Embedded IC technology for compact packaging inside aluminum substrate (Pocket Embedded Packaging)

Various technologies have been developed to package microwave systems to achieve low-cost, high-integration, better RF performance and good thermal dissipation. In this paper, we propose a new type packaging technology, "pocket embedded Packaging (PEP)", using selectively anodized aluminum substrate. In this technology, chips can be embedded inside aluminum substrate so that ultra thin and compact type of package can be achieved. More than 120 mum thick aluminum oxide (Al₂O₃) is selectively anodized on an aluminum substrate with 5% oxalic acid electrolyte. This thick aluminum oxide (AI₂O₃) can be chemically etched with vertical side walls. Rectangular-shape of opening area, which we named "pocket" is easily formed inside aluminum substrate. After the formation of the pocket, active chips can be embedded inside it with a tolerance of less than 3 mum. Passive components on an aluminum oxide (Al₂O₃) are interconnected with active chips through metallic interconnections.