Browsing by Author "Liu, SH"

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A model-based fuzzy logic controller with Kalman filtering for tracking mean arterial pressure
(2001-11-01)
Liu, SH
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Lin, CT
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電控工程研究所
;
Institute of Electrical and Control Engineering
This paper proposes a new noninvasive measurement method for tracking the tendency of mean arterial pressure (MAP) in the radial artery. The designed system consists of a tonometer, a microsyringe device, and a model-based fuzzy logic controller. The modified flexible diaphragm tonometer is to detect the continuous blood pressure waveform and vessel volume pulse. A precise mathematical model describing the interaction between the tonometer and artery is derived. To reach accurate measurement without distortion, a model-based fuzzy logic control system is designed to compensate the change of MAP by applying a counter pressure on the tonometer chamber through the microsyringe device. The proposed control system consists of a linear predictor, a Kalman filter, and a synthetic fuzzy logic controller (SFLC). The linear predictor is to estimate the MAPs changing tendency based on the identified arterial pressure-volume model and then to beat-to-beat adjust the function of SFLC. The Kalman filter is to reduce the physiologic and measurement disturbance of the vessel volume oscillation amplitude (VOA). The SFLC is composed of three parallel subcontrollers, each of which is a simple fuzzy logic controller, for processing the three changing states of the MAP: ascending, descending, and stabilizing states, respectively. The design of the fuzzy rules in each subcontroller is based on the oscillometric principle saying that the arterial vessel has the maximum compliance when the detected vessel volume pulse reaches its maximum amplitude. Simulation results show that, for the real physiologic MAP with changing rates up to 20 or -20 mm-Hg/minute, the model-based SFLC can beat-to-beat adjust the tonometer's chamber pressure to follow the tendency of MAP accurately.
Aging influence of poly(ethylene glycol) suppressors of Cu electrolytes on gaps filling
(2006-05-01)
Liu, SH
;
Li, TC
;
Chen, C
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Shieh, JM
;
Dai, BT
In this study, we investigate how the degradation of poly(ethylene glycol) (PEG) additives in Cu electroplating electrolytes influences the gaps filling of damascene features and the roughness of plated surfaces. The cleavage of PEG, whose reaction is enhanced by a high bias current and more plating cycles, not only diminishes the inhibition effect of the electrolytes, but also enables the formation of enormous complexes of short-chain PEG-Cu far from the reacting surfaces. Hence, the more plating cycles performed, the worse the gaps filling characteristic and the rougher the plated surfaces. Furthermore, an overshoot phenomenon on the transient cells voltage for PEG-containing electrolytes is observed and explained well by a dynamic equilibrium between PEG absorption ability and Cu reduction speed. Accordingly, the change in overshoot shape is closely related to PEG aging and this fact is employed to examine the reliability of electrolytes.
Influence of sheet resistance on N2O-grown polyoxide
(2000-04-01)
Chang, KM
;
Lee, TC
;
Liu, SH
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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
The influence of sheet resistance on polyoxide was explored in this paper. Polyoxides were grown on polysilicon with different sheet resistances (30-150 Omega/cm(2)). It was found that as the sheet resistance increased from 30 Omega/cm(2) to 50 Omega/cm(2) the characteristics of polyoxide was improved with higher breakdown electric field and higher charge-to-breakdown. However, as the sheet resistance continued to increase (> 110 Omega/cm(2)), the characteristics of polyoxide became worse again. This phenomenon is explained by phosphorus concentration incorporated into polyoxide. Phosphorus concentration helps to form a smoother polyoxide/polysilicon interface. Thus, the characteristics of polyoxide with high sheet resistance (>110 Omega/cm(2)) was worse than that of polyoxide with low sheet resistance due to a rough polyoxide interface. However, too much. phosphorus incorporated into polyoxide degrades the quality of polyoxide. So the characteristics of polyoxide with low sheet resistance (<50 Omega/cm(2)) became worse again. Consequently, high quality of polyoxide should he grown on the polysilicon with middle sheet resistance (50-110 Omega/cm(2)).
Model-based synthetic fuzzy logic controller for indirect blood pressure measurement
(2002-06-01)
Wang, JJ
;
Lin, CT
;
Liu, SH
;
Wen, ZC
;
電控工程研究所
In this paper, a new measurement system for the non-invasive monitoring of the continuous blood pressure waveform in the radial artery is presented. The proposed system comprises a model-based fuzzy logic controller, an arterial tonometer and a micro syringe device. The flexible diaphragm tonometer is to register the continuous blood pressure waveform. To obtain accurate measurement without distortion, the tonometer's mean chamber pressure must be kept equal to the mean arterial pressure (MAP), the so-called optimal coupling condition, such that the arterial vessel has the maximum compliance. Since the MAP cannot be measured directly, to keep the optimal coupling condition becomes a tracking control problem with unknown desired trajectory. To solve this dilemma, a model-based fuzzy logic controller is designed to compensate the change of MAP by applying a counter pressure on the tonometer chamber through the micro syringe device. The proposed controller consists of a model-based predictor and a synthetic fuzzy logic controller (SFLC). The model-based predictor is to estimate the MAPs changing tendency based on the identified arterial pressure-volume model. The SFLC is composed of three subcontrollers, each of which is a simple fuzzy logic controller, for processing the three changing states of the MAP: ascending, descending and stabilizing states, respectively. Simulation results show that, for the MAP with changing rates of +/-10, +/-20 or +/-30 mm Hg/min, the model-based SFLC can beat-to-beat adjust the tonometer's chamber pressure only with a mean square error of 1.9, 2.2, or 2.8 nun Hg, respectively.
Reduction of interference in oscillometric arterial blood pressure measurement using fuzzy logic
(2003-04-01)
Lin, CT
;
Liu, SH
;
Wang, JJ
;
Wen, ZC
;
電控工程研究所
In oscillometry, oscillation amplitudes (OAs) embedded in the cuff pressure are drastically affected by a variety of artifacts and cardiovascular diseases, leading to inaccurate arterial blood pressure (ABP) measurement. The purpose of this paper is to improve the accuracy in the arterial pressure measurement by reducing interference in the OAs using a recursive weighted regression algorithm (RWRA). This method includes a fuzzy logic discriminator (FLD) and a recursive regression algorithm. The FLD is used to reduce the effect of artifacts caused by measurement motion disturbance or cardiovascular diseases, and to determine the truthfulness of the oscillation pulse. According to the truth degree, the relationship between the cuff pressure and OA is reconstructed using the regression algorithm. Because the regression method must utilize inverse matrix operation, which will be difficult to implement in an automatic or ambulatory monitor, the recursive regression method is proposed to solve this problem. To test the performance of this RWRA, 47 subjects underwent the ABP measurement using both the auscultation and the oscillometry combined with the RWRA. It was found that the average difference between the pooled blood pressures measured by the auscultation and those by the oscillometry combined with the RWRA was found to be only 4.9 mmHg. Clinical results demonstrated that the proposed RWRA is more robust than the traditional curve fitting algorithm (TCFA). We conclude that the proposed RWRA can be applied to effectively improve the accuracy of the oscillometric blood pressure measurement.
Robot motion command simplification and scaling
(2002-08-01)
Young, KY
;
Liu, SH
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電控工程研究所
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Institute of Electrical and Control Engineering
It has been observed that human limb motions are not very accurate, leading to the hypothesis that the human motor control system may have simplified motion commands at the expense of motion accuracy. Inspired by this hypothesis, we propose learning schemes that trade motion accuracy for motion command simplification. When the original complex motion commands capable of tracking motion accurately are reduced to simple forms, the simplified motion commands can then be stored and manipulated by using learning mechanisms with simple structures and scanty memory resources, and they can be executed quickly and smoothly. This paper also proposes learning schemes that can perform motion command scaling, so that simplified motion commands can be provided for a number of similar motions of different movement distances and velocities without recalculating system dynamics. Simulations based on human motions are reported that demonstrate the effectiveness of the proposed learning schemes in implementing this accuracy-simplification tradeoff.
Roles of additives in damascene copper electropolishing
(2006)
Liu, SH
;
Shieh, JM
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Chen, C
;
Hensen, K
;
Cheng, SS
This study explores how the dissolution of damascene Cu depends on accelerators of organic acids in alcohol-containing H3PO4 electropolishing electrolytes. Four two-additive electrolytes that contain different accelerators, acetic, citric, citrazinic, and benzoic acids, are evaluated. At the bottom of damascene features, an esterification reaction between alcohols and organic acids efficiently forms a highly resistive layer and reduces the acidity of the solution. Accordingly, outside the damascene features, the rate of removal of Cu is dominated by the acidity of electrolytes but, inside the features, it is also determined by the resistance of the viscous layer. For a weak acidic additive, acetic acid, an extremely high additive concentration is introduced to sustain the moderate acidity of the solution to initiate intense esterification. Therefore, acetic-acid-based two-additive electrolytes exhibit excellent Cu planarization capability. (C) 2006 The Electrochemical Society.
Study of electromigration in thin tin film using edge displacement method
(2005-07-01)
Yu, HC
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Liu, SH
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Chen, C
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材料科學與工程學系
;
Department of Materials Science and Engineering
Threshold current density and other electromigration parameters of pure. Sri films were measured using edge displacement method. Sn film with a thickness of 5000 A was evaporated on a 1200-angstrom-thick Ti film on a Si substrate. Electromigration behavior was investigated under the current densities of 2.5 X 10(4)-1.5 X 10(5) A/cm(2) at room temperature (RT 27-32 degrees C), 50, 75, and 100 degrees C. Both needle-type and hillock-type whiskers grew in the anode end when the films were stressed at RT and 50 degrees C, but only hillock-type whiskers were observed when they were stressed at 75 and 100 degrees C. The electromigration rate increased linearly with the applied current density for the four stressing temperatures. The threshold current density (J(c)) was measured to be 1.93 X 10(4) 9.65 X 10(3), 9.57 X 10(3), and 7.93 X 10(3) A/cm(2) for RT, 50, 75, and 100 degrees C, respectively. The measured activation energy was 0.32 eV. In addition, the measured critical length of the Sn film was 18 mu m at RT and the products of DZ* were 1.95 X 10(-10), 4.84 X 10(-10), 1.27 X 10(-9), and 1.99 X 10(-9) cm(2)/s for RT, 50, 75, and 100 degrees C, respectively. These results are fundamental to electromigration in Pb-free solders, since most of their matrices consist of almost pure Sri. 0 2005 American Institute of Physics.
Tin whisker growth driven by electrical currents
(2004-06-15)
Liu, SH
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Chen, C
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Liu, PC
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Chou, T
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材料科學與工程學系
Tin whisker growth was investigated in pure Sn using Blech structure. Blech structure was used to investigate the electromigration behavior in pure tin, in which 5000 Angstrom tin strips were on 700 Angstrom titanium films. Tin whiskers grew on the anode side, and voids were observed on the cathode side after stressing at the current densities of 7.5x10(4) and 1.5x10(5) A/cm(2) at room temperature. To investigate temperature effect, samples are stressed at room temperature and 50 degreesC. The whisker growth rates were estimated to be 3 and 7.7 Angstrom/s at room temperature and at 50 degreesC, respectively, in the current density of 1.5x10(5) A/cm(2). The whisker growth rate reduced to 0.4 Angstrom/s at the current density of 7.5x10(4) A/cm(2), which is still faster than that driven by mechanical stress. Transmission electron microscopy results showed that the whiskers are single crystalline and a thin Sn oxide formed on their surfaces. The mechanism of tin whisker growth driven by electrical force is proposed in this article. (C) 2004 American Institute of Physics.
Two-additive electrolytes for superplanarizing damascene Cu metals
(2005)
Liu, SH
;
Shieh, JM
;
Chen, C
;
Dai, BT
;
Hensen, K
Two-additive electropolishing (EP) electrolytes exhibit an extremely high planarization-efficiency in Cu damascene schemes, independent of pattern sizes (1- 50 mu m). This electrolyte is demonstrated by adding alcohols and organic acids to the H3PO4 electrolyte. The high wetting ability of alcohols allows such additives to easily access the damascene bottom. This mechanism, assisted by the reduced polishing rate associated with the high surface viscosity caused by alcohol additives, greatly passivates the damascene bottom from elecropolishing. Accordingly, the superpolishing functionality reported by Chang et al. [Electrochem. Solid-State Lett., 6, G72 (2003)] in the two-additive electrolyte outperforms in the one-additive electrolyte. (C) 2005 The Electrochemical Society.