Sputtering Target, Thin Film for Optical Information Recording Medium and Process for Producing the Same

• US 20100240521A1
• Filed: 06/04/2010
• Published: 09/23/2010
• Est. Priority Date: 03/04/2003
• Status: Active Grant

• Current Assignee: JX Nippon Mining & Metals Corporation (ENEOS Holdings, Inc.)
• Original Assignee: Nippon Light Metal Company Limited (Nippon Light Metal Holdings Co., Ltd.)
• Inventors: Takami, Hideo, Yahagi, Masataka, Hosono, Hideo, Ueda, Kazushige
• Granted Patent: US 7,897,068 B2
• Time in Patent Office: Days
• US Class Current: 501/153
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3272 Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite
• CPC Class Codes: C04B 2235/3284 Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
• CPC Class Codes: C04B 2235/3286 Gallium oxides, gallates, indium oxides, indates, thallium oxides, thallates or oxide forming salts thereof, e.g. zinc gallate
• CPC Class Codes: C04B 2235/3293 Tin oxides, stannates or oxide forming salts thereof, e.g. indium tin oxide [ITO]
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/775 Products showing a density-gradient
• CPC Class Codes: C04B 35/453 based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates
• CPC Class Codes: C23C 14/086 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: G11B 2007/25706 containing transition metal elements (Zn, Fe, Co, Ni, Pt)
• CPC Class Codes: G11B 2007/25708 containing group 13 elements (B, Al, Ga)
• CPC Class Codes: G11B 2007/2571 containing group 14 elements except carbon (Si, Ge, Sn, Pb)
• CPC Class Codes: G11B 2007/25715 containing oxygen
• CPC Class Codes: G11B 7/2531 comprising glass
• CPC Class Codes: G11B 7/2578 consisting essentially of inorganic materials
• CPC Class Codes: G11B 7/266 Sputtering or spin-coating layers sputtering in general C23C14/24; spin-coating in general B05D1/005
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft
• CPC Class Codes: Y10T 428/12 : All metal or with adjacent metals

Abstract

A sputtering target is provided that has a relative density of 80% or more and contains a compound having as its principal component zinc oxide satisfying A_XB_YO_(KaX+KbY)/2(ZnO)_m, 1<m, X<m, 0≦Y≦0.9, X+Y=2, where A and B are respectively different positive elements of trivalence or more, and the valencies thereof are respectively Ka and Kb. A ZnO based sputtering target is obtained which does not contain ZnS and SiO₂, and, upon forming a film via sputtering, is capable of reducing the affect of heating the substrate, of performing high speed deposition, of adjusting the film thickness to be thin, of reducing the generation of particles (dust) and nodules during sputtering, of improving the productivity with small variation in quality, and which has fine crystal grains and a high density of 80% or more, particularly 90% or more.

Claims

1. A thin film for an optical information recording medium prepared by a process comprising the step of forming the thin film by sputtering a sputtering target that is a sintered compact of powder having an average grain size of 1 μ

m or less before sintering, that has a relative density of 90% or more, and that contains a compound having as its principal component zinc oxide satisfying A_XB_YO_(KaX+KbY)/2(ZnO)_m, wherein 1<

m, X<

m, 0<

Y≦

0.9, and X+Y=2, and where A and B are respectively different positive elements of trivalence or more, and the valencies thereof are respectively Ka and Kb, and wherein a range of variation of positive elements other than zinc in the target is within 0.5% and a range of variation of density in the target is within 3%.

2. A thin film according to claim 1, wherein m is equal to or greater than 4.

3. A thin film according to claim 2, where m is an integral number.

4. A thin film according to claim 1, where m is an integral number.

5. A thin film according to claim 1, wherein said thin film is amorphous and stably retains an amorphous nature when heated to 600°

C.

6. A thin film according to claim 5, wherein optical characteristics of said thin film include a transmittance of 90% to 99% and a refractive index of 1.9 to 2.3.

7. A thin film for being located adjacent a reflective layer or a recording layer of an optical information recording medium, comprising:

a thin film that is formed by sputtering and that is made of a compound having as its principal component zinc oxide satisfying A_XB_YO_(KaX+KbY)/2(ZnO)_m, where 1<

m, X<

m, 0<

Y≦

0.9, and X+Y=2, and where A and B are respectively different positive elements of trivalence or more, and the valencies thereof are respectively Ka and Kb;

said thin film being amorphous and stably retaining an amorphous nature when heated to 600°

C.

8. A thin film according to claim 7, wherein said thin film has a transmittance of 90% to 99%.

9. A thin film according to claim 8, wherein said thin film has a refractive index of 1.9 to 2.3.

10. A thin film according to claim 7, wherein said thin film has a transmittance of 90% to 99% at a wavelength of 650 nm.

11. A thin film according to claim 10, wherein said thin film has a refractive index of 1.9 to 2.3 at a wavelength of 633 nm.

12. A thin film according to claim 7, wherein said amorphous nature of said thin film is such that said thin film has a maximum peak intensity ratio against an undeposited glass substrate in 2θ

=20 to 60°

measured by XRD of 1.0 to 1.6.