JPS61222031A - Manufacture of magnetic disc - Google Patents

Abstract

PURPOSE:To manufacture a magnetic disc having a uniform output characteristic by turning a base while the center of a disc base is placed at a position with an offset by a prescribed amount from the center in the transverse direction of a sputter source on a moving axial line. CONSTITUTION:The sputter source has a long side Br larger than the outer size of disc base and a width Bx smaller than the outer size Do of the disc base. The width Bx of the sputter source is set smaller than the outer diameter of the disc base, the center of the disc base is subjected to a prescribed amount of offset toward the X direction from the center of the sputter source and sputtering is applied while turning the disc base. Thus, the film thickness is tilted and the magnetic disc with uniform output characteristic manufactured.

Description

[Detailed description of the invention] <m Required> Even when applying a magnetic film using the sputtering method, the thickness of the formed film is sloped in the middle between the inner diameter and the outer diameter, as is done with the spin code method, and the circumferential speed increases. To make it possible to compensate for the sensitivity caused by the difference.

Further, the degree of the above-mentioned inclination can be changed.

(Industrial Application Field) The present invention relates to a magnetic disk (recording medium) of a magnetic disk device.
In particular, the present invention relates to a method of manufacturing, by sputtering, a magnetic disk whose film thickness is varied in a radial direction in order to compensate for characteristics related to peripheral speed differences in the radial direction.

<Prior art> These magnetic disks have a magnetic recording film formed on a non-magnetic disc made of aluminum or the like, and write and read data using a magnetic head while rotating. Since the circumferential speed is different between the outside and the inside, the output is larger on the outer side and there is a problem that overwriting characteristics are poor2.
Uniformity has been achieved by reducing the film thickness on the outer peripheral side in accordance with the distance from the center of rotation.

This is due to the centrifugal force that increases as the radius increases each time a film-forming material is applied while rotating the disk substrate at high speed, commonly known as the spin code method, in the era when recording films were formed by painting. In order to balance the hardening time, the selection of mixed solvent and spindle rotation speed were varied to produce a recording film with controlled film thickness in the radial direction.

However, such a technique cannot be used because the film is deposited where the recording density is required to be even higher, and an appropriate method for controlling the film thickness in a radial direction has been required.

<Problems with the prior art> Film formation by vapor deposition or sputtering is basically a uniform film, and it is difficult to control the distribution so that it has a gradient in the radial direction. If you try to do this, there will be non-uniformity in the circumferential direction as well. On the other hand, in order to basically establish a system in which one head can access tracks from the inside to the outside, the output level must be corrected using other methods, such as interlocking control such as track monitoring and gain correction. It's not very interesting because it's added.

Solution> In view of the above, the purpose of the present application is to provide a method for manufacturing a magnetic disk in which the radial film thickness distribution can be controlled even in the sputtering method.

Therefore, in this application, the necessary sputtering equipment has a long side BY that is larger than the outer shape of the target disk substrate,
If you specify a sputtering source (the source of the film forming material) with a width Bx smaller than the outer diameter DO of the disk substrate and a position parallel to the sputtering source and a predetermined distance away (on a parallel plane), it should be approximately parallel to the width direction. It holds the disk substrate on the movement axis where the center of the long side and the center of the disk substrate almost coincide, and has a means for moving and stopping the disk substrate, a means for rotating around the center of the disk substrate, and a function for performing sputtering and stopping. , are necessary at least, but based on these assumptions, in this application, sputtering is performed by selecting a position on the axis of movement and rotating it (monitoring the film thickness if necessary) to obtain a predetermined thickness distribution. By the way, this is an attempt to solve the problem by terminating the problem.

Effect〉 If the above process is carried out using the above means, firstly, by rotating the disk substrate, the film thickness distribution in the circumferential direction can be made uniform, and secondly, the film thickness distribution from the span to the outside can be made uniform. Thirdly, the width B of the sputtering source should be the maximum.
As x becomes smaller (Bx/Do becomes smaller) compared to the outer diameter DO of the target disk substrate, the above maximum slope becomes thicker (
Fourthly, by increasing the offset 8, the distribution can be changed in the direction of decreasing the slope of the film thickness.If these factors are combined as factors in selecting the conditions, it is possible to change the distribution in the direction of decreasing the slope of the film thickness by increasing the offset 8. Sputtered films can be formed that have various radial inclinations with respect to the substrate and a uniform distribution in the circumferential direction.

(Effects) By combining the sputtered material with a specific magnetic head used in the target device and performing sputtering under conditions that provide a magnetic disk with uniform output characteristics (film thickness gradient), it is possible to It is possible to easily and reproducibly manufacture magnetic disks, and the versatility of the manufacturing equipment can also be maintained.

(Example) FIG. 1 is a basic explanatory diagram of the present invention, and FIG. 2 is a supplementary diagram of FIG. 1, showing the relationship between the sputtering source 1 and the disk 2 as seen from the The relative positional relationship and dimensions will be explained using a coordinate system in which directions are defined by orthogonal XYZ axes.

and 0) of the sputtering source 1 under the above definition. The center of the moving stage holding the disk 2, that is, the center Od or Odδ of the held disk 2
is 0dx= (X, O, O) and Odδ=(Xs−δ,
O, O), and the disk 2 is configured to be rotatable around Odδ or Odx, and it can be stopped at a selected position on the stage 3, and Zs can be changed and sputtering can be performed. is also configured to be possible.

Then, the disk 2 is rotated and sputtered at selected positions Zs and δ in the middle of the stage, and in the radial direction definition of the disk 2, Ri () corresponds to the innermost side of the rack) and Ro () corresponds to the outermost side of the rack. ), for example, if the layer thickness is expressed with a T suffix, TgJ>Tw, and for example, looking at the characteristics with the magnetic disk head and the ratio of Ro/Ri, the output characteristics will be uniform Tc / TQD = 1 .5-1.8
Select the conditions that achieve a predetermined film thickness ratio within the TQ
A desired magnetic disk medium is manufactured by forming a magnetic recording film (or a similar film) by sputtering to a thickness of about D=5×10 to 20×10 m.

FIG. 3 and subsequent figures are for explaining the characteristics of the movement of each parameter that governs the conditions when selecting the conditions in this way, and FIG. 3 is related to the parameter ZS.

As shown in Figures 3 and 5, as ZS increases, under other conditions being the same, the amount of adhesion spreads and tends to become somewhat lower, and the ratio between TQo and Tu becomes smaller and the peak becomes gentler. Although there is a tendency, as shown in Fig. 5, if it is increased too much, the adhesion rate will suddenly decrease, so it cannot be changed too much as a parameter.

Also, Fig. 4 shows the width Bx of the evaporation source (although it is called Bxe, there is not much difference from the above) and the sputter outer diameter D of the disk.
This is a graph summarizing the experimental results of TQ/Tao using the O ratio as a parameter. As Bx/DO becomes smaller, Ta/Too becomes smaller and the slope of the film thickness distribution in the radial direction becomes steeper. I understand.

Figure 6 is a graph summarizing experimental examples of the distribution of deposited film thickness using the offset amount δ as a parameter. It has both the tendency to move in the direction of the outer diameter rather than the position and the tendency to shift the value of T dai / T ψ to the smaller side, but T nail / Tw.

As a parameter that changes the value of B x / D o shown in Figure 4 above, it is sharper than B A magnetic disk having a desired inner and outer diameter film thickness (with uniform head detection sensitivity at both inner and outer diameters) can be manufactured using a sputtering device. Moreover, FIG. 7 summarizes the conditions that are made dimensionless by combining these to make it easier to find them.

In addition, since this method allows conditions to be adjusted within a predetermined range, it is possible to reproduce magnetic disks with different specifications using the same manufacturing equipment, and the film thickness can be adjusted according to the frequency characteristics of the head and head amplifier. You can also fine-tune the sensitivity balance by adjusting the ratio.

In this example, the relationship between dimensions DO/By in the Y direction is explained in two dimensions as 13y>>Do, but B
If y≧Do, then the slope of the mountain in Figure 4 will become a little steeper, but if you do the same thing, experiment and redefine the data for the percussion, the reproduction conditions will be satisfied and it can be put to practical use.

As explained above, according to the present invention, the dominant parameter δ
By selecting B This has the effect of making it easier to compensate for the difference in sensitivity when accessing with the film thickness, even in sputter disks, so the sputter disk has excellent resolution with no change in gain depending on access and uniformity in the radial direction. This has the effect that the device can be provided efficiently (and at low cost).

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment that also serves as the basic configuration of the present invention,
Figure 2 is a supplementary diagram of Figure 1, and Figures 3, 4, 5, 6, and 7 are supplementary explanatory diagrams of one embodiment of the present invention, and are radial distribution of film thickness during sputtering. An explanatory diagram regarding perturbation parameters governing the . Further, in the figure, 1 indicates a sputtering source, 2 indicates a disk, and 3 indicates a moving stage. 'l- Figure 3 Figure 2 Figure R (ant) Figure 4. Ta zs Kaya5I215me/lya

Claims (1)

[Claims] A sputtering source having a band-like width Bx and a sputtering source having a width Bx,
The magnetic disk has a means for holding the disk substrate at a predetermined distance apart in the direction and the Z direction, moving it in the In the method for manufacturing a disk, the width Bx of the sputtering source is set smaller than the outer diameter of the disk substrate, and the center of the disk substrate is offset from the center of the width of the sputtering source by a predetermined amount in the X direction. A method of manufacturing a magnetic disk, characterized in that sputtering is performed while rotating the disk substrate.