Compatibility assessment of novel reticle absorber materials for use in EUV lithography systems
de Rooij-Lohmann, V.I.T.A.
van Schaik, W.
Goldberg, K.A. (editor)
Novel absorber materials are being developed to improve EUV-reticle imaging performance for the next generations of EUV lithography tools. TNO, together with ASML, has developed a compatibility assessment for novel absorber materials, which addresses the risk that exposure of incompatible materials to EUV-radiation and EUV-plasma conditions results in contamination of the optics in the EUV lithography tools. The assessment is divided in two stages to optimize the efficiency of the procedure. Most contamination risks can be addressed cost-efficiently in the first stage with existing vacuum and plasma test facilities. Novel absorber materials can thus be assessed in an early stage of their development without the immediate need for more expensive EUV testing. This stage of the compatibility assessment was executed with an EUV reticle piece with a TaN-based absorber, and results are presented. The TaN-based absorber showed no compatibility issues, as expected. This test procedure now sets the baseline for testing novel absorber materials. 96.000 exposures can be performed in a NXE 3400 EUV lithography tool with a 300W source with absorber materials that successfully passed the first stage of the compatibility assessment. Assuming 96 exposures per wafer, this equals 1000 wafers. Absorber materials that passed the first stage may proceed to the second stage: An accelerated EUV test exposure in the EUV Beamline 2 (EBL2). Each material will be exposed to an EUV-dose equivalent to about half a year of reticle exposure in the NXE 3400 lithography tool with a 300W source. This test is in preparation and expected to be available in the second quarter of 2019.
High Tech Systems & Materials
To reference this document use:
Accelerated lifetime test
Plasma surface interaction
Proceedings Extreme Ultraviolet (EUV) Lithography X 2019, 25-28 February 2019, San Jose, CA, USA