Metal-etching process
AssigneeAmerican Etching & Manufacturing
InventorSai K. Lee
Life of this patent
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Abstract
An improved metal etching process including preparation of a metal substrate, developing a photoresist on the substrate, coating the exposed substrate with electroless phosphorous nickel alloy, removing the developed photoresist and etching the then exposed substrate. The preparation for depositing the electroless nickel includes washing the surface of the substrate with a very dilute acidic ferric chloride solution, immersing the substrate in a hydrochloric acid solution, and applying a thin metal layer by electrolytic plating, seriatim.
Claims22
A method of etching portions of a metallic substrate, comprising the steps of
- plating a first thin layer of metal onto the substrate;
- coating the portions of the plated substrate to be etched with a temporary mask;
- applying a second thin layer of metal onto the uncoated portions of the once plated and coated substrate and plating over this second layer with a third layer comprising phosphorous rich electroless nickel;
- stripping the temporary mask;
- and
- etching through the portions of the plated substrate uncovered by removal of the temporary mask sufficiently to etch through the substrate.
A method for etching portions of a metallic substrate, comprising in sequence the steps of:
- applying a first thin layer of electrolytic nickel to the substrate;
- applying a thin coating of photoresist material on the first thin layer of electrolytic nickel on the substrate;
- applying a photomask over the coated substrate, leaving a portion of the coated substrate exposed to radiation penetrating through the photomask;
- hardening the unmasked photoresist material by radiation;
- developing the photoresist material;
- applying a second thin layer of electrolytic nickel to the first thin layer of electrolytic nickel exposed on the substrate;
- plating the second thin layer with phosphorous rich electroless nickel;
- stripping the developed photoresist material;
- and
- etching the portion of the plated substrate uncovered by removal of the photoresist material sufficiently to etch through the substrate.
Dependencies are inferred from the claim text.