TY - JOUR
T1 - Effect of Ag content on the microstructure of Sn-Ag-Cu based solder alloys
AU - Reid, M.
AU - Punch, J.
AU - Collins, M.
AU - Ryan, C.
PY - 2008/9/19
Y1 - 2008/9/19
N2 - Purpose The purpose of this paper is to examine the microstructure and evaluate the intermetallic compounds in the following lead-free solder alloys: Sn98.5Ag1.0Cu0.5 (SAC105) Sn97.5Ag2.0Cu0.5 (SAC205) Sn96.5Ag3.0Cu0.5 (SAC305) and Sn95.5Ag4.0Cu0.5 (SAC405). Design/methodology/approach X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to identify the main intermetallics formed during solidification. Differential scanning calorimetry (DSC) was used to investigate the undercooling properties of each of the alloys. Findings By using XRD analysis in addition to energy dispersive spectroscopy (EDS) it was found that the main intermetallics were Cu6Sn5 and Ag3Sn in a Sn matrix. Plate-like ε-Ag3Sn intermetallics were observed for all four alloys. Solder alloys SAC105, SAC205 and SAC305 showed a similar microstructure, while SAC405 displayed a fine microstructure with intermetallic phases dense within the Sn matrix. Originality/value Currently, low-silver content SAC alloys are being investigated due to their lower cost, however, the overall reliability of an alloy can be greatly affected by the microstructure and this should be taken into consideration when choosing an alloy. The size and number of Ag3Sn plate-like intermetallics can affect the reliability as they act as a site for crack propagation.
AB - Purpose The purpose of this paper is to examine the microstructure and evaluate the intermetallic compounds in the following lead-free solder alloys: Sn98.5Ag1.0Cu0.5 (SAC105) Sn97.5Ag2.0Cu0.5 (SAC205) Sn96.5Ag3.0Cu0.5 (SAC305) and Sn95.5Ag4.0Cu0.5 (SAC405). Design/methodology/approach X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to identify the main intermetallics formed during solidification. Differential scanning calorimetry (DSC) was used to investigate the undercooling properties of each of the alloys. Findings By using XRD analysis in addition to energy dispersive spectroscopy (EDS) it was found that the main intermetallics were Cu6Sn5 and Ag3Sn in a Sn matrix. Plate-like ε-Ag3Sn intermetallics were observed for all four alloys. Solder alloys SAC105, SAC205 and SAC305 showed a similar microstructure, while SAC405 displayed a fine microstructure with intermetallic phases dense within the Sn matrix. Originality/value Currently, low-silver content SAC alloys are being investigated due to their lower cost, however, the overall reliability of an alloy can be greatly affected by the microstructure and this should be taken into consideration when choosing an alloy. The size and number of Ag3Sn plate-like intermetallics can affect the reliability as they act as a site for crack propagation.
KW - Alloys
KW - Reliability management
KW - Solder
UR - http://www.scopus.com/inward/record.url?scp=51349121097&partnerID=8YFLogxK
U2 - 10.1108/09540910810902651
DO - 10.1108/09540910810902651
M3 - Article
AN - SCOPUS:51349121097
SN - 0954-0911
VL - 20
SP - 3
EP - 8
JO - Soldering & Surface Mount Technology
JF - Soldering & Surface Mount Technology
IS - 4
ER -