Impact of three-dimensional architectures on interconnects ingigascale integration

An interconnect distribution model for homogeneous, three-dimensional (3-D) architectures with variable separation of strata is presented. Three-dimensional architectures offer an opportunity to reduce the length of the longest interconnects. The separation of strata has little impact on the length of interconnects but a large impact on the number of interstratal interconnects. Using a multilevel interconnect methodology for an ITRS 2005 100 nm ASIC, a two-strata architecture offers a 3.9× increase in wire-limited clock frequency, an 84% decrease in wire-limited area or a 25% decrease in the number of metal levels required. In practice, however, such fabrication advances as improved alignment tolerances in wafer-bonding techniques are needed to gain key advantages stemming from 3-D architectures for homogeneous gigascale integrated circuits     

Annealing textures of copper damascene interconnects for ultra-large-scale integration

The annealing textures of copper interconnects depend upon their deposition textures and geometries. The copper interconnects are subjected to tensile stresses even at room temperature, which in turn gives rise to strain energies. The stress distributions in interconnects are not homogeneous due to trenches, resulting in non-fiber-type textures after annealing. To better understand the formation of the non-fiber-type textures, the textures of specimens of 0.2–6 μm in trench width with 0.2 μm in space were measured, and the strain energy and stress distributions have been simulated. The simulation results indicate that strain energy density is highest at the upper corners of trench. Therefore, the grain growth rate at the upper corners is fastest, resulting in the {111}〈110〉 annealing texture. As the trench width increases, the influence of stresses in the trench increases, even though the strain energy density in the trench is relatively low. In this case the {111}〈112〉 component increases, even though the formation of the {111}〈110〉 orientation cannot be excluded.     

COFDM: an overview

The research and development of OFDM/COFDM for digital television broadcasting has received considerable attention and has made a great deal of progress in Europe. OFDM/COFDM has already been implemented in digital audio broadcasting and is being considered for terrestrial digital television and HDTV broadcasting. The advantages of COFDM claimed by the advocates in Europe have also caught the attention of US broadcasters and generated enthusiasm although a digital modulation technique called 8-VSB has been selected by the FCC Advisory Committee on Advanced Television Service (ACATS) for the final testing. There is considerable debate in the industry over the use of COFDM vs. VSB or QAM for terrestrial HDTV broadcasting. In this paper, the history of research and development on OFDM and COFDM is reviewed. Then, the basic principles, performance and implementation of OFDM and COFDM are examined. Analysis is given to enable the selection of key elements for meeting the constraints of the required applications. Based on the ATV channel model, performance expectation of COFDM under imperfect channel conditions and implementation issues are examined in details     

Contact resistance measurement of bonded copper interconnects for three-dimensional integration technology

A novel test structure for contact resistance measurement of bonded copper interconnects in three-dimensional integration technology is proposed and fabricated. This test structure requires a simple fabrication process and eliminates the possibility of measurement errors due to misalignment during bonding. Specific contact resistances of bonding interfaces with different interconnect sizes of approximately 10/sup -8/ /spl Omega/-cm/sup 2/ are measured. A reduction in specific contact resistance is obtained by longer anneal time. The specific contact resistance of bonded interconnects with longer anneal time does not change with interconnect sizes.     

High-performance germanium-seeded laterally crystallized TFTs forvertical device integration

Increasing chip complexity and area has resulted in interconnect delay becoming a significant fraction of overall chip delay. Continued scaling of design rules will further aggravate this problem. Vertical integration of devices will enable a substantial reduction in chip size and thus in interconnect delay. We present a novel technique to achieve vertical integration of CMOS devices. Germanium is used as a seeding agent at the source and/or drain of thin film transistors (TFTs) to laterally crystallize amorphous silicon films, resulting in high-performance devices. This is achieved through the formation of large grain polysilicon with a precise control over the location of the grain. TFTs have been demonstrated offering substantial performance improvement over conventional unseeded polycrystalline TFTs, with demonstrated mobilities as high as 300 cm2/V-s. The process is fully CMOS compatible and has a low thermal budget. It is highly scalable to deep-submicron technologies and, with suitable optimization, should enable the production of high-performance, high density, vertically integrated ULSI     

Analysis and optimization of shielded RLC global interconnects for gigascale integration

Compact physical models are presented for on-chip double-sided shielded transmission lines, which are mainly used for long global interconnects where inductance effects should not be ignored. The models are then used to optimize the width and spacing of long global interconnects with repeater insertion. The impacts of increasing line width and spacing on various performance parameters such as delay, data-flux density, power dissipation and total repeater area are analysed. The product of data-flux density and reciprocal delay per unit length are defined as a figure of merit (FOM). By maximizing the FOM, the optimal width and spacing of shielded RLC global interconnects are obtained for various international technology roadmap for semiconductors (ITRS) technology nodes.     

The evolution of multi-level air gap integration towards 32 nm node interconnects

Advanced copper interconnects need porous low-k materials to obtain low interline capacitances. A number of porous low-k integration issues have however delayed the introduction of these fragile dielectrics. Replacing the porous low-k dielectric by air is a viable alternative for future technology nodes. Air gaps are not only less prone to integration issues such as plasma damage, but they also enable extremely low capacitances since the permittivity of air is close to 1. In this paper, the evolution of the main air gap integration techniques, from micron-sized aluminum interconnect to copper interconnect for the 32 nm node are discussed in terms of integration complexity, reliability and manufacturability.     

An overview of electrical characterization techniques and theory for IC packages and interconnects

This paper reviews current approaches to the electrical characterization and modeling of IC packages and interconnects. An overview of both frequency and time-domain measurement methods and summaries of equivalent circuit model selection and extraction methodologies are included. Additionally, an overview of numerical methods for electromagnetic modeling is included for completeness. Finally, relevant case studies from the literature are summarized to further supplement the discussed techniques. The focus is primarily on high-frequency signal related characterization and power integrity issues are not directly considered in this paper. This paper is presented in the context of the growing requirement for package and interconnection electrical models for high-speed and miniaturized systems.     

Multimedia systems: an overview

Advances in distributed multimedia systems have begun to significantly affect the development of on-demand multimedia services. Researchers are working within established computer areas to transform existing technologies and develop new ones. Multimedia is shown as the merging of computing, communications, and broadcasting     

Virtual studios: an overview

Virtual studio systems began as experimental prototypes that extended traditional chromakeying. Now commercial products based on graphics supercomputers are commonly used for broadcast production. We discuss this evolution and consider extensions, alternative approaches, and issues facing broadcasters who introduce virtual studio systems     

Teleaction services: an overview

Many large industries are beginning to decide whether they will use simple, low-speed data communications. These low-speed services may be the first data services that most small business and residence customers buy because the market already needs them. As a group, they are called teleaction services. The term teleaction means "acting at a distance." The actions include reading or writing some information to remote locations, or possibly both. Instead of sending a person to set or read some information on a device, it is done remotely via a communications network. This form of data collection is especially useful when coupled with a computer system that could use the data to initiate action. Currently, some of these services have low market penetration. However, the market need for them is real, and potential users consistently express interest in them. The challenge is to be able to deliver them in a cost-effective way. The purpose of the article is to provide a review of these services. The author provides a classification and an overview of current and emerging services with an emphasis on the specific business aspects of each service and each market segment. Then, the business drivers are discussed from the perspectives of the end user, the service provider, and the communications carrier     

SAR calibration: an overview

Progress in synthetic-aperture radar, (SAR) calibration is reviewed. The difficulties of calibrating both airborne and spaceborne SAR image data are addressed. The quantities measured by a SAR, i.e. radar backscatter, are defined and mathematical formulations for the three basic types of SAR image are developed. The difficulties in establishing science requirements for calibration are discussed. The measurement of SAR image quality is briefly addressed. The problem of radiometric calibration is introduced via the SAR form of the radar equation, with both internal and external calibration approaches considered. The development of algorithms for polarimetric radar calibration is reviewed and the problems involved in phase calibration of interferometric SAR are discussed. Future challenges in the field of SAR calibration are considered     

Meteor scatter: an overview

The phenomenon of radio propagation using meteor trails is reviewed. Underdense and overdense propagation mechanisms are described. The multipath and fading profile of the meteor channel is examined. Mechanisms other than meteor trails that are commonly observed on meteor links and can change the characteristics of the meteor communication channel are considered. These include sporadic-E propagation, auroral scatter, ionospheric scatter, diffraction, line-of-sight propagation, and tropospheric scatter     

Monolayer metallic nanotube interconnects: promising candidates for short local interconnects

Mono- or bi-layer metallic single-wall carbon nanotube interconnects have lateral capacitances more than four times smaller than those of copper interconnects. The resistance and time-of-flight of these monolayer nanotubes would be larger than that of copper interconnects. For short lengths, however, driver resistance is quite dominant, and latency is determined by interconnect capacitance. Monolayer nanotube interconnects are therefore promising candidates for local interconnects. The average capacitance per unit length of these nanotube interconnects can be 50% smaller than that of copper interconnects and that leads to significant saving in power dissipation.     

Photonics-to-electronics integration for optical interconnects in the early 21st century

It is useful to examinethe history of penetration opti-cal datalinksinto communication over thelast 30 years .Fig.1 shows an approxi mate perspective of the rate ofpenetration of optics versus the link distance and thebandwidth.Thelower horizontal axis re…     

IP router architectures: an overview

In the emerging environment of high performance IP networks, it is expected that local and campus area backbones, enterprise networks, and internet service providers (ISPs) will use multigigabit and terabit networking technologies where IP routers will be used not only to interconnect backbone segments but also to act as points of attachments to high performance wide area links. Special attention must be given to new powerful architectures for routers in order to play that demanding role. In this paper, we identify important trends in router design and outline some design issues facing the next generation of routers. It is also observed that the achievement of high throughput IP routers is possible if the critical tasks are identified and special purpose modules are properly tailored to perform them. Copyright © 2001 John Wiley & Sons, Ltd.     

Wireless telemedicine systems: an overview

Rapid advances in information technology and telecommunications and, more specifically, wireless and mobile communications - and their convergence ("telematics") are leading to the emergence of a new type of information infrastructure that has the potential of supporting an array of advanced services for healthcare. The objective of this paper is to provide a snapshot of the applications of wireless telemedicine systems. A review of the spectrum of these applications and the potential benefits of these efforts is presented, followed by successful case studies in electronic patient record, emergency telemedicine, teleradiology, and home monitoring. It is anticipated that the progress carried out in these efforts and the potential benefits of emerging mobile technologies will trigger the development of more applications, thus enabling the offering of a better service to the citizen     

Simulated annealing algorithms: an overview

A brief introduction is given to the actual mechanics of simulated annealing, and a simple example from an IC layout is used to illustrate how these ideas can be applied. The complexities and tradeoffs involved in attacking a realistically complex design problem are illustrated by dissecting two very different annealing algorithms for VLSI chip floorplanning. Several current research problems aimed at determining more precisely how and why annealing algorithms work are examined. Some philosophical issues raised by the introduction of annealing are discussed     

Power semiconductor devices: an overview

Advances in power semiconductor devices are discussed, focusing on the adaptation of silicon integrated circuit wafer processing methods to the design and fabrication of power devices. Some basic properties of power devices are reviewed, along with recent adaptations of wafer processing technology. Two trends are discerned: increasing use of self-aligned, double diffused MOS gate structures to achieve devices with low-current drive requirements; and movement toward an ideal one-dimensional device, thereby making more efficient use of the available area. Different devices are compared. Techniques that have potential for use in power device are discussed: use of trenches, direct wafer bonding, cellular bipolar transistors, and junction termination. The combination of power switches with control logic on the same chip is briefly considered