Applications of film over wire and die attached film in a stacked chip scale package

The demand of light, thin, short, and small chip in electronic industry has made investing considerable amount of human and material resources as to improve the chip density to match the thin structure loading specifications. Also, the general electronic configuration of traditional plastic containers can be improved by using a paste with good wettability, good dielectric properties, and inexpensive features. For the practical application of thin surface specifications, these pastes have no longer to meet the strictly demand. The trend of the electronic packaging area is required to reduce the package size and to improve the performance and advance integration. In this study, the film type die attach material applied in the stacked chip scale package (SCSP) has been discussed. The material of stacked died package structure was selected by using two types of film, DAF (die attach film) and FOW (film over wire) for evaluation the material characteristic and applied representation in the stacked die package structure. To characterize the thermal analysis and package structure, the following instruments were used: Differential Scanning Calorimetry (DSC) - Thermogravimetry (TGA) - Mechanical Analysis (DMA & TMA), and Field Emission Scanning Electron Microscope (FE-SEM). The thermal analysis instruments were used to analysis the curing reaction, residual heat of reaction, filler content, flow curves and softening points. The thermal analysis and Rheology data showed that FOW had more filler content, lower initial reaction temperature, longer working window and better viscosity presentation; it also indicated that FOW had well structure and workability. The results of micro structure analysis revealed that the small, uniform and circular filler existed in the FOW and the filler size of FOW is 1/3 than DAF, which can enhance structure strength and provide good flow condition, but it doesn't damage the die surface.