Integration of SAW RF Rx filter stacked on a transceiver chip in a QFN package

Enhanced integration of mobile phone components is driven by demands for reduced form factor and cost. Because SAW filters must be fabricated on piezoelectric substrates, they are difficult to monolithically integrate on semiconductor chips. Here we report on the integration of a compact wafer-scale packaged SAW filter stacked over a transceiver chip in a quad flat-pack no-lead (QFN) package. An integrated passive device interposer provided redistribution and matching. We demonstrated the successful integration of both EGSM and DCS filters in such modules. SAW compact models based on the coupling of modes model were developed to facilitate system design.