Inclined vs. Horizontal Waveguide Port Saver Approach in WR3.4 Band for On-Wafer Measurements

High frequency on-wafer measurements require waveguide based frequency extenders. As a company, FormFactor make extensive use of inclined frequency extenders, both coaxial single sweep and also banded Waveguide. The approach is very convenient for wafer probers where the platen is thermally optimized with insulation layers, to get the very best positioning stability for the probes and positioning mechanics. One key benefit of this approach is by their very nature, the extenders are further away from the hot wafer chuck which inherently should improve temperature stability. However up until this point our evaluation of these approaches was limited to 220 GHz and ambient conditions only. In the work we contrast and compare the stability of the inclined approach versus direct connected horizontal, both for the ambient and over temperature cases. T-wave probes and waveguide-based infinity probes are used for observations in WR3.4 band.