• 한국항공우주학회지
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• 제35권6호
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• pp.533-538
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• 2007

위성 탑재체의 지향성능을 향상시키기 위하여 반수동 진동제어법을 제안하고, 시뮬레이션에 의해 진동절연 효과를 검증하였다. 본 논문에서 제안한 반수동 진동제어법은 고주파수 영역에서의 저댐핑 수동제어와, 구조물의 공진을 포함하는 저주파수 영역에서의 고댐핑 수동제어가 갖는 진동절연 효과를 동시에 만족시키기 위해 고안되었다. 시뮬레이션 결과는 반수동 진동제어법이 상기의 효과를 구현하는데 있어 효과적임을 나타낸다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권9호
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• pp.438-443
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• 2001

In the shallow trench isolation(STI)-chemical mechanical polishing(CMP) process, the key issues are the optimized thickness control, within-wafer-non-uniformity, and the possible defects such as pad oxide damage and nitride residue. The defect like nitride residue and silicon (or pad oxide) damage after STI-CMP process were discussed to accomplish its optimum process condition. To understand its optimum process condition, overall STI related processes including reverse moat etch, trench etch, STI fill and STI-CMP were discussed. Consequently, we could conclude that law trench depth and high CMP thickness can cause nitride residue, and high trench depth and over-polishing can cause silicon damage.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.25-28
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• 2001

Recently, STI(Shallow Trench Isolation) process has attracted attention for high density of semiconductor device as a essential isolation technology. Without applying the conventional complex reverse moat process, CMP(Chemical Mechanical Polishing) has established the Process simplification. However, STI-CMP process have various defects such as nitride residue, torn oxide defect, damage of silicon active region, etc. To solve this problem, in this paper, we discussed to determine the control limit of process, which can entirely remove oxide on nitride from the moat area of high density as reducing the damage of moat area and minimizing dishing effect in the large field area. We, also, evaluated the reliability and reproducibility of STI-CMP process through the optimal process conditions.

• Archives of Pharmacal Research
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• 제5권1호
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• pp.7-12
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• 1982

Ginsenosides Rb1, Rb2, Rc, Rd, Re, Rf and Rg1 were effectively isolated from ginseng root by preparative liquid chromatography (LC) on two PrepPAK-500/c18 cartridges in series and semipreparative LC on a .mu. Bondapak cabohydrate analysis column, a .mu.Bondapak C18 column or a .mu. Porasil column. The identities of the isolated ginsenosides were confirmed by analytical high-performance liquid chromatography (HPLC) and infrared spectrophotometry. By this method large scale isolation of pure ginsenosides was efficiently accomplished.

• ETRI Journal
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• 제31권3호
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• pp.342-344
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• 2009

From a hydrodynamic device simulation for the pseudomorphic high electron mobility transistors (pHEMTs), we observe an increase of maximum extrinsic transconductance and a decrease of source-drain capacitances. This gives rise to an enhancement of the switching speed and isolation characteristics as the upper-to-lower planar-doping ratios (UTLPDR) increase. On the basis of simulation results, we fabricate single-pole-double-throw transmitter/receiver monolithic microwave integrated circuit (MMIC) switches with the pHEMTs of two different UTLPDRs (4:1 and 1:2). The MMIC switch with a 4:1 UTLPDR shows about 2.9 dB higher isolation and approximately 2.5 times faster switching speed than those with a 1:2 UTLPDR.

• ALGAE
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• 제22권2호
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• pp.125-129
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• 2007

Conventional methods for the isolation and purification of mRNA from Zygnema were unsuccessful because of its high amount of pigments and RNA interactive molecules. In particular, pigments were difficult to remove using conventional protocols because they interacted with RNA during pulverization of the materials. This resulted in total degeneration of RNA in two to three hours. To alleviate this problem, we developed an isolation method that utilized DEAE-cellulose resin. The pigments bound to DEAE anion exchange resin and separated from the RNA. Purified total RNA showed an yield of 50 μg per 100 mg of tissue with this method. The amplified 2nd strand cDNA was distributed 300 bp and over.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.174-176
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• 2007

Because of accident or leak of electricity, high voltage electricity can be conducted to vehicle chassis and damage human. Therefore the unit for detecting ground fault is necessary to minimize loss of life or equipment damage. Isolation resistance must be monitored for detecting ground fault. GFD(Ground Fault Detection) unit continually generate the pulse voltage between high voltage network and chassis. This will be sensing the returned current, calculate the isolation resistance and make decision the ground fault. This paper describes the method detecting ground fault.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권10호
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• pp.441-446
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• 2003

The chemical mechanical polishing (CMP) process is now widely employed in the ultra large scale integrated (ULSI) semiconductor fabrication. Especially, shallow trench isolation (STI) has become a key isolation scheme for sub-0.13/0.10${\mu}{\textrm}{m}$ CMOS technology. The most important issues of STI-CMP is to decrease the various defects such as nitride residue, dishing, and tom oxide. To solve these problems, in this paper, we studied the planarization characteristics using slurry additive with the high selectivity between $SiO_2$ and $Si_3$$N_4$ films for the purpose of process simplification and in-situ end point detection. As our experimental results, it was possible to achieve a global planarization and STI-CMP process could be dramatically simplified. Also, we estimated the reliability through the repeated tests with the optimized process conditions in order to identify the reproducibility of STI-CMP process.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.501-504
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• 1999

In the shallow trench isolation(STI) chemical mechanical polishing(CMP) process, the key issues are the optimized thickness control within- wafer-non-uniformity, and the possible defects such as nitride residue and pad oxide damage. These defects after STI CMP process were discussed to accomplish its optimum process condition. To understand its optimum process condition, overall STI related processes including reverse moat etch, trench etch, STI filling and STI CMP were discussed. It is represented that the nitride residue can be occurred in the condition of high post CMP thickness and low trench depth. In addition there are remaining oxide on the moat surface after reverse moat etch. It means that reverse moat etching process can be the main source of nitride residue. Pad oxide damage can be caused by over-polishing and high trench depth.

• KIEE International Transactions on Electrophysics and Applications
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• 제3C권1호
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• pp.28-32
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• 2003

In this paper, we have studied the in-situ end point detection (EPD) for direct chemical mechanical polishing (CMP) of shallow trench isolation (STI) structures without the reverse moat etch process. In this case, we applied a high selectivity $1n (HSS) that improves the silicon oxide removal rate and maximizes oxide to nitride selectivity Quite reproducible EPD results were obtained, and the wafer-to-wafer thickness variation was significantly reduced compared with the conventional predetermined polishing time method without EPD. Therefore, it is possible to achieve a global planarization without the complicated reverse moat etch process. As a result, the STI-CMP process can be simplified and improved using the new EPD method.