Tungsten etchant

Tungsten etchant is a mixture of potassium hydroxide and potassium ferricyanide based solution that facilitates the removal of tungsten and other materials like aluminium by dipping the substrate into the etching solution.

Selective etchants for tungsten thin-film metallizations used in semiconductor and microelectronics technology. Etchants are buffered, mildly alkaline ferricyanide-based formulations providing high resolution patterns with minimal undercutting and photoresist compatibility. Etchant is ready to use (no dilution required). Controlled, uniform etching is achieved by immersion or spray etch technique. Etch Capacity (rate declines at ∼70%) of 64 g/gallon. Recommended Operating Temperatures: 20-80 °C (30-40 °C most common).

1. Select your etching method according to the table belowEtch Rate (Immersion) Etch Rate (Spray)

• 20°C = 30 Å/second
• 30°C = 140 Å/second 20°C = 80 Å/second
• 60°C = 250 Å/second

2. Rinse with DI water