TW200417620A - Silver alloy sputtering target for forming a reflective layer of an optical recording media - Google Patents

Abstract

To provide a silver alloy sputtering target for forming an Ag alloy reflective layer of an optical recording media, such as a magneto-optical recording disc (MD, MO) and an optical recording disc (CD-RW, DVD-RAM). It comprises a silver alloy having a composition of (1) 0.5-3 mass% of Cu, a total of 0.1-3 mass% of one or more selected from Dy, La, Nd, Tb, and Gd, and the remainder of Ag; (2) 0.5-3 mass% of Cu, a total of 0.005-0.05 mass% of one or more selected from Ca, Be, and Si, and the remainder of Ag; or (3) 0.5-3 mass% of Cu, a total of 0.1-3 mass% of one or more selected from Dy, La, Nd, Tb, and Gd, a total of 0.005-0.05 mass% of one or more selected from Ca, Be, and Si, and the remainder of Ag.

Description

200417620 (1) 发明 Description of the invention [Technical field to which the invention belongs] The present invention is used in the sputtering method to form information signals such as playing sound, video, and text using laser beams such as semiconductor lasers or to perform writing and reading. Inside the erased optical recording disc (CD-RW, DVD-RW), a silver alloy sputtering target called a translucent reflective layer or a reflective layer (hereinafter collectively referred to as a reflective layer) of a structural layer. [Prior art] The reflective layer of optical recording media such as magneto-optical recording discs (MD, MO), optical recording discs (〇1) _RW, DVD-RW) has traditionally used a reflective layer of silver or a silver alloy. These silver or silver alloy reflective layers have extremely high reflectance in a wide wavelength range of 4,000 to 830 nm, especially the short-wavelength laser light used in high-density writing of optical recording media has good reflection Rate, so it is very suitable for the above fields. The foregoing silver or silver alloy reflective layer can be obtained by sputtering a silver or silver alloy sputtering target (refer to Japanese Patent Application Laid-Open No. 1 1-2 1 344 8, Japanese Patent Application Laid-Open No. 2000 ·· Publication No. 109943, Japanese Patent Laid-Open No. 2000-57627, etc.). However, even if a phase change recording material is used in an optical recording medium that repeatedly performs writing, reading, and erasing, as the number of writing, reading, and erasing increases, the silver or silver alloy is reflected. The reflectivity of the layer decreases, so it does not have the characteristics of long-term reading and writing. -5- (2) (2) 200417620 [Summary of the Invention] One of the reasons why xa has the above result is that when the optical recording medium performs writing, reading, and erasing, the silver reflective layer is continuously caused by the irradiation of laser light. Heating and cooling cause recrystallization of the silver reflective layer, and decrease in reflectance due to coarsening of crystal grains. In view of this, the team of the present invention set about investigating a silver alloy reflective layer having a small degree of decrease in the reflectance of the reflective layer even if the number of writes, reads, and erases is greatly increased. The obtained research results are as follows: (0 uses: 0.5 to 3% by weight of Cu; and a total of 0.1 to 3% by weight of one or more selected from Dy, La, Nd, Tb, Gd; and the remaining A silver alloy sputtering target composed of silver is used. The silver alloy reflection layer obtained by sputtering is used. Since the silver alloy reflection layer is seldom coarse in crystal grains caused by heating and cooling after repeated irradiation with laser light, even if it is long, The phenomenon of decreasing the reflectance caused by time use is extremely limited. (B) One or two or more selected from Ca, Be, and Si in a total of 0.005 to 0.05% by weight; And the remaining part is a silver alloy sputtering target composed of silver. The silver alloy reflective layer obtained by sputtering is used. Since the silver alloy reflective layer is seldom coarse in crystal grains caused by heating and cooling after repeated irradiation with laser light, Even if it is used for a long time, the phenomenon of the decrease in reflectance is extremely limited. (C) Even if it contains at least 0.1 to 3% by weight of the above, one or two or more selected from Dy, La, Nd, Tb, and Gd; and total 0.005 ~ 0.05% by weight One or two of Ca, Be, and Si are selected as above (3) 200417620, and the same effect is obtained. The present invention is based on related research results, and (1) is 0.5 to 3% by weight Cu; and a total of 0 consisting of one or two selected from Dy, La, Nd, Tb, and Gd as silver, and used to form an anti-sputter target for an optical recording medium. (2) 0.5 to 3% by weight Cu; and a total of 0.% of Ca, Be, and Si selected from one or more of silver is used to form a reflective layer target for optical recording media. (3) 0.5 to 3% by weight of Cu ; And a total of 0 or 1 or 2 from Dy, La, Nd, Tb, or Gd; 0.005 to 0.05% by weight; selected from Ca, Be, or Si; and the remainder is silver The composition is used to form a silver alloy sputtering target for forming an optical memory layer. The sputtering method used to form a silver alloy reflection layer in the present invention is obtained by using Cu, Dy, La having a purity of more than 99.99% by weight and up to 99.99% by weight. Nd is the raw material 'and after the high vacuum or the aforementioned raw material is melted, the molten raw material obtained by the high vacuum or the passivation gas ring casting is also cast into an ingot, Manufactured by mechanical processing after the aforementioned hot work. Ca, Be, and Si that are hardly solid-solved in Ag are obtained by bursting. 1-3% by weight or more; and silver alloy with remaining shots. 0 5 to 0.0 5; and the rest of the silver alloy sputtering. 1 to 3% by weight or more; and a total of 1 or 2 types of reflective targets for recording media can be made of the following silver; and purity, Tb and Gd are blunt Under the gas environment, the aforementioned molten ingot is thermally processed in the environment so that the element (4) (4) 200417620 is formed into 0.20% by weight and mixed with Ag and then melted by means of high-frequency vacuum melting. Inject Ar gas into the melting furnace After the pressure in the furnace returns to the atmospheric pressure, it is cast into a master alloy containing Ca, Be and Si using a graphite mold, and the aforementioned master alloy and Cu are simultaneously melted to find an ingot. The ingot is hot-worked and manufactured by machining. Next, the reason why the aforementioned composition is restricted for the reflective layer formed of the Ag alloy of the present invention and the sputtering target for forming the reflective layer formed of the silver alloy of the present invention will be described below.

Cu: Although Cu has the effects of increasing the strength of crystal grains, preventing the recrystallization of crystal grains, and suppressing the decrease in reflectance after solid solution in Ag, it will not be possible if the Cu content is less than 0.5% by weight. Even if the recrystallization of crystal grains is sufficiently prevented, the decrease in reflectance cannot be suppressed together, and further, if the Cu content exceeds 3% by weight, the initial reflectance of the Ag alloy reflective layer will be lowered, which is not suitable. Due to the above reasons, the Cu content in the Ag alloy reflective layer and the sputtering target used to form the reflective layer composed of the silver alloy in the present invention is limited to 0.5 to 3% by weight (among which 0.5 to 1.5% by weight is more Suitable).

Dy, La, Nd, Tb, Gd: Although each of the above components can react with Ag to form intermetallic compounds in the crystal grain boundary to prevent the bonding between crystal grains, it is capable of -8-(5) (5) 200417620 A component that further prevents the recrystallization of the Ag alloy reflection layer, but if the total content of one or two or more selected from the above components is less than 0.1% by weight, significant results will not be obtained. In addition, once the total content of one or two or more selected from the above-mentioned ingredients exceeds 3% by weight, the sputtering target is significantly hardened and it is difficult to manufacture, so it is not applicable. Due to the reasons mentioned above, the content of the above components in the Ag alloy reflective layer and the sputtering target used to form the silver alloy-based reflective layer in the present invention is limited to 0.1 to 3% by weight (among which 0.2 to 1.5 % By weight is more suitable). _

Ca, Be, Si: The above components are hardly solid-solved in Ag. Although it can prevent the bonding between crystal grains by precipitating from the crystal grain boundaries, it can further prevent the recrystallization of the Ag alloy reflection layer. Ingredients, but if the total content of one or more selected from the above ingredients is less than 0.005% by weight, significant effects will not be obtained. In addition, once one or two or more selected from the above ingredients are combined, If the content exceeds 0.05% by weight, the sputtering target will be significantly hardened and it will be difficult to manufacture, so it is not suitable. Due to the above reasons, the content of the above components in the Ag alloy reflective layer and the sputtering target used to form the reflective layer composed of the silver alloy in the present invention are limited to 0.005% ~ 0.05% by weight (wherein 0.010 ~ 0.035% by weight is more suitable). [Embodiment] Example 1 Prepare silver with a purity of up to 99.9% by weight or more; and a purity of up to -9-(6) 200417620 99.99% by weight or more of Cu, Dy, La, Nd, Tb, and Gd, using high vacuum The melting furnace melts the aforementioned raw materials, casts the molten raw materials obtained by the aforementioned melting into an ingot under an Ar ^ environment, and heats the aforementioned ingots at a temperature of ° C for 2 hours and then performs rolling to form them by mechanical processing. Sputtering targets 1 to 2 of the present invention having a diameter of 1 2 5 faces and a thickness of 5 mm and having the components shown in * 1 to 2 are also produced. At the same time, sputtering targets 1 to 7 and conventional sputtering targets are also produced. The sputtering targets 1 to 22, the pair of sputtering targets 1 to 7, and the conventional sputtering targets of the present invention are respectively soldered to a bottom made of oxygen-free high-conductivity copper by soldering, and then installed in a DC magnetic sputtering device. Then, the gas was evacuated in a vacuum exhaust device to form 1 X 1 0_4P a inside the DC magnetic sputtering device, and then Ar gas was formed to form a sputtering pressure of OPa. Next, a sputtering target was passed through a power source with a power of 100 W. The DC sputtering power is used to form a plasma between the aforementioned target and a glass substrate with a diameter of 30 mm and a thickness of 5 min, which are arranged to form a confrontation with the aforementioned sputtering target, and are parallel to each other through 70 mm. 100nm silver alloy reflective film. The reflectance of each silver alloy reflective film formed as described above was measured by a spectrometer after the film was formed. Later, after each of the foregoing silver-coated films was placed in a constant temperature and humidity bath at a temperature of 80 ° C and a relative humidity of 85%, the reflectance was measured under the same conditions. Based on the measured emissivity data, the reflectances at 400nm and 65nm are calculated, as shown in Tables 1 and 2, and the reading and writing resistance of the reflective film of the optical recording medium is evaluated based on this. The original 600 is connected as shown below. The surface of the photo group is placed inside the plate, and the direct current sputtering interval is the opposite result of the photometric gold reverse 200 200417620 \) / (5if ^ Ms 盘 muos9 ^^ 0 # h / `` / Oo (ns 96 96 96 ε6 (N6 06 96 96 (N6 $ 6 Z6 J ^, 1 ^ 1 & ISM- L6 L6 96 S6 inch 6 rn6 L6 96 inch 6 L6 inch 6 1 ^ 1 1 ^, (% ) 10 ^ 0 # Θ, Γ, 00 (N_ 0000 L% inch 00

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-12- 200417620 〇) According to the results shown in Table 1, it can be clearly understood that the sputtering target 1 of the present invention is used after being left in a constant temperature and humidity tank at a temperature of 80 ° C and a relative humidity of 8 5% for 200 hours. ~ 22 The decrease in the reflectance of the reflective layer obtained by performing sputtering is much lower than the decrease in the reflectance of the reflective layer obtained by sputtering using a control group sputtering target and a conventional sputtering target. Example 2 Ag, Cu, Ca, Be, and Si having a purity of 99.99% by weight or more were prepared. Ca, Be, and Si are hardly solid-solved in Ag. Therefore, 0.20% by weight of the element is mixed with Ag and melted by high-frequency vacuum melting. At * gas is injected into the melting furnace until the pressure in the furnace is restored. After the state of atmospheric pressure, it was cast into a master alloy containing Ca, Be, and Si using a graphite mold. The aforesaid master alloy and Cu are simultaneously mixed into Ag and then melted and cast into an ingot, and the ingot is heated at a temperature of 600 □ for 2 hours and then rolled, and then the diameter is formed by machining. The sputtering target 2 3 to 36 of the present invention having a thickness of 5 legs and a thickness of 5 legs and having the composition shown in Tables 3 to 4 was also manufactured, and a control group sputtering target 8 to 13 was also produced. The sputtering targets 23 to 36 of the present invention and the control group sputtering targets 8 to 13 obtained in the above manner were subjected to the same treatment as in Example 1 to form a silver alloy with a thickness of 100 nm on a glass substrate. Reflective film, and use a spectrophotometer to measure its reflectance after film formation. Later, after each of the foregoing silver alloy reflection films were placed in a constant temperature and humidity bath at a temperature of 80 □ and a relative humidity of 85%, the reflectance was measured under the same conditions for 200 hours. Based on the measured reflectance data of -13- (10) 200417620, the reflectances at 400nm and 650nm are calculated. The results are shown in Tables 3 to 4, and the reading and writing resistance of the reflective film of the optical recording medium is calculated accordingly. Make a comparison.

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-16- (13) (13) 200417620 According to the results shown in Tables 3 to 4, it can be clearly known that after being placed in a constant temperature and humidity tank at a temperature of 80 ° C and a relative humidity of 85% for 200 hours, use The decrease in the reflectance of the reflective layer obtained by performing sputtering of the sputtering targets 23 to 36 of the present invention is much lower than that of the control sputtering targets 8 to 13 shown in Table 4 and the conventional sputtering shown in Table 2. The reflectance of the reflective layer obtained by sputtering the target decreases. Example 3 Using the raw materials prepared in Example 1 and the master alloy containing Ca, Be, and Si in Example 2, a sputtering target 37 to 50 of the present invention having the composition shown in Table 5 was prepared. After each sputtering target was treated in the same manner as in Example 1, a silver alloy reflective film having a thickness of 1000 nm was formed on a glass substrate, and the reflectance was measured after the film was formed using a spectrophotometer. Later, after each of the foregoing silver alloy reflective films was placed in a constant temperature and humidity tank at a temperature of 80 □ and a relative humidity of 85% for 200 hours, the reflectance was measured under the same conditions. Based on the measured reflectance data, the reflectances at 400 nm and 65 Onm were calculated. The results are shown in Table 5 and the read / write resistance of the reflective film of the optical recording medium was evaluated accordingly. 200417620 \ 1 /) sssmuos9 ¥ ^ s £ ', r, oo (N_ L6 96 S6 S6 inch 6 S6 96 16 < n6 S6 inch 6 Z6 16 disc chain 辁 L6 96 56 S6 inch 6 96 L6 S6 Γη6 rn6 L6 56 inch 6 Zn6) `` f ^ Ms # 0 SU0017¾¾ 0 # 0,1 / 00 < Niy & Can dye 鲣 gy 900 L% soo (Noo εοο 100 soo L% (Noo 98 18

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O -18- (15) (15) 200417620 According to the results shown in Table 5, it can be clearly understood that the present invention is applied after being left in a constant temperature and humidity tank at a temperature of 80 ° C and a relative humidity of 8 5% for 200 hours. The decrease in the reflectance of the reflective layer obtained by performing sputtering on the sputtering targets 37 to 50 is much lower than using the conventional sputtering targets shown in Table 2 and the control group sputtering targets 8 to 1 shown in Table 4. 3 Decrease in reflectance of the reflective layer obtained by sputtering [Industrial Applicability] As described above, compared with the reflective layer made of a silver alloy sputtering target that is conventionally used to make a reflective layer of an optical recording medium The reflection layer made of the silver alloy sputtered IG used for forming the reflection layer of the optical recording medium of the present invention does not cause a decrease in reflectance due to time change, and can manufacture an optical recording medium suitable for long-term use. Has made a significant contribution to the development of the media industry 19-

Claims (1)

200417620 ⑴ Pickup, patent application scope 1. A silver alloy sputtering target for forming a reflective layer of an optical recording medium, made of: Cu: 0.5 to 3% by weight; and one selected from Dy, La, Nd, Tb, and Gd Or two or more kinds, totaling 0.1 to 3% by weight; and the remainder is composed of silver. 2 · —A silver alloy sputtering target for forming a reflective layer of an optical recording medium is composed of: Cu: 0.5 to 3% by weight: and one or two or more selected from Ca, Be, and Si, for a total of 0 · 005 to 0.05% by weight; and the remainder is composed of silver. 3. A silver alloy sputtering target for forming a reflective layer of an optical recording medium, consisting of: Cu: 0.5 to 3% by weight; and One or two or more selected from Dy, La, Nd, Tb, or Gd, totaling 0.1 to 3% by weight; and one or two or more selected from Ca, Be, and Si, totaling 0.5 to 5. · 5% by weight; and the remainder is composed of silver. 4. A reflective layer for an optical recording medium is made by using a silver alloy sputtering target for forming a reflective layer of an optical recording medium as described in item 1, 2 or 3 of the scope of patent application. -20-200417620 Lu, (1), the designated representative of the case is: None (2), the representative symbol of the component of the circle is simply explained: None 柒 、 If there is a chemical formula in this case, please disclose the chemical formula that can best show the characteristics of the invention ... 3