TWI483247B - Manufacturing the sputtering targets for the recording layer of the recordable optical recording media - Google Patents

Description

Preparing a sputtering target for a recording layer of a recordable optical recording medium

The present invention relates to an optical recording storage medium, and more particularly to a recording layer material for a recordable information recording medium.

Optical record storage uses laser light technology to record data in an optical recording medium. In the current recordable optical discs on the market, most of the organic dyes are used as the recording layer material, and the laser is burned through a laser having a certain burning power, so that the organic dye of the recording layer is cracked or deformed, resulting in burned areas and unburned. The difference in reflectivity between recorded areas. By utilizing the difference in reflectance, the data stored in the disc can be read out by a laser of appropriate power.

Due to the narrow wavelength range of organic dye absorption light, the specific dye is only suitable for a specific wavelength range. For short-wavelength (405 nm) laser light sources used in current Blu-ray optical recording media, there are few types of organic dyes that can be applied, and the process is small. Because the substrate gauge of the Blu-ray disc is small, it is difficult to apply uniformity using organic dyes. Therefore, in recent years, it has been proposed to use an inorganic material such as metal or semi-metal to replace the organic dye as a recording layer material for a recordable optical disc.

In order to overcome the use of organic dyes only in the narrow laser light wavelength range, the specific dyes are only suitable for a specific wavelength range. The invention provides a high-stability, high light absorption rate in the visible light wavelength range, and can be changed by the laser pulse heating of various wavelengths to change the morphology or microstructure of the film interface, thereby causing the change of the reflectivity to be inorganically writable. Record the recording material of the disc.

The invention utilizes an inorganic material of a single film layer as a recording film of a recordable optical disc, mainly by irradiating a laser beam through a metal or semi-metal film, and generating an interface reaction at a recording point region to cause a microstructure change, thereby causing reflection The rate changes to achieve the purpose of digital signal recording.

The invention provides a writable optical recording medium, which can read and write data by using laser light incident on the opposite side of the substrate (11). If the film structure is adjusted, the laser light incident on the substrate side can also be used for reading and writing data. . The film structure of the film layer coated on the substrate (11) is as shown in the first figure is a structure of a writable optical recording medium comprising a reflective layer (12), a first buffer layer (13), and a recording layer ( 14), a second buffer layer (15), a light compensation layer (16) and a light penetrating layer (17). The structure is a reflective layer (12) on a substrate (11), a substrate (11), a first buffer layer (13) on the reflective layer (12), and a first buffer layer (13). a recording layer (14), a second buffer layer (15) on the recording layer (14), a light compensation layer (16) on the second buffer layer (15), and a light transmissive layer (17) on the uppermost layer, The optical recording medium of this structure can be projected by the light penetrating layer (17) side of the thunder The beam (18) is illuminated to read and write data. As shown in the first figure, the recording layer (14) of the single film layer absorbs the laser light and generates a local microstructure change after being irradiated by the laser beam (18), and the interface elements are mutually diffused to form a mixed region. . Because of the different film structure, the mixed area caused by the heating of the laser light and the unmixed area not heated by the laser light have obvious reflectance difference, so the difference in reflectance can be used to achieve the purpose of recording data.

The invention discloses a writable optical recording medium using a recording layer (14) structure of a single film layer, which can be used for the purpose of recording data. In the embodiment, the writable optical recording medium of the present invention can perform high-speed and stable writing of data by using laser light of a wavelength in the visible light range, and can store data for a long time, but this embodiment is only the best for describing the present invention. The method of implementation is not intended to limit the scope of the invention.

The writable optical recording medium structure of the present embodiment is as shown in the first figure, and comprises a substrate (11), a reflective layer (12), a first buffer layer (13), a recording layer (14), and a second buffer layer ( 15), a light compensation layer (16) and a light penetrating layer (17). The structure is a reflective layer (12) on a substrate (11), a substrate (11), a first buffer layer (13) on the reflective layer (12), and a first buffer layer (13). a recording layer (14), a second buffer layer (15) on the recording layer (14), a light compensation layer (16) on the second buffer layer (15), and a light transmissive layer (17) on the uppermost layer, The optical recording medium of this structure can be irradiated by a laser beam (18) projected on the side of the light transmissive layer (17) for reading and writing data.

In the structure of the embodiment, the substrate (11) is provided with an optically transparent material, and can provide appropriate mechanical strength of the recording medium, and the material includes a polycarbonate resin, a polymethyl methacrylate, and a polymethyl methacrylate. Polystyrene resin, polyethylene resin, polypropylene resin, etc., the substrate (11) is pre-engraved with grooves and land, when the data is recorded or When reading, these grooves and land can be used as laser beam guides and data recording positions.

In the structure of this embodiment, the material of the reflective layer (12) is selected from the group consisting of gold (Au), silver (Ag), molybdenum (Mo), aluminum (Al), titanium (Ti), tantalum (Ta), and niobium (Nd). The element of bismuth (Bi) and the alloy of the above-mentioned element as a main component have a thickness of between 5 nm and 300 nm. In the structure of the embodiment, the materials of the first buffer layer (13) and the second buffer layer (15) are selected from the group consisting of zinc sulfide-yttria (ZnS-SiO ₂ ), tantalum nitride (SiN), and tantalum nitride (GeN). A dielectric material such as tantalum carbide (SiC), each having a thickness of between 1 nm and 300 nm. It may be composed of a single layer or more of the above materials. In the structure of this embodiment, the material of the recording layer (14) is selected from the group consisting of copper (Cu), bismuth (Si) and chromium (Cr), and the single target is made to have a thickness of between 3 nm and 50 nm.

In the structure of this embodiment, the material of the light compensation layer (16) is selected from the group consisting of bismuth oxynitride (SiON) and having a thickness of between 3 nm and 50 nm. In the structure of the embodiment, the light penetrating layer (17) is a photohardening resin for protecting the film layer stability of the optical recording medium, and avoiding the film material being subjected to abrasion, moisture deterioration or exposure to oxidation in the air.

An embodiment of the present invention is as follows: A blue-ray disc substrate (11) having a groove and a land at a moment, having a gauge of 74 μm and a thickness of 1.1 mm, is prepared. A 20 nm thick silver (Ag) reflective layer (12) is deposited on the substrate (11) by magnetron sputtering; then a 20 nm thick zinc sulfide-yttria (ZnS-) is deposited on the reflective layer (12). SiO ₂ ) a first buffer layer (13); then a 14 nm thick recording layer (14) copper (Cu), bismuth (Si) and chromium (Cr) mixed layer is formed on the first buffer layer (13); A 20 nm thick zinc sulfide-yttria (ZnS-SiO ₂ ) second buffer layer (15) is plated on the recording layer (14); and then a 15 nm light compensation layer is formed after the second buffer layer (15). Niobium oxynitride (SiON); Finally, a light-transmissive film with a thickness of 0.1 mm is attached to the light-compensating layer (16) as a light-transmitting layer, and the disc of the experimental example is completed The figure shows.

The thickness of the sputtered film was observed with an atomic force microscope (AFM) and E-ta Optik; the dynamic analysis of the disc was performed using a Pulstec ODU-1000 dynamic tester to measure the dynamic properties of the disc. The measured write power is between 3mW and 14mW, the laser wavelength is λ=405nm, the numerical aperture mirror is NA=0.85, and the write line speeds are 4.92m/s, 9.84m/s, 19.68m/s and 29.52m respectively. /s, conforms to the specifications of Blu-ray recordable disc 1x speed, 2x speed, 4x speed and 6x speed recording speed.

As shown in the second figure, the dynamic test results of the disc write power and the modulation of the disc produced for this embodiment can be seen from the results of the second graph, the Blu-ray recordable disc is at 1x speed. , 2x speed, 4x speed and 6x speed recording speed, modulation value with write power The increase is increased, and at different write speeds and write powers, the modulation value can be more than 0.6, which is in line with the specifications of the Blu-ray recordable optical disc (the specification requires 0.4 or more).

When the recording speed of the Blu-ray recordable disc is 1x, the write power needs to be greater than 3.1mW to measure the jitter value. The jitter value decreases as the write power increases. When the write power is 5.0mW, A lower jitter value of about 5.1% is obtained. As the write power continues to increase, the jitter value also increases as the write power increases. If the test is performed at a write speed of 2x speed, the same trend occurs. The write power needs to be greater than 3.45mW to measure the jitter value. The jitter value decreases as the write power increases. When the write power is At 5.55mW, a lower jitter value of about 5.4% is obtained, and as the write power continues to increase, the jitter value also increases as the write power increases. If you use the 4x speed write speed for testing, the same trend occurs. The write power needs to be greater than 5.7mW to measure the jitter value. The jitter value decreases as the write power increases. When the write power is At 8.9mW, a lower jitter value of about 6.1% is obtained. As the write power continues to increase, the jitter value also increases as the write power increases. If you use the 6x speed write speed for testing, the same trend occurs. The write power needs to be greater than 7.8mW to measure the jitter value. The jitter value decreases as the write power increases. When the write power is At 11.2mW, a lower jitter value of about 6.5% is obtained, and as the write power continues to increase, the jitter value also increases as the write power increases. When the laser writes the signal, the recording layer is heated by the laser light pulse and the temperature rises. When the writing power is too small, the temperature of the recording layer is too low, and the reflectance of the film cannot be changed, so the jitter value cannot be measured. With modulation values; When the write power is too large, the jitter value rises as the write power increases. This may be because the laser power is too high, causing the recording layer temperature to be too high, causing distortion of the disc film structure and causing jitter. The jitter rises, so the write power of a general optical disc has an appropriate range. In this experimental example, the recording speed of the Blu-ray recordable optical disc is written at 1x speed to 4x speed, the write power is 3~11.5mW, and the data is written with the appropriate write power, and the jitter value (jitter) ) can be maintained below 6.5%, and even when the recording speed is as high as 6 times, the jitter value can reach 6.5% or less, which meets the recording requirements of the recordable Blu-ray disc, and proves that the optical recording medium has practicality.

11‧‧‧Substrate

12‧‧‧reflective layer

13‧‧‧First buffer layer

14‧‧‧recording layer

15‧‧‧Second buffer layer

16‧‧‧Light compensation layer

17‧‧‧Light penetrating layer

18‧‧‧Laser beam

The first figure shows the structure of a writable optical recording medium.

The second figure is a dynamic test result of the test writeable recording medium recording power and modulation of the embodiment.

The third figure is a dynamic test result of the test writeable optical recording medium write power and jitter value of the embodiment.

11‧‧‧Substrate

12‧‧‧reflective layer

13‧‧‧First buffer layer

14‧‧‧recording layer

15‧‧‧Second buffer layer

16‧‧‧Light compensation layer

17‧‧‧Light penetrating layer

18‧‧‧Laser beam

Claims (6)

A sputtering target for preparing a recording layer of a writable optical recording medium, comprising copper (Cu), bismuth (Si), and chromium (Cr), and the target is crystalline. The sputtering target for preparing a recording layer of a writable optical recording medium according to claim 1 of the patent application can be made by pressing each of copper (Cu), bismuth (Si) and chromium (Cr) elements. Single target. The sputtering target for preparing a recording layer of a recordable optical recording medium according to claim 1 of the patent application may be a single copper (Cu) and bismuth (Si) alloy and a chromium (Cr) element. Target. The sputtering target for preparing a recording layer of a recordable optical recording medium according to claim 1 of the patent application may be a single copper (Cu) element and a bismuth (Si) and chromium (Cr) alloy. Target. The sputtering target for preparing a recording layer of a recordable optical recording medium according to claim 1 of the patent application may be a single unit of bismuth (Si) element and copper (Cu) and chromium (Cr) alloy, respectively. Target. A sputtering target for preparing a recording layer of a recordable optical recording medium according to claim 1, wherein the thickness of the recording layer is preferably from 3 nm to 50 nm ( Between nm).