JP3213029B2 - Plasma processing apparatus for disk substrate and processing method thereof - Google Patents

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 plasma processing apparatus for intermittently transporting a disk substrate to be processed and sequentially performing a plasma processing while the disk substrate is stationary. The present invention relates to an apparatus and a plasma processing method using the same.

[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 to modify 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 repeating the step of feeding the substrate is widely used industrially. One example of this is disclosed in JP-A-62-502.
There is a sputter deposition apparatus for sequentially forming a multilayer film of a magnetic disk or an optical disk as described in JP-A-846.

On the other hand, in a high-frequency plasma, a method of performing etching with high energy ions or ion-assisted film formation utilizing a self-bias effect caused by asymmetry of an electrode area is known, such as reactive ion etching or a high hardness carbon film. Is formed. In these processes, the process is usually performed on the electrode to which a high frequency is applied. However, as disclosed in Japanese Patent Application Laid-Open No. 62-83471, by increasing the area of the high-frequency electrode, the process is performed on the ground side substrate. However, if the same treatment is performed, there is a great industrial effect. That is, considering the continuous multi-sheet processing as described above, the fact that the substrate can be kept at the ground potential was very advantageous in terms of the apparatus configuration.

[0004]

In the continuous plasma processing apparatus for a disk substrate using the conventional technique, 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 in that the thickness is not uniform, and desired processing cannot be performed.

[0005] This is because the plasma generated on both sides leaks and interferes from the holes of the disk substrate to be processed, resulting in spatially biased plasma, and particularly, the plasma concentrates around the hole circumference of the disk substrate. That was it.

An object of the present invention is to prevent plasma from leaking from a space surrounded by an electrode and a disk substrate to be processed in plasma processing of a disk substrate, and to concentrate plasma in a disk hole. What measures should be taken to prevent the processing effect near the hole from fluctuating.

[0007]

In order to solve the above problems, a plasma processing apparatus for a disk substrate according to the present invention is provided on a surface to be processed on both surfaces of a disk substrate where plasma is generated. And an electrode composed of a member having a shape capable of surrounding a space on the surface to be processed, and a member protruding at a position opposed to a hole in the center of the disk substrate. And 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 protruding tip of the electrode and the hole of the disk substrate are each held in a gap for preventing plasma leakage. I have. In general, it is widely known that the plasma can be blocked by reducing 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. In order to block plasma at such a gas pressure, in the former case, the interval is set to 3 mm or less, and In the case of (1), the interval must be 10 mm or less. The disk substrate plasma processing apparatus according to the present invention has a structure satisfying these conditions. That is, when the protruding tip of the electrode is at a high voltage, the distance between the protruding tip and the disc 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 set to the ground potential, it is possible to provide a margin for accuracy in the interval, thereby improving the operability of loading and transporting the disk substrate.

When the self-bias effect is used, the ratio of the area of the portion where the plasma contacts the electrode to the portion where the plasma contacts the processing portion is the area ratio where the self-bias is formed. In order to generate a sufficient self-bias voltage, this ratio needs to be at least twice or more, preferably three times or more.

In some cases, a tube for gas introduction and exhaust is connected to a part of the electrode.

As a more effective method for preventing the plasma from leaking from the space surrounded by the electrode and the disk substrate to be processed, a gap between the electrode body and the disk substrate to be processed is synchronized with the transport of the disk substrate. By changing it, there is a method of keeping the plasma at an interval required to block the plasma only when the plasma is being generated. This interval is generally 5 mm or less, but if it is 2 mm or less, the effect is further enhanced.

[0011]

According to the present invention, uniform plasma can be formed on a disk substrate by generating plasma without bias by preventing concentration of plasma in the hole. Further, since the plasma is confined and processed, the film adheres only to the inside of the disk substrate and the electrode to be processed, and cleaning is easy. Further, the influence on other adjacent processing units can be reduced.

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

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

[0014]

Next, an embodiment of the present invention will be described.

FIG. 1 shows the configuration of an embodiment of a plasma processing apparatus for a disk substrate according to the present invention.

A plasma processing apparatus according to the present invention transports at least one direction of a vacuum chamber 1 capable of evacuating to a pressure lower than the atmospheric pressure and a disk substrate 2 to be processed in the vacuum chamber 1 or a holder 3 having the disk substrate 2 mounted thereon. Transport mechanism 4, an electrode 5 for applying a high voltage to generate plasma, a ground potential member end 24c provided at a 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 keeping the inside of the vacuum chamber 1 at or below atmospheric pressure, and a valve for separating the vacuum chamber 1 from the exhaust mechanism 9. 9a.

In addition, the apparatus shown in FIG. 1 is provided with a charging chamber 10 for charging a substrate, an unloading chamber 11 for unloading a substrate, and a gate valve 12 for separating the charging chamber and the unloading chamber from the reaction chamber.

A transport mechanism 4 for transporting the disk substrate 2 or the holder 3 is provided inside these. Also,
The gas in the preparation chamber 10 and the gas in the take-out chamber 11 are exhausted by the exhaust mechanism 9 via the respective valves 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 is possible to have an electrode driving mechanism 6. In FIG. 2A, the plasma is confined by moving the electrode 5 and the earth cover 24 surrounding the electrode 5 together in a direction perpendicular to the holder 3 of the disk substrate.
It can be used for VD and the like.

2B, the electrode 5 to which a high voltage is applied surrounds the disk substrate 2 or the holder 3 of the disk substrate, and an earth cover 24 is provided so that plasma is not generated outside the electrode 5. It is a form that moves together. When high-frequency plasma is generated using such an electrode, a large voltage drop occurs on the substrate of the disk substrate 2, and reactive ion etching and formation of a hard carbon film can be performed.

FIG. 3C shows that the electrode protruding portion 5 a 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 each is electrically connected. In this device, the electrode protruding portion 5a and the ground potential member end 24c are connected to the electrode 5 and the ground cover 2a.
4, the position of the ground potential member end portion 24c with respect to the hole of the disk substrate 2 can be finely adjusted.

However, only one electrode is shown in this drawing, and the electrodes shown in FIG. 2 are actually used facing the disk substrate 2 or holder 3 to be processed. At this time, by independently controlling the gas pressure and gas flow rate, the applied voltage and the current, etc. of the two processing units, the difference in the processing efficiencies of the two processing units (film formation speed, film quality, etching speed, etc.) is minimized. Then, uniform plasma processing can be performed on both surfaces simultaneously.

FIG. 3 shows a process from introduction of a disk substrate to processing and discharge as an example of implementing a plasma processing method using the disk substrate plasma processing apparatus 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, and then, as shown in FIG. 3B, the electrode 5 is brought close to a distance where plasma does not leak from both sides of the disk substrate 2, A high voltage is applied from 7 to generate plasma. After the treatment, the plasma is stopped, and FIG.
As shown in (2), the electrode 5 is moved away from the disk substrate 2 again, and the disk substrate 2 is discharged.

By the way, the disk substrate shown in FIG.
Although introduced and carried out in one direction by the carrying mechanism 4, the carrying direction can be reversed. For example, the processing can be shifted from the state of FIG. 3A to the state of FIG. 3B and return to the state of FIG. 3A again.

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 is
The disk substrate 2 is mounted on the holder 3 and the rail 1
4 and 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. And take it out.

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

The substrate facing surface portion 5b of the electrode is attached and fixed to an insulating material 25. In addition, of 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.

The electrode side surface portion 5c is provided with an earth cover 24 outside the electrode side portion 5c to have a double structure. An earth cover end 24a is also provided outside the electrode end 5d to form a double structure.

The electrode protruding portion 5a has a ground potential member 24b provided 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 disk substrate 2.

Further, the ground potential member 24b is provided so that the gaseous substance supplied from the gas introduction mechanism 8 can be introduced.
Dozens of gas inlets 24d are provided in a hollow tube. Dozens of gas inlets 5e are provided in the electrode protruding portion 5a surrounding the outside so that gaseous substances 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 23 is provided between the adjacent parts 4a. The holder 3 of the disk substrate is carried in through the gap 23.

A cylinder 22 is attached to four corners of an insulating material 25 supporting the entire electrode 5. By simultaneously moving the cylinder 22, the electrode 5 and the earth cover 24 can be moved together, and the gap 2
3 can be changed.

The portion of the electrode side surface 5c to which a high voltage is applied is inside the double structure, and the outside is the ground cover 2
4 is the ground potential. For this reason, even if the disk 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 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 swings right and left, it only comes into contact with the ground potential member 24c. Contact and no problem occurs. In this embodiment, two sets of electrode facing surfaces 5 are provided.
Exhaust mechanism 9 is connected to each back surface of b and 5b.

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

Next, an example in which a magnetic disk is actually manufactured by using the above apparatus will be described.

20 sets of 5.25 inch diameter disk substrates mounted on a holder one by one
And evacuated.

A pair of a Cr target for a base film and a CoCrTa alloy target for a magnetic film are set in advance in the sputtering cathode of the sputtering chamber 16 and once evacuated, argon is introduced, and a gas pressure of 10 is set.
DC plasma was generated while maintaining the pressure at mTorr, and after performing dummy sputtering for 1 to 2 hours, the plasma was stopped.

Next, the single holder is taken out of the chamber 19.
The substrate was conveyed toward the side, and when it reached the pre-processing chamber 20, the substrate was once heated and heated to about 200 ° C.

Next, at the same time as transferring this holder to the sputtering chamber 16, the next holder was sent from the charging chamber 15 to the pretreatment chamber 20. As described above, the holders were sequentially sent out while performing the processing in each processing chamber. In this way, in the sputtering chamber 16, about 30 Cr was added to the disk substrate.
0 nm sputtered, and then a CoCrTa alloy
Sputtered. Then, it was transferred to the plasma CVD chamber 18.

At the time of transfer to the plasma CVD chamber 18, the inside of the processing tank is evacuated in advance, and the electrode 5 is moved in a direction away from the disk substrate.
An interval through which the holder 3 easily passes was secured. When the holder 3 reaches the processing section and stops, the electrode 5 is moved in the direction of the disk substrate to reduce the distance between the gaps 23,
The distance between the electrode and the holder has been reduced.

Then, CH ₄ gas was introduced, and the pressure was 50 m.
The flow rate and the pumping speed were adjusted so that Torr was constant. Thereafter, 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 one minute, the application of the voltage is stopped, the electrode 5 is moved away from the disk substrate 2 again, the gas is stopped, and the gas is evacuated. A disk substrate was introduced.

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

Thereafter, the apparatus was stopped and the inside of the processing chamber was inspected, but no film adhesion was observed except for the electrode portion, and no generation of dust or the like was observed.

The film thickness distribution of the protective film formed on the disk substrate was about ± 10% in the related art, but ± 3%.
%.

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

[0049]

According to the present invention, the generated plasma can be confined only to a necessary portion. Therefore, a uniform film can be formed without the plasma being concentrated on the inner and outer circumferential portions of the disk substrate to be processed. In addition, there is no film attached to unnecessary portions or heating by plasma, which is a great effect for maintenance of the apparatus.

Therefore, it is possible to provide an efficient apparatus for sequentially transporting a large number of disk substrates and performing plasma processing without bias, thereby greatly expanding the applicable range of the multi-step continuous processing apparatus.

[Brief description of the 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 cross-sectional view showing an example of the structure of an electrode used in an embodiment of the present invention.

FIG. 3 is a 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 viewed from the chamber.

FIG. 6 is a magnetic disk drive 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 protruding part 5b Electrode facing surface part 5c Electrode side part 5d Electrode end bent inward 5e Gas inlet of protruded electrode 6 Drive mechanism 7 Voltage applying device Reference Signs List 8 gas introduction mechanism 9 exhaust mechanism 9a valve 10 charging chamber 11 extraction chamber 12 gate valve 13 processing unit 14 rail 15 charging chamber 16 sputter chamber 17 partition chamber 18 plasma CVD chamber 19 extraction chamber 20 pretreatment chamber 22 cylinder 23 gap section 24 earth Cover 24a Ground cover end 24b Ground potential member 24c Ground potential member end 24d Gas inlet of ground potential member 25 Insulation material 26 Magnetic disk 27 Head 28 Arm 29 Motor 30 Cover

──────────────────────────────────────────────────の Continued from the front page (72) Inventor Noriyuki Shige 2880 Kozu, Kozuhara, Odawara City, Kanagawa Prefecture Inside the Odawara Plant, Hitachi, Ltd. (72) Keigo Iechika 2880 Kozu, Kozu, Odawara City, Kanagawa Prefecture, Japan Inside the Odawara Plant, Hitachi, Ltd. (72) Inventor Yoshinori Honda 2880 Kozu, Odawara-shi, Kanagawa Prefecture Inside Odawara Plant, Hitachi, Ltd. (72) Inventor Shigehiko Fujimaki 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture, Hitachi, Ltd. inventor Ryo Kito Kanagawa Prefecture, Totsuka-ku, Yokohama-shi Yoshida-cho, 292 address Hitachi, Ltd. production technology in the Laboratory (56) reference Patent Sho 57-191880 (JP, a) (58 ) investigated the field (Int.Cl. ⁷ , DB name) C23C 16/00-16/56 H01L 21/205 C23C 14/00-14/58

Claims (11)

(57) [Claims] 1. A vacuum vessel, exhaust means for keeping the pressure in the vacuum vessel lower than atmospheric pressure, an electrode for generating plasma in the vacuum vessel, and applying a voltage to the electrode For supplying a gaseous substance to the plasma generating unit as one set, and two sets of this set in one vacuum vessel, and both sides of the disk substrate are subjected to plasma. In the plasma processing apparatus for processing, the two electrodes are formed of an electrode member having a shape capable of surrounding a space where plasma is generated on both surfaces to be processed of the disk substrate, and a projection provided at a position opposed to a hole at the center of the disk substrate. And a plasma processing apparatus for a disk substrate. 2. A disk substrate plasma processing apparatus according to claim 1, wherein said electrode member has a shape capable of surrounding a space on a processing surface of said disk substrate, said electrode member comprising an electrode, and said electrode member faces a hole at a center portion of said disk substrate. A plasma processing apparatus for a disk substrate, comprising: a mechanism in which a protruding electrode member provided at a position to be moved is independently or integrally movable relative to a disk substrate or a holder of the disk substrate. 3. The plasma processing apparatus for a disk substrate according to claim 1, wherein a ground potential member is provided at a tip end of the protruding electrode member constituting the electrode. . 4. The plasma processing apparatus for a disk substrate according to claim 1, wherein a gaseous substance introduction port is provided on a side surface of the protruding electrode member constituting the electrode, and the electrode is connected to the electrode member. A plasma processing apparatus for a disk substrate, comprising: a mechanism for directly feeding a gaseous substance into a space surrounded by a processing target portion. 5. A plasma processing apparatus for a disk substrate according to claim 1, wherein a gas exhaust port is provided in a part of the electrode in the vacuum vessel, and the gas exhaust port is surrounded by the electrode and the processing unit. A plasma processing apparatus for a disk substrate, wherein a gas in a space is exhausted from the exhaust port. 6. The plasma processing apparatus for a disk substrate according to claim 1, wherein the plasma is generated by applying a voltage to an electrode in a vacuum vessel. A plasma processing apparatus for a disk substrate, wherein the contact area is at least twice as large as the area of the plasma contacting the processing section and the grounded electrode member. 7. A magnetic disk manufacturing apparatus comprising the disk substrate plasma processing apparatus according to any one of claims 1 to 6. 8. A plasma processing method for a disk substrate performed by using a plasma processing apparatus having an electrode for generating plasma in a vacuum vessel and a space on a surface to be processed on both surfaces of the disk substrate where plasma is generated. In performing the plasma treatment, the end of the electrode, 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 protruding portion in the hole of the disk substrate,
A plasma processing method for a disk substrate, wherein the electrodes are held in gaps for preventing plasma leakage, and the electrodes are relatively retracted from the disk substrate or the holder when the disk substrate is loaded or unloaded. 9. A treated disc substrate or at least one holder mounted to be processed disk substrate of the plasma a continuous processing method of feeding in order continuously to a plurality of vacuum chambers, with at least one vacuum chamber, in claim 8 A plasma continuous processing method, wherein the plasma processing is performed by the disk substrate plasma processing method described above. 10. A magnetic disk, wherein a protective film is formed on a magnetic film of a magnetic disk substrate by the disk substrate plasma processing method according to claim 8 or the plasma continuous processing method according to claim 9. Production method. 11. A method of manufacturing a magnetic disk, comprising forming at least a recording layer and a protective layer on a magnetic disk substrate in this order by using the magnetic disk manufacturing apparatus according to claim 7.
A protective layer forming step, wherein at least the magnetic disk substrate is carried into a plasma processing chamber which is the vacuum vessel according to claim 1, a hydrocarbon gas is introduced into the plasma processing chamber, Manufacturing a magnetic disk by applying a high-frequency voltage to electrodes constituting a chamber to generate plasma, forming a carbon film on the magnetic disk substrate, and carrying out the magnetic disk substrate. Method.