Electronics Forum | Thu Nov 03 13:35:46 EST 2005 | Amol
the copper forms intermetallics with tin to get Cu3Sn and Cu6Sn5. thus intermetallics formation consumes Cu and depends upon the cooling rate, faster the cooling rate, lesser the intermetallic formation
Electronics Forum | Wed Sep 03 07:43:13 EDT 2008 | davef
What do you mean by a "few micron thick"? IMC thickness pre-cycling (NEMI Lead-free) * Cu3Sn: 3um [118 uin] * Cu6Sn5: 1um [40 uin]
Industry News | 2012-01-13 12:42:50.0
Nihon Superior Co. Ltd., a supplier of advanced soldering materials to the global market, announces that Senior Technical Advisor Keith Sweatman will present “The Stability of Cu6Sn5 in the Formation and Performance of Lead-free Solder Joints” at the SMTA Pan Pacific Microelectronics Symposium.
Industry News | 2012-02-07 16:20:22.0
Nihon Superior announces that its Senior Technical Advisor Keith Sweatman will present the paper titled “Effect of Cooling Rate on the Intermetallic Layer in Solder Joints” at the upcoming IPC APEX Expo.
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.
Technical Library | 2013-02-28 17:14:36.0
While it has long been known that the Cu6Sn5 intermetallic that plays a critical role in the reliability of solder joints made with tin-containing alloys on copper substrates exists in two different crystal forms over the temperature range to which electronics circuitry is exposed during assembly and service, it has only recently been recognized that the change from one form to the other has implications for solder joint reliability. (..) In this paper the authors report a study of the effect of cooling rates on Cu6Sn5 crystals. Cooling rates from 200°C ranged from 10°C/minute to 100°C/minute and the effect of isothermal ageing at intermediate temperatures was also studied. The extent of the phase transformation after each regime was determined using synchrotron X-ray diffraction. The findings have important implications for the manufacture of solder joints and their in-service performance... First published in the 2012 IPC APEX EXPO technical conference proceedings....
SMTnet Express February 28, 2013, Subscribers: 26214, Members: Companies: 13305, Users: 34373 Effect of Cooling Rate on the Intermetallic Layer in Solder Joints While it has long been known that the Cu6Sn5 intermetallic that plays a critical role
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
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(from plating) and to the pad (from hot air leveling or other pcb solder-coating method), an intermetallic of tin-copper forms. This is typically Cu6Sn5 or Cu5Sn6 and this intermetallic is what causes the solder to adhere to the copper pads and leads
Surface Mount Technology Association (SMTA) | https://www.smta.org/knowledge/proceedings_abstract.cfm?PROC_ID=5246
cracking that is often observed in interfacial Cu6Sn5 when Ni is not present. In this paper we will provide an overview of the results of recent real time observations of the polymorphic transformation using high voltage transmission electron microscopy (HV-TEM
