JP2611976B2 - Method for manufacturing magneto-optical recording film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a magneto-optical device having a rare earth-transition metal amorphous ferrimagnetic alloy thin film (hereinafter abbreviated as RE-TM film) as a recording layer. The present invention can be used as a method for manufacturing a disk, and in particular, can be used to determine specifications of a magneto-optical disk manufacturing apparatus when a rare earth-transition metal alloy target (hereinafter abbreviated as RT target) is used.

(Prior Art) There has been active research on practical use of an erasable optical disc having an RE-TM film as a recording layer. The sputtering method is suitable as a method for producing the RE-TM film in terms of mass productivity, large area uniformity, low temperature processability, and the like. Conventionally, RE-TM film sputter formation typically involves sputtering a composite target in which a RE chip is placed on a TM disk, and simultaneously sputtering the RE target and the TM target while rotating the substrate. is there. Methods other than the above two methods for sputtering an RT target have not been used at the research and development level because a high quality alloy target has not been obtained so far. An RT target capable of obtaining a RE-TM perpendicular magnetization film has been developed, as disclosed in the Abstract of the Japan Society of Applied Magnetics, 28aA-9, P191, 1985.

However, when using the RT target, it should be noted that the RE-TM formed on the substrate surface may be used.
This is a problem of non-uniformity of film properties. This is because the RE element is non-magnetic and the TM element is ferromagnetic at the target temperature during sputtering even when an RT target having a uniform composition is used. This is a problem caused by the difference in distribution. Due to the limitations of the optical disk substrate material, low-temperature film-forming properties are required for the manufacture of optical disks, and from this point, magnetron sputtering is preferred among sputtering methods,
On the other hand, when the RT target is used as the magnetron sputtering source, the difference in the sputter emission angle distribution between the RE and the TM from the RT target surface is promoted by the effect of the TM sputter particles being restrained by the magnetron field. Therefore, it is particularly necessary to pay attention to the uniformity of the film characteristics described above. Due to the fact that a practical RT target has just been developed, the above considerations are still insufficient.

(Problems to be Solved by the Invention) The present invention is intended to solve the problem of non-uniformity of RE-TM film characteristics on a substrate surface when forming an RE-TM film using an RT target. It is assumed that.

[Configuration of the invention]

(Means for Solving the Problem) The present invention provides an R-T
The relative positional relationship between the target and the substrate is represented by the angle θ [deg] between the line segment OP connecting the RT target center point O and an arbitrary point P on the substrate surface and the substrate surface, and the length L of the OP. [Cm], and the substrate surface is set in an area of the defined position.

The area of the substrate position P defined by the present invention is 0 [cm] <L ≦ 11.25 [cm] and 0 [deg] <θ ≦ 90 [de
g] or 11.25 [cm] <L ≦ 33.75 [cm] and 4 [deg / c]
m] × L−45 [deg] ≦ θ ≦ 90 [deg].

(Operation) By applying the above-described means of the present invention, a perpendicular magnetization film can be obtained over the entire substrate surface even when an RT target is installed in a magnetron type sputtering source and a RE-TM film is formed. And rotated on the substrate in the region P.
Since a moving operation such as revolution is provided, a RE-TM film having a uniform film thickness distribution and magneto-optical characteristics can be obtained.

The effect of the present invention is particularly large when using a magnetron type sputtering source in which the sputter emission angle distribution of RE sputtered particles and TM sputtered particles from the RT target surface is particularly different. Even when a source is used, a very good uniformity film can be obtained by arranging the substrate at the position defined in the present invention.

Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a positional relationship between a target and a substrate in the method of manufacturing a magneto-optical recording film according to the present invention, and FIG. 2 is a configuration diagram of a sputtering device for accommodating the target and the substrate in the positional relationship shown in FIG. It is. 1 and 2, reference numeral 1 denotes a sputtering chamber, 2
Is a substrate holder, 3 is a holder support rod (can be arranged at three positions of 31, 32, and 33), 4 is a sample having a substrate of 5 mm Si, 5 is a TbCo alloy target (Tb28.2Co71.1O0.5C0. Atomic composition ratio of 2), 6 is an anode, 7 is a magnet for magnetron discharge, 8 is a magnet rotating rod, 9 is a sputter source case, 10 is an insulation shield, 11 is a DC power supply, 12 is a shutter, and 13 is a substrate elevator. And a case to store the rotator, 14 is Ar
A gas introduction system 15 is an exhaust system.

With the above configuration, the method of forming the magneto-optical recording film of the present invention was carried out by the following procedure, including comparison with the prior art. First, a Si chip 4 for evaluating magneto-optical characteristics was placed on the substrate holder 2 having the configuration shown in FIG. The arrangement was performed by changing the distance ^r s from the center of the substrate holder so that the target 5 was radially formed around the target center point O when the target 5 was viewed from the substrate holder side. The distance D between the center of the substrate holder and the center of the target is 13cm, 15c
m (position 31 in FIG. 2) (for D = 13 cm, a different sputter apparatus from that of FIG. 2 was used, but the basic configuration is the same as that of FIG. 2), and 7 cm (32 in FIG. 2). Position), 2
1 cm (at the position 33 in FIG. 2), the target-substrate holder spacing G is 7 cm and 11 cm for D = 13 cm, and 17 cm and 23 cm for D = 15 cm. Were changed as parameters. When D = 7 cm and 21 cm, G = 17 cm.

For the above six types of substrate arrangements, four types of TbCo film formation experiments were performed with the substrate holder stationary and three with the substrate rotating.
I did it. The TbCo film is formed by placing a Si chip on the substrate rudder 2 by the above-described arrangement method, exhausting the inside of the sputtering chamber 1 to 5 × 10 ⁻⁶ Torr by the exhaust system 14, and then supplying Ar gas from the gas introducing system 13. 75 sccm inflow, the exhaust system 14 was adjusted to adjust the gas pressure in the sputtering chamber to 5 mTorr, and then the magnet 8 was set to 6 rpm.
With the shutter 12 closed, power was applied to the target 5 from the DC power supply 11 to perform pre-sputtering for 10 minutes, and then the shutter 12 was opened.
The magneto-optical characteristics of the sample 4 on which the TbCo film was formed were measured using a Kerr hysteresis measuring device.

Fig. 3 shows the position (L, Q) of each sample and the TbC
FIG. 9 is a diagram showing whether the film has perpendicular magnetization or in-plane magnetization. When G, D, and r _s are used for L and θ, when the surface of sample 4 is parallel to the substrate holder surface, I can ask more. The locus A of the plot points in FIG. 3,
B, C and D are A (G = 23 cm, D = 15 cm), B (G = 17 cm, D
= 15 cm), C (G = 11 cm, D = 13 cm), D (G = 7 cm, D
= 13 cm) and E (G = 4 cm, D = 10 cm) showing the results of samples obtained with the substrate stationary. As is clear from FIG. 3, in the range of θ90 deg, 4 [deg / cm] × L
It is clear that the perpendicular magnetization film is in the region where θ is larger than -45 deg, and the in-plane magnetization film is in the region where θ is smaller than 4L-45.The TbCo film that can be used as the magneto-optical recording film is θ4L-4.
It turns out that it can be formed only in the area of 5. Also, θ90d
In the range of eg, P ₁ ′ and P ₂ ′ two plot points (each position is θ
(= 90 deg) is the result of tilting the surface of the sample 4 from the holder surface, and it can be seen that the magneto-optical characteristics are also symmetric with respect to θ = 90 deg for the same L. This can be sufficiently estimated from the positional relationship shown in FIG. 1, and the position of θ shown in FIG. 1 and the position of 180 ° −θ are completely equivalent. Since the position is uniquely determined within the range of 0 ° θ90 ° in any arrangement, the upper limit of θ90 ° is provided in the present invention.

 In the present invention, i) 0 <L ≦ 11.25 [cm] and 0 <θ ≦ 90 [deg] or ii) 11.25 [cm] <L ≦ 33.75 [cm] and 4 [deg / cm] × L-45 [deg] ] ≦ θ ≦ 90 [deg].

However, if G is too small, discharge may not be easily generated even in magnetron sputtering, and a problem such as an excessive heat load on the substrate may occur.
(30/20) L + 30 is desirable.

FIG. 4 plots the sample position on the substrate and the film coercive force in the direction perpendicular to the sample surface for a series of samples B in FIG. 3, and also shows the results of composition analysis by ICP emission spectroscopy. I have. From Figure 4, during the r _s = 7 cm from directly above the target of Co-rich Kerr loop, r _s = 6cm~0
up to cm, Tb-rich Kerr loops, r _s 3cm or more on the opposite side of the target from the in-plane magnetization film to Kerr loops, and the composition is certainly changing like that. I understand. The reason for this is considered to be the difference in the sputter emission angle distribution of the Tb particles and Co particles from the target surface. The inventors of the present invention obtained the results of FIG. 4, that is, the Co-rich region and the Tb-ri centered on rs = 7 cm (D = 15 cm, G = 17 cm).
Focusing on the fact that the channel region is almost symmetric, the distribution when the substrate holder is rotated with the center of the substrate holder set to D = 9 cm near this point was examined. As a result, as shown by 32 in FIG. 5, a very uniform TbCo film was obtained in the region where the coercive force was | r _s | 10 cm.

In FIG. 5, the case of D = 15 cm is indicated by 31, and the case of D = 21 cm is indicated by 33. The fact that the magneto-optical characteristics shift toward the Co-rich side as the distance to the outer periphery of the substrate holder increases at D = 15 cm can be easily estimated from the result of the stationary state shown in FIG.
On the inner side of the disc holder shown in the figure, the sample surface is
While passing through the Tb-rich region and the in-plane magnetization region while rotating alternately, on the outer side of the disk holder in FIG. 5,
This is because the sample surface passes through the Co-rich region and the in-plane magnetization region shown in FIG. 4 while rotating alternately.

At 32 in FIG. 5 where the substrate is arranged according to the invention, the Co-r
It passes through the ich vertical region and the Tb-rich vertical region alternately while rotating almost symmetrically, so that the characteristics are uniform.

〔The invention's effect〕

According to the method for producing a magneto-optical recording film of the present invention, when producing an RE-TM film by sputtering an RT alloy target, the film thickness distribution and magneto-optical characteristics are uniform and extremely uniform on the substrate surface. An RE-TM film with good properties can be manufactured.

[Brief description of the drawings]

FIG. 1 is a view showing the positional relationship between a target and a substrate, FIG. 2 is a view showing the configuration of an embodiment of a sputtering apparatus, and FIGS. 3 to 5 show the effects of the method for manufacturing a magneto-optical recording film of the present invention. FIG. DESCRIPTION OF SYMBOLS 1 ... Sputter chamber, 2 ... Substrate holder, 3 ... Holder support rod, 4 ... Sample, 5 ... Rare earth-transition metal alloy target, 6 ... Anode, 7 ... Magnet, 8
...... Magnet rotating rod, 9 ... Sputter source case, 10 ...
... Insulator, 11 ... Power supply, 12 ... Shutter, 13 ... Substrate holder elevator / rotator, 14 ... Gas introduction system, 15 ... Exhaust system.

Claims (2)

(57) [Claims] 1. A magneto-optical recording film which sputters a rare earth-transition metal alloy target placed in a sputtering chamber and forms a magneto-optical recording film on a substrate which is moved and operated in a predetermined region in a sputter emission direction of sputtered particles. 0 [deg.] When the angle formed between the line connecting the target center point and an arbitrary point on the substrate surface and the substrate surface is [deg] and the length of the line segment is L [cm], 0 [deg.] cm] <L ≦ 11.25 [cm] and 0 [deg] <θ ≦ 90 [deg] or 11.25 [cm] <L ≦ 33.75 [cm] and 4 [deg / cm] × L-45 [deg] ≦ θ ≦ A method for manufacturing a magneto-optical recording film, wherein a substrate surface is arranged in a region (L, θ) satisfying a condition of 90 [deg]. 2. A method for manufacturing a magneto-optical recording film according to claim 1, wherein said rare earth-transition metal alloy target is sputtered by a magnetron type sputtering source.