Paper
24 March 2006 ArF photo resist pattern sample preparation method using FIB without protective coating
Hirohisa Okushima, Toshihiko Onozuka, Yasushi Kuroda, Toshie Yaguchi, Kaoru Umemura, Ryuichiro Tamochi, Kenji Watanabe, Norio Hasegawa, Isao Kawata, Bart Rijpers
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Abstract
This paper presents a novel method of FIB (FIB: focused ion beam) sample preparation to accurately evaluate critical dimensions and profiles of ArF photo resist patterns without the use of a protective coating on the photo resist. In order to accomplish this, the FIB micro-sampling method that is one of effective FIB milling and fabrication method was employed. First a Si cap is picked up from a silicon wafer and fixed to ArF photo resist patterns to protect against ion beam irradiation. Then, a micro-sample, a piece of Si-capped ArF photo resist, was extracted from the bulk ArF photo resist. In this procedure, this silicon cap always protects ArF photo resist patterns against ion beam irradiation. For the next step, the micro-sample is fixed to a needle stub of the FIB-STEM (STEM: scanning transmission electron microscopy) compatible rotation holder. This sample on the needle stub was rotated 180 degrees and milled from the side of Si substrate. Lastly, the sample is milled to the thickness of 2μm. In this process, the ion beam is irradiating from the silicon substrate side to minimize the ion beam irradiation damages on the ArF photo resist patterns. EDX (EDX: Energy dispersive X-ray spectroscopy) analysis proved that no gallium ions were detected on the surface of the ArF photo resist patterns. The feasibility of high accelerating voltage observation of STEM to observe line edge roughness of a thick sample like 2μm without shrinkage has been demonstrated.
© (2006) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Hirohisa Okushima, Toshihiko Onozuka, Yasushi Kuroda, Toshie Yaguchi, Kaoru Umemura, Ryuichiro Tamochi, Kenji Watanabe, Norio Hasegawa, Isao Kawata, and Bart Rijpers "ArF photo resist pattern sample preparation method using FIB without protective coating", Proc. SPIE 6152, Metrology, Inspection, and Process Control for Microlithography XX, 615244 (24 March 2006); https://doi.org/10.1117/12.655984
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KEYWORDS
Silicon

Scanning transmission electron microscopy

Ion beams

Critical dimension metrology

Scanning electron microscopy

Coating

Gallium

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