TY - JOUR
T1 - On the trends and application of pattern density dependent isofocal dose of positive resists for 100 keV electron beam lithography
AU - Lopez, Gerald G.
AU - De Villafranca, Glen
AU - Azadi, Mohsen
AU - Metzler, Meredith G.
AU - Lister, Kevin
AU - Labella, Michael
AU - Eichfeld, Chad
AU - Belic, Nikola
AU - Hofmann, Ulrich
N1 - Funding Information:
This work was performed in part at the University of Pennsylvania Singh Center for Nanotechnology, a member of the National Nanotechnology Coordinated Infrastructure (NNCI), which is supported by the National Science Foundation (Grant No. ECCS-1542153). A special thanks goes to both the staff at the University of Delaware and the Pennsylvania State University for their time and efforts to further enable this research. The authors are also especially grateful for the generous advisement of Leonidas Ocola.
Publisher Copyright:
© 2018 Author(s).
PY - 2018/11/1
Y1 - 2018/11/1
N2 - This work examines the isofocality of four commercially available positive resists for electron beam lithography (EBL) at 100 keV: AR-P 6200 (commercially known as CSAR 62) by AllResist GmbH, ZEP520A by Zeon Corp., polymethylmethacrylate 950 A4 (950k molecular weight in anisole) by MicroChem Corp., and mr-PosEBR 0.3 by Micro Resist Technology GmbH. Isofocality is the operating point in a given process where a specific dose (namely, the isofocal dose) results in the same feature size (isofocal feature) independent of the effective blur ( blureff). The blureff is a lumped parameter that includes the effects of resist processing, spot size, beam focus, forward scattering, etc., which contributes to the final resist image. The isofocal feature is typically larger than the drawn target critical dimension (CD). The difference between the isofocal feature size and the CD target defines the isofocal bias. By analyzing the exposure latitudes across 0%, 25%, 50%, 75%, and 100% pattern densities ( ρ) with feature sizes ranging from 100 to 400 nm, the approximate pattern density dependent isofocal doses ( IFDρ) and isofocal biases ( IFΔρ) are identified for a silicon substrate across all four resists given their fixed processes at 100 keV. Examining the trends in isofocality in these positive resist processes, the proximity effect correction is adjusted to provide the empirically found IFDρ for 100 keV EBL on a silicon substrate.
AB - This work examines the isofocality of four commercially available positive resists for electron beam lithography (EBL) at 100 keV: AR-P 6200 (commercially known as CSAR 62) by AllResist GmbH, ZEP520A by Zeon Corp., polymethylmethacrylate 950 A4 (950k molecular weight in anisole) by MicroChem Corp., and mr-PosEBR 0.3 by Micro Resist Technology GmbH. Isofocality is the operating point in a given process where a specific dose (namely, the isofocal dose) results in the same feature size (isofocal feature) independent of the effective blur ( blureff). The blureff is a lumped parameter that includes the effects of resist processing, spot size, beam focus, forward scattering, etc., which contributes to the final resist image. The isofocal feature is typically larger than the drawn target critical dimension (CD). The difference between the isofocal feature size and the CD target defines the isofocal bias. By analyzing the exposure latitudes across 0%, 25%, 50%, 75%, and 100% pattern densities ( ρ) with feature sizes ranging from 100 to 400 nm, the approximate pattern density dependent isofocal doses ( IFDρ) and isofocal biases ( IFΔρ) are identified for a silicon substrate across all four resists given their fixed processes at 100 keV. Examining the trends in isofocality in these positive resist processes, the proximity effect correction is adjusted to provide the empirically found IFDρ for 100 keV EBL on a silicon substrate.
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U2 - 10.1116/1.5048206
DO - 10.1116/1.5048206
M3 - Article
AN - SCOPUS:85057196120
SN - 2166-2746
VL - 36
JO - Journal of Vacuum Science and Technology B
JF - Journal of Vacuum Science and Technology B
IS - 6
M1 - 06JA05
ER -