A fluxless Au-Sn bonding process of tin-rich compositions achieved in ambient air

Ricky W. Chuang, Dongwook Kim, Jeong Park, Chin C. Lee

Research output: Contribution to journalConference article

5 Citations (Scopus)

Abstract

A new alternative fluxless bonding process conducted in ambient air is reported based on two different Au-Sn multilayer composite designs that are substantially tin-rich; namely, one with compositions of 80 at.% Sn (70.54 wt. % Sn) and 20 at. % Au (29.46 wt. % Au), and another with 95 at. % Sn (91.82 wt. % Sn) and 5 at. % Au (8.18 wt. % Au). We believe that this is the first time that Au-Sn bonding is achieved in air without the use of flux. The bonding process temperatures chosen for constructing 80Sn-20Au and 95Sn-5Au joints are 285°C and 225°C, respectively. Once produced, both types of joints were examined using the scanning acoustic microscopy (SAM) to confirm the bonding quality and the results obtained are nearly void-free. To study the microstructure and composition of the samples the scanning electron microscopy (SEM) equipped with energy dispersive x-ray (EDX) detector were conducted across the 95Sn-5Au joint cross-section and a thickness of 3.78 μm was uniformly identified throughout the joint. Furthermore, the EDX data obtained have consistently shown that many AuSn2 grains were identified and found to be embedded in a matrix with a mixture of AuSn2 and AuSn4, as obtained from 95Sn-5Au specimens. In addition, the shear tests conducted on the samples unequivocally suggest the shear strength of each joint measured is actually greater than the die itself. Finally, the remelting temperatures of 80Sn-20Au and 95Sn-5Au solder specimens ranging from 275 to 281°C and 214 to 220°C, respectively, were also experimentally determined.

Original languageEnglish
Pages (from-to)134-137
Number of pages4
JournalProceedings - Electronic Components and Technology Conference
Publication statusPublished - 2002 Jan 1
Event52nd Electronic Components and Technology Conference - San Diego, CA, United States
Duration: 2002 May 282002 May 31

Fingerprint

Tin
Air
Chemical analysis
X rays
Remelting
Shear strength
Soldering alloys
Multilayers
Fluxes
Detectors
Temperature
Microstructure
Scanning electron microscopy
Composite materials

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

Cite this

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title = "A fluxless Au-Sn bonding process of tin-rich compositions achieved in ambient air",
abstract = "A new alternative fluxless bonding process conducted in ambient air is reported based on two different Au-Sn multilayer composite designs that are substantially tin-rich; namely, one with compositions of 80 at.{\%} Sn (70.54 wt. {\%} Sn) and 20 at. {\%} Au (29.46 wt. {\%} Au), and another with 95 at. {\%} Sn (91.82 wt. {\%} Sn) and 5 at. {\%} Au (8.18 wt. {\%} Au). We believe that this is the first time that Au-Sn bonding is achieved in air without the use of flux. The bonding process temperatures chosen for constructing 80Sn-20Au and 95Sn-5Au joints are 285°C and 225°C, respectively. Once produced, both types of joints were examined using the scanning acoustic microscopy (SAM) to confirm the bonding quality and the results obtained are nearly void-free. To study the microstructure and composition of the samples the scanning electron microscopy (SEM) equipped with energy dispersive x-ray (EDX) detector were conducted across the 95Sn-5Au joint cross-section and a thickness of 3.78 μm was uniformly identified throughout the joint. Furthermore, the EDX data obtained have consistently shown that many AuSn2 grains were identified and found to be embedded in a matrix with a mixture of AuSn2 and AuSn4, as obtained from 95Sn-5Au specimens. In addition, the shear tests conducted on the samples unequivocally suggest the shear strength of each joint measured is actually greater than the die itself. Finally, the remelting temperatures of 80Sn-20Au and 95Sn-5Au solder specimens ranging from 275 to 281°C and 214 to 220°C, respectively, were also experimentally determined.",
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A fluxless Au-Sn bonding process of tin-rich compositions achieved in ambient air. / Chuang, Ricky W.; Kim, Dongwook; Park, Jeong; Lee, Chin C.

In: Proceedings - Electronic Components and Technology Conference, 01.01.2002, p. 134-137.

Research output: Contribution to journalConference article

TY - JOUR

T1 - A fluxless Au-Sn bonding process of tin-rich compositions achieved in ambient air

AU - Chuang, Ricky W.

AU - Kim, Dongwook

AU - Park, Jeong

AU - Lee, Chin C.

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N2 - A new alternative fluxless bonding process conducted in ambient air is reported based on two different Au-Sn multilayer composite designs that are substantially tin-rich; namely, one with compositions of 80 at.% Sn (70.54 wt. % Sn) and 20 at. % Au (29.46 wt. % Au), and another with 95 at. % Sn (91.82 wt. % Sn) and 5 at. % Au (8.18 wt. % Au). We believe that this is the first time that Au-Sn bonding is achieved in air without the use of flux. The bonding process temperatures chosen for constructing 80Sn-20Au and 95Sn-5Au joints are 285°C and 225°C, respectively. Once produced, both types of joints were examined using the scanning acoustic microscopy (SAM) to confirm the bonding quality and the results obtained are nearly void-free. To study the microstructure and composition of the samples the scanning electron microscopy (SEM) equipped with energy dispersive x-ray (EDX) detector were conducted across the 95Sn-5Au joint cross-section and a thickness of 3.78 μm was uniformly identified throughout the joint. Furthermore, the EDX data obtained have consistently shown that many AuSn2 grains were identified and found to be embedded in a matrix with a mixture of AuSn2 and AuSn4, as obtained from 95Sn-5Au specimens. In addition, the shear tests conducted on the samples unequivocally suggest the shear strength of each joint measured is actually greater than the die itself. Finally, the remelting temperatures of 80Sn-20Au and 95Sn-5Au solder specimens ranging from 275 to 281°C and 214 to 220°C, respectively, were also experimentally determined.

AB - A new alternative fluxless bonding process conducted in ambient air is reported based on two different Au-Sn multilayer composite designs that are substantially tin-rich; namely, one with compositions of 80 at.% Sn (70.54 wt. % Sn) and 20 at. % Au (29.46 wt. % Au), and another with 95 at. % Sn (91.82 wt. % Sn) and 5 at. % Au (8.18 wt. % Au). We believe that this is the first time that Au-Sn bonding is achieved in air without the use of flux. The bonding process temperatures chosen for constructing 80Sn-20Au and 95Sn-5Au joints are 285°C and 225°C, respectively. Once produced, both types of joints were examined using the scanning acoustic microscopy (SAM) to confirm the bonding quality and the results obtained are nearly void-free. To study the microstructure and composition of the samples the scanning electron microscopy (SEM) equipped with energy dispersive x-ray (EDX) detector were conducted across the 95Sn-5Au joint cross-section and a thickness of 3.78 μm was uniformly identified throughout the joint. Furthermore, the EDX data obtained have consistently shown that many AuSn2 grains were identified and found to be embedded in a matrix with a mixture of AuSn2 and AuSn4, as obtained from 95Sn-5Au specimens. In addition, the shear tests conducted on the samples unequivocally suggest the shear strength of each joint measured is actually greater than the die itself. Finally, the remelting temperatures of 80Sn-20Au and 95Sn-5Au solder specimens ranging from 275 to 281°C and 214 to 220°C, respectively, were also experimentally determined.

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