Wafer-Level Contactless Testing Based on UHF RFID Tags With Post-Process On-Chip Antennas

This brief demonstrates a fully contactless wafer-level testing based on UHF radio identification (RFID) technology enriched by high-quality on-chip antenna. The antenna, which uses exactly the same tag IC area (i.e., 0.45 mm
²
), exploits a low-cost post-process consisting of a thick dielectric layer and a copper metal, thus significantly improving the quality factor with respect to a standard CMOS implementation. Contactless wafer-level testing of a tag array is performed by simultaneous inductive coupling with a customized near-field reader. With a 27-dBm standard UHF RFID reader, a reading range up to 2.5 mm is demonstrated at 865 MHz. Anti-collision algorithm and memorized x-y device coordinates allow IC identification on the wafer under test to be achieved. Thanks to its cost-effectiveness, the proposed approach can be easily extended to general purpose IC contactless testing.