Hi Steve,
My guess is that that although there is only limited compatibility between
the dry film solder resist and alkaline cleaning chemistry (as Steve Mikell
suggests), the cleaning time will probably be too short for serious
degradation ofthe soldermask. Problems may occur however when the dry film
isn't fully cured, or when the board vendor treats the boards with
incompatible chemistries after solder resist application (I've heard that
immersion gold baths are famous for this, I assume goldfinger-plating baths
can be agressive too ?) .
Good luck !
Daan Terstegge
----- Original Message -----
From: Stephen R. Gregory <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, August 31, 1999 10:10 PM
Subject: Re: [TN] Was: Blister Pictures, Now: "I got dem' ol Dry-film blues
baybuh"
> Hey Stephen!
>
> (Cool name BTW...hehehe) Well, I did your test with the same board that I
> started with, so it's been through one thermal excursion and one Kyzen
> cleaning...couldn't see anything wrong after that. So I put it in the
cleaner
> again and put it under a scope again, started seeing some slight lifting
on
> the vias...hmmmmm (I says to myself)...
>
> So I put it in the MCS one mo' time, and guess what? "Oh lawdy, lawdy! I
got
> dem' ol flaking dry-film mask blues baybuh!" Stuff was flaking off all
over
> the place! Hmmmmm (I says to myself again) because the customer says;
"Hey,
> you got three other boards that you guys build that we've spec'd out with
> dry-film mask, (and they all come from the same fab vendor) why ain't ya
> having troubles with those boards?
>
> That's a real good question (I says to myself again...I've started talking
to
> myself a lot lately, hehehe) So I went and found the boards in question,
and
> it's obvious that there have been two different dry films used just from
the
> visual appearance between the boards.
>
> SO, my next task is to find out what precisely was used on these boards...
> Supposedly, all of the boards use DynaChem masks. There is one difference
on
> the board that has the flakey mask that the rest don't, and that is that
> board is a PCI card that has gold plated fingers, the other three don't
have
> anything gold plated on them at all. Does that have anything to do with
> anything? Just asking stupid questions is all...
>
> -Steve "Blues Bro" Gregory-
>
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