Circuit edit has been instrumental to the development of focused ion beam (FIB) systems. FIB tools for advanced circuit edit play a major role in the validation of design and manufacture. This chapter begins with an overview of value, role, and unique capabilities of FIB circuit edit tools for first silicon debug. The etching capabilities of circuit edit FIB tools are then discussed, providing information on chemistry assisted etching in silicon oxides and low-k dielectrics. The chapter also discusses the requirements and procedures involved in edit operation: high aspect ratio milling, endpointing, and cutting copper. It then provides an...