Download or read book Finite Element Analysis of Electromigration Failure in Cu Interconnect written by Yuxiang He and published by . This book was released on 2005 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electromigration in ULSI Interconnections written by Cher Ming Tan and published by World Scientific. This book was released on 2010 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electromigration in ULSI Interconnections provides a comprehensive description of the electro migration in integrated circuits. It is intended for both beginner and advanced readers on electro migration in ULSI interconnections. It begins with the basic knowledge required for a detailed study on electro migration, and examines the various interconnected systems and their evolution employed in integrated circuit technology. The subsequent chapters provide a detailed description of the physics of electro migration in both Al- and Cu-based Interconnections, in the form of theoretical, experimental and numerical modeling studies. The differences in the electro migration of Al- and Cu-based interconnections and the corresponding underlying physical mechanisms for these differences are explained. The test structures, testing methodology, failure analysis methodology and statistical analysis of the test data for the experimental studies on electro migration are presented in a concise and rigorous manner.Methods of numerical modeling for the interconnect electro migration and their applications to the understanding of electro migration physics are described in detail with the aspects of material properties, interconnection design, and interconnect process parameters on the electro migration performances of interconnects in ULSI further elaborated upon. Finally, the extension of the studies to narrow interconnections is introduced, and future challenges on the study of electro migration are outlined and discussed.

Download or read book Electromigration In Ulsi Interconnections written by Cher Ming Tan and published by World Scientific. This book was released on 2010-06-25 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electromigration in ULSI Interconnections provides a comprehensive description of the electromigration in integrated circuits. It is intended for both beginner and advanced readers on electromigration in ULSI interconnections. It begins with the basic knowledge required for a detailed study on electromigration, and examines the various interconnected systems and their evolution employed in integrated circuit technology. The subsequent chapters provide a detailed description of the physics of electromigration in both Al- and Cu-based Interconnections, in the form of theoretical, experimental and numerical modeling studies. The differences in the electromigration of Al- and Cu-based interconnections and the corresponding underlying physical mechanisms for these differences are explained.The test structures, testing methodology, failure analysis methodology and statistical analysis of the test data for the experimental studies on electromigration are presented in a concise and rigorous manner. Methods of numerical modeling for the interconnect electromigration and their applications to the understanding of electromigration physics are described in detail with the aspects of material properties, interconnection design, and interconnect process parameters on the electromigration performances of interconnects in ULSI further elaborated upon. Finally, the extension of the studies to narrow interconnections is introduced, and future challenges on the study of electromigration are outlined and discussed.

Download or read book Electromigration in Cu Interconnects written by Dr. Arijit Roy and published by LAP Lambert Academic Publishing. This book was released on 2011-07 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is intended for the beginners and the advanced readers. Electromigration is VLSI/ULSI interconnection remains one of the major failure issues in microelectronics and electromigration remains an attractive research area in last few decades. This work attempts to explore the driving force formalism of the electromigration phenomenon.The prime interest of this work is to investigate the physics of failure in submicron (down to 100 nm wide) Cu interconnections including the effect of surrounding materials. A combined driving force model, including the forces from the stress and temperature gradients is presented. In order to develop the combined driving force model, commercial finite element analysis package is used. Plenty of experiments on Cu damascene interconnects are conducted, and extensive failure analyses are performed to investigate the root causes of electromigration failure. Good correlations between the model predictions and experiments are obtained. The future challenges on the study of electromigration are also discussed.

Download or read book Applications of Finite Element Methods for Reliability Studies on ULSI Interconnections written by Cher Ming Tan and published by Springer Science & Business Media. This book was released on 2011-03-28 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: Applications of Finite Element Methods for Reliability Studies on ULSI Interconnections provides a detailed description of the application of finite element methods (FEMs) to the study of ULSI interconnect reliability. Over the past two decades the application of FEMs has become widespread and continues to lead to a much better understanding of reliability physics. To help readers cope with the increasing sophistication of FEMs’ applications to interconnect reliability, Applications of Finite Element Methods for Reliability Studies on ULSI Interconnections will: introduce the principle of FEMs; review numerical modeling of ULSI interconnect reliability; describe the physical mechanism of ULSI interconnect reliability encountered in the electronics industry; and discuss in detail the use of FEMs to understand and improve ULSI interconnect reliability from both the physical and practical perspective, incorporating the Monte Carlo method. A full-scale review of the numerical modeling methodology used in the study of interconnect reliability highlights useful and noteworthy techniques that have been developed recently. Many illustrations are used throughout the book to improve the reader’s understanding of the methodology and its verification. Actual experimental results and micrographs on ULSI interconnects are also included. Applications of Finite Element Methods for Reliability Studies on ULSI Interconnections is a good reference for researchers who are working on interconnect reliability modeling, as well as for those who want to know more about FEMs for reliability applications. It gives readers a thorough understanding of the applications of FEM to reliability modeling and an appreciation of the strengths and weaknesses of various numerical models for interconnect reliability.

Download or read book Electromigration Analysis of High Current Carrying Adhesive based Copper to copper Interconnections written by Sadia Arefin Khan and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "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.

Download or read book Fundamentals of Electromigration Aware Integrated Circuit Design written by Jens Lienig and published by Springer. This book was released on 2018-02-23 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book provides a comprehensive overview of electromigration and its effects on the reliability of electronic circuits. It introduces the physical process of electromigration, which gives the reader the requisite understanding and knowledge for adopting appropriate counter measures. A comprehensive set of options is presented for modifying the present IC design methodology to prevent electromigration. Finally, the authors show how specific effects can be exploited in present and future technologies to reduce electromigration’s negative impact on circuit reliability.

Download or read book Elements of Electromigration written by King-Ning Tu and published by CRC Press. This book was released on 2024-01-19 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this invaluable resource for graduate students and practicing professionals, Tu and Liu provide a comprehensive account of electromigration and give a practical guide on how to manage its effects in microelectronic devices, especially newer devices that make use of 3D architectures. In the era of big data and artificial intelligence, next-generation microelectronic devices for consumers must be smaller, consume less power, cost less, and, most importantly, have higher functionality and reliability than ever before. However, with miniaturization, the average current density increases, and so does the probability of electromigration failure. This book covers all critical elements of electromigration, including basic theory, various failure modes induced by electromigration, methods to prevent failure, and equations for predicting mean-time-to-failure. Furthermore, effects such as stress, Joule heating, current crowding, and oxidation on electromigration are covered, and the new and modified mean-time-to-failure equations based on low entropy production are given. Readers will be able to apply this information to the design and application of microelectronic devices to minimize the risk of electromigration-induced failure in microelectronic devices. This book essential for anyone who wants to understand these critical elements and minimize their effects. It is particularly valuable for both graduate students of electrical engineering and materials science engineering and engineers working in the semiconductor and electronic packaging technology industries.

Download or read book Modeling of and Experiments Characterizing Electromigration induced Failures in Interconnects written by Vaibhav Kumar Andleigh and published by . This book was released on 2001 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) A failure mechanism map constructed for damascene Cu demonstrates the absence of immortality by resistance saturation due to the shunt structure. Finally, proposed damascene designs eliminating the diffusion barrier at the studs may be expected to have an adverse effect on interconnect reliability due to the loss of short length effects. The test structure developed in this thesis provides a simple means of testing the effects of new shunt and barrier layer technologies on the reliability of Cu-based interconnects. Through the use of the simulation, an accurate methodology for predicting the reliability of Al- and Cu-based interconnects in semiconductor chips has been developed. MIT/EmSim is now being used by Motorola and LSI Logic for evaluating interconnect reliability during the design of future Cu interconnects, and has also been used by numerous SRC-companies and universities through EmSim-Web for electromigration research.

Download or read book To Eliminate Electromigration Induced Failure in Cu Interconnect Technology written by Minyu Yan and published by . This book was released on 2005 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Statistical modeling reliability analysis for electromigration early failure and mass transport in cu oxide dual damascene interconnects written by Ki-don Lee and published by . This book was released on 2000 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Electromigration in Single and Dual inlaid Cu Interconnects written by Patrick Ryan Justison and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the International Symposium on the Physical Failure Analysis of Integrated Circuits written by and published by . This book was released on 2005 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Constrained Deformation of Materials written by Y.-L. Shen and published by Springer Science & Business Media. This book was released on 2010-08-09 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Constrained Deformation of Materials: Devices, Heterogeneous Structures and Thermo-Mechanical Modeling" is an in-depth look at the mechanical analyses and modeling of advanced small-scale structures and heterogeneous material systems. Mechanical deformations in thin films and miniaturized materials, commonly found in microelectronic devices and packages, MEMS, nanostructures and composite and multi-phase materials, are heavily influenced by the external or internal physical confinement. A continuum mechanics-based approach is used, together with discussions on micro-mechanisms, to treat the subject in a systematic manner under the unified theme. Readers will find valuable information on the proper application of thermo-mechanics in numerical modeling as well as in the interpretation and prediction of physical material behavior, along with many case studies. Additionally, particular attention is paid to practical engineering relevance. Thus real-life reliability issues are discussed in detail to serve the needs of researchers and engineers alike.

Download or read book Electromigration Induced Interface Reaction in Cu wire Al pad Diffusion Couple written by Patricia Aracelly Rodriguez-Salazar and published by . This book was released on 2017 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents experimental observations that may assist the understanding of electromigration (EM) failure mechanism active in Cu wire and Al thin film pad (wire bond). This study is motivated by an ongoing industrial effort to adapt Cu as wire bonding material for interconnection. Traditional material used for the wire bond has been Au; however, its high cost combined with its susceptibility to reliability failure caused by excessive growth of IMCs (IMC) makes Cu to be an attractive replacement. Though, since an application of Cu to wire bond technology is relatively new, many of reliability failure mechanisms are unknown especially the ones related to EM reliability as it is increasingly serious in limiting useful life of wire bond. This makes the investigation on EM failure mechanism in Cu to be necessary. One of the most challenging difficulties of EM study is the isolation of the EM from any other effects on the failure process such as an increase in temperature by Joule heating. The Joule heat effect is of particular concern because it is expected to be considerable at wire bond configuration, making failure by EM to proceed concurrently with other failure mechanisms. Our investigation then begins with design of test structure that can prove that wire bond failure is indeed induced by EM, and progresses towards understanding microscopic mechanism by which wire bond becomes failure prone by EM. Therefore, this study proposes the use of a special configuration sample where two interfaces can be tested at the same temperature and current density conditions. The design of the sample includes a two-level interconnect structure pattern on Si substrate where a short strip conductor allows flow of test current from one pad to another. The short distance combined with heat-conduction through Si substrate assists the minimization of temperature gradient between the two interfaces. This design helps to isolate the EM effect over other factors that could contribute to the interface degradation such as Joule heating. The samples are then subjected to various testing conditions of temperature and current density and it is indeed found that there exists a difference in the failure kinetics when the interfaces are compared: the pad where current flows from pad to wire (mass flow is from the wire to pad) always fails faster than the opposite case. If it is considered that both interfaces have been tested at the same temperature and current density, the only factor contributing to this difference will be the EM because it is directional. The dependence of failure rate on the pad in respect to the direction of current flow is also found in Au-Al wire bond which is also tested for comparison purpose. This result indicates that the A-Al and Cu-Al wire bond shares the same failure mechanism when electric current is applied and provides further evidence that EM plays a critical role in inducing degradation in the interface integrity. When the EM failure kinetics of the first failing pad of samples are collected, and analyzed, they are found to follow the classic "Black's equation" that relates the failure rate to current density and test temperature; the failure rate shows current density dependence with exponent close to 2 for both Cu-Al and Au-Al wire bonds and temperature dependency with an activation energy of ~1.2eV for Cu-Al and 0.9eV for Au-Al. While Au-Al and Cu-Al wire bonds do not show typically different EM failure parameters, overall life of Cu-Al wire bond is notably higher (nearly one order of magnitude). This suggests that EM life enhancement in Cu-Al is mainly due to slower diffusion rate of species at the interface, which is consistent with other observations reporting slower IMC growth rate in Cu-Al than in Au-Al wire bond interface. In order to understand the EM mechanism leading to failure, microstructure of the interface is closely inspected after EM testing. This study shows that the growth of IMC is enhanced at the failing pad where EM forces IMC to grow into Al pad. Both Cu-Al and Au-Al shows the same trend, that is that the growth of IMC is substantially enhanced by EM when it is directed from the wire to the Al pad. This is consistent with a common expectation that the growth of IMC layers leads to the interface failure and EM makes the failure to be accelerated by speeding up their growth. However, it is noticed that there exists a distinctive difference in failure morphology between Au-Al and Cu-Al wire bond interface. The difference is that the damage at Au-Al interface appears as an extended voiding, while such voiding is absent in case of Cu-Al interface. Instead, it appears that the damage proceeds by the growth of cracks. It is believed that slow interdiffusion rate in Cu-Al interface makes the Kirkendall voiding to be suppressed from its formation while other factors like interface strain becomes primary factor responsible for interface failure. Although EM failure mechanism in Cu-Al wire bond interface is microscopically understood by the use of the theory that EM forces IMC growth to be accelerated when it directs atomic flux towards Al pads where short-circuit diffusion path is available, the difference in activation energy between EM failure and thermal growth rate of IMC phases appears to disagree with the theory. However, EM failure involves multiple processes such as crack initiation and growth in addition to IMC growth, it is possible that its activation energy may not necessarily be the same to that of thermal IMC growth. It is our belief that the cracking is delayed at higher temperature because of active stress relaxation process while such process is suppressed at lower temperature. This can make the activation of EM failure to be higher than that of IMC growth. On the other hand, the microscopic mechanism of EM failure established in this study also provides a reasonable explanation on an abnormal failure behavior at the interface. As is indicated, the failure always occurs faster at the pad where EM flux is directed toward Al pad. However, the rate of failure development is actually the opposite in the beginning EM testing. Initially, the failure rate measured by the interface resistance change is higher at the pad where EM flux is directed toward wire. With progressing of EM, its rate decreases and is eventually slower than the opposite case. This crossover in failure rate does not appear in case of Al-Au wire bond interface but is unmistakably existing in Cu-Al wire bond. This is found to be related to the interplay between the type of IMC phase forming at given time and its contribution to the interface resistance. In the pad where EM is directed toward Cu wire, the growth of high resistance [gamma]-- Cu9Al3 phase is initially more active because EM flux is against the direction of Cu diffusion. As EM progresses, with slow migration of Cu into Al pad, the growth of IMC phases in Al pad is generally suppressed, leading to slower increase in interface resistance. This agrees well with the microstructural mechanism found in our study. So as to better understand EM mechanism, the growth of IMC phases without EM load is investigated by subjecting the samples to only thermal condition. This study is done to compare IMC growth behaviors with and without EM, and also to determine the fundamental mechanism of IMC growth in Cu-Al; wire bond. This study leads to the conclusion that there are three IMC phases possible to grow at interface, and they are [alpha]2--Cu3Al,[gamma]-- Cu9Al4 and [theta] --CuAl2. Interdiffusion makes the CuAl2 phase to form first in Al pad because Al provides fast diffusion path for Cu due to abundant grain boundaries. This gradually consumes Al pad while a portion of CuAl2 is replaced for Cu9Al4. Finally, Cu rich phase, Cu3Al, forms at Cu wire side but its growth is very sluggish due to lack of diffusion short-circuit. As consequence, the three IMC layers form at the interface, mostly consuming Al pad with time. The growth rate of the total IMC layer thickness, all phases combined, follows an ideal diffusion controlled growth kinetics showing (t)1/2 dependence. The activation energy for the growth is observed to be ~0.5 eV, which is far lower than that of EM failure. While our investigation has yielded reasonably self-consistent EM failure mechanism active in Cu-Al wire bond, there still exists a number of subjects that await further investigation. Among many, the question as to the type of IMC phases possible to form at Cu-Al interface requires careful and extensive investigations. The source of stress that initiates the cracking and the type of IMC phase affecting such progress is an unanswered but critical question not only for understanding the fundamental mechanism of interface structure but also for finding ways to improving EM reliability of Cu/Al wire bonds.

Download or read book JOULE HEATING INDUCED INTERCONNECT FAILURE IN 3D IC TECHNOLOGY written by Menglu Li and published by . This book was released on 2016 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the slow-down of Moore's law of scaling transistors, the industry is looking for 3D IC technology to extend the Moore's law by stacking chips vertically. In the 3D IC technology, Joule heating is the most serious reliability concern because of increased power density. Moreover, there are new interconnects in the package to support vertical stacking, including the Through Silicon Via (TSV) inside silicon die, -bumps between different dies, and redistribution layer (RDL) to fan out the current between -bumps and TSVs, and between TSV and flip chip solder joints. Thus, how does joule heating affect the reliability of the new interconnects is of most interest. In this thesis, we applied the electromigration test to induce joule heating in our packaging system, and studied the weak link of the 3D IC system first. It is found that the redistribution layer is the weak link and failed by burn-out voids. The failure mode is evaluated by finite element analysis and found to be joule heating enhanced electromigration. Then, we optimized the redistribution design in the power delivery system to reduce the thermal effect and minimize the IR drop (covered in Chapter 3). It is found that an optimal power distribution system requires larger TSVs integrated at the super fat capture levels (RDL), rather than small TSVs captured at the lower levels. We further evaluated the electromigration resistance of optimized RDL and found that fat wire can pump more current but the surface treatment of Cu RDL limits the maximized current. In Chapter 4, we found that the lateral joule heating transfer through Si interposer will induce high enough temperature gradient inside the un-powered microbumps next to the powered microbumps, and fail the un-powered microbumps by thermomigration. The heat transfer creates a large temperature gradient, in the order of 1000 C/cm, through the un-powered microbumps in the neighboring chip, so the microbumps failed by thermomigration. In our test structure, we have found other microbumps which were failed by electromigraion as well as by constant temperature annealing. We used synchrotron radiation tomography to compare the failure in these three kinds of microbumps: microbumps under electromigration, microbumps under thermomigration, and microbumps under a constant temperature thermal annealing. The results show that the microbumps under thermomigration have the largest damage. Our calculations showed that indeed the electromigration and thermomigration driving force are in the same order. The latter induced atomic flux of Sn to go from the cold end to the hot end, resulting in depletion and void formation at the cold end. Furthermore, the temperature gradient tends to enhance sidewall surface diffusion of Sn to react with Ni and Cu. This sidewall surface diffusion of Sn can cause significant void formation in the solder layer in the microbumps.

Download or read book Defects and Diffusion in Metals written by and published by . This book was released on 2004 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: