.
m to several tens of nm, and the surface roughness is several 1 mRa to several tens of nanometers.
mRa, and the symmetry Rsk of the cross-sectional curve is -0.7 or less,
Preferably, the surface is 11 or less, especially in a three-dimensional load curve, a cut surface from the top of the minute protrusion at a depth equivalent to the amount of top deformation received by the head load during CSS, practically, 5 to 5 from the top. The cutting area ratio of the cut surface at 10 nm is 0.
A disk surface having a surface texture of 1 to 10% comes into contact with the slider surface of the head during CSS of the magnetic head and receives a favorable head load. In addition, the surface unevenness of the disk surface maintains the lubricant film applied on the magnetic disk surface, and at the same time prevents adhesion with the magnetic head, avoiding the sliding layer caused by the head sliding in the deep grooves on the disk surface. It has an effect. Furthermore, the cutting area ratio is 0.1 to 10 nm at a practically preferable 5 to 10 nm from the top where a large number of minute protrusions are in contact with the Herad slider surface and the surface changes due to head sliding.
Since it is 10%, the surface pressure of each fine protrusion is small, and the change of the fine protrusion due to repeated CSS, that is, deformation and wear is small, and the initial state of the surface is maintained. Furthermore, the height of the fine protrusions is several nanometers to several tens of nanometers, which is extremely small compared to the magnetic head's flying gap (the gap between the magnetic head and the magnetic disk surface in a steady state) of 150 to 250 nm, and the height of the magnetic disk. Even if assembly accuracy, rotational accuracy, and flying fluctuations of the magnetic head are taken into account, the magnetic head flies with sufficient margin, and head crashes due to collisions of the magnetic heads do not occur.

Therefore, the thickness number n of the film formed on the surface of the magnetic disk
There is almost no wear or damage to the protective film or lubricant film, no head sticking occurs, no increase in head tangential force due to repeated CSS, and magnetic disks with high reliability in terms of head flying characteristics and anti-sliding characteristics. Obtainable.

〔Example〕

Example 1 As a disk substrate, an aluminum alloy plate with an inner diameter of 40 mm and an outer diameter of 130 mm was used, and both sides were coated with N1-
After P plating and smooth polishing to a surface roughness of 2 to 3 nm Ra or less, the groove shape is shaped using a polishing tape, as shown in Figure 17, and the height of the fine protrusions formed on the shoulders of the fine grooves is several nm.
It was polished to have a uniform surface roughness of ~10 nm, a surface roughness of 5 to 8 nm Ra, and a cross-sectional curve symmetry Rsk of -1 to 2. The cross-sectional shape in Fig. 17 was measured using a surface roughness meter,
Using Talystep, the stylus shape is 0. Measurements were taken perpendicular to the groove using IX 2.5-. Specific methods for manufacturing these disk substrates will be described in detail later.

As shown in FIG. 9, which shows the cross-sectional structure of the magnetic disk, the disk substrate thus obtained has a thickness of approximately 300 nm.
A Cr-based non-magnetic metal base film 31 with a thickness of m and a Co-Ni-based magnetic thin film medium 32 with a thickness of about 60 nm are sequentially formed by sputtering, and then a carbon protective film 33 with a thickness of about 50 nm is formed. Lubricant ++x34 was sequentially formed.

The surface shape of the magnetic disk thus manufactured, as shown in FIG. 18, is almost the same as that of the disk substrate shown in FIG. 17, with a surface roughness of 5.5 nmRa (
5.3 nmR on the substrate), and the height RP of the fine protrusion is 1
9 nm (20 nm), and the cross-sectional symmetry Rsk was also almost the same.

A plurality of these magnetic disks are incorporated in the same way as the magnetic disk device 85 shown in FIG.
As a result of a flying test, no contact between the head and the disk surface was detected, indicating good flying characteristics, and almost no change in the shape of the magnetic disk surface was observed due to the number of CSS operations.

FIG. 19 is a characteristic curve diagram showing the relationship between the number of CSSs and the head tangential force (in newtons N) in this example in comparison with a conventional comparative example. Curve C is the example of the present example, and curve C is the comparative example.As is clear from this figure, in the case of this example, there was almost no increase in the head tangential force even after 30,000 CSS cycles, and there was no problem with head adhesion. This eliminates the problem, and significantly improves the reliability of magnetic disks and magnetic disk devices.

As a comparative example, as shown in the curved line, in a magnetic disk in which microgrooves with a cross-sectional shape as shown in FIG. 5 are formed in the base substrate using the conventional technology, the head tangential force increases with the number of CSSs, resulting in damage to the magnetic head and damage to the magnetic head. There were problems such as head crashes. It can also be seen that the cross-sectional shape of the disk surface changes significantly with the number of CSSs compared to the present invention.

Here, the method for manufacturing the substrate of this example will be specifically described below.

N1-P plating films were formed on both sides of the aluminum alloy disk substrate to a thickness of 10/ffi by electroless plating and polished to a surface roughness of 0.01 R1, laX or less. Then,
As a first polishing step, the surface is processed with a polishing tape made of alumina abrasive grains having a grain size of #3000 to form fine grooves on the surface of the N1-P plated substrate.

In this surface processing method, for example, as shown in Japanese Patent Laid-Open No. 54-23294, polishing tape 4 is pressed onto both sides of a substrate 30 shown in FIG. 12 with a contact roller 8, and the polishing tape is applied while rotating the substrate. While winding up with reel 6,
The polishing tape is slid back and forth on the substrate so as to slide over the entire surface of the substrate, forming approximately circumferential or spiral fine grooves on both surfaces of the substrate.

Next, abnormal minute protrusions with a height of 1100 nm or more are generated in several places on the substrate surface, and are particularly likely to occur in the shoulders of deep grooves.
This becomes a cause of deterioration of head flying characteristics, and furthermore, a cause of head crash accidents. Therefore, in the second polishing step, the surface was processed in the same manner as in the first polishing step using a polishing tape having a smaller particle size than the polishing tape in the first polishing step. As a result of surface processing in this second polishing step,
The height of the abnormal minute protrusions is reduced, and the tops of many minute protrusions are smoothed, and as shown in FIG. 6, the minute protrusions H are smoothed, and deep grooves V are periodically formed. It was possible to form a surface with a cross-sectional shape.

Note that between the first and second polishing steps, a substrate surface cleaning step was provided to remove dirt on the substrate surface such as processing debris from the surface processing in the first step. In the second polishing step, as a means of detecting the polishing end point, the three-dimensional load curve described above is obtained based on the principle of SEM shown in FIG. The end point was defined as a point where the load ratio of the cut area obtained by cutting at a depth of 5 to 10 nm from the top of the section satisfied the condition of 0.1 to 10%.

Embodiment 2 Hereinafter, an embodiment of a disk substrate surface texturing apparatus suitable for manufacturing the magnetic disk of the present invention will be described with reference to the drawings.

(i) Description of processing device configuration: Fig. 1 is a front view showing an embodiment of the device for texturing the surface of a substrate according to the present invention, Fig. 2 is a plan view showing the main parts of this device, and Fig. 3 1 is a front view showing details of the substrate cleaning means in FIG. 1, and FIG. 4 is a side view of this substrate cleaning means.

First, an overview of this substrate processing apparatus will be explained using FIG. 1(a).
A set of contact roller units 1-C1 capable of simultaneously pressing the first abrasive tape 4 with a predetermined pressure on both sides of the tape winding motor 7 for winding up the first abrasive tape 4. , contact roller unit C
a swinging means W capable of swinging in the radial direction of the substrate 2;
, a reciprocating means R capable of reciprocating the contact roller unit C in the radial direction of the substrate 2, and a first processing head H1 disposed on one side of the substrate support; Head I (having the same configuration as 1, disposed on the opposite side of the first processing head H1 with respect to the substrate support,
A pair of processing heads consisting of a second processing head H2 equipped with a second polishing tape having a smaller abrasive grain size than the first polishing chip instead of the first polishing chip;
The substrate rotation motor 3 is disposed between the surface processing head and the substrate rotation means that can rotate the substrate at a predetermined speed relative to the second polishing tape, and is capable of cleaning the substrate. Substrate cleaning means S and the surface processing head H1
, H2, a substrate drive motor 3, and a control device 17 capable of controlling a substrate cleaning means S.

Note that FIG. 1(b) shows the first head H1 in FIG. 1(a).
This is an enlarged view of the main parts.

Further, the processing head H1 will be explained in detail by taking the above-mentioned processing head H1 as an example, using FIG.

This processing head H1 moves the substrate 2 to the reciprocating means R.
A pair of parallel leaf springs 10 supported movably in the axial direction of
, 11 and the parallel plate springs 1o and 11, a pressure moving means 23 that eliminates the influence of pack tension due to winding of the polishing tape 4 and enables setting of a predetermined minute pressure force, and substrate processing. Pressure force correction means 5 that compensates with good responsiveness minute fluctuations in pressure force due to the influence of substrate shape accuracy at the time
0 (for example, a piezoelectric actuator, etc.) and contact rollers 8, 9 attached to the parallel leaf springs 10, 11, installed on both sides of the substrate 2, and with their central axes oriented in the radial direction of the substrate 2. and the reciprocating means R
a polishing tape drive device 7 attached to the substrate and sliding the polishing tape 4 between the substrate and the contact roller; stress measuring means 12, 13 attached to the parallel leaf springs 10, 11; A control device 17 is provided which controls the pressurizing force moving means 23 and the pressurizing force correcting means 50 according to the output of the means.

Therefore, in this substrate processing apparatus, fluctuations in pack tension due to winding of the polishing tape, which is a cause of minute fluctuations in the pressing force, are avoided due to fluctuations in the pack tension caused by the supply and take-up reels 5.
, 6 changes as the diameter of the abrasive tape is wound during processing, and the tension of the tape changes, causing the pressing force to fluctuate. If this amount of variation is always measured by the stress measuring means 12 and the parallel plate springs 10.11 are adjusted by the pressure moving means 23 according to the amount of change, the contact roller 8.9, the pressure applied to the substrate 2 can be kept constant. In addition, in order to improve the responsiveness of the correction of the pressure force against fluctuations in the pressure force due to undulations in the circumferential direction of the substrate or warpage in the radial direction of the substrate during processing, a pressure correction means 50 such as a piezoelectric actuator is used. It is possible to correct minute pressing forces with good responsiveness. The above functions make it possible to form fine grooves with high precision.

The first processing head H1 is mounted on one side (the first
(on the right side in Figure (a)), and fine grooves (for example, a depth of about 0.1/min) are formed in the first polishing process on both sides of the substrate
This is used to form a 7 m long fine groove. This processing head H1 is a tape winder that winds the first polishing tape 4 attached to each of a pair of contact roller units C disposed on both sides of the substrate 2 from below to above. It consists of a swinging means W capable of swinging the motor 7a and the contact roller unit C in the radial direction, and a reciprocating means R capable of reciprocating the motor 7a and the contact roller unit C in the radial direction. Each of the contact roller units C can apply a predetermined pressing force to the contact roller 8 via the contact roller 8 used to press the first polishing tape 4 to the substrate 2 and the parallel leaf spring 10. A strain gauge 12 for detecting the pressing force is bonded to the parallel plate spring 10, and the pressurizing motor 14 connects the parallel plate spring 10 to a substrate. By being displaced in the direction perpendicular to the two planes, pressure force can be applied, and the force correction piezoelectric actuator 50 can compensate for minute fluctuations in pressure force during machining with good responsiveness. ing. The swinging means W includes a swinging motor 16 and a crank 55 that connects the shaft of the swinging motor 16 and the first processing head H1. Further, the reciprocating means R screwly transmits the rotation of the reciprocating motor 15 to the first machining head H1 to reciprocate this machining head.

As described above, the second processing head H2 has the same configuration as the first processing head except that a second polishing tape is attached instead of the first polishing tape, and the second processing head H2 has the same configuration as the first processing head, and It is disposed on the side (left side in Figure 1(a)) and is used for the second polishing process to remove the raised microgrooves formed on both sides of the substrate by the first processing head. It is.

Furthermore, the configuration of the processing head will be explained in detail with reference to FIG. 1 is a horizontally installed rotating shaft for mounting a substrate; 2 is a substrate as a workpiece; 3 is a rattling motor for rotating the rotating shaft; 21 is a rotatably supported screw; 1
5 is a reciprocating motor for rotating the screw 21, 22
is a reciprocating table supported movably in the radial direction of the board, that is, in the direction of arrow A; the reciprocating table 22 is provided with a female screw, and the female screw is screwed into the screw 21;
1. The motor 15 constitutes a reciprocating means R. 23
16 is a vibration device fixed to the reciprocating table 22, and the vibrating device 16 vibrates the movable body 23 with minute amplitude.

To explain in more detail with reference to FIG. 2, 24 is a screw rotatably supported by the movable body 23, 14 is a pressurizing motor for rotating the screw 24, and 10.11 is a substrate mounted on the movable body 23.
A pair of parallel plate springs supported movably in the axial direction of the arrow B, that is, in the direction of the arrow B.
1 is provided with a female screw, and the female screw is screwed into a screw 24, and the screw 24 and the motor 14 constitute a pressurizing moving means. Further, if the substrate has bad waviness in the circumferential direction or warp in the radial direction, the pressing force will fluctuate during processing. For this reason, the parallel leaf springs 10.11 are installed on a support base 51 provided with a pressurizing force correction piezoelectric actuator 50, and
A female thread is provided in the holder, and this female thread is screwed into the screw 24 as described above. 8.9 is a contact roller rotatably attached to a parallel leaf spring 10.11, and the contact rollers 8.9 are installed on both sides of the substrate 2, and are attached with their central axes oriented in the radial direction of the substrate. HLa, tab is a braking torque motor attached to the moving body 23, 5a
, 5b are supply reels attached to the output shafts of the motors 18a and 18b, 7a and 7b are winding motors attached to the moving body 23, and 6a and 6b are winding reels attached to the output shafts of the motors 7a and 7b. Reels 4a and 4b are abrasive tapes in which fine abrasive grains such as diamond abrasive grains and alumina abrasive grains are adhered and held on a base material such as a polyester film with a binder such as resin, and both ends of the abrasive tapes 4a and 4b are supply reels. 5a, 5b, take-up reel 6a, 6b
motors 18a, 18b, supply reels 5a, 5b, motors 7a, 7b, take-up reels 6a, 6.
b constitutes a polishing tape drive device, in which polishing tapes 4a and 4b pass between the substrate and the contact roller.

12.13 is a strain gauge attached to the parallel leaf spring 10.11, 17 is a control device that controls the motor 3, 14, 15, etc., and the control device 17 controls the motor 14, the motor 14, etc. according to the output of the strain gauge 12.13. and controls the pressing force correction piezoelectric actuator to move the parallel plate springs 10 and 11.

Next, the substrate cleaning means S shown in FIG. 1(a) will be specifically explained below with reference to FIGS. 3 and 4.

FIG. 3 is a front view for explaining the main parts thereof, and FIG. 4 is a side view thereof.

The substrate cleaning means includes a rotating scrubber (made of brush or sponge) 61 that cleans both sides of the substrate at the same time, and a scrubber drive motor M that rotates the rotating scrubber 61.
It consists of an air cylinder (not shown) that can reciprocate the rotary scrubber between the broken line position 61' and the solid line position, and a liquid tank 65.

60 is a supply unit that supplies machining liquid and cleaning liquid.

(ii) Operation description of the above apparatus: First, the substrate 2 is placed on the substrate support 1 of the processing apparatus shown in FIG. 1(a).
Attach. Processing conditions such as pressing force, relative speed, vibration amplitude, and 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 motor 3 rotates the substrate, and at the same time, the first processing head H1 is oscillated by the oscillation motor 16 at a set oscillation amplitude, and the abrasive tape drive device 7 is used to rotate the abrasive tape. If the polishing tapes 4a and 4b are wound up with a constant force, the pressure applied to the substrate is adjusted to the first set pressure force, and the reciprocating table 22 is reciprocated by the reciprocating means R, the polishing tapes 4a and 4b By board 2
fine grooves are formed on the surface. During this time, the rotation speed of the substrate 2 is adjusted by the substrate drive motor 3 so that the relative speed between the substrate 2 and the first polishing tape 4 becomes the set first relative speed. While the machining is progressing in this manner, the machining liquid is continuously supplied from the supply unit 60 to the substrate.

Even if the tension of the polishing tapes 4a, 4b changes and the parallel leaf spring 10.11 deforms, the control device 17 controls the deformation of the parallel leaf spring 10.11 according to the output of the strain gauge 12.13. Since the motor 14 is controlled according to the amount of deformation, the parallel plate spring 10.11 maintains the pressing force of the contact roller 8.9 against the substrate 2 at a constant level regardless of fluctuations in the tension of the polishing tapes 4a, 4b. Since a small pressing force can be maintained at all times, small and uniform fine grooves can be formed. Furthermore, in response to fluctuations in the pressing force due to the rotation of the substrate 2, and fluctuations in the pressing force due to sliding of the processing head in the radial direction of the substrate 2, there are Although the pressurizing force fluctuates due to the effects of straightness and warpage, the amount of pressurizing force variation can be immediately corrected by the pressurizing force correction piezoelectric actuator 50 according to a command from the control device 17.

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

Next, as shown in FIGS. 3 and 4, the rotary scrubber 61', which was at the dashed line position, rises to the solid line position 61.
This rotating scrubber 61 is driven by the scrubber drive motor M.
rotates. The substrate 2 also rotates, cleaning liquid is supplied from the supply unit 60, and the substrate 2 is cleaned.

When this cleaning is completed, the rotary scrubber 61 moves to the position 6 shown by the broken line.
1' and the supply of cleaning liquid is stopped.

Then, in order to carry out the second polishing step, as shown in FIG.
), a second processing head H2 disposed on the opposite side to the first processing head H1 moves forward, and this processing head supports the substrate 2 in the same manner as the first processing head H1. is processed. That is, at the same time as the motor 3 rotates the substrate, the second processing eight 1-N2 is oscillated by the oscillation motor 16 at a set oscillation amplitude, and the abrasive tape drive device 7 applies a constant force to the abrasive tapes 62a and 62b. The pressure applied to the substrate is adjusted to the set second pressure force, and the reciprocating table 63 is wound by the reciprocating means.
When the substrate 2 is reciprocated, fine protrusions existing on the surface of the substrate 2 are removed and smoothed by the polishing tapes 62a and 62b. During this time, the rotation speed of the substrate 2 is adjusted by the substrate drive motor 3 so that the relative speed between the substrate 2 and the second polishing tape becomes a set second relative speed. While the machining is progressing in this manner, the machining 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, this machining head moves backward (moves to the left in FIG. 1) and the supply of machining fluid is stopped. Finally, when the substrate 2 is cleaned by the substrate cleaning means S in the same manner as before, the substrate processing apparatus is turned off.

When the substrate 2 is removed from the substrate support 1, desired fine grooves are formed. Furthermore, by forming a magnetic medium, a protective film, and a lubricating film, a magnetic disk with excellent sliding characteristics can be obtained.

(ni) Example of substrate polishing using the above apparatus: A I will explain using

FIG. 5 is an enlarged cross-sectional curve diagram showing an example of the surface texture of a substrate processed by the first processing head H1 (first polishing step) of the substrate processing apparatus according to FIG. 1, and FIG. FIG. 2 is an enlarged cross-sectional curve diagram showing an example of the surface properties of a substrate processed by No. 2 processing head H2 (second polishing step).

The first polishing tape 4 includes An203 abrasive grains with a grain size of 4/Im.
The first pressing force is ION, the first relative speed is 4 m/see.
When the substrate 2 was processed with the first processing head H1 while supplying water-soluble cutting fluid with an amplitude of oscillation of 1 mm, the surface of the substrate 2 had a depth of 1 mm as shown in FIG. A fine groove with a diameter of about 100 nm was formed, but the height H was about 30 nm.
There were bulges (fine protrusions) of nm size, and the height of the bulges varied. Also, the surface roughness is 6~7n
mRa, and the symmetry Rsk of the cross-sectional curve was -0.3. Further, in the three-dimensional load curve, the cut area ratio at a cut plane of 5 nm from the top of the surface shape was 0.1% or less.

After the first polishing step described above, a second polishing step was applied. The second polishing tape was An20. with a grain size of 1 mm. Using abrasive grains, a second pressing force of 4 N, a second relative speed of 8 m/see, and a swing amplitude of 1 mm, the substrate 2 cleaned with pure water was subjected to a second process while supplying a water-soluble cutting fluid. processing head H2
As shown in FIG. 6, when the surface of the substrate 2 was processed, the depth V of the microgrooves was maintained at about 1100 nm, the height H of the bulge was reduced to about 10 nm or less, and the variation was small.

Further, the surface roughness was 6 to 7 nmRa, and the symmetry Rsk of the cross-sectional curve was -1.5. Further, in the three-dimensional load curve, the cut area ratio at a cut plane 5 nm from the top of the surface shape was 0.8%.

According to the embodiment described above, the second processing head can remove only the raised portions generated at the shoulders of the fine grooves, so that the fine groove depth V is 20 to 1100.
n. There is an effect that a smooth surface with a reduced height H of bulges (fine protrusions) can be formed. Further, by changing the processing conditions such as the grain size of the polishing tape, the abrasive grain material, the number of times of reciprocating sliding on the substrate, and the pressing force, it is possible to form any fine grooves.

(iv) Application of the above substrate to a magnetic disk: By applying this method, using the above substrate as a base substrate, a non-magnetic metal base film 31 is formed on this substrate 30 as shown in FIG. 9, which shows the cross-sectional structure of the disk. , a magnetic medium film 32, a carbon protective film 33, and a thin film magnetic disk 8 on which a lubricating film 34 is formed.
0 has good head flying characteristics and extremely excellent reliability and stability.

Various characteristics of the thin film magnetic disk in which fine grooves are formed according to the present invention will be described in detail below along with comparative examples.

That is, the height of the fine protrusions is several nanometers to several tens of nanometers, the surface roughness is several nanometers to several tens of nanometers R, and the symmetry Rsk of the cross-sectional curve is negative, preferably -0.7 or less, more preferably -11 In the following surface or three-dimensional load curve, a cut surface from the top of the minute protrusion at a depth equivalent to the amount of top deformation received by the head load during CSS, in practical terms,
The cutting area ratio of the cut surface at 5 to 10 nm from the top is 0.1
A comparison is shown between a magnetic disk having a base substrate having a surface of ~10% and a magnetic disk having a base substrate other than that.

FIG. 25 shows the results of three-dimensional measurement of a textured surface according to the present invention, and FIG. 26 shows a conventional textured surface measured using a similar method.

What is clear from comparing these figures is that the 25th aspect of the present invention
In the case shown in the figure, the surface condition is extremely smooth.

To explain again using FIGS. 13, 14, and 19, these are texture-processed by varying the processing conditions such as the grain size of the polishing tape, the number of reciprocations of the processing head, and the pressing force, and the fine protrusions are For thin-film magnetic disks in which the same non-magnetic metal film, magnetic medium film, carbon protective film, and lubricant film as described above were formed on base substrates with different heights and surface properties, the effects on head flying characteristics and head adhesion were evaluated. It also shows the results of investigating the amount of deformation of the surface texture (fine protrusions) and the influence of head tangential force through CSS tests. As shown in Fig. 13, when the height of the fine protrusions is less than a few meters (2 to 3 nm), for example, when the base substrate is close to the polished surface, the head flying characteristics are good, but the head adhesion force increases. However, problems with head adhesion occurred, resulting in damage to the gimbal that supports the head, and an overload on the motor for driving the rotation of the substrate, resulting in an accident in which the substrate could no longer be rotated. Furthermore, if the height of the fine protrusions is several tens of nm or more, for example, if the fine protrusions are 90 nm or more, the head adhesion force is small and no head adhesion problem occurs, but the head flying characteristics are poor and head crash accidents occur. occured. When the height of minute protrusions is 3 to 10 nm, the head flying gap is 0.1 nm.
It floats stably at 5-, and the head adhesion is small.
□□□ Highly reliable levitation characteristics were obtained.

As shown in FIG. 14, with respect to the symmetry Rsk, the characteristics are improved in a negative value region, preferably −0, 7 or less, and practically preferably −1 to −2.

Furthermore, regarding the relationship between the three-dimensional load ratio and these head flying characteristics and head adhesion (measured by tangential force),
This is as explained earlier with reference to FIG.

Furthermore, in the conventional textured surface shown in Fig. 26, the surface roughness is 6 nmRa, and in the three-dimensional load curve, the cutting area ratio of the cut surface at 5 nm from the top is 0.08%.
The contact pressure of each minute protrusion due to the head load is large, and as shown by the curve shown in Figure 19, the sliding wear of the minute protrusion due to the head is significant as the number of CSS increases, and the lubricant and carbon protective film The damage to the CSS becomes large.
The head tangential force increased with the number of times, resulting in a head crash. Furthermore, in the textured surface according to the present invention shown in FIG. 25, the surface roughness was 6 nmRa, and the cut area ratio of the cut surface at 5 nm from the top in the three-dimensional load curve was 0.1 to 10%. . In this case, as shown by curve C in Fig. 19, even if the number of CSS increases significantly to 30,000 times, the head tangential force hardly increases, resulting in extremely stable and highly reliable CSS characteristics. Obtained. In this case, the surface of the disk that slid against the head slider was almost unchanged from its initial state, and almost no damage to the lubricant or carbon protective film was observed. Also, the surface roughness is 6nmRa
In the three-dimensional load curve, if the surface has a cutting area ratio of 15% at 5 nm from the top, the contact area between the magnetic head and the disk surface is large, and the head adhesion at the start of CSS is low. The increased force caused damage to the gimbal that supports the head when the disk was being rotated, and an overload was applied to the motor for driving the substrate rotation, resulting in an accident where the substrate could no longer be rotated.

In the above example, a method for forming micro grooves and micro protrusions using an abrasive tape was described, and the advantages of various characteristics of a thin film magnetic disk using this base substrate were shown. Similar effects can be obtained by processing methods, surface processing methods such as grinding, lapping, and polishing, surface treatment methods such as etching and sandblasting, and pattern forming methods using dry processes. Further, even when the above processing methods are combined, exactly the same effect can be obtained.

As an embodiment of the present invention, a polishing tape whose width is narrower than the width of the processed surface of the substrate is used, and a contact roller that presses the polishing tape is reciprocated and oscillated in the radial direction of the substrate. However, the width of the polishing tape should be brought closer to the width of the surface to be processed, or a polishing tape with a width larger than the width of the surface to be processed should be used, and the polishing tape should be swung in the radial direction of the substrate. Alternatively, the same effect can be obtained by processing the substrate without swinging.

Furthermore, the same effect can be obtained by applying the above texturing process to an An substrate, a nonmagnetic metal base film, or a protective film surface, in addition to the N1-P plated base substrate.

(V) Effects of Example: As explained in detail above, according to this example, N1-P
The head flying height can be as small as, for example, 0.17zn+, thanks to a substrate processing method that can form highly accurate microgrooves with extremely small microscopic protrusions on the plating base substrate, and equipment directly used to implement this method. It has also become possible to obtain magnetic disks with excellent CSS characteristics. In other words, the magnetic disk substrate surface has minute protrusions with a height of several nanometers to several tens of nanometers, a surface roughness of several nanometers to several tens of nanometers Ra, and a surface with a cross-sectional curve symmetry Rsk of -0.7 or less, or a three-dimensional surface. In the load curve, the cut surface from the top of the minute protrusion at a depth equivalent to the amount of top deformation received by the head load during CSS, practically speaking, the cut surface ratio of the cut surface at 5 to 10 nm from the top is 0.1. 10% of the disk surface, in CSS characteristics where the magnetic head repeatedly contacts the disk surface intermittently, the head load is received by the many minute protrusions mentioned above, and each of the minute protrusions The surface pressure on the parts is small, and the deformation of minute protrusions and sliding wear are reduced. Furthermore, there is little deterioration of the protective film or lubricant film formed on the fine protrusions, and since the CSS sliding layer is avoided in the deep grooves of the fine grooves, the anti-sliding properties are significantly improved.

Furthermore, by using parallel plate springs, strain gauges, and pressure-force compensation piezoelectric actuators in this substrate processing equipment, the pressure force of the contact roller against the substrate can be kept very small and always uniform regardless of the shape accuracy of the substrate. , it is possible to form stable and uniform microgrooves over the entire surface of the substrate, and since the microprotrusions of the microgrooves formed on the Ni-P plating base substrate are removed minute by minute, the microprotrusions can be smoothed with high precision. .

Furthermore, the substrate processing device that controls micro-pressure forces not only cuts micro grooves on the surface of the base substrate, but also cuts minute protrusions on the surface of the protective film, such as the carbon protective film, on the completed magnetic disk surface. The fine protrusions can be removed reliably, and the carbon protective film surrounding the fine protrusions and the surface-forming film of the magnetic medium, etc., are not damaged.

Therefore, a very smooth surface with good surface accuracy can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, CSS characteristics can be significantly improved even if the head flying height is smaller than before, and highly reliable magnetic fields suitable for high-density and large-capacity without head crashes can be achieved. It has become possible to realize disks and disk devices. In addition, we have realized an improved manufacturing method in which the cut surface load ratio according to the three-dimensional load curve of the processed surface is used as an evaluation index in the processed layer, and the first and second polishing steps in the manufacturing method are improved by highly controlled polishing. 1. By implementing a processing device equipped with a second processing head and a cleaning means, it is possible to perform highly accurate surface processing and to realize the disk and disk device with high reliability.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are front views showing an embodiment of the substrate processing apparatus of the present invention, and FIGS. 2(a) and 2(b) show the head of this apparatus. 3 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, and FIG. FIG. 5 is an enlarged cross-sectional curve diagram showing an example of the surface of a substrate processed by the first processing head H1 of the substrate processing apparatus according to FIG. 1, and FIG. 7 is a front view showing a conventional substrate processing device for forming fine grooves, FIG. 8 is a side view of this device, and FIG. FIG. 10 is a sectional diagram of a thin film magnetic disk using a base substrate. FIG. 10 is a sectional diagram of a conventional thin film magnetic disk. FIG. 11 is an explanatory diagram of the sectional shape of fine grooves. The explanatory diagrams of conventional substrate processing equipment, FIGS. 13, 14, and 34, all show the relationship between the height, symmetry, and three-dimensional cross-sectional load ratio of minute protrusions, and head flying characteristics and head tangential force. Figure 15, a characteristic diagram that examines the relationship, shows minute changes in the nanometer order on the substrate surface caused by CSS using a high-resolution SEM.
Figure 15 (,) is a characteristic diagram showing changes in the cross-sectional shape of the surface measured by
) are characteristic diagrams showing the cross-sectional shapes after CSS, the first
Figure 6 shows the three-dimensional load curve of the extreme surface of the board before and after CSS, and Figures 23 (a) and (b) show the relationship between the head and the disk surface in CSS, when the disk is stopped and when the disk is rotating. FIGS. 17 and 18 are characteristic diagrams showing the cross-sectional shapes of the substrate of the present invention and the surface of a magnetic disk on which a magnetic medium is formed, respectively. FIG.
Characteristic diagram showing the relationship between SS number and head tangential force, 2nd
0 is a partial cross-sectional perspective view schematically showing a magnetic disk device to which the present invention is applied, FIG. 21 is an explanatory diagram showing the relative relationship between a magnetic disk and a magnetic head, and FIG. 22 is a magnetic The head shape is shown in a perspective view of the head slider. Figure 24 is a diagram of the principle of applying SEM as a method for measuring the three-dimensional surface of the textured surface. Figure 25 is the texture of the magnetic disk according to the present invention. Figure 26 is a three-dimensional representation of the processed surface, Figure 26 is a three-dimensional representation of the conventional textured surface, Figures 27, 28, 29, 3
Figure 0 shows the relationship between the cross-sectional shape of the textured surface and the three-dimensional load curve, and is an explanatory diagram to explain the correlation with CSS characteristics. Figure 31 shows the fine protrusions in the cross-sectional shape of the textured surface. The explanatory diagrams shown in FIG. 32 and FIG. 33 are diagrams each illustrating the properties of the surface shape of the textured surface according to the present invention using a three-dimensional load curve. 1...Rotary shaft 2 for board mounting (30)...Magnetic disk (board) 3...Board drive motors 4a, 4b...First polishing tape 5a, 5b...Supply reel 6a, 6b ...Take-up reels 7a, 7b Take-up motor 8.9 Contact roller 10.11 Parallel plate spring 12.13...Strain gauge 14/Pressure motor 15...Reciprocating motor 17...Control device 18a , 18b...braking torque motor 2 screws
22... Reciprocating table 24... Screw
31...Nonmagnetic metal base film 32...Magnetic medium film 33.Protective film 34 (83)...Lubricating film 50...Pressure force correction piezoelectric actuator 60...Liquid supply section 61 (61'). ... Rotating scrubber 62 ... Second polishing tape 63 ... Reciprocating table 6
5...Liquid tank 80...Magnetic disk (finished product) 81...Magnetic head 82...Head slider sliding surface 85/Magnetic disk device Hl...First processing head H2...Second Processing head R...reciprocating means S...cleaning means W...swinging means

Claims (1)

[Scope of Claims] 1. A non-magnetic substrate having a surface-treated layer with fine irregularities on at least its main surface, and at least a thin magnetic metal layer sequentially formed on the non-magnetic substrate following the irregular surface. In the magnetic disk comprising the protective layer, the surface texture of the convex portion of the non-magnetic metal substrate surface treatment layer includes a convex portion whose surface is substantially smoothed, and a three-dimensional load representing the surface shape. A magnetic disk comprising a non-magnetic substrate having a load ratio of 0.1 to 10% in a cut plane from the top of the surface to a depth corresponding to the amount of top deformation received by the head load during CSS in the curve. 2. A non-magnetic substrate having a surface treatment layer with fine irregularities on at least its main surface, and at least a thin magnetic metal layer and its protective layer sequentially formed on the non-magnetic substrate following the irregular surface. In the magnetic desk, the surface texture of the convex portions in the non-magnetic metal substrate surface treatment layer includes convex portions with a height of several nm to several tens of nm and a substantially smooth surface, and the surface shape of the convex portions is In the three-dimensional load curve shown, 5 to 10 nm from the top of the convex surface
A magnetic disk comprising a non-magnetic substrate having a load ratio of 0.1 to 10% at a cut surface at a depth of . 3. The magnetic disk according to claim 1 or 2, wherein the three-dimensional load curve of the surface shape of the non-magnetic metal surface treatment layer has a flat shape at the extreme surface. 4. The surface properties of the non-magnetic metal substrate surface treatment layer include a concave fine deep groove with a depth of at least 100 nm within the width equivalent to the head slider sliding surface, and Rsk≦-0.7 indicating symmetry of the cross-sectional curve. The magnetic disk according to claim 1, 2 or 3, comprising: 5. A step of forming an uneven layer on the surface of the non-magnetic substrate by polishing the surface of the non-magnetic substrate, which has been mirror-finished in advance, in a first and second two-step polishing step; In the method for manufacturing a magnetic disk, the first polishing step includes the steps of: forming a thin magnetic metal layer on the textured layer; and forming a protective film on the thin magnetic metal layer. A fine groove having a predetermined deep groove is provided as a concave portion within a unit width equivalent to at least the sliding surface width of the magnetic head, and as the second polishing step, a protrusion formed on the shoulder portion of the fine groove by forming the fine groove is provided. When polishing a part by a predetermined amount from the top and smoothing the surface of the convex part, as an end point detection of the amount of polishing from the top, the top of the surface convex part is CSS in the three-dimensional load curve representing the surface shape. A method of manufacturing a magnetic disk comprising: determining a load ratio at a cut surface at a depth equivalent to the amount of top deformation received by a head load; and finishing polishing when this value falls within a range of 0.1 to 10%. 6. A step of forming an uneven layer on the surface of the non-magnetic substrate by polishing the surface of the non-magnetic substrate, which has been mirror-finished in advance, in a first and second two-step polishing step; In the method for manufacturing a magnetic disk, the first polishing step includes the steps of: forming a thin magnetic metal layer on the textured layer; and forming a protective film on the thin magnetic metal layer. A fine groove having a predetermined deep groove is provided as a concave portion within a unit width equivalent to at least the sliding surface width of the magnetic head, and as the second polishing step, a protrusion formed on the shoulder portion of the fine groove by forming the fine groove is provided. When polishing a predetermined amount from the top of the convex part to smooth the surface of the convex part, the end point of the amount of polishing from the top part is detected by polishing the surface of the convex part by a predetermined amount from the top of the convex part in the three-dimensional load curve representing the surface shape. A method for manufacturing a magnetic disk, which comprises determining a load ratio at a cut surface with a depth of ~10 nm, and finishing polishing when this value falls within a range of 0.1 to 10%. 7. As the first polishing step, press both sides of the non-magnetic substrate simultaneously with a first polishing tape with a predetermined first pressure force, and run this polishing tape in the circumferential direction of the non-magnetic substrate. At the same time, the non-magnetic substrate is reciprocated while being oscillated in the radial direction, and while supplying processing liquid to the polishing surface, the non-magnetic substrate is moved at a relative speed with respect to the first polishing tape to a predetermined first relative speed. After processing the non-magnetic substrate by rotating it, it is cleaned, and then in the second polishing step, a second polishing tape having a smaller abrasive grain size than the first polishing tape is simultaneously applied to both sides of the non-magnetic substrate. Pressing the polishing tape with a second pressure force that is smaller than the first pressure force, and causing the polishing tape to run in the circumferential direction of the non-magnetic substrate,
While reciprocating while swinging in the radial direction and supplying processing liquid to the polishing surface, the non-magnetic substrate is moved to a predetermined second polishing tape whose relative speed with respect to the second polishing tape is higher than the first relative speed. 7. The method of manufacturing a magnetic disk according to claim 5, wherein said non-magnetic substrate is processed by rotating it at a relative speed of , and then cleaned. 8. A substrate support capable of rotatably supporting a disk substrate, and capable of pressing a polishing tape with a predetermined pressure to simultaneously perform a first polishing process on both sides of the substrate. a contact roller unit, a tape winding motor for winding up the abrasive tape,
a first processing head having a reciprocating means capable of swinging the contact roller unit in the radial direction of the substrate; a second processing head having the same structure as the first processing head; a substrate rotating means capable of rotating the substrate at a predetermined speed relative to the polishing tape; A surface polishing processing apparatus comprising a substrate cleaning means disposed between the substrates and capable of cleaning the substrate, and a control device capable of controlling at least the operation timing of both processing heads and the substrate rotation means. Magnetic disk manufacturing equipment equipped with 9. A plurality of magnetic disks are mounted at predetermined intervals on the same rotating shaft, and a head slider with a magnetic head mounted on at least one surface of each of these disks is mounted at a predetermined position when the disk is at rest and in the initial state of rotation. In a magnetic disk drive equipped with a head drive device that elastically contacts and slides under pressure, floats due to high-speed rotation of the disk, and records and reads information using a CSS drive method that reciprocates in the radial direction of the disk. , the surface texture of the sliding surface of the magnetic disk in the relationship between the magnetic disk and the head slider that slides and floats on the disk is a surface texture that mimics the surface condition of a textured layer on the surface of a magnetic disk substrate made of a non-magnetic substrate. The surface of this disk substrate has convex portions with a substantially smooth surface, and in a three-dimensional load curve representing the surface shape, the amount of top deformation caused by the head load during CSS from the top of the surface The load ratio at a cut surface of considerable depth is 0.1 to 1.
A magnetic disk device comprising a non-magnetic substrate of 0%. 10. The surface of the disk substrate has a height of several n.
In the three-dimensional load curve representing the surface shape, the surface has a smoothed convex portion of m to several tens of nanometers,
10. The magnetic disk device according to claim 9, comprising a nonmagnetic substrate having a load ratio of 0.1 to 10% in a cross section at a depth of 5 nm from the top of the surface of the convex portion. 11. The magnetic disk drive according to claim 9 or 10, wherein the three-dimensional load curve as the property of the surface of the disk substrate has a flat shape at the extreme surface. 12. The surface properties of the disk substrate include microscopic concave grooves with a depth of at least 100 nm within the width of the head slider sliding surface, and Rsk≦-0 that displays symmetry of the cross-sectional curve.
．． 11. The magnetic disk device according to claim 9, comprising: 7. 13. The contact area between the head slider and the disk surface is S
, the initial state of the head slider on the disk sliding surface is σ≧ 13. The magnetic disk drive according to claim 9, comprising a disk sliding surface that comes into contact to maintain a W/S relationship.