1. TT 070828COST MP0602 meeting, Brno “MatPack” – deposition, modelling and characterisation of high melting point lead-free micro solders Peter T. Tang IPU

2. TT 070828COST MP0602 meeting, Brno MatPack Concept and Subprojects 3D-modelling of phase formation Prediction of solder properties Focused Ion Beam preparations SEM imaging and composition analysis Phase quantification by x-ray diffraction Determination of melting point Metrology Life cycle assessment and toxicology PVD of diffusion barriers Electroplating of alloys Deposition of multi-layers

3. TT 070828COST MP0602 meeting, Brno High Melting Point Solder Applications High melting point solder Low melting point solder (SnAgCu, 217 °C) High melting point = Low melting point plus 50 °C or more! Ref. 04121279 EC exemptions, final report (ERA Technology)

4. TT 070828COST MP0602 meeting, Brno Solder Deposition

5. TT 070828COST MP0602 meeting, Brno Electroplating Processes The following electroplating processes are established at IPU: SnZn (9% Zn)Commercial process, SLOTOLOY ZSN Melting point (eutectic) 198 ºC SnCu (0.7% Cu)Commercial process, Yuken Melting point (eutectic) 217 ºC SnCu (3% Cu)Semi-commercial process, Yuken Melting range 217-350 ºC AnSn (20% Sn)Commercial process, Technic AuroStan H Melting point (eutectic) 278 ºC Pure Au and Pure SnAvailable in several versions

6. TT 070828COST MP0602 meeting, Brno Well-known Pb-Sn Solders http://www.metallurgy.nist.gov/phase/solder/solder.html 183°C~315°C

7. TT 070828COST MP0602 meeting, Brno SnCu Phase Diagram

8. TT 070828COST MP0602 meeting, Brno Elements that can be deposited

9. TT 070828COST MP0602 meeting, Brno Multi-layers or Composition Modulated Alloys

10. TT 070828COST MP0602 meeting, Brno Tin-silver Alloys for Soldering Advantages:  Mildly alkaline electrolyte (pH=9) compatible with photoresist  No “whiskers” tendency due to a silver content of 3.8 At.%  No phase transformation at low temperatures (13 °C)  Melting point approximately 10 °C lower than pure tin  Relatively “safe” bath

11. TT 070828COST MP0602 meeting, Brno Phase Diagram of Tin-silver

12. TT 070828COST MP0602 meeting, Brno Electrolyte Composition Triethanolamine Tin chloride Potassium pyrophosphate Silver iodide Triethanolamine Potassium iodide SnCl 2 · 2 H 2 O K2P2O7K2P2O7 KI AgI C 6 H 15 NO 3 0.1810 0.5000 1.2000 0.0026 0.2000 M Room temperature pH = 9.3

13. TT 070828COST MP0602 meeting, Brno Surface Without TEA

14. TT 070828COST MP0602 meeting, Brno Rotating Cylinder Electrode

15. TT 070828COST MP0602 meeting, Brno Silver Concentration

16. TT 070828COST MP0602 meeting, Brno Rotational Speed

17. TT 070828COST MP0602 meeting, Brno Bath Temperature

18. TT 070828COST MP0602 meeting, Brno Influence of pH x2400 x1200 31% Ag 3.8% Ag

19. TT 070828COST MP0602 meeting, Brno Flip-chip Bonding Components Bumps are pure tin from a neutral electrolyte!

20. TT 070828COST MP0602 meeting, Brno Hot-stage Microscope 1. Vacuum system 2. Heating chamber (6x8x6 mm) 3. Imaging system

21. TT 070828COST MP0602 meeting, Brno Forming and Remelting c)d) AuSnNi

22. TT 070828COST MP0602 meeting, Brno Cross-section (LOM) 144.4 mg of Au and Sn powder – a slightly hypoeutectic composition of 83.1% Au and 16.9% Sn (wt.%)

23. TT 070828COST MP0602 meeting, Brno AuSn Phase Diagram Au 5 Sn AuSn Au 2 Sn Sample composition

24. TT 070828COST MP0602 meeting, Brno Cross-section (SEM) Au 5 S n Au80Sn20 (eut.)