Browsing by Author "Chang, Wei-Yuan"

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Broadband UV-assisted thermal annealing of low-k silicon carbonitride films using a C-rich silazane precursor
(2018-11-01)
Chang, Wei-Yuan
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Chung, Hau-Ting
;
Chen, Yi-Chang
;
Leu, Jihperng
;
材料科學與工程學系
Low-k dielectric silicon carbonitride (SiCxNy) films are deposited by plasma-enhanced chemical vapor deposition using a carbon-rich silazane precursor, N-methyl-aza-2,2,4-trimethylsilacyclopentane (SiC7NH17), at 100 degrees C. The post-treatments of SiCxNy films are carried out by thermal annealing and a broadband UV-assisted thermal annealing (UV-annealing) at 400 degrees C for 5 min. Compared to the thermal annealing treatment, UV-annealing can improve both dielectric and mechanical properties of low-k SiCxNy films. Under thermal annealing, SiCxNy films show great thermal stability, but little structural change. In contrast, upon UV-annealing, most of the Si-H and N-H bonds are broken up, which induces more Si-N cross-linking and converts Si-C matrix into Si-N matrix. The ethylene bridges in Si-(CH2)(2)-Si also remain intact, but the unbridged hydrocarbons in Si-(CH2)(2)-N and Si-CH2-CH3 bonds decompose completely during the UV-annealing process. These account for the reduced dielectric constant to k = 3.2 from 3.6 and a 21% enhancement of Young's modulus to 7.4 GPa in the SiCxNy films after UV-annealing. Broadband UV-annealing shows promise as a post-treatment method for enhancing the properties of low-k dielectric barrier, SiCxNy films. Published by the AVS.
Effect of Moisture on Electrical and Reliability Characteristics for Dense and Porous Low-k Dielectrics
(2013-01-01)
Cheng, Yi-Lung
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Huang, Jun-Fu
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Chang, Wei-Yuan
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Chang, Yu-Min
;
Leu, Jihperng
The effect of absorbed moisture on the electrical and reliability characteristics of the low-k dielectrics was investigated in this study. The experimental results indicate that the porous low-k dielectrics would absorb more moisture as compared to the dense low-k dielectrics. This absorbed moisture degrades the electrical and reliability performance of the low-k dielectrics. A higher temperature anneals at 400 degrees C is needed to decompose physicallyadsorbed water, which is benefit to restore reliability performance. On the other hand, the chemically-adsorbed moisture seems to be difficult to be removed by a 400 degrees C annealing, causing a degraded TDDB performance.
Effect of moisture on electrical properties and reliability of low dielectric constant materials
(2014-02-01)
Cheng, Yi-Lung
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Leon, Ka-Wai
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Huang, Jun-Fu
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Chang, Wei-Yuan
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Chang, Yu-Min
The effect of absorbed moisture on the electrical characteristics and reliability of low dielectric constant materials (low-k) was investigated in this study. The experimental results reveal that porous low-k dielectrics absorb more moisture than dense low-k dielectrics. This absorbed moisture degrades the electrical performance and reliability of both classes of low-k dielectrics. Annealing at a higher temperature of 400 degrees C is required to decompose the physically-adsorbed moisture and thereby restore reliability performance. However, the chemically-adsorbed moisture seems to be difficult to remove by annealing at 400 degrees C, causing a degraded TDDB performance. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.
Effect of NH3/N-2 ratio in plasma treatment on porous low dielectric constant SiCOH materials
(2014-05-01)
Huang, Jun-Fu
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Bo, Tain-Cih
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Chang, Wei-Yuan
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Chang, Yu-Min
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Leu, Jihperng
This study investigates the effect of the NH3/N-2 ratio in plasma treatment on the physical and electrical properties as well as the reliability characteristics of porous low-k films. All of the plasma treatments resulted in the formation of a thin and modified layer on the surface of porous low-k films, and the properties of this modified layer were influenced by the NH3/N-2 ratio in the plasma. Experimental results indicated that pure N-2 gas plasma treatment formed an amide-like/nitride-like layer on the surface, which apparently leads to a higher increase in the dielectric constant. Plasma treatment with a mixture of NH3/N-2 gas induced more moisture uptake on the surface of the low-k dielectric, degrading the electrical performance and reliability. Among all plasma treatment with NH3/N-2 mixed gas, that with pure NH3 gas yielded low-k dielectrics with the worse electrical and reliability characteristics. (C) 2014 American Vacuum Society.
Effect of thermal treatment on physical, electrical properties and reliability of porogen-containing and porogen-free ultralow-k dielectrics
(2013-01-15)
Chang, Yu-Min
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Chang, Wei-Yuan
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Huang, Jun-Fu
;
Leu, Jihperng
;
Cheng, Yi-Lung
The effects of thermal annealing on the physical, electrical properties and reliability of porogen-containing and porogen-free ultralow-k dielectrics prepared by plasma-enhanced chemical vapor deposition (PECVD) are investigated. The porogen-free low-k dielectrics are obtained by using UV curing process to removal organic sacrificial phase and to generate open porosity. The results are compared with PECVD porogen-containing low-k films fabricated without UV curing process and PECVD low-k dielectrics deposited without organic sacrificial phase. The experimental results show that all low-k films remained stable after they were experimentally heating to temperatures up to 700 degrees C. The non-porous low-k films also showed the highest reliability. Although the porous-free low-k film requires an additional UV curing process, the heat stress confirmed that its thermal stability was better than that of the porogen-containing low-k film. At an annealing temperature above 500 degrees C, the heating process is comparable to UV curing, but does not provide Si-O-Si cross-linking within the film. At an annealing of 600 degrees C, the porogen-free low-k films have a relatively higher breakdown electric-field and longer failure time in comparison to the porogen-containing low-k films. However, pores generated in porogen-containing low-k films at high temperature cause reliability to degrade with annealing temperature. Crown Copyright (c) 2012 Published by Elsevier B.V. All rights reserved.
Effect of UV curing time on physical and electrical properties and reliability of low dielectric constant materials
(2014-11-01)
Kao, Kai-Chieh
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Chang, Wei-Yuan
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Chang, Yu-Min
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Leu, Jihperng
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Cheng, Yi-Lung
This study comprehensively investigates the effect of ultraviolet (UV) curing time on the physical, electrical, and reliability characteristics of porous low-k materials. Following UV irradiation for various periods, the depth profiles of the chemical composition in the low-k dielectrics were homogeneous. Initially, the UV curing process preferentially removed porogen-related CHx groups and then modified Si-CH3 and cage Si-O bonds to form network Si-O bonds. The lowest dielectric constant (k value) was thus obtained at a UV curing time of 300 s. Additionally, UV irradiation made porogen-based low-k materials hydrophobic and to an extent that increased with UV curing time. With a short curing time (<300 s), porogen was not completely removed and the residues degraded reliability performance. A long curing time (>300 s) was associated with improved mechanical strength, electrical performance, and reliability of the low-k materials, but none of these increased linearly with UV curing time. Therefore, UV curing is necessary, but the process time must be optimized for porous low-k materials on back-end of line integration in 45 nm or below technology nodes. (C) 2014 American Vacuum Society.
Embedded carbon bridges in low-k PECVD silicon carbonitride films using silazane precursors
(2019-07-01)
Chang, Wei-Yuan
;
Chen, Wei-Zhong
;
Lee, Hung-Tse
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Leu, Jihperng
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材料科學與工程學系
Low-k, carbon-rich SiCxNy films for diffusion barrier applications have been fabricated by plasma-enhanced chemical vapor deposition (PECVD) using silazanes as the single-source precursor. Linear and cyclic silazane precursors with vinyl groups yield SiCxNy films with carbon bridges, namely ethylene bridges (Si-CH2-CH2-Si) and methylene bridges (Si-CH2-Si), which are readily formed and embedded with the Si-N(-C) matrix. A SiCxNy film of low k = 3.2 is achieved by successful incorporation of ethylene bridge embedded within the Si-N(-C-x) network by using a linear silazane precursor. Also, for these silazanes-deposited SiCxNy films at a fixed dielectric constant below 4.2, cyclic silazane, VSZ (1,3,5-trimethyl-1,3,5-trivinylcyclotrisilazane) produces films of higher film density and modulus, compared to those by a linear silazane precursor. (C) 2019 The Japan Society of Applied Physics
Modeling Transaction Costs and Skewness in Portfolio: Application of Fuzzy Approach
(2013)
Yu, Jing-Rung
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Chiou, Wan-Jiun Paul
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Chang, Wei-Yuan
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Lee, Wen-Yi
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科技管理研究所
How to deal with errors in estimating return and trading costs is a critical issue in portfolio management. In this paper, we investigate the over-time rebalancing benefits of the portfolio models that consider mean, variance, skewness, allowing short-sale, and transaction costs by incorporating fuzzy decision making. We apply multiple criterion method to deal with the complexity of various objectives. Our empirical results using 144 stocks in Taiwan Stock Exchange confirm the benefits of fuzzy decision making with inclusion of higher moment risk, skewness, in portfolio model, particularly when short-sale is allowed.
Optical properties of plasma-enhanced chemical vapor deposited SiCxNy films by using silazane precursors
(2017-08-31)
Chang, Wei-Yuan
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Chang, Chieh-Yu
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Leu, Jihperng
;
材料科學與工程學系
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Department of Materials Science and Engineering
In this study, amorphous silicon carbonitride (SiCxNy) films were fabricated by radio frequency (RF) chemical vapor deposition (PECVD) using a single silazane precursor and a low power density (0.15W/cm(3)) for better compositional control. The effects of the precursor chemical structure (C/Si ratio, C-Si-N structure, and vinyl groups) and deposition temperature (T-s) on the chemical structure and optical properties of SiCxNy films were examined using Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. Specifically, two new single precursors; namely, n-methyl-aza-2,2,4-trimethylsilacyclopentane (MTSCP) and 1,3-divinyl-1,1,3,3-tetramethyl-disilazane (DVTMDS) were studied and compared. SiCxNy films deposited using MTSCP involving Si-C-3-N rings formed Si-N and Si-(CH2)(3)-crosslinked structures at T-s <= 100 degrees C, and were then changed to predominantly Si-CH2-N-Si crosslinked structures at Ts > 300 degrees C, leading to a wide range of optical band gap from 5.2 to 3.7 eV. Compared to DVTMDS-deposited SiCxNy films, their relatively higher percentage of Si-C-N structure accounted for the lower optical band gap and reduced transmission. DVTMDS with di-vinyl groups readily formed a Si-(CH2)(2)-bridge in SiCxNy films Ts <= 200 degrees C, resulting in excellent optical transmittance. The transmittance in the visible wavelengths of 400 degrees C-deposited SiCxNy film using DVTMDS still showed 85%. Also, tunable refractive index between 1.44 and 2.10 were obtained for SiCxNy films deposited at T-s <= 400 degrees C. (c) 2017 Elsevier B.V. All rights reserved.