JP2681299B2 - Recording medium substrate texture processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] An apparatus for performing texture processing on a non-magnetic substrate for manufacturing a thin film magnetic recording medium, wherein the texture processing conditions can be freely set from the inner peripheral side to the outer peripheral side of the substrate. In order to realize a texture processing device capable of performing the above, a polishing roller is pressed against the surface of a non-magnetic substrate by a pressure roller, and the substrate is rotated to perform texture processing. The hollow elastic body is filled with air to give elasticity, and a tread pattern is provided on the surface of the hollow elastic body.

[Industrial applications]

A magnetic recording medium, which is a recording medium in a magnetic disk device, has a coating film type in which a magnetic coating is applied to a non-magnetic disk, and a magnetic metal such as Co-Ni, Co-Pt, or iron oxide is formed into a film. There is a thin film type. The present invention relates to an apparatus for texturing a non-magnetic substrate for producing the latter thin film type magnetic recording medium.

[Texture processing]

FIG. 5 is a sectional view showing the whole of a conventional thin film magnetic recording medium. Reference numeral 1 denotes a substrate (disk) made of a non-magnetic material such as aluminum, on which a base layer 2, a magnetic film 3 and a protective film 4 are laminated in this order.

FIG. 6 is a view showing a sectional structure of a conventional thin film magnetic recording medium, in which the magnetic film 3 is formed of iron oxide (γ-Fe ₂ O ₃ ). The substrate 1 is made of aluminum, and the surface thereof is oxidized to form an alumite (Al ₂ O ₃ ) layer, which is used as the underlayer 2. The magnetic film 3 is formed by a γ-Fe ₂ O ₃ sputtering method. The protective film 4 is made of carbon or SiO _2.
Is formed by sputtering.

As the magnetic film 3, in addition to iron oxide (γ-Fe ₂ O ₃ ), C
oNi, CoNiCr, etc. are used.

In order to form this magnetic film 3, the method shown in FIGS. 7 to 9 is adopted. FIG. 7 shows a method called “stationary facing type”, in which ring-shaped targets 51 and 52 are arranged on both sides of the substrate 1, and the centers of the substrate 1 and the ring-shaped targets 51 and 52 are aligned. Therefore, since the substrate 1 is sputtered from the center in the radial direction under the same condition, the magnetic characteristics of the magnetic film are uniform over the entire circumference in the circumferential direction, and the recording / reproducing of information is accurately performed.

FIG. 8 shows a stationary type in which the substrate is rotated, and targets 61 and 62 are provided on both sides of the substrate 1. In this method, since the targets 61 and 62 are not point-symmetric with respect to the center of the substrate 1, uniform magnetic characteristics cannot be obtained in the circumferential direction of the substrate 1. Therefore, by rotating the substrate 1, the deposition conditions are made uniform and the magnetic characteristics are made uniform. However, dust may be generated from a sliding portion that rotatably supports the substrate 1, which may cause a defect, which is not practical.

FIG. 9 shows a method in which a large number of substrates 1 are simultaneously sputtered, which is called a passage type or in-line type. Reference numeral 7 denotes a support plate into which the substrates 1 ... Are inserted and supported in respective circular holes. And the support plate 7 is the target 61, 62.
Move between. This method can sputter magnetic films on a large number of substrates at the same time, but in each substrate 1, ... Sputtering is not performed under the condition of point symmetry with respect to the center of the substrates, so that the magnetic characteristics in the circumferential direction are It is not uniform and hinders the recording / reproduction of information.

FIG. 10 is a diagram showing a deposition pattern in this passage type sputtering method, (a) is a plan view and (b) is a side view of a substrate. Since molecules are scattered in all directions from the targets 61 and 62, when the substrate 1 passes between the targets 61 and 62, at the first time when the substrate 1 enters between the targets 61 and 62, the arrow a1 As shown by, the molecules come onto the substrate 1 from an oblique direction and are deposited. That is, as shown in (b), in the regions 1a and 1b before and after the substrate 1, molecules fly radially to the substrate 1 and are attached thereto.

However, in the upper and lower regions 1c and 1d of the substrate 1, molecules fly in the circumferential direction with respect to the substrate 1 and are attached thereto. As described above, since the deposition conditions change on the substrate 1 approximately every 90 degrees, there is a problem that the magnetic characteristics change in the circumferential direction of the substrate 1.

Therefore, it is called a texture, and before the formation of the underlayer 2 of the substrate 1, fine scratches in the circumferential direction are formed on the surface of the substrate 1,
By forming the underlayer 2 and the magnetic film 3 on it, the magnetic characteristics are improved. Note that the underlayer 2 can also be textured. By performing the texture treatment in this way, the easy axis of magnetization of the magnetic substance in the magnetic film is oriented in the texture direction, the magnetic characteristics due to the shape anisotropy increase, and the contact area between the medium surface and the magnetic head decreases. It becomes possible to improve the lubricity and prevent adsorption.

[Conventional technology]

FIG. 11 is a perspective view showing a conventional texture processing device. 1 is a mirror-finished substrate, 200 to 300 rpm
While the abrasive 8 and the cooling / lubricant are being supplied by the nozzle 8 onto the substrate 1 rotated by, the polishing tape 9 is pressed to scratch the surface of the substrate 1 in the circumferential direction. At this time, as the polishing tape 9, a tape to which a hard powder such as alumina is adhered is used, or a combination with some polishing agents is used.

The polishing tape 9 is fed from the feeding roll 10, and the guide roll 11, the pressure roller 12, and the guide roll 1 are fed.
3. By being wound by the winding roll 16 via the capstan 14 and the pinch roller 15, a new surface is constantly supplied to the substrate 1 side.

After performing the texture processing in this way, FIG.
The underlayer 2, magnetic film 3 and protective film 4 shown in FIG. 6 are formed. At this time, even if the film thicknesses of both the underlayer 2 and the magnetic film 3 are combined, it is as thin as about 2000 to 3000Å, so the magnetic film 3 becomes a thin uneven film along the unevenness due to the texture treatment, and the orientation of the magnetic substance is performed. Be done.

With such a conventional texture processing device, both with an abrasive tape and with free abrasive grains,
As the roller 12 for pressing the tape to the processed surface, a rubber roller 18 having a hardness of 40 to 50 degrees is lined on the metal roller 18 as shown in FIG. 12, and the pressure balance control mechanism shown in FIG. 13 is used. The polishing tape 9 is pressure-bonded to the processed surface.

In FIG. 13, the frame 20 supporting the support shaft 19 of the pressure roller 12 is supported by the device body 26 so as to be rotatable around the pressure balance center shaft 21. And the frame
An inner end 20i of 20 is supported by the texture device main body 26 via an inner pressure adjusting micrometer head 23i having an inner load cell 22 at the tip, and an outer end 20o of the frame 20 has an actor load cell 24 at the tip. It is supported by the texture device main body 26 via the outer pressure adjusting micrometer head 23o. Then, when the pressure roller 12 is pressed against the substrate surface from above the polishing tape 9 while the non-magnetic substrate 1 is rotated by the spindle 27, fine scratches in the circumferential direction are formed on the substrate surface, and texture processing is performed.

With this pressure balance adjusting mechanism, the display pressures of the load cells 22 and 24 and the substrate 1 are fixed, and the polishing tape 9 is run and pressed by the pressure roller 12, as shown in FIG.
A footprint 28 is formed on the substrate 1. Adjust the pressure springs 25i and 25o with both micrometer heads 23i and 23o to adjust the values of the load cells 22 and 24 in various ways to obtain the optimum footprint for the shape and dimensions of the inner and outer circumferences and the surface roughness. After being formed, texture processing is performed by adjusting the pressure balance with the load cells 22 and 24 so that a pattern equivalent to this footprint will be formed thereafter.

[Problems to be solved by the invention]

However, such a control mechanism has a limit in control, and especially for a large-diameter substrate, since the peripheral speed during processing is different between the inner peripheral side and the outer peripheral side, it is necessary to process all in-plane under uniform conditions. Is difficult. Further, the surface of the pressure roller 12 is susceptible to variations such as sesame hardness, surface accuracy, and quality of processed tape. Further, the dynamic pressing force is also easily affected by the accuracy, rigidity, vibration, etc. of the control device.

A technical object of the present invention is to solve such a problem and to realize a texture processing apparatus capable of freely setting conditions of texture processing from the inner peripheral side to the outer peripheral side of a substrate.

[Means for solving the problem]

FIG. 1 is a sectional view for explaining the basic principle of a texture processing apparatus for a magnetic recording medium substrate according to the present invention. Reference numeral 29 denotes a hollow rubber roller, that is, a roller made of a hollow elastic body in which air is enclosed so as to give elasticity by air pressure, and is supported by the support frame 20 via a support shaft 30 provided at the center. . The support frame 20 has an arrow W ₁ ,
As indicated by W ₂ , it is pressed against the substrate 1 side. Then, at the time of texturing, the polishing tape 9 is arranged between the substrate 1 and the hollow rubber roller 29, the hollow rubber roller 29 presses the polishing tape 9 against the surface of the substrate 1, and the substrate 1 is rotated and the polishing tape 9 is rotated. 9 is transferred.

[Action]

In this way, the hollow rubber roller 29 presses the polishing tape 9 against the surface of the substrate that is rotating, and the polishing tape 9 is transferred,
Since the texture is processed by rotating the hollow rubber roller 29, the polishing tape 9 is uniformly elastically pressed onto the substrate surface over the entire width thereof by the elasticity of the air pressure in the hollow rubber roller 29. Therefore, unlike the conventional apparatus, the entire surface can be uniformly textured without being affected by the variations in the rubber hardness and the surface accuracy of the surface of the pressure roller 12. Also, due to the elasticity of the air inside the hollow rubber roller 29,
The effects of precision, rigidity, vibration, etc. of the pressure balance control device are also absorbed and mitigated.

Internal and external pressure applied to the support frame 20
By adjusting W ₁ and W ₂ and the internal pressure in the hollow rubber roller 29 to control the processing surface and the tape bonding area, the footprint can be freely selected and the optimum processing conditions can be obtained over the entire surface.

Furthermore, by providing the tread pattern 31 on the surface of the hollow rubber roller 29, the polishing tape 9 is reliably pressed against the substrate surface at the edge of the tread pattern 31, and the texture processing is performed in a short time. By selecting the arrangement, angle, pitch, etc. of the tread pattern 31, the texture processing area and conditions can be set freely.

〔Example〕

Next, practical examples of how the apparatus for texturing a recording medium substrate according to the present invention is embodied will be described. FIG. 2 is a sectional view showing an embodiment of a pressure roller composed of a hollow rubber roller. 29a is a hollow rubber roller portion, which has the shape of an automobile tire. Then, the peripheral edges on both sides are connected to the metal hub portion 33 through the O-rings 32, 32 and other sealing members, the bearing housing 34 and the nut.
Installed at 35. The bearing housing 34 is provided with an air supply valve 36 having a check valve to supply compressed air into the hollow rubber roller portion 29a. In addition, a tread pattern 31 having, for example, a spiral shape is formed on the surface of the hollow rubber roller portion 29a.

The hollow rubber roller 29 is attached to the pressure balance control mechanism by inserting the support shaft 19 of the control mechanism in FIG. 13 into the hub portion 33. Then, by supplying compressed air into the hollow rubber roller portion 29a, while obtaining a desired air pressure, by setting the pressurizing forces W ₁ and W ₂ on both sides of the support shaft 21,
The desired texturing conditions can be obtained.

FIG. 3 shows various examples of footprints obtained by changing the texture processing conditions. (A) is an example in which the hollow rubber roller 29 of the present invention is used to perform texture processing while reducing the internal air pressure to a low value, and a wide footprint 37a is obtained over the entire surface. In addition, when the internal pressure of the hollow rubber roller 29 of the present invention is set to a low pressure and the outer peripheral side is strongly pressed for texture processing, a footprint as shown in (b) is obtained.
You get 37b. When the inner pressure is made high and the outer peripheral side is strongly pressed, the footprint in which the middle bulges as shown in (c)
You get 37c. When the inner pressure of the hollow rubber roller 29 is made high and the inner and outer pressures are uniformly applied, a thin footprint 37d as shown in (d) is obtained.

The footprints (a) to (c) can be easily obtained by making the rubber material of the hollow rubber roller 29 soft, and when the rubber material is hard, a thin footprint as shown in (d). 37d.

As described above, various footprints can be obtained depending on the internal pressure of the hollow rubber roller 29, the pressure applied inside and outside, or the rubber quality of the hollow rubber roller 29, and the texture processing conditions can be freely selected.

In the conventional texture processing with a pressure roller, especially when processing a large-diameter substrate, the surface roughness Ra: 20
A variation of up to 30 Å occurs, but when processed with the hollow rubber roller 29 of the present invention, the variation could be less than half. Further, due to the improvement of the processing speed, the processing time is shortened and the occurrence rate of scratches during processing is reduced.

FIG. 4 shows various embodiments of the tread pattern 31.
(A) is an example in which a slanted tread pattern is uniformly formed on the entire surface of the hollow rubber roller 29, which is suitable when texture processing is performed on the entire surface of the substrate under uniform conditions.

Further, as shown in (b), by forming a large number of tread patterns on the inner peripheral side of the hollow rubber roller 29 and reducing the outer peripheral side thereof, it is possible to perform texture processing mainly on the inner peripheral side of the substrate.

As shown in (c), at a specific place, over a predetermined width,
If the number of tread patterns is increased and the tread patterns are made denser, the texture processing can be intensively performed only in that area. Therefore, it is suitable for the case where only the CSS zone is textured intensively.

In this way, by providing the tread pattern 31 on the surface of the hollow rubber roller 29 and selecting the arrangement, pitch, angle of the tread pattern 31, hardness and material of the hollow rubber roller 29, internal pressure, etc., the conventional footprint shown in FIG. Unlike 28, you can freely select the footprint shape.

In the present invention, the polishing tape 9 is one in which an abrasive is attached to the polishing tape itself, or a tape polishing texturer that rubs the tape while supplying loose abrasive grains, such as a tape that is pressed by a pressure roller. Are all included.

In the figure, the hollow rubber roller 29 has a pressurizing portion and a hollow body integrated with each other.However, like a tire in an automobile, a rubber body having a tread pattern in which a confidential tube is arranged is used. Good.

〔The invention's effect〕

As described above, according to the present invention, with a processing roller formed of a hollow elastic body in which air is enclosed so as to give elasticity by air pressure, the polishing tape is pressed against the non-magnetic substrate,
Since the texture is processed by rotating the substrate, the elasticity of compressed air in the hollow elastic body can reduce the influence of the surface, hardness, surface precision, and polishing tape quality of the hollow elastic body. As a result, the polishing tape can be uniformly and stably pressed against the substrate surface. In addition, by selecting the hardness and internal pressure of the hollow elastic body, and the arrangement, pitch, and angle of the tread pattern formed on the surface of the hollow elastic body, you can freely select the footprint shape and set the texture processing conditions. .

[Brief description of the drawings]

1 is a sectional view for explaining the basic principle of a texture processing apparatus for a recording medium substrate according to the present invention, FIG. 2 is a sectional view for showing an embodiment of a hollow rubber roller according to the present invention, and FIG. 3 is an apparatus for the present invention. FIG. 4 is a diagram showing various obtained footprints, and FIG. 4 is a diagram showing an example of a tread pattern of a hollow rubber roller. FIG. 5 is a sectional view showing the whole of the thin film magnetic recording medium, FIG. 6 is a sectional view showing the layer structure of the thin film magnetic recording medium, and FIGS. 7 to 9 are perspective views showing various sputtering methods of the thin film magnetic recording medium. Fig. 10, Fig. 10 is a diagram showing a deposition pattern in a passage type sputtering method, Fig. 11 is a perspective view showing a conventional texture processing apparatus for a recording medium substrate, and Fig. 12 is a sectional view of a conventional pressure roller. FIG. 13 is a cross-sectional view showing a conventional pressure balance control mechanism, and FIG. 14 is a view showing a footprint by a conventional texture processing device. In the figure, 1 is a non-magnetic substrate, 9 is a polishing tape, 12 is a pressure roller, 29 is a hollow rubber roller, 29a is a hollow rubber roller portion, 30 is a spindle, 31 is a tread pattern, 28, 37a to 37d.
Indicate footprints, respectively.

Claims (2)

(57) [Claims] 1. An apparatus for performing texture processing by pressing a polishing tape (9) against the surface of a non-magnetic substrate (1) by a processing roller and rotating the substrate (1), wherein the processing roller is An apparatus for texturing a recording medium substrate, comprising a hollow elastic body (29) in which air is enclosed so as to give elasticity by air pressure. 2. An apparatus for performing texture processing by pressing a polishing tape (9) against the surface of a non-magnetic substrate (1) by a processing roller and rotating the substrate (1), wherein the processing roller is It is composed of a hollow elastic body (29) in which air is enclosed so as to give elasticity by air pressure, and a tread pattern (31) is formed on the surface of the hollow elastic body (29).
An apparatus for texturing a substrate for a recording medium, comprising: