Critical invisible defect detection system of thin film transistor panels using Kelvin probe force microscopy

[Display omitted] •The TFT panel is fabricated to conduct an experiment for detection of the most critical invisible defects.•The proposed KPFM-based method allowed the simultaneous measurement of topography and CPD of the pixels without any damages.•By applying the method, inactive pixels can be clearly distinguished from the active pixels by single line scan. In this paper, a novel method that can perform measurements of the contact potential difference (CPD) between a tip and a thin film transistor (TFT) panel using the Kelvin probe force microscopy (KPFM) is proposed for inspection of critical invisible defects on TFT panels. In this application, the surface potential of a TFT panel is inferred from the electrostatic interaction force between a tip and a TFT panel induced by the electric field. The experimental results are given to illustrate that the KPFM provides a novel and feasible way to detect the most critical invisible defects on TFT panels.