• Transactions on Electrical and Electronic Materials
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• v.15 no.3
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• pp.164-169
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• 2014

We investigated the etching characteristics of $HfAlO_3$ thin films in $O_2/Cl_2/Ar$ and $O_2/BCl_3/Ar$ gas, using a high-density plasma (HDP) system. The etch rates of the $HfAlO_3$ thin film obtained were 30.1 nm/min and 36 nm/min in the $O_2/Cl_2/Ar$ (3:4:16 sccm) and $O_2/BCl_3/Ar$ (3:4:16 sccm) gas mixtures, respectively. At the same time, the etch rate was measured as a function of the etching parameter, namely as the process pressure. The chemical states on the surface of the etched $HfAlO_3$ thin films were investigated by X-ray photoelectron spectroscopy. Auger electron spectroscopy was used for elemental analysis on the surface of the etched $HfAlO_3$ thin films. These surface analyses confirm that the surface of the etched $HfAlO_3$ thin film is formed with nonvolatile by-product. Also, Cl-O can protect the sidewall due to additional $O_2$.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.182-182
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• 2012

Plasma etching is used in various semiconductor processing steps. In plasma etcher, optical- emission spectroscopy (OES) is widely used for in-situ endpoint detection. However, the sensitivity of OES is decreased if polymer is deposited on viewport or the proportion of exposed area on the wafer is too small. Because of these problems, the object is to investigate the suitability of using plasma impedance monitoring (PIM) and self plasma optical emission spectrocopy (SPOES) with statistical approach for in-situ endpoint detection. The endpoint was determined by impedance signal variation from I-V monitor (VI probe) and optical emission signal from SPOES. However, the signal variation at the endpoint is too weak to determine endpoint when $SiO_2$ and SiNx layers are etched by fluorocarbon on inductive coupled plasma (ICP) etcher, if the proportion of $SiO_2$ and SiNx area on Si wafer are small. Therefore, modified principal component analysis (mPCA) is applied to them for increasing sensitivity. For verifying this method, detected endpoint from impedance monitoring is compared with optical emission spectroscopy.

• Transactions on Electrical and Electronic Materials
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• v.13 no.6
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• pp.287-291
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• 2012

We investigated the etching characteristics of TaN thin films in an $O_2/BCl_3/Cl_2/Ar$ gas using a high density plasma (HDP) system. A maximum etch rate of the TaN thin films and the selectivity of TaN to $SiO_2$ were obtained as 172.7 nm/min and 6.27 in the $O_2/BCl_3/Cl_2/Ar$ (3:2:18:10 sccm) gas mixture, respectively. At the same time, the etch rate was measured as a function of the etching parameters, such as the RF power, DC-bias voltage, and process pressure. The chemical states on the surface of the etched TaN thin films were investigated using X-ray photoelectron spectroscopy. Auger electron spectroscopy was used for elemental analysis on the surface of the etched TaN thin films. These surface analyses confirm that the surface of the etched TaN thin film is formed with the nonvolatile by-product.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.117-118
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• 2006

In this work, we investigated etching characteristics of $HfO_2$ thin film and Si using inductive coupled plasma (ICP) system. The ion energy distribution functions in an inductively coupled plasma was analyzed by quadrupole mass spectrometer with an electrostatic ion energy analyzer. The maximum etch rate of $HfO_2$ is 85.5 nm/min at a $BCl_3/(BCl_3+Ar)$ of 20% and decreased with further addition of $BCl_3$ gas. From the QMS measurements, the most dominant positive ion energy distributions (IEDs) showed a maximum at 20 % of $BCl_3$. These tendency was very similar to the etch characteristics. This result agreed with the universal energy dependency of ion enhanced chemical etching yields. And the maximum selectivity of $HfO_2$ over Si is 3.05 at a O2 addition of 2 sccm into the $BCl_3/(BCl_3+ Ar)$ of 20% plasma.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.9
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• pp.718-722
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• 2011

In this work, we investigated to the etching characteristics of the TiN thin film in He/$BCl_3/Cl_2$ plasma. The etch rate was measured by the gas mixing ratio, the RF power, the DC bias voltage and the process pressure. The maximum etch rate in He/$BCl_3/Cl_2$ plasma was 59 nm/min. The etch rate increased as the RF power and the DC-bias voltage was increased. The chemical reaction on the surface of the etched the TiN thin films was investigated with X-ray photoelectron spectroscopy (XPS). The intensity of Ti 2p and N 1s peaks are varied during etching process. A new peak was appeared in He/$BCl_3/Cl_2$ plasma. The new peak was revealed Ti-$Cl_x$ by Cl 2p peak of XPS wild scan spectra analysis.

• Transactions on Electrical and Electronic Materials
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• v.15 no.1
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• pp.49-54
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• 2014

In this study, we carried out an investigation of the etch characteristics of silicon (Si) film, and the selectivity of Si to $SiO_2$ in $SF_6/O_2$ plasma. The etch rate of the Si film was decreased on adding $O_2$ gas, and the selectivity of Si to $SiO_2$ was increased, on adding $O_2$ gas to the $SF_6$ plasma. The optical condition of the Si film with this work was 1,350 nm/min, at a gas mixing ratio of $SF_6/O_2$ (=130:30 sccm). At the same time, the etch rate was measured as functions of the various etching parameters. The X-ray photoelectron spectroscopy analysis showed the efficient destruction of oxide bonds by ion bombardment, as well as the accumulation of high volatile reaction products on the etched surface. Field emission auger electron spectroscopy analysis was used to examine the efficiency of the ion-stimulated desorption of the reaction products.

• Transactions on Electrical and Electronic Materials
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• v.14 no.2
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• pp.67-70
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• 2013

In this study, we changed the input parameters (gas mixing ratio, RF power, DC bias voltage, and process pressure), and then monitored the effect on TiN etch rate and selectivity with $SiO_2$. When the RF power, DC-bias voltage, and process pressure were fixed at 700 W, - 150 V, and 15 mTorr, the etch rate of TiN increased with increasing $CF_4$ content from 0 to 20 % in $CF_4$/Ar plasma. The TiN etch rate reached maximum at 20% $CF_4$ addition. As RF power, DC bias voltage, and process pressure increased, all ranges of etch rates for TiN thin films showed increasing trends. The analysis of x-ray photoelectron spectroscopy (XPS) was carried out to investigate the chemical reactions between the surfaces of TiN and etch species. Based on experimental data, ion-assisted chemical etching was proposed as the main etch mechanism for TiN thin films in $CF_4$/Ar plasma.

• Korean Journal of Metals and Materials
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• v.48 no.11
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• pp.1028-1034
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• 2010

In the development of 3D package, through silicon via (TSV) formation technology by using deep reactive ion etching (DRIE) is one of the key processes. We performed the Bosch process, which consists of sequentially alternating the etch and passivation steps using $SF_6$ with $O_2$ and $C_4F_8$ plasma, respectively. We investigated the effect of changing variables on vias: the gas flow time, the ratio of $O_2$ gas, source and bias power, and process time. Each parameter plays a critical role in obtaining a specified via profile. Analysis of via profiles shows that the gas flow time is the most critical process parameter. A high source power accelerated more etchant species fluorine ions toward the silicon wafer and improved their directionality. With $O_2$ gas addition, there is an optimized condition to form the desired vertical interconnection. Overall, the etching rate decreased when the process time was longer.

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.11a
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• pp.70-70
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• 1999

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.589-592
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• 1998

The performance of inductively coupled plasma (ICP) is enhanced by axial magnetic field driven by alternating current Helmholtz coils in this work. Langmuir pobe is used to characterize the plasma, and the etching performance is demonstrated with phororesist stripping process. It is shown that its density and uniformity depends on the frequency of driving current to the magnetic field.