Subject: | |
From: | |
Reply To: | TechNet E-Mail Forum. |
Date: | Thu, 8 Apr 1999 15:25:22 -0700 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Bill-
I agree with Steve Gregory. If you had a history of moisture absorption
problems then I would. Bear in mind that polyimide generally saturates
at 3-5% water vapor at STP. Thus, even a factory floor at 50% RH will
allow for the poly-i to saturate eventually. Hopefully, your are getting
the boards dry-packed, and they are not opened from the dry pack until
just prior to stuffing. If you have the boards opened for any
appreciable time before stuffing (say 3-4 hours) then you may want to
orchestrate an experiment to see what, if any, difference there is in
defectivity between a newly opened package and one that's been sitting
out for a couple of hours. ANything longer than 8 hours I would
definitely bake.
> Bill Davis, Ph.D.
> Diamond Multimedia Systems
> Senior Scientist
> Tel. 408.325.7868
> Cell. 408.888.5650
> e-mail: [log in to unmask]
>
>
-----Original Message-----
From: Mengers, William D. [mailto:[log in to unmask]]
Sent: Thursday, April 08, 1999 1:02 PM
To: [log in to unmask]
Subject: [TN] Baking of polyimide boards
Guys (and girls),
Can anyone tell me whether or not polyimide boards need to be pre-baked
before processing thru nitrogen reflow for solder melt? We are doing
it,
which of course means added expense. Is it really necessary? We bake
at
110 C for four hours. Is there evidence which suggests that it is
necessary.
Thanks for any replies,
Bill Mengers
Northrop Grumman Corp.
Baltimore, Md.
################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV
1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with
following text in the body:
To subscribe: SUBSCRIBE TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services"
section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or
847-509-9700 ext.312
################################################################
################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe: SUBSCRIBE TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################
|
|
|