Comparative study on the reliability of QFN and AAQFN packages

Quad flat no-lead (QFN) packages are widely used in portable electronic products due to its excellent performance and lower cost. The electrical connection of QFN package is accomplished through solder-paste printing and it includes an exposed thermal pad to improve heat transfer. In addition, with the development of package technology, the pitches of QFN packages are designed smaller and multi-row QFN are becoming more and more popular. However, the reliability of QFN packages has not been well studied, especially those with multi-row I/O and fine pitch size. In this paper, two AAQFN packages (the I/O pads were replaced by solder balls) and two QFN packages were tested in temperature cycling according to JEDEC standard. All these four packages are molded and the two QFN packages has two-row I/O and with different package sizes. In order to compare the reliability of AAQFN and QFN, Weibull curves were drawn and their characteristic lives were obtained. Furthermore, failure analysis was carried out to find out the failure modes of the AAQFN and QFN packages.