• Applied Chemistry for Engineering
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• 제18권1호
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• pp.24-28
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• 2007

The etching of zinc oxide (ZnO) thin films has been studied using a high density plasma in a $Cl_2/Ar$ gas. The etch characteristics of ZnO thin films were systematically investigated on varying $Cl_2$ concentration, coil rf power, dc-bias voltage, and gas pressure. With increasing $Cl_2$ concentration, the etch rate of ZnO thin film increased, the redeposition around the etched patterns decreased but the sidewall slope of the etched patterns slanted. As the coil rf power and dc-bias voltage increased, the etch rates of ZnO thin films increased and etch profiles of ZnO thin films were improved. With increasing gas pressure, the etch rate of ZnO thin films slightly increased but little change in etch profile was observed. Based on these results, the optimal etching conditions of ZnO thin film were selected. Finally, the etching of ZnO thin films with a high degree of anisotropy of approximately $75^{\circ}{\sim}80^{\circ}$ without the redepositions and residues was successfully achieved at the etching conditions of 20% $Cl_2$ concentration, coil rf power of 1000 W, dc-bias voltage of 400 V, and gas pressure of 5 mTorr.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.174-174
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• 2010

In this article, the dry etching mechanism of ZnO thin films in $N_2/Cl_2$/Ar gas chemistry was investigated. The ZnO thin films were deposited on Si substrate using Atomic layer deposition. The etching experiments were performed by inductively coupled plasma system. The maximum etch rate was104.5 nm/min and the highest selectivity of ZnO over $SiO_2$ was 3.3. Etching rate was measured by surface profiler. And the chemical reaction on the surface of the etched ZnO thin films was investigated by x-ray photo electrons pectroscopy. As a result of XPS, $Zn2p_{3/2}$ peak shifted toward a higher binding energy and the O-O and N-O bond were obtained from the sample of ZnO thin film which after plasma treatment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.400-403
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• 2003

Etching characteristics of (Pb,Sr)$TiO_3$(PST) thin films were investigated using inductively coupled chlorine based plasma system as functions of gas mixing ratio, RF power and DC bias voltage. It was found that increasing of Ar content in gas mixture lead to sufficient increasing of etch rate and selectivity of PST to Pt. The maximum etch rate of PST film is $562\;{\AA}$/min and the selectivity of PST film to Pt is 0.8 at $Cl_2/(Cl_2+Ar)$ of 20 %. It was proposed that sputter etching is dominant etching mechanism while the contribution of chemical reaction is relatively low due to low volatility of etching products.

• Proceedings of the KIEE Conference
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1364-1366
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• 1997

Planar type magnetized inductively coupled plasma etcher has been built. The density and temperature of Ar plasma are measured as a function of rf power, external magnetic field, and pressure. The oxide etch rate and selectivity to polysilicon are measured as the above mentioned conditions and self-bias voltage.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제16권6호
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• pp.460-464
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• 2003

The barium strontium titannate ((Ba,Sr)TiO$_3$:BST) thin films were etched in an inductively coupled plasma (ICP) as a function of CF$_4$/Ar gas mixing ratio. Under CF$_4$(20%)/Ar(80%), the maximum etch rate of the BST films was 400 $\AA$/min. Etching products were redeposited on the surface of BST and then the nature of crystallinity were varied. Therefore, we investigated the etched surface of BST by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The plasma damages were evaluated in terms of leakage current density by Agilent 4145C and dielectric constant by HP 4192 impedance analyzer. After the BST thin films exposed in the plasma, the leakage current density and roughness increases. After annealing at 600 $^{\circ}C$ for 10 min in $O_2$ ambient, the leakage current density, roughness and nonvolatile etch byproducts reduced. From this results, the plasma induced damages were recovered by annealing process owing to the relaxation of lattice mismatches by Ar ions and the desorption of metal fluorides in high temperature.

• Transactions on Electrical and Electronic Materials
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• 제12권4호
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• pp.144-147
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• 2011

In this work, we present a study regarding the etching characteristics on titanium nitride (TiN) thin films using an inductively coupled plasma system. The TiN thin film was etched using a $N_2/BCl_3$/Ar plasma. The studied etching parameters were the gas mixing ratio, the radio frequency (RF) power, the direct current (DC)-bias voltages, and the process pressures. The baseline conditions were as follows: RF power = 500 W, DC-bias voltage = -150 V, substrate temperature = $40^{\circ}C$, and process pressure = 15 mTorr. The maximum etch rate and the selectivity of the TiN to the $SiO_2$ thin film were 62.38 nm/min and 5.7, respectively. The X-ray photoelectron spectroscopy results showed no accumulation of etching byproducts from the etched surface of the TiN thin film. Based on the experimental results, the etched TiN thin film was obtained by the chemical etching found in the reactive ion etching mechanism.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.164-165
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• 2005

The dry etch characteristics of GaAs over both AlGaAs and InGaP in planar inductively coupled $BCl_3$-based plasmas(ICP) with additions of $SF_6$ or $CF_4$ were studied. The additions of flourine gases provided enhanced etch selectivities of GaAs/AlGaAs and GaAs/InGaP. The etch stop reaction involving formation of involatile $AlF_3$ and $InF_3$ (boiling points of etch products: $AlF_3\sim1300^{\circ}C$, $InF_3$ > $1200^{\circ}C$ at atmosphere) were found to be effective under high density inductively coupled plasma condition. Decrease of etch rates of all materials was probably due to strong increase of flourine atoms in the discharge, which blocked the surface of the material against chlorine neutral adsorption. The process parameters were ICP source power (0 - 500 W), RF chuck power (0 - 30 W) and variable gas composition. The process results were characterized in terms of etch rate, selectivities of GaAs over AlGaAs and InGaP, surface morphology, surface roughness and residues after etching.

• Korean Journal of Materials Research
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• 제17권12호
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• pp.642-647
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• 2007

We investigated dry etching of acrylic (PMMA) in $O_2/N_2$ plasmas using a multi-layers electrode reactive ion etching (RIE) system. The multi-layers electrode RIE system had an electrode (or a chuck) consisted of 4 individual layers in a series. The diameter of the electrodes was 150 mm. The etch process parameters we studied were both applied RIE chuck power on the electrodes and % $O_2$ composition in the $N_2/O_2$ plasma mixtures. In details, the RIE chuck power was changed from 75 to 200 W.% $O_2$ in the plasmas was varied from 0 to 100% at the fixed total gas flow rates of 20 sccm. The etch results of acrylic in the multilayers electrode RIE system were characterized in terms of negatively induced dc bias on the electrode, etch rates and RMS surface roughness. Etch rate of acrylic was increased more than twice from about $0.2{\mu}m/min$ to over $0.4{\mu}m/min$ when RIE chuck power was changed from 75 to 200 W. 1 sigma uniformity of etch rate variation of acrylic on the 4 layers electrode was slightly increased from 2.3 to 3.2% when RIE chuck power was changed from 75 to 200 W at the fixed etch condition of 16 sccm $O_2/4\;sccm\;N_2$ gas flow and 100 mTorr chamber pressure. Surface morphology was also investigated using both a surface profilometry and scanning electron microscopy (SEM). The RMS roughness of etched acrylic surface was strongly affected by % $O_2$ composition in the $O_2/N_2$ plasmas. However, RIE chuck power changes hardly affected the roughness results in the range of 75-200 W. During etching experiment, Optical Emission Spectroscopy (OES) data was taken and we found both $N_2$ peak (354.27 nm) and $O_2$ peak (777.54 nm). The preliminarily overall results showed that the multi-layers electrode concept could be successfully utilized for high volume reactive ion etching of acrylic in the future.

• The Transactions of the Korean Institute of Electrical Engineers C
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• 제49권8호
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• pp.438-444
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• 2000

We report the effects of etch process parameters on the ohmic contact formation in the plasma etching of GaN. Planar inductively coupled plasma system with $CH_4/H_2/Ar$gas chemistry has been used as etch reactor. The contact resistance and the specific contact resistance have been investigated using transfer length method as a function of RF bias power and %Ar gas concentration in total flow rate. AES(Auger electron spectroscopy) analysis revealed that the etched GaN has nonstoichiometric Ga rich surface and was contaminated by carbon and oxygen. Especially large amount of carbon was detected at the sample etched for high bias power (or voltage) condition, where severe degradation of contact resistance was occurred. We achieved the low ohmic contact of $2.4{\times}10^{-3} {\Omega}cm^2$ specific contact resistance at the input power 400 W, RF bias power 150 W, and working pressure 10mTorr with 10 sccm $CH_4$, 15 sccm H2, 5 sccm Ar gas composition.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제26권11호
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• pp.826-830
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• 2013

In this paper, we carried out the investigations of both etch characteristics and mechanisms for the $SnO_2$ thin films in $O_2/BCl_3/Ar$ plasma. The dry etching characteristics of the $SnO_2$ thin films was studied by varying the $O_2/BCl_3/Ar$ gas mixing ratio. We determined the optimized process conditions that were as follows: a RF power of 700 W, a DC-bias voltage of - 150 V, and a process pressure of 2 Pa. The maximum etch rate was 509.9 nm/min in $O_2/BCl_3/Ar$=(3:4:16 sccm) plasma. From XPS analysis, the etch mechanism of the $SnO_2$ thin films in the $O_2/BCl_3/Ar$ plasma can be identified as the ion-assisted chemical reaction while the role of ion bombardment includes the destruction of the metal-oxide bonds as well as the cleaning of the etched surface form the reaction products.