Lead-free flux : There is no lead-free flux without halogen. Under the requirement of lead-free, only bromate, bromide and organic acid as the structure of synthesis. The representing ones are 92FT KP-15 Paste Flux : Basically paste flux is structured in Solder Paste Flux and is specially made for BGA applications. The lead containing paste flux is represented by K-37 and lead free is K-41