Ted,

Is the package warping slightly and the corners turning downward?  Is the solder mask damaged at the corners due to the cleaning process?  Also, sometimes I have noticed that BGA replacement using a hot air rework station results in a lower package stand off distance if solder paste is not used (and possibly due to the slight downward hot air pressure pushing the package down).

joe

-----Original Message-----
From: Ted Kong [mailto:[log in to unmask]]
Sent: Monday, August 11, 2003 2:54 PM
To: [log in to unmask]
Subject: [TN] BGA bridging on corner pins only

Hi All at Technet Land,

Can someone explan why do I see bridgings only on the
corner pins during rework?  The package is a 1517 Pin
BGA and the rework was done on the SRT rework station
with only flux (No paste).  When I run the same board
and component through the reflow oven, I see no
bridging.  I tried lower the air flow and increase the
spacing between the board and the chimney, but neither
helped.  Any input is greatly appreciated.

Thanks all in advance.

Ted Kong

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