Immersion Silver Additive
CAS Number: 7761-88-8
Immersion silver additive is a complexant and anti-tarnish package for immersion silver PCB surface finish baths, depositing a thin 0.1–0.4 µm silver layer on copper pads via displacement plating. The anti-tarnish organic inclusion in the deposit prevents silver sulfidation and maintains solderability during storage. Immersion silver provides excellent electrical performance for high-frequency applications and is compatible with all soldering methods.
Technical Specifications
| pH | 4.0–5.5 |
| appearance | Clear, colorless to pale yellow liquid |
| operatingTemp | 40–55°C |
| silverContent | 2–5 g/L (as Ag⁺) |
| silverThickness | 0.1–0.4 µm |
| tarnishResistance | >6 months at 25°C/60%RH (with anti-tarnish) |
Applications
- High-frequency PCB surface finish (RF, microwave)
- Fine-pitch SMT and BGA pad finish
- Aluminum wire bonding PCB pad finish
- Press-fit and edge connector contacts
- LED and optical PCB reflective surface
Key Features
- Excellent high-frequency signal performance due to silver conductivity
- Anti-tarnish organic inclusion prevents sulfidation
- Flat, coplanar deposit for fine-pitch assembly
- Compatible with lead-free solder, aluminum wire bonding, and ACF