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Design, Characterization and Analysis of Component Level Electrostatic Discharge (ESD) Protection SolutionsLuo, Sirui 01 January 2015 (has links)
Electrostatic Discharges (ESD) is a significant hazard to electronic components and systems. Based on a specific process technology, a given circuit application requires a customized ESD consideration that meets all the requirements such as the core circuit's operating condition, maximum accepted leakage current, breakdown conditions for the process and overall device sizes. In every several years, there will be a new process technology becomes mature, and most of those new technology requires custom design of effective ESD protection solution. And usually the design window will shrinks due to the evolving of the technology becomes smaller and smaller. The ESD related failure is a major IC reliability concern and results in a loss of millions dollars each year in the semiconductor industry. To emulate the real word stress condition, several ESD stress models and test methods have been developed. The basic ESD models are Human Body model (HBM), Machine Mode (MM), and Charge Device Model (CDM). For the system-level ESD robustness, it is defined by different standards and specifications than component-level ESD requirements. International Electrotechnical Commission (IEC) 61000-4-2 has been used for the product and the Human Metal Model (HMM) has been used for the system at the wafer level. Increasingly stringent design specifications are forcing original equipment manufacturers (OEMs) to minimize the number of off-chip components. This is the case in emerging multifunction mobile, industrial, automotive and healthcare applications. It requires a high level of ESD robustness and the integrated circuit (IC) level, while finding ways to streamline the ESD characterization during early development cycle. To enable predicting the ESD performance of IC's pins that are directly exposed to a system-level stress condition, a new the human metal model (HMM) test model has been introduced. In this work, a new testing methodology for product-level HMM characterization is introduced. This testing framework allows for consistently identifying ESD-induced failures in a product, substantially simplifying the testing process, and significantly reducing the product evaluation time during development cycle. It helps eliminates the potential inaccuracy provided by the conventional characterization methodology. For verification purposes, this method has been applied to detect the failures of two different products. Addition to the exploration of new characterization methodology that provides better accuracy, we also have looked into the protection devices itself. ICs for emerging high performance precision data acquisition and transceivers in industrial, automotive and wireless infrastructure applications require effective and ESD protection solutions. These circuits, with relatively high operating voltages at the Input/Output (I/O) pins, are increasingly being designed in low voltage Complementary Metal-Oxide-Semiconductor (CMOS) technologies to meet the requirements of low cost and large scale integration. A new dual-polarity SCR optimized for high bidirectional blocking voltages, high trigger current and low capacitance is realized in a sub 3-V, 180-nm CMOS process. This ESD device is designed for a specific application where the operating voltage at the I/O is larger than that of the core circuit. For instance, protecting high voltage swing I/Os in CMOS data acquisition system (DAS) applications. In this reference application, an array of thin film resistors voltage divider is directly connected to the interface pin, reducing the maximum voltage that is obtained at the core device input down to ± 1-5 V. Its ESD characteristics, including the trigger voltage and failure current, are compared against those of a typical CMOS-based SCR. Then, we have looked into the ESD protection designs into more advanced technology, the 28-nm CMOS. An ESD protection design builds on the multiple discharge-paths ESD cell concept and focuses the attention on the detailed design, optimization and realization of the in-situ ESD protection cell for IO pins with variable operation voltages. By introducing different device configurations fabricated in a 28-nm CMOS process, a greater flexibility in the design options and design trade-offs can be obtained in the proposed topology, thus achieving a higher integration and smaller cell size definition for multi-voltage compatibility interface ESD protection applications. This device is optimized for low capacitance and synthesized with the circuit IO components for in-situ ESD protection in communication interface applications developed in a 28-nm, high-k, and metal-gate CMOS technology. ESD devices have been used in different types of applications and also at different environment conditions, such as high temperature. At the last section of this research work, we have performed an investigation of several different ESD devices' performance under various temperature conditions. And it has been shown that the variations of the device structure can results different ESD performance, and some devices can be used at the high temperature and some cannot. And this investigation also brings up a potential threat to the current ESD protection devices that they might be very vulnerable to the latch-up issue at the higher temperature range.
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THERMAL METROLOGY AND CHARACTERIZATION OF HIGH THERMAL CONDUCTIVITY POLYMER FIBERS AND FABRICSAaditya Candadai (10277555) 16 March 2021 (has links)
<p>Recent
technological advances in the field of electronics and the accompanying trend
of device miniaturization with enhanced functionality has led to growing
interest in new methods of electronic device integration. As a result,
flexible, wearable, and portable electronic devices have emerged as a way of
providing a multifunctional infrastructure to facilitate various consumer
needs, creating new challenges for materials development. Polymers possess a
unique combination of desirable properties such as mechanical compliance,
durability, low density and chemical stability which makes them ideally
suitable as substrate materials to cater to such diverse applications. However,
the low thermal conductivity of polymers hinders their heat spreading
capability in thermal management applications for flexible and wearable
devices. In recent years, there has been a growing interest in ultra-high
molecular weight polyethylene (UHMW-PE) materials with aligned polymer chains
due to their remarkably high thermal conductivity that is similar to some
metals. These are commercially manufactured in large volumes as fibers using
gel-spinning and ultra-drawing processes that impart a high degree of
crystallinity and orientation to the polymer chains. As a result, these
materials develop exceptionally high mechanical strength, elastic modulus, and
thermal conductivity compared to conventional polymers. Therefore, UHMW-PE
materials have found applications in commercial products like motorcycle gear
and ballistic vests, but have not been commercially deployed for heat spreading
and thermal management applications. While there has been much fundamental work
on the development of high thermal conductivity fibers, effective translation
of the high conductivity from individual fibers to macroscale (wearable)
flexible fabrics has not been previously explored. The objective of this thesis
is to obtain a fundamental understanding of the thermal transport properties of
fabric materials constructed from the high conductivity polymer fibers, and assess
their applicability for potential heat spreading applications. </p>
<p>In the present
work, commercially available high thermal conductivity fibers made of UHMW-PE
are utilized to fabricate plain-weave fabrics prototypes, and the thermal
properties of individual fibers, yarns, and woven fabrics are measured using a
novel in-plane thermal measurement method. The characterization technique
leverages infrared (IR) microscopy for a non-contact temperature sensing and is
generally scalable for thermal characterization of the in-plane
thermal-conductivity of materials across different length scales. Effective
thermal conductivities on the order of ~10 Wm<sup>-1</sup>K<sup>-1</sup> are
achieved along the in-plane dominant heat transport direction of the woven
fabric, which is exceptionally high (~2-3 orders of magnitude) compared to
conventional clothing and textile-based materials. The thermal conductivity and
mechanical flexibility of the UHMW-PE fabrics are benchmarked with respect to
conventional materials and the effect of bend-stressing and thermal annealing
of the fabrics is characterization using the developed metrology. </p>
<p>Additionally, a
laser-based IR thermal metrology technique leveraging both non-contact heating
and temperature sensing is conceptualized and validated using a numerical
thermal modeling approach. The proposed technique provides an approach to
estimate the in-plane heat spreading properties of anisotropic materials with
direction-depended thermal properties based on quantifying the surface
temperature map of a sample subjected to periodic heating. Numerical
simulations are leveraged to demonstrate the applicability of this method to
enable measurement of a wide range of thermal properties indicating great
potential to develop this further as a standardized robust method for in-plane
anisotropic thermal characterization of materials such as fabrics and films.</p>
<p>This work sheds
light on the high thermal conductivity of UHMW-PE materials that can be
achieved using a scalable manufacturing process and describes the thermal metrology
approaches to enable their characterization, thereby providing a foundation for
the conceptualization and design of flexible substrate based thermal solutions
in future wearable/flexible electronic devices.</p>
<p> </p>
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