3D RF front end module packaging using anodized aluminum substrate

Abstract

This thesis describes the design and fabrication of 3-D packaging of dual band WLAN FEM using anodized aluminum substrate. In the first chapter, technology trends on RF system integration were reviewed. And a brief introduction of selective anodized aluminum (SAA) substrate was presented. In second chapter, a 6 inch wafer based RF passive foundry using SAA substrate was introduced. It has 3 metallization layer of copper, a silicon nitride dielectric layer and an organic interlayer and a passivation layer. Using a microstrip ring resonator method, the dielectric characteristics of the SAA substrate were analyzed. The extracted relative permittivity was 6.82~7.0 and loss tangent was 0.0065~0.0142 without considering radiation loss. A 5.4GHz balanced BPF was designed, simulated and fabricated using 6 inch RF passive foundry on SAA substrate. The measured center frequency was 5.1GHz, and insertion loss and return loss at the center frequency was 2.6 dB and15 dB respectively. And AD was 0.03dB and PD was 0.1˚ at 5.1GHz. The extracted dielectric characteristics and measured performances of the balanced BPF show that the SAA substrate for RF passive foundry are very competitive and have enough capability to be a solution for RF system integrations. In the third chapter, a 3-D interconnection method using vertical via on the anodized aluminum was proposed. The fabrication process flow was designed. A modeling procedure to extract equivalent circuit model of the vertical interconnection using the double delay de-embedding algorithm and curve fitting was proposed and verified based on 3-D EM simulation. The extracted RLCG values were 35mΩ, 169.1 pH, 57 fF and 0.012mS respectively at 2GHz. A 2.4GHz single band WLAN FEM and a 2.4/5.4GHz dual band WLAN FEM using SAA substrate were designed and fabricated. Using selectively anodized aluminum substrate, it was possible to realize compact FEMs with highly integrated passive devices as hybrid IC packages. The sizes of FEMs ar...