Growth competition between layer-type and porous-type Cu3Sn in microbumps

David T. Chu; Yi-Cheng Chu; Jie-An Lin; Yi-Ting Chen; Chun-Chieh Wang; Yen-Fang Song; Cheng-Cheng Chiang; Chih Chen; K.N. Tu

doi:10.1016/j.microrel.2017.10.001

Growth competition between layer-type and porous-type Cu₃Sn in microbumps

David T. Chu, Yi-Cheng Chu, Jie-An Lin, Yi-Ting Chen, Chun-Chieh Wang, Yen-Fang Song, Cheng-Cheng Chiang, Chih Chen, K.N. Tu^*

^*Corresponding author for this work

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

26 Citations (Scopus)

Abstract

Experimental study of growth competition between the co-existing layer-type and porous-type Cu₃Sn in solder microbumps of Cu/SnAg/Cu is reported. The thickness of the SnAg solder is about 14 μm and the Cu column on both sides is 20 μm. Upon wetting-reflow, the solder is reacted completely to form Cu–Sn intermetallic compounds in a multi-layered structure of Cu/Cu₃Sn/Cu₆Sn₅/Cu₃Sn/Cu. Upon further annealing at 220 °C and 260 °C, we obtain Cu/Cu₃Sn/porous Cu₃Sn/Cu₃Sn/Cu, in which both types of Cu₃Sn co-exist and form an interface. In the layer-type growth, we assume Cu to be the dominant diffusing species, coming from the Cu column. The Cu reacts with Cu₆Sn₅ to grow the Cu₃Sn layer. In the porous-type growth, we assume Sn to be the dominant diffusing species, coming from the depletion of Sn in Cu₆Sn₅. The depleted Cu₆Sn₅ transforms to the porous-type Cu₃Sn. At the same time, the Sn diffuses to the side-wall of Cu column to form a coating of Cu₃Sn. Experimental observations of 3-dimensional distribution of voids in the porous-type Cu₃Sn are performed by synchrotron radiation tomography; the voids are interconnected for the out-diffusion of Sn. The competing growth between the layer-type and the porous-type Cu₃Sn is analyzed.

Original language	English
Pages (from-to)	32-37
Journal	Microelectronics Reliability
Volume	79
DOIs	https://doi.org/10.1016/j.microrel.2017.10.001
Publication status	Published - 1 Dec 2017
Externally published	Yes

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Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].

Research Keywords

Growth competition
Intermetallic compounds
Microbumps
Porous structure

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title = "Growth competition between layer-type and porous-type Cu3Sn in microbumps",

abstract = "Experimental study of growth competition between the co-existing layer-type and porous-type Cu3Sn in solder microbumps of Cu/SnAg/Cu is reported. The thickness of the SnAg solder is about 14 μm and the Cu column on both sides is 20 μm. Upon wetting-reflow, the solder is reacted completely to form Cu–Sn intermetallic compounds in a multi-layered structure of Cu/Cu3Sn/Cu6Sn5/Cu3Sn/Cu. Upon further annealing at 220 °C and 260 °C, we obtain Cu/Cu3Sn/porous Cu3Sn/Cu3Sn/Cu, in which both types of Cu3Sn co-exist and form an interface. In the layer-type growth, we assume Cu to be the dominant diffusing species, coming from the Cu column. The Cu reacts with Cu6Sn5 to grow the Cu3Sn layer. In the porous-type growth, we assume Sn to be the dominant diffusing species, coming from the depletion of Sn in Cu6Sn5. The depleted Cu6Sn5 transforms to the porous-type Cu3Sn. At the same time, the Sn diffuses to the side-wall of Cu column to form a coating of Cu3Sn. Experimental observations of 3-dimensional distribution of voids in the porous-type Cu3Sn are performed by synchrotron radiation tomography; the voids are interconnected for the out-diffusion of Sn. The competing growth between the layer-type and the porous-type Cu3Sn is analyzed.",

keywords = "Growth competition, Intermetallic compounds, Microbumps, Porous structure",

author = "Chu, {David T.} and Yi-Cheng Chu and Jie-An Lin and Yi-Ting Chen and Chun-Chieh Wang and Yen-Fang Song and Cheng-Cheng Chiang and Chih Chen and K.N. Tu",

note = "Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].",

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doi = "10.1016/j.microrel.2017.10.001",

language = "English",

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TY - JOUR

T1 - Growth competition between layer-type and porous-type Cu3Sn in microbumps

AU - Chu, David T.

AU - Chu, Yi-Cheng

AU - Lin, Jie-An

AU - Chen, Yi-Ting

AU - Wang, Chun-Chieh

AU - Song, Yen-Fang

AU - Chiang, Cheng-Cheng

AU - Chen, Chih

AU - Tu, K.N.

N1 - Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].

PY - 2017/12/1

Y1 - 2017/12/1

N2 - Experimental study of growth competition between the co-existing layer-type and porous-type Cu3Sn in solder microbumps of Cu/SnAg/Cu is reported. The thickness of the SnAg solder is about 14 μm and the Cu column on both sides is 20 μm. Upon wetting-reflow, the solder is reacted completely to form Cu–Sn intermetallic compounds in a multi-layered structure of Cu/Cu3Sn/Cu6Sn5/Cu3Sn/Cu. Upon further annealing at 220 °C and 260 °C, we obtain Cu/Cu3Sn/porous Cu3Sn/Cu3Sn/Cu, in which both types of Cu3Sn co-exist and form an interface. In the layer-type growth, we assume Cu to be the dominant diffusing species, coming from the Cu column. The Cu reacts with Cu6Sn5 to grow the Cu3Sn layer. In the porous-type growth, we assume Sn to be the dominant diffusing species, coming from the depletion of Sn in Cu6Sn5. The depleted Cu6Sn5 transforms to the porous-type Cu3Sn. At the same time, the Sn diffuses to the side-wall of Cu column to form a coating of Cu3Sn. Experimental observations of 3-dimensional distribution of voids in the porous-type Cu3Sn are performed by synchrotron radiation tomography; the voids are interconnected for the out-diffusion of Sn. The competing growth between the layer-type and the porous-type Cu3Sn is analyzed.

AB - Experimental study of growth competition between the co-existing layer-type and porous-type Cu3Sn in solder microbumps of Cu/SnAg/Cu is reported. The thickness of the SnAg solder is about 14 μm and the Cu column on both sides is 20 μm. Upon wetting-reflow, the solder is reacted completely to form Cu–Sn intermetallic compounds in a multi-layered structure of Cu/Cu3Sn/Cu6Sn5/Cu3Sn/Cu. Upon further annealing at 220 °C and 260 °C, we obtain Cu/Cu3Sn/porous Cu3Sn/Cu3Sn/Cu, in which both types of Cu3Sn co-exist and form an interface. In the layer-type growth, we assume Cu to be the dominant diffusing species, coming from the Cu column. The Cu reacts with Cu6Sn5 to grow the Cu3Sn layer. In the porous-type growth, we assume Sn to be the dominant diffusing species, coming from the depletion of Sn in Cu6Sn5. The depleted Cu6Sn5 transforms to the porous-type Cu3Sn. At the same time, the Sn diffuses to the side-wall of Cu column to form a coating of Cu3Sn. Experimental observations of 3-dimensional distribution of voids in the porous-type Cu3Sn are performed by synchrotron radiation tomography; the voids are interconnected for the out-diffusion of Sn. The competing growth between the layer-type and the porous-type Cu3Sn is analyzed.

KW - Growth competition

KW - Intermetallic compounds

KW - Microbumps

KW - Porous structure

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U2 - 10.1016/j.microrel.2017.10.001

DO - 10.1016/j.microrel.2017.10.001

M3 - RGC 21 - Publication in refereed journal

SN - 0026-2714

VL - 79

SP - 32

EP - 37

JO - Microelectronics Reliability

JF - Microelectronics Reliability

ER -