Wafer Level System Integration of the Fifth Generation CoWoS®-S with High Performance Si Interposer at 2500 mm2

Chip-on-Wafer-on-Substrate with Si interposer (CoWoS-S) is a TSV-based multi-chip integration technology that is widely used in high performance computing (HPC) and artificial intelligence (AI) accelerator area due to its flexibility to accommodate multiple chips of SoC, chiplet, and 3D stacks such as high bandwidth memory (HBM). The interposer size increases steadily over the past few years, from one full reticle size (~830 mm ² ) to two reticle size (~1700 mm ² ). The growth of interposer size offers more integration power to accommodate more active silicon in a package to satisfy the HPC/AI needs. In this paper, we report the new 5 ^th generation CoWoS-S (CoWoS-S5) based on a Si interposer as large as three full reticle size (~2500 mm ² ) by a novel 2-way lithography stitching approach. This will accommodate a multiple of logic chips at a total area of 1200 mm ² (with chiplets) together with eight HBM stacks. Besides the dimensional increase of the Si interposer, new features are incorporated to further enhance the electrical and thermal performances of CoWoS-S5 compared with the previous CoWoS-S portfolio. These include an integrated deep trench capacitor (iCap) for enhanced power integrity, 5 layers of sub-micron Cu interconnect with reduced sheet resistance to satisfy high speed die to die interconnect, new TSV structure interposer for both return and insertion loss reduction, and a higher thermal conductivity thermal interface material (TIM) to achieve a lower thermal resistance. Component level reliability with excellent electrical and physical results are also discussed.