It would be helpful to know the size of the device, I/O count, pitch and
the location of the "lifts" (corner or edge) and the specifics of the
substrates, package and mounting along with process specifics for starters. Also
is this a one time event or a recurring one? Right now it is just a
curiosity
As Werner has alluded with his comment that the picture is "less than
illuminating", it seems there are still "other shoes still need to drop".
Kind regards,
Joe
In a message dated 2/2/2010 5:13:11 P.M. Pacific Standard Time,
[log in to unmask] writes:
Hi Steve & All,
A 'mechanical hit' would not cause this. While the pic is less than fully
illuminating, I have seen similar 'buckle ups' with Pb-free
solders/soldering before.
We need to remember, that SAC is 40% stiffer than SnPb, has a higher yield
strength and creeps about a factor of 50 slower—it thus, becomes a
mechanically significant layer with a higher CTE than Cu and the PCB(x,y).
Werner
-----Original Message-----
From: Steve Gregory <[log in to unmask]>
To: [log in to unmask]
Sent: Tue, Feb 2, 2010 6:10 pm
Subject: Re: [TN] track lifting
Hi Pearl,
Here's your picture:
http://stevezeva.homestead.com/files/Track_Lifting.JPG
What I see in the picture is that BGA (it is a BGA isn't it?) was almost
ripped-off the board somehow.
The traces are stretched and the soldermask has been torn up from the
board.
The root cause is that something mechanically hit the BGA and ripped up
pads
and traces. Is there any other marks on the BGA?
Steve
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of pearl petras
Sent: Tuesday, February 02, 2010 5:13 PM
To: [log in to unmask]
Subject: [TN] track lifting
While we wait for IPC to set up a picture site, could I impose on Steve to
post another picture?
Any comments as to what could possibly be the root causes of this is much
appreciated.
Thanks so much
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