By utilizing flat display panel manufacturing equipment and innovative techniques, we have successfully developed short channel Top‐gate amorphous InGaZnO4 thin‐film transistors (TG a‐IGZO TFTs) at Gen4.5. Despite the challenge of facing issues with the lateral diffusion of hydrogen during process and short channel effects, we managed to optimize the uniformity and drain‐induced barrier lowering with the novel structure of TFTs. After optimizing the device structure, we have achieved short channel TFTs with channel length of 1.3um, Vth of ‐ 0.03V, mobility of 9.77 cm2 /Vs, and DIBL of 29mV/V, and successfully make a demo of 7.1inch miniLED with the ultra short channel TFTs.