On wafer measurements

Measuring key parameters of integrated circuits and devices

Accurate on-wafer measurement is critical in the production of high quality, cost effective and assured integrated circuits for established and emerging applications, such as communications, electronics, security imaging, radio astronomy, medical and healthcare technologies. On-wafer measurements allow the evaluation and measurements of the device and its manufacturing process, and therefore the ultimate performance.

Scattering parameters, or S-parameters, are used to characterise electrical devices especially when you are measuring the frequency and amplitude of the wave, rather than current and voltage. Measuring the loss and phase change for transmitted and reflected signals are fundamental and critical electrical measurements for the characterisation of integrated circuits. These types of measurements are particularly challenging at high frequencies.

NPL supports industry and academia by using on-wafer S-parameter measurements and provides test facilities and consultancy for many applications.   We are also actively involved in a wide range of collaborative research projects, and investigations into innovative test applications and processes involving on-wafer measurements.

High frequency on-wafer calibration and measurement underpin technological development of integrated planar circuits which are in widespread use for a large variety of applications. Examples include high capacity mobile backhaul links operating at 71 GHz to 86 GHz, automotive radar sensors at 77 GHz and space deployed radiometers for remote sensing of atmospheric constituents related to climate change with channels operating at frequencies from around 20 GHz to above 200 GHz.

Authoritative leader in research

NPL is currently leading a large-scale European project, TEMMT, dedicated to advancing measurement techniques, including on-wafer measurement techniques, at millimetre-wave and terahertz frequencies. We were also actively involved in the PlanarCal European project, which ran from 2015 to 2018, devoted to the development of on-wafer measurements for planar circuits at microwave frequencies.

Read our Introductory guide to making planar S-parameter measurements at millimetre-wave frequencies

Download Best practice guide for planar S-parameter measurements using vector network analysers

NPL has been collaborating with Filtronic on on-wafer measurements at millimetre-wave frequencies since 2017,You can read more about this work below and if there are projects you’d like to discuss please free to contact us using the link at the bottom of this page.

Moving up in frequency – Why D-band is the next frontier for X-haul

Calibration techniques for on-wafer S-parameter measurements

Unique capability

NPL can undertake ground breaking research due to its unique laboratories and test equipment, including: 

• MPI TS-150 THz probe station which is a state-of-the-art system that enables accurate on-wafer measurement up to terahertz frequencies. The probe station also includes a thermal chuck (for measurement over temperature from 25 °C to 150 °C) and ceramic and metal chucks (for measurements with different boundary conditions).
• Keysight PNA-X N5247B vector network analyser (10 MHz to 67 GHz) and VDI frequency extension modules, enabling two-port S-parameters measurements up to 750 GHz. Additionally, extension modules are available for waveguide bands: 50 – 75 GHz, 60 – 90 GHz, 75 – 110 GHz, 110 – 170 GHz, 140 – 220 GHz, 220 - 330 GHz, 500 – 750 GHz. These can also be integrated into the probe station.
• Probes (with integrated bias-tee) and calibration substrates are available for the all frequency bands.
• VDI Erickson PM5 power meter allows power measurement from 75 GHz to a few terahertz.
• PNA-X equipped with noise figure option 028, allowing noise figure measurements up to 26.5 GHz.

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