Often a deep analysis of inner structures, e.g. of a solder joint, is only possible by destructive preparation of the specimen and so uncovering the region of interest to make it accessible to other measurement and analysis methods.
A target preparation, which means the uncovering of a specific section of the specimen, needs a preferable exact knowledge, where in the specimen’s volume the defect etc. might be located. Non-destructive methods like X-ray or acoustic microscopy can help to gather such information.
Then a specific “preparation recipe” containing separation, grinding and polishing steps is necessary, which is the more complex, the more inhomogeneous the inner structure of the specimen is.
After successful preparation, the cross-section can be investigated using optical microscopy. Better details resolution and additional measurement and analysis options are possible using a Scanning Electron Microscope.