In Lithography the first ever parts of the hNA scanner were completed and the sensor systems matched 3nm node requirements by ASML. Zeiss SMT has delivered modules and systems of the 0.55NA EUV projection optics, i.e. the mirror modules, a mechanical representative of the POB, as well as the prototype of the POB itself. DEMCON integrated and qualified the hNA wafer stage positioning module qualification tool. IMS Chips manufactured prototype Diffractive Optical Elements (DOEs) for mirror measurements. Fraunhofer IISB tested and applied models for polychromatic effects in hNA EUV imaging. Fraunhofer IWS upscaled the polishing process and ion beam smoothing to ø ~300 mm EUV mirrors. VDL realized modules for the wafer handler systems (Figure 1).
In Metrology the partners focused on 3nm technology node metrology tools and hybrid methodologies. AMIL qualified its new Critical Dimension Scan Electron Microscope with advanced e-beam tilt and presented a hybrid CD-SEM - EDX method to extract height and SiGe concentration of underlayers of a nanosheet device using imec’s montblanc test vehicles (Figure 2). Nova qualified the new OCD interferometric channel and significantly improved the correlation of its results to a TEM reference on imec’s montblanc test wafers. FEI has completed development of an advanced new generation TEM platform, which includes novel CFEG electron source, “S-Corr” electron optical corrector, NG STEM detector unit “Panther”, and pixelated 4D electron detector “EMPAD”) and qualified it with imec’s imec ATLAS platform SuperVIA (Figure 3). KTI has completed development of overlay target design modules which enabled selection of on-product overlay targets for the 3nm technology node using imec’s LAMBIC test vehicle wafers.
In the development of EUV mask infrastructure, absorber material selection is key. Aspects covered are imaging performance, material deposition & composition, analysis & measurement of optical properties, etch-ability, repairability and cleanability. These were documented for a selected set of promising materials, based on experimental assessment and guidance on imaging performance by simulation. Second is reticle life time, with in-situ XPS the impact of storage was studied. For both topics, actinic (EUV) – and X-ray metrology have been instrumental. Further achievements are: preparation of anamorphic and isomorphic mix-and-match imaging and overlay tuning to reduce scanner-non-correctable overlay errors, realization of focused e-beam induced deposition technology for repair of phase shift masks and demonstration of resolution improvement in actinic patterned mask inspection based on lensless imaging.
Regarding process and module solutions for 3nm node, advances in the 3rd period include: finalisation of design rules, demonstration of eSALELE patterning at 21nm pitch (Figure 4), computational lithography solutions for hNA lithography. FEOL module development yielded: low-k gate spacer integration, contact resistivity reduction via in-situ doped S/D and heavy metal silicides, innovative gap fill solutions, further reduction of Treading Defect Dislocations for SiGe strain relaxed buffers, damage free rinsing/drying processes for high aspect ratio structures. Regarding module build for MOL, demonstrate low resistive, void free Ru-based metallization for contacts. For 3nm node BEOL, hybrid metallization: electrical results for Ru-Ru-Cu metallization, proof of concept for Cu-Ru-Cu and Cu-W-Cu hybrid metallization. Electrical results for Thin Film Transistors in BEOL, electrical results for Super Via scaling booster (Figure 5).
