Novel Temporary Bonding and Debonding Solutions Enabling an Ultrahigh Interonnect Density Fo-Wlp Structure Assembly with Quasi-Zero Die Shift

Abstract

Next-generation temporary bonding adhesive material is introduced into imec's high interconnect density flip chip on fan-out wafer-level package (FC FOWLP) concept [1], [2]. After molding on silicon substrates, an ultralow die shift with an average of $< 2\mu \mathrm{m}$ die-to-carrier mismatch and warpage of $< 200\mu \mathrm{m}$ were achieved in a full 300-mm wafer. These values are orders of magnitude improvement over results reported in literature and has major implications on the processing of overmolded substrates. The combination of this low warp and ultralow distortion opens the possibility for fine-pitch RDL combined with a chip-first approach, which was impossible until now. The evolution of warpage and die shift through multiple processing steps will also be discussed in this paper.