Circuit failure identification using focused ion beam and transmission electron microscopy characterisation techniques.

In this paper we present the development and improvement of techniques used in CNET Meylan during the last few years for localisation, cross sectionin g and observation of circuit failure using focused ion beam, scanning and t ransmission electron microscopy techniques. Failure analysis examples are g iven to illustrate the methods used. Defect localisation is carried out usi ng potential contrast and electrical testing. The imaging and ion milling c apability of the focused ion beam technique is used for cross sectioning th e failure area with an accurate control of the localisation. The physical o bservation of defects on the cross section is carried out either in situ us ing scanning ion microscopy or ex situ using electron beams. For higher res olution the defective area is ion milled using the focused ion beam techniq ue to produce a thin lamella containing the defect which can be then observ ed with sub-nanometer spatial resolution using transmission electron micros copy. Chemical analysis can also be carried out in the transmission electro n microscope using electron energy loss spectroscopy and electron energy fi ltering to complete the failure identification. The high resolution composi tional maps give a clear identification of the materials in the defect area and allows us to give some hypothesis about the origin of the circuit fail ure.