Ratio of initializer?

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Thayer, Wayne
Sent: Tuesday, December 23, 2008 11:44 AM
To: [log in to unmask]
Subject: Re: [TN] Underfill, inhibition due to leftover activators in the
flux residue

I have been in underfill "hell" numerous times.

I still don't have a complete understanding of what makes it decide to not
cure properly, but moisture can be a big problem, as far as some of the
Henkel products go.  We are getting better results with extended bake cycles
to eliminate any moisture from the assembly.  This might have something to
do with your problem too:  Send it through the oven a number of times, and
each time it will be a bit drier.

I use mostly RMA flux and solvent clean.  I have mixed raw RMA flux directly
with the underfills we use and they seem to cure OK.  Only way I could get
the uncured goo witnessed sometimes on the production line was to literaly
mist it with water prior to attempting to cure.

Good Luck!

Wayne Thayer

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Dwight Mattix
Sent: Tuesday, December 23, 2008 11:46 AM
To: [log in to unmask]
Subject: Re: [TN] Underfill, inhibition due to leftover activators in the
flux residue

At 04:54 AM 12/23/2008, David D. Hillman wrote:
>But - if you have a BGA that is sufficiently large and has significant
>I/O, you are going to have some flux residue remaining under the
>component.

/heh    no kidding.

Phil,
This under a 7xxx series MSM?   Almost 700 pins on a .5mm or .4mm package?

You're going to love the the 8xxx series.  :-)    lol!

Merry Christmas,
dw

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