Abstract

Currently, the thin film microwave multi-chip module (MCM) technology offers many benefits for a compact, lightweight and low cost integration of RF and microwave circuits [see Carchon et al (1)]. This technology allows the realisation of low loss transmission lines with a variety of characteristic impedances (between 10 and 100 Ohm) up to the higher mm-wave frequencies (>50 GHz). The technology also allows mounting active circuits (such as MMICs) by e.g. flip-chip technology. However, when placing different functions closely together, an adequate shielding and also mechanical protection of the active dies may be required. For this purpose, we developed a wafer level (called 0- level) package concept using micromachined cavities to realise versatile, microwave compatible protection and shielding structures on the thin film substrate. 0-level packaging refers to packaging before separation of the dies of the thin film integration substrate. In order to illustrate this concept and the benefits in real microwave functions, the realisation of a Ka-band LNA module, including 0-level package, bias circuits and RF feedthrough structures is discussed in this contribution.