Surface treatment in PCB industry (I-Sn and Hard Gold)

5.Immersion Tin(I-Sn)

Due to all solders are based on tin, the tin coating can match any type of solder. The surface finish immersion tin can form a flat between copper and tin, this feature enables the sinter to have the same good weldability as the hot air leveling, without the headache of the unfitness in hot air leveling. The immersion Tin PCB cannot be stored for too long and must be assembled according to the production time.

Merits: Suitable for horizontal line production.Suitable for fine line processing, suitable for lead-free soldering, especially suitable for pressing technology.Very good flatness, suitable for SMT.

Demerits: Good storage conditions, preferably not more than 6 months, to avoid tin whisker.Not suitable for contact switch design. In the production process, the resistance welding film process requirements are high, otherwise, it will cause the soldering film to fall off. Nitrogen gas protection is needed for multiple welding. Electrical testing is also a problem.

6.Hard gold, in order to improve the wear-resisting property of the product and increase the lifetime that plating hard gold.