Performance evaluation of nonchemically amplified negative tone photoresists for e-beam and EUV lithography

• Autor(a) principal: Singh, Vikram
• Data de Publicação: 2014
• Outros Autores: Satyanarayana, Vardhineedi Sri Venkata, Batina, Nikola, Reyes, Israel Morales, Sharma, Satinder Kumar, Kessler, Felipe, Scheffer, Francine Ramos, Weibel, Daniel Eduardo, Ghosh, Subrata, Gonsalves, Kenneth E.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/116515
• topic: Litografia por feixe de elétrons; Copolímeros; Ultravioleta extrema; Polímeros; Nonchemically amplified resist; Postexposure bake; Postapply bake; E-beam lithography; Extreme ultraviolet lithography; Surface roughness; Contrast; Sensitivity; Etch resistance

Although extreme ultraviolet (EUV) lithography is being considered as one of the most promising nextgeneration lithography techniques for patterning sub-20 nm features, the development of suitable EUV resists remains one of the main challenges confronting the semiconductor industry. The goal is to achieve sub-20 nm line patterns having low line edge roughness (LER) of <1.8 nm and a sensitivity of 5 to 20 mJ∕cm². The present work demonstrates the lithographic performance of two nonchemically amplified (n-CARs) negative photoresists, MAPDST homopolymer and MAPDST-MMA copolymer, prepared from suitable monomers containing the radiation sensitive sulfonium functionality. Investigations into the effect of several process parameters are reported. These include spinning conditions to obtain film thicknesses <50 nm, baking regimes, exposure conditions, and the resulting surface topographies. The effect of these protocols on sensitivity, contrast, and resolution has been assessed for the optimization of 20 nm features and the corresponding LER/line width roughness. These n-CARs have also been found to possess high etch resistance. The etch durability of MAPDST homopolymer and MAPDST-MMA copolymer (under SF6 plasma chemistry) with respect to the silicon substrate are 7.2∶1 and 8.3∶1, respectively. This methodical investigation will provide guidance in designing new resist materials with improved efficiency for EUVL through polymer microstructure engineering.