Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Rao R. Tummala; Committee Member: C. P. Wong; Committee Member: P. M. Raj.

Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Prof. Rao R Tummala; Committee Member: Dr. Jack Moon; Committee Member: Dr. P M Raj.

Thesis (M.S.)--Rochester Institute of Technology, 2008. / Typescript. Includes bibliographical references (leaves 96-98).

Thesis (Ph. D.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

A surface pretreatment for aluminum and titanium involving the reaction of phosphonic acid (RPO(OH)2), R=butyl or vinyl for aluminum and R=vinyl for titanium, has been investigated. The durability of phosphonic acid-pretreated samples was compared with that for P2-etched (ferric sulfate-sulfuric acid) adherends. Samples were bonded with LaRC-IA adhesive in a wedge test geometry. Environmental testing consisted of static and cyclical exposure for 240 hours in three atmospheres: 1) 170°C, 2 torr; 2) -20°C; 3) 60°C, 70% relative humidity. Crack propagation arrested within 48 hours. The order of durability in static environmental tests for aluminum was vinyl phosphonic acid > P2 > butyl phosphonic acid. The durability performance was reversed for cyclic testing. The durability of specimens using P2-etched titanium was superior to that for vinyl phosphonic acid-treated titanium in all environmental tests. / Master of Science

The bonding of plastic sheeting to metal is a recent development of the surface coating industry. The product, a pre-finished material, has the strength of the base metal and exterior finish of the plastic. It is used in making radio and television cabinets, furniture, and chemical containers. In order to improve the bonding practice, it is necessary for the engineer to be well informed of the fundamental principles involved. A knowledge of the theory of bonding, the nature of the bond, and the factors affecting the bond strength would be helpful in attaining this goal. The purpose of this investigation was to study the factors affecting the bond strength between polyvinyl chloride sheeting and metal. The metals used in this investigation were aluminum, brass, copper, nickel, low carbon steel, and stainless steel. The plastic sheeting was bonded to the metal by means of synthetic adhesive. Five different commercial adhesives were used. These were vinyl chloride-acetate resin, VYNW, modified vinyl chloride-acetate resin, VMCH, vinyl acetate resin, A-70, vinyl alcohol-acetate resin, T-24-9, and vinyl alcohol-acetate resin, MA-28-18. The specimens of metal were treated as follows. Three sets of specimens were prepared. The first set was degreased with solvent only, the second one was polished and degreased, and the third one was degreased and etched. Semi-rigid polyvinyl chloride sheeting was bonded to the metal at a temperature of 70°, 150°, 250°, and 350°F under a pressure of 200 pounds per square inch. A series of the bonded specimens was stretched to 10, 20, and 30 percent elongation. A series of steel-steel laminates was prepared. They were bonded by different adhesives at 250°F under 200 pounds per square inch. The specimens of this series were tested for shear strength. The effect of surface conditions, of bonding temperatures, of nature of metals, of types of adhesives, and of amount of plasticizer in the adhesive upon the bond strength between polyvinyl chloride sheet and metal was determined and the following conclusions were reached: 1. The bond strength was affected by surface conditions. Etched specimens had higher bond strength than polished ones except low carbon steel. 2. The bonding temperature had no definite influence on the bond strengths of aluminum, nickel, low carbon steel, and stainless steel laminates. 3. The bond strengths of brass and copper laminates increased with the bonding temperature. 4. The average bond strengths of polished specimens of low carbon steel, aluminum, stainless steel, nickel, copper, and brass were 19.6, 15.5, 14.2, 8.5, 5.5, and 2.5 pounds per inch respectively. The strengths of these metal laminates followed the order of these metals in the galvanic series except aluminum. 5. The adhesion between adhesive and metal varied directly with the polarity of the adhesive. 6. The bond strength was also affected by the amount of plasticizer in the adhesive. When the laminates were subjected to stretching, the rate of decrease in strength was inversely proportional to the amount of plasticizer in the adhesive. / Master of Science

This Thesis describes the synthesis and characterisation of new alkaline earth metal and aluminium gallyl complexes. Experimental studies were performed to investigate their structure. The reactivity of these species was also studied. <b>Chapter 1</b> introduces metal-metal bonded complexes containing alkaline earth metals and aluminium and the use of gallium(I) analogues of N-heterocyclic carbenes in the synthesis of heterobimetallic complexes of gallium. <b>Chapter 2</b> describes the synthesis and reactivity of alkaline earth gallyl complexes supported by beta-diketiminate ligands. <b>Chapter 3</b> presents the synthesis and reactivity of alkaline earth gallyl complexes supported by the carbazolide ligand CzOx. <b>Chapter 4</b> describes synthesis of aluminium-gallium bonded complexes supported by amidinate and b-diketiminate ligands and the attempted study of their reactivity. <b>Chapter 5</b> presents full experimental procedures and characterising data for the new complexes reported.

Microelectronic interconnections require advanced joining techniques. Direct metal bonding methods, which include thercomsonic and thermocompression bonding, offer remarkable advantages over soldering and adhesives joining. These processes are reviewed in this paper. The progress made in this area is outlined. Some work concerned with the bonding modeling is also presented. This model is based on the joint interface mechanics resulting from compression. Both bump and substrate deformation are taken into account. The improved understanding of the relationship between the deformation and bonding formation may provide more accurate joint evaluation criterion. / Singapore-MIT Alliance (SMA)

"More Than Moore's Law" is the driving principle for the electronic packaging industry. This principle focuses on system integration instead of transistor density in order to achieve faster, thinner, and smarter electronic devices at a low cost. A core area of electronics packaging is interconnection technology, which enables ultra-miniaturization and high functional density. Solder bump technology is one of the original, and most common interconnection methods for flip chips. With growing demand for finer pitch and higher number of I/Os, solder bumps have been forced to smaller dimensions and therefore, are subjected to higher current densities. However, the technology is now reaching its fundamental limitations in terms of pitch, processability, and current-handling due to electromigration. Electromigration in solder bumps is one of the major causes of device failures. It is accelerated by many factors, one of which is current crowding. Current crowding is the non-uniform distribution of current at the interface of the solder bump and under-bump metallurgy, resulting in an increase in local current density and temperature. These factors, along with the formation of intermetallic compounds, can lead to voiding and ultimately failure. Electromigration in solder bumps has prevented pitch-scaling below 180-210 microns, producing a shift in the packaging industry to other interconnection approaches, specifically copper pillars with solder. This research aims to explore the electromigration resistance of an adhesive-based copper-to-copper (Cu-Cu) interconnection method without solder, which is thermo-compression bonded at a low temperature of 180C. While solder bumps are more susceptible to electromigration, Cu is capable of handling two orders of magnitude higher current density. This makes it an ideal candidate for next generation flip chip interconnections. Using finite element analysis, the current crowding and joule heating effects were evaluated for a 30 micron diameter Cu-Cu interconnection in comparison with two existing flip chip interconnection techniques, Cu pillar with solder and Pb-free solder. A test vehicle (TV) was fabricated for experimental analysis with 760 bumps arranged in an area-array format with a bump diameter of 30 micron. Thermo-mechanical reliability of the test vehicle was validated under thermal cycling from -55C to 125C. The Cu-Cu interconnections were then subjected to high current and temperature stress from 1E4 to 1E6 amps per square centimeter at a temperature of 130C. The results establish the high thermo-mechanical reliability and high electromigration resistance of the proposed Cu-Cu interconnection technology.

published_or_final_version / abstract / toc / Chemistry / Doctoral / Doctor of Philosophy