US Patent 8952544 Semiconductor device and manufacturing method thereof

A fan-out package includes a molding compound, a conductive plug and a stress buffer. The conductive plug is in the molding compound. The stress buffer is between the conductive plug and the molding compound. The stress buffer has a coefficient of thermal expansion (CTE). The CTE of the stress buffer is between a CTE of the molding compound and a CTE of the conductive plug. A method of manufacturing a three dimensional includes plating a post on a substrate, and disposing a stress buffer on the sidewall of the post. The method further includes surrounding the stress buffer with a molding compound.