Immersion-Specific Defects of High-Receding-Angle Topcoat

Abstract

Dynamic receding contact angle (RCA) is a well-known parameter for estimating the degree of immersion-specific defects that have mainly circular and bridge shapes. In general, these defects decrease in number with increasing RCA of the topcoat (TC). However, we found the occurrence of circular defects despite using the TC with a large RCA. In this study, we analyzed the relationship between the physical properties of TC to reduce the number of defects. The result shows that the number of defects depends not only on a large RCA but also on a small amount of water uptake of TC. To understand well the degree of defects, the effective hysteresis (EH) is defined in terms of the RCA, the advancing contact angle (ACA) and the water absorption of TC. EH will be a useful way of explaining the circular defects. The characteristics of the defects are also discussed with a focus on the structure of the polymer attached to water.