Copper & Brass FeCl₃

Chemical Etching Formula
QAl9-2 Aluminum Bronze with FeCl₃

Working with QAl9-2 Aluminum Bronze on a chemical etch line begins with the right formula. The FeCl₃ system documented below produces through etch (double-sided) across 0.05-0.3 mm sheet, with a minimum hole-diameter range of 60-360 μm and a minimum line-width range of 100-300 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
42 °Bé Concentration
1.390 Specific Gravity
48 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.05-0.3 mm Thickness Range
0.15 mm Typical Thickness
0.21-2.64 m/min Conveyor Speed Range
0.69 m/min Typical Speed
60-360 μm Min Hole Ø Range
100-300 μm Min Line Width Range
9-57 μm Undercut Range
2.65 Etch Factor (EF)
97.4% Typical Yield (97-97.7%)

Why FeCl₃ for QAl9-2 Aluminum Bronze?

On QAl9-2 Aluminum Bronze, 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 QAl9-2 Aluminum Bronze etch line runs a variant of this formula.

Process Window & Bath Control

The process window for this FeCl₃ formula centres on 48°C and 42 °Bé. Conveyor speed spans 0.21-2.64 m/min over the 0.05-0.3 mm thickness band; the typical operating point is 0.69 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

When laying out artwork for QAl9-2 Aluminum Bronze at through etch (double-sided), plan for a minimum hole diameter in the 60-360 μm range and a minimum line width in the 100-300 μm range, depending on the chosen sheet thickness within 0.05-0.3 mm. The etch factor of ~2.65 and undercut range of 9-57 μm determine how much the mask must be biased to land the finished dimension on target.

Design Rule Summary
• Minimum hole diameter range: 60-360 μm
• Minimum line width range: 100-300 μm
• Single-side undercut range: 9-57 μm
• Typical etch factor (EF): 2.65

Yield & Production Economics

Typical mass-production yield for QAl9-2 Aluminum Bronze in the FeCl₃ system is 97.4%, within an observed range of 97-97.7%. 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

Parts produced with the FeCl₃ formula on QAl9-2 Aluminum Bronze are common in lead frames, busbars, flexible heater elements, RF gaskets, and precision electrical contacts. The burr-free, stress-free nature of chemical etching makes it the preferred process wherever flatness and edge quality matter more than raw throughput.

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

Frequently Asked Questions

Single-side undercut ranges 9-57 μm depending on thickness and dwell time. When sizing the photomask for a finished feature on QAl9-2 Aluminum Bronze, subtract twice the expected undercut from the target width so the etched dimension lands on specification.

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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