Manufacturability and Reliability Screening of Lower Melting Point, Pb-Free Alloys Containing Bismuth

2015 ◽  
Vol 12 (1) ◽  
pp. 1-28 ◽  
Author(s):  
Joseph M. Juarez ◽  
Polina Snugovsky ◽  
Eva Kosiba ◽  
Zohreh Bagheri ◽  
Subramaniam Suthakaran ◽  
...  
Keyword(s):  
High Reliability ◽  
Temperature Cycling ◽  
Vibration Testing ◽  
Excellent Performance ◽  
Test Conditions ◽  
Surface Finishes ◽  
Before And After ◽  
Microstructure Examination ◽  
Lower Melting Point ◽  
Failure Monitoring

This paper explores the manufacturability and reliability of three Pb-free Bi-containing alloys in comparison with conventional SAC305 and SnPb assemblies. The first alloy included in the study is a Sn-based alloy with 3.4%Ag and 4.8%Bi, which showed promising results in the National Center for Manufacturing Sciences and German Joint projects. The other two alloy variations have reduced Ag content, with and without Cu. BGA and leaded components were assembled on medium-complexity test vehicles using these alloys, as well as SAC305 and SnPb as baseline alloys, for comparison. Test vehicles were manufactured using two board materials, 170°C glass transition temperature (Tg) and 155°C Tg, with three surface finishes: ENIG, ENEPIG, and OSP. The accelerated temperature cycling (ATC) testing was done at −55°C to 125°C with 30-min dwells and 10°C/min ramps, for 3,000 cycles. Detailed microstructure examination before and after ATC testing is described, as is failure analysis. All three experimental alloys showed excellent performance in harsh-environment thermal cycling. Vibration testing at two G-force test conditions with resistance failure monitoring was performed on the daisy-chained components. A detailed description of the technique for the vibration testing using 2 G and 5 G harmonic dwells is provided. The lowest failure rate found at both the 2 G and 5 G levels was for the Cu-containing alloy known as Violet. These results provide data for further statistical analysis leading to the choice of proper combinations of the solder alloys, board materials, and surface finishes for high-reliability applications.

Intermittent Failures in High Pin Count Packaging

2006 ◽  
Author(s):  
Ramesh Varma ◽  
Richard Brooks ◽  
Ronald Twist ◽  
James Arnold ◽  
Cleston Messick
Keyword(s):  
Failure Analysis ◽  
Shape Analysis ◽  
State Of The Art ◽  
Process Variation ◽  
High Reliability ◽  
Temperature Cycling ◽  
Assembly Process ◽  
System Failures ◽  
Industrial Grade ◽  
Corrective Actions

Abstract In a prequalification effort to evaluate the assembly process for the industrial grade high pin count devices for use in a high reliability application, one device exhibited characteristics that, without corrective actions and/or extensive screening, may lead to intermittent system failures and unacceptable reliability. Five methodologies confirmed this conclusion: (1) low post-decapsulation wire pull results; (2) bond shape analysis showed process variation; (3) Failure Analysis (FA) using state of the art equipment determined the root causes and verified the low wire pull results; (4) temperature cycling parts while monitoring, showed intermittent failures, and (5) parts tested from other vendors using the same techniques passed all limits.

Reproducibility of velocity-dependent power: before and after lengthening contractions

2011 ◽  
Vol 36 (5) ◽  
pp. 626-633 ◽  
Author(s):  
Geoffrey A. Power ◽  
Brian H. Dalton ◽  
Charles L. Rice ◽  
Anthony A. Vandervoort
Keyword(s):  
Peak Power ◽  
High Reliability ◽  
Similar Amount ◽  
Shortening Velocity ◽  
Lengthening Contractions ◽  
Isokinetic Testing ◽  
Typical Error ◽  
Before And After ◽  
Absolute Reliability ◽  
Ankle Dorsiflexors

The determination of power using isokinetic testing has been shown to be highly reliable. However, isotonic and isokinetic testing involve specific mechanical constraints that likely necessitate different neuromuscular strategies. Therefore, the purpose here was to establish test–retest intrarater reliability (separated by 7 days) of loaded maximal shortening velocity and velocity-dependent power of the ankle dorsiflexors using the isotonic mode of the Biodex dynamometer (i) at baseline and (ii) throughout recovery following 150 high-intensity lengthening contractions. Intraclass correlation coefficients (ICC)2,1 with 95% CIs were used to determine relative reliability, whereas absolute reliability included typical error (TEM) and typical error expressed as a coefficient of variation (TEMCV). Twenty-four young men and women volunteered for the study. Maximal shortening velocity and power were determined with a fixed resistance set at 20% of maximal voluntary isometric contraction across 2 testing sessions separated by 7 days. ICCs were 0.93 and 0.98 for maximal shortening velocity and peak power, respectively. Following the lengthening contractions, ICCs indicated high reliability for maximal shortening velocity and peak power, 0.86 and 0.94, respectively, suggesting that a similar amount of fatigue was incurred on both days. Measures of absolute reliability for maximal shortening velocity and peak power also yielded high reliability. The isotonic mode is highly reliable when testing velocity-dependent power of the ankle dorsiflexors at baseline and following fatiguing lengthening contractions. The high reliability of this measure is encouraging and suggests that the isotonic mode can be used in various settings to track group changes before and after training and following fatigue and lengthening contractions.

Colour stability of surface finishes on thermally modified beech wood

2021 ◽  
Vol 114 ◽  
pp. 116-124
Author(s):  
Gabriela Slabejová ◽  
MÁRIA ŠMIDRIAKOVÁ
Keyword(s):  
Surface Finish ◽  
Beech Wood ◽  
Surface Finishing ◽  
Colour Stability ◽  
Colour Difference ◽  
Surface Finishes ◽  
Before And After ◽  
Thermally Modified Wood ◽  
Wood Surfaces ◽  
Modified Wood

Colour stability of surface finishes on thermally modified beech wood. The paper deals with the influence of the type of transparent surface finish on the change of colour of the surfaces of native beech wood and thermally modified wood. At the same time, the colour stability of three surface finishes on the surfaces of native and thermally modified beech wood was monitored. Beech wood was thermally modified at temperature of 125 °C for 6 hours. The thermal treatment was performed in a pressure autoclave APDZ 240, by the company Sundermann s.r.o in Banská Štiavnica. Three various types of surface finishes (synthetic, wax-oil, water-based) were applied onto the wood surfaces. The colour of the surfaces of native wood and thermally modified wood was measured in the system CIELab before and after surface finishing; the coordinates L*, a*, b*, C*ab and h*ab were measured. From the coordinates measured before and after surface finishing, the differences were calculated and then the colour difference ∆E* was calculated. Subsequently, the test specimens with the surface finishes were exposed to natural sunlight, behind glass in the interior for 60 days. The surface colour was measured at specified time of the exposure (10, 20, 30, 60 days). The results showed that the colour of the wood surfaces changed after application of the individual surface finishes; and the colour difference reached a change visible with a medium quality filter up to a high colour difference. The wax-oil surface finish caused a high colour difference on native wood and on thermally modified wood as well. On native beech wood, the lowest colour difference after exposure to sunlight was noticeable on the synthetic surface finish. On the surface of wood thermally modified, after exposure to sunlight, the lowest colour difference was noticeable on the surface with no surface finish.

Abstract 199: Hardwiring Institutional Learning Through Team-Based Problem-Solving in a Pediatric Cardiovascular Intensive Care Unit

2012 ◽  
Vol 5 (suppl_1) ◽  
Author(s):  
Eric A Williams ◽  
Lauren Ladwig ◽  
De Ann Nikolai ◽  
Gay Matthews ◽  
Jeanine M Graf
Keyword(s):  
Problem Solving ◽  
Real Time ◽  
Task Force ◽  
High Reliability ◽  
Ease Of Use ◽  
Practice Change ◽  
Frontline Staff ◽  
Pareto Chart ◽  
Exact Test ◽  
Before And After

Introduction: Our purpose was to develop a high reliability system (The SWARM) to empower frontline staff to share information regarding communication and process inefficiencies to rapidly develop solutions. Hypothesis: A systematic process for recognition, evaluation, and transparent feedback would increase the use of problem-solving. Methods: A multidisciplinary team, led by a physician and nurse, developed an email strategy to let frontline staff identify problems in real-time and solve and spread this knowledge throughout the CVICU and Heart Center. Problems submitted were outside the scope of institutional patient safety reporting. Unless immediate attention was required, the SWARM team evaluated entries weekly. Entries were categorized as: 1) Useful information to share with ICU staff; 2) More information needed to be obtained and personnel consulted; or 3) A multidisciplinary task force needed to generate consensus and evidence-based guidelines. Solutions were shared with ICU staff via direct email and a monthly newsletter. After 6 months ICU staff were surveyed with 5 questions regarding awareness, utility, and ease of use of the SWARM process. Staff were resurveyed after re-education and institution of leadership walk-rounds. Rates of SWARM entries before and after re-education were compared using Fisher’s Exact Test for proportions.*p<.05 Results: Of the total 65 SWARM entries, 9% were level 1, 86% were level 2 and 5% were level 3. Entries were categorized into problem types and are shown in the Pareto Chart as percent of total(See Chart). Pre- and post- survey results indicated that staff awareness increased from 70% to 91% and staff understanding of utility increased from 57% to 75%. After re-education, use in CVICU increased by 417% (0.7/week to 2.9/week)*. The increased rate of use of the SWARM system has been sustained for 8 weeks post education. The current rate is 1.8/week. The top two Solutions by category were Re-Education (62%) and Practice Change (17%). Conclusions: A system was developed to better manage quality through real-time awareness of our performance. The formal creation of a standardized context for information sharing has resulted in a significant increase in the performance of problem-solving. This multidisciplinary effort allows for minimizing unnecessary variation in how quality improvement efforts are identified and performed.

Embedded Die Packages and Modules for Power Electronics Applications

2016 ◽  
Vol 2016 (DPC) ◽  
pp. 001918-001947 ◽  
Author(s):  
Lars Boettcher ◽  
S. Karaszkiewicz ◽  
D. Manessis ◽  
A. Ostmann
Keyword(s):  
Power Electronics ◽  
Power Efficiency ◽  
High Reliability ◽  
Heat Removal ◽  
Testing Temperature ◽  
Temperature Cycling ◽  
Switching Frequency ◽  
Large Area ◽  
Power Modules ◽  
Embedded Power

Packages and modules with embedded semiconductor dies are of interest for various application fields and power classes. First packages in the lower power range are available in volume production since almost six years. Recent developments focus on medium and higher power applications raging over 500W into the kW range. Different approaches are available to realize such packages and modules. This paper will give an overview and detailed description of the latest approaches for such embedded die structures. In common of all of these approaches, is the use of laminate based die embedding, which uses standard PCB manufacturing technologies. Main differences are the used base substrate, which can still be a ceramic (DBC), Cu leadframe or high current substrate. Examples for the different methods will be given. As the main part, this paper will describe concepts, which enable significant smaller form-factor of power electronics modules, thereby allowing for lower price, high reliability, capability of direct mounting on e.g. a motor so as to form one unit with the motor housing, wide switching frequency range (for large application field) and high power efficiency. The innovative character of this packaging concept is the idea to embed the power drive components (IGBTs, MOSFETs, diode) as thinned chips into epoxy-resin layer built-up and to realize large-area interconnections on both sides by direct copper plating the dies to form a conductor structure with lowest possible electrical impedance and to achieve an optimum heat removal. In this way a thin core is formed on a large panel format which is called Embedded Power Core. The paper will specifically highlight the first results on manufacturing an embedded power discrete package as an example of an embedded power core containing a thin rectifier diode. For module realization, the power cores are interconnected to insulated metal substrates (IMS) by the use of Ag sintering interconnection technologies for the final manufacturing of Power modules. The paper will elaborate on the sintering process for Power Core/IMS interconnections, the microscopically features of the sintered interfaces, and the lateral filling of the sintering gap with epoxy prepregs. Firstly, 500W power modules were manufactured using this approach. Reliability testing results, solder reflow testing, temperature cycling test and active power cycling, will be discussed in detail.

A 300°C High Reliability HALT/HAST Screening/Sorting Procedure for Ceramic Capacitors

2018 ◽  
Vol 2018 (HiTEC) ◽  
pp. 000129-000137 ◽  
Author(s):  
Harold L. Snyder
Keyword(s):  
High Reliability ◽  
Stress Test ◽  
Electrical Current ◽  
Accelerated Life Test ◽  
Test Results ◽  
Electrical Model ◽  
Current Leakage ◽  
Ceramic Capacitor ◽  
Ceramic Capacitors ◽  
Before And After

Abstract A highly accelerated life test (HALT) and highly accelerated stress test (HAST) procedure for ceramic capacitors developed by the author in the mid 1980's to early 1990's, and published in 1994, consists of a 400 Volt biased six (6) hour stress sort at 150°C (423K), a methanol current leakage test that located mechanical and structural cracks, a visual inspection at ten times (10×) magnification, and a capacitance and dissipation measurement before and after the test. In over thirty (30) years of use, there has never been a user reported in-circuit failure in industrial, military, and aerospace application at temperatures as high as 500°C (773K). However, reviewing user feedback, two concerns with the original sorting procedure are the stress is performed at 150°C (423K), and the lack of a more detailed ceramic capacitor electrical model. To address the first, the low aging temperature, the stress temperature was increased from 150°C to 300°C, in order to age ceramic solid state crystal mineral phases that may change with temperature. The test results for X7R and NP0/COG multilayer ceramic capacitors (MLCC) at 300°C, are compared to the test results using the original HALT/HAST procedure at 150°C. Differences between X7R/NP0/COG and porcelain capacitors are discussed when applicable. Further, a more detailed ceramic capacitor electrical model that represents the physical and electrical characteristics of the ceramic capacitors is presented, including the electrical current leakage effects with temperature, and the carbonized residue effects from the manufacturing process.

A STUDY OF SURFACE FINISHES FOR IC SUBSTRATES AND WIRE BOND APPLICATIONS

2011 ◽  
Vol 2011 (1) ◽  
pp. 000516-000520 ◽  
Author(s):  
John Ganjei ◽  
Ernest Long ◽  
Lenora Toscano
Keyword(s):  
Surface Finish ◽  
Printed Circuit Boards ◽  
Performance Enhancement ◽  
High Reliability ◽  
Cost Effective ◽  
Electroless Nickel ◽  
Gold Wire ◽  
Electronics Industry ◽  
Surface Finishes ◽  
And Performance

The continuing drive for ever increasing performance enhancement in the electronics industry, in combination with the recent, very significant increase in precious metal costs have left fabricators and OEMs questioning what the best, most cost effective, surface finish is for high reliability applications. Currently, the IC substrate market relies heavily on electrolytic nickel and gold as a solderable and superior wire bondable surface. The use of this finish has allowed manufacturers to avoid the reliability concerns However, this choice also results in significant design restraints being imposed. Many in the industry are now investigating the use of electroless nickel/electroless palladium/immersion gold (ENEPIG) to achieve both high reliability and performance, without the negative design restraints imparted by the use of electrolytic processes. However, over the last year alone, the industry has watched the price of gold increase by 50% and that of palladium double [1]. With this in mind, and considering the historic precedent set in the mid 1990’s when ENEPIG was also evaluated as a surface finish for printed circuit boards, when coincidentally, the cost of palladium also reached an all time high, it should be remembered that the electronics industry quickly moved to evaluate alternate, more cost sustainable, surface finishes. This paper details the use of lower cost, alternate surface finishes for IC substrate applications, with particular experimental focus on gold wire bonding capabilities and BGA solderability of the finishes described. The paper also discusses related process cycle advantages and the significantly reduced operating costs associated with these new finishes.

Technologies and Trends to Improve Power Electronic Packaging

2011 ◽  
Vol 2011 (1) ◽  
pp. 000430-000437
Author(s):  
M. Schneider-Ramelow ◽  
M. Hutter ◽  
H. Oppermann ◽  
J.-M. Göhre ◽  
S. Schmitz ◽  
...  
Keyword(s):  
High Reliability ◽  
Transient Liquid Phase ◽  
Wire Bonding ◽  
Temperature Cycling ◽  
Material Behavior ◽  
Process Selection ◽  
Chip Surface ◽  
Bonding Parameters ◽  
Strong Trend ◽  
Die Attach

In the realm of power modules a strong trend toward high temperature and high reliability applications can be observed, which entails new technological challenges, especially for the assembly and packaging of power semiconductors. Because of the well known failure mechanisms of established lead-free standard soldering and heavy aluminum wire bonding technologies, such as fatigue and creep of die attach material and wire bonds at thermal cycling, academic and industrial research focuses on more reliable interconnection technologies. A priority is the research of alternative top and bottom side chip interconnection materials or technologies to improve the temperature cycling capability of power chips that are typically assembled on ceramic substrates. The scientific focus is on Ag sintering as die attach and/or heavy ribbon bonding, for example with Al or bi-metal (Al-Cu). Another focus is the material behavior of ribbon bonds in combination with bonding machine improvements (higher bonding parameters, cutting tool). But there are other very promising technologies like transient liquid phase bonding, for example with Cu-Sn or Ag-Sn systems or Cu heavy wire bonding (up to 400 μm wire diameter) or Cu/Al-Bi metal ribbon bonding. Challenges posed by these technologies have to be discussed focusing on materials and process selection and reliability issues. Process temperatures and temperature profiles must be optimized, wire bonding machines and the chip surface structures as well as finish metallizations need to be adapted. This paper will give an overview of alternative power chip interconnection technologies and discuss the challenges related to processing and reliability.

Mechanical and Thermal Board Level Reliability Comparison Between Electroless Ni Im. Au and Solder on Pad Surface Finishes for Large Flip Chip BGA Packages

2006 ◽  
Author(s):  
Gnyaneshwar Ramakrishna ◽  
Donghyun Kim ◽  
Mudasir Ahamad ◽  
Lavanya Gopalakrishnan ◽  
Mason Hu ◽  
...  
Keyword(s):  
Surface Finish ◽  
Flip Chip ◽  
High Reliability ◽  
Electroless Nickel ◽  
Temperature Cycling ◽  
Design Parameters ◽  
Temperature Cycle ◽  
Bga Packages ◽  
Reliability And Robustness ◽  
Board Level

Large Flip Chip BGA (FCBGA) packages are needed in high pin out applications (&gt;1800), e.g., ASIC's and are typically used in high reliability and robustness applications. Hence understanding the package reliability and robustness becomes one of paramount importance for efficient product design. There are various aspects to the package that need to be understood, to ensure an effective design. The focus of this paper is to understand the BGA reliability of the package with particular reference to comparison of the surface finish, vis-a`-vis, between Electroless Nickel Immersion Gold (ENIG) and Solder On Pad (SOP) on the substrate side of the package, which are the typical solutions for large plastic FC-BGA packages. Tests, which include board level temperature cycling, monotonic bend and shock testing have been conducted to compare the two surface finish options. The results of these tests demonstrate that the mechanical strength of the interface exceeds by a factor of two for the SOP surface finish, while BGA design parameters play a key role in ensuring comparative temperature cycle reliability in comparison with ENIG packages.

Formulation and Evaluation of Antifungal Shampoo Containing Modified Coconut Oil for Tinea Capitis Treatment

2019 ◽  
Vol 819 ◽  
pp. 130-135
Author(s):  
Sukannika Tubtimsri ◽  
Napaachanan Saewon ◽  
Napatsakorn Khonsungdee ◽  
Ramida Rodjanabumrungwong ◽  
Sontaya Limmatvapirat
Keyword(s):  
Tinea Capitis ◽  
Flow Behavior ◽  
Coconut Oil ◽  
Temperature Cycling ◽  
Lauryl Sulfate ◽  
Surfactant Mixtures ◽  
Sorbitan Monolaurate ◽  
Factors Affecting ◽  
Before And After ◽  
Fungi Infection

Modified coconut oil (MCO) has been reported as a promising material for eradication of various fungi which are the primary causes of tinea capitis. The antifungal shampoo is reported as an effective adjuvant therapy for fungi infection. In order to develop MCO as an active ingredient in antifungal shampoo, formulation factors affecting the physical and antifungal properties of shampoo including type and amount of surfactants were investigated. The results indicated that formula containing triethanolamine lauryl sulfate (TLE), ranging from 40-70% w/w, showed the most transparency and stable among the primary surfactants used, suggesting the good compatibility with MCO. An addition of polyoxyethylene 20 sorbitan monolaurate (PSL), an auxiliary surfactant, in the range from 5-40%w/w could enhance the clearness of shampoo while the suitable amount of PSL is also depended on TLE concentration. Various surfactant mixtures of TLE ranging from 40-60%w/w and 20-40% w/w of PSL were selected to formulate MCO shampoo. All formulations of shampoo showed high transparency, effective cleaning action, good stability and Newtonian flow behavior. Moreover, all formulations could inhibit T. rubrum and M. canis both before and after temperature cycling test. Therefore, this study revealed good feasibility of MCO shampoos for tinea capitis treatment.

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