High-strength sputtering target for forming protective film for optical recording medium

The ZrO 2 powder, amorphous SiO 2 powder, crystalline SiO 2 powder, and Al 2 O 3 powder were weighed to give the composition shown in Table 1 and uniformly mixed by a Henschel mixer. Subsequently, the mixed powder was press-molded, after which the obtained molded body was baked under the conditions given in Table 1, thereby producing an inventive target 1 and a conventional target 1, both of which had a diameter of 200 mm and a thickness of 6 mm and included 30% of ZrO 2 , and 20% of SiO 2 , and the remainders containing Al 2 O 3 . The cross sections of the target 1 of the present invention and the conventional target 1 were polished and observed through X-ray diffraction and an EPMA to determine whether or not a complex oxide phase of Al 6 Si 2 O 13 was formed in the bases of the targets. The results of which are given in Table 1. Furthermore, the density and flexural strength of the target 1 of the present invention and the conventional target 1 were measured. The results are shown in Table 1.

Then, the produced target 1 of the present invention and the produced conventional target 1 were mounted in a direct current magnetron sputtering system, in a state of being soldered with a water-cooled backing plate made of oxygen-free copper. First, the inside of the system was evacuated to be 1×10 −6 Torr or less using a vacuum air exhauster. Then, an Ar gas was introduced into the system so as to give a pressure of sputtering gas of 1.5×10 −3 Torr. A polycarbonate substrate with a thickness of 0.6 mm was disposed at an interval of 70 mm, i.e., the interval of the targets. In this state, a direct current power, i.e., a sputtering power of 9 kW which was higher than the norm, was applied, and protective films for an optical recording medium, having a thickness of 50 nm, were formed on a surface of the polycarbonate substrate, using the target 1 of the present invention and the conventional target 1, respectively. Here, observation to determine whether or not cracks are formed in the targets was made. The results of which are shown in Table 1.

The results given in Table 1 show that the target 1 of the present invention in which the complex oxide phase of Al 6 Si 2 O 13 was formed in the base has a higher density and strength and does not give cracks upon sputtering as compared to the conventional target 1 in which the complex oxide phase of Al 6 Si 2 O 13 was not formed in the base, even if both had the same composition.

The HfO 2 powder, amorphous SiO 2 powder, crystalline SiO 2 powder, and Al 2 O 3 powder were weighed to give the composition shown in Table 2 and uniformly mixed by a Henschel mixer. Subsequently, the mixed powder was press-molded, after which the obtained molded body was baked under the conditions given in Table 2, thereby producing an inventive target 2 and a conventional target 2, both of which had a diameter of 200 mm and a thickness of 6 mm and included 30% of HfO 2 , and 20% of SiO 2 , and the remainders containing Al 2 O 3 . The cross sections of the target 2 of the present invention and the conventional target 2 were polished and observed through X-ray diffraction and an electron probe micro analyzer (EPMA) to determine whether or not a complex oxide phase of Al 6 Si 2 O 13 was formed in the bases of the targets, the results of which are given in Table 2. Furthermore, the density and flexural strength of the target 2 of the present invention and the conventional target 2 were measured. The results are shown in Table 2.

Then, the produced target 2 of the present invention and the produced conventional target 2 were mounted in a direct current magnetron sputtering system, in a state of being soldered with a water-cooled backing plate made of oxygen-free copper. First, the inside of the system was evacuated to be 1×10 −6 Torr or less using a vacuum air exhauster. Then, an Ar gas was introduced into the system so as to give a pressure of sputtering gas of 1.5×10 −3 Torr. A polycarbonate substrate with a thickness of 0.6 mm was disposed at an interval of 70 mm, i.e., the interval of the targets. In this state, direct current power, i.e., a sputtering power of 7 kW which was higher than norm, was applied, and protective films for an optical recording medium, having a thickness of 50 nm, were formed on a surface of the polycarbonate substrate, using the target 2 of the invention and the conventional target 2, respectively. Here, observation to determine whether or not cracks are formed in the targets was made. The results of which are shown in Table 2.

The results given in Table 2 show that the target 2 of the present invention in which the complex oxide phase of Al 6 Si 2 O 13 was formed in the base has a higher density and strength and does not give cracks upon sputtering as compared to the conventional target 2 in which the complex oxide phase of Al 6 Si 2 O 13 was not formed in the base, even if both had the same composition.

The stabilizer ZrO 2 powder containing 3 mol % of Y 2 O 3 , amorphous SiO 2 powder, crystalline SiO 2 powder, and Al 2 O 3 powder were weighed to give the composition given in Table 3 and uniformly mixed by a Henschel mixer. Subsequently, the mixed powder was press-molded, after which the obtained molded body was baked under the conditions given in Table 3, thereby producing a target 3 of the present invention and a conventional target 3, both of which had a diameter of 200 mm and a thickness of 6 mm and included 30% of ZrO 2 , and 0.9% of Y 2 O 3 , 20% of SiO 2 , and the remainders containing Al 2 O 3 . The cross sections of the target 3 of the present invention and the conventional target 3 were polished and observed through X-ray diffraction and an electron probe micro analyzer (EPMA) to determine whether or not a complex oxide phase of Al 6 Si 2 O 13 was formed in the bases of the targets, the results of which are given in Table 3. Furthermore, the density and flexural strength of the target 3 of the present invention and the conventional target 3 were measured. The results are shown in Table 3.

Then, the produced target 3 of the present invention and the produced conventional target 3 were mounted in a direct current magnetron sputtering system, in a state of being soldered with a water-cooled backing plate made of oxygen-free copper. First, the inside of the system was evacuated to be 1×10 −6 Torr or less using a vacuum air exhauster. Then, an Ar gas was introduced into the system so as to give a pressure of sputtering gas of 1.5×10 −3 Torr. A polycarbonate substrate with a thickness of 0.6 mm was disposed at an interval of 70 mm, i.e., the interval of the targets. In this state, a direct current power, i.e., a sputtering power of 9 kW which was higher than the norm, was applied, and protective films for an optical recording medium, having a thickness of 50 nm, were formed on the polycarbonate substrate, using the target 3 of the present invention and the conventional target 3, respectively. Here, observation to determine whether or not cracks are formed in the targets was made. The results of which are shown in Table 3.

The results given in Table 3 show that the target 3 of the present invention in which the complex oxide phase of Al 6 Si 2 O 13 was formed in the base has a higher density and strength and does not give upon sputtering as compared to the conventional target 3 in which the complex oxide phase of Al 6 Si 2 O 13 was not formed in the base, even if both had the same composition.

The ZrO 2 powder, amorphous SiO 2 powder, crystalline SiO 2 powder, and La 2 O 3 powder were weighed to give the composition given in Table 4 and uniformly mixed by a Henschel mixer. Subsequently, the mixed powder was press-molded, after which the obtained molded body was baked under the conditions given in Table 4, thereby producing a target 4 of the present invention and a conventional target 4, both of which had a diameter of 200 mm and a thickness of 6 mm and included 30% of ZrO 2 , and 20% of SiO 2 , and remainders containing La 2 O 3 . The cross sections of the target 4 of the present invention and the conventional target 4 were polished and observed through X-ray diffraction and an electron probe micro analyzer (EPMA) to determine whether or not a complex oxide phase of La 2 SiO 5 was formed in the bases of the targets. The results of which are given in Table 4. Furthermore, the density and flexural strength of the target 4 of the present invention and the conventional target 4 were measured. The results are shown in Table 4.

Then, the produced target 4 of the present invention and the produced conventional target 4 were mounted in a direct current magnetron sputtering system, in a state of being soldered with a water-cooled backing plate made of oxygen-free copper. First, the inside of the system was evacuated to be 1×10 −6 Torr or less using a vacuum air exhauster. Then, an Ar gas was introduced into the system so as to give a pressure of sputtering gas of 1.5×10 −3 Torr. A polycarbonate substrate with a thickness of 0.6 mm was disposed at an interval of 70 mm, i.e., the interval of the targets. In this state, a direct current power, i.e., a sputtering power of 9 kW which was higher than the norm, was applied, and protective films for an optical recording medium, having a thickness of 50 nm, were formed on a surface of the polycarbonate substrate, using the target 4 of the present invention and the conventional target 4, respectively. Here, observation to determine whether or not cracks are formed in the targets was made. The results of which are shown in Table 4.

The results given in Table 4 show that the target 4 of the present invention in which the complex oxide phase of La 2 SiO 5 was formed in the base has a higher density and strength and does not give cracks upon sputtering as compared to the conventional target 4 in which the complex oxide phase of La 2 SiO 5 was not formed in the base, even if both had the same composition.

The HfO 2 powder, amorphous SiO 2 powder, crystalline SiO 2 powder, and La 2 O 3 powder were weighed to give the composition given in Table 5 and uniformly mixed by a Henschel mixer. Subsequently, the mixed powder was press-molded, after which the obtained molded body was baked under the conditions given in Table 5, thereby producing a target 5 of the present invention and a conventional target 5, both of which had a diameter of 200 mm and a thickness of 6 mm and included 30% of HfO 2 , and 20% of SiO 2 , and the remainders containing La 2 O 3 . The cross sections of the target 5 of the present invention and the conventional target 5 were polished and observed through X-ray diffraction and an electron probe micro analyzer (EPMA) to determine whether or not a complex oxide phase of La 2 SiO 5 was formed in the bases of the targets. The results of which are given in Table 5. Furthermore, the density and flexural strength of the target 5 of the present invention and the conventional target 5 were measured. The results of which are shown in Table 5.

Then, the produced target 5 of the present invention and the produced conventional target 5 were mounted in a direct current magnetron sputtering system, in a state of being soldered with a water-cooled backing plate made of oxygen-free copper. First, the inside of the system was evacuated to be 1×10 −6 Torr or less using a vacuum air exhauster. Then, an Ar gas was introduced into the system so as to give a pressure of sputtering gas of 1.5×10 −3 Torr. A polycarbonate substrate with a thickness of 0.6 mm was disposed at an interval of 70 mm, i.e., the interval of the targets. In this state, a direct current power, i.e., a sputtering power of 7 kW which was higher than the norm, was applied, and protective films for an optical recording medium, having a thickness of 50 nm, were formed on a surface of the polycarbonate substrate, using the target 5 of the present invention and the conventional target 5, respectively. Here, observation to determine whether or not cracks are formed in the targets was made. The results of which are shown in Table 5.

The results given in Table 5 show that the target 5 of the present invention in which the complex oxide phase of La 2 SiO 5 was formed in the base has a higher density and strength and does not give cracks upon sputtering as compared to the conventional target 5 in which the complex oxide phase of La 2 SiO 5 was not formed in the base, even if both had the same composition.

The stabilizer ZrO 2 powder containing 3 mol % of Y 2 O 3 , amorphous SiO 2 powder, crystalline SiO 2 powder, and La 2 O 3 powder were weighed to give the composition shown in Table 6 and uniformly mixed by a Henschel mixer. Subsequently, the mixed powder was press-molded, after which the obtained molded body was baked under the condition given in Table 6, thereby producing a target 6 of the present invention and a conventional target 6, both of which had a diameter of 200 mm and a thickness of 6 mm and included 30% of ZrO 2 , and 0.9% of Y 2 O 3 , 20% of SiO 2 and the remainders containing La 2 O 3 . The cross sections of the target 6 of the present invention and the conventional target 6 were polished and observed through X-ray diffraction and an electron probe micro analyzer (EPMA) to determine whether or not a complex oxide phase of La 2 SiO 5 was formed in the bases of the targets. The results of which are given in Table 6. Furthermore, the density and flexural strength of the target 6 of the present invention and the conventional target 6 were measured. The results are shown in Table 6.

Then, the produced target 6 of the present invention and the produced conventional target 6 were mounted in a direct current magnetron sputtering system, in a state of being soldered with a water-cooled backing plate made of oxygen-free copper. First, the inside of the system was evacuated to be 1×10 −6 Torr or less using a vacuum air exhauster. Then, an Ar gas was introduced into the system so as to give a pressure of sputtering gas of 1.5×10 −3 Torr. A polycarbonate substrate with a thickness of 0.6 mm was disposed at an interval of 70 mm, i.e., the interval of the targets. In this state, a direct current power, i.e., a sputtering power of 9 kW which was higher than the norm, was applied, and protective films for an optical recording medium, having a thickness of 50 nm, were formed on a surface of the polycarbonate substrate, using the target 6 of the present invention and the conventional target 6, respectively. Here, observation to determine whether or not cracks are formed in the targets was made. The results of which are shown in Table 6.

The results given in Table 6 show that the target 6 of the present invention in which the complex oxide phase of La 2 SiO 5 was formed in the base has a higher density and strength and does not give cracks upon sputtering as compared to the conventional target 6 in which the complex oxide phase of La 2 SiO 5 was not formed in the base, even if both had the same composition.

The ZrO 2 powder, amorphous SiO 2 powder, crystalline SiO 2 powder, and In 2 O 3 powder were weighed to give the composition shown in Table 7 and uniformly mixed by a Henschel mixer. Subsequently, the mixed powder was press-molded, after which the obtained molded body was baked under the condition given in Table 7, thereby producing a target 7 of the present invention and a conventional target 7, both of which had a diameter of 200 mm and a thickness of 6 mm and included 30% of ZrO 2 , and 20% of SiO 2 , and the remainders containing In 2 O 3 . The cross sections of the target 7 of the present invention and the conventional target 7 were polished and observed through X-ray diffraction and an electron probe micro analyzer (EPMA) to determine whether or not a complex oxide phase of In 2 Si 2 O 7 was formed in the bases of the targets. The results of which are given in Table 7. Furthermore, the density and flexural strength of the target 7 of the present invention and the conventional target 7 were measured. The results of which are shown in Table 7.

Then, the produced target 7 of the present invention and the produced conventional target 7 were mounted in a direct current magnetron sputtering system, in a state of being soldered with a water-cooled backing plate made of oxygen-free copper. First, the inside of the system was evacuated to be 1×10 −6 Torr or less using a vacuum air exhauster. Then, an Ar gas was introduced into the system so as to give a pressure of sputtering gas of 1.5×10 −3 Torr. A polycarbonate substrate with a thickness of 0.6 mm was disposed at an interval of 70 mm, i.e., the interval of the targets. In this state, a direct current power, i.e., a sputtering power of 9 kW which was higher than the norm, was applied, and protective films for an optical recording medium, having a thickness of 50 nm, were formed on a surface of the polycarbonate substrate, using the target 7 of the present invention and the conventional target 7, respectively. Here, observation to determine whether or not cracks are formed in the targets was made. The results of which are shown in Table 7.

The results given in Table 7 show that the target 7 of the present invention in which the complex oxide phase of In 2 Si 2 O 7 was formed in the base has a higher density and strength and does not give cracks upon sputtering as compared to the conventional target 7 in which the complex oxide phase of In 2 Si 2 O 7 was not formed in the base, even if both had the same composition.

The HfO 2 powder, amorphous SiO 2 powder, crystalline SiO 2 powder, and In 2 O 3 powder were weighed to give the composition shown in Table 8 and uniformly mixed by a Henschel mixer. Subsequently, the mixed powder was press-molded, after which the obtained molded body was baked under the conditions given in Table 8, thereby producing a target 8 of the present invention and a conventional target 8, both of which had a diameter of 200 mm and a thickness of 6 mm and included 30% of HfO 2 , and 20% of SiO 2 , and the remainders containing In 2 O 3 . The cross sections of the target 8 of the present invention and the conventional target 8 were polished and observed through X-ray diffraction and an electron probe micro analyzer (EPMA) to determine whether or not a complex oxide phase of In 2 Si 2 O 7 was formed in the bases of the target. The results of which are given in Table 8. Furthermore, the density and flexural strength of the target 8 of the present invention and the conventional target 8 were measured. The results are shown in Table 8.

Then, the produced target 8 of the present invention and the produced conventional target 8 were mounted in a direct current magnetron sputtering system, in a state of being soldered with a water-cooled backing plate made of oxygen-free copper. First, the inside of the system was evacuated to be 1×10 −6 Torr or less using a vacuum air exhauster. Then, an Ar gas was introduced into the system so as to give a pressure of sputtering gas of 1.5×10 −3 Torr. A polycarbonate substrate with a thickness of 0.6 mm was disposed at an interval of 70 mm, i.e., the interval of the targets. In this state, a direct current power, i.e., a sputtering power of 7 kW which was higher than the norm, was applied, and protective films for an optical recording medium, having a thickness of 50 nm, were formed on a surface of the polycarbonate substrate, using the target 8 of the present invention and the conventional target 8, respectively. Here, observation to determine whether or not cracks are formed in the targets was made. The results of which are shown in Table 8.

The results given in Table 8 show that the target 8 of the present invention in which the complex oxide phase of In 2 Si 2 O 7 was formed in the base has a higher density and strength and does not give cracks upon sputtering as compared to the conventional target 8 in which the complex oxide phase of In 2 Si 2 O 7 was not formed in the base, even if both had the same composition.

The stabilizer ZrO 2 powder containing 3 mol % of Y 2 O 3 , amorphous SiO 2 powder, crystalline SiO 2 powder, and In 2 O 3 powder were weighed to give the composition shown in Table 9 and uniformly mixed by a Henschel mixer. Subsequently, the mixed powder was press-molded, after which the obtained molded body was baked under the condition given in Table 9, thereby producing a target 9 of the present invention and a conventional target 9, both of which had a diameter of 200 mm and a thickness of 6 mm and included 30% of ZrO 2 , 0.9% of Y 2 O 3 , and 20% of SiO 2 and the remainders containing In 2 O 3 . The cross sections of the target 9 of the present invention and the conventional target 9 were polished and observed through X-ray diffraction and an electron probe micro analyzer (EPMA) to determine whether or not a complex oxide phase of In 2 Si 2 O 7 was formed in the bases of the targets. The results of which are given in Table 9. Furthermore, the density and flexural strength of the target 9 of the present invention and the conventional target 9 were measured. The results are shown in Table 9.

Then, the produced target 9 of the present invention and the produced conventional target 9 were mounted in a direct current magnetron sputtering system, in a state of being soldered with a water-cooled backing plate made of oxygen-free copper. First, the inside of the system was evacuated to be 1×10 −6 Torr or less using a vacuum air exhauster. Then, an Ar gas was introduced into the system so as to give a pressure of sputtering gas of 1.5×10 −3 Torr. A polycarbonate substrate with a thickness of 0.6 mm was disposed at an interval of 70 mm, i.e., the interval of the targets. In this state, a direct current power, i.e., a sputtering power of 9 kW which was higher than the norm, was applied, and protective films for an optical recording medium, having a thickness of 50 nm, were formed on a surface of the polycarbonate substrate, using the target 9 of the present invention and the conventional target 9, respectively. Here, observation to determine whether or not cracks are formed in the targets was made. The results of which are shown in Table 9.

The results given in Table 9 show that the target 9 of the present invention in which the complex oxide phase of In 2 Si 2 O 7 was formed in the base has a higher density and strength and does not give cracks upon sputtering as compared to the conventional target 9 in which the complex oxide phase of In 2 Si 2 O 7 was not formed in the base, even if both had the same composition.

As described above, a target for forming a protective film for an optical recording medium according to the present invention can be formed in a large size due to even more improved strength. Moreover, as cracks do not form in the target even under high-power sputtering, a protective film for an optical recording medium can be formed more efficiently. Accordingly, the present invention is substantially useful for industrial applications.