scholarly journals Interfacial evolution of pure Sn solder bearing silicon carbide nanowires under isothermal aging and thermal cycling

2021 ◽  
Author(s):  
Mu-lan Li ◽  
Li-li Gao ◽  
Liang Zhang ◽  
Wei-min Long ◽  
Su-juan Zhong ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Thermal Cycling ◽  
Isothermal Aging ◽  
Interfacial Evolution ◽  
Pure Sn

Impact of isothermal aging on fine pitch BGA packages with Sn-Ag-Cu solder interconnects

2010 ◽  
Vol 2010 (1) ◽  
pp. 000298-000305
Author(s):  
Tae-Kyu Lee ◽  
Weidong Xie ◽  
Thomas R. Bieler ◽  
Kuo-Chuan Liu ◽  
Jie Xue
Keyword(s):  
Thermal Cycling ◽  
Microstructure Evolution ◽  
Isothermal Aging ◽  
Substrate Surface ◽  
Solder Interconnects ◽  
Surface Finishes ◽  
Bga Packages ◽  
Fine Pitch ◽  
Solder Balls

The interaction between isothermal aging and long-term reliability of fine pitch ball grid array (BGA) packages with Sn-3.0Ag-0.5Cu (wt%) solder ball interconnects are investigated. In this study, 0.4mm fine pitch packages with 0.3mm diameter Sn-Ag-Cu solder balls are used. Two different die sizes and two different package substrate surface finishes are selected to compare the internal strain impact and alloy effect, especially the Ni effect during thermal cycling. To see the thermal impact on the thermal performance and long-term reliability, the samples are isothermally aged and thermal cycled from 0 to 100°C with a 10minute dwell time. Based on weibull plots for each aging condition, the lifetime of the package reduced approximately 44% with 150°C aging precondition. The microstructure evolution is observed during thermal aging and thermal cycling with different phase microstructure transformations between electrolytic Ni/Au and OSP surface finishes, focusing on the microstructure evolution near the package side interface. Different mechanisms after aging at various conditions are observed, and their impacts on the fatigue life of solder joints are discussed.

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.

scholarly journals Influences of silicon carbide nanowires addition on IMC growth behavior of pure Sn solder during solid-liquid diffusion

2021 ◽  
Author(s):  
Mulan Li ◽  
Liang Zhang ◽  
Jiang Nan ◽  
Sujuan Zhong ◽  
Lei Zhang
Keyword(s):  
Silicon Carbide ◽  
Solder Joint ◽  
Ductile Fracture ◽  
Composite Solder ◽  
Mechanical Performance ◽  
Growth Behavior ◽  
Liquid Diffusion ◽  
Soldering Process ◽  
Solid Liquid ◽  
Pure Sn

Abstract In this paper, various mass fraction (0, 0.2, 0.4, 0.6, 0.8, 1.0 wt%) of silicon carbide nanowires (SiC) were incorporated into pure Sn solder to enhance the performances of Sn solder joint. The wetting behavior, shear strength and intermetallic compound (IMC) growth mechanism of Sn-xSiC/Cu solder during solid-liquid diffusion at 250°C was investigated systematically. The experiment results demonstrated that the wettability of Sn-xSiC/Cu solder had a significant improvement when the addition of SiC was up to 0.6 wt%, and excessive additives would degrade the wettability of the composite solder. The formation of the Cu6Sn5 IMC layer was observed at the Sn-xSiC solder/Cu interface. Meanwhile, SiC as an additive was conducive to restraining the growth of interfacial IMC during soldering process and the IMC thickness overtly fell down after doping 0.8 wt% SiC into Sn solder. Moreover, SiC addition would contribute to enhancing the mechanical performance of Sn solder joint. The fracture mechanism of solder joint changed from a mix of brittle and ductile fracture to a characteristic of typical ductile fracture.

An Evaluation of Containment Materials for High Temperature Metal Thermal Storage

2015 ◽  
Author(s):  
David Curran ◽  
Fletcher Miller ◽  
Russell Carrington ◽  
Arlon Hunt
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Energy Storage ◽  
Thermal Cycling ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Research Team ◽  
Levelized Cost Of Electricity ◽  
Containment Vessel

Concentrated solar power (CSP) must decrease its levelized cost of electricity (LCOE) below the DOE SunShot program targets of 6 ¢/kWhe and improve its reliability to enable widespread adoption. Two features of CSP that will decrease LCOE and improve reliability are higher operating temperatures for the power cycle and thermal energy storage (TES). Thermaphase Energy and San Diego State University are developing the Liquid Metal Thermal Energy Storage System (LiMTESS), an innovative TES system based on phase change in Al-Si and Mg-Si alloys that stores thermal energy produced by gas-cooled solar receivers at temperatures above 800 C. Proper containment for Al-Si and Mg-Si alloys is critical for LiMTESS commercialization. Any containment vessel must be simultaneously compatible with the molten alloys and high-temperature oxidizing gases (e.g., air), facilitate heat transfer between the alloys and high-temperature oxidizing gases, and accommodate internal stresses associated with TES operation. A ceramic-metallic composite material (TCON) and select ceramics such as siliconized silicon carbide (SiSiC) and alumina initially showed promise in meeting these requirements. A series of thermal cycling tests were performed to check the integrity of the containment vessels. TCON produced macroscopic nodules during the thermal cycling that eliminated it from further consideration. On the other hand, SiSiC performed well when exposed to high-temperature, AlSi36, MgSi56, and air. To further evaluate SiSiC as a containment material, the research team conducted multiple thermal cycles with variable temperature profiles, duration of test, and gas environments. Before and after each thermal cycle, the team conducted a mass analysis and performed SEM and EDS analysis on prepared, treated samples. The results confirm SiSiC is a good candidate for a containment vessel. At this point the research team is evaluating Morcoset, a silicon carbide-based mortar, for creating an air-tight seal for SiSiC. The research team assessed the quality of the seal by using the mortar to seal MgSi56 and conducted thermal cycling tests to compare the mass loss of the system due to Mg vapor escaping the system to that of a controlled system with no alloys sealed. Results confirmed that Mg vapor did not exit the system. There is still more work to do, but preliminary results indicate the Morcoset + SiSiC system is a good containment system for AlSi36/MgSi56. In this paper the results of the long-duration thermal cycling tests as well as electron micrographs of the containment seals and phase change materials are presented.

Reliability Analysis of Aging in Joint Microstructures for Sn-Ag-Cu Solder Joints During Thermal Cycling

2015 ◽  
Author(s):  
Chaobo Shen ◽  
Zhou Hai ◽  
Cong Zhao ◽  
Jiawei Zhang ◽  
M. J. Bozack ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Isothermal Aging ◽  
Solder Joints ◽  
Ball Grid Array ◽  
Test Results ◽  
Continuous Growth ◽  
Relative Fraction ◽  
Fatigue Failures ◽  
Joint Microstructures ◽  
Better Than

This study illustrates test results and comparative literature data on the influence of isothermal aging and thermal cycling associated with Sn-1.0Ag-0.5Cu (SAC105) and Sn-3.0Ag-0.5Cu (SAC305) ball grid array (BGA) solder joints on three board finishes (ImAg, ENIG, ENEPIG). The resulting degradation shows that the characteristic lifetimes for both SAC105 and SAC305 decrease in the order ENIG > ENEPIG > ImAg. SAC305, with a higher relative fraction of Ag3Sn IMC within the solder, performs better than SAC105. SEM and EDX analysis shows continuous growth of Cu-Sn intermetallic compounds (IMC) on SAC/ImAg systems and Cu-Ni-Sn IMC on SAC/ENIG/ENEPIG systems at board side solder joints, which eventually cause fatigue failures.

Package Reliability of the SiC Power Modules in Harsh Environments

2011 ◽  
Vol 2011 (HITEN) ◽  
pp. 000139-000144
Author(s):  
Fengqun Lang ◽  
Hiroshi Yamaguchi ◽  
Hiroshi Sato
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Electrical Resistivity ◽  
Thermal Cycling ◽  
Isothermal Aging ◽  
Harsh Environments ◽  
Die Attach ◽  
Power Modules ◽  
Almost All ◽  
Package Reliability

To evaluate the package reliability of the SiC power modules in harsh environments, the SiC Schottky Barrier Diodes (SBDs) were die bonded to the Si3N4/Cu/Ni(P) substrate with Au-Ge eutectic solder using a vacuum reflow furnace. The Si3N4/Cu/Ni(P) substrates are active metalized copper (AMC). The bonded samples were isothermally aged at 330°C and tested under thermal cycling conditions in the temperature range of −40–300°C in air. During the isothermal aging, cracks of the Ni(P) layer developed, resulting in oxidation of the Cu power path. Decrease in the die bond strength and increase in the electrical resistivity were observed due to the Cu power path oxidation and the growth of the Ni-Ge intermetalic compound (IMC) in the joint. Under the thermal cycling conditions, the metallization of the substrate suffers from serious surface roughness, which greatly degrades the die-attach reliability. The Al electrode was found to seriously exfoliate from the SiC-SBDs due to the thermal stress. After 521 cycles, almost all the Al electrode exfoliated form the anode. Benefit from the excellent mechanical properties of Si3N4, no detachment of the Cu layer was observed from the Si3N4 substrate after 1079 cycles, while the Cu layer detached from the AlN substrate only after 12 cycles.

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