Browsing by Author "Chen, LW"

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A novel process and thermodynamic mechanisms of air gap formation for ULSI application
(2000-11-01)
Chang, KM
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Yang, JY
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Chen, LW
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Tseng, MH
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電子工程學系及電子研究所
In this study, a novel process to fill the gap between the metal lines on a wafer with air is developed. Reduction of the parasitic wire capacitance in ULSI has become an important issue for future high-speed and low-power applications. Use of low dielectric constant material as inter-level dielectric (ILD) can overcome this problem. Many new low dielectric constant materials are under study and lower dielectric constant and feasibility are the two goals of these researches. The gas-dielectric process has the lowest dielectric constant, 1.0, and its conceptual feasibility is demonstrated. Basic process characterization data, thermodynamic mechanism and requirements for air gap formation are also discussed. We calculated the relationship among the surface tension, the vaporization rate and atmospheric pressure to construct a model of the process window to show that this process is feasible and reproducible. Scanning electron microscope data show that a large area of air gap can be obtained. Basic electrical characteristics data such as I-V and C-V, measured and compared with the conventional PECVD process, show that the air gap has better isolation than PECVD process. (C) 2000 Elsevier Science S.A. All rights reserved.
A novel technology to form air gap for ULSI application
(1999-04-01)
Chang, KM
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Yang, JY
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Chen, LW
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
In this letter, we develop a novel process to fill the interline space with air (dielectric constant = 1). A silicon wafer, whose face is downward, patterned with metal lines, is placed on the top of another silicon wafer coated with dry polyimide. Hydrogen silsesquioxanes (HSQ), FOx-16, is diluted and trickled through the slit between the metal lines and the polyimide. Then the HSQ forms an ultrathin liquid layer on the dry polyimide and contacts with the top of the metal lines. After the liquid HSQ becomes dry, the air gap is formed, The dry polyimide has good adhesion to silicon substrate but not to the dry FOx-16, so we can separate the polyimide from the dry FOx-16 and get the air gap. The liquid property of HSQ and its high selective adsorption between the metal lines and the polyimide are utilized to form the air gap.
A Stop-or-Move Mobility model for PCS networks and its location-tracking strategies
(2003-07-21)
Tseng, YC
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Chen, LW
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Yang, MH
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Wu, JJ
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資訊工程學系
This paper considers the location-tracking problem in PCS networks. Solutions to this problem in fact highly depend on the mobility patterns of mobile subscribers [ACM DIAL-M (1999) 72]. In the literature, many works have assumed a simple random walk model, where mobile subscribers always stay in a roaming state and can move in any direction with equal probability. In this paper, we propose a new Stop-or-Move Mobility (SMM) model, which is characterized by the following features: 'transition between stop and move', 'infrequent transition', 'memory of roaming direction', and 'oblivious in different moves'. Based on this mobility model, a static and an adaptive location-tracking Scheme are developed. The schemes only need to keep very little information for each user. Analyses and simulations are provided, which show that the proposed schemes are quite prospective. (C) 2003 Elsevier Science B,V. All rights reserved.
Route throughput analysis for mobile multi-rate wireless ad hoc networks
(2004)
Tseng, YC
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Chu, W
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Chen, LW
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Yu, CN
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資訊工程學系
The mobile ad hoc networks (MANETs) have received a lot of attention recently. While many routing protocols have been proposed for MANETs based on different criteria, few have considered the impact of multi-rate communication capability that is supported by many current WLAN products. Given a routing path, this paper provides an analytic tool to evaluate the expected throughput of the route, assuming that hosts move following the discrete-time, random-walk model. The derived result can be added as another metric for route selection. Simulation results tire also presented.