Browsing by Author "Wang, MT"

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A versatile QCM matrix system for online and high-throughput bio-sensing
(2006)
Huang, GS
;
Wang, MT
;
Hong, MY
;
材料科學與工程學系奈米科技碩博班
;
Graduate Program of Nanotechnology , Department of Materials Science and Engineering
A 3 x 3 quartz crystal microbalance (QCM) sensor matrix, fabricated on an A-T cut quartz crystal, has the ability to detect online a variety of labeled DNA samples in a parallel and comparative fashion. The QCM matrix was equipped with a single oscillator circuit, which activated only one QCM at any given time, and was controlled by programmable time-shared electronic relays. The gold electrode had a diameter of 0.8 mm and operated at a fundamental resonating frequency of 40MHz; the dimensions of the matrix were 1.2 cm x 1.2 cm. The sensitivity of an individual QCM was in the pictogram regime. Selected QCMs were coated with either streptavidin or the anti-DIG antibody; the specificity of their detections was monitored using various concentrations of samples of biotin- and DIG-labeled DNA. The basic design of the QCM matrix is readily expandable, without any conceivable difficulties, in both geometry and circuitry.
Barrier capabilities of selective chemical vapor deposited W films and WSiN/WSix/W stacked layers against Cu diffusion
(1999-02-01)
Wang, MT
;
Chen, LJ
;
Chen, MC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This work investigates the barrier capability of W layers as well as WSiN/WSix/W stacked layers against Cu diffusion. The VV layers were selectively chemical vapor deposited (CVD) in contact holes to a thickness of about 450 nm using SiH4 reduction of WF6. We found that the CVD-W layers functioned as effective barriers against Cu diffusion, and the Cu/W(450 nm)/p(+)-n junction diodes were able to sustain a 30 min furnace annealing up to 650 degrees C without causing degradation in electrical characteristics. The use of WSiN/WSix/W stacked layers as diffusion layers further improved the thermal stability of Cu/WSiN/WSix/W(450 nm)p(+)-n junction diodes to at least 700 degrees C. The WSix layers were deposited by CVD to a thickness of 75 nm using SiH4/WF6 chemistry, and the subsequent in situ N-2 plasma treatment produced a very thin layer of WSiN on the WSix surface. This thin WSiN layer was very thermally stable and effective in suppressing Cu diffusion, failure of barrier capability for the W films was presumably due to interdiffusion of Cu and Si along grain boundaries of the W films, and the interdiffusion was probably enhanced by the formation of WSi2, The formation of WS(i)2 consumed the W layer and Si substrate, resulting in a volume change in barrier layer, which, in turn, developed local defects, such as microcracks and stress-induced weak points, and thus provided fast paths for Cu diffusion. (C) 1999 The Electrochemical Socity S0013-4651(98)04-036-1. All rights reserved.
Barrier properties of very thin Ta and TaN layers against copper diffusion
(1998-07-01)
Wang, MT
;
Lin, YC
;
Chen, MC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Diffusion barrier properties of very thin sputtered Ta and reactively sputtered TaN films used as a barrier layer between Cu and Si substrates were investigated using electrical measurement and materials analysis. The Cu/Ta/p(+)-n junction diodes with the Ta barrier of 5, 10, and 25 nm thicknesses were able to sustain a 30 min thermal annealing at temperatures up to 450, 500, and 550 degrees C, respectively, without causing degradation to the device's electrical characteristics. The barrier capability of Ta layer can be effectively improved by incorporation of nitrogen in the Ta film using reactive sputtering technique. For the Cu/TaN/p(+)-n junction diodes with the TaN barrier of 5,10, and 25 nm thicknesses, thermal stability was able to reach 500, 600, and 700 degrees C, respectively. We found that failure of the very thin Ta and TaN barriers was not related to Ta silicidation at the barrier/Si interface. Failure of the barrier layer is presumably due to Cu diffusion through the barrier layer during the process of thermal annealing via local defects, such as grain boundaries and stress-induced weak points.
Chemical mechanical polishing for selective CVD-W
Wang, MT
;
Yeh, WK
;
Tsai, MS
;
Tseng, WT
;
Chang, TC
This work investigates chemical mechanical polishing (CMP) for W-filled contact holes, vias, and trenches by selective chemical vapor deposition. A novel process that combines the CMP technique with selective chemical vapor deposition of tungsten (CVD-W) was employed to remove nail heads due to overgrowth and W-particles on the surface of dielectric due to selectivity loss. The overfilled nail heads and the selectivity loss can be completely removed with very low down-pressure (3 psi) in a very short polishing time (30 s). This indicates that the novel process is very promising for ULSI multilevel interconnection application. The removal rate selectivities of W to thermal oxide, PECVD-TEOS, and BPSG were found to be 47:1, 30:1 and 15:1, respectively, while the selectivities of W to the barrier metals of TiW, Ti and Ta were determined to be 0.6:1, 6:1 and 28:1, respectively. (C) 1997 Elsevier Science S.A.
Chemical mechanical polishing for selective CVD-W
Wang, MT
;
Yeh, WK
;
Tsai, MS
;
Tseng, WT
;
Chang, TC
This work investigates chemical mechanical polishing (CMP) for W-filled contact holes, vias, and trenches by selective chemical vapor deposition. A novel process that combines the CMP technique with selective chemical vapor deposition of tungsten (CVD-W) was employed to remove nail heads due to overgrowth and W-particles on the surface of dielectric due to selectivity loss. The overfilled nail heads and the selectivity loss can be completely removed with very low down-pressure (3 psi) in a very short polishing time (30 s). This indicates that the novel process is very promising for ULSI multilevel interconnection application. The removal rate selectivities of W to thermal oxide, PECVD-TEOS, and BPSG were found to be 47:1, 30:1 and 15:1, respectively, while the selectivities of W to the barrier metals of TiW, Ti and Ta were determined to be 0.6:1, 6:1 and 28:1, respectively. (C) 1997 Elsevier Science S.A.
Chemical mechanical polishing for selective CVD-W
(1997-10-30)
Wang, MT
;
Yeh, WK
;
Tsai, MS
;
Tseng, WT
;
Chang, TC
This work investigates chemical mechanical polishing (CMP) for W-filled contact holes, vias, and trenches by selective chemical vapor deposition. A novel process that combines the CMP technique with selective chemical vapor deposition of tungsten (CVD-W) was employed to remove nail heads due to overgrowth and W-particles on the surface of dielectric due to selectivity loss. The overfilled nail heads and the selectivity loss can be completely removed with very low down-pressure (3 psi) in a very short polishing time (30 s). This indicates that the novel process is very promising for ULSI multilevel interconnection application. The removal rate selectivities of W to thermal oxide, PECVD-TEOS, and BPSG were found to be 47:1, 30:1 and 15:1, respectively, while the selectivities of W to the barrier metals of TiW, Ti and Ta were determined to be 0.6:1, 6:1 and 28:1, respectively. (C) 1997 Elsevier Science S.A.
Chemical mechanical polishing for selective CVD-W
(1997-10-30)
Wang, MT
;
Yeh, WK
;
Tsai, MS
;
Tseng, WT
;
Chang, TC
This work investigates chemical mechanical polishing (CMP) for W-filled contact holes, vias, and trenches by selective chemical vapor deposition. A novel process that combines the CMP technique with selective chemical vapor deposition of tungsten (CVD-W) was employed to remove nail heads due to overgrowth and W-particles on the surface of dielectric due to selectivity loss. The overfilled nail heads and the selectivity loss can be completely removed with very low down-pressure (3 psi) in a very short polishing time (30 s). This indicates that the novel process is very promising for ULSI multilevel interconnection application. The removal rate selectivities of W to thermal oxide, PECVD-TEOS, and BPSG were found to be 47:1, 30:1 and 15:1, respectively, while the selectivities of W to the barrier metals of TiW, Ti and Ta were determined to be 0.6:1, 6:1 and 28:1, respectively. (C) 1997 Elsevier Science S.A.
Development and deployment of public transport policy and planning in Taiwan
(2006-03-01)
Lan, LW
;
Wang, MT
;
Kuo, AY
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
Over the past decade, the escalating roadway congestion and environmental deterioration due to heavy use of private vehicles have provoked the Taiwan government to realize the importance of public transport systems. Under the "carrot-and-stick" rationales, the government has formulated public transport policies and exercised a series of related initiatives by providing sufficient and higher quality of public transport services so as to attract more private vehicle users. In this paper, the planning philosophy and policy formulation of Taiwan's public transport development are highlighted. The most important initiatives, including the Five-year Enhancement of Mass Transportation Program and the upgrading public transport schemes in the National Development Plan are examined. Based on previous experience and lessons, we point out the most challenging issues that the government will encounter. Suggestions for the future of public transport planning are also addressed.
Effective improvement on barrier capability of chemical vapor deposited WSix using N-2 plasma treatment
(1999-04-01)
Wang, MT
;
Lin, YC
;
Wang, CC
;
Chen, MC
;
電子工程學系及電子研究所
This work studies the thermal stability of Cu/WSx/p(+)-n and Cu/WSiN/WSix/p(+)-n diodes in which the WSix barrier layers were deposited by chemical vapor deposition to a thickness of about 50 nm using SiH4/WF6 chemistry with the SiH4/WF6 flow rates of 6/2 seem, while the WSiN layers were formed by in situ N-2 plasma treatment on the chemically vapor deposited WSix (CVD-WSix) surfaces. Without N-2 plasma treatment, the thermal stability of Cu/WSix (50 nm)/p(+)-n junction diodes was found to reach 500 degrees C; with N-2 plasma treatment, the resultant Cu/WSiN/WSix (50 nm)/p(+)-n junction diodes were able to retain integrity of electrical characteristics up to at least 600 degrees C. Failure mechanism of the WSiN/WSix bilayer in the Cu/WSiN/WSix/Si structure was closely related to the WSix/Si interface reaction and the tungsten silicide formation of the WSix layer. Thus, barrier capability of the WSiN/WSix bilayer can be further improved by suppressing the WSix/Si interface reaction and the silicidation of the WSix layer. The thermal stability of Cu/barrier/p(+)-n diodes was further raised to 650 degrees C by using a multilayer barrier structure of WSiN/Si-x (50 nm)/WSiN/WSix (10 nm) or a WSiN/WSiy (y > 1) barrier We conclude that the post-CVD-WSix treatment with in situ N-2 plasma is a simple, practical, and efficient method of improving the WSix-based barrier capability for Cu metallization. (C) 1999 The Electrochemical Society. S0013-4651(97)09-073-9. All rights reserved.
Effects of composition and N-2 plasma treatment on the barrier effectiveness of chemically vapor deposited WSix films
(2000-07-01)
Wang, MT
;
Chuang, MH
;
Chen, LJ
;
Chen, MC
;
電子工程學系及電子研究所
This work investigates the thermal stability of chemically vapor deposited amorphous WSix layers used as a diffusion barrier between Cu and Si substrate, in which the WSix layers were deposited to a thickness of about 50 nm using the SiH4 reduction of WF6 at various SiH4/WF6 how ratios. For 30 min annealing in nitrogen ambient, the effectiveness of the WSix layers as barriers between a copper overlayer and a p(+) -n junction diode decreases as the Si/W atomic ratio, x, increasing from 1 to 1.3. This composition change is obtained by raising the SiH4/WF6 flow ratio from 3 to 50. As deposited, all films are x-ray amorphous. Their resistivity increases roughly linearly with x. The barrier capability of WSix layers can be significantly improved by an in situ N-2 plasma treatment. The N-2 plasma treatment produces a very thin layer of WSiN (about 5 nm) on the surfaces of WSix layers. In particular, the Cu/WSiN/WSix/ p(+) -n junction diodes with the WSix layers deposited with a SiH4/WF6 flow ratio of 3 were able to remain intact up to at least 600 degrees C. (C) 2000 American Vacuum Society. [S0734-211X(00)03204-2].
Effects of corrosion environments on the surface finishing of copper chemical mechanical polishing
(1997-10-31)
Wang, MT
;
Tsai, MS
;
Liu, C
;
Tseng, WT
;
Chang, TC
Copper chemical mechanical polishing (Cu-CMP) was investigated using slurries containing alumina abrasive and various types and concentrations of oxidizer, as well as benezotriazole (BTA) additive. We found that the corrosion rate of copper film decreases with increasing BTA concentration in 3 vol.% HNO3 solution, but the passivation effect of BTA saturates as the concentration reaches about 0.01 M. On the other hand, a small amount of H2O2 in H2O2/XJFW8099 slurry enhances the corrosion rate dramatically, while abundance of H2O2 in the slurry suppresses the corrosion reaction effectively. The polishing rate and its non-uniformity decrease with increasing volume ratio of H2O2 in H2O2/XJEW8099 slurry. A very smooth surface with a removal rate of 363.0 nm/min was obtained using the slurry of 1/1 ratio. Depletion of H2O2 in the slurry can result in more abrasive residuals as well as a rougher surface; the surface roughness increases from 0.3 to 9.9 nm as the H2O2/XJFW8099 ratio decreases from 1/1 to 1/4. Our results indicate that the corrosion rate, polishing rate and surface roughness of copper films are sensitively dependent on the type and concentration of oxidizer as well as the BTA additive. (C) 1997 Elsevier Science S.A.
Investigation of programmed charge lateral spread in a two-bit storage nitride flash memory cell by using a charge pumping technique
(2004)
Gu, SH
;
Wang, MT
;
Chan, CT
;
Zous, NK
;
Yeh, CC
The lateral distribution of programmed charge in a hot electron program/hot hole erase nitride storage flash cell is investigated by using a charge pumping technique. Our study shows that the secondly programmed bit has a wider trapped charge distribution than the first programmed bit. In addition, we find prograrnmed charge spreads further into the channel with program/erase cycle number.
Properties and thermal stability of chemically vapor deposited W-rich WSix thin films
(1999-03-01)
Wang, MT
;
Lin, YC
;
Chuang, MS
;
Chun, MC
;
Chen, LJ
The tungsten-rich (Si/W atomic ratio less than 2.0) chemical vapor deposition (CVD)-WSix layer was found to be an efficient diffusion barrier against Cu diffusion. In this study, the properties and thermal stability of the W-rich WSix films chemically vapor deposited at various deposition temperatures, pressures, and SiH4/WF6 reactant gas flow ratios were investigated. With SiH4/WF6 flow rates of 6/2 seem and a total gas pressure of 12 mTorr, the activation energy of the CVD process was determined to be 3.0 kcal/mole, and the film deposited at 250 degrees C has a Si/W atomic ratio of unity. The WSix, films have a low residual stress, low electrical resistivity, and excellent step coverage. For the WSix layers deposited on Si substrates, the residual stress varies from 7 to 9 X 10(8) dynes/cm(2) depending on the deposition temperature. The resistivity of the WSI, films varies from 200 to 340 mu Omega cm; higher deposition temperatures and SiH4/WF6 flow ratios resulted in higher film resistivities. The as-deposited amorphous WSix layer is thermally stable up to 600 degrees C; however, crystallization of the deposited film takes place at 650 degrees C and WSix was transformed into WSi2 phase when the WSix/Si structure was thermally annealed at temperatures above 650 degrees C. (C) 1999 American Vacuum Society. [S0734-211X(99)03602-1].
Stress migration and electromigration improvement for copper dual damascene interconnection
(2005)
Wang, TC
;
Hsieh, TE
;
Wang, MT
;
Su, DS
;
Chang, CH
Stress migration (SM) and electromigration (EM) were widely used to study the performance of interconnection process of metal/via formation in copper dual damascene of wafers. Necking and voids at the via bottom were important in causing failures in tests of stress migration and electromigration. In this report, the contamination of the bottom of via, which results in poor step coverage, the adhesion of seed layers, and poor copper grain formation are identified to be the underlying causes of the necking and void formation after the first EM and SM tests are performed. The contamination of the via formation processes included via etching, trench etching, and barrier/seed layer depositions. A well-shaped via profile can be optimized using three methods, the first involves Cu/SiN interface stress, the second involves Cu grain growth, and the third involves post via etching clean study. Eliminating the contamination of the via bottom and optimizing step coverage and adhesion of the barrier seed layers improve the EM and SM performance from time-to-fail = 13 to 59 s, in the copper-related processes for fabricating 300 mm wafers using technology that is beyond 0.13 mm technology. (C) 2004 The Electrochemical Society.
Thermal stability of selective chemical vapor deposited tungsten contact and effects of in situ N-2 plasma treatment
(1998-07-01)
Wang, MT
;
Wang, PC
;
Chuang, MC
;
Chen, LJ
;
Chen, MC
This work investigates the thermal stability of Al/W/p(+)-n junction diodes, in which the W contact was filled using selective chemical vapor deposition to a thickness of about 450 nm and served as diffusion barrier between the Al and the Si substrate. The effects of in situ N-2 plasma treatment on the barrier effectiveness were also investigated. The Al/W(450 nm)/p(+)-n junction diodes can sustain a 30 min furnace annealing up to 575 degrees C. With an in situ N-2 plasma treatment on the W surface caused a thin layer of WNx to form on the W surface, and the nitrified layer of WNx/W acting as barrier between the AZ and the Si substrate effectively suppressed WAl12 formation at elevated temperatures, resulting in a significant barrier improvement. N2 plasma treatment at 100 W for 300 s enabled the Al/WNx/W(450 nm)lp(+)-n junction diodes to sustain thermal annealing at temperatures up to 625 degrees C without degradation of electrical characteristics. (C) 1998 American Vacuum Society.
Thin-film properties and barrier effectiveness of chemically vapor deposited amorphous WSix film
(1998-12-01)
Wang, MT
;
Lin, YC
;
Lee, JY
;
Wang, CC
;
Chen, MC
Thin-Film properties and barrier effectiveness against copper (Cu) diffusion of a thin amorphous WSix layer were investigated. The amorphous WSix layer was deposited by the chemical vapor deposition (CVD) method using the SiH4/WF6 chemistry with the activation energy determined to be 3.0 kcal/mol. The CVD-WSix film has a low film stress, low electrical resistivity, and excellent step coverage. The resistivity of the amorphous CVD-WSix layer increases with the deposition temperature, but the residual stress of the layer decreases with the deposition temperature. The WSix/Si structure is thermally stable up to at least 600 degrees C, while the copper-contacted Cu/WSix/Si structure with a 50 nm thick WSix barrier is stable only up to 550 degrees C. Moreover, the Cu/WSix/p(4)-n junction diodes can sustain a 30 min thermal annealing up to 500 degrees C without causing degradation in electrical characteristics. Barrier failure of the WSix layer in the Cu/WSix/Si structure at temperatures above 550 degrees C is attributed to Cu atoms diffusion via fast paths in the WSix layer. These fast paths were presumably developed from grain growth of the WSix layer and/or thermal-stress-induced weak points in the WSix layer.