JPH05303740A - Substrate for magnetic disk and its production and magnetic disk formed by using the substrate - Google Patents

Abstract

PURPOSE:To provide the magnetic disk which can stably fly at a head lower than the conventional magnetic disks and has good attraction characteristics and CSS characteristics and is, therefore highly reliable. CONSTITUTION:This magnetic disk is constituted by successively forming a ground surface film, a magnetic film and a protective film on a substrate 1. Line trace patterns having 30 to 100Angstrom center line averaged roughness Ra, ruggedness of <300Angstrom max. projection height Rp and 5 to 30 deg. cross angle in a CSS zone 2 are formed on the surface of the ground surface film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk substrate, a method of manufacturing the same, and a magnetic disk using the substrate.

[0002]

2. Description of the Related Art The surface condition of a magnetic disk is determined by a texture process applied to a substrate before forming a magnetic film. The texture processing is a mechanical processing that is performed to give extremely fine irregularities to the surface of the base film after performing a mirror surface (polishing) process on the base film provided on the surface of the substrate. In recent years, as the density of magnetic disk devices has increased,
The flying height of the magnetic head mounted on the magnetic disk device is becoming smaller. In order to deal with such a situation, the surface of the magnetic disk substrate must be extremely smooth, and in the above-mentioned texture processing, multi-step finish processing is performed. The streak pattern formed by the above-described texture processing is usually a circumferential pattern, and the surface roughness Ra of the processed substrate is 50-14.
0Å is common.

Further, in order to avoid the above-mentioned multi-step texture, a method of imparting the above-mentioned unevenness by means other than the texture processing is also known. For example, a method using chemical etching (JP-A-62-239425, JP-A-1-307921), a method using sputter etching (JP-A-62-234237, JP-A-1-201825). ) Etc. have been proposed.

[0004]

However, since the method by the texture processing is mechanical processing, processing defects such as burrs and burrs remain even if the finishing processing is performed, and the finished substrate is too finished. There is a drawback that the surface roughness itself becomes too small. When the processing defect remains, it hinders stable flight of the head when the magnetic disk device is driven, or a head crash (HC) occurs at a contact start stop (CSS) when the magnetic disk device is started or stopped. .) Easily occurs. Also, if the surface roughness of the processed substrate itself becomes too small, the adsorption characteristics will be poor, and the problem that the head and disk will stick to each other and become immobile when the magnetic disk device is stopped is likely to occur. In particular, when the streak pattern formed by the texturing is a circumferential pattern, adsorption between the head and the disk is likely to occur. As described above, it is not easy to perform texture processing without leaving burrs and burrs and not overfinishing, and it is very difficult to balance the finishing degree in the current process control of texture processing. With that, it is almost impossible.

On the other hand, it is difficult to form appropriate irregularities by the method using chemical etching or sputter etching.
For example, in the case of a nickel-base aluminum substrate, the unevenness formed by chemical etching is nickel pitting, and the holes reach the aluminum of the substrate through the nickel layer. In this case, the magnetic characteristics of the magnetic layer are severely deteriorated and it cannot be used as a magnetic disk. When unevenness is formed by sputter etching, the above-mentioned pitching does not occur, but it takes a long time for etching, and it is difficult to control the potential distribution in the sputter chamber. There are productivity issues. Further, in the case of unevenness only by the above-mentioned etching treatment, the shape anisotropy of the magnetic characteristics due to the texture processing does not appear, so that the magnetic characteristics and the electromagnetic conversion are higher than those of the magnetic disk using the texture-processed substrate. Poor characteristics and poor performance as a magnetic disk.

The present invention has been made in view of the above circumstances, and an object thereof is to use a magnetic disk substrate excellent in flight stability of a magnetic head, CSS characteristics, and adsorption characteristics, a method for manufacturing the same, and the above-mentioned substrate. To provide a magnetic disk.

[0007]

That is, the present invention relates to a magnetic disk substrate, a method for manufacturing the same, and a magnetic disk using the substrate, and the gist of each invention is as follows. The first gist is a substrate made of a non-magnetic material on which an underlayer film is formed, and the centerline average roughness R on the surface of the underlayer film.
a is 30 to 100Å and the maximum protrusion height Rp is 300Å
And the cross angle in the CSS zone is 5 to 3
A magnetic disk substrate is characterized by being formed with a 0 ° streak pattern. The second point is that after applying a base film on a substrate made of a non-magnetic material, a texture process is applied to form unevenness and a CSS zone having a center line average roughness Ra of 30 to 100Å and a maximum protrusion height Rp of 150 to 600Å. A streak pattern having a cross angle of 5 to 30 ° is formed on the surface of the undercoating film, and then the surface of the undercoating film is subjected to a chemical etching treatment so that the maximum protrusion height is substantially unchanged without changing the center line average roughness Ra. A method for manufacturing a magnetic disk substrate is characterized in that Rp is less than 300Å. A third gist is a magnetic disk in which a base film, a magnetic film, and a protective film are sequentially formed on a substrate, the center line average roughness Ra of which is 30 to 100Å and the maximum protrusion is formed on the surface of the base film. The magnetic disk is characterized by being formed by forming unevenness having a height Rp of less than 300Å and a striation pattern having a cross angle of 5 to 30 ° in the CSS zone.

The present invention will be described in detail below. First, a magnetic disk substrate of the present invention and a method for manufacturing the same will be described. The magnetic disk substrate of the present invention is a substrate made of a non-magnetic material provided with an undercoating film, and the centerline average roughness Ra of the undercoating film is 30 to 100 Å and the maximum protrusion height Rp is less than 300 Å. It is formed by forming a streak pattern having an unevenness and a cross angle of 5 to 30 ° in the CSS zone.

According to the manufacturing method of the present invention, the above-mentioned magnetic disk substrate is formed by applying a base film on a substrate made of a non-magnetic material and then performing texture processing to obtain a center line average roughness Ra of 30 to 100 Å and a maximum protrusion. Height Rp is 150-60
The unevenness of 0Å and the cross angle in the CSS zone are 5 to 3
A 0 ° streak pattern is formed on the surface of the undercoating film, and then the surface of the undercoating film is subjected to a chemical etching treatment so that the maximum protrusion height R is substantially unchanged without changing the center line average roughness Ra.
It can be obtained by setting p to less than 300Å.

In the present invention, aluminum or an aluminum alloy represented by Al--Mg is used as the material of the nonmagnetic material substrate. Further, as the material of the base film, a metal or an alloy harder than the substrate is used, and a base film made of a Ni-P electroless plating film is typical. Usually, the thickness of the substrate is about 1 to 3 mm, and the thickness of the base film is about 20 to 30 μm. An underlayer film-formed substrate in which an underlayer film of a Ni-P electroless plating film is provided on the surface of an Al-Mg alloy substrate and the underlayer film is mirror-finished is commercially available as Subrate. In the present invention,
The above Substrate can be used as it is.

First, in the manufacturing method of the present invention, specific unevenness and streak patterns are formed on the surface of the base film by texture processing. The texture processing can be performed by a known method such as a method using a polishing pad or free abrasive grains, a method using a polishing tape, or the like. FIG. 1 is a plan explanatory view of an example of a polishing apparatus used for texture processing, and FIG. 2 is a partial sectional explanatory view of the polishing apparatus shown in FIG. FIG. 3 is an enlarged plan view of a main portion of the texture streak pattern. In the figure, (1) is a base film forming substrate, (2) is a CSS zone, (3) is a pressing member,
(4) represents a polishing pad, and (θ) represents a cross angle in the CSS zone.

The polishing tape is typically 250
As a polishing tape carrying alumina abrasive grains of about 0 to 6000 # and free abrasive grains, typically, "Polypla 700" and "Polypla 103" manufactured by Fuji Incorporated Co., Ltd. Slurries) and polishing pads are typically manufactured by Fuji Incorporated "Surfin 100" and "Surfi".
n ΧΧΧ-5 ".

In the above texturing, the center line average roughness Ra is 30 to 100Å and the maximum protrusion height R is
An uneven pattern having p of 150 to 600Å and a scratch pattern having a cross angle of 5 to 30 ° in the CSS zone are formed on the surface of the base film. The cross angle (θ) in the CSS zone
Means the angle at which the texture streaks intersect at the head shipping zone.

The above centerline average roughness Ra and maximum protrusion height Rp can be achieved by adjusting, for example, the dilution concentration of the slurry, the processing time, the pressurizing time, the rotation speed of the spindle, and the like. Maximum protrusion height Rp is 150-60
The state of 0 Å occurs due to burrs and burrs that are inevitably formed when the state where the center line average roughness Ra is 30 to 100 Å is not formed. Burrs and burrs are small protrusions on the average surface. The center line average roughness R
The a and the maximum protrusion height Rp can be evaluated by measuring with a surface roughness meter (“Taristep” manufactured by Rank Taylor Hobson Co., Ltd.) having a tip with a 0.2 μm square tip at a measurement length of 250 μm.

On the other hand, the above-mentioned striation of the cross pattern can be achieved by adjusting the disk rotation speed and the polishing pad pressing rotation speed to an appropriate ratio. The streak pattern in texture processing is usually
Although it is a circular pattern, in the present invention, the adsorption characteristic can be improved by forming the cross pattern in which the cross angle in the CSS zone is 5 to 30 °. And a preferable cross angle is 10 to 25 °.

Next, in the manufacturing method of the present invention, the surface of the base film is subjected to chemical etching treatment. The chemical etching treatment can be performed by immersing the textured substrate in an etching solution. As the etching liquid, sulfuric acid, nitric acid, a fluorine compound solution or the like is used.

Burrs and burrs generated by the texturing process have a large specific surface area and are active, so that they are dissolved in the etching solution before the surrounding portions. As a result, by the etching process, the state of the surface of the base film is such that burrs and burrs are selectively removed, and the maximum protrusion height Rp can be made less than 300Å without substantially changing the center line average roughness Ra. I can. And, the pitching that occurs in the conventional technique does not occur.

Appropriate processing temperature and processing time are selected as conditions for the etching processing depending on the kind of the etching solution. For example, when an aqueous solution of sulfuric acid having a concentration of 2 to 40% by volume is used, treatment conditions of 20 to 60 ° C. and 1 to 60 minutes are suitable. Then, the textured substrate is pulled out of the etching solution when burr and burrs are dissolved, and is washed under appropriate conditions.

The surface state of the magnetic disk substrate of the present invention has a center line average roughness Ra of 30 to 100 Å and a maximum protrusion height Rp of less than 300 Å, preferably 200 to 25.
It is 0Å. Such surface condition is stable flying of the head and C
It greatly contributes to the improvement of SS characteristics.

4 to 7 are explanatory views showing the results of Examples and Comparative Examples described later. FIG. 4 is an explanatory diagram showing the surface state of the base film forming substrate, where the horizontal axis represents the center line average roughness R.
a, the vertical axis represents the maximum protrusion Rp. In the figure, □ is a textured one-step processed product, △ is a one-step processed product with a finish textured two-step processed product, and ○ is a one-step processed product subjected to a chemical etching treatment. is there. In each mark, a white mark represents a line pattern product with a circumferential pattern, and a black mark represents a line pattern product with a cross pattern.

FIG. 5 is an explanatory diagram showing the coefficient of static friction of each magnetic disk obtained from the three types of processed substrates shown in FIG. 4 in distinction for each line pattern of texture processing.
The vertical axis represents the coefficient of static friction. FIG. 6 is an explanatory diagram showing the friction coefficient of each magnetic disk after CSS 20,000 times obtained from the three types of processed substrates shown in FIG. Represents a coefficient. Further, “HC” in FIG. 6 means head crash. FIG. 7 is an explanatory diagram showing the stable flight height of the head for each magnetic disk obtained from the three types of processed substrates shown in FIG. 4 by distinguishing for each stripe pattern of texture processing, and the vertical axis represents the head. It represents the stable flight height (μm).

As shown in FIG. 4, when the texture one-step processed product and the two-step processed product are compared, the two-step processed product has a small Rp due to the finish texture, and therefore the minute protrusions are small. At the same time, Ra is also small. On the other hand, in the etched product, Ra does not change and only Rp is small.

The above results show that the surface itself is smoothed in the textured two-step processed product and the fine projections are reduced, whereas the surface itself is not smoothed in the etched product, but only the fine projections are produced. It shows that it is decreasing. That is, it indicates that the fine protrusions generated in the one-step textured product were selectively removed by the chemical etching treatment.

As is apparent from FIG. 5, the textured two-step processed product having the surface itself smoothed has a static friction coefficient of about 0.4 to 0.5, and the textured one-step processed product,
It can be seen that it is higher than the etching-treated product and is very easily adsorbed. In the comparison between the circumferential pattern streak product and the cross pattern streak product, there is almost no difference between the texture one-step processed product and the texture two-step processed product and the etching processed product. The static friction coefficient of all the traces is small. In the textured one-step processed product, the actual contact area with the head is extremely small because the minute protrusions are not removed in both the circumferential pattern product and the cross pattern product, and the difference in static friction coefficient is observed. I can't. In the textured two-step processed product and the etched product, since the fine protrusions are reduced or removed, the actual contact area with the head in the cross pattern striation product is smaller than that in the circumferential pattern striation product. , The coefficient of static friction becomes smaller.

The following can be seen from FIG. That is, the one-step textured product (A) is likely to cause a head crash and has a high friction coefficient. This is because a large number of minute protrusions generated by the texture processing are worn by sliding with the head. In the two-step textured product, no head crash is observed, but adsorption is likely to occur and the friction coefficient is high. A comparison between the circumferential pattern striations and the cross pattern striations shows that the latter is somewhat difficult to adsorb and the friction coefficient is low. The textured two-stage processed product is CSS
As a result, the surface is further smoothed, so that the true contact area between the head and the disk is increased and the adsorption tends to occur. In comparison between the circular pattern striations and the cross pattern striations, the true contact area between the head and the disk is more circular in the cross pattern striations even if the surface is smoothed by CSS. It is smaller than the scratched product of the pattern, and the friction coefficient after CSS is small. The etching treated product shows neither head crash nor adsorption tendency, and the friction coefficient after CSS 20,000 times is as low as about 0.4. This is because the fine projections that are the cause of the head crash are selectively removed by etching, and the surface itself is not smoothed. The difference between the circumferential pattern striations and the cross pattern striations is due to the same reason as described for the textured two-step processed product.

As shown in FIG. 7, the stable flight height of the textured one-step processed product is about 0.12 μm, which is about 0.05 μm compared with the stable flight height of the textured two-step processed product and the etched product. It is also high and is not suitable for a magnetic disk device for high density recording. In the case of the textured two-step processed product, the surface itself was smoothed, and in the case of the etching-processed product, only the minute projections were removed.
The stable flight height is around 0.07 μm, and the head can fly stably. Further, the difference between the circumferential pattern streak product and the cross pattern streak product is not recognized in any of the texture one-step processed product, the two-step processed product, and the etched product. This is because the heights of the micro-protrusions are almost the same in both the circumferentially patterned product and the cross pattern product.

As described above, the substrate having good head flight stability, adsorption property, and CSS property is only the etching-processed product, and the one-step textured product is the CS-processed product.
The flight stability of S and the head is poor, and the two-step textured product has poor adsorption properties and CSS properties. Further, there is almost no difference in flight stability of the head between the circumferential pattern striations and the cross pattern striations,
The latter is good in terms of adsorption characteristics and CSS characteristics.

Next, the magnetic disk of the present invention will be described. In the magnetic disk of the present invention, a magnetic film and a protective film are sequentially formed on a magnetic disk substrate provided with the above-mentioned undercoat film, and further, a lubricant is applied on the protective film, if necessary. can get. The formation of the magnetic film and the protective film can be performed according to a known process such as sputtering, plating and vapor deposition. As the magnetic film, CoCr, C
oNiCr, CoTaCr, CoPt, CoCrPt,
CoCrB, CoCrTaB, CoCrPtB, Co
P, CoNiP, CoZnP, CoNiZnP, CoN
A Co-based magnetic film such as iO or a Fe-based magnetic film such as ferrite and iron nitride can be used. The magnetic film may be either an in-plane magnetized film or a perpendicular magnetized film. As the protective film, C, SiO ₂ , ZrO ₂ or the like can be used. As the lubricant, a solid or liquid commercially available lubricant can be used.

[0029]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In addition, in the following examples, each measurement was performed by the following method. (1) Height of protrusion and uniformity of height of protrusion Measured in a radial direction for protrusions on arbitrary straight lines in the inner peripheral portion, the central portion, and the outer peripheral portion on the substrate, and the average value of the measured values is defined as the protrusion height. The width of the value was defined as the uniformity of the protrusion height.

(2) CSS characteristics Evaluation was carried out by using a CaTiO ₃ head slider with a weight of 9.5 g and measuring the friction coefficient after 20,000 CSS cycles. (3) Pass / Fail of Head Stick Evaluation was performed by leaving the head and the magnetic disk in a static contact state for 1 hour in an atmosphere having a temperature of 25 ° C. and a humidity of 80%, and measuring the friction coefficient at startup. (4) Stable flying height of head The height at which the head started to collide with one protrusion was defined as the stable flying height of the head, which was measured by a commercially available glide tester.

Example 1 Four commercially available Ni-P alloy-plated disk substrates were textured using polishing abrasives "Polypla 700" and polishing pad "Surfin 100" manufactured by Fuji Incorporated. The processing conditions are as follows: disk rotation speed: 125 rpm, polishing pad pressing rotation speed: 40 rpm, polishing pad pressing pressure: 10 ps
i, processing time: 20 seconds. The surface state of the textured substrate (corresponding to the black square in FIG. 4) is an average Ra:
70Å, average Rp: 425Å, average cross angle: 25 °
(Each value is an average value of four substrates. The same applies hereinafter.). Each of the above textured substrates has a concentration of 20
The plate was immersed in a volume% sulfuric acid aqueous solution at 25 ° C. for 30 minutes for etching treatment, and then washed with water and dried. Surface condition of etching-treated substrate (corresponding to black circle in Figure 4)
The average Ra was 68Å, the average Rp was 245Å, and the average cross angle was 25 °. The Cr base film (1000
Å), Co-Cr-Ta magnetic film (700 Å), C protective film (300 Å), cleaning treatment with 0.5 mm alumina tape, and further applying commercially available fluorocarbon lubricant to a thickness of 25 Å I made a magnetic disk. Table 1 shows the results of the performance tests of the obtained magnetic disks.

Comparative Example 1 In the same manner as in Example 1, four commercially available Ni-P alloy plated disk substrates were textured. The processing conditions were as follows: disk rotation speed: 125 rpm, polishing pad pressing rotation speed: 3 rpm, polishing pad pressing pressure: 20 psi, processing time: 20 seconds. The surface condition of the textured substrate (corresponding to the □ mark in FIG. 4) has an average Ra: 70Å, an average Rp: 400Å, an average cross angle:
It was 0 °. Concentration of each of the above textured substrates is 1
It was immersed in a 5% by volume aqueous solution of sulfuric acid at 40 ° C. for 15 minutes for etching, and then washed with water and dried. The surface condition of the etched substrate (corresponding to the circle in Fig. 4) is
The average Ra was 67Å, the average Rp was 240Å, and the average cross angle was 0 °. On the surface of each of the above-mentioned etching-treated substrates, a Cr underlayer and a Co—Cr— film were sequentially formed in the same manner as in Example 1.
After forming the Ta magnetic film and the C protective film, cleaning treatment was performed in the same manner as in Example 1, and then a commercially available fluorocarbon lubricant was applied to a thickness of 20Å to prepare a magnetic disk.
Table 1 shows the results of the performance tests of the obtained magnetic disks.

Comparative Example 2 The same as Example 1 except that the etching treatment was omitted, the second-stage texture processing was performed, and the coating thickness of the fluorocarbon lubricant was changed to 28 Å. Created a magnetic disk. The second step of the texture processing is polishing abrasive grains "Polypla 103" and polishing pad "Surfin 1" manufactured by Fuji Incorporated.
00 "was used, the disk rotation speed was 125 rpm, the polishing pad pressing rotation speed was 40 rpm, the polishing pad pressing pressure was 5 psi, and the processing time was 30 seconds. The surface state of the textured two-step processed substrate (corresponding to the black-painted Δ mark in FIG. 4) has an average Ra: 40Å and an average Rp:
235Å, average cross angle: 25 °. The results of the performance test of the obtained magnetic disk are shown in Table 1.

Comparative Example 3 Comparative Example 1 was carried out in the same manner as Comparative Example 1 except that the etching treatment was omitted, the second-stage texture processing was performed, and the coating thickness of the fluorocarbon lubricant was changed to 24 Å. Created a magnetic disk. The second texturing process was performed in the same manner as in Comparative Example 2. Regarding the surface state of the textured two-step processed substrate (corresponding to the mark Δ in FIG. 4), the surface state of the etching-treated substrate was Ra: 42Å, Rp: 240Å, and average cross angle: 0 °. Table 1 shows the results of the performance tests of the obtained magnetic disks.

[0035]

[Table 1] ──────────────────────────────────── After CSS 20,000 times 25 ℃, 80% R ． H. Stable head floating coefficient of friction Frictional coefficient after standing Upper height (μm) ──────────────────────────────────── -Example 1 0.33 0.16 0.065 0.36 0.16 0.067 0.38 0.18 0.071 0.32 0.17 0.072 ─────────── ───────────────────────── Comparative Example 1 0.81 0.24 0.073 0.71 0.28 0.066 0.76 0 .23 0.070 0.78 0.26 0.069 ───────────────────────────────────── Comparative Example 2 0.83 0.37 0.079 1.21 0.44 0.078 Adsorption after 10,000 times 0.41 0.073 0.95 0.42 0.074 ─────────── ───────── ───────────────── Comparative Example 3 1.41 0.51 0.080 Adsorption at 5000 times 0.46 0.072 Adsorption at 10,000 times 0.53 0.075 8000 0.48 0.078 ────────────────────────────────────

[0036]

As described above, according to the present invention, a magnetic head having a lower head and more stable flight than the conventional magnetic disk, good adsorption characteristics and CSS characteristics, and thus a highly reliable magnetic disk is provided. It

[Brief description of drawings]

FIG. 1 is an explanatory plan view of an example of a polishing apparatus used for texture processing.

FIG. 2 is a partial cross-sectional explanatory view of the polishing apparatus shown in FIG.

FIG. 3 is an enlarged plan view of a main portion of a texture streak pattern.

FIG. 4 is an explanatory diagram showing a surface state of a base film forming substrate, in which a horizontal axis represents a center line average roughness Ra and a vertical axis represents a maximum protrusion Rp. In the figure, □ indicates a textured one-step processed product, Δ mark a one-step processed product with a finish textured two-step processed product, and ○ mark an etching processed product obtained by subjecting the one-step processed product to a chemical etching treatment. In each mark, a white mark represents a line pattern product with a circumferential pattern, and a black mark represents a line pattern product with a cross pattern.

FIG. 5 is an explanatory diagram showing the static friction coefficient of each magnetic disk obtained from the three types of processed substrates shown in FIG. 4 separately for each line pattern of texture processing, and the vertical axis represents the static friction coefficient. ..

6 is an explanatory diagram showing the friction coefficient of each magnetic disk obtained from the three types of processed substrates shown in FIG. 4 after CSS 20,000 times, separately for each line pattern of texture processing;
The vertical axis represents the coefficient of friction.

FIG. 7 is an explanatory view showing the stable flying height of the head for each magnetic disk obtained from the three types of processed substrates shown in FIG. 4 by distinguishing for each scratch pattern of texture processing, and the vertical axis represents the head. It represents the stable flight height (μm).

[Explanation of symbols]

 1: Substrate 2: CSS zone 3: Pressing member 4: Polishing pad

Claims (3)

[Claims] 1. A substrate made of a non-magnetic material having an undercoating film, wherein the centerline average roughness Ra is 30 to 30 on the surface of the undercoating film.
A substrate for a magnetic disk, which is formed by forming irregularities having a maximum protrusion height Rp of less than 300Å and a striation pattern having a cross angle of 5 to 30 ° in the CSS zone. 2. A center line average roughness Ra of 30 to 100 Å and a maximum protrusion height Rp of 150 to 60 are formed by applying a base film on a substrate made of a non-magnetic material and then performing texture processing.
The unevenness of 0Å and the cross angle in the CSS zone are 5 to 3
A 0 ° streak pattern is formed on the surface of the undercoating film, and then the surface of the undercoating film is subjected to a chemical etching treatment so that the maximum protrusion height R is substantially unchanged without changing the center line average roughness Ra.
A method of manufacturing a substrate for a magnetic disk, wherein p is less than 300Å. 3. A magnetic disk comprising a substrate, a base film, a magnetic film and a protective film which are sequentially formed on the surface of the base film having a center line average roughness Ra of 30 to 100Å and a maximum protrusion height. A magnetic disk characterized by being formed by forming a concavo-convex pattern having a roughness Rp of less than 300Å and a streak pattern having a cross angle of 5 to 30 ° in the CSS zone.