Thermal characterization of a thermally enhanced QFN package

This paper addresses the development of thermally enhanced (advanced) Quad Flat No lead or QFN package. The QFN package is a promising choice for portable wireless applications such as Bluetooth and Home RF. This package offers attractive attributes in terms of a near CSP footprint, good electrical and thermal characteristics. Thermal characterization of a new thermally enhanced QFN type of package named as HQFN. The HQFN package structure is similar to a normal QFN package except that it has an exposed heat spreader attached to the active die using a die-attach film (DA film) material. The study is done in comparison with a normal QFN type of package using commercial CFD simulation software and validated with experiments. Sensitivity analysis is made for the effect of DA film material thermal conductivity and effect of heat spreader size. The new HQFN package is able to achieve a better thermal performance than normal QFN without thermally saturating the PCB. Simulation results show that with a metal housing attached to the top of the package, it is possible to achieve thermal improvement of more than 20% under airflow conditions, and around 10% improvement under still-air conditions, when compared to a normal QFN package under the same test conditions.