Electronics Forum | Fri Aug 06 08:38:25 EDT 2004 | Bob R.
You don't mention the board surface finish, but BGA's on NiAu are prone to brittle fracture in the Sn-Ni intermetallic on the board side of the joint. You may not be able to see it visually, but it would show up in a cross-section. In-circuit test
Electronics Forum | Fri May 31 10:15:30 EDT 2019 | davef
Major sources of crack in the solder connection after thermal cycling are: * Thermal heating caused by differences in thermal expansion between the board and the component * Lead-free solder is more rigid and brittle than eutectic solder in simila
Industry News | 2011-02-24 20:35:03.0
The SMTA is pleased to announce the program for the 2011 International Conference on Soldering and Reliability being held May 3-6 in Toronto, Ontario, Canada.
Industry News | 2013-02-14 08:18:47.0
IPC – Association Connecting Electronics Industries® has announced the winners of the Best U.S. and International Papers of IPC APEX EXPO® 2013
Technical Library | 2021-01-13 21:34:29.0
Package-on-Package (PoP) is a popular technology for fabricating chipsets of accelerated processing units. However, the coefficient of thermal expansion mismatch between Si chips and polymer substrates induces thermal warpage during the reflow process. As such, the reflow temperature and reliability of solder joints are critical aspects of PoP. Although Sne58Bi is a good candidate for low-temperature processes, its brittleness causes other reliability issues. In this study, an in-situ observation was performed on composite solders (CSs) made of ...
Technical Library | 2019-06-20 00:09:49.0
It is well known that during service the layer of Cu6Sn5 intermetallic at the interface between the solder and a Cu substrate grows but the usual concern has been that if this layer gets too thick it will be the brittleness of this intermetallic that will compromise the reliability of the joint, particularly in impact loading. There is another level of concern when the Cu-rich Cu3Sn phase starts to develop at the Cu6Sn5/Cu interface and an imbalance in the diffusion of atomic species, Sn and Cu, across that interface results in the formation at the Cu3Sn/Cu interface of Kirkendall voids, which can also compromise reliability in impact loading. However, when, as is the case in some microelectronics, the copper substrate is thin in relation to the volume of solder in the joint an overriding concern is that all of the Cu will be consumed by reaction with Sn to form these intermetallics.This paper reports an investigation into the kinetics of the growth of the interfacial intermetallic, and the consequent reduction in the thickness of the Cu substrate in solder joints made with three alloys, Sn-3.0Ag-0.5Cu, Sn-0.7Cu-0.05Ni and Sn-1.5Bi-0.7Cu-0.05Ni.
Lyra Reflow Oven is a soft soldering that realizes the mechanical and electrical connection between the solder ends of surface mount components or the pins and the printed board pads by remelting the solder paste pre-distributed on the printed board
SMTnet Express, June 20, 2019, Subscribers: 32,068, Companies: 10,815, Users: 24,854 Dissolution in Service of the Copper Substrate of Solder Joints Credits: Nihon Superior Co., Ltd. It is well known that during service the layer of Cu6Sn5
| https://www.eptac.com/faqs/ask-helena-leo/ask/problems-with-pcb-micro-voiding
. The true root cause is still under investigation, but a Kirkendall voiding mechanism may play a part. These voids can affect solder joint reliability, particularly in instances when brittle fracture is initiated within the IMC during drop or mechanical hock to the solder joint
| http://etasmt.com/cc?ID=te_news_bulletin,23575&url=_print
. One of the unfortunate properties of the intermetallic is that it is far more brittle than the tin-lead solder or the copper (or other metals involved
