The invention is directed to techniques for communicating messages between windows or frames in a computer display. The phase and frequency of the input reference signal can be determined automatically by the phase lock loop, and the output synchronization signal can be generated such that the frequency and the phase of the output synchronization signal are identical to those of the input reference signal. An oxygen barrier conductive film is formed on the interlayer insulating film and being inclusive of an area of the conductive plug as viewed in plan. With the change of sub array shape pattern in accordance with a beam scanning direction, the group shape pattern of each group also changes.