Formation of a constricted portion in an interconnect pattern is inhibited while moderating design rule for a phase shifting mask. When an interconnect pattern including a plurality of straight lines that are arranged in parallel is formed in a photoresist film on or over a wafer, the process thereof comprises: providing different phase apertures 114 and 116 in longitudinal external side of the interconnect apertures 110 and 112 in the phase shifting mask 100, the different phase aperture providing a phase of light that is different from a phase of light through the interconnect apertures 110 and 112; transferring a basic pattern in the photoresist film via an exposure by using the phase shifting mask 100, the basic pattern containing the interconnect pattern and a temporary pattern formed from an end of the interconnect pattern toward a longitudinal external side thereof; and transferring a temporary pattern in the photoresist for removing the temporary pattern from the basic pattern via an exposure by using a trim mask.