Minimizing System Drift in mmWave Wafer-Level Testing with Active Thermal Management

Precision in millimeter-wave (mmWave) device characterization is significantly i nfluenced by sy stem dr ift, particularly in setups where temperature variations are substantial. Key components of the wafer-level test system, such as mmWave frequency extenders, waveguide RF probes, and waveguide sections, are susceptible to thermal-induced drift, which directly impacts measurement accuracy and necessitates frequent recalibration. This work presents an integrated advanced ThermalShield <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${ }^{\text{TM}}$</tex> and Probe ThermalProtector <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${ }^{\text{TM }}$</tex> solution designed to stabilize the temperature of critical system components by employing active air purge shielding and active cooling of waveguide sections and RF probes. Our approach effectively reduces drift, significantly improves measurement accuracy, and enables long-term device characterization across a wide temperature range of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-40^{\circ} \mathrm{C}$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$+175^{\circ} \mathrm{C}$</tex> and chuck positions. We demonstrate that the proposed method reduced drift errors from as high as <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$80 \% E V M$</tex> to an average of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$10 \%-13 \%$</tex>, depending on test conditions, facilitating precise on-wafer measurements with minimal required recalibration.