Improving Wafer-Level Calibration Consistency with TMRR Calibration Method

This paper presents the new calibration algorithm TMRR (Thru-Match-Reflect-Reflect), the extension of the Thru-Match-Reflect (TMR) method with one extra Reflect standard. The algorithm was developed to reduce the impact of an asymmetrical placement of RF probes on coplanar probe-tip calibration standards on consistency and reproducibility of calibration results often observed for an inexperienced system operator. The introduction of an additional Reflect calibration element to the TMR algorithm increases the measurement information redundancy, and thus reduces the calibration error caused by possible asymmetry in reflection coefficients of lumped standards. The new method was verified for simulated data as well as for an InP DHBT device operating in the “off-state” regime.