Realization Of Sub-30-Pitch EUV Lithography Through The Application Of Functional Spin-On Glass

Patterning performance strongly depends on resist/underlayer adhesion. With the appropriate resist/underlayer adhesion, one can realize 28-nm pitch printing with defect-free depth of focus larger than 300 nm and unbiased line-width roughness around 2.2 nm.

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Photoresist metrics such as resolution, roughness, CD uniformity, and overall process window are often aimed to realize the full potential of EUV lithography. From the view of the materials supplier, improvements over the aforementioned metrics can be achieved by optimizing the functional materials used under the resist. The underlayers can significantly enhance the resist performance by providing appropriate adhesive forces to the patterned features, counterbalancing the tendency of pattern collapse, and improving the resist/substrate compatibility. In this study, we introduce spin-on-glass (SOG) underlayers that can provide adhesion to resist through different mechanisms, including covalent bonding, hydrogen bonding, and Van der Waals force. The underlayers were characterized in depth to understand their coating quality, adhesion to resist, and surface energy. The EUV lithographic performance was evaluated by applying chemically amplified resists (CARs) directly onto these SOGs for line/space features at the target pitch sizes of 30 nm and 28 nm. The lithographic evaluation indicates that the patterning performance strongly depends on resist/underlayer adhesion. By appropriately adjusting the resist/underlayer adhesion, we can realize 28 nm pitch printing with defect-free depth of focus larger than 300 nm and unbiased line-width roughness around 2.2 nm. The plasma etch rate of the SOGs were also evaluated to assess their pattern transfer performance.

Authors: Yichen Liang,1 Kelsey E. Brakensiek,1 Joyce Lowes,1 Andrea M. Chacko,1 Ruimeng Zhang,1 Veerle Van Driessche,1 Xiaolong Lang,1 Jaishankar Kasthuri,1 Ming Luo,1 Douglas J. Guerrero1

1Brewer Science, Inc. (United States)

Proceedings Volume 12055, Advances in Patterning Materials and Processes XXXIX; 120550A (2022) https://doi.org/10.1117/12.2610985
Event: SPIE Advanced Lithography + Patterning, 2022, San Jose, California, United States

Click here to view entry on SPIE Digital Library (presentation and paper).



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