New plasma technique provides cleaner surfaces in computer-chip making

A group from the Center for Plasma-Material Interactions has gained a patent on a non-contact method that uses plasma to clean very small dust and contamination particles from surfaces in the making of computer chips.

 

The technique is used to remove contamination from semiconductor wafers and the patterns used to make the chips during fabrication. Martin Neumann, NPRE adjunct faculty member and a co-developer of the process, said that even in a clean-room environment, dust and contamination becomes more of an issue, as the feature sizes of chips get ever smaller.

 

Through the newly developed technique, plasma is pulsed in such a way that it creates a charge to grow in the dust or contamination, forcing the particles off the surface being cleaned. Said Neumann, "The principle is a lot like when your hair stands up due to static electricity: the like charge build up repels the hairs from each other."

The system has a number of advantages for computer chip fabricators. It is a dry process, so no chemicals are used and nothing has to be wetted. It is non-invasive, occurring quickly, and is easily adapted into a fabrication line. It is also cost-effective.

Neumann said the process has applications beyond computer chip production. "Any application that requires non-contact methods cleaning of nanometer-sized contaminants would be appropriate," he maintains. "This has a wide range of applications within any industry working with optics and high-precision manufacturing. There may also be medical applications to this as well."

Several companies have expressed interest in the process although it has not yet been used commercially. The development team is working on test cases before licensing the patent from the University of Illinois, Neumann said.

In addition to Neumann, an NPRE alumnus (BS 99, MS 04, PhD 07), those included on the patent are David N. Ruzic, NPRE professor and Director of the Center of Plasma-Material Interactions; Brian E. Jurczyk, NPRE adjunct faculty member and alumnus (BS 95 Aerospace Engineering, MS 97, PhD 01); and NPRE alumni Darren A. Alman (BS 97, MS 01, PhD 03); and Huatan Qiu (MS 05, PhD 07). Alman works for Champaign, Illinois-based Starfire Industries, an advanced plasma technologies company Jurczyk cofounded with NPRE alumnus Robert Stubbers (MS 98, PhD 02). Qiu is a research engineer for Novellus Systems Inc. in San Jose, California.
Writer: Susan Mumm editor/alumni affairs coordinator, Department of Nuclear, Plasma, and Radiological Engineering, 217/244-5382 (campus office), 217/821-6866 (cell) 217/347-2166 (home office).