Browsing by Author "Chiang, YC"

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Evaluation of PTFE nanoemulsion as a low dielectric constant material ILD
(1997)
Sun, SC
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Chiang, YC
;
Rosenmayer, CT
;
Teguh, J
;
Wu, H
Polytetrafluoroethylene (PTFE) has been studied as a low dielectric constant material for ULSI. A novel nanoparticle dispersion of PTFE was developed that permits the spin-coat deposition of PTFE with a thickness range of 0.2 to 1.5 mu m. These PTFE nanoemulsions are aqueous emulsions containing sub-50 nm size PTFE particles and surfactant that are thermodynamically stable, optically clear, and have low viscosity and surface tension. The films cast from this nanoemulsion are uniform in thickness with a standard deviation of < 2%. From FTIR spectra, significant amounts of C-F bonds (1153 cm(-1) and 1211 cm(-1)) are detected in the films. The index of refraction from ellipsometry measurement is about 1.35 and the dielectric constant measured from high frequency C-V curves is about 1.85. The dielectric strength is about 170 V/mu m. TGA data indicates a weight loss rate of less than 0.25%/hr. at 425 degrees C. The moisture absorption is less than 0.01%. After sintering, the films are extremely resistant to chemical attack by sulfuric acid, buffered HF, and positive photoresist developer. The etch rate in an oxygen plasma at 30 W is around 200 nm/min. Stud pull tests indicate good adhesion to SiO2, Al, and Cu. Results of thermal, dielectric, chemical, and adhesion tests indicate that these PTFE films have potential for use as an integrated circuit dielectric material.
Multivariate polynomial spline spaces
(1999-09-01)
Chen, LA
;
Hsu, YJ
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Chiang, YC
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應用數學系
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統計學研究所
In this paper we construct bases of certain spaces of multivariate polynomial splines defined on rectangular partitions. These bases are presented by polynomials, truncated power functions and products of these functions. This setting provides a natural generalization of the two-dimensional polynomial spline, proposed by Chui and Wang [3], to p variables.
Spectral and prosodic transformations of hearing-impaired Mandarin speech
(2006-02-01)
Lee, CL
;
Chang, WW
;
Chiang, YC
;
電信工程研究所
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Institute of Communications Engineering
This paper studies the combined use of spectral and prosodic conversions to enhance the hearing-impaired Mandarin speech. The analysis-synthesis system is based on a sinusoidal representation of the speech production mechanism. By taking advantage of the tone structure in Mandarin speech, pitch contours are orthogonally transformed and applied within the sinusoidal framework to perform pitch modification. Also proposed is a time-scale modification algorithm that finds accurate alignments between hearing-impaired and normal utterances. Using the alignments, spectral conversion is performed on subsyllabic acoustic units by a continuous probabilistic transform based on a Gaussian mixture model. Results of perceptual evaluation indicate that the proposed system greatly improves the intelligibility and the naturalness of hearing-impaired Mandarin speech. (c) 2005 Elsevier B.V. All rights reserved.