Study on One Infrequent Influencing Factor of TFT-LCD Life

摘要

Through a lot of analysis and test on a rare failure (ongoing black mura), we found that the distance of TFT U shaped channel to the gate line edge have great influence on the stability of TFT device. When the distance is less than a critical value, the characterization of TFTs would degrade after a long-time of stress or aging, lead to decrease of Ion and increase of Vth, resulting in poor life time of TFT-LCD for the abnormal black phenomenon. By BTPS (Bias, Temperature, Photo, Stress) [1-2] and aging test, we compare the stability of TFTs with different distance value, establish calculation model and design spec. Effective improvement have achieved by process adjusting and design changes.