Design of non-contact 2Gb/s I/O test methods for high bandwidth memory (HBM)

This paper presents a HBM device which verifies DC and AC characteristics of I/O circuits without direct contact on the u-bump. To verify DC and AC characteristics internally, design for excellence (DFx) circuits are implemented. Also, to perform accurate impedance calibration without ZQ pin, reference resistor calibration logic is embedded. In comparison of DFx AC result and automatic test equipment measurement result, it is confirmed that the DFx AC operation is well correlated with normal operation up to 2Gb/s.