Copper & Brass FeCl₃

Chemical Etching Formula
C1100 T2 copper with FeCl₃

The FeCl₃ chemistry is a proven formula for C1100 T2 copper. This reference sheet lists the concentration (34 °Bé), specific gravity (1.320), bath temperature (44°C), and the full range of conveyor speeds and feature tolerances that result. Use it to size your process before committing to a production trial.

Formula Summary

The table below summarizes every parameter that defines this etching formula. Values listed as ranges scale with sheet thickness across the supported band.

FeCl₃ Etchant System
34 °Bé Concentration
1.320 Specific Gravity
44 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.01-0.02 mm Thickness Range
0.01 mm Typical Thickness
18.51-66.76 m/min Conveyor Speed Range
32.65 m/min Typical Speed
46252 μm Min Hole Ø Range
100 μm Min Line Width Range
46025 μm Undercut Range
2.88 Etch Factor (EF)
99.0% Typical Yield (99%)

Why FeCl₃ for C1100 T2 copper?

Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like C1100 T2 copper. The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on C1100 T2 copper is anisotropic etching with predictable undercut and an easily regenerated spent bath.

Process Window & Bath Control

The process window for this FeCl₃ formula centres on 44°C and 34 °Bé. Conveyor speed spans 18.51-66.76 m/min over the 0.01-0.02 mm thickness band; the typical operating point is 32.65 m/min. Every 5°C drop in bath temperature requires roughly a 30% reduction in conveyor speed to hold the same etch depth, so temperature stability is the single biggest lever on consistency.

Design Rules & Tolerances

Design rules for this recipe: hole diameter 46252 μm, line width 100 μm, single-side undercut 46025 μm — all as a function of thickness across 0.01-0.02 mm. The higher the etch factor (this formula holds about 2.88), the tighter the achievable tolerance. Below the minimum feature sizes, yield falls off steeply, so treat those numbers as hard floors rather than targets.

Design Rule Summary
• Minimum hole diameter range: 46252 μm
• Minimum line width range: 100 μm
• Single-side undercut range: 46025 μm
• Typical etch factor (EF): 2.88

Yield & Production Economics

Typical mass-production yield for C1100 T2 copper in the FeCl₃ system is 99.0%, within an observed range of 99%. The dominant yield-loss modes are photoresist pinhole defects and rinse-water contamination. Improving incoming sheet quality and photoresist coating consistency gives the highest yield-improvement leverage for this formula.

Typical Applications

Typical applications for C1100 T2 copper processed with FeCl₃ include lead frames, busbars, flexible heater elements, RF gaskets, and precision electrical contacts. The formula's tolerance band and yield make it well suited to medium-to-high-volume precision flat parts.

More Copper & Brass Formulas

Other formulas in the same material family.

C1020 OF Copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Half etch (single-sided) C1100 T2 copper FeCl₃ Half etch (single-sided)

Frequently Asked Questions

Spent FeCl₃ bath contains dissolved C1100 T2 copper ions and depleted oxidizer. Standard practice is chemical or electrolytic regeneration to recover activity, plus periodic decanting of metal-rich sludge for off-site recovery. Treatment to neutral pH with metals precipitation is the minimum before any discharge, and requirements vary by jurisdiction.

Need a Quote for This Process?

WET Etched runs production wet chemical etching lines using the FeCl₃ chemistry. Send us your part drawing and quantity for a full process quote.

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