JPH05140752A - Plasma treating device for disk substrate and its treatment - Google Patents

Abstract

PURPOSE:To enable the uniform film formation on a disk substrate with good efficiency by constituting electrodes of projecting parts facing the hole of the disk substrate and parts enclosing a plasma space to prevent the leakage and biasing of the plasma. CONSTITUTION:The electrodes 5 and ground potential members 24b are disposed on both sides of the disk substrate 2 which is to be treated and is inserted from a spacing part 23 of a vacuum chamber 1. The electrodes 5 are constituted of the projecting parts 5a facing the hole of the disk substrate 2, the parts 5b facing the substrate as well as flank parts 5c and end parts 5d. Gas introducing ports 5e are provided on the flanks of the projecting parts 5a. The electrodes 5 are made movable forward and backward by a cylinder 22. Gas introducing ports 4d are provided in the ground potential members 24b as well. Gases from these gas introducing ports 5e, 24d are introduced into the vacuum chamber 1 and a high-frequency voltage is impressed to the electrodes 5 to generate plasma. This plasma is confined in the plasma space enclosed by the respective electrode members 5a to 5d and the leakage of the plasma from the hole of the disk substrate 2 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and a processing method for a disk substrate, and more particularly to a continuous processing type plasma processing in which a disk substrate to be processed is intermittently conveyed and sequentially processed while the disk substrate is stationary. The present invention relates to an apparatus and a plasma processing method using the apparatus.

[0002]

2. Description of the Related Art A substrate to be treated as it is or mounted on a holder or the like is sequentially fed into a reactor to generate plasma to modify or etch the surface of the substrate to be treated, or the surface of the substrate to be treated. An apparatus for continuously plasma-treating a large number of substrates by forming a thin film on the substrate and then repeating the step of feeding the substrate is widely used industrially. As one example of this, Japanese Patent Laid-Open No. 62-502
There is a sputtering film forming apparatus for sequentially forming a multilayer film of a magnetic disk or an optical disk as described in Japanese Patent No. 846.

On the other hand, in high frequency plasma, there is known a method of performing etching by high-energy ions or ion-assisted film formation by utilizing a self-bias effect caused by asymmetry of electrode area, such as reactive ion etching or high hardness carbon film. Is being formed. In these processes, the process is usually performed on the electrode on the side to which a high frequency is applied. However, as disclosed in JP-A-62-83471, by increasing the area of the high frequency electrode on the ground side substrate. However, if the same treatment is performed, it has a great industrial effect. That is, in consideration of the above-mentioned continuous multi-layer processing, it was very advantageous in terms of the apparatus configuration that the substrate could be kept at the ground potential.

[0004]

In the continuous plasma processing apparatus for a disk substrate using the above-mentioned prior art, when plasma processing is performed on both surfaces of the disk substrate at the same time, particularly, a film is formed on the circumference of the hole of the disk substrate. There is a problem that the desired treatment cannot be performed because the thickness is not uniform.

The cause of this is that plasma generated on both sides leaks from and interferes with the holes of the disk substrate to be processed, resulting in spatially biased plasma, and in particular, the plasma concentrates at the circumferential portion of the hole of the disk substrate. There was that.

The problem to be solved by the present invention is to prevent the plasma from leaking from the space surrounded by the electrode and the disk substrate to be processed in the plasma processing of the disk substrate, and the plasma is concentrated in the disk hole. Therefore, what kind of means should be taken to prevent the processing effect in the vicinity of the hole from fluctuating.

[0007]

In order to solve the above-mentioned problems, a plasma processing apparatus for a disk substrate according to the present invention is arranged so that plasma is generated on the surfaces to be processed on both sides of the disk substrate so as to face each surface. And an electrode composed of a member having a shape capable of enclosing a space on the surface to be processed and a member protruding at a location facing the hole in the center of the disk substrate, and at the time of plasma processing, the end portion of the electrode And the end portion of the disk substrate or the end portion of the holder on which at least one substrate to be processed is mounted, and the protruding tip end portion of the electrode and the hole portion of the disc substrate are respectively held in a gap that prevents plasma leakage. There is. In general, it is widely known that plasma can be shielded by narrowing the distance between the high-voltage electrode and the ground potential portion and the distance between the same-potential portions. However, the gas pressure at which normal plasma processing is performed is about 0.01 to 0.5 Torr, and in the case of such a gas pressure, in the former case, the interval is set to 3 mm or less and the latter is cut off. In this case, the distance must be 10 mm or less. The plasma processing apparatus for a disk substrate according to the present invention has a structure that satisfies these conditions. That is, when the protruding tip of the electrode has a high voltage, the distance between it and the disk substrate hole is 3 mm or less, and when the protruding tip is at the ground potential, it is 10 mm or less. In particular, when the tip is at the ground potential, it is possible to provide a precise margin for the interval, and the operability of loading and carrying the disk substrate can be improved.

When utilizing the above-mentioned self-bias effect, the ratio of the area of the portion in contact with the plasma to the electrode and the area of the portion in contact with the plasma to the processing portion is the area ratio at which the self-bias is formed. In order to generate a sufficient self-bias voltage, this ratio must be at least 2 times or more, preferably 3 times or more.

Further, a pipe for introducing and exhausting gas may be connected to a part of the electrode.

As a more effective method for preventing plasma from leaking from the space surrounded by the electrode and the disk substrate to be processed, the gap between the electrode body and the disk substrate to be processed is synchronized with the transportation of the disk substrate. There is a method in which the distance is maintained so that the plasma is interrupted only when the plasma is generated by changing the plasma. This distance is generally 5 mm or less, but it is more effective if it is 2 mm or less.

[0011]

According to the present invention, uniform plasma is generated by preventing concentration of plasma in the holes, and uniform film formation can be performed on the disk substrate. Further, since the plasma is confined for processing, the film adheres only to the inside of the disk substrate to be processed and the electrode, and cleaning is easy. Further, it is possible to reduce the influence on other adjacent processing units.

In addition to these, in the processing method using the large bias voltage generated on the disk substrate side by increasing the area of the electrode for applying a high frequency as described above, the leakage of plasma reverses the relationship of the electrode area. This can solve the fatal problem that the expected effect cannot be obtained at all.

Generally, if a blind plate is provided in the hole of the disk substrate, plasma concentration in the hole can be prevented. However, in practice, the blind plate set not only causes a decrease in the productivity of the disc substrate manufacturing, but also causes generation of dust and the like, resulting in impaired product performance. According to the present invention, plasma concentration can be easily avoided without such drawbacks.

[0014]

EXAMPLES Next, examples of the present invention will be described.

FIG. 1 shows the configuration of an embodiment of the plasma processing apparatus for disk substrates of the present invention.

In the plasma processing apparatus according to the present invention, at least the vacuum chamber 1 that can be evacuated to a pressure lower than atmospheric pressure, and the disk substrate 2 or the holder 3 on which the disk substrate 2 to be processed is transported in at least one direction. Transport mechanism 4, an electrode 5 for applying a high voltage to generate plasma, and a ground potential member end 24c provided on the protruding electrode tip, and a voltage applying device for applying a high voltage to the electrode 5. 7, a gas introduction mechanism 8 for introducing a gaseous substance into the plasma generation region, an exhaust mechanism 9 for maintaining the inside of the vacuum chamber 1 at atmospheric pressure or less, and a valve for partitioning the vacuum chamber 1 and the exhaust mechanism 9. 9a.

In addition, the apparatus shown in FIG. 1 is provided with a charging chamber 10 for charging a substrate, a take-out chamber 11 for taking out a substrate, and a partition valve 12 for separating the charging chamber and the take-out chamber from the reaction chamber.

Inside these, a transfer mechanism 4 for transferring the disk substrate 2 or the holder 3 is provided. Also,
The gas in the charging chamber 10 and the gas in the unloading chamber 11 is exhausted by the exhaust mechanism 9 via the valve 9a.

The charging chamber 10 and the take-out chamber 11 may be omitted.

The structure of the electrode used in this embodiment is, for example,
As shown in FIG. 2, it may have an electrode driving mechanism 6. In FIG. 2, (a) shows that the electrode 5 and the earth cover 24 surrounding the electrode 5 are moved together in the vertical direction with respect to the holder 3 of the disk substrate to confine the plasma.
It can be used for VD and the like.

In (b), the electrode 5 itself to which a high voltage is applied surrounds the disk substrate 2 or the holder 3 of the disk substrate, and the earth cover 24 is provided so that plasma is not generated outside the electrode 5, and the whole is covered. It is a format that works together. When high-frequency plasma is generated using such an electrode, a large voltage drop occurs in the substrate of the disc substrate 2, and reactive ion etching and formation of a hard carbon film can be performed.

In (c), the electrode protrusion 5a is provided separately from the electrode 5, and the ground potential member 24 is provided from the ground cover 24.
c are provided separately, and are electrically connected to each other. In this structure, the electrode projection 5a and the ground potential member end 24c are connected to the electrode 5 and the ground cover 2
4 and the position of the ground potential member end 24c with respect to the hole of the disk substrate 2 can be finely adjusted.

However, in this figure, only one electrode is shown, and in practice, the electrode shown in FIG. 2 is used facing the disk substrate 2 or holder 3 to be processed. At this time, the gas pressure and the gas flow rate of the two processing units, the applied voltage and the current are independently controlled to minimize the difference in the processing efficiency between the two processing units (the film forming rate, the film quality, the etching rate, etc.). By doing so, it is possible to perform uniform plasma treatment on both sides simultaneously.

FIG. 3 illustrates steps from the introduction of the disk substrate to the processing and discharge as an example of carrying out the plasma processing method using the plasma processing apparatus for the disk substrate of FIG.

That is, in the case of introducing a disk substrate, as shown in FIG.
3 and the disk substrate 2 is set in the processing unit 13, the electrodes 5 are brought closer to both sides of the disk substrate 2 to a distance at which plasma does not leak, as shown in FIG. A high voltage is applied from 7 to generate plasma. After the processing, after stopping the plasma, FIG.
As shown in, the electrode 5 is moved away from the disk substrate 2 again, and the disk substrate 2 is ejected.

By the way, the disk substrate shown in FIG.
Although it was introduced and carried out in one direction by the carrying mechanism 4, it is also possible to carry it in the opposite direction. For example, the process can be moved from the state of FIG. 3A to the state of FIG. 3B and returned to the state of FIG.

FIG. 4 shows an example of a magnetic disk manufacturing apparatus to which the plasma processing apparatus of the present invention is applied. This device
Mount the disk substrate 2 on the holder 3 and attach it to the rail 1
It is transported on the substrate No. 4 and is moved in the order of the preparation chamber 15, the pretreatment chamber 20, the sputtering chamber 16, the partition chamber 17, the plasma CVD chamber 18, and the take-out chamber 19 to form a base film, a magnetic film, and a protective film in this order. To take out.

The mechanism of the present invention is attached to the plasma CVD chamber 18 of these processing chambers. FIG. 5 shows a vertical cross section of this portion. This structure is similar to that shown in FIG.
Here, two sets of electrodes 5 having such a structure are used, and they are arranged to face each other with the plasma generation space inside.

The substrate facing surface portion 5b of the electrode is attached and fixed to the insulating material 25. In addition, the electrode side surface portion 5c,
The electrode end 5d close to the disk substrate 2 is bent inward so as to be substantially parallel to the holder of the disk substrate to prevent plasma leakage.

Further, the electrode side surface portion 5c has a double structure in which an earth cover 24 is provided on the outer side thereof. Further, the earth cover end 24a is also provided outside the electrode end 5d to form a double structure.

The electrode protrusion 5a is provided with the ground potential member 24b therein and has a double structure. The ground potential member 24b is connected to a ground potential member end 24c provided near the hole of the disc substrate 2.

Further, the ground potential member 24b is provided so that the gaseous substance supplied from the gas introducing mechanism 8 can be introduced.
The hollow tube is provided with dozens of gas inlets 24d. The electrode projecting portion 5a surrounding the outside is also provided with several tens of gas introduction ports 5e so that a gaseous substance can be introduced.

The earth cover ends 2 of the two sets of electrodes 5 outside the respective parallel bent electrode ends 5d.
A gap portion 23 is provided between the 4a. The disk substrate holder 3 is carried in through the gap 23.

Cylinders 22 are attached to the four corners of the insulating material 25 that supports the entire electrode 5. By moving the cylinder 22 at the same time, the electrode 5 and the earth cover 24 can be moved together, and the gap 2
The interval of 3 can be changed.

The portion of the electrode side surface portion 5c to which a high voltage is applied is the inside of the double structure and the outside is the earth cover 2.
It has a ground potential of 4. Therefore, even if the disc substrate holder 3 is displaced, the ground potentials come into contact with each other and no problem occurs. Further, by setting the inner diameter of the ground potential member end portion 24c to be equal to or larger than the inner diameter of the hole of the disk substrate 2, even if the disk substrate 2 sways to the left and right, only the ground potential member 24c comes into contact with the same potential. It does not cause any problems. In this embodiment, two sets of electrode facing surface portions 5 are used.
An exhaust mechanism 9 is connected to the back surfaces of b and 5b.

In the manufacturing apparatus of this embodiment, the pretreatment chamber 2
Although 0 may be simply heated, it may be configured to have the same structure as the plasma CVD chamber 18 and to lightly etch the substrate surface by generating plasma of an inert gas such as argon.

Next, an example of actually manufacturing a magnetic disk using the above apparatus will be described.

20 sets of disk holders each having a 5.25 inch diameter disk substrate mounted in a holder 15
And was evacuated.

In the sputtering cathode of the sputtering chamber 16, a pair of a Cr target for a base film and a CoCrTa alloy target for a magnetic film were set in advance, and after evacuating once, argon was introduced to a gas pressure of 10
A direct current plasma was generated while maintaining mTorr, dummy sputtering was performed for 1 to 2 hours, and then the plasma was stopped.

Next, one of the holders is taken out from the chamber 19
The substrate was conveyed toward the side, and when it reached the pretreatment chamber 20, it was once stopped and heated, and the substrate was heated to about 200 ° C.

Next, this holder was conveyed to the sputtering chamber 16 and at the same time, the next holder was sent from the charging chamber 15 to the pretreatment chamber 20. In this way, the holders were sequentially sent out while performing processing in each processing chamber. In this way, about 30 Cr is deposited on the disk substrate in the sputtering chamber 16.
0 nm sputter, then CoCrTa alloy 50 nm
Sputtered. Then, it was transported to the plasma CVD chamber 18.

At the time of transportation to the plasma CVD chamber 18, the inside of the processing tank is evacuated and the electrode 5 is moved in a direction away from the disk substrate.
The space for the holder 3 to pass easily was secured. When the holder 3 reaches the processing unit and stops, the electrode 5 is moved toward the disk substrate to reduce the gap 23,
The distance between the electrode and the holder was reduced.

Then, CH ₄ gas was introduced, and the pressure was 50 m.
The flow rate and pumping speed were adjusted so that Torr was kept constant. Then, a high voltage having a frequency of 13.56 MHz was applied to generate plasma. The effective power was 2 kW.

After holding the plasma for 1 minute, the voltage application is stopped, the electrode 5 is moved away from the disk substrate 2 again, the gas is stopped and the gas is exhausted, and then the disk substrate holder is sent to the take-out chamber 19 and at the same time, A disk substrate was introduced.

By repeating the above cycle, 2
A protective film was formed on a disk substrate mounted on 0 holder.

After that, the apparatus was stopped and the inside of the processing chamber was inspected, but no film adhesion was observed except for the electrode section, and no generation of dust was observed.

Further, the film thickness distribution of the protective film formed on the disk substrate is about ± 10% in the conventional case, but is ± 3.
Improved to%.

In the magnetic disk device as shown in FIG. 6 in which the manufactured magnetic disk is provided with a magnetic head, a motor, an arm and the like, the variation in electric output is about ± 10% in the conventional case. Was improved to ± 3%. This is because the thickness distribution of the protective film is improved and the leakage magnetic field from the magnetic head becomes more uniform on the magnetic disk substrate.

[0049]

According to the present invention, the generated plasma can be confined only in a necessary portion. Therefore, the plasma can be prevented from being concentrated on the inner and outer circumferential portions of the disk substrate to be processed, and uniform film formation can be performed. In addition, a film is not attached to unnecessary portions and plasma is not heated, which is very effective for maintenance of the apparatus.

Therefore, it is possible to provide an efficient apparatus for carrying out plasma processing without unevenness by sequentially transporting a large number of disk substrates, and it is possible to broaden the range of application of the multi-step continuous processing apparatus.

[Brief description of drawings]

FIG. 1 is a sectional view showing a basic configuration of an embodiment of a plasma processing apparatus according to the present invention.

FIG. 2 is a sectional view showing a structural example of an electrode used in an example of the present invention.

FIG. 3 is a cross-sectional view showing an example of a plasma processing method according to the present invention.

FIG. 4 is a front view showing the configuration of another embodiment of the present invention.

5 is a cross-sectional view of the plasma CVD unit of the apparatus shown in FIG. 4 as seen from the take-out chamber side.

FIG. 6 is a magnetic disk device using a magnetic disk manufactured according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum tank 2 Disk substrate 3 Holder 4 Transfer mechanism 5 Electrode 5a Electrode protrusion 5b Electrode substrate facing surface portion 5c Electrode side surface portion 5d Inner bent electrode end portion 5e Protruding electrode gas inlet 6 Drive mechanism 7 Voltage applying device 8 gas introduction mechanism 9 exhaust mechanism 9a valve 10 charging chamber 11 discharge chamber 12 partition valve 13 processing unit 14 rail 15 charging chamber 16 sputter chamber 17 partition chamber 18 plasma CVD chamber 19 discharge chamber 20 pretreatment chamber 22 cylinder 23 gap 24 earth Cover 24a Ground cover end 24b Ground potential member 24c Ground potential member end 24d Ground potential member gas inlet 25 Insulating material 26 Magnetic disk 27 Head 28 Arm 29 Motor 30 Cover

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noriyuki Shigeyuki 2880 Kozu, Odawara, Kanagawa Stock company Hitachi Ltd. Odawara factory (72) Inventor Keigo Iechika 2880 Kozu, Odawara Kanagawa Hitachi Odawara In-house (72) Inventor Yoshinori Honda 2880 Kozu, Odawara, Kanagawa Stock company Hitachi Ltd. Odawara Factory (72) Inventor Naruhiko Fujimaki, 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Stock company Hitachi, Ltd. In-house (72) Inventor Ryo Kito, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd.

Claims (12)

[Claims] 1. A vacuum container, an evacuation means for keeping the pressure in the vacuum container lower than atmospheric pressure, an electrode for generating plasma in the vacuum container, and a voltage applied to the electrode. For supplying a gaseous substance to the plasma generation unit as a set, and two sets of the plasma processing unit are provided in one vacuum container. In the plasma processing apparatus for processing, the two electrodes are an electrode member having a shape capable of enclosing a space where plasma is generated on both surfaces of the disk substrate, and a protrusion provided at a position facing the hole at the center of the disk substrate. A plasma processing apparatus for a disk substrate, comprising: 2. The plasma processing apparatus for a disk substrate according to claim 1, wherein an electrode member having a shape capable of enclosing a space on a surface to be processed of the disk substrate, which constitutes an electrode, and a hole in a central portion of the disk substrate are opposed to each other. A plasma processing apparatus for a disk substrate, characterized in that the protruding electrode members provided at the positions to be provided are provided with a mechanism capable of moving relatively from the disk substrate or the holder of the disk substrate individually or integrally. 3. The plasma processing apparatus for a disk substrate according to claim 1 or 2, further comprising a ground potential member at a tip portion of a protruding electrode member which constitutes an electrode. .. 4. The plasma processing apparatus for a disk substrate according to claim 1, wherein an inlet for a gaseous substance is provided at a side surface of a protruding electrode member that constitutes an electrode, A plasma processing apparatus for a disk substrate, having a mechanism for directly feeding a gaseous substance into a space surrounded by a portion to be processed. 5. The plasma processing apparatus for a disk substrate according to claim 1, wherein a gas exhaust port is provided in a part of the electrode inside the vacuum container and is surrounded by the electrode and the processing section. A plasma processing apparatus for a disk substrate, wherein the gas in the space is exhausted from the exhaust port. 6. The plasma processing apparatus for a disk substrate according to claim 1, wherein when plasma is generated by applying a voltage to an electrode inside the vacuum container, the plasma is generated on the electrode. A plasma processing apparatus for a disk substrate, characterized in that the contact area is at least twice as large as the area of the plasma contacting the processing part and the grounded electrode member. 7. A magnetic disk manufacturing apparatus including the disk substrate plasma processing apparatus according to claim 1. Description: 8. A magnetic disk device configured by attaching at least a magnetic head, a motor, and an arm to the magnetic disk manufactured by the magnetic disk manufacturing apparatus according to claim 7. 9. A plasma processing method for a disk substrate, which is carried out by using a plasma processing apparatus having an electrode for generating plasma and a space on the surface to be processed on both surfaces of the disk substrate where plasma is generated, in a vacuum container. In performing the plasma treatment, the end of the electrode is at the end of the disk substrate or the end of the holder on which at least one substrate to be processed is mounted, and the electrode protrusion is at the hole of the disk substrate.
A plasma processing method for a disk substrate, which is characterized in that the electrodes are relatively retracted from the disk substrate or the holder when the disk substrate is carried in and out, respectively, being held in a gap that prevents plasma leakage. 10. A plasma continuous processing method in which a disk substrate to be processed or a holder on which at least one disk substrate to be processed is mounted is sequentially sent to a plurality of vacuum chambers, and at least one vacuum chamber is provided with at least one vacuum chamber. A plasma continuous processing method, wherein plasma processing is performed by the plasma processing method for a disk substrate described above. 11. A magnetic disk characterized by forming a protective film on a magnetic film of a magnetic disk substrate by the plasma processing method for a disk substrate according to claim 9 or the plasma continuous processing method according to claim 10. Production method. 12. A method of manufacturing a magnetic disk, wherein at least a recording layer and a protective layer are formed in this order on a magnetic disk substrate by using the magnetic disk manufacturing apparatus according to claim 7.
The protective layer forming step constitutes at least the step of loading the magnetic disk substrate into the plasma processing chamber according to claim 1, the step of introducing a hydrocarbon gas into the plasma processing chamber, and the processing chamber. A method of manufacturing a magnetic disk comprising: a step of applying a high frequency voltage to electrodes to generate plasma to form a carbon film on the magnetic disk substrate; and a step of unloading the magnetic disk substrate.