Johnson Matthey Electronics, Inc.

Cominco, Ltd.

Comino Ltd.

Cominco Electronic Materials Inc.

John Alden Dunlop

Janine K Kardokus

Roger Alan Emigh

Robert W Smyth

Gerald W Toop

Jun Yuan

Edward Francis Milner

Hans Rensing

A sputtering target comprising a body of metal such as aluminum and its alloy with an ultrafine grain size and small second phase. Also described is a method for making an ultra-fine grain sputtering target comprising melting, atomizing, and depositing atomized metal to form a workpiece, and fabricating the workpiece to form a sputtering target. A method is also disclosed that includes the steps of extruding a workpiece through a die having contiguous, transverse inlet and outlet channels of substantially identical cross section, and fabricating the extruded article into a sputtering target. The extrusion may be performed several times, producing grain size of still smaller size and controlled grain texture.

Sputtering target with ultra-fine, oriented grains and method of making

Lead with a low alpha particle emission is produced by selecting an orebody wherein lead mineral is present in a coarsely disseminated form and substantially free of impurities. The ore is selected from a host rock that is relatively low in alpha emitters, such as a carbonate rock. The ore is mined and is milled such that the lead mineral can be separated from the host rock and any other minerals. The ground ore may be screened into one or more fractions having a narrow range of particle sizes. Each fraction is formed into a fluid suspension, and each suspension is subjected to gravity separation to remove the host rock and any other minerals which substantially contain the alpha particle-emitting substances, and to recover the lead mineral as a concentrate with a low alpha count. The lead concentrate is subjected to a suitable reduction operation that may include a conversion of the concentrate into a reducible form, without the introduction of alpha emitters, for the recovery of a low alpha lead. When the lead mineral is galena, suitable reductions include the smelting with sodiuim carbonate with or without an oxygen-bearing gas and electrolytic reduction in a molten bath of lead chloride. The low alpha lead recovered from these operations has an alpha count of about 0.02 alpha particle per cm.sup.2 per hour or less, and the count does not substantially increase with time. The recovered low alpha lead may be further purified by electro-refining.

Method for making low alpha count lead

Lead with a low alpha particle emission is produced by selecting an orebody wherein lead mineral is present in a coarsely disseminated form and substantially free of impurities. The ore is selected from a host rock that is relatively low in alpha emitters, such as a carbonate rock. The ore is mined and is milled such that the lead mineral can be separated from the host rock and any other minerals. The ground ore may be screened into one or more fractions having a narrow range of particle sizes. Each fraction is formed into a fluid suspension, and each suspension is subjected to gravity separation to remove the host rock and any other minerals which substantially contain the alpha particle-emitting substances, and to recover the lead mineral as a concentrate with a low alpha count. The lead concentrate is subjected to a suitable reduction operation that may include a conversion of the concentrate into a reducible form, without the introduction of alpha emitters, for the recovery of a low alpha lead. When the lead mineral is galena, suitable reductions include the smelting with sodium carbonate with or without an oxygen-bearing gas and electrolytic reduction in a molten bath of lead chloride. The low alpha lead recovered from these operations has an alpha count of about 0.02 alpha particle per cm.sup.2 per hour or less, and the count does not substantially increase with time. The recovered low alpha lead may be further purified by electro-refining.

Tungsten-titanium sputtering targets with improved characteristics are made from high-purity tungsten powder and a second powder consisting of high-purity titanium hydride powder or high-purity titanium hydride powder and high-purity titanium powder. The second powder contains at least 5%, preferably 25% to 100% by weight of titanium hydride powder. A powder mixture having a binodal particle size distribution with respect to the tungsten and second powders is placed under a containment pressure in a die. The die is heated in a vacuum hot-press chamber to a temperature sufficient to dehydride the titanium hydride, and to remove gases and alkali metals. The die is then heated to a second temperature in the range of 1350.degree. to 1550.degree. C. while maintaining the containment pressure and vacuum. A compaction force in the range of 2000 to 5000 psi is then applied to form a compact. The compaction force and vacuum are subsequently released and the compact is cooled. The compact is easily machined to give a sputtering target having a density of at least 95%, preferably, at least 100% of theoretical density, a total gas content of less than 850 ppm, a carbon content of less than 100 ppm and low particulates upon sputtering.

Method for making tungsten-titanium sputtering targets and product

Lead with a low alpha particle emission is produced by selecting an orebody wherein lead mineral is present in a coarsely disseminated form and substantially free of impurities. The ore is selected from a host rock that is relatively low in alpha emitters, such as a carbonate rock. The ore is mined and is milled such that the lead mineral can be separated from the host rock and any other minerals. The ground ore may be screened into one or more fractions having a narrow range of particle sizes. Each fraction is formed into a fluid suspension, and each suspension is subjected to gravity separation to remove the host rock and any other minerals which substantially contain the alpha particle-emitting substances, and to recover the lead mineral as a concentrate with a low alpha count. The lead concentrate is subjected to a suitable smelting operation, without the introduction of alpha emitters for the recovery of a low alpha lead. When the lead mineral is galena, the smelting is preferaby carried out with sodium carbonate and an oxygen-bearing gas in the presence of sodium chloride as a fluxing agent to form a low melting point slag. The low alpha lead has an alpha count of about 0.02 alpha particles per cm.sup.2 per hour or less, and the count does not substantially increase with time.

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Veradale, WA, United States of America

John Alden Dunlop