• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.244-244
• /
• 1999

Liquid Crystal Displays(LCDs) 투명성 전도막으로 사용하는 Indium Tin Oxide (ITO)의 고밀도 식각특성을 조사하였다. 특히 ITO식각의 경우, pixel electrode 전극에서 사용되는 underlayer인 SiO2, Si3N4와의 최적의 선택비를 얻는데 중점을 두고 있다. 따라서 본 실험에서는 Inductively Coupled Plasma(ICP)를 이용하여 source power, gas combination, bias voltage, pressure 및 기판온도에 따른 ITO의 식각 특성과 이의 underlayer인 SiO2, Si3N4와의 선택비를 조사하였다. Ar과 CH4를 주된 식각가스로서 사용하였으며 첨가가스로는 O2와 HBr를 사용하였다. ITO의 식각특성을 이해하기 위하여 Quadruple Mass Spectrometry(QMS), Optical emission spectroscopy(OES) 이용하였으며, 식각된 sample의 잔류물을 조사하기 위하여 X-ray photoelectron spectroscopy(XPS)를 이용하여 분석하였다. Ar gas에 적정량의 CH4 혼합이 순수한 Ar 가스로 식각한 경우에 비하여 ITO와 SiO2, Si3N4의 선택비가 높았으며, 더 높은 식각 선택비를 얻기 위하여 Ar/CH 분위기에서 첨가가스 O2, HBr을 사용하였다. Source power 및 bias 증가에 따라 ITO의 식각률은 증가하나, underlayer와의 선택비는 감소함을 보였다. 본 실험에서 측정된 ITO의 high 식각률은 약 1500$\AA$/min이며, SiO2, Si3N4와의 high selectivity는 각각 7:1, 12:1로 나타났다. ITO의 etchrate 및 선택비는 source power, bias, pressure, CH 가스첨가에 의존하였지만 기판온도에는 큰 변화가 없음을 관찰하였다. 또한 적정량의 가스조합으로 식각된 시편의 잔류물을 줄일 수 있었다.

• Journal of the Korean institute of surface engineering
• /
• v.29 no.6
• /
• pp.869-875
• /
• 1996

In this article the effects of process parameters of inductively coupled plasma etching with $SF_6$ /$N_2$/Ar mixture gas and mask materials on the etched profile of W were investigated. While the etched profile was improved by $N_2$-addition, low working presure, and reduced $SF_6$ flow rate, the etching selectity (W against SAL resist) was decreased. Due to the difficulty of W etching with single layer resist, sputter deposited $Al_2O_3$ film was used as a hardmask. Reduction of required EB resist thickness through $Al_2O_3$ mask application could reduce proximity effect during e-beam patterning, but the etch anisotropy was degraded by decreased sidewall passiviation effect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.168-168
• /
• 2008

Dimension of a transistor has rapidly shrunk to increase the speed of device and to reduce the power consumption. However, it is accompanied with several problems like direct tunneling through the gate dioxide layer and low conductivity characteristic of poly-Si gate in nano-region. To cover these faults, study of new materials is urgently needed. Recently, high dielectric materials like $Al_2O_3$, $ZrO_2$, and $HfO_2$ are being studied for equivalent oxide thickness (EOT). However, poly-Si gate is not compatible with high-k materials for gate-insulator. Poly Si gate with high-k material has some problems such as gate depletion and dopant penetration problems. Therefore, new gate structure or materials that are compatible with high-k materials are also needed. TiN for metal/high-k gate stack is conductive enough to allow a good electrical connection and compatible with high-k materials. According to this trend, the study on dry etching of TiN for metal/high-k gate stack is needed. In this study, the investigations of the TiN etching characteristics were carried out using the inductively coupled $BCl_3$-based plasma system and adding $Cl_2$ gas. Dry etching of the TiN was studied by varying the etching parameters including $BCl_3$/Ar gas mixing ratio, RF power, DC-bias voltage to substrate, and $Cl_2$ gas addition. The plasmas were characterized by optical emission spectroscopy analysis. Scanning electron microscopy was used to investigate the etching profile.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.285-285
• /
• 2011

EUVL (Extreme Ultra Violet Lithography) is one of competitive lithographic technologies for sub-30nm fabrication of nano-scale Si devices that can possibly replace the conventional photolithography used to make today's microcircuits. Among the core EUVL technologies, mask fabrication is of considerable importance since the use of new reflective optics having a completely different configuration compared to those of conventional photolithography. Therefore new materials and new mask fabrication process are required for high performance EUVL mask fabrication. This study investigated the etching properties of SnO2 (Tin Oxide) as a new absorber material for EUVL binary mask. The EUVL mask structure used for etching is SnO2 (absorber layer) / Ru (capping / etch stop layer) / Mo-Si multilayer (reflective layer) / Si (substrate). Since the Ru etch stop layer should not be etched, infinitely high selectivity of SnO2 layer to Ru ESL is required. To obtain infinitely high etch selectivity and very low LER (line edge roughness) values, etch parameters of gas flow ratio, top electrode power, dc self - bias voltage (Vdc), and etch time were varied in inductively coupled Cl2/Ar plasmas. For certain process window, infinitely high etch selectivity of SnO2 to Ru ESL could be obtained by optimizing the process parameters. Etch characteristics were measured by on scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses. Detailed mechanisms for ultra-high etch selectivity will be discussed.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.1462-1464
• /
• 2006

Scaling rules for TFT application devices have led to the necessity of ultra thin dielectric films and high-k dielectric layers. In this paper, The advantages of high concentration of nitrogen in silicon oxide layer deposited by using $N_2O$ in Inductively Coupled Plasma Chemical Vapor Deposition (ICP-CVD) is investigated using X-ray energy dispersive spectroscopy (EDS). We have reported about Ellipsometric measurement, Capacitance - Voltage characterization and processing conditions.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.5 no.4
• /
• pp.318-331
• /
• 1995

The c - axis oriented single crystal of $LiNbO_3$ and $LiNbO_3$ : 5mol%MgO was success-fully grown by Floating zone method using halogen lamp as a heat source. The effects of the sintering condition of the feed rod and the atmosphere gas during the crystal growth on the be havior of the feed rod/melt interface were studied for growing crystal with the high quality, and then, the optimum growth conditions were determined by studying the experimental param eters, such as gas flow rate, pulling rate, rotation speeds of the feed rod and the seed. The grown crystals were analyzed using the chemical etching to observe the tch pattern and the ICP (Inductively Coupled Plasma) to determine the composition uniformity and the impurity content of Fe. The effects of additive (5 mol % MgO) on the transmittance and refractive index was, also, analyzed. In order to compare the nonlinear optical oharacteristics of $LiNbO_3$ with those of the other optical materials, the nonlinear optical refractive index ($n_2$) was calcu l lated using the measured refractive index.

• Journal of the Korean Vacuum Society
• /
• v.6 no.3
• /
• pp.267-274
• /
• 1997

Silicon shallow trenches applied to the STI (Shallow Trench Isolation) of integrated circuits were etched using inductively coupled $Cl_2$ and HBr/$Cl_2$ plasmas and the effects of process parameters on the etch profiles of silicon trenches and the physical damages on the trench sidewall and bottom were investigated. The increase of inductive power and bias voltage in $Cl_2$ and HBr/$Cl_2$ plasmas increased polysilicon etch rates in general, but reduced the etch selectivities over nitride. In case of $Cl_2$ plasma, low inductive power and high bias voltage showed an anisotropic trench etch profile, and also the addition of oxygen or nitrogen to chlorine increased the etch anisotropy. The use of pure HBr showed a positively angled etch profile and the addition of $Cl_2$ to HBr improved the etch profile more anisotropically. HRTEM study showed physical defects formed on the silicon trench surfaces etched in $Cl_2/N_2$ or HBr/ $Cl_2$ plasmas.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.4
• /
• pp.373-377
• /
• 2004

We have investigated the electrical characterization of metal-oxide-semiconductor (MOS) capacitors formed on the inductively coupled plasma (ICP) etch-damaged both n- and p-type 4H-SiC. We found that there was an effect of a sacrificial oxidation treatment on the etch-damaged surfaces. Current-voltage and capacitance-voltage measurements of these MOS capacitors were used and referenced to those of prepared control samples without etch damage. It has been found that a sacrificial oxidation treatment can improve the electrical characteristics of MOS capacitors on etch-damaged 4H-SiC since the effective interface density and fixed oxide charges of etch-damaged samples have been found to increase while the breakdown field strength of the oxide decreased and the barrier height at the SiC-SiO$_2$ interface decreased for MOS capacitors on etch-damaged surfaces.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.287-287
• /
• 2011

ITRS(international technology roadmap for semiconductors)에 따르면 MOS (metal-oxide-semiconductor)의 CD(critical dimension)가 45 nm node이하로 줄어들면서 poly-Si/SiO2를 대체할 수 있는 poly-Si/metal gate/high-k dielectric이 대두되고 있다. 일반적으로 metal gate를 식각시 정확한 CD를 형성시키기 위해서 plasma를 이용한 RIE(reactive ion etching)를 사용하고 있지만 PIDs(plasma induced damages)의 하나인 PICD(plasma induced charging damage)의 발생이 문제가 되고 있다. PICD의 원인으로 plasma의 non-uniform으로 locally imbalanced한 ion과 electron이 PICC(plasma induced charging current)를 gate oxide에 발생시켜 gate oxide의 interface에 trap을 형성시키므로 그 결과 소자 특성 저하가 보고되고 있다. 그러므로 본 연구에서는 이에 차세대 MOS의 metal gate의 식각공정에 HDP(high density plasma)의 ICP(inductively coupled plasma) source를 이용한 중성빔 시스템을 사용하여 PICD를 줄일 수 있는 새로운 식각 공정에 대한 연구를 하였다. 식각공정조건으로 gas는 HBr 12 sccm (80%)와 Cl2 3 sccm (20%)와 power는 300 w를 사용하였고 200 eV의 에너지로 식각공정시 TEM(transmission electron microscopy)으로 TiN의 anisotropic한 형상을 볼 수 있었고 100 eV 이하의 에너지로 식각공정시 하부층인 HfO2와 높은 etch selectivity로 etch stop을 시킬 수 있었다. 실제 공정을 MOS의 metal gate에 적용시켜 metal gate/high-k dielectric CMOSFETs의 NCSU(North Carolina State University) CVC model로 effective electric field electron mobility를 구한 결과 electorn mobility의 증가를 볼 수 있었고 또한 mos parameter인 transconductance (Gm)의 증가를 볼 수 있었다. 그 원인으로 CP(Charge pumping) 1MHz로 gate oxide의 inteface의 분석 결과 이러한 결과가 gate oxide의 interface trap양의 감소로 개선으로 기인함을 확인할 수 있었다.

• Korean Journal of Materials Research
• /
• v.16 no.3
• /
• pp.151-156
• /
• 2006

A method for fabrication of nano-scale GaN structure by inductively coupled plasma etching is proposed, exploiting a thermal dewetting of Pt thin film as an etch mask. The nano-scale Pt metal islands were formed by the dewetting of 2-dimensional film on $SiO_2$ dielectric materials during rapid thermal annealing process. For the case of 30 nm thick Pt films, pattern formation and dewetting was initiated at temperatures greater $600^{\circ}C$. Controlling the annealing temperature and time as well as the thickness of the Pt metal film affected the size and density of Pt islands. The activation energy for the formation of Pt metal island was calculated to be 23.2 KJ/mole. The islands show good resistance to dry etching by a $CF_4$ based plasma for dielectric etching indicating that the metal islands produced by dewetting are suitable for use as an etch mask in the fabrication of nano-scale structures.