• Journal of the Korean Physical Society
• /
• v.73 no.9
• /
• pp.1399-1404
• /
• 2018

This study used an inductively coupled plasma (ICP) dry etching process with a metal amplitude mask to fabricate a double-side notched long-period fiber grating (DNLPFG) for loading sensing. The DNLPFG exhibited increasing resonance attenuation loss for a particular wavelength when subjected to loading. When the DNLPFG was subjected to force loading, the transmission spectra were changed, showing a with wavelength shift and resonance attenuation loss. The experimental results showed that the resonant dip of the DNLPFG increased with increasing loading. The maximum resonant dip of the $40-{\mu}m$ DNLPFG sensor was -26.522 dB under 0.049-N loading, and the largest force sensitivity was -436.664 dB/N. The results demonstrate that the proposed DNLPFG has potential for force sensing applications.

• Journal of Korean Vacuum Science & Technology
• /
• v.3 no.2
• /
• pp.116-120
• /
• 1999

Possible role of hydrogen atoms on the formation of microcrystalline silicon films was schematically investigated using a plasma enhanced chemical vapor deposition system. A layer-by-layer technique that can alternate deposition of ${\alpha}$-Si thin film and then exposure of H2 plasma was used for this end. The experimental process was extensively carried out under different hydrogen plasma times (t2) at a fixed number of 20 cycles in the deposition. structural properties, such as crystalline volume fractions and grain shapes were analyzed by using a Raman spectroscopy and a scanning electron microscopy. Electrical transports were characterized by the temperature dependence of the dark conductivity that gives rise to the calculation of activation energy (Ea). Optical absorption was measured using an ultra violet spectrophotometer, resulting in the optical energy gap (Eopt). Our experimental results indicate that both of the hydrogen etching and the structural relaxation effects on the film surface seem to be responsible for the growth mechanism of the crystallites in the ${\mu}$c-si films.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.185.2-185.2
• /
• 2016

The plasma density is an essential plasma parameter describing plasma physics. Furthermore, it affects the throughput and uniformity of plasma processing (etching, deposition, ashing, etc). Therefore, a novel technique for plasma density measurement has been attracting considerable attention. Microwave probe is a promising diagnostic technique. Various type of cutoff, hairpin, impedance, transmission, and absorption probes have been developed and investigated. Recently, based on the basic type of probes, modified flat probe (curling and multipole probes), have been developing for in situ processing plasma monitoring. There is a need for comparative study between the probes. It can give some hints on choosing the reliable probe and application of the probes. In this presentation, we make attempt of numerical study of different kinds of microwave probes. Characteristics of frequency spectrum from probes were analyzed by using three-dimensional electromagnetic simulation. The plasma density, obtained from the spectrum, was compared with simulation input plasma density. The different microwave probe behavior with changes of plasma density, sheath and pressure were found. To confirm the result experimentally, we performed the comparative experiment between cutoff and hairpin probes. The sheath and collision effects are corrected for each probe. The results were reasonably interpreted based on the above simulation.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.11 no.1
• /
• pp.43-51
• /
• 2009

The cotton, wool, cotton/wool blended(80:20) and tencel fabrics were treated with low temperature oxygen or argon plasma, enzymes(cellulase or protease), or oxygen plasma-enzyme and examined for their weight loss and conditions for treatment for the environment friendly finishing. In the plasma treatment argon gas had better effect on the weight loss than oxygen gas did and the weight loss of all the fabrics was increased as increasing discharge power and discharge time. The weight loss of cotton, wool, cotton/wool blended(80:20) fabrics decreased in a large measure after 1 hr but that of tencel didn't decrease after 1 hr. In case of cellulose fibers oxygen gas plasma induced chemical functional groups on the surface of substrate more than argon gas plasma did so the weight loss of wool was larger than that of cotton, tencel fabrics in oxygen plasma-enzyme treatment. The weight loss of cotton and tencel fabrics decreased the initial stage because oxygen plasma pre-treatment caused cross linking as well as etching effect but argon plasma pre-treatment didn't. The plasma pre-treatment cleared the way for enzyme treatment on the whole but oxygen plasma pre-treatment bear in hand the increase of weight loss more or less because of the cross linking on the surface of cellulose fibers. The appropriate conditions for plasma treatment was 10-1Torr, 40W for 30minutes and for cellulase treatment were enzyme concentration of $3g/{\ell}$, pH 5, $60^{\circ}C$ for 1hr and for protease treatment were enzyme concentration of $4g/{\ell}$ pH 8, $60^{\circ}C$ for 1hr.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.169-169
• /
• 2008

To keep pace with scaling trends of CMOS technologies, high-k metal oxides are to be introduced. Due to their high permittivity, high-k materials can achieve the required capacitance with stacks of higher physical thickness to reduce the leakage current through the scaled gate oxide, which make it become much more promising materials to instead of $SiO_2$. As further studying on high-k, an understanding of the relation between the etch characteristics of high-k dielectric materials and plasma properties is required for the low damaged removal process to match standard processing procedure. There are some reports on the dry etching of different high-k materials in ICP and ECR plasma with various plasma parameters, such as different gas combinations ($Cl_2$, $Cl_2/BCl_3$, $Cl_2$/Ar, $SF_6$/Ar, and $CH_4/H_2$/Ar etc). Understanding of the complex behavior of particles at surfaces requires detailed knowledge of both macroscopic and microscopic processes that take place; also certain processes depend critically on temperature and gas pressure. The choice of $BCl_3$ as the chemically active gas results from the fact that it is widely used for the etching o the materials covered by the native oxides due to the effective extraction of oxygen in the form of $BCl_xO_y$ compounds. In this study, the surface reactions and the etch rate of $Al_2O_3$ films in $BCl_3/Cl_2$/Ar plasma were investigated in an inductively coupled plasma(ICP) reactor in terms of the gas mixing ratio, RF power, DC bias and chamber pressure. The variations of relative volume densities for the particles were measured with optical emission spectroscopy (OES). The surface imagination was measured by AFM and SEM. The chemical states of film was investigated using X-ray photoelectron spectroscopy (XPS), which confirmed the existence of nonvolatile etch byproducts.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.459-459
• /
• 2012

Recently, the discharge of global warming gases in dry etching process of TFT-LCD display industry is a serious issue because perfluorocarbon compound (PFC) gas causes global warming effects. PFCs including CF4, C2F6, C3F8, CHF3, NF3 and SF6 are widely used as etching and cleaning gases. In particular, the SF6 gas is chemically stable compounds. However, these gases have large global warming potential (GWP100 = 24,900) and lifetime (3,200). In this work, we chose C3F6O gas which has a very low GWP (GWP100 = <100) and lifetime (< 1) as a replacement gas. This study investigated the effects of the gas flow ratio of C3F6O/O2 and process pressure in dual-frequency capacitively coupled plasma (CCP) etcher on global warming effects. Also, we compared global warming effects of C3F6O gas with those of SF6 gas during dry etching of a patterned positive type photo-resist/silicon nitride/glass substrate. The etch rate measurements and emission of by-products were analyzed by scanning electron Microscopy (SEM; HITACI, S-3500H) and Fourier transform infrared spectroscopy (FT-IR; MIDAC, I2000), respectively. Calculation of MMTCE (million metric ton carbon equivalents) based on the emitted by-products were performed during etching by controlling various process parameters. The evaluation procedure and results will be discussed in detail.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2012.11a
• /
• pp.171-171
• /
• 2012

In this study, we fabricated the high-brightness AlGaInP-based red light emitting diodes (LED)s using by direct printing technique and inductive coupled plasma (ICP) reactive ion etching (RIE). In general, surface roughening was fabricated by wet etching process to improve the light extraction efficiency of AlGaInP-based red LED. However, a structure of the surface roughening, which was fabricated by wet etching, was tiled cone-shape after wet etching process due to crystal structure of AlGaInP materials, which was used as top-layer of red LED. This tilted cone-shape of surface roughening can improve the light extraction of LED, but it caused a loss of the light extraction efficiency of LED. So, in this study, we fabricated perfectly cone shaped pattern using direct printing and dry etching process to maximize the light extraction efficiency of LED. Both submicron pattern and micron pattern was formed on the surface of red LED to compare the enhancement effect of light extraction efficiency of LEDs according to the diameter of sapphire patterns.After patterning process using direct printing and ICP-RIE proceeded on the red LED, light output was enhanced up to 10 % than that of red LED with wet etched structure. This enhancement of light extraction of red LED was maintained after packaging process. And as a result of analyze of current-voltage characteristic, there is no electrical degradation of LED.

• Journal of the Semiconductor & Display Technology
• /
• v.7 no.1
• /
• pp.1-5
• /
• 2008

In this paper, we fabricated pressure difference type gas flow sensor using only dry etching technology by ICP-RIE(inductive coupled plasma reactive ion etching). The sensor's structure consists of a common shear stress type piezoresistive pressure sensor with an orifice fabricated in the middle of the sensor diaphragm. Generally, structure like diaphragm is fabricated by wet etching technology using TMAH, but we fabricated diaphragm by only dry etching using ICP-RIE. To equalize the thickness of diaphragm we applied insulator($SiO_2$) layer of SOI(Si/$SiO_2$/Si-sub) wafer as delay layer of dry etching. Size of fabricated diaphragm is $1000{\times}1000{\times}7\;{\mu}m^3$ and overall chip $3000{\times}3000{\times}7\;{\mu}m^3$. We measured the variation of output voltage toward the change of gas pressure to analyze characteristics of the fabricated sensor. Sensitivity of fabricated sensor was relatively high as about 1.5mV/V kPa at 1kPa full-scale. Nonlinearity was below 0.5%F.S. Over-pressure range of the fabricated sensor is 100kPa or more.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.403.1-403.1
• /
• 2016

일반적으로 실리콘 태양전지의 표면 텍스쳐링 공정방식은 습식 텍스쳐링 방식과 건식 텍스쳐링 방식 2가지로 나뉘어진다. 하지만 현재 습식 텍스쳐링 방식의 경우 Solution을 사용하기 때문에 폐용액으로 인한 환경오염 및 Wafer 오염과 같은 단점을 가지고 있다. 또한 건식 텍스쳐링 방식의 경우는 진공 상태에서 진행되므로 높은 유지 비용이 가장 큰 단점으로 대두 되고 있다. 그러므로 기존의 방식과 다르게 진공을 사용하지 않는 대기압 플라즈마 소스를 텍스쳐링 공정에 적용하였다. 본 연구에서는 대기압 플라즈마 소스로 식각한 Wafer의 반사율을 가스 종류와 유량별 측정하여 분석하였다. 측정된 반사율을 통해 대기압 플라즈마 소스가 텍스쳐링 공정에 적용할 수 있는지 확인하였다.

• Proceedings of the KIEE Conference
• /
• 1992.07b
• /
• pp.649-652
• /
• 1992

ECR(Electron Cyclotron Resonance) occure at ${\omega}_c$=${\omega}$, ${\omega}_c$:electron cycltron frequency, ${\omega}$:electromagnetic wave frequency. ECR system have several merit, 1) power transefer efficiency 2) low neutral gas pressure (below 1 mTorr) 3) high plasma density($10^{12}$ $cm^{-3}$). It is applicated variously in the field of semiconductor and new materials as the manufacturing equipment. Magnetic field in ECR system contruct resonance layer (${\omega}$=2.45GHz, $B_z$=875 Gauss) and control plasma. Plasma is almost generated at resonance layer. If the distance between substrate and resonance layer is short, uniformity of plasma is related with profile of resonance layer. Plasma have the property "Cold in Field", so directonality of magnetic field is one of the control factors of anisotropic etching. In this study, we calculate B field and flux line distribution, optimize geometry and submagnet current and improve of magnetic field directionality (99.9%) near substrate. For the purpose of calculation, vector potential A(r,z) and magnetic field B(r,z), green function and numerical integration is used. Object function for submagnet optimization is magnetic field directionality on the substrate and Powell method is used as optimization skim.