Hi all,

We are designing a 9 pin BGA into a board and having some board issues. The pitch of the part is .5mm and the part is a fet (higher power needs). The data sheet recommends a .25mm (.010 mil) pad which we have done, but we are having problems with the part twisting a bit on placement (requiring rework after reflow). After the initial board build, we adapted a thinner solder paste and tied the pads on opposite sides of the part (R & L) to vias to add some extra pull to keep the device in place. That build was better, but still not as accurate as we would like because of the solder mask opening size (+.004 overall) and SM placement tolerance is so huge compared to pad size... only .010.

SO..... my question is.... Are any others using .5 mm pitch BGAs, and if so, what are you doing to make them assemble properly.

Thanks,
Susy

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