Experimental and simulative study of warpage behavior for fan-out wafer-level packaging

Controlling warpage effects in fan-outwafer-level packaging (FO-WLP) is of key importance for realizing reliable and cost-efficient system in packages (SiPs). However, warpage effects can occur during the manufacturing process, caused by a combination of different processing temperatures, different materials, and the changing properties of the materials (e.g. polymerization and related cure shrinkage). One approach to controlling warpage could be realized by assessing a numerical simulation workflow of the FO-WLP process chain, in which the relevant material properties and geometry are used as input. Since there are many different steps included in the FO-WLP process, accompanied by complex material behavior, this workflow is not straight-forward. In the present paper, the first FO-WLP processing steps are investigated in detail by performing extensive thermo-mechanical material characterization, temperature-dependent warpage measurements, and numerical simulations. The investigation focuses on two epoxy mold compound (EMC) materials with completely different physical properties.