TY - GEN
T1 - Observation of Thermal Expansion Behavior of Nanotwinned-Cu/SiO2 & Regular-Cu/SiO2 Hybrid Structure via In-Situ Heating AFM
AU - Lin, Huai En
AU - Chiu, Wei Lan
AU - Chang, Hsiang Hung
AU - Chen, Chih
N1 - Publisher Copyright:
© 2024 IEEE.
PY - 2024
Y1 - 2024
N2 - One critical challenge in downscaling hybrid bonding is the decrease in the expansion of Cu pads in dielectric vias with decreasing dimensions. A deeper understanding on the mechanism of hybrid bonding is required. In this study, we investigated the thermal expansion characteristics of both nanotwinned-Cu (NT-Cu) and regular-Cu in SiO2 hybrid structure using in-situ heating atomic force microscopy (AFM). The scanning microscopy was conducted from room temperature to 100, 150 and 200 under an argon atmosphere. It was found that the NT-Cu/SiO2 via with 8 μm in diameter exhibited a 6-nm recess at room temperature, began to protrude at 150 , and eventually transitioned to a 4-nm protrusion at 200 . This result provides direct evidence of the hybrid bonding mechanism. The NT-Cu/SiO2 samples could also be bonded at 150 for 2 h. The regular-Cu via exhibited a similar thermal expansion during the measurement. In contrast, the expansion of the regular-Cu via was discovered to be larger than that of the NT-Cu via, which could be attributed to the difference in Young's modulus. The plastic deformation was also observed to contribute to the total expansion in Cu/SiO2 vias over 150 . This work provides deeper insight into the mechanism of hybrid bonding and design of Cu-Cu joints.
AB - One critical challenge in downscaling hybrid bonding is the decrease in the expansion of Cu pads in dielectric vias with decreasing dimensions. A deeper understanding on the mechanism of hybrid bonding is required. In this study, we investigated the thermal expansion characteristics of both nanotwinned-Cu (NT-Cu) and regular-Cu in SiO2 hybrid structure using in-situ heating atomic force microscopy (AFM). The scanning microscopy was conducted from room temperature to 100, 150 and 200 under an argon atmosphere. It was found that the NT-Cu/SiO2 via with 8 μm in diameter exhibited a 6-nm recess at room temperature, began to protrude at 150 , and eventually transitioned to a 4-nm protrusion at 200 . This result provides direct evidence of the hybrid bonding mechanism. The NT-Cu/SiO2 samples could also be bonded at 150 for 2 h. The regular-Cu via exhibited a similar thermal expansion during the measurement. In contrast, the expansion of the regular-Cu via was discovered to be larger than that of the NT-Cu via, which could be attributed to the difference in Young's modulus. The plastic deformation was also observed to contribute to the total expansion in Cu/SiO2 vias over 150 . This work provides deeper insight into the mechanism of hybrid bonding and design of Cu-Cu joints.
KW - 3D IC
KW - Coefficient of thermal expansion
KW - Cu/SiO hybrid bonding
KW - In-situ heating AFM
KW - Nanotwinned Cu
UR - http://www.scopus.com/inward/record.url?scp=85197693338&partnerID=8YFLogxK
U2 - 10.1109/ECTC51529.2024.00131
DO - 10.1109/ECTC51529.2024.00131
M3 - Conference contribution
AN - SCOPUS:85197693338
T3 - Proceedings - Electronic Components and Technology Conference
SP - 816
EP - 820
BT - Proceedings - IEEE 74th Electronic Components and Technology Conference, ECTC 2024
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 74th IEEE Electronic Components and Technology Conference, ECTC 2024
Y2 - 28 May 2024 through 31 May 2024
ER -