Electronics Forum | Mon May 18 13:30:15 EDT 1998 | Earl Moon
| I'm reviewing my board fab spec. It calls for a minimum SnPb thickness of 50 microinches on HASL PWB's. I've looked at other specs that call out anything from 30 to 80 microinches, and others that just say the copper pad must be covered and solde
Electronics Forum | Thu May 21 09:54:07 EDT 1998 | Justin Medernach
| I'm reviewing my board fab spec. It calls for a minimum SnPb thickness of 50 microinches on HASL PWB's. I've looked at other specs that call out anything from 30 to 80 microinches, and others that just say the copper pad must be covered and solde
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
Electronics Forum | Tue Sep 02 09:32:45 EDT 2008 | eliezerk
In order to check pcb quality by HASL TIN thickness plating repeatability, looking for any specification for the above.
Electronics Forum | Wed Sep 03 11:47:08 EDT 2008 | realchunks
That sounds like a "Coupla microns thick" Dave.
Electronics Forum | Tue Sep 02 13:26:52 EDT 2008 | vladig
You should have a few microns of Sn on a board. Vlad
Electronics Forum | Wed Sep 03 12:35:47 EDT 2008 | realchunks
I believe Vlad is a sales person for Sentec.
Electronics Forum | Thu Feb 23 13:56:21 EST 2006 | slthomas
I have dealt with it before and usually it's consistent, so you use some simple math to work around the issues. Now, if you have so much variability between different locations on your board for resist thickness, HASL thickness, etc., that it fouls
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 | Wed Sep 03 07:36:39 EDT 2008 | vladig
That is why it has to be a few micron thick. Otherwise, it will form a layer of intermetallic which is extrremely difficult to solder to. Vlad
