Effect of ZnO on dielectric properties of Li-Al-Si photoetchable glasses as an interposer

Abstract

Abstract In current three-dimensional (3D) radio frequency (RF) package field, the silicon interposer can’t entirely meet the needs of the package because of its non-negligible dielectric loss. Similarly, the application of through Glass vias (TGV) has restriction for the same reason. Therefore, this paper focuses on reducing dielectric loss of photoetchable glass (PEG), as well as the performance of TGV technology of PEG for packaging. The PEG was reduced in the dielectric loss by the addition of ZnO. The reduction in dielectric loss is due to changes in structure. The structure of PEG was analyzed through the XRD and the Raman spectroscopy. The dielectric performance was verified by the Impedance Analyzer. The result indicated dielectric loss obviously decreased to 0.0035 by ZnO doped and the reason primarily attributed to the decrease number of the Non-Oxygen-Bridge in the glass network and the structure is more stable. Through thermal processes and etching, the average diameter obtained around 75μm by TGV, and the aperture ratio of up to 25: 1, TGV density can reach 10000 / cm2.