PROBLEM TO BE SOLVED: To prevent damage to a semiconductor substrate and realize improvement in y... more PROBLEM TO BE SOLVED: To prevent damage to a semiconductor substrate and realize improvement in yield of process, by first forming a narrow trench and a wide trench on the surface of a nitride film and an oxide film so as to perform surface treatment under predetermined conditions, and then depositing an insulating film which causes the deposition rate to be low on the nitride film and high on the oxide film. SOLUTION: A pad oxide film 13 is formed on an upper part of a semiconductor substrate 11, and a nitride film 15 is formed on the entire surface thereof. Then, a narrow trench 17 and a wide trench 18 are formed in a cell region 100 and a peripheral circuit region 200 on the semiconductor substrate 11 in an etching process using an element isolation mask. An oxide film 19 is formed on the surface of the trench 17, and the surface of the oxide film 19 is treated to have positive charges. After that, the deposition rate is caused to be low on the nitride film 15 and high on the oxi...
An oxide film etched in a magnetically-enhanced CHF yCF plasma has been modeled using neural netw... more An oxide film etched in a magnetically-enhanced CHF yCF plasma has been modeled using neural networks. The etch process 34 was characterized with a 2 factorial experiment. The experimental factors and ranges include 20–80 sccm CHF flow rate, 4y1 3 10–40 sccm CF flow rate, 300–800 W radio frequency (RF) power, and 50–200 mTorr pressure. Radicals (F, CF , and CF ) 4 12 measured with optical emission spectroscopy were related to etch responses. In the experiments conducted, increases in etch rate generally corresponded to decreases in nonuniformity. Etch nonuniformity was strongly dependent on RF power. The relative significance of polymer deposition and ion bombardment was separated and explained. The root-mean-squared prediction errors are 174 Aymin and 0.425% for etch rate and etch nonuniformity models, respectively. ˚ 2002 Elsevier Science B.V. All rights reserved.
The effect of process parameters on H2 production from water vapor excited by HF ICP has been qua... more The effect of process parameters on H2 production from water vapor excited by HF ICP has been qualitatively examined for the first time. With the increase of ICP power, characteristics of H2 production from H2O dissociation in plasma was divided into 3 regions according to both reaction mechanism and energy efficiency. At the edge of region (Ⅱ) in the range of middle ICP power, energy effective hydrogen production from H2O plasma can be achieved. Furthermore, within the region (Ⅱ) power condition, heating of substrate up to 500℃ shows additional increase of 70∼80% in H2 production compared to H2O plasma without substrate heating. This study have shown that combination of optimal plasma power (region Ⅱ) and wall heating (around 500℃) is one of effective ways for H2 production from H2O.
Via profiles of oxide films were qualitatively modeled using a neural network. The oxide films we... more Via profiles of oxide films were qualitatively modeled using a neural network. The oxide films were magnetically etched in a CHF3/CF4 plasma with various radio-frequency (RF) powers, pressures, and CHF3 and CF4 flow rates. A statistical 2 4−1 fractional factorial experiment was conducted to characterize the behavior of the via profile. The neural network was trained on nine experiments, and the trained model was evaluated on another eight experiments, not belonging to the training data. As a function of the training factors, the prediction accuracy of profile model was optimized, and the optimized model had a prediction error of 3.05 • . Compared to the statistical regression model, this was about a 43 % improvement in the prediction accuracy. Using the model, we made several 3-D plots to unveil underlying etch mechanisms, including the factor interaction effects, involved in via formation. As expected, the profile angle decreased with increasing RF power without regard to the press...
In-situ cleaning and subsequent silicon epitaxial film growth were performed in a load-locked rea... more In-situ cleaning and subsequent silicon epitaxial film growth were performed in a load-locked reactor equipped with Hg-grid UV lamp and PBN heater to obtain the smooth and contaminant-free underlying surface and develop low-temperature epitaxial film growth process. The removals of organic and native oxide were investigated using UV-excited and , and the effect of the surface condition was examined on the quality of silicon epitaxial film grown at temperature as low as . UV-excited gas phase cleaning was found to be effective in removing the organic and native oxide successfully providing a smooth surface with RMS roughness of 0.5 at optimal condition. Crystalline quality of epitaxial film was determined by smoothness of cleaned surface and the presence of native oxide and impurity. Crystalline defects such as dislocation loops or voids due to the surface roughness were observed by XTEM.
direction with a temperature decrease and the peak current showed a strong dependence on frequenc... more direction with a temperature decrease and the peak current showed a strong dependence on frequency at constant temperature. The standard enthalpy and entropy determined were 75 kJ/mol and 23 J/molK, respectively. The activation energy for the diffusion of iron was 148 kJ/mol. The redox ratio, [Fe 2+ ]/[Fe 3+ ] calculated under the assumption that the melt is in equilibrium with air lay in the range 0.02~0.11. By comparison of the thermodynamic properties and the diffusion coefficient of the present melt with those of other silicate melts cited in the literature, the dependence of the peak potential on alkali concentration and, the relation between the self-diffusion coefficient and viscosity are discussed.
The effect of process parameters on H 2 production from water vapor excited by HF ICP has been qu... more The effect of process parameters on H 2 production from water vapor excited by HF ICP has been qualitatively examined for the first time. With the increase of ICP power, characteristics of H 2 production from H 2 O dissociation in plasma was divided into 3 regions according to both reaction mechanism and energy efficiency. At the edge of region (II) in the range of middle ICP power, energy effective hydrogen production from H 2 O plasma can be achieved. Furthermore, within the region (II) power condition, heating of substrate up to 500℃ shows additional increase of 70∼80% in H 2 production compared to H 2 O plasma without substrate heating. This study have shown that combination of optimal plasma power (region II) and wall heating (around 500℃) is one of effective ways for H 2 production from H 2 O.KEY WORDS : Hydrogen production(수소생산), ICP reactor(유도결합플라즈마반응기), Water dissociation (물분해), Process parameters study(공정변수연구), Plasma(플라즈마) 한국수소 및 신에너지학회 논문집(2011. 4), 제22권 제2호Trans. of the...
This study examines the effect of removing unburned carbon from fly ash depending on the treatmen... more This study examines the effect of removing unburned carbon from fly ash depending on the treatment time associated with the cold plasma conditions and the characteristics of the fly ash powder during the process. The optimum conditions for the cold plasma process at the substrate temperature of 150 included the gas type of O2, 200 W power, gas flow of 50 sccm, and the one-time treatment time of 10 minutes. Moreover, under these conditions, the loss on ignition of fly ash decreased from 5.8% to 1.0%. The loss on ignition decreased to 0.1% when the process was implemented eight times (10 minutes × 8 cycles) under optimum conditions. As unburned carbon was removed from the fly ash during the cold plasma process, the BET specific surface area decreased from 5,809 m/kg to 1,597 m/kg, whereas the mean particle size decreased from 15.5 μm to 11.7 μm and the particle-size distribution narrowed. The unburned carbon particles became smaller in size as their micropores eliminated in the plasma...
PROBLEM TO BE SOLVED: To prevent damage to a semiconductor substrate and realize improvement in y... more PROBLEM TO BE SOLVED: To prevent damage to a semiconductor substrate and realize improvement in yield of process, by first forming a narrow trench and a wide trench on the surface of a nitride film and an oxide film so as to perform surface treatment under predetermined conditions, and then depositing an insulating film which causes the deposition rate to be low on the nitride film and high on the oxide film. SOLUTION: A pad oxide film 13 is formed on an upper part of a semiconductor substrate 11, and a nitride film 15 is formed on the entire surface thereof. Then, a narrow trench 17 and a wide trench 18 are formed in a cell region 100 and a peripheral circuit region 200 on the semiconductor substrate 11 in an etching process using an element isolation mask. An oxide film 19 is formed on the surface of the trench 17, and the surface of the oxide film 19 is treated to have positive charges. After that, the deposition rate is caused to be low on the nitride film 15 and high on the oxi...
An oxide film etched in a magnetically-enhanced CHF yCF plasma has been modeled using neural netw... more An oxide film etched in a magnetically-enhanced CHF yCF plasma has been modeled using neural networks. The etch process 34 was characterized with a 2 factorial experiment. The experimental factors and ranges include 20–80 sccm CHF flow rate, 4y1 3 10–40 sccm CF flow rate, 300–800 W radio frequency (RF) power, and 50–200 mTorr pressure. Radicals (F, CF , and CF ) 4 12 measured with optical emission spectroscopy were related to etch responses. In the experiments conducted, increases in etch rate generally corresponded to decreases in nonuniformity. Etch nonuniformity was strongly dependent on RF power. The relative significance of polymer deposition and ion bombardment was separated and explained. The root-mean-squared prediction errors are 174 Aymin and 0.425% for etch rate and etch nonuniformity models, respectively. ˚ 2002 Elsevier Science B.V. All rights reserved.
The effect of process parameters on H2 production from water vapor excited by HF ICP has been qua... more The effect of process parameters on H2 production from water vapor excited by HF ICP has been qualitatively examined for the first time. With the increase of ICP power, characteristics of H2 production from H2O dissociation in plasma was divided into 3 regions according to both reaction mechanism and energy efficiency. At the edge of region (Ⅱ) in the range of middle ICP power, energy effective hydrogen production from H2O plasma can be achieved. Furthermore, within the region (Ⅱ) power condition, heating of substrate up to 500℃ shows additional increase of 70∼80% in H2 production compared to H2O plasma without substrate heating. This study have shown that combination of optimal plasma power (region Ⅱ) and wall heating (around 500℃) is one of effective ways for H2 production from H2O.
Via profiles of oxide films were qualitatively modeled using a neural network. The oxide films we... more Via profiles of oxide films were qualitatively modeled using a neural network. The oxide films were magnetically etched in a CHF3/CF4 plasma with various radio-frequency (RF) powers, pressures, and CHF3 and CF4 flow rates. A statistical 2 4−1 fractional factorial experiment was conducted to characterize the behavior of the via profile. The neural network was trained on nine experiments, and the trained model was evaluated on another eight experiments, not belonging to the training data. As a function of the training factors, the prediction accuracy of profile model was optimized, and the optimized model had a prediction error of 3.05 • . Compared to the statistical regression model, this was about a 43 % improvement in the prediction accuracy. Using the model, we made several 3-D plots to unveil underlying etch mechanisms, including the factor interaction effects, involved in via formation. As expected, the profile angle decreased with increasing RF power without regard to the press...
In-situ cleaning and subsequent silicon epitaxial film growth were performed in a load-locked rea... more In-situ cleaning and subsequent silicon epitaxial film growth were performed in a load-locked reactor equipped with Hg-grid UV lamp and PBN heater to obtain the smooth and contaminant-free underlying surface and develop low-temperature epitaxial film growth process. The removals of organic and native oxide were investigated using UV-excited and , and the effect of the surface condition was examined on the quality of silicon epitaxial film grown at temperature as low as . UV-excited gas phase cleaning was found to be effective in removing the organic and native oxide successfully providing a smooth surface with RMS roughness of 0.5 at optimal condition. Crystalline quality of epitaxial film was determined by smoothness of cleaned surface and the presence of native oxide and impurity. Crystalline defects such as dislocation loops or voids due to the surface roughness were observed by XTEM.
direction with a temperature decrease and the peak current showed a strong dependence on frequenc... more direction with a temperature decrease and the peak current showed a strong dependence on frequency at constant temperature. The standard enthalpy and entropy determined were 75 kJ/mol and 23 J/molK, respectively. The activation energy for the diffusion of iron was 148 kJ/mol. The redox ratio, [Fe 2+ ]/[Fe 3+ ] calculated under the assumption that the melt is in equilibrium with air lay in the range 0.02~0.11. By comparison of the thermodynamic properties and the diffusion coefficient of the present melt with those of other silicate melts cited in the literature, the dependence of the peak potential on alkali concentration and, the relation between the self-diffusion coefficient and viscosity are discussed.
The effect of process parameters on H 2 production from water vapor excited by HF ICP has been qu... more The effect of process parameters on H 2 production from water vapor excited by HF ICP has been qualitatively examined for the first time. With the increase of ICP power, characteristics of H 2 production from H 2 O dissociation in plasma was divided into 3 regions according to both reaction mechanism and energy efficiency. At the edge of region (II) in the range of middle ICP power, energy effective hydrogen production from H 2 O plasma can be achieved. Furthermore, within the region (II) power condition, heating of substrate up to 500℃ shows additional increase of 70∼80% in H 2 production compared to H 2 O plasma without substrate heating. This study have shown that combination of optimal plasma power (region II) and wall heating (around 500℃) is one of effective ways for H 2 production from H 2 O.KEY WORDS : Hydrogen production(수소생산), ICP reactor(유도결합플라즈마반응기), Water dissociation (물분해), Process parameters study(공정변수연구), Plasma(플라즈마) 한국수소 및 신에너지학회 논문집(2011. 4), 제22권 제2호Trans. of the...
This study examines the effect of removing unburned carbon from fly ash depending on the treatmen... more This study examines the effect of removing unburned carbon from fly ash depending on the treatment time associated with the cold plasma conditions and the characteristics of the fly ash powder during the process. The optimum conditions for the cold plasma process at the substrate temperature of 150 included the gas type of O2, 200 W power, gas flow of 50 sccm, and the one-time treatment time of 10 minutes. Moreover, under these conditions, the loss on ignition of fly ash decreased from 5.8% to 1.0%. The loss on ignition decreased to 0.1% when the process was implemented eight times (10 minutes × 8 cycles) under optimum conditions. As unburned carbon was removed from the fly ash during the cold plasma process, the BET specific surface area decreased from 5,809 m/kg to 1,597 m/kg, whereas the mean particle size decreased from 15.5 μm to 11.7 μm and the particle-size distribution narrowed. The unburned carbon particles became smaller in size as their micropores eliminated in the plasma...
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