RF-behaviour of anisotropic conductive adhesive in wafer-level packaging for RF-MEMS
More Info
expand_more
Abstract
In this work, an anisotropic conductive adhesive (ACA) used for wafer-level bonding in RF-MEMS packaging is investigated in respect to its influence on RF behaviour of packaged MEMS structures and transmission lines. The packaging solution explored is based on a wafer level packaging (WLP) approach where a capping high-resistivity silicon substrate containing vertical interconnect is adhesively bonded to an RF-MEMS wafer using ACA. After ACA bonding, conductive metal particles within the epoxy based matrix either contribute to the electrical path formation or, when uncompressed, remain isolated. Influence of such isolated particles on RF performance of adjacent structures has been studied using Ansoft HFSS electromagnetic simulator. The results show that the ACA layer might adversely affect performance of RF transmission lines by introducing additional losses.
Keywords: ACA, WLP, RF MEMS, hybrid packaging.