Good morning TechNet,

     We have recently started using BGA's in our prototype assembly lab. We
     can successfully place and reflow the component (thermal cycle 1 using
     a forced air convection oven), remove the component (thermal cycle 2
     using a ChipMaster rework station + bottom heat), and place and reflow
     a new component (thermal cycle 3 using the ChipMaster). Our problems
     start when we try a 4th thermal cycle to remove the component again.
     We are lifting pads during the site preparation using a thin solder
     wick. Is there a limit to the # of thermal cycles on BGA land patterns
     or are we doing something wrong?. Is solder wick appropriate for
     leveling solder?  Are there repair kits available to fix lifted pads?
     Our boards are FR4 W/ 1/2 oz. copper. We are using a mix of PBGA's and
     TBGA's. The TBGA's (which require a little more heat for a longer
     duration) seem to be lifting the pads more readily.
                                All comments would be greatly appreciated,
                                        [log in to unmask]

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