Lead-Free Solder Cyclic Plasticity Characterization for Drop Test Simulations

2006 ◽  
Author(s):  
E.L. Bonnaud ◽  
P. Gudmundson
Keyword(s):  
Drop Test ◽  
Lead Free ◽  
Cyclic Plasticity ◽  
Lead Free Solder ◽  
Free Solder

Analysis Methods for Characterizing Drop Test Robustness of Lead-Free FBGAs

2005 ◽  
Author(s):  
J. Walter ◽  
R. Fischer ◽  
C. Birzer
Keyword(s):  
Crack Detection ◽  
Printed Circuit Boards ◽  
Ion Beam ◽  
Drop Test ◽  
Test Reliability ◽  
Lead Free ◽  
Detection Methods ◽  
Lead Free Solder ◽  
Analysis Methods ◽  
Free Solder

Abstract During the last few years the drop test has become more and more important for electronic handheld components. Drop test reliability for lead-free solder interconnects is an extreme challenge today. Thus, the need for improved micro structural diagnostics of new material combinations and crack detection methods has increased. The target of this paper is to summarize detection and analysis methods for solder joint cracks, material characterization [1] and preparation methods of assembled printed circuit boards (PCB) after a drop test to completely understand lead-free solder interconnect reliability in fine pitch ball grid array packages (FBGA). In particular, we will introduce the outstanding advantages of embedded cross-sections combined with ion beam polishing (IBP), dye- or rather resin-penetration, selective tin etch and micro-hardness measurements.

Effect of Solder Composition and Substrate Surface Finish on Board Level Drop Test Reliability

2005 ◽  
Author(s):  
Don-Son Jiang ◽  
Joe Hung ◽  
Yu-Po Wang ◽  
C. S. Hsiao
Keyword(s):  
Solder Joint ◽  
Substrate Surface ◽  
Drop Impact ◽  
Drop Test ◽  
Test Reliability ◽  
Lead Free ◽  
Lead Free Solder ◽  
Snagcu Solder ◽  
Free Solder ◽  
Board Level

For handheld or portable telecommunication devices such as mobile phone, PDA, etc., board level joint reliability during drop impact is a great concern to simulate mishandling during usage. In general, solder composition and substrate surface finish would principally determine the solder joint reliability. Board level drop test reliability of two solder compositions (SnPb and lead free SnAgCu) and surface finishes (Ni/Au and OSP) were examined in this study. The result indicated SnAgCu lead free solder showed poorer reliability life than Sn-Pb solder during drop impact. The crack path in SnPb solder joint almost went through bulk solder near substrate side. However, another IMC/Ni interfacial failure mode near substrate side was found in SnAgCu solder to cause lower reliability. This difference could attribute to higher strength of SnAgCu solder and deformation with higher strain rate in drop test. Comparison between two surface finishes indicated Ni/Au is better than OSP in both SnPb and SnAgCu lead free solder joints. In SnAgCu lead free solder joint with OSP, there are thicker Cu6Sn5 IMC and many large Ag3Sn IMC plates in interface to degrade the interfacial bonding, so drop impact would easily cause the all cracks through IMC/Cu interface and then reduce the reliability.

scholarly journals Issues on Viscoplastic Characterization of Lead-Free Solder for Drop Test Simulations

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Etienne L. Bonnaud
Keyword(s):  
Material Behavior ◽  
Drop Test ◽  
Lead Free ◽  
Strain Rates ◽  
Electronic Packages ◽  
Lead Free Solder ◽  
Mixed Hardening ◽  
Drop Tests ◽  
Free Solder

Reliable drop test simulations of electronic packages require reliable material characterization of solder joints. Mechanical properties of lead-free solder were here experimentally investigated for both monotonic and cyclic loading at different strain rates. With regards to the observed complex material behavior, the nonlinear mixed hardening Armstrong and Frederick model combined with the Perzyna viscoplastic law was chosen to fit the experimental data. This model was subsequently implemented into a commercial finite element code and used to simulate drop tests. Actual drop test experiments were conducted in parallel and experimental results were compared to simulations. Prediction discrepancies were analyzed and explanations suggested.

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