• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.200-201
• /
• 2008

태양전지 제작 시 반사방지막(Anti-reflection Coating)이 태양전지 효율에 미치는 영향을 알아보기 위한 실험으로 최적의 가스비를 알아보기 위하여 Plasma Enhanced Chemical Vapor Deposition(PECVD)를 이용한 Silicon nitride 증착 실험이다. SiH4 가스를 45 sccm으로 고정시킨 상태에서 NH3를 25,45,60,90,135 sccm으로 가변하여 Carrier Lifetime과 Refractive index를 측정하였다. PECVD의 조건은 기판온도 $450^{\circ}C$, Chamber 압력 1 Torr, 증착두께 $1000\AA$으로 고정하였다. 증착 후 500, 600, 700, $800^{\circ}C$로 열처리를 하고나서 Carrier Lifetime을 측정하여 열처리에 대한 효과도 알아보았다.

• Journal of the Semiconductor & Display Technology
• /
• v.7 no.1
• /
• pp.41-45
• /
• 2008

We studied the electrical characteristics of low-k SiOCR interlayer dielectric(ILD) films fabricated by plasma enhanced chemical vapor deposition (PECVD). The precursor bis-trimethylsilylmethane (BTMSM) was introduced into the reaction chamber with the various flow rates. The absorption intensities of Si-O-$CH_x$, bonding group and Si-$CH_x$, bonding group changed synchronously for the variation of precursor flow rate, but the intensity of Si-O-Si(C) responded asynchronously with the $CH_x$, combined bonds. The SiOCH films revealed ultra low dielectric constant around 2.1(1) and reduced further below 2.0 by heat treatments.

• Applied Science and Convergence Technology
• /
• v.23 no.3
• /
• pp.139-144
• /
• 2014

GaN deposition equipment and processes for the fabrication of white LEDs (Light Emitting Diode) using MOCVD (Metal Organic Chemical Vapor Deposition) were numerically modeled to analyze the effects of a reactive gas introduction strategy. The source gases, TMGa and $NH_3$, were injected from a shower head at the top of the chamber; the carrier gases, $H_2$ or $N_2$, were introduced using two types of injection structures: vertical and horizontal. Wafers sat on the holder at a radial distance between 100 mm and 150 mm. The non-uniformity of the deposition rates for vertical and horizontal injection were 4.3% and 3.1%, respectively. In the case of using $H_2$ as a carrier gas instead of $N_2$, the uniform deposition zone was increased by 20%.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1997.05b
• /
• pp.223-230
• /
• 1997

최근들어 그 활용도가 점점 증대되고 있는 DLU(Diamond-like Carbon) /Diamond 박막(thin film)의 합성기술을 개발하여 원자력분야에 응용하고자 시도하였다. 이를 위하여 13.56 MHz의 고주파(RF: radio-frequency)를 사용하는 플라즈마 화학증착(PECVD: Plasma Enhanced Chemical Vapor Deposition) 장치를 직접 제작하여 탄소함유(CH$_4$, $CO_2$...등) 기체로부터 기본적인 DLC 박막증착시험을 수행하였다. 실험은 진공증착기(vacuum chamber)내의 압력(pressure), 탄소함유 기체의 조성비, 그리고 바이어스전압(negative self-bias voltage)둥을 변화시키면서 수행하였다. 증착속도(deposition rate)는 증착층의 두께를 알파스템($\alpha$-step)으로 측정하여 결정하였으며, 이로부터 증착속도가 압력 및 바이어스 전압의 증가에 따라 증가함을 알 수 있었다. 또한 바이어스 전압 300V 이상에서 $CO_2$량 증가가 증착속도를 촉진시킨다는 사실도 확인하였다. 그리고 EPMA(electron probe micro-analyser) 및 Raman 스펙트럼분석을 통하여 증착층의 구조가 DLC 임을 확인하였다.

• Journal of Industrial Technology
• /
• v.43 no.1
• /
• pp.49-55
• /
• 2023

Cluster tools are extensively employed in various wafer fabrication processes within the semiconductor manufacturing industry, including photo lithography, etching, and chemical vapor deposition. Contemporary fabrication facilities encounter customer orders with technical specifications that are similar yet slightly varied. Consequently, modern fabrications concurrently manufacture two or three different wafer types using a cluster tool to maximize chamber utilization and streamline the flow of wafer lots between different process stages. In this review, we introduce two methods of concurrent processing of multiple wafer types: 1) concurrent processing of multiple wafer types with different job flows, 2) concurrent processing of multiple wafer types with identical job flows. We describe relevant research trends and achievements and discuss future research directions.

• Korean Journal of Materials Research
• /
• v.17 no.1
• /
• pp.31-36
• /
• 2007

Nanoimprint lithography (NIL) is a new lithographic method that offers a sub-10nm feature size, high throughput, and low cost. One of the most serious problems of NIL is the stiction between mold and resist. The antistiction layer coating is very effective to prevent this stiction and ensure the successful NIL results. In this paper, an antistiction layer was deposited by VSAM (vapor self assembly monolayer) method on silicon samples with FOTS (perfluoroctyltrichlorosilane) as a precursor for making an antistiction layer. A specially designed LPCVD (low pressure chemical vapor deposition) was used for this experiment. All experiments were achieved after removing the humidity. First, the evaporation test of FOTS was performed for checking the evaporation temperature at low pressure. FOTS was evaporated at 5 Tow and $110^{\circ}C$. In order to evaluate the temperature effect on antistiction layer, chamber temperature was changed from 50 to $170^{\circ}C$ with 0.1ml of FOTS for 1 minute. Good hydrophobicity of all samples was shown at about $110^{\circ}$ of contact angle and under $20^{\circ}$ of hysteresis. The surface energies of all samples calculated by Lewis acid/base theory was shown to be about 15mN/m. The deposited thicknesses of all samples measured by ellipsometry were almost 1nm that was similar value of the calculated molecular length. The surface roughness of all samples was not changed after deposition but the friction force showed relatively high values and deviations deposited at under $110^{\circ}$. Also the white circles were founded in LFM images under $110^{\circ}$. High friction forces were guessed based on this irregular deposition. The optimized VSAM process for FOTS was achieved at $170^{\circ}C$, 5 Torr for 1 hour. The hot embossing process with 4 inch Si mold was successfully achieved after VSAM deposition.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.9
• /
• pp.536-542
• /
• 2018

Tin dioxide, $SnO_2$, is a well-known n-type semiconductor that shows change in resistance in the presence of gas molecules, such as $H_2$, CO, and $CO_2$. Considerable research has been done on $SnO_2$ semiconductors for gas sensor applications due to their noble property. The nanomaterials exhibit a high surface to volume ratio, which means it has an advantage in the sensing of gas molecules. In this study, SnO nanoplatelets were grown densely on Si substrates using a thermal CVD process. The SnO nanostructures grown by the vapor transport method were post annealed to a $SnO_2$ phase by thermal CVD in an oxygen atmosphere at $830^{\circ}C$ and $1030^{\circ}C$. The pressure of the furnace chamber was maintained at 4.2 Torr. The crystallographic properties of the post-annealed SnO nanostructures were investigated by Raman spectroscopy and XRD. The change in morphology was confirmed by scanning electron microscopy. As a result, the SnO nanostructures were transformed to a $SnO_2$ phase by a post-annealing process.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.227.2-227.2
• /
• 2015

세포를 부착하는 기술은 세포를 배양하기 위한 가장 기초적이며 중요한 기술이다. 세포 부착기술은 대상물과 세포 간의 다양한 생물학적, 물리화학적 연관 관계가 있으나 세포와 부착 대상물 간의 복잡한 상호작용 때문에 완벽히 예측하기는 어렵다. 우리는 이 연구에서 siloxane 성분을 포함하고 있는 전구체인 tetrakis(trimethylsilyloxy)silane과 hydro-carbon을 포함하고 있는 전구체인 cyclohexane을 혼합하여 플라즈마 중합 박막을 만들고 그 박막에서의 mouse embryonic fibroblast cells과 bovine aortic endothelial cell 부착의 정도를 확인하였다. 플라즈마 중합 박막을 제작하기 위해 capacitively coupled plasma chemical vapor deposition system을 사용하였고 carrier gas로는 Ar을 사용하였다. Plasma RF power는 13.56MHz 70W를 사용하였다. Bubbler에서 기화된 전구체를 포함하고 있는 Ar carrier gas가 process chamber에서 혼합되고 두 전구체의 비율을 조절하기 위해 carrier gas를 0 에서 150sccm으로 변화시켜 플라즈마 중합 박막을 제작하였다. 플라즈마 중합 박막의 화학적 조성은 Fourier transform infrared absorption spectroscopy와 X-ray photoelectron spectroscopy를 이용하여 측정하였고, 생물학적 세포 부착 정도는 현미경을 통해 관찰하였다. 또한, 물과 박막의 접촉각(Water contact angle)을 측정함으로써 본 박막과 세포 부착에서의 친, 소수성의 연관성을 확인하였다. Tetrakis(trimethylsilyloxy)silane를 전구체를 사용한 박막에서 세포 부착 억제 표면특성이 관찰되었고, 주입되는 cyclohexane 비율이 늘어날수록 세포부착 가능한 표면 특성을 보였다. 결과적으로, 전구체인 tetrakis(trimethylsilyloxy)silane와 cyclohexane의 비율을 조절함으로써 세포의 부착정도를 제어할 수 있음을 확인하였다.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.03a
• /
• pp.137-137
• /
• 2003

Conducting PPy/PVA composite and pure PPy gas sensors were prepared by in-situ vaporstate polymerization method in a vaporization chamber under N2 condition, by exposing the pre-coated electrode with PVA/FeC13 to distilled pyrrole monomer. The various electrical sensing behaviors of both types of sensors were systematically investigated by a flow measuring system including mass flow controller (MFC) and bubbling bottle. The FT-Raman spectroscopy of vapor state polymerized PPy was identical to that of chemically polymerized PPy, confirming the same chemical structure. Both types of sensors had positive sensitivity when exposed to methanol gas. The sensitivity varied linearly with gas concentration in the range of 50ppm to 1059ppm. The detection limit of PPy/PVA sensor was believed to be as low as 10ppm. The sensitivity of PPy/PVA composite sensor was higher than that of pure PPy sensor. Both the response time and recovery time of PPy/PVA composite sensors were longer than those of pure PPy sensors. The thickness of the sensing film affected the sensitivity this way that the sensor having thinner film had higher sensitivity, indicating that the resistance of polymer film involved in the sensing behavior was bulk resistance rather than surface resistance. The reproducibility of PPy/PVA composite sensor was excellent during eight on-off cycles by switching between N2 and 3000ppm methanol gas. The sensitivity of PPy/PVA composite sensor was only maintained for two weeks, while the sensitivity of pure PPy sensor was maintained over two months.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.9 no.1
• /
• pp.173-186
• /
• 1999

To utilize diffuse sampling of formaldehyde in air, a new sampler was designed. A glass fiber filter was impegnated with 2,4-dinitrophenylhydrazine(DNP) and phosphoric acid and mounted 37mm cassette. The formaldehyde vapor was sampled in the dynamic chamber and measured by high performance liquid chromatograph and compared with solid sorbent tube. The results were as follows ; 1. The desorption efficiencies of diffusive sampler between 97.0% and 100%. 2. the sampling rate is constant as in $58{\sim}61.8m{\ell}/min$ when sampling times are between 120 and 360 min. 3. There was a significant relationship between concentrations of diffusive samples and active samples with the coefficient of determination(R2) of 0.92. 4. Desorbed amount of formaldehyde diffusive sampler was increased by high relative humidity. 5. Wheth diffusive samplers were stored at room temperature or at refrigerator there was no statistically significant difference in the accuracy of result. 6. When the diffusive samplers, which collected formaldehyde vapor, were exposed to clean air for three hours, there was no significant loss of formaldehyde due to reverse diffusion. In conclusion, this study suggest that developed diffusive samplers will be a reasonable substitute for the solid sorbent tube for sampling formaldehyde and practical comparative study of developed diffusive sampler should be performed at workplaces of manufacturing industry.