TY - GEN
T1 - ST-quartz/LiTaO3 direct bonding using SiO2 amorphous layers with VUV/O3 pre-treatment for a novel 5G surface acoustic wave device
AU - Suzaki, Haruka
AU - Kuwae, Hiroyuki
AU - Okada, Akiko
AU - Ma, Bo
AU - Shoji, Shuichi
AU - Mizuno, Jun
N1 - Funding Information:
We gratefully acknowledge Japan STEEL WORKS, Ltd. and FINE CRYSTAL Co., Ltd, for their provision of materials, discussion and assistance. This work was supported in part by the Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT) and a Grant-in-Aid for Scientific Basic Research (S) (No. 23226010) and Scientific Basic Research (B) (No. 2528924)
Publisher Copyright:
© 2016 The Japan Institute of Electronics Packaging.
PY - 2016/6/7
Y1 - 2016/6/7
N2 - This paper describes a novel ST-cut quartz (ST-quartz)/LiTaO3 (LT) direct bonding for surface acoustic wave (SAW) devices of next 5G mobile communication. The ST-quartz and LT were bonded to fabricate temperature compensated piezoelectric substrates using amorphous SiO2 (α-SiO2) intermediate layers. The α-SiO2 thin layer was prepared on each substrate by ion beam sputtering (IBS) to realize highly active bonding interfaces and treated by vacuum ultraviolet irradiation in the presence of oxygen gas (VUV/O3). Then they were bonded under pressure of 5 MPa at 200 °C for 15 min in 100 kPa vacuum atmosphere. The tensile strength of 2.9 MPa was achieved in α-SiO2 substrate which is six times stronger than other samples; without intermediate layers or VUV/O3 pre-treatment. In addition, VUV/O3 bonding was compared with Mega-sonic bonding. VUV/O3 treated sample with AIB method slightly increase the bonding strength and achieved the same level of Mega-sonic bonding sample with AIB. Hence, it is indicated that AIB method could prepare the considerably activated surface even using low vacuum condition and affect effectively to hetero-monocrystalline bonding. This result suggested the proposed ST-quartz/LT direct bonding is a promising technique for future 5G SAW devices.
AB - This paper describes a novel ST-cut quartz (ST-quartz)/LiTaO3 (LT) direct bonding for surface acoustic wave (SAW) devices of next 5G mobile communication. The ST-quartz and LT were bonded to fabricate temperature compensated piezoelectric substrates using amorphous SiO2 (α-SiO2) intermediate layers. The α-SiO2 thin layer was prepared on each substrate by ion beam sputtering (IBS) to realize highly active bonding interfaces and treated by vacuum ultraviolet irradiation in the presence of oxygen gas (VUV/O3). Then they were bonded under pressure of 5 MPa at 200 °C for 15 min in 100 kPa vacuum atmosphere. The tensile strength of 2.9 MPa was achieved in α-SiO2 substrate which is six times stronger than other samples; without intermediate layers or VUV/O3 pre-treatment. In addition, VUV/O3 bonding was compared with Mega-sonic bonding. VUV/O3 treated sample with AIB method slightly increase the bonding strength and achieved the same level of Mega-sonic bonding sample with AIB. Hence, it is indicated that AIB method could prepare the considerably activated surface even using low vacuum condition and affect effectively to hetero-monocrystalline bonding. This result suggested the proposed ST-quartz/LT direct bonding is a promising technique for future 5G SAW devices.
KW - Amorphous SiO2
KW - Low temperature bonding
KW - Mega-sonic cleaningt
KW - VUV/O3 treatment
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U2 - 10.1109/ICEP.2016.7486865
DO - 10.1109/ICEP.2016.7486865
M3 - Conference contribution
AN - SCOPUS:84978193818
T3 - 2016 International Conference on Electronics Packaging, ICEP 2016
SP - 443
EP - 446
BT - 2016 International Conference on Electronics Packaging, ICEP 2016
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2016 International Conference on Electronics Packaging, ICEP 2016
Y2 - 20 April 2016 through 22 April 2016
ER -