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Trouble reworking Xilinx 4044XL BGA chip

John Dwinell


Trouble reworking Xilinx 4044XL BGA chip | 17 January, 2001

Hello All,

I am looking for any insight RE: reworking the Xilinx 4044XL 40x40 BGA chip. A customer of mine has no trouble removing it, however, when installing with their BGA rework station, the corner solderballs consistently collapse. Has anyone run into this before with a similar chip? If so, any input would be greatly appreciated.



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Trouble reworking Xilinx 4044XL BGA chip | 17 January, 2001

The corner balls are supposed to collapse, but at roughly the same time as the other balls collapse. Also, those balls are located in the place that isthe easiest to get hot. Think about cranking-up the bottom heat, waiting, and slowing down the profile. Make sure your profiling in the middle of an inner row.

Earl Moon wrote an excellent article on reworking BGA in a SMTnet Newsletter

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Casey Scheu


Trouble reworking Xilinx 4044XL BGA chip | 29 January, 2001

The solder ball collapse is associated with overheating. Of coarse there's no problem taking it off, your nuking it. The problem, as your aware, is in the replacement. The machine your using is overdriving the process. The key to this repair is in the preheat. The entire board should be preheated to at least 140c befor the reflow is started. There are many other issues related to this repair. I've even seen the chip itself warp. Because of the package design obtaining a proper rework profile can be extramlly difficult w/ conventinal equipment. You need a machine that has a large preheater. I can fix this chip 99.9% of the time. It's all in the process. Please check out this link. It's what you need to do the job. If you have any questions please feel free to call me directly at 305-451-4722.


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