Organizational Unit:

School of Materials Science and Engineering

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https://hdl.handle.net/1853/70762

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Organizational Unit

College of Engineering

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https://finding-aids.library.gatech.edu/agents/corporate_entities/1126

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Publication Search Results

Now showing 1 - 10 of 18

High dielectric constant polymer nanocomposites for embedded capacitor applications

(Georgia Institute of Technology, 2008-09-17) Lu, Jiongxin

Driven by ever growing demands of miniaturization, increased functionality, high performance and low cost for microelectronic products and packaging, embedded passives will be one of the key emerging techniques for realizing the system integration which offer various advantages over traditional discrete components. Novel materials for embedded capacitor applications are in great demand, for which a high dielectric constant (k), low dielectric loss and process compatibility with printed circuit boards are the most important prerequisites. To date, no available material satisfies all these prerequisites and research is needed to develop materials for embedded capacitor applications. Conductive filler/polymer composites are likely candidate material because they show a dramatic increase in their dielectric constant close to the percolation threshold. One of the major hurdles for this type of high-k composites is the high dielectric loss inherent in these systems. In this research, material and process innovations were explored to design and develop conductive filler/polymer nanocomposites based on nanoparticles with controlled parameters to fulfill the balance between sufficiently high-k and low dielectric loss, which satisfied the requirements for embedded decoupling capacitor applications. This work involved the synthesis of the metal nanoparticles with different parameters including size, size distribution, aggregation and surface properties, and an investigation on how these varied parameters impact the dielectric properties of the high-k nanocomposites incorporated with these metal nanoparticles. The dielectric behaviors of the nanocomposites were studied systematically over a range of frequencies to determine the dependence of dielectric constant, dielectric loss tangent and dielectric strength on these parameters.
Flexible magnetic composite for antenna applications in radio frequency identification (RFID)

(Georgia Institute of Technology, 2008-03-17) Martin, Lara Jean

This work includes formulation of mechanically flexible magnetic composites and application to a quarter-wavelength microstrip patch antenna benchmarking structure operating in the lower UHF spectrum (~300-500 MHz) to investigate capability for miniaturization. A key challenge is to introduce sufficiently low magnetic loss for successful application. Particles of NiZn ferrite and BaCo ferrite, also known as Co2Z, were characterized. Flexible magnetic composites comprised of 40 vol% NiZn ferrite or BaCo ferrite particles in a silicone matrix were formulated. Effects of treating the particles with silane in the formulation process were not detectable, but larger particle size showed to increase complex permittivity and complex permeability. By comparing complex permittivity and complex permeability of the composites, BaCo ferrite was selected for the antenna application. Antennas on the developed magnetic composite and pure silicone substrates were electromagnetically modeled in a full-wave FEM EM solver. A prototype of the antenna on the magnetic composite was fabricated. Good agreement between the simulated and measured results was found. Comparison of the antennas on the magnetic composite versus the pure silicone substrate showed miniaturization capability of 2.4X and performance differences of increased bandwidth, reduced Q, and reduced gain. A key finding of this study is that a small amount of permeability (relative permeability ~2.5) can provide relatively substantial capability for miniaturization, while sufficiently low magnetic loss can be introduced for successful application at the targeted operating frequency. The magnetic composite showed the capability to fulfill this balance and to be a feasible option for RFID applications in the lower UHF spectrum.
High performance electrically conductive adhesives (ecas) for leadfree interconnects

(Georgia Institute of Technology, 2007-11-02) Li, Yi

Electrically conductive adhesives (ECAs) are one of the lead-free interconnect materials with the advantages of environmental friendliness, mild processing conditions, fewer processing steps, low stress on the substrates, and fine pitch interconnect capability. However, some challenging issues still exist for the currently available ECAs, including lower electrical conductivity, conductivity fatigue in reliability tests, limited current-carrying capability, poor impact strength, etc. The interfacial properties is one of the major considerations when resolving these challenges and developing high performance conductive adhesives. Surface functionalization and interface modification are the major approaches used in this thesis. Fundamental understanding and analysis of the interaction between various types of interface modifiers and ECA materials and substrates are the key for the development of high performance ECA for lead-free interconnects. The results of this thesis provide the guideline for the enhancement of interfacial properties of metal-metal and metal-polymer interactions. Systematic investigation of various types of ECAs contributes to a better understanding of materials requirements for different applications, such as surface mount technology (SMT), flip chip applications, flat panel display modules with high resolution, etc. Improvement of the electrical, thermal and reliability of different ECAs make them a potentially ideal candidate for high power and fine pitch microelectronics packaging option.
Dielectric Nanocomposites for High Performance Embedded Capacitors in Organic Printed Circuit Boards

(Georgia Institute of Technology, 2006-06-23) Xu, Jianwen

Conventionally discrete passive components like capacitors, resistors, and inductors are surface-mounted on top of the printed circuit boards (PCBs). To match the ever increasing demands of miniaturization, cost reduction, and high performance in microelectronic industry, a promising approach is to integrate passive components into the board during PCB manufacture. Because they are embedded inside multilayer PCBs, such components are called embedded passives. This work focuses on the materials design, development and processing of polymer-based dielectric nanocomposites for embedded capacitor applications. The methodology of this approach is to combine the advantages of the polymer and the filler to satisfy the electric, dielectric, mechanical, fabrication, and reliability requirements for embedded capacitors. Restrained by poor adhesion and poor thermal stress reliability at high filler loadings, currently polymer-ceramic composites can only achieve a dielectric constant of less than 50. In order to increase the dielectric constant to above 50, effects of high-k polymer matrix, bimodal fillers, and dispersing agent are systematically investigated. Surface functionalization of nanofiller particles and modification of epoxy matrix with a secondary rubberized epoxy to form sea-island structure are proposed to enhance the dielectric constant, adhesion and high-temperature thermal stress reliability of high-k composites. To obtain photodefinable high-k composites, fundamental understanding of the photopolymerization of the novel epoxy-ceramic composite photoresist is addressed. While the properties of high-k composites largely depend on the polymer matrix, the fillers can also drastically affect the material properties. Carbon black- and carbon nanotubes-filled ultrahigh-k polymer composites are investigated as the candidate materials for embedded capacitors. Dielectric composites based on percolation typically show a high dielectric constant, and a high dielectric loss which is not desirable for high frequency applications. To achieve a reproducible low-loss percolative composite, a novel low-cost core-shell particle filled high-k percolative composite is developed. The nanoscale insulating shells allow the electrons in the metallic core to tunnel through it, and thereby the composites exhibit a high dielectric constant as a percolation system; on the other hand, the insulating oxide layer restricts the electron transfer between filler particles, thus leading to a low loss as in a polymer-ceramic system.
Study of thermally reworkable epoxy materials and thermal conductivity enhancement using carbon fiber for electronics packaging

(Georgia Institute of Technology, 2003-12-01) Li, Haiying
Study on the curing process of no-flow and wafer level underfill for flip-chip applications

(Georgia Institute of Technology, 2003-12-01) Zhang, Zhuqing
Development of a polymer-metal nanocomposite dielectric by in situ reduction for embedded capacitor application

(Georgia Institute of Technology, 2003-12-01) Pothukuchi, Suresh V.
Evaluation of low stress dielectrics for board applications

(Georgia Institute of Technology, 2002-12) Brownlee, Kellee Renee
Study on adhesion of underfill materials for flip chip packaging

(Georgia Institute of Technology, 2002-05) Luo, Shijian
Study of high K polymers for integral capacitor applications

(Georgia Institute of Technology, 2001-12) Yue, Jireh Jon-Kai