Sputtering target, thin film for optical information recording medium and process for producing the same

• US 7,892,457 B2
• Filed: 03/11/2010
• Issued: 02/22/2011
• Est. Priority Date: 03/04/2003
• Status: Active Grant

• Current Assignee: JX Nippon Mining & Metals Corporation (ENEOS Holdings, Inc.)
• Original Assignee: JX Nippon Mining & Metals Corporation (ENEOS Holdings, Inc.)
• Inventors: Ueda, Kazushige, Takami, Hideo, Yahagi, Masataka, Hosono, Hideo
• Primary Examiner(s): MCGINTY, DOUGLAS J
• Application Number:
  US12/721,939
• Publication Number:
  US 20100167000A1
• Time in Patent Office: 348 Days
• Field of Search: 252/519.51, 252/519.5, 252/518.1, 252/519.1, 427/162, 427/248.1, 427/255.33, 427/126.3, 427/595, 427/580, 427/576, 427/587, 427/592, 427/593
• US Class Current: 252/519.51
• 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 method of manufacturing a thin film for an optical information recording medium comprising the step of forming a thin film via direct current sputtering of a sputtering target that has a relative density of 90% or more and that contains a homologous compound having as its principal component zinc oxide satisfying A_XByO_(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, 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 method according to claim 1, wherein m is equal to or greater than 4.

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

4. A method according to claim 2, wherein the film is located adjacent a recording layer of the optical information recording medium and forms a protective high-medium point dielectric thin film that is amorphous and stably retains an amorphous nature when heated to 600°

C. on the recording layer of the optical information recording medium.

5. A method according to claim 1, where m is an integral number.

6. A method according to claim 1, wherein the film is located adjacent a reflective layer or a recording layer of the optical information recording medium.

7. A method according to claim 1, wherein A and B are respectively different positive elements of trivalence.

8. A method according to claim 7, wherein A is indium (In) and B is selected from the group consisting of In, Al, Ga, In, Sc, Y, La and Fe.

9. A method of manufacturing a re-writable phase change optical information recording medium comprising the steps of:

providing a sputtering target that has a relative density of 90% or more and that consists of a homologous compound having as its principal component zinc oxide satisfying A_XB_YO₃(ZnO)_m, where m≧

4, 0<

Y≦

0.9, and X+Y=2, where A and B are respectively different positive elements of trivalence, and where a range of variation of the positive elements A and B in the target is within 0.5% and a range of variation of density in the target is within 3%; and

performing direct current (DC) sputtering of the sputtering target to form a protective high-melting point dielectric thin film that is amorphous and stably retains an amorphous nature when heated to 600°

C. on a recording layer of the re-writable phase change optical information recording medium.

10. A method according to claim 9, wherein A is Indium (In).

11. A method according to claim 10, wherein B is selected from the group consisting of Al, Ga, In, Sc, Y, La and Fe.

12. A method according to claim 11, wherein said direct current (DC) sputtering forms the protective high-melting point dielectric thin film such that the thin film has optical characteristics including a transmittance of 90% to 99% at a wavelength of 650 nm and a refractive index of 1.9 to 2.3 at a wavelength of 633 nm.