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On-Wafer Microwave Measurements

Traceability for scattering parameters in planar circuits

The rapid development of high frequency devices and IC technologies for wireless communication products has created many opportunities and challenges in RF testing, packaging and modeling. Until recently, the final test of RFICs in production was performed at the package level. In the meantime both the costs of package scrap have become prohibitive and the complexity of troubleshooting faulty chips has increased considerably because of electrical package parasitics. Therefore, complex RFICs are now being tested at the wafer level, prior to packaging.

Although on-wafer high-frequency measurements already have an economic impact on chip fabrication costs, there are no methods available for traceable on-wafer measurements in planar transmission lines - a problem which has been long solved in coaxial lines and waveguides. The need for traceable on-wafer scattering parameter measurements up to very high frequencies has also become evident in a recent survey conducted in industry and academia.

This topic is currently under investigation in the EMPIR Project 14IND02 PlanarCal — "Microwave measurements for planar circuits and components". PTB acts as project coordinator.