We have developed a novel configuration of an X-ray grating interferometer for the phase imaging of a packaged IC chip. A square source grating is used, and a beam splitter and an analyzer grating are positioned downstream of the investigated sample. In the proposed method, the period of source grating is smaller than the last of two gratings, the configuration of which could be implemented for phase imaging. Phase images retrieved using the principle of in-line phase contrast imaging and phase detection are the phase stepping method used in the X-ray grating interferometer. The wrapped phase images of the packaged IC chip are obtained from nine Moiré fringe patterns, using an exposure time of 34ms for each scan.