Dissolution performance of device pattern with low-impact development

摘要

For low-kl lithography, high accurate control of the development process is required. For that purpose, low-impact dispensing is one of the most effective approaches. In that process, development time differs between start and end position of nozzle-scan. To reduce the time lag, the nozzle-scan-speed of 140mm/s was selected. But critical dimensions (CD) offset that depends on scan-direction was detected. From the results of the CD and dissolution performances for three resists, we found that the pull-back-flow of the developer was the main cause of the CD offset. Thus, it is important that the developer dose not flow by its pull-back-force. By observing and analyzing the flow of the dissolution product with a video camera, the best condition of the scan-speed (=60 mm/s) was selected. Under this nozzle-scan condition, the dissolution rates did not depend on the scan-direction of the dispenser-nozzle. As a result, the small CD offset could be observed for 200nm L&S patterns.