WO2002005275A1 - Support d'enregistrement d'information - Google Patents

Support d'enregistrement d'information Download PDF

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Publication number
WO2002005275A1
WO2002005275A1 PCT/JP2000/004524 JP0004524W WO0205275A1 WO 2002005275 A1 WO2002005275 A1 WO 2002005275A1 JP 0004524 W JP0004524 W JP 0004524W WO 0205275 A1 WO0205275 A1 WO 0205275A1
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WO
WIPO (PCT)
Prior art keywords
film
layer
protective layer
thickness
substrate
Prior art date
Application number
PCT/JP2000/004524
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English (en)
Japanese (ja)
Inventor
Akemi Hirotsune
Toshimichi Shintani
Motoyasu Terao
Keikichi Ando
Yumiko Anzai
Original Assignee
Hitachi, Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi, Ltd. filed Critical Hitachi, Ltd.
Priority to PCT/JP2000/004524 priority Critical patent/WO2002005275A1/fr
Priority to TW090108017A priority patent/TW556170B/zh
Publication of WO2002005275A1 publication Critical patent/WO2002005275A1/fr

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Classifications

    • 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
    • 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
    • G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
    • G11B7/0045—Recording
    • G11B7/00454—Recording involving phase-change effects
    • 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
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/0938—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following servo format, e.g. guide tracks, pilot signals

Definitions

  • the present invention relates to an optical information recording medium, and
  • phase change of the film material also called a phase transition field
  • photowriting book There are various known principles for recording information on a thin film (recording film) by irradiating a laser beam. Among them, the phase change of the film material (also called a phase transition field) and the photowriting book are known.
  • a light source with a wavelength of around 660 nm which is generally called a red laser
  • a red laser which is generally called a red laser
  • These information recording medium lower protective layer on a substrate, Ge SBT e system such as a recording film of, Zn S- S i 0 2 based upper protective layer has a reflective layer were sequentially stacked, the wavelengths around 660 nm
  • the refractive index of the recording film is larger in the crystalline state than in the amorphous state.
  • the refractive index of the recording film in the crystalline state is smaller than that in the amorphous state at wavelengths around 400 nm, and the refractive index of the recording film is less than that at the wavelength of 660 nm.
  • the difference between the optical constants of the crystallinity is small, and the contrast is small.
  • the spot diameter is smaller than that at 660 nm, so that the recording film heated by laser light irradiation during recording and erasing is quickly cooled, and the recording film reaches the crystallization temperature required for erasing. Since it is difficult to hold for a sufficient time, the erasing characteristics deteriorate.
  • OD SZI SOM '97 Preliminary Proceedings, p. 46 shows an information recording medium for a wavelength of about 400 nm. In this medium, only the upper protective layer exists between the recording film and the reflective layer. However, it does not show that the contrast is low or the erasing characteristics are improved. Further, a similar information recording medium for a wavelength of about 400 nm is disclosed in Japanese Patent Application Laid-Open No. 11-39716 (Reference 2), but the thickness of the upper protective layer is very thin, 25 nm or less. material consists of a mixture of Z n S and S i O 2.
  • a short-wavelength laser near the wavelength of 400 nm is generally called a blue, blue-green, blue-violet, or green laser in comparison with a long-wavelength red laser, but in this specification, Collectively referred to as blue lasers.
  • phase change and “phase change” include not only the phase change between a crystal and an amorphous phase, but also melting (change to a liquid phase) and recrystallization, and a phase change between crystalline states.
  • atomic sequence change is used.
  • Mark edge recording refers to a recording method in which an edge portion of a recording mark is made to correspond to a signal "1", and between and within marks are made to correspond to a signal "0".
  • an optical disk refers to a method for reproducing information by light irradiation and an information recording medium for reproducing information by light irradiation. Disclosure of the invention
  • an object of the present invention is to provide an information recording medium having good recording, erasing, and reproducing characteristics by improving erasing characteristics and contrast when performing recording, erasing, and reproducing with a blue laser. .
  • An information recording medium comprises: a substrate; a recording film on which information is recorded by an atomic arrangement change caused by light irradiation; a lower protective layer provided between the recording film and the substrate;
  • the recording film has a higher refractive index in an amorphous state at a reproduction wavelength than a refractive index in a crystalline state at a reproduction wavelength. It is characterized in that a cooling control layer is provided between the reflective layer and the reflective layer.
  • the upper protective layer and the lower protective layer provided above and below the recording film have a function of protecting the recording film.
  • the cooling control layer provided between the upper protective layer and the reflective layer controls the recording film to gradually cool by gradually flowing heat compared to when the upper protective layer and the reflective layer are in contact. And has the function of improving the erasing characteristics.
  • the thermal conductivity of the cooling control layer is too small, the recording characteristics will deteriorate.
  • the erasure characteristics and the recording characteristics are maintained favorably by controlling the temperature within a proper range.
  • the thermal conductivity of the cooling control layer is higher than the thermal conductivity of the upper protective layer.
  • It preferably has a thickness of 10 to 230 nm, and the total thickness of the upper protective layer and the cooling control layer is preferably 60 nm or more and 240 nm or less.
  • the cooling control layer and the upper protective layer preferably have a refractive index difference of 0.1 or more at the reproduction wavelength. Further, it is preferable that a contrast enhancement layer having a refractive index difference of 0.1 or more between the substrate and the lower protective layer is provided.
  • the substrate has a concavo-convex structure formed of a continuous or partially continuous groove on the contact surface with the film.
  • the concavities and convexities the closer the distance to the light incident side substrate surface is, the longer the distance is, and the farther is the land.
  • the signal level ratio of the signal obtained from the recording mark recorded in the groove and the signal obtained from the recording mark recorded in the land can be close to one.
  • the substrate has irregularities formed of continuous or partially continuous grooves on the contact surface with the film, and the irregularities having a shorter distance from the substrate surface on the light incident side are grouped, and the more distant are lands and groove widths.
  • W sg to land width W s 1 W sg / W s 1 W s
  • d 2 (nm) the total thickness of the lower protective layer and the contrast enhancement layer
  • the signal obtained from the recording mark recorded in the group and the recording mark recorded in the land can be close to 1.
  • it has a structure in which a reflective layer, a cooling control layer, an upper protective layer, a recording film, and a lower protective layer are laminated in this order on a second substrate on which light does not enter, and the second substrate has a contact surface with the film.
  • the land has a concavity and convexity consisting of continuous or partially continuous grooves, of which the distance from the substrate surface on the light incident side is closer to the land, the farther one is the group, and the group width at the contact surface with the film of the second substrate
  • W sg is the ratio of W sg to land width W s 1
  • W sg ZW s 1 is W s
  • the total thickness of the reflective layer, cooling control layer, and upper protective layer is e (nm)
  • the signal obtained from the recording mark recorded in the group and the signal recorded on the land were recorded.
  • the signal level ratio of the signal obtained from the recording mark can be made close to 1.
  • FIG. 1 is a schematic sectional view of an example of the information recording medium according to the present invention.
  • FIG. 2 is a schematic cross-sectional view of an information recording medium having a conventional structure.
  • FIG. 3 is a diagram showing a recording waveform used for evaluating the recording / reproducing characteristics of the information recording medium of the present invention.
  • FIG. 4 is a schematic sectional view showing another example of the information recording medium according to the present invention.
  • FIG. 5 is a schematic cross-sectional view of a substrate portion of an example of an information recording medium according to the present invention.
  • FIG. 6 is a schematic sectional view of a substrate portion of another example of the information recording medium according to the present invention.
  • FIG. 7 is a schematic sectional view of a substrate portion of another example of the information recording medium according to the present invention.
  • FIG. 8 is a schematic sectional view of another example of the information recording medium according to the present invention.
  • FIG. 9 is a diagram showing the relationship between the total thickness of the upper protective layer and the cooling control layer and the erasing ratio.
  • FIG. 1 is a schematic diagram showing a cross-sectional structure of a disc-shaped information recording medium according to a first embodiment of the present invention.
  • FIG. This medium was manufactured as follows. First, (ZnS) 8 having a film thickness of about 80 nm was formed on a polycarbonate substrate 1 having a diameter of 12 cm, a thickness of 0.6 mm, and a tracking groove on the surface.
  • (ZnS) 8 having a film thickness of about 80 nm was formed on a polycarbonate substrate 1 having a diameter of 12 cm, a thickness of 0.6 mm, and a tracking groove on the surface.
  • the second disk member is made of (ZnS) 8 with a film thickness of about 80 nm on the polycarbonate substrate 1 '.
  • first disk member and the second disk member are bonded together with their respective reflective layers 6 and 6 'through an adhesive layer 7, and the disk-shaped information recording medium shown in FIG.
  • FIG. 2 is a schematic diagram showing a cross-sectional structure of the medium.
  • This medium was manufactured as follows. First, a (ZnS) 8 film having a thickness of about 80 nm was formed on a polycarbonate substrate 1 having a diameter of 12 cm and a thickness of 0.6 mm and having tracking grooves on its surface. (S i 0 2) 20 layer and the thickness of about 5 nm of C r 2 O 3 lower protective layer 2 which film is laminated comprising a thickness of about 1 811 111 06 5 813 2 chome 6 8 recording film 3, the film thickness Upper protective layer 4 consisting of a Cr 2 O 3 film of about 5 nm and a (Zn S) 80 (S i 0 2 ) 20 film of about 1 O nm thick, AggsP d Ci of about 80 nm thick ⁇ The reflective layer 6 consisting of a film is formed Was. The formation of the laminated film was performed by a magnetron 'sputtering apparatus. Thus, a first disk member was obtained.
  • the second disk member is made of (ZnS) 8 with a film thickness of about 80 nm on the polycarbonate substrate 1 '.
  • (S i 0 2) 20 lower protective layer 2 of film and thickness C r 2 ⁇ 3 film of about 5 nm is formed by a product layer ', thickness of about 1 811 111 0 6 5 813 2 chome 6 8 recording film 3 '
  • the film thickness of the Cr 2 O 3 film is about 5 nm and the film thickness of about 10 11111 (211 3) 8 .
  • a reflective layer 6 'made of a film was formed sequentially.
  • first disk member and the second disk member are bonded together with the respective reflective layers 6 and 6 'interposed therebetween via an adhesive layer 7, and the disk-shaped information recording medium shown in FIG.
  • the medium (disk A, disk B) is rotated so that the linear velocity at a point on the recording track is 6 m_ / s, the laser light power of a semiconductor laser with a wavelength of about 810 nm is set to ⁇ 0 OmW, and the substrate 1
  • the recording film 4 was irradiated with the light in the form of an oblong spot elongated in the radial direction of the medium.
  • the movement of the spot was shifted by a spot length of 124 in the radial direction of the medium per rotation of the medium.
  • initial crystallization was performed. This initial crystallization may be performed once, but when it is repeated three times, the rise in noise due to the initial crystallization has been slightly reduced.
  • This initial crystallization has the advantage that it can be performed at high speed.
  • the power of the recording laser beam is changed between the intermediate power level Pe (3 mW) and the high power level Ph (7 mW) while performing tracking and automatic focusing on the recording area of the recording film 4 where the initial crystallization is completed. Then, information was recorded.
  • the linear velocity of the recording track is 8 mZs
  • the wavelength of the semiconductor laser is 410 nm
  • the numerical aperture (NA) of the lens is 0.65.
  • Amorphous or amorphous formed in the recording area by the recording laser beam The portion near this is the recording point.
  • the reflectivity of this medium is higher in the crystalline state, and the reflectivity of the recorded and amorphous region is lower.
  • the power ratio between the high level and the intermediate level of the recording laser beam is preferably in the range of 1: 0.3 to 1: 0.7.
  • another power level may be set for each short time. As shown in FIG. 3, during formation of one recording mark, the power is repeatedly lowered by half the window width (TwZ 2) to the bottom power level Pb lower than the intermediate power level Pe and the cooling power.
  • TwZ 2 half the window width
  • the cooling power level Pc is lower than the intermediate power level Pe and higher than or equal to the bottom power level Pb.
  • This waveform has the characteristic that the first pulse width Tp changes according to the combination of the recording mark and the length of the space provided immediately before the mark, and the cooling pulse width Tc (lower to the Pc level at the end of the recording pulse).
  • Time width is determined by the combination of the recording mark and the subsequent space length of the mark. The shorter the space length just before the mark, the longer the mark, the shorter the Tp. The longer the space length immediately before the mark, the shorter the mark, the longer the Tp.
  • the jitter reduction effect was significant when the Tp of the recording waveform for recording the 6 Tw mark was particularly long. Also, as the subsequent space length is longer and the mark is longer, Tc is shorter, and as the subsequent space length is shorter and the mark is shorter, Tc is longer.
  • FIG. 3 shows only the recording waveforms of 3 Tw, 4 Tw, 6 Tw, and 11 Tw
  • 5 Tw is a high-power pulse of TwZ 2 in a series of high-level pulse trains of the recording waveform of 6 Tw.
  • the bottom power level Pb of TwZ2 immediately after the level Ph and the immediately following level Pb are respectively reduced one by one.
  • the recording waveform for 7 Tw to 10 Tw has a high power level Ph of Tw / 2 and a bottom power level Pb of Tw / 2 immediately before the pulse of the high power level at the end of the recording waveform for 6 Tw. Each one is added. Therefore, 11 Tw is obtained by adding 5 sets.
  • the shortest recording mark length corresponding to 3 Tw was 0.26 m.
  • the laser light power was reduced to the low power level P r (0.5 mW) of the reproducing (reading) laser light.
  • the recording signal includes the information signal
  • the beginning and end portions include dummy data such as a repetition of a 4Tw mark and a 4Tw space, for example.
  • the VFO is also included at the beginning.
  • the information is rewritten with new information. That is, overwriting with a single substantially circular light spot is possible.
  • the recorded information is irradiated by irradiating continuous light of the intermediate power level (3 mW) of the power-modulated recording laser light or a power close to the intermediate power level (3 mW). Erase once, and then between the bottom power level (0.5 mW) and high power level (7 mW) or the intermediate power level (3 mW) and high power level (7 mW) in the next rotation.
  • recording may be performed by irradiating a laser beam whose power is modulated according to the information signal.
  • the previously written information is less likely to be erased. Therefore, rewriting when the linear velocity is doubled becomes easy.
  • DC light was applied to the information recording medium (disk A) shown in FIG. 1 having the cooling control layer described in this example and the conventional information recording medium (disk B) shown in FIG. 2 having no cooling control layer. Comparing the erase ratios (DC erase ratios) for disk A, disk A had an erase ratio of 27 dB, but disk B had a smaller erase ratio of 15 dB.
  • the DC erasure ratio the shortest recording signal (3 Tw) was recorded, and then DC light was irradiated to measure the change in the 3 Tw signal recorded first. If the erasing ratio is small, the overerased portion will become large during overwriting, causing an increase in jitter. Therefore, it is preferable that the DC erase ratio is large.
  • the reason why the DC erasure ratio of the disk A was increased was that the cooling rate of the recording film was controlled by providing the cooling control layer, and the time for which the recording film was held at the crystallization temperature could be increased.
  • the effect of providing the cooling control layer is particularly effective when recording is performed with a short wavelength light source such as a blue laser. (Thermal conductivity of the cooling control layer)
  • the thermal conductivity of the upper protective layer is around 0.7 W / m-k (0.5 to 2 W / m * k) because 48 dB or more is required to secure C / N at a practical level
  • the thermal conductivity of the cooling control layer is preferably larger than that of the upper protective layer by 0.1 WZm ⁇ k or more.
  • the CZN is required to be 49 dB or more, so the thermal conductivity of the cooling control layer is 0.13 W / m * lower than that of the upper protective layer. More preferably, it is larger than k.
  • the thermal conductivity of the upper protective layer was less than 0.5 W / m ⁇ k, heat hardly escaped, and the reflectivity fluctuated during rewriting of 100,000 times or more.
  • the thermal conductivity of the upper protective layer was greater than 2 WZ m ⁇ k, the recording sensitivity was reduced by 20%.
  • the cooling rate of heat must be reduced during erasing in order to improve the erasing characteristics.
  • a cooling control layer is provided between the reflective layer and the upper protective layer, which have high thermal conductivity, but the cooling rate is too low. Therefore, by controlling the thermal conductivity and the film thickness of the cooling control layer so that the cooling rate becomes appropriate, a medium having both good erasing characteristics and good recording characteristics can be obtained.
  • the film thickness d 5 (nm) of the film used for the cooling control layers 5 and 5 ′ and the film thickness d 4 (nm) of the film used for the upper protective layers 4 and 4 ′ were changed.
  • the DC elimination ratio was measured as follows, and the result was as follows (see Fig. 9).
  • the number of targets and the number of vacuum chambers required for sputtering the upper protective layer and the cooling control layer are also shown. As the film thickness increases, the film formation time becomes longer. Therefore, the film formation time is doubled by dividing the process into four or more steps and providing four or more vacuum chambers for sputtering.
  • the total thickness of the cooling control layer and the upper protective layer is preferably 60 nm or more in order to secure an erasing ratio of 20 dB or more, which is a practical level of erasing ratio, and at a level including a margin of power fluctuation. In terms of securing a certain erasing ratio of 30 dB, it is more preferable that the thickness be 90 nm or more.
  • the total thickness of the cooling control layer and the upper protective layer is preferably 240 nm or less, and the number of vacuum chambers is two or less. It is more preferable that the thickness be equal to or less than 144 nm.
  • the thickness of the cooling control layer is less than 10 nm, CZN decreased due to recrystallization.
  • the thickness of the upper protective layer was less than 10 nm, the protective effect of the recording film was lost, and the number of rewritable times was reduced by one digit or more.
  • the film thickness d4 of the film used for the upper protective layers 4 and 4 ' was fixed at 80 nm, and the film thickness d5 of the film used for the cooling control layers 5 and 5' was changed.
  • the DC erasure ratio was measured in the same manner, and the result was as follows. The number of targets and the number of vacuum chambers required for sputtering the upper protective layer and the cooling control layer are also shown.
  • the thickness of the cooling control layer is preferably 10 nm or more.
  • the thickness of the cooling control layer was less than 10 nm, C / N decreased due to recrystallization.
  • the film thickness d4 of the films used for the upper protective layers 4 and 4 'in this example was fixed at 1 O nm, and the film thickness d5 of the films used for the cooling control layers 5 and 5' was changed.
  • the result was as follows.
  • the number of targets and the number of vacuum chambers required for sputtering the upper protective layer and the cooling control layer are shown.
  • the thickness of the cooling control layer is preferably 230 nm or less.
  • the thickness of the upper protective layer is less than 10 nm, the protective effect of the recording film is lost, and the number of rewritable times is reduced. Has dropped by more than an order of magnitude.
  • the lower protective layer 2 (Zn S) 80 (S i O 2) 2.
  • (ZnS) 8 of the lower protective layer 2 having a two-layer structure.
  • the material in place of (S i O 2) 20, obtained by changing the mixing ratio of Z n S and S i 0 2 is preferred.
  • ZnS has a large sputter rate, and if ZnS occupies 60 m 0 1% or more, the film formation time can be shortened. The combination of high sputter rate and good chemical stability of oxide / nitride are combined. Other sulfides and selenides also showed characteristics similar to ZnS.
  • Elemental ratio in these compounds for example, the ratio of oxide or metal in sulfide element and oxygen element or sulfur element, A l 2 0 3, Y 2 O 3, L a 2 ⁇ 3 »2: 3, S i 0 2, Z r O 2, G e O 2 is 1: 2, T a 2 0 5 is 2: 5, Zn S 1: is preferably close to the ratio or take J of 1, from the ratio The same effect can be obtained even if it is off.
  • the deviation of the amount of the metal element be 10 atomic% or less, for example, the ratio of S i O 2 to ⁇ 10 atomic% or less in Si amount. If the deviation is 10 atomic% or more, the optical characteristics change, and the modulation factor is 10%. It fell above.
  • the material is preferably 90% or more of the total number of atoms in the lower protective layer.
  • the amount of impurities other than the above materials became 10 atomic% or more, the number of rewritable times became 1/2 or less, and the rewriting characteristics were deteriorated.
  • the extinction coefficient k of the lower protective layer used in this embodiment is preferably 0 or close to 0. Further, when the extinction coefficient k is k ⁇ 0.01 at a film thickness of 80% or more of the material of the lower protective layer, a decrease in contrast can be suppressed to 2% or less, which is preferable.
  • the lower protective layer be at least 2 layers, when the lower protective layer material of the recording film side C r 2 0 3, Zn into the recording film when a large number of times of rewriting, can suppress the diffusion of S, it is rewriting characteristics are good Wakata.
  • the C r 2 0 replaces 3 material of the lower protective layer material of the recording film side, S I_ ⁇ 2 to C r 2 ⁇ 3, T a 2 0 5, A l 2 O 3, Z r 0 2 - Y 2 A mixture obtained by mixing O 3 is preferable.
  • C o theta or Ge O 2, N i 0, mixtures thereof and C r 2 ⁇ 3 are preferred. These oxides have a small extinction coefficient k and very low absorption in the lower interface layer. Therefore, there is an advantage that the degree of modulation can be kept large.
  • a 1 N, BN, Cr N, Cr 2 N, Ge N, Hf N, Si 3 N 4 , A 1 -Si 1 N-based material (for example, A 1 Si N 2 ), Nitrides such as Si—N-based materials, Si—0-N-based materials, and TaN, TiN, and ZrN are more preferable because they have a long storage life and are resistant to changes in external temperature. Even if the recording film composition contains nitrogen or a material having a composition close thereto, the adhesive strength is improved.
  • the thickness is preferably 25 nm or less, and more preferably 10 nm or less. About 2 nm or more was able to form a uniform film, and 5 nm or more was even better. Accordingly, it is preferable that the thickness of the lower protective layer on the recording film side be 2 to 25 nm, because the recording-reproducing characteristics are better.
  • the recording film 3 is formed of Ge 5 Sb 2 Te 8 .
  • the refractive index of this recording film at the reproduction wavelength is 2.0 in the crystalline state and 2.6 in the amorphous state, which is smaller in the crystalline state.
  • Ag 3 Ge 3 is used as a material of the recording film 3 in place of Ge 5 Sb 2 Te 8 .
  • Different ones are preferable because the degree of modulation is large.
  • the added amount of Ag or Cr is preferably at least 2 atomic% and at most 10 atomic%.
  • overwriting is also possible with 06-313-cho 6 series materials to which 88 has been added.
  • Elements to be added to the recording film instead of Ag include Cr, W, Mo, Pt, Co, Ni, Pd, Si, Au, Cu, V, Mn, Fe, Ti, The overwrite characteristics were found to be good even when replaced with at least one of Bi. In all of these recording film materials, the refractive index at the reproduction wavelength is smaller in the crystalline state than in the amorphous state.
  • the jitter ( ⁇ / Tw) after 10 times of rewriting and 100,000 times of rewriting was measured by changing the film thickness of the recording films 3 and 3 ′.
  • the value with the worse jitter of the leading edge or trailing edge (%) after rewriting 10 times, and the jitter value (%) of the leading edge after 10,000 rewritings showed that.
  • the recording film thickness is 4 nm or more and 25 nm or less because the jitter can be reduced to 20% or less.
  • the upper protective layer 4 was formed by Z n S- S i 0 2.
  • Elemental ratio in these compounds for example, the ratio of oxide or metal in the sulfide elemental oxygen element or sulfur element, A 1 2 0 3, Y 2 0 3, L a 2 0 3 is 2: 3, S i ⁇ 2, Z r O 2, G e 0 2 is 1: 2, T a 2 O 5 3 ⁇ 42: 5, Zn S is 1: 1 but is preferably close to the ratio or take trough cormorants ratio from the ratio The same effect can be obtained even if it is off.
  • a 1 _0 is A 1 and a ratio rate of O is A 1 2 O 3 Sat 1 A 1 value from 0 atomic 0/0 or less
  • S i-0 is a S i 0
  • the deviation of the amount of the metal element be 10 atomic% or less, for example, the ratio of S i O 2 to the amount of Si is ⁇ 10 atomic% or less. 10 atoms. If the deviation is more than / 0 , the optical characteristics change, and the degree of modulation is reduced by 10% or more.
  • the material is preferably 90% or more of the total number of atoms in the upper protective layer.
  • the amount of impurities other than the above-mentioned materials was 10 atomic% or more, the number of rewritable times became 12 or less, and the rewriting characteristics were deteriorated.
  • the upper protective layer into two or more layers, when the upper protective layer material of the recording film side C r 2 0 3, Zn into the recording film when a large number of times of rewriting, can suppress the diffusion of S, that the rewriting characteristic becomes good all right.
  • an Ag ⁇ P diCU i film was used for the reflection layer 6.
  • a material of the other reflective layer a material mainly composed of an Ag alloy, such as Ag—Pt or Ag—Au, is preferable. Ag can also be used. When the content of elements other than Ag in the Ag alloy is in the range of 0.5 atomic% to 4 atomic%, the characteristics and bit error rate after many rewrites are improved, and 1 atomic% or more. It has been found that a good result is obtained in the range of 2 atomic% or less.
  • Zn 98 P d 2 film, Zn 98 P t 2 film, Zn 98 Cu 2 film, Z n 98 N i 2 film, Z n-P d film, Zn- P t film, Zn-Cu film, Zn- Ni films have the advantage of lower costs than Ag-based materials. Zn can also be used. ! ! In the alloy! ! If the content of other elements is in the range of 0.5 atomic% to 4 atomic%, the characteristics and bit error rate during multiple rewrites are improved, and 1 atomic% to 2 atomic%. It was found that the range was better.
  • the reflection layer is made of a metal element, a metalloid element, an alloy thereof, or a mixture.
  • those with high reflectivity such as Ag, A1, Al alloy, Ag alloy, etc.
  • Alloys have higher adhesive strength than single substances.
  • the content of elements other than A1, Ag, etc., which are the main components is in the range of 0.5 atomic% to 5 atomic% as in the case of the Ag alloy
  • the contrast ratio is large and the adhesive strength is also high. It was large and good. In the range of 1 atomic% or more and 2 atomic% or less, it was better. Comparing the reflectivity near the wavelength of 400 nm, Ag or Ag alloy is about 95%, and A1 and A1 alloy are about 92%. Ag type is larger, but material cost is higher. Following these materials, Zn and Zn alloys were approximately 89%, and Pt and Pt alloys were approximately 65%, with high reflectivity at short wavelengths, resulting in a large contrast.
  • the material is preferably 95% or more of the total number of atoms in the reflective layer.
  • the amount of impurities other than the above materials exceeded 5 atomic%, the number of rewritable times became 12 or less, and the rewriting characteristics deteriorated.
  • the thickness of the reflective layer is less than 2 Onm, the strength after weak rewriting is small, the thermal diffusion is small, and the recording film flows easily. Therefore, the jitter after rewriting 10,000 times is more than 15%. At 30 nm, it can be reduced to 15%.
  • the thickness of the reflective layer is greater than 200 nm, the time required to fabricate each reflective layer is longer, the formation time is doubled, such as dividing the process into two or more steps or providing two or more vacuum chambers for sputtering. did.
  • the thickness of the reflective layer was 5 nm or less, the film was formed in an island shape, and noise increased.
  • the thickness of the reflective layer is preferably 5 nm or more and 200 nm or less in view of noise, jitter and formation time.
  • a polycarbonate base having a tracking groove directly on the surface is used.
  • the plate 1 is used, polyolefin, epoxy, acrylic resin, chemically strengthened glass having an ultraviolet curable resin layer formed on the surface may be used instead. Quartz or C a F may be used instead of the reinforced glass.
  • a substrate having a tracking groove is defined as having a depth equal to or greater than LZl 2 n '( ⁇ ' is the refractive index of the substrate material) when the recording wavelength is L.
  • This is a substrate with grooves.
  • the groove may be formed continuously in one round, or may be divided in the middle.
  • I 6 ⁇ ' the crosstalk was small and it was found to be preferable.
  • the cross erase was small.
  • the groove width may be different depending on the location.
  • a substrate having no groove, a sampler format substrate, a substrate using another tracking method, or another format may be used.
  • the substrate may have a format that allows recording / reproducing on both the groove and the land, or may have a format that allows recording on either one. If the track pitch is small, signal leakage from the adjacent track will be detected and noise will occur. Therefore, the track pitch is preferably 1 Z2 or more of the spot diameter (the area where the light intensity is lZe 2 ). .
  • the disk size is not limited to a diameter of 12 cm, but may be 13 cm, 8 cm, 3.5 inches, 2.5 inches, or other sizes.
  • the disk thickness is not limited to 0.6 mm, but may be other thicknesses such as 1.2 mm, 0.8 mm, 0.4 mm, and 0.1 mm.
  • two disk members are manufactured by exactly the same method, and the reflection layers 6, 6 'of the first and second disk members are bonded together via an adhesive layer.
  • a disk member having another configuration, a protection substrate, or the like may be used.
  • the bonding can be performed using an ultraviolet curable resin.
  • the bonding may be performed by another method.
  • the layers are stacked in reverse order from the reflective layer 6 side to the lower protective layer 2 on the substrate 14 with lands where the distance between the substrate surface and the contact surface with the film is short. Then, finally, the substrate 1 on the light incident side may be formed or bonded.
  • each layer is formed in the order of the lower protective layer, the recording film, and the upper protective layer from the substrate 1 on the light incident side.
  • the layers need not necessarily be formed and stacked in order from the light incident side.
  • an ultraviolet curable resin having a thickness of about 10 m is applied on the reflective layers 6, 6' of the first and second disk members.
  • the error rate can be further reduced.
  • two disk members are manufactured and bonded via the adhesive layer 7, but without bonding, the ultraviolet ray hardening is performed on the reflection layer 6 of the first disk member.
  • the resin may be applied to a thickness of about 10 / m or more. In the case of a disk member having no reflective layer 6, an ultraviolet curable resin may be applied on the uppermost layer. (Thickness and material of each layer)
  • Recording / reproducing characteristics can be improved by simply setting each of the thicknesses and materials of each layer to a single preferable range. However, the effect is further improved by combining the respective preferable ranges.
  • (ZnS) 8 having a film thickness of about 80 nm was formed on a polycarbonate substrate 1 having a diameter of 12 cm, a thickness of 0.6 mm, and a tracking groove on the surface.
  • Lower protective layer 2 composed of 20 films and a Cr 2 ⁇ 3 film with a thickness of about 5 nm, Ge 5 Sb 2 Te 8 recording film 3 with a thickness of about 18 nm, film
  • An upper protective layer 4 consisting of a Cr 2 O 3 film with a thickness of about 5 nm and a (ZnS) so (Sio 2 ) 20 film with a thickness of about 10 nm.
  • the second disk member is made of (ZnS) 8 with a film thickness of about 80 nm on the polycarbonate substrate 1 '.
  • disks C2 to C6 were prepared in which only the composition of the cooling control layers 5, 5 'was changed.
  • the reflectance difference AR was calculated by the following equation.
  • the value of the refractive index n is that of the reproduction wavelength (410 nm).
  • the reflectance difference AR can be increased to 1.1 1, and the SZN ratio at the time of reproduction is about 1 d ⁇ It turned out that it is more preferable for improvement. Further, when a material having a refractive index of the cooling control layer larger than that of the upper protective layer as in the present embodiment was used, the mechanical strength was high, so that the change in reflectance after many rewrites was small.
  • (Cr 2 O 3 ) 4 was used for the cooling control layers 5 and 5 ′ in this example.
  • Film is had as the (S i C) y (S i 0 2) material to replace 10 y film, it is preferable that changed C r 2 0 3 and the mixing ratio of S i ⁇ 2.
  • n of the cooling control layer is the difference between the n of the upper protective layer 0 It is preferably at least 1. Elemental ratio in these compounds, for example, the ratio of the metal elemental oxygen element or sulfur element in the oxide or sulfide, A 1 2 0 3, Y 2 0 3, L a 2 0 3 is 2: 3, S i O 2, Z r 0 2, Ge_ ⁇ 2 ttl: 2, T a 2 O 5 is 2: 5, Zn S is 1: is preferably close to the ratio or take 1 trough cormorants ratio.
  • a 10 is the ratio of A 1 and O from A 1 2 ⁇ 3 10 atoms 0/0 or less
  • S i ten is S i and O
  • the deviation of the amount of the metal element be 10 atomic% or less, such as the ratio of S i 0 2 to Si 10 atomic% or less in the Si amount.
  • a deviation of 10 atomic% or more causes a change in optical characteristics, resulting in a decrease in reflectivity of 10% or more.
  • a mixture containing Cr 2 ⁇ 3 and Cr 2 O 3 was preferred because of its high adhesive strength and high thermal stability. Then, a mixture comprising a C 0 2 0 3 and C 0 2 0 3 is greater adhesive strength. If the melting point of the compound and / or metal in the material of the cooling control layer is higher than the melting point of the recording film (about 60 CTC), the jitter rise after 10,000 rewrites can be suppressed to 5% or less. When the melting points of both are 600 ° C. or more, it is more preferable because the melting point can be suppressed to 3% or less.
  • the impurity element in the cooling control layer exceeded 2 atom ° / 0 of the component of the cooling control layer, the jitter of the leading edge or the trailing edge after 10 rewrites exceeded 15%. Furthermore, it was found that when the impurity element exceeds 5 atomic%, the jitter becomes 18% or more. Therefore, it is preferable that the impurity element in the cooling control layer is 5 atomic% or less of the component of the cooling control layer because the deterioration of the rewriting characteristics can be reduced. It is more preferable that the content be 2 atomic% or less.
  • the second disk member is (ZnS) 8 with a film thickness of about 80 nm on a poly-carbonate substrate 1 '.
  • Te (C r 2 ⁇ 3) x (S I_ ⁇ 2) 100 _ x film odor was created made the 1 X 0, 30, 35, 40 , 45 and the medium (disc D 2 ⁇ D 6) .
  • the manufactured information recording medium disks D1 to D6
  • a recording signal of 1 l Tw was recorded, and the reflectance level Rc in the crystalline state and the reflectance level Ra in the amorphous state were measured.
  • Difference AR was determined. Since the disk of the present example has a higher reflectance level in the crystalline state, the reflectance difference AR was calculated by the following equation.
  • the refractive index of the cooling control layer changed, and the reflectance difference ⁇ (%) changed as shown in the table below. If the reflectance difference is small, the SZN ratio (signal-to-noise ratio) will be small and jitter will increase, so a larger reflectance difference is preferred.
  • the reflectivity difference AR changes the reflectance difference AR.
  • the difference ⁇ 1 between the refractive index of the cooling control layer and the upper protective layer is 0.1 or more, the reflectivity difference can be 1.06 times that when ⁇ 1 is zero. It is more preferable because the S / N ratio of the hologram is improved by about 0.5 dB, and if the ratio of 111 is 0.15 or more, the reflectivity difference can be 1.1 times, and the SZN ratio at the time of reproduction is about 1 dB It turned out that it is more preferable because it becomes better.
  • the cooling control layer (C r 2 0 3) 45 (S i O 2) 55
  • the recording sensitivity was higher than when used.
  • S i-0- N based material As the material having a smaller refractive index than the upper protective layer, S i-0- N based material, S i 0 2, S i O, T i 0 2, A 1 2 0 3, Y 2 0 3, C e 0 2, Ge O, G e O a, P b 0, S n O, S nO 2, B e O, B i. O 3, T e 0 2, W0 2, WO 3,
  • a disk-shaped information recording medium whose cross-sectional structure is schematically shown in FIG. 4 was produced.
  • a (Cr 2 O 3 ) 45 (S i) film with a thickness of about 15 nm was placed on a polycarbonate substrate 1 having a diameter of 12 cm, a thickness of 0.6 mm and a groove for tracking on the surface.
  • a lower protective layer 2 consisting of C r 2 0 3 film of about 5 nm, G e 5 S b 2 T e 8 recording film 3 thickness of about 1 8 nm, A Cr 2 O 3 film with a thickness of about 5 nm and (Zn S) 8 with a thickness of about 1 O nm
  • a cooling control layer 5 composed of a film and a reflective layer 6 composed of an Ag 98 PdCui film having a thickness of about 80 nm were sequentially formed.
  • the formation of the laminated film was performed by a magnetron sputtering apparatus.
  • a first disk member was obtained.
  • a second disk member having the same configuration as the first disk member was obtained in exactly the same manner.
  • the second disk member is composed of a (Cr 2 ⁇ 3 ) 45 (Sio 2 ) 55 film having a film thickness of about 15 nm and a contrast magnifying layer 8 ′ on a poly-carbonate substrate 1 ′.
  • (Zn S) 8 After laminating a lower protective layer 2 ′ made of (S i O 2 ) 20 film and Cr 2 O 3 having a thickness of about 5 nm, a Ge 5 Sb 2 Te 8 recording film 3 ′ is formed to a thickness of about 18 nm. , having a thickness of about 5 nm C r 2 ⁇ 3 film and the film thickness of about 1 O nm (Zn S) 80 (S i O 2) 2.
  • Upper protective layer 4 made of film ', thickness of about 90 nm (C r 2 O 3 ) 4.
  • disk-shaped information recording media (disks E2 to E6) in which the compositions of the contrast enhancement layers 8 and 8 'were changed were manufactured.
  • a recording signal of 11 Tw was recorded on this information recording medium (disks E1 to E6), and the reflectivity level in the crystalline state and the reflectivity level in the amorphous state were measured, and the reflectivity difference was determined. . Since the reflectivity level of the disk of this example in the crystalline state is larger, the reflectivity difference was calculated from the following equation.
  • the composition of the contrast-enlarging layer changed the refractive index of the contrast-enlarging layer, and the reflectance difference (%) changed as shown in the table below. If the reflectance difference is small, the signal-to-noise ratio (signal-to-noise ratio) will decrease, and jitter will increase. R is preferably larger.
  • the reflectance difference ⁇ R can be increased by changing the refractive index of the contrast enhancement layer. If the refractive index difference ⁇ 2 between the contrast enhancement layer and the lower protection layer is 0.1 or more, there is no contrast enhancement layer, and the reflectance difference between the upper protection layer and the cooling control layer is equal to that of the disc C 1. 1. It is preferable because it can be made 11 times and the SZN ratio at the time of reproduction is improved by about 1 d d compared to the disc C1. Also, if ⁇ 2 is 0.15 or more, the reflectivity difference can be 1.17 times higher than that of disk C 1, and the SZN ratio during playback is 1.4 dB higher than that of disk C 1. It turned out to be more favorable. Also, when a material having a large refractive index in the contrast enhancement layer was used for the lower protective layer, the change in reflectance during multi-time rewriting was small due to the high mechanical strength.
  • the material to replace material used for contrast expansion layer 8, 8 'in this embodiment Z n S, S i- N-based materials, S i-O-N-based materials, S i 0 2, S i O, T i O 2, A 1 2 O 3, Y 2 O 3, C e 0 2, L a 2 0 3, I n 2 O 3, G e O, G e 0 2, Pb O, S nO, S n 0 2, B e O, B i 2 O 3, T e O WO ,, WO S c 2 O 3: T a 2 0 5, Z r O 2, C u 2 0, MgO, V 2 0 3, Nb 2 0 3, C o 2 0 3, C o O,
  • Elemental ratio in these compounds for example, the ratio of oxide or metal in the sulfide elemental oxygen element or sulfur element, A 1 2 0 3, Y 2 O 3, L a 2 0 3 is 2: 3, S i It is preferable that 0 2 , ZrO 2 , and GeO 2 have a ratio of 1: 2, Ta 2 O 52 2: 5, and ZnS have a ratio of 1: 1 or close to that ratio. The same effect can be obtained even if it is off.
  • a 1-0 has a ratio of A 1 to O of A 1 2 O 3 from A 1 2 O 3 which is less than 10 atomic% in soil
  • S i— O has S i and O the percentage is S i 0 2 from below ⁇ 1 0 atomic% in S i amount of the deviation of the metal element content is preferably 1 0 atomic% or less.
  • a deviation of 10 atomic% or more causes a change in the optical characteristics, resulting in a decrease in reflectance difference of 10% or more.
  • mixtures of C r 2 ⁇ 3 and C r 2 0 3 has a large adhesive strength, were preferred for higher thermal weaker qualitative. Then, a mixture of C 0 2 0 3 and C 0 2 0 3 is greater adhesive strength. If the melting point of the compound in the contrast enhancement layer material and Z or the simple substance of metal is higher than the melting point of the recording film (about 600 ° C), the increase in jitter after 10,000 rewrites can be suppressed to 5% or less. When the melting points of both are 600 ° C. or more, it is more preferable because the melting point can be suppressed to 3% or less.
  • the impurity element in the contrast enhancement layer exceeded 2 atomic% of the components of the contrast enhancement layer, the jitter of the leading edge or trailing edge after 10 times rewriting exceeded 15%. Further, it was found that when the impurity element exceeds 5 atomic%, the jitter becomes 18% or more. Therefore, when the impurity element in the contrast enhancement layer is 5 atomic% or less of the component of the contrast enhancement layer, the deterioration of the rewriting characteristics can be reduced. preferable. More preferably, it is at most 2 atomic%.
  • a contrast enhancement layer 8 consisting of a SiO 2 film with a thickness of about 6 nm, a film Thickness of about 70 11111 (2 11 3) 8 . (3 10 2) 20 layer and a thickness of about five hundred eleven thousand one hundred eleven 0 r 2 ⁇ lower lower protective layer 2 after the lamination of three of, G e 5 S b 2 T e 8 recording film 3 thickness of about 1 8 nm, film A Cr 2 O 3 film with a thickness of about 5 nm and (ZnS) 8 with a thickness of about 10 nm.
  • the second disk member is composed of a contrast enhancement layer 8 ′ composed of a SiO 2 film having a thickness of about 6 O nm and a (ZnS) 8 having a thickness of about 7 O nm on a polycarbonate substrate 1 ′. .
  • a recording signal of 11 Tw was recorded on these information recording media (disks F1 to F5), and the reflectivity level in the crystalline state and the reflectivity level in the amorphous state were measured, and the reflectivity difference AR was obtained. .
  • the reflectivity level in the crystalline state was larger than the reflectivity level in the amorphous state, so the reflectivity difference was calculated by the following equation.
  • the refractive index of the contrast enhancement layer changed, and the reflectance difference (%) changed as shown in the table below. If the reflectance difference is small, the SZN ratio (signal-to-noise ratio) becomes small and jitter increases. Therefore, it is preferable that the reflectance difference is large.
  • the values of the refractive index are those of the reproduction wavelength (410 nm).
  • the reflectance difference ⁇ R can be increased by changing the refractive index of the contrast enhancement layer.
  • the refractive index difference ⁇ 2 between the contrast enhancement layer and the lower protective layer is 0.1 or more, the reflectance is lower than that of the disc C 1 in which the contrast enhancement layer is not provided, and the upper protective layer and the cooling control layer have the same refractive index.
  • the difference can be made 1.1 times and the S / N ratio at the time of reproduction is improved by about 1 d ⁇ compared to the disc C 1.
  • 112 is 0.15 or more, the difference in reflectance can be 1.17 times that of disk C1, and the S / N ratio during playback improves by about 1.4 dB compared to disk C1.
  • Example 1 an information recording medium was manufactured in which the composition of the films used for the cooling control layers 5 and 5 ′ and the thickness of each layer were changed.
  • Boneito substrate 1 having grooves for tracking on the surface diameter 1 2 cm, a thickness of 0. 6 mm, thickness of about 1 00 nm (Z n S) 80 (S i 0 2) 20 after stacking a lower protective layer 2 made of film and the film thickness of about 5 nm C r 2 0 3, thickness of about 1 0 nm for G e 5 S b 2 T e 8 from consisting recording film 3, a thickness of about 5 nm C r 2 O 3 film and the film thickness of about 40 nm of (Zn S) 80 (S i O 2) 20 upper protective layer 4 made of film, the film thickness of about 60 nm (C 1 "2 0 3) 45 ( 8 10 2 )
  • a cooling control layer 5 consisting of 55 films and a reflective layer 6 consisting of an Ag 98 Pd Cu film with a film thickness of about 80 nm were sequentially formed, and the laminated film was formed by a magnetron-sputtering apparatus.
  • the second disk member is made of (ZnS) 8 having a thickness of about 100 nm on the polycarbonate substrate 1 '. (S i 0 2) 20 layer and the film thickness after stacking a lower protective layer 2 'made of C r 2 0 3 of about 5 nm, a film thickness of about 1 O nm of Ge 5 Sb 2 T e 8 recording film 3 consisting of ', ⁇ a thickness of about 511 111 1-2 0 3 film and the film thickness of about 4,011,111 of (Zn S) 8.
  • disk G1 a disk-shaped information recording medium
  • disks G2 to G6 in which only the compositions of the cooling control layers 5 and 5 'were changed were manufactured.
  • a recording signal of 11 Tw is recorded on these information recording media (disks G1 to G6),
  • the reflectance level Rc in the crystalline state and the reflectance level Ra in the amorphous state were measured, and the reflectance difference AR was determined. Since the reflectivity level of the disk of the present example was higher in the amorphous state, the reflectivity difference was calculated by the following equation.
  • the refractive index of the cooling control layer changed, and the reflectance difference ⁇ (%) changed as follows. If the reflectance difference is small, the S / N ratio (signal-to-noise ratio) will be small, and jitter will increase. Therefore, it is preferable that the reflectance difference is large.
  • the value of the refractive index n is that of the reproduction wavelength (410 nm).
  • the ratio A cZA a of the absorptivity level Ac in the crystalline state and the absorptivity A a in the amorphous state in the recording film is as large as 1.3,
  • the reproduction signal distortion was smaller than that of the disc described in Example 1.
  • Elemental ratio in these compounds for example, the ratio of the metal element and oxygen element and sulfur element in oxide or sulfide, A 1 2 0 3, Y 2 0 3, L a 2 0 3 is 2: 3, S i O 2 , Z r O 2, Ge O 2 is 1: 2, T a 2 O 2: 5, Zn S is 1: 1 but is preferably close to the ratio or take trough cormorants ratio, be outside of the ratio Similar effects are obtained.
  • a 1- ⁇ is A 1 and by A 1 weight ratio from A 1 2 O 3 of 0 Sat 10 atoms 0/0 or less
  • S i- ⁇ is a S i the percentage is S i 0 ⁇ 2 from at S i of 1 0 atomic% or less, such as 0, displacement of the metal element amount is preferably 1 0 atomic% or less. If the deviation is more than 10 atomic%, the optical characteristics change, and the difference in reflectance is reduced by more than 10%.
  • the content of the impurity element in the cooling control layer is 5 atomic% or less of the component of the cooling control layer because the deterioration of the rewriting characteristics can be reduced. It is more preferable that the content be 2 atomic% or less.
  • Information recording medium in the cooling control layer 5 of Example 1, 5 was used in '(C r 2 0 3) 45 (S i O 2) 55 film of 01 "2 0 3 and the mixing ratio and film 8 i O 2 An information recording medium with a different thickness was manufactured.
  • (ZnS) 8 having a thickness of about 100 nm was formed on a polycarbonate substrate 1 having a diameter of 12 cm, a thickness of 0.6 mm and a tracking groove on the surface.
  • the recording film made of Ge 5 Sb 2 Te 8 with a thickness of about 10 nm 3.
  • Cr 2 O 3 film with a thickness of about 5 nm and (Zn S) 8 with a thickness of about 40 nm.
  • the second disk member is made of (ZnS) 8 with a thickness of about 100 nm on a poly-carbonate substrate 1 '. (S I_ ⁇ 2) 20 layer and the film thickness after stacking a lower protective layer 2 'made of C r 2 O 3 of about 5 nm, a film thickness of about 1 O nm of Ge 5 Sb 2 T e 8 recording film 3 consisting of ', having a thickness of about 5 nm C r 2 ⁇ 3 film and the film thickness of about 40 nm (Zn S) 8.
  • a recording signal of 1 l Tw was recorded on the information recording medium (disks HI to H6) of the present embodiment, and the reflectivity level in the crystalline state and the reflectivity level in the amorphous state were measured. I asked. Since the disk of this example has a higher reflectance level in the amorphous state, the reflectance difference AR was calculated by the following equation.
  • the refractive index of the cooling control layer changed, and the reflectance difference (%) changed as shown in the table below. If the reflectance difference is small, the SZN ratio (signal-to-noise ratio) will decrease and jitter will increase. Therefore, it is preferable that the reflectance difference AR be large.
  • An information recording medium having the same laminated structure as in Example 1 was manufactured except for the group width of the substrate.
  • a diameter of 12 cm, a thickness of 0.6 mm, a track pitch of 0.34 ⁇ on the surface, the ratio of groove width (W sg) to land width (W s 1) W s W sg / W s 1 1.0, 1.09, 1.13, 1.17, 1.21, 1.26, 1.34, Poly-polycarbonate substrate with a 50 nm deep groove for tracking 1
  • the groove width (W sg) and land width (W s 1) are measured values at a height of 1 to 2 of the group depth hs.
  • FIG. 5 shows a schematic cross-sectional view of the substrate portion.
  • a second disk member having the same configuration as the first disk member was obtained in exactly the same manner.
  • the second disk member is provided on the polycarbonate substrate 1 ′, (211 3) 8 with a film thickness of about 80 11111.
  • the groove-to-land ratio Ws of the substrate was changed as follows for J1 to J7, and the groove-to-land ratio was changed for the disk (K1 to K7) whose lower protective layer thickness was changed to 170 nm.
  • Ws groove-land ratio
  • S S gZS1
  • the signal level ratio S is preferably close to 1. That is, when the group-land ratio Ws and the thickness d 1 (nm) of the lower protective layer satisfy the following relationship, the signal level ratio S can be close to 1, which is preferable. In the following range, the signal level ratio S can be set to 0.8 or more and 1.2 or less.
  • the coefficient k 1 is in the range of 0.001 15 ⁇ k l ⁇ 0.0025.
  • the signal level ratio S can be set to 0.9 or more and 1.1 or less.
  • An information recording medium having the same laminated structure as that of Example 3 was prepared except for the group width of the substrate.
  • the groove width (Ws g) and land width (Ws 1) ratio Ws Ws g / / Ws 1 is different, and the groove depth Prepare 7 types of polycarbonate substrate 1 with 5 Om tracking groove.
  • the group width (W sg) and land width (W s 1) are measurements at a height of 1 to 2 of the group depth hs.
  • FIG. 6 shows a schematic cross-sectional view of the substrate portion. On each substrate 1, (Cr 2 ⁇ 3 ) 4 with a thickness of about 15 nm.
  • a cooling control layer 5 composed of a film and a reflective layer 6 composed of an Ag 98 PdCu 1 film having a thickness of about 80 nm were sequentially formed.
  • the formation of the laminated film was performed by a magnetron sputtering apparatus. Thus, a first disk member was obtained.
  • a second disk member having the same configuration as the first disk member was obtained in exactly the same manner.
  • the second disc member said polycarbonate Nei on preparative substrate 1 ', the thickness of about 1 5 nm (C r 2 O 3) 4.
  • (S i O 2) 60 contrast spreading layer 8 made of film ', thickness of about 8 0 11111 (11 8) 8.
  • the first disk member and the second disk member are bonded to each other with the respective reflective layers 6 and 6 ′ via an adhesive layer 7, and the disk-shaped information recording media (disks L1 to L7) are assembled. Obtained.
  • the signal level ratio S is preferably close to 1. That is, it was found that when the group / land ratio Ws and the total thickness d 2 (nm) of the lower protective layer thickness and the contrast enhancement layer satisfy the following relationship, the signal level ratio can be close to 1, which is preferable. In the following range, the signal level ratio S can be set to 0.8 or more and 1.2 or less.
  • the coefficient k2 is in the range of 0.001 15 ⁇ k2 ⁇ 0.0025.
  • the signal level ratio S can be set to 0.9 or more and 1.1 or less.
  • the signal level ratio S can be close to 1. This is not limited to a substrate with a track pitch of 0.34 ⁇ , especially
  • a disc having the same laminated structure as in Example 1 was produced except for the substrate and the lamination order. It has a diameter of 12 cm, a thickness of 0.6 mm, a tracking groove on the surface with a track pitch of 0.34 ⁇ , and a tracking groove.The land closer to the light-incident side substrate surface and contact surface becomes the land. Seven types of polycarbonate substrates 14 were prepared. FIG. 7 shows a schematic cross-sectional view of the substrate portion. A film thickness of about 80! ! ! ! ! No eight ⁇ ? ⁇ !
  • An upper protective layer 4 made of a film, a recording film 3 made of Ge 5 Sb 2 Te 8 having a thickness of about 18 nm, and (ZnS) 8 having a thickness of about 80 nm.
  • a lower protective layer 2 composed of (S i 0 2 ) 20 film and Cr 2 O 3 having a thickness of about 5 nm was sequentially formed. The formation of the laminated film was performed by a magnetron-sputtering apparatus. Thereafter, the disk member and the substrate 1 on the light incident side were bonded together via an adhesive layer 7, to obtain disk-shaped information recording media (disks N1 to N7).
  • the signal level ratio is preferably close to 1. That is, if the groove-land ratio Rs and the total thickness e (nm) of the reflective layer, the cooling control layer, and the upper protective layer satisfy the following relationship, the signal level ratio can be close to 1 and this is preferable. I understood. In the following range, the signal level ratio S can be set to 0.8 or more and 1.2 or less.
  • the coefficient J is in the range of 0.0005 ⁇ j ⁇ 0.0015.
  • an information recording medium having good recording / reproducing characteristics can be obtained.

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  • Optical Record Carriers And Manufacture Thereof (AREA)

Abstract

La présente invention concerne un support utile pour enregistrer de l'information à l'aide d'un laser bleu qui présente de bonnes caractéristiques d'enregistrement et de reproduction. Un substrat (1, 1') comporte un film mince d'enregistrement d'information qui fait office de film d'enregistrement (3, 3') sur lequel l'information est enregistrée sous forme d'un changement de la disposition des atomes provoqué par l'irradiation avec de la lumière. L'indice de réfraction de la phase amorphe du film d'enregistrement pour une longueur d'onde de reproduction est supérieur à celui de la phase cristalline. Une couche protectrice inférieure (2, 2') est formée entre le film d'enregistrement et le substrat. Une couche protectrice supérieure (4, 4') et une couche réfléchissante (6, 6') sont formées sur le film d'enregistrement sur le côté opposé au substrat. Une couche (5, 5') de régulation du refroidissement est formée entre la couche protectrice supérieure et la couche réfléchissante.
PCT/JP2000/004524 2000-07-06 2000-07-06 Support d'enregistrement d'information WO2002005275A1 (fr)

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PCT/JP2000/004524 WO2002005275A1 (fr) 2000-07-06 2000-07-06 Support d'enregistrement d'information
TW090108017A TW556170B (en) 2000-07-06 2001-04-03 Data recording medium

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PCT/JP2000/004524 WO2002005275A1 (fr) 2000-07-06 2000-07-06 Support d'enregistrement d'information

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7736715B2 (en) 2005-06-08 2010-06-15 Kabushiki Kaisha Toshiba Optical recording medium, and information recording/playback apparatus and method using the medium

Citations (6)

* Cited by examiner, † Cited by third party
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JPH09223332A (ja) * 1996-02-19 1997-08-26 Toray Ind Inc 光記録媒体
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