Patent ID: 7727784

Claim:
A fabrication method of a display device which forms a first thin film transistor which is formed in a first region and has a first threshold value, and a second thin film transistor which is formed in a second region and has a second threshold value which differs from the first threshold value, the fabrication method comprising: a semiconductor film forming step which forms a semiconductor film; a first impurity implanting step for implanting first impurities for a threshold value control in the semiconductor film which is formed in the first region and the second region; a first crystallizing step for performing the crystallization of the semiconductor film and the activation of the first impurities in the first region and the second region by applying heat treatment to the semiconductor film in the first region and the second region; a second impurity implanting step for implanting second impurities for a threshold value control in the semiconductor film in the first region and the second region after the first crystallizing step; and a second crystallizing step for performing the crystallization of the semiconductor film of the second region and the activation of the second impurities by applying heat treatment only to the semiconductor film in the second region out of the semiconductor films in the first region and the second region.