3D Heterogeneous Integration with Sub-3μm Bond Pitch Chip-to-Wafer Hybrid Bonding

3D heterogeneous integration has become increasingly important as it allows continued package system scaling in combination with transistor scaling to increase density and performance. As solder-based interconnect reaches its pitch scaling limit around 10μm, hybrid bonding interconnect (HBI) is the next generation interconnect technology to continue the pitch scaling journey beyond 10μm. HBI offers unique capabilities that enable ultra-high interconnect density and bandwidth, low interconnect power consumption and latency, and various new 3D packaging architectures. The benefit of having HBI is crucial for future AI and high performance computing (HPC) systems.In this paper, we present a systematic study of chip-to-wafer hybrid bonding (C2W HB) down to 3μm pitch and below. Starting with the discussion about challenges for the placement accuracy requirement with symmetric pad design to enable sub-3μm pitch chip-to-wafer HBI. We show excellent bonding quality, electrical yield and reliability are achieved with comprehensive optimization between design, process control and tool/material development. Finally, we cover 3D heterogeneous integration architectures with C2W HB.