Wee Mei:
In my opinion it is the same problem. The board was cleaned but
there was an area where contamination was left or it was splashed with a
liquid after it was cleaned. We had a similar problem, a board was left
immersed in alcohol accidentally for a little too long for that board and
the solder mask lifted off the board. I have tried to repeat the same
problem by leaving boards for much longer time in alcohol. So far it has
not happened. It has to be a bare board problem. In a way it is better that
it happens in house and scrap the boards than it happens out in the field.
Regards,
Ramon
> -----Original Message-----
> From: Lum Wee Mei [SMTP:[log in to unmask]]
> Sent: Tuesday, January 13, 2004 6:26 PM
> To: [log in to unmask]
> Subject: [TN] Snake Board Part II?
>
> Hello,
>
> While Steve had your attention to his "Snake Board", what is the likely
> casue on my soldermask problems?
>
> Thanks and regards,
> Wee Mei
>
> Steve Gregory wrote:
>
> >Hi All!
> >
> >Back on January 6, Wee Mei had asked me to post some pictures for him,
and
> >then he posted the question below.
> >
> >Well, I've been gone since the beginning of the week (up in nice, warm,
> >Burlington, Ontario Canada), and am just now getting around to posting
his pictures
> >for him. You can see the pictures at: http://www.stevezeva.homestead.com
> >and look at "soldermask 1-3"
> >
> >-Steve Gregory-
> >
> >
> >
> >>----- Original Message -----
> >>From: "Lum Wee Mei" <[log in to unmask]>
> >>To: <[log in to unmask]>
> >>Sent: Tuesday, January 06, 2004 1:45 AM
> >>Subject: [TN] Solder Mask Defects - What casue it.
> >>
> >>
> >>
> >>
> >>>Hello,
> >>>
> >>>I have asked Steve to download the picture at his site. Once it ready,
> >>>can someone take a look and give me your opinion what is the likely
cause.
> >>>
> >>>Background : The board was partially mounted previously. It come back
> >>>to mount the remaining 6 chips. The board was washed as per normal with
> >>>Ensolv and assembled immediately. As the operator solder the chip, she
> >>>noticed scale-like defects appearing on the soldemask around the whole
> >>>stretch of the solder pads. The defects are more prominent on the left
> >>>side compare to right of the chip. This is repeated for the rest of the
> >>>5 chips.
> >>>
> >>>Being naughty, she touched the board surface with the soldering iron
tip
> >>>and found on the same spot the same defect appearing.
> >>>
> >>>One more information : defects found on these 2 boards have a much more
> >>>rough surface compare to other pieces within the same batch.
> >>>
> >>>How the information is sufficent for you to provide opinions.
> >>>
> >>>Thanks and regards,
> >>>Wee Mei
> >>>
> >>>
> >
> >
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