Improving shear test performance of SAC305/OSP Cu solder joints by modifying microstructure with minor Ni doping before and after aging

2020 ◽  
Vol 245 ◽  
pp. 122761
Author(s):  
Collin Fleshman ◽  
Rui-wen Song ◽  
Jenq-Gong Duh
Keyword(s):  
Test Performance ◽  
Shear Test ◽  
Solder Joints ◽  
Ni Doping ◽  
Before And After

Voiding and Reliability of Assembly of BGA with SAC and 57Bi42Sn1Ag Alloys

2013 ◽  
Vol 2013 (1) ◽  
pp. 000128-000139 ◽  
Author(s):  
Yan Liu ◽  
Joanna Keck ◽  
Erin Page ◽  
Ning-Cheng Lee
Keyword(s):  
Test Performance ◽  
Shear Test ◽  
Solder Joints ◽  
Low Cost ◽  
Drop Test ◽  
Solder Paste ◽  
Weakest Link ◽  
Solder Bumps ◽  
Pasty Range ◽  
Homogenization Temperatures

Low melting 57Bi42Sn1Ag (BiSnAg) was explored for replacing SAC solders as a low-cost solution. In this study, BGAs with SAC105, SAC305, and BiSnAg balls were assembled with SAC105, SAC305 or 57Bi42Sn1Ag solder paste. Joint mechanical strength, drop test performance, and voiding performance were evaluated against the reflow profile. SnPb was included as a control. The findings are as follows: (1) The microstructure of solder joints showed that, among all of the combinations, only BiSnAg-105 LT and BiSnAg-305 LT exhibited well-distinguishable alloy regions. For SAC-BiSnAg systems, Sn-dendrites were noticeable at LT, while Ag3Sn needles developed at HT. The joints were homogeneous for the rest of the combinations. (2) In the shear test, combinations involving BiSnAg solder were brittle, regardless of the Bi alloy location and reflow profile, as evidenced by stress-strain curves and morphology of the ruptured surface. The strong influence of Bi on the rupture site may have been caused by the stiffening effect of solder due to the homogenized presence of Bi in the joint. With the stiffened solder, the brittle IMC interface became the weakest link upon shearing, although the brittle BiSn crystalline structure also contributed to the rupture. (3) In the drop test, all Bi-containing solder joints performed poorly compared with Bi-free systems, which was consistent with shear test results. Drop numbers increased with increasing elongation at break of solder bumps as measured in the shear test. (4) Voiding was affected by flux chemistry and reduced by low alloy homogenization temperatures and solid top factors, but was increased by low surface tension factor, melting sequence factor, overheating factor and wide pasty range factor. Compared to SAC or SnPb systems, the BiSnAg system is low in voiding if reflowed at LT. In this study, voiding had an insignificant effect on shear strength and drop test performance.

scholarly journals Grooved Pegboard Test Performance Before and After Cerebral-Spinal Fluid Tap Test in Patients with Normal Pressure Hydrocephalus

2020 ◽  
Author(s):  
Caiyan Liu ◽  
Liling Dong ◽  
Chenhui Mao ◽  
Jie Li ◽  
Xinying Huang ◽  
...  
Keyword(s):  
Cognitive Function ◽  
Upper Extremity ◽  
Normal Pressure Hydrocephalus ◽  
Test Performance ◽  
Normal Pressure ◽  
Periventricular White Matter ◽  
Tap Test ◽  
Functional Scores ◽  
Before And After ◽  
Grooved Pegboard Test

Abstract Background Motor impairment in patients with normal pressure hydrocephalus (NPH) can extend beyond gait and include deficits in upper extremity functions and psychomotor speed. Evaluation of upper extremity function will be helpful for NPH patients who are unable to ambulate (e.g., wheelchair-bound patients) and may not be able to comply with the gait evaluation. Our study aimed to explore the use of the grooved pegboard test to assess responsiveness to the cerebrospinal fluid (CSF) tap test in patients with NPH. Methods Seventy-seven possible NPH patients were enrolled from 2013 to 2018. All patients underwent detailed neuropsychological and walking assessments, CSF tap tests, and brain magnetic resonance imaging. The grooved pegboard test results before and after the CSF tap test were compared and correlated with the other clinical assessments. In diffusion tensor imaging analysis, the fractional anisotropy (FA) and mean diffusivity (MD) values of periventricular white matter were measured by the region of interest method and were correlated with pegboard test performance.Results The grooved pegboard test scores significantly improved after the CSF tap test and correlated with patient walking ability, cognitive function, and functional scores (P < 0.01). The improvement ratios in the complex visual motor speed index (i.e., the grooved pegboard test performance combined with the Symbol-Digit Modalities Test performance) were significantly different between the CSF tap test responder and nonresponder groups. The grooved pegboard test times were significantly correlated with the FA values in right periventricular lesions (P=0.017).Conclusions The performance on the grooved pegboard test was related to lower extremity motor ability and cognitive function. It can be used as an alternative evaluation tool for patients who are unable to ambulate and may not be able to comply with the gait evaluation.

Microstructure evolution and microimpact performance of Sn–Ag–Cu solder joints under thermal cycle test

2010 ◽  
Vol 25 (7) ◽  
pp. 1312-1320 ◽  
Author(s):  
Y.L. Huang ◽  
K.L. Lin ◽  
D.S. Liu
Keyword(s):  
Fracture Energy ◽  
Microstructure Evolution ◽  
Thermal Cycle ◽  
Fracture Behavior ◽  
Solder Ball ◽  
Solder Joints ◽  
Whisker Formation ◽  
Structural Variations ◽  
Before And After ◽  
Ball Joints

The microstructure and microimpact performance of Sn1Ag0.1Cu0.02Ni0.05In (SAC101NiIn)/AuNi/Cu solder ball joints were investigated after a thermal cycle test (TCT). The joints show complete bulk fracture behavior before TCT. Moreover, TCT facilitated interfacial fracture behavior with lower fracture energy. The intermetallic compounds (IMCs) formed in the solder joints before and after TCT were investigated. TCT induces a variety of structural variations in the solder joints, including slipping bands, whisker formation, the squeezing of the IMC layer, the formation of cavities, the rotation and pop-up of grain, and the deformation and rotation of the entire joint. The variations in fracture behavior induced by TCT are correlated with the structural variations in the solder joints.

Low Temperature Bonding of High Density Large Area Array Interconnects for 3D Integration

2010 ◽  
Vol 2010 (1) ◽  
pp. 000028-000035 ◽  
Author(s):  
Jason D. Reed ◽  
Matthew Lueck ◽  
Chris Gregory ◽  
Alan Huffman ◽  
John M. Lannon ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cross Sections ◽  
Test Performance ◽  
Stress Testing ◽  
Large Area ◽  
Bond Yield ◽  
Intermetallic Compound Formation ◽  
Before And After ◽  
Individual Bond ◽  
Low Temperature Bonding

The results of bonding and stress testing of Cu/Sn-Cu bonded dice and Cu-Cu thermocompression bonded dice at 10μm and 15μm pitch in large area arrays are shown. The interconnect bonding process pressure and temperature required for the formation of low resistance (&lt;100 mΩ), high yielding (99.99 % individual bond yield), and reliable interconnects is described. In the case of Cu/Sn-Cu, use of a mechanical key was found to improve yield. A run of 22 consecutive bond pairs was made with the mechanical key, resulting in 98 % aggregate channel yield at 10μm pitch in area arrays containing 325,632 individual bonds per die to achieve an interconnect density of 106 / cm2. SEM cross sections of Cu/Sn-Cu and Cu-Cu bonded samples and EDS analysis of Cu/Sn intermetallic compounds both before and after stress testing are presented. The results of thermal cycling and humidity-temperature testing on electrical yield and resistance are presented for Cu/Sn-Cu with underfill. Comparison of the electrical and shear test performance of Cu/Sn-Cu and Cu-Cu is made. Low temperature bonding (at 210°C, below the melting point of tin) is demonstrated to produce high electrical yield, high shear strength and similar intermetallic compound formation to devices bonded at 300°C. The low temperature process may prove useful for integrating IC devices that have low thermal budgets.

Mechanical Property Evaluation of Sn-3.0A-0.5Cu BGA Solder Joints Using High-Speed Ball Shear Test

2009 ◽  
Vol 38 (12) ◽  
pp. 2489-2495 ◽  
Author(s):  
Sang-Su Ha ◽  
Jin-Kyu Jang ◽  
Sang-Ok Ha ◽  
Jong-Woong Kim ◽  
Jeong-Won Yoon ◽  
...  
Keyword(s):  
Mechanical Property ◽  
High Speed ◽  
Shear Test ◽  
Solder Joints ◽  
Ball Shear ◽  
Property Evaluation ◽  
Ball Shear Test

Outcome assessment of a computer-animated model for learning about the regulation of glomerular filtration rate

2010 ◽  
Vol 34 (2) ◽  
pp. 97-105 ◽  
Author(s):  
Jody L. Gookin ◽  
Dan McWhorter ◽  
Shelly Vaden ◽  
Lysa Posner
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Test Performance ◽  
Visual Memory ◽  
Filtration Rate ◽  
First Year ◽  
Veterinary Students ◽  
Advanced Students ◽  
Before And After ◽  
Written Materials

The regulation of the glomerular filtration rate (GFR) is a particularly important and challenging concept for students to integrate into a memorable framework for building further knowledge and solving clinical problems. In this study, 76 first-year veterinary students and 19 veterinarians in clinical specialty training (house officers) participated in separate online exercises to evaluate the use of a computer-animated model of GFR regulation ( www.aamc.org/mededportal ) on learning outcome. Students were randomly allocated to study either the animated model or written materials before completion of a 10-question multiple-choice quiz. House officers completed a 35-question test before and after study of the animated model. Both groups completed a survey about the learning exercise. The ability of the model to enhance learning was demonstrated by a significant improvement ( P < 0.001) in the test performance of house officers after studying the model. The model performed similarly to written materials alone in affecting the subsequent quiz performance of the students. The majority of students and house officers agreed or strongly agreed that the animated model was easy to understand, improved their knowledge and appreciation of the importance of GFR regulation, and that they would recommend the model to peers. Most students [63 of 76 students (83%)] responded that they would prefer the use of the animated model alone over the study of written materials but acknowledged that a combination of hardcopy written notes and the animated model would be ideal. A greater applicability of the model to more advanced students and an introduction in a didactic setting before individual study were suggested by the house officers. The results of this study suggest that the animated model is a useful, effective, and well-received tool for learning and creating a visual memory of the regulatory mechanisms of GFR.

Hormonal, Physiological, and Physical Performance During Simulated Kickboxing Combat: Differences Between Winners and Losers

2016 ◽  
Vol 11 (4) ◽  
pp. 425-431 ◽  
Author(s):  
Ibrahim Ouergui ◽  
Philip Davis ◽  
Nizar Houcine ◽  
Hamza Marzouki ◽  
Monia Zaouali ◽  
...  
Keyword(s):  
Test Performance ◽  
High Intensity ◽  
Perceived Exertion ◽  
National Level ◽  
Wingate Test ◽  
Rating Of Perceived Exertion ◽  
Upper Body ◽  
Before And After ◽  
Mental Abilities ◽  
Physical Responses

The aim of the current study was to investigate the hormonal, physiological, and physical responses of simulated kickboxing competition and evaluate if there was a difference between winners and losers. Twenty athletes of regional and national level participated in the study (mean ± SD age 21.3 ± 2.7 y, height 170.0 ± 5.0 cm). Hormone (cortisol, testosterone, growth hormone), blood lactate [La], and glucose concentrations, as well as upper-body Wingate test and countermovement-jump (CMJ) performances, were measured before and after combats. Heart rate (HR) was measured throughout rounds 1, 2, and 3 and rating of perceived exertion (RPE) was taken after each round. All combats were recorded and analyzed to determine the length of different activity phases (high-intensity, low-intensity, and referee pause) and the frequency of techniques. Hormones, glucose, [La], HR, and RPE increased (all P < .001) precombat to postcombat, while a decrease was observed for CMJ, Wingate test performance, body mass (all P < .001), and time of high-intensity activities (P = .005). There was no difference between winners and losers for hormonal, physiological, and physical variables (P > .05). However, winners executed more jab cross, total punches, roundhouse kicks, total kicks, and total attacking techniques (all P < .042) than losers. Kickboxing is an intermittent physically demanding sport that induces changes in the stress-related hormones soliciting the anaerobic lactic system. Training should be oriented to enhance kickboxers’ anaerobic lactic fitness and their ability to strike at a sufficient rate. Further investigation is needed to identify possible differences in tactical and mental abilities that offer some insight into what makes winners winners.

Solder joint quality evaluation based on heating factor

Circuit World ◽  
2018 ◽  
Vol 44 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Petr Veselý ◽  
Eva Horynová ◽  
Jiří Starý ◽  
David Bušek ◽  
Karel Dušek ◽  
...  
Keyword(s):  
Shear Strength ◽  
Solder Alloy ◽  
Isothermal Aging ◽  
Solder Joints ◽  
Strength Increase ◽  
Technological Parameters ◽  
Content Type ◽  
Soldering Process ◽  
Before And After ◽  
Joint Quality

Purpose The purpose of this paper is to increase the reliability of manufactured electronics and to reveal reliability significant factors. The experiments were focused especially on the influence of the reflow oven parameters presented by a heating factor. Design/methodology/approach The shear strength of the surface mount device (SMD) resistors and their joint resistance were analyzed. The resistors were assembled with two Sn/Ag/Cu-based and one Bi-based solder pastes, and the analysis was done for several values of the heating factor and before and after isothermal aging. The measurement of thickness of intermetallic compounds was conducted on the micro-sections of the solder joints. Findings The shear strength of solder joints based on the Sn/Ag/Cu-based solder alloy started to decline after the heating factor reached the value of 500 s · K, whereas the shear strength of the solder alloy based on the Bi alloy (in the measured range) always increased with an increase in the heating factor. Also, the Bi-based solder joints showed shear strength increase after isothermal aging in contrast to Sn/Ag/Cu-based solder joints, which showed shear strength decrease. Originality/value The interpretation of the results of such a comprehensive measurement leads to a better understanding of the mutual relation between reliability and other technological parameters such as solder alloy type, surface finish and parameters of the soldering process.

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