ABSTRACT
Since the 1990s, optical profilers based on interference microscopy techniques are the most widely used characterization tools for fast and high-resolution three-dimensional topography measurements of micromachined surfaces and of free-standing microstructures. They are also used for a long time, but in a lesser extent, for out-of-plane vibration mode shapes measurements of microstructures and are emerging in the biomedical field. In this chapter, besides providing the basics of monochromatic and low-coherence interference microscopy, we intend to provide an up-to-date and fairly comprehensive review of optical configurations, performances, and applications of interference microscopy techniques in static and dynamic modes of operation for fabrication process control and for microelectromechanical systems (MEMS) characterization. An emphasis was put on the practical issues found when measuring real microstructures and on the analysis of less-known measurement capabilities such as spectral reflectance and film thickness mapping, hermeticity testing of wafer-level vacuum packaging, and vibration measurements by time-averaged and stroboscopic interference microscopy. The chapter is supplemented by a large set of carefully selected references for further reading. The numerous interferogram processing techniques developed since the 1970s are not covered in this chapter, but a suitable bibliography is given for readers interested in this topic.
