Spectrally-resolved white-light interferometry, reflectometry

 Multilayer circuits consisted of a stack of transparent conductive thin-film layers have been widely applied as the core and high-tech components throughout entire industries including semiconductor, flat panel display, and LED industries. In the semiconductor industry, the development of a stacked package technology leads to a new paradigm for manufacturing process by providing a volumetric packaging solution for higher integration and performance, and new products with 3D packaging technology meets the needs of more diverse and complex consumers. There are increasing demands for inspection of the internal structure of multilayer films. In the display industry, an organic luminescent electronic display (OLED) with multilayer transparent electrodes has emerged as the new generation display technique to provide superior mechanical flexibility, electrical conductivity, and optical transparency. It requires field inspection solutions in order to improve productivity. In photovoltaic cells and LED lamps, which are attracting attention as clean energy source, the metrology of thin film structure is also required to control the manufacturing process. However, there still remain many technical limitations to overcome for measurement of the internal structure of the sample without damage. For these reasons, our group has focused to develop a new optical technique that goes one step further than conventional methods. Recently, our research team has developed an innovative Linnik interferometric configuration based on spectrally-resolved white-light interferometry, which provides simultaneous measurements of the top surface and its underlying film surfaces in a multilayer film structure without any damage to the sample. In the near future, our team will provide a general metrological tool for 3D inspection of multilayer film structure in thin-film metrology.