Future Electronic Devices Technology in Cosmic Space

and Lead-free Solder Joint Reliability

Future Electronic Devices Technology Future Electronic Devices Technology in Cosmic Space in Cosmic Space

and Leadand Lead--free Solder Joint Reliabilityfree Solder Joint Reliability

Yoshinori EjiriHitachi Chemical Co., Ltd.

The 22nd Microelectronics Work

Key Points(1) High Speed Solder Ball Shear Test(2) Relationship between Surface Finishing

and Solder Ball Joint Reliability

Aero Space

Mobile Phone

Digital CameraApplication of Semiconductor PackagesApplication of Semiconductor Packages

Car

Mobile PC

Digital Video Camera

PCB

Airplane

SCP

1

TSOP (Thin Small Outline Package)

CSP(Chip Scale Package)

2

Metal LeadMetal Lead(Fe/Ni Alloy)(Fe/Ni Alloy)

Assembly Area Below 1/2 Assembly Area Below 1/2 Assembly Area Below 1/2

Solder BallSolder Ball

Increasing DensityDecreasing Size

Increasing DensityDecreasing Size

3

MoldingMaterial

Gold Wire Die BondingMaterial

SemiconductorChip

SolderBall

Printed Circuit Board

Package Substrate

Shock / Vibration

Stress Concentration

Shock / VibrationShock / Vibration

Stress ConcentrationStress Concentration

Structure of BGA AssemblyStructure of BGA Assembly

Solder Ball

Package SubstrateCopper Pad

Solder BallSolder Mask

4

ElectrolessNi-P/Pd/AuElectrolessElectrolessNiNi--P/Pd/AuP/Pd/Au

Solder Ball JointSolder Ball Joint

●●Organic Solder Preservative (OSP)Organic Solder Preservative (OSP)Immersion AgImmersion AgImmersion Immersion SnSnElectrolytic AuElectrolytic Au

●●Electrolytic Ni / Electrolytic AuElectrolytic Ni / Electrolytic Au●●Electroless Ni / Immersion Au / Electroless AuElectroless Ni / Immersion Au / Electroless Au

(ENIGEG)(ENIGEG)●●Electroless Ni / Electroless Pd / Immersion AuElectroless Ni / Electroless Pd / Immersion Au

/ Electroless Au (ENEPIGEG)/ Electroless Au (ENEPIGEG)

5

Surface Finishing for Copper PadSurface Finishing for Copper Pad

HighHigh--speed Solder Ball Shear Testspeed Solder Ball Shear Test

Solder BallSolder Ball

ShearTool

Shear SpeedShear Speed0.5, 20, 200, 1000 mm・s-1 High Speed

10mm/s or more(JEDEC JESD22-B117A)

High SpeedHigh Speed10mm/s or more10mm/s or more

(JEDEC JESD22(JEDEC JESD22--B117A)B117A)Low

Copper Pad

Ductile

High

Package Substrate

Brittle

Solder Mask

6

High-speed Solder Ball Shear TestHigh-speed Solder Ball Shear Test

0 200 400 600 80005

101520253035

Ductile

InterfacialStrength

SolderStrength

Displacement (μm)

Shea

r For

ce (N

)

7Ductile – Low SpeedDuctile – Low SpeedShear Strength

Solder＜Interface

0 200 400 600 80005

101520253035

Displacement (μm)

Shea

r For

ce (N

)

8Brittle – High SpeedBrittle – High Speed

Brittle

Shear StrengthInterface ＜Solder

InterfacialStrength

SolderStrength

DAGE 4000HS Bond Tester (Dage Precision Industries, Ltd.)

DAGE 4000HS Bond Tester DAGE 4000HS Bond Tester ((DageDage Precision Industries, Ltd.)Precision Industries, Ltd.)

9

High-speed Solder Ball Shear TestHigh-speed Solder Ball Shear Test

Duc

tile

Frac

ture

Rat

e (D

FR) /

％

0.5

DuctileBrittle

Ni-P : 5 μmPd : 0.1 μmAu : 0.3 μm

20 2000

20

40

60

80

100

0.5 20 200Shear Speed/ mm・s-1

1000 1000

10

High-speed Solder Ball Shear TestHigh-speed Solder Ball Shear TestLow Speed

NiNi--P/AuP/Au NiNi--P/P/PdPd/Au/Au

Influence of Surface Finishing on Solder Joint Reliability

Relationship between Surface Finishing and Solder Ball Joint Reliability

Surface Finishing Solder Ball

OSP

E’less Ni-P/Pd/Au

E’lytic Ni/Au

OSP123

4

Reflow Cycles (Max Temp : 252℃) : 1, 3, 7Aging Time（Temp : 150℃） : 100, 300, 500, 1000 h

Evaluation Condition

Combination of Surface Finishing and Solder Ball

SAC305※

SnNiX （Sα）

※ : Sn3.0Ag0.5Cu,

SAC305※

SAC305※

11

Experimental ConditionExperimental Condition

1 3 70

20

40

60

80

100

OSP-SACOSP-Sα

E’lytic Ni/AuE’less Ni-P/Pd/Au

DFR

/ ％

12

Reflow CyclesReflow Cycles

Shear Speed : 200 mm/sShear Speed : 200 mm/s

Reflow Cycles(Max Temp : 252℃)

1 3 70

20

40

60

80

100

DFR

/ ％

OSP-SACOSP-Sα

E’lytic Ni/AuE’less Ni-P/Pd/Au

13

Shear Speed : 1000 mm/sShear Speed : 1000 mm/s

Reflow Cycles(Max Temp : 252℃)

Reflow CyclesReflow Cycles

ExcellentPoorSJR Excellent Excellent5μm

OSPSAC Sα

E’lessNi-P/Pd/Au

E’lyticNi/Au

1

3

7

ReflowCycles

5μm10 μm

Cu

Solder

Ni-PCu

Solder Solder Solder

Ni

14

IMC Growth - Reflow CyclesIMC Growth - Reflow Cycles

Crack of IMC

Poor Reliability

Crack of IMCCrack of IMC

Poor ReliabilityPoor Reliability

1 cycle 3 cycles

7 cycles

Cu

Solder

Crack

15

Reflow Cycles - OSP-SACReflow Cycles - OSP-SAC

Cu6Sn5

Ni : Thin IMC Layer

Better Reliability

Ni : Thin IMC LayerNi : Thin IMC Layer

Better ReliabilityBetter Reliability

Cu

Solder

1 cycle 3 cycles

7 cycles

16

（Cu,Ni）6Sn5

Reflow Cycles - OSP-SαReflow Cycles - OSP-Sα

Thick IMC Poor ReliabilityThick IMC Poor Reliability

Ni

Solder

（Cu,Ni）6Sn5

1 cycle 3 cycles

7 cycles

17

Reflow Cycles - Ni/AuReflow Cycles - Ni/Au

Ni-P

Solder

（Cu,Ni,Pd）6Sn5

1 cycle 3 cycles

7 cycles

18

Thin IMC Better ReliabilityThin IMC Better Reliability

Reflow Cycles - Ni-P/Pd/AuReflow Cycles - Ni-P/Pd/Au

OSP-SAC

Ni-P/Pd/AuNi/Au

OSP-Sα

19

（Cu,Ni,Pd）6Sn5

Cu6Sn5 （Cu,Ni）6Sn5

Ni

Brittle Fracture Surface（After 7 Reflow cycles）

Brittle Fracture Surface（After 7 Reflow cycles）

Crack

Cu

Cu6Sn5

OSP-SAC

Ni-P/Pd/AuNi/Au

OSP-Sα

Cu

Solder

Ni Ni-P

（Cu,Ni,Pd）6Sn5

（Cu,Ni）6Sn5

（Cu,Ni）6Sn5 Solder

Solder

20

Fracture Model (Reflow Cycles)Fracture Model (Reflow Cycles)

Crack Propagation

Aging Time / h

E’less Ni-P/Pd/AuE’lytic Ni/Au

OSP- SαOSP- SAC

0 100 300 500 1000

020

4060

80

100

DFR

/ ％

21

Aging TimeAging Time

(Temp : 150℃)

Shear Speed : 200 mm/sShear Speed : 200 mm/s

0 100 300 500 1000

020

4060

80

100

DFR

/ ％

E’less Ni-P/Pd/AuE’lytic Ni/Au

OSP- SαOSP- SAC

22

Shear Speed : 1000 mm/sShear Speed : 1000 mm/s

Aging Time / h(Temp : 150℃)

Aging TimeAging Time

Excellent Poor

100 h

500 h

1000 h

Ni-PCuCu

Solder Solder Solder Solder

5μm10 μm

OSPSAC Sα

SJR

AgingTime

E’lessNi-P/Pd/Au

E’lyticNi/Au

Ni

Excellent Excellent

23

IMC Growth - Aging TimeIMC Growth - Aging Time

100 h

500 h

1000 h

FE-SEM Sn Cu

10μm

AgingTime

EDX

24

Cu6Sn5

Cu3Sn

Aging Time - OSP-SACAging Time - OSP-SAC

10μm

FE-SEM

100 h

500 h

1000 h

AgingTime Sn Cu

EDX

25

（Cu,Ni）6Sn5

（Cu,Ni）3Sn

Aging Time - OSP- SαAging Time - OSP- Sα

Cu Cu

2 μm

FIB/SIM Analytical Results

26

SAC vs. SαSAC vs. Sα

Cu6Sn5（Cu,Ni）6Sn5

（Cu,Ni）3Sn

Cu3Sn

OSP - SAC OSP - Sα

0 h 100 h

500 h 1000 h

Ni

Solder

（Cu,Ni）6Sn5

27

Thick IMC

Poor Reliability

Thick IMCThick IMC

Poor ReliabilityPoor Reliability

Aging Time - Ni/AuAging Time - Ni/Au

Ni-P

0 h 100 h

500 h 1000 h

Solder

（Cu,Ni,Pd）6Sn5

SJR was excellent

28

Thin IMC

Better Reliability

Thin IMCThin IMC

Better ReliabilityBetter Reliability

Aging Time - Ni-P/Pd/AuAging Time - Ni-P/Pd/Au

Ni-P/Pd/AuNi/Au

OSP-SAC OSP-Sα

29

Cu6Sn5

Brittle Fracture Surface（After 1000 h Thermal Aging at 150℃）

Brittle Fracture Surface（After 1000 h Thermal Aging at 150℃）

（Cu,Ni）6Sn5

（Cu,Ni）3Sn

（Cu,Ni,Pd）6Sn5

Ni

Ni-P

Cu3Sn

CuOSP-SAC

Ni/Au

OSP-SαCu

Ni

Cu6Sn5

Cu3Sn

（Cu,Ni）6Sn5

（Cu,Ni）6Sn5

Ni-P/Pd/AuNi-P

（Cu,Ni,Pd）6Sn5

Solder

Crack Propagation

Solder

（Cu,Ni）3Sn

30

Fracture Model (Thermal Aging)Fracture Model (Thermal Aging)

（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.

31

SummarySummary

Ni-P/Au

Ni-PAu

Dissolution

Ni-P/Pd/Au

Ni-P Ni-P

AuPd

Ni-P

Corrosion at Ni-P Boundary3 μm3 μm

Dissolution

No Corrosion

Appendix

Electroless Ni-P Surfaceafter Au or Pd DissolutionElectroless Ni-P Surface

after Au or Pd Dissolution