Thermal modeling of WLP-BAW filters: Power handling and miniaturization

We present efforts and methods to model the thermal behavior of wafer level packaged (WLP) bulk acoustic wave (BAW) filters. Many key parameters of modern RF filters are temperature dependent. Excessive self-heating, especially in TX-path filters, can lead to severe performance degradation. Even more fatal, unrecoverable failure conditions can occur. Having supportive data early-on in the design phase of a filter is crucial. It saves expensive and time-consuming design iterations and thus gives margin for more efficient and reliable filter development. The presented simulation method offers the advantage of incorporating the effects of the module geometry into the thermal simulation. Not only the die layout is considered, but, for example, also the impact of different laminate variants can be studied. Additionally, it allows simulations to run with traditional circuit simulator speed for different stimuli i.e. CW-tones at different frequency positions.