Will Low-Cost 3D Additive Manufactured Packaging Replace the Fan-Out Wafer Level Packages?

Abstract

The fan-out wafer level package (FOWLP) became rapidly developed towards a major advanced packaging solution. This technology creates a mold cast to embed bare dies by compression molding. Subsequently this mold cast serves as a substrate for the redistribution layer. Unfortunately, with such technologies no rapid prototyping is possible. Certainly, applied pressure and temperature during the FOWLP process is a load to the dies regarding their reliability. Under these impressions, we applied additive manufacturing technologies by using 3D printers for rapid prototyping on Wafer Level Packaging (WLP) of multi-chip modules. Using additive manufacturing technologies the heat insertion on the dies is locally and temporally minimized within the process. With additive manufactured packaging the strict design rules of the mold cast will be reduced significantly. In this work, a low-cost 3D Additive Manufactured Package (3D-AMP) has been successfully achieved. By using a stereolithographic process, an IC less than 100 µm thick was embedded in a 3D free formable package. Furthermore, geometrical measurements demonstrate a good surface conviction (roughness) especially for a subsequent build-up of an additive manufactured redistribution layer. In addition to this, via openings may be already integrated in the free formable substrate manufactured by 3D printing. By performing an additional via filling with functional materials (optical and electrical), a fully additive manufactured 3D-stackable package can be realized. Additive manufacturing allows rapid prototyping of redistributed wafer level modules. Additionally, customized and potential low-cost fan out 3D integrated wafer level packages seem to become a serious additive manufacturing process. Presently, material selection and further optimization is the focus of our work. Already now, it seems 3D-AMP has a high potential to become a possible alternative process for FOWLP.