# US 8,784,729 B2 · High density refractory metals and alloys sputtering targets > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,729 B2 - Document ID: US8784729B2 - Status: Granted - Kind: B2 - Application number: 11/653,816 - Filed: 2007-01-16 - Published: 2008-07-17 - Granted: 2014-07-22 - Earliest claimed: 2007-01-16 - Assignees: H.C. Starck GmbH - Applicants: Prabhat Kumar; Charles Wood; Gary Rozak; Steven A. Miller; Glen Zeman; Rong-Chein Richard Wu - Inventors: Prabhat Kumar; Charles Wood; Gary Rozak; Steven A. Miller; Glen Zeman; Rong-Chein Richard Wu - Web page: https://patentgrep.com/patent/US8784729B2 ## CPC - C23C 14/3414: {Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy} - B22F 3/1017: {Multiple heating or additional steps (B22F3/101 takes precedence)} - B22F 2003/241: {Chemical after-treatment on the surface} - B22F 2003/247: {Removing material: carving, cleaning, grinding, hobbing, honing, lapping, polishing, milling, shaving, skiving, turning the surface} - B22F 2998/10: Processes characterised by the sequence of their steps - Y10T 428/12014: having metal particles - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The present invention is directed to a process for producing high density, refractory metal products via a press/sintering process. The invention is also directed to a process for producing a sputtering target and to the sputtering target so produced. ## Claims ### Claim 1 A method of forming a sputtering-target plate that is sputterable to form highly uniform, low-resistivity films of a refractory metal selected from the group consisting of molybdenum, tungsten, an alloy of molybdenum and tungsten, molybdenum alloyed with a metal other than tungsten, and tungsten alloyed with a metal other than molybdenum, the method comprising: cold isostatically pressing a powder of the refractory metal at a pressure selected from the range of 15,000 psi to 36,000 psi to form a pressed product; heating the pressed product under vacuum at a rate of about 20° F. to about 120° F. to a first temperature selected from the range of about 300° F. to about 1000° F. and holding the pressed product at the first temperature for a period selected from the range of about 1 hour to about 38 hours; heating the pressed product under vacuum at a rate of about 20° F. to about 120° F. from the first temperature to a second temperature selected from the range of about 1500° F. to about 2800° F. and holding the pressed product at the second temperature for a period selected from the range of about 1 hour to about 38 hours; heating the pressed product under vacuum at a rate of about 20° F. to about 120° F. from the second temperature to a third temperature selected from the range of about 3000° F. to about 4000° F. and holding the pressed product at the third temperature for a period selected from the range of about 1 hour to about 38 hours; allowing the pressed product to cool to room temperature; and machining the pressed product to a desired size, thereby forming the sputtering-target plate that is sputterable to form highly uniform, low-resistivity films of the refractory metal, the sputtering-target plate having a density greater than 97% of a theoretical density of the refractory metal. ### Claim 2 (depends on 1) The method of claim 1, further comprising bonding the sputtering-target plate to a backing plate. ### Claim 3 (depends on 1) The method of claim 1, wherein the powder has a Fischer sub-sieve size of from about 2 to about 5 microns as measured according to ASTM B-30-65. ### Claim 4 (depends on 1) The method of claim 1, wherein cold isostatically pressing the powder comprises holding the powder at pressure for a period of about 5 minutes to about 30 minutes. ### Claim 5 (depends on 1) The method of claim 1, wherein cold isostatically pressing the powder comprises holding the powder at pressure for a period of about 7 minutes to about 20 minutes. ### Claim 6 (depends on 1) The method of claim 1, wherein (i) the first temperature is selected from the range of about 400° F. to about 700° F., (ii) heating to the first temperature comprises heating at a rate of about 70° F. to about 100° F., and (iii) the pressed product is held at the first temperature for a period selected from the range of about 4 hours to about 12 hours. ### Claim 7 (depends on 1) The method of claim 1, wherein (i) the second temperature is selected from the range of about 1700° F. to about 2200° F., (ii) heating to the second temperature comprises heating at a rate of about 40° F. to about 60° F., and (iii) the pressed product is held at the second temperature for a period selected from the range of about 10 hours to about 22 hours. ### Claim 8 (depends on 1) The method of claim 1, wherein (i) the third temperature is selected from the range of about 3200° F. to about 3600° F., (ii) heating to the third temperature comprises heating at a rate of about 25° F. to about 40° F., and (iii) the pressed product is held at the third temperature for a period selected from the range of about 10 hours to about 24 hours. ### Claim 9 (depends on 1) The method of claim 1, further comprising, after machining the pressed product, cleaning the machined pressed product and, thereafter, rinsing the machined pressed product.