Authors: Y. Zhang, Y-Z Zhang, D.C. Miller, J.A. Bertrand, R. Yang, M.L. Dunn, S.M. George, Y.C. Lee
Affilation: Invitrogen/Molecular Probes, United States
Pages: 932 - 935
Keywords: fluorescecne tag defect defect inspection ALD film
Barrier coatings are essential to protect organic light emitting diodes (OLED) as well as polymer packaged components from moisture- and oxygen-aided deteriorization. One such coating technology is atomic layer deposition (ALD), used here to grow a nano-thickness alumina layer upon a polymer substrate. This coating’s moisture transmission rate can be lower than 0.0001 gm/m2/day, which is 10,000X better than that of a typical polymer. Such improvement may enable the use of polymer substrates for application in flexible displays in addition to the hermetic sealing of polymer packages. Defects, which may arise during processing or subsequent handling, allow the leakage of damaging reactive species. Therefore, to implement the ALD-based barrier coating process in manufacturing, two key issues must first be addressed: quality control and reliability. Coating-related defects have to be inspected and controlled in real time to assure high-yield manufacturing. In addition, coating configurations have to be designed to avoid crack initiation under various thermal-mechanical loadings. To support these two activities, we have developed novel fluorescecent tags to visualize micron/submicron-level defects and/or cracks. The fluorescent tags can be excited by commonly used excitation sources and yield a bright fluorescence signal. In addition, the tags have particularly designed lipophilic moiety enabling selective binding to the sites of defects or cracks about specific materials based on the difference of physical properties such as hydrophobicity of the coating surface.