JP4434873B2 - Optical recording medium manufacturing apparatus and manufacturing method - Google Patents

Description

  The present invention relates to a manufacturing apparatus and a manufacturing method for an optical recording medium such as an optical disk.

  High-density recording of the optical recording medium can be achieved by shortening the wavelength of the laser light used in the optical pickup, increasing the numerical aperture (NA) of the objective lens, and reducing the size of the focused spot UV.

  For example, a CD (Compact Disc) has a laser beam wavelength of 780 nm, a numerical aperture (NA) of 0.45, and a recording capacity of 650 MB (megabytes). In a DVD-ROM (Digital Versatile Disc-ROM), the laser beam wavelength is 650 nm, the numerical aperture (NA) is 0.6, and the recording capacity is 4.7 GB (gigabytes). ing. Further, in the next-generation disc-shaped optical recording medium (so-called Blu-ray Disc (trade name), hereinafter abbreviated as BD disc as appropriate), light transmission of about 100 μm (0.1 mm) on the signal reading surface side of the disc. By forming a protective film with a laser beam wavelength of 450 nm or less and NA of 0.78 or more, it is possible to increase the capacity of 22 GB or more with a single layer.

  In CD and DVD, the dimension from the signal reading surface (disk surface) of the disk to the reflective film on which the signal is recorded is relatively large. That is, it is about 1.2 mm for CD and about 0.6 mm for DVD. On the other hand, in a BD disc, this dimension is about 0.1 mm. When a single-sided dual-layer optical disc is formed, the intermediate layer formed between the two optical recording layers needs to be thinned to about 20 μm to 30 μm. A high thickness accuracy is required for the light-transmitting layers such as the protective film and the intermediate layer.

  As an example of a method for forming a film-like layer such as a protective film and an intermediate layer on a substrate, a spin coating method is known. For example, in the formation of the light transmission layer, a resin material such as a light transmissive ultraviolet curable resin is dropped on the disk substrate, and the dropped resin material is spread evenly on the entire surface of the disk substrate with a spin coater. A curing method is generally used.

  Patent Document 1 listed below describes a protective film forming apparatus and a protective film forming method for forming a protective film with a predetermined film thickness and forming a protective film with a uniform film thickness over the entire substrate. .

JP-A-10-249264

  Furthermore, in order to suppress fluctuations in film thickness for each disk substrate coated with a resin material by the spin coating method and maintain a stable film thickness accuracy, it is necessary to suppress changes in the viscosity of the resin material. It is necessary to keep the temperature of the material constant. Therefore, the temperature in the manufacturing apparatus and the temperature of the resin material dripped onto the disk substrate are kept constant.

  In a BD disc, very strict specifications are imposed on the film thickness accuracy of the light transmission layer, and it is not always sufficient to control the temperature in the manufacturing apparatus and the temperature of the resin material dripped onto the substrate. Therefore, it is necessary to control not only these controls but also the temperature of the substrate on which the resin material is applied. However, conventionally, the substrate immediately after molding is cooled, but the temperature of the substrate immediately before forming a thin film by spin coating has not been adjusted. Conventionally, a cooling stage has been used to cool the substrate. However, since it takes time to lower the temperature of the substrate, the size of the cooling stage is large. As a result, there is a problem that the manufacturing apparatus becomes large and disadvantageous in terms of cost.

  In addition, the conventional method has a disadvantage that the substrate temperature can be controlled only to a temperature substantially equal to the temperature in the manufacturing apparatus, and the substrate temperature cannot be controlled to an optimum value, and the film thickness can be reduced. There was a limit to improving accuracy.

  Accordingly, an object of the present invention is to provide an optical recording medium that can adjust the temperature of a substrate immediately before forming a thin film by spin coating without taking up space in a short time and improve the film thickness accuracy of the thin film formed on the substrate. It is in providing a manufacturing apparatus and a manufacturing method.

In order to achieve the above object, a first invention provides an optical recording medium manufacturing apparatus having an information signal layer and a thin film formed by spin coating on a main surface of a substrate, wherein the thin film is formed on the main surface by spin coating. a plurality of fixing a table board immediately before is placed but is formed, is provided with the mounting surface of the table so as to open at equal intervals on each circle of the concentric circles, the substrate table by adsorption And a temperature adjusting means for adjusting the temperature of the substrate placed on the table by controlling the temperature of the table by causing the temperature-adjusted refrigerant to flow through the refrigerant flow path provided in the table. An optical recording medium manufacturing apparatus characterized by the above.

According to a second aspect of the present invention, there is provided a method of manufacturing an optical recording medium having an information signal layer and a thin film formed by spin coating on a main surface of a substrate, immediately before the thin film is formed on the main surface by spin coating. and placing the substrate on the table, it is provided with the mounting surface of the table so as to open at equal intervals on each circle of the concentric circles, a substrate with a plurality of suction openings for fixing the substrate on the table by suction An optical recording medium characterized in that the temperature of the substrate placed on the table is adjusted by controlling the temperature of the table by allowing the fixed and temperature-controlled refrigerant to flow through the refrigerant flow path provided in the table. It is a manufacturing method.

  According to the optical recording medium manufacturing apparatus and manufacturing method of the present invention, the substrate is placed on the table and the temperature of the table is controlled immediately before the thin film is formed on the main surface of the substrate by spin coating. By adjusting the temperature, it is possible to form a thin film on a substrate by spin coating at a substrate temperature optimum for forming the thin film by spin coating. Thus, when a thin film such as a light transmission layer of an optical recording medium is formed on the main surface of the substrate with a resin material such as an ultraviolet curable resin, the film thickness distribution of the formed thin film can be maintained with high accuracy and manufactured. Variation in film thickness for each optical recording medium is reduced. As a result, even with a very strict film thickness standard, the yield does not deteriorate and stable mass production of optical recording media is possible.

  Hereinafter, an embodiment of the present invention will be described using a read-only optical disk as an example. Optical discs that form thin-film light-transmitting layers such as protective films and intermediate layers by spin coating are in-line optical discs that perform a series of processes from substrate molding, reflective film formation, and light-transmitting layer formation in a flow process Manufactured with manufacturing equipment.

  In the substrate molding process, the disk substrate on which the signal is transferred is molded by injection molding or the like. In the reflection film adding step, a reflection film is added by sputtering or the like on the signal transfer surface of the disk substrate formed in the substrate forming step. In the light transmission layer forming step, a light transmission layer is formed by spin coating on the signal transfer surface of the disk substrate to which the reflection film has been added in the reflection film addition step.

  Since the disk substrate immediately after being formed by the substrate forming step is usually at a high temperature of about 70 ° C. to 100 ° C., a cooling step using a cooling stage is usually provided between the substrate forming step and the reflective film adding step. The cooling stage is a stage that cools the disk substrate by bringing the disk substrate into contact with air. By providing the cooling step, the disk substrate after molding can be sufficiently cooled, and the temperature of the disk substrate can be made substantially the same as the temperature in the optical disk manufacturing apparatus.

  Conventionally, since the film thickness accuracy required for the light transmission layer formed on the disk substrate was not so strict, there was no problem simply by providing a cooling step between the substrate forming step and the reflective film adding step. However, when manufacturing an optical disc for high-density recording in which the film thickness accuracy of the light transmission layer is stipulated very strictly, the spin coating method is used in the light transmission layer forming process in order to satisfy the specified film thickness accuracy. Thus, the inventors of the present application have found that the temperature of the disk substrate immediately before forming the light transmission layer is important.

  Since the temperature of the disk substrate rises even after processing in the reflective film adding step, in the conventional optical disk manufacturing apparatus, for example, when the manufacturing cycle is disturbed due to an apparatus trouble or the like, the temperature of the disk substrate immediately before forming the light transmission layer is increased. It was not always constant. Therefore, an optical disk manufacturing apparatus according to an embodiment includes a temperature control table device for adjusting the temperature of a disk substrate immediately before forming a thin film that requires a high thickness accuracy such as a light transmission layer in a spin coater.

  FIG. 1 is an example of a configuration of a temperature control table device included in an optical disk manufacturing apparatus according to an embodiment of the present invention. Reference numeral 1 denotes a disk substrate whose temperature is adjusted by a temperature control table device.

  The table 2 has a mounting surface on which the disk substrate 1 is mounted, and is formed of, for example, a metal material having good thermal conductivity such as aluminum, copper, or an alloy containing them. By forming the table 2 with a material having high thermal conductivity, the temperature of the disk substrate 1 placed on the table 2 can be adjusted in a short time.

  The table 2 includes two members: an upper table (hereinafter referred to as an upper plate) 3 on which the disk substrate 1 is placed, and a lower table (hereinafter referred to as a lower plate) 4 positioned on the lower side thereof. Has been. The upper plate 3 and the lower plate 4 may be formed of different materials. The table 2 may be constituted by a single member in which the upper plate 3 and the lower plate 4 are integrated. The mounting surface of the disk substrate 1 provided on the upper plate 3 may be configured to contact the entire main surface of the disk substrate 1 so that the temperature distribution on the entire surface of the mounted disk substrate 1 is uniform. preferable.

  The table 2 has a center pin 5 and a hole 6 for fixing the disk substrate 1 to the mounting surface of the upper plate 3. The center pin 5 protrudes on the mounting surface of the disk substrate 1 and positions the disk substrate 1 to be mounted by fitting a center hole of the disk substrate 1. In this example, the center pin 5 is composed of one member integrated with the upper plate 3, but the center pin 5 is composed of a member different from the upper plate 3, and the mounting surface of the disk substrate 1 is used as a cap. It is good also as detachable with respect to.

  The holes 6 are for adsorbing the main surface of the disk substrate 1 to the mounting surface of the upper plate 3. The hole 6 communicates with one end of a vacuum channel 7 provided in the upper plate 3 and the lower plate 4. The other end of the vacuum channel 7 is connected to a vacuum source outside the table 2 (not shown).

  For example, a plurality of holes 6 are provided uniformly on the mounting surface of the upper plate 3 so as to uniformly adsorb the main surface of the disk substrate 1. In this example, a plurality of holes 6 are concentrically arranged at equal intervals on the inner and outer circumferences of the placement surface of the upper plate 3 so as to be located on the inner circumference side and the outer circumference side of the disc substrate 1 to be placed. Is provided. The suction port for sucking the disk substrate 1 to the mounting surface of the upper plate 3 is not limited to the hole 6 and may be provided by a groove. These suction ports are preferably provided as small as possible within a range in which the suction state of the disk substrate 1 can be maintained so that the temperature distribution on the entire surface of the disk substrate 1 placed on the upper plate 3 is uniform.

  The disk substrate 1 placed on the upper plate 3 is positioned by the center pin 5 and fixed in close contact with the placement surface of the upper plate 3 by a vacuum source (not shown) connected through the hole 6 and the vacuum channel 7. Is done.

  The fixing of the disk substrate 1 to the mounting surface of the upper plate 3 is not limited to these. For example, the positioning of the disk substrate 1 on the mounting surface of the upper plate 3 may be configured such that the outer periphery of the disk substrate 1 is regulated. The disk substrate 1 is closely attached to the mounting surface of the upper plate 3 by blowing air from the upper side of the mounted disk substrate 1 or by moving the disk substrate 1 mounted by a pressing member such as a cap or a holder upward. Or may be pressed from

  The surface roughness of the mounting surface of the upper plate 3 may be finished to 0.8 S or less so that the main surface of the disk substrate 1 is not damaged when the disk substrate 1 is attracted to the upper plate 3. preferable. Here, the unit S represents an average interval (JIS B0601) between local peaks defined in the Japan Industrial Standard (JIS).

  The table 2 is provided with a refrigerant flow path 8 to which a refrigerant, for example, water, which is controlled to a predetermined temperature is supplied from a temperature controller (hereinafter referred to as a temperature controller) outside the table 2 (not shown). . In addition, the refrigerant | coolant supplied to the refrigerant | coolant flow path 8 is not specifically limited, As long as the temperature of the table 2 can be controlled appropriately, other media, such as oil, may be sufficient.

  The temperature of the table 2 can be controlled by controlling the temperature of the refrigerant flowing through the refrigerant flow path 8. The refrigerant flow path 8 is formed, for example, by providing a groove on a surface in contact with the lower plate 4 of the upper plate 3. The upper plate 3 and the lower plate 4 are sealed with bolts (not shown) so that the outer periphery of the refrigerant flow path 8 is sealed by a sealing member such as an O-ring (not shown) so that the refrigerant does not leak from the refrigerant flow path 8 to the outside. It is fixed with a member.

  The table 2 configured as described above controls the temperature of the table 2 by controlling the temperature of the refrigerant flowing through the refrigerant flow path 8, and adjusts the temperature of the disk substrate 1 placed on the table 2. Can do.

  When temperature-controlled air is blown onto the disk substrate 1 to adjust the temperature of the disk substrate 1, there is a problem that the temperature in the manufacturing apparatus also changes. By adjusting, the temperature of the disk substrate 1 can be adjusted without changing the temperature in the manufacturing apparatus. Further, when the temperature of the disk substrate 1 is adjusted by the cooling stage, it takes time to adjust the temperature of the disk substrate 1, and not only the manufacturing apparatus becomes large, but also the temperature of the disk substrate 1 can only be the same as that in the manufacturing apparatus. Although the temperature cannot be controlled, the temperature of the disk substrate 1 can be adjusted to a temperature different from the temperature in the manufacturing apparatus by adjusting the temperature of the disk substrate 1 with this temperature control table device.

  This temperature control table device uses a member having a heat conductivity much higher than that of air, such as aluminum, as a heat transfer medium. Therefore, when temperature-controlled air is blown onto the disk substrate 1 or a cooling stage is used. Compared to the air cooling system such as the above, the heat of the disk substrate 1 can be absorbed quickly or the heat can be absorbed quickly by the disk substrate 1. Therefore, the temperature of the disk substrate 1 can be made substantially equal to the temperature of the table 2 in a short time.

  An optical disk manufacturing apparatus according to an embodiment includes a spin coater that forms a thin film that requires high film thickness accuracy, such as a light transmission layer, on a main surface of a disk substrate 1 by a spin coat method. In addition, the optical disc manufacturing apparatus according to one embodiment has one or more temperature control table devices at positions close to the spin coater. For example, an appropriate number of temperature control table devices is provided according to the takt time of the optical disk manufacturing apparatus, the target temperature of the disk substrate 1, and the like. In the case where a plurality of temperature control table devices are provided, for example, the refrigerant flow path 8 and the vacuum flow path 7 provided in each table 2 are respectively connected, and the temperature controller and the vacuum flow connected to the refrigerant flow path 8 are connected. A common vacuum source connected to the path 7 may be used.

  Immediately before supplying the disk substrate 1 to the spin coater, the temperature of the disk substrate 1 is adjusted by the temperature control table device. That is, the disk substrate 1 whose temperature has been adjusted by the temperature control table device is immediately supplied to the spin coater by the transfer arm or the like and processed. When the optical disk manufacturing apparatus has a plurality of temperature control table devices, for example, the temperature of the disk substrate 1 is adjusted in series by each temperature control table device, and then the temperature-controlled disk substrate 1 is spin-coated. Supply the equipment immediately.

  With reference to FIG. 2, an example of forming a thin film by a spin coating method will be described. When forming a thin film on the disk substrate 1 by the spin coating method, first, as shown in FIG. 2A, the disk substrate 1 is placed on the spin tray 11 of the spin coating apparatus. Next, the center cap 12 is attached to the center hole of the disk substrate 1 to close the center hole of the disk substrate 1. In this example, the center cap 12 is attached to the thin film forming surface side of the disk substrate 1 using the upper part of the center hole, and the lower part of the center hole is fitted to the protruding portion of the spin tray 11 so that the disk is placed on the spin tray 11. The substrate 1 is fixed. The disk substrate 1 and the center cap 12 are adsorbed and fixed to the placement surface side of the spin tray 11 by vacuum channels 13 and 14 connected to a vacuum source (not shown).

  When the disk substrate 1 is fixed to the spin tray 11 and the center cap 12 is attached to the center hole of the disk substrate 1, a resin such as an ultraviolet curable resin for forming a thin film on the center cap 12, as shown in FIG. Material 15 is applied (dropped). After the application of the resin material 15, the spin tray 11 is rotated at a high speed of, for example, 3000 to 3500 rpm, and the resin material 15 applied on the center cap 12 is stretched. As a result, a thin film of the resin material 15 is formed on the disk substrate 1 as shown in FIG. 2C. These operations are repeated when spin coating is repeated to increase the film thickness.

  When a thin film of the resin material 15 having a desired thickness is formed on the disk substrate 1, the resin material 15 formed on the disk substrate 1 is cured. For example, when the resin material 15 is an ultraviolet curable resin, ultraviolet rays are irradiated. As a result, a thin film is formed on the disk substrate 1.

  Here, an example of an optical recording medium on which a thin film is formed by spin coating will be described. FIG. 3 is an enlarged cross-sectional view showing an example of the configuration of a single-layer optical disc. The optical disk 21 is configured by sequentially laminating a reflective film 23 and a light transmission layer 24 on one main surface of a disk substrate 22.

  The disk substrate 22 is made of a resin material such as polycarbonate. The reflection film 23 is irradiated with the laser beam condensed by the lens 25 having a high numerical aperture (NA). For example, the lens 25 has a configuration in which two lenses are bonded together, and the NA is 0.85.

  The optical disk 21 has a substantially disk shape with a center hole (not shown) opened at the center. As an example, the disk diameter is 120 mm, the center hole diameter is 15 mm, and the disk thickness is 1.2 mm. The thickness of the disk substrate 22 is 1.1 mm, for example, and the thickness of the light transmission layer 24 is 0.1 mm, for example.

  On one main surface of the disk substrate 22, a reflective film 23 is formed, and an optical recording layer is formed. For the reflective film 23, for example, a film material made of aluminum, silver, gold, or an alloy containing these is used. The optical recording layer made of the reflective film 23 is formed with a pit pattern having a fine uneven shape. The pit has a pit length modulated according to the recording data.

  On the reflective film 23, a light transmission layer 24 is formed as a protective film. The light transmission layer 24 is formed of a resin material such as an ultraviolet curable resin having light transmittance, for example.

  Laser light that passes through the lens 25 is applied to the reflective film 23 of the optical disc 21 from the light transmission layer 24 side. The distance of the lens 25 from the optical disk 21 is adjusted to focus on the reflective film 23, and the return light reflected by the reflective film 23 is received by the light receiving element, and reproduction is performed.

  The optical disk 21 is manufactured, for example, by an in-line apparatus that performs a single process from the formation of the disk substrate 22, the formation of the reflective film 23, and the formation of the light transmission layer 24 by a flow operation. By providing the above-described temperature control table device in the in-line device for manufacturing the optical disc 21, and adjusting the temperature of the disk substrate 22 with the temperature control table device immediately before forming the light transmission layer 24 with a spin coat device, for example, Variation in film thickness every formation can be reduced, and the light transmission layer 24 with a highly accurate film thickness distribution can be formed.

  Although the optical disk 21 has a single-layer structure, the present invention can be applied to the manufacture of an optical disk having a multilayer structure. FIG. 4 is an enlarged cross-sectional view showing an example of the configuration of a multi-layered optical disk. The optical disc 31 is configured by sequentially laminating a reflective film 33, a light transmissive layer 36, a semi-transmissive reflective film 37, and a light transmissive layer 34 on a disk substrate 32.

  The disk substrate 32 is made of a resin material such as polycarbonate. The laser light collected by the lens 35 having a high numerical aperture (NA) is applied to the reflective film 33 or the semi-transmissive reflective film 37. For example, the lens 35 has a configuration in which two lenses are bonded together, and the NA is 0.85.

  The optical disc 31 has a substantially disk shape with a center hole (not shown) opened at the center. As an example, the disk diameter is 120 mm, the center hole diameter is 15 mm, and the disk thickness is 1.2 mm. The thickness of the disk substrate 32 is 1.1 mm, for example, the thickness of the light transmission layer 36 is 25 μm, for example, and the thickness of the light transmission layer 34 is 75 μm, for example.

  On one main surface of the disk substrate 32, a reflective film 33 is formed, and a first optical recording layer (L0 layer) is formed. For the reflective film 33, for example, a film material made of aluminum, silver, gold, or an alloy containing these is used. The optical recording layer formed of the reflective film 33 is formed with a pit pattern having a fine uneven shape. The pit has a pit length modulated according to the recording data.

  On the reflection film 33, a light transmission layer 36 is formed as an intermediate layer. The light transmission layer 36 is formed of a resin material such as an ultraviolet curable resin having light transmittance, for example.

  A transflective film 37 is formed on the light transmission layer 36, and a second optical recording layer (L1 layer) is formed. For the transflective film 37, for example, a film material made of silver or a silver alloy is used. The optical recording layer made of the semi-transmissive reflective film 37 has a pit pattern having a fine uneven shape. The pit has a pit length modulated according to the recording data.

  On the transflective film 37, a light transmission layer 34 is formed as a protective film. The light transmissive layer 34 is formed of a resin material such as an ultraviolet curable resin having light transmittance, for example.

  Laser light through the lens 35 is irradiated from the light transmission layer 34 side to the reflective film 33 or the semi-transmissive reflective film 37 of the optical disk 31. The distance of the lens 35 from the optical disk 31 is adjusted to focus on one of the reflective film 33 and the semi-transmissive reflective film 37, and reproduction is performed on one of the reflective film 33 or the semi-transmissive reflective film 37. The semi-transmissive reflective film 37 is semi-transmissive, and the reflective film 33 is irradiated with laser light through the semi-transmissive reflective film 37 and the light transmissive layer 36. The return light reflected by one recording layer on which the reflective film 33 and the semi-transmissive reflective film 37 are focused is received by the light receiving element, and reproduction is performed.

  For the optical disk 31, for example, a single process from the formation of the disk substrate 32, the formation of the reflection film 33, the formation of the light transmission layer 36, the formation of the semi-transmission reflection film 37, and the formation of the light transmission layer 34 is performed by a flow work. Manufactured with in-line equipment. The in-line device for manufacturing the optical disc 31 is provided with the temperature control table device described above. For example, immediately before the light transmission layer 34 and the light transmission layer 36 are formed by a spin coater, the temperature of the disk substrate 32 is controlled. By adjusting at, the variation in film thickness for each formation is reduced, and the light transmission layer 34 and the light transmission layer 36 with a highly accurate film thickness distribution can be formed.

  The inventor of the present application actually manufactured the single-layer optical disk 21 by controlling the temperature of the refrigerant flowing through the refrigerant flow path 8 of the temperature control table device. The results will be described below. As an optical disk manufacturing apparatus, an in-line apparatus that uses a flow process to perform a single process from the formation of the disk substrate 22, the formation of the reflective film 23, and the formation of the light transmission layer 24 was used.

  The manufactured optical disk 21 has a disk diameter of 120 mm, a center hole diameter of 15 mm, and a disk thickness of 1.2 mm. The thickness of the disk substrate 22 is 1.1 mm, and the thickness of the light transmission layer 24 is 0.1 mm. The reflective film 23 was formed by adding a silver alloy to the disk substrate 22 with a sputtering apparatus. The light transmission layer 24 was formed by irradiating the applied ultraviolet curable resin with ultraviolet rays after applying the ultraviolet curable resin to the disk substrate 22 with a spin coater.

  The temperature in the optical disk manufacturing apparatus was controlled at about 30 ° C. with an air conditioner. The temperature of the disk substrate 22 after adding the reflective film 23 was about 35 ° C.

  Two tables 2 are arranged in the vicinity of the spin coater between the sputtering device and the spin coater for adding the reflective film 23 to the disk substrate 22, and the disk substrate 22 after the addition of the reflective film 23 is arranged on each table 2. Are configured to be supplied to the spin coater via a serial connection. Moreover, the water of the same temperature was poured into the refrigerant flow path 8 of each table 2. The temperature of water flowing through the refrigerant flow path 8 of each table 2 (the temperature set by the temperature controller) is changed in increments of 2 ° C. from 26 ° C. to 32 ° C., the other conditions are the same, and the light transmission layer 24 is formed. did. At any temperature, the surface temperature of the disk substrate 1 immediately before application of the ultraviolet curable resin by the spin coater was almost the same as the temperature of each table 2.

  The thickness distribution in the radial direction of the light transmission layer 24 at each temperature is shown in FIGS. Here, the film thickness (μm) on the vertical axis is an average value of film thickness measurement values at 120 points in the circumference on the same radius, and every 2 mm from the radial positions R22 mm to R56 mm of the disk substrate 22 shown on the horizontal axis. It is the result of measurement.

  5, FIG. 6, FIG. 7, and FIG. 8 are film thickness distributions when the set temperatures of the temperature controller are set to 26 ° C., 28 ° C., 30 ° C., and 32 ° C., respectively. The results are summarized in Tables 1 and 2. Table 1 shows the variation of the film thickness in the radial direction at each temperature, and Table 2 shows the average value of the film thickness at each temperature.

  From these results, it was found that when the temperature of the disk substrate 22 is changed, not only the average value of the film thickness is changed, but also the film thickness distribution in the radial direction is changed. That is, it was found that when the temperature of the disk substrate 22 fluctuates every time the ultraviolet curable resin is applied, the film thickness also fluctuates, which causes a deterioration in yield during manufacturing of the optical disk 21.

  Also, from Table 1, the temperature of the disk substrate 22 with the best film thickness accuracy was 28 ° C., which was different from the device internal temperature of 30 ° C. That is, it has been found that there is a temperature of the disk substrate 22 at which good film thickness accuracy different from the temperature in the apparatus can be obtained. Therefore, it has been found that there is an optimum value for the temperature of the disk substrate 22 immediately before the application of the ultraviolet curable resin, and that the accurate film thickness can always be maintained by always keeping the temperature of the disk substrate 22 at the optimum value.

  In addition, since the viscosity of the ultraviolet curable resin on the disk substrate 22 changes due to a change in the temperature of the disk substrate 22 and the speed at which the resin spreads changes, the average value of the film thickness changes. Can be set to a desired thickness, in this case, 0.1 mm, for example, by adjusting the number of rotations during spin coating.

  From the above, in order to maintain the film thickness distribution with high accuracy at all times, it is necessary to maintain the temperature of the disk substrate 22 immediately before the application of the UV curable resin at an optimum temperature. Using the device has proven effective. A thin film with good film thickness accuracy can be formed by keeping the disk substrate 22 at a predetermined temperature with a temperature control table device at a temperature at which good film thickness accuracy can be obtained.

  The present invention is not limited to the above-described embodiment, and various modifications and applications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the read-only optical disk has been described. However, the present invention is not limited to this, and can be applied to a writable optical disk. The thin film formed by spin coating is not limited to a light transmission layer such as a protective film or an intermediate layer, but can be applied to other thin films formed by spin coating such as a coating layer. Further, the present invention can be applied to the formation of a thin film that requires high film thickness accuracy of other optical recording media such as a magneto-optical disk as well as an optical disk.

  Further, when a plurality of tables 2 are provided, it is not necessary to set the temperature of each table 2 to be the same, and each table 2 may be set to a different temperature as appropriate.

  In addition to controlling the temperature of the disk substrate 1 with the temperature control table device, the temperature in the manufacturing apparatus, the temperature of the resin material to be spin-coated, and the like are high in film thickness accuracy by spin coating in optical disk manufacturing. Needless to say, it is preferable to use a well-known method in forming the thin film.

It is a basic diagram which shows an example of a structure of the temperature control table apparatus which the optical disk manufacturing apparatus by one Embodiment of this invention has. It is a figure for demonstrating an example of formation of the thin film by a spin coat method. It is an expanded sectional view which shows an example of a structure of a single layer optical disk. It is an expanded sectional view which shows an example of a structure of the optical disk of a multilayer structure. It is a figure which shows distribution of the film thickness when the preset temperature of a temperature controller is set to 26 degreeC. It is a figure which shows distribution of the film thickness when the preset temperature of a temperature controller is set to 28 degreeC. It is a figure which shows distribution of the film thickness when the preset temperature of a temperature controller is set to 30 degreeC. It is a figure which shows distribution of the film thickness when the preset temperature of a temperature controller is set to 32 degreeC.

Explanation of symbols

1, 22, 32 ... disk substrate 2 ... table 3 ... upper plate 4 ... lower plate 5 ... center pin 6 ... hole 7 ... vacuum channel 8 ... refrigerant Channel 21 ... Optical disc (single layer)
24, 34, 36 ... Light transmission layer 31 ... Optical disc (multilayer)

Claims (6)

In an apparatus for manufacturing an optical recording medium having an information signal layer and a thin film formed by spin coating on a main surface of a substrate,
A table on which the substrate just before the thin film is formed on the main surface by spin coating is placed;
A plurality of suction ports for fixing the substrate to the table by suction, provided so as to open at equal intervals on each concentric circle on the mounting surface of the table ;
A temperature adjusting means for temperature-controlled refrigerant to regulate the temperature of the placed above the substrate to the table by controlling the temperature of the table by flowing through the refrigerant flow path provided in the table,
An apparatus for producing an optical recording medium, comprising: In claim 1,
An apparatus for manufacturing an optical recording medium, comprising a plurality of the tables, wherein the temperature of the substrate is adjusted in series in each table. In claim 1,
The apparatus for manufacturing an optical recording medium, wherein the temperature adjusting means controls the temperature of the table so that the substrate maintains a predetermined temperature by cooling the substrate. In claim 1,
The apparatus for manufacturing an optical recording medium, wherein the table is made of aluminum or copper. In claim 1,
An apparatus for manufacturing an optical recording medium, wherein the thin film is a light transmission layer through which a laser beam for recording or reproduction is transmitted. In a method for manufacturing an optical recording medium having an information signal layer and a thin film formed by spin coating on a main surface of a substrate,
Place the substrate just before the thin film is formed on the main surface by spin coating on the table,
The mounting surface of the table is provided so as to open at equal intervals on each concentric circle, and the substrate is fixed by a plurality of suction ports for fixing the substrate to the table by suction,
Optical recording medium temperature-controlled refrigerant and adjusting the temperature of the substrate placed on the table by controlling the temperature of the table by flowing through the refrigerant flow path provided in the table Manufacturing method.

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