Transmission property of adhesive interconnect for high frequency applications

The radio frequency (RF) and high frequency performance of the flip chip interconnects with anisotropic conductive film (ACF) and non-conductive film (NCF) was investigated by measuring the scattering parameters (S-parameters) of the flip chip modules. The effects of two chip materials, Si and gallium arsenide (GaAs), and of the metal pattern gap between the signal line and ground plane in the coplanar waveguide (CPW) on the RF performance of the flip chip module were also investigated. The transmission properties of the GaAs were markedly improved on those of the Si chip, which was not suitable for the measurement of the S-parameters of the flip chip interconnect. Extracted impedance parameters showed that the RF performance of the flip chip interconnect with NCF was slightly better than that of the interconnect with ACF, mainly due to the self inductance of the conductive particle surface and the mutual inductance between the conductive particles in the ACF interconnect.