Keepout requirements for BGAs

Does anybody have information on the minimum spacing required between BGAs (i/o counts close to 696)to avoid damage during rework? Also, on the keep out requirements between CSPs (o.5 mm pitch); between CSPs and BGAs.

thanks in advance for your help changhong

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Chang Hong while developing our CSP rework process, we found a temperature spread of about 130C at a distance of approx 150 mils from the component edge. our nozzle had about 20 mils clearance from all sides of the component being reworked. depending upon the acceptable temperature gradients around the reworked area, and the heating strategy u use (direct ramp/3 stage dwell/traditional reflow) and the sequence of introducing the bottom/top heater, u cud get varying results for permisible keepout distance. Hope this helps. I would be glad to answer ur questions if any offline. Regards

Parvez

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