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 | Tue Nov 07 10:25:19 EST 2000 | Thomas Ballhausen
Thank you for your kind contribution and efforts in helping me. I just found out we have been talking different units; my microns were micro meter ...? So, let me get things right now: the substrate supplier confirmed the following data: Cu foil +
Electronics Forum | Fri Jan 19 17:43:30 EST 2001 | 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 | Mon Sep 17 02:56:40 EDT 2001 | mugen
Hi, (me been absent for some time...) Are your brds confirmed HAL over copper? (check out what Dave F mentioned abt possible root causes) or are the brds HAL over nickle? (shd be no problem here, if so?) or are the brds strictly nickle plated pads?
Electronics Forum | Wed Jun 25 12:08:53 EDT 2003 | russ
I battle this all the time, I don't believe that it is the "gold corner" that is causing the problem but something with the PCB layer makeup (copper planes, or bottom side components, etc.). It could also be the nozzle you are using has a "hot spot/
Electronics Forum | Mon Jan 24 06:19:04 EST 2011 | fönsi
Hello! I've had the same problem about one Jear ago. We had exessive building of voids in the solder joints. I recomment to take a pincer to break off some of the components. If the solder joint is good, the copper pad will stay at the solder joint
Electronics Forum | Fri May 13 14:08:39 EDT 2011 | eezday
This appears to be black-pad and is often the result of using specs that call for gold plating that is too thick. The black pad is corrosion that is created between the gold and electroless nickel during the gold plating process. This is counter in
Electronics Forum | Mon May 22 15:46:49 EDT 2006 | adlsmt
Grant has a good idea, we started that way also. We made a tank out of stainless steel with copper tube coils about 18" off the bottom. Circulate cold water through the tubes to condense the vapor to keep the loss down. We used electric burners under
Electronics Forum | Fri Sep 14 15:31:02 EDT 2001 | davef
How in earthly heaven would someone else have a report analyzing the defects on your boards? Among the good failure analysis labs that can assess situations like yours are: * Robisan Laboratory 6502 East 21 St Indianapolis, IN 46219 317-353-6249 fax
Electronics Forum | Thu Jan 18 21:52:24 EST 2001 | arul2000
>>>>Dave, The BGA substrate surface finish is NiAu, while the PCBA pad surface is HASL. The solder ball composition is SnPb 63/37 and the solder paste used on the PCBA is also the same but with 2% Silver.>>> Dave, sorry I don't have the picture with
