Copper is widely used in precision industries due to its outstanding electrical conductivity, superior thermal transfer capability and good ductility. Copper etching, or photochemical etching of copper, is a subtractive manufacturing technique that fabricates custom thin copper parts by selectively dissolving unmasked copper material with controlled chemical etchants. Unlike stamping, laser cutting or CNC machining, photochemical etching imposes no mechanical force or thermal damage to copper workpieces, maintaining its native high conductivity and ductility without introducing residual stress or edge burrs.

Process Workflow

1. Material preparation: Select pure copper or copper alloy sheet/foil (C1100, C1020 oxygen-free copper). Ultrasonic degreasing and micro-etching remove surface oil, oxides and contaminants to secure photoresist adhesion.
2. Dry film lamination: Hot-roll laminate photoresist onto both sides of cleaned copper substrate under cleanroom conditions.
3. UV exposure & development: Double-sided alignment and UV exposure transfer custom patterns onto photoresist. Un-exposed resist is washed away to expose bare copper areas. Half-etching is available for partial thickness reduction.
4. Copper chemical etching: Workpiece passes through spray etching line. Customized etchant selectively dissolves exposed copper. Etchant temperature, concentration, spray pressure and conveyor speed are precisely regulated to guarantee uniform etch rate.
5. Stripping and cleaning: Strip remaining cured photoresist, neutralize and rinse thoroughly with DI water to remove residual etchant.
6. Post-treatment & inspection: Surface finishing, optional plating or anti-tarnish passivation. Dimensional metrology and visual inspection verify critical dimension, flatness and edge quality.

Core Advantages

• Preserve electrical & thermal performance: No mechanical stress or heat damage, fully retains copper’s high conductivity and thermal conductivity, critical for thermal and RF components.
• Burr-free smooth edges: Eliminates secondary deburring, ideal for high-frequency electrical contacts and heat transfer structures.
• Ultra-fine complex patterns: Process ultra-thin copper foil down to 0.01mm, manufacture dense micro-hole arrays, narrow slots, intricate outlines and half-etched recessed features.
• Low-cost prototyping: Design updates only require new phototool, no expensive hard stamping dies, greatly shortens sample lead time for R&D.
• High batch consistency: Stable dimensional accuracy in mass production, uniform feature size across large copper sheets.

Application Fields

• Thermal management: Vapor chamber micro channels, heat spreaders, copper heat sink foils.
• Electronics & RF: EMI shielding parts, RF antenna foils, flexible contact terminals, PCB internal copper structures.
• Semiconductor packaging: Copper lead frames, micro interconnects, package heat dissipation components.
• New energy: Fuel cell flow field structures, battery conductive busbars and thin current collectors.
• Medical & optical: Micro copper sieves, optical aperture masks and precision conductive shims.

Design & Process Considerations

• Copper has a fast etching rate; tighter parameter control is required compared with stainless steel to avoid over-etching.
• Design guideline: Minimum hole/slot width ≥1.2 × copper material thickness for stable etching results.
• Oxygen-free copper etches differently from regular C1100 copper; material grade must be specified upfront.
• Copper is prone to oxidation and tarnishing. Anti-tarnish passivation or nickel/gold plating is recommended for long-term reliability.
• Thin copper foils are soft and prone to wrinkling; specialized fixtures are needed during etching and handling.