Paper
26 June 2003 Development of organic bottom antireflective coating for 157-nm lithography
Shigeo Irie, Masato Shigematsu, Seiro Miyoshi, Rikimaru Sakamoto, Kenichi Mizusawa, Yasuyuki Nakajima, Toshiro Itani
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Abstract
In 157-nm lithography, an organic bottom-antireflective-coating (BARC), which has been mainly used as an antireflective technology in KrF or ArF lithography, is needed to reduce reflection from the substrate under the resist. To apply a conventional BARC to 157-nm lithography, the BARC thickness must be thinner than the BARC thickness used in KrF or ArF lithography. Because conventional BARCs have a lower dry-etching rate than resists with a fluorinated polymer for 157-nm lithography and the thickness of remaining resist after BARC dry-etching may be greatly reduced. Moreover, the substrate reflection under a conventional thin BARC cannot be completely controlled since the k-value of the extinction coefficient at a 157-nm wavelength is small. Therefore, a BARC material for 157-nm lithography must have a higher k-value at the 157-nm, a higher dry-etching rate than resists with a fluorinated polymer, good matching between the fluorinated resist and the BARC material to ensure a good resist pattern shape, and low outgassing from the BARC material. In this paper, we evaluate a newly developed BARC material (NCA646) for 157-nm lithography. We found that the k-value of this BARC material was 0.45 (1.8 times that of a conventional BARC (DUV30J; Brewer Science, Inc)), and the ratio of the dry-etching rate to that of a KrF resist was 1.53 (1.6 times that of DUV30J). These improvements were achieved by introducing a new chromophore into a BARC polymer of novolak resin. Furthermore, the amount of outgassing from the BARC material when irradiated by 157-nm light was close to 0 ng (irradiated condition; 100 mJ/cm2), and resist patterns with no footing were obtained with four kinds of fluorinated resist on this BARC material. We concluded that this BARC material was suitable for 157-nm lithography.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Shigeo Irie, Masato Shigematsu, Seiro Miyoshi, Rikimaru Sakamoto, Kenichi Mizusawa, Yasuyuki Nakajima, and Toshiro Itani "Development of organic bottom antireflective coating for 157-nm lithography", Proc. SPIE 5040, Optical Microlithography XVI, (26 June 2003); https://doi.org/10.1117/12.485369
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KEYWORDS
Polymers

Lithography

Etching

Refractive index

Chromophores

Polymer thin films

Reflection

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