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The recent development of focused ion beam systems with image resolution in the 20 nm regime has made practical a new process monitoring discipline, in-line x-y-z metrology. At any step in the wafer fabrication cycle, it is now possible to rapidly image a top view or cross sectional profile of the exact location on a chip or test structure where monitoring is required. For example, one can examine metal and oxide step coverage, via dimensions, resist profiles, metal grain size, or film quality. Under computer automation, any region on an 8' wafer can be located. A hole several microns deep and wide can be milled at this site, the wafer tilted up to 60 degree(s), and the walls of this hole imaged at magnifications approaching 70,000 times. Any arbitrary sequence of steps may be linked together to define a procedure which could be applied to wafer after wafer. Image information available during such a sequence can be uploaded to a host computer and statistical process control methods applied to the image parameters of interest. In this paper we describe the characteristics of a new focused ion beam system, its hardware and software control, and typical results from the cross sectioning of a 4 Mb DRAM.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.