ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The formation and evolution of the intermetallic compound (IMCs) between SnAgCulead-free solder and Cu substrate, after isothermal aging at 150°C for 24, 48, 120, 240 and 480hours, were studied. Scanning electron microscope (SEM) was used to observe the microstructureevolution of solder joint during aging. The IMC phases were identified by energy dispersive X-ray(EDX). The results showed that IMCs layer of Cu6Sn5 was formed at the interface of solder and Cuduring reflowing. With the increase of aging time, the grain size of the interfacial Cu6Sn5 increasedand the morphology of the interfacial Cu6Sn5 column was changed from scallop-like to needle-likeand then to rod-like and finally to particles. At the same time, the rod-like Ag3Sn phase formed atthe interface of solder and the IMCs layer of Cu6Sn5 with the aging time increased. In addition,large Cu6Sn5 formed in the solder with the aging time increased. The tensile strength was measuredfor the solder joints. The results showed that the tensile strength increases slightly at beginning andthen decreases with the aging time. SEM was used to observe the fracture surface and it showed thatthe fracture position moved from solder matrix to the interfacial Cu6Sn5 IMCs layer with the agingtime increased. The weakening of the solder matrix is caused by the coarsening of the eutecticsolder structures. The weakening of the interfacial IMCs layer is caused by the evolution ofmorphology and size of the interface Cu6Sn5 layer
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/55/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.353-358.2928.pdf
Permalink