Imec and EVG Advance Hybrid Bonding Technology for Next-Generation 3D Chip Architectures
Breakthrough at 200nm pitch supports future high-density logic and memory stacking.
IEEE Electronic Components and Technology Conference (ECTC), imec, a world-leading research and innovation hub in advanced semiconductor technologies, and EV Group (EVG), leading provider of semiconductor manufacturing equipment and process solutions, present a robust and highly yielding wafer-to-wafer hybrid bonding technology at 200nm Cu interconnect pad pitch, demonstrated on a test vehicle with routable interconnects. In addition, a record-high Cu pad alignment accuracy was achieved, leveraging EVG's most advanced wafer bonding equipment. Imec and EVG intend to further advance the wafer-to-wafer hybrid bonding roadmap, in support of logic-to-logic and memory-to-logic tier stacking use cases that require an extremely high level of interconnect density – as envisioned in imec's CMOS 2.0 scaling paradigm.
Future compute system architectures designed around imec's CMOS 2.0 scaling paradigm are driving the wafer-to-wafer hybrid bonding roadmap toward 200nm interconnect pitch. With CMOS 2.0, a system-on-chip (SoC) is partitioned into heterogeneous, functional tiers that are reconnected using 3D interconnect technologies. Depending on the application, CMOS 2.0 envisions splitting the logic part of the SoC into a high-drive logic layer and a high-density logic layer. This logic-to-logic tier stacking requires extremely high interconnect densities, which can only be offered by the most advanced wafer-to-wafer hybrid bonding technology.
Imec now demonstrates a robust wafer-to-wafer hybrid bonding technology at 200nm interconnect pitch, obtained on a test vehicle with four layers of routable interconnects pre-processed on each of the wafers before bonding. In addition, a Cu pad-to-pad post-bond overlay vector below 40nm was obtained for 100% of the dies over the full 300mm wafer – a world first. EVG's cutting-edge hybrid and fusion wafer bonding system, the GEMINI® FB, was essential for achieving this unprecedented overlay accuracy – critical for ensuring a high electrical yield.
Zsolt Tokei, imec fellow and program director of 3D system integration: "This breakthrough fine-pitch hybrid bonding result was achieved by co-optimising all the critical elements of imec's hybrid bonding process flow. These include, among others, the use of SiCN as the dielectric material (as pioneered by imec) and a chemical mechanical polishing (CMP) step before bonding. The latter was optimised for high across-wafer uniformity to produce extremely flat dielectric surfaces while achieving a controlled few nanometers of recess for the Cu pads. The high overlay accuracy and control, enabled by EVG's wafer bonding tool, were additionally facilitated by an improved Cu pad design and by pre-bond lithography corrections."
"We continue to advance our hybrid wafer bonding flow and drive the roadmap well below 200nm interconnect pitch to unlock the most demanding logic-to-logic and memory-to-logic stacking use cases," adds Zsolt Tokei. "This will require even more enhanced overlay performance, which we intend to further explore in collaboration with EVG."
"The long-standing collaboration with imec reflects the important role that wafer bonding continues to play in enabling next-generation semiconductor devices," stated Paul Lindner, executive technology director at EV Group. "Over more than three decades of working together, we have demonstrated how close collaboration between equipment suppliers and leading research organisations such as imec can drive meaningful advances in process technology. We look forward to continuing this work to support future device architectures and to strengthen collaboration across the global semiconductor ecosystem."
