By Josh Perry, Editor
Researchers at Carnegie Mellon University (Pittsburgh, Pa.) and the National Renewable Energy Laboratory (NREL) have created a new material that can fill the role of conventional solders but with twice the thermal conductivity of current thermal interface materials (TIM).
Associate Professor Sheng Shen and his Ph.D. candidate Wei Gong.
(Carnegie Mellon University College of Engineering)
This supersolder, according to a report from the university, breaks through the current bottleneck in soldering materials, which had reached the limit of their ability to dissipate heat effectively over a long period of time.
To enhance its thermal properties, researchers incorporated copper-tin nanowire arrays into the material. According to associate professor Sheng Shen, the lead researcher on the project, the nanowires are grown one layer at a time from a template.
“Supersolder also exhibits extraordinary compliance, or elasticity, on par with that of rubber or other polymers,” the article explained. “This is important, as the parts that the solder connects expand and contract when heated, often at varying rates between two parts of differing composition.”
In an experiment, a conventional solder assembly of tin declined in thermal performance after less than 300 hours of cycling, while the supersolder was at peak performance for more than 600 hours. The actual limit to its performance is still unknown because it lasted so long (and the researchers had to stop so a paper could be published).
“Supersolder could replace conventional solder in electronic systems ranging from micro- and portable electronics to warehouse-sized data centers, reducing temperatures to enable significant improvements in power density and reliability,” the article continued. “Anything conventional solder can do, supersolder can do better—almost.”
Researchers will continue working on the material to remove its electrical conductivity, while retaining its thermal properties.
The research was recently published in Nano Letters. The abstract stated:
“Due to the substantial increase in power density, thermal interface resistance that can constitute more than 50% of the total thermal resistance has generally become a bottleneck for thermal management in electronics. However, conventional thermal interface materials (TIMs) such as solder, epoxy, gel, and grease cannot fulfill the requirements of electronics for high-power and long-term operation.
“Here, we demonstrate a high-performance TIM consisting of a heterogeneous copper–tin nanowire array, which we term ‘supersolder’ to emulate the role of conventional solders in bonding various surfaces. The supersolder is ultracompliant with a shear modulus 2–3 orders of magnitude lower than traditional solders and can reduce the thermal resistance by two times as compared with the state-of-the-art TIMs.
“This supersolder also exhibits excellent long-term reliability with >1200 thermal cycles over a wide temperature range. By resolving this critical thermal bottleneck, the supersolder enables electronic systems, ranging from microelectronics and portable electronics to massive data centers, to operate at lower temperatures with higher power density and reliability.”
Learn more about Prof. Shen’s work with polymer nanofibers in the video below: