| Summary: | 碩士 === 元智大學 === 化學工程與材料科學學系 === 98 === ABSTRACT
Slot die coating is a pre-metered coating method frequently used in industries such as integrated circuit (IC), printed circuit board (PCB), color filter or antireflective material coating in LCD.
The aims of this study are two-fold, the construction of a three-dimensional computational fluid dynamics model (CFD model) of a slot die coater for photoresist by using the commercial CFD package-ANSYS FLUENT and the analysis of coating windows and defects. From simulation using this model coating defects such as air entrainment, break lines and dripping were all observed and analyzed.
The simulation involves three different sets of slot and coating gaps: (a) slot gap=100μm; coating gap=50μm, (b) slot gap=100μm; coating gap=30μm, (c) slot gap=50μm; coating gap=50μm. According to the results, reducing the coating gap can effectively reduce film thickness. Applying vacuum at the upstream can help stabilize the wet film and eliminate defects. Appropriate mass flow rate is needed for continuous film formation. A mass flow rate too low many lead to air entrainment defect. The fine film quality is dependent on stable coating bead, when the minimum dynamic contact angle of the moving substrate is greater than 155°, the wet films produced are prone to air entrainment or break line defects. Dripping occurs when the liquid mass flow rate is too high and the substrate velocity is too slow to carry away the liquid in time, or the substrate velocity is too high for the coating bead to form and formed accumulate in coating gap. Finally, the flow channel design is important for slot die coater and air should be completely removed from the channel so that it will influence the film quality.
Keywords: slot die coating, photoresist, computational fluid dynamics, theoretical modeling, coating window, Fluent.
|
|---|
