Doo-Seung Um

Dry Etching of Al 2 O 3 Thin Films in O 2 /BCl 3 /Ar Inductively Coupled Plasma

In this study, the etch properties of Al2O3 thin films deposited by atomic layer deposition were investigated as a function of the O2 content in BCl3/Ar inductively coupled plasma. The experiments were performed by comparing the etch rates and selectivity of Al2O3 over the hard mask materials as functions of the input plasma parameters, such as the gas mixing ratio, DC-bias voltage, ratio-frequency (RF) power and process pressure. The highest obtained etch rate was 477 nm/min at an RF power of 700 W, O2 to BCl3/Ar gas ratio of 15%, DC-bias voltage of -100 V and process pressure of 15 mTorr. The deposition occurred on the surfaces when the amount of O2 added to the BCl3/Ar gas was too high at a low DC-bias voltage or high process pressure. X-ray photoelectron spectroscopy was used to investigate the chemical reactions on the etched surface.

Dry-etching properties of TiN for metal/high-k gate stack using BCl3-based inductively coupled plasmaa)

The etch rate of TiN film and the selectivities of TiN∕SiO2 and TiN∕HfO2 were systematically investigated in Cl2∕BCl3∕Ar plasmas as functions of Cl2 flow rate, radio-frequency (rf) power, and direct-current (dc) bias voltage under different substrate temperatures of 10 and 80°C. The etch rate of TiN films increased with increasing Cl2 flow rate, rf power, and dc-bias voltage at a fixed substrate temperature. In addition, the etch rate of TiN films at 80°C were higher than that at 10°C when other plasma parameters were fixed. However, the selectivities of TiN∕SiO2 and TiN∕HfO2 showed different tendencies compared with etch-rate behavior as a function of rf power and dc bias voltage. The relative-volume densities of Ar (750.0nm), Cl (725.2nm), and Cl+ (386.6nm) were monitored with an optical-emission spectroscopy. When rf power increased, the relative-volume densities of all studied particles were increased. X-ray photoelectron spectroscopy was carried out to detect nonvolatile etch by-products from the sur...

Temperature dependence on dry etching of Al2O3 thin films in BCl3/Cl2/Ar plasma

During the etching process, the wafer surface temperature is an important parameter which influences the reaction probabilities of incident species, the vapor pressure of etch products, and the redeposition of reaction products on feature surfaces. In this study, the authors investigated that the effect of substrate temperature on the etch rate of Al2O3 thin film and selectivity of Al2O3 thin film over hard mask material (such as SiO2) thin film in inductively coupled plasma as functions of Cl2 addition in BCl3/Ar plasma, rf power, and dc-bias voltage based on the substrate temperature in range of 10–80 °C. The elements existed on the surface were analyzed by energy dispersive x-ray and x-ray photoelectron spectroscopy.

Dry etching of CoFe films using a CH4∕Ar inductively coupled plasma for magnetic random access memory application

In this study, the CoFe thin film was studied using an inductively coupled plasma system in CH4-based gas chemistries. The etch rate of the CoFe thin film was systemically studied by the process parameters including the gas mixing ratio, the rf power, the dc-bias power, and the process pressure. The best gas composition for etching was in CH4 (20%)/Ar (80%) ratio. As the rf power and the dc-bias voltage were increased, the etch rate of the CoFe thin film increased in a CH4∕Ar inductively coupled plasma system. The best process pressure condition for etching was 10mTorr in the CH4∕Ar inductively coupled plasma system. The changes in the components on the surface of the CoFe thin film were investigated with energy dispersive x ray.

The Etching Properties of Al2O3 Thin Films in BCl3/Cl2/Ar Plasma

In this study, the etch mechanism of ALD deposited Al2O3 thin film was investigated in BCl3/Cl2/Ar plasma. The experiments were performed by comparing etch rates and selectivity of Al2O3 over hard mask materials (such as SiO2, and Si3N4) as function of the input plasma parameters such as gas mixing ratio, DC-bias voltage and RF power under fixed process pressure. The maximum etch rate was obtained at 115.75 nm/min under 5 mTorr, RF power 600 W, Cl2 10% was added to BCl3/Ar plasma, and the highest etch selectivity was 1.17 over Si3N4 under the 10 mTorr process pressure, −50 V DC-bias voltage. We used the X-ray photoelectron spectroscopy (XPS) to investigate the chemical reactions on the etched surface.

Etching Properties of HfO2 Thin Films in Cl2/BCl3/Ar Plasma

In this study, we changed two input parameters (pressure vs. gas mixing ratio, RF power and DC bias voltage) and then monitored the effect on HfO 2 etch rate and selectivity with Si 3 N 4 and SiO 2 . When the pressure was fixed at 5 mTorr, etch rate of HfO 2 decreased with increasing Cl 2 content from 0 to 30% in BCl 3 /Ar plasma. At the conditions of 10 and 15 mTorr, the HfO 2 etch rate reached the maximum at 10% Cl 2 addition. As RF power and DC bias voltage increased in all ranges of pressure conditions, etch rates for HfO 2 showed increasing trends. The relative volume densities of radicals were monitored with optical emission spectroscopy (OES). The analysis of x-ray photoelectron spectroscopy (XPS) was carried out to investigate the chemical reactions between the surfaces of HfO 2 and etch species. Based on experimental data, the ion-assisted chemical etching was proposed as the main etch mechanism for the HfO 2 thin films in Cl 2 /BCl 3 /Ar plasma.

Improving the Etch Selectivity of ZrO2 Thin Films over Si by Using High Density Plasma

In this study, we carried out an investigation of the etching characteristics (etch rate, selectivity to Si) of ZrO 2 thin films in the HBr/CF 4 high density plasma (HDP) system. The maximum etch rate of 70.8 nm/min for ZrO2 thin films was obtained at HBr(75%)/ CF 4 (25%) gas mixing ratio. At the same time, the etch rate was measured as a function of the etching parameter such as HDP chamber pressure. The X-ray photoelectron spectroscopy (XPS) analysis showed an efficient destruction of the oxide bonds by the ion bombardment as well as an accumulation of low volatile reaction products on the etched surface. Based on these data, the ion-assisted chemical reaction was proposed as the main etch mechanism for the CF 4 -containing plasmas.

Etch Characteristics of ZrO2 Thin Films in High Density Plasma

In this work, we investigated the etching characteristics of ZrO2 thin film and the selectivity of ZrO2 thin film to Si in the HBr/CF4 high density plasma (HDP) system. The maximum etch rate of 70.8 nm/min for ZrO2 thin film was obtained at HBr (75%)/CF4 (25%) gas mixing ratio. At the same time, the etch rate was measured as functions of the etching parameters such as HDP source power, bias power and temperature. The angle-resolved X-ray photoelectron spectroscopy analysis showed an efficient destruction of the oxide bonds by the ion bombardment as well as an accumulation of low volatile reaction products on the etched surface. Based on these data, the ion-assisted chemical reaction was proposed as the main etch mechanism of ZrO2 for the CF4-containing plasmas.

Dry Etching Characteristics of ZrO2 Thin Films Using High Density Cl2/Ar Plasma

The etch rates of ZrO2 thin films and the etch selectivity of ZrO2 to SiO2 in a Cl2/Ar plasma were investigated. It was found that the ZrO2 etch rate showed non-monotonic behaviour with increasing Ar fraction in the Cl2 plasma, but etch rate showed a monotonic trend with increasing source power, bias power, and substrate temperature. The maximum ZrO2 etch rate of 92.6 nm/min was obtained for the Cl2 (75%) /Ar (25%) gas mixture. At the same time, the relative volume densities of the radicals were monitored with optical emission spectroscopy (OES). The Auger electron spectroscopy (AES) analysis showed the efficient destruction of the oxide bonds from Zr-O bonds by the ion bombardment, as well as an accumulation of low volatile reaction product of Zr-Clx on the etched surface. Based on the experimental data, ion-assisted chemical etching was proposed as the main etch mechanism for the ZrO2 in the Cl2/Ar plasma.

The Etch Characteristics of the CoFe Thin Film Using an Inductively Coupled Plasma System

In this study, the etching characteristics of the CoFe thin film were investigated by using an inductively coupled plasma system and CH3OH-based gas chemistries. The etch rate of the CoFe thin film and the selectivity of CoFe to Ta was systemically studied as a function of the process parameters including a CH3OH/Ar gas mixing ratio, the DC-bias voltage, the RF power, the process pressure, the substrate temperature and amount of O2 added. The highest etch rate of the CoFe thin film was 40.5 nm/min and the best selectivity of CoFe to Ta was 29.9. The chemical reaction on the surface of the CoFe thin film was studied using X-ray photoelectron spectroscopy (XPS).