Recently, adhesive material, called DAF (Die Attach Film), has become indispensable for stacking die in SiP (System in Package) used for mobile devices, and for stacking memory devices in flash memory. Typically, DAF is attached to the backside surface of a thinned wafer, and then singulated at the same time in the next process of wafer dicing. In doing so, problems, such as cross-sectional cracking, may occur