Surface properties and Surface properties and wetting characteristics wetting characteristics of of lead-free solder alloys lead-free solder alloys E. Ricci, D. Giuranno, F. Gnecco, S. Amore, T. Lanata, R. Novakovic National Research Council (CNR) – Institute for Energetics and Interphases (IENI) Genoa - Italy
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Surface properties and wetting characteristics of lead-free solder alloys E. Ricci, D. Giuranno, F. Gnecco, S. Amore, T. Lanata, R. Novakovic National.
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Surface properties and Surface properties and wetting characteristics of wetting characteristics of
lead-free solder alloyslead-free solder alloys
E. Ricci, D. Giuranno, F. Gnecco, S. Amore, T. Lanata, R. Novakovic
National Research Council (CNR) – Institute for Energetics and Interphases (IENI)Genoa - Italy
Contribution from IENI Genova to COST 531Contribution from IENI Genova to COST 531
Characterization Surface Properties and wetting behaviour of Selected groups of Lead-free Alloys as
Soldering Materials
Surface Tension + modelling: Binary systems Ag-Cu Au-Sn
Cu-Sn Au-InIn-Sn Bi-In
Wetting behaviour:Ternary systems: Au-In-Sn/Cu
Bi-In-Sn/CuBinary sub-systems: Au-In/Cu
Bi-In /CuAu-Sn/(Cu,Ni)In-Sn /(Cu,Ni)Cu-Sn/(Cu,Ni)
Final Meeting COST Action 531 Vienna 17-18 May 2007
Preparation of the samplesPreparation of the samples
Preparation of the alloys from the pure elements by melting in a clean atmosphere
Control of alloys compositions by SEM-EDS
Mass of alloy sample mechanical and chemical cleaned
Final Meeting COST Action 531 Vienna 17-18 May 2007
ExperimentalExperimental
Surface TensionSurface Tension
Contact AnglesContact Angles
Acquisition of drop profile in real time (2 s) by ASTRAview®
appropriate Software
Oxygen Partial Pressure
Temperature
Final Meeting COST Action 531 Vienna 17-18 May 2007
SV = LS + LV cos
< 90°wettability
> 90° no wettability
S
V
LV
LS
Liquid
Final Meeting COST Action 531 Vienna 17-18 May 2007
Surface Tension ResultsSurface Tension Results
Temperature [K]
1273 1323 1373 1423 1473 1523
Sur
face
Ten
sion
[mN
/m]
400
500
600
700
800
900
1000
1100
1200
pure Au
6.1 at %Sn
11.8 at% Sn
37.8 at% Sn
54.1 at% Sn
81.8 at% Sn
95.3 at% Sn
pure Sn
Temperature [K]
1273 1323 1373 1423 1473 1523
Sur
face
tens
ion
[mN
/m]
400
500
600
700
800
900
1000
1100
1200
pure Au
9.9 In at%
30.0 In at%
36.4 In at%
49.5 In at%54.9 In at%
88.7 In at%
pure In *
Experimental determination of the surface tension
Theoretical calculations of the surface tension
Experimental data are in good agreement with surface tension values calculated using different theoretical modelsExperimental data are in good agreement with surface tension values calculated using different theoretical models
Surface tensionSurface tension
Final Meeting COST Action 531 Vienna 17-18 May 2007
at%
Au
at%
Au
at%
Au
at%
Au
Au-InAu-InAu-InAu-In Au-SnAu-SnAu-SnAu-Sn
Experimental determination of the surface tension
Theoretical calculations of the surface tension
Experimental data are in good agreement with surface tension values calculated using different theoretical modelsExperimental data are in good agreement with surface tension values calculated using different theoretical models
Surface tensionSurface tension
Final Meeting COST Action 531 Vienna 17-18 May 2007
Final Meeting COST Action 531 Vienna 17-18 May 2007
ConclusionsConclusions
Complete characterization of the surface properties and the wetting behaviour of
selected groups of lead-free solder alloys
In-Sn and Cu-Sn are good candidates as basic systems for new lead free solders concerning their wettability on Cu and Ni
The additional elements should be chosen in order to preserve the wetting properties to exchange the and phase formation at the interface, and inhibit the excessive growth of a reactive layer keeping good mechanical and electrical properties
Final Meeting COST Action 531 Vienna 17-18 May 2007