Co-Packaged Optics – 3D Heterogeneous Integration of Photonic IC and Electronic IC

https://www.youtube.com/watch?v=7t-ku1LJb_U

Summary

TL;DR — This lecture discusses co-packaged optics (CPO), a technology that integrates photonic integrated circuits (PICs) and electronic integrated circuits (EICs) onto a single substrate for high-performance computing and data centers. It explores various 3D heterogeneous integration methods, focusing on advancements beyond traditional on-board optics and near-package optics, and highlights the challenges and opportunities in scaling these technologies, particularly with the emergence of glass substrates.

Key points

• Co-packaged optics (CPO) involves integrating PICs and EICs on the same substrate to improve electrical performance, reduce power consumption, and enhance signal integrity, primarily for data centers and high-performance computing.

• The evolution of optical integration has moved from pluggable transceivers to on-board optics, near-package optics, and finally to CPO, where PICs and EICs are placed side-by-side on the same substrate as the main ASIC.

• Various 3D heterogeneous integration techniques are presented, including stacking EICs on PICs, using micro-bumps, through-silicon vias (TSVs), and copper-to-copper hybrid bonding to connect these components.

• The industry is exploring new substrate materials like glass to overcome the limitations of organic substrates, especially for high-transistor-count applications, though challenges remain in thermal expansion mismatch and reliability.

• Key challenges include managing thermal expansion differences between materials (like glass and silicon) and ensuring the reliability of interconnects such as C4 bumps, with ongoing research into advanced bonding techniques and materials.

• Future opportunities lie in thermal management for 3D integrated systems and developing novel interconnect solutions to enhance performance and reliability.

Takeaway — Co-packaged optics, enabled by advanced 3D heterogeneous integration techniques and new materials like glass, is crucial for meeting the increasing demands of data centers and high-performance computing by bringing optical and electronic components closer together.