Thermal and mechanical design and analysis of 3D IC interposer with double-sided active chips

Abstract

In this investigation, the thermal and mechanical design and analysis of a TSV (through-silicon via) interposer which supports 2 active chips on its top-side and 1 active chip on its bottom-side (a real 3D IC integration with an interposer) are studied. Emphasis is placed on the thermal design and analysis of the chips' average temperatures and the applied cooling capability on the heat spreader/sink. To simplify the simulations, an equivalent model, that can preciously determine the thermal performances of TSVs and solder bumps/balls, is introduced instead of a complicate detail 3D model. Another emphasis is placed on the determination of the creep strain energy density per cycle of the solder bumps/balls between the chips and the TSV interposer, the TSV interposer and the organic package substrate, and the package substrate and the PCB (printed circuit board) under environmental thermal cycling condition.