Fan-out Wafer Level Package for Memory Applications

Recently TSV technologies have been widely used in high bandwidth memory for high performance computing or graphics applications and high density memory modules for DDR4/DDR. In mobile memory package, wire bonding technology has been still used due to high manufacturing cost of TSVs and performance compatibility of conventional wire bonding technologies. However, the conventional mobile package may have several challenges of thinner package or better thermal and electrical performances as the overall mobile system performance is improved.In this paper, HIFOM (Hynix Integrated Fan-out Memory) as chip stackable fan-out waver level package will be introduced as thinnest packages with better thermal, mechanical, and electrical performances than conventional wire bonding type memory packages. This innovative package has thinner z-height of 15~20% less than conventional wire bonding based BGA packages by elimination of organic substrates. For thermal and mechanical characterization, thermal resistance and warpage of a package were evaluated. Channel characteristics of memory chips were evaluated and it was found that the package had enhanced timing margin and PDN impedance compared with the wire bonding type packages.