A theoretical model for predicting LED product lifetime based on solder joint failure

2019 ◽  
Author(s):  
Dinusha R. Thotagamuwa ◽  
Nadarajah Narendran ◽  
Yi-Wei Liu ◽  
Xi Mou
Keyword(s):  
Theoretical Model ◽  
Solder Joint ◽  
Joint Failure ◽  
Product Lifetime

Experimental Investigation by Speckle Interferometry of Solder Joint Failure Under Thermomechanical Load Aggravated by Boundary Conditions at Board Level

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
D. N. Borza ◽  
I. T. Nistea
Keyword(s):  
Solder Joint ◽  
Fundamental Frequency ◽  
Printed Circuit Board ◽  
Speckle Interferometry ◽  
Circuit Board ◽  
Joint Failure ◽  
Printed Circuit ◽  
Out Of Plane ◽  
Fringe Patterns ◽  
Board Level

Reliability of electronic assemblies at board level and solder joint integrity depend upon the stress applied to the assembly. The stress is often of thermomechanical or of vibrational nature. In both cases, the behavior of the assembly is strongly influenced by the mechanical boundary conditions created by the printed circuit board (PCB) to casing fasteners. In many previously published papers, the conditions imposed to the fasteners are mostly aiming at an increase of the fundamental frequency and a decrease of static or dynamic displacement values characterizing the deformation. These conditions aim at reducing the fatigue in different parts of these assemblies. In the photomechanics laboratory of INSA Rouen, the origins of solder joint failure have been investigated by means of full-field measurements of the flexure deformation induced by vibrations or by forced thermal convection. The measurements were done both at a global level for the whole printed circuit board assembly (PCBA) and at a local level at the solder joints where failure was reported. The experimental technique used was phase-stepped laser speckle interferometry. This technique has a submicrometer sensitivity with respect to out-of-plane deformations induced by bending and its use is completely nonintrusive. Some of the results were comforted by comparison with a numerical finite elements model. The experimental results are presented either as time-average holographic fringe patterns, as in the case of vibrations, or as wrapped phase patterns, as in the case of deformation under thermomechanical stress. Both types of fringe patterns may be processed so as to obtain the explicit out-of-plane static deformation (or vibration amplitude) maps. Experimental results show that the direct cause of solder joint failure may be a high local PCB curvature produced by a supplementary fastening screw intended to reduce displacements and increase fundamental frequency. The curvature is directly responsible for tensile stress appearing in the leads of a large quad flat pack (QFP) component and for shear in the corresponding solder joints. The general principle of increasing the fundamental frequency and decreasing the static or dynamic displacement values has to be checked against the consequences on the PCB curvature near large electronic devices having high stiffness.

Investigation on the failure criterion of reliability testing for Pb-free BGA packages

2010 ◽  
Vol 2010 (1) ◽  
pp. 000105-000109
Author(s):  
Weidong Xie ◽  
Tae-Kyu Lee ◽  
Kuo-Chuan Liu ◽  
Jie Xue
Keyword(s):  
Solder Joint ◽  
Failure Criterion ◽  
Reliability Testing ◽  
Threshold Values ◽  
Joint Failure ◽  
Failure Distribution ◽  
Free Solder ◽  
The Impact ◽  
Different Sources ◽  
Over Time

Daisy-chained test vehicles are commonly used in board level reliability testing. By continuously monitoring the in-situ daisy chain resistance change over time, a failure could be captured during cycling and eventually the failure data could be used to establish the solder joints failure distribution under different testing conditions. One of the most debatable matters is that when should one to determine a failure to occur. Per IPC 9701A [1] a failure is defined as 10 1000-ohm events in 1 micro-second duration for event detector or 20% increase over the baseline resistance for data logger. Other threshold values such as 100, 300, or 500 ohms are also commonly used by packaging reliability community. Such a wide range of failure threshold values may introduce significant delta in terms of cycle numbers for Pb-free solder joints if different criteria would be used as reported by Henshall, etc [2]. Therefore a systematic study of the impact of using such diversified resistance values on the final failure distribution is necessary and important such that no big difference among reliability results from different sources. The purpose of this study is to investigate the impact of different failure thresholds on Pb-free solder joint failure distribution for most commonly used packages. The test vehicle, designed on an 8″×15″ double-sided printed circuit board (PCB) with multiple test sites, was populated on both sides with daisy-chained components. To reflect the real situation, the components were selected to include different package types (FCBGA, PBGA, CSP, QFN, etc), different pitches (0.4–1.0 mm), and different package size (6–50mm). The assembled test vehicles then went through 0C–100C thermal cycling, the cycle numbers corresponding to different resistance thresholds were recorded and compared. The test results showed that the failure threshold has significant impact on Pb-free solder joint failure distribution, thus it is important to unify the failure criterion such that the reliability results from different sources could be compared side by side. For some packages especially small wire-bond packages that have relatively low baseline resistance, the 20% failure criterion may be too sensitive to the resistivity changes caused not by solder joint failure but other events such as connection cable resistivity change over time or temperature.

Solder joint failure modes in crystalline Si PV modules operated in Tsukuba, Japan for 10 years

2014 ◽  
Author(s):  
Uichi Itoh ◽  
Tetsuro Nishimura ◽  
Takuro Fukami ◽  
Kenji Takamura ◽  
Akira Kita ◽  
...  
Keyword(s):  
Solder Joint ◽  
Failure Modes ◽  
Joint Failure ◽  
Pv Modules

scholarly journals Solder Joint Failure Modes in the Conventional Crystalline Si Module

2014 ◽  
Vol 55 ◽  
pp. 464-468 ◽  
Author(s):  
Uichi Itoh ◽  
Manabu Yoshida ◽  
Hideo Tokuhisa ◽  
Kohichi Takeuchi ◽  
Yasuyuki Takemura
Keyword(s):  
Solder Joint ◽  
Failure Modes ◽  
Joint Failure

Scanning Acoustic Microscopy for Solder Joint Failure Analysis and Design Improvements

2008 ◽  
Author(s):  
Ramesh Varma ◽  
Jeffrey Bartolovitch ◽  
Victor Brzozowski ◽  
Carl Sokolowski
Keyword(s):  
Solder Joint ◽  
Failure Analysis ◽  
Thermal Cycling ◽  
Electrical Power ◽  
Acoustic Microscopy ◽  
Scanning Acoustic Microscopy ◽  
Joint Failure ◽  
Analysis And Design ◽  
Cte Mismatch ◽  
Bond Pads

Abstract This paper reports using Scanning Acoustic Microscopy for solder joint failure analysis and process and design improvements. There are reliability concerns associated with solder voids or non-wetting of the solder to the bond pads which is particularly important for higher electrical power or temperature applications. Defects in solder can also occur and grow during operation and thermal cycling. Sonoscan is an attractive non-destructive test to characterize solder joints and is often used to study the growth of defects during life test simulations. X-ray imaging cannot identify very small defects, particularly non-wetting and delamination because of poor resolution. The instrument used in this study was a CSAM (C-Mode Scanning Acoustic Microscopy) operating in reflection mode at 30-100 MHz. We have identified voids inherent in the solder layer as well as delamination at the package to solder and solder to heat-sink interfaces. C-SAM results confirmed that the delamination was caused by CTE mismatch of the materials as well as the mechanical stresses caused by higher level package integration and module assemblies. Thermal cycling studies have shown that typically the voids do not grow whereas delamination does. These results were used to improve thermal heat-sinking and product reliability by minimizing defects in solder joint by changes in process and mechanical designs.

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