{HEAD ~ The circuit board} 1, wherein said {TAIL ~ halogen compound} is at least one compound selected from the group consisting of YF3, YOF, LaF3 and CaF2 
{ HEAD ~ The circuit board } 1 , wherein said { TAIL ~ halogen compound } is at least one compound selected from the group consisting of YF3 , YOF , LaF3 and CaF2
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH