64‐1: Protrusion‐free LTPS Using the CMP Process and Its OLED Application

Low Temperature Polysilicon (LTPS) is the most popular channel material used in the thin film transistor and it has the protrusions due to the volume expansion of Si and the presence of its native oxide. The protrusions cause the negative effects such as interface trap, hysteresis and so on. In that sense, the heights need to be lowered or eventually flattened. In this study, we used the chemical mechanical planarization (CMP) technique to reduce the surface roughness of LTPS to the 1nm and even lower. One of the most difficult problmes in the large sized CMP process is the removal of slurry residues after CMP and we successfully overcome the issue by using the hydrophilic angent. Finally, we are succesfully able to prepare AMOLED panel with reduced gate insulator thickness by using the CMP process and it shows less hysteresis results.