Custom-made calibration standards for measurements of multilayer substrates

In this paper the authors present custom-made calibration standards for microprobe based measurements on multilayer printed circuit boards. Non ideal short, open and load (SOL) terminations are positioned at the end of through holes (vias). The combination of via plus termination forms a custom-made standard for printed circuit board measurements. The load standard consists of a soldered 47 Ohm (SMD, 0402, 1%) resistor, a solder bridge is used as a short and for the open the via is left open. The usable bandwidth of the standards is studied with the help of a two-tier calibration method. Comparisons of measurements performed on the same device under test using either the microprobe vendor calibration substrate or the custom-made standards show good correlation in the frequency bandwidth from 10 MHz up to 30 GHz.