Copper etching, also known as photochemical etching of copper, is a subtractive manufacturing process. It selectively removes unwanted material from thin copper sheets and foils using specially formulated etchants. Since there is no mechanical cutting force, the finished copper parts remain free of burrs and internal stress, which is ideal for thin, delicate copper structures.

How Copper Etching Works

1. Material Preparation: Degrease and clean copper sheet to eliminate oil, fingerprints and surface oxides for stable photoresist lamination.
2. Photoresist Lamination: Laminate dry photoresist film on both sides of the copper substrate.
3. UV Exposure: Align custom CAD phototool and expose under UV light. The resist on areas that need to be preserved will cure and harden.
4. Development: Rinse away unexposed photoresist to expose the copper regions ready for etching.
5. Chemical Etching: Immerse the workpiece in copper etching solution. Exposed copper dissolves uniformly while protected areas stay intact.
6. Stripping: Strip off the hardened photoresist film from the copper surface.
7. Final Inspection & Packaging: Dimensional metrology, surface quality inspection and cleaning before shipment.

Core Advantages of Copper Etching

• Burr-free and stress-free: No mechanical stamping or cutting, preventing deformation and material distortion for ultra-thin copper foil.
• Excellent precision for micro features: Produces fine slots, tiny holes and complex geometries. Minimum feature size can be close to copper sheet thickness.
• No expensive hard tooling: Digital phototool only, low prototyping cost and fast turnaround for small and medium batches.
• Great thermal & electrical retention: The etching process will not alter copper’s inherent high thermal conductivity and electrical conductivity.
• Easy design iteration: Adjust CAD patterns quickly without high tool rework charges.

Typical Application Fields

• Heat spreaders, vapor chamber internal wick structures and thermal conductive copper components
• EMI/RFI shielding gaskets, shielding frames for electronic devices
• Battery tabs, current collectors and conductive busbars
• Precision electrical contacts, flexible copper leads and lead frames
• Fine copper mesh, filter screens and decorative copper nameplates

Design Considerations for Copper Etching

• Copper etches much faster than stainless steel or nickel; bath temperature, concentration and spray pressure require tight control to avoid over-etching.
• Follow the general rule: the minimum feature width should not be less than the copper material thickness.
• Copper is prone to oxidation and tarnishing. Post treatments such as passivation, tin plating or nickel plating can be added upon request.
• Material grades differ: oxygen-free copper, C110 copper, copper alloys require slight adjustments to etching chemistry. Confirm copper grade before production.