| abstract |
Elemental fluorine is often manufactured electrochemically from a solution of KF in hydrogen fluoride and contains varying amounts of entrained electrolyte salt in solid form as impurity. The invention concerns a process for the purification of such impure elemental fluorine by contact with liquid hydrogen fluoride, e.g. in a jet gas scrubber or by bubbling the raw fluorine through liquid hydrogen fluoride. After this purification step, any entrained hydrogen fluoride is removed by adsorption, condensing it out or both. After passing through a filter with very small pores, the purified fluorine is especially suited for the semiconductor industry as etching gas or as chamber cleaning gas in the manufacture of semiconductors, TFTs and solar cells, or for the manufacture of micro-electromechanical systems ("MEMS"). |