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Title: ScAlN etch mask for highly selective silicon etching

Abstract

Here, this work reports the utilization of a recently developed film, ScAlN, as a silicon etch mask offering significant improvements in high etch selectivity to silicon. Utilization of ScAlN as a fluorine chemistry based deep reactive ion etch mask demonstrated etch selectivity at 23 550:1, four times better than AlN, 11 times better than Al2O3, and 148 times better than silicon dioxide with significantly less resputtering at high bias voltage than either Al2O3 or AlN. Ellipsometry film thickness measurements show less than 0.3 nm/min mask erosion rates for ScAlN. Micromasking of resputtered Al for Al2O3, AlN, and ScAlN etch masks is also reported here, utilizing cross-sectional scanning electron microscope and confocal microscope roughness measurements. With lower etch bias, the reduced etch rate can be optimized to achieve a trench bottom surface roughness that is comparable to SiO2 etch masks. Etch mask selectivity enabled by ScAlN is likely to make significant improvements in microelectromechanical systems, wafer level packaging, and plasma dicing of silicon.

Authors:
 [1];  [1];  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1406366
Alternate Identifier(s):
OSTI ID: 1380046
Report Number(s):
SAND-2017-11101J
Journal ID: ISSN 2166-2746; 657803
Grant/Contract Number:  
AC04-94AL85000; 180906
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Vacuum Science and Technology B
Additional Journal Information:
Journal Volume: 35; Journal Issue: 5; Journal ID: ISSN 2166-2746
Publisher:
American Vacuum Society/AIP
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Henry, Michael David, Young, Travis R., and Griffin, Ben. ScAlN etch mask for highly selective silicon etching. United States: N. p., 2017. Web. doi:10.1116/1.4994841.
Henry, Michael David, Young, Travis R., & Griffin, Ben. ScAlN etch mask for highly selective silicon etching. United States. doi:https://doi.org/10.1116/1.4994841
Henry, Michael David, Young, Travis R., and Griffin, Ben. Fri . "ScAlN etch mask for highly selective silicon etching". United States. doi:https://doi.org/10.1116/1.4994841. https://www.osti.gov/servlets/purl/1406366.
@article{osti_1406366,
title = {ScAlN etch mask for highly selective silicon etching},
author = {Henry, Michael David and Young, Travis R. and Griffin, Ben},
abstractNote = {Here, this work reports the utilization of a recently developed film, ScAlN, as a silicon etch mask offering significant improvements in high etch selectivity to silicon. Utilization of ScAlN as a fluorine chemistry based deep reactive ion etch mask demonstrated etch selectivity at 23 550:1, four times better than AlN, 11 times better than Al2O3, and 148 times better than silicon dioxide with significantly less resputtering at high bias voltage than either Al2O3 or AlN. Ellipsometry film thickness measurements show less than 0.3 nm/min mask erosion rates for ScAlN. Micromasking of resputtered Al for Al2O3, AlN, and ScAlN etch masks is also reported here, utilizing cross-sectional scanning electron microscope and confocal microscope roughness measurements. With lower etch bias, the reduced etch rate can be optimized to achieve a trench bottom surface roughness that is comparable to SiO2 etch masks. Etch mask selectivity enabled by ScAlN is likely to make significant improvements in microelectromechanical systems, wafer level packaging, and plasma dicing of silicon.},
doi = {10.1116/1.4994841},
journal = {Journal of Vacuum Science and Technology B},
number = 5,
volume = 35,
place = {United States},
year = {2017},
month = {9}
}

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