A wafer-level package of wideband microwave transmission system based on BCB/metal structure embedded in Si substrate

摘要

In this paper, a wafer-level package for a microwave transmission system has been implemented and tested. Three monolithic microwave integrated circuits packaged in one microwave system are first proposed. The packaged system consists of an up-converter, a drive amplifier and a power amplifier. All the modules are embedded in the cavities pre-etched in a low-resistivity silicon substrate. Benzocyclobutene layers are coated on the components and silicon substrate, serving as interlayer dielectrics. Gold bumps are used as electric interconnections between different layers. Gold micro-strip lines are employed as transmission lines. The electrical properties of the packaging structure are investigated. The design procedure is proposed and the simulation regarding transmission line has been done. The thermal property of the packaged system is simulated and detailed discussion is presented. The measured transmission characteristics of the packaged system shows that the modules can work at very wide band, at the range of 6-18 GHz (X/Ku band) and its gain agrees well with the theoretical results.