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The Kirkendall void had been a well-known issue for long-term reliability of semiconductor interconnects; while even the KVs exist at the interfaces of Cu and Sn, it may still be able to pass the condition of unbias long-term reliability testing, especially for 2,000 cycles of temperature cycling test and 2,000 h of high temperature storage. A large number of KVs were observed after 200 cycles of temperature cycling test at the intermetallic Cu₃Sn layer which locate between the intermetallic Cu₆Sn₅ and Cu layers. These kinds of voids will grow proportional with the aging time at the initial stage. This paper aims to compare various IMC thickness as a function of stress test, the Cu₃Sn and Cu₆Sn₅ do affected seriously by heat, but Ni₃Sn₄ is not affected by heat or moisture.

The package is the design in the flip chip-chip scale package with bumping process and assembly. The package was put in reliability stress test that followed AEC-Q100 automotive criteria and recorded the IMC growing morphology.

The Cu₆Sn₅ intermetallic compound is the most sensitive to continuous heat which grows from 3 to 10 µm at high temperature storage 2,000 h testing, and the second is Cu₃Sn IMC. Cu₆Sn₅ IMC will convert to Cu₃Sn IMC at initial stage, and then Kirkendall void will be found at the interface of Cu and Cu₃Sn IMC, which has quality concerning issue if the void’s density grows up. The first phase to form and grow into observable thickness for Ni and lead-free interface is Ni₃Sn₄ IMC, and the thickness has little relationship to the environmental stress, as no IMC thickness variation between TCT, uHAST and HTSL stress test. The more the Sn exists, the thicker Ni₃Sn₄ IMC will be derived from this experimental finding compare the Cu/Ni/SnAg cell and Ni/SnAg cell.

The research found that FCCSP can pass automotive criteria that follow AEC-Q100, which give the confidence for upgrading the package type with higher efficiency and complexities of the pin design.

This result will impact to the future automotive package, how to choose the best package methodology and what is the way to do the package. The authors can understand the tolerance for the kind of flip chip package, and the bump structure is then applied for high-end technology.

The overall three kinds of bump structures, Cu/Ni/SnAg, Cu/SnAg and Ni/SnAg, were taken into consideration, and the IMC growing morphology had been recorded. Also, the IMC had changed during the environmental stress, and KV formation was reserved.

The purpose of this study was to better understand the challenges faced by leaders who have demonstrated excellence in integrating technology into teaching and learning in P-12 schools in the United States.

This case study of technology savvy P-12 school principals provides insights into how building leaders overcome digital technology innovation challenges. In the summer of 2017, the authors interviewed 12 of the 18 recipients of the NASSP Digital Principal Award. These principals serve as examples of how to lead schools in the digital age.

Using Bolman and Deal's (2013) conceptual framework, the authors analyzed the data around the four frames (i.e., political, structural, human resources, and symbolic) to understand the challenges of being a digital principal. Bolman and Deal posited leaders who function predominantly in a single frame may miss essential organizational change elements.

The authors recognize several limitations in this study. First, the nominating process for the NASSP Digital Principals award involves an application process. Thus, while these principals were recognized for meeting these criteria, it is possible that these awardees were selected based on their nomination materials rather than on actual longitudinal evidence. Second, this study's data were gathered through interviews. The authors did not gather data through student work samples, teacher and staff interviews, or other data points, but rather the single data point of principal perspectives through interviews.

One silver lining from the pandemic is that leading schools cannot be detangled from the digital needs of diverse stakeholders. As such, digital principalship has become the new norm where the principal leads on a screen, teachers teach on a screen, and students learn on a screen. The award-winning digital principals in this study played an integral role in how they message their school's story, how they navigate and design structures, how they overcome political realities, and how they invest in addressing the needs of individuals.

This study aims to investigate whether gamified elements affect the use behaviour of young people (between age 12 and 25 years) on consumption-related mobile applications.

A survey was conducted on 151 young people between the ages of 12 and 25 years.

The results showed that use behaviour on consumption mobile applications was affected by gamification. Behavioural intention to use was affected by the performance expectancy (PE) and effort expectancy (EE) of mobile application designs. Mobile applications characteristics do not affect behavioural intention to use mobile applications but through the mediator mobile application designs.

This study also proposes mechanisms that explain how mobile apps characteristics affect EE and PE through app designs. Use behaviour is affected by Gamification elements. Affective need and social need link up uses and gratification (U&G) theory and unified theory of acceptance and use of technology (UTAUT)in gamification context. This study confirms the affective need affecting behavioural intention (Thongsri et al., 2018). In this regard, the mechanism between the relationship of affective need and behavioural intention was showed. Affective need through both PE and EE influencing behavioural intention.

Corporations should consider adding gamified elements into consumption-related mobile apps to increasing usage behaviour. Lucky draws, quizzes and games could be built in for mobile apps. Mobile app designs and characteristics could improve user experience by allowing consumers to perform their search and buying processes easily. Mobile app designs will not directly influence “behavioral intention to use” but use behaviour.

Practitioners need to look at the problem from technological and customer perspectives. From technological viewpoint, both mobile apps characteristics and design are important in affecting user behaviour. From customer’s perspective, it would be helpful to add gaming elements to the mobile apps and induce emotion. One may also use visual image to create an immersive experience on the development of storyline. Prospective customers might focus on what is going on in the story and pay less attention on its own logic. Thus, simply lucky draw might not have a true effect since player have its own belief working. A suitable story element could have positive effect on mobile apps use behaviour.

This study is one of the first to examine the association between gamification and use behaviour on consumption-related mobile applications. A new framework was proposed by integrating UTAUT model and U&G theory.

The purpose of this paper is to describe key failure mechanisms observed during the development of the advanced packaging technology. Extensive accelerated stress tests are conducted to collect failure data and understand failure characteristics and failure trends. The results will be useful for design improvement and failure rate predictions.

High density chip scale packages (CSP) are developed to meet the needs for high performance and small form‐factor products, but with reduced process procedures and product cost. Test‐to‐failure approaches are applied to evaluate the failure rate and reliability models instead of compliance qualification testing approaches.

The study shows Cu‐trace cracking failure can be treated as random failures and analyzed using a constant failure rate approach. The acceleration factor for the Cu‐trace cracking failure mechanism exhibits a large power exponent comparing to the parameters used in reference models. In addition, the solder joint failure data collected through the study do not fit well with the well‐known solder fatigue life model. Moreover, the test results affirm the test‐to‐failure approach adopted in data collection is providing more accurate failure characteristics compared to the compliance qualification testing approach.

The paper shows that the reliability performance of package technology can be improved by enhancing the package design, improving manufacturing processes and materials optimization.

This is an original research paper and the test‐to‐failure approach in the reliability study helps provide realistic reliability predictions.

The purpose of this paper is to evaluate the effect of core competencies, namely, transformational leadership (TFL), entrepreneurial competence and technical competence on financial performance through the mediation effect of innovativeness, among owner-managed small and medium-sized enterprises (SMEs) in developing countries.

A research model was developed to test nine research hypotheses. Self-report questionnaires designed for this study were sent to SME owner-managers in Malaysia. A total of 178 completed questionnaires were successfully collected. SPSS and SmartPLS were used to perform the data analysis to test the measurement model and structural model.

This paper provides empirical evidence that behavioural innovativeness mediates the relationship between TFL and financial performance, product innovativeness mediates the relationships among entrepreneurial competence, technical competence and financial performance and process innovativeness mediates the relationship between technical competence and financial performance.

The findings of this study are potentially limited by perceptual measures, cross-sectional data and the risk of response bias from a single informant.

Owner-managed SMEs can focus on developing the core competencies to achieve financial performance through innovative products, processes and behaviours. Policymakers and practitioners can gain fresh insights into the complexity of sustaining the business activities and financial performance of SMEs through the core competencies and innovativeness.

The extant literature has revealed that entrepreneurship, leadership, expertise and innovativeness are considered key factors in promoting financial performance, yet little is known about the combined effects of the core competencies on financial performance through innovativeness for owner-managed SMEs in the context of a developing country. The study makes an important contribution to filling this research gap.

To study the behaviour of voids in PBGA solder joints and their influence on the lifetime of lead‐free solder joints.

The behaviour of voids was studied using micro via and land pad PWBs, PBGA components, and by measuring voids in the solder joints. The lifetimes of solder joints were tested using accelerated temperature tests.

Number of factors affecting the solder joint lifetimes were found. The voids were discovered to have a significantly large influence on the solder joints.

The findings can be used to achieve better soldering results, methods, and designs.

In this paper, the effect and the behaviour of voids were studied profoundly. The findings can be valuable to researchers and process personnel.

A PILGRIMAGE to West Cornwall can be heartily recommended to any librarian in search of rest, fresh air, and complete change from the monotony of town life. Here he will find abundance of interest and novelty in connection with the habits and customs of the ancient Britons still extant, and derive many impressions of pleasure from the magnificent rock scenery with which the coast abounds. Dairy‐farming, tin‐mining, pilchard fishing, druidical monuments, and wild flowers can also be studied with profit; and even Public Libraries, in a condition of arrested development not uncommon in other districts of England. Cornwall is pre‐eminently the county for Public Libraries. Geographically it is remote from the populous parts of England, and the Great‐Western Railway Company, with commendable forethought, have taken enormous pains to maintain this seclusion by a most pitiful and inadequate service of trains. I was once assured by the Public Librarian of Penzance that no thief would ever raid his institution, for the simple reason that it was impossible to get away quick enough to avoid detection ! A place thus difficult to get away from, is manifestly one which requires strong home interests to make it attractive, and, as theatres, music halls, and other light diversions, find little favour in Cornish towns, the Public Library, with its wealth of varied reading, is practically the only after‐dark resource left. But there are other circumstances which make Cornwall an ideal county for a liberal provision of Public Libraries. The decline of the mining industry has driven many of the men away to other centres, such as South Africa, and it is well‐known that, at the present time, more money is coming into the county from exiled sons abroad than is being made locally. There is thus an enormous surplus of that great natural reader— woman—and to her should be offered in profusion plenty of romantic and other reading as a solace and compensation for the loss of her natural companion—man.

The purpose of this paper is to assess the effect of different temperature cycling profiles on the reliability of lead‐free 388 plastic ball grid array (PBGA) packages and to deeply understand crack initiation and propagation.

Temperature cycling of Sn‐3.8Ag‐0.7Cu PBGA packages was carried out at two temperature profiles, the first ranging between −55°C and 100°C (TC1) and the second between 0°C and 100°C (TC2). Crack initiation and propagation was analyzed periodically and totally 7,000 cycles were run for TC1 and 14,500 for TC2. Finite element modeling (FEM), for the analysis of strain and stress, was used to corroborate the experimental results.

The paper finds that TC1 had a characteristic life of 5,415 cycles and TC2 of 14,094 cycles, resulting in an acceleration factor of 2.6 between both profiles. Cracks were first visible for TC1, after 2,500 cycles, and only after 4,000 cycles for TC2. The crack propagation rate was faster for TC1 compared to TC2, and faster at the package side compared to the substrate side. The difference in crack propagation rate between the package side and substrate side was much larger for TC1 compared to TC2. Cracks developed first at the package side, and were also larger compared to the substrate side. The Cu tracks on the substrate side affected the crack propagation sites and behaved as SMD. All cracks propagated through the solder and crack propagation was mainly intergranular. Crack propagation was very random and did not follow the distance to neutral point (DNP) theory. FEM corroborated the experimental results, showing both the same critical location of highest creep strain and the independence of DNP.

Such extensive work on the reliability assessment of Pb‐free 388 PBGA packages has never been performed. This work also corroborates the results from other studies showing the difference in behavior between Pb‐free and Pb‐containing alloys.

Describes Poetry in the Branches, a multi‐layered, replicable program model, devised by Poets House, New York, to foster the link between librarians, the public and the living tradition of poetry. Provides a comprehensive list of titles of contemporary poetry collections by single authors and anthologies.

High‐density packaging devices have unique characteristics which make their assembly, test and repair very difficult. The only realistic method of rework is to replace the defective component with a new or re‐balled component. Although a wide range of rework techniques is available, degradation in assembly reliability may accompany the process. The formation of brittle secondary intermetallic compounds following CSP rework can adversely affect the mechanical properties of the joint, particularly when they make up a significant proportion of its thickness. Reports on the effects of different CSP rework techniques on intermetallic layer formation. Two PCB pad‐cleaning methods and three flux/paste deposition methods are investigated. The reworked joints are analysed using optical microscopy to determine the extent of intermetallic growth. Their quality is also assessed using shear strength testing prior to, and after, thermal ageing at 1008C to accelerate the growth of intermetallic compounds and evolution of the solder grain structure.