Professor Kim Tae-gon of Hanyang University was recognized at this year’s ASML Korea Tech Talk on Aug. 23 with the ‘Young Scientist Award’ for his work on developing innovative ways to decontaminate mask and pellicles in EUV technology.
Kim’s work involves how to effectively minimize or eliminate the foreign substances found sticking to EUV masks and pellicles, which refer to material for protecting the masks to reduce wafer defects when manufacturing chips.
The professor proposed a dry-type laser induced shock wave, which his experiments showed to be more effective and less damaging compared to the wet-type high frequency sound wave cleansing method.
This is because while, the conventional wet-type is more effective for eliminating nano-sized foreign substances, the method creates so-called bubble cavitation that can damage the wafer patterns.
Kim added, however, that more research needs to be done on the physical and chemical changes that can occur to masks and pellicles under the laser shock wave method.
Semiconductor chips can often become damaged due to foreign materials such as dust. But it’s hardly easy replacing masks and pellicles whenever it’s found to have been compromised by dust or other foreign materials considering that EUV masks cost 500 million won ($4.1 million) per mask, while pellicles cost around 100 million won each.
“The costs are why masks and pellicles were cleaned and recycled in the past,” said Kim. “For EUV masks and pellicles, it has actually become more difficult to clean them without causing damage.”
Further progress in Kim’s work would be effective in cutting related costs, according to experts at the ASML Tech Talk.
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