# [2405.11717] Can we improve the energy efficiency of EUV lithography?

Source: https://arxiv.org/abs/2405.11717
Kiwi News: https://news.kiwistand.com/stories/240511717-Can-we-improve-the-energy-efficiency-of-EUV-lithography?index=0x66b2619f18b94f4de6204e79ee0d5c771848d4e7a6731cc9aef538f8b1a40e5aecb3c8e3
Submitted by m-j-r.eth on 2024-08-06 UTC, 1 upvote, 0 comments

## Summary

A preprint by Tsumoru Shintake proposes a simple, low-cost two-mirror EUV projector that would cut the required EUV source power by a factor of 10 compared with current six-mirror EUV projectors. The paper states that the design needs 20 watts of EUV power for a process speed of 100 wafers per hour. It describes a cylindrical tube configuration similar to a DUV projector, with a theoretical resolution limit of 24 nm over a 20 mm field at 0.2 NA and 16 nm over a 10 mm field at 0.3 NA, using a curved-surface mask to reduce tool height.

## Article

Can we improve the energy efficiency of EUV lithography?

Authors: Tsumoru Shintake

This paper discusses a simple, low-cost, highly efficient two-mirror projector with a simplified illumination system. The EUV source power can be reduced by 1/10 compared to the current six-mirror EUV projector system. The required EUV power is 20 watts for process speed of 100 wafers per hour. The proposed in-line projector achieves 0.2 NA (20 mm field) and 0.3 NA (10 mm field), which can be assembled in a cylindrical tube configuration similar to a DUV projector, providing superior mechanical stability and easier assembly/maintenance. The EUV light is introduced in front of the mask through two narrow cylindrical mirrors located on both side of the diffraction cone, providing average normal illumination and reducing the mask 3D effect. The simplified illumination system provides symmetric quadrupole off-axis illumination, bypassing central obscuration and improving spatial resolution, also realizing Köhler illumination. The theoretical resolution limit is 24 nm (20 mm field), image reduction factor x5 and object image distance (OID) 2000 mm. With the curved surface mask, the tool height can be reduced to (OID) 1500 mm, which provides resolution 16 nm (10 mm field). It will be suitable for small die size chip production for mobile applications as well as the latest chiplet technology.