Effects of the resin's thermal conductivity on temperature of the qfn64 electronic device subjected to free convection

Abstract

The reliability, durability, performance and correct operating of the quad flat non lead 64 (QFN64) packages are directly linked to their thermal state. In some works published recently, the thermal conductivities of the materials constituting the package are assumed as isotropic and temperature independent, corresponding to the average values considered in similar studies These important characteristics can however vary depending on the manufacturing process of the device and the used materials. The molding compound's thermal conductivity (resin) used for encapsulating the QFN64 package significantly affects the thermal behaviour of this electronic package during operation when it is subjected to natural convection. These effects are quantified in this work by varying this conductivity between -80% and + 80% of its average value. The 3D numerical solution done by means of the control volume method clearly shows that the maximal temperature reached into the source of this device is affected by this parameter for a wide range of the generated power and various inclinations of the device relative to the horizontal. The correlation proposed in this work allow optimizing the thermal design and increase the reliability of this electronic device widely used in various engineering fields.