Alternative process and support material for embedded fine-pad-pitch LSI package

Alternative processes have been developed that simplify the fabrication and improve the properties of the “SIRRIUS” package, a direct fan-out package that overcomes the problem of forming connections using flip chip bumps in LSI devices with an increasingly smaller bonding pad pitch and that does not increase the cost of the interposer substrate. Package separation using Cu etchant simplifies fabrication, base plate flatterning using a reverse-warpage apparatus makes the initial Cu base plate virtually flat, and use of an AlSiC base plate makes the SIRRIUS package 35% lighter than one with a Cu base plate. Use of these processes makes the SIRRIUS package even more attractive for the fine-pad-pitch LSI devices expected to replace flip chip ball grid array packages.