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World's first calibration certificates for on-wafer measurements

  • Metrology for Economy

PTB is the first national metrology institute in the world which has issued calibration certificates for on-wafer measurements. PTB has estimated a comprehensive uncertainty budget for S-parameter measurements of devices on a commercial alumina substrate, including instrumentation errors, connector repeatability and calibration standard uncertainties. For the first time, traceability on commercial calibration substrates was established.


Traceability is the basis for credible measurement results and associated uncertainties. It is driven by today's global business requirements and is typically achieved through an unbroken chain of comparisons to stated references, usually by standards from National Metrology Institutes (NMIs) or accredited laboratories. For S-parameter measurements on coaxial and rectangular waveguides, traceability to dimensional measurements has been established for several years, although challenges remain at higher frequencies due to shrinking connector sizes.

However, on-wafer S-parameter measurements face several additional challenges. Planar devices and calibration standards are fabricated on a variety of substrate materials using a wide range of technologies, and instead of standardised connectors, microwave probes from different vendors are commonly used. Reliable uncertainties can only be specified for a specific combination of substrate material, planar waveguide type, and probes, and only when single-mode propagation is ensured.

To address these challenges and to improve calibration accuracy in the mm-wave frequency range, the company MPI Corporation has designed, manufactured, and optimised a calibration substrate that reduces the parasitic effects associated with measurement probes, parasitic modes, and radiation. The calibration substrate was characterised at PTB, including S-parameter measurements, broadband extraction of the complex permittivity, dimensional measurements, and uncertainty estimation. A comprehensive uncertainty budget for on-wafer S-parameter measurements of devices on this calibration substrate was determined, including instrumentation error, connector repeatability, and calibration standard uncertainties. The traceability method for on-wafer measurements was successfully applied to a commercial, customised calibration substrate. Calibration certificates for a commercially available calibration substrate, suitable for on-wafer measurements in industry, were issued for the first time worldwide (see Figure).

Official handover of the calibration certificates at the European Microwave Week 2023 in Berlin (left) and exhibition at the stand of the customer (right).

Figure: Official handover of the calibration certificates at the European Microwave Week 2023 in Berlin (left) and exhibition at the stand of the customer (right).


U. Arz, G. N. Phung, and A. Rumiantsev, Opens external link in new window"Traceable Lumped-Element Calibrations up to 110 GHz on Commercial Calibration Substrates" in 2023 100th ARFTG Microwave Measurement Conference (ARFTG), Las Vegas, NV, USA, 2023, pp. 1-4.



Opens internal link in current windowDepartment 2.2 “High Frequency and Electromagnetic Fields”


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