Low Temperature Flip Chip Bonding Using Squeegee-Embedded Au Nanoporous Bump Activated by VUV/O3 Treatment

Weixin Fu; Tatsushi Kaneda; Akiko Okada; Kaori Matsunaga; Shuichi Shoji; Mikiko Saito; Hiroshi Nishikawa; Jun Mizuno

doi:10.1007/s11664-018-6462-8

Low Temperature Flip Chip Bonding Using Squeegee-Embedded Au Nanoporous Bump Activated by VUV/O₃ Treatment

Weixin Fu, Tatsushi Kaneda, Akiko Okada, Kaori Matsunaga, Shuichi Shoji, Mikiko Saito, Hiroshi Nishikawa, Jun Mizuno^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

1 Citation (Scopus)

Abstract

This paper describes low-temperature bonding realized by squeegee-embedded Au nanoporous bumps that were activated by vacuum ultraviolet in the presence of oxygen (VUV/O₃). The VUV/O₃ technology is confirmed to be a suitable surface treatment technique for Au nanoporous bump bonding because it maintains the highly reactive surface of the Au nanoporous bumps during the treatment. X-ray photoelectron spectroscopy confirmed that the VUV/O₃ treatment was capable of removing organic contamination on the nanoporous surface, and scanning electron microscopy images showed that the ligament size of the nanoporous bumps stayed the same. After bonding, the ligament size of the VUV/O₃-treated nanoporous structure grew to 54 nm compared with 27 nm for the untreated samples. This increase in ligament size was attributed to the improvement in nanoporous coalescence by removing organic contamination that obstructed Au atom diffusion. Furthermore, the highest strength of the VUV/O₃-treated samples reached 8.9 MPa at a low temperature of 200°C, which was three times higher than that of the untreated sample. This technology is expected to assist manufacturing of future 3-D integrations.

Original language	English
Pages (from-to)	5952-5958
Number of pages	7
Journal	Journal of Electronic Materials
Volume	47
Issue number	10
DOIs	https://doi.org/10.1007/s11664-018-6462-8
Publication status	Published - 2018 Oct 1

Keywords

Au nanoporous
Flip chip bonding
VUV/O treatment
low-temperature bonding
squeegee embedding

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics
Electrical and Electronic Engineering
Materials Chemistry

Access to Document

10.1007/s11664-018-6462-8

Cite this

@article{ca5b0906a4fd42f38be1d59cdbb0c775,

title = "Low Temperature Flip Chip Bonding Using Squeegee-Embedded Au Nanoporous Bump Activated by VUV/O3 Treatment",

abstract = "This paper describes low-temperature bonding realized by squeegee-embedded Au nanoporous bumps that were activated by vacuum ultraviolet in the presence of oxygen (VUV/O3). The VUV/O3 technology is confirmed to be a suitable surface treatment technique for Au nanoporous bump bonding because it maintains the highly reactive surface of the Au nanoporous bumps during the treatment. X-ray photoelectron spectroscopy confirmed that the VUV/O3 treatment was capable of removing organic contamination on the nanoporous surface, and scanning electron microscopy images showed that the ligament size of the nanoporous bumps stayed the same. After bonding, the ligament size of the VUV/O3-treated nanoporous structure grew to 54 nm compared with 27 nm for the untreated samples. This increase in ligament size was attributed to the improvement in nanoporous coalescence by removing organic contamination that obstructed Au atom diffusion. Furthermore, the highest strength of the VUV/O3-treated samples reached 8.9 MPa at a low temperature of 200°C, which was three times higher than that of the untreated sample. This technology is expected to assist manufacturing of future 3-D integrations.",

keywords = "Au nanoporous, Flip chip bonding, VUV/O treatment, low-temperature bonding, squeegee embedding",

author = "Weixin Fu and Tatsushi Kaneda and Akiko Okada and Kaori Matsunaga and Shuichi Shoji and Mikiko Saito and Hiroshi Nishikawa and Jun Mizuno",

note = "Funding Information: This work is partly supported by Japan Ministry of Education, Culture, Sports Science and Technology (MEXT) Grant-in-Aid for Scientific Basic Research (A) No. 16H02349 and Scientific Basic Research (B) No. 25289841. The authors thank the MEXT Nanotechnology Platform Support Project of Waseda University. The author W. Fu also acknowledges the Leading Graduate Program in Science and Engineering, Waseda University from MEXT, Japan. Publisher Copyright: {\textcopyright} 2018, The Minerals, Metals & Materials Society.",

year = "2018",

month = oct,

day = "1",

doi = "10.1007/s11664-018-6462-8",

language = "English",

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T1 - Low Temperature Flip Chip Bonding Using Squeegee-Embedded Au Nanoporous Bump Activated by VUV/O3 Treatment

AU - Fu, Weixin

AU - Kaneda, Tatsushi

AU - Okada, Akiko

AU - Matsunaga, Kaori

AU - Shoji, Shuichi

AU - Saito, Mikiko

AU - Nishikawa, Hiroshi

AU - Mizuno, Jun

N1 - Funding Information: This work is partly supported by Japan Ministry of Education, Culture, Sports Science and Technology (MEXT) Grant-in-Aid for Scientific Basic Research (A) No. 16H02349 and Scientific Basic Research (B) No. 25289841. The authors thank the MEXT Nanotechnology Platform Support Project of Waseda University. The author W. Fu also acknowledges the Leading Graduate Program in Science and Engineering, Waseda University from MEXT, Japan. Publisher Copyright: © 2018, The Minerals, Metals & Materials Society.

PY - 2018/10/1

Y1 - 2018/10/1

N2 - This paper describes low-temperature bonding realized by squeegee-embedded Au nanoporous bumps that were activated by vacuum ultraviolet in the presence of oxygen (VUV/O3). The VUV/O3 technology is confirmed to be a suitable surface treatment technique for Au nanoporous bump bonding because it maintains the highly reactive surface of the Au nanoporous bumps during the treatment. X-ray photoelectron spectroscopy confirmed that the VUV/O3 treatment was capable of removing organic contamination on the nanoporous surface, and scanning electron microscopy images showed that the ligament size of the nanoporous bumps stayed the same. After bonding, the ligament size of the VUV/O3-treated nanoporous structure grew to 54 nm compared with 27 nm for the untreated samples. This increase in ligament size was attributed to the improvement in nanoporous coalescence by removing organic contamination that obstructed Au atom diffusion. Furthermore, the highest strength of the VUV/O3-treated samples reached 8.9 MPa at a low temperature of 200°C, which was three times higher than that of the untreated sample. This technology is expected to assist manufacturing of future 3-D integrations.

AB - This paper describes low-temperature bonding realized by squeegee-embedded Au nanoporous bumps that were activated by vacuum ultraviolet in the presence of oxygen (VUV/O3). The VUV/O3 technology is confirmed to be a suitable surface treatment technique for Au nanoporous bump bonding because it maintains the highly reactive surface of the Au nanoporous bumps during the treatment. X-ray photoelectron spectroscopy confirmed that the VUV/O3 treatment was capable of removing organic contamination on the nanoporous surface, and scanning electron microscopy images showed that the ligament size of the nanoporous bumps stayed the same. After bonding, the ligament size of the VUV/O3-treated nanoporous structure grew to 54 nm compared with 27 nm for the untreated samples. This increase in ligament size was attributed to the improvement in nanoporous coalescence by removing organic contamination that obstructed Au atom diffusion. Furthermore, the highest strength of the VUV/O3-treated samples reached 8.9 MPa at a low temperature of 200°C, which was three times higher than that of the untreated sample. This technology is expected to assist manufacturing of future 3-D integrations.

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