H01L2224/115

Separation of alpha emitting species from plating baths

A non alpha controlled plating bath including Tin species and a trace amount of Polonium species is utilized in a plating tool. The plating tool includes a Polonium filter element to remove Polonium species from the plating bath to selectively plate Tin upon a plating cathode. The filter may include a Titanium inner portion surrounding by a stannic oxide exterior. The filter may reduce the Polonium species by having the polonium absorb and then enter within the stannic oxide matrix. The filter may be located within the plating tool reservoir or filter housing. The filter may be fabricated by forming Tin upon a Titanium filter backbone and converting the Tin to stannic oxide.