Simulation of mechanical response of solder joints under drop impact using equivalent layer models

2005 ◽  
Author(s):  
Jie Gu ◽  
C.T. Lim ◽  
A.A.O. Tay
Keyword(s):  
Mechanical Response ◽  
Solder Joints ◽  
Drop Impact ◽  
Equivalent Layer

Understanding and Testing for Drop Impact Failure

2005 ◽  
Author(s):  
S. K. W. Seah ◽  
E. H. Wong ◽  
R. Ranjan ◽  
C. T. Lim ◽  
Y.-W. Mai
Keyword(s):  
Printed Circuit Board ◽  
Mechanical Response ◽  
Solder Joints ◽  
Drop Impact ◽  
Consumer Products ◽  
Circuit Board ◽  
Bga Packages ◽  
Response Board ◽  
Drop Tests ◽  
Board Level

This paper presents the results of experiments aimed at studying the effects of drop impact on portable electronics and reproducing these effects in controllable tests. Firstly, a series of drop tests were performed on consumer products (mobile phones and PDAs) to understand how the printed circuit board (PCB) within a product behaves in actual drop conditions. These product-level drop tests show that in drop impact, there are three possible types of mechanical response which can stress the 2nd level interconnections of CSP and BGA packages, namely: 1) flexing of the PCB on its supports, dominated by the 1st (fundamental) natural frequency; 2) flexing of the PCB resulting from direct impact or knocking against the PCB, typically dominated by higher natural frequencies; and 3) inertia loading on the solder joints due to high accelerations. Next, a series of board-level experiments were designed to separately study each of the three types of mechanical response. Board flexing due to direct impacts is the most severe response due to the strong strain amplitudes generated. Given the same input shock, the conventional board-level test — where the PCB flexes on its supports — produces much lower strain amplitudes. Inertia loading on the solder joints is practically negligible. Since PCB flexing is the main failure driver, a simple vibration test, which reproduces the strains observed in drop impact, is suggested as an alternative to time-consuming drop impact tests.

Damage Evolution in Lead Free Solder Joints in Isothermal Fatigue

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Awni Qasaimeh ◽  
Sa’d Hamasha ◽  
Younis Jaradat ◽  
Peter Borgesen
Keyword(s):  
Crack Initiation ◽  
Mechanical Response ◽  
Solder Joints ◽  
Fatigue Testing ◽  
Hysteresis Loops ◽  
Damage Function ◽  
Lead Free ◽  
Lead Free Solder ◽  
Sac305 Solder ◽  
Free Solder

The extrapolation and generalization of accelerated test results for lead free solder joints require the identification of a damage function that can be counted on to apply beyond the region of the test. Individual ball grid array (BGA) scale Sn3Ag0.5Cu (SAC305) solder joints were subjected to isothermal shear fatigue testing at room temperature and 65 °C. The resulting mechanical response degradation and crack behavior, including strain hardening, crack initiation, and propagation, were correlated with the inelastic work and effective stiffness derived from load–displacement hysteresis loops. Crack initiation was found to scale with the accumulated work, independently of cycling amplitude and strain rate. The subsequent damage rate varied slightly with amplitude.

Examination of the impact test equipment used for the assessment of drop impact reliability for the solder joints

2002 ◽  
Vol 2002 (0) ◽  
pp. 239-240
Author(s):  
Qiang YU ◽  
Hironobu KIKUCHI ◽  
Keiji WATANABE ◽  
Manabu KAKINO ◽  
Noriyuki FUJIWARA ◽  
...  
Keyword(s):  
Impact Test ◽  
Solder Joints ◽  
Drop Impact ◽  
Test Equipment ◽  
Impact Reliability ◽  
The Impact

Cracking of the Intermetallic Compound Layer in Solder Joints Under Drop Impact Loading

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Tong An ◽  
Fei Qin
Keyword(s):  
Intermetallic Compound ◽  
Solder Joint ◽  
Impact Loading ◽  
Driving Force ◽  
Solder Joints ◽  
Compound Layer ◽  
Drop Impact ◽  
Lead Free ◽  
Intermetallic Compound Layer ◽  
Crack Driving Force

The significant difference between failure modes of lead-containing and lead-free solder joints under drop impact loading remains to be not well understood. In this paper, we propose a feasible finite element approach to model the cracking behavior of solder joints under drop impact loading. In the approach, the intermetallic compound layer/solder bulk interface is modeled by the cohesive zone model, and the crack driving force in the intermetallic compound layer is evaluated by computing the energy release rate. The numerical simulation of a board level package under drop impact loading shows that, for the lead-containing Sn37Pb solder joint, the damage in the vicinity of the intermetallic compound layer initiates earlier and is much greater than that in the lead-free Sn3.5Ag solder joint. This damage relieves the stress in the intermetallic compound layer and reduces the crack driving force in it and consequently alleviates the risk of the intermetallic compound layer fracturing.

Strain Rate Effects and Rate-Dependent Constitutive Models of Lead-Based and Lead-Free Solders

2009 ◽  
Vol 77 (1) ◽  
Author(s):  
Fei Qin ◽  
Tong An ◽  
Na Chen
Keyword(s):  
Strain Rate ◽  
Impact Analysis ◽  
Solder Joints ◽  
High Strain ◽  
Drop Impact ◽  
Lead Free ◽  
Strain Rates ◽  
High Strain Rates ◽  
Rate Dependent ◽  
Lead Free Solders

As traditional lead-based solders are banned and replaced by lead-free solders, the drop impact reliability is becoming increasingly crucial because there is little understanding of mechanical behaviors of these lead-free solders at high strain rates. In this paper, mechanical properties of one lead-based solder, Sn37Pb, and two lead-free solders, Sn3.5Ag and Sn3.0Ag0.5Cu, were investigated at strain rates that ranged from 600 s−1 to 2200 s−1 by the split Hopkinson pressure and tensile bar technique. At high strain rates, tensile strengths of lead-free solders are about 1.5 times greater than that of the Sn37Pb solder, and also their ductility are significantly greater than that of the Sn37Pb. Based on the experimental data, strain rate dependent Johnson–Cook models for the three solders were derived and employed to predict behaviors of solder joints in a board level electronic package subjected to standard drop impact load. Results indicate that for the drop impact analysis of lead-free solder joints, the strain rate effect must be considered and rate-dependent material models of lead-free solders are indispensable.

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