Today cmWave (3-30GHz) and mmWave (30-300GHz) applications have become mainstream. Packaging has become obsolete and wafers are becoming the new final test package. Testing automotive radar on wafer at 80 GHz and 150 degC was previously a fantasy, but is now a reality. With high power simulation tools and 110 GHz VNA’s it’s possible to design and fabricate hardware for these extremely high frequency, high temperature applications.
This paper will introduce a new and extremely robust solution to test wafers cmWave and mmWave applications. The new WLCSP xWave probe card incorporates the shortest impedance controlled path from the Tester to the DUT. The hybrid cantilever and pogo technology bypasses the PCB for high speed signals and uses pogo pins for power and low speed signals. Combining technologies provides the longest life, most robust solution available for high speed wafer testing.
An introduction to the cmWave and mmWave markets will be followed by the challenges that had to be overcome to take the xWave technology from final test applications to wafer test. Optimization of the signal path for the best signal integrity and force characteristics will be described. The full assembly will be broken down to describe functionality and field maintainability. Finally test data will be presented to prove the technology functions in extreme frequency and temperature environments.