JP4081981B2 - Manufacturing method of optical disk medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a method for manufacturing an optical disk medium, and more specifically, it is possible to manufacture a low-noise and high-quality optical disk medium having a constant state by flattening the substrate surface before film formation.The present invention relates to an optical disk medium manufacturing method.
[0002]
[Prior art]
  An optical information recording method using laser light has been put to practical use as a large-capacity memory because it enables non-contact and high-speed access to a large amount of information. As an optical recording / reproducing medium using such an optical information recording method, a read-only type known as a compact disc or a laser disc, a write-once type that can be recorded by the user himself, and a repetitive recording on the user side. It can be classified as a rewritable recording / reproducing medium that can be reproduced.
[0003]
  The recordable and rewritable optical information recording / reproducing media are being used as an external memory of a computer, a document, and an image file. The rewritable optical information reproducing medium includes a phase change type optical disk that records information by using a phase change of a recording film and a magneto-optical disk that records information by using a change in the magnetization direction of a perpendicular magnetization film. is there. Among the above, the phase change type optical disc does not require an external magnetic field required for the magneto-optical disc when recording information, and moreover, overwriting of recorded information, that is, overwriting can be easily performed. In the future, it is expected to become the mainstream of rewritable optical information recording / reproducing media.
[0004]
  Conventionally, a rewritable phase change type optical disk using a phase change between a crystal and an amorphous layer of a recording film by irradiation with a laser beam has been used. In a phase change optical disc, the recording film is irradiated with high-power laser light, and the temperature of the recording film is locally increased to generate a phase change between the crystal and the amorphous state of the recording film. We are recording. Reproduction of recorded information is performed by irradiating laser light having a relatively low power as compared with recording and detecting a change in optical constant of the information recording unit as a reflected light intensity difference.
[0005]
  The recording film of the phase change optical disc uses chalcogenide-based materials, such as GeSbTe-based, InSbTe-based, and AgInSbTe-based materials. It is formed by a film forming method such as an electron beam vacuum deposition method or a sputtering method. The state of the recording film immediately after film formation is a kind of amorphous state, and information is recorded on this recording film to form an amorphous recording portion, so that the entire recording film is made crystalline. Initialization processing is performed. Recording is performed by forming an amorphous portion in the crystallized state.
[0006]
  A general recording / reproducing method for a phase change optical disc is performed by performing crystallization or amorphous by changing the power of laser light between two levels. That is, at the time of recording, when the recording film is irradiated with a laser beam having a power capable of raising the temperature of the recording film above the melting point, and the irradiated portion becomes an amorphous state when cooled, on the other hand, when erasing information The recording film is irradiated with a laser beam having such a power that the temperature of the recording film reaches a temperature not lower than the crystallization temperature and not higher than the melting point. Reproduction is read as reflected light intensity difference by irradiating with low power laser light.
[0007]
  The recording film constituting the phase change type optical disc as described above is formed on a transparent disc substrate on which a spiral or concentric guide groove, that is, a recording track (land portion: concave portion and groove portion: convex portion) is previously arranged. Is done. Laser light emitted from the optical head of the information recording / reproducing apparatus is guided along the information row by the recording track. The recording track has a concave shape and a convex shape alternately arranged. When viewed from the optical head, a concave shape, that is, a far side is referred to as a land portion, and conversely, a convex shape, that is, a near side is referred to as a groove portion. The distance from the center of the land portion or groove portion to the center of the adjacent land portion or groove portion is called a track pitch.
[0008]
  In order to form a phase change optical disk medium using a recording film and a substrate as described above, a first dielectric layer, a recording film, and a second dielectric layer are sequentially disposed on a transparent disk substrate. Or a first dielectric layer, a recording film, a second dielectric layer, and a reflective film are prepared on the transparent disk substrate, or the first dielectric layer, the first dielectric layer, In general, the second dielectric layer, the recording film, the third dielectric layer, the reflective film, and the like are sequentially disposed.
[0009]
  Further, in the layer change type optical disk medium as described above, information is recorded on and reproduced from the recording film by the incidence of laser light from the transparent disk substrate side.
[0010]
  With the recent demand for higher recording density, information is recorded on both the track pitch of the recording track and the concave portion (land portion) of the guide groove and the convex portion (groove portion) between the land portions. Land / groove recording for recording is becoming common. Further, in order to improve the recording density, the spot diameter of the laser beam is being miniaturized.
[0011]
  Since the spot diameter of the laser beam depends on λ / NA of the recording / reproducing diameter (λ: wavelength of the laser beam, NA: numerical aperture of the objective lens), the wavelength of the laser beam is shortened and the numerical aperture of the objective lens is reduced. By increasing the size, the spot diameter of the laser beam is reduced, and the recording density can be increased.
[0012]
  However, as described above, when the numerical aperture of the objective lens is increased, coma aberration increases, and there is a concern that the signal quality is deteriorated. The coma aberration is an amount proportional to the product of the skew angle (tilt angle with respect to the optical axis of the disk), the thickness of the transparent substrate through which the laser light passes, and the third power of the numerical aperture of the objective lens. Therefore, a method for reducing the thickness of the transparent substrate through which the laser beam passes has been proposed as one means for suppressing coma.
[0013]
  As a method for reducing the thickness of the transparent substrate, a light reflection layer, a recording layer, and a thin light transmission layer are sequentially formed on the transparent substrate, and laser light is incident from the thin light transmission layer side to the recording layer. On the other hand, methods for recording and reproducing signals have been proposed. This method is different from the above-described method, which has been widely used in the past, in which the laser beam is incident from the transparent substrate side and the signal is recorded and reproduced.
[0014]
  As a method for forming the light transmission layer described above, a light reflection layer and a recording layer are sequentially formed on a transparent substrate, and then a resin sheet having a thickness of about 100 μm is pasted through an adhesive layer having a thickness of several μm. There are known a method of applying a thin film, a method of forming a thin light-transmitting film, etc. by applying an ultraviolet ray curable resin onto a recording layer and then spreading the ultraviolet curable resin and then irradiating the ultraviolet ray to cure the ultraviolet curable resin.
[0015]
  On the other hand, as described above, a layer change recording medium in which a light reflection layer and a recording layer (including a dielectric layer and a phase change recording layer) are sequentially formed on a transparent substrate and then a thin light transmission layer as described above is formed. Is known to cause a problem that a large noise component is included in a reproduction signal when a signal is recorded and reproduced. When the noise component increases, the reproduced signal deteriorates and the recorded signal cannot be reproduced stably, which hinders improvement in recording density. This large noise component is transferred to the light reflecting layer on which the micro roughness of the substrate surface before deposition of the light reflecting layer and the micro organic matter adhering to the substrate surface are laminated, and as a result, the surface of the light reflecting layer is transferred. This occurs when the film is partially peeled off and the adhesion of the light reflecting layer to the hand substrate is weakened due to the influence of micro organic substances.
[0016]
  Japanese Patent Laid-Open No. 10-36536 discloses a method of irradiating ultraviolet rays using a low-pressure mercury lamp in the atmosphere before forming the light reflection layer in order to suppress the noise increase as described above. . The low-pressure mercury lamp mainly generates light having wavelengths of 185 nm and 254 nm, and ultraviolet light having a wavelength of 185 nm is absorbed by oxygen in the atmosphere to generate ozone. When ultraviolet light of 254 nm is absorbed by this ozone, excited oxygen atoms are generated. On the other hand, short wavelength ultraviolet light of 185 nm has strong photon energy and breaks molecular bonds of organic substances attached to the substrate surface. The cleaved molecule reacts with the excited oxygen atom having a very strong oxidizing power to react with carbon dioxide (CO₂) And moisture (H 2 O) or the like and are scattered and removed. Therefore, the cleaning speed of the substrate surface is strongly influenced by the number of excited oxygen atoms described above.
[0017]
  However, depending on the method disclosed in the above publication, a relatively long irradiation time of about 5 to 20 minutes may be used in order to remove the microscopic surface roughness of the substrate surface and the micro organic matter adhering to the substrate surface. In short, it is inferior in mass productivity. Also, with low-pressure mercury with a large area that can process many substrates at once, after all the substrates that can be set on the pallet (usually 8 to 10) have been processed, the substrate is mounted on the pallet. And evacuated. Therefore, in such a method, the substrate processed first is left in the atmosphere for 40 minutes or more after the treatment, and contamination of the substrate surface with organic substances during that time is inevitable. Furthermore, considering the spectral characteristics of the low-pressure mercury lamp described above, ultraviolet light of 185 nm and 254 nm is mainly irradiated, but infrared light having a longer wavelength is also irradiated. For this reason, when irradiation as described above is performed for a relatively long time, there is a problem that the temperature of the substrate rises and the substrate is deformed.
[0018]
[Problems to be solved by the invention]
  Accordingly, an object of the present invention is to produce a low-noise and high-quality optical disk medium that has a flat substrate surface before film formation and always has a constant state.Manufacturing method of optical disk mediumIs to provide.
[0019]
[Means for Solving the Problems]
  A book that solves the problemIn the method of manufacturing an optical disk medium according to the invention, the vacuum ultraviolet light irradiation performed on the optical recording layer forming surface of the substrate in the film formation preliminary exhaust chamber is performed while oxygen gas is introduced into the film formation preliminary exhaust chamber, and then the vacuum ultraviolet light irradiation is performed. The substrate subjected to the above is transferred to a chamber connected to the film forming preliminary exhaust chamber in a vacuum environment, and an optical recording layer is formed on the optical recording layer forming surface of the substrate in the chamber. .
[0019]
By adopting such a configuration, vacuum ultraviolet light irradiation is performed while introducing oxygen gas into the film-formation preliminary exhaust chamber, so that the molecular bonds of organic substances attached to the substrate surface by ultraviolet light irradiation are cut and free radicals are expressed. In contrast, by actively introducing oxygen, CO ₂ And H ₂ Manufactures optical disk media with reduced noise by being scattered and removed as gas such as O be able to. In addition, since the film formation preliminary exhaust chamber and the chamber are connected in a vacuum environment, the substrate irradiated with ultraviolet light is transferred into the chamber without being exposed to the atmosphere, and the substrate surface before film formation is flattened and always constant. It is possible to manufacture a low-noise and high-quality optical disc medium having the above state.
[0020]
The oxygen gas pressure in the film-formation preliminary exhaust chamber can be set to 10 to 5000 Pa, and further, vacuum ultraviolet light irradiation to the optical recording layer forming surface of the substrate is performed by irradiating the ultraviolet light with a plurality of sheets. When processing these substrates, it becomes possible to etch a plurality of substrates uniformly.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, first of the present inventionApplied to optical disk medium manufacturing methodAn optical disk medium manufacturing apparatus will be described with reference to the drawings.
  FIG. 1 illustrates the present invention.Applied to optical disk medium manufacturing methodIt is a figure which shows the cross-sectional block diagram about one Embodiment of an optical disk medium manufacturing apparatus. As shown in FIG. 1, the optical disk medium manufacturing apparatus of the present invention has a pallet 2 that supports an introduced substrate 1 and a single vacuum ultraviolet light having a wavelength of 180 nm or less facing the pallet 2 that supports the substrate 1. A film formation preliminary exhaust chamber 3 including an irradiation device 6 is provided. In the optical disk medium manufacturing apparatus shown in FIG. 1, the pallet 2 is a self-revolving pallet and is rotated by a rotary motor.
  The substrate 1 is preferably a substrate having prepits.
[0022]
  Further, the single vacuum ultraviolet light is irradiated from the lamp 5 included in the single vacuum ultraviolet light irradiation device 6. The wavelength of the vacuum ultraviolet light emitted from the single vacuum ultraviolet light irradiation device provided in the optical disk medium manufacturing apparatus shown in FIG. 1 only needs to be 180 nm or less, for example, a single ultraviolet light having a wavelength of 172 Will be irradiated.
  Although not shown in FIG. 1, the optical disk medium manufacturing apparatus of the present invention includes a chamber for forming at least one thin film, for example, an optical recording layer, on a substrate 1.
[0023]
  The vacuum preliminary exhaust chamber 2 and the chamber are preferably connected in a vacuum environment.
  Since it is configured in this way, the substrate 1 irradiated with ultraviolet light is phased in the chamber without being exposed to the atmosphere, so that the surface of the substrate 1 before film formation is flattened and the noise is always constant. In addition, a high-quality optical disk medium can be manufactured.
[0024]
  The pallet 2 is rotatable, and the single vacuum ultraviolet light irradiation device 6 is disposed so as to be able to irradiate the substrate 1 supported by the pallet 2 with a single vacuum ultraviolet light. In the optical disk medium manufacturing apparatus shown in FIG. 1, the pallet 2 is a self-revolving pallet and is configured to support eight substrates 1 at a time. And the said single vacuum ultraviolet light irradiation apparatus 6 is arrange | positioned so that a single vacuum ultraviolet light can be irradiated to the board | substrate 1 supported by the said pallet 2. As shown in FIG.
[0025]
  The distance between the ultraviolet light emitting surface 7 of the single vacuum ultraviolet light irradiation device 6 and the pallet 2 supporting the substrate 1 is 30 mm or less. By using such a distance, it becomes possible to manufacture an optical disk medium with further reduced noise. The distance is more preferably 1 mm to 30 mm. When this distance exceeds 30 mm, noise may increase rapidly.
[0026]
  In the optical disk medium manufacturing apparatus shown in FIG. 1, the single vacuum ultraviolet light irradiation device 6 is configured to be able to pulse the ultraviolet light 4. Thus, by irradiating the ultraviolet light 4 in a pulsed manner, when processing a plurality of substrates 1, the plurality of substrates 1 can be uniformly etched.
[0027]
  Although not shown in FIG. 1, the optical disk medium manufacturing apparatus of the present invention shown in FIG. 1 includes an oxygen gas introduction unit in the film formation preliminary exhaust chamber 3. By providing such an oxygen gas introduction part, molecular bonds of organic substances attached to the surface of the substrate 1Is cut by irradiation with ultraviolet light, and by actively introducing oxygen to this, CO ₂ And H ₂ O and other gases are scattered and removedIt becomes easy to manufacture an optical disc medium with further reduced noise.
  In addition, it is preferable that the oxygen gas pressure when it introduces into the said film-formation preliminary exhaust chamber 3 from the said oxygen gas introduction part shall be 10-5000Pa.
[0028]
  Next, an embodiment of the optical disk medium manufacturing method of the present invention will be described.
The method for producing an optical disk medium of the present invention can be carried out using the above-described optical disk medium production apparatus. In the manufacturing method of the optical disk medium of the present invention, the surface of the substrate 1 on which the optical recording layer is formed is irradiated with vacuum ultraviolet light in the film formation preliminary exhaust chamber 3, and then the substrate 1 subjected to vacuum ultraviolet light irradiation is not exposed to the atmosphere. And forming an optical recording layer on the optical recording layer forming surface of the substrate.
[0029]
  As the substrate, a substrate made of a material usually used for manufacturing an optical disk medium can be used, and for example, a transparent resin substrate made of polycarbonate can be used. Further, as the optical recording layer, a material usually used for forming an optical recording layer of an optical disk medium can be used, and for example, a material made of an ultraviolet curable resin can be used.
[0030]
  Before the substrate is irradiated with vacuum ultraviolet light, it is preferable that the film formation preliminary exhaust chamber 3 is first evacuated and oxygen gas is introduced. When the vacuum is applied, the degree of vacuum is preferably 1 × 10 −4 Pa to 1 × 10 −3 Pa. The amount of oxygen gas introduced is preferably about 50 SCCM, and the oxygen gas pressure in the film formation preliminary exhaust chamber 3 is preferably 10 to 5000 Pa.
  The organic material adhering to the surface of the substrate 1 is irradiated with vacuum ultraviolet light while introducing oxygen gas.The molecular bond of is broken by irradiation with ultraviolet light, and free radicals are expressed. On the other hand, by actively introducing oxygen, CO ₂ And H ₂ It becomes a gas such as O and it is easy to be scattered and removed.This is because an optical disk medium with further reduced noise is manufactured.
[0031]
  The vacuum ultraviolet light irradiation is preferably performed by pulsed irradiation of ultraviolet light. By performing vacuum ultraviolet light irradiation by irradiating with ultraviolet light, even when processing a plurality of substrates, the plurality of substrates can be uniformly etched.
  In the method for producing an optical disk medium of the present invention, after the substrate is irradiated with vacuum ultraviolet light, the optical recording layer is formed on the optical recording layer forming surface of the substrate without exposing the substrate to the atmosphere. Since the optical recording layer is formed without exposing the substrate irradiated with vacuum ultraviolet light to the atmosphere in this way, the substrate surface is not left in the atmosphere, and the substrate surface is contaminated by organic substances in the atmosphere. There is no. Accordingly, it is possible to produce a low-noise and high-quality optical disk medium that has a flat substrate surface before film formation and always has a constant state.
[0032]
  In the optical disk medium manufacturing method of the present invention, after the optical recording layer is formed, a desired reflective film layer, dielectric layer, phase change recording layer, and the like are sequentially formed as appropriate, and finally the substrate is collected to recover the optical disk. Get the medium. The reflective film layer is, for example, an AlTi alloy, and the dielectric layer is, for example, ZnS · SiO.₂As the layer change layer, for example, Ge₂Sb₂Te₅It can be formed using what consists of.
[0033]
  Next, another embodiment of the method for producing an optical disk medium of the present invention will be described.
  In another embodiment of the method for producing an optical disk medium of the present invention, the substrate on which the optical recording layer forming surface of the substrate is irradiated with vacuum ultraviolet light in the film formation preliminary exhaust chamber and then the substrate subjected to vacuum ultraviolet light irradiation is formed on the film. It is transferred to a chamber connected to the preliminary exhaust chamber in a vacuum environment, and an optical recording layer is formed on the optical recording layer forming surface of the substrate in the chamber.
  This embodiment is different from the above-described embodiment in that a substrate subjected to vacuum ultraviolet light irradiation is transferred to a chamber connected to a film formation preliminary exhaust chamber in a vacuum environment, and the optical recording of the substrate is performed in the chamber. The difference is that an optical recording layer is formed on the layer forming surface. About another point, it is the same as that of embodiment mentioned above.
[0034]
  In this embodiment, the substrate that has been subjected to vacuum ultraviolet light irradiation is transferred to a chamber connected to the deposition preliminary exhaust chamber in a vacuum environment, and light is applied to the optical recording layer forming surface of the substrate in the chamber. Since the recording layer is formed, the optical recording layer is formed without exposing the substrate irradiated with vacuum ultraviolet light to the atmosphere, so that the substrate is not left in the atmosphere, and the surface of the substrate is caused by organic substances in the atmosphere. Will not be contaminated.
[0035]
【Example】
  Hereinafter, the present invention will be described in more detail with reference to examples. Needless to say, the scope of the present invention is not limited to such examples.
  Example 1
  An optical disk medium was manufactured using an optical disk medium manufacturing apparatus as shown in FIG. Wavelength 172 nm (irradiance 7 mW / cm) using a dielectric barrier discharge excimer lamp with 8 transparent resin substrates set on a self-revolving pallet and filled with Xe gas²) Was applied to the eight substrates.
[0036]
  First, in the optical disk medium manufacturing apparatus shown in FIG. 1, eight transparent resin substrates 1 (thickness 0.6 mm, diameter 120 mm) on which guide grooves for guiding laser light are formed are supported on a self-revolving pallet 2; The self-revolving pallet 2 was introduced into the preliminary exhaust chamber 3. Then, the inside of the preliminary exhaust chamber 3 is 1 × 10^-4~ 1x10^-3After preliminary evacuation to a pressure of Pa, 50 SCCM of oxygen gas was introduced while rotating the self-revolving pallet 2 to bring the oxygen gas pressure to 100 Pa. Next, the substrate was irradiated with single ultraviolet light 4 having a wavelength of 172 nm for 30 seconds.
[0037]
  Next, the self-revolving pallet 2 supporting the substrate irradiated with single ultraviolet light was transferred to an in-line sputtering apparatus, which is the next chamber connected in a vacuum environment.
  FIG. 2 shows a cross-sectional view of the optical disk medium manufactured in this embodiment. Description will be made sequentially with reference to FIG.
[0038]
  First, using an AlTi alloy target containing 2% by mass of Ti on the substrate 1, the distance between the target and the substrate is 15 cm in an argon gas atmosphere, and the power density is 1.6 W / cm.²The reflective film layer 11 having a thickness of 100 nm was formed at a gas pressure of 0.08 Pa.
  Next, ZnS · SiO₂Using the target, the power density is 2.2 W / cm with a distance of 15 cm between the target and the substrate in an argon gas atmosphere.²The first dielectric layer 12 having a thickness of 35 nm was formed at a gas pressure of 0.1 Pa.
[0039]
  Then Ge₂Sb₂Te₅Using the target, the power density is 0.27 W / cm at a distance of 15 cm between the target and the substrate in an argon gas atmosphere.²The phase change recording layer 13 having a thickness of 15 nm was formed at a gas pressure of 1.0 Pa.
  Next, ZnS · SiO₂Using the target, the power density is 2.2 W / cm with a distance of 15 cm between the target and the substrate in an argon gas atmosphere.²The second dielectric layer 14 having a thickness of 130 nm was formed at a gas pressure of 0.1 Pa.
[0040]
  The film formation time for each layer was adjusted to a desired thickness as appropriate. After forming the second dielectric layer 14, an ultraviolet curable resin is applied and spread on the second dielectric layer 14, and the ultraviolet curable resin is cured by irradiating with ultraviolet rays to form a light transmission layer having a thickness of 100 μm. 15 was formed to obtain an optical disk medium. In addition, the application amount and development time of the ultraviolet curable resin used here were adjusted so as to have a desired film thickness as appropriate. In the cross-sectional view of the optical disk medium shown in FIG. 2, the vacuum ultraviolet light irradiation surface 10 is shown. In practice, the thickness of the vacuum ultraviolet light irradiation surface 10 cannot be measured, but in FIG. Conceptually, the surface exposed to vacuum ultraviolet light is shown.
[0041]
  Test example 1
  After the substrate was irradiated with single vacuum ultraviolet light, the substrate was once exposed to the atmosphere and left in the atmosphere for 60 minutes. When the contact angle of water, which is an index of wettability, was measured on a substrate immediately after exposure to the atmosphere and a substrate left in the atmosphere for 60 minutes, the contact angle of water on the substrate immediately after exposure to the atmosphere was about 5 degrees. On the other hand, the contact angle of water after being left in the atmosphere for 60 minutes was about 15 degrees. Therefore, it can be seen that it is not preferable to expose the substrate once irradiated with a single ultraviolet light to the atmosphere or leave it for a long time after being irradiated in the atmosphere. In the following examples, the following film forming process is performed without lowering the degree of vacuum on the substrate subjected to the single ultraviolet light irradiation.
[0042]
  Example 2
  An optical disk medium is prepared by performing the same operation as in Example 1 while changing the distance d between the light emitting surface of the single ultraviolet light irradiation device and the outermost surface of the transparent resin substrate 1 within a range of 1 to 50 mm. The medium noise was measured for the optical disk medium. FIG. 3 is a graph showing the relationship between the distance d between the light emitting surface and the outermost surface of the transparent resin substrate and the medium noise level. As shown in FIG. 3, it can be seen that the medium noise level slightly increases with an increase in irradiation distance when the distance is between 1 and 30 mm, but rapidly increases when the distance exceeds 30 mm. FIG. 3 also shows the noise level of the medium not irradiated with ultraviolet light.
[0043]
  As shown in FIG. 3, when the distance is 50 mm, the noise level is the same as that of the medium not irradiated with vacuum ultraviolet light. This is because when the distance between the single vacuum ultraviolet light emitting surface and the substrate surface is increased, the ultraviolet light is absorbed by oxygen atoms before reaching the substrate surface, the energy is reduced, and the substrate surface is attached. This is due to the loss of the etching ability of the substrate surface because the molecular bonds of the organic substance are not cut. Therefore, the distance between the single ultraviolet light emitting surface and the outermost surface of the transparent resin substrate is preferably 30 mm or less.
[0044]
  Example 3
  The oxygen gas pressure in the vacuum pre-exhaust chamber is 1 Pa to 1 × 10⁴The optical disk medium was manufactured by changing the pressure between Pa and irradiating the substrate with vacuum ultraviolet light, and then performing the same operation as in Example 1. The distance between the vacuum ultraviolet light emitting surface and the outermost surface of the substrate was fixed at 5 mm. Medium noise was measured for the obtained optical disk medium.
[0045]
  FIG. 4 is a graph showing the relationship between the oxygen gas pressure in the vacuum preliminary exhaust chamber and the noise level of the optical disk medium. As shown in FIG. 4, the oxygen gas pressure in the vacuum preliminary exhaust chamber is 10 Pa to 5 × 10 6.³In the range of Pa, the media noise was relatively low, but in other ranges, the media noise tended to increase. The reason why the noise is high at 1 Pa is that the amount of excited oxygen atoms generated is small because the amount of oxygen absorbed by vacuum ultraviolet light is small, and therefore the etching ability of the substrate surface is lowered. Meanwhile, 1 × 10⁴In Pa, oxygen atoms are excessive due to the low vacuum, and the ultraviolet light is absorbed by the oxygen atoms before reaching the substrate surface, the energy of the ultraviolet light is reduced, and the molecular bonds of the organic substances attached to the substrate surface are reduced. Cutting is not actively performed, the etching ability of the substrate surface is lost, and noise increases. Therefore, the degree of vacuum in the vacuum pre-evacuation chamber when irradiating with vacuum ultraviolet light is 10 to 5 × 10.³Pa is preferred.
[0046]
  In addition, no warpage or deformation was observed in any of the optical disk media manufactured by the above-described method.
[0047]
  In the above embodiment, the irradiation with vacuum ultraviolet light was performed by continuous light irradiation. However, depending on the balance between the rotation speed of the revolving pallet and the irradiation time, it is possible to uniformly irradiate a large number of substrates with ultraviolet light. May be difficult. In such a case, a relatively long irradiation time may be set, and pulse irradiation may be performed to uniformly etch a plurality of substrates. Similar effects were obtained when pulsed irradiation was performed.
[0048]
  In the above embodiment, the dielectric barrier discharge excimer lamp in which Xe gas is sealed is used to irradiate single vacuum ultraviolet light having a wavelength of 172 nm, but the wavelength is 126 nm using Ar as the sealing gas, or Kr. Similar effects were obtained when single vacuum ultraviolet light having a wavelength of 146 nm using a gas was irradiated. Further, the irradiation illuminance of the vacuum ultraviolet light is not limited to the above-described one, and an optimal irradiation illuminance may be appropriately selected depending on the balance of film formation tact and the like.
[0049]
  In the above-described embodiments, the recording film, the reflective film, the dielectric layer material and the number of layers, and the method of forming each film are not limited to those described above, and are appropriately selected according to the desired recording / reproduction characteristics and application. Is done. In addition, the effect does not change depending on the film forming method and material of each film, the number of layers, and the like. Further, the material and thickness of the substrate are not limited to those described above, and may be appropriately selected. Moreover, although the ultraviolet curable resin was used as the light transmission layer 15 in the said Example, the same effect was acquired even if it used the PC film whose thickness is 100 micrometers, for example.
[0050]
【The invention's effect】
  As detailed above,Of the present inventionAccording to the optical disc manufacturing method, the substrate surface before film formation is flattened,Moreover, the organic matter whose molecular bond is broken by ultraviolet light irradiation is easily removed,A low-noise and high-quality optical disk medium that always has a constant state can be manufactured.
[Brief description of the drawings]
FIG. 1 of the present inventionApplied to optical disk medium manufacturing methodIt is a figure which shows the cross-sectional block diagram about one Embodiment of an optical disk medium manufacturing apparatus.
FIG. 2 is a cross-sectional view of an optical disk medium manufactured in this example.
FIG. 3 is a graph showing the relationship between the distance d between the light emitting surface and the outermost surface of the transparent resin substrate and the medium noise level.
FIG. 4 is a graph showing the relationship between the oxygen gas pressure in the vacuum preliminary exhaust chamber and the noise level of the optical disk medium.
[Explanation of symbols]
1 Substrate
2 Palette
3 Vacuum preliminary exhaust chamber
4 Vacuum ultraviolet light
5 lamps
6 Vacuum ultraviolet light irradiation equipment
7 Ultraviolet light emitting surface
8 Rotating motor

Claims (3)

Vacuum ultraviolet light irradiation performed on the optical recording layer forming surface of the substrate in the film formation preliminary exhaust chamber is performed while introducing oxygen gas into the film formation preliminary exhaust chamber, and then the substrate subjected to vacuum ultraviolet light irradiation is formed on the film. A method for producing an optical disk medium, comprising: transferring to a chamber connected to a preliminary exhaust chamber in a vacuum environment, and forming an optical recording layer on the optical recording layer forming surface of the substrate in the chamber. The method for producing an optical disk medium according to claim 1, wherein an oxygen gas pressure in the deposition preliminary exhaust chamber is 10 to 5000 Pa. 3. The method of manufacturing an optical disk medium according to claim 2, wherein the irradiation with vacuum ultraviolet light on the optical recording layer forming surface of the substrate is performed by pulse irradiation with ultraviolet light.

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