for High Reliable Gold Wire Bonding with Electronic Devices for Space Applications

Transcription

1 JAXA 23 rd Microelectronics Workshop Electroless ess Ni/Pd/ Plating for High Reliable Gold Wire Bonding with Electronic Devices for Space Applications (1) Plating Combinations and Reliability (2) Grain Size and Crystal Growth (3) Diffusion of Underplated Metal onto surface (4) Wire Bonding Reliability Ranking of Plating Yukihisa Hiroyama Hitachi Chemical Co., Ltd.

2 1 Structure of BGA Assembly Gold Wire Semiconductor Chip Die Bonding Material Wire Bonding Solder Joint Package Substrate t Printed Circuit Board Molding Material Solder Ball

3 2 Wire Bonding Copper Line Aluminum Electrode LSI Gold Wire Resist Die Bonding Material Package Substrate Gold Plated Terminal

4 3 Solder Ball Joint Copper Pad Package Substrate Resist Solder Ball Solder Ball Gold Plated Terminal

5 4 Characterization of Gold Plating Item E lytic Ni/ (5/0.5µm) 5µm) E less Ni/ (ENIGEG) (5/0.5µm) 5µm) E less Ni/Pd/ (ENEPIGEG) (5/0.5/0.5µm) 5µm) Wire Bondability OK OK OK Wire Bondability after Aging* Wire Bondability after Aging* and Plasma** OK NG OK OK OK OK Solder Joint Reliability OK NG OK * Aging : 150ºC, 50 hours ** Plasma : O 2 plasma

6 5 Gold Plating Combination i with E less and E lytic Processes Gold Plating Process ENEPIGEG (Ni/Pd/) ENEPIG (Ni/Pd/IG) ENIGEG (Ni/) Ni(SBWatt)/E lytic Ni(BWatt)/E lytic Ni(BSulf)/E lytic Ni(SBWatt)/IGEG EN/E lytic Cu/E lytic Thickness (µm) 5/0.5/0.5 5/0.5/0.05 5/0.5 5/0.5 5/0.5 5/0.5 5/0.55 5/

7 6 Wire Bonding Reliability of Gold Plating Combinations As Gold Plating HeatTreatment 8 (150 o C, 3h) Pulll Strength (gf) 0 ENEPIGEG (Ni/Pd/) ENEPIG (Ni/ Pd/IG) ENIGEG (N Ni/) Ni(SBWatt) /E lytic Ni(BWatt) /E lytic Ni(BSulf.) /E lytic Ni(SBWatt) /IGEGG EN/E'lytic Cu/E'lytic

8 7 Surface Morphology and FIB/SIM Cross Section ENEPIGEG (Ni/Pd/) ENEPIG (Ni/Pd/IG) ENIGEG (Ni/) FIB/SIM Cro oss Sect tion Sur rface Morph hology Pd Ni 1 µm Pd Ni 1 µm Ni 1 µm

9 8 Surface Morphology and FIB/SIM Cross Section Ni(SBWatt)/ Ni(BWatt)/ Ni(BSulf.)/ Sur rface Morph hology FIB/SIM Cro oss Sect tion Ni 1 µm Ni 1 µm Ni 1 µ m

10 9 Surface Morphology and FIB/SIM Cross Section Ni(SBWatt)/IGEG EN/E lytic Cu/E lytic Sur rface Morph hology FIB/SIM Cro oss Sect tion Ni 1 µm Ni 1 µm Cu 1 µm

11 10 EBSP Mapping of Gold ENEPIGEG (Ni/Pd/) ENIGEG (Ni/) Ni(SBWatt)/E lytic Ni(BWatt)/E lytic 0.18 m m mm m m2 Ni(BSulf.)/E lytic Ni(SBWatt)/IGEG EN/E lytic Cu/E lytic m m m 0.03 m m : Average crosssectional area of gold grain EBSP: Electron Back Scattering Pattern

12 11 EBSP Mapping Ni(SBWatt)/IGEG Ni Ni Ni Cu Cu Cu 1 m All Ni Cu EDX E lytic Ni(SBWatt)/IGEG Energy Dispersion EBSP: Electron Back Scattering Profile Xray Spectrometry

13 12 EBSP Mapping ENEPIGEG (Ni/Pd/) Electroless Ni/Electroless Pd/ Immersion /Electroless Pd Pd Pd 0.5 m All Pd EDX ENEPIGEG EBSP: Electron Back Scattering Profile Energy Dispersion Xray Spectrometry

14 13 EBSP Mapping Cu/E lytic Copper/Electrolytic Cu Cu All Cu Cu/E lytic EBSP: Electron Back Scattering Profile Cu 0.5 m EDX Energy Dispersion Xray Spectrometry

15 14 Thermal Diffusion Behavior of Underplated Metal By XPS Analysis (Xray Photoelectron Spectrometry) Gold Plating 3 hours 25 hours 50 hours Process Ni Cu Pd Ni Cu Pd Ni Cu Pd ENEPIGEG (Ni/Pd/) ENEPIG (Ni/Pd/IG) ENIGEG (Ni/) Ni(SBWatt)/ Ni(BWatt)/ Ni(BSulf)/ Ni(SBWatt)/IGEG EN/E lytic Cu/E lytic Atomic% Heat Treatment: 150ºC

16 15 Nickel Distribution over Gold Plating Surface By AES Analysis (ger Electron Spectrometry) ENIGEG (Electroless Ni/) : 5µm/0.5µm Heat Treatment: 150ºC, 50h Ni A u

17 16 Grain Boundary Diffusion i and Bulk Diffusion (Interdiffusion) Contamination on Gold Surface Grain Boundary Bulk Diffusion (Interdiffusion) Gold Under Plated Metal Gold Grain Grain Boundary Diffusion Under Plated Metal Grain

18 17 Model of Grain Structure and Diffusion on ENEPIGEG ENEPIGEG (Electroless Ni/Pd/) IGEG IGEG EP EP EN FIB/SIM Analytical Result EN Grain Boundary Diffusion

19 18 Model of Grain Structure and Diffusion on Ni(SBWatt)/ E lytic NiO E lytic or IGEG Ni(SBWatt) IGEG (E less ) Ni(SBWatt) Ni(SBWatt) FIB/SIM Analytical Result Grain Boundary Diffusion

20 19 Model of Grain Structure and Diffusion on BNi/ and EN/ E less Ni/ IGEG EN NiO IGEG or E lytic E lytic EN E lytic Ni(BWatt) FIB/SIM Analytical Result Bright Ni and EN E lytic Bright Ni Plating (1) Bright Watt (2) Bright Sulfamate Grain Boundary Diffusion

21 20 Model of Grain Structure and Diffusion on ENEPIG ENEPIG (Electroless Ni/Pd/IG) Pd Organic Contamination IG IG EP EP EN FIB/SIM Analytical Result EN Grain Boundary Diffusion

22 21 Model of Grain Structure and Diffusion on Cu/E lytic CuO (Grain boundary) CuO (Bulk) E lytic E lytic Cu FIB/SIM Analytical Result Cu Interdiffusion (Bulk Diffusion) Grain Boundary Diffusion

23 22 Estimated Ranking of Wire Bonding Reliability Good ENEPIGEG, Ni(SBWatt)/IGEG and Ni(SBWatt)/E lytic Wire Bondin ng Relia ability ENEPIG, Ni(BWatt)/E lytic And Ni(BSulf.)/E lytic lytic ENIGEG, EN/E lytic Poor Cu/E lytic

24 23 Summary (1) The reliability of ENEPIGEG (E less Ni/Pd/) and E lytic Ni (SBWatt)/IGEG was equivalent to thatt of E lytic Ni (SB Watt)/E lytic after the heat treatment. (2) The reliability dependedd d on the diffusioni behavior of the underplated metals and the grain size of the gold deposit. (3) The grain size of plating coordinated with the grain size of the underplated d metals as the epitaxial crystal growth.