Throughput Increases Using EUV Assist Layers

• Published in: ECS transactions Vol. 44; no. 1; pp. 215 - 218
• Main Authors: Washburn, Carlton, Ouattara, Tantiboro, Collin, Aline, Krishnamurthy, Vandana, Guerrero, Douglas
• Format: Journal Article
• Language: English
• Published: The Electrochemical Society, Inc 16.03.2012
• ISSN: 1938-5862; 1938-6737
• DOI: 10.1149/1.3694319

Extreme ultraviolet (EUV) exposure is among the front-runners for single-exposure lithography for the 16-nm node and below. One major issue moving toward production is the source power for EUV, which dictates the throughput of the EUV exposure tools. Source suppliers are working to increase the source power as a possible solution. Another approach to limited source power is to use the available photons more efficiently. Previous work has shown that assist layers are critical for performing EUV lithography. Assist layers enhance the adhesion of EUV photoresists, block substrate contamination, and improve the resolution, line width roughness, and sensitivity (RLS) tradeoff. Recent research has also shown that assist layers can enhance the dose to size of a photoresist. This amplification allows the same features to be produced with a smaller exposure dose, which increases throughput. In this paper, we report the study of new assist layers with novel resins that show superior lithography performance. The results will show how to significantly improve lithography throughput by reducing the dose to size, while monitoring the trade-off often seen with line roughness and exploring the exposure latitude and depth of focus of the process.