Investigation of warpage induced on molded strip of QFN package

Warpage is known to be one of the primary molding issues during assembly of QFN package. It affects the package sawing process, and cause reliability issues. The main cause of warpage of area array packages is the coefficient thermal expansion (CTE) mismatch between the moulding compound and other components inside the package. The objective of this study is to investigate the warpage induced on the moulded strip of QFN package, by using different mold compounds which have different CTE values. The effect of thermal properties and filler content is also investigated. In this study, the QFN strips are moulded with different mould compounds. Nonlinear large deformation finite element analysis is performed to compare with the experimental result. It shows that different mould compound properties will result in different warpage