It’s generally said that the management of particles is important. In DUV lithography, it’s needed to remove particles on photomask surface not to induce patterning defects on wafer. Moreover, in Nanoimprint lithography (NIL), particles on template cause not only patterning defects on wafer but also its own pattern collapse. Therefore, these particles have to be entirely removed from substrate surface with cleaning technology. In this paper, we proposed ‘Freeze Cleaning’ which has more than 99% PRE for 40nm SiN standard nanoparticle without pattern collapse and critical dimension (CD) shift. And it was also demonstrated that soft defects on template which remained after conv. cleaning could be removed with Freeze Cleaning. These results predict that Freeze Cleaning will contribute to progress of photomask and template technology to next stage.
|