JPH03171445A - Production of information recording medium - Google Patents

Abstract

PURPOSE:To obtain the information recording medium which substantially obviates the deformation of an underlying layer at the time of data recording and decreases errors by providing the underlying layer on the surface of a substrate subjected to a sputter etching treatment and further providing a recording layer contg. Te which allows recording and/or reproducing of information on the underlying layer. CONSTITUTION:The surface on the side to be formed with the recording layer of the disk-shaped substrate made of a resin is subjected to the sputter etching treatment. The sputter etching treatment is called reverse sputtering as well and is preferably executed by a method of, for example, a glow discharge sputter etching. The underlying layer consisting of fluoroplastic is then provided by sputtering on the surface of the substrate subjected to the sputter etching treatment and the recording layer contg. the Te which allows the information and/or reproducing of the information by a laser beam is provided on the formed underlying layer. The layer thickness of the underlying layer consisting of the fluoroplastic is thin and the deformation of the underlying layer and the peeling thereof from the substrate at the time of data recording are obviated. The information recording medium which has the improved sensitivity and signal grade and is effective for recording and reproducing particularly at a low speed is formed with high productivity.

Description

[Detailed Description of the Invention] [Field of the Invention] The present invention provides an information recording medium that can be manufactured with high productivity, with almost no deformation of the underlying layer during data recording and fewer errors. Relating to a manufacturing method.

[Technical Background of the Invention] In recent years, information recording media that use high energy density beams such as laser light have been developed and put into practical use. This information recording medium is called an optical disk and can be used as a video disk, an audio disk, a large-capacity still image file, and a large-capacity computer disk memory.

The basic structure of such information recording media is a disk-shaped transparent substrate made of plastic, glass, etc., and a recording layer made of metal or semimetal such as Bi, Sn, In, Te, Se, etc. provided thereon. and has. Writing (recording!!) information on an optical disk is performed by, for example, irradiating the optical disk with a laser beam, and the irradiated portion of the recording layer absorbs the light and locally raises the temperature by -12, causing pits to form. Information is recorded by changing its optical properties through physical changes such as formation or chemical changes such as phase changes. Reading (reproducing) information from an optical disc is also performed by irradiating the optical disc with a laser beam, and the information is reproduced by detecting reflected or transmitted light that corresponds to changes in the optical characteristics of the recording layer. Ru. Laser beam irradiation for writing and reading information on the optical disc is usually performed at a predetermined position on the disc surface.

In such information recording media, in order to improve the recording sensitivity and reduce the degree of deterioration of the CN ratio of the read signal over time, fluorine and carbon made from a fluororesin are contained between the substrate and the recording layer. It has been proposed to form a base layer made of an organic compound (for example, Japanese Patent Application Laid-open No. 1983
-7348 Publication).

However, the underlayer described above has poor adhesion to the substrate, which can cause the recording layer to peel off or create holes in the underlayer when information is recorded, so it is difficult to further improve the sensitivity and signal quality of the information recording medium. In order to achieve this, it was necessary to increase the thickness of the underlying layer.

The base layer as described above is normally formed by sputtering fluororesin, but forming a thick base layer as described above using an expensive sputtering device reduces the productivity of the information recording medium. This results in a decrease in the cost and an increase in costs.

[Object of the Invention] The present invention provides improved sensitivity and signal quality without causing deformation or peeling of the underlayer from the substrate during data recording even when the thickness of the underlayer made of fluororesin is reduced. An object of the present invention is to provide a method for manufacturing an information recording medium that can be manufactured with high productivity.

[Summary of the Invention] The present invention involves sputter-etching the surface of a disk-shaped resin substrate on which the recording layer is to be formed, and sputtering a base layer made of a fluororesin onto the sputter-etched surface of the substrate. A method of manufacturing an information recording medium is provided, further comprising providing a recording layer containing Te on the underlayer, on which information can be recorded and/or reproduced by laser light.

Preferred embodiments of the method for manufacturing the information recording medium of the present invention are as follows.

1) The sputter etching treatment of the substrate is performed by ion beam sputter etching or glow discharge sputter etching. The method for manufacturing an information recording medium as described above, characterized in that it is carried out by a method of manufacturing an information recording medium.

2) The method for manufacturing the information recording medium, characterized in that the sputter etching treatment of the substrate is performed until the contact angle of the surface of the substrate to water decreases by 5 degrees or more.

3) The method for manufacturing the information recording medium described above, characterized in that the underlayer F is provided with a layer thickness of 100 to IOOOX, more preferably 200 to 600X.

4) The fluororesin is at least one selected from polytetrafluoroethylene, polyvinyl fluoride, polytrifluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polychlorotrifluoroethylene, and polycarbon monofluoride. The method for manufacturing the above-mentioned information recording medium, characterized in that it is made of resin.

5) The method for manufacturing the information recording medium, wherein the fluororesin is polytetrafluoroethylene.

6) The method for manufacturing the information recording medium, wherein the recording layer is a recording layer containing Te and Se.

7) The recording layer is S e a T e b M c
(However, 0.02≦a≦0.35, 0.50≦b≦0
．． 98, a value in the range of 0≦C≦0.45, and M is P
b% In, Ge, S, Sb, As, Bi% Sn% AL
L, Ga%TI, Zn, Cd, Au% Pt%Ag%C
The above-mentioned information recording medium has a composition represented by (representing at least one metal selected from u, Ni, Pd, Rh, Cr, Mo, W and Ta).

8) The method for producing the above-mentioned information recording medium, wherein the metal represented by Doki M is PB.

9) On the recording layer, silicon dioxide, tin oxide, magnesium fluoride, titanium oxide, Tea. (However, 1≦X≦
2) The method for manufacturing the above-mentioned information recording medium, which comprises laminating layers made of at least one material selected from zirconium oxide and zinc oxide.

10) TeOX (1.5≦X≦
2) The method for manufacturing the information recording medium described above, characterized by laminating layers consisting of the following.

[Detailed Description of the Invention] In the method for manufacturing an information recording medium of the present invention, first, the surface of the resin disk-shaped substrate on which the recording layer is to be formed is subjected to sputter etching treatment.

The substrate can be arbitrarily selected from various resin materials used as substrates for conventional information recording media. Examples of substrate materials include cell-cast polymethyl methacrylate, injection molded polymethyl methacrylate, and other acrylic resins from the viewpoint of substrate optical properties, flatness, workability, handling, stability over time, and manufacturing costs. Vinyl chloride resins such as vinyl chloride and vinyl chloride copolymers; epoxy network resins; polyesters such as polyethylene terephthalate; polycarbonates and amorphous polyolefins can be mentioned. Among these, preferred are polymethyl methacrylate, polycarbonate, epoxy resin, amorphous polyolefin and polyethylene terephthalate, with polycarbonate being particularly preferred.

Furthermore, pre-groups are provided on the substrate for the purpose of tracking groups, or pre-pits are provided for the purpose of forming unevenness representing information such as address signals.

The above sputter etching process is also called reverse sputter etching, and can be performed by, for example, ion beam sputter etching, glow discharge sputter etching, etc. In particular, in order to simplify the equipment, glow discharge sputter etching is It is preferable to carry out by the method.

The equipment and processing conditions used for the above-mentioned sputter etching process can be those normally used for conventional sputter etching processes, such as spatter equipment (e.g., ion beam spatter equipment, RF glow discharge spatter equipment, DC Glow discharge sputtering equipment, magnetron sputtering equipment, etc.) are used to apply power to the substrate side to generate a glow discharge, or an ion beam is introduced to the substrate side.

In the present invention, when performing sputter etching treatment by glow discharge sputter etching, 1 x 1
0-3 to 50 X 1 0-3 Torr pressure, 20
~200W power, Ar, N2, 02, Ne, Kr,
It is preferable to use a gas such as Xe or a mixture thereof.

In the present invention, it is preferable that the sputter etching treatment of the substrate is performed until the contact angle of the surface of the substrate to water decreases by 5 degrees or more.

In the present invention, a base layer made of a fluororesin is then provided by sputtering on the surface of the substrate subjected to the sputter etching process as described above.

Examples of the fluororesin that can be used to form the base layer include polytetrafluoroethylene, polyvinyl fluoride, polytrifluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polychlorotrifluoroethylene, and polycarbonate. Examples include monofluoride and polydicarbon monofluoride. Preferred is polytetrafluoroethylene.

The sputtering method and conditions for providing the above-mentioned underlayer, the equipment used therefor, etc. may be those known per se.

The thickness of the base layer is preferably in the range of 100 to IOOOX, particularly in the range of 200 to 600. It is thin in comparison.

In the present invention, next, a recording layer containing Te, on which information can be recorded and/or reproduced by laser light, is provided on the underlayer formed as described in section 2 above.

The recording layer preferably contains Te and Se.

Furthermore, the recording layer has Se,, Teb Me (0.02≦a≦0.35, 0.50≦b≦0.98,
The value is in the range of 0≦C≦0.45, and M is Pb,In
,Ge,S,Sb,As,Bi,Sn% ALL,
Ga, TI, Zn, Cd, Au, Pt
% Ag, Cu, Ni % Pd% Rh, C
It is preferable to have a composition represented by r% (representing at least one metal selected from Mo, W and Ta).

Furthermore, the recording layer may be made of SeaTebPbc (however,
It is preferable to have a composition represented by (a, b and C are as described above).

On the recording layer of the information recording medium of the present invention, silicon dioxide,
Tin oxide, magnesium fluoride, titanium oxide, TeOX
(However, 1≦X≦2), and it is preferable that layers made of either zirconium oxide or zinc oxide are laminated.

Among these materials, Tea, (where X is 1≦
A number in the range of X≦2, particularly preferably a number in the range of 1.5≦X≦2) is preferably laminated.

Although the recording layer containing Te has particularly excellent recording sensitivity, deterioration in sensitivity tends to occur over time after the recording layer is formed. Although the durability is improved by incorporating Se compared to Te alone, it is not sufficient. M in the above general formula
When other metals are added, for example, they have the effect of increasing light absorption, improving reflectance, and improving the flatness of the surface of the recording layer, but their contribution to the durability is can not see. Te
When a layer made of TeOX (where 1≦X≦2) or the like is laminated on a recording layer containing be able to. By making it easier to form small pits in this way, recording and reproducing characteristics such as higher resolution of recorded information and wider latitude, which indicates the applicable range of recording power to obtain a high C/N, are improved. improvement can be seen. Furthermore, in terms of durability, the C/N ratio does not decrease even after repeated reproduction, and reading durability is improved.

The thickness of the recording layer is preferably in the range of 100 to 3,000×, particularly preferably in the range of 200 to 1,200×, from the viewpoint of ease of writing information and reflectance. be.

In addition, the layer thickness of the layer consisting of Tea, etc. is 50 to 1000
The range of X is preferable, particularly preferably 100 to 500
It is within the range of X.

The recording layer is formed on the substrate by a known method such as vapor deposition, sputtering, or ion plating using the above recording layer material. A layer made of TeOX or the like is also formed on the substrate by a known method such as vapor deposition, sputtering, or ion plating in the same way as the recording layer.

Tea. A protective layer may be provided on the layer consisting of the like. The protective layer is preferably a laminate of a soft protective layer made of a soft resin material and a hard protective layer made of a hard resin material. This laminate has the soft protective layer side facing the recording layer side,
Laminated on the recording layer. Examples of the soft resin material include polyurethane, polyvinylidene chloride, ethylene/vinyl acetate copolymer, silicone rubber, styrene/butadiene rubber, polyvinylidene chloride, and polyacrylic acid ester. Typically these are solution applied,
It is applied onto the recording layer by a method such as latex coating or melt coating, and if necessary, it is subjected to treatments such as drying and heating to form a soft protective layer. The thickness of the soft protective layer is usually in the range of 100 to 5 μm, preferably in the range of 0.3 to 3 μm. Examples of hard resin materials include ultraviolet curing resins and thermosetting resins. Usually, these are applied onto a soft protective layer by a method such as solution coating, and if necessary, a treatment such as ultraviolet irradiation or heating is performed to form a hard protective layer. The thickness of the hard protective layer is usually in the range of 0.1 to 10 μm, preferably in the range of 1 to 3 μm.

The surface of the substrate opposite to the side on which the recording layer is provided is coated with, for example, silicon dioxide, tin oxide, magnesium fluoride, and the above-mentioned Tea. A thin film made of an inorganic substance such as, or a polymeric substance such as a thermoplastic resin or a photocurable resin may be provided by a method such as vacuum evaporation, sputtering, or coating.

Using the information recording medium manufactured according to the present invention, information can be recorded by an optical information recording method as described below. The information recording medium manufactured according to the present invention includes:
Since it is particularly suitable for recording CD format signals, this will be explained as an example.

First, while rotating the information recording medium at a constant linear speed of 1.2 to 1.4 m/sec, a recording light such as a semiconductor laser beam is emitted from the substrate side having pregroups on the surface of the pregroups. CD by irradiating the group with laser light.
The formatted EFM signal is recorded by forming bits in the recording layer of the group. Generally, a semiconductor laser beam having an oscillation wavelength in the range of 750 to 850 nm is used as the recording light. Generally 3-15mW
Recorded with laser power.

As a result, bits having a length of 0.70 to 4.0 μm are formed concentrically or spirally at intervals of 0.70 to 4.0 μm in the recording layer.

During recording, tracking control is performed using the tracking pre-group.

The recording of information according to the invention takes place in the bottom area of the group of the pregroup.

Information can be reproduced by rotating the recording medium at the same constant linear velocity as described above, irradiating semiconductor laser light from the substrate side, and detecting the reflected light.

Next, examples of the present invention will be described. However, these examples do not limit the invention.

[Example 1] A disc-shaped polycarbonate substrate having a tracking groove (outer diameter: 120 mm, inner diameter = 15 mm, J!; I size:
A groove with a depth of 800mm, a width at half maximum of 0.7 μm, and a pitch of 1.6 μm was provided in a spiral shape in a range of 1.2 mm, an inner diameter of 46 mm to an outer diameter of 117 mm.

This substrate was subjected to sputter etching treatment for 30 seconds at a pressure of 5 milliTorr and power of 100 W using argon as a sputter gas. The contact angle of the sputter etched surface of the substrate with water decreased from 85 degrees to 1560 degrees.

Next, polytetrafluoroethylene was used on the sputter etching surface of the substrate, sputter gas: argon, pressure 5 mm Torr, power 150 W, target distance 1.
Spatter for 15 minutes under the conditions of m1190mm to obtain a layer thickness of 45
A base layer of 0 was formed.

Next, for this base layer, a mixed target of 78 atomic %: 18 atomic % = 4 atomic % of Te, Se, and Pb was used, and a sputtering gas: argon, a pressure of 5 mmTorr, a power of 125 W, and a target distance were used. A recording layer having a thickness of 600 mm was formed by slicing for 5 minutes at a thickness of 90 mm.

On this recording layer, TeO 2 was sputtered for 3 minutes under the conditions of sputtering gas: argon, force of 5 mm Torr, power of 100 W, and target distance of 90 mm, resulting in a layer thickness of 80 mm.
T e O + of λ. r. layer was formed.

In this way, the substrate, underlayer, recording layer and T e
An information recording medium consisting of O 1+6 layers was manufactured.

1 6 Regarding the obtained information recording medium, wavelength: 780 nm, N
An EFM signal was recorded with A: 0.5, linear velocity: 1.2 m/sec, laser power: 5.6 mW, and recording waveform: duty and pulse number correction.

The recorded signal is reproduced at wavelength: 780 nm, NA: 0.
．． 45, Linear speed: 1.2m/sec, Laser power: 0.5
mW, and the C1 error (numbers/second) at that time was measured.

The results are shown in Table 1.

[Example 2] An information recording medium was manufactured in the same manner as in Example 1, except that the sputter gas for sputter etching of the substrate was changed to a mixed gas of argon + oxygen (80:20). . The condition of the sputter-etched surface of the substrate was similar to that in Example 1.

Regarding the obtained information recording medium, errors were measured in the same manner as in Example 1.

The results are shown in Table 1.

[Comparative Example 1] An information recording medium was manufactured in the same manner as in Example 1 except that the surface of the substrate was not subjected to sputter etching treatment.

Regarding the obtained information recording medium, errors were measured in the same manner as in Example 1.

The results are shown in Table 1.

[Comparative Example 2] Example 1 except that the surface of the substrate was not subjected to the sputter etching process and the sputtering time for forming the base layer was changed to 60 minutes to form a base layer with a layer thickness of 1800×. An information recording medium was manufactured in the same manner as in .

Regarding the obtained information recording medium, errors were measured in the same manner as in Example 1.

The results are shown in Table 1.

As is clear from the results in Table 1, the information recording medium manufactured according to the present invention obtained in Example 1 and Example 2 was
Compared to the information recording medium obtained in Comparative Example 1, which was manufactured without sputter etching the surface of the substrate, this information recording medium has extremely few errors and has significantly superior performance. In addition, in order to manufacture an information recording medium with the same level of error as the information recording medium manufactured according to the present invention using the conventional technology, it is necessary to make the layer thickness of the underlayer extremely large, as shown in Comparative Example 2. This results in a decrease in the productivity of the information recording medium and an increase in cost.

1 9 [Effects of the Invention] The method for manufacturing an information recording medium of the present invention has a thin base layer made of fluororesin, and does not cause deformation or peeling of the base layer from the substrate during data recording. This has the remarkable effect of making it possible to economically manufacture, with high productivity, an information recording medium that has improved sensitivity and signal quality and is particularly effective for low-speed recording and reproduction.

Claims (1)

[Claims] 1. Sputter etching is performed on the surface of the resin disk-shaped substrate on which the recording layer is to be formed, a base layer made of a fluororesin is provided by sputtering on the sputter-etched surface of the substrate, and further, a base layer made of a fluororesin is provided on the base layer. A method for manufacturing an information recording medium, comprising providing a recording layer containing Te, on which information can be recorded and/or reproduced by laser light. 2. 2. The method of manufacturing an information recording medium according to claim 1, wherein the underlayer is provided with a layer thickness of 100 to 1000 Å.