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A novel Wafer level Fan-out Package (WFOP™) applicable to 50um pad pitch interconnects

We present a new embedded package structure and technology for the next generation of WLP, the Wafer level Fun-Out Package; WFOP™. That is one of the face-down mounting styles, which has metal plate like stainless or copper as a base plate of redistributed interconnection layer. The redistributed layer is fabricated with semi-additive method of copper plating. The contact type between the die pads and distributed layer is the lead-type. This structure is hopeful to reduction of fabrication cost by using large scale panel and precise redistribution interconnects control, and its design rule does not depend on the die size. Moreover, WFOP™ has several benefits; applicable to 50µm pad pitch, an excellent thermal characteristics and noise shield by attaching the metal plate. And we obtained the fine results of reliability test. In this paper, we report its package structure, process flow, package characteristics and reliability test results and discussion.