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Inside US-JOINT’s Prototyping and Validation Line : Where Ideas Become Advanced Packages
10th July, 2026
Why establish an industry-led consortium in the United States? What is its vision? Hidenori Abe, CTO for semiconductor materials and Executive Director of Electronics Business Headquarters at Resonac Holdings Corporation, who spearheaded the project from planning to launch, shares the intent behind US-JOINT in this two-part series.
In this second article, we take a closer look at the prototype lines and evaluation facilities that support end-to-end development of advanced semiconductor packages.
Bringing Ideas to Life: An End-to-End Prototyping Line
What capabilities does the prototyping line offer?
Abe: We’ve built a line that can handle end-to-end assembly of advanced packages, primarily at the 300 mm wafer level, which is the current industry standard. It covers three key areas: fine-pitch bumping, fine redistribution wiring, and chip embedding.
For chip-to-wafer bonding, we use thermal compression bonding, including both conventional flux-based and flux-less processes. We also support integrated steps such as underfill and compression molding.
The line is further supported by lithography, plating, and sputtering for RDL formation. For embedded structures—such as bridge chips or components within interposers—we provide a process flow that covers chip placement, molding, and subsequent wiring.
US-JOINT Clean Room
What evaluation capabilities are available?
Abe: We have optical microscopes, SEM, and FIB systems to verify whether test vehicles are assembled as designed. FIB allows detailed observation of cross-sectional structures, including bonding conditions and material layering.We also provide accelerated testing under temperature and humidity stress for reliability evaluation. If failures such as cracks or delamination occur, they can be analyzed immediately.
How can customers use US-JOINT?
Abe: The key strength is that everything—from prototyping and evaluation to problem-solving—can be done in one place. We work with customers from early concept through to realization. Even when simulations look ideal, real builds often reveal gaps—warpage, imperfect interfaces, or differences in surface roughness and adhesion can all come into play. These challenges are especially pronounced in advanced packaging, where the use of organic materials with higher thermal expansion leads to stress and deformation. As a result, even well-designed concepts don’t always behave as expected in real processes.
Hidenori Abe,
CTO for semiconductor materials
and Executive Director
of Electronics Business Headquarters
Beyond Prototyping: Bridging the Gap from Verification to Mass Production.
How does US-JOINT connect to manufacturing?
Abe: Concept validation is iterative—it doesn’t end in one pass. When issues come up, customers and materials and equipment suppliers work through them together. Our goal is to compress each validation cycle—from around six months down to one.
US-JOINT itself is focused on validation, not mass production. For pilot and small-volume builds, one of our partners, Azimuth Industrial, provides that capability. Based in Union City, California, the company has been in semiconductor assembly and packaging since 1972, with a strong track record in pilot and low-volume production. Its proximity allows for a smooth handoff from validation to pilot runs. From there, customers can transition to full-scale production with foundries or OSAT providers, applying the materials, processes, and equipment developed through US-JOINT.
Driven by Business, Not Just Research: The Future Trajectory of US-JOINT
How is US-JOINT different from other consortia?
Abe: The main difference is that US-JOINT is not research-oriented, but business-driven. Many existing consortia are led by universities or government institutes and focus on research. In contrast, US-JOINT is led by Resonac and formed by private companies. It is one of the few global initiatives where materials and equipment suppliers operate prototype lines and evaluation facilities, focusing on co-creation with end users.
All participants are commercial entities and the consortium is operated with clear business objectives. That means we prioritize speed and tangible outcomes. Our benchmark is ambitious: completing concept validation in one month.
What are the key success metrics?
Abe: First, how well we meet customer expectations—across resources, quality, and speed—and whether we deliver results.
Second, partner satisfaction. If companies find real value here, the ecosystem sustains itself. US-JOINT includes 12 companies across materials and equipment sectors. Ensuring partners find value in the initiative is critical for long-term sustainability.
Our initial goal is to build a solid track record over five years in Silicon Valley, one that leads our partners to say, “Let’s keep this going.”
How will the role of consortia evolve in the semiconductor industry?
Abe: As semiconductor technologies become more complex and development cycles accelerate, it is increasingly difficult for a single company to solve advanced challenges alone. The need for co-creation will continue to grow. We hope US-JOINT will deliver concrete results and promote broader collaboration across the industry.
Finally, could you share a message with your customers?
Seeing is believing.
Abe: Once you visit, you’ll see the full line and evaluation capabilities in action, and get a real sense of how we are working to make this successful. US-JOINT is where innovation happens. If you’re interested, we’d love for you to come see it for yourself—materials and equipment suppliers are ready to work together to support your next challenge.”
Profile
CTO for semiconductor materials and Executive Director of Electronics Business Headquarters at Resonac.
Hidenori Abe leads R&D and strategy for electronic materials in semiconductors, substrates, and displays. Previously, Mr. Abe served as the head of the Electronics R&D Center and Packaging Solution Center, where he contributed to advanced packaging development through open innovation. Notably, in 2021, he directed the launch of JOINT2, a consortium targeting 2.xD and 3D packaging technologies. He also led the launch of "US-JOINT" and "JOINT3" in 2025. He received a master’s degree in chemical engineering from Tokyo Institute of Technology, Japan, and a master’s degree in the Executive MBA program from the University of Oxford, UK.
