Perennial push-outs of EUV lithography and continued reliance on 193nm immersion technology have opened the way for technologies to supplement inherent challenges for both. Not only is E-beam lithography gaining attention again but imec believes a ‘Directed Self-Assembly’ process not only has the potential to tackle small feature formation but provide a low-cost approach, lacking in the pursuit of ever-decreasing feature sizes.
Kicking of the SPIE Advanced Lithography conference, imec said it had established the world first 300mm fab-compatible Directed Self-Assembly (DSA) process line at its 300mm R&D facility in Leuven, Belgium.
The R&D centre collaborated with the University of Wisconsin, AZ Electronic Materials and Tokyo Electron Ltd. TEL provided a dedicated and specially configured DSA coater/developer with installed DSA materials in gallon-size quantities. A metrology toolkit including DSA defect inspection, and in-house pattern transfer capabilities has also been installed.
According to imec, DSA is an alternative patterning technology that enables frequency multiplication through the use of block copolymers. A pre-pattern is first used that directs the orientation for patterning. DSA is said to reduce the pitch of the final printed structure as well as be used to repair defects and repair uniformity in the original print.
Imec noted that with EUV lithography, local variation in the CD (critical dimension), especially in case of small contacts is common, therefore uniformity repair by DSA could be a significant supporting process in production environments, once EUV becomes introduced.
“We are excited with this achievement, as this enables us to expand the scope of our research offering and toolset bringing more value to our partners,” commented Kurt Ronse, Director Lithography Department at imec. “The availability of a DSA processing line enables us to further push the limits of 193nm immersion lithography and overcome some of the critical concerns for EUV lithography. This allows us to further push the limits of Moore’s law.”
"With this process, imec has taken an important step towards fulfilling the low cost, high resolution promise of bottom up DSA lithography," added Ralph Dammel, CTO of AZ Electronic Materials. "We are committed to providing the high performance materials the industry needs to make DSA a commercial reality."
Imec noted that work on DSA was now part of its Advanced lithography program, in its core CMOS programs that includes Globalfoundries, Intel, Micron, Panasonic, Samsung, TSMC, Elpida, Hynix, Fujitsu and Sony.
“Our work together results in unprecedented integration of DSA with manufacturing-ready tools and materials, allows investigation of the ultimate potential and possible limits of DSA not possible in an academic setting, and provides exceptional educational opportunities for our students. We are gratified to be on a pathway with imec towards commercialization of technology we have spent almost 15 years developing,” noted Prof. Paul Nealey of the University of Wisconsin.
Caption: 14nm polystyrene lines on 28nm pitch after PMMA removal fabricated by DSA using 193nm immersion based 84nm pitch pre-pattern
(left) and demonstration of the ability to repair a 200nm gap in the pre-pattern (right).