In this paper, test-vehicle for microwave measurement was fabricated using flip chip process. The s-parameters were measured up to 20GHz using network analyzer HP8510 and cascade probe.
In chapter 3, new model parameter extraction procedure for characterization of flip chip interconnects was proposed. At first, the cascade transmission matrix conversion was performed to extract the impedance of interconnects. After that, we applied the above proposed procedure to extract the model parameters of flip chip interconnect.
By using this extraction procedure, we analyzed the extracted model parameters of interconnect with the considerations of the characteristics of material and provided the design guideline for high frequency applications.
In chapter 4, low-k filler $(SiO_2)$ addition effects on high frequency behavior of ACF were mainly dealt with.
Both conductive particle and low-k filler $(SiO_2)$ were successfully incorporated into polymer matrix. Flip chip bonding of test-vehicle was performed by thermo compression bonding at 190℃ for 290sec. ACF (Anisotropic Conductive Film) including 30wt% $SiO_2$ exhibited higher resonance frequency than conventional ACF. This difference is recognized to be caused by epoxy capacitance reduction and verified by model parameter extraction.
Also, unstable contact of conductive particles was observed from the model parameter.
In chapter 5, bump metallurgy effects on high frequency behavior of ACF were investigated. Two bump systems, which are electroless Ni bump and electroless Ni/electroless Cu as a same bump height, are prepared by electroless plating. Both electroless Ni bump and electroless Ni/electroless Cu presented the same high frequency behavior. The only difference is that electroless Ni/electroless Cu bump system have small insertion loss at resonant frequency compared to electroless Ni bump. Therefore, metal bump system did not affect the high frequency behavior
In chapter 6, high frequency behavior of stud bumps using NCF (Non Conductive Film) was studied. Metal stud bumps are fabricated on Al pad using ball bonder. Stud bumped chip and test-board were flip chip bonded using NCF curing at 190℃ for 290sec.
Stud bumps did not exhibit the resonant phenomena in microwave frequency range. In other words, the impedance of stud bumps was constantly maintained up to 20GHz.
The results and discussions about flip chip interconnects in this dissertation could be used for microwave device fabrication and packaging, providing an important design guideline for material and process selection criteria.
