Peer-Reviewed Journal Details
Mandatory Fields
Coyle, R; Osenbach, J; Collins, MN; McCormick, H; Read, P; Fleming, D; Popowich, R; Punch, J; Reid, M; Kummerl, S
2011
January
Ieee Transactions On Components Packaging And Manufacturing Technology
Phenomenological Study of the Effect of Microstructural Evolution on the Thermal Fatigue Resistance of Pb-Free Solder Joints
Published
()
Optional Fields
Reliability testing Soldering LEAD-FREE RELIABILITY ALLOYS SIZE
1
1583
1593
Unlike SnPb solders, the thermal fatigue reliability of the Sn-Ag-Cu (SAC) solders is believed to be influenced significantly by both the initial and evolving microstructures. This paper presents a phenomenological study of the relationship between the initial SAC solder joint microstructure, the evolving microstructure, and the thermal fatigue performance measured by accelerated temperature cycling (ATC). To reflect the board assemblies that are in field use, commercial surface mount components with multiple geometries and materials and from different package assemblers were joined to the board with different lead free SAC alloys. The initial microstructures of the board level solder joints were altered in a variety of ways including: 1) varying the solder joint cooling rate; 2) varying the number of solder reflow exposures; and 3) exposure to different isothermal temperature exposures. In all cases the solder joint microstructure was exposed to one or more of these treatments prior to exposure to temperature cycling. In addition, some of the test boards were exposed to different cycling dwell times to determine if the microstructural evolution that occurred during ATC testing effected the respective characteristic lifetimes of the joints. The microstructural evolution was tracked and characterized with optical metallography and scanning electron microscopy. These results could have practical implications in terms of limiting the ability to develop acceleration factors and effective strain-based models for predicting Pb-free solder joint life.
10.1109/TCPMT.2011.2140109
Grant Details