TY - GEN
T1 - Study of Low-residual Stress Amorphous Film Deposition Method for LiTaO3/Quartz or LiNbO3/Quartz Bonding toward 5G Surface Acoustic Wave Devices
AU - Tezuka, Ami
AU - Kuwae, Hiroyuki
AU - Yamada, Kosuke
AU - Shoji, Shuichi
AU - Kakio, Shoji
AU - Mizuno, Jun
N1 - Funding Information:
ACKNOWLEDGEMENT We gratefully acknowledge JAPAN STEEL WORKS, Ltd. This work is partly supported by Japan Ministry of Education, Culture, Sport Science & Technology (MEXT) Grant-in-Aid for Scientific Basic Research (A) No. 16H02349 and Young Scientists No. 18K13770. The authors thank for MEXT Nanotechnology Platform Support Project of Waseda University.
Publisher Copyright:
© 2019 Japan Institute of Electronics Packaging.
PY - 2019/4
Y1 - 2019/4
N2 - LiTaO3 (LT) or LiNbO3 (LN)/Quartz bonded substrates with an amorphous intermediate layer were proposed to achieve both a large surface acoustic wave (SAW) velocity and a smaller temperature coefficient of frequency. Residual stress reduction of the amorphous film is expected to improve the bonding strength of a SAW substrate. In this report, we studied a method of low-residual stress amorphous film deposition for LT or LN/Quartz bonding. The residual stress of the LT substrate with an amorphous SiO2 or Al2O3 film deposited by ion beam sputtering, electron cyclotron resonance sputtering, and atomic layer deposition was evaluated. The LT substrate with the amorphous Al2O3 film deposited by ALD had the minimum warpage (-0.152 μm) and residual stress (127.3 MPa). The residual stress of the Al2O3 film deposited by ALD might be reduced because almost the same thickness of the Al2O3 film was deposited on both sides of the LT substrate at the same time. The maximum bonding strength of 3.7 MPa was achieved in the substrate with the Al2O3 film deposited by ALD. From these results, LT or LN/Quartz substrates with the Al2O3 film deposited by ALD are promising materials to reduce residual stress toward SAW devices for 5G mobile communication.
AB - LiTaO3 (LT) or LiNbO3 (LN)/Quartz bonded substrates with an amorphous intermediate layer were proposed to achieve both a large surface acoustic wave (SAW) velocity and a smaller temperature coefficient of frequency. Residual stress reduction of the amorphous film is expected to improve the bonding strength of a SAW substrate. In this report, we studied a method of low-residual stress amorphous film deposition for LT or LN/Quartz bonding. The residual stress of the LT substrate with an amorphous SiO2 or Al2O3 film deposited by ion beam sputtering, electron cyclotron resonance sputtering, and atomic layer deposition was evaluated. The LT substrate with the amorphous Al2O3 film deposited by ALD had the minimum warpage (-0.152 μm) and residual stress (127.3 MPa). The residual stress of the Al2O3 film deposited by ALD might be reduced because almost the same thickness of the Al2O3 film was deposited on both sides of the LT substrate at the same time. The maximum bonding strength of 3.7 MPa was achieved in the substrate with the Al2O3 film deposited by ALD. From these results, LT or LN/Quartz substrates with the Al2O3 film deposited by ALD are promising materials to reduce residual stress toward SAW devices for 5G mobile communication.
KW - Amorphous film
KW - Amorphous intermediate bonding
KW - LiNbO3
KW - LiTaO3
KW - Quartz
KW - Residual stress
KW - SAW device
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U2 - 10.23919/ICEP.2019.8733501
DO - 10.23919/ICEP.2019.8733501
M3 - Conference contribution
AN - SCOPUS:85068309815
T3 - 2019 International Conference on Electronics Packaging, ICEP 2019
SP - 414
EP - 417
BT - 2019 International Conference on Electronics Packaging, ICEP 2019
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2019 International Conference on Electronics Packaging, ICEP 2019
Y2 - 17 April 2019 through 20 April 2019
ER -