The extreme ultraviolet lithography (EUVL) program at IMEC is aimed to tackle many unsolved critical issues of EUV lithography as the technology moves towards production, by focusing specifically on tool, resist, and mask projects. Here, the authors describe the structure of the IMEC EUVL program and the status of the EUV alpha demo tool. In particular, they discuss their proposed strategies for flare mitigation and shadowing effect correction. They demonstrate how it is possible to implement an effective rule-based flare mitigation strategy. In addition, they propose a relatively simple methodology to fully compensate for shadowing pattern placement error and critical dimension bias.

Articles you may be interested inMetrology development for extreme ultraviolet lithography: Flare and out-of-band qualification J. Vac. Sci. Technol. B 29, 06F505 (2011); 10.1116/1.3660385 Flare-variation compensation for 32 nm line and space pattern for device manufacturing on extreme-ultraviolet lithography J.

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We demonstrate electrically functional 0.099μm 2 6T-SRAM cells using full-field EUV lithography for contact and M1 levels. This enables formation of dense arrays without requiring any OPC/RET, while exhibiting substantial process latitudes & potential lower cost of ownership (single-patterning). Key enablers include: 1) highk/metal gate FinFETs with L g~4 0nm, 12-17nm wide Fins, and cell β ratio~1.3; 2) option for using an extension-less approach, advantageous for reducing complexity with 2 less I/I photos, and for enabling a better quality, defect-free growth of Si-epitaxial raised S/D; 3) use of double thin-spacers and ultra-thin silicide; 4) optimized W metallization for filling high aspect-ratio, ≥30nm-wide contacts. SRAM cell with SNM>10%V DD down to 0.4V, and healthy electrical characteristics for the cell transistors [SS~80mV/dec, DIBL~50-80mV/V, and V Tlin ≤0.2V (PMOS), V Tlin~0 .36V (NMOS)] are reported.

The EUV program at imec aims at identifying the critical issues to prepare EUV lithography for insertion into high volume IC production. The program started in 2006 with the 0.25 NA ASML Alpha Demo Tool and has since then evolved around several focus areas. 1) scanner performance, reliability and monitoring, 2) definition and verification of OPC strategies for generic and EUV specific imaging effects 3) reticle defectivity, focusing on multi-layer defects, reticle handling and reticle cleaning, 4) resist screening, focusing on identification of materials that not only simultaneously give optimal performance in terms of resolution, line width roughness and sensitivity, but that also allow adequate transfer of the EUV-fabricated patterns into the underlying layers and 5) implementation of EUV lithography into fabrication of representative device structures. Since 2011 The Alpha Demo Tool has been replaced by the ASML NXE:3100, allowing higher resolution and productivity. In this paper, selected highlights in the latest achievements of the imec EUV program will be discussed.