Metal treatment – Process of modifying or maintaining internal physical... – Treating loose metal powder – particle or flake
Patent
1998-06-12
2000-09-26
Wyszomierski, George
Metal treatment
Process of modifying or maintaining internal physical...
Treating loose metal powder, particle or flake
419 19, 419 68, 264122, B22F 904
Patent
active
061237876
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a process for manufacturing ITO (Indium-Tin-Oxyde) alloy articles, in particular pore free In.sub.2 O.sub.3 :Sn (indiumsesquioxyde:tin) articles for use as targets in plasma sputtering processes and machines (hereafter designated ISOT-articles, respectively ISOT-targets).
BACKGROUND OF THE INVENTION
It is known from DE 40 37 733 A1 to produce ITO-targets for plasma-sputtering purposes. A number of applications are cited for film substrates covered by plasma sputtering with thin ITO layers such as their use for touch panels. The targets are made by pressing and sintering a mixture of fine In.sub.2 O.sub.3 powder with fine SnO.sub.2 powder in an oxygen atmosphere. Although the so produced target has a high density, it has a relatively poor electrical conductivity so that it can only be used with low DC power densities in a DC-magnetron discharge.
OBJECTIVES AND BRIEF DESCRIPTION OF THE INVENTION
It is thus an objective of the invention to provide a pore free powder metallurgical alloy article with a proper proportion of In, Sn and oxygen and having a better conductivity. According to the invention the drawback of poor conductivity can be overcome if the tin (Sn) is added to the In.sub.2 O.sub.3 powder not in the form of an oxyde, but in its metallic state and if the metallic Sn phase can be maintained to a large extent throughout the manufacturing process of the pore free alloy article. A "pore free" metal powder alloy article means here an article with a density of at least 95% of the theoretical density of In.sub.2 O.sub.3.
It is another objective of the invention to use the article as a target in a plasma sputtering process and apparatus whereby the addition of reactive oxygen gas to the inert gas (in most cases argon) can be omitted or strongly reduced. This measure simplifies substantially the control of the sputtering process. The invention deals thus also with a plasma sputtering process, in particular a continuous process, and equipment for depositing ITO-compositions on a substrate wherein the target is sputtered off in an atmosphere comprising a stoechiometric ratio of at least 90% Ar and the balance oxygen gas. The substrate can be an elongated object such as a wire, filament, cord, yarn, strip, rod, tube or profile or a series of such objects in a parallel arrangement. The substrate can also be a planar object such as a foil, film, web, woven, braided, knitted or non woven fabric, plate or sheet. Depending on the shape of the substrate to be covered with the ITO composition the target can have a planar or tubular shape.
According to the invention these objectives are achieved by a process for manufacturing a pore free powder metallurgical alloy article starting with a minor portion of Sn powder and a major portion of In.sub.2 O.sub.3 powder and comprising the steps of
substantially uniformly distributing and fixing the Sn powder on the surface of the In.sub.2 O.sub.3 powder by mixing and milling the different powders in the presence of a process controlling agent to form alloyed powders and
compacting at high temperature the so alloyed powders to form the article.
The mixing and milling operation produces thereby a plastical kneading effect on the powders. For reasons of convenience, the pore free powder alloy and the derived article obtained by the process of the invention will be designated further on an ISOT-powder or ISOT-article.
The starting In.sub.2 O.sub.3 and Sn powders can have widely varying powder particle sizes. In.sub.2 O.sub.3 powder is normally produced by roasting In(OH).sub.3 and crushing the compound to the desired particle size, thereby forming particles with a rather irregular shape and a quite flaky aspect. Preferably, the average volume of an individual In.sub.2 O.sub.3 powder particle is larger than that of an individual Sn powder particle. The overall Sn content in the article is between 3% and 25 wt %, preferably between 8% and 15%, and the density after the final compacting is preferably at least 97% of the theoreti
REFERENCES:
patent: 4482374 (1984-11-01), Osborn et al
patent: 5094787 (1992-03-01), Nakajima et al.
patent: 5160675 (1992-11-01), Iwamoto et al
patent: 5480531 (1996-01-01), Weigert et al.
patent: 5480532 (1996-01-01), Schlott et al.
patent: 5522976 (1996-06-01), Campet t al.
Patent Abstracts of Japan vol. 018, No. 201 (C-1188), Apr. 8, 1994 & JP 06 002124 A (Mitsubishi Mat Corp), Jan. 11, 1994, see abstract.
Patent Abstracts of Japan vol. 14, No. 322 (C-0739), Jul. 10, 1990 & JP 02 115326 A (Mitsubishi Metal Corp), Apr. 27, 1990, see abstract.
Patent Abstracts of Japan vol.017, No. 678 (C-1141), Dec. 13, 1993 & JP 05 222526 A (Asahi Glass Co Ltd), Aug. 31, 1993, see abstract.
Database WPI Section Ch, Week 9309 Derwent Publications Ltd., London, GB; Class L02, AN 93-070896 XP002000037 & JP 05 017 201 A (Sumitomo Coal Mining Co Ltd), Jan. 26, 1993 see abstract.
Patent Abstracts of Japan vol. 18, No. 185 (C-1185), Mar. 30, 1994 & JP 05 339721 A (Mitsubishi Mat Corp), Dec. 21, 1993, see abstract.
Patent Abstract of Japan vol. 95, No. 1, Feb. 28, 1995 & JP 06 293963 A (Mitsui Mining & Smelting Co Ltd), Oct. 21, 1994, see abstract.
Patent Abstracts of Japan vol. 017, No. 577 (C-1122), Oct. 20, 1993 & JP 05 170513 A (Tosoh Corp), Jul. 9, 1993, see abstract.
Patent Abstracts of Japan vol. 017, No. 554 (C-1118), Oct. 6, 1993 & JP 05 156431 A (Asahi Glass Co Ltd), Jun. 22, 1993, see abstract.
Buekenhout Louis
Froyen Ludo
Lippens Paul
Innovative Sputtering Technology
Wyszomierski George
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