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Proceedings Paper

Direct comparison of the performance of commonly used e-beam resists during nano-scale plasma etching of Si, SiO2, and Cr
Author(s): Andy Goodyear; Monika Boettcher; Ines Stolberg; Mike Cooke
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Paper Abstract

Electron beam writing remains one of the reference pattern generation techniques, and plasma etching continues to underpin pattern transfer. We report a systematic study of the plasma etch resistance of several e-beam resists, both negative and positive as well as classical and Chemically Amplified Resists: HSQ[1,2] (Dow Corning), PMMA[3] (Allresist GmbH), AR-P6200 (Allresist GmbH), ZEP520 (Zeon Corporation), CAN028 (TOK), CAP164 (TOK), and an additional pCAR (non-disclosed provider). Their behaviour under plasma exposure to various nano-scale plasma etch chemistries was examined (SF6/C4F8 ICP silicon etch, CHF3/Ar RIE SiO2 etch, Cl2/O2 RIE and ICP chrome etch, and HBr ICP silicon etch). Samples of each resist type were etched simultaneously to provide a direct comparison of their etch resistance. Resist thicknesses (and hence resist erosion rates) were measured by spectroscopic ellipsometer in order to provide the highest accuracy for the resist comparison. Etch selectivities (substrate:mask etch rate ratio) are given, with recommendations for the optimum resist choice for each type of etch chemistry. Silicon etch profiles are also presented, along with the exposure and etch conditions to obtain the most vertical nano-scale pattern transfer. We identify one resist that gave an unusually high selectivity for chlorinated and brominated etches which could enable pattern transfer below 10nm without an additional hard mask. In this case the resist itself acts as a hard mask. We also highlight the differing effects of fluorine and bromine-based Silicon etch chemistries on resist profile evolution and hence etch fidelity.

Paper Details

Date Published: 17 March 2015
PDF: 8 pages
Proc. SPIE 9428, Advanced Etch Technology for Nanopatterning IV, 94280V (17 March 2015); doi: 10.1117/12.2085469
Show Author Affiliations
Andy Goodyear, Oxford Instruments Plasma Technology (United Kingdom)
Monika Boettcher, Vistec Electron Beam GmbH (Germany)
Ines Stolberg, Vistec Electron Beam GmbH (Germany)
Mike Cooke, Oxford Instruments Plasma Technology (United Kingdom)

Published in SPIE Proceedings Vol. 9428:
Advanced Etch Technology for Nanopatterning IV
Qinghuang Lin; Sebastian U. Engelmann; Ying Zhang, Editor(s)

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