Thermomechanical Properties of Fan-Out Wafer Level Package Fabricated with Various Epoxy Mold Compound

Fan-out package has advantages such as higher I/O density, higher electrical performance, ultra-thin and low power consumption. However, Fan-out package have some issues caused by warpage induced by difference of coefficient of thermal expansion between epoxy mold compound (EMC) and Si die. Therefore, the warpage behavior of the FOWLP component molded with three kinds of EMCs were investigated by using shadow moiré method and finite element method analysis. The environmental reliability of fan-out package component was evaluated by thermal shock test and temperature-humidity test. The warpage behavior of fan-out package component changed from convex to concave with increasing the temperature. The warpage of fan-out package component molded by EMC with lower CTE was reduced because of smaller CTE mismatch between chip and EMC at room temperature. However, the warpage of FOWLP component molded by EMC with lower modulus was reduced the warpage even though CTE of EMC was higher than others due to stress-strain relaxation at 260°C. The electrical resistance of fan-out package component increased with increasing aging time and cycles during temperature-humidity test and thermal shock test.