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US 7,740,723 B2Granted
Controlled-grain-precious metal sputter targets
AssigneePraxair S.T. Technology, Inc.
InventorsAndrew C. Perry, Paul S. Gilman, Wendell Stuber, Binu Mathew
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Abstract
A precious metal sputter target has a composition selected from the group consisting of platinum, palladium, rhodium, iridium, ruthenium, osmium and single-phase alloys thereof. The sputter target's grain structure is at least about 99 percent recrystallized and has a grain size of less than about 200 μm for improving sputter uniformity. The cryogenic method for producing these sputter targets is also effective for improving sputter performance for silver an gold sputter targets.
Claims7
A method of forming sputter targets comprising the steps of:
- a) cooling a target blank to a temperature of less than about −50° C., the target blank having grains having an initial grain size and a composition selected from the group consisting of platinum, palladium, rhodium, iridium, ruthenium, osmium, silver, gold and single-phase alloys thereof;
- b) deforming the cooled target blank to introduce strain into the target blank and to form a deformed grain structure;
- c) recrystallizing the deformed grain structure to form a target blank having recrystallized grains, the target blank having at least about 99 percent recrystallized grains and the recrystallized grains having a fine grain size smaller than the initial grain size;
- and
- d) finishing the target blank to form a finished sputter target at a low temperature sufficient to maintain the fine grain size of the finished sputter target at less than about 200 μm and a face centered rain orientation in the (111), (200), (220) and (311) directions for improving sputter uniformity, the sputter target has a grain orientation ratio of at least about 10 percent each of the (111), (200), (220) and (311).
2 more elements
Dependencies are inferred from the claim text.