Chemical Etching Formula
W1 Pure Tungsten
with H₂O₂(30%)+NH₃(25%)
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.
Why H₂O₂(30%)+NH₃(25%) for W1 Pure Tungsten?
For W1 Pure Tungsten, H₂O₂(30%)+NH₃(25%) provides controllable, regenerable etching with predictable undercut. The chloride or acid species continuously break down the alloy's protective oxide while the oxidizer supplies the electrochemical driving force, producing clean, burr-free edges compatible with standard dry-film and liquid photoresists.
Process Window & Bath Control
Hold the bath at 58°C with concentration as specified (specific gravity 1.120). Across the 0.05-0.3 mm thickness range, conveyor speed runs from 0.12-0.98 m/min — thinner sheets move faster, thicker sheets slower, in roughly inverse proportion to thickness. A typical mid-range setpoint is 0.20 m/min for 0.15 mm stock. Use redundant PID temperature control to hold the bath within ±1.5°C, and titrate at least once per shift.
Design Rules & Tolerances
Design rules for this recipe: hole diameter 60-360 μm, line width 100-300 μm, single-side undercut 11-65 μm — all as a function of thickness across 0.05-0.3 mm. The higher the etch factor (this formula holds about 2.30), the tighter the achievable tolerance. Below the minimum feature sizes, yield falls off steeply, so treat those numbers as hard floors rather than targets.
• Minimum hole diameter range: 60-360 μm
• Minimum line width range: 100-300 μm
• Single-side undercut range: 11-65 μm
• Typical etch factor (EF): 2.30
Yield & Production Economics
Typical mass-production yield for W1 Pure Tungsten in the H₂O₂(30%)+NH₃(25%) system is 93.1%, within an observed range of 92.8-93.4%. 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 W1 Pure Tungsten processed with H₂O₂(30%)+NH₃(25%) include X-ray collimator grids, electron-beam apertures, and high-density precision masks. The formula's tolerance band and yield make it well suited to medium-to-high-volume precision flat parts.
More Tungsten Formulas
Other formulas in the same material family.
Frequently Asked Questions
Need a Quote for This Process?
WET Etched runs production wet chemical etching lines using the H₂O₂(30%)+NH₃(25%) chemistry. Send us your part drawing and quantity for a full process quote.