12 March 2019 Super-resolved critical dimensions in far-field I-line photolithography
Author Affiliations +
Funded by: NSF MRSEC, Sandia National Laboratories, National Nuclear Security Administration
Abstract

Background: Resolution enhancement combined with multiple patterning enables photolithography to write patterns with both feature size and spacing below the diffraction limit. Continued resolution enhancement at i-line will enable an older generation of lithographic tools to reach resolutions typically achieved using deep UV (DUV).

Aim: A demonstration and deterministic model of large critical dimension enhancement at i-line. In addition to enhanced resolution, the technique must also achieve high repeatability and low line edge roughness (LER), while using commercial resists.

Approach: Overexposing photoresist with high-contrast interference nulls leads to subwavelength critical dimensions. Starting with a theoretical analysis of the technique, we consider limits imposed by optics, linewidth scaling rates, and LER. This analysis shows that low LER and deterministic linewidth control are both readily achievable.

Results: We demonstrate large area, i-line patterning of features with 50-nm linewidth, without the aid of subsequent trim or etch and with LER of 5 nm. Linewidth is shown to scale with dose as predicted from the optical model, independent of photoresist.

Conclusions: These dimensions are similar to what may be achieved using scanning near-field, DUV, or e-beam lithography, yet achieved with far-field near UV exposures over a large area. Deterministic linewidth control and low LER make this process viable for fabrication at length scales well below those typically achieved with i-line tools.

© 2019 Society of Photo-Optical Instrumentation Engineers (SPIE) 1932-5150/2019/$25.00 © 2019 SPIE
David B. Miller, Darren L. Forman, Adam M. Jones, and Robert R. McLeod "Super-resolved critical dimensions in far-field I-line photolithography," Journal of Micro/Nanolithography, MEMS, and MOEMS 18(1), 013505 (12 March 2019). https://doi.org/10.1117/1.JMM.18.1.013505
Received: 14 October 2018; Accepted: 19 February 2019; Published: 12 March 2019
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CITATIONS
Cited by 9 scholarly publications.
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KEYWORDS
Photoresist materials

Line edge roughness

Optical lithography

Lithography

Diffraction

Nanoimprint lithography

Photoresist developing

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