Steve,
Have you considered a adhesiveless material such as Dupont PARALUX. I
think the part number is AP9121 but I could be wrong. The IPC
specification is IPC-4101b/41. By the way, it's Tg is about +250
Celsius. By the way, I think you are answering you own question
regarding exceeding the Tg of the material and seeing failed vias as a
result..
Dave Connitt

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Kelly
Sent: Tuesday, December 22, 2009 11:26 AM
To: [log in to unmask]
Subject: [TN] Via fill on flex

Hi All,

We have a 6 layer flex that my customer has to thermal cycle at
temperatures beyond the rated Tg's of the material- the end use
environment is about as bad as it gets. After repeated thermal cycles we
start to see cracks develop in the glue layer used to bond the
adhesiveless layers together. Will some kind of via fill help this
issue?

Thanks in advance.

Regards Steve Kelly





Steve Kelly (PLEASE NOTE NEW E-MAIL ADDRESS)

(416) 750-8433 (work)

(416) 750-0016 (fax)

(416) 577-8433 (cell)




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