Thermal Performance Comparison between Various RF Transceiver Modules

A detailed numerical study was conducted to investigate the thermal behavior of three RF transceiver modules in a custom environment. The system incorporates the transceiver device and the high density interconnects (HDI) substrate at a fixed boundary condition. In general, the transceiver module requires lesser heat dissipation and thermal requirement may not be as critical as for the power amplifier (PA) module. However, its low thermally conductive die attach material, reduced size of the active areas (micron range) and fairly high power densities lead to the concern that the thermal budget (150 degC) may be exceeded under the various operating scenarios. Each transceiver module was modeled in detail including the device local discrete heat sources, the substrate metal layers, and micro and buried vias distribution across the dielectric layers. The impact of via locations in the substrate is also examined to address the die reliability issues. Results indicated that due to the low power dissipation, the predicted peak temperatures of all three Transceiver modules are below the 150 degC thermal budget. Analyses also suggest that the vias located directly under the die could be removed without any significant thermal penalty. Also, by strategically placing a few vias near the heat sources while removing rest of them in the substrate; it will still satisfy the overall thermal requirements. A detailed comparison between various transceiver designs and associated thermal performance is provided