bluuebunny/crossref_metadata_2025 huggingface dataset:
Weaponizing Music for Political Contestation and Rivalry in Nigeria
Authors: Duru Adaobi Vivian , Umejei Emeka Lucky , Eke Ikechukwu W.
Published: December 2018

This chapter examines the performative turn in Nigeria's political landscape through an analysis of YouTube videos involving three leading politicians in the country. It argues that Nigerian political actors use dance and music as strategies to wield power. The videos analyzed are the “Conqueror Dance” of Olusegun Obasanjo, a former Nigerian president; the “Elephant Dance” by Bola Ahmed Tinubu, national leader of the ruling All Progressives Congress (APC); and Senator Dino Melaye's “Ajekun Iya Ni Oje.” The authors employed the critical discourse analysis as the conceptual framework and drew on Norman Fairclough's three-dimensional model as the analytical framework to examine the messages inherent in the songs, thus providing insight into the way Nigerian politicians use musical performances to propagate political inequality and abuse of power. The findings suggest that political actors in Nigeria employ tropes as performative devices to entrench mockery, intimidation, threat, vainglory, name-calling, political war and conquest, and imperialism.
A Comparative View of Citizen Engagement in Social Media of Local Governments From North American Countries
Authors: del Mar Gálvez-Rodríhuez María , Haro-de-Rosario Arturo , Caba-Pérez María del Carmen
Published: December 2018

Taking into consideration the growing popularity of social media in North American countries, this chapter aims to perform a comparative analysis of the use of Facebook as a communication strategy for encouraging citizen engagement among local governments in The United States, Canada and Mexico. With regards to the three dimensions used in all regions to measure online citizen engagement, in general terms, the “popularity” and “virality” dimensions are the most common, while the “commitment” dimension is still underutilized. With respect to the significant differences found, Mexican citizens are those that make the best use of the tool “like” to express their support of the information supplied by local governments. Furthermore, in relation to the citizens that are fans of the Facebook pages of local governments, we can observe that Canadian citizens show a greater interest in participating more actively in dialogue building while U.S. citizens are the most willing to disseminate information from their local governments.
Let the Sun Shine In
Authors: Pierard Cindy , Smith Josefine , Wells Caitlin
Published: December 2018

Sunshine Week is a national effort to promote the importance of open government and freedom of information. Although originally begun as a news media initiative, it has grown to include community groups, libraries, schools, governments, and others who are committed to civic engagement and access to information. For academic libraries, Sunshine Week offers opportunities to forge collaborations with campus and community partners, and to connect programming with broader student learning goals. This chapter makes the case for Sunshine Week as a mechanism for bringing together campus and community groups around issues of common concern, either as a standalone effort or part of a broader program focusing on civic engagement. It features a partnership between the library, journalism program, and donors at New Mexico State University but includes ideas and resources that are transferable to other settings.
Information Quality in Participatory Systems
Authors: Touq Ahmed Bin , Ijeh Anthony
Published: December 2018

The study explores the impact of participatory systems on information quality using Abu Dhabi as a case study. Participatory systems are used for deciding social change to affect residents and citizens positively. The case study research method was used to examine information quality in a participatory system. Content of the participatory system was assessed for information quality and it was found to support theoretical claims that Abu Dhabi residents and citizens participate in building sustainable competition using participatory systems. The limitations of the study are found in its focus on a single application, the app CityGuard. Through examining the use of CityGuard, specific issues were recognized which allowed the definition of steps on how its use could impact social change more positively. This paper presents findings from the use of CityGuard as a public participatory tool.
The Arts, Civic Engagement, and Urban Youth
Authors: Grebe Amy M.
Published: December 2018

The Arts, Civic Engagement, and Urban Youth explores methods for using the arts as a vehicle to empower urban youth to become critically engaged in their communities and positively improve their quality of life. Barriers that prevent urban youth from critically engaging social injustices and inequalities are examined and arts-based responses offered. An arts-integrated methodology is woven into previously researched and proposed pathways to civic engagement in order to offer urban youth opportunities for hope and healing from chronic adversity. This arts-integrated methodology facilitates in the development of self-efficacy and knowledge for youth to successfully affect sustainable change in their communities.
When SNS Use Doesn't Trigger E-Participation
Authors: Wakabi Wairagala , Grönlund Åke
Published: December 2018

Numerous scholars have concluded that there is a correlation between use of social network sites (SNS), particularly for news and information acquisition or community building, and the likelihood for e-Participation. This paper examines how the use of Facebook affects the participative behaviours of individuals active in political and interest organizations and those not active in organized politics. Through focus group discussions involving 56 Ugandans, we conclude that in low internet use, authoritarian contexts, the Civic Voluntarism Model and the benefits Facebook brings to participation in Western democracies are turned on their head. Besides overwhelming detachment from politics, even for politically-inclined citizens, low belief in citizens' online actions influencing change and fear of reprisals for criticizing an authoritarian president in power for 29 years, severely dulled the appetite for e-Participation. This high cost of participation means Facebook is growing citizens' civic skills but it is hardly increasing online participation even for politically interested citizens.
The Study of Young People's Civic Participation on the Internet
Authors: Hirzalla Fadi , Banaji Shakuntala
Published: December 2018

This chapter reviews the body of academic literature about young people's online civic participation. It will first sketch how this literature has developed historically in the context of old and changing scholarly discussions about what civic participation and democratic citizenship more generally do or should envelop. The second section outlines how extant empirical studies on young people's civic participation online may be subdivided into four strands of research, each focusing on different questions and relying on different methods. The closing section provides a number of directions for further research, mostly calling for innovative and more pressing context-specific and people-centered research approaches.
Indigenous knowledge and Globalization in Bangladesh
Authors: Islam M. Rezaul
Published: December 2018

This is an example of a PhD proposal based on a qualitative case study. This PhD proposal was completed by the author at the UNESCO Centre for Comparative Education and Research, Faculty of Education, University of Nottingham, United Kingdom. This proposal describes the main elements of a research proposal. First, it provides a background and introduction of the proposal, and then discusses research problem, objectives and research question, significance of the study, conceptual and theoretical aspect. Finally, this proposal outlines the methodology of the study briefly. The proposal also includes a long list of the references used in the study. This will help the students to understand the qualitative study.
Liability or Ethics?
Authors: Snezhko Svetlana , Coskun Ali
Published: December 2018

The purpose of this chapter is to reconsider a traditional approach to the compliance function of firms from a modern perspective, which broadens its concept as a company's liability to only secure its adherence to applicable laws and avoid regulatory sanctions in serving company's interests. The observation of issues regulated by the compliance function in the contest of managing situations of conflict of interest (COI) in different spheres concludes that, in fact, those issues, to a greater extent, relate to sustaining ethical behavior in business rather than stem from regulatory norms. Based on the findings of this analysis as well as other different sources, a new definition for effective compliance has been developed with the focus on adherence to ethical principles in respect to third parties, which addresses compliance function in terms of corporate social responsibility (CSR) and its sustainability role setting a vector for a further research.
Green Marketing and Branding
Authors: Kuscu Asli
Published: December 2018

Green products and services have become an important part of consumption, as consumers' knowledge and concern towards environmental sustainability has increased and they have started to concentrate on their environmental impact. Nonetheless, green marketing still constitutes a small portion of the overall consumer spending. This chapter aims to highlight the importance of marketing activities in the adoption and social normalization of green consumption by the consumers generating public support and economic benefits for the companies as well as environmental and social gains for the society in return. Combining both micro and macro-level determinants and consequences, a conceptual framework is suggested which aims to contribute to literature both theoretically and practically.
The Expected Benefit of Hearing Aids in Quiet as a Function of Hearing Thresholds
Authors: Blamey Peter J.
Published: December 2018

This chapter aimed to estimate speech perception benefits in quiet for clients with different degrees of hearing loss. The difference between aided and unaided scores on a monosyllabic word test presented binaurally was used as the measure of benefit. Retrospective data for 492 hearing aid users with four-frequency pure-tone average hearing losses (PTA) ranging from 5 dB HL to 76 dB HL in the better ear were analyzed using nonlinear regression. The mean benefit for the perception of monosyllabic words in this group of clients was 22.3% and the maximum expected benefit was 33.6% for a PTA of 52 dB HL. The expected benefit can be expressed as a reduction of the error rate by about half for isolated words and about one quarter for sentences across the full range of PTA.
Impact of climate change on rice yield in Sri Lanka: a crop modelling approach using Agriculture Production System Simulator (APSIM)
Authors: Amarasingha R. K. , Suriyagoda L. D. B. , Marambe B. , Galagedara L. W. , Punyawardena R.
Published: December 2018

Climate change will have adverse effects on global food production. Potential reduction in crop productivity will be one of the biggest challenges. The objective of this study was to assess the yield fluctuation using Agriculture Production Systems Simulator (APSIM), based on climate change predictions given by the Intergovernmental Panel on Climate Change (IPCC) in 2014. Rice (Oryza sativa L.) yields were simulated with increasing temperature, CO2 concentration and rainfall for three time periods; 2017 (current), 2050 and 2100. The simulations were run for medium (Bg359) and short (Bg300) duration rice varieties for 9 locations representing Wet Zone, Intermediate Zone and Dry Zone and for both Yala (March to September) and Maha (October to February) seasons. Simulation results revealed that the Wet Zone rice yield of Bg300 decreased in Maha season by 18% and 31% and the Dry Zone rice yield of Bg359 decreased in Yala season by 17%, and 42% for 2050 and 2100, respectively. Therefore, adaptation measures to overcome climate change-induced rice yield reduction in the future are essential to ensure the national food security.
Transthyretin Stimulates Tumor Growth through Regulation of Tumor, Immune, and Endothelial Cells
Authors: Lee Chih-Chun , Ding Xinchun , Zhao Ting , Wu Lingyan , Perkins Susan , Du Hong , Yan Cong
Published: December 2018

Early detection of lung cancer offers an important opportunity to decrease mortality while it is still treatable and curable. Thirteen secretory proteins that are Stat3 downstream gene products were identified as a panel of biomarkers for lung cancer detection in human sera. This panel of biomarkers potentially differentiates different types of lung cancer for classification. Among them, the transthyretin (TTR) concentration was highly increased in human serum of lung cancer patients. TTR concentration was also induced in the serum, bronchoalveolar lavage fluid, alveolar type II epithelial cells, and alveolar myeloid cells of the CCSP-rtTA/(tetO)7-Stat3C lung tumor mouse model. Recombinant TTR stimulated lung tumor cell proliferation and growth, which were mediated by activation of mitogenic and oncogenic molecules. TTR possesses cytokine functions to stimulate myeloid cell differentiation, which are known to play roles in tumor environment. Further analyses showed that TTR treatment enhanced the reactive oxygen species production in myeloid cells and enabled them to become functional myeloid-derived suppressive cells. TTR demonstrated a great influence on a wide spectrum of endothelial cell functions to control tumor and immune cell migration and infiltration. TTR-treated endothelial cells suppressed T cell proliferation. Taken together, these 13 Stat3 downstream inducible secretory protein biomarkers potentially can be used for lung cancer diagnosis, classification, and as clinical targets for lung cancer personalized treatment if their expression levels are increased in a given lung cancer patient in the blood.
Unlocking the full Potential of Lithography for Advanced Packaging
Authors: van der Voort Jelle , van der Stam Michiel
Published: December 2018

Advanced Packaging technologies and applications are developing rapidly in order to support the ever increasing demand for integrating functionality in small and thin devices with low power consumption, high bandwidth, low latency- all at low cost of ownership. Lithography is the key enabling technology for developing and manufacturing such devices. Advanced Packaging processes, in particular Fan-Out, drive towards redistribution patterns with smallest feature sizes of a few micron today and towards 1 micron in the future. These feature sizes must be realized in production processes with multiple layers stacked on top of each other which need to be accurately aligned. In order to meet economic boundary conditions, routine operation on 300 mm wafers (possibly strongly warped) is required with high throughput. Kulicke & Soffa Liteq B.V. developed together with key partners, a novel Lithography system which is focused specifically to meet the challenging requirements of Advanced Packaging, both for current and future applications. The high quality optics used is capable to project the optimally sized reticle field with lowest possible aberrations on the wafer. The system includes Reticle Masking blades (REMA), which delivers high flexibility and high speed for multi-pattern jobs. The magnification of the optics is adjustable for optimal intra-field overlay performance. The reticle is illuminated by a high power UV laser. This novel setup creates many advantages for imaging, Cost of Ownership and throughput. The illumination and projection optics is combined with modern mechatronics to handle warped wafers with minimal overhead times. The design has a strong focus on contamination control. Wafer Edge Processing functions are integrated in the system to support the use of state-of-the-art plating processes. The modularity of the system architecture makes it possible to extend functionality and performance into the future. In this paper we will introduce the novel LITEQ 500 projection stepper, present imaging results and demonstrate the flexibility and high throughput potential of reticle masking for complex multi-pattern jobs.
Advances in Temporary Bonding and Debonding Technologies for use with Wafer-Level System-in-Package (WLSiP) and Fan-Out Wafer-Level Packaging (FOWLP) Processes
Authors: Fowler Michelle , Massey John P. , Koch Matthew , Edwards Kevin , Braun Tanja , Voges Steve , Gernhardt Robert , Wohrmann Markus
Published: December 2018

Today's complex fan-out wafer-level packaging (FOWLP) processes include the use of redistribution layers (RDL) and reconstituted wafers with epoxy mold compound (EMC) for use in heterogeneous integration [1]. Wafer-level system-in-package (WLSiP) uses fan-out wafer-level packaging (FOWLP) to build the system-in-package (SiP) by attaching know-good die (KGD) in a chip-first process to a tape laminated temporary carrier. If the dies are attached in a die-up configuration (active area facing up) and then over-molded with EMC, contact pads on the embedded die are exposed during the backside grind process. During the RDL build, the temporary carrier supplies mechanical support for the thinned substrate. In a die-down configuration with the active area facing down (eWLB), the temporary carrier is removed after the molding process thus exposing the contact pads for RDL build and solder ball mount.

The ideal chip attachment scheme should minimize lateral movement of the die during over-mold (die shift) and also minimize vertical deformation of the bonding material. Thermal release tape provides a convenient way to attach die to a carrier prior to over-molding with EMC. However, not all bonding materials are suitable for presentation in tape form, so the material used in the tape may not be the optimal choice. An alternative method is to directly apply temporary bonding material to the carrier substrate. This enables the use of bonding materials with higher melt viscosity and improved thermal stability, resulting in less vertical deformation during die placement, and reduced die shift during over-molding. The bonding material will ideally have high adhesion to the EMC wafer to prevent delamination in the bond line during downstream processing. Stack stress and warpage is a major concern which causes handling and alignment problems during processing. The bonding material and carrier will need to be specifically suited to minimize the effects of stress in the compound wafer.

Such material must balance rigidity with warp to prevent lateral die shift and deformation induced by coefficient of thermal expansion (CTE) mismatch between the carrier and EMC material [2]. Bonding materials must also have enough adhesion to the EMC material to overcome such stress without bond failure for an associated debond path (such as laser or mechanical release). In this experiment, we will examine a thermoplastic bonding material in combination with different release materials, addressing die shift, and deformation after EMC processing. Successful pairs will then undergo carrier release using either mechanical release or laser ablation release technology.
Solder-Joint Reliability of a Radar Processor for Semi-Autonomous Driving Applications
Authors: Benson Mollie , Carpenter Burton , Mawer Andrew
Published: December 2018

Radar is currently employed in automotive applications to provide the range, angle, and velocity of objects using RF waves (77GHz). This paper outlines solder joint reliability of a specific micro-processor that processes data received from a SRR (short range radar operating from 0.2 to 30 meters). It is a powerful digital signal processing accelerator, which targets safety applications that require a high Automotive Safety Integrity Level (ASIL-B). The paper explores the package design and construction, SMT (surface mount technology) assembly, and board level reliability testing of various BGA pad surface finish and solder ball alloy materials on a 0.65 mm pitch, 10 × 10 mm body 141 MAPBGA (mold array process-ball grid array) package. The package configurations include two BGA pad surface finishes (Ni/Au and OSP [organic solderability protectant]) and three solder alloys (SnAg, SAC405, and SAC-Bi [a Bi containing SAC derivative]). Solder joint reliability analysis was performed through AATS (air-to-air thermal shock) between 40°C and +125°C and JEDEC Drop Testing at 1500G's. Thermal shock was extended until at least 75% of the populations failed, which was well past the points needed to qualify the packages for the intended end-use applications. The evaluations of the micro-processor indicate that the MAPBGA package can meet the ASIL-B specification requirements with optimized combinations of BGA pad surface finish and solder alloy. The focus of this paper was to determine the baseline solder-joint thermal shock and JEDEC drop performance with varied BGA pad surface finish and solder ball alloy materials.
Thin Core Substrate Large Size FCBGA Stress and Thermal Challenges and Characterization
Authors: Sung PoHsien , Hu Ian , Yang Penny , Feng Avis , Chin Shouyi , Shih MengKai , Tarng David , Wang Marwan , Hung CP
Published: December 2018

Recently, high speed communication packages require much larger chip sizes and the increased ball/lead counts (>3000), in order to meet high input/output (I/O) functionality, requires large size substrate (>50×50 mm2) to content it. Comparing with conventional substrate, thin core substrate brings about not only lower thickness of package, lightweight, but also short interconnection distance and good power integrity. For large size FCBGA with thin core, the challenge is how to effectively mitigate the assembly and reliability risks. Generally, it is not easy to control warpage using a stiffener ring or a lid for larger package size. Meanwhile, design for warpage control and TIM/chip interface stress reduction are conflicting in general. In addition, there has higher bump crack risk due to increased die center to bump distance resulted by larger die size. The solder resist opening of substrate and micro ball volume are considered to be the factors for solder bump stress reduction. The research work presented in this paper describes key factors for mitigating several assembly related issues, and the identification of the optimum structure design for successfully manufacturing larger size flip chip packages with thin core substrate.
A comparison of the Cu electrochemical migration behavior between Cu lines with 5 um L/S realized by conventional Semi Additive Process (SAP) and an innovative Excimer Laser Damascene Process
Authors: Gernhardt Robert , Müller Friedrich , Woehrmann Markus , Hichri Habib , Hauck Karin , Arendt Markus , Lang Klaus-Dieter
Published: December 2018

The technological evolution regarding multi-chip integrated Fan-Out packages and chip scale packages (CSPs) with high amounts of I/O demands for even higher routing densities. Conventional used technologies and materials like mask aligner and photosensitive polymers used for semi additive process (SAP) in the BEOL have reached its limits to push the resolution down to two um. New materials and technologies are necessary to overcome these limits. As the routing density increases, so does the reliability requirements. The electrochemical migration between Cu lines cannot be neglected and need to be analyzed as the distance between the Cu lines is decreasing.

A new approach for fine-line multi redistribution layers (RDL) realized by an excimer laser dual damascene process was presented in the past, using laser ablation and Cu chemical mechanical planarization (CMP) to realize embedded Cu lines.

This approach has several advantages regarding the processing but one of the most important characteristics of the damascene approach is the improved electrochemical migration behavior. The Cu lines are partially cladded by the Ti part of the seed layer due to the way of processing. The Ti acts as a barrier layer and inhibits the Cu migration into the surrounding polymer. RDL structures realized by conventional SAP have Ti only under and not between the Cu lines.

In this study different test samples with interdigital structures (resp. interdigital capacitor IDC) with five um line and space width (L/S) were realized to analyze the electrochemical migration behavior between the fingers of the IDC. The samples were realized by SAP and by the excimer laser damascene process and were subsequently tested by the temperature humidity bias (THB) test resp. biased High Accelerated Stress Test (bHAST). With the help of this work, we were able to compare the reliability of both process variants and to demonstrate and prove the reliability of embedded copper lines realized by the excimer laser damascene process.
Copper Oxidation Effect in the EMC/Cu Interfacial Adhesion Improvement for a Novel Copper Interconnection Substrate Application
Authors: Shu Min-Fong , Tseng Yi-Hsiu
Published: December 2018

Copper oxidation structure, cupric oxide (CuO) and cuprous oxide (Cu2O), under Ar/H2 plasma reaction mechanism for the EMC/Cu interface adhesion improvement was studied in this work. This work is utilized TGA to figure out Cu oxidized state and sample preparation, and using plasma treatment Cu oxidation layer to evaluate the EMC/Cu interface adhesion strength by shear testing method. Results show a plasma reduction on Cu oxidation layer provide a better interface adhesion, and the layer structure has a significant composition change, Cu/Cu2O/CuO/EMC → Cu/Cu2O/CuO/Cu2O/EMC. These layer structures were identified by high-resolution TEM mapping with EELS spectrum fitting, it was also verified for CuO reduction to form Cu2O, following the Cu2O hydration would provide much hydrogen-bonding in the EMC/Cu interface. This kind of chain reaction mechanism including CuO reduction and Cu2O hydration was described by 2CuO + H2 → Cu2O +H2O → 2CuOH (hydration molecular). The reaction mechanism of the EMC/Cu bonding has been investigated and verified in this experimental study and our conclusion is that hydrogen bonding on the Cu oxidation layer surface can strengthen the EMC/Cu interface adhesion.
Shear Strength and Thermomechanical Reliability of Sintered Ag Joints Containing low CTE Non-metal Additives for Die Attach
Authors: Fan Guangyu , Labarbera Christine , Lee Ning-Cheng , Clark Colin
Published: December 2018

Ag sintering has been paid attention as an alternative to soldering in die attach for decades, especially for high temperature power electronics packages because of its high melting temperature, highly thermal and electrical conductivity of the sintered silver joints, and low process temperature less than 275°C. The coefficient of thermal expansion (CTE) of silver (19.1ppm/°C), however, is much higher than the silicon die (2.6ppm/°C) and the commonly used alumina substrate (7.2ppm/°C). CTE mismatch of the different materials in the various components in a power electronics package lead to the delamination at the interface between interconnection layer and chips or substrate, and/or cracking of the interconnection layer is one of the mostly common causes of failure of power electronics device during thermal cycling or high temperature operation. In recent years we have been developing a series of silver sinter pastes containing low CTE non-metal particles to reduce or adjust CTE of the sintered joints so as to extend the lifetime and reliability of power electronics device in high temperature applications.

In the present paper, we will report a new set of silver sinter pastes containing micro scale non-metal particles, a sintering process, microstructural morphologies, thermo-mechanical reliability of the sintered joint and effect of the contents of non-metal particles on shear strength of the sintered silver joints bonding an Ag silicon die on Ni/Au DBC substrates. Shear tests on the sintered joints with and/or without the low CTE non-metal additives have been conducted at room temperature, 200, 250, and 300°C. Thermo-mechanical reliability of the sintered joints was evaluated by thermal cycling, thermal shock, high temperature storage tests (HTS), respectively. X-ray inspection and scanning electronic microscopy (SEM) were used to characterize void, crack and microstructure morphologies of the sintered joints with and/or without the additives.
Chip Package Interaction: Understanding of Contributing Factors in Back End of Line (BEoL) Silicon, Cu Pillar Design and Applied Process Improvements
Authors: Kuechenmeister Frank , Breuer Dirk , Geisler Holm , Boehme Bjoern , Machani Kashi Vishwanath , Hecker Michael , Kosgalwies Sven , Cho Jae Kyu , He Dongming , Zhang Xuefeng , Zhao Lily
Published: December 2018

This paper describes major contributing factors to the CPI risk and reveals the mitigation strategy successfully applied jointly by GLOBALFOUNDRIES as the silicon supplier and Qualcomm Technologies, Inc., as the customer responsible for packaging. This strategy involves thermo-mechanical modelling, data collection on wafer level using shear test to assess the BEoL-stability, Cu Pillar process development and optimization. The qualification of these process changes had been completed and implemented in volume production.

The paper also discusses mechanical wafer level and thermo-mechanical package modeling approaches. A model has been applied to determine the critical factors on BEoL stress/strain during the flip-chip assembly reflow process. These factors include for instance the Cu Pillar bump geometry and stack up. The results of the modelling work were used to set up experiments to further mitigate CPI related failure modes in BEoL on the package level.

GLOBALFOUNDRIES and Qualcomm Technologies, Inc., assessed Cu Pillar design related rules such as Cu Pillar diameter and height as well as the Cu Pillar stack up. Process improvements were carried out to reduce the undercut of the barrier underneath the Cu Pillar. The paper reveals how effectively an optimized Cu Pillar design and improved Cu Pillar processing can contribute to the risk mitigation of CPI failure modes in the BEoL for critical package designs and assembly processes with low margin against BEoL fracture during solder reflow.

Furthermore, process improvements applied to enhance the BEoL stack strength were investigated and have been implemented in high-volume production. A strong correlation was established between data collected on wafer level to assess the BEoL strength and data collected on package level.
Packaging and Integration Strategy for mm-Wave Products
Authors: Ray Urmi , Cho NJ , Kim YC , Yoon SW , Choi WK , Marimuthu Pandi
Published: December 2018

This paper is a follow on to the paper presented at the IMAPS 14th International Conference DEVICE PACKAGING and will provide more comprehensive case studies of few different system integration strategies for high frequency packaging. The packaging options vary widely based on the end market requirements, from performance, thermal, types and numbers of antenna arrays as well as the RF transceiver ICs. Tied closely to these performance related requirements is competing trade-offs of reliability, form factor and cost.

We present assessment of packaging structures for (a) high performance mm-Wave network product and (b) consumer/mobile product and (c) automotive radar product. The former (a) is generally not challenged by form factor and can be enhanced by the addition of more antenna arrays and RFICs. However, care has to be taken to address the thermal solutions for effective heat dissipation as well as manufacturability issues as the package size may target ~400mm2 for Gen 1 and double or triple the area for subsequent generations. For (b), the primary drivers are cost and form factor. To manage antenna propagation and losses in a constrained form factor, mobile products generally require antenna in package (AiP) integration. The integration of the antenna within the same package as the RF IC greatly reduces the difficulty at the system level. This approach coupled to aggressive miniaturization of the antenna itself, using the same substrate technologies as the SiP leads to a new class of sub-systems termed Antenna in Package (AiP). This is extremely challenging from design, manufacturability and test perspectives. For example, Fan out wafer level packaging, such as eWLB packaging provides extremely smooth copper surfaces with tight etch tolerance compared to standard laminate based packaging. However, having multiport antenna structures fabricated in fan out technology with inductance matching and efficient ground ports, continue to be problematic. Hence adoption of 3D structures, in conjunction with SIP integration (with inductors and IPDs) can potentially provide relief. Inductors can also be built into the eWLB structure using the RDL as well as in the laminate packages using substrate embedded thin film cores.
Bumping Process Impact on the Chip Package Interaction (CPI) Reliability
Authors: Fu Lei , Bhagavat Milind , Barber Ivor
Published: December 2018

Flip chip technology is widely used in advanced integrated circuit (IC) package. Chip package interaction (CPI) became critical in flip chip technology that needed to be addressed to avoid electrical or mechanical failure in products. When addressing CPI challenges, different areas have to be considered, ranging from silicon BEOL design and processing, bumping design and process, package assembly process, assembly bill of material (BOM), and substrate technology. Controlled collapse chip connection (C4) bump technology provided the inter-connection between the IC to package substrate for high-performance, leading-edge microprocessors. It is very critical for chip package interaction (CPI). With the transfer to lead free technology, bumping process plays more and more important role for chip package interaction reliability.

In this paper, we focused on bumping process effect on the CPI reliability. The bumping process has been reviewed and CPI reliability issues induced by the bumping process like particles, Ti seed layer deposition, UBM undercut, Cu pad oxidation and contamination, photoresist opening damage have been discussed. Bumping process optimization and corrective actions have been taken to reduce those defects and improve CPI reliability.
Lithographic evaluation of thin photoimageable dielectric dry film for advanced panel level packaging applications
Authors: Best Keith , Dimov Ognian , Habib Sudmun , Malik Sanjay
Published: December 2018

This paper presents a new dielectric material capable of resolving 2 to 3μm features that are required for high density advanced packaging applications. The material is applied in dry film format to be conducive to panel-level processing. The material can be processed at temperatures below 170°C and total thermal shrinkage is below 5%, resulting in exceptionally low stress of 11 MPa. The film is thermally stable at temperatures up to 350°C. Mechanical and electrical properties of the material are state of the art.

As the demand for high density packages increases, so will the pressure to lower the cost of manufacturing. Migrating from wafers to large non-circular panels offers several key cost advantages. There are multiple technical challenges that need to be addressed before commercial viability of panel scale manufacturing can be established. A new class of novel dielectric materials will be needed that can be processed at low temperatures and demonstrate low shrinkage to minimize warpage.

In this study, 2 to 3μm patterns were successfully formed using i-line stepper exposure conditions. The process started by laminating a 510mm × 515mm panel with highly photosensitive dielectric film. The laminated panels were exposed at a nominal dose of 125 mJ/cm2. Fine negative tone patterns were created after development. For the metallization of the layer, the seed layer was deposited with titanium-copper sputtering. After the seed formation, trenches were filled with copper by an electrolytic plating process.
Integration of a K-Band Receiver Front-End Using a Copper Core Printed Circuit Board
Authors: Curran Brian , Reyes Jacob , Tschoban Christian , Ndip Ivan , Lang Klaus-Dieter , Leiß Jens , Martinez-Vazquez Marta , Baggen Rens
Published: December 2018

Increasing demand for high bandwidth wireless satellite connections and telecommunications has resulted in interest in steerable antenna arrays in the GHz frequency range. These applications require cost-effective integration technologies for high frequency and high power integrated circuits (ICs) using GaAs, for example. In this paper, an integration platform is proposed, that enables GaAs ICs to be directly placed on a copper core inside cavities of a high frequency laminate for optimal cooling purposes. The platform is used to integrate a K-Band receiver front-end, composed of four GaAs ICs, with linear IF output power for input powers above −40dBm and a temperature of 42°C during operation.
Design of Solder Connections for Self-Assembly of Optoelectronic Devices
Authors: Marinis Thomas F. , Soucy Joseph W.
Published: December 2018

The cost of optoelectronic assemblies is significantly higher than that of electronic assemblies due in large part to the method of assembly. A typical computer circuit board is built by screen printing solder paste onto a printed wiring board, placing components on the board at rates of several thousand per hour, and then reflowing the solder paste in a conveyor oven. By contrast, optoelectronic assemblies are built up in a sequential process in which epoxy is dispensed for a single component, which is placed and held in position until the epoxy is cured. Many minutes are required to build an optoelectronic assembly, such as a laser module, by this approach, also the precision robotic placement tool needed for this process costs in excess of a million dollars. The demand for all types of optoelectronic components in communications, computing, automotive, medical and aerospace applications is great, but the high cost of manufacture is constraining growth, so clearly a better method of assembly is needed.

In surface mount assembly, advantage is taken of the high surface tension of molten solder to self-align ball grid array packages and flip chip die. However, in these applications, the volume of solder applied as paste by stencil printing is not sufficiently well controlled to achieve the precise alignment required for optoelectronic devices. We believe that the requirement on solder volume control for assembly of optoelectronic devices can be relaxed by designing the bond pads so that the height or alignment of connections is controlled by surface tension of the solder rather than its volume. Our design approach to accomplishing this is to connect auxiliary pads to the primary attachment pad, which act as solder reservoirs. Surface tension causes solder to be redistributed among these pads to achieve a uniform pressure throughout the solder volume. This phenomena is governed by the Young-Laplace equation, ΔP = γκ, in which ΔP represents the difference in pressure within and outside the solder, γ the surface tension of the solder and κ the local curvature of the solder surface. Thus, the design of the set of primary and auxiliary pads is critically important to realizing the desired control of joint height. In this paper we describe the use of the Surface Evolver software package in combination with analytical models, to analyze the behavior of various connection configurations with respect to variations in printed solder volume. Specifically, we calculate the equilibrium shape of the solder surface over the connected set of pads and examine how control of joint height is affected by the number, size and geometry of auxiliary pad configurations. We also discuss results from some preliminary experiments that we are conducting to validate our modeling results.
Highly Reliable Solderless Contact with Press-fit Technology for Power Modules
Authors: Egusa Minoru , Ishibashi Hidetoshi , Otsubo Yoshitaka , Kikuchi Masao , Kashiba Yoshihiro
Published: December 2018

Press-fit technology has been expected as a mounting technique instead of soldering in power electronics. To apply press-fit technology to power modules, the basic behavior of the contact resistance and an interface reaction of the press-fit contact are studied. Further, maintaining a stable contact force is important to maintain a low contact resistance. Factors that reduce the contact force include the displacement by the geometric tolerance of the pin and through-hole of the printed circuit board, and the thermal cycle load. We solved the problem by designing a new press-fit pin structure that provides the constricted portion for the body part of the press-fit pin, and clarified by thermal cycle test on power modules.
Implementation of a Temperature Ramp Rate Requirement and Impact on the Packaging Processes
Authors: Hamm Randy , Whitlock Daren , Eatinger Ryan , Stearns Jeremy , Ringwood Samuel
Published: December 2018

This paper addresses implementation of a heating and cooling temperature ramp rate requirement and its impact on packaging processes. A complex multi-chip module packaging design includes a printed wiring board, solder attachment of a AlSiC-9 back plate, solder attachment of a multi-room seal frame, soldered surface mount components, power die soldered directly to a heat sink, epoxy attached chip-and-wire die, a welded lid and ribbon cable. Because of complex material interactions that exist in the design, concerns arose about cracking and other thermally induced damage that might occur during temperature excursions. The assembly challenge that resulted was a product requirement to limit the heating and cooling temperature ramp rates during packaging processes. Working together, the design agency and production agency ultimately came to an agreement on what the temperature ramp rate requirement should be and how to qualify the processes and the periodic determination of compliance.

The requirement was implemented on all packaging processes that saw a heating and cooling cycle. Epoxy cure after die attach and wire bonding were modified most significantly and are specifically addressed in this paper. Solutions were implemented to minimize impact to assembly flowtime and to minimize the chance of processing errors. Temperature profiles had the ramp rates calculated then documented and qualified based on the process parameters (set point temperatures and dwell times) and the assembly machines, ovens, hot plates and tooling used. Compliance is proved through thermal profiling and calculation of ramp rate. Deviation from the set process will require approval from the design agency.
Analysis of Ultrasonic Welding of Mechanically Coupled Small Area Contacts for a Silicon Carbide Power Module
Authors: Saxena Kuldeep , Hays Aryn , Kao Ivan , Cole Zach
Published: December 2018

In this paper, the shear strength of small-area welded contacts was optimized. Using design of experiments (DoE) optimization techniques, copper power contacts with 4 mm2 feet were welded to both copper and nickel/gold-plated copper substrates where pressure, amplitude and deformation were the control factors. For the DoE, the setting combinations were chosen based on the concept of classical Screening Design. This design was best suited because it allowed an elementary exploration of interaction relationships for a wide range of factors. The pressure was varied from 1.4 to 1.8 bar, the amplitude from 90 to 100%, and the deformation from 0.06 to 0.1 mm. These limits were chosen based on prior welding experience with the equipment and similar parts. Each bond was optically inspected to confirm high-quality bonds. Using common shear techniques, over 200 bonds were sheared; strengths were recorded as the DoE dependent variable.

The initial step found that pressure was the most significant factor. Pressure and deformation were also proven to affect strength inversely to each other. Interestingly, the planarity of the contacts had no measurable effect on the welding strength. Consistent bond strengths were achieved regardless of the bonds' place within the established bond order. For both copper-to-copper and copper-to-nickel/gold-plated bonds, the optimal settings were: pressure at 1.8 bar, amplitude at 90%, and deformation of 0.1 mm, while achieving shear strengths of 40.5 kgf and 39.1 kgf, respectively. This doubled the previous benchmark weld strengths.
A New Method for Non-Destructive Characterization of Through Holes in Printed Circuit Boards
Authors: Czaplewski Sarah , Doman Joe , Kuczynski Joe
Published: December 2018

Plated through hole (PTH) quality, including plating roughness, is a critical factor in the manufacture of reliable printed circuit boards (PCBs). Currently, cross-sectioning is most commonly used to assess PTH roughness but sectioning is a destructive process and offers a limited view of the PTH. Therefore, a non-destructive casting method using a silicone elastomer was developed to evaluate PTH roughness. Castings were successfully created from PTHs with aspect ratios as high as 22:1 and the castings accurately replicated the microtopography of the plating. Laser scanning microscopy was used to quantitatively measure the surface roughness of the castings which was shown to correlate to current induced thermal cycling (CITC) coupon cycles to failure, a measurement of PTH reliability. Thus, the casting technique can be used to quickly assess PTH quality and its effect on reliability. In addition to plating roughness, it was demonstrated that the casting technique can be used to evaluate back drill quality, PTH diameter along the length of the barrel, as well as drill and desmear processes by casting non-plated through holes.
Microstructure and Mechanical Properties of Pressureless Sintered Silver Die-attach Materials
Authors: Watanabe Tomofumi , Tanaka Keisuke , Takesue Masafumi
Published: December 2018

Microstructural and mechanical properties of a pressureless sintered silver material were measured. The Microstructure of the pressureless sintered silver material had pores of less than 1 μm in size and some silver matrices sintered with nanoparticles between each other. The pressureless sintered silver material could be bonded on bare copper without applying an external pressure. After subjecting the material to a high temperature exposure test at 250 °C and for 1000 h, it showed no substantial change in microstructure and showed a constant Young's modulus of 14 GPa. The pressureless sintered silver material in this work did not show any embrittlement or increase in pore size after the high temperature exposure test, which demonstrated that the material has reliable physical and mechanical properties at temperatures up to 250 °C.
Development of High Temperature Tantalum Polymer Capacitors
Authors: Chacko Antony P. , Chen James , Stolarski Chris , MotaCaetano Cristina , Lessner Philip
Published: December 2018

This paper focuses on the development of new 150°C capable surface mount polymer tantalum capacitors and the enabling technologies. The conductivity stability of the conducting polymers at high temperatures as well as the equivalent series resistance (ESR) stability of the polymer tantalum capacitors at these temperatures were investigated in this study. Analysis of the oxygen permeation paths causing polymer oxidation and materials solutions for preventing oxygen permeation and polymer oxidation are described. The development of new cathode and protective coating material technology is presented. Their effectiveness in providing high temperature ESR stability is demonstrated by high temperature life test at 150°C of polymer capacitors.