Copper & Brass FeCl₃

Chemical Etching Formula
C1100 T2 copper with FeCl₃

Working with C1100 T2 copper on a chemical etch line begins with the right formula. The FeCl₃ system documented below produces through etch (double-sided) across 0.01-0.04 mm sheet, with a minimum hole-diameter range of 15-42 μm and a minimum line-width range of 100 μm. The numbers scale with thickness — thinner stock yields finer features.

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
36 °Bé Concentration
1.340 Specific Gravity
44 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.01-0.04 mm Thickness Range
0.02 mm Typical Thickness
5.44-24.33 m/min Conveyor Speed Range
11.25 m/min Typical Speed
15-42 μm Min Hole Ø Range
100 μm Min Line Width Range
46059 μm Undercut Range
2.85 Etch Factor (EF)
98.8% Typical Yield (98.8%)

Why FeCl₃ for C1100 T2 copper?

On C1100 T2 copper, the ferric chloride system attacks the alloy's oxide layer continuously while ferric ions drive dissolution. It is regenerable, compatible with standard photolithography, and produces clean burr-free edges — which is why nearly every C1100 T2 copper etch line runs a variant of this formula.

Process Window & Bath Control

The process window for this FeCl₃ formula centres on 44°C and 36 °Bé. Conveyor speed spans 5.44-24.33 m/min over the 0.01-0.04 mm thickness band; the typical operating point is 11.25 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

Feature sizes scale with sheet thickness. For this formula the minimum hole diameter ranges 15-42 μm and the minimum line width ranges 100 μm across the 0.01-0.04 mm band, following the industry 1.2× (hole) and 1.0× (line) thickness rules. Single-side undercut ranges 46059 μm, and the etch factor is about 2.85. Size your photomask by subtracting twice the expected undercut from each finished feature dimension.

Design Rule Summary
• Minimum hole diameter range: 15-42 μm
• Minimum line width range: 100 μm
• Single-side undercut range: 46059 μm
• Typical etch factor (EF): 2.85

Yield & Production Economics

Expect a yield in the 98.8% range for C1100 T2 copper with FeCl₃, with 98.8% typical on a well-controlled line. Most rejects trace back to upstream coating and exposure rather than to the etch bath itself, so tightening photolithography control is usually the fastest path to a higher number.

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

Standard pre-treatment is degrease, micro-etch to activate the surface, rinse, photoresist lamination or coating, UV exposure through the artwork, and develop. Pre-treatment quality directly drives yield for C1100 T2 copper: poor degreasing causes resist adhesion failures that show up as random pinhole defects in the etched pattern.

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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