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US 6,150,279 AGranted
Reverse current gold etch
OwnerAmy Kuinventor
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Abstract
A method and apparatus for gold etching in semiconductor circuit manufacturing. An environmentally safe etching solution is used in an electroplating device to etch gold from a semiconductor substrate. The etching solution is free of iodine and cyanide based compounds and preferably includes thiourea.
Claims16
A method of etching gold from a surface of a substrate comprising the steps of:
- (a) holding an etchant bath in a container;
- (b) positioning the substrate and an anode in the etchant bath;
- (c) moving the substrate;
- (d) applying a sufficient amount of potential between the anode and the substrate to direct current flow from the substrate to the anode, to thereby etch gold from the substrate;
- and
- (e) collecting the etched gold at the anode.
3 more elements
A method of etching a gold layer from a substrate material comprising the steps of
- contacting said gold layer with an aqueous solution including thiourea and water, and
- passing a current through the substrate into the solution for a time sufficient to etch away said gold layer.
A method for etching patterns on a substrate having a gold layer comprising the steps of:
- providing a container containing a chemical bath for etching the substrate;
- placing the substrate in a holder adapted to receive the substrate for positioning and moving the substrate in the container;
- immersing an anode in the chemical bath for collecting gold to be etched from the substrate;
- immersing the substrate to be etched in the chemical bath;
- directing a current of gold ions from the substrate to the anode through the chemical bath;
- moving the substrate in the chemical bath until a substantial portion of the gold is etched away from the substrate;
- and
- collecting the etched gold on the anode.
5 more elements
Dependencies are inferred from the claim text.