The 22nd Microelectronics Work Future Electronic Devices Technology in Cosmic Space and Lead-free Solder Joint Reliability Key Points (1) High Speed Solder Ball Shear Test (2) Relationship between Surface Finishing and Solder Ball Joint Reliability Yoshinori Ejiri Hitachi Chemical Co., Ltd.
Application of of Semiconductor Packages Digital Camera Digital Video Camera Mobile PC 1 Mobile Phone PCB SCP Car Airplane Aero Space
Increasing Density Decreasing Size TSOP (Thin Small Outline Package) CSP (Chip Scale Package) 2 Metal Lead (Fe/Ni Alloy) Solder Ball Assembly Area Below 1/2
3 Structure of of BGA Assembly Shock / / Vibration Stress Concentration Semiconductor Chip Gold Wire Package Substrate Printed Circuit Board Die Bonding Material Molding Material Solder Ball
Solder Ball Joint 4 Copper Pad Package Substrate Solder Mask Solder Ball Solder Ball Electroless Ni-P/Pd/Au
5 Surface Finishing for for Copper Pad Organic Solder Preservative (OSP) Immersion Ag Immersion Sn Electrolytic Au Electrolytic Ni / Electrolytic Au Electroless Ni / Immersion Au / Electroless Au (ENIGEG) Electroless Ni / Electroless Pd / Immersion Au / Electroless Au (ENEPIGEG)
High-speed Solder Ball Shear Test
6 High-speed Solder Ball Shear Test Shear Speed 0.5, 20, 200, 1000 mm s -1 High Speed Low High 10mm/s or more (JEDEC JESD22-B117A) Shear Tool Solder Ball Ductile Brittle Solder Mask Copper Pad Package Substrate
Shear Force (N) 35 30 25 20 15 10 5 0 0 200 400 600 800 Ductile Low Speed Displacement (μm) Shear Strength Solder<Interface Ductile 7 Solder Strength Interfacial Strength
Shear Force (N) Brittle High Speed 35 30 25 20 15 10 5 0 0 200 400 600 800 Displacement (μm) Shear Strength Interface <Solder Brittle 8 Interfacial Strength Solder Strength
High-speed Solder Ball Shear Test DAGE 4000HS Bond Tester (Dage Precision Industries, Ltd.) 9
Ductile Fracture Rate (DFR) / % 100 80 60 40 20 0 High-speed Solder Ball Shear Test 0.5 Low Speed 20 200 Ni-P/Au 1000 0.5 20 200 1000 Shear Speed/ mm s -1 Ni-P/ P/Pd/Au Ductile Brittle 10 Ni-P : 5 μm Pd : 0.1 μm Au : 0.3 μm
Relationship Influence between of Surface Surface Finishing Finishing and on Solder Ball Joint Joint Reliability Reliability
11 Experimental Condition Combination of Surface Finishing and Solder Ball Surface Finishing 1 OSP 2 OSP 3 E lytic Ni/Au 4 E less Ni-P/Pd/Au : Sn3.0Ag0.5Cu, Solder Ball SAC305 SnNiX (Sα) SAC305 SAC305 Evaluation Condition Reflow Cycles (Max Temp : 252 ) : 1, 3, 7 Aging Time(Temp : 150 ) : 100, 300, 500, 1000 h
Reflow Cycles 12 DFR / % 100 80 60 40 20 0 1 3 7 Reflow Cycles (Max Temp : 252 ) Shear Speed : 200 mm/s E less Ni-P/Pd/Au E lytic Ni/Au OSP-Sα OSP-SAC
Reflow Cycles 13 DFR / % 100 80 60 40 20 0 1 3 7 Reflow Cycles (Max Temp : 252 ) Shear Speed : 1000 mm/s E less Ni-P/Pd/Au E lytic Ni/Au OSP-Sα OSP-SAC
14 Reflow Cycles IMC Growth --Reflow Cycles SAC OSP Sα E lytic Ni/Au E less Ni-P/Pd/Au Solder Solder Solder Solder 1 Cu Cu Ni Ni-P 3 7 10 μm 5μm SJR Poor Excellent Excellent Excellent
Reflow Cycles --OSP-SAC Solder 15 Cu Cu 6 Sn 5 1 cycle 3 cycles Crack of IMC Crack Poor Reliability 7 cycles
Reflow Cycles --OSP-Sα 16 Solder Cu (Cu,Ni) 6 Sn 5 1 cycle 3 cycles Ni : Thin IMC Layer Better Reliability 7 cycles
Reflow Cycles --Ni/Au Solder 17 Ni 1 cycle 3 cycles (Cu,Ni) 6 Sn 5 7 cycles Thick IMC Poor Reliability
Reflow Cycles --Ni-P/Pd/Au 18 Solder Ni-P 1 cycle 3 cycles (Cu,Ni,Pd) 6 Sn 5 7 cycles Thin IMC Better Reliability
Brittle Fracture Surface (After 7 Reflow cycles) 19 Cu 6 Sn 5 (Cu,Ni) 6 Sn 5 OSP-SAC OSP-Sα Ni (Cu,Ni,Pd) 6 Sn 5 Ni/Au Ni-P/Pd/Au
20 Fracture Model (Reflow Cycles) Solder Cu 6 Sn 5 Crack Cu Solder Crack Propagation Cu OSP-SAC (Cu,Ni) 6 Sn 5 Solder OSP-Sα (Cu,Ni) 6 Sn 5 (Cu,Ni,Pd) 6 Sn 5 Ni Ni/Au Ni-P Ni-P/Pd/Au
Aging Time 21 DFR / % 100 80 60 40 20 0 0 100 300 500 1000 Aging Time / h (Temp : 150 ) Shear Speed : 200 mm/s E less Ni-P/Pd/Au E lytic Ni/Au OSP- Sα OSP- SAC
Aging Time 22 DFR / % 100 80 60 40 20 0 0 100 300 500 1000 Aging Time / h (Temp : 150 ) Shear Speed : 1000 mm/s E less Ni-P/Pd/Au E lytic Ni/Au OSP- Sα OSP- SAC
Aging Time 100 h IMC Growth --Aging Time SAC Cu OSP Sα Solder Solder Solder Solder Cu E lytic Ni/Au Ni 23 E less Ni-P/Pd/Au Ni-P 500 h 1000 h 10 μm 5μm SJR Excellent Poor Excellent Excellent
Aging Time Aging Time --OSP-SAC FE-SEM Sn EDX Cu 24 100 h 500 h 1000 h 10μm Cu 6 Sn 5 Cu 3 Sn
Aging Time --OSP- Sα Aging EDX FE-SEM Time Sn Cu 25 100 h 500 h (Cu,Ni) 6 Sn 5 1000 h 10μm (Cu,Ni) 3 Sn
SAC vs. vs. Sα 26 OSP - SAC OSP - Sα Cu 6 Sn 5 (Cu,Ni) 6 Sn 5 (Cu,Ni) 3 Sn Cu 3 Sn 2 μm Cu Cu FIB/SIM Analytical Results
Solder Aging Time --Ni/Au 27 Ni Thick IMC 0 h 100 h Poor Reliability (Cu,Ni) 6 Sn 5 500 h 1000 h
Aging Time --Ni-P/Pd/Au 28 Solder Ni-P Thin IMC 0 h 100 h Better Reliability SJR was excellent (Cu,Ni,Pd) 6 Sn 5 500 h 1000 h
Brittle Fracture Surface (After 1000 h Thermal Aging at at 150 ) Cu 6 Sn 5 (Cu,Ni) 3 Sn (Cu,Ni) 6 Sn 5 29 Cu 3 Sn OSP-SAC OSP-Sα Ni-P Ni Ni/Au Ni-P/Pd/Au (Cu,Ni,Pd) 6 Sn 5
30 Fracture Model (Thermal Aging) Solder Cu 3 Sn Cu Solder Cu 6 Sn 5 Crack Propagation OSP-SAC (Cu,Ni) 6 Sn 5 (Cu,Ni) 6 Sn 5 (Cu,Ni) 3 Sn Cu OSP-Sα (Cu,Ni,Pd) 6 Sn 5 Ni Ni/Au Ni-P Ni-P/Pd/Au
31 Summary (1)On the OSP surface finishing, the IMC growth and the solder joint reliability depended on the kind of Pb free solder. (2) The solder joint reliability of the electroless Ni-P/Pd/Au plating was equivalent to that of the electrolytic Ni/Au on the high speed shear test.
Appendix Electroless Ni-P Surface after Au Au or or Pd Pd Dissolution Au Ni-P Ni-P/Au Dissolution Ni-P Ni-P/Pd/Au Au Dissolution Pd Ni-P Ni-P 3 μm Corrosion at Ni-P Boundary No Corrosion 3 μm