Microwave characterization and comparison of adhesive flip chip interconnects

摘要

S-parameter measurement and impedance parameter extraction of adhesive flip-chip interconnect were performed using a microwave network analysis. A test flip chip was assembled on a PCB substrate using anisotropic conductive adhesives (ACAs). S-parameters of on-chip and substrate were separately measured in the frequency range of 200 MHz to 20 GHz using a microwave network analyzer HP85 10 and cascade probe. And the cascade transmission matrix conversion was performed. The same measurements and conversion techniques were conducted on the assembled test chip and substrate at the same frequency range. Then impedance values in ACA flip-chip interconnection were extracted from cascade transmission matrix. By using this extraction procedure, low-k filler(SiO{sub}2) incorporation effects & bump metallurgy(Ni, Ni/Cu bilayer) effects on high frequency behavior of ACAs were investigated and quantitatively compared that of stud bump flip chip interconnects. The extracted model parameters of adhesive flip chip interconnects were analyzed with the considerations of the characteristics of material and the design guideline of ACA flip chip for high frequency applications was provided.