JPS59119550A - Information recording member - Google Patents

Abstract

PURPOSE:To enable satisfactory forming of continuous spiral projecting or recessed parts on an original plate by forming successively the 1st layer having energy absorptivity and gas liberation property, the 2nd layer consisting of a metal having a large coefft. of thermal expansion and the 3rd layer consisting of a metal having a small coefft. of thermal expansion and excellent stretchability on a base plate thereby forming an information recording member to be formed with the projecting parts by irradiation of a laser beam. CONSTITUTION:The 1st layer 12 to be formed on a glass base plate 11 contains adequately a low-melting metal, such as Te, Bi or the like and <=600 deg.C melting point and C, N, H and O, and is formed by sputtering a target of the above- mentioned metal by plasma. The 2nd layer 13 is adequately a thin film contg. Zn, Sb, Cd, Tl, Mg, Al, Mn, Ag, and is formed by sputtering the target of these materials in vacuum or by plasma or by vacuum deposition. The 3rd layer 14 is a thin film contg. Au, Pd, Pt, Ti, Cr, Ta, Mo and Zr and is also formed by the method similar for the 2nd layer.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an information recording member in which convex portions are formed by irradiation with an energy beam such as a laser beam, and more specifically, to a master disc or information recording member for producing an information recording medium. The present invention relates to an information recording member used as a recording medium itself.

[Technical background of the invention and its problems]

In a writable optical information recording medium, that is, a disk-shaped recording medium called an optical disk in which information signals are recorded and reproduced by irradiation with a laser beam,
For stable tracking during recording and playback and the need to increase recording density (track density), the media substrate (
Disk substrates are often used in which continuous spiral convex portions or concave portions that are optically distinguishable on the recording layer are formed on the recording layer. Conventionally, a disk substrate on which continuous spiral-shaped protrusions or recesses are formed is produced by forming the protrusions or recesses by a method such as electroforming from a master disk on which continuous spiral-shaped protrusions or four parts are formed. A stamper with the transfer is made and injection molded using this Stanono arm.

It is manufactured by transferring the convex portion or four portions onto a disk substrate using methods such as compression molding or casting.

On the other hand, a master disc having concave or convex portions is generally manufactured by the following method. That is, a Cr film is deposited on a flat substrate such as glass, and a photoresist is applied thereon using a spinner. Next, while rotating this substrate, 1 μmφ
Exposure is performed in a continuous spiral by irradiating a laser beam that has been focused to a certain degree onto the photoresist while moving it in the radial direction of the substrate at a predetermined feed speed.

Then, further development and baking are performed to obtain a master disc.

However, with this master disk manufacturing method, it is difficult to form uniformly shaped convex portions or concave portions over the entire surface of the substrate. The shape of the convex portion or concave portion to be formed on the substrate is, for example, a convex portion having a height of about 1000X, which has a wavelength of about 5OOOL of a semiconductor radar, which is usually used, in order to enable stable tracking. The width is required to be approximately 1 μm. Also, the size of the board is 30 cr from the point of view of recording capacity.
A diameter of about nφ or more is required. However, the spinner coating method is a technique that is normally used for coating films with a thickness of 1 to 2 μm or more, and it is extremely difficult to form a uniform coating film of 1000 squares on the entire surface of a large area substrate such as 30 mφ using this method. It is difficult and partial peeling is inevitable. Furthermore, even a slight amount of dust in the atmosphere that adheres to the substrate surface can cause serious coating unevenness. Furthermore, it is extremely difficult to uniformly develop such a thin photoresist over the entire area. Therefore, it is almost impossible to produce a master disk in which continuous spiral convex portions or four portions for tracking are well formed using a photoresist method using spinner coating.

[Purpose of the invention]

The purpose of the present invention is to provide an information recording member suitable as a master disc material for producing a master disc with a uniform force over the entire surface and a well-controlled continuous serpentine convex force; It is about providing.

[Summary of the invention]

The information recording member according to the present invention forms a convex portion by irradiation with an energy beam such as a laser beam, and includes a first layer having an energy absorbing property and a gas releasing property on a substrate, and a thermal expansion coefficient. It is characterized by sequentially forming a second layer made of a metal with a large coefficient of thermal expansion and a third layer made of a metal with a low coefficient of thermal expansion and high extensibility.

In this information recording member of the 1st I'I structure, when an energy beam, for example a laser beam, is emitted from the irradiation part, the laser beam is partially reflected, and the remaining energy is transferred to the third layer, the second layer and the first layer. absorbed in the layers and locally heats these layers. 1st
The layer has energy absorbing properties as well as gas liberating properties, and releases gas when irradiated with a laser beam. The pressure of this released gas acts to push up the second and third layers, forming a convex portion in the laser beam irradiation area.

Here, since the second layer has a large coefficient of thermal expansion, the third layer is
A large convex deformation is formed in the layer. Since the third layer has a low coefficient of thermal expansion and is highly resistant to spreading, the formed convex portions are permanent.

〔Effect of the invention〕

According to this invention, unlike a photoresist applied by a spinner, all of the first layer, second layer, and third layer are coated with A? It can be formed using normal thin film forming methods such as filtration, evaporation, etc. Because it is flexible, it can be formed uniformly in a clean state without any impurities such as dust in the atmosphere, and without the occurrence of peeling parts. d! can.

Furthermore, since the convex part is formed using the pressure of the gas released from the first layer by heating with a laser beam etc. and the difference in the characteristics of the second and third layers, the beam shape (height) 9 width) can be easily obtained.

In other words, when a highly extensible metal film is directly formed on the first layer, the height of the convex portion depends almost only on the magnitude of the gas pressure because such a metal film generally has a small coefficient of thermal expansion. If there is a second layer made of a metal with a large coefficient of thermal expansion below this, deformation with a large height of the convex portion can be obtained. In addition, the third layer made of highly extensible metal is not formed, and the second layer is formed on the first layer.
If only a layer is formed, the height of the convex portion will temporarily undergo large deformation during irradiation with a laser beam, etc., but it will shrink when the irradiation with a laser beam, etc. is stopped. If provided, a large deformation in the height of the convex portion will be permanently formed due to its extensibility.

Therefore, according to the present invention, it is possible to form a convex portion having a uniform and good shape over the entire surface of the substrate.

[Embodiments of the invention]

FIG. 1 is a sectional view of an information recording member according to the present invention. A first layer 12 having energy absorbing properties and gas releasing properties is formed on the glass substrate 11, and a third layer 1 made of a metal with a low coefficient of thermal expansion and high extensibility is further formed thereon.
4 is formed (2. The first layer 12 is To,
Suitable materials include a so-called low melting point metal with a melting point of 600° C. or lower, such as Bl, and at least one of C, N, H, and 0.
In vacuum, add CHr NH5, CO2.

It can be formed by sputtering with a plasma of gas such as H2. For example, a thickness of 1000X formed by sputtering To tart with CH4 gas plasma
A thin film with a component ratio of "50C50H2G" has a wavelength of 830
Absorbs 40 degrees of 0X light energy and heats up to 150℃ in air
When heated above this level, gas is released accompanied by a weight loss of 30q6.

The second layer 13 is made of Zn, Sb*Cd, Ttr
If a thin film containing at least one of MgrAt + Mn + Ag is suitable, a target of these metals can be formed by Ar gas plasma in vacuum, Talinx, or vacuum evaporation.

The third layer 14 is Au l Pd l Pt l Ti l
A thin film containing at least one of Cr + Ta 1Mo and Zr is suitable, and like the second layer, this can also be formed by a normal thin film forming method such as sputtering or vacuum evaporation.

Next, an embodiment of the master production process using the information recording member having the structure shown in FIG. 1 will be described. First, a first A! As No. 12, a Te50C30H20 film having a thickness of 4000× was formed. Next, the second layer 13 is made of Zn, which has a large coefficient of thermal expansion of 40 x 10 deg.
A film was formed to a thickness of 200X, and then, as the third layer 14, an Au film having a small coefficient of thermal expansion of 14 x 10 deg but excellent stretchability was formed to a thickness of 200X. Te5oC
The 3oH2o film was formed by sputtering Te terdat with CH4 gas plasma, and the Zn film and Au film were formed by
n, Au tag, and T were formed by sputtering with Ar gas plasma. In this case, after forming the first layer 12,
Second layer13. It is desirable to form the third layer 14 immediately and continuously in the same vacuum container in order to avoid being affected by dust in the atmosphere.

Next, as shown in Figure 2(,), three types of layers 12° x 3,
The substrate 11 on which 14 has been formed is taken out of the vacuum container, placed and fixed on the rotating support 2, and rotated at a linear speed of 6 m/see, and the semiconductor laser beam 23 focused to 1 μmφ by the lens 22 is focused to a predetermined beam. While moving radially at speed, the third
The layer 14 was irradiated. However, the laser beam 23 was a continuously modulated beam with a power of 10 mW.

By irradiating this laser beam 23, as shown in FIG. 2(b), on the surface of the third layer 14 in the laser beam irradiated area,
It was observed using a scanning electron microscope that a continuous spiral convex portion 24 with a uniform height of 0.14 m and a width of 1.1 μm at the bottom was formed. 50030H20 film with only a 200-layer Zn film formed as a second layer, and 2001
When we fabricated a film with only an oAu film and exposed it to a laser beam in the same manner as above, we found that no matter how we changed the linear velocity, laser beam power, etc. Therefore, it is not possible to make it more than 0.05 μm,
In the latter case, it was not possible to increase the thickness to 0.03 μm or more.

As another example, a Te5oC3oN5H45 film with a thickness of 3500X is deposited on a glass substrate 11 with a diameter of 30 in the first IQ.
12, and a Cd film (
Thermal expansion coefficient 30 x 10-0-6 de'), and the third
The layer 14 is a TI film (thermal expansion coefficient 9 x 10-' de
g-') was formed. When laser beam exposure was performed in the same manner as in the previous example, a convex portion having a continuous square shape with a height of 0.09 μm and a width of 1.1 μm at the bottom was formed.

In addition, as the second layer 13 for others, sb (thermal expansion coefficient 37
X10'dsg-'), Tt (28 X 10-'
'dog-'), Mg (26 x 10")
deg-'), At(24 x 10-'deg-
' ), Mn (22 x 10-'dsg-'
), Ag (20x10 deg), etc. can be used. Further, the third layer 14 is made of Pd (coefficient of thermal expansion 12 x 1
0-0-6do'), pt (do'9 x 10-0-6
de' ), TI (9 X 10-'d@g-'
), Ta (7 x 10 = deg-'), Cr
(same 6 X'1010-6de'), Mo (same 5
10=deg-'), Zr(deg-'), Zr(deg-')
6de'), etc. can be used. Second layer13. 3rd layer 1
It was confirmed that in any combination of these metal films, a convex portion having a height of 0.07 μm or more and a good shape was formed.

Next, a process for manufacturing an information recording medium having a convex portion or four portions in a continuous strip or spiral shape using the master disc shown in FIG. 2(b) will be described. As shown in Fig. 2(b), continuous i'? On the third layer 14 on which the circular convex portion 24 is formed, a third
As shown in the figure (,), first, a peeling layer 31 with a film thickness of 100X is used.
A pre-tetrafluoroethylene film of about 300× is formed on top of it, and an Au film of about 300× is formed as an electrode 32 for electroforming.
After forming the film, a metal plate 33 such as electroforming method Nyoj5 N1 etc.
was formed. The thickness of the metal plate 33 is approximately 30011 m. Thereafter, the electrode 32 and the release layer 31 are separated by an electrolytic cleaning method using the metal plate 33 as an electrode.
A stamper, as shown in FIG. 3(b), is made of an electrode 32 and a metal plate 33, which has a concave portion 34 in which the shape of the convex portion 24 formed on the first 3M14 is reversed and transferred. . At this time, the electrode 32 is attached to the metal plate 3 extremely firmly.
No trace of the film material of the release layer 31 was observed on the surface of the film. Further, the height of the recessed portion 34 on the surface of this stamper was 0.1 μm and the width was 1 μm.

Next, using this stand i4, a disk substrate 35 made of acrylic as shown in FIG. 3(C) is manufactured by injection molding.
was produced. On this substrate 35, a continuous square/4' spiral convex portion 36 having a height of 0.09 μm was formed uniformly over the entire surface. By forming a recording layer 37 on this disk substrate 35, an optical information recording medium is obtained.

In the above embodiment, an information recording medium was produced from the master disc shown in FIG. 2(b) through a stunt glosser, but it is also possible to use the master disc as it is as a stunning disc. An example thereof will be described below.

That is, first, an acrylic ultraviolet curable resin is applied onto the master disc shown in FIG.
The ultraviolet curing resin layer was cured by irradiating ultraviolet rays with an intensity of 0 W/crn for 27 tIec. Next, when the acrylic substrate was peeled off from the master, the ultraviolet curing resin layer was extremely firmly attached to the acrylic substrate, and no trace of the Au film of the third layer 14 was observed on its surface. The thickness of the ultraviolet curable resin layer on the acrylic substrate is 100 μm, and the information recording member according to the present invention can be used not only as a master disc but also as an optical information recording medium itself.

An example of this will be described below. A 12αφ polycarbonate substrate is used as the substrate 1 in FIG. 1, and a 3000X thick Te5[IClH2O
An At film with a thickness of 100X was formed as the second layer 13, and a Cr film with a thickness of 200X was formed as the third layer 14 to obtain an optical information recording medium. Laser beam exposure was performed on this medium in the same manner as in the master production process shown in FIG. However, the rotational speed of the medium was constant at 1800 rpm, the laser beam exposure length was 8200X, and the power was 15 mW at the film surface. Further, the laser beam was pulse-modulated according to the information signal to be recorded. As a result of this laser beam exposure, discontinuous spiral convex portions (pit rows) were formed on the medium surface, the length of which varied according to the information signal. The height of the convex portion was 0.2 μm, and the width of the bottom portion was 1 μm.

When the medium on which information was recorded in the form of a pit string was rotated at 1800 rpm, the same speed as during recording, and the presence or absence of convexities was detected using a 1 mW continuous laser beam, the S/N of the reproduced signal was A relatively good value of 38 dB was obtained.

This invention can be implemented with various other modifications.For example, instead of forming a continuous spiral convex portion on the master disc, a pit array corresponding to the information signal can be formed by performing eclipse on a laser beam pulse-modulated by an information signal. A disc substrate is formed by injection molding using this master disc or a stamper manufactured from this, and a reflective film such as an At film is formed on it, thereby obtaining an optical information recording medium exclusively for reproduction. You can also do it.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an information recording member according to an embodiment of the present invention, FIG. figure(,)
(b) (c) is a diagram showing the process of manufacturing an information recording medium from the master disc in Figure 2 (b) via a stamper, and Figure 4 shows information produced using the master disc in Figure 1 (b) as a stamper. FIG. 2 is a cross-sectional view of a recording medium. 1.. Substrate, 12.. 1st layer, 13.. 2nd layer, 14.. 3rd layer, 2.. Rotating support base, 22..
・Lens, 23... Laser beam, 24... Convex part,
31... Peeling layer, 32... Electroforming electrode, 33...
Metal plate, 34... recess, 36... disk substrate, 3
6... Convex portion, 37... Recording layer, 41... Disc substrate, 42... Concave portion, 43... Recording layer. Figure 1A Figure 2Figure 3(b) Figure 4

Claims (4)

[Claims] (1) In an information recording member in which a convex portion is formed by irradiation with an energy beam, a first layer having energy absorbing properties and gas releasing properties on a substrate, a second layer made of a metal with a high coefficient of thermal expansion, and a second layer made of a metal with a high coefficient of thermal expansion and a thermally expandable layer. An information recording member characterized in that a third layer made of a metal having a low elasticity and high extensibility is successively formed. (2) The first layer is made of metal with a melting point of 600°C or less, CN, H
, O. , O. , O. (3) lj2 layer is Zn, Sb + Cd, Tt
The information recording member according to claim 1, characterized in that it contains one or more of the following: r Mg r At +Mn and Ag. (4) mZ 3 layer is Au*PdrPt,
Ti, Cr + Ta. The information recording member according to claim 1, characterized in that it contains one or more of Mo + Zr.