Technical Articles From Johns Hopkins Applied Physics Laboratory
Read technical articles about electronics manufacturing added by Johns Hopkins Applied Physics Laboratory
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2 technical articles added by Johns Hopkins Applied Physics Laboratory
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Effects of Tin Whisker Formation on Nanocrystalline Copper
Feb 13, 2023 | David M. Lee, Lesly A. PiƱol
Spontaneously forming tin whiskers, which emerge unpredictably from pure tin surfaces, have regained prevalence as a topic within the electronics research community. This has resulted from the ROHS-driven conversion to "lead-free" solderable finish processes. Intrinsic stresses (and/or gradients) in plated films are considered to be a primary driving force behind the growth of tin whiskers. This paper compares the formation of tin whiskers on nanocrystalline and conventional polycrystalline copper deposits. Nanocrystalline copper under-metal deposits were investigated, in terms of their ability to mitigate whisker formation, because of their fine grain size and reduced film stress. Pure tin films were deposited using matte and bright electroplating, electroless plating, and electron beam evaporation. The samples were then subjected to thermal cycling conditions in order to expedite whisker growth. The resultant surface morphologies and whisker formations were evaluated....
Effects of Tin and Copper Nanotexturization on Tin Whisker Formation
Aug 16, 2012 | David M. Lee, Lesly A. Piñol, PhD
First published in the 2012 IPC APEX EXPO technical conference proceedings. The physical mechanisms behind tin whisker formation in pure tin (Sn) films continue to elude the microelectronics industry. Despite modest advances in whisker mitigation techniqu...