Selective area polishing with depth resolution using a Dimpler

Dimple polishers have been used for many years to prepare thin samples for imaging in Transmission Electron Microscopy. However, the ability to selectively polish or remove a small area on a surface, combined with the controllable depth resolution, can find applications in other areas of metallography. In particular, semiconductor and MEMS devices contain complex structures of dissimilar materials buried in layers a few microns to a few nanometers in thickness and it is often necessary to gain access to such structures for development and failure analysis purposes. The ability to selectively polish down a particular area allows the structure of such features to be directly examined. The same holds for more traditional metallography applications, where precipitates, voids, and inclusions can be individually examined. Here, two case studies will be presented where we selectively examine a buried semiconductor structure and defects in electrodeposited copper with a serial-sectioning approach using a dimple polisher. Layer-by-layer removal allows reconstruction of the detailed structure of the buried features.