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 | Thu Sep 21 21:00:21 EDT 2000 | Dave F
Well, I'm going to assume you: * Have a nichel barrier between the copper on your board and the gold / solder solution * Use a lead / tin near euthectic solder If so, I pick "C" - It doesn't matter. When concerned about copper tin intermetallics, t
Electronics Forum | Wed Oct 10 16:16:15 EDT 2001 | lisa
Hello all, I'm looking for some advice on inter-metallic formation. I have some circuit board finished with Immersion Tin, Immersion Silver and OSP. They have been reflowed with solder past and components,the joints look good. What can I expect fo
Electronics Forum | Thu Mar 28 14:04:16 EST 2002 | davef
Intermetalic Layer (IL). A compound formed at the interface of two different metals, whose atoms have an extremely high natural attraction for each other, so high, that they do not bond to other elements by any other means. Also, intermetalic compo
Electronics Forum | Wed Sep 10 12:56:09 EDT 2003 | davef
Intermetallic compounds [IMC]: * Form during the alloying process of some metals. In soldering these are Sn, Ni, Ag, Cu, Au. * Do not accept solder. * Increase in depth in logarithmic proportion to both time and temperature. [So during the solder
Electronics Forum | Thu May 18 11:27:36 EDT 2006 | patrickbruneel
I'm not on the production floor on a daily basis like the other guys here but here's my 2 cents: With a Ni/Au plating the inter-metallic that needs to be formed is Ni/Sn. Ni/Sn inter-metallic requires higher peak assembly temperature and a longer dwe
Electronics Forum | Thu Sep 07 08:50:45 EDT 2006 | Grant
Hi, We have seen a slight rise in failures in a product, and on investigation, the BGA ball has cracked off the PCB. It's below the intermetalic layer in the ball. Reflow otherwise looks good, and the raw components are clean. I am wondering what c
Electronics Forum | Tue Jul 15 16:30:57 EDT 2008 | boardhouse
Hi Aj, Recommended Immersion gold thickness would be 3-5 Micro inches over 140 -200 micro inches of Nickel. Thicker Immersion gold than 5 micro inches can cause solder joint embrittlement. Gold readily dissolves in molten solder and will be present
Electronics Forum | Thu Sep 17 04:48:51 EDT 2009 | grahamcooper22
The colour you see on the pads is tin/copper intermetallic layer. In your reflow the immersion tin coating and the copper pad underneath react to form in intermetalic layer. The effect is worse the hotter the pcb or area of the pcb gets. In IR reflow
Electronics Forum | Fri Feb 15 15:37:35 EST 2019 | emeto
Hello, I have a capacitor that doesn't form intermetallic joint with SAC 305 solder paste.The board is ENIG. Solder melts and forms good intermetallic joint with the PCB finish. However, capacitor can be removed with physical force - it looks like a
