A TG‐SA a‐IGZO TFT technology is demonstrated with a good V TH uniformity in the whole 14” OLED panel and a high reliability of +0.03V and −0.52V under PBTS and NBTIS, respectively. Mechanisms for device instability and the relative relationship between PBTS and NBTIS have been systematically analyzed. Finally, the prototype 14″ FHD OLED display with an excellent brightness uniformity using TG‐SA a‐IGZO TFTs backplane have been made successfully. Besides, the high reliability of devices have been confirmed through a longtime RA test without no obvious defects generated, which indicates excellent mass‐production prospect.