Improving the FE simulation of molded packages using warpage measurements

Study on the Strip Warpage Issues Encountered in the Flip-Chip Process

“…To match the materials on the production line, the bump was simulated as SAC405 (95.5Sn:4.0Ag:0.5Cu) and the die as being silicon. As shown in Table 4 and Table 5 , the most important issue was based on [ 8 , 9 , 10 , 12 ]. The mold compound is a polymer material, whereas the substrate is composed of different materials, so it has varying mechanical and thermal properties due to differences in ambient temperature.…”

“…The CTE measurement results obtained for the substrate agree with the IPC-4101 specification [ 23 ]. Unlike related studies [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ], this study input the temperature variation curves E(T) and α(T) of mold compounds and the substrate into the simulation model, which ensured that the material parameters of the simulation model were close to the actual situation.…”

“…In addition, they proposed the use of mechanics of composite materials theory for calculating the CTE of a substrate and mold compound at 25, 150, and 260 °C. Huber et al [ 12 ] employed an FE simulation to determine the effect of mold compound on warpage after a long period of thermal aging. Bin et al [ 13 ] applied FE simulation to fine pitch ball grid array packaging technology; they also discussed the effect of the geometric thickness of the mold compound and die on warpage when a strip was subjected to the molding process.…”

“…Severe strip warpage occurring during the post-molding period reduces product yield. The literature [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 20 , 21 , 22 ] indicates that FE simulation is frequently used to solve packaging warpage problems. Material parameters are crucial for determining whether consistency between simulated and experimental values is achieved.…”

A New Approach for the Control and Reduction of Warpage and Residual Stresses in Bonded Wafer

“…Warping can also be observed after the application of the moulded package, see e.g., [ 24 ], and in processes where each single die is bonded to a substrate wafer, see e.g., [ 22 ]; in this work, we will concentrate on glass frit, a common bonding material, extensively used in the MEMS industry [ 7 , 8 ]. Because of the relevance of the mechanical and thermal coupled behaviour on the warping, in Section 2 , the outcome of an experimental campaign on glass frit is summarized.…”