Collapse behavior of single layer 193- and 157-nm resists: use of surfactants in the rinse to realize the sub-130-nm nodes

作者：Stefan Hien, Georgia K. Rich, Gilbert Molina, Heidi B. Cao, Paul F. Nealey · 发表于：Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 年份：2002 · DOI：10.1117/12.474205 · 被引用次数：24 · 研究领域：Advancements in Photolithography Techniques、Nanofabrication and Lithography Techniques、3D IC and TSV technologies

In this study we determined the dimension dependent onset of pattern collapse for different 193 and 157nm resist platforms, and explored production relevant techniques to suppress pattern collapse. Test structures were designed and implemented to generate well-defined capillary forces on beams of resist during drying. X-ray and 193nm (using alternating phase shifting masks) lithography were used to print test structures and patterns of dense lines with critical dimensions as small as 100 nm. The collapse behavior was quantified in terms of the critical aspect ratio for collapse as a function of the spacing between structures. The resist platforms exhibited different collapse behavior at line widths of greater than 150 nm, but at line widths of 100 nm and less, all of the resist structures collapsed with aspect ratios greater than 3. A principal conclusion from this work is that changes in resist chemistry or formulation alone will not be sufficient to solve the collapse problem at the 100 nm node and below. The most effective strategy to suppress the resist collapse is to reduce the capillary forces that act on the structures during drying. For 193 nm resists, collapse behavior was quantified for a number of surfactants that were added to the rinse liquid. We demonstrate that with a simple modification of the final rinse and drying process, we could increase the critical aspect ratio from 4.2 to 5.2 at a spacing of 110 nm for a champion resist. This means, for example, that w...