Electronics Forum | Thu Aug 24 13:20:24 EDT 2000 | Murad Kurwa
One of our divisions is having this problem: - De-wetting on the smt pads and componenent termination on the bottom side after top side procssed through reflow. Board finish is immersion silver. ? Any recommendation on what we should check & verify
Electronics Forum | Fri Jun 16 07:46:42 EDT 2006 | davef
We use HASL and immersion silver, depending on the board design.
Electronics Forum | Thu Feb 19 12:35:13 EST 1998 | Earl Moon
| | We are currently investigating alternatives to HASL for circuit boards with 20 mil pitch smt pads and below. If you have experience with this product or simular immersion tin products with respect to manufacturing or assembly I am very interest
Electronics Forum | Wed May 16 15:40:56 EDT 2012 | davef
Here's some notes from a Bob Willis presentation Assembly of Flexible Circuits with Lead-Free Solder Alloy [Bob Willis leadfreesoldering.com] * Flexible Circuit Construction ** Base Material - 0.05mm Copper 18/18 um ESPANEX from Holders Technologies
Electronics Forum | Tue Jul 06 11:58:44 EDT 2010 | baildl632
What type of finish are the PCB's? HASL, tin immersion, silver immersion,........we've seen all the above problems with HASL finished boards. Usually either reheating w/ a soldering iron or "burnishing" with a scotch brite pad has worked for us.
Electronics Forum | Thu Apr 27 11:36:53 EDT 2000 | PeterB
Russ, We also use 'immersion silver' and have not had any impact on our processes. In fact there are a number of benefits i.e very flat pads (as good as electroless nickel/immersion gold but much cheaper and less unfriendly to the environment), good
Electronics Forum | Sat Feb 16 20:13:45 EST 2019 | sarason
Your silver immersion layer is dissolving in the solder. I presume this is what is meant to happen. But with copper tracks underneath that should be fine. Does your SAC305 cover all of the pad. If so no problem. If not then you will need to flux your
Electronics Forum | Tue Sep 09 15:22:39 EDT 2003 | gdstanton
Anyone have any experience with immersion white tin over copper plating? We are seeing opens develop under BGAs after we bake and conformal coat. And when we lift the parts the pads are 60% of the original size. Need some advice on possible causes
Electronics Forum | Fri Aug 26 09:57:21 EDT 2005 | russ
The Immersion gold is not a problem with BGAs specifically but "black pad" which can be present anywhere. The unfortunate thing with BGAs is you cannot see it. Personally I hate white tin. It is okay for single sided boards running no-clean, but c
Electronics Forum | Tue Jun 08 08:27:14 EDT 2004 | michaeljm
I would like to see the report from MacDermid. We have samples of ag boards in which the underside of PCB pad has been plated between the PCB laminate and pad.
