Browsing by Author "Tsai, MS"

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A study on electrochemical metrologies for evaluating the removal selectivity of AlCMP
(1999)
Chiu, SY
;
Hsu, JW
;
Tung, IC
;
Shih, HC
;
Feng, MS
The in-situ electrochemical measurements were performed for the Al and Ti disks in the various slurries under the polishing or static condition. The slurries used contained Al2O3 abrasive, phosphoric acid, citric acid and hydrogen peroxide. The results showed that the addition of H2O2 could help to form an effective passivating layer on the Al surface. Besides, the addition of H2O2 enhanced Al dissolution. The maximum corrosion potential drop between the abraded and non-abraded Al electrodes corresponded to the possible maximum polishing rate of Al. The novel equipment for in-situ galvanic measurements was designed for evaluating the Al/Ti galvanic couple. It was found that Al dissolution could be suppressed in the slurry with the addition of 6 vol% H2O2 at pH 4. As regards the Al/Ti removal selectivity, the polishing with the addition of 6 vol% H2O2 at pH 4 would mitigate the Al dishing, since the polishing and dissolution of Al could be suppressed while those of Ti could be enhanced.
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.
Chemical-mechanical polishing and material characteristics of plasma-enhanced chemically vapor deposited fluorinated oxide thin films
(1997-03-01)
Tseng, WT
;
Hsieh, YT
;
Lin, CF
;
Tsai, MS
;
Feng, MS
The chemical-mechanical polishing (CMP) process has been proven to be the most promising method for accomplishing global planarization. In this paper, results of chemical-mechanical polishing of fluorinated silicon dioxide (SiOF) thin films are presented. Nanohardness, elastic modulus, and bonding structure of fluorinated silicon dioxides are characterized in order to evaluate their correlations with CMP performance. The results show that under fixed chemistry and mechanical parameters, the CMP removal rate increases significantly with increasing fluorine content in the oxides due to the lower hardness and elastic modulus in the films. Higher CMP removal rate is observed for fluorinated oxides polished with slurry of pH 10 relative to pH 9. Compared with undoped oxides, SiOF films are more sentisitive to chemical and moisture attacks as reflected by the post-CMP increase in refractive index.
Chemical-mechanical polishing of low-dielectric-constant spin-on-glasses: film chemistries, slurry formulation and polish selectivity
(1997-10-31)
Wang, YL
;
Liu, C
;
Chang, ST
;
Tsai, MS
;
Feng, MS
Alkyl siloxane-based low-dielectric-constant (low-k) spin-on-glass (SOG) thin films with varying amounts of organic content were subjected to polishing experiments using silica-and ZrO2-based slurries with a variety of additives, As the amount of organic content in SOG increases, the chemical-mechanical polishing (CMP) removal rate decreases with silica-based potassium hydroxide-added slurry. On the other hand, zirconia-based slurry resulted in higher removal rates for both SOG (>400 nm/min) and thermal oxide and an adjustment in polish selectivity (related to thermal oxide) ranging from 1.2 to 9.1 can be achieved by adding various amounts of tetra-alkyl substituted ammonium hydroxide. Post-CMP materials characterization by Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM) shows the chemical stability and CMP compatibility of SOG thin films. (C) 1997 Elsevier Science S.A.
Conduction mechanism and temperature-dependent current-voltage in (Ba, Sr)TiO3 thin films
(1998-08-01)
Tsai, MS
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
RF magnetron sputtered (Ba, Sr)TiO3 (BST) thin films were deposited on Pt/SiO substrate with various O-2/(O-2 + Ar) mixing ratios (OMR) ranging from 0 to 60%. Two possible conduction mechanisms of the BST thin films, the Poole-Frenkel (PF) transport (bulk limited conduction) and the Schottky emission (SE) (electrode limited conduction) were studied. Experimental results indicated that the BST films prepared at low OMR (0-25%) exhibit the SE mechanism dominated below the transition electric field of 490 kV/cm and the PF transport mechanism dominated beyond 490 kV/cm; and while those prepared at high OMR (40-60%) display the SE mechanism dominated both below and beyond the transition electric field. The difference in dominant mechanism (bulk and electrode limited conduction) between films was ascribed to concentration variation of the oxygen vacancy in the films.
Dielectric relaxation and defect analysis of Ta2O5 thin films
(2000-05-21)
Ezhilvalavan, S
;
Tsai, MS
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The presence of defects in thin-film dielectrics often leads to dielectric relaxation as a function of frequency, in which the dielectric constant decreases and the loss tangent increases with increasing frequency. Dielectric relaxation results in charge storage capacity reduction under dynamic random access memory operating conditions. In this work, the dielectric relaxation behaviour of de reactive sputtered Ta2O5 thin film was investigated. Using dielectric dispersion measurements as a function of frequency (100 Hz less than or equal to f less than or equal to 10 MHz) and temperature (27 degrees C less than or equal to T less than or equal to 150 degrees C), we determined the dielectric relaxation and defect quantity of the films and propose an equivalent circuit on the basis of complex capacitance, admittance and impedance spectral studies.
Effect of bottom electrode materials and annealing treatments on the electrical characteristics of Ba0.47Sr0.53TiO3 film capacitors
(1999-02-01)
Tsai, MS
;
Sun, SC
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The dielectric constant and leakage current density of Ba0.47Sr0.53TiO3 (BST) thin films deposited by radiofrequency magnetron sputtering on various bottom electrode materials (Pt, Ir, IrO2/Ir, Ru, RuO2/Ru) before and after annealing in O-2 and N-2 ambient were investigated. Improvement in crystallinity of BST films deposited on various bottom electrodes was observed with annealing. The refractive index, dielectric constant, loss tangent, and leakage current of the films were also strongly dependent on annealing conditions. A BST thin film deposited on an Ir bottom electrode at 500 degrees C, after 700 degrees C annealing in O-2 for 20 min, had a dielectric constant of 593 +/- 5%, a loss tangent of 0.019 +/- 10% at 100 kHz, a leakage current of (2.1 +/- 13%) x 10(-8) A/cm(2) at an electric field of 100 kV/cm with a delay time of 30 s, and a charge storage density of 53 +/- 5% fC/mu m(2) at an applied field of 150 kV/cm. Based on the dielectric constant, leakage current, and reliability, the optimum material for the bottom electrode with annealing was Ir, Interdiffusion of Ru and Ti at the interface between the BST film and Ru electrode was observed in 500 degrees-700 degrees C annealed samples. The 10 year lifetime of time-dependent dielectric breakdown (TDDB) studies indicated that BST on Pt, Ir, IrO2/Ir, Ru, and RuO2/Ru had long lifetime over 10 years of operation at a voltage bias of 1 V.
Effect of bottom electrode materials on the electrical and reliability characteristics of (Ba, Sr)TiO3 capacitors
(1999-09-01)
Tsai, MS
;
Sun, SC
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The dielectric constant and the leakage current density of (Ba, Sr)TiO3 (BST) thin films deposited on various bottom electrode materials (Pt, Ir. IrO2/Ir, Ru, RuO2/Ru) before and after annealing in O-2 ambient were investigated. The improvement of crystallinity of BST films deposited on various bottom electrodes was observed after the postannealing process, The dielectric constant and leakage current of the films were also strongly dependent on the postannealing conditions. BST thin film deposited on Ir bottom electrode at 500 degrees C, after 700 degrees C annealing in O-2 for 20 min, has the dielectric constant of 593, a loss tangent of 0.019 at 100 kHz, a leakage current density of 1.9 x 10(-8) A/cm(2) at an electric field of 200 kV/cm with a delay time of 30 s, and a charge storage density of 53 fC/mu m(2) at an applied field of 100 kV/cm, The BST films deposited on Ir with post-annealing can obtain better dielectric properties than on other bottom electrodes in our experiments, And Ru electrode is unstable because the interdiffusion of Ru and Ti occurs at the interface between the BST and Ru after postannealing. The ten-year lifetime of time-dependent dielectric breakdown (TDDB) studies indicate that BST on Pt, Ir, IrO2/Ir, Ru, and RuO2/Ru have long lifetimes over ten years on operation at the voltage bias of 2 V.
Effect of bottom electrodes on dielectric relaxation and defect analysis of (Ba0.47Sr0.53)TiO3 thin film capacitors
(1998-11-01)
Tsai, MS
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The dielectric relaxation and defect analysis of (Ba0.47Sr0.53)TiO3 (BST) thin films deposited on various bottom electrodes, such as Pt, Ir, IrO2/Ir, Ru, RuO2/Ru before and after annealing in O-2 ambient was investigated. Through the measurement of dielectric dispersion as a function of frequency (100 Hz less than or equal to f less than or equal to 10 MHz) and temperature (27 degrees C less than or equal to T less than or equal to 150 degrees C), we studied the trapping dielectric relaxation and defect quantity of the films, and proposed an equivalent circuit on the basis of the capacitance, admittance and impedance spectra. A shallow trap level located at 0.005-0.01 eV below the conduction band was observed from the admittance spectral studies in the temperature range of 27-150 degrees C. The origin of dielectric relaxation and defect concentration was attributed to the existence of the grain boundary defect, interface defect and shallow trap level in the films. An equivalent circuit was established which can well explain the AC response and identify the contribution of defects on electrical properties of BST thin film. From the viewpoint of trapping phenomena and dielectric relaxation analyses, we propose Ir as the optimum material for bottom electrode to withstand the post-annealing treatment. (C) 1998 Elsevier Science S.A. All rights reserved.
Effect of bottom electrodes on dielectric relaxation and defect analysis of (Ba0.47Sr0.53)TiO3 thin film capacitors
(1998-11-01)
Tsai, MS
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The dielectric relaxation and defect analysis of (Ba0.47Sr0.53)TiO3 (BST) thin films deposited on various bottom electrodes, such as Pt, Ir, IrO2/Ir, Ru, RuO2/Ru before and after annealing in O-2 ambient was investigated. Through the measurement of dielectric dispersion as a function of frequency (100 Hz less than or equal to f less than or equal to 10 MHz) and temperature (27 degrees C less than or equal to T less than or equal to 150 degrees C), we studied the trapping dielectric relaxation and defect quantity of the films, and proposed an equivalent circuit on the basis of the capacitance, admittance and impedance spectra. A shallow trap level located at 0.005-0.01 eV below the conduction band was observed from the admittance spectral studies in the temperature range of 27-150 degrees C. The origin of dielectric relaxation and defect concentration was attributed to the existence of the grain boundary defect, interface defect and shallow trap level in the films. An equivalent circuit was established which can well explain the AC response and identify the contribution of defects on electrical properties of BST thin film. From the viewpoint of trapping phenomena and dielectric relaxation analyses, we propose Ir as the optimum material for bottom electrode to withstand the post-annealing treatment. (C) 1998 Elsevier Science S.A. All rights reserved.
Effect of bottom electrodes on resistance degradation and breakdown of (Ba, Sr)TiO3 thin films
(2000-03-01)
Tsai, MS
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The influence of bottom electrodes (Pt, Ir, Ru) on the degradation of (Ba,Sr)TiO3 (BST) thin films under dc stress conditions was investigated. The current-time (I-t) end current-voltage (I-V) measurement results indicated that the BST thin films deposited on Ru have faster degradation than those deposited on Pt and Ir. The degradation was considered to be caused by the deterioration of Schottky-barrier. Under de stress conditions, the dielectric relaxation current in the BST dielectric films probably enhances the deterioration. The breakdown time was found to be approximated by an exponential function of an electric field [t(B) = alpha exp(-beta E)] for dc stress. The value of the exponential factor beta for BST deposited on Pt and Ir was about a quarter of that for BST deposited on Ru. The different value of beta observed under de stress indicates that the degradation of BST on Ru would be more serious than on Pt and Ir. The ten Sears lifetime of time-dependent dielectric breakdown (TDDB) studies indicate that BST on Pt, Ir and Ru have longer lifetime over ten years on operation at the voltage bias of 1 V.
Effect of oxygen to argon ratio on defects and electrical conductivities in Ba0.47Sr0.53TiO3 thin-film capacitors
(1999-09-07)
Tsai, MS
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The ionic and electronic conductivity characteristics and defects in the Ba0.47Sr0.53TiO3 (BST) thin films that were rf-sputtered at 450 degrees C on a Pt bottom electrode at various O-2/(Ar + O-2) mixing ratios (OMR) were studied. The dielectric properties specific to the BST films can be explained by considering the influence of the dielectric relaxation phenomenon. Through the measurement of the dielectric dispersion as a function of frequency (100 Hz less than or equal to f less than or equal to 10 MHz) and temperature (27 degrees C less than or equal to T less than or equal to 150 degrees C), we studied the dielectric relaxation and obtained the defect quantity of the films, on the basis of the capacitance, admittance and impedance spectra. The defect density of BST films decreases with an increase of OMR. The majority of electrical conductivity is carried by electrons (electronic conductivity) and not the ionic defects (ionic conductivity).
Effect of oxygen to argon ratio on properties of (Ba,Sr)TiO3 thin films prepared by radio-frequency magnetron sputtering
(1997-10-01)
Tsai, MS
;
Sun, SC
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Thin films of (Ba,Sr)TiO3 on Pt/SiO2/Si substrates were deposited using rf magnetron sputtering at various substrate temperatures and O-2/(Ar + O-2) mixing ratios (OMR). The crystallinity of the films improved significantly as the OMR increased. The dielectric constant increased with increasing OMR and reached a maximum value at 50% OMR. The leakage current density decreased with increasing oxygen flow, but had a minimum value at 40% OMR. The results for the dielectric constant and the leakage current were interpreted in terms of polarization effect and loss theory, The film deposited at 450 degrees C and 50% OMR exhibited good surface morphology add had a dielectric constant of 375, a tangent loss of 0.074 at 100 kHz, a leakage current density of 7.35 X 10(-9) A/cm(2) at an electric field of 100 kV/cm with a delay time of 30 s, and a charge storage density of 49 fC/mu m(2) at an applied field of 150 kV/cm. The 10 yr lifetime of time-dependent dielectric breakdown studies indicate that a 50% OMR sample has a longer lifetime than the 0% OMR sample. (C) 1997 American Institute of Physics.
Effect of surface passivation removal on planarization efficiency in Cu abrasive-free polishing
(2006)
Fang, JY
;
Tsai, MS
;
Dai, BT
;
Wu, YS
;
Feng, MS
Selective removal of surface passivation on protruded Cu film is a critical factor of Cu planarization. For a stress-free Cu abrasive-free polishing (Cu AFP) process, due to the lack of mechanical abrasion by abrasives, a polishing pad is used instead of abrasives to remove surface passivation during Cu planarization. Thus, the planarization efficiency in Cu AFP relates to the efficiency of surface passivation removed by a pad. Comparing Cu oxides with a non-native Cu-BTA (Cu-Benzotriazole) monolayer used as surface passivation, this study found that an oxide-free Cu surface should be required in Cu AFP. When Cu oxides function as surface passivation in Cu AFP, they are removed with greater difficulty by a pad resulting in low planarization efficiency. Contrary to Cu oxides, high planarization efficiency can be obtained with non-native Cu-BTA as surface passivation in Cu AFP. (c) 2005 The Electrochemical Society.
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.
Electrical properties of O-2 and N-2 annealed (Ba,Sr)TiO3 thin films
(1998-01-01)
Tsai, MS
;
Sun, SC
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The dielectric constant and the leakage current of (Ba,Sr)TiO3 (BST) thin films deposited on Pt bottom electrodes before and after annealing in O-2 and N-2 ambients were investigated. The crystallinity was improved after postdeposition annealing. The refractive index, dielectric constant, and leakage current of the films were strongly dependent on the annealing conditions. The O-2-annealed BST films have higher dielectric constant and lower leakage current than those annealed in N-2 ambient.
Electrical properties of O-2 and N-2 annealed (Ba,Sr)TiO3 thin films
(1998-01-01)
Tsai, MS
;
Sun, SC
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The dielectric constant and the leakage current of (Ba,Sr)TiO3 (BST) thin films deposited on Pt bottom electrodes before and after annealing in O-2 and N-2 ambients were investigated. The crystallinity was improved after postdeposition annealing. The refractive index, dielectric constant, and leakage current of the films were strongly dependent on the annealing conditions. The O-2-annealed BST films have higher dielectric constant and lower leakage current than those annealed in N-2 ambient.