Posted: July 13, 2010

EUV mask cleaning program on track towards EUV mass manufacturing

(Nanowerk News) IMEC today reports promising results in its Extreme Ultraviolet Lithography (EUV) mask cleaning program for defect-free EUV masks which are crucial in achieving high chip manufacturing yield. The research program was initiated in collaboration with mask cleaning experts of HamaTech APE GmbH & Co. KG., a fully owned subsidiary of Süss MicroTec AG, and some of imec's core partners.
The objective of the dedicated EUV mask cleaning program is to develop processes of record (POR's) for EUV mask cleaning that not only are effective in removing particles and organic contamination without damage to the vulnerable materials of the EUV masks, but do not reduce mask lifetime through repetitive cleaning. A specific EUV reticle back-side cleaning process is being developed, to protect the electrostatic reticle chuck of the EUV scanner from degraded performance which can negatively affect the "print on wafer" results. Project completion is targeted for the end of 2010.
Research started after successful installation of HamaTech's state-of-the-art MaskTrack Pro® photomask processing system at the imec 300mm cleanroom in early 2010, located close to the ASML EUV Alpha demo tool. A unique combination of physical and chemical cleaning technologies have demonstrated a highly-effective removal of organic and inorganic contamination without any negative effects on mask integrity. The vulnerable absorber and capping layer of the reticle presented no significant signs of deterioration.
Kurt Ronse, program director advanced lithography at imec said, "Defect-free EUV mask availability, for achieving high chip manufacturing yield, has become one of the major concerns for EUV lithography to become a manufacturable technology, taking over from 193nm immersion. Besides the lack of EUV mask inspection infrastructure and the difficulties to make defect free EUV masks, we experience day by day how vulnerable pellicle-less EUV masks are in the wafer fab, when moved from storage to the exposure tool and back. Until standardized EUV reticle handling procedures can demonstrate not to add contamination to EUV mask during its normal lifetime in the fab, the availability of an in-fab effective cleaning process is crucial. With the results obtained so far, we are confident that it is possible to develop effective front- and back-side cleaning processes without risks to jeopardize the mask integrity after multiple repeated cleans."
"We are very pleased to collaborate with imec and its leading-edge industry partners on critical mask cleaning technology for next generation lithography processes," said Wilma Koolen-Hermkens, CEO of HamaTech APE. "MaskTrack Pro is the first proven platform in the industry that can address EUVL zero tolerance levels for particles and defects on the mask prior to exposure. With a world-class design, the MaskTrack Pro allows clustering of metrology systems and pod-in-pod stocking for a holistic mask management approach throughout the life of the mask. Imec is our partner of choice to jointly develop the necessary POR's for our valued customers."
About HamaTech's MaskTrack Pro® photomask processing system
The MaskTrack Pro platform, offers innovative cleaning, post-exposure bake and develop technology for a sophisticated mask integrity system focused on 193i 22nm hp double patterning, EUV and nano-imprint lithography technologies. MaskTrack Pro BD combines a unique ASonicTM develop technology with unmatched bake techniques for extreme pattern fidelity and perfect critical dimension (CD) uniformity matching, whereas MaskTrack Pro Clean ensures that the mask is defect-free at point-of-exposure, offering customers a dramatic increase in exposure tool availability and uptime.
About imec
Imec performs world-leading research in nanoelectronics. Imec leverages its scientific knowledge with the innovative power of its global partnerships in ICT, healthcare and energy. Imec delivers industry-relevant technology solutions. In a unique high-tech environment, its international top talent is committed to providing the building blocks for a better life in a sustainable society. Imec is headquartered in Leuven, Belgium, and has offices in Belgium, the Netherlands, Taiwan, US, China and Japan. Its staff of more than 1,750 people includes over 550 industrial residents and guest researchers.
Source: imec