Electronics Forum | Tue Oct 17 15:31:29 EDT 2006 | TM
I've got some MELF packages that reflow and connect but later fall out of the solder pretty easily. We are not using epoxy but, the parts have fillets per IPC standards. We have not looked at cross-sectioning for IMC and don't plan to at the moment
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]
Electronics Forum | Sun Mar 31 00:42:09 EDT 2013 | dhanish
Why we cannot run Pb Free BGA with Sn/Pb process but we can run high temp BGA(90/10) with Sn/Pb? Both require high temperature to form the IMC.Why there is a difference in the reliability?
Electronics Forum | Fri Oct 01 02:46:47 EDT 2021 | sn
Thanks, Evtimov. In terms of mechanical drop performance, can we conclude that the higher Ag alloy will have poorer drop shock performance relatively compare to those with lower Ag? The Ag3Sn is a good IMC for welding strength?
Electronics Forum | Fri Sep 24 10:57:18 EDT 1999 | Earl Moon
| Hi Folks: | | We've been having bridging problems on our fine-pitch QFP's, despite thorough inspection of paste height, volume, and placement accuracies....profiles look good also. | | The bridging is happening after coming out of reflow...one la
Electronics Forum | Thu Dec 08 07:55:16 EST 2005 | davef
Your understanding of the situation is correct. In both cases, you solder to the nickel. The gold [Au] protects the nickel from oxidation. When soldering, the gold moves into solution in the solder and forms an intermetallic compound [IMC] with th
Electronics Forum | Mon Jun 12 22:00:51 EDT 2000 | Dave F
Could be. What are your profiles? 2) Au finish fail => Could be, but that the connections can be made with hand soldering makes this a low probability cause, assuming the activity of the flux used in hand soldering is not significantly different fr
Electronics Forum | Mon May 20 10:49:12 EDT 2002 | geoff_goring
Are we saying then that IMC can occur at the solder / Cu pad join on the PCB when finished assembled? In our case we are being told that this process is starting before assembly. Is it fundamentally the same thing. i.e. will the Tin diffuse with th
Electronics Forum | Fri Sep 28 16:49:48 EDT 2007 | davef
good * No IMC => bad Intermetallic growths are diffusion limited, and therefore the thickness of the intermetallic is given by: z^2 = (Do)(t)exp[-Q/RT] Where Do (m^2 s-1) is the diffusion coefficient, T(�K) is the temperature, Q (J mol-1) is the act
Electronics Forum | Wed Sep 03 16:59:13 EDT 2008 | glennster
At a former employer we required HASL thicknes to be a minimum of 0.75 micron (30 microinches), as measured at the thinnest point on any given pad. This would generally assure a minimum 1 year solderability shelf life. Usually when we saw a soldera
