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Proceedings Paper

Photobase generator assisted pitch division
Author(s): Xinyu Gu; Christopher M. Bates; Younjin Cho; Takanori Kawakami; Tomoki Nagai; Toshiyuki Ogata; Arunkumar K. Sundaresan; Nicholas J. Turro; Robert Bristol; Paul Zimmerman; C. Grant Willson
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Paper Abstract

The drive to sustain the improvements in productivity that derive from following Moore's law has led the semiconductor industry to explore new technologies that enable production of smaller and smaller features on semiconductor device. Pitch division techniques and double exposure lithography are approaches that print features beyond the fundamental resolution limit of state-of-art lenses by modifying the lithographic process. This paper presents a new technique that enables pitch division in the printing of gratings using only a single exposure that is fully compatible with the current manufacturing tools. This technique employs a classical photoresist polymer together with a photoactive system that incorporates both a photoacid generator (PAG) and a photobase generator (PBG). The PBG is added to the resist formulation in higher molar concentration than the PAG, but has a base production rate that is slower than the acid production rate of the PAG. The PBG functions as a dose-dependent base quencher, which neutralizes the acid in high dose exposure regions but not in the low dose regions. This photoactive system can be exploited in the design of both positive tone and negative tone resist formulations that provide a developed image of a grating that is twice the frequency of the grating on the mask. A simulation of this process was performed for a 52 nm line and space pattern using PROLITH and customized codes. The results showed generation of a 26 nm half pitch relief image after development. Through this new technique, a 45 nm half pitch line and space pattern was experimentally achieved with a mask that produces a 90 nm half pitch aerial image. This corresponds to a k1 factor of 0.13. The principles, the materials design and the first lithographic evaluations of this system are reported.

Paper Details

Date Published: 25 March 2010
PDF: 12 pages
Proc. SPIE 7639, Advances in Resist Materials and Processing Technology XXVII, 763906 (25 March 2010); doi: 10.1117/12.846395
Show Author Affiliations
Xinyu Gu, The Univ. of Texas at Austin (United States)
Christopher M. Bates, The Univ. of Texas at Austin (United States)
Younjin Cho, The Univ. of Texas at Austin (United States)
Takanori Kawakami, The Univ. of Texas at Austin (United States)
Tomoki Nagai, The Univ. of Texas at Austin (United States)
Toshiyuki Ogata, The Univ. of Texas at Austin (United States)
Arunkumar K. Sundaresan, Columbia Univ. (United States)
Nicholas J. Turro, Columbia Univ. (United States)
Robert Bristol, Intel Corp. (United States)
Paul Zimmerman, SEMATECH Inc. (United States)
C. Grant Willson, The Univ. of Texas at Austin (United States)

Published in SPIE Proceedings Vol. 7639:
Advances in Resist Materials and Processing Technology XXVII
Robert D. Allen, Editor(s)

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