Materials Issues and Characterization of Low-k Dielectric Materials

MRS Bulletin ◽  
1997 ◽  
Vol 22 (10) ◽  
pp. 49-54 ◽  
Author(s):  
E. Todd Ryan ◽  
Andrew J. McKerrow ◽  
Jihperng Leu ◽  
Paul S. Ho
Keyword(s):  
Process Integration ◽  
Dielectric Materials ◽  
Propagation Delay ◽  
Thermomechanical Properties ◽  
General Criterion ◽  
Crosstalk Noise ◽  
Total Delay ◽  
Interlayer Dielectrics ◽  
Performance Improvements ◽  
And Performance

Continuing improvement in device density and performance has significantly affected the dimensions and complexity of the wiring structure for on-chip interconnects. These enhancements have led to a reduction in the wiring pitch and an increase in the number of wiring levels to fulfill demands for density and performance improvements. As device dimensions shrink to less than 0.25 μm, the propagation delay, crosstalk noise, and power dissipation due to resistance-capacitance (RC) coupling become significant. Accordingly the interconnect delay now constitutes a major fraction of the total delay limiting the overall chip performance. Equally important is the processing complexity due to an increase in the number of wiring levels. This inevitably drives cost up by lowering the manufacturing yield due to an increase in defects and processing complexity.To address these problems, new materials for use as metal lines and interlayer dielectrics (ILDs) and alternative architectures have surfaced to replace the current Al(Cu)/SiO2 interconnect technology. These alternative architectures will require the introduction of low-dielectric-constant k materials as the interlayer dielectrics and/or low-resistivity conductors such as copper. The electrical and thermomechanical properties of SiO2 are ideal for ILD applications, and a change to material with different properties has important process-integration implications. To facilitate the choice of an alternative ILD, it is necessary to establish general criterion for evaluating thin-film properties of candidate low-k materials, which can be later correlated with process-integration problems.

Low-Dielectric-Constant Materials for ULSI Interlayer-Dielectric Applications

MRS Bulletin ◽  
1997 ◽  
Vol 22 (10) ◽  
pp. 19-27 ◽  
Author(s):  
Wei William Lee ◽  
Paul S. Ho
Keyword(s):  
Packing Density ◽  
Propagation Delay ◽  
Single Chip ◽  
Crosstalk Noise ◽  
Metal Line ◽  
Total Delay ◽  
Interlayer Dielectric ◽  
Low Dielectric ◽  
Interconnect Delay ◽  
Interconnect Technology

Continuing improvement of microprocessor performance historically involves a decrease in the device size. This allows greater device speed, an increase in device packing density, and an increase in the number of functions that can reside on a single chip. However higher packing density requires a much larger increase in the number of interconnects. This has led to an increase in the number of wiring levels and a reduction in the wiring pitch (sum of the metal line width and the spacing between the metal lines) to increase the wiring density. The problem with this approach is that—as device dimensions shrink to less than 0.25 μm (transistor gate length)—propagation delay, crosstalk noise, and power dissipation due to resistance-capacitance (RC) coupling become significant due to increased wiring capacitance, especially interline capacitance between the metal lines on the same metal level. The smaller line dimensions increase the resistivity (R) of the metal lines, and the narrower interline spacing increases the capacitance (C) between the lines. Thus although the speed of the device will increase as the feature size decreases, the interconnect delay becomes the major fraction of the total delay and limits improvement in device performance.To address these problems, new materials for use as metal lines and interlayer dielectrics (ILD) as well as alternative architectures have been proposed to replace the current Al(Cu) and SiO2 interconnect technology.

scholarly journals A Fuzzy Optimization Model for High-Speed Railway Timetable Rescheduling

2012 ◽  
Vol 2012 ◽  
pp. 1-22 ◽  
Author(s):  
Li Wang ◽  
Yong Qin ◽  
Jie Xu ◽  
Limin Jia
Keyword(s):  
Optimization Model ◽  
High Speed ◽  
Fuzzy Optimization ◽  
Soft Constraints ◽  
Accurate Approximation ◽  
Total Delay ◽  
High Speed Rail ◽  
High Speed Railway ◽  
Tolerance Approach ◽  
Rail Line

A fuzzy optimization model based on improved symmetric tolerance approach is introduced, which allows for rescheduling high-speed railway timetable under unexpected interferences. The model nests different parameters of the soft constraints with uncertainty margin to describe their importance to the optimization purpose and treats the objective in the same manner. Thus a new optimal instrument is expected to achieve a new timetable subject to little slack of constraints. The section between Nanjing and Shanghai, which is the busiest, of Beijing-Shanghai high-speed rail line in China is used as the simulated measurement. The fuzzy optimization model provides an accurate approximation on train running time and headway time, and hence the results suggest that the number of seriously impacted trains and total delay time can be reduced significantly subject to little cost and risk.

A global grid model for the correction of the vertical zenith total delay based on a sliding window algorithm

GPS Solutions ◽  
2021 ◽  
Vol 25 (3) ◽  
Author(s):  
Liangke Huang ◽  
Ge Zhu ◽  
Lilong Liu ◽  
Hua Chen ◽  
Weiping Jiang
Keyword(s):  
Sliding Window ◽  
Total Delay ◽  
Grid Model ◽  
Zenith Total Delay ◽  
Global Grid

Time Synchronization in Tandem Hot Strip Line Based on Improved Broadcast Mode

2013 ◽  
Vol 341-342 ◽  
pp. 679-683
Author(s):  
Jian Zhao Cao ◽  
Dian Hua Zhang
Keyword(s):  
Control System ◽  
Process Control ◽  
Time Synchronization ◽  
Process Control System ◽  
New Method ◽  
Strip Line ◽  
Total Delay ◽  
Synchronization Problem ◽  
Hot Strip ◽  
Distributed Process

In order to solve the time synchronization problem in tandem hot strip line, the traditional algorithm of time synchronization was analyzed, and the server-client mode was compared with the broadcast mode using multithread technology, then the present paper improved the broadcast mode to improve its precision. The new method can estimate total delay including clock offset and network transmission time. A simple, easy and little loading time synchronization method was designed for the distributed process control system of tandem hot strip line. The new method was applied in domestic some tandem hot strip line successfully which showed that it could meet the demands of process control system with little expenses, simple structure and high precision.

Urban Oversaturated Traffic Network Control Based on Preference Multi-Objective Compatible Optimization Control

2011 ◽  
Vol 317-319 ◽  
pp. 1373-1384 ◽  
Author(s):  
Juan Chen ◽  
Chang Liang Yuan
Keyword(s):  
Control Problem ◽  
Control Algorithm ◽  
Control Method ◽  
Network Control ◽  
Feasible Region ◽  
Traffic Network ◽  
Total Delay ◽  
Multi Objective ◽  
Optimization Control ◽  
Objective Control

To solve the traffic congestion control problem on oversaturated network, the total delay is classified into two parts: the feeding delay and the non-feeding delay, and the control problem is formulated as a conflicted multi-objective control problem. The simultaneous control of multiple objectives is different from single objective control in that there is no unique solution to multi-objective control problems(MOPs). Multi-objective control usually involves many conflicting and incompatible objectives, therefore, a set of optimal trade-off solutions known as the Pareto-optimal solutions is required. Based on this background, a modified compatible control algorithm(MOCC) hunting for suboptimal and feasible region as the control aim rather than precise optimal point is proposed in this paper to solve the conflicted oversaturated traffic network control problem. Since it is impossible to avoid the inaccurate system model and input disturbance, the controller of the proposed multi-objective compatible control strategy is designed based on feedback control structure. Besides, considering the difference between control problem and optimization problem, user's preference are incorporated into multi-objective compatible control algorithm to guide the search direction. The proposed preference based compatible optimization control algorithm(PMOCC) is used to solve the oversaturated traffic network control problem in a core area of eleven junctions under the simulation environment. It is proved that the proposed compatible optimization control algorithm can handle the oversaturated traffic network control problem effectively than the fixed time control method.

TOMOREF operator as a tool to improve weather forecasts

2021 ◽  
Author(s):  
Natalia Hanna ◽  
Estera Trzcina ◽  
Maciej Kryza ◽  
Witold Rohm
Keyword(s):  
Data Assimilation ◽  
Weather Forecasting ◽  
Positive Impact ◽  
Precipitation Event ◽  
Initial State ◽  
Total Delay ◽  
Numerical Weather ◽  
Numerical Weather Model ◽  
Weather Model ◽  
Tomography Data

<p>The numerical weather model starts from the initial state of the Earth's atmosphere in a given place and time. The initial state is created by blending the previous forecast runs (first-guess), together with observations from different platforms. The better the initial state, the better the forecast; hence, it is worthy to combine new observation types. The GNSS tomography technique, developed in recent years, provides a 3-D field of humidity in the troposphere. This technique shows positive results in the monitoring of severe weather events. However, to assimilate the tomographic outputs to the numerical weather model, the proper observation operator needs to be built.</p><p>This study demonstrates the TOMOREF operator dedicated to the assimilation of the GNSS tomography‐derived 3‐D fields of wet refractivity in a Weather Research and Forecasting (WRF) Data Assimilation (DA) system. The new tool has been tested based on wet refractivity fields derived during a very intense precipitation event. The results were validated using radiosonde observations, synoptic data, ERA5 reanalysis, and radar data. In the presented experiment, a positive impact of the GNSS tomography data assimilation on the forecast of relative humidity (RH) was noticed (an improvement of root‐mean‐square error up to 0.5%). Moreover, within 1 hour after assimilation, the GNSS data reduced the bias of precipitation up to 0.1 mm. Additionally, the assimilation of GNSS tomography data had more influence on the WRF model than the Zenith Total Delay (ZTD) observations, which confirms the potential of the GNSS tomography data for weather forecasting.</p>

Evaluation of the zenithal total delay estimates from BeiDou/GPS combined signals in the frame of the IGS MGEX project

2018 ◽  
Vol 54 (1) ◽  
pp. 71-87
Author(s):  
Peng Feng ◽  
Fei Li ◽  
Jianguo Yan ◽  
J.-P. Barriot
Keyword(s):  
Total Delay

scholarly journals An investigation into factors causing delays in highway construction projects in iraq

2018 ◽  
Vol 162 ◽  
pp. 02035
Author(s):  
Bevian I. Al Hadithi
Keyword(s):  
Construction Projects ◽  
Highway Construction ◽  
Rank Correlation ◽  
Weather Conditions ◽  
Well Being ◽  
Transport Sector ◽  
Total Delay ◽  
Occurrence Data ◽  
Political Realities ◽  
Political Decisions

The highways sector is a prominent sector in any country’s economy because of its impact on the well-being and safety of its citizens. The transport sector has an impact on social improvement and investment in the nation on the illustration that allows access to markets, production, jobs, health and other social services.This study investigates the causes of delay of highway construction projects in Iraq, which is frequent occurrence. Data was collected using questionnaires which were distributed to the key project participants; contractors, owners and consultants. The data were analyzed using the Frequency index and Spearman‟s rank correlation. The top seven causes of project delays were observed to be political decisions and political realities, the economic crisis of the country, delays in materials test of and obtaining the results, delay in monthly payments of contractor, failure treatment of the delays when implementing the project, the effects of weather, rain and high temperatures, delay in activities during implementation. It is recommended to establish an appropriate number of laboratories and adopt the field laboratory mechanism for the external and remote screens. Owners should give special attention to pay progress payment to contractors on time. The competent contractor who has prior experience in implementing the high projects should be selected. The contractor must take into consideration the weather conditions when preparing the time plan necessary to implement the project. The project management should identify these reasons and deal with them quickly in order to reduce the total delay of the project.

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