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29 March 2006 Silicon containing polymer in applications for 193 nm high NA lithography processes
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The ability to extend 193 nm lithography resolution depends on increasing the numerical aperture (NA) of the exposure system, resulting in smaller depth of focus, which subsequently requires use of thinner photoresists. Bottom antireflective coatings (BARCs) are a necessity, but the organic composition of current 193 nm BARCs offers poor etch selectivity to the photoresist. As a result, image transfer with thin resists is becoming increasingly difficult. It is also more challenging to control reflectivity at high numerical apertures with a thin, single layer BARC. To address these issues, IBM has developed a new class of silicon containing BARCs. These materials exhibit high etch selectivity that will significantly improve the performance of high NA 193 nm lithography. The incorporation of silicon in the backbone of the polymers comprising these BARCS affords a high etch selectivity to conventional organic resists and therefore these polymers can be used as thick planarizing BARCs. The optical constants of these BARCs have been tuned to provide good reflectivity control at NA > 1.2 These materials can also be used as part of a dual layer BARC scheme composed of the thin organosilicon based BARC coated over a planarizing organic underlayer. This scheme has also been optically tuned to provide reflectivity suppression at high incident angles. By utilizing a thick BARC, a novel contact hole shrink process is enabled that allows tapering of the sidewall angle and controlling the post-etch critical dimension (CD) bias. Structures of the silicon containing polymer, formulation chemistry, optical tunability, lithography at high NA and RIE pattern transfer are reported.
© (2006) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Sean Burns, Dirk Pfeiffer, Arpan Mahorowala, Karen Petrillo, Alexandera Clancy, Katherina Babich, David Medeiros, Scott Allen, Steven Holmes, Michael Crouse, Colin Brodsky, Victor Pham, Yi-Hsiung Lin, Kaushal Patel, Naftali Lustig, Allen Gabor, Christopher Sheraw, Phillip Brock, and Carl Larson "Silicon containing polymer in applications for 193 nm high NA lithography processes", Proc. SPIE 6153, Advances in Resist Technology and Processing XXIII, 61530K (29 March 2006);


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