JPS5935356B2 - Information recording member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a member for recording information, in which a thin film provided on a predetermined substrate is irradiated with an energy beam such as a laser beam to form a depression in the irradiated area, thereby recording information. The purpose of the present invention is to provide a member suitable for recording.

Conventionally, inorganic materials have been used as materials for forming thin films for recording by irradiating energy beams such as laser beams (or electron beams in some cases) on thin films to form depressions in the irradiated areas. is Bi, Bi-Be, C
d, Ge15Te85-x(PbI2)x, etc. are known.

These are certainly useful materials for specific applications, but according to the inventor's experiments, the shape (particularly the outline) of the recess is disordered in the case of Bl and Bl-Be (7), and in the case of Cd. Due to the disadvantage that it is difficult to deposit a flat film, it is not suitable for applications where the flatness of the deposited film and the shape of the recesses have a large effect on the signal-to-noise ratio, such as for video discs. It has become clear that there are practical problems. The present invention aims to provide a recording member that is superior to these conventional recording materials.

The present invention is a recording member containing Te and Be. The advantage of the material according to the present invention is that firstly, in the process of writing this information using a processing beam, the thin film that is to become a recording member tends to be spherical, and the shape of the outer periphery of the formed recess is easy to form. This is to prevent the signal from being disturbed and reducing the signal-to-noise ratio of the signal. The second purpose is to make the deposited film more likely to become amorphous and to prevent noise from occurring due to unevenness on the film surface due to crystal grains. The purpose of FIG. 3 is to prevent surface oxidation of the deposited film. As a result of considering the above-mentioned points, it was found that the content of Se is generally 5% or more, preferably 15% or more in terms of atomic percentage.

Note that the more detailed composition range varies depending on the intended use of this recording member.

For example, when reading is performed using directly reflected light or transmitted light, the Se content is preferably 70% or less, more preferably 50% or less, in order not to reduce the contrast. Further, when used as a mask for contact exposure of photoresist, the content of Se is preferably 20% or less so that it can be dissolved with nitric acid. Se and T
Contained elements other than e include Sb, Bi, Zn, Cd, A
t, Ga, ln, Si, Ge, Sn, Sb, Ta, CU
, AU, Ag, Tt, P, j6, and S, the shape of the recessed portion to be formed may be adjusted and good results may be obtained.

However, the total content of elements other than Te and Se must be 30% or less in terms of atomic percentage.
This is preferable in order not to lose the characteristics of the recording member of the present invention. Moreover, it goes without saying that even if it is an element other than these, a small amount of an element that does not significantly change the properties of the material may be added.

Note that the thickness of the recording member is preferably about 200 to 1000λ.

The reason for this is as follows. Table 1 shows Te8Ose2
The graph shows the amount of decrease in the S/N ratio from the initial value when an O recording film is maintained at 40° C. and 5% humidity for three months. As shown in Table 1, even if the film contains % Se2O, if the film thickness is too thin (less than 200λ), the effect of oxidation is large.

Conversely, if the film thickness is made too thick, there will be no level difference between the 16 MHz harmonic (due to distortion of the hole shape) and the 8 MHz signal when an 8 MHz carrier is initially recorded.
This is shown in Table 2. Therefore, a stirred effect is exhibited when the film thickness is in the range of 200 to 1000λ.

Since the information recording member of the present invention has the property of being able to form fine patterns, it is possible to use the information written in the information recording member to read information directly from the member. In addition, there is a method of copying and using the information written in the form of unevenness on the information recording member by forming a replica of the unevenness, and a use of the above-mentioned recording member on which information is recorded. There is a method in which a recess is formed in, for example, a photoresist layer provided adjacent to the above-mentioned member by using the recess as a mask for etching or exposure, and a replica is formed from this to obtain a large step difference in the recess.

In addition, it can be used to form a photoresist exposure mask for ICs, an electrical insulating layer with a fine pattern such as an interlayer insulating layer of multilayer wiring, and a mask for etching, diffusion, or ion implantation. is also possible. The present invention will be explained in detail below using Examples. Example 1 As shown in Fig. 1, a 35Cr diameter piece with both sides optically polished and cleaned! An L glass disk 1 is arranged in a vacuum evaporation apparatus so as to be rotatable around a central axis 2,
Four evaporation boats 3, 4, 5, and 6 are placed below the portion of the disk where information is to be recorded and approximately located on a circle having the same center as the central axis.

Between each boat and the glass disk are fan-shaped slits 7, 8, 9, and 10 and shutters 11, 12.
, 13, and 14 so that when the shutter moves, a desired proportion of the slits are covered. Only two of the four deposition boats are used, and Se and Te are added to them, respectively. After evacuating the device, the glass disk was heated to 120 rpm.
pm and a current is passed through each boat to evaporate the material in each boat. The amount of evaporation from each boat is measured by crystal film thickness monitors 15, 16, 17, and 18.
The current flowing through the boat is controlled so that the evaporation rate remains constant. The ratio of deposition rates from each boat to the disk is determined by the ratio of the opening angles of each shutter. The thickness of the deposited film was approximately 400λ. The composition of the deposited film is typically Se9OTelO, se7OTe3O9se.
5OTe5O9se3OTe7O9selOTe9O was deposited. In order to record on the film formed as described above, as shown in FIG. The argon laser beam (4880λ) 20 of approximately 15 mW is focused by a lens and irradiated with pulsed argon laser light (4880λ) whose pulse interval is modulated according to the information to be recorded.

The deposited film on the part irradiated with the laser beam has a major axis of approximately 1.2 μM. An elliptical hole with a minor axis of 0.7 μm is made, and recording is performed. The smooth outline of this hole means that
This is a condition for low noise and accurate reading. The lens holder is moved on a line parallel to the radial direction of the disk in accordance with the rotation of the disk. Recording is read out as follows.

That is, the disk is rotated at 1800 rpm and the read head is brought close to the disk at a constant distance. H
The e-Ne laser beam is focused by a lens and irradiated, and changes in the intensity and phase of the reflected light are detected by a detector. The signal-to-noise ratio for each deposited film composition was measured as follows. That is, the disk was rotated at 1800 rpm, and a 6 MHz pulse-like signal with a pulse width of 65 ns was previously recorded with a 15 mW argon laser beam, and read out using the density of the reflected light using a He-Ne laser (6328λ). As a result, the initial signal-to-noise ratio for each composition was as follows. Se9OTelO:
~30dB1Se70Te30: ~35dBsSe50
Te50: ~40dB, Se30Te70: ~30d&
SelOTe9O: 30 dBS Elements other than Se and Te that exhibit effects when added are as follows.

Addition of Cd or Zn does not reduce the reflectance, and in a deposited film containing a large amount of Te, T
♂≦This has the effect of improving the tendency to form beads due to surface tension during recording, which tends to generate noise. Addition of At, Ga, or In has the effect of preventing bulges from forming around the recesses formed by recording. Addition of S or P also has the effect of preventing bulges from forming around the recesses. The addition of e has the effect of reducing the toxicity of the deposited film without disturbing the shape of the recess. For example, Se2OTe7OGe
The signal-to-noise ratio is about 35 dB for the composition of 1O, and the one with the composition of Se
The signal-to-noise ratio of the composition of lOTe5OGe4O was about 30 dB. In addition to the above, Sb, Bi, Si,
Sn, Pb, Ta, Cu, Ag, I and Tt are also suitably added, for example in the form of Sb3, BiI2, Pb2, which bring about a slight improvement in the signal-to-noise ratio if the amount of addition is selected appropriately. Addition of At is also effective in stabilizing the deposited film and preventing it from changing over time.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of an apparatus for vapor-depositing a recording member in an embodiment of the present invention, and FIG. 2 is a diagram showing the structure of an apparatus for vapor-depositing a recording member in an embodiment of the invention. FIG. 3 is a diagram showing the structure of a recording device.

Claims (1)

[Scope of Claims] 1. An information recording member that records information by forming a thin film on a predetermined substrate and irradiating the thin film with a processing beam to form a recess in the thin film, Information characterized in that the thin film is made of Se and Te, the content of Se is in the range of 5% to 50% in terms of atomic percent, and the thickness of the thin film is in the range of 200 Å to 1000 Å. A recording member. 2. An information recording member in which information is recorded by forming a thin film on a predetermined substrate and irradiating the thin film with a processing beam to form a recess in the thin film, wherein the thin film is made of Se and Te. and Cd, Zn, Al, Ga, I
n, S, P, Ge, Sb, Bi, Si, Sn, Pb, T
The content of Se is in the range of 5% to 50% by number of atoms, and the content of Se other than Se and Te is at least one element selected from the group consisting of An information recording member characterized in that the total amount of elements is 30% or less in terms of atomic percentage, and the thickness of the thin film is in the range of 200 Å to 1000 Å.