28 August 2003 High-resolution etching of MoSi using electron beam patterned chemically amplified resist
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Proceedings Volume 5130, Photomask and Next-Generation Lithography Mask Technology X; (2003) https://doi.org/10.1117/12.504195
Event: Photomask and Next Generation Lithography Mask Technology X, 2003, Yokohama, Japan
High resolution etching of MoSi for photomask processing places new requirements on etching processes. As resist features are sized to 100 nm and below, it is first necessary to duplicate these features first into a chrome over-layer. After resist is stripped, this chrome over-layer is used for etching MoSi. Both chrome and MoSi etched profiles require near-vertical sidewalls, good CD (critical dimension) uniformity, good linearity, and CD mean-to-target (MTT). Additional requirements of etched MoSi include minimal roughness on exposed quartz, selectivity to chrome and quartz, phase angle target and phase angle uniformity, etch depth global uniformity, and etch depth uniformity as a function of feature size. An ETEC integrated process is used for the application of resist, patterning, and all subsequent processing. Chemically amplified resist is patterned with the 50 kV MEBES Quadra or MEBES eXara raster scan electron beam writer, allowing for patterning of small features with vertical resist profiles. Plates are etched in a Tetra photomask etch system for projecting resist images into chrome and MoSi. Etch processes have been developed specifically for etching small features in order to meet the requirements of 65 nm node lithography. An optimized etch process window is capable of patterning MoSi features below 100 nm sizes with near-vertical sidewall, < 20 nm etch bias, and with similar profile and etch bias for lines and spaces between 100 nm and > 1 um. Excellent CD uniformity and CD etch loading performance are demonstrated. Micro-profilometry is employed to measure the MoSi etch depths of features of varying sizes, and to quantify the effect of loading on MoSi etch depth. SEM micrographs illustrate sidewall profiles resulting from small feature etching.
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Mark Mueller, Mark Mueller, Serguei Komarov, Serguei Komarov, Ki-Ho Baik, Ki-Ho Baik, "High-resolution etching of MoSi using electron beam patterned chemically amplified resist", Proc. SPIE 5130, Photomask and Next-Generation Lithography Mask Technology X, (28 August 2003); doi: 10.1117/12.504195; https://doi.org/10.1117/12.504195

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