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

•An embedded interposer carrier (EIC) is developed and demonstrated.•Warpage issue of EIC is addressed by proposed ring-type framework.•The warp of EIC is estimated and validated by simulations and experimental inspection.•A steel-made ring-type frame with suitable conjugations of laminations is preferred.•A significant reduction in warping lower by 14.24 μm for EIC can be achieved.

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.

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