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