skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Demonstration of pattern transfer into sub-100 nm polysilicon line/space features patterned with extreme ultraviolet lithography

Abstract

In two separate experiments, we have successfully demonstrated the transfer of dense- and loose-pitch line/space (L/S) photoresist features, patterned with extreme ultraviolet (EUV) lithography, into an underlying hard mask material. In both experiments, a deep-UV photoresist ({approx}90 nm thick) was spin cast in bilayer format onto a hard mask (50-90 nm thick) and was subsequently exposed to EUV radiation using a 10x reduction EUV exposure system. The EUV reticle was fabricated at Motorola (Tempe, AZ) using a subtractive process with Ta-based absorbers on Mo/Si multilayer mask blanks. In the first set of experiments, following the EUV exposures, the L/S patterns were transferred first into a SiO{sub 2} hard mask (60 nm thick) using a reactive ion etch (RIE), and then into polysilicon (350 nm thick) using a triode-coupled plasma RIE etcher at the University of California, Berkeley, microfabrication facilities. The latter etch process, which produced steep (>85 degree sign ) sidewalls, employed a HBr/Cl chemistry with a large (>10:1) etch selectivity of polysilicon to silicon dioxide. In the second set of experiments, hard mask films of SiON (50 nm thick) and SiO{sub 2} (87 nm thick) were used. A RIE was performed at Motorola using a halogen gas chemistry thatmore » resulted in a hard mask-to-photoresist etch selectivity >3:1 and sidewall profile angles {>=}85 degree sign . Line edge roughness (LER) and linewidth critical dimension (CD) measurements were performed using Sandia's GORA(c) CD digital image analysis software. Low LER values (6-9 nm, 3{sigma}, one side) and good CD linearity (better than 10%) were demonstrated for the final pattern-transferred dense polysilicon L/S features from 80 to 175 nm. In addition, pattern transfer (into polysilicon) of loose-pitch (1:2) L/S features with CDs{>=}60 nm was demonstrated. (c) 1999 American Vacuum Society.« less

Authors:
 [1];  [1];  [1];  [2];  [2];  [2]
  1. Sandia National Laboratories, Livermore, California 94550 (United States)
  2. Motorola, Advanced Products Research and Development Laboratory, Austin, Texas 78721 (United States)
Publication Date:
OSTI Identifier:
20217898
Resource Type:
Journal Article
Journal Name:
Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena
Additional Journal Information:
Journal Volume: 17; Journal Issue: 6; Other Information: PBD: Nov 1999; Journal ID: ISSN 0734-211X
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; SILICON; OPTICAL SYSTEMS; EXTREME ULTRAVIOLET RADIATION; MASKING; LAYERS; ETCHING; INTEGRATED CIRCUITS; EXPERIMENTAL DATA; FABRICATION; SPUTTERING

Citation Formats

Cardinale, G F, Henderson, C C, Goldsmith, J E. M., Mangat, P J. S., Cobb, J, and Hector, S D. Demonstration of pattern transfer into sub-100 nm polysilicon line/space features patterned with extreme ultraviolet lithography. United States: N. p., 1999. Web. doi:10.1116/1.590936.
Cardinale, G F, Henderson, C C, Goldsmith, J E. M., Mangat, P J. S., Cobb, J, & Hector, S D. Demonstration of pattern transfer into sub-100 nm polysilicon line/space features patterned with extreme ultraviolet lithography. United States. https://doi.org/10.1116/1.590936
Cardinale, G F, Henderson, C C, Goldsmith, J E. M., Mangat, P J. S., Cobb, J, and Hector, S D. 1999. "Demonstration of pattern transfer into sub-100 nm polysilicon line/space features patterned with extreme ultraviolet lithography". United States. https://doi.org/10.1116/1.590936.
@article{osti_20217898,
title = {Demonstration of pattern transfer into sub-100 nm polysilicon line/space features patterned with extreme ultraviolet lithography},
author = {Cardinale, G F and Henderson, C C and Goldsmith, J E. M. and Mangat, P J. S. and Cobb, J and Hector, S D},
abstractNote = {In two separate experiments, we have successfully demonstrated the transfer of dense- and loose-pitch line/space (L/S) photoresist features, patterned with extreme ultraviolet (EUV) lithography, into an underlying hard mask material. In both experiments, a deep-UV photoresist ({approx}90 nm thick) was spin cast in bilayer format onto a hard mask (50-90 nm thick) and was subsequently exposed to EUV radiation using a 10x reduction EUV exposure system. The EUV reticle was fabricated at Motorola (Tempe, AZ) using a subtractive process with Ta-based absorbers on Mo/Si multilayer mask blanks. In the first set of experiments, following the EUV exposures, the L/S patterns were transferred first into a SiO{sub 2} hard mask (60 nm thick) using a reactive ion etch (RIE), and then into polysilicon (350 nm thick) using a triode-coupled plasma RIE etcher at the University of California, Berkeley, microfabrication facilities. The latter etch process, which produced steep (>85 degree sign ) sidewalls, employed a HBr/Cl chemistry with a large (>10:1) etch selectivity of polysilicon to silicon dioxide. In the second set of experiments, hard mask films of SiON (50 nm thick) and SiO{sub 2} (87 nm thick) were used. A RIE was performed at Motorola using a halogen gas chemistry that resulted in a hard mask-to-photoresist etch selectivity >3:1 and sidewall profile angles {>=}85 degree sign . Line edge roughness (LER) and linewidth critical dimension (CD) measurements were performed using Sandia's GORA(c) CD digital image analysis software. Low LER values (6-9 nm, 3{sigma}, one side) and good CD linearity (better than 10%) were demonstrated for the final pattern-transferred dense polysilicon L/S features from 80 to 175 nm. In addition, pattern transfer (into polysilicon) of loose-pitch (1:2) L/S features with CDs{>=}60 nm was demonstrated. (c) 1999 American Vacuum Society.},
doi = {10.1116/1.590936},
url = {https://www.osti.gov/biblio/20217898}, journal = {Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena},
issn = {0734-211X},
number = 6,
volume = 17,
place = {United States},
year = {Mon Nov 01 00:00:00 EST 1999},
month = {Mon Nov 01 00:00:00 EST 1999}
}