Thermo-Mechanical Modeling to Analyze Package Stress of QFN Package

The QFN (Quad Flat No-Lead) package is probably the preferable choice of semiconductor package today. This is due to its advantages which are low cost, small form factor, excellent thermal performance and also have solid electrical performance. Therefore these features of QFN are an ideal choice for many new applications where weigh, size as well as thermal & electrical performance are important. Even though the advantages of QFN are well documented, however concerns arise with its reliability and manufacturability. Eliminating delamination which leads to package crack has become a necessity to get a robust IC packaging. Delamination in IC packaging would produce subsequence problems like broken wire, lifted wire bond stitch and package crack. This paper aims to investigate the effect of package stress on material selection as well as die attach fillet coverage through thermo-mechanical modeling using (FEA) finite element analysis. The FEA prediction results will be correlated using actual case study in order to fully understand the effect and the trend.