A level conversion circuit has a keeper circuit for retaining an intermediate output node at a high output level to avoid it floating due to leakage through a pullup transistor in a shifting circuit. Many embodiments include multi-buffering logic for implementing a procedure for a processing unit of a specialized processing element. After a first electroless plating layer and a first conductive material are sequentially grown on a surface of the first base film, a first coating conductive layer composed of the first electroless plating layer, the first conductive material and the first surface conductive layer, is etched to have a reduced thickness.