Flatness enhancement of the embedded interposer of 3D-ICs by using ring-type framework designs

To resolve and simplify the critical assembly issue regarding the interposer of 3D integrated circuits (3D-ICs), a prototype of an embedded interposer carrier (EIC) is developed and demonstrated. However, the serious warping induced during the laminating process of multi-stacked organic films needs to be resolved to achieve good co-planarity of the EIC assembled by either dies or a printed circuit board. Hence, a unique design with an additional ring-type stiff frame is proposed and introduced into EIC fabrication. Through process-based simulation combined with the full factor design approach, a restraint for the warping of EIC lower than 14.24 μm is estimated; a steel-made ring-type frame combined with suitable conjugations of laminated materials is considered. Analytic results reveal that laminated layers having high elastic modulus and a small coefficient of thermal expansion are useful in moderating EIC warping. Consequently, the assembly reliability of 3D-ICs through EIC technology is expected to increase significantly.