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US 7,090,763 B2Granted
Process for the production of shaped articles of niobium or tantalum by electrochemical etching
AssigneeH. C. Starck GmbH
InventorsMarianne Gottschling, Josua Löffelholz, Mathias Albert, Günter Sadowski
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Abstract
Process for the production of shaped articles of niobium or tantalum by electrochemical etching of a niobium or tantalum sheet covered by a structured photoresist mask in an aqueous solution containing hydrofluoric acid, the etching being effected under electrochemical conditions under which strong noise is superposed on the etching current and the etching solution contains a water-soluble polymer.
Claims7
A process for producing shaped articles comprising:
- etching electrochemically a sheet selected from the group consisting of niobium sheet and tantalum sheet, said sheet being covered by a structured photoresist mask, the etching being performed in the presence of an aqueous etching solution comprising,
- (i) hydrofluoric acid,
- (ii) a water-soluble polymer, and
- (iii) ammonium hydrogen fluoride in a concentration of from 10 to 100 g/l, wherein the etching is performed with a resulting etching current, and a noise is superposed on said resulting etching current, said noise having a mean variation of 5–10% relative to an absolute etching current.
1 more element
Dependencies are inferred from the claim text.