Conventional solder balls used in microelectronic packaging suffer from thermo- mechanical damage due to difference in coefficient of thermal expansion between the die and the substrate or the substrate and the board. Compliant interconnects are replacements for solder balls which accommodate this differential displacement by mechanically decoupling the die from the substrate or the substrate from the board and aim to improve overall reliability and life of the microelectronic component. Research is being conducted to develop compliant interconnect structures which offer good mechanical compliance without adversely affecting electrical performance, thus obtaining good thermo-mechanical reliability. However, little information is available regarding the behavior of compliant interconnects under shock and impact loads. The objective of this thesis is to study the response of a proposed multi-path compliant interconnect structure when subjected to shock and impact loading. As part of this work, scaled-up substrate-compliant interconnect-die assemblies will be fabricated through stereolithography techniques. These scaled-up prototypes will be subjected to experimental drop testing. Accelerometers will be placed on the board, and strain gauges will be attached to the board and the die at various locations. The samples will be dropped from different heights to different shock levels in the components, according to Joint Electron Devices Engineering Council (JEDEC) standards. In parallel to such experiments with compliant interconnects, similar experiments with scaled-up solder bump interconnects will also be conducted. The strain and acceleration response of the compliant interconnect assemblies will be compared against the results from solder bump interconnects. Simulations will also be carried out to mimic the experimental conditions and to gain a better understanding of the overall response of the compliant interconnects under shock and impact loading. The findings from this study will be helpful for improving the reliability of compliant interconnects under dynamic mechanical loading.

Ever growing demands for portability and functionality have always governed the electronic technology innovations. IC downscaling with Moore s law at IC level and system miniaturization with System-On-Package (SOP) paradigm at system level, have resulted and will continue to result in ultraminiaturized systems with unprecedented functionality at reduced cost. However, system miniaturization poses several electrical and thermal challenges that demand innovative solutions including advanced materials, bonding and assembly techniques. Heterogeneous material and device integration for thermal structures and IC assembly are limited by the bonding technology and the electrical and thermal impedance of the bonding interfaces. Solder - based bonding technology that is prevalent today is a major limitation to future systems. The trend towards miniaturized systems is expected to drive downscaling of IC I/O pad pitches from 40µm to 1- 5µm in future. Solder technology imposes several pitch, processability and cost restrictions at such fine pitches. Furthermore, according to International Technology Roadmap for Semiconductors (ITRS-2006), the supply current in high performance microprocessors is expected to increase to 220 A by 2012. At such supply current, the current density will exceed the maximum allowable current density of solders. The intrinsic delay and electromigration in solders are other daunting issues that become critical at nanometer sized technology nodes. In addition, formation of intermetallics is also a bottleneck that poses significant mechanical issues. Similarly, thermal power dissipation is growing to unprecedented high with a projected power of 198 W by 2008 (ITRS 2006). Present thermal interfaces are not adequate for such high heat dissipation. Recently, copper based thin film bonding has become a promising approach to address the abovementioned challenges. However, copper-copper direct bonding without using solders has not been studied thoroughly. Typically, bonding is carried out at 400oC for 30 min followed by annealing for 30 min. High thermal budget in such process makes it less attractive for integrated systems because of the associated process incompatibilities. Hence, there is a need to develop a novel low temperature copper to copper bonding process. In the present study, nanomaterials - based copper-to-copper bonding is explored and developed as an alternative to solder-based bonding. To demonstrate fine pitch bonding, the patterning of these nanoparticles is crucial. Therefore, two novel self-patterning techniques based on: 1.) Selective wetting and 2.) Selective nanoparticle deposition, are developed to address this challenge. Nanoparticle active layer facilitates diffusion and, thus, a reliable bond can be achieved using less thermal budget. Quantitative characterization of the bonding revealed good metallurgical bonding with very high bond strength. This has been confirmed by several morphological and structural characterizations. A 30-micron pitch IC assembly test vehicle is used to demonstrate fine pitch patternability and bonding. In conclusion, novel nanoparticle synthesis and patterning techniques were developed and demonstrated for low-impedance and low-cost electrical and thermal interfaces.

Ever growing demands for portability and functionality have always governed the electronic technology innovations. IC downscaling with Moore s law and system miniaturization with System-On-Package (SOP) paradigm has resulted and will continue to result in ultraminiaturized systems with unprecedented functionality at reduced cost. The trend towards 3D silicon system integration is expected to downscale IC I/O pad pitches from 40µm to 1- 5 µm in future. Device- to- system board interconnections are typically accomplished today with either wire bonding or solders. Both of these are incremental and run into either electrical or mechanical barriers as they are extended to higher density of interconnections. Alternate interconnection approaches such as compliant interconnects typically require lengthy connections and are therefore limited in terms of electrical properties, although expected to meet the mechanical requirements. As supply currents will increase upto 220 A by 2012, the current density will exceed the maximum allowable current density of solders. The intrinsic delay and electromigration in solders are other daunting issues that become critical at nanometer size technology nodes. In addition, formation of intermetallics is also a bottleneck that poses significant mechanical issues. Recently, many research groups have investigated various techniques for copper-copper direct bonding. Typically, bonding is carried out at 400oC for 30 min followed by annealing for 30 min. High thermal budget in such process makes it less attractive for integrated systems because of the associated process incompatibilities. In the present study, copper-copper bonding at ultra fine-pitch using advanced nano-conductive and non-conductive adhesives is evaluated. The proposed copper-copper based interconnects using advanced conductive and non-conductive adhesives will be a new fundamental and comprehensive paradigm to solve all the four barriers: 1) I/O pitch 2) Electrical performance 3) Reliability and 4) Cost. This thesis investigates the mechanical integrity and reliability of copper-copper bonding using advanced adhesives through test vehicle fabrication and reliability testing. Test vehicles were fabricated using low cost electro-deposition techniques and assembled onto glass carrier. Experimental results show that proposed copper-copper bonding using advanced adhesives could potentially meet all the system performance requirements for the emerging micro/nano-systems.

The current trend of ever larger clusters and data centers has coincided with a dramatic increase in the cost and power of these installations. While many efficiency improvements have focused on processor power and cooling costs, reducing the cost and power consumption of high-performance memory has mostly been overlooked. This thesis proposes a new address translation model called Dynamic Partitioned Global Address Space (DPGAS) that extends the ideas of NUMA and software-based approaches to create a high-performance hardware model that can be used to reduce the overall cost and power of memory in larger server installations. A memory model and hardware implementation of DPGAS is developed, and simulations of memory-intensive workloads are used to show potential cost and power reductions when DPGAS is integrated into a server environment.

The goal of this research was to develop new experimental techniques to quantitatively study the interfacial fracture of micro-contact thin film interconnects used in microelectronic applications under monotonic and cyclic loadings. The micro-contact spring is a new technology that is based on physical vapor deposited thin film cantilevers with a purposely-imposed stress gradient through the thickness of the film. These "springs" have the promise of being the solution to address near-term wafer level probing and long-term high-density chip-to-next level microelectronic packaging challenges, as outlined by the International Technology Roadmap for Semiconductors. The success of this technology is, in part, dependent on the ability to understand the failure mechanism under monotonic and cyclic loadings. This research proposes two experimental methods to understand the interfacial fracture under such monotonic and fatigue loading conditions. To understand interfacial fracture under monotonic loading, a fixtureless superlayer-based delamination test has been developed. Using stress-engineered Cr layer and a release layer with varying width, this test can be used to measure interfacial fracture toughness under a wide range of mode mixity. This test uses common IC fabrication techniques and overcomes the shortcomings of available methods. The developed test has been used to measure the interfacial fracture toughness for Ti/Si interface. It was found that for low mode mixity Ti/Si thin film interfaces, the fracture toughness approaches the work of adhesion which is essentially the Ti-Si bond energy for a given bond density. In addition to the monotonic decohesion test, a fixtureless fatigue test is developed to investigate the interfacial crack propagation. Using a ferromagnetic material deposited on the micro-contact spring, this test employs an external magnetic field to be able to drive the interfacial crack. Fatigue crack growth can be monitored by E-beam lithography patterned metal traces that are 10 to 40nm wide and 1 to a few µm in spacing. The crack initiation and propagation can be monitored through electrical resistance measurement. In the conducted experiments, it is seen that the interfacial delamination does not occur under fatigue loading, and that the micro-contact springs are robust against interfacial fracture for probing and packaging applications.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Systems Science and Industrial Engineering, Thomas J. Watson School of Engineering and Applied Science, 2008. / Includes bibliographical references.

Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2005. / Madhavan Swaminathan, Committee Chair ; Sung Kyu Lim, Committee Member ; Abhijit Chatterjee, Committee Member ; David C. Keezer, Committee Member ; C. P. Wong, Committee Member. Vita. Includes bibliographical references.

Time Average Fourier Telescopy (TAFT) has been proposed as a means for obtaining high-resolution, diffraction-limited images over large distances through ground-level horizontal-path atmospheric turbulence. Image data is collected in the spatial-frequency, or Fourier, domain by means of Fourier Telescopy; an inverse two dimensional Fourier transform yields the actual image. TAFT requires active illumination of the distant object by moving interference fringe patterns. Light reflected from the object is collected by a “light-bucket” detector, and the resulting electrical signal is digitized and subjected to a series of signal processing operations, including an all-critical averaging of the amplitude and phase of a number of narrow-band signals. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

The objective of this dissertation is to classify the opportunities, advantages, and limits of novel interconnects for post-CMOS logic that can augment or eventually replace the CMOS logic. Post-CMOS devices are envisaged on the idea of using state variables other than the electron charge to store and manipulate information. In the first component of the thesis, a comprehensive analysis of the performance and the energy dissipation of novel logic based on various state variables is conducted, and it is demonstrated that the interconnects will continue to be a major challenge even for post-CMOS logic. The second component of the thesis is focused on the analysis of the interconnection aspects of spin-based logic. This research goal is accomplished through the development of physically-based models of spin-transport parameters for various metallic, semiconducting, and graphene nanoribbon interconnects by incorporating the impact of size effects for narrow cross-sectional dimensions of all-spin logic devices. Due to the generic nature of the models, they can be used in the analysis of spin-based devices to study their functionality and performance more accurately. The compact nature of the models allows them to be easily embedded into the developing CAD tools for spintronic logic. These models then provide the foundation for (i) analyzing the spin injection and transport efficiency in an all-spin logic circuit with various interconnect materials, and (ii) estimating the repeater-insertion requirements in all-spin logic, and (iii) estimating the maximum circuit size for all-spin logic. The research is crucial in pinpointing the implications of the physical limits of novel interconnects at the material, device, circuit, and architecture levels.

Trends toward increased integration and miniaturization of optical system components have created pressure to consolidate widely disparate analog and digital functions onto fewer and fewer chips with a goal of eventually built into a single mixed-signal chip. Yet, because of those performance requirements, the frontend circuit has traditionally used III-V compound semiconductor technologies, but the low-level of integration with other digital ICs limits the sustainability of such end products for short-distance applications. On the other hand, their CMOS counter parts, despite having such advantages as low power consumption, high yield that lowers the cost of fabrication, and a higher degree of integration, have not performed well enough to survive in such a noisy environment without sacrificing other important attributes. In this research, a high-speed CMOS preamplifier was designed and fabricated through TSMC 0.18/spl mu/m mixed-signal non-epi CMOS technology, and a 20/spl mu/m diameter InGaAs thin-film Inverted-MSM photodetector with a responsivity of 0.15A/W at a wavelength of 1550/spl mu/m was post-integrated onto the circuit. The circuit has a overall transimpedance gain of 60dB/spl Omega/, and bit-error-rate data and eye-diagram measurement results taken as high as 10Gbit/s are reported in this dissertation.