Investigation on practical problems in on-wafer measurement for actual devices

The study investigates on some practical problems in on-wafer measurement for actual-used devices in the millimeter-wave (mm W) frequencies. In terms of thickness of metallization, it is noted that range of the tilt angles, which probe is correctly contacted on surface of metallization, is decreased with thickness of the metallization being thinner. Range of the tilt angle was only 0.25 degrees in worst case when thickness of metallization was 0.8 μm. Tilt of sample chuck and surface of sample cause difference in probe positions in vertical directions of several microns, and results in difference in measured transmission coefficients of a CMOS device which were ranged from −3.2 dB to −4.4 dB. Finally, RF signal detection (RSD) technique was applied for evaluation of four of CMOS chips. The RSD technique well-works even in the CMOS devices.