Hans-Juergen Mann

Trends in optical design of projection lenses for UV and EUV lithography

The continuing trend towards higher integration density of microelectronic circuits requires steadily decreasing feature sizes. The SIA roadmap defines the technologies needed to meet this challenges. One of the fundamental requirements for lithography with a resolution of 100 nm and below is the development of new high-performance optical designs for projection lenses.

Optics for EUV production

In 2005, Carl Zeiss SMT AG has shipped two sets of Optics for ASMLs Alpha Demo Tools. This was the starting point for the introduction of full field EUV systems. Meanwhile imaging down to 25 nm was demonstrated with the ADT tools. Based on the learning from these tools ASML has built the NXE platform - a multi-generation EUV production platform. Shipping in 2010, the NXE:3100 will be the first generation of the EUV exposure platform. We review the current status of EUV optics production for the NXE:3100 tools. Four optical systems of the 3100 series have been shipped so far. These sets of optics are characterized by significantly lower flare and wave-front levels compared to the ADT. In addition a new illumination system with higher partial coherence has been developed. In this paper we focus on mirror fabrication and at wavelength qualification results of the optical systems produced so far. We also will give an outline of the next generation, a 0.32NA exposure tool including EUVL off-axis illumination for resolutions down to 16nm. We take the expected imaging requirements as a starting point and compare it with the current status of our technology development. A brief overview for further tool extensions by higher NA will be given as well.