JPS6182347A - Apparatus for producing optical recording medium - Google Patents

Abstract

PURPOSE:To execute finely co-vapor deposition control by providing respectively different vapor deposition sources apart from each other at such a space at which each of monitor means is not affected by the other vapor deposition source. CONSTITUTION:The Pb vapor deposition source 11 and the PbO vapor deposition source 12 are disposed at about 180 deg. space in the peripheral direction below a substrate 10 consisting of a transparent disk-shaped material such as glass. Both vapor deposition sources 11, 12 are heated to evaporate Pb and PbO. The vapor deposition quantity of the respective vapors is measured by crystal oscillation type film thickness gages 13, 14, etc. In the stage of a vapor deposition operation, the substrate 10 is rotationally driven at 100-200rpm by a motor so that the evaporated Pb atoms and PbO molecules arrive simultaneously at the surface of the substrate 10 to form a PbOx low oxide. Since both gages 13, 14 are disposed apart from each other at 180 deg. space, the gages provide the measured values of the vapor deposition quantity of PbO and Pb respectively without picking up the mutually other Pb or PbO. The non-stoichiometric value of the PbOx low oxide (0.25<x<1) is finely controlled in accordance with the measured values.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for manufacturing an optical recording medium, particularly a write-additional (DRAW) type optical recording medium.

BACKGROUND ART As a recording layer of a DRAW type optical recording medium, there is a thin film that can be recorded and reproduced by a laser beam without changing the shape of holes or the like, and is typically made of TeOx.

Low oxides such as PbOx are known. When such a thin film is irradiated with focused intense laser light, its physical properties change and the light reflectance becomes lower or higher, thereby forming recording bits. During reproduction, a weak laser beam is irradiated to read the change in reflectance of the recorded bits.

FIG. 3 schematically shows a conventional apparatus f, f for manufacturing an optical recording medium whose recording layer is a PbOx thin film. The substrate 1 placed in the vacuum Lucha is made of transparent acrylic resin (
It is made of polymethyl methacrylate) or glass, and is rotated by a motor (not shown) at a speed of 5 to 50 rpm. A Pb evaporation source 2 and a PbO evaporation source 3 are disposed adjacent to each other below the substrate 1 . When pb and pbo from these vapor deposition sources 2 and 3 are heated and evaporated by resistance heating or electron beam heating, pb and pbo are codeposited on the surface of the substrate 1 (the back surface in FIG. 3), thereby forming a thin film of PbOx. be done. Near the vapor deposition sources 2 and 3, there is a crystal oscillation type film thickness gauge 4 for monitoring the film composition and film thickness during vapor deposition.
5 are arranged respectively. These film thickness gauges 4 and 5 change their natural frequencies f1 and f2 by picking up some of the evaporated substances pb and pbo. Their natural frequencies f1, f2
The amounts of pb and pbo deposited are measured based on the changes Δf1 and Δf2, respectively, thereby making it possible to control the deposition.

Problems to be Solved by the Invention In the conventional optical recording medium manufacturing apparatus described above, two different vapor deposition sources 3 and 4 are placed close to each other to produce evaporated substance Pb.

PBO is fused or codeposited. Pb, PbO
If they are not fused, they will be deposited in layers and P
b Ox (o, 25 (x) (1) This is because low oxides are not formed. However, since the film thickness gauges 4 and 5 are also close to other evaporation sources 3 and 2, the film thickness gauge 4 for Pb
also picks up the evaporated substance pbo from the evaporation source 3, while PbO
The film thickness gauge 5 also picks up the evaporated substance Pb from the evaporation source 2, reducing the monitoring accuracy and Pb0x(0,
Co-evaporation control to obtain an accurate non-stoichiometric value of 25(x(1)) becomes difficult.

Means for Solving the Problems The present invention provides that each monitoring means such as the film thickness meter, which is disposed near different vapor deposition sources, is spaced apart from each other so that it is not substantially influenced by other vapor deposition sources. The above problem is solved by providing these vapor deposition sources and rotating the substrate on which the thin film for optical recording is formed by co-evaporation from these different vapor deposition sources at a relatively high speed.

Although the different deposition sources are relatively widely spaced, because the substrate rotates at high speed, their evaporated materials reach the substrate surface substantially simultaneously and coalesce there, resulting in co-deposition. Each monitoring means picks up only evaporated material from a corresponding deposition source and provides an independent deposition measurement.

Embodiment One embodiment of the present invention will be described with reference to FIG. m1 and FIG.

In FIG. 1, a substrate 10 is made of acrylic resin (polymethyl methacrylate) and polycarbonate 1-(PC).

It is made of a transparent material such as glass and is shaped like a disk. Below the substrate 10, a Pb evaporation source 11 and a PbO evaporation source 12 are arranged at an interval of about 180° in the circumferential direction, as shown in FIG. These vapor deposition sources 11.1
2, pb, pb in the crucible.

Powder is placed in each chamber and heated from the outside by a tungsten wire heater or an electron beam (not shown). Near the vapor deposition sources 11 and 12, means for monitoring the film composition during vapor deposition, such as crystal oscillation type film thickness gauges 13 and 14, are respectively disposed. The film thickness gauge 13 is
A part of the Pb evaporated from the deposition source 11 is picked up, and the natural frequency changes according to the number of deposits, thereby providing a measured value of the amount of Pb deposited. The film thickness gauge 14 picks up a portion of the pbo evaporated from the evaporation source 12 and provides a measured value of the amount of PbO deposited by changing its natural frequency according to the amount of the deposited pbo. These film thickness gauges 13 and 14 are connected to the measuring device circuit (
pb, pb based on the above measured values.
The amount of vapor deposition or evaporation of o is controlled. The substrate 10 described above. Both the vapor deposition sources 11 and 12 and the film thickness gauges 13 and 14 are placed in a vacuum (lucha).

When the vapor deposition sources 11 and 12 are heated, pb and pbo are evaporated, and most of them go straight toward the front surface (back surface in FIG. 1) of the substrate 10. According to this embodiment, the substrate 10 is rotated at 100-200 rp by a motor (not shown).
The evaporated PbJg, particles, and PbO molecules reach the surface of the substrate 10 substantially simultaneously and fuse together to form a PbOx low oxide. Evaporated pb, pbo
A portion of the film thickness of 13.14I is picked up. As shown in the figure, the film thickness gage 13 is spaced approximately 180 degrees circumferentially from the evaporation source 12, so it does not pick up pbo, while the film thickness gage 14 is circumferentially spaced from the evaporation source 11. ° in direction
Since they are spaced approximately 180° apart, no Pb is picked up. Therefore, the film thickness gauge 13.14 is the same as the deposition source 11.1.
pb, pb without being affected by 2.

The non-stoichiometric value of PbOx low oxide (0,25<X<1) is precisely controlled based on these measured values.

In this example, since the substrate is rotated at a high speed of 100 to 20 Orpm, a PbOx film with a more uniform and wide area can be obtained relatively easily without forming a laminated film of Pb and pbo.

According to this example, PbOx (0,25(x (1
) was formed on the substrate 10 to a thickness of 300 to 500 μm, the required recording laser power was relatively low at 8 to 9 mW, and a C/N of 45 dB or more was obtained. Furthermore, since the recorded bits are formed by changes in physical properties and are not accompanied by changes in the shape of holes or the like, the bit edges are sharp, the noise level does not increase after recording, and there are other advantages such as low surface noise.

FIG. 3 shows another embodiment of the invention. In this embodiment, the interval between the deposition sources 11 and 12 is made relatively small, but instead, a shield 9 plate 15 is disposed between the deposition sources 11 and 12.
．． ph, pb evaporated from 12.

The film thicknesses are made to be less than 14 and 13 on the film thickness scale, respectively.

Although the above-mentioned embodiment is an apparatus for manufacturing an optical recording medium having a PbOx low oxide thin film, the present invention can also be applied to an optical recording medium having other codeposited thin films such as a MOX low oxide (M: metal) 9 alloy thin film. It is also applicable to manufacturing equipment.

Effects of the Invention According to the present invention, since the means for monitoring the film composition during vapor deposition independently monitors the vapor deposition status of the corresponding vapor deposition source without being influenced by other vapor deposition sources, more precise co-evaporation can be achieved. Can be controlled.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing one embodiment of the present invention.
FIG. 3 is a plan view of the device shown in FIG. 3, FIG. 3 is a perspective view showing another embodiment of the present invention, and FIG. 10...Substrate, 11...PB evaporation source, 12...PBO evaporation source, 13.14...
...Crystal oscillation type film thickness meter, 15...Shield plate. Patent Applicant NEC Home Electronics Co., Ltd. Patent Attorney Takashi Sasaki Figure 1 Figure 2 Figure 3 Figure 1

Claims (5)

[Claims] (1) A thin film for optical recording is formed by co-evaporating the surface of the substrate from different deposition sources while rotating the substrate, and a thin film for optical recording is formed near each of the deposition sources for monitoring the film composition during deposition. In the apparatus for manufacturing an optical recording medium, the different vapor deposition sources are arranged at intervals such that each of the monitoring means is not substantially influenced by other vapor deposition sources, and An optical recording medium manufacturing apparatus characterized by rotating at a relatively high speed. (2) The manufacturing apparatus according to claim 1, wherein the substrate is made of polymethyl methacrylate formed into a disk shape. (3) The different deposition sources each have Pb and PbO deposition materials, and the thin film is PbO_x (0.25<x<1
) The manufacturing apparatus according to claim 1, wherein the film composition is selected as follows. (4) The manufacturing apparatus according to claim 1, wherein the different evaporation sources are arranged at intervals of about 180° in the circumferential direction with respect to the substrate. (5) The manufacturing apparatus according to claim 1, wherein the substrate is rotated at 100 to 200 rpm.