The upcoming SMTA International Conference will feature a paper titled "Advanced Packaging for Photonics: Hybrid Bonding and Silicon Interposer Integration" presented by Dr. Charles Woychik, vice president at NHanced Semiconductors, and Dr. Navid Asadizanjani from the Florida Semiconductor Institute at the University of Florida. The paper will explore how fine-pitch copper-to-copper hybrid bonding and high-density silicon interposers enable what's known as 2.5D heterogeneous integration, meaning multiple different chiplets combined side by side on a shared substrate, for silicon photonics applications.
The presentation addresses a broader trend: as photonic systems continue scaling to support high-bandwidth applications like co-packaged optics and AI interconnects, advanced packaging techniques based on hybrid bonding and silicon interposers are becoming increasingly important to making that scaling possible. Hybrid bonding works by joining dielectric material (the insulating layer) directly to dielectric material, while also creating direct copper-to-copper electrical connections at extremely fine spacing, currently under 10 microns, with the technology expected to scale down to under 5 microns and support interconnect densities exceeding 10,000 to 100,000 connections per square millimeter. By eliminating the small solder bumps traditionally used to connect chip layers and reducing the physical height of each interconnect, this approach reduces unwanted electrical resistance and capacitance, improving signal quality and energy efficiency in high-speed connections such as those linking laser drivers to optical modulators or connecting to transimpedance amplifiers, which convert optical signals into electrical current.
Alongside hybrid bonding, silicon interposers, which include high-density redistribution layers (wiring layers with line spacing of 2 microns or less) and through-silicon vias (vertical electrical connections spaced 10 to 40 microns apart), enable 2.5D integration of different chiplet types, including silicon photonics components, onto a shared platform.
Together, these two packaging technologies enable the sub-micron alignment precision needed for low-loss optical coupling, meaning connecting optical components together with minimal signal loss, and support scalable designs that address the combined electrical, optical, and thermal constraints these systems face. The paper notes that key challenges remain, including defects that can occur during the bonding process, precise alignment accuracy, mismatched thermal expansion between different materials, and dissipating heat effectively in densely packed chip stacks, all of which require careful co-optimization of materials, manufacturing processes, and thermal management approaches. The presenters describe these advanced packaging platforms as foundational to achieving dense, energy-efficient integration of photonic and electronic components in next-generation data-centric computing systems.
The 2026 SMTA International Conference will be held at the Donald E. Stephens Convention Center in Rosemont, Illinois, from October 25-29, 2026. Organized by SMTA as part of its broader focus on electronics manufacturing technology, the conference will offer practical, research-based content covering topics including materials and process reliability, advanced packaging, AI in manufacturing, counterfeit detection, sustainability, and yield improvement strategies. Alongside its educational sessions, the conference will include an exhibition hall, technical roundtables, a keynote presentation on building a sustainable and agile culture of innovation, and networking events.
