LCP has the properties of both polymers and liquid crystals. It, thus, can be bonded to silicon, metal, and glass and used as flexible circuit board. In lead-free soldering, fundamental soldering principle is presented. To eliminate the use of fluxes, oxidation-free fluxless soldering was developed.
Two fluxless processes are reported. Resulting joints are Sn with a little Ag. High bonding quality is achieved without using any flux. In solid-state bonding technology, the bonding principle and a new quantum bonding theory are presented. Processes of bonding Cu with Ag layer to Cu substrates is reported, including shear test results and failure mode analyses. Nothing else is used. Compared to solder-based flip-chip technique, our technology has 12 advantages.
Compared to Cu pillar technique, our technology has much wider process window. It includes the development processes, pull strength results, and failure mode analyses. Transistor scaling, shrinking the critical dimensions of the transistor, has led to continuous improvements in system performance and cost. Higher density of the transistors and larger chip size has also led to new challenges for chip-to-substrate connections. The pace of change in packaging and chip-to-substrate connections has accelerated because off-chip issues are increasingly a limiting factor in product cost and performance.
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This chapter examines various techniques and structures that have been designed to address these challenges. The mechanical compliance and electrical performance modeling of the interconnect structures is important in determining the geometry, materials, and processing necessary for an application. Mechanically compliant structures based on traditional solder-bonded connections can drastically improve thermomechanical reliability but may compromise electrical performance.
Additional structures improve upon the compliance of the solder ball by capping a pillar structure with solder, but still require the reliable protection of underfill. More high performance and long-term improvements to satisfy both mechanical and electrical needs such as interconnects composed entirely of copper are also discussed. Finally, the future needs projected by the ITRS for ultra-high off-chip frequency and thermal management are addressed with respect to chip-to-substrate interconnects.
Wire bonding is by far the most dominate form of first-level chip connection. This chapter focuses on the basic techniques of wire bonding along with the materials, structures, and methods which enable its implementation. The emphasis is placed on ball bonding thermosonic bonding using both copper and gold bonding wire. Discussion of bonding machine parameters and various wire bond test methods are presented.
Basic wire bond experimental studies are presented in some detail for two major purposes: 1 to highlight some of the key results of the experiments, and 2 to serve as a model for other researchers to either emulate or use as a starting point in their own wire bond investigations.
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Materials are fundamental to the reliability of wire bonding and where possible the author explores the major materials and material systems in some detail. Overall the chapter provides a frame work for the basic understanding of wire bonding for people new to the field as well as enough detailed information for the advanced practitioner.
Driven by RoHS regulation, the world has been migrating toward lead-free soldering since late s. In this chapter, the main stream lead-free soldering practice was presented, and the properties of lead-free solder materials and soldering joints, including intermetallic compounds and microstructure evolution, were exemplified and discussed. Furthermore, the major categories of reliability of solder joints, including temperature cycling, fragility, electromigration, and tin whisker, were described and the mechanism was elucidated.
Lastly, the trends and status of novel lead-free solder alloys, including low temperature, low cost and high reliability, and high temperature alloys were briefly introduced and reviewed. Thin die fabrication is an essential part of wafer processes in 3D IC, interposer, and fan-in and fan-out wafer level packaging technologies. A review on the available process technologies including temporary bonding, de-bonding, wafer thinning, thin wafer handling, thin wafer backside processes, and die singulation are discussed and summarized in this chapter.
The fabricated thin dies are integrated and assembled using wafer level system integration WLSI processes.
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Future trends of organic substrate development are covered in this chapter as well. In order to enhance the reliability of a flip-chip on organic board package, underfill is usually used to redistribute the thermo-mechanical stress created by the Coefficient of Thermal Expansion CTE mismatch between the silicon chip and organic substrate. However, the conventional underfill relies on the capillary flow of the underfill material and has many disadvantages.
In order to overcome these disadvantages, many variations have been invented to improve the flip-chip underfill process. This chapter reviews the recent advances in the material design, process development, and reliability issues of flip-chip underfill, especially in no-flow underfill, molded underfill, and wafer-level underfill.
The relationship between the materials, process, and reliability in these packages is discussed. EMCs Epoxy molding compounds have been used extensively as an encapsulation and protection material for semiconductor packages. As semiconductor packages trend toward thinner, miniaturized, more function, and higher density, new requirements for EMCs are emerging.
This chapter provides an overview of the most recent development on various aspects of EMC technology including advanced material development, molding process, and approaches to address different kinds of advanced packages. Conductive adhesives consist of conductive particles and polymeric matrix, and can provide both electrical and mechanical connections.
Much advance on conductive adhesive technology has been made over the years. This chapter provides a comprehensive overview on the basic aspects, key applications in electronic packaging, and latest advances of both anisotropically conductive adhesives ACAs and isotropically conductive adhesives ICAs. This chapter outlines the strong correlation between developments in electronic packaging technologies and required properties of die attach materials. An overview of die attach materials is summarized with the trends in the market.
Die attach paste, adhesive tape for a lead on chip LOC , die attach film, and the prospects of advanced die attach film are described in each section. The technical requirements of the die attach materials, which include high purity, fast curing, low stress, high package crack resistance, and multi-chip packaging are discussed. Die attach films have become the main stream of die attach materials owing to their excellent properties and reliability.
The effects of adhesive properties such as peel strength and water absorption to improve package crack resistance are reported in detail. The development of die attach films with micro-phase separation structure for multi-layered packaging process is reviewed. Evaluation of die attach materials for next generation packages is also introduced.
Increasing electronic device performance has historically been accompanied by increasing power and increasing on-chip power density both of which present a cooling challenge. Thermal interface material TIM plays a key role in reducing the package thermal resistance and the thermal resistance between the electronic device and the external cooling components. This chapter reviews the progress made in the TIM development in the past 5 years. Rheology-based modeling and design is discussed for the widely used polymeric TIMs.
The recently emerging technology of nanoparticles and nanotubes is also discussed for TIM applications. This chapter also includes TIM testing methodology and concludes with suggestion for the future TIM development directions. Emerging portable smart devices with more functionality demands high-performance, smaller, lighter, thinner, and cheaper electronic components. Content Protection. Flag as inappropriate. It syncs automatically with your account and allows you to read online or offline wherever you are.
Please follow the detailed Help center instructions to transfer the files to supported eReaders. More related to materials science. See more. Book This volume provides a comprehensive reference for graduate students and professionals in both academia and industry on the fundamentals, processing details, and applications of 3D microelectronic packaging, an industry trend for future microelectronic packages. Chapters written by experts cover the most recent research results and industry progress in the following areas: TSV, die processing, micro bumps, direct bonding, thermal compression bonding, advanced materials, heat dissipation, thermal management, thermal mechanical modeling, quality, reliability, fault isolation, and failure analysis of 3D microelectronic packages.
Numerous images, tables, and didactic schematics are included throughout. This essential volume equips readers with an in-depth understanding of all aspects of 3D packaging, including packaging architecture, processing, thermal mechanical and moisture related reliability concerns, common failures, developing areas, and future challenges, providing insights into key areas for future research and development. Nanoporous Metals for Advanced Energy Technologies. Yi Ding.
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This book covers the state-of-the-art research in nanoporous metals for potential applications in advanced energy fields, including proton exchange membrane fuel cells, Li batteries Li ion, Li-S, and Li-O2 , and supercapacitors. The related structural design and performance of nanoporous metals as well as possible mechanisms and challenges are fully addressed. The formation mechanisms of nanoporous metals during dealloying, the microstructures of nanoporous metals and characterization methods, as well as miscrostructural regulation of nanoporous metals through alloy design of precursors and surface diffusion control are also covered in detail.
Copper Interconnect Technology. Tapan Gupta. Since overall circuit performance has depended primarily on transistor properties, previous efforts to enhance circuit and system speed were focused on transistors as well. During the last decade, however, the parasitic resistance, capacitance, and inductance associated with interconnections began to influence circuit performance and will be the primary factors in the evolution of nanoscale ULSI technology. Because metallic conductivity and resistance to electromigration of bulk copper Cu are better than aluminum, use of copper and low-k materials is now prevalent in the international microelectronics industry.
As the feature size of the Cu-lines forming interconnects is scaled, resistivity of the lines increases.
At the same time electromigration and stress-induced voids due to increased current density become significant reliability issues. In this book, a leader in the field describes advanced laser systems with lower radiation wavelengths, photolithography materials, and mathematical modeling approaches to address the challenges of Cu-interconnect technology. Dimitris Tsoukalas. The conference provided an open forum for the presentation of the latest results and trends in process and device simulation. The trend towards shrinking device dimensions and increasing complexity in process technology demands the continuous development of advanced models describing basic physical phenomena involved.
New simulation tools are developed to complete the hierarchy in the Technology Computer Aided Design simulation chain between microscopic and macroscopic approaches. The conference program featured 8 invited papers, 60 papers for oral presentation and 34 papers for poster presentation, selected from a total of abstracts from 30 countries around the world. These papers disclose new and interesting concepts for simulating processes and devices.