Characterization of flip-chip interconnection for high speed digital transmission

This paper presents RF characterization of flip-chip interconnection in complementary-metal-oxide-semiconductor (CMOS) and glass-integrated-passive-device (GIPD) substrates by means of on-wafer scattering parameter (S-parameter) measurements, with high-speed digital transmission performance evaluations. The off-chip calibration is done firstly to shift the measured reference plane to the probe tips using the commercial impedance standard substrate (ISS) with line-reflect-match (LRM) method. Then the L-2L deembedding technique is applied for the two GIPD transmission lines to extract the RF characteristics of GIPD probe pads and transmission lines. Finally the designed thru-reflect-line (TRL) calibration standards in the CMOS chip are measured for resolving the flip-chip interconnection characteristics with the previous acquired GIPD parameters. The extracted data in two-port S-parameter are thereby simulated in time-domain to observe the high-speed digital transmission performance in eye-diagram representation. The shown result indicates the transmission speed in 40 Gbps works well in this flip-chip interconnection case.