This paper describes the integration of a System-on-Wafer (SoW) assembly using test dielets mounted on a Silicon Interconnect Fabric (Si-IF) with an inter-dielet spacing of 100 μm and using 10 μm interconnect pitch. The continuity within and across the dielet assembly is shown using daisy chains of Au-capped Cu-Cu thermal compression bonds. The daisy chains run not only through every dielet but also across all the adjacently mounted dielets on the Si-IF. The interconnections exhibited an effective contact resistivity of 0.8-0.9 Ω-μm 2 and an average shear strength of 125 MPa. Our investigations showed that Argon plasma pre-treatment improves the shear strength of the metal bonds by a factor of 5X. Thermal simulation of the SoW assembly showed superior heat spreading across the assembly in a checkerboard configuration of alternate hot (0.5 W/mm 2) and cold (0.1 W/mm 2) dielets with an average temperature of 82 °C & 78 °C respectively.
The on-going effort of integrating heterogeneous circuits as well as the increasing length of global interconnect are driving the semiconductor community towards 3-D integrated circuits. In this work, thermal paths within a 3-D stack are investigated using the HotSpot simulator, and the results are compared to experimental data of a fabricated two layer stack with a single back metal layer. Resistive heaters and sensors measure the heat flow in both the horizontal and vertical dimensions. The dependence of the thermal conductivity on temperature is integrated into the thermal simulation process. At high temperatures (∼ 80 • C), this effect is responsible for inaccuracies in the temperature and thermal resistance of up to, respectively, 20% and 28%. As confirmed by simulation, those horizontal paths that lie mostly within the silicon layer conduct more heat as compared to the vertical paths, since the thermal conductivity of silicon dioxide is ∼ 200 times smaller than the thermal conductivity of silicon.
Carbon nanomaterials, graphene and carbon nanotubes (CNTs) have emerged as the promising materials for the integration of future advance packaging technologies. The main benefits of carbon nanomaterials include excellent electrical, thermal and mechanical properties. In this work, transfer process of a top graphene layer onto the as-grown carbon nanotube (CNT) bundles was successfully performed with direct graphene-to-CNT contact at the interface. Four-point-probe (4PP) I-V characterization suggests that an ohmic contact was achieved between the graphene and CNTs. Low CNT bump resistance of 2.1Ω for 90,000 µm 2 CNT area including the CNT/graphene contact resistance was obtained, demonstrating reduction of contact resistance between CNT and Au under the same fabrication and measurement conditions. This work presents the preliminary results for the assembly process of top-transferred graphene on CNTs and the electrical properties of direct CNT/graphene contact, paving the way for the implementation of full carbon-based three-dimensional (3D) interconnects.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.