"Forever Chemicals" Replaced in Materials Used by Semiconductor Industry
By Karen Angelo
Due to the successful efforts of a UMass Lowell research team, Transene Company, a manufacturer of advanced materials for the electronics industry, is offering etching solutions to semiconductor customers for the first time that don’t contain the toxic per- and polyfluoroalkyl substances (PFAS), harmful chemicals that do not break down over time.
“UMass Lowell faculty, students and TURI staff offer an innovative process and the resources and equipment to test the performance of various options that met the requirements of our customers,” says Transene Company President Christopher Christuk. “This collaboration accelerated our ability to manufacture and sell safer etching products, which helps companies in the electronics supply chain meet new regulatory requirements and protect health and the environment.”
Over the past several months, dozens of Transene’s customers in industries such as radio frequency and microwave chips, lasers, photronics, aerospace and defense have switched to using the new, safer etching products without PFAS.
Motivated by customer demands for PFAS-free products, Christuk turned a year ago to the Toxics Use Reduction Institute (TURI) and UMass Lowell for help. TURI awarded Plastics Engineering Prof. Ramaswamy Nagarajan a grant to fund the research project, which is now in its second year.
A class of thousands of chemicals, PFAS are often dubbed “forever chemicals” because they never fully break down in the environment. Found in a wide array of consumer and industrial products such as waterproof fabrics, food packaging, dental floss and nonstick cookware, PFAS are associated with numerous health risks, including cancer, liver damage, decreased fertility and increased risk of asthma and thyroid disease.
Like other toxic chemicals, PFAS have unique properties that can be difficult to replace. For manufacturing computer chips, PFAS allow etching materials to spread uniformly on semiconductor material surfaces.
During the first year of the project, a team of students worked together to find viable alternatives to PFAS. Rashmi Sharma ’22, who earned a Ph.D. in polymer science, and plastics engineering master’s degree student Shreyas Shelke identified safer solutions and performed experiments to compare the properties of the alternatives to PFAS. They presented data every three weeks to Christuk, Nagarajan and TURI Research Manager Greg Morose.
“As soon as we found alternatives that worked, Christopher quickly adopted the alternatives and started distributing the products to his customers,” says Sharma, who now works for Lam Research. “Finding safer alternatives is not always easy, but I enjoyed the fast-paced practical nature of an industry project.”
The students identified and tested various alternatives on surfaces such as silicon wafers, glass, aluminum and chromium. The safer etching solutions needed to meet strict criteria such as better spreading capability, enhanced surface release of gases, low-foaming characteristics, residue-free performance and preventing unwanted impurities.
“This research is a tremendous boon to students to gain experience solving real-world problems, especially replacing something as persistent and toxic as PFAS,” says Nagarajan. “We train our students to think about how solutions impact the environment and health while constantly striving for better, safer and cost-effective alternatives.”
Morose says that the challenge of finding safer solutions that work as well as PFAS for multiple applications required a collaboration between disciplines.
“The interdisciplinary research team was able to create this unique solution for industry by pooling their expertise in chemistry, engineering and public health," he says.
TURI evaluated each of the viable alternatives to ensure that the company would not be switching to another harmful solution.
“Our work with TURI was really important, because we didn’t want to be in a position of moving to something that would later be deemed a regrettable substitution,” says Christuk.
The second year of research is underway to find alternatives that meet specific criteria for more of Transene’s customers. Ph.D. plastics engineering student Mohammad Bagheri, who previously worked in the polymer plastics industry, is looking forward to collaborating with Shelke on these new challenges.
“I believe that more cooperation between industry and academia leads to more sustainability, added value and compatibility for both sides, which is why I decided to pursue my Ph.D.,” says Bagheri. “As I gain experience in working with PFAS use reduction, I would be able to consider careers that are involved with a greener and healthier world.”
For Shelke, coming up with safer options for the manufacturer was fulfilling.
“I've always been interested in green chemistry, so discovering a sustainable, nontoxic alternative to PFAS was quite exciting to me,” he says.