WO2004025630A1 - 光記録媒体とその製造方法 - Google Patents
光記録媒体とその製造方法 Download PDFInfo
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- WO2004025630A1 WO2004025630A1 PCT/JP2003/010243 JP0310243W WO2004025630A1 WO 2004025630 A1 WO2004025630 A1 WO 2004025630A1 JP 0310243 W JP0310243 W JP 0310243W WO 2004025630 A1 WO2004025630 A1 WO 2004025630A1
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- pit
- depth
- substrate
- recording medium
- optical recording
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/007—Arrangement of the information on the record carrier, e.g. form of tracks, actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/2407—Tracks or pits; Shape, structure or physical properties thereof
- G11B7/24085—Pits
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
- G11B7/258—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of reflective layers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
- G11B7/258—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of reflective layers
- G11B7/259—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of reflective layers based on silver
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/26—Apparatus or processes specially adapted for the manufacture of record carriers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/26—Apparatus or processes specially adapted for the manufacture of record carriers
- G11B7/266—Sputtering or spin-coating layers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/2407—Tracks or pits; Shape, structure or physical properties thereof
- G11B7/24073—Tracks
- G11B7/24079—Width or depth
Definitions
- the present invention relates to a disk-shaped optical disk used for reproducing information.
- a conventional optical recording medium for example, a ROM type optical disk
- embossed pits with a track pitch of 0.74 / m and a minimum pit length of 0.40 ⁇ are formed on a transparent substrate made of polycarbonate or the like, and A1 or the like is formed thereon.
- Information is reproduced by irradiating the information recording surface with a condensed beam from the surface opposite to the surface on which the reflective film is formed.
- Optical recording media for recording and reproducing information by irradiating a light beam are widely used, and there is much expectation that the recording density will be improved in the future.
- JP-A-54-136303 or JP-A-6-150392 can be referred to.
- the magnetron sputtering device strikes the surface of the target installed in the vacuum chamber as fine particles with argon ion, and attaches the particles to the substrate to form a thin film. It is a method of forming.
- the particles struck by the argon ions scatter radially, and particles flying from various angles adhere to the substrate.
- FIG. 2 shows a cross-sectional view of the optical disk. As shown in the figure, the bottom of the shortest pit 204 having the metal reflective film 202 formed on the substrate 201 has a considerably smaller thickness than the bottom of the longest pit 205. Become thin.
- a transparent resin layer 203 is adhered from above the metal reflection film 202 to produce an optical disk.
- the pit depth varies depending on the size of the pit, and the optimum pit depth is maximized so that the reproduced signal is maximized.
- the deviation from the pit depth causes deterioration of the reproduced signal.
- the present invention has been made in view of the above points, and the present invention uses a shorter-wavelength reproducing light beam and an optical system with a higher numerical aperture, compared with the conventional DVD. It is an object of the present invention to provide a next-generation optical disk capable of recording data at high density.
- At least a first metal reflection layer and a transparent resin layer formed on the first metal reflection layer are provided on a substrate on which information is formed as a pit row composed of irregularities at a predetermined track pitch.
- At least a first metal reflection layer and a transparent resin layer formed on the first metal reflection layer are formed on a substrate where the depth of the shortest pit on the substrate is equal to the depth of the longest pit.
- the depth of the shortest pit formed on the signal surface formed on the resin layer side of the first metal reflection film is D (S)
- the depth of the longest pit formed on the signal surface is D
- (L) is set, it satisfies the relationship of 1.0 and D (S) / D (L) ⁇ 1.3.
- At least a first metal reflection layer and a transparent resin layer formed on the first metal reflection layer are formed on a substrate on which information is formed as a pit row composed of irregularities at a predetermined track pitch.
- the depth of the shortest pit formed on the signal surface formed on the resin layer side of the first metal reflective film on a substrate having a depth of greater than the depth of the longest pit is D (S)
- D (L) When the depth of the longest pit formed on the surface is defined as D (L), it satisfies the relational expression of 1Z1. 3 ⁇ D (S) ZD (L) ⁇ 1.3.
- At least a first metal reflection layer and a transparent resin layer formed on the first metal reflection layer are provided on a substrate on which information is formed as a pit row composed of irregularities at a predetermined track pitch.
- the depth d (S) of the shortest pit length of the substrate is smaller than D (S) such that the depth D (S) of the shortest pit formed on the signal surface has a desired value.
- the feature is.
- the first metal reflection layer is an alloy containing Ag as a main component, and the weight ratio of Ag is 97% or more.
- the first metal reflective layer is an alloy represented by a composition formula A gxM, wherein M is at least one selected from Pd, Cu, Pt, Rh, Nd, and Ni; x is characterized by being a value of 97% or more by weight.
- the first metal reflection is made of an alloy material containing Ag or Ag as a main component, and has a film thickness of 10 nm or more and 75 nm or less.
- the first metal reflection film is made of A 1 or a metal material containing A 1 as a main component, and has a thickness of 7 nm or more and 50 nm or less.
- the track pitch is 0.24 111 or more and 0.36 ⁇ m or less, and the shortest pit length is 0.14 111 or more and 0.21 ⁇ or less.
- a metal reflective film is formed so that (S) has a desired value.
- a method for manufacturing an optical recording medium in which information is reproduced by irradiating a light beam to the signal surface is a method for manufacturing an optical recording medium in which information is reproduced by irradiating a light beam to the signal surface.
- the metal reflection film is formed by deposition by ion beam sputtering, and the Ar pressure during film formation is 0.2 Pa or more and 0.7 Pa or less, and the film formation time is 1 s or less.
- the metal reflection film is formed by magnetron sputtering. Specifically, the Ar pressure at the time of film formation is 0.2 Pa or more and 0.7 Pa or less and the film formation time is 3 s or less.
- the present invention is not limited to such an optical disk and a shape.
- the present invention can be applied to various optical recording media having fine irregularities such as a changeable disc in the information recording layer.
- the track pitch and to make the shortest mark length small.
- the track pitch is too narrow, the crosstalk of the RF signal characteristics will increase, and a sufficient system margin cannot be secured.
- the shortest pit length is made too small, the resolution of the reproduction signal decreases, and the jitter value of the reproduction signal deteriorates.
- the wavelength of the reproduction light beam was 405 nm and the numerical aperture NA of the objective lens was 0.85.As a result of repeated studies, the track pitch width was such that the crosstalk signal did not pose a practical problem for the main signal. Was found to be 0.24 ⁇ m or more.
- the optical disc of the present invention aims to provide an optical disc having a recording capacity of 23.3 GB or more using the above-mentioned information reproducing apparatus, (shortest pit length) X (track pitch width) ⁇ 0.0512 ⁇ 2 Must be satisfied. Therefore, the upper limit of the track pitch width is 0.36 ⁇ if the recording capacity is 23.3 G ⁇ and the shortest recording 'mark is 0.14 ⁇ . Similarly, the upper limit of the shortest pit length is 0.23 ⁇ when the recording capacity is 23.3 GB and the track pitch width is 0.24 ⁇ . Therefore, a method of manufacturing an optical disk using a substrate having a track pitch width of 0.224 111 or more and 0.36 ⁇ or less and a minimum pit length of 0.14 111 or more and 0.21 m or less will be described.
- n indicates the refractive index of the transparent resin layer bonded on the metal reflection film.
- the longest pit had a depth of 68 nm, while the shortest pit had a depth of 100 nm.
- the depth of the shortest pit becomes the maximum of the RF signal.
- the resolution of the signal of the shortest pit was significantly reduced, and the quality of the reproduced signal was significantly deteriorated.
- control of the ion beam sputtering device or magnetron sputtering device (b) control under extreme conditions (2) control of the material and thickness of the metal reflective film (3) pit length of the substrate
- control of the material and thickness of the metal reflective film (3) pit length of the substrate
- FIG. 3 shows a schematic configuration diagram of ion beam sputtering.
- This ion sputtering apparatus is composed of a plasma generation chamber 301 and a vacuum vessel 302, and the space therebetween is separated by a grid electrode 303.
- a reflective film material target 304 and a substrate 305 having the above-mentioned fine irregularities in the information recording layer are set.
- the reflection film formation on the substrate is performed by the following steps. First, an argon plasma is formed in the plasma generation chamber, and the generated argon ion beam 306 is accelerated. Then, the reflective film material target 304 is irradiated. The ions hit the reflective film metal particles 307 of the target and form a film on the substrate 305. The metal particles deposited on the substrate fly in a direction perpendicular to the substrate, and thus easily adhere to the bottom of minute pits.
- the reflective film material is an alloy containing Ag as a main component, and the weight ratio of Ag is 9
- composition formula A g M is at least one selected from Pd, Cu, Pt, Rh, Nd, and Ni, and X is a value of 97% or more by weight. Alloys can be used preferably. A 1 or a metal material containing A 1 as a main component can also be used.
- the Ar pressure during sputtering was set to 0 using a magnetron sputtering device.
- the reason why the difference in pit depth between the shortest pit and the longest pit is reduced by setting it to 2 Pa or more and 0.7 Pa or less can be explained as follows.
- the metal particles of the reflective film struck out of the target by the argon gas are obliquely incident on the substrate by being scattered by the argon gas in the chamber before reaching the substrate.
- the probability that these particles are scattered by the argon gas depends on the pressure of the argon gas. The higher the argon gas, the more particles that enter the substrate from an oblique direction. Particles obliquely incident on the substrate are blocked by the tapered surface of the pit, and particles reaching the bottom of the pit are reduced.
- the pressure of the argon gas by reducing the pressure of the argon gas to 0.7 Pa or less, particles incident on the substrate from oblique directions are significantly reduced, and the shortest pit and the longest pit are reduced.
- the pit depth ratio can be suppressed to 1.3 times or less.
- the angle of the tapered surface of the shortest pit was made larger than that of the longest pit by reducing the deposition time to 3 s or less. By forming such a pit shape, a better reproduction signal can be obtained, and at the same time, the tact can be reduced.
- the optical disk medium proposed in the present invention has a transparent resin layer having a thickness of about 0.1 mm formed on a reflective film, a light beam is incident through the transparent resin layer, and a recorded signal is reproduced. It is the one that produces it.
- a method of bonding a transparent resin layer will be described.
- FIG. 13 is a diagram illustrating an example of a step of bonding a transparent film to an information recording surface.
- Metal reflective film 1302 formed 1.1 mm thick substrate 1301 and 25 ⁇ m thick pressure-sensitive adhesive sheet 1303, 75 ⁇ thick transparent resin layer made of polycarbonate 13 04 Is inserted into the vacuum bonding apparatus 1305 as shown in FIG. The thinner the material and thickness of the pressure-sensitive adhesive sheet and the transparent resin layer, the more advantageous for high NA.
- the thickness of the pressure-sensitive adhesive sheet may be reduced. Then, until the air pressure in the vacuum bonding apparatus is 10- 2 Pa, performs decompression by the vacuum pump. When the degree of vacuum is stabilized, the pressure-sensitive adhesive sheet 1303 and the transparent resin layer 1304 are stuck on the metal reflective film side. Then, as shown in FIG.
- FIG. 1 is a structural sectional view of the optical disk of the present invention. Irrespective of whether the substrate is transparent or not 1.
- a pit unevenness 102 for data information is formed on one side of a substrate 101 having a thickness of 1 mm, and a metal reflective layer 103 is formed thereon.
- a transparent film as the protective film 104 having a small thickness of 0.1 mm is applied.
- a 12 cm optical disc substrate having a track pitch of 0.32 ⁇ and a minimum pit length of 0.149 ⁇ was manufactured using (1, 7) RLL modulation.
- This optical disc can record 25 GB of information.
- the pit depth 105 on the substrate was made to be 65 nm.
- the substrate was mounted on a substrate holder in a vacuum chamber of a stationary opposing magneto port sputtering apparatus, and the inside of the vacuum chamber was evacuated by a vacuum pump.
- the pressure gauge indicated 2 * 1 CT 6 Pa.
- An Ag 981 P d ⁇ Cu ⁇ (subscript is a percentage by weight) target was attached to the force sword, and argon gas was introduced at 0.3 Pa to start sputtering.
- the film formation time was 2.2 s, and power was applied so that the film thickness of the mirror portion became 60 nm.
- the pit depth 402 (hereinafter referred to as D (S)) of the shortest pit length was 75 nm
- the pit depth 403 (hereinafter referred to as D (L)) of the longest pit length was 65 nm. That is, D (S) / D (L) was 1.15.
- a tangent line 404 is drawn from a point located at a depth of 1/2 XD (S) on the taper surface of the shortest pit, and an angle (hereinafter referred to as “S (S) 405) became 82 degrees.
- a tangent line 406 is drawn from a point located at a depth of 1/2 XD (L) on the tapered surface of the longest pit, and the angle between the tangent line 406 and the mirror surface where no pit is formed (hereinafter referred to as “hi ( L)) 407 became 78 °.
- D (S) ZD (L) varies greatly depending on the argon gas pressure during film formation
- the ratio of D (S) / D (L) is measured by changing the argon gas pressure during film formation.
- the resulting graph is shown in FIG.
- the film formation rate was changed, so that the film thickness of the reflective film formed on the mirror surface was kept constant from 2.1 s to 2.6 s.
- the film formation time was adjusted within the range.
- FIG. 6 shows a graph in which the horizontal axis represents the deposition time and the vertical axis represents a (S) / a (L).
- FIG. 11 shows a schematic cross-sectional view when the deposition time was 3.5 s and ⁇ (S) became larger than Hi (L).
- a transparent resin layer was formed on the metal reflective film using a pressure-sensitive adhesive sheet. At this time, the thickness of the transparent resin layer was adjusted to 100 m.
- laser light is incident on the optical disk from the transparent resin layer side by the objective lens, is focused on the metal reflective film, and changes in the light intensity of the reflected light are detected as pit recording information. I went by.
- the signal was reproduced and evaluated by using an information reproducing apparatus in which the wavelength of the reproducing light beam; I was 405 nm and the numerical aperture NA of the objective lens was 0.85. It is easy to guess that the signal shape of a read-only optical disk is influenced greatly by the shape and depth of the mark with the shortest pit length having the smallest signal amplitude. In the present embodiment, the correlation between the pit shape and the reproduced signal quality was quantitatively investigated. Considering the dispersion of the reflective film when a large number of discs are manufactured and the production variation of the signal reproducing device, the minimum value of the jitter value that indicates the superiority of the reproduced signal must be 6.5% or less.
- each parameter of (1) the thickness of the metal reflection film (2) D (S) / D (L) (3) ⁇ (S) / ⁇ (L) depends on the pit shape and depth.
- Figure 14 shows the film thickness of the metal reflective film when AgPdCu is used for the metal reflective film (the film thickness is the value of the mirror surface where no pits are recorded on the substrate) and the reproduced signal. 2 shows the relationship between the minimum values of the jitter values.
- Figure 15 shows the film thickness of the metal reflective film and the jitter value of the reproduced signal when A 1 (the film thickness value represents the film thickness of the mirror surface portion where no pits are recorded on the substrate) is used for the metal reflective film. Shows the relationship between the minimum values of. Two types of substrates are prepared.
- the solid line indicates the depth; LZ 3n substrate, the dotted line represents the data of the depth / 5n substrate.
- the thickness of the metal reflection film is too small, a sufficient amount of reflected light cannot be obtained, so that the quality of the reproduced signal deteriorates and the jitter value increases. From Figures 14 and 15, it was found that when using AgP dCu as the metal reflective film material, 1 Onm or more was required, and when using A1, 7 nm or more was required. Also, when the thickness of the metal reflection film is increased, the depth of the shortest pit is increased, so that the reproduced signal deteriorates. Playback signal has pit depth; L / 4 When it is near n, the highest signal amplitude is obtained.
- the metal reflection film when a film is formed on an optical disk substrate on which minute pits are formed as proposed in the present invention, the metal reflection film is less likely to be formed at the bottom of the small pits. There is a phenomenon that the size increases. In other words, for an optical disk with a pit depth of L / 5n on the substrate, the depth of the shortest pit length increases as the metal reflection film increases, and the reproduced signal amplitude becomes maximum. Since the value is close to 4 n, the jitter value takes a minimum value at a certain film thickness (about 73 nm for AgPdCu alloy).
- the reproduced signal deteriorates.
- the range of the film thickness of the metal reflective film having the minimum value of the jitter value of 6.5% or less is narrower than that of the optical disk formed on the substrate having the pit depth of n. . Therefore, the upper limit of the metal reflection film is a film thickness at which a good signal can be obtained when the film is formed on the substrate having the deepest pit depth.
- the preferred film thickness when the AgPdCu alloy is used for the metal reflection film is 10 nm or more and 75 nm or less.
- the preferable thickness of S is 7 nm or more and 50 nm or less.
- Figure 7 shows a graph with the ratio of D (S) / D (L) on the horizontal axis and the jitter value of the reproduced signal on the vertical axis.
- the ratio of D (S) / D (L) exceeds 1.30, the reproduced signal deteriorates. This is presumably because the pit depth of the shortest mark has become deeper and the amplitude of the reproduced signal has become smaller. Therefore, in order to obtain a good reproduced signal, the ratio of D (S) ZD (L) is preferably larger than 1.0 and 1.3 or less. Also, from Fig.
- the argon pressure during film formation that satisfies 1.0 and D (S) / D (L) ⁇ 1.3 is 0.2 Pa or more and 0.7 Pa or less. . Therefore, when a reflective film is formed using a magnetron sputtering apparatus, it is preferable that the argon pressure at the time of film formation be 0.2 Pa or more and 0.7 Pa or less.
- the optical disk used in this study always satisfied the relationship of Hi (S)> a (L).
- the film is formed by the stationary facing DC magnetron sputtering apparatus.
- D (S) / D (L) ⁇ 1.3, ⁇ (S)> a
- the means is not limited as long as the film forming apparatus and the film forming conditions satisfy (L).
- the Ag PdCu alloy is used.
- An Ag alloy containing at least one metal selected from the group consisting of Ni and Ni can also be used as the metal material.
- a 12 cm optical disk substrate having a track pitch of 0.26 ⁇ m, a minimum pit length of 0.149 ⁇ , and recording 30 GB of information was manufactured.
- the method for manufacturing the substrate is the same as that in Embodiment 1.
- a substrate with a pit depth of 65 nm was used.
- A1 was formed on the optical disk substrate so that the reflection film thickness at the mirror surface became 40 nm.
- Metal reflection SMo used pure A1 in this example, but added a small amount of material such as Ti, Cr, and Co to the target material. However, it is also possible to use a reflective film having excellent corrosion resistance.
- the pit depth D (S) of the shortest pit length after A1 film formation was 72 nm, and ⁇ (S) was 85 °.
- the pit depth D (L) of the longest pit length was 69 nm, and the pit depth (L) was 83 °.
- an optical disk having a ratio of D (S) / L (L) of 1.04 was obtained by the ion beam sputtering apparatus.
- a transparent resin layer was bonded on the metal reflection film.
- the signal was reproduced and evaluated using an information reproducing apparatus with a wavelength of the reproducing light beam; L of 405 nm and a numerical aperture of the objective lens of 0.85.
- the jitter value of the shortest pit length with the smallest signal amplitude has a great effect on the quality of the reproduced signal of a read-only optical disk. Therefore, in the present embodiment, the magnitude of D (S) and the quality of the reproduced signal were examined. Seven types of substrates with different pit depths (30 ⁇ ! To 90 nm) were prepared, and film formation was performed using an ion beam sputtering apparatus so that A1 of 40 nm was deposited on the mirror surface.
- the Ar pressure during film formation was set to 0.3 Pa, and the film formation time was set to 0.8 s.
- the film formation time tends to be longer than that in a magneto-sputtering apparatus.
- the reflective film was formed by setting the pressure to 0.2 Pa or more and 0.7 Pa or less, and setting the film forming time to 1 s or less.
- Table 1 shows the pit depth on the substrate, the D (S) and D (L) values and the signal jitter after the mirror surface portion of A1 was formed to a thickness of 40 nm by an ion beam sputtering system. Data values.
- the pit depth is 1 / (4Xn)
- the reproduced signal amplitude is maximized.However, the pit depth is determined from the maximum depth of the reproduced signal. Even if they are misaligned, the pit width and the optimal pit shape can be optimized to increase the pit depth margin.
- D (S) was not less than about 50 nm and not more than about 80 nm in order to obtain a sufficient reproduction margin, and this was; L (5 Xn) or more; lZ (3 Xn ) It corresponds to the following range.
- the ratio D (S) / ⁇ (L) of the shortest pit depth to the longest pit depth after the formation of the metal reflective film is preferably 1.0 or more and 1.3 or less. Therefore, the optimum range of the shortest pit depth (hereinafter referred to as d (S)) on the substrate before forming the reflective film is: (5 Xn) /1.3 or more / (3 Xn) /1.00, that is, 1 / (6.5 Xn) or more; 1 / (3Xn).
- a 12 cm optical disc substrate having a track pitch of 0.26 m and a minimum pit length of 0.149 / zm and recording 30 GB of information was manufactured.
- Ma By using reactive ion etching (RIE) in the stirling process, a substrate with the shortest mark length and reduced pit depth was used.
- RIE reactive ion etching
- an electron beam resist 902 is applied to a master 901 made of Si 02 (FIG. 9A).
- a master 901 made of Si 02 FIG. 9A.
- minute pits are formed in a spiral (FIG. 9 (b)).
- development was performed to remove the electron-beam exposed portion 903, exposing the surface of the master (Fig. 9 (c)).
- the pits were formed on the surface of the master by reactive ion etching (RIE) using the non-developed surface as a mask (Fig. 9 (d)).
- RIE reactive ion etching
- a metal stamper 904 was formed by attaching a metal on the conductive film, and was peeled off from the master (FIG. 9 (f)).
- a metal stamper was installed on an injection molding machine, and a substrate made of polycarbonate resin or the like was manufactured.
- etching is performed by introducing CHF 3 gas into the chamber of the ion etching apparatus.
- the pressure of CHF 3 gas was set to 0.4 Pa
- the RF power was set to 300 W
- the etching time was set to 6 minutes.
- the optical disk substrate injection-molded from the metal stamper subjected to such an etching process has a shortest pit length depth d (S) force of S52 nm and a longest pit length depth d (L) of 60 nm, that is, d (L / ⁇ (S) became 1.15.
- CHF 3 gas is used.
- the same etching effect can be obtained by mixing CF 4 gas, a mixed gas of CHF 3 and CF 4 , or a non-volatile gas such as Ar into these gases. can get.
- a reflection film was formed on this optical disk substrate by a magneto-sputtering apparatus.
- a 1 Ti is used for the reflective film material, and the thickness of the mirror surface is adjusted to 50 nm.
- Sputtering was performed. Note that the argon pressure during film formation was 0.4 Pa, and the film formation time was 1 s.
- the optical disk after film formation was analyzed by AFM. As described in Embodiment 1, in magnetron sputtering, since the reflective film tends to hardly reach the bottom of a pit having a small pit shape, the pit depth of the shortest pit length becomes larger after film formation, and (S) was 62 nm, and D (L) was 60 nm.
- FIG. 10 shows a schematic cross-sectional view after A 1 Ti film formation.
- the difference in pit depth after film formation can be reduced.
- the pit depth is changed according to the pit size using RIE.
- many such mastering processes have been proposed (for example, see Patent Documents 1 and 2).
- the same effect can be expected by using a substrate in which the pit depth on the substrate is within the range of l ⁇ d (L) / ⁇ (S) ⁇ 1.3.
- the mastering step is not limited to the one shown in the present embodiment.
- the present invention can be applied to a multilayer optical recording medium configured by stacking a plurality of information recording layers in order to achieve a large information recording capacity.
- An example of a method for manufacturing the multilayer optical recording medium will be described with reference to FIG.
- a 45 nm-thick first metal reflective film 1202 of, for example, an A1 film is formed on the main surface of the magnetron sputtering apparatus described above.
- a stamper substrate 1205 made of polycarbonate having a pit thickness of 1.1 mm is cured with a photo-curable resin (2) 1204 having excellent releasability at about 10 ⁇ m.
- the substrate 1201 and the stamper substrate 1205 are bonded together via a photo-curing resin having strong adhesiveness (1) 1203 (FIG. 12 (a)).
- the bonding method is as follows.
- the substrate 1201 is set on a spin coater such that the first metal reflection film surface faces upward, and the photocurable resin (1) 1203 is dropped. After that, rotate the disk
- the reading of information from the two-layer optical recording medium is performed by irradiating optical laser light from the transparent resin layer 1207 side.
- the two-layer optical recording medium Although the method of forming the body was shown, it is also possible to manufacture a multilayer optical recording medium with two or more layers by laminating a substrate solidified with a light-hardening resin after the process in Fig. 12 (d).
- an olefin resin having a strong releasability from the photocurable resin can be used for the stamper substrate.
- This bonding method will be described with reference to FIG.
- a stamper substrate 1604 made of a 1.1-mm thick olefin having fine pits is prepared. These substrates 1601 and stamper substrate 1604 are bonded together via photocurable resin 1603 (Fig. 16
- the substrate 1601 is set on a spin coater so that the first metal reflection film surface 1602 faces upward, and the photocurable resin 1603 is dropped. Then, the disk is rotated so that the thickness of the photo-curable resin 1603 becomes uniform within the disk. On top of that, a stamper substrate 1604 can be overlaid.
- a transparent resin layer 1606 having a thickness of 7 ⁇ is bonded using, for example, a pressure-sensitive adhesive sheet. Multilayering is also possible by applying a curable resin layer and transferring the stamper substrate before bonding the transparent resin layer 1606.
- the pressure-sensitive adhesive sheet is used for bonding the transparent resin layer.
- a light-curable resin instead of the pressure-sensitive adhesive sheet, a light-curable resin, a dry photopolymer, or the like, which has an adhesive property and is transparent. Certain media may be used. Also, it is possible to form a transparent resin layer only with a pressure-sensitive adhesive sheet or only with a photocurable resin without bonding a transparent resin layer. (The invention's effect)
- the pit depth of the shortest pit length and the pit depth of the longest pit length are reduced by limiting the film forming conditions when forming the reflective film. And the angle between the tapered surface of the shortest pit and the mirror surface can be increased. Also, by providing a reflective film using a substrate having different pit depths, the pit depth after forming the reflective film is made uniform, and a jitter value is reduced, and an optical disk capable of reproducing a waveform is provided. Can be. Thus, the present invention greatly contributes to increasing the density of an optical disk.
- FIG. 1 is a structural sectional view of the optical disk of the present invention.
- Figure 2 Cross section of an optical disc.
- Figure 3 Schematic diagram of ion beam sputtering.
- Figure 4 Schematic diagram of the optical disc section.
- Figure 5 Graph measuring the ratio of D (S) / D (L).
- Figure 6 Graph showing the deposition time on the horizontal axis and ⁇ (S) / a (L) on the vertical axis.
- Figure 7 Graph with the ratio of D (S) / D (L) on the horizontal axis and the jitter value of the reproduced signal on the vertical axis.
- Figure 8 Graph with a (S) / a (L) plotted on the horizontal axis and the jitter value of the reproduced signal on the vertical axis c
- Figure 9 Mastering process for manufacturing substrates with different pit depths depending on the pit size
- FIG. 10 Schematic cross section after A 1 Ti film formation.
- Fig. 11 Schematic cross-section when the deposition time is 3.5 s and a (S) is larger than hi (L).
- FIG. 12 is a diagram illustrating an example of a method for manufacturing a multilayer optical recording medium.
- FIG. 13 is a diagram showing an example of a process of bonding a transparent film to an information recording surface.
- Fig. 14 Thickness of metal reflection film when Ag PdCu is adopted for metal reflection film (thickness value indicates the thickness of mirror surface where pits are not recorded on the substrate) and reproduction signal The figure which shows the relationship of the minimum value of a jitter value.
- FIG. 4 is a diagram showing the relationship between the thickness of the metal reflection film and the minimum value of the jitter value of the reproduction signal when (representing the value of the film thickness of a portion) is adopted.
- FIG. 16 A diagram showing a method of bonding an olefin resin having a strong releasability from a photohardening resin to a stamper substrate.
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Optical Record Carriers And Manufacture Thereof (AREA)
- Manufacturing Optical Record Carriers (AREA)
- Optical Recording Or Reproduction (AREA)
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2003255002A AU2003255002A1 (en) | 2002-09-13 | 2003-08-12 | Optical recording medium and method for producing the same |
EP03795219A EP1544851A1 (en) | 2002-09-13 | 2003-08-12 | Optical recording medium and method for producing the same |
JP2004535870A JPWO2004025630A1 (ja) | 2002-09-13 | 2003-08-12 | 光記録媒体とその製造方法 |
US10/527,190 US20060044996A1 (en) | 2002-09-13 | 2003-08-12 | Optical recording medium and method for producing the same |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2002268535 | 2002-09-13 | ||
JP2002/268535 | 2002-09-13 |
Publications (1)
Publication Number | Publication Date |
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WO2004025630A1 true WO2004025630A1 (ja) | 2004-03-25 |
Family
ID=31986770
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2003/010243 WO2004025630A1 (ja) | 2002-09-13 | 2003-08-12 | 光記録媒体とその製造方法 |
Country Status (7)
Country | Link |
---|---|
US (1) | US20060044996A1 (ja) |
EP (1) | EP1544851A1 (ja) |
JP (1) | JPWO2004025630A1 (ja) |
KR (1) | KR20050042804A (ja) |
CN (1) | CN1692412A (ja) |
AU (1) | AU2003255002A1 (ja) |
WO (1) | WO2004025630A1 (ja) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009259368A (ja) * | 2008-04-21 | 2009-11-05 | Sony Corp | 光ディスク製造方法、ディスク原盤製造方法、光ディスク |
US7619962B2 (en) | 2005-12-15 | 2009-11-17 | Victor Company Of Japan, Ltd. | Optical disc and method of producing the same |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008165860A (ja) * | 2006-12-27 | 2008-07-17 | Toshiba Corp | 光ディスク、光ディスク再生装置および光ディスク再生方法 |
FR2944132A1 (fr) * | 2009-04-01 | 2010-10-08 | Commissariat Energie Atomique | Structure de stockage optique d'informations et procede d'optimisation de realisation de cette structure. |
Citations (4)
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JPH0512671A (ja) * | 1991-07-05 | 1993-01-22 | Fuji Photo Film Co Ltd | 光情報記録方法 |
JPH0554393A (ja) * | 1991-08-27 | 1993-03-05 | Hitachi Maxell Ltd | 情報記録媒体およびその駆動装置 |
JPH11250506A (ja) * | 1998-03-03 | 1999-09-17 | Yamaha Corp | 光ディスクおよび光ディスク原盤の露光方法 |
JP2002008269A (ja) * | 2000-06-22 | 2002-01-11 | Sony Corp | 光学記録媒体およびその製造方法 |
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JP3268126B2 (ja) * | 1994-07-06 | 2002-03-25 | シャープ株式会社 | 光記録媒体 |
US5602824A (en) * | 1994-08-12 | 1997-02-11 | Nikon Corporation | Optical disk capable of recording information on both land and groove tracks |
JPH09320117A (ja) * | 1996-05-28 | 1997-12-12 | Pioneer Electron Corp | 光ディスク |
JPH10106040A (ja) * | 1996-09-26 | 1998-04-24 | Canon Inc | 光学的情報記録媒体および光学的情報記録再生装置 |
JP2001266413A (ja) * | 2000-03-17 | 2001-09-28 | Toshiba Corp | 光ディスク、光ディスク再生装置、及び光ディスク再生方法 |
US7016295B2 (en) * | 2000-04-26 | 2006-03-21 | Optical Disc Corporation | Hybrid discs displaying certain dimensional values |
JP2004127468A (ja) * | 2002-10-07 | 2004-04-22 | Toshiba Corp | 光ディスクおよび光ディスク装置 |
US20040081069A1 (en) * | 2002-10-17 | 2004-04-29 | Hitachi Maxell, Ltd. | Optical information-recording medium and method for producing the same |
TWI251233B (en) * | 2002-11-19 | 2006-03-11 | Hitachi Maxell | Optical information recording medium and method of manufacturing the same |
JP4170132B2 (ja) * | 2003-04-14 | 2008-10-22 | 松下電器産業株式会社 | 光記録媒体 |
-
2003
- 2003-08-12 WO PCT/JP2003/010243 patent/WO2004025630A1/ja not_active Application Discontinuation
- 2003-08-12 CN CNA038215918A patent/CN1692412A/zh active Pending
- 2003-08-12 AU AU2003255002A patent/AU2003255002A1/en not_active Abandoned
- 2003-08-12 KR KR1020057004104A patent/KR20050042804A/ko not_active Application Discontinuation
- 2003-08-12 JP JP2004535870A patent/JPWO2004025630A1/ja not_active Withdrawn
- 2003-08-12 US US10/527,190 patent/US20060044996A1/en not_active Abandoned
- 2003-08-12 EP EP03795219A patent/EP1544851A1/en not_active Withdrawn
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH0512671A (ja) * | 1991-07-05 | 1993-01-22 | Fuji Photo Film Co Ltd | 光情報記録方法 |
JPH0554393A (ja) * | 1991-08-27 | 1993-03-05 | Hitachi Maxell Ltd | 情報記録媒体およびその駆動装置 |
JPH11250506A (ja) * | 1998-03-03 | 1999-09-17 | Yamaha Corp | 光ディスクおよび光ディスク原盤の露光方法 |
JP2002008269A (ja) * | 2000-06-22 | 2002-01-11 | Sony Corp | 光学記録媒体およびその製造方法 |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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US7619962B2 (en) | 2005-12-15 | 2009-11-17 | Victor Company Of Japan, Ltd. | Optical disc and method of producing the same |
JP2009259368A (ja) * | 2008-04-21 | 2009-11-05 | Sony Corp | 光ディスク製造方法、ディスク原盤製造方法、光ディスク |
Also Published As
Publication number | Publication date |
---|---|
KR20050042804A (ko) | 2005-05-10 |
CN1692412A (zh) | 2005-11-02 |
US20060044996A1 (en) | 2006-03-02 |
EP1544851A1 (en) | 2005-06-22 |
JPWO2004025630A1 (ja) | 2006-01-12 |
AU2003255002A1 (en) | 2004-04-30 |
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