EUV Resist Process Performance Investigations on the NXE3100 Full Field Scanner

Abstract

Extreme Ultraviolet (EUV) Lithography is a candidate for device manufacturing at the 22nm half pitch node and beyond. The key challenge for EUV resists remains to simultaneously meet the requirements for Sensitivity, Resolution and Line-edge-roughness (LER) for Line/Space features (LS), respectively local CD uniformity (LCDU) for Contact holes (CH). The introduction of the ASML NXE:3100 pre-production EUV scanner at Imec, with off-axis illumination provides resolution capability well below 22nm.In this paper we make a assessment of the EUV resist performance for 22nm LS and 28-26nm contacts on the NXE:3100. At 22nm feature sizes, pattern collapse and LER become the main resolution and process windows limiters. The application of FIRM TM Extreme 10 rinse was found to be effective to improve the collapse margin and reduce LER on several resists. Using dipole illumination setting, we achieved 22nm LS at 13.5mJ/cm 2 with 3.1nm (3) LER with wide processing latitudes. Several resists resolved down to 20nm LS. Champion resolution of 19nm LS was obtained in one resist at 20mJ/cm 2 . Using quasar illumination, 28nm HP contact holes were obtained with LCDU value of 1.0nm (1) at <20mJ/cm 2 , showing wide process latitudes. Printing 26nm HP contacts is feasible but requires further improvement in LCDU and contact shape circularity.

Theoretical study of fabrication of line-and-space patterns with 7 nm quarter-pitch using electron beam lithography with chemically amplified resist processes: II. Stochastic effects

“…7) Because of this trade-off relationship, it is difficult to simultaneously meet the requirements for resolution, LER, and sensitivity. 8,9) For EUV lithography, the feasibility of sub-10-nm half-pitch fabrication has been investigated on the basis of the performance of the latest chemically amplified resists. 10) It has been reported that LER rapidly increases in the sub-10-nm half-pitch region.…”

Towards the resolution limit of Talbot lithography with compact EUV exposure tools

“…The developer is then replaced by isopropanol as a development stopper (4) and the isopropanol is evaporated on a hot plate (5). In a last step, the mask is hard baked at 100 °C to increase the radiation stability of the resist under EUV exposure (6). As a result, the electron beam resist gets more stable and can be used directly as a phaseshifting mask material.…”

“…For the qualification of next-generation photoresists in extreme ultraviolet (EUV) lithography, patterning tools and technologies are even more limited because often a resolution beyond the state-of-the-art is required. Research on the photoresists and the related processing is mostly done with high-volume manufacturing (HVM) tools 6 and at synchrotron facilities [7][8][9][10] . For photoresist development, process optimization as well as quality control, mostly dose scans and resolution tests are required.…”

Investigation of the resolution limit of Talbot lithography with compact EUV exposure tools

“…Qualifying next-generation photoresists for extreme ultraviolet (EUV) lithography presents even greater challenges, as it often demands resolutions beyond the state-of-the-art. Research on photoresists and related processing relies mostly on high-volume manufacturing (HVM) tools 6 and synchrotron facilities [7][8][9][10] . To optimize the photoresist development process and ensure quality control, sensitivity, contrast and resolution tests are necessary.…”