Masanori Motegi

Shape prediction and residual stress evaluation of BGA and flip chip solder joints

In this paper, several solder joint shape prediction methods are studied. There are various methods to predict the solder joint shape, such as sphere approximation, analytical calculation based on equilibrium surface tension and another forces, and finite element simulation code like Surface Evolver developed by Ken Brakke. Authors calculate shapes of BGA and flip chip solder joints by three methods and confirm the validity of each methods. After that, we calculate solder joint residual stress at solder solidification process by general stress simulation FEM code for each solder shapes, and analyze the assembly parameters effects to the solder residual stress by statistic analysis.

Automatic Thermal Modeling for System Level Design of Electronic Equipment

The development of hardware needs cost reduction by shortening a development period and reducing experimental man-hour. In order to satisfy these demands, thermal fluid analysis with higher accuracy in short time is indispensable for product development. At present, thermal fluid analyses are conducted using different software tools. Each software tool requires model building and meshing for simulations using its own format. That leads to a large investment in time, and therefore cost. VPS/Simulation-Hub software Fujitsu developed is able to convert data from various CADs. It has the features to create a data fitting to numerical analysis software, create an accurate analysis model, and delete unnecessary components. With these main features, VPS/Simulation-Hub greatly contributes to the man-hour reduction for model building and the improvement of analytical accuracy. In this paper, VPS/Simulation-Hub is introduced with the detail explanation of the above 3 main features.Copyright