Fig. 1. Schematic diagrams of (a) Cu/Ni/Sn-Ag microbumps with and without NCF trap, (b) daisy chain structure for EM test.
Fig. 2. As-bonded cross-sectional SEM images of Cu/Ni/Sn-Ag microbumps (a) with NCF trap and (b) without NCF trap.
Fig. 3. As-bonded SEM image of bottom Cu/Ni surface after solder etching of Cu/Ni/Sn-Ag microbumps with NCF trap.
Fig. 4. Resistance change versus time curve of Cu/Ni/Sn-Ag microbumps for 1.5 × 105 A/cm2 at 150℃: (a)with and without NCF trap, and (b) enlarged graph of Cu/Ni/Sn-Ag microbumps with NCF trap.
Fig. 5. Sequential SEM micrographs of Cu/Ni/Sn-Ag microbumps with NCF trap during current stressing at 150℃ , 1.5 × 105 A/cm2: (a) 10h, (b) 30h, (c) 60h.
Fig. 6. Sequential SEM micrographs of Cu/Ni/Sn-Ag microbumps without NCF tarp during current stressing at 150℃ , 1.5 × 105 A/cm2: (a) 10h, (b) 300h, (c) 600h.
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