The photoinduced phase formation in a strongly correlated crystal (EDO-TTF)2PF6 (EDO-TTF: 4,5-ethylenedioxytetrathiafulvalene) is investigated using a 12 fs laser pulse. The formation time is determined as 40 fs with observation of coherence of electron-phonon coupled excited states prior to formation. The temperature-independent dephasing time is determined as 竏シ22 fs up to 180 K and the frequency of phonon oscillation is 竏シ38 THz, corresponding to the intramolecular vibrations in EDO-TTF. The phase formation is coherently controlled by relative-phase-controlled two-pulse excitation.