A landmark perspective published by the National Institute of Standards and Technology's CHIPS team is drawing attention from automotive electronics suppliers grappling with polymer packaging failures in sensors and electronic control units (ECUs). The paper, issued in IEEE Transactions on Components, Packaging and Manufacturing Technology in 2025, signals that measurement gaps in polymer-based packaging materials are no longer a theoretical concern - they are a documented risk for components deployed in real vehicle environments.
Background
Polymer-based packaging materials, once viewed as little more than a means to bond or encase chips, have emerged as critical factors for reliability, performance, and cost. This shift matters acutely for automotive applications, where ECUs and sensors must endure thermal extremes, moisture ingress, and mechanical vibration across service lives measured in decades.
The NIST perspective builds on insights from a workshop, "Materials and Metrology Needs for Advanced Semiconductor Packaging Strategies," held at the 35th annual Electronics Packaging Symposium in Binghamton, NY, on September 5, 2024. It outlines challenges and opportunities related to polymer-based "soft" materials in advanced semiconductor packaging, with emphasis on polymer science, measurement science, and the strategic development of research-grade test materials (RGTMs) - efforts aimed at advancing understanding of structure-property-processing relationships and accelerating the qualification of next-generation packaging materials.
Existing automotive qualification regimes already impose demanding thresholds. ISO 16750 defines how automotive electrical and electronic components should be tested to survive real-world conditions, ensuring that parts such as sensors, ECUs, wiring, and connectors will not fail due to heat, cold, vibrations, moisture, or power fluctuations. Standards including AEC-Q100, ISO 26262, and IATF 16949 enforce temperature cycling, electrical interference, and stress tests. Yet the NIST work argues that the polymer properties underpinning those components remain insufficiently characterized before qualification testing begins.
Details
The core problem identified by NIST researchers centers on measurement gaps at the material level. Metrology challenges affecting the U.S. semiconductor industry are at a critical stage: most polymeric materials for organic laminates, underfills, epoxy molding compounds, build-up films, and adhesives are sourced overseas, and domestic manufacturers cannot readily obtain the materials data needed to engineer process flows or verify the thermomechanical properties of incoming feedstocks.
For sensor and ECU encapsulants, the failure mechanisms are well defined. During curing, thermal residual stress arises from coefficient of thermal expansion (CTE) mismatch among the materials in a semiconductor package. As packages become thinner, warpage occurs due to reduced bending stiffness caused by these residual stresses. Such warpage can damage thin silicon chips, cause cracking in the package, trigger delamination at the package-chip interface, and increase the likelihood of solder joint fracture between the package and motherboard.
NIST is developing new measurement techniques - spanning advanced rheology, spectroscopy, and stress measurement - designed to track how polymers cure, shrink, and deform during manufacturing, factors that directly affect device reliability. "Modeling without metrology is imagination," stated co-author William Chen, Chair of the IEEE's Heterogeneous Integration Roadmap for semiconductors.
NIST is also pioneering RGTMs - open, nonproprietary polymer systems that serve as benchmarks. Unlike commercial "black box" materials, these allow researchers across industry, academia, and government to compare results, improve reproducibility, and feed reliable data into computational models.
The automotive qualification overlap is direct. AEC-Q100 Revision J flip-chip ball grid array (FC-BGA) package testing protocols now simulate real-world automotive conditions with thermal cycling, moisture sensitivity, and mechanical stress tests. FC-BGA packaged components in modern automotive systems must demonstrate long-term reliability. Revision J recognizes the growing need for 14-nanometer and smaller process nodes driven by Advanced Driver Assistance Systems (ADAS). Tier 1 suppliers working with these advanced nodes will require polymer property data at a precision that existing qualification protocols have not historically demanded.
Outlook
The NIST CHIPS team aims to promote standardized guidelines and innovative methods for material characterization and to accelerate adoption of next-generation packaging materials. Insights distilled from industry panels emphasize the need for close collaboration among materials scientists, process engineers, and metrology experts, underscoring the importance of cross-sector partnerships spanning industry, academia, and government.1AEC-Q Reliability Test of Automotive IC│iST
Advances in thermal analysis, warpage and stress measurement, and modeling are expected to significantly enhance the industry's ability to design and package next-generation electronic devices. NIST intends to provide the semiconductor industry with tools and data to assess incoming feedstock properties and establish uniform test methods. For automotive sensor and ECU suppliers, the practical implication is clear: polymer characterization data generated through the RGTM framework could eventually feed directly into AEC-Q qualification submissions, potentially shortening re-qualification cycles when encapsulant materials are changed or multi-sourced.
