White tin is a modified immersion process whereby an organic solderability preservative (OSP) is deposited onto bare copper and is then covered by a very thin layer (30 ~ 40 microinches) of Dextcoat FST flat solderable tin (Sn100).
More Details:
Tin Plating Thickness:
30 to 40 microinches
0.75 to 1.0 µm
Co-planarity
A major advantage of white-tin (versus HASL) is it's absolulte co-planarity features similar to that of gold plating.
More about the Process:
The OSP process provides a barrier to the copper/tin intermetalic as well as preventing oxidation and dendritc growth.
During the plating process, the bare copper is pre-treated with a tin acid cleaner at 120°F (48°C) followed by rinsing at ambient temperatures and then the copper is micro-etched at 80°F (27°C) and rinsed again before going through a flooded tin deposition at 150°F (65°C)
Recommended Handling:
Wear Gloves:
For safe handling, users must wear gloves prior to assembly to avoid oils and finger prints as much as poossible.
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