As RoHS banned the usage of Lead (Pb), now the semiconductor industry is searching and researching for various alternatives to Tin/Lead (SnPb). They could find a lot of alternatives such as Matte Tin, Tin-Bismuth (SnBi), Tin-Copper (SnCu), Tin-Zinc (SnZn), Nickel-Palladium (NiPd), Nickel-Palladium-Gold (NiPdAu), Nickel-Palladium-silver (NiPdAg), Tin-Silver (SnAg), Tin-Indium (SnIn), Tin-Silver-Copper (SnAgCu), etc.

But until now, none of them is proved as true alternative to Tin-Lead (SnPb) in terms of quality, reliability, and cost.

Meanwhile Matte Tin (Sn) has become a popular alternative due to its low cost and huge availability to component manufacturers. In today’s competitive market, the component manufacturers also more interested in using Matte Tin because of its low cost.

The 232°C melting point matte Sn of 232°C fits well within the 230°C to 260°C heat-tolerance temperature of today’s components. In addition, matte Sn has very low toxicity and is easily controlled.
Matte Sn is a logical drop-in replacement available at this time. It is a plating finish that already has a history of reliability and successful manufacturing experience. The industry has always been driven to one standard in an effort to simplify the manufacturing strategy.

Numerous matte Sn-plating baths are commercially available on the market today. These are ready for use with Pb-free solder paste, providing for a totally Pb-free product. Matte Sn finish is universally compatible with all existing lead-alloy and Pb-free solders, pastes and printed wiring boards.

Tin whiskers are a potential concern with high-tin (Sn) content lead finishes (this includes alloys such as SnBi, and SnCu). Nowadays most of the components manufacturers are testing the components for the Tin whiskers using the NEMI/JEDEC/JEITA defined stress conditions and declares as “NO whiskers” if they don’t find any whisker longer than 50um after 3000 hours / 3000 cycles stress testing. You can go through that data for comparing with your screening requirements.

Based on ease of manufacture and performance, reverting back to pure matte Sn from a controlled plating process with the whisker mitigating anneal process is the most reliable and logical choice.

It should be noted that the components are in market with 100% matte Sn for many years, thus a knowledge and experience level already exists.