Chemically-amplified EUV resists approaching 11 nm half-pitch

As EUV lithography moves toward high-volume manufacturing phase, one of the key factors determining the throughput and yield is the resist performance, i.e. resolution, sensitivity, and line-edge roughness. At Paul Scherrer Institute (PSI), we extensively work on EUV resist performance issues. For this purpose, we use the PSI’s EUV interference lithography (IL) tool in which a coherent beam with 13.5 nm wavelength is used to produce a well-defined periodic aerial image with virtually 100% contrast and large depth-of-focus. In this study, we report our recent results on the printability of high-resolution lines/spaces pattern down to 11 nm half-pitch (HP) with a chemically amplified resist (CAR). Although we demonstrate well-resolved 11 nm HP patterning, further improvement of the CAR’s performance in terms of pattern collapse and line-edge roughness is needed. Moreover, these results are achieved with EUV-IL tool which has a fundamentally different aerial image formation than the NXE scanner. Although EUV-IL is a powerful tool to evaluate the resist’s ultimate patterning capabilities for early optimization, what is ultimately important is the performance under manufacturing conditions, i.e. at the scanner. Therefore, we address this issue by evaluating the resist performance as a function of the contrast and resolution of the aerial image in a controlled manner, which is possible with the EUV-IL tool. In addition, we compare the performance of the state-of-the-art EUV resists using EUV-IL tool and NXE scanner and attempt to match the data obtained from EUV-IL with the performance of the NXE scanners.