TLP systems with combined 50 and 500-ohm impedance probes and kelvin probes

TLP systems are mainly classified by their impedance, such as 50 ohm or 500 ohm current source. A new TLP configuration allows switching between 50 and 500 ohm by computer control to characterize a given part using both impedances. In addition, a four-needle Kelvin technique is introduced to TLP, which overcomes the measurement error from variations in contact resistance where the probe needles contact the wafer surface.