Bob,
As was said, it all depends.
However, some really generic numbers for silica, or oxide filled adhesives
are 40-100 PPM/°C <Tg, and 120-300 PPM/°C >Tg. Depending on the material,
the Tg can be all over the map. Need your specific material to know for
sure.
Steve
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner
Sent: Friday, September 14, 2012 5:02 PM
To: [log in to unmask]
Subject: Re: [TN] Broken Vias
Hi,
Does anyone know about the TCE of via plug material? I am trying to get a
material number of what was used. This was the first board we ever ran with
via plugging but I would think that is a well-known process?
Bob K.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jason Zhao
Sent: Friday, September 14, 2012 12:52 PM
To: [log in to unmask]
Subject: Re: [TN] Broken Vias
Bob,
Xsection will show you where the opens occur. Possibilities are: copper
plating folds; thin copper; corner crack; post separation; separation due to
no wraparound; etc. Then we can determine the root causes from there (there
are too many to guess now). Looking forward to some pictures.
Best Regards
Jason Zhao
VP of North America Operations
Sunshine Circuits
3400 Silverstone Drive, Suite 139, Plano, TX 75023 US Cell 510-468-4412,
China Cell 131-62722392 www.sunshinepcbgroup.com
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner
Sent: Friday, September 14, 2012 10:18 AM
To: [log in to unmask]
Subject: [TN] Broken Vias
Hi,
A small company in the area has a board with two very expensive parts, about
$3K each part. They built 30 boards and had lots of open via connections.
They are getting cross sections now on some bad vias. In addition to many
bad vias there was some board warp. Sorry I don't have any hard numbers on
bad via counts or warp.
These were 10 mil holes in .062 material, a 6:1 aspect ratio, should be
easy. Vias were plugged and plated so they could be used as flying probe
test points.
After reflow assembly the boards were run on a wave machine using a mask
where about 25% of the board was exposed to the wave. Everything lead free.
Question:
Can folks suggest lists of items we can check, measure or inquire into? Any
guesses or ideas as what might be going on?
Thanks,
Bob K.
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
|
