Impact of 10-Year Room Temperature Aging on SAC105
Authors: Deng Yun Chen, Subramani Manoharan, Patrick McClusky, and Michael Osterman Company: Center for Advanced Life Cycle Engineering (CALCE) Date Published: 9/22/2019
Abstract: Tin based solder on copper is well known to experience microstructural changes under accelerated temperature aging and result in fatigue life reduction and material properties change. Under elevated temperature aging, the intermetallic compounds (IMC), Cu6Sn5, Cu3Sn, and Ag3Sn, grow in size. As a result, effective modulus of the material reduces. Further, the temperature cycling reliability of lead-free (LF) solder joints often reduce with elevated temperature aging. However, the data exists in literature is limited to short term elevated aging (up to 1 year), which lacks validation for LF solder reliability and microstructure change after long term aging. This paper examines the temperature cycling reliability and microstructural change of SAC105 after 10 years of room temperature (~25°C). Printed circuit boards (PCBs) with chip resisters mounted with SAC105 were store for 10 years at room temperature. The microstructure of the solder joints will be examined and the material properties will be measured with nanoindentation. The result showed that 10 years room temperature aging had minimal impact on SAC105 microstructure and mechanical properties.
Lead-free, solder, aging, intermetallic, temperature cycling