Process and apparatus for etching copper masked by a nickel-gold mask
AssigneePSI Star
InventorNorvell J. Nelson
Life of this patent
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Abstract
Process and apparatus for anisotropically etching copper through a nickel-gold mask on a circuit board. An electrical connection is made between the copper and the reactor wall or another electrical conductor contacted by the etching solution. The copper is removed anisotropically, without undercutting or lateral etching of the copper beneath the nickel-gold mask.
Claims12
In a process for etching copper on a circuit board in the presence of another electrical conductor, the steps of:
- forming a metallic mask over portions of the copper to be retained, connecting the copper electrically to the other conductor, and contacting the exposed portions of the copper and the other conductor with a liquid etchant to effect removal of the copper.
In apparatus for removing copper from a circuit board in the presence of another electrical conductor, with a metallic mask covering portions of the copper to be retained:
- means for connecting the copper electrically to the other conductor to maintain the copper and the other conductor at substantially the same electrical potential, and means for contacting the exposed portions of the copper and the other conductor with a liquid etchant to effect removal of the copper.
In combination:
- a circuit board having a layer of electrically conductive copper on one side thereof, a nickel-gold mask covering portions of the copper, another electrical conductor in proximity to the circuit board, a liquid etchant contacting the exposed portions of the copper and the other conductor, and means connecting the copper and the other conductor electrically together to maintain the copper and the other conductor at substantially the same electrical potential.
Dependencies are inferred from the claim text.