Monte Carlo N-Particle Extended 코드를 이용한 연X선 정전기제거장치의 최적설계에 관한 연구

정필훈 ( Phil Hoon Jeong ),이동훈 ( Dong Hoon Lee ) 한국안전학회 2017 한국안전학회지 Vol.32 No.2

In recent emerging industry, Display field becomes bigger and bigger, and also semiconductor technology becomes high density integration. In Flat Panel Display, there is an issue that electrostatic phenomenon results in fine dust adsorption as electrostatic capacity increases due to bigger size. Destruction of high integrated circuit and pattern deterioration occur in semiconductor and this causes the problem of weakening of thermal resistance. In order to solve this sort of electrostatic failure in this process, Soft X-ray ionizer is mainly used. Soft X-ray Ionizer does not only generate electrical noise and minute particle but also is efficient to remove electrostatic as it has a wide range of ionization. X-ray Generating efficiency has an effect on soft X-ray Ionizer affects neutralizing performance. There exist variable factors such as type of anode, thickness, tube voltage etc., and it takes a lot of time and financial resource to find optimal performance by manufacturing with actual X-ray tube source. MCNPX (Monte Carlo N-Particle Extended) is used for simulation to solve this kind of problem, and optimum efficiency of X-ray generation is anticipated. In this study, X-ray generation efficiency was measured according to target material thickness using MCNPX under the conditions that tube voltage is 5 keV, 10 keV, 15 keV and the target Material is Tungsten(W), Gold(Au), Silver(Ag). At the result, Gold(Au) shows optimum efficiency. In Tube voltage 5 keV, optimal target thickness is 0.05 ㎛ and Largest energy of Light flux appears 2.22×10⁸ x-ray flux. In Tube voltage 10 keV, optimal target Thickness is 0.18 ㎛ and Largest energy of Light flux appears 1.97×10⁹ x-ray flux. In Tube voltage 15 keV, optimal target Thickness is 0.29 ㎛ and Largest energy of Light flux appears 4.59×10⁹ x-ray flux.

MCNPX 코드를 이용한 방사선조사방식 정전기제거장치에서 최적구조의 방호조건 설계에 관한 연구

정필훈(Phil-Hoon Jeong) 한국산학기술학회 2022 한국산학기술학회논문지 Vol.23 No.11

OLED 및 반도체 제조 공정에서 정전기 장해로 불량이 증가하여 제조 수율이 낮아지고 있다. 이러한 정전기 문제를 해결하기 위해 도입된 정전기 제거장치는 전압인가방식과 방사선조사방식의 정전기 제거장치가 사용된다. 전압인가방식 정전기 제거장치는 오염물질 발생, 스패터링 현상, 이온 불균형, 정전유도작용 등의 문제점이 있어 주기적인 관리가 필요하다. 방사선조사방식의 정전기 제거장치는 부유미립자 등의 오염물질이 발생하지 않으며 제전시간이 신속하고, 넓은 제전범위 등 많은 장점이 있어 OLED 및 반도체 제조공정에 적합하지만 방사선 차폐에 대한 대책이 필요하다. 본 연구에서는 방사선조사방식 정전기 제거장치의 문제점인 방사선 누출에 대한 대책으로 방호장치를 설계하였다. 방사선이 발생하는 관로를 1차측, 방사선이 누출되지 않도록 꺾은 관로를 2차측으로 하였다. 이 방호장치를 MCNPX 코드로 시뮬레이션한 결과 1) 1차측 12㎜, 2차측 5.5㎜인 경우 방사선 누출량은 0.18μSv/h. 2) 1차측 12.5㎜, 2차측 13㎜인 경우에서 방사선 누출량은 0.15μSv/h. 3) 1차측 20㎜, 상부로 향한 2차측 7㎜인 경우 방사선 누출량은 0.11 μSv/h로 나타났다. 이 방호장치를 활용하여 방사선 노출이 없는 방사선조사방식 정전기제거장치를 제조하고자 한다. In OLED and semiconductor manufacturing processes, electrostatic interference increases defects and lowers manufacturing yields. A voltage application ionizer and a radiation irradiation ionizer are used to solve electrostatic problems. The voltage application ionizer has problems such as pollutant generation, spattering, ion imbalance, and electrostatic induction, so periodic management is required. The radiation irradiation ionizer has several advantages, so it is used in OLED and semiconductor manufacturing processes, but radiation issues must be resolved. In this study, protective devices are designed to solve radiation leakage problems. The pipe that emits radiation is the primary side, and the pipe that is bent to prevent radiation from leaking is the secondary side. Simulation results with MCNPX code are as follows: 1) primary length, 12mm; secondary length, 5.5mm, for radiation leakage at 0.18μ Sv/h; 2) primary length, 12.5mm; secondary length, 13mm, for radiation leakage at 0.15μSv/h; 3) primary length, 20mm; secondary length toward the top, 7mm, for radiation leakage at 0.11μSv/h. Applying these results, an attempt is made to manufacture, without radiation exposure, a radiation irradiation ionizer for protective devices.

완전차폐 및 이온조절형 연X선식 정전기제거장치의 개발

정필훈 ( Phil Hoon Jeong ),이동훈 ( Dong Hoon Lee ) 한국안전학회(구 한국산업안전학회) 2016 한국안전학회지 Vol.31 No.5

The Electrostatic Charge Prevention Technology is a core factor that highly influences the yield of Ultra High Resolution Flat Panel Display and high-integrated semiconductor manufacturing processes. The corona or x-ray ionizations are commonly used in order to eliminate static charges during manufacturing processes. To develop such a revolutionary x-ray ionizer that is free of x-ray radiation and has function to control the volume of ion formation simultaneously is a goal of this research and it absolutely overcomes the current risks of x-ray ionization. Under the International Commission on Radiological Protection, it must have a leakage radiation level that should be lower than a recommended level that is 1μSv/hour. In this research, the new generation of x-ray ionizer can easily control both the volume of ion formation and the leakage radiation level at the same time. In the research, the test constraints were set and the descriptions are as below; First, In order not to leak x-ray radiation while testing, the shielding box was fully installed around the test equipment area. Second, Implement the metallic Ring Electrode along a tube window and applied zero to ±8 kV with respect to manage the positive and negative ions formation. Lastly, the ion duty ratio was able to be controlled in different test set-ups along with a free x-ray leakage through the metallic Ring Electrode. In the result of experiment, the maximum x-ray radiation leakage was 0.2μSv/h. These outcome is lower than the ICRP 103 recommended value, which is 1μSv/h. When applying voltage to the metallic ring electrode, the positive decay time was 2.18s at the distance of 300 ㎜ and its slope was 0.272. In addition, the negative decay time was 2.1s at the distance of 300 ㎜ and its slope was 0.262. At the distance of 200 ㎜, the positive decay time was 2.29s and its slope was 0.286. The negative decay time was 2.35s and its slope was 0.293. At the distance of 100 ㎜, the positive decay time was 2.71s and its slope was 0.338. The negative decay time was 3.07s and its slope was 0.383. According to these research, the observation was shown that these new concept of ionizer is able to minimize the leakage radiation level and to control the positive and negative ion duty ratio while ionization.

감압대기 및 불활성가스 분위기에서 적합한 정전기 제거장치의 개발

이동훈 ( Dong Hoon Lee ),정필훈 ( Phil Hoon Jeong ),이수환 ( Su Hwan Lee ),김상효 ( Sang Hyo Kim ) 한국안전학회(구 한국산업안전학회) 2016 한국안전학회지 Vol.31 No.3

In LCD Display or semiconductor manufacturing processes, the anti-static technology of glass substrates and wafers becomes one of the most difficult issues which influence the yield of the semiconductor manufacturing. In order to overcome the problems of wafer surface contamination various issues such as ionization in decompressed vacuum and inactive gas(i.e. N2 gas, Ar gas, etc.) environment should be considered. Soft X ray radiation is adequate in air and O2 gas at atmospheric pressure while UV radiation is effective in N2 gas Ar gas and at reduced pressure. At this point of view, the “vacuum ultraviolet ray ionization” is one of the most suitable methods for static elimination. The vacuum ultraviolet can be categorized according to a short wavelength whose value is from 100 ㎚ to 200 ㎚. this is also called as an Extreme Ultraviolet. Most of these vacuum ultraviolet is absorbed in various substances including the air in the atmosphere. It is absorbed substances become to transit or expose the electrons, then the ionization is initially activated. In this study, static eliminator based on the vacuum ultraviolet ray under the above mentioned environment was tested and the results show how the ionization performance based on vacuum ultraviolet ray can be optimized. These vacuum ultraviolet ray performs better in extreme atmosphere than an ordinary atmospheric environment. Neutralization capability, therefore, shows its maximum value at 10-1~10-3 Torr pressure level, and than starts degrading as pressure is gradually reduced. Neutralization capability at this peak point is higher than that at reduced pressure about 104 times on the atmospheric pressure and by about 103 times on the inactive gas. The introductions of these technology make it possible to perfectly overcome problems caused by static electricity and to manufacture ULSI devices and LCD with high reliability.

p-Xylene의 농도 변화에 따른 폭발압력과 폭발압력상승속도의 실험적 연구

유삼열(Sam-Yeol Yoo),최유정(Yu-Jung Choi),정필훈(Phil-Hoon Jeong),최재욱(Jae-Wook Choi) 한국산학기술학회 2022 한국산학기술학회논문지 Vol.23 No.11

p-Xylene은 석유화학업계에서 합성원료, 페인트, 도료, 페트병, 폴리에스터 섬유 등을 제조하는 원료 및 용제로 사용되고 있다. 하지만 위험물안전관리법 시행령에 따르면 p-Xylene은 제 4류 위험물 중 제 2 석유류로서 인화점이 낮아 점화원이 있는 경우 화재나 폭발의 위험이 있어 제조, 유통, 보관 시에 주의하여야 한다. 폭발은 급격하게 진행되는 화학반응을 통해 반응에 관여하는 물질이 부피를 확장 시키고 빛, 소리, 충격 압력을 동반하는 반응으로서 농도, 온도, 압력, 산소 및 착화원 등에 따라서 폭발범위가 달라지므로 이를 파악할 필요가 있다. 따라서 본 연구는 p-Xylene의 비점 부근인 150 ℃에서 압력이 1.0 kg/cm2.G일 때 p-Xylene의 농도 변화에 따른 폭발압력 및 폭발압력상승속도를 구하였다. p-Xylene의 농도가 1.55%에서 2.35%로 증가할수록 최대 폭발압력은 5.66 kg/㎠.G에서 6.63 kg/㎠.G로 증가하였으며, 최대 폭발압력상승속도는 124.39 kg/㎠.G·s에서 196.41 kg/㎠.G·로 증가하였다. 또한 가연성 혼합기체가 착화되기 위해 필요한 최소한의 에너지는 p-Xylene의 농도가 1.55%에서 2.35%로 증가할수록 1.44 mJ에서 0.24 mJ로 낮아지는 경향을 확인하였다. P-xylene is used as raw material and solvent for manufacturing various products in the petrochemical industry. According to the Safety Control of Dangerous Substances Act, p-xylene is categorized as one of the Class 4 dangerous substances. Due to its low flash point, there is a risk of fire or explosion from p-xylene in the presence of ignition sources. In an explosion, the material involved expands in volume through a rapidly progressing chemical reaction and is accompanied by light, sound, and impact pressure. Since an explosion range varies depending on the concentration, temperature, pressure, oxygen, and ignition sources, it is necessary to understand these factors. This study was undertaken to measure the explosion pressure and its rise rate according to changes in the p-xylene concentration when the pressure was 1.0 kg/㎠.G at 150°C, which is near the boiling point of p-xylene. As the p-xylene concentration increased from 1.55% to 2.35%, the maximum explosion pressure increased from 5.66 kg/㎠.G to 6.63 kg/㎠.G, and the maximum explosion pressure rise rate increased from 124.39 kg/㎠.G·s to 196.41 kg/㎠.G·s. Furthermore, the minimum energy required for the combustible gas mixture to ignite decreased from 1.44 mJ to 0.24 mJ with an increasing concentration of p-xylene.