TEL’s patented DCS function and conventional plasma treatment were applied on EUV PR to examine the effect of ion/radical loading and surface modification. The DCS function accelerates plasma selective deposition particularly on the top of EUV PR at 36nm pitch. The increment of EUV PR height secures etching budget and provides longer plasmas smoothing period. In addition, line roughness was also smoothed during area plasma selective deposition due to loading effect. In this study, our plasma treatment was able to improve PR roughness by 30% comparing to as-exposed litho and the performance was kept to the next oxide layer. Furthermore, an extra 13.7nm of PR was gained which enlarged the process windows of etching selectivity and plasma smoothing effect.
Extreme ultraviolet lithography (EUVL) technology is one of the leading candidates under consideration for enabling the next generation of devices, for 7nm node and beyond. As the focus shifts to driving down the 'effective' k1 factor and enabling the second generation of EUV patterning, new techniques and methods must be developed to reduce the overall defectivity, mitigate pattern collapse, and eliminate film-related defects. A typical defect Pareto for EUV line-space patterning is dominated by bridging defects and pattern collapse. Regarding pattern collapse, careful attention needs to be paid to optimizing the rinse process to avoid the large forces that cause collapse during drying. In this paper, we present an optimized rinse technology that works to prevent that pattern collapse, especially on EUV line/space patterns below 40nm pitch. Additionally, this paper reviews the ongoing progress in track-based processes (coating, developer) that are required to enable EUV patterning. This work is especially focused on defect mitigation during film coating and resist developing processes, which have a direct effect on the occurrence of bridging defects during pattern transfer.