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 16

Epoxy/triazine based high performance molding compound for next generation power electronics packaging

(Georgia Institute of Technology, 2019-07-26) Li, Jiaxiong

The power electronics industry has been actively seeking encapsulant materials that can serve in harsher environments. For example, with the power semiconductors leading into SiC era, the higher operation temperature (250 ºC) have proposed great challenges on the packaging materials especially on epoxy molding compound (EMC) technologies, since the temperature exceeds the stability limit of typical epoxy (EP) chemistry. In this thesis, EP/triazine system was selected to develop high temperature stable resin system that can meet the temperature requirement of next generation power electronics packaging. In the first part of the thesis, different approaches were discussed to enhance the high temperature performance of a previously studied cyanate ester (CE)/ biphenyl EP blend which is impaired by the hydrolysis degradation of remaining cyanate groups. Firstly, the effects of different metal catalyst on the CE properties were discussed. Secondly, a triazine containing molecule triglycidyl isocyanurate (TGIC) was employed to increase the triazine content without increasing CE feed ratio to circumstance problem of unreacted cyanate groups. Finally, the high heat resistant novolac type CE was employed to form the NCE/EP blend, and their blends with different feed ratio were systematically evaluated. In the second part, a detailed characterization of a high heat resistant CE/novolac type EP blends and the investigation on their degradation under long-term high temperature storage were summarized. The effects of the CE concentration on the thermomechanical properties of the copolymer were explored, where a tradeoff behavior between the triazine content and crosslink density was accounted for the property change. In addition, the distinguished thermal degradation mechanisms in copolymer with different compositions were identified and illustrated. The knowledge obtained in this work can serve as a reference in the future to formulate EP/triazine based resin system for high temperature applications.
Encapsulation and design of scalable packaging materials for thin film perovskite solar cell applications

(Georgia Institute of Technology, 2019-04-25) Hah, Jinho

There have been many attempts to improve the stability of the environmentally-sensitive perovskite solar cells (PSCs) from adverse environments. The next generation encapsulation method should be compatible with roll-to-roll (R2R) processing, which can manufacture thin-film PSC modules at large scale and make solar electricity economically competitive with conventional electricity generation. This work investigates the interface chemistry between the polymer backsheet and the polymer encapsulants to understand the moisture, thermal, and UV stability of the packaging materials for PSCs. First, surface modification on the commercially available PET backsheets was done using various types of silane-based coupling agents, and their adhesion profiles were studied upon damp-heat exposure on these samples. Second, thorough XPS analysis was conducted on the delaminated PET surface from the PET/EVA/PET encapsulation architecture upon the UV, thermal, and moisture aging to understand the degradation mechanism at the interface. Moreover, this work also includes encapsulant design by combining the polymer blends to improve the mechanical and chemical bulk properties of a PV encapsulant. In short, this work serves to investigate on the encapsulation methods to improve the reliability and lifetime of PSCs.
Study on epoxy based composites for high temperature molding compounds

(Georgia Institute of Technology, 2018-07-19) Wu, Fan

Epoxy molding compound (EMC) is one of the most widely used encapsulation materials for electronic packaging. To provide substantial protection for the electronic packages, EMCs are frequently required to work at elevated temperature, especially when high power and high density devices are developing rapidly and more heat is generated during operation. This thesis discussed the study on epoxy based composites for high temperature molding compounds by investigating two components most important in EMC system, namely the polymer resin and the filler system. In order to increase the glass transition temperature (Tg) and thermal stability of epoxy resin, cyanate ester was incorporated into the polymer matrix. The copolymer network formed by epoxy and cyanate ester (CE/EP) exhibited excellent thermal stability and high Tg above 270 ℃ because of the thermally stable s-triazine structures formed by cyanate ester trimerization. However, cyanate ester was affected by the hydrolysis reaction and too much cyanate ester in the system led to blistering and Tg drops in high temperature and high humidity tests. The cyanate ester amount in this copolymer was optimized to be 33-50 %. Polyimide was incorporated into CE/EP system as an additive (CE/EP-PI) to further improve the thermal stability of this epoxy-based resin. Aromatic polyimide exhibited good compatibility with CE/EP for their structural similarity. Improvements in Tg, storage modulus, fracture toughness and long term high temperature performance were observed at 5-10 % polyimide loading. At high polyimide loading level (> 10 %), a secondary phase emerged which deteriorated the resin properties such as storage modulus. The second part of this thesis investigated a modified filler system with surface coated silicon carbide (SiC) for thermal conductivity enhancement. In this part, SiC with high thermal conductivity was adopted as a replacement for conventional silica fillers. After surface treatment by silane coupling agent (SiC-GPTMS) and reactive silicon rubber (SiC-A15), modified SiC increased the thermal conductivity of the composites from 0.11 W/mK to 0.28 W/mK at 30 % filler loading.
Highly conductive stretchable electrically conductive composites for electronic and radio frequency devices

(Georgia Institute of Technology, 2011-07-05) Agar, Joshua Carl

The electronics industry is shifting its emphasis from reducing transistor size and operational frequency to increasing device integration, reducing form factor and increasing the interface of electronics with their surroundings. This new emphasis has created increased demands on the electronic package. To accomplish the goals to increase device integration and interfaces will undoubtedly require new materials with increased functionality both electrically and mechanically. This thesis focuses on developing new interconnect and printable conductive materials capable of providing power, ground and signal transmission with enhanced electrical performance and mechanical flexibility and robustness. More specifically, we develop: 1.) A new understanding of the conduction mechanism in electrically conductive composites (ECC). 2.) Develop highly conductive stretchable silicone ECC (S-ECC) via in-situ nanoparticle formation and sintering. 3.) Fabricate and test stretchable radio frequency devices based on S-ECC. 4.) Develop techniques and processes necessary to fabricate a stretchable package for stretchable electronic and radio frequency devices. In this thesis we provide convincing evidence that conduction in ECC occurs predominantly through secondary charge transport mechanism (tunneling, hopping). Furthermore, we develop a stretchable silicone-based ECC which, through the incorporation of a special additive, can form and sinter nanoparticles on the surface of the metallic conductive fillers. This sintering process decreases the contact resistance and enhances conductivity of the composite. The conductive composite developed has the best reported conductivity, stretchability and reliability. Using this S-ECC we fabricate a stretchable microstrip line with good performance up to 6 GHz and a stretchable antenna with good return loss and bandwidth. The work presented provides a foundation to create high performance stretchable electronic packages and radio frequency devices for curvilinear spaces. Future development of these technologies will enable the fabrication of ultra-low stress large area interconnects, reconfigurable antennas and other electronic and RF devices where the ability to flex and stretch provides additional functionality impossible using conventional rigid electronics.
Increase the packing density of vertically aligned carbon nanotube array for the application of thermal interface materials

(Georgia Institute of Technology, 2011-03-23) Gu, Wentian

To fulfill the potential of carbon nanotube (CNT) as thermal interface material (TIM), the packing density of CNT array needs improvement. In this work, two potential ways to increase the packing density of CNT array are tested. They are liquid precursor(LP)CVD and cycled catalyst deposition method. Although LP-CVD turned out to be no help for packing density increase, it is proved to enhance the CNT growth rate. The packing density of CNT array indeed increases with the cycle number. The thermal conductivity of the CNT array increases with the packing density. This work is believed to be a step closer to the real life application of CNT in electronic packaging industry.
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 of high K polymers for integral capacitor applications

(Georgia Institute of Technology, 2001-12) Yue, Jireh Jon-Kai
No-flow underfill materials for environment sensitive flip-chip process

(Georgia Institute of Technology, 2001-08) Zhang, Zhuqing
Study of polyarylene ether and its application in isotropically conductive adhesive

(Georgia Institute of Technology, 2001-08) Liong, Silvia