All good advice. Use the profiles well and be attentive to them. I still
like using hard balls in the corners when possible when using solder paste.
And on it goes.

MoonMan

----- Original Message -----
From: "Guy Ramsey" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, September 10, 2002 10:39 AM
Subject: Re: [TN] BGA rework - excessive collapsing


> Increases solder volume by about 10-20 percent in the package you are
> using. Increases likelyhood of bridging. Reduces effects of co-planarity
> problems. Will not increase clearance that much.
>
> Baking out the part was good advice. Verify temperature profile on the
> component, set ramp rate at 2?C per second. Don't exceed 220?C on the
> package, give the system time, stay above reflow for at least 30 seconds
> (measured under the part). And watch the cooling rate, not too fast on
> the way back down to 180?C.
>
>
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Peter Lee
> > Sent: Tuesday, September 10, 2002 10:35 AM
> > To: [log in to unmask]
> > Subject: Re: [TN] BGA rework - excessive collapsing
> >
> >
> > What would be the impact of using mini-stencil to paste the
> > board for BGA rework?
> >
> > Would it increase the chance of bridging or minimize it
> > through increased clearance and solder volume?
> >
> > Rgds,
> > Peter
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Earl Moon
> > Sent: Monday, September 09, 2002 4:53 PM
> > To: [log in to unmask]
> > Subject: Re: [TN] BGA rework - excessive collapsing
> >
> > With respect to PCB heating, some rework stations do a pretty
> > good job of preheating the board when the profile is
> > carefully planned and used. With that, the board most often
> > is not subject to warpage as you speak.
> >
> > Earl
> >
>
> >
>
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