On-wafer device characterisation test solution available now

21-07-2022 | Rohde & Schwarz | Test & Measurement

Rohde & Schwarz now provides a test solution for full RF performance characterisation of the DUT on-wafer, which combines the powerful R&S ZNA vector network analyser from Rohde & Schwarz with industry-leading engineering probe systems from FormFactor. As a result, semiconductor manufacturers can perform reliable and repeatable on-wafer device characterisation in the development phase, through product qualification and in production.

5G RF front-end designers strive to ensure proper RF capabilities for frequency coverage and output power whilst optimising energy efficiency. An important phase in this process is examining the RF design to get feedback on the design as early as possible and assess the performance and capabilities already on the wafer level. Characterising a DUT in an on-wafer environment needs a measurement system including a VNA, a probe station, RF probes, cables or adapters, a dedicated calibration method, and calibration substrates for the particular DUT or application.

To perform these fundamental measurements, the company supplies the high-end R&S ZNA VNA, which characterises all RF qualification parameters at coaxial and waveguide levels and frequency extenders for application ranges over 67GHz. FormFactor handles the wafer contact with manual, semi-automated and fully automated probe systems, including thermal control, probe positioners, high-frequency probes, and calibration tools. The calibration of the complete test system, including the R&S ZNA, is completely supported in the FormFactor WinCal XE calibration software.

In the test setup, the user has access to all test capabilities of the R&S ZNA, due to the fully calibrated setup. Generic S-parameter tests enable characterisation for filters and active devices, but distortion, gain, and intermodulation tests can also be conducted to qualify power amplifiers. Frequency translating measurements for mixers with phase characterisation over the device's bandwidth are another example of the supported measurement applications of the joint solution. The fully calibrated setups also permit all results to be directly taken from the VNA with no postprocessing as the calibration data are applied straight to the VNA. Frequency extenders from the company open up sub-THz frequencies such as D-band, which are currently in the focus of 6G research. The extenders will be integrated into the probe station to ensure the shortest cabling and enable optimal dynamic range while avoiding losses due to cabling to the probe tip.

By Natasha Shek