Effect of TSV Joule Heating on Device Performance

Convergence and miniaturization of consumer electronic products such as cameras, phones, etc. has been driven by enhanced performance and reduced microelectronics size. For past few decades Moore’s law has been driving the microelectronics industry to achieve high performance with small form-factors at a reasonable cost. While the continued miniaturization of the transistors has resulted in unparalleled growth of the electronics industry, further performance increment via size scaling could be cost-ineffective and difficult to manufacture. To satisfy the current/future integrated Circuit (IC) package requirements, vertical integration of chips holds the key, i.e., 3-D packaging. Chip-stacking (3-D) is emerging as a powerful technology to reduce package footprint, decrease interconnection power, higher frequencies, and provide efficient integration of heterogeneous devices. It allows further reduction in the form factor of current systems and eases the interconnect performance limitation since the components are integrated on top of each other instead of side-by-side, resulting in shorter interconnect lengths. Due to high package density and chip-stacking on top of each other, heat dissipation from the stacked chips becomes a concern. To overcome these thermal challenges and provide shorter/faster inter-chip electrical connection, Through Silicon Via (TSV) technology is being implemented in 3-D ICs. TSVs allow 3-D chips to be interconnected directly and provide high speed signal propagation. TSVs provide inter-chip heat/current path but the current flowing through the TSVs results in localized heat generation (Joule Heating) within the silicon, which could be detrimental to the overall performance of the system. In this paper, the effect of Joule heating on the device performance measured by trans-conductance, electron mobility (e− mobility), and channel thermal noise is analyzed. Thinned (100 μm) chips with a uniform power map and evenly distributed TSVs are analyzed in this work. Thermal distribution in the package is studied for different TSV currents including a base-line case of no-current (thermal TSV only) and the junction temperature is determined for each case. The response from the thermal analysis is correlated to the device performance through existing relations. Results indicate that joule heating has a significant effect on the thermal response of the 3D IC and subsequently proves to be detrimental to the chip performance. An understanding of the electrical performance dependence on TSV joule heating is developed through this work.