Copper Chemical Etching — Engineering Reference
Wet chemical etching of Copper is a precision subtractive process that defines fine features by selectively dissolving the metal through a photoresist-patterned mask. On Copper specifically, the etchant choice, bath temperature, and conveyor speed combine to set the etch factor, undercut, and yield envelope every production run lives in.
Why Wet Chemical Etching for Copper?
Compared to laser, stamping, or wire EDM, wet chemical etching imparts no mechanical or thermal load to Copper. The process is parallel — every feature on a sheet etches simultaneously — so feature count has no impact on tooling cost. For Copper parts with hundreds or thousands of micro-features per piece, that is the dominant economic argument.
- Burr-free, stress-free edges — no post-deburring on Copper required.
- Tooling cost flat with feature complexity — only the photomask changes.
- Fast prototype iteration — artwork edits, not tool re-cuts.
- Tight tolerance on thin gauge Copper (down to ±25 μm in production).
- Compatible with downstream passivation, plating, electropolishing.
Process Window for Copper
Production lines etching Copper run a closed-loop temperature band of typically ±1.5 °C, with bath specific gravity monitored each shift via hydrometer or refractometer. Conveyor speed inversely tracks sheet thickness: thinner stock runs faster, thicker stock slower, with the goal of holding etch factor (EF) above 2.5 and single-side undercut below thirty microns wherever possible. For Copper, the recommended chemistry is FeCl₃ at 38–42 °Bé.
| Recommended etchant | FeCl₃ at 38–42 °Bé |
|---|---|
| Bath temperature window | 40 – 55 °C (chemistry-dependent) |
| Specific gravity setpoint | 1.30 – 1.45 g/cm³ for ferric chloride systems |
| Conveyor speed range | 0.4 – 8.0 m/min (thickness-dependent) |
| Typical etch factor (EF) | 2.5 – 3.0 |
| Single-side undercut | 5 – 40 μm depending on depth and thickness |
| Minimum hole diameter | ≈ 1.2× sheet thickness |
| Minimum line width | ≈ 1.0× sheet thickness |
| Mass-production yield | 95 – 99% on mature recipes for Copper |
Common Applications for Chemically Etched Copper
Across the markets we serve, chemically etched Copper is most often deployed in filtration meshes, lead frames and connector blanks, surgical and consumer blades, EMI shielding gaskets, heat-dissipation vents, and decorative architectural pieces. Thickness and feature complexity push different applications onto different recipes.
Related Recipes & Process Parameters
Every formula and parameter row below is a live page on this site with the full chemistry, conveyor speed, and tolerance window for the exact material-thickness-etchant combination. These are the references our process engineers cite from on production shifts.
Related Material References
Related Production Applications
Related Process Equipment
Frequently Asked Questions
What is the minimum feature size on Copper?
As a working rule, the minimum hole diameter scales as 1.2× sheet thickness and minimum line width as ~1.0× thickness for Copper. At the fine end, photoresist resolution becomes the limiting factor — not the etchant.
What edge quality can I expect when etching Copper?
Wet chemical etching is non-contact, so etched Copper parts are completely burr-free, stress-free, and free of any heat-affected zone. Final edge cleanliness depends on photoresist adhesion and rinse cascade discipline.
How does temperature affect the etch rate on Copper?
Etch rate roughly doubles for every 10 °C of bath temperature increase. We operate Copper baths within ±1.5 °C of setpoint to keep undercut and etch factor in tolerance.
How is bath chemistry maintained over a production shift on Copper?
The FeCl₃ at 38–42 °Bé bath is titrated at shift start and replenished with concentrated stock + water based on specific-gravity drift. Spent bath is regenerated electrolytically where possible.
Frequently Asked Questions
What tolerances can you achieve for Wet Chemical Etching Copper?
Photochemical etching holds tight, repeatable tolerances on thin metal, which makes it well suited to Wet Chemical Etching Copper. Exact figures depend on material and thickness.
Can Wet Chemical Etching Copper be customised to my drawing?
Yes. Wet Chemical Etching Copper is made to order from your CAD/artwork, so dimensions, features and material are all tailored to your specification.
What is the typical lead time and minimum order for Wet Chemical Etching Copper?
Because etching needs no hard tooling, Wet Chemical Etching Copper can be prototyped quickly and scaled to volume. Share your drawing and quantity and we will advise lead time.