Is that possible for both solder joint bridging and open solder joint defect occur in the same BGA (Ball Grid Array) or CSP (Chip Scale Package) device?
It is rare to observe both solder joint bridging and open solder joint defects simultaneously in a BGA device under normal circumstances, but it is still possible. In cases where the BGA substrate and PCB exhibit a significant deviation in CTE (Coefficient of Thermal Expansion), the BGA substrate may deform with a concave smile-up curve, while the PCB may deform with a convex cry-down curve due to longer TAL (Time Above Liquidus) or significant temperature variation between the upper and lower heaters in the reflow oven.
Recently one of my top manager ask to mount the shielding-can or call shielding-cover directly on the Printed Circuit Board to instead of mount the shielding-clip or call shielding-frame on the board first then cover the shieling-can. He said this “new process” is more cheap and can reach better RF (Radiation Frequency) performance. Also most of current popular cell phone board apply this solution.
