Measuring the electric and magnetic near fields in VLSI devices

This paper describes a technique for measurement of high frequency current distributions in microprocessors and other VLSI devices. The technique uses optical precision stepper motors for highly accurate placement of electric and magnetic field probes. Spatial resolution across a device is on the order of 100-200 micrometers. Typical scans accumulate 10000 data points across a scan area of approximately 35 mm/sup 2/. Characterizing a device involves a repeated series of spatial scans at harmonics of the fundamental clock frequency.