Title :
Grain boundary sliding in surface mount solders during thermal cycling
Author :
Lee, Seong-Min ; Stone, Donald S.
Author_Institution :
Dept. of Mat. Sci. & Eng., Wisconsin Univ., Madison, WI, USA
Abstract :
The growth of fatigue cracks in near-eutectic, surface-mount solder joints during cyclic, thermal displacement-controlled loading is reported. Ceramic leadless chip carriers (LLCC) are subjected to thermal fatigue with a frequency of 1/hr and over two ranges of temperature: -36°C to 125°C and -20°C to 75°C. Surfaces and cross-sections of the solder joints are inspected using scanning electron microscopy. Individual grains (colonies of lamellae and globulae) are found to slide relative to one another during thermal cycling. Sliding causes fatigue cracks to initiate at the surface
Keywords :
environmental testing; fatigue cracks; lead alloys; life testing; soldering; surface mount technology; tin alloys; -36 to 125 degC; 0.00028 Hz; Pb-Sn solders; ceramic leadless chip carriers; colonies of lamellae; fatigue crack initiation; globulae; grain boundary sliding; growth of fatigue cracks; near eutectic solder joints; ranges of temperature; scanning electron microscopy; solder joint cross-sections; surface mount solders; surface-mount solder joints; thermal cycling; thermal displacement-controlled loading; thermal fatigue; Ceramics; Electrons; Fatigue; Frequency; Grain boundaries; Lead; Soldering; Surface cracks; Temperature distribution; Thermal loading;
Conference_Titel :
Electronic Components and Technology Conference, 1990. ., 40th
Conference_Location :
Las Vegas, NV
DOI :
10.1109/ECTC.1990.122233
