Engineering professor receives award for ALD research

Dr. Chris Yingchun Yuan, an associate professor of mechanical and aerospace engineering at Case Western Reserve University, recently received the first place award in the Reusable Abstractions of Manufacturing Processes competition facilitated by the National Institute of Standards and Technology, the National Science Foundation, the American Society of Testing and the Materials and the American Society of Manufacturing Engineers. Evaluated on the research model’s complexity, clarity, accuracy, novelty and presentation, Yuan’s solution regarding “Sustainable Manufacturing Analysis of Atomic Layer Deposition of Al2O3 Thin Film” fit the bill.

According to Beneq, an ALD producer and equipment supplier, atomic layer deposition, or ALD, is a process that covers objects with a film that is only nanometers thick. ALD is integral to the development and enhancement of modern-day technologies because the film it produces can serve as an insulator in a multitude of scenarios. For instance, electronics in today’s society possess miniscule operating systems. In order to effectively insulate the parts composing these tiny systems, a tinier coating must be applied to prevent the systems from overheating (with the increasing rates of processing). So, ALD allows for the miniaturization of electronic systems while maintaining rapid processing.

Unfortunately, this method of coating materials is not conducive to reducing environmental damage and supporting sustainability.

“ALD uses toxic chemicals for processing reactions, and most toxic chemicals input into the ALD process are being wasted as environmental emissions,” Yuan said.

Yuan noticed during his PhD at the University of California, Berkeley, that a large proportion of precursor materials used in the ALD process were being wasted and that nobody had studied the mechanism of waste generations or the potential environmental impacts of ALD technology before. (According to Beneq, precursor materials are the chemical gases that are utilized in ALD to form the resultant film that coats the object.) As a result, he began his research on sustainability as it related to the ALD process.

“Aluminum oxide is the most commonly studied material for the ALD process [when creating films to coat other materials],” Yuan said.

Just as E. coli is utilized for many biological research abstracts, aluminum oxide is utilized as the case study for ALD technology. As a result, aluminum oxide was utilized for Yuan’s research, since it is considered the model process.

“The most challenging problem was determining the real-time distributions and dynamic flows of ALD precursor materials under various operating conditions,” Yuan said.

For Yuan, the most rewarding part of his research was the discovery from this research of the systematic understanding of the ALD process emissions and waste generation mechanism, to support future research and development of ALD technology.

Ultimately, Yuan hopes that the research could be implemented in future ALD technology development to minimize the ALD process wastes and emissions, which would reduce both economic costs and environmental impacts of ALD operations.

Overall, conducting this research on sustainability of the ALD process as it relates to creating an aluminum oxide film required ten years of research by Yuan.