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48 SMT Magazine • August 2015 Case 4 Package description: • PBGA • 578I/O • 35 x 35 mm • 1 mm pitch • SnPb • 0.6 mm ball diameter Case 4 is considered a medium size BGA. It also exhibited the highest degree of warpage of the cases presented in this paper. The device was reported to have 0.180 mm (7.1 mils) of negative warpage during reflow, resulting in substantial HoP defects during assembly. Figure 12 shows the 2D and 3D warpage measurement of the BGA. Interestingly, this part would fail the more recent JEDEC specification, (maxi- mum -0.14 mm allowable warpage), but would pass the JEITA specification of 0.22 mm maxi- mum allowable warpage. Case 5 Package description • FCBGA • 1932I/O • 45 x 45 mm • 1 mm pitch • Pb-free • 0.63 mm ball diameter While most of the cases presented in this pa- per are from production and factory HoP issues, case 5 is based on a specific test performed in col- laboration with a supplier on a large BGA. This test confirmed that a BGA, with 0.110 mm (4.3 mils) of negative warpage at reflow will gener- figure 12: 2D and 3D plot of the warpage measurement of the bga from case 4. figure 14: Warpage measurement of the bga from case 5 after the package improvement. figure 13: Warpage measurement of the bga from case 5 before the package improvement. WARPAGE ACCEPTANCE PROPOSAL continues FeAture