Simulation of thin film thickness distribution for thermal evaporation process using a scanning linear source

Abstract

Thermal evaporation process is the main process involved in the production of OLED displays and with the trends toward larger substrate size and display resolution, film thickness uniformity must be carefully controlled in order to implement exact pixel data. To secure stable film thickness uniformity on the substrate area, thin films are deposited on large-area glass substrates via thermal evaporation process using a linear source. We designed a linear source and mathematical model was developed to describe the system with a focus on the linear source. Then, system parameters were determined to guarantee uniform thickness using computer-based simulation, replacing wasteful actual experiments, followed by carrying out experiments based on the determined parameters. After the deposition process, data from the mathematical model and experiments was compared and the resulting agreement was good, verifying the validity of the proposed method. Consequently, by applying the proposed method, display manufacturing process related to thermal evaporation can be controlled within a tight tolerance in order to maximize the production yield rate.