TABLE OF CONTENTS The past approach for high-volume wireless transceivers employed many separate packaged die placed on a motherboard with passives. The modular trend has modified the role of the package from die interconnect and protection to the complete RF system. In essence, the RF transceiver system that was once a printed circuit board (PCB) measured in units of a few inches has become the package measured in units of tens of millimeters [1]. This places all the requirements of the motherboard in previous designs into the package. New developments have recently been established to accommodate this task. Shields and antennas have been incorporated into the package. In a size-reduction effort, integrated passive network (IPN) have been developed on high-resistivity silicon and GaAs substrates as well as LTCC.
The traditional packaging approach incorporated the shield as the module lid, a one-metal can that was soldered or epoxied over all the circuitry, and this method is still used. The metal lid can be drawn or stamped. A stamped shield typically covers only one compartment in a rectangular shape. However, a multicompartment stamped shield design is possible with large holes in the shield (see Figure 4.1). This may be acceptable, depending on the shielding requirements and frequencies. A drawn shield is usually required to meet more stringent shielding requirements. In either case, die protectant is still needed, with the usual candidates being glop or dam and fill. Both are more expensive operations with fewer units per hour (UPH) than overmold. A low-cost shielding...
