Excellent thermal-cycling stability caused by aging in Fe-doped (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 lead-free piezoceramic

2021 ◽  
Vol 202 ◽  
pp. 113990
Author(s):  
Yanshuang Hao ◽  
Liqiang He ◽  
Shuai Ren ◽  
Yuanchao Ji ◽  
Xiaobing Ren
Keyword(s):  
Thermal Cycling ◽  
Cycling Stability ◽  
Lead Free

Epoxy Underfill Challenges for Copper (Cu) Pillar Solder Bump Packages

2014 ◽  
Vol 2014 (1) ◽  
pp. 000247-000250
Author(s):  
Brian Schmaltz ◽  
Yukinari Abe ◽  
Kazuyuki Kohara
Keyword(s):  
Thermal Cycling ◽  
Solder Ball ◽  
Solder Bump ◽  
High Density ◽  
Lead Free ◽  
Reflow Process ◽  
Stress Concentrations ◽  
Cu Pillar ◽  
Advanced Packaging ◽  
Capillary Underfill

From Eutectic, to Lead Free, to Copper Pillar (Cu) Bumping Technologies. As technology progresses to smaller process generations, new packaging applications are being demanded. The standard solder ball reflow process is being pushed by advancements in copper pillar capped bumps, which in turn allows for high density lead free IO counts at sub 40um bump pitches. Even so, low CTE epoxy materials are still needed in order to dissipate stress concentrations seen during thermal cycling. What challenges await this next technological revision? This presentation will centralize around the latest advancements in epoxy materials for Advanced Packaging Technology; Capillary Underfill (CUF) for narrow pitch Lead Free Copper (Cu) Pillar Solder Bump packages.

Optimisation of FGM TBC and Their Thermal Cycling Stability

2005 ◽  
pp. 9-14
Author(s):  
Michael M. Gasik ◽  
Akira Kawasaki ◽  
Y.S. Kang
Keyword(s):  
Thermal Cycling ◽  
Cycling Stability

FEA Based Reliability Predictions for PBGA Packages Subjected to Isothermal Aging Prior to Thermal Cycling

2015 ◽  
Author(s):  
Munshi Basit ◽  
Mohammad Motalab ◽  
Jeffrey C. Suhling ◽  
John L. Evans ◽  
Pradeep Lall
Keyword(s):  
Finite Element ◽  
Solder Joint ◽  
Thermal Cycling ◽  
Isothermal Aging ◽  
Material Behavior ◽  
Lead Free ◽  
Stress Strain ◽  
Solder Material ◽  
Free Solder ◽  
Temperature Aging

The microstructure, mechanical response, and failure behavior of lead free solder joints in electronic assemblies are constantly evolving when exposed to isothermal aging and/or thermal cycling environments. In our prior work on aging effects, we have demonstrated that the observed material behavior degradations of Sn-Ag-Cu (SAC) lead free solders during room temperature aging (25 C) and elevated temperature aging (50, 75, 100, 125, and 150 C) were unexpectedly large. The measured stress-strain data demonstrated large reductions in stiffness, yield stress, ultimate strength, and strain to failure (up to 50%) during the first 6 months after reflow solidification. In this study, we have used both accelerated life testing and finite element modeling to explore how prior isothermal aging affects the overall reliability of PBGA packages subjected to thermal cycling. In the experimental work, an extensive test matrix of thermal cycling reliability testing has been performed using a test vehicle incorporating several sizes (5, 10, 15, 19 mm) of BGA daisy chain components with 0.4 and 0.8 mm solder joint pitches (SAC305). PCB test boards with 3 different surface finishes (ImAg, ENIG and ENEPIG) were utilized. In this paper, we concentrate on the reporting the results for a PBGA component with 15 mm body size. Before thermal cycling began, the assembled test boards were divided up into test groups that were subjected to several sets of aging conditions (preconditioning) including 0, 6, and 12 months aging at T = 125 °C. After aging, the assemblies were subjected to thermal cycling (−40 to +125 °C) until failure occurred. The Weibull data failure plots have demonstrated that the thermal cycling reliabilities of pre-aged assemblies were significantly less than those of non-aged assemblies. A three-dimensional finite element model of the tested 15 mm PBGA packages was also developed. The cross-sectional details of the solder ball and the internal structure of the BGA were examined by scanning electron microscopy (SEM) to capture the real geometry of the package. Simulations of thermal cycling from −40 to 125 C were performed. To include the effects of aging in the calculations, we have used a revised set of Anand viscoplastic stress-strain relations for the SAC305 Pb-free solder material that includes material parameters that evolve with the thermal history of the solder material. The accumulated plastic work (energy density dissipation) was used is the failure variable; and the Darveaux approach to predict crack initiation and crack growth was applied with aging dependent parameters to estimate the fatigue lives of the studied packages. We have obtained good correlation between our new reliability modeling procedure that includes aging and the measured solder joint reliability data. As expected from our prior studies on degradation of SAC material properties with aging, the reliability reductions were more severe for higher aging temperature and longer aging times.

Thermal cycling stability of thermochemical energy storage system Ca(OH)2/CaO

2018 ◽  
Vol 133 ◽  
pp. 261-268 ◽  
Author(s):  
Liu Dai ◽  
Xin-Feng Long ◽  
Bo Lou ◽  
Juan Wu
Keyword(s):  
Energy Storage ◽  
Thermal Cycling ◽  
Storage System ◽  
Energy Storage System ◽  
Cycling Stability

Thermal Cycling Reliability of Chip Resistor Lead Free Solder Joints

2003 ◽  
Author(s):  
N. Islam ◽  
J. C. Suhling ◽  
P. Lall ◽  
T. Shete ◽  
H. S. Gale ◽  
...  
Keyword(s):  
Solder Joint ◽  
Thermal Cycling ◽  
Fatigue Resistance ◽  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Snagcu Alloy ◽  
Temperature Ranges ◽  
Free Solder

In this study, we have examined the thermal cycling reliability of several lead free chip resistor solder joint configurations. Five sizes of resistors (2512, 1206, 0805, 0603, 0402), 2 temperature ranges (−40 to 125°C and −40 to 150°C), and five different solder types have been examined. The solders include the normal SnAgCu alloy recommended by earlier studies (95.5Sn-3.8Ag-0.7Cu), and several variations that include small percentages of Bismuth and Indium to enhance fatigue resistance. Results have been compared to data for standard 63Sn-37Pb joints.

Pb-Free Process Development for a High End Storage Area Network Application

2007 ◽  
Author(s):  
Sunil Gopakumar ◽  
Francois Billaut ◽  
Eric Fremd ◽  
Manthos Economou
Keyword(s):  
Thermal Cycling ◽  
Cycling Performance ◽  
Lead Free ◽  
Process Window ◽  
Successful Implementation ◽  
Soldering Process ◽  
Wave Soldering ◽  
Free Process ◽  
Plated Through Hole ◽  
The Impact

Lead free solders are being increasingly used in the electronic industry. While most of the electronic products, in terms of volume, are already built lead free, sectors of the industry including high end servers, networking and telecommunications are covered by “lead in solder” exemptions. It is unknown at this point how long these exemptions will last. In addition, many components such as memories have started appearing only in the Pb-free version. As a result, the industry has been pushed to either adopt a mixed assembly process or to transition early to a full Pb-free process. Even though numerous papers have outlined the successful implementation of a Pb-free process, few of them have actually looked at complex high-end multilayer boards in its entirety. This paper focuses on the issues involved in developing an acceptable Pb-free process window for thick, multilayer boards for SMT, Wave soldering, Rework and Press-fit operations. A laminate capable of withstanding Pb-free soldering temperatures was used to construct a 125-mil thick multilayer board with 18 layers which included 8 ground and 10 signal planes. This experiment utilized two popular Pb-free finishes commonly used in the industry: Immersion Silver and high temperature Organic Solderability Preservative (OSP). The widespread SAC 305 alloy with a composition of Sn3.0Ag0.5Cu was used for both SMT and wave soldering. Three sets of assemblies were built: Pb-free, Mixed and Sn/Pb. The mixed assembly mostly used Pb-free components with Sn/Pb solder paste. The impact of increased soldering temperatures on the board, components and reliability of the product were also studied as a part of this research endeavor. Board level reliability tests were conducted by subjecting the boards from 0°C to 100°C Air-to-Air thermal cycling as well as mechanical shock and vibration tests. A suite of reliability and destructive physical analysis (DPA) tests were carried out to establish the quality of the soldering using the eutectic Sn/Pb assembly as the baseline. The study compared the cycling performance of the three sets of assemblies and also looked at the potential impacts of moving to mixed assemblies. Results indicated a reduced process window for Pb-free, especially for the Pb-free wave soldering process due to reduced wetting of the plated through hole barrels as compared to Sn/Pb wave soldering process. The thermal cycling performance of the three sets of assemblies was found to be equivalent after 6000 cycles.

RELIABILITY EVALUATION OF BGA SOLDER JOINTS DURING ACCELERATED LIFE TEST

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4553-4558
Author(s):  
OUK SUB LEE ◽  
NO HOON MYOUNG ◽  
DONG HYEOK KIM ◽  
MAN JAE HUR ◽  
SI WOON HWANG
Keyword(s):  
Solder Joint ◽  
Thermal Cycling ◽  
Solder Joints ◽  
Coefficient Of Thermal Expansion ◽  
Accelerated Life Test ◽  
Lead Free ◽  
Lead Free Solder ◽  
Metal Fatigue ◽  
Mechanical Loads ◽  
Free Solder

The use of BGA (Ball Grid Array) interconnects utilizing the lead-free solder joint has grown rapidly because of its small volume and diversity of application. Thus, it requires the continuous quantification and refinement of lead-free solder joint reliability. The lead-free solder creep and cyclically applied mechanical loads cause metal fatigue on the lead-free solder joint which inevitably leads to an electrical discontinuity. In the field application, BGA solder joints experience mechanical loads during temperature changes caused by power up/down events as the result of the CTE (Coefficient of Thermal Expansion) mismatch between the substrate and the Si die. In this paper, extremely small resistance changes at joint area corresponding to through-cracks generated by thermal fatigue were measured. In this way, the failure was defined in terms of anomalous changes in electrical resistance of the joint. Furthermore the reliability of BGA solder joints in thermal cycling is evaluated by using the modified coffin-Manson criterion which may define and distinguish failure. Any change in circuit resistance according to the accumulated damage induced by the thermal cycling in the joint was recorded and evaluated in order to quantitate reliability of solder joint.

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