Thermal Modeling of a Chiplet-Based Packaging With a 2.5-D Through-Silicon Via Interposer

Chiplet-based packaging technology integrates multiple heterogeneous dies with different functions and materials into a single system as a LEGO-based approach using advanced packaging technology. However, it also brings new challenges in the thermal design aspect and thermal crosstalk between chiplets. In this article, the thermal modeling of a chiplet-based packaging with a 2.5-D interposer was carried out. Two chiplets were mounted on the interposer side-by-side. A Cu lid was attached to the top surfaces of the chiplets and periphery of the interposer through the thermal interface material1 (TIM1) and adhesive, respectively. To further dissipate the heat from the top side, a heat sink was attached to the top surface of the lid through a layer of TIM2. The effects of the TIM type, bonding approach between chiplets and interposer, heat sink structure, thermal crosstalk, convective heat transfer coefficient above the lid, and thermal design power (TDP) were analyzed. The study results show that the bumpless interconnect is beneficial for the heat dissipation of the chiplet-based packaging. The staggered column fin can exhibit superior cooling performance. The short pitch would bring cooling challenges for fine-pitch multiple chiplets integration. The temperature is decreased rapidly first and then slowed down with the increase of convective heat transfer coefficient above the lid. Under 10 000 W/ $\text{m}^{2}\cdot \text{K}$ , the maximum TDP was about 250 W.