Investigation of different thermomechanical behaviours in one batch of QFN packages

This paper investigates the influence of the position of the QFN packages during manufacturing on their mechanical behaviour. The samples under test are representative of the final QFN products as they are extracted from uncut moulded leadframes. They are identified depending on their position towards the point of moulding injection. This study focuses on the granulometric and mechanical analysis of the Epoxy Mould Compounds (EMC) used for this packaging technology. The results show different filler distribution in the EMC, as well as different CTE and flexural modulus values of the EMC depending on the samples position. Moreover, this paper also proves the influence of that dispersal in the moulded leadframes on the overall thermomechanical behaviour of the QFNs depending on their position during manufacturing.