A near-field scanned microwave probe for spatially localized electrical metrology

We have developed a near-field scanned microwave probe with a sampling volume of approximately 10μm in diameter, which is the smallest one achieved in near-field microwave microscopy. This volume is defined to confine >99% of the probe’s net sampling reactive energy, thus making the response virtually independent of the sample properties outside of this region. The probe is formed by a 4GHz balanced stripline resonator tapered down to a few-micrometer tip size and provides noncontact, noninvasive measurement capability. It is uniquely suited for spatially localized electrical metrology applications, such as evaluation of Cu/low-k interconnects on semiconductor production wafers.