I have a big problem with soldering uP QFP144 package.All components in PCB are small, only this chip is big and I can't make good temperature profile.Solder joints of other components are shining and with good wetting, but in QFP leads solder joint look poor and grey.I think, the problem is in the profile, try several profile but nothing.Our reflow have 9zones top znd bottom.Tne paste is kester R256 - Pb.If somebody can halp me I will be very grateful.
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