JPH10202668A - Molding method for recording disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a stamper of long life for molding and mold by introducing a raw material gas composed of hydrocarbon gas, as a main component, ionizing the same, carrying out the deposit separation on the back of the stamper to form a diamond-shaped film to be coated thereon, supporting the stamper in a molding die cavity and injecting resin. SOLUTION: A diamond shaped film is formed on the back 8 of a stamper in an ordinary film manufacturing device. As the diamond-shaped film is formed on the back 8 of the stamper 1 of a molding die, the life of the stamper 1 can be prolonged to a large extent. Also as it is hard to form marks on the stamper 1, characteristics of a matrix surface of the stamper 1 are hard to be lowered, and the quality of a disk to be molded is good for a long time. Thus the stamper 1 of low wear resistance and low friction resistance is manufactured to achieve the realization of long life of the stamper 1, and a number of disks can be manufactured by one stamper 1 to achieve the reduction of the molding cost to a large extent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a recording disk such as a record, a compact disk, a magneto-optical disk, an optical disk and a laser disk.

[0002]

2. Description of the Related Art To manufacture a recorded recording medium such as a record or a disk, a plastic is charged into a mold cavity supporting a stamper (molding mold), and is pressurized. 2. Description of the Related Art Transfer of a surface shape to a molded article has been performed. FIG. 1 shows an example of such a molding die. FIG. 1 shows an injection mold for molding a laser disk or the like, which comprises a movable mold 2 and a fixed mold 5, and forms a molding cavity 7 when the movable mold is closed. . The sheet-shaped metal stamper 1 is supported on the mirror-finished surface 8 on the side of the cavity 7 of the movable mold 2, and the periphery thereof is further formed by an outer ring member 4.
Press by. The outer peripheral ring member 4 also forms the peripheral wall of the cavity. FIG. 1 shows a state in which the mold is closed, and a cavity 7 is formed. In this state, the resin is introduced from the supply port 3 through the gate 6 of the gate member 12 into the cavity 7 at a predetermined molding pressure, and is molded.

[0003]

The movable mold 2 is made of steel and quenched, and its surface 8 is hard-plated and polished with high precision. The reason for polishing the movable mold in this way is that the stamper slides on the surface 8 of the movable mold due to expansion and contraction due to heat. For example, if the temperature of the molten resin is 360 ° C., the temperature of the front surface 8 of the movable mold is 100 ° C., and the resin pressure is 400 kg / cm ² , the front surface of the stamper 1 is 360 ° C., and the back surface is 100 ° C.
And pressed by the above pressure. The stamper will then move along the surface 8 with heat and pressure. Therefore, when molding is repeatedly performed using the above-described mold, the back surface of the stamper 1 is damaged by each shot due to friction, cracks are generated, and crack marks are transferred to the surface of the molded product. . This problem can be solved to some extent by coating the surface 8 on the cavity side with a wear-resistant film such as TiN, but sufficient wear resistance and low friction cannot be obtained. An object of the present invention is to form a recording disk such as a disk using a stamper having a long life.

[0004]

According to the present invention, a back surface of a stamper serving as a molding master is polished, the stamper is positioned in a vacuum film forming chamber, and a raw material gas mainly composed of a hydrocarbon gas is introduced. To form a stamper coated with a diamond-like thin film by vapor deposition on the back surface of the stamper, supporting the stamper in a molding die cavity, and injecting a resin into the cavity. The present invention provides a method for molding a recording disk.

[0005]

According to the present invention, since the back surface of the stamper, which is a forming mold, is subject to friction and wear, the wear resistance is improved and the friction is reduced, and the service life of the stamper is greatly increased. As a result, since the stamper back surface is not damaged, the quality of the master die surface with which the recording disk such as the disk to be formed comes in contact does not decrease, so that the quality of the recording disk can be maintained for a long time.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The stamper used in the present invention is as follows.
Any method may be used as long as a diamond-like thin film is uniformly formed on the back surface of a stamper serving as a molding master. However, at present, there is hardly provided a method capable of forming a diamond-like film having a sufficiently large area and a sufficient smoothness at a practical film forming rate. Therefore, it is recommended to use the method described below. You.

Hereinafter, the present invention will be described in detail. The ionization deposition method, which is a basic technique of the present invention, is disclosed in Japanese Patent Application Laid-Open No. 58-174.
No. 507, JP-A-59-174508, and the like. In the embodiments of the present invention, a method and an apparatus based on the apparatuses described in these publications are used. However, other types of ionization vapor deposition techniques may be used as long as the ionization and acceleration of the hydrocarbon raw material can be performed. For example, a method of ionizing hydrocarbons by means such as glow discharge, microwave, pyrolysis, and shock wave is possible.

In carrying out the present invention, the method and apparatus described in the above-mentioned publication may be used as they are, or a film-forming place may be changed, or a film-forming area may be increased by operating an ion beam, or a diamond-like film may be used. In order to improve the quality of the film, an apparatus modified to perform ion deflection may be used. In the case of using the apparatus disclosed in the publication, the hydrocarbon gas is decomposed by thermionic emission from the hot filament, and the resulting gas contains many ionic species, and neutral molecules, atoms, radicals, and the like that remain without being decomposed. . For example, in the case of methane gas, which is a commonly used raw material, ions formed by thermionic emission by a hot filament are mainly CH ₄ ⁺ and CH ₃ ⁺ , and a small amount of ions such as CH ₂ ⁺ , CH ⁺ and C ⁺ , H ₂ ^+, and various forms of reactive species, such as radicals, anions, carbides, or unreacted materials.

When these particles collide with the substrate together, the ions are decomposed, leaving only carbon and developing a predetermined diamond structure. Normally, the development of the diamond structure is hindered by the mixture of neutral particles and various types of ions, and the crystals are reduced to fine particles. However, using ionization deposition,
Such microcrystallization does not occur, and a diamond-like thin film having a high surface smoothness can be obtained. In the present invention, the diamond-like thin film refers to a carbonaceous thin film formed by ionization deposition of a raw material gas containing a hydrocarbon as a main component or a thin film substantially the same as the carbonaceous thin film.

[0010] A preferred embodiment of a film formation apparatus for forming a diamond-like thin film on the stamper backside 8 to the film forming apparatus Figure 2. As this apparatus, an ion straight type (FIG. 2) or ion deflecting type (FIG. 3) described in Japanese Utility Model Application Laid-Open No. 59-174507, or any other apparatus can be used. Therefore, refer to the publication for film forming conditions and the like not described herein. FIG.
Referring to FIG. 1, reference numeral 10 denotes a vacuum vessel, and an exhaust system 18 is provided.
And a high vacuum of about 10 ^-6 Torr is applied. Reference numeral 12 'denotes a substrate holder for supporting the substrate S (stamper). In this case, the grid 13 of the voltage Va accelerates the flow of ions toward the substrate S. Reference numeral 14 denotes a filament which is heated by an AC power supply to generate thermoelectrons and is maintained at a negative potential. Reference numeral 15 denotes a supply port for a hydrocarbon gas as a raw material, and has an inlet 17 and a plasma excitation chamber 16 '. Further, a counter electrode 16 is arranged so as to surround the filament 14, and a voltage Vd
give. An electromagnetic coil 19 that surrounds the filament 14 and the counter electrode 16 and generates a magnetic field for confining the ionized gas is arranged. Therefore, the film quality can be changed by adjusting Vd, Va and the current of the coil.

[0011] will be described in detail film forming method by the apparatus of the film forming method FIG 2. First, the inside of the vacuum vessel 10 is set to a high vacuum up to 10 ^-6 Torr,
The exhaust system 18 is adjusted while operating a valve 22 to introduce a predetermined flow rate of methane gas, and a predetermined gas pressure, for example, 10 ^-1 T
orr. On the other hand, the filament 14 has an alternating current I
f, and heat is applied. A potential difference Vd is applied between the filament 14 and the counter electrode to form thermionic emission by the hot filament. Hydrocarbon gas such as methane gas supplied from the supply port 15 to the vacuum vessel 10 collides with thermoelectrons from the filament to generate positive pyrolysis ions and electrons. This electron collides with another pyrolysis ion. By repeating such a phenomenon, the methane gas becomes a positive ion of the thermal decomposition substance. The positive ions are accelerated by the negative potential Va applied to the grid 13 and accelerated toward the substrate S. For the conditions such as the potential, current, temperature, etc. of each part, please refer to publicly known materials in addition to the above-cited patent publications. In addition, as the plasma gas, in addition to methane gas, low molecular weight hydrocarbons, or one of them and oxygen, nitrogen,
Argon, neon, helium, or the like can be used.

[0012]

Embodiments of the present invention will be described below. Example 1 A stamper whose surface was nickel-plated and highly polished was placed at a predetermined position of a vacuum container 10, and the stamper back surface 8 on the movable mold side in FIG.
An argon gas was introduced thereinto, an arc discharge was performed at 10 ⁻² Torr, and the surface of the substrate was bombarded. Next, the argon gas in the container was exhausted, and then methane gas was introduced to adjust the gas pressure to 10 ^-1 . The magnetic flux density of the electromagnetic coil 19 is 400 gauss, the substrate voltage is -400 V, and the substrate temperature is 20
0 ° C. A current of 25 A was passed through the filament 14. A film having a thickness of 3 μm was produced. The obtained stamper was incorporated in the laser disk injection molding apparatus shown in FIG. 1, and injection molding was repeatedly performed at a pressure of 340 kg / cm ² . For comparison, injection molding was similarly performed using a stamper that did not cover the diamond-like thin film. Injection molding was performed in the same manner for the one coated with TiN by the conventional method. The results in Table 1 were obtained.

[0013]

[Table 1]

As can be seen from the table, in the molding die of the present invention, since the diamond-like thin film was used as the back surface of the stamper, the life of the stamper could be greatly extended. In addition, since the stamper is hardly damaged and the characteristics of the surface of the stamper die are hardly deteriorated, it is clear that the quality of the formed disk is good for a long period of time. As described above, according to the present invention, a stamper having low wear resistance and low frictional resistance is provided, and a longer life of the stamper is achieved.
A large number of disks can be manufactured with the same stamper, and a significant reduction in molding costs can be achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a molding die to which the present invention is applied.

FIG. 2 is a sectional view of a sectional view showing an apparatus for performing the method of the present invention.

[Explanation of symbols]

 Reference Signs List 1, 17 stamper 2 movable mold 3 resin supply port 4 outer ring member 5 fixed mold 6 gate 7 molding cavity 10 vacuum vessel 12 gate member 18 exhaust system 14 filament 15 material supply port 16 counter electrode 18 exhaust system 19 Electromagnetic coil

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G11B 3/70 G11B 3/70 Z B29L 17:00 (72) Inventor Hiroshi Tanabe 1-13-1 Nihonbashi, Chuo-ku, Tokyo DK Corporation

Claims (2)

[Claims] 1. A stamper serving as a molding master is positioned in a vacuum film forming chamber, a raw material gas containing a hydrocarbon gas as a main component is introduced, and this is vapor-deposited and deposited on the back surface of the stamper to coat a diamond-like thin film. A method for forming a recording disk, comprising forming a stamper, supporting the stamper on a stamper support surface in a molding die cavity, and injecting resin into the cavity. 2. The recording disk forming method according to claim 1, wherein a raw material gas mainly composed of a hydrocarbon gas is ionized and then vapor-deposited on the back surface of the stamper.